Visceral adiposity in postmenopausal women is associated with a pro-inflammatory gut microbiome and immunogenic metabolic endotoxemia.

BACKGROUND: Obesity, and in particular abdominal obesity, is associated with an increased risk of developing a variety of chronic diseases. Obesity, aging, and menopause are each associated with differential shifts in the gut microbiome. Obesity causes chronic low-grade inflammation due to increased lipopolysaccharide (LPS) levels which is termed "metabolic endotoxemia." We examined the association of visceral adiposity tissue (VAT) area, circulating endotoxemia markers, and the gut bacterial microbiome in a cohort of aged postmenopausal women. METHODS: Fifty postmenopausal women (mean age 78.8 ± 5.3 years) who had existing adipose measurements via dual x-ray absorptiometry (DXA) were selected from the extremes of VAT: n = 25 with low VAT area (45.6 ± 12.5 cm2) and n = 25 with high VAT area (177.5 ± 31.3 cm2). Dietary intake used to estimate the Healthy Eating Index (HEI) score was assessed with a food frequency questionnaire. Plasma LPS, LPS-binding protein (LBP), anti-LPS antibodies, anti-flagellin antibodies, and anti-lipoteichoic acid (LTA) antibodies were measured by ELISA. Metagenomic sequencing was performed on fecal DNA. Female C57BL/6 mice consuming a high-fat or low-fat diet were treated with 0.4 mg/kg diet-derived fecal isolated LPS modeling metabolic endotoxemia, and metabolic outcomes were measured after 6 weeks. RESULTS: Women in the high VAT group showed increased Proteobacteria abundance and a lower Firmicutes/Bacteroidetes ratio. Plasma LBP concentration was positively associated with VAT area. Plasma anti-LPS, anti-LTA, and anti-flagellin IgA antibodies were significantly correlated with adiposity measurements. Women with high VAT showed significantly elevated LPS-expressing bacteria compared to low VAT women. Gut bacterial species that showed significant associations with both adiposity and inflammation (anti-LPS IgA and LBP) were Proteobacteria (Escherichia coli, Shigella spp., and Klebsiella spp.) and Veillonella atypica. Healthy eating index (HEI) scores negatively correlated with % body fat and anti-LPS IgA antibodies levels. Preclinical murine model showed that high-fat diet-fed mice administered a low-fat diet fecal-derived LPS displayed reduced body weight, decreased % body fat, and improved glucose tolerance test parameters when compared with saline-injected or high-fat diet fecal-derived LPS-treated groups consuming a high-fat diet. CONCLUSIONS: Increased VAT in postmenopausal women is associated with elevated gut Proteobacteria abundance and immunogenic metabolic endotoxemia markers. Low-fat diet-derived fecal-isolated LPS improved metabolic parameters in high-fat diet-fed mice giving mechanistic insights into potential pro-health signaling mediated by under-acylated LPS isoforms. Video Abstract.

Regulation of endotoxemia through the gut microbiota: The role of the Mediterranean diet and its components.

Endotoxemia is closely related to many diseases. As the largest endotoxin reservoir in the human body, the gut microbiota should be a key target for alleviating endotoxemia. The intestinal microbiota is believed to cause endotoxemia directly or indirectly by modifying the intestinal barrier function through dysbiosis, changing intestinal mucosal permeability and bacterial translocation. Diet is known to be the main environmental factor affecting the intestinal microbiota, and different diets and food components have a large impact on the gut microbiota. The Mediterranean diet, which received much attention in recent years, is believed to be able to regulate the gut microbiota, thereby maintaining the function of the intestinal barrier and alleviating endotoxemia. In this review, we focus on the relationship between the gut microbiota and endotoxemia, and how the Mediterranean dietary (MD) pattern can interfere with endotoxemia through the gut microbiota.

The anti-inflammatory effects of Fuzapladib in an endotoxemic porcine model.

Endotoxemia is a systemic inflammatory condition caused by lipopolysaccharide (LPS) stimulation, which produces inflammatory cytokines. Fuzapladib (FZP) inhibits the activation of adhesion molecules found on the surface of inflammatory cells, mitigating inflammation. In this study, we evaluated the therapeutic effects of fuzapladib on inflammatory cytokines and cardio-respiratory function using an LPS-induced endotoxemic porcine model. Fifteen pigs were separated into three groups: low-FZP (n=5), high-FZP (n=5), and control (n=5). Pigs were administered LPS under general anesthesia, and complete blood cell count, blood biochemistry, inflammatory cytokines, and cardio-respiratory function were evaluated. Statistical analysis was performed using a linear mixed-effects model and the Steel-Dwass test, with a significance threshold of P<0.05. During the 4 hr experimental period, one pig in the control group and two pigs in the low-FZP group died due to hypoxemia and hypotension. In the early acute changes following LPS administration, the high-FZP group maintained significantly higher arterial oxygen partial pressure and normal blood pressure compared to the control group. Although interleukin-6 levels increased in all groups during the experiment, they were significantly lower in the high-FZP group compared to the control group. Other parameters showed no clinically significant differences. In conclusion, while high-dose fuzapladib did not reduce organ damage in the porcine endotoxemia model, it suppressed interleukin-6 production, delayed the progression of deterioration, and contributed to a reduction in mortality during the observation period.

Dysbiosis and Regulation of Gut Microbiota in Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus is a serious metabolic disease having a high growth rate and becoming a global threat. An unhealthy lifestyle, food intake, and genetic susceptibility are the major factors responsible for this metabolic disorder. This disease results in hyperlipidemia, hyperglycemia, glucose intolerance, restricted insulin synthesis, and insulin resistance. Despite a variety of treatments currently available, cases of diabetes and resulting complications are on the rise. One promising approach to diabetes focuses on gut microflora and their associated metabolites. Gut microbiota has attracted widespread attention due to its crucial role in disease pathophysiology. This study explores the dysbiosis in the human gut microflora in Type 2 Diabetes Mellitus and how the gut microbiota influences metabolites related to T2DM. It also sheds light on early identification and targeted intervention for this. Understanding these mechanisms could potentially lead to more effective strategies for managing and preventing T2DM. The findings of our literature study are that gut microbiota can serve as biomarkers for early disease detection. Finally, we also highlight gut microecological therapeutic strategies focused on shaping the gut flora to emphasize the improvement of T2DM progression.

The Battle of LPS Clearance in Host Defense vs. Inflammatory Signaling.

Lipopolysaccharide (LPS) in blood circulation causes endotoxemia and is linked to various disease conditions. Current treatments focus on preventing LPS from interacting with its receptor Toll-like receptor 4 (TLR4) and reducing inflammation. However, our body has a natural defense mechanism: reticuloendothelial cells in the liver rapidly degrade and inactivate much of the circulating LPS within minutes. But this LPS clearance mechanism is not perfect. Excessive LPS that escape this clearance mechanism cause systemic inflammatory damage through TLR4. Despite its importance, the role of reticuloendothelial cells in LPS elimination is not well-studied, especially regarding the specific cells, receptors, and mechanisms involved. This gap hampers the development of effective therapies for endotoxemia and related diseases. This review consolidates the current understanding of LPS clearance, narrates known and explores potential mechanisms, and discusses the relationship between LPS clearance and LPS signaling. It also aims to highlight key insights that can guide the development of strategies to reduce circulating LPS by way of bolstering host defense mechanisms. Ultimately, we seek to provide a foundation for future research that could lead to innovative approaches for enhancing the body's natural ability to clear LPS and thereby lower the risk of endotoxin-related inflammatory diseases, including sepsis.

Time of day-dependent alterations of ferroptosis in LPS-induced myocardial injury via Bmal-1/AKT/ Nrf2 in rat and H9c2 cell.

Background: One of the most prevalent causes of death in sepsis is sepsis-induced cardiomyopathy (SICM). Circadian disruption is involved in the progress of sepsis. However, the molecular mechanism remains unclear. Methods: Here, we built LPS-induced SICM in-vivo and in-vitro models. LPS was administrated at the particular Zeitgeber times (ZT), ZT4-ZT10-ZT16-ZT22 and ZT10-ZT22 in vivo and vitro experiments, respectively. Results: In vivo experiment, injection of LPS at ZT10 induced higher infiltration of inflammatory cells and content of intracellular Fe2+, and lower level of Glutathione peroxidase 4 (GPX4) and cardiac function than other ZTs (P < 0.05), which indicated that myocardial ferroptosis in septic rat presented a time of day-dependent manner. Bmal-1 protein and mRNA levels of injection of LPS at ZT10 were lower than those at other three ZTs (P < 0.05). The ratios of pAKT/AKT at ZT4 and ZT10 LPS injection were lower than those at ZT16 and ZT22 (P < 0.05). Nrf2 protein levels at ZT10 LPS injection were lower than those at other three ZTs (P < 0.05). These results indicated that the circadian of Bmal-1 and its downstream AKT/Nrf2 pathway in rat heart were inhibited under SICM condition. Consistent with in-vivo experiment, we found LPS could significantly reduce the expressions of Bmal-1 protein and mRNA in H9c2 cell. Up-regulation of Bmal-1 could reduce the cell death, oxidative stress, ferroptosis and activation of AKT/Nrf2 pathway at both ZT10 and ZT22 LPS administration. Conversely, its down-regulation presented opposite effects. AKT siRNA could weaken the effect of Bmal-1 pcDNA. Conclusion: Ferroptosis presented the time of day-dependent manners via Bmal-1/AKT/Nrf2 in vivo and vitro models of SICM.

Gut Microbiota and Cytokine Profile in Cirrhosis.

Background and Aims: Gut dysbiosis and abnormal cytokine profiles are common in cirrhosis. This study aimed to evaluate the correlations between them. Methods: In the blood plasma of cirrhosis patients and controls, 27 cytokines were examined using a multiplex assay. The plasma levels of nitrites (stable metabolites of the endothelial dysfunction biomarker nitric oxide) and lipopolysaccharide (LPS) were examined. The fecal microbiota was assessed by 16S rRNA gene sequencing. Results: Levels of IL-1b, IL-2, IL-6, IL-13, IP-10, IFN-g, TNF-a, LPS, and nitrites were higher in cirrhosis patients than in controls, while levels of IL-4, IL-7, and PDGF-BB were lower. The LPS level was directly correlated with the levels of IL-1b, IL1-Ra, IL-9, IL-17, PDGF-BB, IL-6, TNF-a, and nitrites. The nitrite level was significantly directly correlated with the levels of TNF-a, GM-CSF, IL-17, and IL-12, and inversely correlated with the IL-7 level. TNF-a levels were directly correlated with ascites severity and the abundance of Negativicutes, Enterobacteriaceae, Veillonellaceae, and Klebsiella, while inversely correlated with the abundance of Firmicutes, Clostridia, and Subdoligranulum. IFN-g levels were directly correlated with the abundance of Bacteroidaceae, Lactobacillaceae, Bacteroides, and Megasphaera, and inversely correlated with the abundance of Verrucomicrobiota, Akkermansiaceae, Coriobacteriaceae, Akkermansia, Collinsella, and Gemella. IL-1b levels were directly correlated with the abundance of Comamonadaceae and Enterobacteriaceae and inversely correlated with the abundance of Marinifilaceae and Dialister. IL-6 levels were directly correlated with the abundance of Enterobacteriaceae, hepatic encephalopathy, and ascites severity, and inversely correlated with the abundance of Peptostreptococcaceae, Streptococcaceae, and Streptococcus. Conclusions: The abundance of harmful gut microbiota taxa and endotoxinemia directly correlates with the levels of proinflammatory cytokines.

Caspase-11 signaling promotes damage to hippocampal CA3 to enhance cognitive dysfunction in infection.

BACKGROUND: Cognitive dysfunction caused by infection frequently emerges as a complication in sepsis survivor patients. However, a comprehensive understanding of its pathogenesis remains elusive. METHODS: In our in vivo experiments, an animal model of endotoxemia was employed, utilizing the Novel Object Recognition Test and Morris Water Maze Test to assess cognitive function. Various techniques, including immunofluorescent staining, Western blotting, blood‒brain barrier permeability assessment, Limulus Amebocyte Lysate (LAL) assay, and Proximity-ligation assay, were employed to identify brain pathological injury and neuroinflammation. To discern the role of Caspase-11 (Casp11) in hematopoietic or non-hematopoietic cells in endotoxemia-induced cognitive decline, bone marrow chimeras were generated through bone marrow transplantation (BMT) using wild-type (WT) and Casp11-deficient mice. In vitro studies involved treating BV2 cells with E. coli-derived outer membrane vesicles to mimic in vivo conditions. RESULTS: Our findings indicate that the deficiency of Casp11-GSDMD signaling pathways reverses infection-induced cognitive dysfunction. Moreover, cognitive dysfunction can be ameliorated by blocking the IL-1 effect. Mechanistically, the absence of Casp11 signaling significantly mitigated blood‒brain barrier leakage, microglial activation, and synaptic damage in the hippocampal CA3 region, ultimately leading to improved cognitive function. CONCLUSION: This study unveils the crucial contribution of Casp11 and GSDMD to cognitive impairments and spatial memory loss in a murine sepsis model. Targeting Casp11 signaling emerges as a promising strategy for preventing or treating cognitive dysfunction in patients with severe infections.

Electroacupuncture pretreatment maintains mitochondrial quality control via HO-1/MIC60 signaling pathway to alleviate endotoxin-induced acute lung injury.

Electroacupuncture has been demonstrated to mitigate endotoxin-induced acute lung injury by enhancing mitochondrial function. This study investigates whether electroacupuncture confers lung protection through the regulation of mitochondrial quality control mediated by heme oxygenase-1 (HO-1) and the mitochondrial inner membrane protein MIC60. HO-1, an inducible stress protein, is crucial for maintaining mitochondrial homeostasis and protecting against lung injury. MIC60, a key component of the mitochondrial contact site and cristae organizing system, supports mitochondrial integrity. We employed genetic knockout/silencing and cell transfection techniques to model lipopolysaccharide (LPS)-induced lung injury, assessing changes in mitochondrial structure, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), and the expression of proteins essential for mitochondrial quality control. Our findings reveal that electroacupuncture alleviates endotoxin-induced acute lung injury and associated mitochondrial dysfunction, as evidenced by reductions in lung injury scores, decreased ROS production, and suppressed expression of proteins involved in mitochondrial fission and mitophagy. Additionally, electroacupuncture enhanced MMP and upregulated proteins that facilitate mitochondrial fusion and biogenesis. Importantly, the protective effects of electroacupuncture were reduced in models with Hmox1 knockout or Mic60 silencing, and in macrophages transfected with Hmox1-siRNA or Mic60-siRNA. Moreover, HO-1 was found to influence MIC60 expression during electroacupuncture preconditioning and LPS challenge, demonstrating that these proteins not only co-localize but also interact directly. In conclusion, electroacupuncture effectively modulates mitochondrial quality control through the HO-1/MIC60 signaling pathway, offering an adjunctive therapeutic strategy to ameliorate endotoxin-induced acute lung injury in both in vivo and in vitro settings.

Flavonoids in mitigating the adverse effects of canine endotoxemia.

In dogs, chronic enteropathies, and impaired gut integrity, as well as microbiome imbalances, are a major problem. These conditions may represent a continuous low endotoxin load, which may result in the development of diseases that are attributable to chronic inflammation. Flavonoids are polyphenolic plant compounds with numerous beneficial properties such as antioxidant, anti-inflammatory and antimicrobial effects. For our experiments, we isolated primary white blood cells (peripheral blood mononuclear cells and polymorphonuclear leukocytes) from healthy dogs and induced inflammation and oxidative stress with Escherichia coli and Salmonella enterica serovar Enteritidis lipopolysaccharide (LPS). In parallel, we treated the cell cultures with various flavonoids luteolin, quercetin and grape seed extract oligomeric proanthocyanidins (GSOP) alone and also in combination with LPS treatments. Then, changes in viability, reactive oxygen species (ROS) and tumor necrosis factor alpha (TNF-α) levels were measured in response to treatment with quercetin, luteolin and GSOP at 25 and 50 µg/mL concentrations. We found that ROS levels were significantly lower in groups which were treated by flavonoid and LPS at the same time compared to LPS-treated groups, whereas TNF-α levels were significantly reduced only by luteolin and quercetin treatment. In contrast, treatment with lower concentrations of GSOP caused an increase in TNF-α levels, while higher concentrations caused a significant decrease. These results suggest that the use of quercetin, luteolin and GSOP may be helpful in the management of chronic intestinal diseases in dogs with reduced intestinal barrier integrity or altered microbiome composition, or in the mitigation of chronic inflammatory processes maintained by endotoxemia. Further in vitro and in vivo studies are needed before clinical use.

PI3K/AKT and STAT3 pathways mediate the neuroprotective effect of dasatinib from acute cerebral injury in endotoxemic mice.

Background and purpose: Sepsis induces brain dysfunction and there is still a requirement for an unemployed viable restorative approach. This study aimed to investigate the role of dasatinib in the modulation of proinflammatory mediators, attenuating neuroinflammatory response, and it's signaling pathway during endotoxemia. Experimental approach: Twenty-four adult male Swiss-albino mice were randomized into four groups: sham (undergo laparotomy without cecal ligation and puncture, sepsis (laparotomy with cecal ligation and puncture), vehicle-dimethyl sulfoxide, dasatinib (20 mg/kg/day) intraperitoneally. Brain tissue used for assessment of interleukin (IL)-6, IL-1ß, tumor necrosis factor-alpha (TNF-α), IL-10, Toll-like receptor 4 (TLR4), protein kinase B (AKT), phosphoinositide 3-kinases (PI3K), signal transducer and activator of transcription 3 (STAT3), and histopathological examination. Findings/Results: Brain tissue levels of TNF-α, IL-6, and IL1 ß were higher in the sepsis group than in the sham and vehicle groups. The dasatinib group had considerably lower tissue levels of these markers and significantly higher tissue values of IL-10 than the sepsis and vehicle groups. The sham group had much lower tissue values of TLR4, AKT, STAT3, and PI3k than in sepsis and vehicle groups. Furthermore, tissue levels of these markers in the dasatinib group were considerably lower than those in the sepsis and vehicle groups. Histopathology demonstrated that dasatinib might considerably reduce brain damage and the intensity of neuroinflammation when compared to sepsis and vehicle groups that showed extensive brain inflammation and damage. Conclusion and implication: Dasatinib attenuated endotoxemia-induced acute brain damage in mice via modulating effects on TLR4, PI3K, AKT, and STAT3 downstream signaling pathways.

The natural sesquiterpene lactone inulicin suppresses the production of pro-inflammatory mediators via inhibiting NF-κB and AP-1 pathways in LPS-activated macrophages.

OBJECTIVE: Inulicin is a sesquiterpene lactone in Inulae Flos which is clinically used for the treatment of inflammatory diseases, such as cough, sputum production, and vomiting. This study aimed to demonstrate the anti-inflammatory activity and the underlying mechanism of inulicin by using lipopolysaccharide (LPS)-induced in vitro and in vivo models. METHODS: LPS-stimulated RAW264.7 macrophages and mouse peritoneal macrophages (MPMs) were used for evaluating the in vitro anti-inflammatory activity of inulicin, while endotoxemia mice were used for evaluating its in vivo action. Cytokines' levels were determined by ELISA. RT-qPCR and western blot were used for assaying the mRNA and protein levels of target genes. RAW264.7 macrophages transfected with reporter plasmid pNFκB-TA-luc or pAP1-TA-luc were used for assaying the activation of NF-κB or AP-1 signaling. RESULTS: Inulicin significantly inhibited LPS-induced production of NO, IL-6, c-c motif chemokine ligand 2 (CCL2), and IL-1ß in both RAW264.7 cells and MPMs. Mechanism study indicated that it could suppress inducible nitric oxide synthase, IL-6, CCL2, and IL-1ß mRNA levels in LPS-stimulated RAW264.7 cells. Moreover, inulicin inhibited IκBα phosphorylation and prevented the nuclear translocation of p65, thereby inactivating NF-κB signaling. Concurrently, it also inhibited AP-1 signaling by reducing the phosphorylation of C-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK). In endotoxemia mice, a single intraperitoneal administration of inulicin could decrease the production of pro-inflammatory cytokines in serum and peritoneal lavage fluid. CONCLUSIONS: The present study demonstrates that inulicin possesses anti-inflammatory effects in vitro and in vivo, which suggests that inulicin might be a promising candidate for the treatment of inflammatory diseases.

Gestationally administered RAS modulators reprogram endotoxic cardiovascular and inflammatory profiles in adult male offspring of preeclamptic rats.

Previous studies showed that preeclampsia (PE) amplifies cardiovascular dysfunction induced by endotoxemia in adult male, but not female, offspring. Here, we asked if such aggravated endotoxic insult could be nullified by modulators of the renin-angiotensin system (RAS). PE was induced by gestational administration of Nω-nitro-L-arginine methyl ester(L-NAME, a nitric oxide synthase inhibitor). Adult male offspring of PE mothers treated gestationally with angiotensin 1-7 (Ang1-7, angiotensin II-derived vasodilator), losartan (AT1 receptor antagonist), pioglitazone (peroxisome proliferator-activated receptor gamma, PPARγ, agonist), or combined losartan/pioglitazone were instrumented with femoral indwelling catheters and challenged intravenously with a 5-mg/kg dose of lipopolysaccharides (LPS, 5 mg/kg). LPS caused significant decreases in blood pressure (BP) and spectral index of overall heart rate variability and increases in heart rate and left ventricular contractility (dP/dtmax). These effects were mostly reduced to similar magnitudes by individual drug therapies. In offspring born to Ang1-7-treated dams, the spectral index of cardiac sympathovagal balance showed elevated sympathetic dominance in response to LPS. Immunohistochemistry revealed that Ang1-7, but not losartan/pioglitazone, abolished the exaggerated increases in toll-like receptor 4 (TLR-4) expression caused by PE/LPS in heart tissues and neuronal circuits of brainstem rostral ventrolateral medulla (RVLM). By contrast, the losartan/pioglitazone regimen, but not Ang1-7, decreased and increased angiotensin converting enzyme (ACE) and ACE2 expression, respectively. Together, gestational fetal reprogramming of Ang II (depression) and Ang1-7 (activation) arms of RAS effectively counterbalance worsened endotoxic cardiovascular and inflammatory profiles in adult male offspring of PE rats.

Metabolic Endotoxemia: From the Gut to Neurodegeneration.

Metabolic endotoxemia is a severe health problem for residents in developed countries who follow a Western diet, disrupting intestinal microbiota and the whole organism's homeostasis. Although the effect of endotoxin on the human immune system is well known, its long-term impact on the human body, lasting many months or even years, is unknown. This is due to the difficulty of conducting in vitro and in vivo studies on the prolonged effect of endotoxin on the central nervous system. In this article, based on the available literature, we traced the path of endotoxin from the intestines to the blood through the intestinal epithelium and factors promoting the development of metabolic endotoxemia. The presence of endotoxin in the bloodstream and the inflammation it induces may contribute to lowering the blood-brain barrier, potentially allowing its penetration into the central nervous system; although, the theory is still controversial. Microglia, guarding the central nervous system, are the first line of defense and respond to endotoxin with activation, which may contribute to the development of neurodegenerative diseases. We traced the pro-inflammatory role of endotoxin in neurodegenerative diseases and its impact on the epigenetic regulation of microglial phenotypes.

Risk factors and prognostic value of endotoxemia in patients with acute myocardial infarction.

Background: There is increasing evidence regarding the association between endotoxemia and the pathogenesis of atherosclerosis and myocardial infarction (MI). During the acute phase of MI, endotoxemia might increase inflammation and drive adverse cardiovascular (CV) outcomes. We aimed to explore the risk factors and prognostic value of endotoxemia in patients admitted for acute MI. Methods: Patients admitted to the coronary care unit of Dijon University Hospital for type 1 acute MI between 2013 and 2015 were included. Endotoxemia, assessed by plasma lipopolysaccharide (LPS) concentration, was measured by mass spectrometry. Major adverse CV events were recorded in the year following hospital admission. Results: Data from 245 consecutive MI patients were analyzed. LPS concentration at admission markedly increased with age and diabetes. High LPS concentration was correlated with metabolic biomarkers (glycemia, triglyceride, and total cholesterol) but not with CV (troponin Ic peak and N-terminal pro-brain natriuretic peptide) or inflammatory biomarkers (C-reactive protein, IL6, IL8, and TNFα). LPS concentration was not associated with in-hospital or 1-year outcomes. Conclusions: In patients admitted for MI, higher levels of endotoxins were related to pre-existing conditions rather than acute clinical severity. Therefore, endotoxins measured on the day of MI could reflect metabolic chronic endotoxemia rather than MI-related acute gut translocation.

Gut barrier dysfunction, endotoxemia and inflammatory response in STEMI patients and effect of primary PCI.

BACKGROUND: Gut-derived bacterial and endotoxin translocation induce systemic inflammation, which exerts a pivotal pathogenetic role in all phases of atherosclerosis. OBJECTIVES: To investigate prospectively the gut barrier function, endotoxin translocation and inflammatory response in ST-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary artery intervention (PPCI). METHODS: Twenty-seven patients with STEMI that underwent successful PPCI were subjected to peripheral blood sampling at 3-time points; before PPCI (day0), 24 h (day1) and 96 h (day4) after PPCI and were compared with 20 chronic coronary syndrome (CCS) patients and 11 healthy controls. Serum ZO-1, I-FABP and endotoxin concentrations were determined by ELISA. Concentrations of cytokines IL-1ß, -6, -8, -10 and TNF-α were determined by flow cytometry. RESULTS: Patients with STEMI before PPCI (day0) had increased serum ZO-1 and endotoxin, both at significantly higher levels compared to CCS patients. STEMI induced also significant increases of the cytokines IL-6, -8 and -10. After PPCI, a significant improvement of gut barrier integrity (ZO-1) and endotoxemia was observed from the first day. At day4 post PPCI, systemic endotoxin and cytokines IL-6, -8 and -10 levels were reduced to control levels. Serum ZO-1 levels were positively correlated with systemic IL-10 concentrations (r = 0.471). CONCLUSION: STEMI is associated with gut barrier dysfunction, systemic endotoxemia and inflammatory response, which improve rapidly following successful PPCI.

Dietary Anthocyanins Mitigate High-Fat Diet-Induced Hippocampal Inflammation in Mice.

BACKGROUND: Obesity and consumption of high-fat diets (HFD) are associated with intestinal permeabilization and increased paracellular transport of endotoxins, which can promote neuroinflammation. Inflammation can affect the hypothalamic pituitary adrenal (HPA) axis, which controls responses to stress and downregulates the brain-derived neurotrophic factor (BDNF), which can promote anxiety and depression, conditions frequently found in obesity. We previously showed that consumption of anthocyanins (AC) mitigate HFD-induced insulin resistance, intestinal permeability, and inflammation. OBJECTIVES: This study investigated if a dietary supplementation with a cyanidin- and delphinidin-rich extract (CDRE) could counteract HFD/obesity-induced hippocampal inflammation in mice. METHODS: C57BL/6J male mice were fed for 14 wk on one of the following diets: 1) a control diet containing 10% total calories from fat (C), 2) a control diet supplemented with 40 mg AC/kg body weight (BW) (CAC), 3) a HFD containing 60% total calories from fat (lard) (HF), or 4) the HFD supplemented with 2, 20, or 40 mg AC/kg BW (HFA2, HFA20, and HFA40, respectively). In plasma and in the hippocampus, parameters of neuroinflammation and the underlying cause (endotoxemia) and consequences (alterations to the HPA and BDNF downregulation) were measured. RESULTS: Consumption of the HFD caused endotoxemia. Accordingly, hippocampal Tlr4 mRNA levels were 110% higher in the HF group, which were both prevented by CDRE supplementation. Consumption of the HFD also caused: 1) microgliosis and increased expression of genes involved in neuroinflammation, that is, Iba-1, Nox4, Tnfα, and Il-1ß, 2) alterations of HPA axis regulation, that is, with low expression of mineralocorticoid (MR) and glucocorticoid (GR) receptors; and 3) decreased Bdnf expression. Supplementation of HFD-fed mice with CDRE mitigated neuroinflammation, microgliosis, and MR and BDNF decreases. CONCLUSIONS: CDRE supplementation mitigates the negative effects associated with HFD consumption and obesity in mouse hippocampus, in part by decreasing inflammation, improving glucocorticoid metabolism, and upregulating BDNF.

Links Between Adipose Tissue Gene Expression of Gut Leakage Markers, Circulating Levels, Anthropometrics, and Diet in Patients with Coronary Artery Disease.

Background: Recent studies suggest gut-derived lipopolysaccharide (LPS)-translocation to play a role in both systemic inflammation and in inflammatory adipose tissue. We aimed to investigate whether circulating LPS-related inflammatory markers and corresponding genetic expression in adipose tissue were associated with obesity, cardiometabolic risk factors, and dietary habits in patients with coronary artery disease. Methods: Patients (n=382) suffering a myocardial infarction 2-8 weeks prior to inclusion were enrolled in this cross-sectional study. Subcutaneous adipose tissue (SAT), taken from the gluteal region, and fasting blood samples were collected at inclusion for determination of genetic expression of LPS-binding protein (LBP), CD14, toll-like receptor 2 (TLR2), and TLR4 in SAT, and LPS, LBP, and soluble cluster of differentiation 14 (sCD14) in the circulation. All patients filled out a dietary registration form. Results: Patients (median age 74 years, 25% women), had a median body mass index (BMI) of 25.9 kg/m2. Circulating levels of LBP correlated to BMI (p=0.02), were significantly higher in overweight or obese (BMI≥25 kg/m2) compared to normal- or underweight patients (BMI<25 kg/m2), and were significantly elevated in patients with T2DM, hypertension, and MetS, compared to patients without (p≤0.04, all). In SAT, gene expression of CD14 and LBP correlated significantly to BMI (p≤0.001, both), and CD14 and TLR2 expressions were significantly higher in patients with T2DM and MetS compared to patients without (p≤0.001, both). Circulating and genetically expressed CD14 associated with use of n-3 PUFAs (p=0.008 and p=0.003, respectively). No other significant associations were found between the measured markers and dietary habits. Conclusion: In patients with established CAD, circulating levels of LBP and gene expression of CD14 and TLR2 in SAT were related to obesity, MetS, T2DM, and hypertension. This suggests that the LPS-LBP-CD14 inflammatory axis is activated in the chronic low-grade inflammation associated with cardiometabolic abnormalities, whereas no significant associations with dietary habits were observed.

Inhibiting the CB1 receptor in CIH-induced animal model alleviates colon injury.

Obstructive sleep apnea (OSA) can lead to intestinal injury, endotoxemia, and disturbance of intestinal flora. Additionally, as a crucial component of the endocannabinoid system, some studies have demonstrated that cannabinoid 1 (CB1) receptors are closely linked to the multiple organ dysfunction triggered by OSA. However, the role of the CB1 receptor in alleviating OSA-induced colon injury remains unclear. Here, through the construction of the OSA classic model, we found that the colon tissue of chronic intermittent hypoxia (CIH)-induced mice exhibited an overexpression of the CB1 receptor. The results of hematoxylin-eosin staining and transmission electron microscopy revealed that inhibition of the CB1 receptor could decrease the gap between the mucosa and muscularis mucosae, alleviate mitochondrial swelling, reduce microvilli shedding, and promote the recovery of tight junctions of CIH-induced mice. Furthermore, CB1 receptor inhibition reduced the levels of metabolic endotoxemia and inflammatory responses, exhibiting significant protective effects on the colon injury caused by CIH. At the molecular level, through western blotting and real-time polymerase chain reaction techniques, we found that inhibiting the CB1 receptor can significantly increase the expression of ZO-1 and Occludin proteins, which are closely related to the maintenance of intestinal mucosal barrier function. Through 16S rRNA high-throughput sequencing and short-chain fatty acid (SCFA) determination, we found that inhibition of the CB1 receptor increased the diversity of the microbial flora and controlled the makeup of intestinal flora. Moreover, butyric acid concentration and the amount of SCFA-producing bacteria, such as Ruminococcaceae and Lachnospiraceae, were both markedly elevated by CB1 receptor inhibition. The results of the spearman correlation study indicated that Lachnospiraceae showed a positive association with both ZO-1 and Occludin but was negatively correlated with the colon CB1 receptor, IL-1ß, and TNF-α. According to this study, we found that inhibiting CB1 receptor can improve CIH-induced colon injury by regulating gut microbiota, reducing mucosal damage and promoting tight junction recovery. KEY POINTS: •CIH leads to overexpression of CB1 receptor in colon tissue. •CIH causes intestinal flora disorder, intestinal mucosal damage, and disruption of tight junctions. •Inhibition of CB1 receptor can alleviate the colon injury caused by CIH through regulating the gut microbiota, reducing mucosal injury, and promoting tight junction recovery.

Association of Circulating Markers of Microbial Translocation and Hepatic Inflammation with Liver Injury in Patients with Type 2 Diabetes.

BACKGROUND: Virtually the entire spectrum of liver disease is observed in association with type 2 diabetes mellitus (T2DM); indeed, T2DM is now the most common cause of liver disease in the U.S. We conducted a pilot study to investigate the relevance of increased microbial translocation and systemic inflammation in the development of liver injury in patients with T2DM. METHODS: Patients with T2DM (n = 17) and non-diabetic controls (NDC; n = 11) aged 25-80 yrs. participated in this study. Serum levels of endotoxin, calprotectin, soluble CD14 and CD163, and several inflammatory cytokines were measured. In addition to standard liver injury markers, ALT and AST, novel serum markers of liver injury, keratin 18 (K-18) M30 (apoptosis-associated caspase-cleaved keratin 18), and M65 (soluble keratin 18) were evaluated. Statistical analyses were performed using the Mann-Whitney test to assess differences between study groups. Pearson's correlation analysis was performed to determine the strength of association between two variables using GraphPad Prism 9.5.0 software. RESULTS: Patients with T2DM had significantly higher levels of sCD14 in comparison to NDC, suggesting an increase in gut permeability, microbial translocation, and monocyte/macrophage activation. Importantly, relevant to the ensuing inflammatory responses, the increase in sCD14 in patients with T2DM was accompanied by a significant increase in sCD163, a marker of hepatic Kupffer cell activation and inflammation. Further, a positive correlation was observed between sCD163 and endotoxin and sCD14 in T2DM patients but not in NDC. In association with these changes, keratin 18 (K-18)-based serum markers (M65 and M30) that reflect hepatocyte death were significantly higher in the T2DM group indicating ongoing liver injury. Notably, both M65 and M30 levels correlated with sCD14 and sCD163, suggesting that immune cell activation and hepatic inflammation may be linked to the development of liver injury in T2DM. CONCLUSIONS: These findings suggest that the pathogenic changes in the gut-liver axis, marked by increased microbial translocation, may be a major component in the etiology of hepatocyte inflammation and injury in patients with T2DM. However, larger longitudinal studies, including histological evidence, are needed to confirm these observations.