The bidirectional interactions between the gut microbiota and sepsis-associated encephalopathy (SAE) are not well characterized. We found that the gut microbiota was more severely disturbed in SAE-susceptible (SES) mice than in SAE-resistant (SER) mice after sepsis modeling.

Purpose Neuroinflammation plays an important part in the pathophysiology of sepsis-associated encephalopathy (SAE). Gut microbiota and gut brain axis are considered as important mediators in the development of neurological diseases. The aim of this study was to investigate the role of intestinal microbiota in sepsis-related brain injury and to explore the underlying mechanisms. Methods Mouse model of SAE was established using cecal ligation and puncture (CLP). Based on the mouse mortality and the associated time of death, light SAE (LSAE) and severe SAE (SSAE) were classified. Fecal microbiota transplantation (FMT) was performed to verify the role of intestinal microbiota. Feces of mice in the two groups which collected before operation were sequenced for 16S and targeted short chain fatty acids. Results Intestinal microbiota from SSAE and LSAE mice displayed diverse functions. Interestingly, LSAE mice produced more butyric acid compared with SSAE mice. In the in vivo experiments, sodium butyrate (NaB) reduced the high oxidative stress levels in mice hippocampus and conferred a marked survival superiority to sepsis mice. In addition, NaB prevented the increase in intracellular reactive oxygen species (ROS) generation and inducible nitric-oxide synthase expression in LPS-stimulated primary microglia. The GPR109A/Nrf2/HO-1 signaling pathway was found to be involved in the activation of antioxidant response of primary microglia induced by sodium butyrate. Conclusion Our findings indicate a crucial role of gut microbiota in the susceptibility to SAE. Butyrate, a metabolite of intestinal microbiota, may have a neuroprotective effect in the process of sepsis by GPR109A/Nrf2/HO-1 pathway.

Background It is not clear whether there are valuable inflammatory markers for prognosis judgment in the intensive care unit (ICU). We therefore conducted a multicenter, prospective, observational study to evaluate the prognostic role of inflammatory markers. Methods The clinical and laboratory data of patients at admission, including C-reactive protein (CRP), were collected in four general ICUs from September 1, 2018, to August 1, 2019. Multivariate logistic regression was used to identify factors independently associated with nonsurvival. The area under the receiver operating characteristic curve (AUC-ROC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to evaluate the effect size of different factors in predicting mortality during ICU stay. 3 -knots were used to assess whether alternative cut points for these biomarkers were more appropriate. Results A total of 813 patients were recruited, among whom 121 patients (14.88%) died during the ICU stay. The AUC-ROC values of PCT and CRP for discriminating ICU mortality were 0.696 (95% confidence interval [CI], 0.650–0.743) and 0.684 (95% CI, 0.633–0.735), respectively. In the multivariable analysis, only APACHE II score (odds ratio, 1.166; 95% CI, 1.129–1.203; P = 0.000) and CRP concentration > 62.8 mg/L (odds ratio, 2.145; 95% CI, 1.343–3.427; P = 0.001), were significantly associated with an increased risk of ICU mortality. Moreover, the combination of APACHE II score and CRP > 62.8 mg/L significantly improved risk reclassification over the APACHE II score alone, with NRI (0.556) and IDI (0.013). Restricted cubic spline analysis confirmed that CRP concentration > 62.8 mg/L was the optimal cut-off value for differentiating between surviving and nonsurviving patients. Conclusion CRP markedly improved risk reclassification for prognosis prediction.