Daily Sepsis Research Analysis
Three papers advance sepsis care across dosing, mechanisms, and therapeutics: a multinational PK study delivers practical nomograms for meropenem and piperacillin/tazobactam during renal replacement therapy; a cfDNA multi-omic analysis reframes elevated cfDNA in sepsis as primarily impaired hepatic clearance and reveals diagnostic potential; and a humanized anti-CitH3 antibody reduces inflammation, lung injury, and mortality in preclinical models with a biomarker-defined therapeutic window.
Summary
Three papers advance sepsis care across dosing, mechanisms, and therapeutics: a multinational PK study delivers practical nomograms for meropenem and piperacillin/tazobactam during renal replacement therapy; a cfDNA multi-omic analysis reframes elevated cfDNA in sepsis as primarily impaired hepatic clearance and reveals diagnostic potential; and a humanized anti-CitH3 antibody reduces inflammation, lung injury, and mortality in preclinical models with a biomarker-defined therapeutic window.
Research Themes
- Optimized antibiotic dosing during renal replacement therapy
- cfDNA biology and diagnostic potential in sepsis
- Immunomodulatory therapy targeting CitH3/NETosis
Selected Articles
1. Meropenem and piperacillin/tazobactam optimised dosing regimens for critically ill patients receiving renal replacement therapy.
In a 12-country prospective PK study (n=300) across multiple RRT modalities, dosing requirements for meropenem and piperacillin/tazobactam depended on urine output and RRT intensity/duration. Extended or continuous infusions achieved PK/PD targets more reliably with lower daily doses, and validated nomograms were provided for Enterobacterales and Pseudomonas aeruginosa targets.
Impact: This study fills a critical dosing gap for two cornerstone antipseudomonal beta-lactams in RRT, delivering externally validated nomograms and practical guidance on infusion strategies.
Clinical Implications: Adopt extended/continuous infusions and apply the provided nomograms incorporating urine output and RRT settings to improve target attainment; consider therapeutic drug monitoring to individualize dosing.
Key Findings
- Prospective, multinational PK models (n=300; 12 countries) with external validation (66 patients) showed high predictive performance (mean prediction error −5.2% meropenem; −16.9% piperacillin).
- Dosing requirements varied with urine output and RRT intensity/duration (p<0.05).
- Extended/continuous infusions achieved effective unbound concentrations over 100% of dosing interval more consistently and with lower daily doses than short infusions.
- Nomograms were developed for different RRT settings, urine outputs, and PK/PD targets against Enterobacterales and Pseudomonas aeruginosa.
Methodological Strengths
- Prospective, multicenter design with large sample size and external validation across 12 countries and multiple RRT modalities
- Robust population PK modeling with Monte Carlo simulations and quantification of unbound target attainment
Limitations
- Clinical outcomes (e.g., mortality, clinical cure) were not directly tested against dosing strategies
- Generalizability may vary with center-specific practices, protein binding assumptions, and device heterogeneity
Future Directions: Prospective trials to test nomogram-guided dosing against clinical outcomes; integration with bedside therapeutic drug monitoring and adaptive dosing algorithms.
PURPOSE: Optimal dosing of meropenem and piperacillin/tazobactam in critically ill patients receiving renal replacement therapy (RRT) is uncertain due to variable pharmacokinetics. We aimed to develop generalisable optimised dosing recommendations for these antibiotics. METHODS: Prospective, multinational pharmacokinetic study including patients requiring various forms of RRT. Independent population PK models were developed, externally validated and applied to perform Monte Carlo dosing simulations using Monolix and Simulx. We calculated the probability that these dosing regimens achieved standard and high therapeutic unbound antibiotic concentrations over 100% of the dosing interval for the treatment of Enterobacterales and Pseudomonas aeruginosa. RESULTS: We enrolled 300 patients from 22 intensive care units across 12 countries receiving continuous veno-venous haemodialysis (13.0%), haemofiltration (23.3%), haemodiafiltration (48.4%) or sustained low-efficiency dialysis (15.3%). Models were developed using data from 234 patients (8322 samples) and validated with 66 additional patients (560 samples). Predictive performance was high, with mean prediction errors of - 5.2% for meropenem and - 16.9% for piperacillin. Dosing simulations showed that meropenem and piperacillin/tazobactam dosing requirements were dependent on urine output and RRT intensity and duration (p < 0.05). In all scenarios, extended/continuous infusions led to a better achievement of effective concentrations with lower daily doses compared to short infusion. Dosing nomograms were developed to inform dosing for different RRT settings, urine outputs, and target concentrations. CONCLUSION: RRT intensity and duration and urine output determine meropenem and piperacillin/tazobactam dosing requirements in critically ill patients receiving RRT. Extended/continuous infusions facilitate the attainment of effective concentrations.
2. A citrullinated histone H3 monoclonal antibody for immune modulation in sepsis.
A humanized anti-CitH3 monoclonal antibody suppressed cytokines, mortality, and acute lung injury in LPS and Pseudomonas aeruginosa murine sepsis models, while enhancing bacterial phagocytosis. Pre-equilibrium digital ELISA defined a therapeutic window, and mechanistic work implicated TLR2 activation in macrophages by CitH3.
Impact: Introduces a first-in-class immunomodulatory strategy targeting CitH3 and pairs it with a biomarker assay to time therapy, bridging mechanism and translational potential.
Clinical Implications: If validated in humans, anti-CitH3 therapy could attenuate hyperinflammation and organ injury in sepsis; the digital ELISA may guide patient selection and timing.
Key Findings
- Humanized anti-CitH3 mAb demonstrated high affinity/specificity and reduced cytokine production, mortality, and acute lung injury in LPS and Pseudomonas aeruginosa murine models.
- Enhanced bacterial phagocytosis in lungs, spleen, and liver accompanied therapeutic benefit.
- Pre-equilibrium digital ELISA (PEdELISA) identified an optimal therapeutic window in sepsis-induced acute lung injury.
- Mechanistically, CitH3 activated TLR2 in macrophages, linking histone modification products to innate immune signaling and inflammatory amplification.
Methodological Strengths
- Multiple in vivo sepsis/ALI models (LPS, P. aeruginosa) with consistent phenotypic and survival readouts
- Integration of digital ELISA for biomarker-guided timing and receptor-level mechanistic studies
Limitations
- Evidence is preclinical; human safety, dosing, and efficacy remain untested
- Potential off-target effects and immunogenicity risks require rigorous evaluation
Future Directions: First-in-human phase I studies with PEdELISA-guided dosing; exploration of combination with standard antibiotics and assessment across sepsis endotypes.
Citrullinated histone H3 (CitH3), released from immune cells during early sepsis, drives a vicious cycle of inflammation through excessive NETosis and pyroptosis, causing immune dysfunction and tissue damage. To regulate this process, we develop a humanized CitH3 monoclonal antibody (hCitH3-mAb) with high affinity and specificity to target this process. In murine models, hCitH3-mAb reduces cytokine production, mortality and acute lung injury (ALI) caused by LPS and Pseudomonas aeruginosa while enhancing bacteria phagocytosis in the lungs, spleen, and liver. Using pre-equilibrium digital ELISA (PEdELISA), we identify an optimal therapeutic window for hCitH3-mAb in sepsis-induced ALI. In parallel, we explore the molecular mechanism underlying CitH3-driven inflammation. We find that in macrophages, CitH3 activates Toll-like receptor 2 (TLR2), triggering Ca
3. The circulating cell-free DNA landscape in sepsis is dominated by impaired liver clearance.
cfDNA increased 41-fold in sepsis, but its composition resembled controls, supporting impaired hepatic clearance rather than excess cell death as the driver. Nucleosome footprints and integration with single-cell data highlighted liver-origin signals in dysfunction, and pathogen-derived cfDNA underscores diagnostic value.
Impact: This study reframes cfDNA biology in sepsis by implicating hepatic clearance failure and delivers analytical approaches (nucleosome footprints) that expand cfDNA’s diagnostic potential.
Clinical Implications: cfDNA profiling may inform liver dysfunction and pathogen detection in sepsis and could guide risk stratification; interventions supporting hepatic clearance warrant exploration.
Key Findings
- cfDNA increased 41-fold in sepsis, yet methylation-based deconvolution showed similar tissue composition to controls, implicating impaired hepatic clearance.
- Fragmentation and end-motif signatures suggested prolonged nuclease exposure, supporting the clearance hypothesis.
- Novel quantification of nucleosome footprints integrated with single-cell data revealed increased cfDNA from Kupffer cells and hepatocytes in liver dysfunction.
- cfDNA contained pathogen-derived material, indicating diagnostic potential for infection characterization.
Methodological Strengths
- High-throughput, multimodal cfDNA analysis combining methylation deconvolution, fragmentation/end-motif profiling, and nucleosome footprinting
- Integration of nucleosome footprints with single-cell data to infer tissue-of-origin changes in liver dysfunction
Limitations
- Observational design limits causal inference; clinical decision impact not tested
- Sample size and cohort characteristics are not specified in the abstract, limiting generalizability assessment
Future Directions: Prospective validation of cfDNA-based risk stratification and pathogen detection; interventional studies targeting hepatic clearance pathways in sepsis.
Circulating cell-free DNA (cfDNA) is a promising molecular biomarker, but its role in severe infection is unclear. Here, we profile cfDNA from sepsis patients and controls, demonstrating a 41-fold increase during disease. Methylation-based deconvolution revealed similar cfDNA compositions in the two groups, suggesting that cfDNA accumulation during disease is due not to excess cell death but to impaired hepatic clearance. Fragmentation and end-motif patterns both support this hypothesis, suggesting prolonged exposure of cfDNA to circulating nucleases. In addition, we show that cfDNA retains nucleosome footprints informative of gene activity. By developing a novel method to quantify these footprints and integrate them with single-cell data, we report an increase in cfDNA from Kupffer cells and liver parenchyma in patients with liver dysfunction. Finally, we show that cfDNA contains pathogen-derived material, highlighting its diagnostic potential. This high-throughput, multimodal study provides a reference for understanding cfDNA's role in sepsis and critical illness.