Th17/Treg balance: the bloom and wane in the pathophysiology of sepsis.

Sepsis is a multi-organ dysfunction characterized by an unregulated host response to infection. It is associated with high morbidity, rapid disease progression, and high mortality. Current therapies mainly focus on symptomatic treatment, such as blood volume supplementation and antibiotic use, but their effectiveness is limited. Th17/Treg balance, based on its inflammatory property, plays a crucial role in determining the direction of the inflammatory response and the regression of organ damage in sepsis patients. This review provides a summary of the changes in T-helper (Th) 17 cell and regulatory T (Treg) cell differentiation and function during sepsis, the heterogeneity of Th17/Treg balance in the inflammatory response, and the relationship between Th17/Treg balance and organ damage. Th17/Treg balance exerts significant control over the bloom and wanes in host inflammatory response throughout sepsis.

Matrix metalloproteinase-8 regulates dendritic cell tolerance in late polymicrobial sepsis via the nuclear factor kappa-B p65/ß-catenin pathway.

Background: Tolerogenic dendritic cells (DCs) are associated with poor prognosis of sepsis. Matrix metalloproteinases (MMPs) have been shown to have immunomodulatory effects. However, whether MMPs are involved in the functional reprogramming of DCs is unknown. The study aims to investigate the role of MMPs in sepsis-induced DCs tolerance and the potential mechanisms. Methods: A murine model of late sepsis was induced by cecal ligation and puncture (CLP). The expression levels of members of the MMP family were detected in sepsis-induced tolerogenic DCs by using microarray assessment. The potential roles and mechanisms underlying MMP8 in the differentiation, maturation and functional reprogramming of DCs during late sepsis were assessed both in vitro and in vivo. Results: DCs from late septic mice expressed higher levels of MMP8, MMP9, MMP14, MMP19, MMP25 and MMP27, and MMP8 levels were the highest. MMP8 deficiency significantly alleviated sepsis-induced immune tolerance of DCs both in vivo and in vitro. Adoptive transfer of MMP8 knockdown post-septic bone marrow-derived DCs protected mice against sepsis-associated lethality and organ dysfunction, inhibited regulatory T-cell expansion and enhanced Th1 response. Furthermore, the effect of MMP8 on DC tolerance was found to be associated with the nuclear factor kappa-B p65/ß-catenin pathway. Conclusions: Increased MMP8 levels in septic DCs might serve as a negative feedback loop, thereby suppressing the proinflammatory response and inducing DC tolerance.

Risk model for predicting mortality in patients with necrotizing soft tissue infections in the intensive care unit.

BACKGROUND: The goal of this study is to look into the factors that lead to death in patients with necrotizing soft tissue infections（NSTIs） in the intensive care unit and create a mortality risk model. METHODS: The clinical data of 106 patients with necrotizing soft tissue infections admitted to intensive care unit(ICU) of the First Affiliated Hospital of Wenzhou Medical University between January 2008 and December 2021 were retrospectively analyzed. Univariate analysis and multivariate analysis were performed to evaluate the risk factors impacting patient mortality. The regression coefficient in binary logistic regression analysis was converted into the item score in the model, and then the model score of each patient was calculated. Finally, an ROC curve was constructed to evaluate the efficiency of the model for predicting mortality. Thirteen patients with NSTIs admitted to ICU between January 2022 and November 2022 were used to validate the model. RESULTS: The death group had 44 patients, while the survival group had 62 patients. The overall mortality was 41.5%. Binary logistic regression analysis showed that risk factors for mortality were age≥ 60 years(OR:4.419; 95%CI:1.093-17.862; P = 0.037), creatinine ≥ 132µmol/L(OR:11.166; 95%CI:2.234-55.816; P = 0.003), creatine kinase ≥ 1104 U/L(OR:4.019; 95%CI:1.134-14.250; P = 0.031), prothrombin time ≥ 24.4 s(OR:11.589; 95%CI:2.510-53.506; P = 0.002), and invasive mechanical ventilation (OR:17.404; 95%CI:4.586-66.052; P＜0.000). The AUC of the model for predicting mortality was 0.940 (95% CI:0.894-0.986). When the cut-off value for the model was 4 points, the sensitivity was 95.5% and the specificity was 83.9%. CONCLUSION: The death risk model in this study for NSTIs patients in the intensive care unit shows high sensitivity and specificity. Patients with a score of ≥ 4 points have a higher risk of mortality.

Administration of protopine prevents mitophagy and acute lung injury in sepsis.

Introduction: Sepsis is a severe life-threatening infection that induces a series of dysregulated physiologic responses and results in organ dysfunction. Acute lung injury (ALI), the primary cause of respiratory failure brought on by sepsis, does not have a specific therapy. Protopine (PTP) is an alkaloid with antiinflammatory and antioxidant properties. However, the function of PTP in septic ALI has not yet been documented. This work sought to investigate how PTP affected septic ALI and the mechanisms involved in septic lung damage, including inflammation, oxidative stress, apoptosis, and mitophagy. Methods: Here, we established a mouse model induced by cecal ligation and puncture (CLP) and a BEAS-2B cell model exposed to lipopolysaccharide (LPS). Results: PTP treatment significantly reduced mortality in CLP mice. PTP mitigated lung damage and reduced apoptosis. Western blot analysis showed that PTP dramatically reduced the expression of the apoptosis-associated protein (Cleaved Caspase-3, Cyto C) and increased Bcl-2/Bax. In addition, PTP decreased the production of inflammatory cytokines (IL-6, IL-1ß, TNF-α), increased glutathione (GSH) levels and superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) levels. Meanwhile, PTP significantly reduced the expression of mitophagy-related proteins (PINK1, Parkin, LC-II), and downregulated mitophagy by transmission electron microscopy. Additionally, the cells were consistent with animal experiments. Discussion: PTP intervention reduced inflammatory responses, oxidative stress, and apoptosis, restored mitochondrial membrane potential, and downregulated mitophagy. The research shows that PTP prevents excessivemitophagy and ALI in sepsis, suggesting that PTP has a potential role in the therapy of sepsis.

SUPPLEMENTATION WITH NICOTINAMIDE RIBOSIDE ATTENUATES T CELL EXHAUSTION AND IMPROVES SURVIVAL IN SEPSIS.

ABSTRACT: T cell exhaustion is the main cause of sepsis-induced immunosuppression and is associated with the poor prognosis. Nicotinamide adenine dinucleotide (NAD + ) is well known for its anti-aging effect, but its role in sepsis-induced T cell exhaustion remains to be elucidated. In the present study, using a classic septic animal model, we found that the levels of NAD + and its downstream molecule, which is sirtuins 1 (SIRT1), in T cells in sepsis were decreased. Supplementation with nicotinamide ribose (NR), the precursor of NAD + , right after cecal ligation and puncture significantly increased the levels of NAD + and SIRT1. Supplementation with NR alleviated the depletion of mononuclear cells and T lymphocytes in spleen in sepsis and increased the levels of CD3 + CD4 + and CD3 + CD8 + T cells. Interestingly, both Th1 and Th2 cells were expanded after NR treatment, but the balance of Th1/Th2 was partly restored. Nicotinamide ribose also inhibited the regulatory T cells expansion and programmed cell death 1 expression in CD4 + T cells in sepsis. In addition, the bacteria load, organ damage (lung, heart, liver, and kidney), and the mortality of septic mice were reduced after NR supplementation. In summary, these results demonstrate the beneficial effect of NR on sepsis and T cell exhaustion, which is associated with NAD + /SIRT1 pathway.

Mutual promotion of mitochondrial fission and oxidative stress contributes to mitochondrial-DNA-mediated inflammation and epithelial-mesenchymal transition in paraquat-induced pulmonary fibrosis.

BACKGROUND: Pulmonary fibrosis (PF) is one of the main causes of death in patients with paraquat (PQ) poisoning. This study aimed to evaluate the relationship between mitochondrial fission and oxidative stress in PQ-induced epithelial-mesenchymal transition (EMT) and PF. METHODS: C57BL/6 mice and MLE-12 cells were exposed to PQ to construct a PF model in vivo and in vitro. Histological changes in the lungs were examined by hematoxylin and eosin (H&E) staining. Mitochondrial morphology was detected by MitoTracker® Deep Red FM or transmission electron microscopy (TEM). Western blotting and immunofluorescence were used to determine the expression of protein. The migration ability of the cells was detected by the cell scratch test. Mitochondrial DNA (mtDNA) levels were assessed by real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was applied to detect cytokine levels. Superoxide dismutase (SOD) activity and the levels of glutathione (GSH) and malondialdehyde (MDA) were detected by chemichromatometry. RESULTS: PQ exposure caused EMT and PF in vivo and in vitro. PQ destroyed mitochondrial structure and enhanced the expression of dynamin-related protein 1 (Drp1), which were accompanied by oxidative stress. Inhibiting mitochondrial fission using mitochondrial division inhibitor-1 (Mdivi-1), a selective inhibitor of Drp1, attenuated PQ-induced EMT and oxidative damage. Treatment with N-acetyl-L-cysteine (NAC), an antioxidant, reduced Drp1 expression, attenuated mitochondrial structure damage and inhibited PQ-induced EMT and PF. Both Mdivi-1 and NAC treatment markedly suppressed mtDNA release, the expression of Toll-like receptor 9 (TLR9) and phosphorylation (P)-NF-κB p65 as well as cytokines (interleukin 6 [IL-6], interleukin-1ß [IL-1ß], and tumor necrosis factor-α [TNF-α]) production. CONCLUSION: Mutual promotion of mitochondrial fission and oxidative stress contributes to EMT in PQ-induced PF, which is associated with the mtDNA/TLR9/NF-κB pathway.

Berberine Alleviates Acute Lung Injury in Septic Mice by Modulating Treg/Th17 Homeostasis and Downregulating NF-κB Signaling.

Purpose: A common complication of sepsis is acute lung injury (ALI), which is associated with an acute onset, rapid disease changes, and high mortality. Regulatory T (Treg) and T helper 17 (Th17) cells comprise CD4+ T cell subsets, which strongly influence inflammation during ALI. In this study, we investigated the effect of berberine (BBR), an antioxidant, anti-inflammatory, and immunomodulatory drug, on the inflammatory response and immune state in mice with sepsis. Methods: A mouse model of cecal ligation and puncture (CLP) was established. The mice were intragastrically administered 50 mg/kg BBR. We used histological techniques to evaluate inflammatory tissue injury and flow cytometry for analyzing Treg/Th17 levels. We also assessed NF-κB signaling pathways by Western blotting assays and immunofluorescence staining. Enzyme-linked immunosorbent assay (ELISA) was performed to measure the content of cytokines. Results: Treatment with BBR considerably mitigated lung injury while improving survival, post-cecal ligation, and puncture (CLP). Treatment with BBR ameliorated pulmonary edema and hypoxemia in septic mice and inhibited the NF-κB signaling pathway. BBR also increased Treg cells and decreased Th17 proportions in the spleen and lung tissue of CLP-treated mice. Blocking Treg cells weakened the protective effect of BBR on sepsis-associated lung injury. Conclusion: Overall, these results suggested that BBR is a potential therapeutic agent for sepsis.

A new criteria for acute on preexisting kidney dysfunction in critically ill patients.

Critically ill patients with preexisting kidney dysfunction (PKD) are at high risk for acute kidney injury (AKI). Nevertheless, there is no criteria for screening and classifying AKI in patients with PKD. In this study, after assessing relationship between the change in SCr from baseline and in-hospital mortality, a new criteria, named APKD, for identifying AKI in PKD was proposed. APKD defined AKI in critically ill patients with PKD as an absolute increase of ≥ 0.2 mg/dL in SCr within 48 h or an increase in SCr ≥ 1.1 times over baseline within 7 d. APKD detected more AKI among PKD patients compared with the other criteria. Additionally, the AKI patients identified by APKD but missed by the other criteria had higher mortality than those without AKI. APKD shows higher sensitivities than KDIGO criteria in predicating in-hospital mortality. APKD, but not the KDIGO, is effective for staging the severity of AKI in patients with PKD. In conclusion, APKD is more effective in screening and classifying AKI in critically ill patients with PKD compared with the earlier criteria, and it may helpful in guiding clinical treatment and predicting prognosis.

PINK1 protects against dendritic cell dysfunction during sepsis through the regulation of mitochondrial quality control.

BACKGROUND: Dendritic cell (DC) dysfunction plays a central role in sepsis-induced immunosuppression. Recent research has indicated that collective mitochondrial fragmentation contributes to the dysfunction of immune cells observed during sepsis. PTEN-induced putative kinase 1 (PINK1) has been characterized as a guide for impaired mitochondria that can keep mitochondrial homeostasis. However, its role in the function of DCs during sepsis and the related mechanisms remain obscure. In our study, we elucidated the effect of PINK1 on DC function during sepsis and its underlying mechanism of action. METHODS: Cecal ligation and puncture (CLP) surgery and lipopolysaccharide (LPS) treatment were used as in vivo and in vitro sepsis models, respectively. RESULTS: We found that changes in mitochondrial PINK1 expression of DCs paralleled changes in DC function during sepsis. The ratio of DCs expressing MHC-II, CD86, and CD80, the mRNAs level of dendritic cells expressing TNF-α and IL-12, and the level of DC-mediated T-cell proliferation were all decreased, both in vivo and in vitro during sepsis, when PINK1 was knocked out. This suggested that PINK1 knockout prevented the function of DCs during sepsis. Furthermore, PINK1 knockout inhibited Parkin RBR E3 ubiquitin protein (Parkin)-dependent mitophagy and enhanced dynamin-related protein 1 (Drp1)-related mitochondrial fission, and the negative effects of PINK1 knockout on DC function following LPS treatment were reversed by Parkin activation and Drp1 inhibitor. Knockout of PINK1 also increased apoptosis of DCs and the mortality of CLP mice. CONCLUSION: Our results indicated that PINK1 protected against DC dysfunction during sepsis through the regulation of mitochondrial quality control.

Orai1 overexpression improves sepsis-induced T-lymphocyte immunosuppression and acute organ dysfunction in mice.

Immune paralysis induced by sepsis, especially dysfunction of CD4+ T cells, leads to an increased risk of infection. In sepsis, abnormal differentiation of T lymphocytes is associated with multiorgan dysfunction syndrome. In T lymphocytes, the Orai1/nuclear factor of activated T Cells (NFAT) pathway is a critical mediator of infection, inflammation, and autoimmunity. In this study, we confirmed immunosuppression of splenic CD4+ T cells and abnormal differentiation of T lymphocytes in septic mice. Furthermore, we found that the Orai1/NFAT signaling pathway was inhibited in septic mice; however, the overexpression of Orai1 not only improved immune function of T cells in sepsis but also reduced the mortality and organ damage in septic mice. Moreover, the overexpression of Orai1 could reverse the increases in the numbers of T regulatory and T helper 17 cells in septic mice. These data suggest that the Orai1-mediated NFAT signaling pathway can improve sepsis-induced T-lymphocyte immunosuppression and acute organ dysfunction.

[Value of vascular endothelial-cadherin in evaluating the severity of patients with sepsis].

OBJECTIVE: To explore the value of vascular endothelial-cadherin (VE-cad) in evaluating the severity of sepsis. METHODS: A prospective study was conducted to select 85 patients with sepsis treated in the emergency ward of the First Affiliated Hospital of Wenzhou Medical University from June 1, 2015 to November 1, 2017. The gender, age, medical history, first infection site, number of affected organs, laboratory indexes, acute physiology and chronic health evaluation II (APACHE II), simplified acute physiology score II (SAPS II), sequential organ failure assessment (SOFA) and the total length of stay, emergency intensive care unit (EICU) length of stay, 28-day at admission and survival during hospitalization were measured, and the VE-cad level within 24 hours at admission was measured. The patients were divided into sepsis group and septic shock group according to the progress of the disease. The patients were divided into multiple organ dysfunction syndrome (MODS) group and non MODS group according to whether they were accompanied by MODS. The differences of the above indexes in patients with different disease progression, MODS and different prognosis were analyzed and compared. The receiver operator characteristic curve (ROC curve) was drawn to evaluate the value of VE-cad in evaluating the severity of sepsis. RESULTS: A total of 85 patients were included, mainly respiratory tract infection. Among them, 38 cases were sepsis and 47 cases were septic shock, 39 cases had MODS, 46 cases had no MODS, 64 cases survived and 21 cases died within 28 days after admission. Compared with sepsis group, the number of affected organs in septic shock group was greater [3 (2, 4) vs. 1 (0, 2)], APACHE II score [13 (10, 21) vs. 7 (5, 12)], SAPS II score [35 (31, 55) vs. 7 (5, 12)], SOFA score [7.0 (5.0, 10.0) vs. 3.0 (0, 5.0)], blood lactic acid [Lac (mmol/L): 3.5 (2.4, 6.2) vs. 1.9 (1.2, 2.2)], C-reactive protein [CRP (mg/L): 90.0 (58.1, 90.0) vs. 50.5 (38.0,90.0)] and VE-cad levels [mg/L: 1.427 (1.141, 2.150) vs. 1.195 (0.901, 1.688)] were significantly increased, while platelet count [PLT (×109/L): 113.4±67.2 vs. 202.5±109.5] and hemoglobin (Hb) levels (g/L: 106.3±36.3 vs. 118.6±18.0) were significantly decreased (all P < 0.05). Compared with non MODS group, APACHE II score [14 (10, 22) vs. 8 (6, 13)], SAPS II score [36 (32, 56) vs. 29 (24, 35)], SOFA score (7.9±3.9 vs. 4.0±3.8), in-hospital mortality [53.8% (21/39) vs. 0% (0/46)], Lac [mmol/L: 3.1 (2.3, 6.3) vs. 2.1 (1.4, 4.6)] and VE-cad levels [mg/L: 1.427 (1.156, 1.937) vs. 1.195 (0.897, 1.776)] in MODS group were significantly higher, the length of stay in EICU was significantly longer [days: 6 (3, 12) vs. 3 (0, 7)], and the PLT level was significantly lower (×109/L: 118.2±80.0 vs. 182.5±104.0, all P < 0.05). Compared with the death group, the number of affected organs in the survival group was fewer [2 (1, 3) vs. 3 (1, 5)], APACHE II score [9 (6, 13) vs. 21 (13, 25)], SAPS II score [31 (25, 36) vs. 55 (35, 63)] and SOFA score (4.7±3.7 vs. 8.9±4.5) were significantly reduced, and the length of stay in EICU [days: 4 (1, 8) vs. 8 (3, 15)] was significantly shorter (all P < 0.05). ROC curve analysis showed that area under the ROC curve (AUC) of VE-cad, SOFA score and VE-cad combined with SOFA score in evaluating the severity of sepsis were 0.632 [95% confidence interval (95%CI) was 0.513-0.750], 0.830 (95%CI was 0.744-0.916) and 0.856 (95%CI was 0.779-0.933), respectively. When the cut-off value of VE-cad was 1.240 mg/L, the sensitivity was 68.1% and the specificity was 55.3%, the sensitivity of VE-cad combined with SOFA score was 85.1%, the specificity was 73.7%. CONCLUSIONS: VE-cad has a certain evaluation value for the severity of sepsis, and the evaluation value of VE-cad combined with SOFA score is better than that of VE-cad single index.

Vesicle transport related protein Synaptotagmin-1 mediates paraquat transport to antagonize paraquat toxicity.

In this study, A549/PQ cells with moderate resistance to paraquat (PQ) were obtained by treating A549 cells with PQ, their growth rate was slowed down, the accumulation concentration of PQ and the levels of growth inhibition, injury and early apoptosis induced by PQ were significantly lower than those of parental A549 cells. Microarray screening and RT-qPCR detection found that Synaptotagmin-1 (SYT1) expression in drug-resistant cells was significantly increased, and PQ further enhanced its expression. After inhibiting SYT1 expression in A549/PQ cells, cell viability, intracellular PQ concentration and the expression of Bcl-2, SNAP25 and RAB26 were significantly reduced, while the mortality, early apoptosis rate and Bax expression were significantly increased. In vivo experiments also further showed that PQ promoted the expression of SYT1, SNAP25 and RAB26 in PQ-poisoned mice; when inhibiting SYT1 expression, PQ concentration in lung tissues was significantly increased, and the levels of lung injury and apoptosis were also significantly enhanced, while the expression of SNAP25 and RAB26 was significantly reduced. This indicates that PQ poisoning leads to compensatory up-regulation of vesicle transport related proteins such as SYT1 in vivo, thereby promoting PQ transmembrane transport, and then reducing the pulmonary accumulation of PQ and PQ-caused lung injury.

CD71+ Erythroid Cell Expansion in Adult Sepsis: Potential Causes and Role in Prognosis and Nosocomial Infection Prediction.

BACKGROUND: Immune suppression contributes to nosocomial infections (NIs) and poor prognosis in sepsis. Recent studies revealed that CD71+ erythroid cells had unappreciated immunosuppressive functions. This study aimed to investigate the values of CD71+ erythroid cells (CECs) in predicting NIs and prognosis among adult septic patients. The potential factors associated with the expansion of CECs were also explored. METHODS: In total, 112 septic patients and 32 critically ill controls were enrolled. The frequencies of CD71+ cells, CD71+CD235a+ cells, and CD45+ CECs were measured by flow cytometry. The associations between CECs and NIs and 30-day mortality were assessed by ROC curve analysis and Cox and competing-risk regression models. Factors associated with the frequency of CECs were identified by linear regression analysis. RESULTS: The percentage of CD71+ cells, CECs, and CD45+ CECs were higher in septic patients than critically ill controls. In septic patients, the percentages of CD71+ cells, CECs, and CD45+ CECs were associated with NI development, while CD71+ cells and CECs were independently associated with 30-day mortality. Linear regression analysis showed that the levels of interleukin (IL)-6 and interferon (IFN)-γ were positively associated with the frequencies of CD71+ cells, CECs, and CD45+ CECs, while IL-10 was negatively associated with them. Additionally, the levels of red blood cells (RBCs) were negatively associated with the percentage of CD45+ CECs. CONCLUSIONS: CECs were expanded in sepsis and can serve as independent predictors of the development of NI and 30-day mortality. Low levels of RBCs and high levels of IL-6 and IFN-γ may contribute to the expansion of CECs in sepsis. TRIAL REGISTRATION: ChiCTR, ChiCTR1900024887. Registered 2 August 2019, http://www.chictr.org.cn/showproj.aspx?proj=38645.

Pink1/Parkin-Mediated Mitophagy Regulated the Apoptosis of Dendritic Cells in Sepsis.

Dendritic cells (DCs) are vital antigen-presenting cells (APCs) in the immune system, whose apoptosis is closely related to the development of sepsis. Mitophagy is one of the necessary forms of selective autophagy that removes damaged or dysfunctional mitochondria to regulate immunity and inflammation. However, its effect on the apoptosis of DC in sepsis remains unknown. Here, we showed that sepsis activated the apoptosis and mitophagy of DC, and mitophagy had an anti-apoptotic effect on sepsis-induced DC apoptosis. In this study, we used cecal ligation and puncture (CLP) to simulate the pathophysiological state of sepsis. Apoptosis and mitophagy of DC were significantly enhanced in CLP mice compared with controls, and in the Pink1-KO (Pink1-knockout) mice CLP model, the level of apoptosis in DC was further increased while the level of mitophagy was decreased. In addition, more severe mitochondrial dysfunction was exhibited in DC of Pink1-KO mice CLP model compared to wild-type (WT) mice. The results suggest that Pink1/Parkin-mediated mitophagy is activated during sepsis and has an anti-apoptotic effect on DC, which regulates immune functions.

Ginkgolic acid promotes inflammation and macrophage apoptosis via SUMOylation and NF-κB pathways in sepsis.

Background: Excessive inflammation and increased apoptosis of macrophages contribute to organ damage and poor prognosis of sepsis. Ginkgolic acid (GA) is a natural constituent extracted from the leaves of Ginkgo biloba, that can regulate inflammation and apoptosis. The present study aims to investigate the potential effect of GA in treating sepsis and its possible mechanisms. Materials and methods: Here, a classic septic mice model and a lipopolysaccharide (LPS)-induced RAW 264.7 inflammation model were established. Cytokines in serum and culture supernatant were detected by ELISA, and the mRNA levels of them were examined by PCR. Hematoxylin and eosin (H&E) staining was performed to determine histopathological changes in liver, lung and kidney. Bacterial burden in the blood, peritoneal lavage fluids (PLFs) and organs were observed on Luria-Bertani agar medium. Flow cytometry and western blotting was used to detect apoptosis and the expression level of apoptosis related molecules, respectively. Moreover, the levels of SUMOylation were detected by western blotting. The activity of NF-κB p65 was assessed by immunofluorescence staining and western blotting. Results: The result showed that GA promoted inflammatory responses, reduced bacterial clearance, aggravated organ damage, and increased mortality in septic mice. GA increased apoptosis in peritoneal macrophages (PMs) and RAW 264.7 cells. Meanwhile, GA inhibited SUMOylation and increased the nuclear translocation of NF-κB p65 as well as its phosphorylation level. Conclusion: Collectively, GA promotes inflammation and macrophage apoptosis in sepsis, which may be mediated by inhibiting the SUMOylation process and increasing NF-κB p65 activity.

Emodin alleviates LPS-induced myocardial injury through inhibition of NLRP3 inflammasome activation.

Myocardial injury and cardiovascular dysfunction are serious consequences of sepsis and contribute to high mortality. Currently, the pathogenesis of myocardial injury in sepsis is still unclear, and therapeutic approaches are limited. In this study, we investigated the protective effect of emodin on septic myocardial injury and the underlying mechanism. Lipopolysaccharide (LPS)-induced C57BL/6 mice and cardiomyocytes were used as models of sepsis in vivo and in vitro, respectively. The results showed that emodin alleviated cardiac dysfunction, myocardial injury and improved survival rate in LPS-induced septic mice. Emodin attenuated the levels of inflammatory cytokines and cardiac inflammation induced by LPS. Emodin reduced NOD-like receptor protein 3 (NLRP3) and Gasdermin D (GSDMD) expression in the heart tissue of LPS-induced septic mice. In vitro, emodin alleviated LPS-induced cell injury and inflammation in cardiomyocytes by inhibiting NLRP3 inflammasome activation. In addition, an NLRP3 inhibitor was used to further confirm the function of the NLRP3 inflammasome in LPS-induced myocardial injury. Taken together, our findings suggest that emodin improves LPS-induced myocardial injury and cardiac dysfunction by alleviating the inflammatory response and cardiomyocyte pyroptosis by inhibiting NLRP3 inflammasome activation, which provides a feasible strategy for preventing and treating myocardial injury in sepsis.

Protective Effects of Chitosan-Bilirubin Nanoparticles Against Ethanol-Induced Gastric Ulcers.

PURPOSE: Gastric ulcers (GU) are a disease of the gastrointestinal tract that can be caused by excessive alcohol consumption and heavy use of nonsteroidal anti-inflammatory drugs. GU manifests predominantly as pathological damage, such as extensive inflammatory erosion and superficial bleeding of the gastric mucosa. Oxidative stress damage and the inflammatory response are now considered important predisposing factors for GU, suggesting that antioxidant and anti-inflammatory drugs could be treatments for GU. Nanoparticle drug carriers offer many advantages over conventional drugs, such as improved drug efficiency, increased drug stability, and increased half-life. METHODS: We designed chitosan-bilirubin conjugate (CS-BR) nanoparticles and assessed the anti-inflammatory and antioxidant abilities of CS-BR in gastric epithelial cells. Then, we evaluated the intragastric retention time and the anti-ulcer effects of CS-BR in vivo. RESULTS: The in vitro data showed that CS-BR nanoparticles protect gastric epithelial cells against oxidative/inflammatory injury. The in vivo study demonstrated that CS-BR nanoparticles accumulate permanently in the stomach and exert powerful antioxidant and anti-inflammatory effects against GU. CONCLUSION: This study applied bilirubin to the treatment of GU and confirmed that CS-BR nanoparticles are effective at alleviating acute GU in an experimental model. The findings provide innovative ideas for prophylaxis against or treatment of GU.

Arterial oxygen pressure targets in critically ill patients: Analysis of a large ICU database.

BACKGROUND: Providing supplemental oxygen is common in the management of critically ill patients, yet the optimal oxygen regimen remains unclear. OBJECTIVES: To explore the optimal range of PaO2 in critically ill patients. METHODS: This is a retrospective study conducted in the Medical Information Mart for Intensive Care III (MIMIC-III) database. The patients with a least 48 h of oxygen therapy were included. Nonlinear regression was used to analyze the association between PaO2 and mortality. We derived an optimal range of PaO2 and evaluated the association between the proportion of PaO2 measurements within this range and mortality. RESULTS: In total, 8401 patients were included in the study. A J-shaped relationship was observed between median PaO2 and hospital mortality. Compared with the reference group of 100-120 mmHg, patients with values of 80-100 mmHg and 120-140 mmHg had higher hospital mortality (adjusted odds ratio [aOR], 1.23; 95% CI, 1.05-1.43 and 1.29; 95%CI, 1.08-1.54, respectively). Similarly, mortality rates were significantly higher for PaO2 <80 mmHg and ≥140 mmHg (aOR, 1.97; 95%CI, 1.58-2.45 and 1.42; 95%CI, 1.19-1.69, respectively). Patients spent a greater proportion of time within 100-120 mmHg tended to have a lower mortality rate. CONCLUSION: Among critically ill patients, the relationship between median PaO2 and hospital mortality was J-shaped. The lowest rates of mortality was observed in those with PaO2 levels within 100 to 120 mmHg.

Partial Depletion of Regulatory T Cells Enhances Host Inflammatory Response Against Acute Pseudomonas aeruginosa Infection After Sepsis.

Immune dysfunction contributes to secondary infection and worse outcomes in sepsis. Regulatory T cells (Tregs) have been implicated in sepsis-induced immunosuppression. Nevertheless, the role of Tregs in secondary infection after sepsis remains to be determined. In the present study, a two-hit model which mimics clinical conditions was used and the potential role of Tregs in secondary Pseudomonas aeruginosa infection post-sepsis was investigated. Results showed that mice were susceptible to secondary P. aeruginosa infection 3 days, but not 7 days, post-cecal ligation and puncture (CLP). The levels of IL-17A, IL-1ß, and IL-6 remained low in CLP mice after P. aeruginosa infection, while the levels of IL-10 increased significantly. Additionally, increased number of Tregs in both lung and spleen was observed in "two-hit" mice. Injection with PC61 (anti-CD25) mAb reduced the number of Tregs by 50% in spleen and 60% in lung of septic mice. This partial depletion of Tregs elevated IL-17A, IL-1ß, and IL-6 production and decreased IL-10 levels in septic mice with P. aeruginosa infection, leading to lower bacterial load, attenuation of lung injury, and improvement of survival. The present findings demonstrate that Tregs play a crucial role in secondary P. aeruginosa infection after sepsis by modulating the inflammatory response.