Patients with sepsis experience metabolic and immunologic dysfunction that may be amplified by standard carbohydrate-based nutrition. A ketogenic diet (KD) may offer an immunologically advantageous alternative, although clinical evidence is limited. We conducted a single-center, open-label, randomized controlled trial to assess whether a KD could induce stable ketosis in critically ill patients with sepsis. Secondary outcomes included assessment of feasibility and safety of KD, as well as explorative analysis of clinical and immunological characteristics. Forty critically ill adults were randomized to either a ketogenic or standard high-carbohydrate diet. Stable ketosis was achieved in all KD patients, with significant increases in β-hydroxybutyrate levels compared with controls [mean difference 1.4 milimoles per liter; 95% confidence interval (CI): 1.0 to 1.8; P < 0.001). No major adverse events or harmful metabolic side effects (acidosis, dysglycemia, or dyslipidemia) were observed. After day 4, none of the patients in the KD group required insulin treatment, whereas in the control group, insulin dependency ranged between 35% and 60% ( P = 0.009). There were no differences in 30-day survival, but ventilation-free [incidence rate ratio (IRR) 1.7; 95% CI: 1.5 to 2.1; P < 0.001], vasopressor-free (IRR 1.7; 95% CI: 1.5 to 2.0; P < 0.001), dialysis-free (IRR 1.5; 95% CI: 1.3 to 1.8; P < 0.001), and intensive care unit–free days (IRR 1.7; 95% CI: 1.4 to 2.1; P < 0.001) were higher in the ketogenic group. Next-generation sequencing of CD4 ⁺ /CD8 ⁺ T cells and protein analyses showed reduced immune dysregulation, with decreased gene expression of T-cell activation and signaling markers and lower pro-inflammatory cytokine secretion. This trial demonstrated the safe induction of a stable ketogenic state in sepsis, warranting larger trials to investigate potential benefits in sepsis-related organ dysfunction.

Sepsis, a severe global healthcare challenge, is characterized by significant morbidity and mortality. The 2016 redefinition by the Third International Consensus Definitions Task Force emphasizes its complexity as a “life-threatening organ dysfunction caused by a dysregulated host response to infection”. Bacterial pathogens, historically dominant, exhibit geographic variations, influencing healthcare strategies. The intricate dynamics of bacterial immunity involve recognizing pathogen-associated molecular patterns, triggering innate immune responses and inflammatory cascades. Dysregulation leads to immunothrombosis, disseminated intravascular coagulation, and mitochondrial dysfunction, contributing to the septic state. Viral sepsis, historically less prevalent, saw a paradigm shift during the COVID-19 pandemic, underscoring the need to understand the immunological response. Retinoic acid-inducible gene I-like receptors and Toll-like receptors play pivotal roles, and the cytokine storm in COVID-19 differs from bacterial sepsis. Latent viruses like human cytomegalovirus impact sepsis by reactivating during the immunosuppressive phases. Challenges in sepsis management include rapid pathogen identification, antibiotic resistance monitoring, and balancing therapy beyond antibiotics. This review highlights the evolving sepsis landscape, emphasizing the need for pathogen-specific therapeutic developments in a dynamic and heterogeneous clinical setting.

Background: The COVID-19 pandemic has taken a toll on health care systems worldwide, which has led to increased mortality of different diseases like myocardial infarction. This is most likely due to three factors. First, an increased workload per nurse ratio, a factor associated with mortality. Second, patients presenting with COVID-19-like symptoms are isolated, which also decreases survival in cases of emergency. And third, patients hesitate to see a doctor or present themselves at a hospital. To assess if this is also true for sepsis patients, we asked whether non-COVID-19 sepsis patients had an increased 30-day mortality during the COVID-19 pandemic. Methods: This is a post hoc analysis of the SepsisDataNet.NRW study, a multicentric, prospective study that includes septic patients fulfilling the SEPSIS-3 criteria. Within this study, we compared the 30-day mortality and disease severity of patients recruited pre-pandemic (recruited from March 2018 until February 2020) with non-COVID-19 septic patients recruited during the pandemic (recruited from March 2020 till December 2020). Results: Comparing septic patients recruited before the pandemic to those recruited during the pandemic, we found an increased raw 30-day mortality in sepsis-patients recruited during the pandemic (33% vs. 52%, p = 0.004). We also found a significant difference in the severity of disease at recruitment (SOFA score pre-pandemic: 8 (5 - 11) vs. pandemic: 10 (8 - 13); p < 0.001). When adjusted for this, the 30-day mortality rates were not significantly different between the two groups (52% vs. 52% pre-pandemic and pandemic, p = 0.798). Conclusions: This led us to believe that the higher mortality of non-COVID19 sepsis patients during the pandemic might be attributed to a more severe septic disease at the time of recruitment. We note that patients may experience a delayed admission, as indicated by elevated SOFA scores. This could explain the higher mortality during the pandemic and we found no evidence for a diminished quality of care for critically ill sepsis patients in German intensive care units.

Background: Sepsis is one of the leading causes of death. Treatment attempts targeting the immune response regularly fail in clinical trials. As HCMV latency can modulate the immune response and changes the immune cell composition, we hypothesized that HCMV serostatus affects mortality in sepsis patients. Methods: We determined the HCMV serostatus (i.e., latency) of 410 prospectively enrolled patients of the multicenter SepsisDataNet.NRW study. Patients were recruited according to the SEPSIS-3 criteria and clinical data were recorded in an observational approach. We quantified 13 cytokines at Days 1, 4, and 8 after enrollment. Proteomics data were analyzed from the plasma samples of 171 patients. Results: The 30-day mortality was higher in HCMV-seropositive patients than in seronegative sepsis patients (38% vs. 25%, respectively; p = 0.008; HR, 1.656; 95% CI 1.135–2.417). This effect was observed independent of age (p = 0.010; HR, 1.673; 95% CI 1.131–2.477). The predictive value on the outcome of the increased concentrations of IL-6 was present only in the seropositive cohort (30-day mortality, 63% vs. 24%; HR 3.250; 95% CI 2.075–5.090; p < 0.001) with no significant differences in serum concentrations of IL-6 between the two groups. Procalcitonin and IL-10 exhibited the same behavior and were predictive of the outcome only in HCMV-seropositive patients. Conclusion: We suggest that the predictive value of inflammation-associated biomarkers should be re-evaluated with regard to the HCMV serostatus. Targeting HCMV latency might open a new approach to selecting suitable patients for individualized treatment in sepsis.

Mitochondrial DNA (mtDNA) plays a vital role as a damage-associated molecular pattern in sepsis being able to shape the immune response. Since pathogen recognition receptors of innate immune cells are activated by demethylated DNA only, we set out to investigate the amount of DNA methyltransferase 1 (DNMT1) in mitochondria and the extent of mtDNA methylation in a human endotoxin model. Peripheral blood mononuclear cells of 20 healthy individuals were isolated from whole blood and stimulated with lipopolysaccharide (LPS) for 48 h. Subsequently, DNMT1 protein abundance was assessed in whole cells and a mitochondrial fraction. At the same time, methylation levels of mtDNA were quantified, and cytokine expression in the supernatant was measured. Despite increased cellular expression of DNMT1 after LPS stimulation, the degree of mtDNA methylation slightly decreased. Strikingly the mitochondrial protein abundance of DNMT1 was reduced by 50% in line with the lower degree of mtDNA methylation. Although only modest alterations were seen in the degree of mtDNA methylation, these strongly correlated with IL-6 and IL-10 expression. Our data may hint at a protein import problem for DNMT1 into the mitochondria under LPS stimulation and suggest a role of demethylated mtDNA in the regulation of the inflammatory immune response.

The quantity of aquaporin 5 protein in neutrophil granulocytes is associated with human sepsis-survival. The C-allele of the aquaporin (AQP5)-1364A/C polymorphism was shown to be associated with decreased AQP5 expression, which was shown to be relevant in this context leading towards improved outcomes in sepsis. To date, the underlying mechanism of the C-allele—leading to lower AQP5 expression—has been unknown. Knowing the detailed mechanism depicts a crucial step with a target to further interventions. Genotype-dependent regulation of AQP5 expression might be mediated by the epigenetic mechanism of promoter methylation and treatment with epigenetic-drugs could maybe provide benefit. Hence, we tested the hypothesis that AQP5 promoter methylation differs between genotypes in specific types of immune cells.: AQP5 promoter methylation was quantified in cells of septic patients and controls by methylation-specific polymerase chain reaction and quantified by a standard curve. In cell-line models, AQP5 expression was analyzed after demethylation to determine the impact of promoter methylation on AQP5 expression. C-allele of AQP5-1364 A/C promoter polymorphism is associated with a five-fold increased promoter methylation in neutrophils (p = 0.0055) and a four-fold increase in monocytes (p = 0.0005) and lymphocytes (p = 0.0184) in septic patients and healthy controls as well. In addition, a decreased AQP5 promoter methylation was accompanied by an increased AQP5 expression in HL-60 (p = 0.0102) and REH cells (p = 0.0102). The C-allele which is associated with lower gene expression in sepsis is accompanied by a higher methylation level of the AQP5 promoter. Hence, AQP5 promoter methylation could depict a key mechanism in genotype-dependent expression.