The association between blood glucose levels and matrix-metalloproteinase-9 in early severe sepsis and septic shock

Neutral Sphingomyelinase 2 Inhibition Limits Hepatic Steatosis and Inflammation

Non-alcoholic fatty liver disease (NAFLD) is manifested by hepatic steatosis, insulin resistance, hepatocyte death, and systemic inflammation. Obesity induces steatosis and chronic inflammation in the liver. However, the precise mechanism underlying hepatic steatosis in the setting of obesity remains unclear. Here, we report studies that address this question. After 14 weeks on a high-fat diet (HFD) with high sucrose, C57BL/6 mice revealed a phenotype of liver steatosis. Transcriptional profiling analysis of the liver tissues was performed using RNA sequencing (RNA-seq). Our RNA-seq data revealed 692 differentially expressed genes involved in processes of lipid metabolism, oxidative stress, immune responses, and cell proliferation. Notably, the gene encoding neutral sphingomyelinase, SMPD3, was predominantly upregulated in the liver tissues of the mice displaying a phenotype of steatosis. Moreover, nSMase2 activity was elevated in these tissues of the liver. Pharmacological and genetic inhibition of nSMase2 prevented intracellular lipid accumulation and TNFα-induced inflammation in in-vitro HepG2-steatosis cellular model. Furthermore, nSMase2 inhibition ameliorates oxidative damage by rescuing PPARα and preventing cell death associated with high glucose/oleic acid-induced fat accumulation in HepG2 cells. Collectively, our findings highlight the prominent role of nSMase2 in hepatic steatosis, which could serve as a potential therapeutic target for NAFLD and other hepatic steatosis-linked disorders.

Comprehensive analysis of senescence-associated genes in sepsis based on bulk and single-cell sequencing data

Background: Sepsis is a pathological state resulting from dysregulated immune response in host during severe infection, leading to persistent organ dysfunction and ultimately death. Senescence-associated genes (SAGs) have manifested their potential in controlling the proliferation and dissemination of a variety of diseases. Nevertheless, the correlation between sepsis and SAGs remains obscure and requires further investigation. Methods: Two RNA expression datasets (GSE28750 and GSE57065) specifically related to sepsis were employed to filter hub SAGs, based on which a diagnostic model predictive of the incidence of sepsis was developed. The association between the expression of the SAGs identified and immune-related modules was analyzed employing Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) and Microenvironment Cell Populations-counter (MCP-counter) analysis. The identified genes in each cohort were clustered by unsupervised agreement clustering analysis and weighted gene correlation network analysis (WGCNA). Results: A diagnostic model for sepsis established based on hub genes (IGFBP7, GMFG, IL10, IL18, ETS2, HGF, CD55, and MMP9) exhibited a strong clinical reliability (AUC = 0.989). Sepsis patients were randomly assigned and classified by WGCNA into two clusters with distinct immune statuses. Analysis on the single-cell RNA sequencing (scRNA-seq) data revealed high scores of SAGs in the natural killer (NK) cells of the sepsis cohort than the healthy cohort. Conclusion: These findings suggested a close association between SAGs and sepsis alterations. The identified hub genes had potential to serve as a viable diagnostic marker for sepsis.

Crosstalk between septic shock and venous thromboembolism: a bioinformatics and immunoassay analysis

Background

Herein, we applied bioinformatics methods to analyze the crosstalk between septic shock (SS) and venous thromboembolism (VTE), focusing on the correlation with immune infiltrating cells.

Methods

Expression data were obtained from the Gene Expression Omnibus (GEO) database, including blood samples from SS patients (datasets GSE64457, GSE95233, and GSE57065) and VTE patients (GSE19151). We used the R package "limma" for differential expression analysis (p value<0.05,∣logFC∣≥1). Venn plots were generated to identify intersected differential genes between SS and VTE and conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) Enrichment analysis. The protein-protein interaction (PPI) network of intersected genes was constructed by Cytoscape software. The xCell analysis identified immune cells with significant changes in VTE and SS and correlated them with significant molecular pathways of crosstalk. Finally, we validated the mRNA expression of crosstalk genes by qPCR, while Matrix Metalloprotein-9 (MMP-9) protein levels were assessed through Western blotting (WB) and Immunohistochemistry (IHC) in human umbilical vein endothelial cells (HUVECs) and mice.

Results

In the present study, we conducted a comparison between 88 patients with septic shock and 55 control subjects. Additionally, we compared 70 patients with venous thromboembolism to 63 control subjects. Twelve intersected genes and their corresponding three important molecular pathways were obtained: Metabolic, Estrogen, and FOXO signaling pathways. The resulting PPI network has 194 nodes and 388 edges. The immune microenvironment analysis of the two diseases showed that the infiltration levels of M2 macrophages and Class-switched memory B cells were correlated with the enrichment scores of metabolic, estrogen, and FOXO signaling pathways. Finally, qPCR confirmed that the expression of MMP9, S100A12, ARG1, SLPI, and ANXA3 mRNA in the SS with VTE group was significantly elevated. WB and IHC experiments revealed that MMP9 protein was significantly elevated in the experimental group.

Conclusion

Metabolic, estrogen, and FOXO pathways play important roles in both SS and VTE and are related to the immune cell microenvironment of M2 macrophages and Class-switched memory B cells. MMP9 shows promise as a biomarker for diagnosing sepsis with venous thrombosis and a potential molecular target for treating this patient population.

Sepsis-associated encephalopathy: From pathophysiology to clinical management

Sepsis-associated encephalopathy, which presents as delirium and coma, is a significant complication of sepsis characterized by acute brain dysfunction. The presence of inflammatory pathological changes in the brain of sepsis patients and animal models has been recognized since the 1920 s, initially attributed to the entry of microbial toxins into the brain. In the early 2000 s, attention shifted towards the impact of oxidative stress, the cholinergic system, and cytokines on brain function following sepsis onset. More recently, sepsis-associated encephalopathy has been defined as a diffuse brain dysfunction not directly caused by pathogenic infection of the brain. Currently, there is no evidence-based standard for diagnosing sepsis-associated encephalopathy, and clinical management is primarily focused on symptomatic and supportive measures. This review aims to explore the pathophysiology of sepsis-associated encephalopathy and establish the connection between pathophysiological mechanisms and clinical characteristics. We hope that this work will spark the interest of researchers from various fields and contribute to the advancement of sepsis-associated encephalopathy research.

Paper-Based Biosensor for the Detection of Sepsis Using MMP-9 Biomarker in FIP Mice Model

Sepsis is an immune response to a microbial invasion that causes organ injury and dysfunction due to a systemic inflammatory response. Sepsis is a serious, life-threatening condition and a widely recognized global health challenge. Given its high death rate, it is critical to diagnose sepsis and start treatment as early as possible. There is an urgent need for a sensitive and rapid screening method for detecting sepsis. In this study, we investigated the use of MMP-9 as a biomarker for sepsis. A colorimetric paper-based biosensor was used for the detection of MMP-9 utilizing peptide-magnetic nanoparticle conjugates. The method is based on the cleavage of the MMP-9-specific peptide by the protease leading to the detaching of the magnetic beads from the sensor surface and changing of color. A fecal intraperitoneal (FIP) challenge was used to induce sepsis in mice, and an MMP-9 secretion was measured by taking blood and Bronchoalveolar Lavage (BAL) fluid samples at 1 h, 2 h, 4 h, and 20 h (early sepsis) post-challenge intervals. The results of the paper-based sensor for the detection of MMP-9 levels in blood samples and BAL samples were compared with ELISA and Western Blot. We found that both blood and BAL levels of MMP-9 increased immediately and could be detected as early as 1 h in FIP mice post-challenge. Our work adds evidence to the assertion that MMP-9 is a reliable biomarker for the detection of sepsis at early stages.

Reduced inhibitory and excitatory input onto parvalbumin interneurons mediated by perineuronal net might contribute to cognitive impairments in a mouse model of sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is commonly defined as diffuse brain dysfunction and can manifest as delirium to coma. Accumulating evidence has suggested that perineuronal net (PNN) plays an important role in the modulation of the synaptic plasticity of central nervous system. We here investigated the role of PNN in SAE induced by lipopolysaccharide (LPS) injection. Behavioral tests were performed by open field, Y-maze, and fear conditioning tests at the indicated time points. The densities of vesicular γ-aminobutyric acid transporter, vesicular glutamate transporter 1, PNN, and parvalbumin (PV) in the hippocampus were evaluated by immunofluorescence. Matrix metalloproteinases-9 (MMP-9) expression and its activity were detected by Western blot and gel zymography, respectively. Local field potential was recorded by in vivo electrophysiology. LPS-treated mice displayed significant cognitive impairments, coincided with activated MMP-9, decreased PNN and PV densities, reduced inhibitory and excitatory input onto PV interneurons enwrapped by PNN, and decreased gamma oscillations in hippocampal CA1. Notably, MMP-9 inhibitor SB-3CT treatment rescued most of these abnormalities. Taken together, our study demonstrates that active MMP-9 mediated PNN remodeling, leading to reduced inhibitory and excitatory input onto PV interneurons and abnormal gamma oscillations in hippocampal CA1, which consequently contributed to cognitive impairments after LPS injection.

Recent insights into the role of defensins in diabetic wound healing

Diabetic wound, one of the most common serious complications of diabetic patients, is an important factor in disability and death. Much of the research on the pathophysiology of diabetic wound healing has long focused on mechanisms mediated by hyperglycemia, chronic inflammation, microcirculatory and macrocirculatory dysfunction. However, recent evidence suggests that defensins may play a crucial role in the development and perpetuation of diabetic wound healing. The available findings suggest that defensins exert a beneficial influence on diabetic wound healing through antimicrobial, immunomodulatory, angiogenic, tissue regenerator effects, and insulin resistance improvement. Therefore, summarizing the existing research progress on defensins in the diabetic wound may present a promising strategy for diabetic patients.

Association of Septic Shock with Mortality in Hospitalized COVID-19 Patients in Wuhan, China

Purpose

Septic shock is a severe complication of COVID-19 patients. We aim to identify risk factors associated with septic shock and mortality among COVID-19 patients.

Methods

A total of 212 COVID-19 confirmed patients in Wuhan were included in this retrospective study. Clinical outcomes were designated as nonseptic shock and septic shock. Log-rank test was conducted to determine any association with clinical progression. A prediction model was established using random forest.

Results

The mortality of septic shock and nonshock patients with COVID-19 was 96.7% (29/30) and 3.8% (7/182). Patients taking hypnotics had a much lower chance to develop septic shock (HR = 0.096, p=0.0014). By univariate logistic regression analysis, 40 risk factors were significantly associated with septic shock. Based on multiple regression analysis, eight risk factors were shown to be independent risk factors and these factors were then selected to build a model to predict septic shock with AUC = 0.956. These eight factors included disease severity (HR = 15, p < 0.001), age > 65 years (HR = 2.6, p=0.012), temperature > 39.1°C (HR = 2.9, p=0.047), white blood cell count > 10 × 10⁹ (HR = 6.9, p < 0.001), neutrophil count > 75 × 10⁹ (HR = 2.4, p=0.022), creatine kinase > 5 U/L (HR = 1.8, p=0.042), glucose > 6.1 mmol/L (HR = 7, p < 0.001), and lactate > 2 mmol/L (HR = 22, p < 0.001).

Conclusions

We found 40 risk factors were significantly associated with septic shock. The model contained eight independent factors that can accurately predict septic shock. The administration of hypnotics could potentially reduce the incidence of septic shock in COVID-19 patients.

Repetitive Intermittent Hyperglycemia Drives the M1 Polarization and Inflammatory Responses in THP-1 Macrophages Through the Mechanism Involving the TLR4-IRF5 Pathway

Repetitive intermittent hyperglycemia (RIH) is an independent risk factor for complications associated with type-2 diabetes (T2D). Glucose fluctuations commonly occur in T2D patients with poor glycemic control or following intensive therapy. Reducing blood glucose as well as glucose fluctuations is critical to the control of T2D and its macro-/microvascular complications. The interferon regulatory factor (IRF)-5 located downstream of the nutrient sensor toll-like receptor (TLR)-4, is emerging as a key metabolic regulator. It remains unclear how glucose fluctuations may alter the IRF5/TLR4 expression and inflammatory responses in monocytes/macrophages. To investigate this, first, we determined IRF5 gene expression by real-time qRT-PCR in the white adipose tissue samples from 39 T2D and 48 nondiabetic individuals. Next, we cultured THP-1 macrophages in hypo- and hyperglycemic conditions and compared, at the protein and transcription levels, the expressions of IRF5, TLR4, and M1/M2 polarization profile and inflammatory markers against control (normoglycemia). Protein expression was assessed using flow cytometry, ELISA, Western blotting, and/or confocal microscopy. IRF5 silencing was achieved by small interfering RNA (siRNA) transfection. The data show that adipose IRF5 gene expression was higher in T2D than nondiabetic counterparts (P = 0.006), which correlated with glycated hemoglobin (HbA1c) (r = 0.47/P < 0.001), homeostatic model assessment of insulin resistance (HOMA-IR) (r = 0.23/P = 0.03), tumor necrosis factor (TNF)-α (r = 0.56/P < 0.0001), interleukin (IL)-1β (r = 0.40/P = 0.0009), and C-C motif chemokine receptor (CCR)-2 (r = 0.49/P < 0.001) expression. IRF5 expression in macrophages was induced/upregulated (P < 0.05) by hypoglycemia (3 mM/L), persistent hyperglycemia (15 mM/L-25 mM/L), and RIH/glucose fluctuations (3-15 mM/L) as compared to normoglycemia (5 mM/L). RIH/glucose fluctuations also induced M1 polarization and an inflammatory profile (CD11c, IL-1β, TNF-α, IL-6, and monocyte chemoattractant protein (MCP)-1) in macrophages. RIH/glucose fluctuations also drove the expression of matrix metalloproteinase (MMP)-9 (P < 0.001), which is a known marker for cardiovascular complication in T2D patients. Notably, all these changes were counteracted by IRF5 silencing in macrophages. In conclusion, RIH/glucose fluctuations promote the M1 polarization and inflammatory responses in macrophages via the mechanism involving TLR4-IRF5 pathway, which may have significance for metabolic inflammation.

Association between Increased Matrix Metalloproteinase-9 (MMP-9) Levels with Hyperglycaemia Incidence in Acute Ischemic Stroke Patients

BACKGROUND:

Hyperglycemia is common in acute stroke patients. Hyperglycemia can induce the production of reactive oxygen species, causing increased activity of matrix metalloproteinase-9 (MMP-9).

AIM:

This study aimed to determine an association between the increased levels of MMP-9 and the incidence of hyperglycemia in acute ischemic stroke patients.

METHODS:

This is a case-control study. Acute ischemic stroke patients admitted to the Stroke Unit of a reference hospital in Yogyakarta, Indonesia was divided into the hyperglycemic and non-hyperglycemic group. Demographic and clinical characteristics of each subject were recorded, and blood levels of MMP-9 were measured. Seventy-one patients were recruited, 40 subjects in the hyperglycemic group and 31 subjects in the non-hyperglycemic group.

RESULTS:

The median levels of blood MMP-9 level in the hyperglycemic and non-hyperglycemic group were 974.37 and 748.48 ng/mL, respectively, and the difference was statistically not significant (95% CI, 191.24-2849.53; p = 0.07). When the calculated cut-off point of 600.99 ng/mL was used, the proportion of patients with higher MMP-9 levels was significantly more in the hyperglycemic group compared with the ones in the non-hyperglycemic group (82.5% and 54.8%, respectively; OR = 3.88; p = 0.011).

CONCLUSION:

We concluded that the proportion of patients with MMP-9 level >600.99 ng/mL was significantly higher in acute ischemic stroke patients with hyperglycemia.

Matrix Metalloproteinase-9 and Tissue Inhibitor of Matrix Metalloproteinase-1 in Sepsis after Major Abdominal Surgery

Background

The role of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in sepsis after major abdominal surgery and sepsis-associated organ dysfunction is unexplored.

Materials and Methods

Fifty-three patients with sepsis after major abdominal surgery were compared to 50 operated and 50 nonoperated controls. MMP-9, TIMP-1, biomarkers of inflammation, kidney and liver injury, coagulation, and metabolic disorders were measured daily during 96 h following diagnosis of sepsis and once in controls. MMP-9/TIMP-1 ratios and disease severity scores were calculated. Use of vasopressors/inotropes, mechanical ventilation, and survival were recorded.

Results

Septic patients had lower MMP-9 and MMP-9/TIMP-1 ratios but higher TIMP-1 levels compared to controls. AUC-ROC for diagnosis of sepsis was 0.940 and 0.854 for TIMP-1 and 0.924 and 0.788 for MMP-9/TIMP-1 ratio (sepsis versus nonoperated and sepsis versus operated controls, resp.). Lower MMP-9 and MMP-9/TIMP-1 ratio and higher TIMP-1 levels were associated with shorter survival. MMP-9, TIMP-1, and MMP-9/TIMP-1 ratio correlated with biomarkers of inflammation, kidney and liver injury, coagulation, metabolic disorders, and disease severity scores. Use of vasopressors/inotropes was associated with higher TIMP-1 levels.

Conclusions

MMP-9, TIMP-1, and MMP-9/TIMP ratio were good diagnostic or prognostic biomarkers of sepsis after major abdominal surgery and were linked to sepsis-associated organ dysfunction.

The Novel HDAC8 Inhibitor WK2-16 Attenuates Lipopolysaccharide-Activated Matrix Metalloproteinase-9 Expression in Human Monocytic Cells and Improves Hypercytokinemia In Vivo

Dysregulated human monocytes/macrophages can synthesize and secrete matrix metalloproteinases (MMPs), which play important roles in the progression of sepsis. In this study, we investigated the effects and mechanism of a novel histone deacetylase (HDAC8) inhibitor, (E)-N-hydroxy-4-methoxy-2-(biphenyl-4-yl)cinnamide (WK2-16), on MMP-9 production and activation in stimulated human monocytic THP-1 cells. Our results demonstrated that the acetylation level of structural maintenance of chromosomes 3 (SMC3) was up-regulated by WK2-16 in THP-1 cells. Consistently, an in vitro enzyme study demonstrated that WK2-16 selectively inhibited HDAC8 activity. Moreover, the WK2-16 concentration dependently suppressed MMP-9-mediated gelatinolysis induced by tumor necrosis factor-α (TNF-α) or lipopolysaccharide (LPS). Additionally, WK2-16 significantly inhibited both MMP-9 protein and mRNA expression without cellular toxicity. Nevertheless, WK2-16 suppressed the extracellular levels of interleukin (IL)-6 from LPS-stimulated THP-1 cells. For the signaling studies, WK2-16 had no effect on LPS/TLR4 downstream signaling pathways, such as the NF-κB and ERK/JNK/P38 MAPK pathways. On the other hand, WK2-16 enhanced the recruitment of acetylated Yin Yang 1 (YY1) with HDAC1. Finally, in vivo studies indicated that WK2-16 could reduce the serum levels of TNF-α and IL-6 in endotoxemic mice. These results suggested that HDAC8 inhibition might provide a novel therapeutic strategy of hypercytokinemia in sepsis.