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Increasing evidence demonstrates that pyroptosis, pro-inflammatory programmed cell death, is linked to acute lung injury (ALI). Dihydromyricetin (DHM) has been reported to exert anti-inflammatory effects by inhibiting NLRP3 inflammasome activation in vascular endothelial cells. However, the effects of DHM on NLRP3 inflammasome-induced pyroptosis in ALI remain elusive. In the present study, male BALB/c mice were subjected to cecal ligation and puncture (CLP), and DHM (50, 100, 150 mg/kg) was orally administered (once per day, for 3 days) 2 h after CLP. After 72 h, lung histopathology was examined, and the wet/dry (W/D) ratio, inflammatory infiltration, total protein concentration, total cell, and neutrophil counts were detected. Myeloperoxidase (MPO), interleukin (IL)-6, TNF-α, IL-1β, and IL-18 levels in bronchoalveolar lavage fluid (BALF) were measured by ELISA. Additionally, the expression of NLRP3 signaling pathway proteins were detected by Western blotting. The results revealed that in BALF, DHM (150 mg/kg) treatment significantly reduced the CLP-induced lung histopathological injury, inflammatory cell infiltration, total cell and neutrophil number, and total protein and albumin concentration. DHM treatment significantly inhibited the CLP-induced NLRP3 inflammasome pathway (NLRP3, ASC, caspase-1, gasdermin D (Gsdmd), IL-1β, and IL-18). In conclusion, these results demonstrate that DHM protects against CLP-induced ALI by inhibiting NLRP3 inflammasome activation and subsequent pyroptosis.

Objectives Septic shock is a subset of sepsis related to acute circulatory failure characterized by severe immunosuppression and high mortality. Current knowledge about B-cell status in the immunosuppressive phase of septic shock is sparse. The aim of this study was to investigate the alterations of B Cells in the immunosuppressive phase of septic shock. Design Prospective cohort study. Setting Adult ICUs at a university hospital. Patients Adult septic shock patients without any documented immune comorbidity. Interventions None. Measurements and main results The absolute counts of lymphocytes and B cells of 81 patients and 13 healthy controls, and serum immunoglobulin levels of 64 patients and 10 healthy controls were determined by clinical laboratory. The percentages and counts of B-cell subsets of 33 patients and 10 healthy controls and the immunoglobulin M expression on B-cell subsets of 20 patients and five healthy controls were quantified by flow cytometry. Immunoglobulin levels produced by B cells after stimulation in vitro of 20 patients and five healthy controls were tested by enzyme-linked immunosorbent assay. Redistribution and selective depletion of B-cell subsets in septic shock patients were discovered, and a decrease in immunoglobulin M levels was associated with a reduction in resting memory B-cell counts. These alterations were more pronounced in nonsurvivors compared with survivors. Additionally, receiver operating characteristic curve analysis showed that the data of B-cell subsets had the best predictive value for mortality risk. Conclusions Severe B-cell abnormalities are present in the immunosuppressive phase of septic shock and are associated with prognosis.

Aims Increasing evidence indicates that FK866, a specific noncompetitive nicotinamide phosphoribosyl transferase inhibitor, exhibits a protective effect on acute lung injury (ALI). Autophagy plays a pivotal role in sepsis-induced ALI. However, the contribution of autophagy and the underlying mechanism by which FK866-confered lung protection remains elusive. Herein, we aimed to study whether FK866 could alleviate sepsis-induced ALI via the JNK-dependent autophagy. Main methods Male C57BL/6 mice were subjected to cecal ligation and puncture (CLP) to establish the polymicrobial sepsis mice model, and treated with FK866 (10 mg/kg) at 24, 12 and 0.5 h before the CLP procedure. The lung protective effects were measured by lung histopathology, tissue edema, vascular leakage, inflammation infiltration, autophagy-related protein expression and JNK activity. A549 cells were stimulated with LPS (1000 ng/ml) to generate the ALI cell model, and pretreated with FK866 or SP600125 for 30 min to measure the autophagy-related protein expression and JNK activity. Key findings Our results demonstrated that FK866 reduced lung injury score, tissue edema, vascular leakage, and inflammatory infiltration, and upregulated autophagy. The protective effect of autophagy conferred by FK866 on ALI was further clarified by using 3-methyladenine (3MA) and rapamycin. Additionally, the activity of JNK was suppressed by FK866, and inhibition of JNK promoted autophagy and showed a benefit effect. Significance Our study indicates that FK866 protects against sepsis-induced ALI by induction of JNK-dependent autophagy. This may provide new insights into the functional mechanism of NAMPT inhibition in sepsis-induced ALI.

Purpose. Pyroptosis has been known to play a vital role in the inflammation process which was induced by infection, injury, or inflammatory disease. The present study was aimed at evaluating the percentage of peripheral blood mononuclear cell (PBMC) pyroptosis in septic patients and assessing the correlation of PBMC pyroptosis with the severity and the mortality of septic patients. Methods. 128 trauma-induced patients with sepsis were enrolled in this prospective cohort study. Blood samples were collected, and PBMC pyroptosis was measured by flow cytometry within 24 hours after sepsis was diagnosed. Results. Percentage of PBMC pyroptosis was positively correlated with the acute physiology and chronic health evaluation (APACHE) II score and sequential organ failure assessment (SOFA) score (all P<0.01). The area under the curve (AUC) for the percentage of PBMC pyroptosis on a receiver operating characteristic curve was 0.79 (95% confidence interval (CI), 0.68–0.90). A Cox proportional hazard model identified an association between an increased percentage of PBMC pyroptosis (>14.17%) and increased risk of the 28-day mortality (hazard ratio=1.234, 95% CI, 1.014–1.502). Conclusion. The percentage of PBMC pyroptosis increases in septic patients, and the increased percentage of PBMC pyroptosis is associated with the severity of sepsis and the 28-day mortality of patients with sepsis.

Sepsis-associated encephalopathy (SAE) manifested clinically in acute and long-term cognitive impairments and associated with increased morbidity and mortality worldwide. The potential pathological changes of SAE are complex and remain to be elucidated. Pyroptosis, a novel programmed cell death, is executed by caspase-1-cleaved GSDMD N-terminal (GSDMD-NT) and we investigated it in peripheral blood immunocytes of septic patients previously. Here, a caspase-1 inhibitor VX765 was treated with CLP-induced septic mice. Novel object recognition test indicated that VX765 treatment reversed cognitive dysfunction in septic mice. Elevated plus maze, tail suspension test and open field test revealed that depressive-like behaviors of septic mice were relieved. Inhibited caspase-1 suppressed the expressions of GSDMD and its cleavage form GSDMD-NT, and reduced pyroptosis in brain at day 1 and day 7 after sepsis. Meantime, inhibited caspase-1 mitigated the expressions of IL-1β, MCP-1 and TNF-α in serum and brain, diminished microglia activation in septic mice, and reduced sepsis-induced brain-blood barrier disruption and ultrastructure damages in brain as well. Inhibited caspase-1 protected the synapse plasticity and preserved long-term potential, which may be the possible mechanism of cognitive functions protective effects of septic mice. In conclusion, caspase-1 inhibition exerts brain-protective effects against SAE and cognitive impairments in a mouse model of sepsis.

Monocyte chemoattractant protein 1 (MCP-1) is an initiating cytokine of the inflammatory cascade. Extracellular MCP-1 exhibits pro-inflammatory characteristic and plays a central pathogenic role in critical illness. The purpose of the study was to identify the association between plasma MCP-1 levels and the development of sepsis after severe trauma.The plasma levels of MCP-1 in severe trauma patients were measured by a quantitative enzyme-linked immune sorbent assay and the dynamic release patterns were recorded at three time points during seven days post-trauma. The related factors of prognosis were compared between sepsis and non-sepsis groups and analyzed using multivariate logistic regression analysis. We also used receiver operating characteristic (ROC) curves to assess the values of different variables in predicting sepsis.A total of 72 patients who met criteria indicative of severe trauma (72.22% of male; mean age, 49.40 ± 14.29 years) were enrolled. Plasma MCP-1 concentrations significantly increased on post-trauma day 1 and that this increase was significantly correlated with the Injury Severity Score (ISS) and interleukin-6 (IL-6). Multivariate logistic regression analysis showed that early MCP-1, ISS, and IL-6 were independent risk factors for sepsis in severe trauma patients. Incorporation of the early MCP-1 into the ISS can increase the discriminative performance for predicting development of sepsis.Early plasma MCP-1 concentrations can be used to assess the severity of trauma and is correlated with the development of sepsis after severe trauma. The addition of the early MCP-1 levels to the ISS significantly improves its ability to predict development of sepsis.

Pyroptosis plays a pivotal role in sepsis and septic shock in animal studies. However, its clinical significance in pathological conditions has not been well elucidated. This study aimed to evaluate the correlation between the percentage of pyroptotic peripheral blood mononuclear cells (PBMCs) and the clinical index and to investigate the relationship between PBMCs pyroptosis and the development of sepsis in trauma patients. This prospective study was conducted from October 2016 to May 2017 in a comprehensive trauma center. Sixty trauma patients and 10 healthy controls were enrolled. Peripheral blood samples were collected from the patients within 24 hours after injury. The percentages of pyroptotic and apoptotic PBMCs were measured using flow cytometry, and plasma levels of cytokines were evaluated using flow cytometric analysis with a human inflammation 13-plex panel. Trauma patients who developed sepsis had higher percentages of pyroptotic and apoptotic PBMCs at admission. Patients who developed sepsis (n = 33) had higher interleukin (IL)-6, IL-18, and monocyte chemotactic protein-1 (MCP-1) concentrations at admission than patients (n = 27) who did not develop sepsis. The percentage of PBMCs pyroptosis was significantly correlated with injury severity score (ISS), acute physiology and chronic health evaluation (APACHE) II score, IL-10, IL-18, and MCP-1 levels in trauma patients. PBMCs pyroptosis is a better biomarker in predicting the development of sepsis after trauma. This study indicates that the percentage of pyroptotic PBMCs increases during the early phase of trauma and that this increase is significantly correlated with the severity and state of inflammation in trauma patients. PBMCs pyroptosis is a potential marker for predicting the development of sepsis after trauma.