Association of circulating adipokines with metabolic measures among people with HIV: Moderating effects of alcohol use.

BACKGROUND: People with HIV (PWH) are at increased risk for cardiometabolic comorbidities. We have reported that lifetime alcohol use among people with HIV (PWH) is associated with increased risk for metabolic syndrome. Dysfunctional adipose tissue and altered circulating adipokines mediate metabolic dysregulation. The objective of this study was to determine the associations of circulating adipokine concentration with metabolic measures, and the moderating effects of lifetime and recent alcohol use in PWH. METHODS: This is a cross-sectional analysis of data from 357 PWH at their baseline visit of the longitudinal New Orleans Alcohol and HIV (NOAH) study. The concentrations of four circulating adipokines (adiponectin, leptin, resistin, and fatty acid-binding protein 4 [FABP4]) and their associations with five metabolic measures (triglycerides, cholesterol, Hemoglobin A1c, Homeostatic Model Assessment for Insulin Resistance, and metabolic syndrome) were examined. RESULTS: Higher circulating adiponectin was associated with increased odds of normal triglyceride, cholesterol, and Hemoglobin A1c levels. Increased leptin and FABP4 concentrations were associated with decreased odds of normal triglyceride and cholesterol levels. Increased leptin and FABP4 concentrations were associated with increased odds of insulin resistance and meeting criteria for metabolic syndrome. Increased circulating resistin concentration was associated with decreased odds of normal triglyceride levels and increased odds of meeting criteria for metabolic syndrome. Additionally, among PWH with increased lifetime alcohol use, higher adiponectin concentration was associated with decreased odds of meeting criteria for metabolic syndrome. CONCLUSIONS: These data suggest the interplay between adiponectin, leptin, FABP4, and resistin may contribute to metabolic stability among PWH. Moreover, lifetime, but not recent, alcohol use moderates the relationship between adipokines and metabolic measures. These data highlight the relevance of functional adipose tissue mass and associated circulating adipokine levels in maintaining metabolic homeostasis, and its moderation by lifetime alcohol consumption.

Effects of Limosilactobacillus reuteri strains PTA-126787 and PTA-126788 on intestinal barrier integrity and immune homeostasis in an alcohol-induced leaky gut model.

Intestinal barrier is a first line of defense that prevents entry of various harmful substances from the lumen into the systemic environment. Impaired barrier function with consequent translocation of harmful substances into systemic circulation ("leaky gut") is a central theme in many gastrointestinal, autoimmune, mental, and metabolic diseases. Probiotics have emerged as a promising strategy to maintain intestinal integrity and address "leaky gut". Using in silico, in vitro and avian in vivo analyses, we previously showed that two novel L. reuteri strains, PTA-126787 (L. reuteri 3630) and PTA-126788 (L. reuteri 3632), isolated from broiler chickens possess favorable safety profiles. Consistent with a recent study, here we show that L. reuteri 3630 and 3632 are phylogenetically similar to human L. reuteri strains. Daily administration of high doses of L. reuteri 3630 and 3632 to Sprague Dawley rats for 28 days was found to be safe with no adverse effects. More importantly, administration of L. reuteri 3630 and 3632 significantly reduced markers associated with alcohol-induced leaky gut, by downregulating inflammatory cytokines and upregulating anti-inflammatory cytokines in an alcohol model of leaky gut in mice. While L. reuteri 3630 cells and supernatant showed no activation, L. reuteri 3632 cells but not supernatant showed activation of AhR, a key transcription factor that regulates gut and immune homeostasis. L. reuteri 3630 is creamish white in morphology typical of Lactobacillus species and L. reuteri 3632 displays a unique orange pigmentation, which was stable even after passaging for 480 generations. We identified a rare polyketide biosynthetic gene cluster in L. reuteri 3632 that likely encodes for the orange-pigmented secondary metabolite. Similar to L. reuteri 3632 cells, the purified orange metabolite activated AhR. All together, these data provide evidence on the phylogenetic relatedness, safety, efficacy, and one of the likely mechanisms of action of L. reuteri 3630 and 3632 for potential probiotic applications to address "leaky gut" and associated pathologies in humans.

Effects of E-Cigarettes on the Lung and Systemic Metabolome in People with HIV.

The popularity of e-cigarettes (vaping) has soared, creating a public health crisis among teens and young adults. Chronic vaping can induce gut inflammation and reduce intestinal barrier function through the production of the proinflammatory molecule hydrogen sulfide (H2S). This is particularly concerning for people with HIV (PWH) as they already face impaired immune function and are at a higher risk for metabolic dysregulation, diabetes, and chronic liver disease. Furthermore, PWH experience unhealthy behaviors, making it crucial to understand the systemic metabolic dysregulation and pathophysiological mechanisms associated with vaping in this population. Here, we employed liquid chromatography-mass spectrometry (LC-MS)-based metabolomics to investigate the upper respiratory, circulation, and gut metabolic profiles of PWH who vape (n = 7) and smoke combustible tobacco/marijuana (n = 6) compared to control participants who did not vape or smoke (n = 10). This hypothesis-generating exploratory study revealed systemic alterations in purine, neurotransmitter, and vitamin B metabolisms and tissue-specific changes in inflammatory pathways and cryptic sulfur cycling associated with vaping and combustible tobacco/marijuana smoking in PWH. In addition, this study provides the first link between microbial-derived metabolite 2,3-dihydroxypropane-1-sulfonate (DHPS) and vaping/smoking (tobacco and marijuana)-induced metabolic dyshomeostasis in the gut. These findings highlight the importance of identifying the full biological and clinical significance of the physiological changes and risks associated with vaping.

Moderate-to-severe cognitive impairment is associated with both recent and chronic alcohol misuse in people with HIV: The New Orleans alcohol use in HIV (NOAH) study.

BACKGROUND: Human immunodeficiency virus (HIV) profoundly impacts the nervous system, leading to neurological deficits including HIV-associated neurocognitive disorder (HAND). HAND represents the most common neurological comorbidity among people with HIV (PWH), and alcohol use may exacerbate cognitive deficits, especially in vulnerable populations. This study investigated relationships between alcohol use and cognition in an underserved cohort of PWH, on the hypothesis that alcohol misuse exacerbates cognitive deficits. METHODS: Data collected from participants (n = 259; 66.7% male; mean age 52 ± 10 years) enrolled in the New Orleans Alcohol Use in HIV (NOAH) study were utilized for cross-sectional analysis. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA), and alcohol use was comprehensively measured using four metrics: the Alcohol Use Disorders Identification Test (AUDIT), 30-day timeline follow back (TLFB), lifetime drinking history, and phosphatidylethanol (PEth) levels. RESULTS: The average MoCA score among participants was 20.7 ± 4.5, with 86.5% demonstrating cognitive impairment (MoCA < 26). Individuals with MoCA scores below 18 (moderately or severely cognitively impaired) had a higher frequency of recent severe alcohol misuse and greater lifetime alcohol consumption. Participants at increased risk for AUD (AUDIT ≥ 16) also had worse global cognition and memory task performance than those with lower AUDIT scores; this was particularly true among those aged 50 and older. Analysis of the MoCA sub-score data indicated that participants with increased AUD risk had impairments in the cognitive domains of language and memory. CONCLUSIONS: Our findings demonstrate a high prevalence of cognitive impairment in the NOAH cohort and suggest that alcohol misuse contributes to global cognitive deficits in PWH, especially among individuals aged 50 and older. Further exploration of the impact of alcohol use on specific cognitive domains, including memory and language, should incorporate additional cognitive tasks. These findings highlight the importance of considering alcohol use and AUD risk as significant factors that may exacerbate cognitive deficits in vulnerable populations, including older PWH.

The Impact of Childhood Adversity on Life Course Alcohol Use Patterns and Health Status Among People Living with HIV.

Adverse childhood experiences (ACEs) and financial hardship are associated with increased likelihood of heavier alcohol use and health challenges in adulthood among persons living with HIV (PWH). We examined whether retrospectively captured lifetime drinking trajectories are a pathway through which childhood hardships affect current health in a sample of 365 adult PWH. Childhood economic hardship and ACEs were used as main predictors. Measures of alcohol use included age at first drink and lifetime drinking trajectories. Health indicators included health-related quality of life, frailty, number of comorbidities, and symptoms of anxiety, depression, and post-traumatic stress disorder (PTSD). Structural equation modeling (SEM) was applied to estimate both direct and indirect pathways between childhood hardship and physical and mental health. Participants were mostly male; Black (84%); and averaged 48 years of age. SEM results supported both direct and indirect pathways between childhood experiences and adult health. ACEs were connected to physical health directly and mental health both directly and indirectly through age at first drink and drinking heaviness during ages 10-20. Childhood economic hardship related to mental health indirectly through higher drinking levels during ages 10-20. Childhood adverse experiences, economic hardship, and early drinking patterns appear to accumulate, resulting in later life physical and mental health concerns for PWH. Findings support taking a life course approach to health. This includes considering individual trauma histories in HIV care engagement and taking preventative approaches which support the economic and social well-being of vulnerable children to improve health in subsequent decades.

Emerging concepts in alcohol, infection & immunity: A summary of the 2023 alcohol and immunology research interest group (AIRIG) meeting.

On December 8th 2023, the annual Alcohol and Immunology Research Interest Group (AIRIG) meeting was held at the University of Colorado Anschutz Medical Campus in Aurora, Colorado. The 2023 meeting focused broadly on how acute and chronic alcohol exposure leads to immune dysregulation, and how this contributes to damage in multiple tissues and organs. These include impaired lung immunity, intestinal dysfunction, autoimmunity, the gut-Central Nervous System (CNS) axis, and end-organ damage. In addition, diverse areas of alcohol research covered multiple pathways behind alcohol-induced cellular dysfunction, including inflammasome activation, changes in miRNA expression, mitochondrial metabolism, gene regulation, and transcriptomics. Finally, the work presented at this meeting highlighted novel biomarkers and therapeutic interventions for patients suffering from alcohol-induced organ damage.

Human Alcohol-Microbiota Mice have Increased Susceptibility to Bacterial Pneumonia.

Preclinical studies have shown that chronic alcohol abuse leads to alterations in the gastrointestinal microbiota that are associated with behavior changes, physiological alterations, and immunological effects. However, such studies have been limited in their ability to evaluate the direct effects of alcohol-associated dysbiosis. To address this, we developed a humanized alcohol-microbiota mouse model to systematically evaluate the immunological effects of chronic alcohol abuse mediated by intestinal dysbiosis. Germ-free mice were colonized with human fecal microbiota from individuals with high and low Alcohol Use Disorders Identification Test (AUDIT) scores and bred to produce human alcohol-associated microbiota or human control-microbiota F1 progenies. F1 offspring colonized with fecal microbiota from individuals with high AUDIT scores had increased susceptibility to Klebsiella pneumoniae and Streptococcus pneumoniae pneumonia, as determined by increased mortality rates, pulmonary bacterial burden, and post-infection lung damage. These findings highlight the importance of considering both the direct effects of alcohol and alcohol-induced dysbiosis when investigating the mechanisms behind alcohol-related disorders and treatment strategies.

The Role of Gut Dysbiosis in the Loss of Intestinal Immune Cell Functions and Viral Pathogenesis.

The gut microbiome plays a critical role in maintaining overall health and immune function. However, dysbiosis, an imbalance in microbiome composition, can have profound effects on various aspects of human health, including susceptibility to viral infections. Despite numerous studies investigating the influence of viral infections on gut microbiome, the impact of gut dysbiosis on viral infection and pathogenesis remains relatively understudied. The clinical variability observed in SARS-CoV-2 and seasonal influenza infections, and the presence of natural HIV suppressors, suggests that host-intrinsic factors, including the gut microbiome, may contribute to viral pathogenesis. The gut microbiome has been shown to influence the host immune system by regulating intestinal homeostasis through interactions with immune cells. This review aims to enhance our understanding of how viral infections perturb the gut microbiome and mucosal immune cells, affecting host susceptibility and response to viral infections. Specifically, we focus on exploring the interactions between gamma delta (γδ) T cells and gut microbes in the context of inflammatory viral pathogenesis and examine studies highlighting the role of the gut microbiome in viral disease outcomes. Furthermore, we discuss emerging evidence and potential future directions for microbiome modulation therapy in the context of viral pathogenesis.

Lifetime Alcohol Use Trajectories and Health Status Among Persons Living with HIV (PLWH).

OBJECTIVE: We characterized lifetime drinking trajectories among persons living with HIV (PLWH) and examined how trajectories are related to health. METHOD: Adults (ages 20-71) were recruited between 2015 and 2017 for a cohort study examining the impact of alcohol use on geriatric comorbidities in PLWH in New Orleans. The New Orleans Alcohol Use in HIV (NOAH) Study (n = 356; 68.8% male) included in-person interviews, anthropometric measurements, and biospecimen collection. Average monthly drinks per decade of life was derived from participants' reported average quantity and frequency of alcoholic beverages for each decade. Health indicators included CD4 count, viral load, health-related quality of life, frailty, comorbidities, body mass index, heavy drinking, anxiety, depression, and posttraumatic stress disorder. Participants also reported lifetime experiences with homelessness and incarceration. Latent curve modeling was applied in MPlus to derive lifetime drinking trajectories. Latent trajectory parameters were modeled as predictors of physical, mental, and social health, controlling for demographics. RESULTS: Alcohol consumption increased significantly between the teen years and midlife (31-40), declining thereafter through ages 50-60. Significant interindividual differences were observed in all trajectory parameters. Persons with higher starting points of alcohol consumption showed worse mental health (depression and anxiety) and social experiences (homelessness and incarceration history) at study baseline. A steeper increase in volume of alcohol consumption after ages 10-20 was associated with worse health-related quality of life, greater frailty and comorbidities, and greater odds of current heavy drinking. CONCLUSIONS: Understanding lifetime alcohol consumption patterns is important in addressing physical and mental health among adult PLWH.

Alcohol use, physical activity, and muscle strength moderate the relationship between body composition and frailty risk among people living with HIV.

BACKGROUND: Antiretroviral therapy has improved life expectancy among people living with HIV (PLWH). Despite increased longevity, PLWH are at increased risk of age-related comorbidities, including frailty. We examined the relationship between body composition and frailty among PLWH, and moderation of this relationship by substance use, physical activity (PA), and physical function. METHODS: Participants (n = 341; 71% male, 48 ± 10 years, body mass index (BMI) = 27.3 ± 7.0 kg/m2 ) enrolled in the New Orleans Alcohol Use in HIV (NOAH) study underwent measures of body composition, muscle strength, and gait speed. Whole blood phosphatidylethanol (PEth) was measured, and substance use and PA were self-reported. Frailty risk measures included the 58-Item Deficit Index (DI58) and the Veterans Aging Cohort Study (VACS) Index 1.0, where higher scores indicate greater frailty risk. RESULTS: Multivariable linear regression adjusted for age, sex, and race showed that higher fat-free mass index (FFMI), body fat (%), waist-to-hip ratio, and body mass index (BMI) ≥ 25.0 kg/m2 vs. < 25.0 kg/m2 were significantly (p < 0.05) associated with decreased frailty risk measured by the VACS Index, whereas adjusted analyses showed no association between body composition variables and the DI58 score. Recent alcohol use, muscle strength, and PA, but not lifetime alcohol use or gait speed, significantly moderated associations between body composition variables and frailty risk with medium-to-large effect sizes. Subgroup analyses revealed a negative relationship between DI58 and FFMI among people with PEth > 8 ng/ml and negative relationships of VACS Index with FFMI and WHR in people with lower muscle strength. Overweight or obese BMI categories were positively associated with DI58 in people with lower muscle strength or higher PA level but negatively associated in those with higher muscle strength. CONCLUSIONS: Our findings indicate that body composition has significant modulatory effects on frailty risk in PLWH, where obesity increases the risk of frailty and greater muscle mass may be protective, even in individuals who use alcohol. These results highlight the importance of considering body composition, physical activity, and physical function in assessing frailty risk in PLWH, particularly among individuals who use alcohol. Moreover, they support the implementation of physical activity interventions to ameliorate the risk of frailty in aging PLWH.

Alcohol Impairs Immunometabolism and Promotes Naïve T Cell Differentiation to Pro-Inflammatory Th1 CD4+ T Cells.

CD4+ T cell differentiation to pro-inflammatory and immunosuppressive subsets depends on immunometabolism. Pro-inflammatory CD4+ subsets rely on glycolysis, while immunosuppressive Treg cells require functional mitochondria for their differentiation and function. Previous pre-clinical studies have shown that ethanol (EtOH) administration increases pro-inflammatory CD4+ T cell subsets; whether this shift in immunophenotype is linked to alterations in CD4+ T cell metabolism had not been previously examined. The objective of this study was to determine whether ethanol alters CD4+ immunometabolism, and whether this affects CD4+ T cell differentiation. Naïve human CD4+ T cells were plated on anti-CD3 coated plates with soluble anti-CD28, and differentiated with IL-12 in the presence of ethanol (0 and 50 mM) for 3 days. Both Tbet-expressing (Th1) and FOXP3-expressing (Treg) CD4+ T cells increased after differentiation. Ethanol dysregulated CD4+ T cell differentiation by increasing Th1 and decreasing Treg CD4+ T cell subsets. Ethanol increased glycolysis and impaired oxidative phosphorylation in differentiated CD4+ T cells. Moreover, the glycolytic inhibitor 2-deoxyglucose (2-DG) prevented the ethanol-mediated increase in Tbet-expressing CD4+ T cells but did not attenuate the decrease in FOXP3 expression in differentiated CD4+ T cells. Ethanol increased Treg mitochondrial volume and altered expression of genes implicated in mitophagy and autophagosome formation (PINK1 and ATG7). These results suggest that ethanol impairs CD4+ T cell immunometabolism and disrupts mitochondrial repair processes as it promotes CD4+ T cell differentiation to a pro-inflammatory phenotype.

Cross sectional analysis of the effect of alcohol on pulmonary function in a cohort of men and women living with HIV.

People living with HIV (PLWH) are at increased risk for noncommunicable diseases such as lung disease in part due to opportunistic infections including pneumonia. HIV infection is associated with increased prevalence of impaired lung function and abnormal gas exchange. Alcohol use disorder (AUD) is exceedingly common in PLWH and is associated with higher risk of pneumonia in PLWH. Alcohol use may lead to lung damage through several mechanisms. Data on the long-term effect of AUD on pulmonary function in PLWH are sparse and conflicting. To evaluate this relationship, we conducted a cross-sectional analysis of adult PLWH in care in Louisiana. We hypothesized that chronic alcohol use would be associated with subsequent pulmonary dysfunction in a dose-dependent fashion. All participants performed standardized spirometry on study entry. In total, 350 participants with acceptable spirometry were included in this analysis. Thirty-one percent of participants were female. Women reported less lifetime alcohol use and less smoking; however, they reported more chronic respiratory symptoms. In adjusted models, total lifetime alcohol use was not associated with spirometry measures of pulmonary function. HIV-related variables (CD4 count and viral load) were also not associated with measures of pulmonary function. We then conducted sex-stratified analyses to eliminate residual confounding of sex and similarly found no association of total lifetime alcohol use and pulmonary function. We found no association of AUDIT score or early life alcohol use and pulmonary function. In latent class factor analysis, current heavy alcohol use was associated with lower measures of pulmonary function as compared to former heavy alcohol use. In summary, in this cohort of New Orleanian men and women living with HIV with robust measures of alcohol use, though total lifetime alcohol use and early life alcohol use were not associated with pulmonary function, current heavy alcohol use was associated with impaired pulmonary function.

Host innate and adaptive immunity shapes the gut microbiota biogeography.

The gut microbiota has a fundamental role in the development and the maturation of the host immune system. Both innate and adaptive immune cells have critical functions in microbial pathogen containment and clearance, but the regulation of the commensal microbiome ecosystem in the gastrointestinal tract by these major immune cell populations is incompletely defined. The role of specific innate and adaptive immune cell in the regulation of the microbiota in the intestinal tract biogeographically was investigated. Dendritic cells, macrophages, CD4+ T-cells, CD8+ T-cells, and B-cells were depleted using monoclonal antibodies and clodronate liposomes, and the microbial communities were determined by 16S rRNA gene sequencing. With specific immune cell depletion, distinct microbiota changes were observed. In general, immune cell depleted mice had higher microbiota richness and evenness at all gut anatomical sites. At each gut segment, samples from immune cell-depleted animals clustered away from the isotype/liposome control mice. This was especially dramatic for the small intestinal microbiota. Specifically, Enterobacteriaceae, Bacteroides acidifaciens, and Mucispirillum schaedleri were highly enriched in the mucosa and lumen of the small intestine in immune cell-deficient animals. Further, the mucosal microbiota had higher microbiota evenness compared with luminal microbiota at all gut segments, and the UniFrac distance between B cell depleted and isotype control mice was the largest in the duodenum followed by the ileum and colon. Taken together, the data suggest that innate and adaptive immune cells specifically contribute to the regulation of the gut microbiota's biogeographical distribution along the gastrointestinal tract, and microbiota in the duodenum mucosa are more responsive to host immune changes compared with other anatomical sites.

Associations of Binge Drinking and Heavy Alcohol Use on Sugar and Fat Intake in a Cohort of Southern People Living with HIV.

AIMS: To assess whether binge drinking and heavy alcohol use are associated with increased sugar and fat consumption among a Southern cohort of people living with HIV (PWH). METHODS: This was a cross-sectional analysis of PWH enrolled in the New Orleans Alcohol use in HIV (NOAH) Study (n = 215). Binge and heavy drinking were identified through a 30-day Alcohol Timeline-Followback and dietary intake was assessed through a 24-hour dietary recall. RESULTS: Participants were 65.4% male, 83.3% Black, with a mean age of 49.2 ± 9.9. Heavy drinkers consumed more total calories than abstainers (P = 0.035) and low-to-moderate drinkers (P = 0.024), and binge drinkers consumed more calories than non-binge drinkers (P = 0.025). Binge and heavy drinkers had significantly higher intake of total and saturated fat in grams. However, substantially increased caloric intake among these participants led to non-significant associations for alcohol use with high total and saturated fat intake as a percent of total energy intake (%TEI). Binge drinkers had lower odds of consuming high sugar as a %TEI (odds ratio: 0.31 [0.14, 0.68]). Additionally, sugar intake predicted total and saturated fat intake, and this association was slightly higher among binge drinkers (total fat P-value: 0.12). CONCLUSIONS: In this population of PWH, while binge and heavy drinking predicted higher caloric and fat intake in grams, binge drinkers were less likely to consume a high-sugar diet. This analysis suggests that interventions focused on reduced alcohol use may be especially beneficial in reducing metabolic disease burden in PWH if supplemented with information on incorporating lower energy-dense foods with reduced fat.

Gut Microbiota Composition and Predicted Microbial Metabolic Pathways of Obesity Prone and Obesity Resistant Outbred Sprague-Dawley CD Rats May Account for Differences in Their Phenotype.

Like humans, outbred Sprague-Dawley CD rats exhibit a polygenic pattern of inheritance of the obese phenotype and not all individuals exposed to a high calorie intake develop obesity. We hypothesized that differences in gut microbiota composition account for phenotype differences between obese prone (OP) and obese resistant (OR) rats. We studied the gut microbiota composition of OPand OR rats after a high fat (HF) diet and how they respond to fermentation of resistant starch (RS). In phase 1 of the study 28 OP and 28 OR rats were fed a HF diet. In order to determine causal role of microbiota on phenotypes, In phase 2, a microbiota transplant between the two phenotypes was performed before switching all rats to a HF diet supplemented with 20% RS. We determined microbiota composition by 16S sequencing and predicted microbiota function by PICRUSt2. Despite a similar calorie intake, in phase 2 OP rats gained more weight and accumulated more abdominal fat in both phase 1 and 2 compared to OR rats (P < 0.001; n = 6). The OP rats fermented RS more robustly compared with OR rats with an increase in total bacteria, short chain fatty acids, and increased weight of the cecum, but microbiota of OP rats had much lower alpha diversity and evenness. The microbiota of OP rats, had higher amounts of bacteria from order Bacteroidales, specifically family Muribaculaceae (S24-7), which is known to possess several starch degrading enzymes and was reported in previous studies to increase with fermentation of RS. The OR rats fermented RS less but had higher bacterial diversity and evenness and had significantly higher bacterial counts from phylum Firmicutes particularly order Clostridiales, genus Clostridium and an uncultured bacterium of the genus Akkermansia. The microbiota of OR rats had enhanced bacterial chemotaxis, phosphotransferase system (PTS), and fatty acid biosynthesis compared to OP rats whose microbiota had higher glycan degradation and LPS biosynthesis pathways. The microbiota transplant did not change obesity phenotype or microbiota composition. In conclusion, a higher alpha-diversity and evenness of the microbiota and higher proportions of Clostridiales and Akkermansia in OR rats were associated with a better metabolic phenotype with lower body fat. However, robust RS fermentation caused a lower diversity and evenness and did not result in a leaner phenotype.

Pulmonary immune cell trafficking promotes host defense against alcohol-associated Klebsiella pneumonia.

The intestinal microbiota generates many different metabolites which are critical for the regulation of host signaling pathways. In fact, a wide-range of diseases are associated with increased levels of local or systemic microbe-derived metabolites. In contrast, certain bacterial metabolites, such as tryptophan metabolites, are known to contribute to both local and systemic homeostasis. Chronic alcohol consumption is accompanied by alterations to intestinal microbial communities, and their functional capacities. However, little is known about the role of alcohol-associated dysbiosis on host defense against bacterial pneumonia. Our previous work using fecal transplantation demonstrated that alcohol-associated intestinal dysbiosis, independent of ethanol consumption, increased susceptibility to Klebsiella pneumonia. Here, we demonstrate that intestinal microbiota treatments mitigate the increased risk of alcohol-associated pneumonia. Treatment with the microbial metabolite indole or with probiotics reduced pulmonary and extrapulmonary bacterial burden, restored immune responses, and improved cellular trafficking required for host defense. Protective effects were, in part, mediated by aryl hydrocarbon receptors (AhR), as inhibition of AhR diminished the protective effects. Thus, alcohol appears to impair the production/processing of tryptophan catabolites resulting in immune dysregulation and impaired cellular trafficking. These data support microbiota therapeutics as novel strategies to mitigate the increased risk for alcohol-associated bacterial pneumonia.

Alcohol-associated intestinal dysbiosis alters mucosal-associated invariant T-cell phenotype and function.

BACKGROUND: Chronic alcohol consumption is associated with a compromised innate and adaptive immune responses to infectious disease. Mucosa-associated invariant T (MAIT) cells play a critical role in antibacterial host defense. However, whether alcohol-associated deficits in innate and adaptive immune responses are mediated by alterations in MAIT cells remains unclear. METHODS: To investigate the impact of alcohol on MAIT cells, mice were treated with binge-on-chronic alcohol for 10 days and sacrificed at day 11. MAIT cells in the barrier organs (lung, liver, and intestine) were characterized by flow cytometry. Two additional sets of animals were used to examine the involvement of gut microbiota on alcohol-induced MAIT cell changes: (1) Cecal microbiota from alcohol-fed (AF) mice were adoptive transferred into antibiotic-pretreated mice and (2) AF mice were treated with antibiotics during the experiment. MAIT cells in the barrier organs were measured via flow cytometry. RESULTS: Binge-on-chronic alcohol feeding led to a significant reduction in the abundance of MAIT cells in the barrier tissues. However, CD69 expression on tissue-associated MAIT cells was increased in AF mice compared with pair-fed (PF) mice. The expression of Th1 cytokines and the corresponding transcriptional factor was tissue specific, showing downregulation in the intestine and increases in the lung and liver in AF animals. Transplantation of fecal microbiota from AF mice resulted in a MAIT cell profile aligned to that of AF mouse donor. Antibiotic treatment abolished the MAIT cell differences between AF and PF animals. CONCLUSION: MAIT cells in the intestine, liver, and lung are perturbed by alcohol use and these changes are partially attributable to alcohol-associated dysbiosis. MAIT cell dysfunction may contribute to alcohol-induced innate and adaptive immunity and consequently end-organ pathophysiology.

Dysregulation of IL-17/IL-22 Effector Functions in Blood and Gut Mucosal Gamma Delta T Cells Correlates With Increase in Circulating Leaky Gut and Inflammatory Markers During cART-Treated Chronic SIV Infection in Macaques.

HIV-associated inflammation has been implicated in the premature aging and increased risk of age-associated comorbidities in cART-treated individuals. However, the immune mechanisms underlying the chronic inflammatory state of cART-suppressed HIV infection remain unclear. Here, we investigated the role of γδT cells, a group of innate IL-17 producing T lymphocytes, in the development of systemic inflammation and leaky gut phenotype during cART-suppressed SIV infection of macaques. Plasma levels of inflammatory mediators, intestinal epithelial barrier disruption (IEBD) and microbial translocation (MT) biomarkers, and Th1/Th17-type cytokine functions were longitudinally assessed in blood and gut mucosa of SIV-infected, cART-suppressed macaques. Among the various gut mucosal IL-17/IL-22-producing T lymphocyte subsets including Th17, γδT, CD161+ CD8+ T, and MAIT cells, a specific decline in the Vδ2 subset of γδT cells and impaired IL-17/IL-22 production in γδT cells significantly correlated with the subsequent increase in plasma IEBD/MT markers (IFABP, LPS-binding protein, and sCD14) and pro-inflammatory cytokines (IL-6, IL-1ß, IP10, etc.) despite continued viral suppression during long-term cART. Further, the plasma inflammatory cytokine signature during long-term cART was distinct from acute SIV infection and resembled the inflammatory cytokine profile of uninfected aging (inflammaging) macaques. Overall, our data suggest that during cART-suppressed chronic SIV infection, dysregulation of IL-17/IL-22 cytokine effector functions and decline of Vδ2 γδT cell subsets may contribute to gut epithelial barrier disruption and development of a distinct plasma inflammatory signature characteristic of inflammaging. Our results advance the current understanding of the impact of chronic HIV/SIV infection on γδT cell functions and demonstrate that in the setting of long-term cART, the loss of epithelial barrier-protective functions of Vδ2 T cells and ensuing IEBD/MT occurs before the hallmark expansion of Vδ1 subsets and skewed Vδ2/Vδ1 ratio. Thus, our work suggests that novel therapeutic approaches toward restoring IL-17/IL-22 cytokine functions of intestinal Vδ2 T cells may be beneficial in preserving gut epithelial barrier function and reducing chronic inflammation in HIV-infected individuals.

Feature Selection Algorithms Enhance the Accuracy of Frailty Indexes as Measures of Biological Age.

Biological age captures some of the variance in life expectancy for which chronological age is not accountable, and it quantifies the heterogeneity in the presentation of the aging phenotype in various individuals. Among the many quantitative measures of biological age, the mathematically uncomplicated frailty/deficit index is simply the proportion of the total health deficits in various health items surveyed in different individuals. We used 3 different statistical methods that are popular in machine learning to select 17-28 health items that together are highly predictive of survival/mortality, from independent study cohorts. From the selected sets, we calculated frailty indexes and Klemera-Doubal's biological age estimates, and then compared their mortality prediction performance using Cox proportional hazards regression models. Our results indicate that the frailty index outperforms age and Klemera-Doubal's biological age estimates, especially among the oldest old who are most prone to biological aging-caused mortality. We also showed that a DNA methylation index, which was generated by applying the frailty/deficit index calculation method to 38 CpG sites that were selected using the same machine learning algorithms, can predict mortality even better than the best performing frailty index constructed from health, function, and blood chemistry.

A Novel FACS-Based Workflow for Simultaneous Assessment of RedOx Status, Cellular Phenotype, and Mitochondrial Genome Stability.

Intracellular reduction-oxidation (RedOx) status mediates a myriad of critical biological processes. Importantly, RedOx status regulates the differentiation of hematopoietic stem and progenitor cells (HSPCs), mesenchymal stromal cells (MSCs) and maturation of CD8+ T Lymphocytes. In most cells, mitochondria are the greatest contributors of intracellular reactive oxygen species (ROS). Excess ROS leads to mitochondrial DNA (mtDNA) damage and protein depletion. We have developed a fluorescence-activated cell sorting (FACS)-based protocol to simultaneously analyze RedOx status and mtDNA integrity. This simultaneous analysis includes measurements of ROS (reduced glutathione (GSH)), ATP5H (nuclear encoded protein), MTCO1 (mitochondrial DNA encoded protein), and cell surface markers to allow discrimination of different cell populations. Using the ratio of MTCO1 to ATP5H median fluorescence intensity (MFI), we can gain an understanding of mtDNA genomic stability, since MTCO1 levels are decreased when mtDNA becomes significantly damaged. Furthermore, this workflow can be optimized for sorting cells, using any of the above parameters, allowing for downstream quantification of mtDNA genome copies/nucleus by quantitative PCR (qPCR). This unique methodology can be used to enhance analyses of the impacts of pharmacological interventions, as well as physiological and pathophysiological processes on RedOx status along with mitochondrial dynamics in most cell types.