HIV enteropathy and aging: gastrointestinal immunity, mucosal epithelial barrier, and microbial translocation. Curr Opin HIV AIDS. 2014;9:309-316. [PMID: 24871087 DOI: 10.1097/coh.0000000000000066]

Effect of intake of probiotics and probiotic fermented foods on clinical outcomes among people living with HIV: A systematic review and meta-analysis

OBJECTIVE

The objective of the study was to determine the effect of probiotics and of probiotic-fermented foods on CD4 T-cell count, viral load, anaemia and body mass index (BMI) among people living with HIV (PLHIV).

METHODS

In this article, we systematically reviewed the evidence on the influence of probiotic supplementation on CD4 lymphocyte count, viral load and anaemia among PLHIV on highly active antiretroviral therapy (HAART) and those who were HAART-naive. Medical literature databases identified randomised trials and pre-post studies of probiotic supplementation and HIV-related outcomes, and random effects meta-analysis was conducted.

RESULTS

The preponderance of the evidence suggests that probiotic supplementation only improved CD4 lymphocyte count modestly, with quantitatively greater impact among individuals who were HAART-naive compared to HAART-experienced individuals. Probiotic supplementation improved CD4 lymphocyte count by 53 cells/mm3 (95% CI: 22 to 85) from 18 studies. Probiotic supplementation however reduced haemoglobin concentration by -2.1 g/L (95% CI: -4.0 to -0.2). Although viral load remain unchanged in HAART-experienced participants following probiotic supplementation, HAART-naïve participants saw a decrease in viral load. There were too few studies on the impact of probiotic supplementation on viral load (N = 1).

CONCLUSION

Probiotic supplementation resulted in a modest increase in CD4 lymphocyte count among HAART-naive individuals with no significant change observed among HAART-experienced ones. Viral load and haemoglobin concentration also remained unchanged following probiotic supplementation. Further rigorous and well-powered studies may evaluate the effect of probiotic supplementation on important clinical outcomes among PLHIV on HAART.

Bacterial Translocation As the Origin of Gram-Negative Rods Bloodstream Infection Among Older Patients in Rural Hospitals: A Cross-Sectional Study

Introduction Bloodstream infections caused by Gram-negative rods are a pressing concern for the aging global population, particularly in rural settings. This study investigates the prevalence and entry pathways of Gram-negative rod bloodstream infections in elderly patients at a rural Japanese hospital, aiming to clarify the frequency and associated factors of straightforward entry and bacterial translocation. Method In this cross-sectional study, we analyzed electronic medical records of patients over 18 years of age with symptomatic Gram-negative rod bloodstream infections at Unnan City Hospital, Japan, from September 2021 to August 2023. We used multivariate logistic regression to assess factors of age, sex, body mass index, care dependency, and comorbidities. Results Among the participants who met the inclusion criteria, significant differences were observed in age, sex, inpatient status, and prevalence of conditions like respiratory diseases and cancer between the straightforward entry and bacterial translocation groups. Escherichia coli was the most common pathogen identified. Conclusion The study emphasizes the need for tailored medical approaches for elderly patients with bloodstream infections, considering their unique health profiles and risks. It highlights the importance of age, inpatient status, and cancer in determining infection risks, pointing to areas for further research to enhance infection management and healthcare outcomes in older populations.

Macromolecule Translocation across the Intestinal Mucosa of HIV-Infected Patients by Transcytosis and through Apoptotic Leaks

Based on indirect evidence, increased mucosal translocation of gut-derived microbial macromolecules has been proposed as an important pathomechanism in HIV infection. Here, we quantified macromolecule translocation across intestinal mucosa from treatment-naive HIV-infected patients, HIV-infected patients treated by combination antiretroviral therapy, and HIV-negative controls and analyzed the translocation pathways involved. Macromolecule permeability was quantified by FITC-Dextran 4000 (FD4) and horseradish peroxidase (HRP) flux measurements. Translocation pathways were addressed using cold inhibition experiments. Tight junction proteins were characterized by immunoblotting. Epithelial apoptosis was quantified and translocation pathways were further characterized by flux studies in T84 cell monolayers using inducers and inhibitors of apoptosis and endocytosis. In duodenal mucosa of untreated but not treated HIV-infected patients, FD4 and HRP permeabilities were more than a 4-fold increase compared to the HIV-negative controls. Duodenal macromolecule permeability was partially temperature-dependent and associated with epithelial apoptosis without altered expression of the analyzed tight junction proteins. In T84 monolayers, apoptosis induction increased, and both apoptosis and endocytosis inhibitors reduced macromolecule permeability. Using quantitative analysis, we demonstrate the increased macromolecule permeability of the intestinal mucosa in untreated HIV-infected patients. Combining structural and mechanistic studies, we identified two pathways of increased macromolecule translocation in HIV infection: transcytosis and passage through apoptotic leaks.

Progressively confluent monkeypox lesions with necrosis

Human monkeypox virus became a burgeoning global health issue when outbreaks were identified in over 100 countries beginning in early 2022. We describe the case of a 38-year-old male with acquired immunodeficiency syndrome who presented one month after the development of painful anal lesions, subsequently confirmed to be monkeypox. The patient was unsuccessfully treated outpatient with multiple courses of oral tecovirimat before presenting to the emergency department for continual lesion progression. Given his AIDS, the patient was at-risk for poor response to oral treatment due to the potential for malabsorption from disruptions in his gut microbiome as well as inability to consume the recommended 25 grams of fat per dose needed for absorption. The identification of patients at-risk for severe disease is imperative as this population may be better suited for intravenous tecovirimat treatment due to the difficult parameters required for optimal absorption of oral therapy.

Aging With Grace for People Living With HIV: Strategies to Overcome Leaky Gut and Cytomegalovirus Coinfection

ABSTRACT

The intestinal epithelial layer acts as a mechanical and functional barrier between the intraluminal microbiota and the immunologically active submucosa. A progressive loss of gut barrier function (leaky gut) leads to enhanced translocation of microbial products, which in turn contributes as endotoxins to inflammaging. Th17 T cell represents the main immune sentinels in the gut epithelium, preventing aggression from commensal and pathogenic microbes. As HIV infection deeply affects gut Th17 function and increases gut permeability, microbial translocation occurs at high level in people living with HIV (PLWH) and has been associated with the development of non-AIDS comorbidities. Although the inflammatory role of endotoxins like lipopolysaccharide produced by Gram-negative bacteria is well-established, fungal products such as β-D-glucan emerge as new contributors. In addition, PLWH are more frequently infected with cytomegalovirus (CMV) than the general population. CMV infection is a well-described accelerator of immune aging, through the induction of expansion of dysfunctional CD8 T-cells as well as through enhancement of gut microbial translocation. We critically review immune mechanisms related to bacterial and fungal translocation, with a focus on the contribution of CMV coinfection in PLWH. Improving gut barrier dysfunction, microbial composition, and reducing microbial translocation constitute emerging strategies for the prevention and treatment of HIV-associated inflammation and may be relevant for age-related inflammatory conditions.

Overt IL-32 isoform expression at intestinal level during HIV-1 infection is negatively regulated by IL-17A

OBJECTIVES

Untreated HIV infection was previously associated with IL-32 overexpression in gut/intestinal epithelial cells (IEC). Here, we explored IL-32 isoform expression in the colon of people with HIV (PWH) receiving antiretroviral therapy (ART) and IL-32 triggers/modulators in IEC.

DESIGN

Sigmoid colon biopsies (SCB) and blood were collected from ART-treated PWH (HIV + ART; n = 17; mean age: 56 years; CD4+ cell counts: 679 cells/μl; time on ART: 72 months) and age-matched HIV-uninfected controls (HIVneg; n = 5). The IEC line HT-29 was used for mechanistic studies.

METHODS

Cells from SCB and blood were isolated by enzymatic digestion and/or gradient centrifugation. HT-29 cells were exposed to TLR1-9 agonists, TNF-α, IL-17A and HIV. IL-32α/β/γ/D/ε/θ and IL-17A mRNA levels were quantified by real-time RT-PCR. IL-32 protein levels were quantified by ELISA.

RESULTS

IL-32β/γ/ε isoform transcripts were detectable in the blood and SCB, with IL-32β mRNA levels being predominantly expressed in both compartments and at significantly higher levels in HIV + ART compared to HIVneg. IL-17A transcripts were only detectable in SCB, with increased IL-17A levels in HIVneg compared with HIV + ART and negatively correlated with IL-32β mRNA levels. IL-32β/γ/ε isoform mRNA were detected in HT-29 cells upon exposure to TNF-α, Poly I:C (TLR3 agonist), Flagellin (TLR-5 agonist) and HIV. IL-17A significantly decreased both IL-32 β/γ/ε mRNA and cell-associated IL-32 protein levels induced upon TNF-α and Poly I:C triggering.

CONCLUSION

We document IL-32 isoforms abundant in the colon of ART-treated PWH and reveal the capacity of the Th17 hallmark cytokine IL-17A to attenuate IL-32 overexpression in a model of inflamed IEC.

Fecal Metabolome Signature in the HIV-1 Elite Control Phenotype: Enrichment of Dipeptides Acts as an HIV-1 Antagonist but a Prevotella Agonist

HIV-1 elite controllers (EC) are a rare group among HIV-1-infected individuals who can naturally control viral replication for a prolonged period. Due to their heterogeneous nature, no universal mechanism could be attributed to the EC status; instead, several host and viral factors have been discussed as playing a role. In this study, we investigated the fecal metabolome and microbiome in a Swedish cohort of EC (n = 14), treatment-naive viremic progressors (VP; n = 16), and HIV-negative individuals (HC; n = 12). Fecal untargeted metabolomics was performed by four ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Molecular docking and biochemical microscale thermophoresis (MST) were used to describe the peptide-metabolite interactions. Single-cycle infectivity assays were performed in TZM-Bl cell lines using CCR5- and CXCR4-tropic HIV-1 strains. The microbiome analysis was performed using 16S rRNA sequencing. Th effects of metabolites on bacterial species viability were determined using several clinical isolates. We observed an enrichment of dipeptides in EC compared to VP and HC (adjusted P < 0.05). In silico analysis by molecular docking, in vitro biochemical assays, and ex vivo infection assays identified anti-HIV-1 properties for two dipeptides (WG and VQ) that could bind to the HIV-1 gp120, of which WG was more potent. The microbiome analysis identified enrichment of the genus Prevotella in EC, and these dipeptides supported bacterial growth of the genus Prevotella in vitro. The enrichments of the dipeptides and higher abundance of Prevotella have a distinct mechanism of elite control status in HIV-1 infection that influences host metabolism. IMPORTANCE HIV-1 elite controllers (EC) are a rare group among HIV-1-infected individuals who can naturally control viral replication for a prolonged period. Due to their heterogeneous nature, no universal mechanism could be attributed to the EC status; instead, several host and viral factors have been discussed as playing a role. In this study, we investigated the fecal metabolome and microbiome in a Swedish cohort of EC, treatment-naive viremic progressors (VP), and HIV-negative individuals (HC). We observed an enrichment of dipeptides in EC compared to the other two study groups. In silico and in vitro analyses identified anti-HIV-1 properties for two dipeptides that could bind to the HIV-1 gp120 and act as an HIV-1 antagonist. Furthermore, these dipeptides supported bacterial growth of the genus Prevotella in vitro that was enriched in EC, which influences host metabolism. Thus, increased levels of both dipeptides and Prevotella could provide beneficial effects for EC.

Sex-related differences in markers of immune activation in virologically suppressed HIV-infected patients

OBJECTIVES

Gender-specific studies remain a neglected area of biomedical research. Recent reports have emphasized that sex-related biological factors may affect disease progression during HIV-1 infection. The aim of this study was to investigate the influence of sex on the levels of immune activation in the gut and in peripheral blood of individuals with HIV treated with fully suppressive antiretroviral therapy (ART).

METHODS

Thirty individuals with HIV undergoing long-term fully suppressive ART were enrolled in this study. Lamina propria lymphocytes (LPL) and peripheral blood mononuclear cells (PBMCs) were isolated from gut biopsies collected by pancolonoscopy and peripheral blood samples. The expression of markers of immune activation was evaluated by multi-parametric flow cytometry. This is a sub analysis of ClinicalTrials.gov Identifier: NCT02276326 RESULTS: We observed differences in the levels of immune activation in the gut and in PBMCs, with values higher in the gut compartment compared to PBMCs. In addition, we found that the mean value of the levels of immune activation was higher in the women than in the men. Finally, we measured the markers of immune activation by mean relative difference (MRD) and confirmed the higher value in the women.

CONCLUSION

A significant sex-related difference in the level of immune activation was observed in a population of individuals with HIV on long-term ART. A more complete characterization of these differences may support the introduction of sex-specific approaches in the clinical management of individuals with HIV.

Increased IL-17 and/or IFN-γ producing T-cell subsets in gut mucosa of long-term-treated HIV-1-infected women

OBJECTIVE

The influence of sex on gut mucosal T-cell response in HIV-1 infection remains largely unknown. We explored whether the frequencies of interferon-γ and/or IL-17 producing naive, T central memory and T effector memory (TEM) CD4+ (Th1, Th17) and CD8+ T (Tc1, Tc17) cells measured in gut and peripheral districts differed between female and male HIV-1-infected patients.

METHODS

Thirty long-term-treated HIV-1-infected individuals were enrolled. The frequencies of Th1, Th17, Tc1, Tc17-cell subsets (single and double) were evaluated by multiparametric flow cytometry in lamina propria lymphocytes and peripheral blood mononuclear cells (PBMC).

RESULTS

A sex-based pattern was recorded in the differences of Th1, Th17, Tc1, Tc17-cell subset (single and double) frequencies between gut and peripheral blood. Female patients had stronger alterations in the gut mucosal T-cell repertoire, especially increased Th1, Th17, and Th1/Th17-cell subset frequencies, compared with the blood district than their male counterparts. Higher naive Tc1, Tc17, Tc1/Tc17, TEM Tc17, and TEM Tc1/Tc17 levels were also recorded in the gut mucosa than in the PBMC of HIV-1-infected women. Males and females also differed in their gut T-cell response, with women being characterized by higher Th1, Th17, Tc1, Tc17, and Th1/Th17 cells subset levels than men. By contrast, only TEM Th1/Th17 and TEM Tc17 in PBMC differed between males and females.

CONCLUSION

Sex-based differences observed in the gut T-cell response of HIV-1-infected patients might contribute to the disease dimorphism.

Oral Microbiome in HIV-Infected Women: Shifts in the Abundance of Pathogenic and Beneficial Bacteria Are Associated with Aging, HIV Load, CD4 Count, and Antiretroviral Therapy

Human immunodeficiency virus (HIV)-associated nonacquired immunodeficiency syndrome (AIDS) conditions, such as cardiovascular disease, diabetes, osteoporosis, and dementia are more prevalent in older than in young adult HIV-infected subjects. Although the oral microbiome has been studied as a window into pathogenesis in aging populations, its relationship to HIV disease progression, opportunistic infections, and HIV-associated non-AIDS conditions is not well understood. We utilized 16S rDNA-based pyrosequencing to compare the salivary microbiome in three groups: (1) Chronically HIV-infected women >50 years of age (aging); (2) HIV-infected women <35 years of age (young adult); and (3) HIV-uninfected age-matched women. We also examined correlations between salivary dysbiosis, plasma HIV RNA, CD4⁺ T cell depletion, and opportunistic oral infections. In both aging and young adult women, HIV infection was associated with salivary dysbiosis characterized by increased abundance of Prevotella melaninogenica and Rothia mucilaginosa. Aging was associated with increased bacterial diversity in both uninfected and HIV-infected women. In HIV-infected women with oral coinfections, aging was also associated with reduced abundance of the common commensal Veillonella parvula. Patients taking antiretroviral therapy showed increased numbers of Neisseria and Haemophilus. High plasma HIV RNA levels correlated positively with the presence of Prevotella and Veillonella, and negatively with the abundance of potentially beneficial Streptococcus and Lactobacillus. Circulating CD4⁺ T cell numbers correlated positively with the abundance of Streptococcus and Lactobacillus. Our findings extend previous studies of the role of the microbiome in HIV pathogenesis, providing new evidence that HIV infection is associated with a shift toward an increased pathogenic footprint of the salivary microbiome. Taken together, the data suggest a complex relationship, worthy of additional study, between chronic dysbiosis in the oral cavity, aging, viral burden, CD4⁺ T cell depletion, and long-term antiretroviral therapy.

[HIV infection as a cause of accelerated aging and frailty]

The HIV-infected population is aging due to the success of combination antiretroviral therapy, which prolongs survival, as well as the growing number of newly diagnosed cases in adults 50 years old and over. HIV-infected individuals suffer from an accelerated aging due to the persistent and chronic activation of the immune system that leads to immune exhaustion and accelerated immunosenescence, even when on optimal immuno-virological control treatment. The clinical expression of the immunosenescence state is an increased prevalence of aging-related non-HIV associated comorbidities and a rising prevalence of frailty occurring earlier than in the general population. Thus, HIV-infected patients are biologically older than their chronological age, and they suffer from aging-related problems, such as frailty, which should be assessed.

miR-130a and miR-212 Disrupt the Intestinal Epithelial Barrier through Modulation of PPARγ and Occludin Expression in Chronic Simian Immunodeficiency Virus-Infected Rhesus Macaques

Intestinal epithelial barrier dysfunction is a well-known sequela of HIV/SIV infection that persists despite antiretroviral therapy. Although inflammation is a triggering factor, the underlying molecular mechanisms remain unknown. Emerging evidence suggests that epithelial barrier function is epigenetically regulated by inflammation-induced microRNAs (miRNAs). Accordingly, we profiled and characterized miRNA/mRNA expression exclusively in colonic epithelium and identified 46 differentially expressed miRNAs (20 upregulated and 26 downregulated) in chronically SIV-infected rhesus macaques (Macaca mulatta). We bioinformatically crossed the predicted miRNA targets to transcriptomic data and characterized miR-130a and miR-212 as both were predicted to interact with critical epithelial barrier-associated genes. Next, we characterized peroxisome proliferator-activated receptor γ (PPARγ) and occludin (OCLN), predicted targets of miR-130a and miR-212, respectively, as their downregulation has been strongly linked to epithelial barrier disruption and dysbiosis. Immunofluorescence, luciferase reporter, and overexpression studies confirmed the ability of miR-130a and miR-212 to decrease protein expression of PPARγ and OCLN, respectively, and reduce transepithelial electrical resistance. Because Δ-9-tetrahydrocannabinol exerted protective effects in the intestine in our previous studies, we successfully used it to reverse miR-130a- and miR-212-mediated reduction in transepithelial electrical resistance. Finally, ex vivo Δ-9-tetrahydrocannabinol treatment of colon tissue from chronically SIV-infected rhesus macaques significantly increased PPARγ expression. Our findings suggest that dysregulated miR-130a and miR-212 expression in colonic epithelium during chronic HIV/SIV infection can facilitate epithelial barrier disruption by downregulating OCLN and PPARγ expression. Most importantly, our results highlight the beneficial effects of cannabinoids on epithelial barrier function in not just HIV/SIV but potentially other chronic intestinal inflammatory diseases.

Intestinal Barrier Impairment and Immune Activation in HIV-Infected Advanced Late Presenters are Not Dependent on CD4 Recovery

Damage of the mucosal barrier in HIV infection, microbial translocation, and immune activation can persist even in patients on successful antiretroviral therapy (ART) especially advanced late presenters. The aim of this study was to find factors that determine immune activation and bacterial translocation in HIV-infected advanced late presenters on suppressive ART. Forty-three late presenters (CD4 < 200 cells/µl prior to ART) on successful ART (more than 2 years of ART) with optimal and suboptimal CD4 recovery were enrolled into this study. The serum concentrations of intestinal fatty acid-binding peptide (I-FABP), zonulin-1, programmed cell death-1 protein (PCDP-1), and soluble (s)CD14 were measured using the ELISA test. We found higher serum levels of I-FABP and sCD14 in successfully antiretroviral-treated advanced late presenters compared to healthy subjects (p < 0.0001 and p = 0.0004). The serum concentration of PCDP-1 and zonulin-1 in HIV-infected patients did not differ from healthy controls. The levels of microbial translocation and immune activation markers were not associated with the degree of CD4 recovery. A serum concentration of I-FABP above 2.03 ng/ml was independently associated with a shorter ART (OR 0.78; p = 0.03). Older age was related to serum levels of sCD14 above 2.35 µg/ml (OR 1.1; p = 0.01). Higher serum levels of I-FABP and sCD14 in successfully antiretroviral-treated advanced late presenters compared to healthy subjects suggest an incomplete reconstruction of the intestinal barrier and sustained immune activation despite good CD4 recovery. It was not the CD4 level, but the length of the suppressive ART that was found to be associated with the restoration of the intestinal barrier.

Differentiating Immune Cell Targets in Gut-Associated Lymphoid Tissue for HIV Cure

The single greatest challenge to an HIV cure is the persistence of latently infected cells containing inducible, replication-competent proviral genomes, which constitute only a small fraction of total or infected cells in the body. Although resting CD4+ T cells in the blood are a well-known source of viral rebound, more than 90% of the body's lymphocytes reside elsewhere. Many are in gut tissue, where HIV DNA levels per million CD4+ T cells are considerably higher than in the blood. Despite the significant contribution of gut tissue to viral replication and persistence, little is known about the cell types that support persistence of HIV in the gut; importantly, T cells in the gut have phenotypic, functional, and survival properties that are distinct from T cells in other tissues. The mechanisms by which latency is established and maintained will likely depend on the location and cytokine milieu surrounding the latently infected cells in each compartment. Therefore, successful HIV cure strategies require identification and characterization of the exact cell types that support viral persistence, particularly in the gut. In this review, we describe the seeding of the latent HIV reservoir in the gut mucosa; highlight the evidence for compartmentalization and depletion of T cells; summarize the immunologic consequences of HIV infection within the gut milieu; propose how the damaged gut environment may promote the latent HIV reservoir; and explore several immune cell targets in the gut and their place on the path toward HIV cure.

The impact of aging on epithelial barriers

The epithelium has many critical roles in homeostasis, including an essential responsibility in establishing tissue barriers. In addition to the fundamental role in separating internal from external environment, epithelial barriers maintain nutrient, fluid, electrolyte and metabolic waste balance in multiple organs. While, by definition, barrier function is conserved, the structure of the epithelium varies across organs. For example, the skin barrier is a squamous layer of cells with distinct structural features, while the lung barrier is composed of a very thin single cell to minimize diffusion space. With the increased focus on age-dependent alterations in organ structure and function, there is an emerging interest in the impact of age on epithelial barriers. This review will focus on the impact of aging on the epithelial barrier of several organs, including the skin, lung, gastrointestinal tract and the kidney, at a structural and functional level.

Hepatocellular carcinoma: an evolving challenge in viral hepatitis and HIV coinfection

Liver-related morbidity and mortality is expanding in people living with HIV. Hepatocellular carcinoma (HCC), the third most lethal malignancy on a global scale, is a dominant complication of chronic liver disease and cirrhosis in patients with coexisting hepatitis. HIV infection further complicates the clinical heterogeneity of HCC, posing concurrent challenges stemming from the underlying immunological status of the patients and the ongoing need for combined antiretroviral therapy. In this article, we review the multiple clinical implications that characterize the multidisciplinary management of HCC in the context of HIV infection.

Reverse geroscience: how does exposure to early diseases accelerate the age-related decline in health?

Aging is the major risk factor for both the development of chronic diseases and loss of functional capacity. Geroscience provides links among the biology of aging, the biology of disease, and the physiology of frailty, three fields where enormous progress has been made in the last few decades. While, previously, the focus was on the role of aging in susceptibility to disease and disability, the other side of this relationship, which is the contribution of disease to aging, has been less explored at the molecular/cellular level. Indeed, the role of childhood or early adulthood exposure to chronic disease and/or treatment on accelerating aging phenotypes is well known in epidemiology, but the biological basis is poorly understood. A recent summit co-organized by the National Institutes of Health GeroScience Interest Group and the New York Academy of Sciences explored these relationships, using three chronic diseases as examples: cancer, HIV/AIDS, and diabetes. The epidemiological literature clearly indicates that early exposure to any of these diseases and/or their treatments results in an acceleration of the appearance of aging phenotypes, including loss of functional capacity and accelerated appearance of clinical symptoms of aging-related diseases not obviously related to the earlier event. The discussions at the summit focused on the molecular and cellular relationships between each of these diseases and the recently defined molecular and cellular pillars of aging. Two major conclusions from the meeting include the desire to refine an operational definition of aging and to concomitantly develop biomarkers of aging, in order to move from chronological to physiological age. The discussion also opened a dialogue on the possibility of improving late-life outcomes in patients affected by chronic disease by including age-delaying modalities along with the standard care for the disease in question.

Ageing and inflammation in patients with HIV infection

Nowadays, HIV⁺ patients have an expected lifespan that is only slightly shorter than healthy individuals. For this reason, along with the fact that infection can be acquired at a relatively advanced age, the effects of ageing on HIV⁺ people have begun to be evident. Successful anti-viral treatment is, on one hand, responsible for the development of side effects related to drug toxicity; on the other hand, it is not able to inhibit the onset of several complications caused by persistent immune activation and chronic inflammation. Therefore, patients with a relatively advanced age, i.e. aged more than 50 years, can experience pathologies that affect much older citizens. HIV⁺ individuals with non-AIDS-related complications can thus come to the attention of clinicians because of the presence of neurocognitive disorders, cardiovascular diseases, metabolic syndrome, bone abnormalities and non-HIV-associated cancers. Chronic inflammation and immune activation, observed typically in elderly people and defined as 'inflammaging', can be present in HIV⁺ patients who experience a type of premature ageing, which affects the quality of life significantly. This relatively new condition is extremely complex, and important factors have been identified as well as the traditional behavioural risk factors, e.g. the toxicity of anti-retroviral treatments and the above-mentioned chronic inflammation leading to a functional decline and a vulnerability to injury or pathologies. Here, we discuss the role of inflammation and immune activation on the most important non-AIDS-related complications of chronic HIV infection, and the contribution of aging per se to this scenario.

Gut epithelial barrier dysfunction in human immunodeficiency virus-hepatitis C virus coinfected patients: Influence on innate and acquired immunity

Even in cases where viral replication has been controlled by antiretroviral therapy for long periods of time, human immunodeficiency virus (HIV)-infected patients have several non-acquired immunodeficiency syndrome (AIDS) related co-morbidities, including liver disease, cardiovascular disease and neurocognitive decline, which have a clear impact on survival. It has been considered that persistent innate and acquired immune activation contributes to the pathogenesis of these non-AIDS related diseases. Immune activation has been related with several conditions, remarkably with the bacterial translocation related with the intestinal barrier damage by the HIV or by hepatitis C virus (HCV)-related liver cirrhosis. Consequently, increased morbidity and mortality must be expected in HIV-HCV coinfected patients. Disrupted gut barrier lead to an increased passage of microbial products and to an activation of the mucosal immune system and secretion of inflammatory mediators, which in turn might increase barrier dysfunction. In the present review, the intestinal barrier structure, measures of intestinal barrier dysfunction and the modifications of them in HIV monoinfection and in HIV-HCV coinfection will be considered. Both pathogenesis and the consequences for the progression of liver disease secondary to gut microbial fragment leakage and immune activation will be assessed.

Does the Intestinal Microbiota Explain Differences in the Epidemiology of Liver Disease between East and West?

Changes in bacterial communities are associated with the pathogenesis of many diseases including inflammatory bowel disease and liver disease. Dysbiosis can induce intestinal inflammation resulting in increased intestinal permeability and bacterial translocation. The majority of chronic liver diseases are associated with bacterial translocation resulting in or enhancing an inflammatory response in the liver. Intestinal inflammation and a dysfunctional intestinal barrier are not sufficient to cause liver disease in the absence of an additional liver insult. In this article, the authors summarize differences in intestinal microbiota composition between Eastern and Western countries. The authors specifically discuss whether differences in microbiota composition could explain the epidemiological differences in liver disease found in Asia and Europe/the USA.

HIV and the spectrum of human disease

Infection with the human immunodeficiency virus (HIV) causes systemic T cell destruction and reduced cell-mediated immunity that leads to a wide range of opportunistic infections and cancers. Second, it directly damages many tissues - gut, brain, lung - through mononuclear cell infection and activation. Third, through immune activation and effects on endothelia, it can cause more subtle systemic organ damage, such as chronic cardiovascular, hepatic, pulmonary and central nervous system disease. Antiretroviral treatment has enabled HIV-infected persons to live with chronic infection, although with some side-effects and mortality, including reactions due to the immune reconstitution inflammatory syndrome (IRIS). As cohorts of infected people get older, age-related diseases will combine with chronic HIV infection to produce disabilities whose scale is not yet understood. HIV is detectable in tissues by immunohistochemistry when infection loads are high, such as at first presentation. Pathologists should proactively consider HIV disease in routine diagnostic work, so as to identify more HIV-infected patients and enable their optimal management.

Is intestinal inflammation linking dysbiosis to gut barrier dysfunction during liver disease?

Changes in the intestinal microbiota composition contribute to the pathogenesis of many disorders including gastrointestinal and liver diseases. Recent studies have broadened our understanding of the "gut-liver" axis. Dietary changes, other environmental and genetic factors can lead to alterations in the microbiota. Dysbiosis can further disrupt the integrity of the intestinal barrier leading to pathological bacterial translocation and the initiation of an inflammatory response in the liver. In this article, the authors dissect the different steps involved in disease pathogenesis to further refine approaches for the medical management of liver diseases. The authors will specifically discuss the role of dysbiosis in inducing intestinal inflammation and increasing intestinal permeability.

Ethnicity and Smoking-Associated DNA Methylation Changes at HIV Co-Receptor GPR15

Smoking is associated with poorer health outcomes for both African and European Americans. In order to better understand whether ethnic-specific genetic variation may underlie some of these differences, we compared the smoking-associated genome-wide methylation signatures of African Americans with those of European Americans, and followed up this analysis with a focused examination of the most ethnically divergent locus, cg19859270, at the GPR15 gene. We examined the association of methylation at this locus to the rs2230344 SNP and GPR15 gene and protein expression. Consistent with prior analyses, AHRR residue cg05575921 was the most differentially methylated residue in both African Americans and European Americans. However, the second most differentially methylated locus in African Americans, cg19859270, was only modestly differentially methylated in European Americans. Interrogation of the methylation status of this CpG residue found in GPR15, a chemokine receptor involved in HIV pathogenesis, showed a significant interaction of ethnicity with smoking as well as a marginal effect of genotype at rs2230344, a neighboring non-synonymous SNP, but only among African Americans. Gene and protein expression analyses showed that demethylation at cg19859270 was associated with an increase in both mRNA and protein levels. Since GPR15 is involved in the early stages of viral replication for some HIV-1 and HIV-2 isolates, and the prevalence of HIV is increased in African Americans and smokers, these data support a possible role for GPR15 in the ethnically dependent differential prevalence of HIV.

Current understanding of HIV-1 and T-cell adaptive immunity: progress to date

The cellular immune response to human immunodeficiency virus (HIV) has different components originating from both the adaptive and innate immune systems. HIV cleverly utilizes the host machinery to survive by its intricate nature of interaction with the host immune system. HIV evades the host immune system at innate ad adaptive, allows the pathogen to replicate and transmit from one host to another. Researchers have shown that HIV has multipronged effects especially on the adaptive immunity, with CD4(+) cells being the worst effect T-cell populations. Various analyses have revealed that, the exposure to HIV results in clonal expansion and excessive activation of the immune system. Also, an abnormal process of differentiation has been observed suggestive of an alteration and blocks in the maturation of various T-cell subsets. Additionally, HIV has shown to accelerate immunosenescence and exhaustion of the overtly activated T-cells. Apart from causing phenotypic changes, HIV has adverse effects on the functional aspect of the immune system, with evidences implicating it in the loss of the capacity of T-cells to secrete various antiviral cytokines and chemokines. However, there continues to be many aspects of the immune- pathogenesis of HIV that are still unknown and thus required further research in order to convert the malaise of HIV into a manageable epidemic.