Associations of cocaine use and HIV infection with the intestinal microbiota, microbial translocation, and inflammation

Role of Inflammasomes in HIV-1 and Drug Abuse Mediated Neuroinflammaging

Despite the effectiveness of combined antiretroviral therapy (cART) in suppressing virus replication, chronic inflammation remains one of the cardinal features intersecting HIV-1, cART, drug abuse, and likely contributes to the accelerated neurocognitive decline and aging in people living with HIV-1 (PLWH) that abuse drugs. It is also estimated that ~30–60% of PLWH on cART develop cognitive deficits associated with HIV-1-associated neurocognitive disorders (HAND), with symptomatology ranging from asymptomatic to mild, neurocognitive impairments. Adding further complexity to HAND is the comorbidity of drug abuse in PLWH involving activated immune responses and the release of neurotoxins, which, in turn, mediate neuroinflammation. Premature or accelerated aging is another feature of drug abusing PLWH on cART regimes. Emerging studies implicate the role of HIV-1/HIV-1 proteins, cART, and abused drugs in altering the inflammasome signaling in the central nervous system (CNS) cells. It is thus likely that exposure of these cells to HIV-1/HIV-1 proteins, cART, and/or abused drugs could have synergistic/additive effects on the activation of inflammasomes, in turn, leading to exacerbated neuroinflammation, ultimately resulting in premature aging referred to as “inflammaging” In this review, we summarize the current knowledge of inflammasome activation, neuroinflammation, and aging in central nervous system (CNS) cells such as microglia, astrocytes, and neurons in the context of HIV-1 and drug abuse.

The gut microbiome and frailty

The human microbiome is constituted by an extensive network of organisms that lie at the host/environment interface and transduce signals that play vital roles in human health and disease across the lifespan. Frailty is a critical aging-related syndrome marked by diminished physiological reserve and heightened vulnerability to stress, predictive of major adverse clinical outcomes including death. While recent studies suggest the microbiome may impact key pathways critical to frailty pathophysiology, direct evaluation of the microbiome-frailty relationship remains limited. In this article, we review the complex interplay of biological, behavioral, and environmental factors that may influence shifts in gut microbiome composition and function in aging populations and the putative implications of such shifts for progression to frailty. We discuss HIV infection as a key prototype for elucidating the complex pathways via which the microbiome may precipitate frailty. Finally, we review considerations for future research efforts.

Intergenerational transmission of the effects of maternal exposure to childhood maltreatment on offspring obesity risk: A fetal programming perspective

Childhood obesity constitutes a major global public health challenge. A substantial body of evidence suggests that conditions and states experienced by the embryo/fetus in utero can result in structural and functional changes in cells, tissues, organ systems and homeostatic set points related to obesity. Furthermore, growing evidence suggests that maternal conditions and states experienced prior to conception, such as stress, obesity and metabolic dysfunction, may spill over into pregnancy and influence those key aspects of gestational biology that program offspring obesity risk. In this narrative review, we advance a novel hypothesis and life-span framework to propose that maternal exposure to childhood maltreatment may constitute an important and as-yet-underappreciated risk factor implicated in developmental programming of offspring obesity risk via the long-term psychological, biological and behavioral sequelae of childhood maltreatment exposure. In this context, our framework considers the key role of maternal-placental-fetal endocrine, immune and metabolic pathways and also other processes including epigenetics, oocyte mitochondrial biology, and the maternal and infant microbiomes. Finally, our paper discusses future research directions required to elucidate the nature and mechanisms of the intergenerational transmission of the effects of maternal childhood maltreatment on offspring obesity risk.

Antibiotic-Driven Gut Microbiome Disorder Alters the Effects of Sinomenine on Morphine-Dependent Zebrafish

Morphine is one of the most severely abused drugs in the world. Previous research on morphine addiction has focused on the central nervous system (CNS). Studies have shown that a two-way regulation of the brain and gut microbiota (GM), suggesting a link between GM and CNS disease. However, the functional mechanism underlying the relationship between intestinal flora and morphine dependence is unclear. In this study, the effect of sinomenine on morphine addiction was evaluated based on the microbiota-gut-brain axis (MGBA). The results show that the GM plays an important role in morphine dependence. Morphine treatment induced zebrafish conditional position preference (CPP), and significantly changed zebrafish GM characteristics and the expression of MGBA-related genes in the zebrafish brain and intestine. Importantly, sinomenine, an alkaloid with a similar structure to morphine, can reverse these morphine-induced changes. Subsequently, morphine-dependent CPP training was performed after antibiotic administration. After antibiotic treatment, zebrafish CPP behavior, the composition and proportions of the zebrafish GM, and the expression of MGBA-related genes in zebrafish were changed. More interestingly, sinomenine was no longer effective in treating morphine dependence, indicating that antibiotic-driven intestinal flora imbalance alters the efficacy of sinomenine on morphine-dependent zebrafish. This study confirms that the MGBA is bidirectionally regulated, highlighting the key role of the GM in the formation and treatment of morphine dependence, and may provide new treatment strategies for using traditional Chinese medicine to treat drug addiction.

Targeting the microbiota in pharmacology of psychiatric disorders

There is increasing interest in the role of the gut microbiota in health and disease. In particular, gut microbiota influences the Central Nervous System (CNS) development and homeostasis through neural pathways or routes involving the immune and circulatory systems. The CNS, in turn, shapes the intestinal flora through endocrine or stress-mediated responses. These overall bidirectional interactions, known as gut microbiota-brain axis, profoundly affect some brain functions, such as neurogenesis and the production of neurotransmitters, up to influence behavioral aspects of healthy subjects. Consequently, a dysfunction within this axis, as observed in case of dysbiosis, can have an impact on the behavior of a given individual (e.g. anxiety and depression) or on the development of pathologies affecting the CNS, such as autism spectrum disorders and neurodegenerative diseases (e.g. Alzheimer's disease and Parkinson's disease). It should be considered that the whole microbiota has a significant role not only on aspects concerning human physiology, such as harvesting of nutrients and energy from the ingested food or production of a wide range of bioactive compounds, but also has positive effects on the gastrointestinal barrier function and actively contributes to the pharmacokinetics of several compounds including neuropsychiatric drugs. Indeed, the microbiota is able to affect drug absorption and metabolism up to have an impact on drug activity and/or toxicity. On the other hand, drugs are able to shape the human gut microbiota itself, where these changes may contribute to their pharmacologic profile. Therefore, the emerging picture on the complex drug-microbiota bidirectional interplay will have considerable implications in the future not only in terms of clinical practice but also, upstream, on drug development.

The role of the gut microbiome in opioid use

Although the gut and brain are separate organs, they communicate with each other via trillions of intestinal bacteria that collectively make up one's gut microbiome. Findings from both humans and animals support a critical role of gut microbes in regulating brain function, mood, and behavior. Gut bacteria influence neural circuits that are notably affected in addiction-related behaviors. These include circuits involved in stress, reward, and motivation, with substance use influencing gut microbial abnormalities, suggesting significant gut-brain interactions in drug addiction. Given the overwhelming rates of opioid overdose deaths driven by abuse and addiction, it is essential to characterize mechanisms mediating the abuse potential of opioids. We discuss in this review the role of gut microbiota in factors that influence opioid addiction, including incentive salience, reward, tolerance, withdrawal, stress, and compromised executive function. We present clinical and preclinical evidence supporting a bidirectional relationship between gut microbiota and opioid-related behaviors by highlighting the effects of opioid use on gut bacteria, and the effects of gut bacteria on behavioral responses to opioids. Further, we discuss possible mechanisms of this gut-brain communication influencing opioid use. By clarifying the relationship between the gut microbiome and opioid-related behaviors, we improve understanding on mechanisms mediating reward-, motivation-, and stress-related behaviors and disorders, which may contribute to the development of effective, targeted therapeutic interventions in opioid dependence and addiction.

Differences in Gut Microbial Diversity are Driven by Drug Use and Drug Cessation by Either Compulsory Detention or Methadone Maintenance Treatment

In this work, we investigate differences in gut microbial diversity driven by drug use or by the widely used methods for drug cessation: methadone maintenance treatment (MMT) and compulsory detention (CD). Methods: 99 participants (28 CD participants, 16 MMT patients, 27 drug users, and 28 healthy controls) were selected using strict inclusion criteria. Nutritional intake and gut microbial diversity were analyzed with bioinformatics tools and SPSS 20.0. Results: Alpha diversity was not significantly different among groups, whereas beta diversity of gut microbiota and nutrient intake were significantly higher among MMT patients. Taxa were unevenly distributed between groups, with drug users having the highest proportion of Ruminococcus and MMT patients having the highest abundance of Bifidobacterium and Lactobacillus. Conclusion: Drug use, cessation method, and diet contribute to shaping human gut communities. High beta diversity among MMT patients is likely driven by methadone use and high nutrient intake, leading to increased orexin A and enrichment for beneficial bacteria, while diversity in CD participants is largely influenced by diet.

HIV, Sexual Orientation, and Gut Microbiome Interactions

Recent studies have raised interest in the possibility that dysbiosis of the gut microbiome (i.e., the communities of bacteria residing in the intestine) in HIV-infected patients could contribute to chronic immune activation, and, thus, to elevated mortality and increased risk of inflammation-related clinical diseases (e.g., stroke, cardiovascular disease, cancer, long-bone fractures, and renal dysfunction) found even in those on effective antiretroviral therapy. Yet, to date, a consistent pattern of HIV-associated dysbiosis has not been identified. What is becoming clear, however, is that status as a man who has sex with men (MSM) may profoundly impact the structure of the gut microbiota, and that this factor likely confounded many HIV-related intestinal microbiome studies. However, what factor associated with MSM status drives these gut microbiota-related changes is unclear, and what impact, if any, these changes may have on the health of MSM is unknown. In this review, we outline available data on changes in the structure of the gut microbiome in HIV, based on studies that controlled for MSM status. We then examine what is known regarding the gut microbiota in MSM, and consider possible implications for research and the health of this population. Lastly, we discuss knowledge gaps and needed future studies.

The Impact of Human Immunodeficiency Virus Infection on Gut Microbiota α-Diversity: An Individual-level Meta-analysis

BACKGROUND

Whether human immunodeficiency virus (HIV) infection impacts gut microbial α-diversity is controversial. We reanalyzed raw 16S ribosomal RNA (rRNA) gene sequences and metadata from published studies to examine α-diversity measures between HIV-uninfected (HIV-) and HIV-infected (HIV+) individuals.

METHODS

We conducted a systematic review and individual level meta-analysis by searching Embase, Medline, and Scopus for original research studies (inception to 31 December 2017). Included studies reported 16S rRNA gene sequences of fecal samples from HIV+ patients. Raw sequence reads and metadata were obtained from public databases or from study authors. Raw reads were processed through standardized pipelines with use of a high-resolution taxonomic classifier. The χ2 test, paired t tests, and generalized linear mixed models were used to relate α-diversity measures and clinical metadata.

RESULTS

Twenty-two studies were identified with 17 datasets available for analysis, yielding 1032 samples (311 HIV-, 721 HIV+). HIV status was associated with a decrease in measures of α-diversity (P < .001). However, in stratified analysis, HIV status was associated with decreased α-diversity only in women and in men who have sex with women (MSW) but not in men who have sex with men (MSM). In analyses limited to women and MSW, controlling for HIV status, women displayed increased α-diversity compared with MSW.

CONCLUSIONS

Our study suggests that HIV status, sexual risk category, and gender impact gut microbial community α-diversity. Future studies should consider MSM status in gut microbiome analyses.

Alterations to the Gastrointestinal Microbiome Associated with Methamphetamine Use among Young Men who have Sex with Men

Methamphetamine (MA) use is a major public health problem in the United States, especially among people living with HIV (PLWH). Many MA-induced neurotoxic effects are mediated by inflammation and gut microbiota may play a role in this process, yet the effects of MA on the microbiome have not been adequately explored. Therefore, we performed 16S rRNA gene sequencing on rectal swab samples from 381 men who have sex with men, 48% of whom were PLWH and 41% of whom used MA. We compared microbiome composition between MA users and non-users while testing for potential interactions with HIV and controlling for numerous confounders using inverse probability of treatment weighting. We found that MA use explained significant variation in overall composition (R² = 0.005, p = 0.008) and was associated with elevated Finegoldia, Parvimonas, Peptoniphilus, and Porphyromonas and reduced Butyricicoccus and Faecalibacterium, among others. Genera including Actinomyces and Streptobacillus interacted with HIV status, such that they were increased in HIV+ MA users. Finegoldia and Peptoniphilus increased with increasing frequency of MA use, among others. In summary, MA use was associated with a microbial imbalance favoring pro-inflammatory bacteria, including some with neuroactive potential and others that have previously been associated with poor HIV outcomes.

Cocaine Induces Inflammatory Gut Milieu by Compromising the Mucosal Barrier Integrity and Altering the Gut Microbiota Colonization

Cocaine use disorder (CUD), a major health crisis, has traditionally been considered a complication of the CNS; however, it is also closely associated with malnourishment and deteriorating gut health. In light of emerging studies on the potential role of gut microbiota in neurological disorders, we sought to understand the causal association between CUD and gut dysbiosis. Using a comprehensive approach, we confirmed that cocaine administration in mice resulted in alterations of the gut microbiota. Furthermore, cocaine-mediated gut dysbiosis was associated with upregulation of proinflammatory mediators including NF-κB and IL-1β. In vivo and in vitro analyses confirmed that cocaine altered gut-barrier composition of the tight junction proteins while also impairing epithelial permeability by potentially involving the MAPK/ERK1/2 signaling. Taken together, our findings unravel a causal link between CUD, gut-barrier dysfunction and dysbiosis and set a stage for future development of supplemental strategies for the management of CUD-associated gut complications.

Neuroimmune mechanisms of psychostimulant and opioid use disorders

Substance use disorders are global health problems with few effective treatment options. Unfortunately, most potential pharmacological treatments are hindered by abuse potential of their own, limited efficacy, or adverse side effects. As a consequence, there is a pressing need for the development of addiction treatments with limited abuse potential and fewer off target effects. Given the difficulties in developing new pharmacotherapies for substance use disorders, there has been growing interest in medications that act on non-traditional targets. Recent evidence suggests a role for dysregulated immune signaling in the pathophysiology of multiple psychiatric diseases. While there is evidence that immune responses in the periphery and the central nervous system are altered by exposure to drugs of abuse, the contributions of neuroimmune interactions to addictive behaviors are just beginning to be appreciated. In this review, we discuss the data on immunological changes seen in clinical populations with substance use disorders, as well as in translational animal models of addiction. Importantly, we highlight those mechanistic findings showing causal roles for central or peripheral immune mediators in substance use disorder and appropriate animal models. Based on the literature reviewed here, it is clear that brain-immune system interactions in substance use disorders are much more complex and important than previously understood. While much work remains to be done, there are tremendous potential therapeutic implications for immunomodulatory treatments in substance use disorders.

Total and Differential White Blood Cell Counts, Cocaine, and Marijuana Use in Patients With Schizophrenia

Schizophrenia is associated with blood inflammatory marker abnormalities. Illicit drug use, which is common in schizophrenia, may modulate inflammatory marker levels. We examined effects of marijuana and cocaine use on white blood cell (WBC) counts in acutely ill, hospitalized patients with schizophrenia using a within-subjects and between-groups design. Mean total and differential WBC counts were first compared in acutely ill patients with schizophrenia for hospitalizations with and without either marijuana (n = 18) or cocaine (n = 24) use. Mean total and differential WBC counts were then compared between patients with schizophrenia with either marijuana or cocaine use and patients with a negative urine drug screen (UDS; n = 43). Patients with schizophrenia had significantly higher total WBC, lymphocytes, and monocytes during hospitalizations with (vs. without) cocaine use. Patients with cocaine use also had significantly higher monocytes and eosinophils than those with a negative UDS. Our findings suggest that substance use, particularly of cocaine, may modulate inflammatory marker levels in acutely ill, hospitalized patients with schizophrenia.

A potential role for the gut microbiome in substance use disorders

Pathological substance use disorders represent a major public health crisis with limited effective treatment options. While much work has been done to understand the neuronal signaling networks and intracellular signaling cascades associated with prolonged drug use, these studies have yielded few successful treatment options for substance use disorders. In recent years, there has been a growing interest to explore interactions between the peripheral immune system, the gut microbiome, and the CNS. In this review, we will present a summary of existing evidence, suggesting a potential role for gut dysbiosis in the pathogenesis of substance use disorders. Clinical evidence of gut dysbiosis in human subjects with substance use disorder and preclinical evidence of gut dysbiosis in animal models of drug addiction are discussed in detail. Additionally, we examine how changes in the gut microbiome and its metabolites may not only be a consequence of substance use disorders but may in fact play a role in mediating behavioral response to drugs of abuse. While much work still needs to be done, understanding the interplay of gut microbiome in substance use disorders may offer a promising avenue for future therapeutic development.

Do your gut microbes affect your brain dopamine?

Increasing evidence shows changes in gut microbiota composition in association with psychiatric disorders, including anxiety and depression. Moreover, it has been reported that perturbations in gut microbe diversity and richness influence serotonergic, GABAergic, noradrenergic, and dopaminergic neurotransmission. Among these, dopamine is regarded as a main regulator of cognitive functions such as decision making, attention, memory, motivation, and reward. In this work, we will highlight findings that link alterations in intestinal microbiota and dopaminergic neurotransmission, with a particular emphasis on the mesocorticolimbic circuit, which is involved in reward to natural reinforcers, as well as abuse substances. For this, we reviewed evidence from studies carried out on germ-free animals, or in rodents subjected to intestinal dysbiosis using antibiotics, and also through the use of probiotics. All this evidence strongly supports that the microbiota-gut-brain axis is key to the physiopathology of several neuropsychiatric disorders involving those where dopaminergic neurotransmission is compromised. In addition, the gut microbiota appears as a key player when it comes to proposing novel strategies to the treatment of these psychiatric conditions.

Psychotropics and the Microbiome: a Chamber of Secrets…

The human gut contains trillions of symbiotic bacteria that play a key role in programming different aspects of host physiology in health and disease. Psychotropic medications act on the central nervous system (CNS) and are used in the treatment of various psychiatric disorders. There is increasing emphasis on the bidirectional interaction between drugs and the gut microbiome. An expanding body of evidence supports the notion that microbes can metabolise drugs and vice versa drugs can modify the gut microbiota composition. In this review, we will first give a comprehensive introduction about this bidirectional interaction, then we will take into consideration different classes of psychotropics including antipsychotics, antidepressants, antianxiety drugs, anticonvulsants/mood stabilisers, opioid analgesics, drugs of abuse, alcohol, nicotine and xanthines. The varying effects of these widely used medications on microorganisms are becoming apparent from in vivo and in vitro studies. This has important implications for the future of psychopharmacology pipelines that will routinely need to consider the host microbiome during drug discovery and development.

Effects of HIV viremia on the gastrointestinal microbiome of young MSM

OBJECTIVE

We employed a high-dimensional covariate adjustment method in microbiome analysis to better control for behavioural and clinical confounders, and in doing so examine the effects of HIV on the rectal microbiome.

DESIGN

Three hundred and eighty-three MSM were grouped into four HIV viremia categories: HIV negative (n = 200), HIV-positive undetectable (HIV RNA < 20 copies/ml; n = 66), HIV-positive suppressed (RNA 20-200 copies/ml; n = 72) and HIV-positive viremic (RNA > 200 copies/ml; n = 45).

METHODS

We performed 16S rRNA gene sequencing on rectal swab samples and used inverse probability of treatment-weighted marginal structural models to examine differences in microbial composition by HIV viremia category.

RESULTS

HIV viremia explained a significant amount of variability in microbial composition in both unadjusted and covariate-adjusted analyses (R = 0.011, P = 0.02). Alterations in bacterial taxa were more apparent with increasing viremia. Relative to the HIV-negative group, HIV-positive undetectable participants showed depletions in Brachyspira, Campylobacter and Parasutterella, while suppressed participants demonstrated depletions in Barnesiella, Brachyspira and Helicobacter. The microbial signature of viremic men was most distinct, showing enrichment in inflammatory genera Peptoniphilus, Porphyromonas and Prevotella and depletion of Bacteroides, Brachyspira and Faecalibacterium, among others.

CONCLUSION

Our study shows that, after accounting for the influence of multiple confounding factors, HIV is associated with dysbiosis in the gastrointestinal microbiome in a dose-dependent manner. This analytic approach may allow for better identification of true microbial associations by limiting the effects of confounding, and thus improve comparability across future studies.

Alcohol, liver disease and the gut microbiota

Alcoholic liver disease, which ranges from mild disease to alcoholic hepatitis and cirrhosis, is a leading cause of morbidity and mortality worldwide. Alcohol intake can lead to changes in gut microbiota composition, even before liver disease development. These alterations worsen with advancing disease and could be complicit in disease progression. Microbial function, especially related to bile acid metabolism, can modulate alcohol-associated injury even in the presence of cirrhosis and alcoholic hepatitis. Microbiota changes might also alter brain function, and the gut-brain axis might be a potential target to reduce alcoholic relapse risk. Gut microbiota manipulation including probiotics, faecal microbial transplant and antibiotics has been studied in alcoholic liver disease with varying success. Further investigation of the modulation of the gut-liver axis is relevant, as most of these patients are not candidates for liver transplantation. This Review focuses on clinical studies involving the gut microbiota in patients with alcoholic liver disease across the spectrum from alcoholic fatty liver to cirrhosis and alcoholic hepatitis. Specific alterations in the gut-liver-brain axis that are complicit in the interactions between the gut microbiota and alcohol addiction are also reviewed.

Among older adults, age-related changes in the stool microbiome differ by HIV-1 serostatus

Background

HIV-1 infection and physiological aging are independently linked to elevated systemic inflammation and changes in enteric microbial communities (dysbiosis). However, knowledge of the direct effect of HIV infection on the aging microbiome and potential links to systemic inflammation is lacking.

Methods

In a cross-sectional study of older people living with HIV (PLWH) (median age 61.5 years, N = 14) and uninfected controls (median 58 years, n = 22) we compared stool microbiota, levels of microbial metabolites (short-chain fatty acid levels, SCFA) and systemic inflammatory biomarkers by HIV serostatus and age.

Findings

HIV and age were independently associated with distinct changes in the stool microbiome. For example, abundances of Enterobacter and Paraprevotella were higher and Eggerthella and Roseburia lower among PLWH compared to uninfected controls. Age-related microbiome changes also differed by HIV serostatus. Some bacteria with inflammatory potential (e.g. Escherichia) increased with age among PLWH, but not controls. Stool SCFA levels were similar between the two groups yet patterns of associations between individual microbial taxa and SCFA levels differed. Abundance of various genera including Escherichia and Bifidobacterium positively associated with inflammatory biomarkers (e.g. soluble Tumor Necrosis Factor Receptors) among PLWH, but not among controls.

Interpretation

The age effect on the gut microbiome and associations between microbiota and microbial metabolites or systemic inflammation differed based on HIV serostatus, raising important implications for the impact of therapeutic interventions, dependent on HIV serostatus or age.

Altered Gut Microbiota in Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune-mediated disorder, the etiology of which involves both environmental factors and genetics. While the exact factors responsible for predisposition to MG remain elusive, it is hypothesized that gut microbiota play a critical role in the pathogenesis of MG. This study investigated whether gut microbiota are altered in MG patients by comparing the fecal microbiota profiles of MG patients to those of age- and sex-matched healthy controls. Phylotype profiles of gut microbial populations were generated using hypervariable tag sequencing of the V4 region of the 16S ribosomal RNA gene. Fecal short-chain fatty acids (SCFAs) were assessed by gas chromatographic analyses. The results demonstrated that, compared to the healthy cohort, the gut microbiota of the MG group was changed in terms of the relative abundances of bacterial taxa, with sharply reduced microbial richness, particularly in the genus Clostridium. The fecal SCFA content was significantly lower in the MG group. Furthermore, microbial dysbiosis was closely related to the levels of inflammatory biomarkers in the sera of MG patients.

An exploration of Prevotella-rich microbiomes in HIV and men who have sex with men

BACKGROUND

Gut microbiome characteristics associated with HIV infection are of intense research interest but a deep understanding has been challenged by confounding factors across studied populations. Notably, a Prevotella-rich microbiome described in HIV-infected populations is now understood to be common in men who have sex with men (MSM) regardless of HIV status, but driving factors and potential health implications are unknown.

RESULTS

Here, we further define the MSM-associated gut microbiome and describe compositional differences between the fecal microbiomes of Prevotella-rich MSM and non-MSM that may underlie observed pro-inflammatory properties. Furthermore, we show relatively subtle gut microbiome changes in HIV infection in MSM and women that include an increase in potential pathogens that is ameliorated with antiretroviral therapy (ART). Lastly, using a longitudinal cohort, we describe microbiome changes that happen after ART initiation.

CONCLUSIONS

This study provides an in-depth characterization of microbiome differences that occur in a US population infected with HIV and demonstrates the degree to which these differences may be driven by lifestyle factors, ART, and HIV infection itself. Understanding microbiome compositions that occur with sexual behaviors that are high risk for acquiring HIV and untreated and ART-treated HIV infection will guide the investigation of immune and metabolic functional implications to ultimately target the microbiome therapeutically.

Defining Dysbiosis in Disorders of Movement and Motivation

The gut microbiota has emerged as a critical player in shaping and modulating brain function and has been shown to influence numerous behaviors, including anxiety and depression-like behaviors, sociability, and cognition. However, the effects of the gut microbiota on specific disorders associated with thalamo-cortico-basal ganglia circuits, ranging from compulsive behavior and addiction to altered sensation and motor output, are only recently being explored. Wholesale depletion and alteration of gut microbial communities in rodent models of disorders, such as Parkinson's disease, autism, and addiction, robustly affect movement and motivated behavior. A new frontier therefore lies in identifying specific microbial alterations that affect these behaviors and understanding the underlying mechanisms of action. Comparing alterations in gut microbiota across multiple basal-ganglia associated disease states allows for identification of common mechanistic pathways that may interact with distinct environmental and genetic risk factors to produce disease-specific outcomes.

Effects of Substance Use and Sex Practices on the Intestinal Microbiome During HIV-1 Infection

Background

Human immunodeficiency virus type 1 (HIV-1) infection alters the human intestinal microbiome; however, behavioral factors driving these changes remain poorly defined. Here we examine the effects of substance use and sex behavior on the microbiome during HIV-1 infection.

Methods

Archival rectal swab specimens, urine drug test results, and responses to substance use and sex behavior questionnaires were obtained from 37 HIV-positive participants at 2 time points, separated by 6 months, in a cohort examining the effects of substance use in men who have sex with men (MSM). Microbiome profiling was performed using 16S ribosomal RNA gene sequencing, and associations with behavioral factors were examined using 0-inflated negative binomial regression. Further analysis of selected variables of interest was performed using propensity scores to account for multiple confounders.

Results

Using permutational multivariate analysis of variance, we found that receptive anal intercourse, methamphetamine use, and marijuana use were among the most important drivers of microbiome variation. Propensity score-adjusted analyses revealed that methamphetamine use and marijuana use displayed unique associations; methamphetamine use was associated with an increased abundance of Porphyromonas and Granulicatella organisms and a decreased abundance of Ruminococcus, Collinsella, and Parabacteroides organisms, whereas marijuana use was associated with an increased abundance of Ruminococcus, Clostridium cluster IV, Solobacterium, and Fusobacterium organisms and a decreased abundance of Acidaminococcus, Prevotella, Dialister, Anaerostipes, and Dorea organisms.

Conclusions

Drug use and sex behavior are important factors associated with intestinal dysbiosis during chronic HIV-1 infection among young MSM.

The Neuroendocrinology of the Microbiota-Gut-Brain Axis: A Behavioural Perspective

The human gut harbours trillions of symbiotic bacteria that play a key role in programming different aspects of host physiology in health and disease. These intestinal microbes are also key components of the gut-brain axis, the bidirectional communication pathway between the gut and the central nervous system (CNS). In addition, the CNS is closely interconnected with the endocrine system to regulate many physiological processes. An expanding body of evidence is supporting the notion that gut microbiota modifications and/or manipulations may also play a crucial role in the manifestation of specific behavioural responses regulated by neuroendocrine pathways. In this review, we will focus on how the intestinal microorganisms interact with elements of the host neuroendocrine system to modify behaviours relevant to stress, eating behaviour, sexual behaviour, social behaviour, cognition and addiction.

Reduced microbiome alpha diversity in young patients with ADHD

ADHD is a psychiatric disorder which is characterized by hyperactivity, impulsivity and attention problems. Due to recent findings of microbial involvement in other psychiatric disorders like autism and depression, a role of the gut microbiota in ADHD pathogenesis is assumed but has not yet been investigated. In this study, the gut microbiota of 14 male ADHD patients (mean age: 11.9 yrs.) and 17 male controls (mean age: 13.1 yrs.) was examined via next generation sequencing of 16S rDNA and analyzed for diversity and biomarkers. We found that the microbial diversity (alpha diversity) was significantly decreased in ADHD patients compared to controls (pShannon = 0.036) and that the composition (beta diversity) differed significantly between patients and controls (pANOSIM = 0.033, pADONIS = 0.006, pbetadisper = 0.002). In detail, the bacterial family Prevotellacae was associated with controls, while patients with ADHD showed elevated levels of Bacteroidaceae, and both Neisseriaceae and Neisseria spec. were found as possible biomarkers for juvenile ADHD. Our results point to a possible link of certain microbiota with ADHD, with Neisseria spec. being a very promising ADHD-associated candidate. This finding provides the basis for a systematic, longitudinal assessment of the role of the gut microbiome in ADHD, yielding promising potential for both prevention and therapeutic intervention.

HIV and aging: role of the microbiome

PURPOSE OF REVIEW

The purpose of this article is to review age-associated alterations in microbiota composition, diversity and functional features in context of immune senescence, chronic inflammation and comorbidities associated with HIV infection. The overall goal is to assess whether modulating the microbiome will likely improve resilience of the immune system and augment return to health.

RECENT FINDINGS

Alteration in the gut microbiota composition diversity and function occur in HIV and aging. Importantly, butyrate producing bacteria are reduced in both HIV and aging individuals. There is increasing relevance of studying metabolomics in the context of HIV-associated non-AIDS comorbidities and aging. Interventional prospects of probiotics, prebiotics and fecal microbiota transplantation in HIV and aging will provide novel therapeutic approaches.

SUMMARY

Increasing evidence suggests a significant link in changes in the composition, diversity and functional aspects of intestinal microbiome with normal aging and HIV infection. Data on association of metabolites produced by the microbiome with HIV-associated non-AIDS comorbidities is mounting. The impact of the microbiome alterations on inflammation, immune and organ senescence and mechanisms by which bio-behavioral pathways will exacerbate these outcomes needs to be further evaluated.

The Microbiota, the Gut and the Brain in Eating and Alcohol Use Disorders: A 'Ménage à Trois'?

Aims

Accumulating evidence for the influence of the gut microbiota on the bidirectional communication along the gut-brain axis suggests a role of the gut microbiota in eating disorders (EDs) and alcohol and substance use disorders. The potential influence of altered gut microbiota (dysbiosis) on behaviors associated with such disorders may have implications for developing therapeutic interventions.

Methods

A systematic review of preclinical and clinical studies evaluating the gut microbiota, EDs and alcohol and substance use disorders was conducted using MEDLINE, Embase and Web of Science databases with the objective being to examine the role of the gut microbiota in behavioral correlates of these disorders. Original papers focused on the gut microbiota and potential behavioral implications were deemed eligible for consideration.

Results

The resulting 12 publications were limited to gut microbiota studies related to EDs and alcohol and substance use disorders. Some studies suggest that dysbiosis and gut microbial byproducts may influence the pathophysiology of EDs via direct and indirect interference with peptide hormone signaling. Additionally, dysbiosis was shown to be correlated with alcohol use disorder-related symptoms, i.e. craving, depression and anxiety. Finally, a mouse study suggests that manipulations in the gut microbiota may affect cocaine-related behaviors.

Conclusions

Promising, albeit preliminary, findings suggest a potential role of the gut microbiota in behavioral correlates of EDs and alcohol and substance use disorders.

Short summary

Preliminary evidence exists supporting the role of the gut microbiota in eating disorders and alcohol and substance use disorders, although additional investigation is needed to determine what is causative versus epiphenomenological.

Independent associations and effect modification between lifetime substance use and recent mood disorder diagnosis with household food insecurity

Poor mental health and substance use are associated with food insecurity, however, their potential combined effects have not been studied. This study explored independent associations and effect modification between lifetime substance use and mood disorder in relation to food insecurity. Poisson regression analysis of data from British Columbia respondents (n = 13,450; 12 years+) in the 2007/08 Canadian Community Health Survey was conducted. Measures included The Household Food Security Survey Module (7.3% food insecure), recent diagnosis of a mood disorder (self-reported; 9.5%), lifetime use of cannabis, cocaine/crack, ecstasy, hallucinogens, and speed, any lifetime substance use, sociodemographic covariates, and the interaction terms of mood disorder by substance. For those with recent diagnosis of a mood disorder the prevalence of lifetime substance use ranged between 1.2 to 5.7% and were significantly higher than those without recent mood disorder diagnosis or lifetime use of substances (p’s < 0.05). For respondents with a recent mood disorder diagnosis or who used cannabis, food insecurity prevalence was higher compared to the general sample (p < 0.001); prevalence was lower for cocaine/crack use (p < 0.05). Significant effect modification was found between mood disorder with cannabis, ecstasy, hallucinogen and any substance use over the lifetime (PRs 0.51 to 0.64, p’s 0.022 to 0.001). Independent associations were found for cocaine/crack and speed use (PRs 1.68, p’s < 0.001) and mood disorder (PRs 2.02, p’s < 0.001). Based on these findings and the existing literature, future study about coping and resilience in the context of substance use, mental health, and food insecurity may lead to the development of relevant interventions aimed at mental well-being and food security.

Cigarette smoking is associated with an altered vaginal tract metabolomic profile

Cigarette smoking has been associated with both the diagnosis of bacterial vaginosis (BV) and a vaginal microbiota lacking protective Lactobacillus spp. As the mechanism linking smoking with vaginal microbiota and BV is unclear, we sought to compare the vaginal metabolomes of smokers and non-smokers (17 smokers/19 non-smokers). Metabolomic profiles were determined by gas and liquid chromatography mass spectrometry in a cross-sectional study. Analysis of the 16S rRNA gene populations revealed samples clustered into three community state types (CSTs) ---- CST-I (L. crispatus-dominated), CST-III (L. iners-dominated) or CST-IV (low-Lactobacillus). We identified 607 metabolites, including 12 that differed significantly (q-value < 0.05) between smokers and non-smokers. Nicotine, and the breakdown metabolites cotinine and hydroxycotinine were substantially higher in smokers, as expected. Among women categorized to CST-IV, biogenic amines, including agmatine, cadaverine, putrescine, tryptamine and tyramine were substantially higher in smokers, while dipeptides were lower in smokers. These biogenic amines are known to affect the virulence of infective pathogens and contribute to vaginal malodor. Our data suggest that cigarette smoking is associated with differences in important vaginal metabolites, and women who smoke, and particularly women who are also depauperate for Lactobacillus spp., may have increased susceptibilities to urogenital infections and increased malodor.

Sex Differences in Select Non-communicable HIV-Associated Comorbidities: Exploring the Role of Systemic Immune Activation/Inflammation

PURPOSE OF THE REVIEW

The goals of this review are to (1) explore HIV-associated cardiovascular disease (CVD), neurocognitive impairment, and non-AIDS-defining cancers (NADC) as heterogeneous model disease states fuelled in part by systemic immune activation/inflammation; (2) consider sex differences in the epidemiology of these diseases in both high-resource and lower-resource settings; and (3) examine biological and environmental factors which may contribute to heightened systemic immune activation/inflammation specifically among women living with HIV (WLHIV).

RECENT FINDINGS

The observation that WLHIV have higher levels of systemic immune activation/inflammation than men living with HIV (MLHIV) may be relevant to sex differences in select non-communicable HIV-associated comorbidities. Heightened systemic immune activation among WLHIV may be influenced by sex-specific responses to the virus and to immunomodulatory agents, as well as by behavioral choices/comorbid conditions and perturbations in the hypothalamic-pituitary-gonadal axis. Additional research is needed to elucidate region-specific drivers of heightened systemic immune activation/inflammation among WLHIV and to determine whether WLHIV who present with one immune-mediated HIV-associated comorbidity (e.g., cognitive impairment) may be at increased risk for another (e.g., CVD, NADC). This kind of research would facilitate improved risk prediction for non-communicable HIV-associated comorbidities among WLHIV and the development of targeted immunomodulatory prevention strategies.

Gut Microbiota Analysis in Rats with Methamphetamine-Induced Conditioned Place Preference

Methamphetamine abuse is a major public health crisis. Because accumulating evidence supports the hypothesis that the gut microbiota plays an important role in central nervous system (CNS) function, and research on the roles of the microbiome in CNS disorders holds conceivable promise for developing novel therapeutic avenues for treating CNS disorders, we sought to determine whether administration of methamphetamine leads to alterations in the intestinal microbiota. In this study, the gut microbiota profiles of rats with methamphetamine-induced conditioned place preference (CPP) were analyzed through 16S rRNA gene sequencing. The fecal microbial diversity was slightly higher in the METH CPP group. The propionate-producing genus Phascolarctobacterium was attenuated in the METH CPP group, and the family Ruminococcaceae was elevated in the METH CPP group. Short chain fatty acid analysis revealed that the concentrations of propionate were decreased in the fecal matter of METH-administered rats. These findings provide direct evidence that administration of METH causes gut dysbiosis, enable a better understanding of the function of gut microbiota in the process of drug abuse, and provide a new paradigm for addiction treatment.

Bacterial Diversity of Intestinal Microbiota in Patients with Substance Use Disorders Revealed by 16S rRNA Gene Deep Sequencing

Substance abuse and addiction are worldwide concerns. In China, populated with over 1.3 billion people, emerging studies show a steady increase in substance abuse and substance-related problems. Some of the major challenges include a lack of an effective evaluation platform to determine the health status of substance-addicted subjects. It is known that the intestinal microbiota is associated to the occurrence and development of human diseases. However, the changes of bacterial diversity of intestinal microbiota in substance-addicted subjects have not been clearly characterized. Herein, we examined the composition and diversity of intestinal microbiota in 45 patients with substance use disorders (SUDs) and in 48 healthy controls (HCs). The results show that the observed species diversity index and the abundance of Thauera, Paracoccus, and Prevotella are significantly higher in SUDs compared to HCs. The functional diversity of the putative metagenomes analysis reveals that pathways including translation, DNA replication and repair, and cell growth and death are over-represented while cellular processes and signaling, and metabolism are under-represented in SUDs. Overall, the analyses show that there seem to be changes in the microbiota that are associated with substance use across an array of SUDs, providing fundamental knowledge for future research in substance-addiction assessment tests.

Immune activation and neuroinflammation in alcohol use and HIV infection: evidence for shared mechanisms

BACKGROUND

Emerging research points to innate immune mechanisms in the neuropathological and behavioral consequences of heavy alcohol use. Alcohol use is common among people living with HIV infection (PLWH), a chronic condition that carries its own set of long-term effects on brain and behavior. Notably, neurobiological and cognitive profiles associated with heavy alcohol use and HIV infection share several prominent features. This observation raises questions about interacting biological mechanisms as well as compounded impairment when HIV infection and heavy drinking co-occur.

OBJECTIVE AND METHOD

This narrative overview discusses peer-reviewed research on specific immune mechanisms of alcohol that exhibit apparent potential to compound the neurobiological and psychiatric sequelae of HIV infection. These include microbial translocation, systemic immune activation, blood-brain barrier compromise, microglial activation, and neuroinflammation.

RESULTS

Clinical and preclinical evidence supports overlapping mechanistic actions of HIV and alcohol use on peripheral and neural immune systems. In preclinical studies, innate immune signaling mediates many of the detrimental neurocognitive and behavioral effects of alcohol use. Neuropsychopharmacological research suggests potential for a feed-forward cycle in which heavy drinking induces innate immune signaling, which in turn stimulates subsequent alcohol use behavior.

CONCLUSION

Alcohol-induced immune activation and neuroinflammation are a serious health concern for PLWH. Future research to investigate specific immune effects of alcohol in the context of HIV infection has potential to identify novel targets for therapeutic intervention.

Towards an Immunophenotype of Schizophrenia: Progress, Potential Mechanisms, and Future Directions

The evidence to date, coupled with advances in immunology and genetics has afforded the field an unparalleled opportunity to investigate the hypothesis that a subset of patients with schizophrenia may manifest an immunophenotype, toward new potential diagnostics and therapeutics to reduce risk, alleviate symptoms, and improve quality of life in both at-risk populations and patients with established schizophrenia. In this paper, we will first summarize the findings on immune dysfunction in schizophrenia, including (1) genetic, prenatal, and premorbid immune risk factors and (2) immune markers across the clinical course of the disorder, including cytokines; C-reactive protein; immune cells; antibodies, autoantibodies and comorbid autoimmune disorders; complement; oxidative stress; imaging of neuroinflammation; infections; and clinical trials of anti-inflammatory agents and immunotherapy. We will then discuss a potential mechanistic framework toward increased understanding of a potential schizophrenia immunophenotype. We will then critically appraise the existing literature, and discuss suggestions for the future research agenda in this area that are needed to rigorously evaluate this hypothesis.

The gut microbiome and HIV-1 pathogenesis: a two-way street

HIV-1 infection is associated with substantial damage to the gastrointestinal tract resulting in structural impairment of the epithelial barrier and a disruption of intestinal homeostasis. The accompanying translocation of microbial products and potentially microbes themselves from the lumen into systemic circulation has been linked to immune activation, inflammation, and HIV-1 disease progression. The importance of microbial translocation in the setting of HIV-1 infection has led to a recent focus on understanding how the communities of microbes that make up the intestinal microbiome are altered during HIV-1 infection and how they interact with mucosal immune cells to contribute to inflammation. This review details the dysbiotic intestinal communities associated with HIV-1 infection and their potential link to HIV-1 pathogenesis. We detail studies that begin to address the mechanisms driving microbiota-associated immune activation and inflammation and the various treatment strategies aimed at correcting dysbiosis and improving the overall health of HIV-1-infected individuals. Finally, we discuss how this relatively new field of research can advance to provide a more comprehensive understanding of the contribution of the gut microbiome to HIV-1 pathogenesis.

Alterations of the Host Microbiome Affect Behavioral Responses to Cocaine

Addiction to cocaine and other psychostimulants represents a major public health crisis. The development and persistence of addictive behaviors comes from a complex interaction of genes and environment - the precise mechanisms of which remain elusive. In recent years a surge of evidence has suggested that the gut microbiome can have tremendous impact on behavioral via the microbiota-gut-brain axis. In this study we characterized the influence of the gut microbiota on cocaine-mediated behaviors. Groups of mice were treated with a prolonged course of non-absorbable antibiotics via the drinking water, which resulted in a substantial reduction of gut bacteria. Animals with reduced gut bacteria showed an enhanced sensitivity to cocaine reward and enhanced sensitivity to the locomotor-sensitizing effects of repeated cocaine administration. These behavioral changes were correlated with adaptations in multiple transcripts encoding important synaptic proteins in the brain’s reward circuitry. This study represents the first evidence that alterations in the gut microbiota affect behavioral response to drugs of abuse.

Fecal bacterial microbiome diversity in chronic HIV-infected patients in China

The purpose of this study was to identify fecal bacterial microbiome changes in patients with chronic human immunodeficiency virus (HIV) infection in China. Bacterial 16S rRNA genes were amplified, sequenced (454 pyrosequencing), and clustered into operational taxonomic units using the QIIME software. Relative abundance at the phylum and genus levels were calculated. Alpha diversity was determined by Chao 1 and observed-species indices, and beta diversity was determined by double principal component analysis using the estimated phylogeny-based unweighted Unifrac distance matrices. Fecal samples of the patients with chronic HIV-infection tended to be enriched with bacteria of the phyla Firmicutes (47.20%±0.43 relative abundance) and Proteobacteria (37.21%±0.36) compared with those of the non-HIV infected controls (17.95%±0.06 and 3.81%±0.02, respectively). Members of the genus Bilophila were exclusively detected in samples of the non-HIV infected controls. Bacteroides and arabacteroides were more abundant in the chronic HIV-infected patients. Our study indicated that chronic HIV-infected patients in China have a fecal bacterial microbiome composition that is largely different from that found in non-HIV infected controls, and further study is needed to evaluate whether microbiome changes play a role in disease complications in the distal gut, including opportunistic infections.

Correlation of the lung microbiota with metabolic profiles in bronchoalveolar lavage fluid in HIV infection

BACKGROUND

While 16S ribosomal RNA (rRNA) sequencing has been used to characterize the lung's bacterial microbiota in human immunodeficiency virus (HIV)-infected individuals, taxonomic studies provide limited information on bacterial function and impact on the host. Metabolic profiles can provide functional information on host-microbe interactions in the lungs. We investigated the relationship between the respiratory microbiota and metabolic profiles in the bronchoalveolar lavage fluid of HIV-infected and HIV-uninfected outpatients.

RESULTS

Targeted sequencing of the 16S rRNA gene was used to analyze the bacterial community structure and liquid chromatography-high-resolution mass spectrometry was used to detect features in bronchoalveolar lavage fluid. Global integration of all metabolic features with microbial species was done using sparse partial least squares regression. Thirty-nine HIV-infected subjects and 20 HIV-uninfected controls without acute respiratory symptoms were enrolled. Twelve mass-to-charge ratio (m/z) features from C18 analysis were significantly different between HIV-infected individuals and controls (false discovery rate (FDR) = 0.2); another 79 features were identified by network analysis. Further metabolite analysis demonstrated that four features were significantly overrepresented in the bronchoalveolar lavage (BAL) fluid of HIV-infected individuals compared to HIV-uninfected, including cystine, two complex carbohydrates, and 3,5-dibromo-L-tyrosine. There were 231 m/z features significantly associated with peripheral blood CD4 cell counts identified using sparse partial least squares regression (sPLS) at a variable importance on projection (VIP) threshold of 2. Twenty-five percent of these 91 m/z features were associated with various microbial species. Bacteria from families Caulobacteraceae, Staphylococcaceae, Nocardioidaceae, and genus Streptococcus were associated with the greatest number of features. Glycerophospholipid and lineolate pathways correlated with these bacteria.

CONCLUSIONS

In bronchoalveolar lavage fluid, specific metabolic profiles correlated with bacterial organisms known to play a role in the pathogenesis of pneumonia in HIV-infected individuals. These findings suggest that microbial communities and their interactions with the host may have functional metabolic impact in the lung.

HIV-induced immunosuppression is associated with colonization of the proximal gut by environmental bacteria

OBJECTIVES

To evaluate the impact of HIV infection on colonization resistance in the proximal gut.

DESIGN

It was a case-control study.

METHODS

We contrasted microbiota composition between eight HIV-1-infected patients and eight HIV-negative controls to characterize community alteration and detect exogenous bacteria in the esophagus, stomach, and duodenum, as well as the mouth using a universal 16s ribosomal RNA gene survey and correlated the findings with HIV serostatus and peripheral blood T-cell counts.

RESULTS

HIV infection was associated with an enrichment of Proteobacteria (P=0.020) and depletion of Firmicutes (P = 0.005) in the proximal gut. In particular, environmental species Burkholderia fungorum and Bradyrhizobium pachyrhizi colonized the duodenum of HIV patients who had abnormal blood CD4 T-cell counts but were absent in HIV-negative controls or HIV patients whose CD4 cell counts were normal. The two species coexisted and exhibited a decreasing trend proximally toward the stomach and esophagus and were virtually absent in the mouth. B. fungorum always outnumbered B. pachyrhizi in a ratio of approximately 15 to 1 regardless of the body sites (P < 0.0001, r = 0.965). Their abundance was inversely correlated with CD4 cell counts (P = 0.004) but not viral load. Overgrowth of potential opportunistic pathogens for example, Prevotella, Fusobacterium, and Ralstonia and depletion of beneficial bacteria, for example, Lactobacillus was also observed in HIV patients.

CONCLUSIONS

The colonization of the duodenum by environmental bacteria reflects loss of colonization resistance in HIV infection. Their correlation with CD4 cell counts suggests that compromised immunity could be responsible for the observed invasion by exogenous microbes.

The rectal microbiota of cats infected with feline immunodeficiency virus infection and uninfected controls

Rectal swabs were collected from 31 cats, 16 with FIV infection and 15 uninfected controls, to evaluate and compare the rectal bacterial microbiota in cats with feline immunodeficiency virus (FIV) infection and uninfected controls. The rectal microbiota was characterized via next generation sequencing of 16S rRNA gene (V4 region) polymerase chain reaction products. Eighteen different phyla were identified. Firmicutes dominated in both groups, followed by Proteobacteria and Actinobacteria, but there were no significant differences between groups. When predominant orders are compared, FIV-infected cats had significant higher median relative abundances of Bifidobacteriales (P=0.022), Lactobacillales (P=0.022) and Aeromonadales (P=0.043). No differences were identified in the 50 most common genera when adjusted for false discovery rate. There were significant differences in community membership (Jaccard index, unifrac P=0.008, AMOVA P<0.001) and community structure (Yue&Clayton index, unifrac P=0.03, AMOVA P=0.005) between groups. However, only one metacommunity (enterotype) was identified. The rectal microbiota differed between cats with FIV infection and uninfected controls. Some of the changes that were noted have been associated with 'dysbiosis' and proinflammatory states in other species, so it is possible that subclinical alteration in the intestinal microbiota could influence the health of FIV-infected cats. Evaluation of the reasons for microbiota alteration and the potential impact on cat health is required.

Intestinal microbiota, microbial translocation, and systemic inflammation in chronic HIV infection

BACKGROUND

Despite effective antiretroviral therapy (ART), patients with chronic human immunodeficiency virus (HIV) infection have increased microbial translocation and systemic inflammation. Alterations in the intestinal microbiota may play a role in microbial translocation and inflammation.

METHODS

We profiled the fecal microbiota by pyrosequencing the gene encoding 16S ribosomal RNA (rRNA) and measured markers of microbial translocation and systemic inflammation in 21 patients who had chronic HIV infection and were receiving suppressive ART (cases) and 16 HIV-uninfected controls.

RESULTS

The fecal microbial community composition was significantly different between cases and controls. The relative abundance of Proteobacteria, Gammaproteobacteria, Enterobacteriales, Enterobacteriaceae, Erysipelotrichi, Erysipelotrichales, Erysipelotrichaceae, and Barnesiella was significantly enriched in cases, whereas that of Rikenellaceae and Alistipes was depleted. The plasma soluble CD14 level (sCD14) was significantly higher and the endotoxin core immunoglobulin M (IgM) level lower in cases, compared with controls. There were significant positive correlations between the relative abundances of Enterobacteriales and Enterobacteriaceae and the sCD14 level; the relative abundances of Gammaproteobacteria, Enterobacteriales, and Enterobacteriaceae and the interleukin 1β (IL-1β) level; the relative abundances of Enterobacteriales and Enterobacteriaceae and the interferon γ level; and the relative abundances of Erysipelotrichi and Barnesiella and the TNF-α level. There were negative correlations between endotoxin core IgM and IL-1β levels.

CONCLUSIONS

Patients who have chronic HIV infection and are receiving suppressive ART display intestinal dysbiosis associated with increased microbial translocation and significant associations between specific taxa and markers of microbial translocation and systemic inflammation. This was an exploratory study, the findings of which need to be confirmed.