罗普司亭在脓毒症相关血小板减少症的应用探索与机制分析

Platelets, traditionally known for their role in hemostasis, have emerged as key players in immune response and inflammation. Sepsis, a life-threatening condition characterized by systemic inflammation, often presents with thrombocytopenia, which at times, can be significant. Platelets contribute to the inflammatory response by interacting with leukocytes, endothelial cells, and the innate immune system. However, excessive platelet activation and consumption can lead to thrombocytopenia and exacerbate the severity of sepsis. Understanding the multifaceted roles of platelets in sepsis is crucial for developing effective therapeutic strategies. Targeting platelet-mediated inflammatory responses and promoting platelet production may offer potential avenues for improving outcomes in septic patients with thrombocytopenia. Future research should focus on elucidating the mechanisms underlying platelet dysfunction in sepsis and exploring novel therapeutic approaches to optimize platelet function and mitigate inflammation. This review explores the intricate relationship between platelets, inflammation, and thrombosis in the context of sepsis.

Thrombocytopenia (TCP) is a common finding in critically ill patients that has been linked to a worse prognosis. Specifically, sepsis is a major risk factor for TCP. Several observational studies have examined the prognostic role of TCP and its correlation with clinical outcomes in patients with sepsis. We conducted a systematic search through Medline, Scopus and CENTRAL, from inception until June 2024, in order to identify studies that discussed the effects of TCP on clinical outcomes in patients with sepsis or septic shock. This review was performed in accordance with the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Study endpoints were ICU mortality, 28-day mortality, major bleeding and mechanical ventilation. We included twelve studies enrolling 14,093 patients in this meta-analysis. TCP was diagnosed at intensive care unit (ICU) admission in 5481 (39%) patients; on the other hand, it was encountered during the course of ICU stay in 1474 (10%) cases. Patients with TCP had significantly higher risks of ICU mortality (Odds Ratio: 1.93, 95% CI [1.6–2.33]; p < 0.01). and 28-day mortality (odds ratio: 1.98, 95% CI [1.67, 2.35]; p < 0.00001). Furthermore, patients with severe TCP (platelet count < 50 * 109/L) had even higher odds of ICU mortality (odds ratio: 3.38, 95% CI [2.25, 5.08]; p < 0.00001). Major bleeding events were significantly more frequent in patients with TCP (odds ratio: 3.26, 95% CI [2.26, 4.72]; p < 0.01). TCP exhibits significant clinical implications in critically ill patients admitted with sepsis and is associated with enhanced mortality and worse clinical outcomes. Nonetheless, this meta-analysis quantifies the significant association between TCP and poor clinical outcomes in patients with sepsis and septic shock.

Thrombocytopenia is a prevalent complication and an adverse prognostic factor in sepsis; however, there is a paucity of studies examining the dynamic changes in platelet counts and their association with the prognosis of sepsis patients with related thrombocytopenia. This study aims to retrospectively to investigate the relationship between the dynamic trajectories of platelet counts and early adverse prognostic outcomes in such patients. A retrospective observational study was conducted using data from 946 sepsis patients with thrombocytopenia extracted from the Medical Information Mart for Intensive Care (MIMIC-IV) database. A joint latent class model (JLCM) was employed to analyze platelet trajectories over time as part of a time series analysis (TSA). Time-dependent piecewise Cox regression models and Kaplan-Meier survival curves were utilized to evaluate the association between trajectory patterns and 60-day mortality. Sensitivity analyses included the Schoenfeld residual test, subgroup analysis and reclassification of groups based on corresponding mortality risks. The platelet trajectories during the first 28 days of hospitalization were classified into four classes, each associated with distinct 60-day mortality risks. Class 1 consistently remained at the lowest level, while Class 2 exhibited a gradual increase, yet still remained below normal levels. Class 3 demonstrated a rapid increase to normal levels, and Class 4 continued to increase closely toward normal level. The multivariable Cox proportional hazards model, with Class 1 as the reference group and adjusted for potential confounders, revealed significant associations between the trajectories and 60-day mortality for Class 3 (HR 0.27, 95% CI 0.08–0.85, P = 0.025) and Class 4 (HR 0.68, 95% CI 0.48–0.96, P = 0.029). Class 2 suggested a non-significant trend toward higher early mortality (HR 1.38, 95% CI 0.85–2.24, P = 0.198). Kaplan-Meier curves from the multivariate analysis indicated that Class 1 had the lowest 60-day survival probability, while Class 3 exhibited the highest, followed by Class 4. After merging Classes 1 and 2 into Group 1 for sensitivity analysis, with Group 1 as the reference, the groups remained significantly associated with 60-day mortality. The Schoenfeld residual test, subgroup analysis, regrouping were performed as sensitivity analyses to ensure the robustness of our study results. This study demonstrates that trajectories of platelet in sepsis patients with thrombocytopenia is clinically significant. Sustained low platelet levels or low amplitude increases that remain below normal levels indicate a higher early mortality rate. Early rapid increase of platelet count is associated with better prognosis.

Introduction Sepsis associated thrombocytopenia (SAT) is a common complication of sepsis. We designed this study to investigate factors influencing SAT. Methods Patients with sepsis (2984 in Peking union medical college hospital [PUMCH] database, 13165 in eICU Collaborative Research [eICU] database, 11101 in Medical Information Mart for Intensive Care IV [MIMIC-IV] database) were enrolled. Variables included basic information, comorbidities, and organ functions. Multi-variable logistic regression models and artificial neural network model were applied to determine the factors related to SAT. Main results Age and body mass index (BMI) were inversely correlated with the incidence of SAT (p-value 0.175 and 0.049 [PUMCH], p-value 0.000 and 0.000 [eICU], p-value 0.000 and 0.000 [MIMIC-IV]). Hematologic malignancies and other malignancies were positively correlated with the incidence of SAT (p-value 0.000 and 0.000 [PUMCH], p-value 0.000 and 0.000 [eICU], p-value 0.000 and 0.020 [MIMIC-IV]) except other malignancies was inversely correlated with the incidence of SAT in PUMCH database. Norepinephrine (NE) equivalents, total bilirubin (TBIL) and creatinine were positively correlated with the incidence of SAT (p-value 0.000, 0.000 and 0.011 [PUMCH], p-value 0.028, 0.000 and 0.013 [eICU], p-value 0.028, 0.000 and 0.027 [MIMIC-IV]). PaO2 / FiO2 was inversely correlated with the incidence of SAT in PUMCH database (p-value 0.021 [PUMCH]), while it was positively correlated with the incidence of SAT (p-value 0.000 [MIMIC-IV]). PaO2 / FiO2 and SAT was not related (p-value 0.111 [eICU]). TBIL, hematologic malignancies, PaO2 / FiO2 and NE equivalents ranked in the top five significant variables in all three datasets. Conclusions Hematologic malignancies and other malignancies were positively correlated with the incidence of SAT. NE equivalents, TBIL and creatinine were positively correlated with the incidence of SAT. TBIL, hematologic malignancies, PaO2 / FiO2 and NE equivalents ranked in the top significant variables in factors influencing SAT.

Background: Early and accurate diagnosis of neonatal sepsis remains a clinical challenge due to nonspecific signs and limitations of conventional biomarkers. The immature platelet fraction (IPF), a novel hematologic parameter reflecting thrombopoietic activity, has emerged as a potential early sepsis indicator. This study aimed to evaluate the diagnostic value of IPF in neonatal sepsis prior to the onset of thrombocytopenia. Methods: This prospective study enrolled neonates with early-onset sepsis (EOS), late-onset sepsis (LOS), and healthy controls. IPF, C-reactive protein (CRP), procalcitonin (PCT), and hematologic indices were measured at diagnosis and 48–72 h post-treatment. Diagnostic performance was evaluated via ROC curve analysis, and correlations between IPF and inflammatory/hematologic markers were examined. IPF levels were also compared based on blood culture results. Results: IPF levels were significantly higher in both EOS (n: 56) and LOS (n: 50) groups compared to controls (n: 44) (p < 0.001). ROC analysis showed excellent diagnostic performance, with AUCs of 0.98 (EOS) and 0.99 (LOS). Following antibiotic treatment, IPF levels declined significantly (p < 0.001), supporting its dynamic value. Strong and moderate correlations were found with MPV and CRP, respectively, and an inverse association with platelet count, but not with PCT. Moreover, IPF levels were higher in culture-positive cases compared to culture-negative ones (13.1% vs. 9.8%; p = 0.017) and exhibited diagnostic performance comparable to CRP in predicting blood culture positivity. Conclusions: This study presents original and clinically relevant data supporting IPF as a promising and practical hematologic biomarker for early detection and treatment monitoring of neonatal sepsis. Its integration into standard sepsis evaluation protocols may improve early risk stratification and clinical decision-making in neonatal intensive care settings.

Background this study aimed to investigate the efficacy of recombinant human thrombopoietin (rhTPO) in the treatment of sepsis-associated thrombocytopenia, and to evaluate its impact on coagulation function, inflammatory markers, platelet (Plt) count, and patient prognosis. Methods a total of 144 patients with sepsis-associated thrombocytopenia, admitted to our hospital between 2022 and 2023, were selected for the study. The patients were randomly divided into two groups using a random number table: the control group (Group C, n = 72) and the research group (Group R, n = 72). The Group C received standard treatment, while the Group R received rhTPO in addition to standard care. We compared the general demographic data, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, coagulation parameters, serum levels of Toll-like receptor 4 (TLR4), interleukin-6 (IL-6), serum creatinine (SCr), tumor necrosis factor-alpha (TNF-α), Plt count, transfusion volume, treatment duration, incidence of complications, and mortality rates between the two groups. Results there were no significant differences in the general demographic characteristics between the two groups (P > 0.05). After treatment, the APACHE II scores in both groups significantly decreased, with a more pronounced reduction observed in the Group R. Coagulation function indicators, including activated partial thromboplastin time (APTT), fibrinogen (FIB), plasminogen activator inhibitor-1 (PAI-1), antithrombin III (AT-III), protein C, thrombomodulin (TM), and Plt factor 4 (PF4), showed greater improvement in the Group R compared to the Group C (P < 0.05). The serum levels of TLR4, IL-6, and TNF-α in the Group R were significantly lower than those in the Group C (P < 0.05), whereas no significant difference in SCr levels was observed between the groups (P > 0.05). The Plt count in the Group R began to significantly increase on day 3 of treatment, and was consistently higher than that in the Group C on days 3, 5, and 7 (P < 0.05). The Group R required significantly fewer red blood cell transfusions compared to the Group C and did not require Plt suspension (P < 0.05). No significant differences were found between the groups in terms of mechanical ventilation time, intensive care unit (ICU) length of stay, and total hospital stay (P > 0.05). However, the ICU and overall hospital mortality rates were significantly lower in the Group R than in the Group C (P < 0.05). Multivariate logistic regression analysis indicated that rhTPO treatment was an independent protective factor for reducing mortality (OR = 0.475, P = 0.042). Conclusion rhTPO treatment effectively improves coagulation function and inflammatory status in patients with sepsis-associated thrombocytopenia, increases Plt count, reduces transfusion requirements, and lowers mortality. These findings suggest that rhTPO has significant clinical application value in the management of this condition.

Objective: To evaluate the prevalence of thrombocytopenia observed in neonates admitted to the hospital with sepsis. Methods: A total of 103 patients, including both males and females with ages below 28 days, who were admitted to the NICU (neonatal intensive care unit) with gram-negative sepsis were enrolled in this study. Blood samples were collected from each patient for sepsis and platelet analysis on the 1st and 3rd day of patients’ admission and sent to the Ghurki Hospital laboratory for analysis. Thrombocytopenia was defined as platelet counts <150,000/mm3. Thrombocytopenia was classified as mild, moderate, and severe. The type of organism and mortality rate related to thrombocytopenia were also recorded. Results: Of 103 neonates, 64 (62.13%) were males while 39 (37.86%) were females. 88 (85.43%) had thrombocytopenia (p <0.001) whereas 15 (14.56%) had normal platelet count. E. coli was found to be the most common organism responsible for gram-negative sepsis. On day one, 61 (59.22%) patients had normal platelet count whereas 12 (11.65%), 14 (13.59%), & 16 (15.53%) neonates had mild, moderate & severe thrombocytopenia respectively. In contrast, on the third day, 18 (17.47%) neonates had normal platelet count, 6 (5.82%) had mild, 33 (32.03%) had moderate, and 46 (44.66%) had severe thrombocytopenia. 12/103 (11.65%) patients died, out of which 11 (10.68%) had thrombocytopenia. Conclusion: Thrombocytopenia is a significant marker of gram-negative sepsis in neonates. Keywords: Neonate, Neonatal Intensive Care Unit, Thrombocytopenia, Sepsis.

BACKGROUND Sepsis-induced thrombocytopenia (SIT) is a frequent hematological complication in critically ill patients. However, the independent risk factors for SIT remain controversial. This meta-analysis aims to identify independent predictors of SIT in adult septic patients. OBJECTIVE To identify risk factors for SIT and explore their potential implications for early risk stratification and platelet-targeted intervention in sepsis. METHODS PubMed, Embase, Cochrane Library, Web of Science, CNKI, and Wanfang databases were searched from inception to April 2025. Studies reporting multivariable-adjusted associations between candidate risk factors and SIT were included. Data extraction and quality assessment were performed independently by two reviewers. Newcastle-Ottawa Scale was used for quality assessment. Pooled odds ratios (ORs) and mean differences (MDs) were calculated using RevMan 5.3 and Stata 15.0. RESULTS A total of 14 studies involving 14,316 septic patients were included. The pooled incidence of SIT was 37.9 %. In the primary analysis using the conventional threshold of PLT <100 × 109 L-1, elevated lactate, higher SOFA scores, and lower WBC count were associated with SIT. Subgroup analyses at PLT <150 × 109 L-1 yielded consistent results for lactate and WBC, while SOFA retained significance only at the stricter definition. No significant publication bias was detected. CONCLUSIONS This meta-analysis demonstrated that elevated serum lactate, higher SOFA scores, and lower white blood cell count are significantly associated with SIT. Given the structural overlap between SOFA score and thrombocytopenia, further studies are needed to validate its independent role. Early identification of these predictors may help improve risk stratification and clinical management in septic patients.

Summary Thrombocytopenia (TP) in patients with sepsis is associated with adverse outcomes. Previous research has predominantly focused on the severity of TP, while the prognostic impact of its duration remains insufficiently explored. This study aimed to investigate the association between the duration of sepsis-associated thrombocytopenia (SAT) and clinical outcomes. Over a 28-day observation period, patients with persistent TP (duration > 3 days) had significantly fewer ventilator-free days, intensive care unit (ICU)-free days, and hospital-free days (all p < 0.001) than those with transient TP (resolution within 1–3 days). Persistent TP was associated with significantly increased mortality (p < 0.001) and transfusion rates (p < 0.001). Multivariable logistic regression analysis revealed that transient TP was not significantly associated with in-hospital mortality (p > 0.05), whereas persistent TP remained an independent risk factor (p < 0.05). A 3-day cutoff to differentiate between transient and persistent SAT demonstrated significant clinical utility. The duration of TP offers additional, valuable prognostic information, potentially guiding risk stratification and therapeutic strategies.

Objective: Markedly elevated serum ferritin serves as a laboratory marker of macrophage activation syndrome and is associated with increased mortality in sepsis, where hyperinflammation, coagulopathy, and immune dysregulation interplay. Although laboratory studies suggest a relationship between hyperferritinemia and coagulopathy in sepsis, clinical evidence remains limited. This study aims to assess mortality risk and the interplay between hyperferritinemia (ferritin ≥ 500 ng/mL) and thrombocytopenia in two sequential cohorts of adult patients with sepsis. Patients: Patients with sepsis (≥18 years old) admitted to adult ICUs at Beth Israel Deaconess Medical Center between 2001 and 2008, and 2008 to 2019, with at least one ferritin value recorded within a 48-h window preceding or following the initial ICU admission. Results: Among 2339 eligible patients with hyperferritinemic sepsis, 921(39.4%) were categorized into the high ferritin (HF) group (ferritin ≥ 500 ng/mL). Multivariate logistic regression analysis revealed a significant association between the HF group and increased in-hospital mortality (p < .01). Survival analysis revealed significantly lower survival probabilities at 28 and 90 days in the HF group compared to the low ferritin group. The interaction between the HF group and thrombocytopenia revealed a statistically significant association with in-hospital mortality. Furthermore, causal mediation analysis showed that platelet count mediated 12.6% (95% CI: 0.063-0.27; p < .001) of the effect of elevated ferritin levels on in-hospital mortality. Conclusions: Hyperferritinemia is associated with an increased mortality risk in adult septic patients. Thrombocytopenia not only interacts with hyperferritinemia but also serves as a mediating factor in its impact on mortality.

Objective Given the high morbidity and mortality of patients with sepsis-associated thrombocytopenia (SATP) in the intensive care unit, this study retrospectively analysed the influencing factors for poor prognosis in patients with SATP using the MIMIC database, constructed a nomogram model and verified the predictive performance of the model. Design A retrospective cohort study. Setting The data from MIMIC-IV, V.2.2. Clinical characteristics The clinical features of SATP, including demographics, comorbidities, vital signs, laboratory parameters, treatments and clinical management, were extracted from the MIMIC-IV database. Methods 1409 patients with SATP were included in this study and randomly divided into a training set and a validation set in a ratio of 7:3. The least absolute shrinkage and selection operator and multivariable Cox regression analysis were used to determine the optimal predictors and establish a prediction model. The receiver operating characteristic curve, calibration curve and decision curve analysis (DCA) were used to verify the accuracy and application value of the model. Results The nomogram model incorporates nine factors, including clinical characteristics, laboratory test indicators, comorbidities and treatment methods, which were identified as predictors of SATP and used to construct the model. The area under the curve of the model was 0.868 (95% CI: 0.794 to 0.942) in the training set and 0.836 (95% CI: 0.681 to 0.991) in the validation set. The calibration curve and DCA confirmed the clinical application value of the nomogram. Conclusions The constructed nomogram for predicting patients with SATP has favourable predictive ability and is helpful to further optimise clinical management strategies.

Background: Neonatal sepsis is serious infection in first 28 days of life and it can cause many hematological problems. One common problem is thrombocytopenia which increase risk of bleeding and poor outcome. Objective: To determine the frequency and severity of thrombocytopenia in neonates with sepsis. Study Design: Descriptive cross-sectional study. Duration and Place of Study: Conducted from 5 April 2024 to 5 October 2024 at Neonatal Intensive Care Unit, Combined Military Hospital Abbottabad. Methodology: A total of 136 culture positive septic neonates aged ≤28 days were included by calculated sample size. Demographic and clinical data were recorded. Thrombocytopenia was noted. Data was analyzed by Statistical Package for Social Sciences version 26. Mean ± standard deviation was calculated for quantitative variables. Chi-square test was applied after stratification and p ≤0.05 was taken significant. Results: Mean age was 14.49 ± 7.99 days and mean weight 2.97 ± 0.51 kg. Thrombocytopenia was found in 85 (62.50%) neonates. Among them, mild was 23 (27.10%), moderate 31 (36.50%) and severe 31 (36.50%). Age >14 days showed higher thrombocytopenia 49 (71.0%) compared to ≤14 days 36 (53.7%) (p=0.037). Gender, mode of delivery and feeding type had no significant association (p>0.05). Conclusion: Thrombocytopenia is common in neonatal sepsis and most cases are moderate to severe. Increasing age is significant associated factor.

Background and Aim: Neonatal sepsis continues to be a major cause of morbidity and mortality in developing countries. It is one of the most frequent hematologic complications in neonatal sepsis and it could be useful clinical marker for the severity of the illness. The present study was conducted to find out the frequency of thrombocytopenia in neonates of sepsis managed at NICU, Combined Military Hospital (CMH) Peshawar. Patients and Methods: This was a cross-sectional study conducted on 139 neonates (1–28 days of age) presenting to NICU, CMH, Peshawar during October 2024 to March 2025, with clinically and laboratory proven sepsis. An electronic hematology analyzer determined platelet counts. Thrombocytopenia was diagnosed based on a platelet count less than 150,000/µL and classified as mild (100,000–149,000/µL), moderate (50,000–99,000/µL) or severe (<50,000/µL). Demographic and clinical details collected and analyzed by descriptive statistics. Results: Among 139 neonates with sepsis, 82 (59%) was found to be thrombocytopenia. Of these, mild thrombocytopenia was observed in 25 (30.5%), moderate in 36 (43.9%), and 21 (25.6%) severe in neonates. The prevalence was more with the preterm neonates and late-onset sepsis. Male neonates represented slightly more ratio of cases with thrombocytopenia. Conclusion: Thrombocytopenia is a common hematological finding in neonates with sepsis, affecting more than half of the affected population in the NICU. Routine monitoring of platelet counts in septic neonates recommended for early identification and management, potentially improving clinical outcomes and reducing complications.

No abstract available

Neonatal sepsis is a major cause of morbidity and mortality, often complicated by thrombocytopenia, which increases the risk of bleeding and worsens prognosis. Reported frequencies of thrombocytopenia in septic neonates vary widely, and local data are limited.  Objectives: To determine the frequency of thrombocytopenia in septic neonates and its association with clinical and laboratory parameters. Methods: This cross-sectional study was conducted at the Department of Paediatrics, DHQ Hospital, Dera Ismail Khan, over six months. A total of 110 septic neonates were enrolled. Demographics, clinical presentations, and laboratory findings were recorded. Blood samples were analyzed for platelet count, white blood cell count, C-reactive protein (CRP), and blood cultures. Data were analyzed using SPSS Version 25, with chi-square and Mann-Whitney U tests applied. Logistic regression identified predictors of thrombocytopenia, with p<0.05 considered significant. Results: Thrombocytopenia was found in 69.1% of septic neonates. Early-onset sepsis was significantly associated with thrombocytopenia (p=0.032), while blood culture results, bacterial pathogen type, CRP, and White Blood Cells (WBC) count were not. Mechanical ventilation showed a significant association (p=0.033), and thrombocytopenic neonates had higher mortality (p=0.053). Logistic regression identified mechanical ventilation (p=0.047, OR=0.386) as a significant predictor, while early-onset sepsis showed borderline significance (p=0.056, OR=2.489). Conclusions: It was concluded that thrombocytopenia is common in septic neonates, with early-onset sepsis and mechanical ventilation as key risk factors. Routine platelet monitoring in critically ill neonates is essential for timely intervention.

Sepsis, a life-threatening condition triggered by a dysregulated immune response to infection, remains one of the leading causes of mortality worldwide. Thrombocytopenia, a common sepsis complication, is linked to poor outcomes and reflects disease severity and specific immunological changes affecting patient outcomes. This study aimed to investigate transcriptomic differences between septic patients with and without thrombocytopenia and to explore immune features related to clinical outcomes using whole-transcriptome RNA sequencing (RNA-Seq). We conducted a prospective study on 52 patients who were admitted to ICU for sepsis, including 22 with thrombocytopenia and 30 without. Blood samples were collected on both day 1 and 8, and RNA-Seq was performed to analyze transcriptomic profiles. Differentially expressed genes (DEGs) were identified, and functional enrichment analyses were conducted to explore biological pathways and processes. T-cell receptor (TCR) diversity was assessed using MiXCR and VDJTools software. Thrombocytopenic critically ill septic patients exhibited significantly higher Sequential Organ Failure Assessment (SOFA) scores and mortality rates compared to non-thrombocytopenic patients. Transcriptomic analysis revealed distinct gene expression profiles between the two groups, with marked upregulation of myeloproliferative and T-cell activation signaling pathways in thrombocytopenic patients on day 1. Additionally, TCR diversity counts showed no statistically significant differences between thrombocytopenic and non-thrombocytopenic patients at day 1 or day 8. Thrombocytopenia in septic ICU patients is associated with altered heme/porphyrin metabolism, erythrocyte development, and immune activation. Lower TCR diversity on day 1 in thrombocytopenic patients suggests early immune repertoire perturbations; however, these findings should be interpreted cautiously and validated with targeted immune repertoire sequencing.

Acquired amegakaryocytic thrombocytopenia (AATP) is a rare disorder in which severely low platelet levels occur due to reduced or complete absence of megakaryocytes in the bone marrow. The pathophysiology of this disease is not fully understood, although anti-thyroid peroxidase antibodies (anti-TPO) binding to cellular-myeloproliferative leukemia (c-mpl) receptors is a proposed mechanism. Currently, no standard published guideline for treatment exists, but immunosuppressive therapies have been used based on the proposed mechanism and associated conditions. We present a case of a 57-year-old male who presented to the hospital with a 3-day history of progressive weakness and dysphagia. He had recently been discharged from an outside health system after evaluation for suspected gastrointestinal bleeding, although esophagogastroduodenoscopy and colonoscopy did not uncover a source of bleeding. Fifteen days later, he was admitted to our hospital for septic shock and acute renal failure with suspected lower gastrointestinal bleeding (melena on presentation). He was found to have a rapidly declining platelet count with a nadir of 0. Due to severe thrombocytopenia, filgrastim was administered. A bone marrow biopsy revealed findings consistent with amegakaryocytosis with otherwise preserved cell lines. Hematologic labs improved with the initiation of appropriate treatment for severe sepsis. After performing an extensive workup, the likely etiology of transient AATP in this case was severe sepsis-induced immune dysregulation and bone marrow suppression.

Mycoplasma pneumoniae (M. pneumoniae), as one of the susceptible pathogens during childhood, may lead to severe mycoplasmal pneumonia and affect platelet fluctuations. We prospectively collected data on persistent/chronic ITP children who were infected with M. pneumoniae infection from August 2023 to December 2023. There were 64 patients (40 males) with a median age of 7.08 years (range 4.30 to 9.76) enrolled in this study. Overall, 33 (51.6%) children received TPO-RAs therapy and 31 (48.4%) received other treatments. The impact of M. pneumoniae infection on platelet count is bidirectional, but thrombocytopenia remains predominant. During M. pneumoniae infection, platelet changes in the TPO-RA group were higher than in the non-TPO-RA group. Thrombocytosis was observed in 6 patients (5 in the TPO-RA group vs. 1 in the non-TPO-RA group). Rescue treatment was implemented in 18 patients (7 in the TPO-RA group vs. 11 in the non-TPO-RA group). Monitoring platelets should be strengthened during M. pneumoniae infection.

Megakaryocytes are traditionally recognized as cells responsible for platelet production. However, beyond their role in thrombopoiesis, megakaryocytes also participate in inflammatory responses and regulate immune system functions. Sepsis, characterized by life-threatening organ dysfunction due to a dysregulated response to infection, prominently features coagulopathy, severe inflammation, and immune dysfunction as key pathophysiological aspects. Given the diverse functions of megakaryocytes, we explore their roles in coagulation in the context of sepsis, and also in inflammatory and immune regulation. We try to infer future research directions and potential strategies for sepsis prevention and treatment based on the properties of megakaryocytes. The purpose of this review is to both highlight and provide an update on the functions of megakaryocytes and pathophysiological changes in sepsis. Specific emphasis is given to the role of megakaryocytes in sepsis, which suggests value of future research and clinical application.

Circulating cell-free DNA (cfDNA) is a promising molecular biomarker. However, its utility in severe infection remains poorly understood. Here, we isolated cfDNA from sepsis patients and controls, demonstrating a 41-fold increase in the amount of cfDNA in circulation during disease. We used sequencing to reconstruct cfDNA methylomes, fragmentation profiles, and nucleosome footprints across 56 samples. We observed no difference in cfDNA composition between patients and controls, challenging the idea that cfDNA increases due to higher immune cell death during sepsis. Instead, we suggest that liver dysfunction prevents efficient clearance of cfDNA during disease. This was supported by fragmentation and end-motif patterns, both of which showed evidence of cfDNA being exposed to circulating nucleases for a prolonged period, proportionally to the extent of liver dysfunction. Variation in cfDNA of megakaryocyte-erythroid progenitor origin was also a significant contributor in sepsis, increasing over time. Moreover, we showed that cfDNA retains nucleosome footprints with cell type-specific gene activity information. We developed a novel approach to study nucleosome phasing that successfully recovers tissue-specific signatures. By combining this with single-cell data, we demonstrated that sepsis patients with liver dysfunction have higher amounts of cfDNA derived from Kupffer cells and the liver parenchyma. In conclusion, we present the first high-throughput multi-modal study of cfDNA during sepsis, which will serve as a reference point for future studies on the role of this biomarker in critical illness.

Sepsis is a life-threatening condition characterised by an overwhelming immune response and high fatality. While most research has focused on its acute phase, many sepsis survivors remain immunologically weakened leaving them susceptible to serious complications from even mild infections. The mechanisms underlying this prolonged immune dysregulation remain unclear, limiting effective interventions. Here, we analysed whether sepsis induced long-term “training” in hematopoietic stem and progenitor cells (HSPCs), imprinting changes that persist in their myeloid progeny. Peripheral blood analysis of 8 sepsis survivors, 12 patients with septic shock, and 10 healthy donors revealed a significant expansion of CD38 + progenitors in survivors, with increased megakaryocyte-erythroid progenitors and a near significant reduction in mature neutrophil counts. This shift suggests impaired granulopoiesis, favouring immature, immunosuppressive granulocytes. Differentiated macrophages from survivors’ HSPCs exhibited impaired metabolic pathways after lipopolysaccharide stimulation, with downregulation of tricarboxylic acid cycle and glycolysis genes, indicating altered immune metabolism. Pathway analysis revealed enhanced type-I interferon (IFN) and JAK-STAT signalling in survivors’ macrophages, reflective of potentially tolerance-prone reprogramming. Finally, exposing healthy donor HSPCs to IFNβ during macrophage differentiation reduced HSPC proliferation, increased apoptosis, and induced a metabolic shift towards glycolysis over mitochondrial respiration. Together, these findings suggest that sepsis induces lasting reprogramming in HSPCs leading to myeloid progeny with altered immune memory that might drive immune dysregulation in survivors. These data open avenues to explore potential targets to better manage long-term immune alterations in sepsis survivors.

BACKGROUND Management of persistent inflammation, immunosuppression, and catabolism syndrome (PICS) after sepsis remains challenging for patients in the intensive care unit, experiencing poor quality of life and death. However, immune-cell signatures in patients with PICS after sepsis remain unclear. METHODS We determined immune-cell signatures of PICS after sepsis at single-cell resolution. Murine cecal ligation and puncture models of PICS were applied for validation. FINDINGS Immune functions of two enriched monocyte subpopulations, Mono1 and Mono4, were suppressed substantially in patients with sepsis and were partially restored in patients with PICS after sepsis and exhibited immunosuppressive and pro-apoptotic effects on B and CD8T cells. Patients with PICS and sepsis had reduced naive and memory B cells and proliferated plasma cells. Besides, naive and memory B cells in patients with PICS showed an active antigen processing and presentation gene signature compared to those with sepsis. PICS patients with better prognoses exhibited more active memory B cells and IGHA1-plasma cells. CD8TEMRA displayed signs of proliferation and immune dysfunction in the PICS-death group in contrast with the PICS-alive group. Megakaryocytes proliferation was more pronounced in patients with PICS and sepsis than in healthy controls, with notable changes in the anti-inflammatory and immunomodulatory effects observed in patients with PICS and verified in mice models. CONCLUSIONS Our study evaluated PICS after sepsis at the single-cell level, identifying the heterogeneity present within immune-cell subsets, facilitating the prediction of disease progression and the development of effective intervention. FUNDING This work was supported by the National Natural Science Foundation of China, Shanghai Municipal Health Commission "Yiyuan New Star" Youth Medical Talent Cultivating Program, and Shanghai Clinical Research Center for Anesthesiology.

Background The poor prognosis of sepsis warrants the investigation of biomarkers for predicting the outcome. Several studies have indicated that PANoptosis exerts a critical role in tumor initiation and development. Nevertheless, the role of PANoptosis in sepsis has not been fully elucidated. Methods We obtained Sepsis samples and scRNA-seq data from the GEO database. PANoptosis-related genes were subjected to consensus clustering and functional enrichment analysis, followed by identification of differentially expressed genes and calculation of the PANoptosis score. A PANoptosis-based prognostic model was developed. In vitro experiments were performed to verify distinct PANoptosis-related genes. An external scRNA-seq dataset was used to verify cellular localization. Results Unsupervised clustering analysis using 16 PANoptosis-related genes identified three subtypes of sepsis. Kaplan-Meier analysis showed significant differences in patient survival among the subtypes, with different immune infiltration levels. Differential analysis of the subtypes identified 48 DEGs. Boruta algorithm PCA analysis identified 16 DEGs as PANoptosis-related signature genes. We developed PANscore based on these signature genes, which can distinguish different PANoptosis and clinical characteristics and may serve as a potential biomarker. Single-cell sequencing analysis identified six cell types, with high PANscore clustering relatively in B cells, and low PANscore in CD16+ and CD14+ monocytes and Megakaryocyte progenitors. ZBP1, XAF1, IFI44L, SOCS1, and PARP14 were relatively higher in cells with high PANscore. Conclusion We developed a machine learning based Boruta algorithm for profiling PANoptosis related subgroups with in predicting survival and clinical features in the sepsis.

INTRODUCTION Sepsis is a Systemic Inflammatory Response (SIR) caused by invading pathogens. We aimed to characterize infiltrating cells in sepsis and provide novel insight for the treatment of sepsis. MATERIALS AND METHODS Whole-blood scRNA-seq samples from four septic patients and five healthy subjects were collected from the Gene Expression Omnibus (GEO) database (GSE175453). The Seurat R package was used for quality control and cell clustering by scRNA- seq analysis. Gene set enrichment analysis (GSEA) was performed using the clusterProfiler R package for pathway enrichment analysis. Then, the SCENIC analysis was used to identify key transcriptional regulons, and the CellChat R package was used for cell communication analysis. RESULTS We mainly obtained 9 cell clusters, including myeloid cells, T cells, dendritic cells, NKT cells, B cells, plasma B cells, megakaryocytes, mast cells and erythrocytes. Notably, myeloid cells, erythrocytes and mast cells had a higher proportion in sepsis patients. Activated IL-17 and p53 pathways supported anti-infection response in myeloid cells, and JUNB and SPI1 mediated multiple inflammatory pathways, including TNF signaling and neutrophil activation. We also identified that the cell interaction mode of myeloid cells, such as MPZL1-MPZL1 and FASL-FAS, may serve as a potential target for an anti-inflammatory response in sepsis treatment. DISCUSSIONS The scRNA-seq analysis revealed pro-inflammatory pathways (IL-17, p53) and key regulators (JUNB, SPI1) in septic myeloid cells. Receptor genes (MPZL1 and FAS) mediated cell communication, offering potential biomarkers and targets for sepsis therapy. CONCLUSION We characterized the pro-inflammatory immune response pathways, transcriptional regulon and cell interaction modes of myeloid cells in the development of sepsis.

Megakaryocytes (MKs) are specialized hematopoietic cells long recognized for their ability to produce platelets. Increasing evidence now highlights MKs as multifunctional immune effectors that bridge hematopoiesis with host immunity. In the bone marrow (BM), MKs arise through thrombopoietin (TPO)-mediated differentiation of hematopoietic stem cells (HSCs) and show substantial heterogeneity, with discrete subsets specialized for platelet production (thrombopoiesis), HSC niche maintenance, or immune modulation. Outside the BM, MKs in the lungs and spleen perform tissue-specific immune functions, including pathogen recognition, phagocytosis, antigen presentation, and secretion of cytokines. During bacterial infections and sepsis, infectious or inflammatory cues reprogram MKs to amplify immune signaling and host responses, but can also drive coagulopathy and contribute to organ failure. Collectively, these findings redefine MKs as dynamic immunomodulatory cells positioned at the interface of thrombopoiesis and innate and adaptive immunity. In this review, we synthesize emerging literature on MK biogenesis, functional diversity, and immune modulation, with a special focus on their roles in bacterial infections and sepsis.

Sepsis-induced thrombocytopenia (SIT) is a widely accepted predictor of poor prognosis during sepsis, while the mechanism of SIT remains elusive. In this study, we revealed that SIT patients and septic mice exhibited higher levels of pro-inflammatory macrophages and phosphorylated BTK (p-BTK) expression in macrophages, which were closely correlated with platelet counts. Treatment with the BTK inhibitor, BGB-3111 in SIT mice resulted in enhanced production of megakaryocytes and platelets. Depletion of macrophages in SIT mice and coculture experiments further confirmed the critical role of macrophages in the improvement of platelet count induced by BGB-3111. By performing single-cell RNA sequencing on bone marrow-derived cells from SIT mice, we not only confirmed the connection between macrophages and megakaryocytes influenced by BTK but also identified a potential mediation through the Rap1 signaling pathway in macrophages. Subsequent experiments in macrophages demonstrated that inhibition of BTK signaling impeded the pro-inflammatory polarization of macrophages by targeting the Rap1/NF-κB signaling pathway. In conclusion, our study highlights the crucial role of macrophages in SIT, and inhibiting phosphorylation of BTK in macrophages may alleviate SIT through the Rap1/NF-κB signaling pathway.

Platelets are crucial to the development of thrombosis and coagulation abnormalities in sepsis, but the mechanisms by which they contribute to these pathological processes are not fully understood. Here, we identify a key role for platelet-released heat shock protein 90α (HSP90α) in driving neutrophil extracellular trap (NET) formation and supporting thromboinflammation during sepsis. Proteomic analysis of platelets from patients with sepsis showed a significant increase in HSP90α, which we traced back to trafficking pathways originating from megakaryocytes. When activated, platelets translocate HSP90α to their plasma membrane and release it into the extracellular space in both free and exosome-associated forms. Extracellular HSP90α acts as a damage-associated molecular pattern that binds to toll-like receptor 4 (TLR4) on neutrophils. This binding activates a downstream MyD88-Beclin 1 signaling pathway, triggering autophagy and leading to NET formation. Blocking extracellular HSP90α with a neutralizing monoclonal antibody significantly reduced NET formation both in vitro and in vivo, resulting in decreased sepsis-related thrombosis and inflammation. This platelet-HSP90α-TLR4-autophagy-NET pathway not only deepens our understanding of platelet-induced immunothrombosis but also suggests potential targets for therapies aimed at reducing coagulation problems and organ failure in septic patients.

Background: Platelet hyperactivity and reduced responsiveness to antiplatelet therapies are major contributors to thrombotic complications in metabolic and inflammatory conditions such as diabetes and sepsis. These disorders are frequently accompanied by enhanced platelet activation, increased thromboxane production, and elevated thromboinflammatory responses, including cytokine release and platelet–leukocyte interactions. However, the molecular mechanisms linking these processes to platelet dysfunction remain poorly understood. Here, we identify protein arginine methyltransferase 1 (PRMT1), which is activated in diabetes and sepsis, as a central regulator that integrates metabolic, transcriptional, and inflammatory pathways to promote platelet hyperactivity, thromboinflammation, and resistance to antiplatelet agents. Methods: Using megakaryocyte-specific PRMT1 overexpression (Pf4-cre PRMT1 transgenic mice) and knockout mice (Pf4-cre Prmt1flox/floxmice). Results: PRMT1 enhanced thrombin-mediated platelet aggregation by aggregometer assays and bioflux assays, and accelerates clot formation in tail bleeding assays. Consistently, Prmt1 knockout mice exhibited a prolong bleeding time and poor performance in platelet aggregation assays. Recently, we have published that PRMT1 promotes aerobic glycolysis and attenuates respiratory complex 2 activity, which leads to an accumulation of succinate and a higher ADP/ATP ratio (Su et al. 2025). While extracellular succinate enhanced activation in wild-type platelets, it failed to augment PRMT1-high platelet activation, suggesting a saturated or bypassed succinate-GPR91 axis in these platelets. Mechanistically, PRMT1 upregulated TBXAS1, the gene encoding thromboxane synthase, via transcription factors SOX4 and RUNX1 in megakaryocytes. The resulting platelets had an increased thromboxane A2 (TXA2) production ability, making additional succinate stimulation unnecessary. Interestingly, PRMT1-high platelets cannot respond to P2Y12 inhibition with prasugrel due to PRMT1-mediated attenuation of mitochondrial respiratory capability. PRMT1 facilitates the maturation of inflammatory cytokine mRNAs (e.g., IL-1β) through RBM15-mediated splicing (Zhang et al. 2015). Given that normal platelets contain proinflammatory cytokines in pre-mRNA form, upregulated of PRMT1 in megakaryocytes leads to producing platelets with mature mRNAs enabling rapid cytokine translation upon activation. Proteomic profiling of platelets from the transgenic mice further validated the enrichment of inflammatory and antigen presentation pathways in PRMT1-high platelets.We further demonstrated the enhanced platelet–neutrophil interactions and NET formation using purified platelets and neutrophils. Dusp4 is a downstream target of PRMT1 through methylation. After methylation, Dusp4 protein is degraded via ubiquitylation. Thus, we also found the hyperactivation in platelets from the DUSP4+/- mice. Since DUSP4 knockout mice are supceptible for Leishmania infection, our data suggest that PRMT1-Dusp4 axis may be important for fighting leishmania infection or other infection. To investigate platelet heterogeneity, we added a PRMT1-specific vital dye E84 (Su et al., Blood Adv., 2018) in FACS analysis. We found that PRMT1 expression varied across the platelet pool. In diabetic mice, E84 staining detected a wider range of PRMT1 expression in platelets, supporting a link between metabolic disease and prothrombotic platelet phenotypes. Surprisingly, even in PRMT1 transgenic or knockout mice, PRMT1 heterogeneity persisted, suggesting an incomplete flox recombination reaction during megakaryopoiesis and potential lineage memory effects.Conclusion: Together, These findings elucidate a novel mechanism underlying platelet hyperactivity and antiplatelet resistance in metabolic diseases, and identify PRMT1 as a potentially promising therapeutic target in thromboinflammatory disorders.

Thrombopoietin (Tpo) is the primary regulator of megakaryocyte and platelet numbers and is required for haematopoetic stem cell maintenance. Tpo functions by binding its receptor (TpoR, a homodimeric Class I cytokine receptor) and initiating cell proliferation or differentiation. Here we characterise the murine Tpo:TpoR signalling complex biochemically and structurally, using cryo-electron microscopy. Tpo uses opposing surfaces to recruit two copies of receptor, forming a 1:2 complex. Although it binds to the same, membrane-distal site on both receptor chains, it does so with significantly different affinities and its highly glycosylated C-terminal domain is not required. In one receptor chain, a large insertion, unique to TpoR, forms a partially structured loop that contacts cytokine. Tpo binding induces the juxtaposition of the two receptor chains adjacent to the cell membrane. The therapeutic agent romiplostim also targets the cytokine-binding site and the characterisation presented here supports the future development of improved TpoR agonists.

Background: Thrombotic diseases such as myocardial infarction and stroke are closely associated with immune inflammation and high prevalent in COVID-19 and sepsis. The pathologic mechanism is due to dysregulation and hyperactivation of platelet induced thrombotic inflammation and vascular occlusion. We surprisingly found elevated expression of Nrf3 (Nuclear factor erythroid 2-related factor 3) in platelets from COVID-19 patients and septic mouse. Considering that the role of Nrf3 still remains unknown, we aimed to investigate the pathological mechanisms of Nrf3 in platelet and thrombo-inflammation. METHODS: Nrf3 global knockout mice and Nrf3 megakaryocyte/platelet-specific knockout mice were used for research. Platelet aggregation/secretion, integrin αIIbβ3 activation, spreading, clot retraction and calcium flux were measured. In vivo thrombus formation was detected in carotid thrombosis and pulmonary embolism. Lipopolysaccharide (LPS) intravenous injection was used to establish septic model and explore the effects of Nrf3 on platelet-induced thrombo-inflammation. RESULTS: We found that Nrf3 expression was increased in inflammation-stimulated platelets and positively correlated with increased platelet activity. In vitro detection indicated that deficiency of Nrf3 attenuated platelet activation without significant effects on platelet counts and other types of peripheral blood cells. Nrf3 -/- mice showed reduced thrombus formation with little tendency to hemorrhage. Additionally, we demonstrated that loss of Nrf3 reduced pro-inflammatory chemokines content (IL-1β, TNF-α and S100A4), platelet-leukocyte complex and neutrophil extracellular traps (NETs), and further alleviated micro-thrombosis and inflammatory infiltration in sepsis-induced multi-organ injury. Meanwhile, Nrf3 -/- platelets exhibited lower ATP content, oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), indicating that Nrf3 is closely involved in platelet energy metabolism. CONCLUSION: Collectively, these results demonstrated that Nrf3 regulated platelet activity, thrombosis and platelet-induced inflammation by influencing energy metabolism, suggesting that Nrf3 could be a potential target for therapeutic intervention in patients at risk of thrombo-inflammation.

Serine-threonine kinase 10 (STK10) is a member of Ste20 family of serine/threonine kinases and regulates lymphocyte adhesion. Quantitative phosphoproteomic assay showed increased STK10 phosphorylation in activated platelet. However, its role in platelet function remains unclear. In our study, we investigated the expression and role of STK10 in platelet function. We first showed STK10 expression in human and mouse platelets. By establishing megakaryocyte/platelet-specific STK10 knockout mice, we found that deletion of platelet STK10 impaired hemostasis and arterial thrombosis. Consistently, platelet aggregation, a-granule release, aIIbb3 activation, procoagulant activity, spreading and clot retraction were all reduced after deletion of STK10. Quantitative phosphoproteomic assays revealed several dysregulated phosphoproteins, which were enriched in platelet activation and focal adhesion. By using immunoprecipitation coupled to mass spectrometry and protein phosphorylation profiles screening approaches, we identified that STK10 interacts with integrin-linked protein kinase (ILK) and deletion of STK10 significantly reduced ILK phosphorylation (Ser343). Following in vitro phosphorylation assay demonstrated that STK10 directly phosphorylated ILK at Ser343. Additionally, inhibition of calcium, PKC or PI3K inhibited STK10 phosphorylation in activated platelets. Moreover, deletion of platelet STK10 reduced platelet-neutrophil interactions, neutrophil accumulation and neutrophil extracellular traps formation, ameliorated thromboinflammation, as well as increased the survival of sepsis mice. Furthermore, an increase of the activation of platelet STK10 and ILK was observed in sepsis mice and patients. In conclusion, our study identifies a novel regulatory role of STK10 in platelet function, arterial thrombosis and thromboinflammation, implying that it might be a potential target for the treatment of thrombotic or cardiovascular diseases.

Persistent inflammation-immunosuppression and catabolism syndrome (PICS) is a severe condition that may follow sepsis and is characterized by ongoing inflammation and immune suppression, diminishing quality of life and potentially causing death. The role of megakaryocytes (MKs) in PICS, despite their association with thrombopoiesis, is not well understood. In this study, we use single-cell RNA sequencing to profile MKs in peripheral blood mononuclear cell samples obtained from 11 patients, including six with PICS, five with sepsis, and five healthy controls, to determine the diversity and molecular signatures of the MKs. Five subgroups of MKs are identified (MK1–MK5), and their proportions vary across the groups. MK1 and MK2 are predominant in PICS. Gene Ontology analysis shows that genes related to antigen processing and presentation and IL-17 signaling are enriched in MK1, whereas genes associated with platelet degranulation and neutrophil activation are enriched in MK2. Moreover, the expression level of CCL5 is markedly increased in MKs. Ligand-receptor analysis reveals dynamic interactions among MKs and T cells, B cells, natural killer cells, monocytes, and macrophages, suggesting a broad role of MKs in immune homeostasis. In PICS model mice, MKs regulate systemic inflammation by reducing the levels of the proinflammatory cytokines TNF-α and IL-17A and promoting lung tissue repair. Our findings establish MKs as essential components of the immune system in PICS and provide new insights into their potential as therapeutic targets for post-sepsis immune dysfunction.

Background: Neonatal sepsis remains a leading cause of infant mortality and is driven in part by the functional immaturity of the hematopoietic system. During early postnatal life, hematopoietic stem cells (HSCs) undergo dynamic changes in self-renewal, quiescence, lineage output, and inflammatory responsiveness. While adult HSCs maintain a stable and tightly regulated state, the developmental timeline by which these properties emerge remains poorly defined. A systematic understanding of HSC maturation is essential for uncovering mechanisms of neonatal immune vulnerability and informing strategies to enhance early-life hematopoietic resilience. Results: Bone marrow hematopoietic composition across postnatal weeks 1, 2, and adulthood was examined under steady-state conditions. Frequencies of HSCs and multipotent progenitors (MPPs) remained largely unchanged across these developmental stages, but expression of myeloid-biased markers (CD38, CD61, and CD41) was reduced on neonatal HSCs compared to adults, suggesting reduced myeloid bias in early-life HSCs. Among lineage-primed progenitors, we observed a progressive decline in the frequencies of colony-forming unit–erythroid (CFU-E), pre-colony-forming unit-erythroid (pre-CFU-E), and pre-megakaryocyte-erythroid progenitors (pre-MegE) from 1-week-old mice to adulthood, indicative of a developmental restriction in erythroid differentiation potential. Within the myeloid progenitor compartment, monocyte progenitor (MoP), granulocyte-monocyte progenitor (GMP), and granulocyte progenitor (GP) population frequencies peaked in 1-week-old mice, then decreased in 2-week-old mice and adults. At the level of mature and developing neutrophils, the frequencies of mature and immature neutrophils increased progressively with age, while early neutrophil precursors (pre-neutrophils and pro-neutrophils) remained consistent across developmental stages. Competitive transplantation assays showed that HSCs from embryonic day 18 (E18) and 2-week-old mice had higher engraftment potential compared to adults, while cell cycle profiling demonstrated that HSCs achieve adult-like quiescence by week 1, indicating that acquisition of quiescence precedes the decrease of engraftment potential. In the context of infection, our preliminary findings in a neonatal mouse model of Group B Streptococcus (GBS), a major cause of sepsis and neutropenia in neonates, recapitulate this defect, suggesting that failure to initiate emergency myelopoiesis may cause early-life susceptibility to bacterial infection. Conclusion: Our study defines the postnatal timeline of hematopoietic stem and progenitor cell maturation in the bone marrow and reveals that adult-like properties emerge asynchronously. HSCs acquire adult-like quiescence status by postnatal week 1, a timepoint marked by elevated frequencies of multiple progenitor populations and increased mature myeloid output. In a neonatal GBS infection model, 1-week-old mice fail to mount emergency myelopoiesis, indicating that HSCs at this stage remain functionally immature in their response to inflammatory stress. Engraftment potential declines even later, with HSCs from E18 and 2-week-old mice retaining higher donor-derived peripheral blood reconstitution capacity than adult HSCs following transplantation. These findings support a model in which hematopoietic maturation follows a phased progression, rather than a coordinated transition, toward adult-like function. Together, this developmental framework provides new insight into early-life immune vulnerability and informs strategies to enhance neonatal hematopoietic resilience.

Abstract Introduction Hematopoiesis follows a hierarchical differentiation process that begins with hematopoietic stem and progenitor cells (HSPC). This cascade culminates in the generation of erythroid, myeloid, and lymphoid lineages. Under pathological conditions, lineage commitment can be altered, and these changes are currently poorly understood in the setting of burn injury. This study seeks to provide a more comprehensive characterization of circulating HSPC in individuals who have sustained burn injuries with respect to burn size and the occurrence of sepsis. Methods Flow Cytometry was utilized to analyze blood samples. Gating was performed with lineage markers CD3, CD14, CD19, CD41, CD56, and CD66c to determine all live, lineage-negative populations. Further gating was performed with markers CD34, CD38, CD45RA, CD49f, and CD135 to determine HSPC subpopulations. Patients were categorized into two groups based on the extent of their burn injuries: "Large" burns (>20% Total Body Surface Area or TBSA) and "Small" burns ( < 20% TBSA). They were also categorized into "Non-Septic" and "Septic" groups depending on whether they had negative (-) or positive (+) results in their blood cultures. To compare demographic, burn-related, and clinical data among these groups, statistical tests including the Student t-test, Fisher exact test, and Wilcoxon rank-sum test were employed as appropriate. HSPC event counts and frequencies were analyzed using standard flow cytometry software. Results A total of 14 patients were included in this study, 50% of which sustained Large burns of TBSA >20%. The entire cohort had a mean age of 49.4 + 14.6 years, with a greater proportion of males (71.4%) and those identifying as non-white (71.4%). During the first 72 hours after injury, absolute HSPC frequencies were largely similar between Small and Large Burn cohorts (Table 1). Among the Large Burn cohort, relative frequency of common progenitors differed when comparing Non-Septic and Septic cohorts. Those developing sepsis experienced megakaryocyte and myeloid progenitor expansion, with a corresponding reduction in lymphoid progenitors (Figure 1). Conclusions During the first 72 hours following injury, absolute HSPC frequencies appear to be largely similar when comparing small and large burns. However, when burn injury exceeds 20% TBSA, relative frequencies of common progenitors differ when comparing Non-Septic and Septic patients. Those who go on to develop sepsis display a predominance of megakaryocyte and myeloid progenitors; these patients also demonstrate a shift away from lymphopoiesis. These findings suggest that HSPC lineage commitment is pathologically altered in a subset of large burns, and the observed derangements correlate with the development of sepsis. Applicability of Research to Practice Understanding the immunological derangements that occur in burn and sepsis can lead to targeted therapies that can drive the immune system in a more favorable direction.

Background Sepsis-associated thrombocytopenia (SAT) is a common complication in critically ill patients and is associated with increased disease severity and adverse outcomes. Platelet transfusion is the main supportive therapy but provides limited and transient benefit. Evidence regarding thrombopoietin-receptor agonists in SAT remains scarce. Objectives To evaluate the association between avatrombopag administration and platelet recovery, clinical outcomes, and safety in critically ill patients with SAT. Methods We conducted a single-center, retrospective observational cohort study of adult ICU patients with SAT between May 2022 and May 2024. Patients were categorized according to avatrombopag exposure during the ICU stay. The primary outcome was platelet recovery at day 14. Secondary outcomes included platelet recovery at days 7 and 10, 28-day mortality, and ICU length of stay. Confounding was addressed using propensity score–based inverse probability of treatment weighting (IPTW). Associations were assessed using weighted regression models, with prespecified sensitivity and subgroup analyses. Results Among 256 included patients, 119 received avatrombopag and 137 did not. After IPTW adjustment, avatrombopag use was independently associated with higher odds of platelet recovery at day 14 (odds ratio 3.58, 95% confidence interval 1.31-9.79). No consistent benefit was observed for early platelet recovery at day 7 or day 10. Avatrombopag use was not associated with reduced 28-day mortality. Rates of bleeding and thrombotic events were similar between groups. However, avatrombopag exposure was consistently associated with a longer ICU length of stay. Subgroup analyses suggested greater platelet recovery benefit in patients with higher platelet transfusion requirements and greater illness severity. Conclusions In critically ill patients with SAT, avatrombopag administration was associated with improved delayed platelet recovery without increased bleeding or thrombotic risk. This hematologic benefit did not translate into improved short-term survival and was accompanied by prolonged ICU stay.

Background: Thrombocytopenia (platelet count < 100 × 109/L) occurs in 20–40% of critically ill patients with sepsis and is associated with adverse outcomes. Most prior studies have treated thrombocytopenia as a static risk indicator rather than a dynamic process. We investigated whether platelet recovery within 7 days provides independent prognostic information in patients with sepsis. Methods: We performed a retrospective cohort study using the MIMIC-IV database. Among 22,513 adults with sepsis admitted to intensive care units, 5401 developed thrombocytopenia within 24 h of admission and had sufficient follow-up data. The primary exposure was sustained platelet recovery to ≥100 × 109/L within 7 days. The primary outcomes were 28-day and in-hospital mortality. Propensity-score matching and overlap weighting were used to adjust for demographic characteristics, comorbid conditions, illness severity, and organ-support therapies. Results: Among 5401 septic ICU patients with thrombocytopenia, 3193 (59%) achieved platelet recovery within 7 days. A total of 2056 patients (38%) recovered by day 3, and 1137 (21%) recovered between days 4 and 7. After multivariable adjustment, platelet recovery was independently associated with markedly lower mortality (adjusted risk ratio, 0.56; 95% CI, 0.53–0.67 for in-hospital death; and 0.60; 95% CI, 0.53–0.67 for 28-day death) and more than a doubling of survival time (adjusted ratio, 2.08; 95% CI, 1.65–2.63). Early and intermediate recovery conferred similar benefits. Higher baseline platelet counts, antiplatelet therapy, and heparin use were associated with recovery, whereas cirrhosis, greater illness severity, and continuous renal replacement therapy were associated with non-recovery. Conclusions: In patients with sepsis and thrombocytopenia, platelet recovery within 7 days was a strong and independent predictor of survival. Exploratory timing-stratified analyses yielded similar associations across subgroups. These findings support platelet recovery as a useful prognostic marker reflecting broader physiologic stabilization in sepsis.

Introduction . Early recognition of variants of clinical manifestations of sepsis is essential for the correct choice of strategy and tactics of its treatment. The objective was to analyze the causes and manifestations of various variants of the course of sepsis and to assess the dependence of its outcomes on these factors. Materials and methods . A retrospective analysis of 189 medical records of patients with sepsis was conducted. Clinical recovery within 14 days occurred in 63 of them (group 1), and death – in 46 (group 2). 80 patients developed a chronic critical illness (CCI, group 3), which resulted in recovery in 23 cases and death in 57 cases. Demographic and anthropometric parameters, reasons for hospitalization, severity and type of comorbidities, manifestations of organ dysfunction (SOFA), source of infection, microbiological test results, and laboratory data were assessed. The neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), NLPR index (NLR x platelets), aggregate index of systemic inflammation (AISI: neutrophils x monocytes x platelets/lymphocytes), and multi-inflammatory index (MII-1: NLR x CRP, g/L) were calculated at admission and over time. ROC analysis and multivariate logistic regression analysis were used to assess the relationship between sepsis outcomes and the initial values of these factors and the rate of their change during observation and treatment. Results . No significant differences were found between the groups in initial clinical and laboratory parameters. Differences in the dynamics of sepsis progression became apparent within the first few days after the start of treatment. Despite the predictable changes in both laboratory data and composite indices corresponding to the severity of sepsis manifestations, no significant association was established between changes in most of them and the trajectory of the septic process. It was only established that ΔCRP values can predict early recovery, and the NLPR index on day 4 can predict mortality. Simultaneous use of several indices demonstrated their association with outcome more clearly (CRP + NLPR + Δ lactate for rapid recovery; CRP + NLR + AISI for early death; NLR + ΔTLR for CCI). Conclusion . Recognizing sepsis progression variants at the onset of the disease is impossible due to the lack of a significant correlation between simple clinical and laboratory parameters and outcomes. Differences in sepsis dynamics become clearly evident by the fourth day of treatment. Lymphocyte and platelet levels, CRP, procalcitonin, as well as the NLR, TLR, NLPR, MII-1, and AISI indices and their rate of change over time, are not suitable for predicting all sepsis progression variants due to their low specificity and sensitivity; the significance of each can change dramatically depending on the specific clinical scenario.

Abstract Introduction: Thrombocytopenia is considered as one of the signs of sepsis but, Changes in number, morphology and volume of platelets is not widely researched upon in this matter. Therefore, the current study is aiming to analyze the changes in number, morphology and volume of platelets during neonatal sepsis. Method: This cross-sectional study has been carried out on 807 premature neonates suspected to have infection in Ghaem hospital Mashhad from 2015-2023 by using available sampling method. The data collection tool, researcher- made checklist included laboratory evaluations by which platelet indicators {Platelet count, Platelet distribution width (PDW) and mean platelet volume (MPV)} were measured and compared before, during infection and after recovery. Afterwards, platelet characteristics in septic neonates (Case group) were compared to neonates without definite signs of infection (Control group). Results: Two hundred ninety-five neonates (35.5%) had definitive sepsis. In the case group the number of platelets was less and the amount of MPV and PDW were higher than control group. The number of platelets decreases during infection, but this numbers increase after recovery. PDW increases during infection and after recovery. Fifty four percent of infected neonates had thrombocytopenia.Thrombocytopenia in 78% of neonates with sepsis caused by klebsiella pneumoniae and in 58% of the cases caused Enterobacter aerogenes was seen. The optimal cutoff value of platelet to differentiate case from those of control group was lower than 100000/mcL, with a sensitivity of 73%, specificity 12.2% (AUC=0.427), MPV more than 9.8(Fl), with a sensitivity of 80%, specificity 47% (AUC=0.618), PDW more than 11.2(Fl), with a sensitivity of 90%, specificity 28.4% (AUC=0.763). Conclusion:During infection the number of platelets decreases, but MPV and PDW increase. Thrombocytopenia was seen more in Gram-negative bacteria rather than Gram-positive. During infection the number of platelets decreases but after recovery the number of platelets, MPV and PDW increases. Platelet indices have good sensitivity but low specificity in diagnosing definitive infection.

This retrospective cohort study aimed to evaluate the effects of continuous intravenous heparin on coagulation dysfunction, organ failure, and clinical outcomes in sepsis patients. Data from sepsis patients admitted to the ICU of Hebei University Affiliated Hospital (2017–2023) were analyzed, comparing a heparin group (initial dose: 5 U/kg/h, with dosage adjustments targeting an APTT maintained at 1.0-1.5 times the normal value) with a control group receiving prophylactic subcutaneous low-molecular-weight heparin. Outcomes included platelet count, DIC score, SOFA score, 28-day mortality, and bleeding risk, assessed daily from admission to day 7. At baseline, both groups showed comparable platelet counts, DIC scores, and SOFA scores. By day 3, the heparin group exhibited significantly higher platelet counts than controls (p<0.05), a trend sustained through day 7. DIC scores in the heparin group became significantly lower than controls from day 4 onward (p<0.05). Similarly, SOFA scores in the heparin group were notably reduced compared to controls from day 5 to day 7 (p<0.05). However, no significant differences were observed in 28-day mortality (p>0.05) or bleeding risk between groups. The findings suggest that continuous intravenous heparin improves coagulation dysfunction (reflected by platelet recovery and reduced DIC scores) and mitigates organ failure (evidenced by lower SOFA scores) in sepsis patients. Despite these benefits, heparin did not reduce 28-day mortality. The study highlights heparin’s potential role in managing sepsis-related complications but underscores the need for further research to optimize therapeutic strategies for mortality reduction.

Introduction. Romiplostim is an analogue of the fusion protein peptide of thrombopoietin (TPO), which increases platelet count by binding and activating the human thrombopoietin receptor (TPO-R). It is used to treat thrombocytopenia associated with chronic immune thrombocytopenia. For romiplostim, one of the possible adverse reactions from the immune system is immunogenicity: the production of anti-drug antibodies to the medicinal product, including neutralising antibodies, which may affect the efficacy and safety profile of the medicinal product.Aim. Validate the procedure for determining neutralising antibodies to romiplostim in human plasma for further clinical studies of immunogenicity.Materials and methods. The study used rabbit polyclonal antibodies to romiplostim, Nplate® produced by Amgen Europe as a standard sample; a placebo produced by LLC "GEROPHARM", a cell line 32D-hTPOR clone 63 with stable expression of human TPO receptor and a chemiluminescence assay kit CellTiter-Glo® Luminescent Cell Viability Assay produced by Promega to assess specificity. The experiment was carried out on cell line 32D-hTPOR clone 63, which was seeded on the first day and the neutralizing antibody concentrations were titrated with a constant concentration of romiplostim, then the chemiluminescence was detected on the second day. Statistical processing of the results was carried out using Prism 9 software.Result and discussion. The specificity of the procedure was demonstrated; at maximum concentration, the medicinal product differs from placebo by 309 times in the residual level of cell viability. The linearity of the procedure in terms of the coefficient determination is 0.9969. The precision of the procedure was determined: the repeatability was 1–9 %, the intermediate precision was 3–18 %. The coefficient of variation in selectivity of the procedure was 22 %. For the accuracy parameter, the values for recovery/spike were determined as 90–101 %. It was proven that there was no matrix effect.Conclusion. It can be stated that the procedure is linear, specific, highly precise, correct, selective and with a proven absence of matrix effect, which allows it to be used to determine the immunogenicity of romiplostim medicinal products in clinical studies.

Recent developments in proteomics suggest opportunities to understand the pathophysiological heterogeneity of sepsis and provide precision medicine tailored to individual patients. This study aims to evaluate the serum proteomic profiles of patients with sepsis using Sequential Window Acquisition of All Theoretical Mass Spectra proteomics and identify novel biomarkers for assessing sepsis severity and predicting patient outcomes in the ICU. This retrospective cohort study included 217 adult patients diagnosed with bacterial sepsis who were admitted to a medical ICU at a single tertiary hospital between January 2011 and January 2020, along with 292 healthy controls. Proteomic analysis was performed to compare patients with sepsis to the 292 healthy controls and analyze differences among sepsis subgroups. The subgroups were classified according to their outcome: early death (within 3 days), late death (after 3 days), and recovery (survived and discharged). Five key proteins—β-actin (ACTB), fibronectin (FINC), metalloproteinase inhibitor 1 (TIMP1), platelet factor 4 (PF4), and C-X-C motif chemokine 7 (CXCL7)—were identified as significant discriminators of sepsis subgroups with AUCs ranging from 0.786 to 0.833. A six-variable model including 5 proteins and the SOFA score showed the highest AUC value of 0.903 for predicting in-hospital mortality. Multivariable Cox proportional hazards analysis revealed that increased ACTB (hazard ratio [HR] 1.21 [1.07–1.36], p = 0.002), decreased FINC (HR 0.88 [0.79–0.98], p = 0.024), higher SOFA scores (HR 1.08 [1.03–1.13], p = 0.002) and gram-negative sepsis (HR 1.42 [1.02–1.97], p = 0.038) were significantly associated with increased in-hospital mortality. A novel set of biomarkers was identified in this study, including ACTB, FINC, CXCL7, TIMP1, and PF4, for assessing sepsis prognosis. The six-variable model incorporating SOFA scores demonstrated a high prognostic value for in-hospital mortality, potentially enabling more accurate risk stratification for patients with sepsis in the ICU.

Abstract In comparison to mature platelets, reticulated platelets (RPs) are newly released from the bone marrow and exhibit a larger size, higher reactivity, and a greater quantity of RNA, and can be an agile indicator of platelet turnover. The transcriptome associated with platelet function is significantly upregulated in RPs, which is a possible explanation for RPs intrinsic hyper-reactivity. We presented a comprehensive overview of the detection techniques for RPs. Current methods to quantify RPs in clinical routine are flow cytometry and fully automated hematology analyzers (Sysmex-XE/XN, Abbott, ADVIA, Mindray), which make the detection of RPs simpler, faster and more affordable. The proportion of RPs increased in the circulation has potential diagnostic and prognostic values in multiple clinical settings (risk stratification in cardiovascular diseases, the effect on antiplatelet drugs, differential diagnosis of thrombocytopenia, monitor platelet recovery after bone marrow or stem cell transplantation, and other diseases). There have been several studies focusing on RPs in recent years, particularly in cardiovascular disease and thrombocytopenia. In this review we summarizes the current study with regard to RPs and discuss their likely contribution in clinical routine. Plain Language Summary This review seeks to provide an overview of the key features of RPs which are quite different from mature platelets. RPs have been associated with cardiovascular disease and antiplatelet therapy. Transcriptomic analyses of RPs suggest that elevated protein levels involved in platelet activation may enhance thrombosis. We provide an outline of available technology for measuring immature or reticulated platelets and try to establish reference intervals for IPF. According to the former researches, IPF have shown utility in non-cardiovascular diseases (such as thrombocytopenia, sepsis, post-chemotherapy or stem cell transplantation, 2019 coronavirus disease, eclampsia, liver disease, and thrombocythemia) and cardiovascular diseases in particular. The focus on RPs research might improve the treatment of patients.

OBJECTIVE To investigate whether bone marrow mesenchymal stem cells derived exosomes (BMSCs-exo) can alleviate sepsis-induced lung injury and its related mechanism by inhibiting ferroptosis of macrophages. METHODS RAW264.7 cells were first stimulated with lipopolysaccharide (LPS) to observe whether macrophage ferroptosis occurred. After pre-treating BMSCs with the exosome inhibitor GW4869, the lung-protective effect was observed to determine if it was eliminated. Furthermore, BMSCs-exo was extracted to clarify if it could exert effects like BMSCs. Finally, key molecules responsible for the effects were identified through sequencing and other related techniques. RESULTS Following stimulation with LPS, the expression of GPX4 in RAW264.7 cells decreased significantly, while the expression of PTGS2 increased significantly. The intracellular GSH content decreased, while MDA content increased. BMSCs-exo reversed the decrease in GPX4 and increase in PTGS2, increased GSH and decreased MDA. Sequencing revealed that lncRNA SNHG12 in macrophages was significantly upregulated after co-culture with BMSCs-exo. Knockdown of lncRNA SNHG12 in BMSCs via siRNA resulted in a significant decrease in the inhibitory effect on macrophage ferroptosis both in vivo and in vitro. CONCLUSION BMSCs-exo can inhibit macrophage ferroptosis through lncRNA SNHG12, thereby alleviating the sepsis-induced lung injury and improving the survival rate.

Sepsis-associated encephalopathy (SAE) is one of the most common and severe complications of sepsis. Although lactate and neutrophils play pivotal roles in SAE, the mechanisms linking lactate, neutrophils, and neuroinflammation in SAE remain largely unclear. In this study, SAE model was induced in C57BL/6 J mice via intraperitoneal lipopolysaccharide (LPS) injection, with lactate production inhibited by administering the lactate dehydrogenase inhibitor FX-11. Neutrophils were visualized by immunofluorescence, and immune cell subsets were quantified via flow cytometry. Our findings revealed that lactate levels in the skull bone marrow (SBM) were significantly elevated in SAE mice, accompanied by decreased SBM neutrophils and increased neutrophil extravasation into the meninges. These effects were reproduced in exogenous lactate-administered normal mice. Further studies identified that a CD31+ channel between the SBM and meninges facilitates neutrophil mobilization and migration. Notably, FX-11 injection significantly alleviated SAE in mice, as indicated by reduced SBM lactate production, inhibited neutrophil mobilization, decreased meningeal neutrophil extravasation, suppressed microglial activation and reduced hippocampal inflammatory cytokines as well. In summary, our results show that elevated lactate levels in the SBM promote neutrophil migration between the skull and meninges and hence exacerbate SAE neuroinflammation, which can be potently improved in the presence of the lactate inhibitor FX-11. The migration of neutrophils influenced by lactate in the skull-meninges-brain axis could be a potential therapeutic target for the treatment of SAE.

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Plasmacytoid dendritic cells (pDCs) are crucial components of the immune response during viral infections, yet their function and development in the late phase of sepsis remain poorly understood. In this study, we investigated the impact of prolonged sepsis on pDCs and their progenitors in cecal ligation and puncture (CLP)-induced septic mice. We observed a significant reduction in both pDCs and their progenitors, alongside the presence of mature and regulatory pDCs. These mature and regulatory pDCs exhibited impaired type I interferon (IFN) secretion and antigen presentation capacity. In a Flt3L culture system of hematopoietic stem/progenitor cells (HSPCs) from CLP and Sham mice, we found that CLP-derived HSPCs exhibited an impaired ability to generate immunocompetent pDCs, as evidenced by lower IFN-α expression and reduced pDC recovery. Further investigation revealed downregulation of the key transcription factor TCF4 during pDC differentiation in these progenitor cells. Ectopic expression of TCF4 in these progenitors restored pDC generation. Additionally, we observed elevated levels of granulocyte colony-stimulating factor (G-CSF) in the bone marrow supernatant of septic mice. The addition of G-CSF to the culture system significantly impaired the generation of immunocompetent pDCs from HSPCs of normal mice. These findings suggest that sepsis may impair the production of immunocompetent pDCs from HSPCs by modulating key genes involved in pDC differentiation, potentially contributing to immune suppression and increased susceptibility to opportunistic infections in the later stages of sepsis.

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Sepsis is a condition with high mortality and morbidity, characterized by deregulation of the immune response against the pathogen. Current treatment strategies rely mainly on antibiotics and supportive care. However, there is growing interest in exploring cell-based therapies as complementary approaches. Human liver stem cells (HLSCs) are pluripotent cells of mesenchymal origin, showing some advantages compared to mesenchymal stem cells in terms of immunomodulatory properties. HSLC-derived extracellular vesicles (EVs) exhibited a superior efficacy profile compared to cells due to their potential to get through biological barriers and possibly to avoid tumorigenicity and showed to be effective in vivo and ex vivo models of liver and kidney disease. The potential of HLSCs and their EVs in recovering damage to distal organs due to sepsis other than the kidney remains unknown. This study aimed to investigate the therapeutic potential of the intravenous administration of HSLCs or HSLCs-derived EVs in a murine model of sepsis. Sepsis was induced by caecal ligation and puncture (CLP) on C57/BL6 mice. After CLP, mice were assigned to receive either normal saline, HLSCs or their EVs and compared to a sham group which underwent only laparotomy. Survival, persistence of bacteraemia, lung function evaluation, histology and bone marrow analysis were performed. Administration of HLSCs or HLSC-EVs resulted in improved bacterial clearance and lung function in terms of lung elastance and oedema. Naïve murine hematopoietic progenitors in bone marrow were enhanced after treatment as well. Administration of HLSCs and HLSC-EVs after CLP to significantly improved survival. Treatment with HLSCs or HLSC-derived EVs was effective in improving acute lung injury, dysmyelopoiesis and ultimately survival in this experimental murine model of lethal sepsis.

Humanized MISTRG6 mice reveal early bone marrow remodeling in CLP sepsis, including altered HSPC dynamics and niche composition. This model is highly translational for studying human hematopoiesis and therapeutic interventions after CLP.

BACKGROUND Sepsis is a severe illness characterized by systemic and multiorgan reactive responses and damage. However, the impact of sepsis on the bone marrow, particularly on bone marrow mesenchymal stem cells (BMSCs), is less reported. BMSCs are critical stromal cells in the bone marrow microenvironment that maintain bone stability and hematopoietic homeostasis; however, the impairment caused by sepsis remains unknown. AIM To investigate the effects of sepsis on BMSCs and the underlying mechanisms. METHODS BMSCs were obtained from healthy donors and patients with sepsis. We compared the self-renewal capacity, differentiation potential, and hematopoietic supportive ability in vitro. Senescence of septic BMSCs was assessed using β-galactosidase staining, senescence-associated secretory phenotype, intracellular reactive oxygen species levels, and the expression of P16 and P21. Finally, the changes in septic BMSCs after nicotinamide adenine dinucleotide (NAD) treatment were evaluated. RESULTS Septic BMSCs showed decreased proliferation and self-renewal, bias towards adipogenic differentiation, and weakened osteogenic differentiation. Additionally, hematopoietic supportive capacity declines in sepsis. The levels of aging markers were significantly higher in the septic BMSCs. After NAD treatment, the proliferation capacity of septic BMSCs showed a recovery trend, with increased osteogenic and hematopoietic supportive capacities. Sepsis resulted in decreased expression of sirtuin 3 (SIRT3) in BMSCs, whereas NAD treatment restored SIRT3 expression, enhanced superoxide dismutase enzyme activity, reduced intracellular reactive oxygen species levels, maintained mitochondrial stability and function, and ultimately rejuvenated septic BMSCs. CONCLUSION Sepsis accelerates the aging of BMSCs, as evidenced by a decline in self-renewal and osteogenic capabilities, as well as weakened hematopoietic support functions. These deficiencies can be effectively reversed via the NAD/SIRT3/superoxide dismutase pathway.

Blood‐borne pathogen (BBP) infections can rapidly progress to life‐threatening sepsis and must therefore be promptly eliminated by the host's immune system. Intravascular macrophages of the liver sinusoid, splenic marginal zone and red pulp and perisinusoidal macrophage protrusions in the bone marrow (BM) directly phagocytose BBPs in the blood as an innate immune response. The liver, spleen and BM thereby work together as the blood defence system (BDS) in response to BBPs by exerting their different immunological roles. The liver removes the vast majority of these invading organisms via innate immunity, but their complete elimination is not possible without the actions of antibodies. Splenic marginal zone B cells promptly produce IgM and IgG antibodies against BBPs. The splenic marginal zone transports antigenic information from the innate to the adaptive immune systems. The white pulp of the spleen functions as adaptive immune tissue and produces specific and high‐affinity antibodies with an immune memory against BBPs. The BM works to maintain immune memory by supporting the survival of memory B cells, memory T cells and long‐lived plasma cells (LLPCs), all of which have dedicated niches. Furthermore, BM perisinusoidal naïve follicular B cells promptly produce IgM antibodies against BBPs in the BM sinusoid and the IgG memory B cells residing in the BM rapidly transform to plasma cells which produce high‐affinity IgG antibodies upon reinfection. This review describes the complete immune defence characteristics of the BDS against BBPs through the collaboration of the liver, spleen and BM with combined different immunological roles.

Early increase in the level of endothelial progenitor cells (EPCs) in the systemic circulation occurs in patients with septic infection/sepsis. The significance and underlying mechanisms of this response remain unclear. This study investigated the bone marrow EPC response in adult mice with septic infection induced by intravenous injection (i.v.) of Escherichia coli. For in vitro experiments, sorted marrow stem/progenitor cells (SPCs) including lineage(lin)-stem cell factor receptor (c-kit)+stem cell antigen-1 (Sca-1)−, lin−c-kit+, and lin− cells were cultured with or without lipopolysaccharides (LPSs) and recombinant murine vascular endothelial growth factor (VEGF) in the absence and presence of anti-Sca-1 crosslinking antibodies. In a separate set of experiments, marrow lin−c-kit+ cells from green fluorescence protein (GFP)+ mice, i.v. challenged with heat-inactivated E. coli or saline for 24 h, were subcutaneously implanted in Matrigel plugs for 5 weeks. Marrow lin−c-kit+ cells from Sca-1 knockout (KO) mice challenged with heat-inactivated E. coli for 24 h were cultured in the Matrigel medium for 8 weeks. The marrow pool of EPCs bearing the lin−c-kit+Sca-1+VEGF receptor 2 (VEGFR2)+ (LKS VEGFR2+) and LKS CD133+VEGFR2+ surface markers expanded rapidly following septic infection, which was supported by both proliferative activation and phenotypic conversion of marrow stem/progenitor cells. Increase in marrow EPCs and their reprogramming for enhancing angiogenic activity correlated with cell-marked upregulation of Sca-1 expression. Sca-1 was coupled with Ras-related C3 botulinum toxin substrate 2 (Rac2) in signaling the marrow EPC response. Septic infection caused a substantial increase in plasma levels of IFN-γ, VEGF, G-CSF, and SDF-1. The early increase in circulating EPCs was accompanied by their active homing and incorporation into pulmonary microvasculature. These results demonstrate that the marrow EPC response is a critical component of the host defense system. Sca-1 signaling plays a pivotal role in the regulation of EPC response in mice with septic infection.

Abstract Objectives A nuclear detonation resulting in radiation exposure to a large population can cause acute radiation syndrome (ARS). Bone marrow colony stimulating factors (CSF), also known as cytokines, are FDA approved to treat hematopoietic-acute radiation syndrome (H-ARS). This review characterizes the use of CSFs (filgrastim, pegfilgrastim, romiplostim, and sargramostim) and stem cell therapies for H-ARS. Methods Using identified keywords, the literature search was conducted on biomedical databases from January 1996-July 2022 and returned 7452 articles. However, after review based on PICO and exclusion criteria, a total of 39 animal studies were included in this systematic review. Results Data synthesis using vote counting demonstrated that 34 of 39 studies reported benefit with CSFs or stem cell therapies based on an increase in percent survival or physiological improvement in the experimental group when compared to the control (87% [95% CI 71.77%-95.18%], P = <0.001). Conclusions While studies looking at efficacy of CSFs given after 24 hours were limited, 2 studies included in this review showed that delayed administration of CSFs up to 120 hours may be beneficial compared to no treatment. Lack of standardization in experimental study design (e.g. radiation doses, animal species, interventions) between studies prevented direct comparisons using meta-analytic statistical approach.

Platelets are short-lived anucleate cells essential for primary hemostasis and recognized for their functions in thrombosis, immunity, antimicrobial defense, neurodegeneration, as well as cancer growth and metastasis. Their brief lifespan in circulation is controlled by the removal of sialic acid residues from the platelet surface (desialylation) and also the mitochondrial apoptosis pathway, with high expression of the anti-apoptotic protein BCL-XL being required for platelet survival. This dependence on BCL-XL has prevented the clinical deployment of recently developed small molecule inhibitors of BCL-XL, which have promising activity in solid as well as liquid cancers but cause on-target thrombocytopenia. Here, we investigate the functional relationship between platelet desialylation and apoptosis to determine how cross-talk between these mechanisms may impact platelet lifespan. We find that platelets progressively lose sialic acid residues and become more primed for apoptosis while in circulation, resulting in aged platelets that are desialylated and highly prone to undergoing apoptosis. In addition, platelet desialylation via endogenous or exogenous factors directly increases their BCL-XL dependence and accelerates apoptosis, which can be reversed by treatment with the sialidase inhibitor DANA (2,3-dehydro-2-deoxy-N-acetylneuraminic acid). Notably, young platelets recently released into circulation are less primed for apoptosis and less dependent on BCL-XL for survival. Consistent with these changes in priming, platelets aged in vitro exhibit increasing expression of multiple pro-apoptotic proteins including BIM, BAK and PUMA along with increasing cleaved caspase 3. Leveraging the lower BCL-XL dependence of young platelets, stimulation of de novo platelet production with the thrombopoietin receptor agonist romiplostim prevents BH3 mimetic-induced thrombocytopenia in vivo and may prevent severe platelet loss in patients treated with BCL-XL inhibitors.

Background: The search for new biomarkers that allow an early diagnosis in sepsis has become a necessity in medicine. The objective of this study is to identify potential protein biomarkers of differential expression between sepsis and non-infectious systemic inflammatory response syndrome (NISIRS). Methods: Prospective observational study of a cohort of septic patients activated by the Sepsis Code and patients admitted with NISIRS, during the period 2016-2017. A mass spectrometry-based approach was used to analyze the plasma proteins in the enrolled subjects. Subsequently, using recursive feature elimination (RFE) classification and cross-validation with a vector classifier, an association of these proteins in patients with sepsis compared to patients with NISIRS. The protein-protein interaction network was analyzed with String software. Results: A total of 277 patients (141 with sepsis and 136 with NISIRS) were included. After performing RFE, 25 proteins in the study patient cohort showed statistical significance, with an accuracy of 0.960, specificity of 0.920, sensitivity of 0.973, and an AUC of 0.985. Of these, 14 proteins (vWF, PPBP, C5, C1RL, FCN3, SAA2, ORM1, ITIH3, GSN, C1QA, CA1, CFB, C3, LBP) have a greater relationship with sepsis while 11 proteins (FN1, IGFALS, SERPINA4, APOE, APOH, C6, SERPINA3, AHSG, LUM, ITIH2, SAA1) are more expressed in NISIRS.

Sepsis is a life threatening condition that requires timely detection in intensive care settings. Traditional machine learning approaches, including Naive Bayes, Support Vector Machine (SVM), Random Forest, and XGBoost, often rely on manual feature engineering and struggle with irregular, incomplete time-series data commonly present in electronic health records. We introduce an end-to-end deep learning framework integrating an unsupervised autoencoder for automatic feature extraction with a multilayer perceptron classifier for binary sepsis risk prediction. To enhance clinical applicability, we implement a customized down sampling strategy that extracts high information density segments during training and a non-overlapping dynamic sliding window mechanism for real-time inference. Preprocessed time series data are represented as fixed dimension vectors with explicit missingness indicators, mitigating bias and noise. We validate our approach on three ICU cohorts. Our end-to-end model achieves accuracies of 74.6 percent, 80.6 percent, and 93.5 percent, respectively, consistently outperforming traditional machine learning baselines. These results demonstrate the framework's superior robustness, generalizability, and clinical utility for early sepsis detection across heterogeneous ICU environments.

Objective: Sepsis is a life-threatening condition caused by severe infection leading to acute organ dysfunction. This study proposes a data-driven metric and a continuous reward function to optimize personalized heparin therapy in surgical sepsis patients. Methods: Data from the MIMIC-IV v1.0 and eICU v2.0 databases were used for model development and evaluation. The training cohort consisted of abdominal surgery patients receiving unfractionated heparin (UFH) after postoperative sepsis onset. We introduce a new RL-based framework: converting the discrete SOFA score to a continuous cxSOFA for more nuanced state and reward functions; Second, defining "good" or "bad" strategies based on cxSOFA by a stepwise manner; Third, proposing a Treatment Effect Comparison Matrix (TECM), analogous to a confusion matrix for classification tasks, to evaluate the treatment strategies. We applied different RL algorithms, Q-Learning, DQN, DDQN, BCQ and CQL to optimize the treatment and comprehensively evaluated the framework. Results: Among the AI-derived strategies, the cxSOFA-CQL model achieved the best performance, reducing mortality from 1.83% to 0.74% with the average hospital stay from 11.11 to 9.42 days. TECM demonstrated consistent outcomes across models, highlighting robustness. Conclusion: The proposed RL framework enables interpretable and robust optimization of heparin therapy in surgical sepsis. Continuous cxSOFA scoring and TECM-based evaluation provide nuanced treatment assessment, showing promise for improving clinical outcomes and decision-support reliability.

The early and accurate diagnosis of sepsis is critical for enhancing patient outcomes. This study aims to use heart rate variability (HRV) features to develop an effective predictive model for sepsis detection. Critical HRV features are identified through feature engineering methods, including statistical bootstrapping and the Boruta algorithm, after which XGBoost and Random Forest classifiers are trained with differential hyperparameter settings. In addition, ensemble models are constructed to pool the prediction probabilities of high-recall and high-precision classifiers and improve model performance. Finally, a neural network model is trained on the HRV features, achieving an F1 score of 0.805, a precision of 0.851, and a recall of 0.763. The best-performing machine learning model is compared to this neural network through an interpretability analysis, where Local Interpretable Model-agnostic Explanations are implemented to determine decision-making criterion based on numerical ranges and thresholds for specific features. This study not only highlights the efficacy of HRV in automated sepsis diagnosis but also increases the transparency of black box outputs, maximizing clinical applicability.

Background and Objectives: We aim to establish deep learning models to optimize the individualized energy delivery for septic patients. Methods and Study Design: We conducted a study of adult septic patients in Intensive Care Unit (ICU), collecting 47 indicators for 14 days. After data cleaning and preprocessing, we used stats to explore energy delivery in deceased and surviving patients. We filtered out nutrition-related features and divided the data into three metabolic phases: acute early, acute late, and rehabilitation. Models were built using data before September 2020 and validated on the rest. We then established optimal energy target models for each phase using deep learning. Results: A total of 277 patients and 3115 data were included in this study. The models indicated that the optimal energy targets in the three phases were 900kcal/d, 2300kcal/d, and 2000kcal/d, respectively. Excessive energy intake increased mortality rapidly in the early period of the acute phase. Insufficient energy in the late period of the acute phase significantly raised the mortality of septic patients. For the rehabilitation phase, too much or too little energy delivery both associated with high mortality. Conclusion: Our study established time-series prediction models for septic patients to optimize energy delivery in the ICU. This approach indicated the feasibility of developing nutritional tools for critically ill patients. We recommended permissive underfeeding only in the early acute phase. Later, increased energy intake may improve survival and settle energy debts caused by underfeeding.

Sepsis is a life-threatening condition defined by end-organ dysfunction due to a dysregulated host response to infection. Although the Surviving Sepsis Campaign has launched and has been releasing sepsis treatment guidelines to unify and normalize the care for sepsis patients, it has been reported in numerous studies that disparities in care exist across the trajectory of patient stay in the emergency department and intensive care unit. Here, we apply a number of reinforcement learning techniques including behavioral cloning, imitation learning, and inverse reinforcement learning, to learn the optimal policy in the management of septic patient subgroups using expert demonstrations. Then we estimate the counterfactual optimal policies by applying the model to another subset of unseen medical populations and identify the difference in cure by comparing it to the real policy. Our data comes from the sepsis cohort of MIMIC-IV and the clinical data warehouses of the Mass General Brigham healthcare system. The ultimate objective of this work is to use the optimal learned policy function to estimate the counterfactual treatment policy and identify deviations across sub-populations of interest. We hope this approach would help us identify any disparities in care and also changes in cure in response to the publication of national sepsis treatment guidelines.

Sepsis-induced acute respiratory failure (ARF) is a serious complication with a poor prognosis. This paper presents a deep representation learningbased phenotyping method to identify distinct groups of clinical trajectories of septic patients with ARF. For this retrospective study, we created a dataset from electronic medical records (EMR) consisting of data from sepsis patients admitted to medical intensive care units who required at least 24 hours of invasive mechanical ventilation at a quarternary care academic hospital in southeast USA for the years 2016-2021. A total of N=3349 patient encounters were included in this study. Clustering Representation Learning on Incomplete Time Series Data (CRLI) algorithm was applied to a parsimonious set of EMR variables in this data set. To validate the optimal number of clusters, the K-means algorithm was used in conjunction with dynamic time warping. Our model yielded four distinct patient phenotypes that were characterized as liver dysfunction/heterogeneous, hypercapnia, hypoxemia, and multiple organ dysfunction syndrome by a critical care expert. A Kaplan-Meier analysis to compare the 28-day mortality trends exhibited significant differences (p < 0.005) between the four phenotypes. The study demonstrates the utility of our deep representation learning-based approach in unraveling phenotypes that reflect the heterogeneity in sepsis-induced ARF in terms of different mortality outcomes and severity. These phenotypes might reveal important clinical insights into an effective prognosis and tailored treatment strategies.

Eligibility criteria play a critical role in clinical trials by determining the target patient population, which significantly influences the outcomes of medical interventions. However, current approaches for designing eligibility criteria have limitations to support interactive exploration of the large space of eligibility criteria. They also ignore incorporating detailed characteristics from the original electronic health record (EHR) data for criteria refinement. To address these limitations, we proposed TrialCompass, a visual analytics system integrating a novel workflow, which can empower clinicians to iteratively explore the vast space of eligibility criteria through knowledge-driven and outcome-driven approaches. TrialCompass supports history-tracking to help clinicians trace the evolution of their adjustments and decisions when exploring various forms of data (i.e., eligibility criteria, outcome metrics, and detailed characteristics of original EHR data) through these two approaches. This feature can help clinicians comprehend the impact of eligibility criteria on outcome metrics and patient characteristics, which facilitates systematic refinement of eligibility criteria. Using a real-world dataset, we demonstrated the effectiveness of TrialCompass in providing insights into designing eligibility criteria for septic shock and sepsis-associated acute kidney injury. We also discussed the research prospects of applying visual analytics to clinical trials.

Group sequential designs (GSDs) are well established and the most commonly used adaptive design in confirmatory clinical trials with interim analyses. However, they remain underutilised, and their implementation involves unique theoretical and practical decisions that demand careful consideration to optimise efficiency. A common practice is to schedule interim analyses at equal intervals based on calendar time or accumulated data. While straightforward, this approach does not completely exploit the potential sample size savings achievable with GSDs. To address this challenge, we develop OptimInterim, an R-based tool that can determine the optimal scheduling of interim analyses to minimise the expected sample size under the alternative hypothesis while controlling overall type I and type II errors. Our method accommodates trials with continuous or binary endpoints, allows multiple interim analyses and supports a range of stopping boundaries. Through extensive simulations, we demonstrate that optimally spaced interim analyses can yield substantial savings in expected sample size compared to equally spaced interim analyses, without compromising the maximum sample size, across various endpoint types, effect sizes, error rates and stopping rules. We illustrate its practical utility with two landmark trials evaluating steroid use in septic shock. Notably, for given type I and type II error rates, the optimal scheduling is independent of endpoint types and effect sizes, ensuring broad applicability across a wide range of trial contexts. To facilitate implementation, we offer a ready-to-use reference table of optimal schedules for up to eight interim analyses under commonly used error rates and stopping rules. Access OptimInterim at https://github.com/zhangyi-he/GSD_OptimInterim.

Precise classification of megakaryocytes is crucial for diagnosing myelodysplastic syndromes. Although self-supervised learning has shown promise in medical image analysis, its application to classifying megakaryocytes in stained slides faces three main challenges: (1) pervasive background noise that obscures cellular details, (2) a long-tailed distribution that limits data for rare subtypes, and (3) complex morphological variations leading to high intra-class variability. To address these issues, we propose the ActiveSSF framework, which integrates active learning with self-supervised pretraining. Specifically, our approach employs Gaussian filtering combined with K-means clustering and HSV analysis (augmented by clinical prior knowledge) for accurate region-of-interest extraction; an adaptive sample selection mechanism that dynamically adjusts similarity thresholds to mitigate class imbalance; and prototype clustering on labeled samples to overcome morphological complexity. Experimental results on clinical megakaryocyte datasets demonstrate that ActiveSSF not only achieves state-of-the-art performance but also significantly improves recognition accuracy for rare subtypes. Moreover, the integration of these advanced techniques further underscores the practical potential of ActiveSSF in clinical settings.

Thrombosis involves processes spanning large-scale fluid flow to sub-cellular events such as platelet activation. Traditional CFD approaches often treat blood as a continuum, which can limit their ability to capture these microscale phenomena. In this paper, we introduce a neural operator-based surrogate model to bridge this gap. Our approach employs DeepONet, trained on high-fidelity particle dynamics simulations performed in LAMMPS under a single shear flow condition. The model predicts both platelet membrane deformation and accumulated stress over time, achieving a mode error of ~0.3% under larger spatial filtering radii. At finer scales, the error increases, suggesting a correlation between the DeepONet architecture's capacity and the spatial resolution it can accurately learn. These findings highlight the importance of refining the trunk network to capture localized discontinuities in stress data. Potential strategies include using deeper trunk nets or alternative architectures optimized for graph-structured meshes, further improving accuracy for high-frequency features. Overall, the results demonstrate the promise of neural operator-based surrogates for multi-scale platelet modeling. By reducing computational overhead while preserving accuracy, our framework can serve as a critical component in future simulations of thrombosis and other micro-macro fluid-structure problems.

Reliable multiscale models of thrombosis require platelet-scale fidelity at organ-scale cost, a gap that scientific machine learning has the potential to narrow. We train a DeepONet surrogate on platelet dynamics generated with LAMMPS for platelets spanning ten elastic moduli and capillary numbers (0.07 - 0.77). The network takes in input the wall shear stress, bond stiffness, time, and initial particle coordinates and returns the full three-dimensional deformation of the membrane. Mean-squared-error minimization with Adam and adaptive learning-rate decay yields a median displacement error below 1%, a 90th percentile below 3%, and a worst case below 4% over the entire calibrated range while accelerating computation by four to five orders of magnitude. Leave-extremes-out retraining shows graceful extrapolation: the held-out stiffest and most compliant platelets retain sub-3% median error and an 8% maximum. Error peaks coincide with transient membrane self-contact, suggesting improvements via graph neural trunks and physics-informed torque regularization. These results classify the surrogate as high-fidelity and position it for seamless coupling with continuum CFD, enabling platelet-resolved hemodynamic simulations in patient-specific geometries and opening new avenues for predictive thrombosis modeling.

Bone marrow (BM) metabolic quantification with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is of broad clinical significance for accurate assessment of BM at staging and follow-up, especially when immunotherapy is involved. However, current methods of quantifying BM may be inaccurate because the volume defined to measure bone marrow may also consist of a fraction of trabecular bone in which 18F-FDG activity is negligible, resulting in a potential underestimation of true BM uptake. In this study, we demonstrate this bone-led tissue composition effect and propose a bone fraction correction (BFC) method using X-ray dual-energy computed tomography (DECT) material decomposition. This study included ten scans from five cancer patients who underwent baseline and follow-up dynamic 18F-FDG PET and DECT scans using the uEXPLORER total-body PET/CT system. The voxel-wise bone volume fraction was estimated from DECT and then incorporated into the PET measurement formulas for BFC. The standardized uptake value (SUV), 18F-FDG delivery rate K1, and net influx rate Ki values in BM regions were estimated with and without BFC and compared using the statistical analysis. The results first demonstrated the feasibility of performing voxel-wise material decomposition using DECT for metabolic BM imaging. With BFC, the SUV, K1, and Ki values significantly increased by an average of 13.28% in BM regions compared to those without BFC (all P<0.0001), indicating the impact of BFC for BM quantification. Parametric imaging with BFC further confirmed regional analysis. Our study using DECT suggests current SUV and kinetic quantification of BM are likely underestimated in PET due to the presence of a significant bone volume fraction. Incorporating tissue composition information through BFC may improve BM metabolic quantification.

Human bone marrow stromal cells (BMSC) include skeletal stem cells with ground-breaking therapeutic potential. However, BMSC colonies have very heterogeneous in vivo behaviour, due to their different potency; this unpredictability is the greatest hurdle to the development of skeletal regeneration therapies. Colony-level heterogeneity urges a fundamental question: how is it possible that one colony as a collective unit behaves differently from another one? If cell-to-cell variability were just an uncorrelated random process, a million cells in a transplant-bound colony would be enough to yield statistical homogeneity, hence washing out any colony-level traits. A possible answer is that the differences between two originating cells are transmitted to their progenies and collectively persist through an hereditary mechanism. But non-genetic inheritance remains an elusive notion, both at the experimental and at the theoretical level. Here, we prove that heterogeneity in the lineage topology of BMSC clonal colonies is determined by heritable traits that regulate cell-cycle exit. The cornerstone of this result is the definition of a novel entropy of the colony, which measures the hereditary ramifications in the distribution of inactive cells across different branches of the proliferation tree. We measure the entropy in 32 clonal colonies, obtained from single-cell lineage tracing experiments, and show that in the greatest majority of clones this entropy is decisively smaller than that of the corresponding non-hereditary lineage. This result indicates that hereditary epigenetic factors play a major role in determining cycle exit of bone marrow stromal cells.