Microbial Translocation Markers Research Articles

Abstract 2441: Higher levels of LPS in blood plasma as potential novel biomarker for cancer risk in Puerto Rican people living with HIV

Abstract Background: People living with HIV (PWH) have a significantly higher risk of developing cancers than people without HIV (PWOH), even with suppressive antiretroviral therapy. Puerto Rico (PR) is considered a high-risk group disproportionately affected by HIV and a priority group for cancer prevention strategies. Dysbiosis of the human microbiota can contribute to persistent inflammation by upregulating TGF-β (microbial-induced oncogenesis biomarker), which can promote the translocation of microbial products into the bloodstream, increasing cancer risk at local and distant sites. However, the relationship between TGF-β, and microbial products such as lipopolysaccharide (LPS) and short-chain fatty acids (SCFA) in relation to HIV infection is poorly understood, therefore we aimed to quantify the levels of LPS and SCFA in the blood plasma of PWH vs. PWOH and investigated their relationship with cancer risk measured by TGF-β. Methods: Blood samples, sociodemographic, and clinical data from 80 adults (50 PWH and 30 PWOH) were collected. PWH were virally suppressed (<50 copies/mL) with a median CD4 count of 699.8 cells/µL. We measured TGF-β, LPS, and soluble CD14 (sCD14. marker of innate immune activation and microbial translocation) using immunoassays. SCFA (acetate, butyrate, and propionate) were measured using gas chromatography followed by mass spectrometry. Differences in the median levels of TGF-β, LPS, and SCFAs were evaluated using a Mann-Whitney test. We assessed the effects of LPS, SCFAs, and HIV infections in relationship with levels of TGF-β using multivariate fixed-effects regression analysis in R-statistical software. Results: PWH had significantly higher levels of TGF-β (4397 pg/mL vs. 1121 pg/mL, p=0.017), higher levels of LPS (38.97 pg/mL vs. 19.26 pg/mL, p<0.001), higher levels of sCD14 (1326 pg/mL vs. 1137 pg/mL, p=0.007), and significantly lower levels of butyrate (84.5 ng/mL vs. 62.0 ng/mL, p<0.001). Higher levels of TGF-b were associated with higher levels of LPS (rho=0.38, p=0.017) and higher levels of sCD14 (rho=0.27, p=0.016) these relationships remain significant after adjusting for HIV status (p<0.001). Conclusion: Our findings suggest that microbial products in blood plasma can contribute to higher cancer risk in Puerto Rican PWH and may represent potential novel biomarkers for cancer prevention. Citation Format: Jurelis Torres Reyes, Tanner L. Shull, Gabriel Borges-Velez, Veronica S. Sanchez Gonzalez, Jeannette L. Salgado Montilla, Josue Perez Santiago. Higher levels of LPS in blood plasma as potential novel biomarker for cancer risk in Puerto Rican people living with HIV [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2441.

Sex-specific differences in systemic immune responses in MIS-C children

Multisystem Inflammatory Syndrome in Children (MIS-C) is a rare manifestation of Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2) infection that can result in increased morbidity and mortality. Mounting evidence describes sex disparities in the clinical outcomes of coronavirus disease 2019 (COVID-19). However, there is a lack of information on sex-specific differences in immune responses in MIS-C. This study is an observational and cross-sectional study and we wanted to examine immune parameters such as cytokines, chemokines, acute phase proteins (APPs), growth factors, microbial translocation markers (MTMs), complement components and matrix metalloproteinases (MMPs) in MIS-C children, based on sex. Male children were associated with heightened levels of pro-inflammatory cytokines—IFNγ, IL-2, TNFα, IL-1α, IL-1β, IL-6, IL-12, G-CSF and GM-CSF, chemokines-CCL2, CCL11, CXCL1, CXCL8 and CXCL10, acute phase proteins-α-2M, CRP, growth factors VEGF and TGFα, microbial translocation markers- iFABP, LBP, EndoCAb, complement components—C1q, MBL and C3 and matrix metalloproteinases MMP-8 and MMP-9 compared to female children with MIS-C. These results indicate that the heightened immune response in males is a characteristic feature of MIS-C. These findings might explain the differential disease pathogenesis in males compared to females with MIS-C and facilitate a deeper understanding of this disease.

Distinct alterations of gut microbiota between viral- and non-viral-related hepatocellular carcinoma

Altered gut microbiota has been connected to hepatocellular carcinoma (HCC) occurrence and advancement. This study was conducted to identify a gut microbiota signature in differentiating between viral-related HCC (Viral-HCC) and non-hepatitis B-, non-hepatitis C-related HCC (NBNC-HCC). Fecal specimens were obtained from 16 healthy controls, 33 patients with viral-HCC (17 and 16 cases with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, respectively), and 18 patients with NBNC-HCC. Compositions of fecal microbiota were assessed by 16S rRNA sequencing. Bioinformatic analysis was performed by the DADA2 pipeline in the R program. Significantly different genera from the top 50 relative abundance were used to classify between subgroups of HCC by the Random Forest algorithm. Our data demonstrated that the HCC group had a significantly decreased alpha-diversity and changed microbial composition in comparison with healthy controls. Within the top 50 relative abundance, there were 11 genera including Faecalibacterium, Agathobacter, and Coprococcus that were significantly enhanced in Viral-HCC, while 5 genera such as Bacteroides, Streptococcus, Ruminococcus gnavus group, Parabacteroides, and Erysipelatoclostridium were enhanced in NBNC-HCC. Compared to Viral-HCC, the NBNC-HCC subgroup significantly reduced various short-chain fatty acid-producing bacteria, as well as declined fecal butyrate but elevated plasma surrogate markers of microbial translocation. Based on the machine learning algorithm, a high diagnostic accuracy to classify HCC subgroups was achieved with an area under the receiver-operating characteristic (ROC) curve (AUC) of 0.94. Collectively, these data revealed that gut dysbiosis was distinct according to etiological factors of HCC, which might play an essential role in hepatocarcinogenesis. These findings underscore the possible use of a gut microbiota signature for the diagnosis and therapeutic approaches regarding different subgroups of HCC.Key points• Gut dysbiosis is connected to hepatocarcinogenesis and can be used as a novel biomarker.• Gut microbiota composition is significantly altered in different etiological factors of HCC.• Microbiota-based signature can accurately distinguish between Viral-HCC and NBNC-HCC.

Primary HIV infection features colonic damage and neutrophil inflammation yet containment of microbial translocation.

Impairment of the gastrointestinal barrier leads to microbial translocation and peripheral immune activation, which are linked to disease progression. Data in the setting of primary HIV/SIV infection suggest that gut barrier damage is one of the first events of the pathogenic cascade, preceding mucosal immune dysfunction and microbial translocation. We assessed gut structure and immunity as well as microbial translocation in acutely and chronically-infected, combination antiretroviral therapy (cART)-naive individuals. Fifteen people with primary HIV infection (P-HIV) and 13 with chronic HIV infection (C-HIV) c-ART-naive participants were cross-sectionally studied. Gut biopsies were analysed in terms of gut reservoirs (total, integrated and unintegrated HIV DNA); tight junction proteins (E-cadherin, Zonula Occludens-1), CD4 + expression, neutrophil myeloperoxidase (histochemical staining); collagen deposition (Masson staining). Flow cytometry was used to assess γδ T-cell frequency (CD3 + panγδ+Vδ1+/Vδ2+). In plasma, we measured microbial translocation (LPS, sCD14, EndoCAb) and gut barrier function (I-FABP) markers (ELISA). P-HIV displayed significantly higher tissue HIV DNA, yet neutrophil infiltration and collagen deposition in the gut were similar in the two groups. In contrast, microbial translocation markers were significantly lower in P-HIV compared with C-HIV. A trend to higher mucosal E-cadherin, and gut γδ T-cells was also observed in P-HIV. Early HIV infection features higher HIV DNA in the gut, yet comparable mucosal alterations to those observed in chronic infection. In contrast, microbial translocation is contained in primary HIV infection, likely because of a partial preservation of E-cadherin and mucosal immune subsets, namely γδ T-cells.

Changes in surrogate markers of intestinal epithelial injury and microbial translocation in young and older men during prolonged occupational heat stress in temperate and hot conditions.

Exertional heat stress can cause damage to the intestinal epithelium and disrupt gastrointestinal barrier integrity, leading to microbial translocation (MT) linked to the development of heat stroke. This study aimed to assess age-related differences in markers of intestinal epithelial injury and MT following non-heat stress and high-heat stress exercise in healthy young and older men. Markers of intestinal epithelial injury (intestinal fatty acid-binding protein-'IFABP') and MT (soluble cluster of differentiation 14-'sCD14'; and lipopolysaccharide-binding protein-'LBP') were assessed in healthy young (18-30 y, n = 13) and older (50-70 y) men (n = 12). Blood samples were collected before, after 180min of moderate-intensity (metabolic rate: 200 W/m2) walking and following 60min recovery in either a non-heat stress [temperate: 21.9°C, 35% relative humidity (RH)] or high-heat stress (hot: 41.4°C, 35% RH) environment. There were no differences in IFABP and sCD14 between the young and older groups in the temperate condition, while LBP was greater in the older group (+ 0.66 ug/mL; + 0.08 to + 1.24 ug/mL). In the hot condition, the older group experienced greater increases in IFABP compared to the young group (+ 712pg/mL/hr; + 269 to + 1154pg/mL/hr). However, there were no clear between-group differences for sCD14 (+ 0.24 ug/mL/hr, - 0.22 to + 0.70 ug/mL/hr) or LBP (+ 0.86 ug/mL/hr, - 0.73 to + 2.46 ug/mL/hr). While older men may experience greater intestinal epithelial injury following exercise in the heat; this did not lead to a greater magnitude of microbial translocation relative to their younger counterparts.

Biomarkers of Growth Faltering and Neurodevelopmental Delay in Children who are HIV-Exposed but Uninfected: A Systematic Review.

Children who are HIV-exposed but uninfected (CHEU) are at risk of linear growth faltering and neurodevelopmental delay. Circulating biomarkers associated with these adverse outcomes may elucidate pathways of injury. To identify biomarkers associated with growth faltering and neurodevelopmental delay in CHEU. We performed a systematic review of electronic databases MEDLINE (1946-April 2021), EMBASE (1974-April 2021), Scopus (2004-April 2021), and PubMed (1985-April 2021), following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO, registration number CRD42021238363). We found seven studies associating biomarker abnormalities and growth outcomes in CHEUs and two studies on biomarker abnormalities and neurodevelopmental delay. Biomarker abnormalities associated with growth restriction were: C-reactive protein (CRP), tumour necrosis factor (TNF), interferon-gamma (IFN-γ), interleukin (IL)-12p70, IFN-γ-induced protein-10 (CXCL10/IP-10), lipopolysaccharide binding protein (LBP), insulin-like growth factor-1 (IGF-1), and IGF-binding protein-1 (IGFBP-1). Biomarkers associated with motor, language, and cognitive delay were CRP, IFN-γ, IL-1β, -2, -4, -6, -10, -12p70, neutrophil gelatinase-associated lipocalin (NGAL), granulocyte-macrophage colony-stimulating factor (GM-CSF), and matrix metalloproteinase- 9 (MMP-9). Elevated markers of inflammation (acute phase reactants, pro-inflammatory cytokines, chemokines) and intestinal microbial translocation are associated with growth faltering. Elevated markers of inflammation are associated with adverse neurodevelopment.

Fungal plasma biomarkers in patients admitted for inpatient treatment of alcohol use disorder.

Fungal plasma biomarkers have not been studied in patients with unhealthy alcohol use and no apparent end-stage liver disease. We examined the prevalence of fungal plasma biomarkers, assessed by the presence of anti-Saccharomyces cerevisiae antibodies (ASCA; IgA and IgM), and its disease correlates in patients with alcohol use disorder (AUD). We performed logistic regression analyses to detect the association between clinical and laboratory characteristics and the presence of fungal plasma biomarkers. We included 395 patients (75.9% male, median age of 49 years, and median body mass index of 25.6) who drank a median of 150 g of alcohol daily and had a median duration of AUD of 20 years. ASCA IgA and IgG were present in 34.4% and 14.9%, respectively, and 9.9% had both ASCA IgA and ASCA IgG. The presence of ASCA IgA was associated with male sex (p < 0.01); values of serum aspartate transferase (AST) (p = 0.02), gamma-glutamyl transferase (GGT) (p < 0.01), alkaline phosphatase (ALP) (p < 0.01), and bilirubin in the highest quartile (p < 0.01); Fibrosis-4 Index (FIB-4) values suggestive of advanced liver fibrosis (p < 0.01); and values of the macrophage activation factors sCD163 (p < 0.01) and sCD14 (p < 0.01), the cytokine IL-6 (p = 0.01), and lipopolysaccharide-binding protein in the highest quartile (p < 0.01). The presence of ASCA IgG was associated with omeprazole use (p = 0.04); values of AST (p = 0.04) and GGT (p = 0.04) in the highest quartile; FIB-4 values suggestive of advanced liver fibrosis (p < 0.01); and values of sCD163 (p < 0.01) in the highest quartile. The variables associated with the presence of both ASCA IgA and IgG were male sex (p = 0.04) and values of GGT (p = 0.04) and sCD163 in the highest quartile (p < 0.01). In AUD patients, the presence of fungal biomarkers in plasma was common and associated with FIB-4 values suggestive of advanced liver fibrosis and with markers of liver damage, monocyte activation, and microbial translocation, male gender, and omeprazole use. These findings suggest that the presence of plasma anti-Saccharomyces cerevisiae antibodies could be used as a biomarker for an elevated risk of progressive liver disease in patients with AUD.

#2511 ASSOCIATION OF CONSTIPATION, MICROBIAL TRANSLOCATION, AND INFLAMMATION IN HD PATIENTS

Abstract Background and Aims Increased gut permeability and intestinal dysbiosis may contribute to chronic inflammation, leading to accelerated atherosclerosis and cardiovascular complications in patients on haemodialysis (HD). Constipation is highly prevalent in HD patients and growing evidence suggested constipation can aggravate gut microbiota dysbiosis and gut inflammation. The aim of this study was to evaluate the association between markers of microbial translocation, intestinal permeability and inflammation in HD patients with and without constipation. Method A cross-sectional, observational study was conducted and 200 stable prevalent HD were enrolled. Serum zonulin, eotaxin-1, amyloid A, intestinal fatty acid-binding protein (iFABP), IL-6, endotoxin core antibodies (EndoCAb) and lipopolysaccharide binding protein (LBP) levels were measured. Functional constipation was defined according to the Rome IV criteria. Results Serum levels of zonulin and eotaxin-1 but not LPS, endo-Cab IgG, amyloid A and IL-6 were significantly higher in HD patients with constipation than in non-constipated HD controls. The multiple logistic regression analysis in constipated HD patients after adjustment for age, and BMI demonstrated that serum zonulin and eotaxin-1 were independently associated with constipation with an odds ratio (OR) of 1.24 (95% CI = 1.09-1.42, p = 0.0016) and 1.02 (95% CI = 1.01-1.03, p = 0.0001), respectively. Conclusion We demonstrate that there was association between serum eotaxin-1 and zonulin levels in constipated HD patients. This may indicates that increased intestinal inflammation or intestinal permeability in these patients but the significance of these findings need further investigation.

High-throughput proteomic analysis reveals systemic dysregulation in virally suppressed people living with HIV.

People living with HIV (PLHIV) on antiretroviral therapy (ART) exhibit persistent immune dysregulation and microbial dysbiosis, leading to the development of cardiovascular diseases (CVD). We initially compared plasma proteomic profiles between 205 PLHIV and 120 healthy controls (HCs) and validated the results in an independent cohort of 639 PLHIV and 99 HCs. Differentially expressed proteins (DEPs) were then associated to microbiome data. Finally, we assessed which proteins were linked with CVD development in PLHIV. Proximity extension assay technology was utilized to measure 1472 plasma proteins. Markers of systemic inflammation (CRP, D-Dimer, IL6, sCD14, and sCD163) and microbial translocation (IFABP) were measured by ELISA, and gut bacterial species were identified using shotgun metagenomic sequencing. Baseline CVD data were available for all PLHIV, and 205 PLHIV were recorded for the development of CVD during a 5-year follow-up. PLHIV on ART displayed systemic dysregulation of protein concentrations compared to HCs. Most of the DEPs originated from the intestine and lymphoid tissues, while they enriched in immune- and lipid metabolism-related pathways. Furthermore, we observed that DEPs originating from the intestine were associated with specific gut bacterial species. Finally, we identified upregulated proteins in PLHIV (GDF15, PLAUR, RELT, NEFL, COL6A3, and EDA2R), unlike most markers of systemic inflammation, associated with the presence and risk of developing CVD in 5-year follow-up. Our findings suggest a systemic dysregulation of protein concentrations in PLHIV, of which some proteins were associated with CVD development. Most of DEPs originated from the gut and were related to specific gut bacterial species. Cohorts included in this study are part of the Human Functional Genomics Project (HFGP) (www.humanfunctionalgenomics.org). The 2000HIV Human Functional Genomics Partnership Program is registered at ClinicalTrials.gov: (ID: NCT03994835). The 200HIV and 2000HIV studies are supported by the AIDS-fonds (#P-29001, Netherlands) and a ViiV healthcare grant (A18-1052), respectively; The ViiV healthcare grant was awarded to A.V., M.G.N., L.A.B.J., and Q.d.M; The Spinoza Prize (NWO SPI94-212) and ERC Advanced grant (no. 833247) were awarded to M.G.N; The Indonesia Endowment Fund for Education (LPDP) given by the Ministry of Finance of the Republic of Indonesia was awarded to N.V.

Increased Microbial Translocation is a Prognostic Biomarker of Different Immune Responses to ART in People Living with HIV.

Microbial translocation (MT) is a characteristic of human immunodeficiency virus (HIV) infection. Whether MT is also a biomarker of different immune responses to antiretroviral therapy (ART) received by people living with HIV (PLWH) is not known. We examined the presence of MT in a cohort of 33 HIV-infected immunological responders (IRs) and 28 immunological non-responders (INRs) (≥500 and <200 cluster of differentiation (CD)4+ T-cell counts/µL after 2 years of HIV-1 suppression, respectively) with no comorbidities. Plasma samples were used to measure the circulating levels of MT markers. All enrolled study participants had received 2 years of viral-suppression therapy. Levels of lipopolysaccharide (P = 0.0185), LPS-binding protein (P < 0.0001), soluble-CD14 (P < 0.0001), and endogenous endotoxin-core antibody (P < 0.0001) at baseline were significantly higher in INRs than in IRs and were associated with an increased risk of an immunological non-response, whereas the level of intestinal fatty acid-binding protein did not show this association. Analysis of receiver operating characteristic (ROC) curves demonstrated the utility of these individual microbial markers in discriminating INRs after ART in people living with HIV with high sensitivity, specificity, and area under the ROC curve. INRs in HIV infection are characterized by increased MT at baseline. These markers could be used as a rapid prognostic tool for predicting immune responses in people infected with the HIV.

Chemotherapy induced peripheral neuropathy (CIPN) and biomarkers of gut microbial translocation in long-term survivors of testicular germ cell tumors.

e17032 Background: Survivors of testicular germ cell tumors (GCT) may suffer from long-term treatment induced peripheral neuropathy. We hypothesized markers of gut microbial translocation after chemotherapy and/or radiotherapy may be contributing factors of peripheral neuropathy. Methods: GCT survivors (N = 194) from National Cancer Institute of Slovakia completed the EORTC QLQ Chemotherapy-Induced Peripheral Neuropathy (CIPN20) questionnaires during their annual follow-up visit at 10-year median (range 2-25). Biomarkers of gut microbial translocaion and dysbiosis (GMT) lipopolysaccharide (LPS), high mobility group box-1 (HMGB-1), d-lactate and sCD14 were measured from peripheral blood obtained during the same visit. Upon obtaining the scores from questionnaires per recommended guidelines, each score was correlated with biomarkers of GMT scored as as high or low (above and below median). Survivors were treated with orchiectomy only (N = 30), cisplatin-based chemotherapy (N = 135), radiotherapy to the retroperitoneum (N = 14) or both chemotherapy and radiotherapy (N = 10). Results: GCT survivors with higher vs lower plasma levels of HMGB-1 had worse overall CIPN20 score (median ± SD = 18 229.0 ± 13 644.2 vs 17 387.0 ± 5106.6 p = 0.048). Patients with higher vs lower plasma HMGB-1 also had worse motor function (9.0 ± 1.8 vs 8.0 ± 2.3, p = 0.036). Sensory and autonomy subscales of CIPN20 qestionaire did not show significant association with HMGB-1 (both P &gt; 0.05). There was no significant difference in CIPN20 symptom burden associated with LPS, d-lactate and sCD14 (all P &gt; 0.05). Conclusions: HMGB-1 may serve as a promising biomarker of CIPN20 in long-term cancer survivors. Proinflammatory pathways are suggested as underlying mechanism of CIPN. Furhter research and larger patient cohorts are needed to explore the pathogenesis of CIPN in GCT survivors.

Pyroptotic MAITs link microbial translocation with severity of alcohol-associated liver disease.

Mucosal-associated invariant T cells (MAITs) are markedly reduced in patients with alcohol-associated liver disease (ALD); however, the potential mechanism underlying MAITs' loss remains elusive. Hence, we aimed to explore what induced MAITs' loss and its clinical significance. The characteristics of pyroptotic MAITs were evaluated in a cohort of patients with ALD, including 41 patients with alcohol-associated liver cirrhosis (ALC) and 21 patients with ALC complicated with severe alcoholic hepatitis (ALC + SAH). In patients with ALD, blood MAITs were significantly decreased, hyperactivated, and displayed enhanced cell death through pyroptosis. The frequencies of pyroptotic MAITs increased with disease severity in patients with ALC and patients with ALC + SAH. These frequencies were negatively associated with the frequencies of MAITs and positively correlated with the levels of MAITs' activation, plasma levels of intestinal fatty acid-binding protein (a marker of intestinal enterocyte damage), soluble CD14, lipopolysaccharide-binding protein, and peptidoglycan recognition proteins (surrogate markers of microbial translocation). Pyroptotic MAITs were also found in the liver of patients with ALD. Interestingly, MAITs underwent further activation and pyroptosis in vitro under stimulation by Escherichia coli or direct bilirubin. Notably, blocking IL-18 signaling reduced the activation and frequencies of pyroptotic MAITs. The loss of MAITs in patients with ALD is, at least in part, due to cell death from pyroptosis and is associated with the severity of ALD. Such increased pyroptosis may be affected by dysregulated inflammatory responses to intestinal microbial translocation or direct bilirubin.

Translocation of bacterial LPS is associated with self-reported cognitive abilities in men living with HIV receiving antiretroviral therapy

BackgroundGut damage allows translocation of bacterial lipopolysaccharide (LPS) and fungal β-D-glucan (BDG) into the blood. This microbial translocation contributes to systemic inflammation and risk of non-AIDS comorbidities in people living with HIV, including those receiving antiretroviral therapy (ART). We assessed whether markers of gut damage and microbial translocation were associated with cognition in ART-treated PLWH.MethodsEighty ART-treated men living with HIV from the Positive Brain Health Now Canadian cohort were included. Brief cognitive ability measure (B-CAM) and 20-item patient deficit questionnaire (PDQ) were administered to all participants. Three groups were selected based on their B-CAM levels. We excluded participants who received proton pump inhibitors or antiacids in the past 3 months. Cannabis users were also excluded. Plasma levels of intestinal fatty acid binding protein (I-FABP), regenerating islet-derived protein 3 α (REG3α), and lipopolysaccharides (LPS = were quantified by ELISA, while 1–3-β-D-glucan BDG) levels were assessed using the Fungitell assay. Univariable, multivariable, and splines analyses were performed.ResultsPlasma levels of I-FABP, REG3α, LPS and BDG were not different between groups of low, intermediate and high B-CAM levels. However, LPS and REG3α levels were higher in participants with PDQ higher than the median.Multivariable analyses showed that LPS association with PDQ, but not B-CAM, was independent of age and level of education. I-FABP, REG3α, and BDG levels were not associated with B-CAM nor PDQ levels in multivariable analyses.ConclusionIn this well characterized cohort of ART-treated men living with HIV, bacterial but not fungal translocation was associated with presence of cognitive difficulties. These results need replication in larger samples.

Galectin-9 mediates gut-associated inflammation and disruption of tight junctions

Abstract Background: High levels of Galectin-9 (Gal-9), a β-galactoside-binding mammalian lectin, are associated with systemic inflammation in chronic viral infections like HIV, despite viral suppression by ART. Gut-systemic microbial translocation is a major contributor of persistent inflammation. Whether Gal-9 influences the integrity of the gut during viral infections remains unknown. Objective: Here we investigated the impact of Gal-9 in the interplay between gut-systemic microbial translocation in the setting of well-treated chronic HIV infection. Method: We assessed the levels of Gal-9 and sCD14 in the plasma of people with HIV on ART (PWH; n=25) and people without HIV (PWOH; n=15) by ELISA. The integrity of the gut epithelium in the presence and absence of rGal-9 was assessed in the HT-29 cell line by immunofluorescence. TNFa was used as a positive control to disrupt gut integrity. The levels of TNFa were measured by qPCR. Non parametric tests were used in the analysis. Results: Plasma Gal-9 and sCD14 were elevated in PWH compared to PWOH (all p&amp;lt;0.0001). Further, high Gal-9 levels correlated with high sCD14 in both the PWH (r=0.43, p=0.0317) and PWOH (r=0.79, p=0.0006) groups. Immunofluorescence revealed disruption of the Claudin tight junctions in vitroafter 24 hrs of rGal-9 treatment. rGal-9 also induced a 6-fold increase in the expression of TNFα in HT-29 cells. Conclusion: Our results show that Gal-9 is associated with markers of gut-systemic microbial translocation irrespective of HIV status and given the direct effects of rGal-9 on tight junction barrier function, targeting Gal-9 either by exploiting its secretory pathways or competitive blockade may serve as a novel therapeutic approach to control gut-associated inflammation.

Toll-like receptor 2 activation in monocytes contributes to systemic inflammation and alcohol-associated liver disease in humans.

In the context of gut leakiness and translocation of microbial products in alcohol-associated liver disease (ALD), it is possible that systemic and liver inflammation involve the activation of circulating monocyte through gut-derived factors. We explored the association between monocytes, microbial translocation, systemic inflammation, and ALD. Patients with alcohol use disorder following a rehabilitation program were compared with healthy controls. We determined the circulating number and proportion of monocyte subsets by FACS. The activation of signaling pathways by gut-derived microbes was analyzed by quantitative PCR in isolated monocytes. Cytokines secretion by monocytes and phagocytosis were assessed in vitro. Serum microbial translocation markers and cytokines were measured by ELISA and multiplex assay, respectively. ALD severity and liver inflammatory responses were analyzed in liver biopsies by various methods. In patients with alcohol use disorder, the number of blood monocytes increased compared with controls. Monocytes from patients with alcohol use disorder upregulated IL-1β and IL-8 together with toll-like receptor 2 and downstream AP-1, while fungal sensor CARD9 was downregulated. IL-1β and IL-8 were actively secreted upon stimulation in vitro with the toll-like receptor 2 ligand peptidoglycan. Exposure with Escherichia coli confirmed preserved bacterial phagocytic activity. In contrast, Candida albicans stimulation leads to downregulation of IL-1β and TNFα compared with controls. Systemic cytokines and monocyte changes correlated with microbial translocation. Hepatic IL-1β and IL-8 increased with ALD severity together with liver macrophage activation and upregulation of chemokines involved in monocyte attraction. Our results point to the contribution of activated monocytes to systemic inflammation and ALD. Monocytes likely infiltrate the liver, transform into monocyte-derived macrophages and release IL-1β and IL-8 in response to peptidoglycan and toll-like receptor 2 activation.

Circulating markers of microbial translocation and host response to bacteria with risk of colorectal cancer: a prospective, nested case-control study in men

Gut microbial dysbiosis contributes to colorectal cancer (CRC) pathogenesis, possibly mediated in part by increased intestinal permeability to endotoxin lipopolysaccharide (LPS), microbial translocation, and subsequent endotoxemia and inflammation. However, epidemiologic evidence linking circulating markers of microbial translocation with CRC risk is limited. We conducted a prospective, nested case-control study of 261 incident CRC cases and 261 controls (matched on age and time of blood draw) among 18,159 men with pre-diagnostic blood specimens in the Health Professionals Follow-Up Study (1993-2009). We examined three complementary markers of microbial translocation and host response to bacteria, including LPS-binding protein (LBP), soluble CD14 (sCD14), and endotoxincore antibody (EndoCAb) immunoglobulin M (IgM), with subsequent risk of CRC. Unconditional logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Pre-diagnostic circulating levels of sCD14 were associated with a higher risk of incident CRC. Compared to men in the lowest quartile, the multivariable OR was 1.90 (95% CI, 1.13-3.22) for men in the highest quartile (OR per standard deviation [SD] increase, 1.28; 95%CI 1.06-1.53; Ptrend=0.01). This positive association remained similar after adjusting for C-reactive protein, interleukin-6, and soluble tumor necrosis factor receptor-2, and within strata of putative CRC risk factors. We also observed a suggestive inverse association between EndoCAb IgM and risk of CRC (OR per SD increase, 0.84; 95%CI 0.69-1.02; Ptrend=0.09). Microbial translocation and host response to bacteria, as reflected by sCD14, is associated with risk of incident CRC in men. US National Institutes of Health.

The link between chronic cocaine use, B cell perturbations, and blunted immune recovery in HIV-infected individuals on suppressive ART.

We recently reveal that anti-CD4 autoantibodies contribute to blunted CD4+ T cell reconstitution in HIV+ individuals on antiretroviral therapy (ART). Cocaine use is common among HIV+ individuals and is associated with accelerated disease progression. However, the mechanisms underlying cocaine-induced immune perturbations remain obscure. We evaluated plasma levels of anti-CD4 IgG and markers of microbial translocation, as well as B-cell gene expression profiles and activation in HIV+ chronic cocaine users and non-users on suppressive ART, as well as uninfected controls. Plasma purified anti-CD4 IgGs were assessed for antibody-dependent cytotoxicity (ADCC). HIV+ cocaine users had increased plasma levels of anti-CD4 IgGs, lipopolysaccharide (LPS), and soluble CD14 (sCD14) versus non-users. An inverse correlation was observed in cocaine users, but not non-drug users. Anti-CD4 IgGs from HIV+ cocaine users mediated CD4+ T cell death through ADCC in vitro. B cells from HIV+ cocaine users exhibited activation signaling pathways and activation (cycling and TLR4 expression) related to microbial translocation versus non-users. This study improves our understanding of cocaine associated B cell perturbations and immune failure and the new appreciation for autoreactive B cells as novel therapeutic targets.

Altered gut microbiota is associated with different immunologic responses to antiretroviral therapy in HIV-infected men who have sex with men.

The association between gut microbiota and immunologic nonresponse among people living with HIV (PLHIV) on antiretroviral therapy (ART) is not well documented. This study aimed to characterize gut microbiota among HIV-infected men who have sex with men (MSM) with different immunologic responses. We recruited HIV-infected MSM and HIV-uninfected MSM (healthy controls, HC) in Guangzhou, June-October 2021. HIV-infected MSM were grouped into good immunological responders (GIR) (CD4 + T cell count ≥ 350 cells/μL) and poor immunological responders (PIR) (<350 cells/μL). Blood and stool samples were collected. Microbial translocation in serum was performed using enzyme-linked immunosorbent assay (ELISA). Bacterial 16S ribosomal DNA sequencing was performed on stool samples, and microbial metabolites were obtained through gas chromatography-mass spectrometry. 56 GIR, 41 PIR, and 51 HC were included. Microbial translocation marker soluble cluster of differentiation 14 (sCD14) in both GIR and PIR groups was significantly higher than that in HC. Compared with PIR or HC groups, the genera of Coprococcus, Blautia, Clostridium, and SMB53 were decreased, whereas Megamonas and Megasphaera were more abundant in GIR group. Compared with GIR or PIR groups, Bifidobacterium, Collinsella, Faecalibacterium, Oscillospira, and Roseburia were more abundant, whereas Escherichia was decreased in HC group. The levels of benzenoids, imidazoles, phenylpropanoic acids, phenylpropanoids, and pyridines showed strongly significant correlations between differential genera. This study presented a comprehensive landscape of gut microbiota in PLHIV with different treatment outcomes. Megamonas, Coprococcus and Blautia were the major genera correlated with different immunologic responses in PLHIV.

Correlation of marker periodontopathogenic bacteria with the immune component sCD14 secretion level in inflammatory periodontal diseases.

Lipopolysaccharide of the cell wall of gram-negative bacteria is a highly active biological substance: its interaction with toll-like receptors-4 (TLR-4) of myeloid cells leads to the activation of a cascade of inflammatory reactions, which is accompanied by the release of the soluble CD14 receptor (sCD14), which can be considered not only as a marker of cell activation by endotoxin, but also as a marker of microbial translocation. The aim of the work was to assess the prognostic significance of the sCD14 level in the samples of the periodontal pocket in inflammatory periodontal diseases and the relationship of its secretion with marker periodontopathogens. For the study, washes were obtained from the periodontal pocket (88 samples in total) from patients with chronic periodontitis and intact periodontium. The sCD14 content was determined by ELISA; during real-time PCR, the marker periodontopathogens Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, Porphyromonas gingivalis, Prevotella intermedia, and Candida albicans were isolated. The study revealed differences in the level of sCD14 secretion by groups: in chronic periodontitis, its content was 8,5 times higher than in the control group and amounted to 17,2±4,06 ng/ml (p=0,006). The frequency of detecting genes of periodontal pathogenic bacteria was 89,3% in patients with periodontitis and 31,25% in the group with intact periodontium. An interesting dependence of the detection of periodontal pathogenic bacteria in the group of patients with chronic periodontitis was established depending on the content of sCD14. Thus, at high concentrations of soluble coreceptor, a greater number of periodontopathogenic bacteria of the I and II orders were released. Thus, in inflammatory periodontal diseases, the processes of sCD14 synthesis change, which is probably due to the colonization of periodontal pathogenic bacteria and the action of their toxins and aggression factors. The relationship of marker periodontopathogens with the level of secretion of the immune component sCD14 and its effect on the structure of the periodontal index reflect shifts in the processes of reparative regeneration of the oral mucosa and the regulation of local immunity in response to microbial invasion.

Chitinase-3-like Protein 1 Is Associated with Poor Virologic Control and Immune Activation in Children Living with HIV.

Perinatally infected children living with HIV (CLWH) face lifelong infection and associated inflammatory injury. Chitinase-like 3 protein-1 (CHI3L1) is expressed by activated neutrophils and may be a clinically informative marker of systemic inflammation in CLWH. We conducted a multi-centre, cross-sectional study of CLWH, enrolled in the Early Pediatric Initiation Canadian Child Cure Cohort Study (EPIC4). Plasma levels of CHI3L1, pro-inflammatory cytokines, and markers of microbial translocation were measured by enzyme-linked immunosorbent assays. Longitudinal clinical characteristics (viral load, neutrophil count, CD4+ and CD8+ T-lymphocyte counts, and antiretroviral (ARV) regimen) were abstracted from patient medical records. One-hundred-and-five (105) CLWH (median age 13 years, 62% female) were included in the study. Seventy-seven (81%) had viral suppression on combination antiviral therapy (cART). The median CHI3L1 level was 25 μg/L (IQR 19-39). CHI3L1 was directly correlated with neutrophil count (ρ = 0.22, p = 0.023) and inversely correlated with CD4/CD8 lymphocyte ratio (ρ = -0.35, p = 0.00040). Children with detectable viral load had higher levels of CHI3L1 (40 μg/L (interquartile range, IQR 33-44) versus 24 μg/L (IQR 19-35), p = 0.0047). CHI3L1 levels were also correlated with markers of microbial translocation soluble CD14 (ρ = 0.26, p = 0.010) and lipopolysaccharide-binding protein (ρ = 0.23, p = 0.023). We did not detect differences in CHI3L1 between different cART regimens. High levels of neutrophil activation marker CHI3L1 are associated with poor virologic control, immune dysregulation, and microbial translocation in CLWH on cART.