Alcohol Use Is Associated With Intestinal Dysbiosis and Dysfunctional CD8+ T-Cell Phenotypes in Persons With Human Immunodeficiency Virus.

BACKGROUND: Inflammation persists among persons with human immunodeficiency virus (PWH) despite effective antiretroviral therapy and may contribute to T-cell dysfunction. Alcohol use is prevalent among PWH and promotes intestinal leak, dysbiosis, and a proinflammatory milieu. Whether alcohol use is associated with T-cell late differentiation remains to be investigated. METHODS: Data and samples from PWH (N = 359 of 365) enrolled in the New Orleans Alcohol Use in HIV Study were used. Alcohol use was assessed by self-report (Alcohol Use Disorders Identification Test; lifetime alcohol exposure; 30-day Alcohol Timeline Followback) and phosphatidylethanol (PEth) quantitation. In a subset of participants, fecal bacterial content was assessed by ribosomal 16S marker gene deep sequencing and quantitative polymerase chain reaction. Intestinal leak was assessed by fecal-to-plasma α-1-antitrypsin (A1AT) enzyme-linked immunosorbent assay ratio. Peripheral T-cell populations were quantified by flow cytometry. RESULTS: Alcohol Use Disorder Identification Test scores were positively associated with activated-senescent, exhausted, and terminal effector memory CD45RA+CD8+ but not CD4+ T cells (cells/µL) after confounder adjustment (P < .050). Phosphatidylethanol was positively associated with A1AT (P < .050). The PEth and activated-senescent CD8+ were associated with bacterial ß-diversity (P < .050) and positively associated with the relative abundance of coabundant Prevotellaceae members (q < .100). CONCLUSIONS: Alcohol use among PWH is associated with CD8+ T-cell late differentiation, intestinal leak, and dysbiosis. Alcohol-associated dysbiosis is implicated in CD8+ T-cell senescence.

Alcohol-associated intestinal dysbiosis impairs pulmonary host defense against Klebsiella pneumoniae.

Chronic alcohol consumption perturbs the normal intestinal microbial communities (dysbiosis). To investigate the relationship between alcohol-mediated dysbiosis and pulmonary host defense we developed a fecal adoptive transfer model, which allows us to investigate the impact of alcohol-induced gut dysbiosis on host immune response to an infectious challenge at a distal organ, independent of prevailing alcohol use. Male C57BL/6 mice were treated with a cocktail of antibiotics (ampicillin, gentamicin, neomycin, vancomycin, and metronidazole) via daily gavage for two weeks. A separate group of animals was fed a chronic alcohol (or isocaloric dextrose pair-fed controls) liquid diet for 10 days. Microbiota-depleted mice were recolonized with intestinal microbiota from alcohol-fed or pair-fed (control) animals. Following recolonization groups of mice were sacrificed prior to and 48 hrs. post respiratory infection with Klebsiella pneumoniae. Klebsiella lung burden, lung immunology and inflammation, as well as intestinal immunology, inflammation, and barrier damage were examined. Results showed that alcohol-associated susceptibility to K. pneumoniae is, in part, mediated by gut dysbiosis, as alcohol-naïve animals recolonized with a microbiota isolated from alcohol-fed mice had an increased respiratory burden of K. pneumoniae compared to mice recolonized with a control microbiota. The increased susceptibility in alcohol-dysbiosis recolonized animals was associated with an increase in pulmonary inflammatory cytokines, and a decrease in the number of CD4+ and CD8+ T-cells in the lung following Klebsiella infection but an increase in T-cell counts in the intestinal tract following Klebsiella infection, suggesting intestinal T-cell sequestration as a factor in impaired lung host defense. Mice recolonized with an alcohol-dysbiotic microbiota also had increased intestinal damage as measured by increased levels of serum intestinal fatty acid binding protein. Collectively, these results suggest that alterations in the intestinal immune response as a consequence of alcohol-induced dysbiosis contribute to increased host susceptibility to Klebsiella pneumonia.

The respiratory tract microbial biogeography in alcohol use disorder.

Individuals with alcohol use disorders (AUDs) are at an increased risk of pneumonia and acute respiratory distress syndrome. Data of the lung microbiome in the setting of AUDs are lacking. The objective of this study was to determine the microbial biogeography of the upper and lower respiratory tract in individuals with AUDs compared with non-AUD subjects. Gargle, protected bronchial brush, and bronchoalveolar lavage specimens were collected during research bronchoscopies. Bacterial 16S gene sequencing and phylogenetic analysis was performed, and the alterations to the respiratory tract microbiota and changes in microbial biogeography were determined. The microbial structure of the upper and lower respiratory tract was significantly altered in subjects with AUDs compared with controls. Subjects with AUD have greater microbial diversity [ P < 0.0001, effect size = 16 ± 1.7 observed taxa] and changes in microbial species relative abundances. Furthermore, microbial communities in the upper and lower respiratory tract displayed greater similarity in subjects with AUDs. Alcohol use is associated with an altered composition of the respiratory tract microbiota. Subjects with AUDs demonstrate convergence of the microbial phylogeny and taxonomic communities between distinct biogeographical sites within the respiratory tract. These results support a mechanistic pathway potentially explaining the increased incidence of pneumonia and lung diseases in patients with AUDs.

Lifetime alcohol use among persons living with HIV is associated with frailty.

BACKGROUND: The average lifespan of persons living with HIV (PLWH) on antiretroviral therapy approximates the general population. However, PLWH are susceptible to early aging and frailty. Behaviors such as alcohol consumption may contribute to frailty among PLWH. OBJECTIVE: To determine the relationships between recent and lifetime alcohol use and frailty among PLWH. DESIGN: Cross-sectional, prospective cohort study of in-care PLWH (n = 365) participating in the New Orleans Alcohol Use in HIV Study. METHODS: Recent alcohol exposure was measured by the 30-day alcohol timeline follow-back (TLFB) assessment and by whole-blood-spot phosphatidylethanol (PEth) quantitation. Lifetime alcohol exposure (LAE) was estimated by a modified lifetime drinking history instrument. Frailty was assessed by a 58-item deficit index (DI58) and the phenotypic frailty index (PFI). The Veterans Aging Cohort Study Risk Index 2.0 was calculated. RESULTS: Using generalized linear regression, LAE was positively associated with the DI58 (95% CI 0.001--0.006) and PFI severity (95% CI 0.004--0.023) after adjustment for age and other factors. Conversely, recent alcohol exposure was negatively associated with the DI58 [TLFB 95% CI: (-0.126 to -0.034), PEth: (-0.163 to -0.058)] and PFI severity [TLFB 95% CI (-0.404 to -0.015), PEth (-0.406 to 0.034)]. The VACS was not associated with alcohol use. Median per-decade alcohol exposure peaked in the second decade and tapered with aging thereafter. Increasing LAE and decreasing TLFB were co-associated with a specific subset of health deficits. CONCLUSION: Lifetime alcohol use is positively associated with frailty among PLWH. Specific health deficits may discourage alcohol consumption in some PLWH.

Biological Aging and the Human Gut Microbiota.

The human gastrointestinal microbiota plays a key homeostatic role in normal functioning of physiologic processes commonly undermined by aging. We used a previously validated 34-item frailty index (FI34) to identify changes in gut microbiota community structure associated with biological age of community-dwelling adults. Stool 16S rRNA cDNA libraries from 85 subjects ranging in age (43-79) and FI34 score (0-0.365) were deep sequenced, denoised, and clustered using DADA2. Subject biological age but not chronological age correlated with a decrease in stool microbial diversity. Specific microbial genera were differentially abundant in the lower, middle, and upper 33rd percentiles of biological age. Using Sparse Inverse Covariance Estimation for Ecological Association and Statistical Inference (SPIEC-EASI) and Weighted Gene Co-Expression Network Analysis (WGCNA), we identified modules of coabundant microbial genera that distinguished biological from chronological aging. A biological age-associated module composed of Eggerthella, Ruminococcus, and Coprobacillus genera was robust to correction for subject age, sex, body mass index, antibiotic usage, and other confounders. Subject FI34 score positively correlated with the abundance of this module, which exhibited a distinct inferred metagenome as predicted by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). We conclude that increasing biological age in community-dwelling adults is associated with gastrointestinal dysbiosis.

Irritant activation of epithelial cells is mediated via protease-dependent EGFR activation.

Although numerous studies have examined in vivo and in vitro effects of irritants, most focused on events developing hours to days after exposure. Molecular events occurring immediately after skin contact remain incompletely defined. Characterization of early events could lead to the identification of key molecular signals necessary for the production of inflammatory mediators responsible for the signs and symptoms of irritant contact dermatitis (ICD). HaCaT cells treated with sodium lauryl sulfate (SLS), a model irritant, were used to examine early molecular events of ICD. Western analysis showed SLS-mediated induction of early growth response-1 (egr-1), a transcription factor capable of regulating hallmarks of ICD such as angiogenesis, hyperproliferation, and inflammation. Additionally, de novo egr-1 expression was commensurate with transcriptional activation of egr-1 mRNA and heteronuclear RNA. Use of pharmacological inhibitors demonstrated that SLS-induced egr-1 was dependent on MEK1/p44/42 ERK, but not on p38 or JNK signaling. The EGFR inhibitor PD168393 and the metalloprotease inhibitor TAPI-2 both inhibited SLS-induced egr-1. Finally, small interfering RNA silencing of the EGFR diminished SLS-induced egr-1 mRNA. These studies suggest a role of the EGFR in SLS signaling as well as a, to our knowledge, previously unreported association between ICD and EGFR induction of egr-1.