Translocation Of Gut-derived Endotoxin Research Articles

Alleviation of Metabolic Endotoxemia by Milk Fat Globule Membrane: Rationale, Design, and Methods of a Double-Blind, Randomized, Controlled, Crossover Dietary Intervention in Adults with Metabolic Syndrome.

ABSTRACTBackgroundMilk fat globule membrane (MFGM) is a phospholipid-rich component of dairy fat that might explain the benefits of full-fat dairy products on cardiometabolic risk. Preclinical studies support that MFGM decreases gut permeability, which could attenuate gut-derived endotoxin translocation and consequent inflammatory responses that impair cardiometabolic health.ObjectivesTo describe the rationale, study design, and planned outcomes that will evaluate the efficacy of MFGM-enriched milk compared with a comparator beverage on health-promoting gut barrier functions in persons with metabolic syndrome (MetS).MethodsWe plan a double-blind, randomized, crossover trial in which people with MetS will receive a rigorously controlled eucaloric diet for 2 wk that contains 3 daily servings of an MFGM-enriched bovine milk beverage or a comparator beverage that is formulated with nonfat dairy powder, coconut and palm oils, and soy phospholipids. Compliance will be monitored by assessing urinary para-aminobenzoic acid that is added to all test beverages. After the intervention, participants will ingest a high-fat/high-carbohydrate meal challenge to assess metabolic excursions at 30-min intervals for 3 h. Nondigestible sugar probes also will be ingested prior to collecting 24-h urine to assess region-specific gut permeability. Intervention efficacy will be determined based on circulating endotoxin (primary outcome) and glycemia (secondary outcome). Tertiary outcomes include: gut and systemic inflammatory responses, microbiota composition and SCFAs, gut permeability, and circulating insulin and incretins.Expected resultsMFGM is expected to decrease circulating endotoxin and glycemia without altering body mass. These improvements are anticipated to be accompanied by decreased gut permeability, decreased intestinal and circulating biomarkers of inflammation, increased circulating incretins, and beneficial antimicrobial and prebiotic effects in the gut microbiome.ConclusionsDemonstration of improvements in gut barrier functions that limit endotoxemia and glycemia could help to establish direct evidence that full-fat dairy lowers cardiometabolic risk, especially in people with MetS.The clinical trial associated with this article has been registered at clinicaltrials.gov (NCT03860584).

Epigallocatechin gallate but not catechin prevents nonalcoholic steatohepatitis in mice similar to green tea extract while differentially affecting the gut microbiota

Catechin-rich green tea extract (GTE) protects against nonalcoholic steatohepatitis (NASH) by alleviating gut-derived endotoxin translocation and hepatic Toll-like receptor-4 (TLR4)–nuclear factor κB (NFκB) inflammation. We hypothesized that intact GTE would attenuate NASH-associated responses along the gut–liver axis to a greater extent than purified (−)-epigallocatechin gallate (EGCG) or (+)-catechin (CAT). Male C57BL/6J mice were fed a low-fat diet, a high-fat (HF) diet, or the HF diet with 2% GTE, 0.3% EGCG or 0.3% CAT for 8 weeks prior to assessing NASH relative to endotoxemia, hepatic and intestinal inflammation, intestinal tight junction proteins (TJPs) and gut microbial ecology. GTE prevented HF-induced obesity to a greater extent than EGCG and CAT, whereas GTE and EGCG more favorably attenuated insulin resistance. GTE, EGCG and CAT similarly attenuated serum alanine aminotransferase and serum endotoxin, but only GTE and EGCG fully alleviated HF-induced NASH. However, hepatic TLR4/NFκB inflammatory responses that were otherwise increased in HF mice were similarly attenuated by GTE, EGCG and CAT. Each treatment also similarly prevented the HF-induced loss in expression of intestinal TJPs and hypoxia inducible factor-1α and the otherwise increased levels of ileal and colonic TNFα mRNA and fecal calprotectin protein concentrations. Gut microbial diversity that was otherwise lowered in HF mice was maintained by GTE and CAT only. Further, microbial metabolic functions were more similar between GTE and CAT. Collectively, GTE catechins similarly protect against endotoxin–TLR4–NFκB inflammation in NASH, but EGCG and CAT exert differential prebiotic and antimicrobial activities suggesting that catechin-mediated shifts in microbiota composition are not entirely responsible for their benefits along the gut–liver axis.

Intestinal-level anti-inflammatory bioactivities of catechin-rich green tea: Rationale, design, and methods of a double-blind, randomized, placebo-controlled crossover trial in metabolic syndrome and healthy adults

Metabolic endotoxemia initiates low-grade chronic inflammation in metabolic syndrome (MetS) and provokes the progression towards more advanced cardiometabolic disorders. Our recent works in obese rodent models demonstrate that catechin-rich green tea extract (GTE) improves gut barrier integrity to alleviate the translocation of gut-derived endotoxin and its consequent pro-inflammatory responses mediated through Toll-like receptor-4/nuclear factor κB (TLR4/NFκB) signaling. The objective of this clinical trial is to establish the efficacy of GTE to alleviate metabolic endotoxemia-associated inflammation in persons with MetS by improving gut barrier function. We plan a double-blind, placebo-controlled cross-over trial in persons with MetS and age- and gender-matched healthy persons (18–65 y; n = 20/group) who will receive a low-energy GTE-rich (1 g/day; 890 mg total catechins) confection snack food while following a low-polyphenol diet for 28 days. Assessments will include measures of circulating endotoxin (primary outcome) and secondary outcomes including biomarkers of endotoxin exposure, region-specific measures of intestinal permeability, gut microbiota composition, diversity, and functions, intestinal and systemic inflammatory responses, and catechins and microbiota-derived catechin metabolites. Study outcomes will provide the first report of the GTE-mediated benefits that alleviate gut barrier dysfunction in relation to endotoxemia-associated inflammation in MetS persons. This is expected to help establish an effective dietary strategy to mitigate the growing burden of MetS that currently affects ~35% of Americans.

Green tea extract prevents obesity in male mice by alleviating gut dysbiosis in association with improved intestinal barrier function that limits endotoxin translocation and adipose inflammation

Gut-derived endotoxin translocation provokes obesity by inducing TLR4/NFκB inflammation. We hypothesized that catechin-rich green tea extract (GTE) would protect against obesity-associated TLR4/NFκB inflammation by alleviating gut dysbiosis and limiting endotoxin translocation. Male C57BL/6J mice were fed a low-fat (LF) or high-fat (HF) diet containing 0% or 2% GTE for 8 weeks. At Week 7, fluorescein isothiocyanate (FITC)-dextran was administered by oral gavage before assessing its serum concentrations as a gut permeability marker. HF-feeding increased (P<.05) adipose mass and adipose expression of genes involved in TLR4/NFκB-dependent inflammation and macrophage activation. GTE attenuated HF-induced obesity and pro-inflammatory gene expression. GTE in HF mice decreased serum FITC-dextran, and attenuated portal vein and circulating endotoxin concentrations. GTE in HF mice also prevented HF-induced decreases in the expression of intestinal tight junction proteins (TJPs) and hypoxia inducible factor-1α while preventing increases in TLR4/NFκB-dependent inflammatory genes. Gut microbial diversity was increased, and the Firmicutes:Bacteroidetes ratio was decreased, in HF mice fed GTE compared with HF controls. GTE in LF mice did not attenuate adiposity but decreased endotoxin and favorably altered several gut bacterial populations. Serum FITC-dextran was correlated with portal vein endotoxin (P<.001; rP=0.66) and inversely correlated with colonic mRNA levels of TJPs (P<.05; rP=−0.38 to −0.48). Colonic TJPs mRNA were inversely correlated with portal endotoxin (P<.05; rP=−0.33 to −0.39). These data suggest that GTE protects against diet-induced obesity consistent with a mechanism involving the gut-adipose axis that limits endotoxin translocation and consequent adipose TLR4/NFκB inflammation by improving gut barrier function.

Gut derived-endotoxin contributes to inflammation in severe ischemic acute kidney injury

BackgroundRecent researches indicate that the intestinal consequences of renal ischemia reperfusion (IR) would predispose to the translocation of gut-derived endotoxin. Here, we designed experiments to test the hypothesis that the gut-derived endotoxin has a potential role in mediating local inflammatory processes in the acutely injured kidney.MethodsRats were performed sham or renal IR surgery (60 min of bilateral renal ischemia, then 24 h of reperfusion) (n = 5). The intestinal structural and mucosa permeability were evaluated. Serum endotoxin and bacterial load in liver and mesenteric lymph nodes (MLN) were measured. Separate groups were pretreated with oral norfloxacin 20 mg/kg/day or saline for 4 weeks and divided into sham plus saline, sham plus norfloxacin, renal IR plus saline and renal IR plus norfloxacin group. Serum biochemistry and endotoxin were determined. Kidney pathological changes were scored. Protein or mRNA expression of toll-like receptor 4 (TLR4) and proinflammatory mediators were measured in kidney homogenate.ResultsRenal IR led to marked intestinal integrity disruption and increase in intestinal permeability. These are accompanied by low grade of endotoxemia as well as increased bacterial load in liver and MLN. The group pretreated with norfloxacin showed significant attenuation of the increase in serum urea, ALAT, ASAT and endotoxin. The increased renal protein or mRNA of TLR4 and proinflammatory mediators (IL-6 and MCP-1) in the unpretreated animals was significantly attenuated in the norfloxacin-pretreated animals. However, norfloxacin pretreatment did not produce any protective effects on renal tubular integrity.ConclusionsOur results show for the first time that gut-derived endotoxin, resulting from an increased intestinal permeability after severe renal IR, subsequently amplifies intrarenal inflammatory response by activation renal TLR4 signaling. Our study results do not establish that antibiotic administration was effective in improving the overall renal outcome. However, our findings may be the first step to understanding how to tailor therapies to mitigate intrarenal inflammation in select groups of patients.

Green tea extract protects against hepatic NFκB activation along the gut-liver axis in diet-induced obese mice with nonalcoholic steatohepatitis by reducing endotoxin and TLR4/MyD88 signaling

Green tea extract (GTE) reduces NFκB-mediated inflammation during nonalcoholic steatohepatitis (NASH). We hypothesized that its anti-inflammatory activities would be mediated in a Toll-like receptor 4 (TLR4)-dependent manner. Wild-type (WT) and loss-of-function TLR4-mutant (TLR4m) mice were fed a high-fat diet containing GTE at 0 or 2% for 8 weeks before assessing NASH, NFκB-mediated inflammation, TLR4 and its adaptor proteins MyD88 and TRIF, circulating endotoxin, and intestinal tight junction protein mRNA expression. TLR4m mice had lower (P<.05) body mass compared with WT mice but similar adiposity, whereas body mass and adiposity were lowered by GTE regardless of genotype. Liver steatosis, serum alanine aminotransferase, and hepatic lipid peroxidation were also lowered by GTE in WT mice, and were similarly lowered in TLR4m mice regardless of GTE. Phosphorylation of the NFκB p65 subunit and pro-inflammatory genes (TNFα, iNOS, MCP-1, MPO) were lowered by GTE in WT mice, and did not differ from the lowered levels in TLR4m mice regardless of GTE. TLR4m mice had lower TLR4 mRNA, which was also lowered by GTE in both genotypes. TRIF expression was unaffected by genotype and GTE, whereas MyD88 was lower in mice fed GTE regardless of genotype. Serum endotoxin was similarly lowered by GTE regardless of genotype. Tight junction protein mRNA levels were unaffected by genotype. However, GTE similarly increased claudin-1 mRNA in the duodenum and jejunum and mRNA levels of occludin and zonula occluden-1 in the jejunum and ileum. Thus, GTE protects against inflammation during NASH, likely by limiting gut-derived endotoxin translocation and TLR4/MyD88/NFκB activation.

Green Tea Extract Protects Against Hepatic NFκB Activation Along The Gut‐Liver Axis in Diet‐Induced Obese Mice With Nonalcoholic Steatohepatitis By Reducing Endotoxin and TLR4/MyD88 Signaling

Green tea extract (GTE) reduces NFκB‐mediated inflammation during nonalcoholic steatohepatitis (NASH). We hypothesized that its antiinflammatory activities would be mediated along the gut‐liver axis in a Toll‐like receptor‐4 (TLR4)‐dependent manner. Wild‐type (WT) and loss‐of‐function TLR4‐mutant (TLR4m) mice were fed a high‐fat diet containing 0 or 2% (w/w) GTE for 8 wk before assessing NASH, NFκB‐mediated inflammation, TLR4 adaptor proteins [myeloid differentiation 88 (MyD88) and TIR‐domain‐containing adapter‐inducing interferon‐β (TRIF)], circulating endotoxin, and intestinal tight junction proteins. In WT mice, phosphorylation of the NFκB p65 subunit and NFκB‐dependent gene expression (MCP‐1, iNOS, MPO) were lower in those provided GTE, and were not different from the lowered levels in TLR4m mice regardless of GTE. Compared with WT controls, TLR4m mice had lower TLR4 mRNA expression, and its expression was lowered by GTE in both genotypes. Protein expression of TRIF, which mediates MyD88‐independent TLR4 signaling, was unaffected by genotype and GTE. In contrast, MyD88 expression was lower in mice fed GTE regardless of genotype. Serum endotoxin was not exacerbated in TLR4m mice, but was lowered by GTE in both genotypes. Similarly, duodenal and jejunal claudin‐1 (CLDN‐1) mRNA expression were not affected in TLR4m mice, but GTE increased their expression in both genotypes. Serum endotoxin was inversely correlated with duodenal and jejunal CLDN‐1 (rp= −0.58 to −0.43, p&lt;0.05), and positively correlated with expression levels of TLR4 and phosphorylated‐p65 (rp= 0.46–0.57; p&lt;0.05). Thus, GTE protects against inflammation during NASH, likely by limiting gut‐derived endotoxin translocation and TLR4/MyD88‐dependent NFκB activation.Support or Funding InformationSupported by USDA‐NIFA.

Non-Alcoholic Steatohepatitis: Clinical and Translational Research.

The present review includes translational and clinical research that characterize non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Clinical and experimental evidence led to the recognition of the key toxic role played by lipotoxicity in the pathogenesis of NAFLD. The current understanding of lipotoxicity suggests that organ injury is initiated by the generation of oxidative metabolites and the translocation of gut-derived endotoxin. These processes lead to cellular injury and stimulation of the inflammatory responses mediated through a variety of molecules. The injury progresses through impairment of tissue regeneration and extracellular matrix turnover, leading to fibrogenesis and cirrhosis. Several cell types are involved in this process, predominantly stellate cells, macrophages and parenchymal cells. In response to inflammation, cytokines activate many signaling cascades that regulate fibrogenesis. This examination brings together research focusing on the underlying mechanisms of injury. It highlights the various processes and molecules that are likely involved in inflammation, immune modulation, and fibrogenesis in the liver. We searched electronic databases (Medline, Embase) for this review. This integrative work investigates different aspects of liver damage and possible repair. We aim to (1) determine the immuno-pathology of liver damage due to steatosis, (2) suggest diagnostic markers of NASH, (3) examine the role of behaviour in the development of NASH, and (4) develop common tools to study steatosis-induced effects in clinical studies. Special accent is put on co-morbidities with renal and neuropsychological disorders. Moreover, we review the evidence in literature on the role of moderate alcohol consumption in individuals that present NAFLD/NASH. behavior, diet, imaging, non-alcoholic fatty liver, nonalcoholic steatohepatitis, laboratory markers.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Alcohol, Signaling, and ECM Turnover

Alcohol is recognized as a direct hepatotoxin, but the precise molecular pathways that are important for the initiation and progression of alcohol-induced tissue injury are not completely understood. The current understanding of alcohol toxicity to organs suggests that alcohol initiates injury by generation of oxidative and nonoxidative ethanol metabolites and via translocation of gut-derived endotoxin. These processes lead to cellular injury and stimulation of the inflammatory responses mediated through a variety of molecules. With continuing alcohol abuse, the injury progresses through impairment of tissue regeneration and extracellular matrix (ECM) turnover, leading to fibrogenesis and cirrhosis. Several cell types are involved in this process, the predominant being stellate cells, macrophages, and parenchymal cells. In response to alcohol, growth factors and cytokines activate many signaling cascades that regulate fibrogenesis. This mini-review brings together research focusing on the underlying mechanisms of alcohol-mediated injury in a number of organs. It highlights the various processes and molecules that are likely involved in inflammation, immune modulation, susceptibility to infection, ECM turnover and fibrogenesis in the liver, pancreas, and lung triggered by alcohol abuse.

Effects of gut barrier dysfunction and NF‐κB activation on aggravating mechanism of severe acute pancreatitis

To study the effects of gut-derived endotoxin translocation and NF-kappaB activation on the aggravating mechanism of severe acute pancreatitis (SAP) and of treatment with pyrrolidine dithiocarbamate (PDTC) on rats with SAP. SD rats were randomly divided into sham operation group (SO), SAP group, SAP + lipopolysaccharide(LPS) group, pyrrolidine dithiocarbamate (PDTC) treatment group and LPS group. Biochemical parameters and cytokines were examined in the serum. Multiple organs pathological slices were examined. Expression of NF-kappaB mRNA in the liver tissue was detected by RT-PCR. Activation of NF-kappaB by the method of streptomycin avidin-peroxidase (SP) and expression of NF-kappaB p65 protein and its binding activity were analyzed by Western blot and electrophoretic mobidity shift assay (EMSA). Compared with sham operation group, the concentration of TNF-alpha, alanine aminotransferase (ALT), and diamine oxidase (DAO) in serum significantly increased in SAP + LPS group (P < 0.05). Pathological changes were markedly observed in tissues and the expression of NF-kappaB mRNA in the liver significantly increased (P < 0.05) also, the activation of NF-kappaB and binding activity of NF-kappaB p65 protein in the liver markedly increased (P < 0.01) in SAP + LPS group. Treatment with PDTC markedly reduced concentration of ALT, DAO and TNF-alpha, and the expression of NF-kappaB, and the pathologic scores, as well as significantly decreased the expression of NF-kappaB p65 protein. The activation and overexpression of NF-kappaB may participate in the aggravating mechanism of SAP. Treatment with PDTC has a protective effect on multiple organs damage in SAP.

Gut-derived endotoxin translocation is the main aggravating mechanism of acute severe pancreatitis

Severe acute pancreatitis (SAP) is a serious systemic disease. It exacerbates when complicated with multiple organ dysfunction syndrome or failure (MODS or MOF). However, the aggravating mechanism of SAP is still unknown up to now. Study showed that maintaining integrity of intestinal mucosal barrier function by given effective antibiotics, selective digestive decontamination (SDD) and enteral nutrition therapy to the patients with SAP could significantly reduce infection of pancreatic necrotic tissue and improve the patient's outcome. Combining the findings of gut-derived bacteria in animals' pancreas, liver, spleen, mesenteric lymph nodes with increasing concentration of inflammatory cytokines and endotoxin in plasma with SAP, we hypothesize that gut-derived endotoxin translocation is the main aggravating mechanism of SAP. The hypothesis holds potential as a target for therapeutic intervention.

Gut Mucosa in HIV Infection: “Immune Milk” Solution

In recent weeks, three noteworthy papers, published in PLoS Medicine, The Journal of Virology, and Nature Medicine, direct our attention to the gut as a critical target in HIV-1 infection and portal for therapeutic intervention. In PLoS Medicine, Mehandru and colleagues report that over half of the CD4+ T cells in the gut mucosa are lost within the first few weeks after HIV-1 infection and remain consistently low, compared to peripheral blood sources, despite long term antiretroviral therapy; furthermore, of the few CD4+ T cells that persist in the gut, a significant increase in immune activation is observed [1]. Consistent with earlier observation in SIV models, Veazey reminds us that the battle against HIV-1 should focus on the intestinal mucosa with therapeutic strategies to reduce gut immune activation [2]. The longitudinal study in The Journal of Virology by Guadalupe and colleagues showed a similar discordance in CD4+ T cells between restoration in peripheral blood and significant delay in the gut mucosa of chronic infected individuals during antiretroviral therapy. Here, the depletion in CD4+ T cells was associated with an increase in gut immune activation, CD8+ T cells, and associated inflammation with a corresponding decease in epithelial growth and repair-associated genes in gut mucosal tissue [3]. Brenchley and colleagues suggest in Nature Medicine that HIV infection causes this breakdown in the gut mucosa resulting in a “leaky gut,” thus allowing translocation of gut-derived endotoxin and the subsequent triggering of immune activation [4]. Collectively, these observations suggest that an orally active therapeutic, used in conjunction with antiretroviral therapy, be designed to both block gut-derived microbial translocation and stimulate restitution of the gut epithelium. The hope would be to restore immunological integrity of the intestinal mucosal barrier, thereby controlling immune activation, both locally, in the gut mucosa, and systemically by suppressing cellular targets distal to the gut that may directly contribute to the progression of AIDS [5–8]. The design for such an orally active therapeutic may be found in the complex formula of bovine colostrum and “immune milk,” which has long been recognized to offer passive protection from a broad number of enteric bacterial and viral pathogens, primarily via the transfer of immunoglobulins and suppression of gut-associated inflammation with promotion of mucosal repair and regeneration. The gut in chronic HIV-1-infected individuals appears to be reminiscent of newborn calves. Calves are born with a highly immature mucosal immune system and “leaky gut” which, if not immediately corrected, results in death due to infection and associated systemic immune activation. However, the cow's first milk rescues her calves from harmful gut microbes with a uniquely complex cocktail enriched with neutralizing polyclonal antibodies, cytokine tissue repair factors, and immune enhancing probiotics, such as Lactobacillus species. Regular consumption of biologically active bovine colostrum has been known for years to promote the development of infantile gut-associated lymphoid tissue and enhance CD4+ levels, while suppressing CD8+ and inflammatory bowl disease (IBD), including ulcerative colitis and Crohn disease [5]. The severity of IBD is often correlated with gut microbial-endotoxin translocation, which now appears in chronic HIV-1-infected individuals [4]. Similar to bovine colostrum, “immune milk” from properly vaccinated cows affords passive immunity against bacterial, viral, and fungal infections in the human gastrointestinal tract, as well as taming gut inflammation [8]. Hence, there may be lessons learned from Bessie's “immune milk.” If viewed as a unique formula that has evolved to complement gut immunity, “immune milk” may also provide relief in chronic HIV-infected individuals. Initial studies have already shown that ingestion of colostrum alleviates refractory diarrhea in HIV patients with a corresponding increase in both body weight and peripheral blood CD4+ T cells [9,10]. As we learn more about the gut microenvironment in HIV-infected individuals, Bessie may prove to be a worthwhile platform for the consideration of “immune milk” exhibiting both microbial endotoxin and HIV-neutralizing activity along with its innate anti-inflammatory and tissue repair and regenerative properties.

The mRNA expression patterns of tumor necrosis factor-alpha and TNFR-I in some vital organs after thermal injury.

To investigate changes of tumor necrosis factor-alpha (TNF-alpha) and TNFR-I expression in vital organs and their significance in the pathogenesis of multiple organ damage associated with endogenous endotoxin following major burns. Wistar rats subjected to a 35 % full-thickness scald injury were sacrificed at 12 h, 24 h, 48 h, and 72 h postburn, respectively. Meanwhile, eight rats were taken as normal controls. Tissue samples from liver, spleen, kidney, lung and intestine were collected to assay tissue endotoxin levels and measure TNF-alpha and TNFR-I expression. In addition, blood samples were obtained for the determination of organ function parameters. Endotoxin levels in liver, spleen and lung increased markedly after thermal injury, with the highest level in liver. The gene expression of TNF-alpha in liver, lung and kidney was up-regulated after thermal injury, while the TNFR-I mRNA expression in liver, lung, kidney and intestine was shown decreased throughout the observation period. Thus, the mRNA expression ratio of TNF-alpha to TNFR-I was significantly increased postburn, particularly in pulmonary tissue (67-fold). In addition, the significant correlations between the expression of TNFR-I or the expression ratio of TNF-alpha/TNFR mRNA in liver tissue and serum aspartate aminotransferase levels were noted (P<0.05-0.01). Similar results were also obtained between pulmonary TNF-alpha mRNA expression and myeloperoxidase activities (P<0.01), whereas there was a highly negative correlation between levels of renal TNFR-I mRNA expression and serum creatinine. Burn injury could result in the translocation of gut-derived endotoxin that was mainly distributed in the liver, spleen and lung. The translocated endotoxin then made the expression of TNF-alpha and TNFR-I mRNA up-regulated and down-regulated respectively in various organs, which might be involved in the pathogenesis of multiple organ damage following burns.

Free radicals, chemokines, and cell injury in HIV-1 and SIV infections and alcoholic hepatitis 2,3

Oxidative stress has been observed in HIV-1 infection and alcoholic liver disease. The formation of reactive oxygen species (ROS) contributes to cell injury through apoptosis and/or necrosis and secretion of proinflammatory cytokines and chemokines. The major sources of ROS and chemokines are the Kupffer cells. During chronic ethanol consumption they are primed and activated for enhanced formation of pro-inflammatory factors, probably as a result of ethanol-induced translocation of gut-derived endotoxin into the circulation. Pro-inflammatory factors produced in the liver stimulate neutrophilic and/or lymphocytic infiltration to this organ. The presence of inflammatory cells in the liver may compromise the hepatocytes to injury by releasing cytotoxic factors, i.e., ROS, cytolytic proteases. Kupffer cells also interact with the glycoprotein 120 of SIV and HIV-1, which can induce oxidative stress and chemokine release. CD4+ lymphocytes that are infected with the virus generate intracellular ROS, which in turn leads to apoptosis and cell death. Downregulation of CD4+ cells contributes to immunodeficiency, while enhanced sequestration of inflammatory cells in the liver during chronic ethanol use with or without HIV-1/SIV may result in hepatocyte injury and exacerbation of alcoholic liver disease.