Daily Sepsis Research Analysis
Top findings today span precision subphenotyping and causal biology in sepsis. A simplified bedside algorithm reliably identifies a dyslipidemic sepsis subphenotype with higher mortality, histone H3K18 lactylation in BAL fluid emerges as a promising early biomarker for sepsis-related ARDS, and Mendelian randomization implicates specific inflammatory proteins (β-NGF, VEGF-A, TRAIL) as causal determinants of sepsis risk and mortality.
Summary
Top findings today span precision subphenotyping and causal biology in sepsis. A simplified bedside algorithm reliably identifies a dyslipidemic sepsis subphenotype with higher mortality, histone H3K18 lactylation in BAL fluid emerges as a promising early biomarker for sepsis-related ARDS, and Mendelian randomization implicates specific inflammatory proteins (β-NGF, VEGF-A, TRAIL) as causal determinants of sepsis risk and mortality.
Research Themes
- Bedside subphenotyping and risk stratification in sepsis
- Epigenetic and metabolic biomarkers for sepsis-related ARDS
- Genetic causal inference of inflammatory mediators in sepsis
Selected Articles
1. IDENTIFYING A SEPSIS SUBPHENOTYPE CHARACTERIZED BY DYSREGULATED LIPOPROTEIN METABOLISM USING A SIMPLIFIED CLINICAL DATA ALGORITHM.
Using four readily available variables (hepatic SOFA, cardiovascular SOFA, LDL-C, HDL-C), the authors derived a bedside algorithm that classified sepsis patients into hypolipoprotein (higher mortality) vs normolipoprotein (lower mortality) subphenotypes with AUROC 0.86 and robust external validation. HYPO patients consistently exhibited lower LDL-C/HDL-C and higher short-term mortality.
Impact: Delivers a simple, externally validated stratification tool linking lipid metabolism to sepsis outcomes, enabling precision trial enrollment and targeted supportive strategies.
Clinical Implications: Clinicians can rapidly identify a dyslipidemic, high-risk sepsis subphenotype at the bedside to guide prognostication, nutritional/lipid monitoring, and stratified enrollment in trials of lipid-modulating or host-response therapies.
Key Findings
- Four features (hepatic SOFA, cardiovascular SOFA, LDL-C, HDL-C) discriminated HYPO vs NORMO with AUROC 0.86, sensitivity 0.771, specificity 0.779.
- HYPO patients had higher mortality: 28-day 26% vs 15% (internal); 30% vs 10% (external).
- HYPO showed lower LDL-C, HDL-C, and total cholesterol across internal and external datasets; LDL-C distributions were similar across datasets for HYPO (P=0.99).
Methodological Strengths
- External validation across three independent French cohorts
- Parsimonious model using widely available bedside variables with machine learning and logistic regression concordance
Limitations
- Observational design limits causal inference regarding lipid manipulation and outcomes
- Generalizability beyond studied settings/populations requires further validation and assessment of assay standardization
Future Directions: Prospective interventional trials testing lipid-modulating or host-response therapies in the HYPO subphenotype; validation across diverse health systems and integration into sepsis clinical pathways.
Background: Cholesterol metabolism is dysregulated in sepsis contributing to patient heterogeneity. Subphenotypes displaying lower lipoprotein levels and higher mortality (previously subphenotyped hypolipoprotein phenotype [HYPO]) or higher lipoprotein levels and lower mortality (previously subphenotyped normolipoprotein phenotype [NORMO]) were described. We developed a simplified clinical algorithm for bedside subphenotype recognition. Methods: We analyzed data from four prospective studies (internal dataset), focusing on HYPO and NORMO subphenotypes. A 1,000-tree random forest classifier and logistic regression models were built, using clinical features to predict subphenotypes. Performance was evaluated by comparing predictions to actual subphenotypes derived from a machine learning model. The model was applied to an external dataset of 281 patients from three French studies. Results: The internal cohort consisted of 386 patients (median age, 63 years; 46% female). Four clinical features (hepatic SOFA, cardiovascular SOFA, low [low-density lipoprotein cholesterol {LDL-C}] and high-density lipoprotein cholesterol [high-density lipoprotein cholesterol {HDL-C}]) predicted HYPO versus NORMO subphenotypes with an area under the receiver operating characteristic curve of 0.86, a sensitivity of 0.771, and a specificity of 0.779. In the internal dataset, 28-day mortality for HYPO versus NORMO patients was 26% versus 15%, and in the external cohort, 30% versus 10%. HYPO internal versus external dataset LDL-C levels were similar ( P = 0.99), but HDL-C ( P = 0.02) levels were different. Median NORMO internal versus external dataset LDL-C ( P = 0.99) and HDL-C ( P = 0.12) levels were similar. HYPO patients had lower LDL-C, HDL-C and total cholesterol than NORMO patients in both internal and external datasets. Conclusions: Our simplified clinical data algorithm may allow for bedside recognition of septic patients displaying lipid dysregulation subphenotypes. External validation is needed to verify these results.
2. PREDICTIVE VALUE OF H3K18 LACTYLATION FOR EARLY DETECTION AND PROGNOSIS OF SEPSIS-RELATED ACUTE RESPIRATORY DISTRESS SYNDROME: A PROSPECTIVE OBSERVATIONAL CLINICAL STUDY.
In a prospective ICU cohort (n=91), BALF H3K18 lactylation was elevated in sepsis-related ARDS, correlated with inflammation and severity, independently predicted ARDS, and achieved AUC 0.804 (0.830 with SOFA; sensitivity 88.9%, specificity 67.3%). Day-3 levels rose further among non-survivors.
Impact: Introduces a mechanistically plausible, epigenetic airway biomarker for early detection and risk stratification in sepsis-related ARDS with actionable diagnostic performance.
Clinical Implications: BALF H3K18 lactylation could augment early identification and prognosis of ARDS (acute respiratory distress syndrome) in sepsis, supporting earlier lung-protective strategies, escalation decisions, and enrollment into phenotype-targeted trials.
Key Findings
- BALF H3K18la was significantly higher in sepsis-related ARDS vs non-ARDS and correlated with lactate, IL-6, TNF-α, APACHE II, and SOFA.
- H3K18la independently predicted ARDS with AUC 0.804; combined with SOFA improved AUC to 0.830 (sensitivity 88.9%, specificity 67.3%).
- Day-3 H3K18la levels further increased among non-survivors, indicating prognostic value.
Methodological Strengths
- Prospective design with early (day-1) and dynamic (day-3) BALF sampling
- Multivariable modeling and ROC analysis demonstrating independent predictive value and incremental utility with SOFA
Limitations
- Single-center, modest sample size limits generalizability
- BALF sampling may not be feasible for all sepsis patients; external validation absent
Future Directions: Validate BALF H3K18la cutoffs across centers, assess minimally invasive surrogates (e.g., plasma), and test response to lactate/epigenetic-modulating therapies in phenotype-enriched trials.
Background: This study aimed to investigate the predictive value of histone H3 lysine 18 lactylation (H3K18la) for the early identification and prognosis of sepsis-related acute respiratory distress syndrome (ARDS). Methods: This prospective observational study included patients with sepsis admitted to the intensive care unit (ICU) between March 2023 and September 2024. The patients were divided into two groups: the sepsis with ARDS group and the sepsis without ARDS group. Clinical data were collected within 24 h of ICU admission. Bronchoalveolar lavage fluid (BALF) samples were obtained on day 1 for all participants, and a second BALF sample was collected on day 3 from patients requiring continued mechanical ventilation. Results: In total, 91 sepsis patients were enrolled in the study: 36 with ARDS and 55 without ARDS. H3K18la levels in BALF were significantly higher in the sepsis-related ARDS group than in the non-ARDS group and the control group ( P < 0.05). Elevated H3K18la levels were positively correlated with inflammatory markers (lactate, IL-6, and TNF-α), Acute Physiology and Chronic Health Evaluation II scores, and Sequential Organ Failure Assessment scores ( P < 0.01). Logistic regression analysis revealed that H3K18la was an independent predictor of ARDS development ( P < 0.05), and ROC curve analysis revealed that H3K18la had high diagnostic accuracy (AUC = 0.804). Combining H3K18la with the Sequential Organ Failure Assessment score further improved diagnostic performance (AUC = 0.830, sensitivity = 88.9%, specificity = 67.3%). Furthermore, H3K18la levels significantly increased on day 3 in the mortality group. Conclusion: H3K18la is a promising biomarker for the early identification and prognostic prediction of sepsis-related ARDS.
3. INFLAMMATORY PROTEIN SIGNATURES OF SEPSIS RISK AND MORTALITY: A MENDELIAN RANDOMIZATION STUDY.
Two-sample Mendelian randomization using protein GWAS (n=14,824) and UK Biobank (>500,000) supports causal links between inflammatory proteins and sepsis. β-NGF appears protective against sepsis (OR 0.77; 0.70 in <75 years), whereas TRAIL and VEGF-A increase risk; CST5 and MCP-1 associate with lower sepsis-related mortality.
Impact: Provides causal evidence implicating specific inflammatory proteins in sepsis pathogenesis, guiding target selection for preventive and therapeutic development.
Clinical Implications: β-NGF, VEGF-A, TRAIL, CST5, and MCP-1 emerge as candidate biomarkers and therapeutic targets for risk stratification and intervention trials in sepsis.
Key Findings
- Genetically higher β-NGF was associated with lower sepsis risk (OR 0.77; P=0.039), stronger in <75 years (OR 0.70; P=0.013).
- Genetically higher TRAIL (OR 1.11; P=0.020) and VEGF-A (OR 1.18; P=0.031) were associated with increased sepsis incidence.
- CST5 (OR 0.81; P=0.006) and MCP-1 (OR 0.64; P=0.015) were inversely associated with sepsis-induced mortality.
Methodological Strengths
- Two-sample MR with large cohorts and multiple sensitivity analyses (IVW, MR-Egger, weighted median)
- Age-stratified analyses and evaluation of mortality and ICU admission outcomes
Limitations
- Findings derived predominantly from European ancestry cohorts; generalizability to other ancestries needs validation
- Residual horizontal pleiotropy and limitations of protein genetic instruments cannot be fully excluded
Future Directions: Functional validation of protein targets, development of pharmacologic modulators, and randomized trials in genetically and clinically enriched populations.
Objective: Sepsis represents a leading cause of global mortality, defined by a dysregulated inflammatory response. This study aims to investigate the potential causal associations between circulating inflammatory proteins and sepsis risk using a two-sample Mendelian randomization (MR) approach. Methods: Publicly available summary statistics from genomewide association studies (GWAS) were used in this study. Genetic instruments for circulating inflammatory protein were derived from a GWAS meta-analysis of 11 cohorts encompassing 14,824 European participants. The relationship between genetically predicted protein levels and sepsis-related outcomes was evaluated using aggregated data from the UK Biobank-a multicenter prospective cohort study comprising over 500,000 European participants. Analyses were stratified by age, 28-day mortality, and ICU admission. Multiple MR methods, including inverse-variance weighted (IVW), MR-Egger, and weighted median, were applied to ensure the robustness of our findings. Results: The MR analysis identified significant causal associations between inflammatory proteins and sepsis outcomes. Genetically predicted elevated levels of β-NGF are associated with a reduced risk of sepsis (odds ratio [OR] 0.77, 95% confidence interval [CI] = 0.60-0.99; P = 0.039). Among sepsis patients aged below 75 years, the risk was reduced by 30% (OR, 0.70; 95% CI = 0.52-0.93; P = 0.013). Genetically predicted increases in TRAIL (OR, 1.11; 95% CI = 1.02-1.20; P = 0.020) and VEGF-A (OR, 1.18; 95% CI = 1.02-1.37; P = 0.031) were positively associated with sepsis incidence, while genetically predicted levels of CST5 (OR, 0.81; 95% CI = 0.69-0.94; P = 0.006) and MCP-1 (OR, 0.64; 95% CI = 0.45-0.92; P = 0.015) were inversely associated with sepsis-induced mortality. Conclusion: This study provides evidence from a Mendelian randomization framework supporting the causal role for specific circulating inflammatory proteins (e.g., β-NGF, VEGF-A, and TRAIL) in influencing sepsis risk and mortality. These findings underscore the potential for therapeutic interventions targeting these proteins to mitigate sepsis risk and improve patient outcomes, along with further investigation into the underlying mechanisms and clinical implications.