Gut epithelial barrier and systemic inflammation during chronic HIV infection

The Tryptophan-Kynurenine pathway in people living with HIV: a systematic review

PURPOSE

HIV-1 disrupts the metabolic profile of people living with HIV (PLWH), including the Tryptophan-Kynurenine (Trp-Kyn) pathway, linked to disease outcomes and comorbidities. Despite numerous studies, consensus on key dysregulated metabolites in antiretroviral therapy (ART)-treated PLWH is lacking. This systematic review compiles data to identify and highlight the most noteworthy Trp-Kyn metabolites.

METHODS

PubMed, Scopus, and Web of Science databases were searched using a search protocol specifically designed for this study. Studies that investigated the levels of metabolites in the Trp-Kyn pathway in the peripheral blood of PLWH on ART, as well as in healthy control groups were included.

RESULTS

Thirteen metabolomic studies that investigated this pathway met our inclusion criteria. The findings revealed that Trp, Kyn, and the Kyn/Trp ratio (indicative of indoleamine 2,3-dioxygenase IDO activity) were the most investigated metabolites in this metabolic pathway. Evidence consistently demonstrated that Trp levels were lower in PLWH, while predicted IDO activity was consistently higher. Despite the widespread investigation of Kyn, there was no clear consensus on its levels in PLWH, with some studies reporting higher levels and others finding no significant differences compared to HIV-negative controls.

CONCLUSION

In the modern ART era, Trp metabolism and IDO activity may play key regulatory roles in HIV-1 pathogenesis, as evidenced by the consistent patterns observed across various studies. These metabolites and related pathways warrant further investigation as potential targets for improved diagnostics, prognostics, and therapeutics in the context of HIV-1.

The intestinal interferon system and specialized enterocytes as putative drivers of HIV latency

The barrier to HIV cure is the HIV reservoir, which is composed of latently infected CD4+ T cells and myeloid cells that carry stably integrated and replication-competent provirus. The gastrointestinal tract (GIT) contains a substantial part of the HIV reservoir and its immunophysiology could be especially conducive for HIV persistence and reactivation. However, the exact cellular microenvironment and molecular mechanisms that govern the renewal of provirus-harboring cells and proviral reactivation in the GIT remain unclear. In this review, we outline the evidence supporting an overarching hypothesis that interferon activity driven by specialized enterocytes creates a microenvironment that fosters proliferation of latently infected CD4+ T cells and sporadic HIV reactivation from these cells. First, we describe unique immunologic features of the gastrointestinal associated lymphoid tissue (GALT), specifically highlighting IFN activity in specialized enterocytes and potential interactions between these cells and neighboring HIV susceptible cells. Then, we will describe dysregulation of IFN signaling in HIV infection and how IFN dysregulation in the GALT may contribute to the persistence and reactivation of the latent HIV reservoir. Finally, we will speculate on the clinical implications of this hypothesis for HIV cure strategies and outline the next steps.

Taxonomic and functional profile of the anorectal microbiota in HIV-positive and HIV-negative men who have sex with men, using a metagenomic approach

INTRODUCTION

The study of bacterial diversity in human samples is crucial for developing biomarkers of health and disease. This research characterized the taxonomic and functional diversity of the anorectal bacterial microbiota in men who hae sex with men (MSM) with HIV compared to men from this group without HIV.

MATERIALS AND METHODS

In July and August 2023, self-collected anorectal swabs were obtained. DNA was extracted from each sample, and metagenomic sequencing was performed. With the obtained data, alpha and beta diversity, bacterial abundance, differential operational taxonomic units, and functional diversity were determined.

RESULTS

Initially, 90 samples were collected, with 20 discarded due to having less than 200 ng of DNA and 15 due to incomplete sequencing, leaving 55 samples analysed (15 HIV-positive and 40 HIV-negative). No significant differences were found between groups in terms of alpha diversity (Shannon index p = 0.45) and beta diversity (PERMANOVA R = -0.03). Prevotella was identified as the most abundant genus in both groups. Twelve genes were found to be more abundant in the anorectal microbiota of the HIV group, which promote bacterial growth, colonization and survival.

CONCLUSION

Alterations in the anorectal microbiota could influence the pathogenesis of HIV and its complications in this population, underscoring the need to investigate these mechanisms and explore interventions to improve health. Longitudinal studies are needed to analyse changes in the anorectal microbiota during HIV infection and its response to treatment, integrating metagenomic, clinical, and immunological data to better understand the interactions between HIV, the microbiota and host health.

Tumour necrosis factor-α induces macromolecule translocation in HIV-derived duodenal organoids

Background

Disease progression from human immunodeficiency virus (HIV) infection to acquired immunodeficiency syndrome (AIDS) is marked by chronic immune activation, partly due to increased translocation of gut-derived microbial antigens. Elevated mucosal tumour necrosis factor-α (TNF-α) and resulting epithelial cell apoptosis may be the etiology. However, studies using carcinoma cell lines have failed to find a causal link, possibly due to cellular abnormalities related to the malignant transformation of these immortal cell lines.

Methods

We established intestinal organoid monolayers from healthy controls and HIV-infected adults and characterized their growth dynamics and cellular composition. We then examined the effects of HIV-associated cytokines on transepithelial resistance (TER), apoptosis and macromolecule translocation.

Results

Organoid monolayers from HIV-infected patients grew similarly to healthy controls, forming confluent monolayers within one to two weeks containing enterocytes, Paneth, goblet and stem cells. IFN-γ synergized with TNF-α, allowing TNF-α to cause caspase-mediated apoptosis and TER reduction within 5 ± 3 hours, reflecting patient sample heterogeneity. This led to paracellular passage of 4 kDa Dextran and transcytosis of 44 kDa horse radish peroxidase, both of which could be blocked by pan-caspase inhibitor, Q-VD-Oph.

Conclusion

Our study confirms that intestinal organoid monolayers from biopsies of HIV-infected individuals can be used to study apoptosis-related epithelial barrier dysfunction and macromolecular translocation. We provide direct evidence that TNF-α-induced apoptosis triggered two pathways of macromolecular translocation: paracellular passage via apoptotic leaks and transcytosis. Therapies targeting apoptosis may be useful in preventing disease progression from HIV to AIDS.

A review of gut failure as a cause and consequence of critical illness

In critical illness, all elements of gut function are perturbed. Dysbiosis develops as the gut microbial community loses taxonomic diversity and new virulence factors appear. Intestinal permeability increases, allowing for translocation of bacteria and/or bacterial products. Epithelial function is altered at a cellular level and homeostasis of the epithelial monolayer is compromised by increased intestinal epithelial cell death and decreased proliferation. Gut immunity is impaired with simultaneous activation of maladaptive pro- and anti-inflammatory signals leading to both tissue damage and susceptibility to infections. Additionally, splanchnic vasoconstriction leads to decreased blood flow with local ischemic changes. Together, these interrelated elements of gastrointestinal dysfunction drive and then perpetuate multi-organ dysfunction syndrome. Despite the clear importance of maintaining gut homeostasis, there are very few reliable measures of gut function in critical illness. Further, while multiple therapeutic strategies have been proposed, most have not been shown to conclusively demonstrate benefit, and care is still largely supportive. The key role of the gut in critical illness was the subject of the tenth Perioperative Quality Initiative meeting, a conference to summarize the current state of the literature and identify key knowledge gaps for future study. This review is the product of that conference.

Biomarkers of microbial translocation and generalized inflammation are associated with frailty among people with HIV

BACKGROUND

Frailty occurs at higher rates and younger ages among people with HIV (PWH) compared with the general population and is often attributed to chronic inflammation and subsequent immune exhaustion. We assessed how inflammatory biomarkers are associated with frailty among PWH.

METHODS

The Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems (CNICS) cohort is comprised of adult PWH in care at 10 sites, and harmonizes demographic, clinical, and patient-reported outcomes (PRO) data. A panel of 13 inflammatory biomarkers was collected from a subset of virally suppressed PWH once per person between 2010 and 2018. Frailty was measured with a validated PRO phenotype, scored 0-4, from biomarker collection date through July 2022. With adjusted linear mixed models, we estimated longitudinal associations between standard deviation-scaled log 2 -transformed biomarkers and frailty score.

RESULTS

Among 273 PWH, most were men (91%), average age at baseline was 45, 42% were non-Hispanic White whereas 35% were non-Hispanic Black, and average follow-up time was 5.5 years. Several biomarkers were associated with higher frailty, including those linked to microbial translocation (sCD14, LBP, KT ratio) and systemic inflammation (CRP, IL-6, suPAR, sTNFR1, sTNFR2). Higher IL-6 was associated with a 0.25-point higher frailty score [95% confidence interval (CI) 0.12-0.39]. Higher sTNFR1 [0.35 (0.13-0.56)], sCD14 [0.21 (0.11-0.31)], and suPAR [0.24 (0.11-0.36)] levels were also associated with higher frailty scores over follow-up.

CONCLUSION

Higher levels of biomarkers linked to microbial translocation and systemic inflammation are associated with higher average frailty scores over time in a cohort of virally suppressed PWH, highlighting these pathways as potential interventional targets for mitigating frailty in PWH.

Incomplete Immune Reconstitution and Traditional Chinese Medicine in Patients with HIV/AIDS: Challenges and Perspectives

Antiretroviral therapy can reduce human immunodeficiency virus (HIV) load to undetectable levels and restore CD4+ T cells to rebuild immune function in patients with HIV. However, some patients fail to achieve immune reconstitution despite treatment. Traditional Chinese medicine is an important branch of complementary and alternative medicine for the treatment of HIV infection, and a growing number of studies has demonstrated that traditional Chinese medicine can increase CD4+ T cell counts in patients, thereby promoting immune reconstitution, ameliorating symptoms and signs, and improving quality of life. Here, we review pathogenesis in immunological non-responders and research into their treatment with traditional Chinese medicine. Furthermore, we summarize potential future research directions, including elucidation of how traditional Chinese medicine can regulate CD4+ T cells to reduce opportunistic infections and improve quality of life in immunological non-responders.

Epigenetic modulation of NLRP6 inflammasome sensor as a therapeutic modality to reduce necroptosis-driven gastrointestinal mucosal dysfunction in HIV/SIV infection

The epigenetic mechanisms driving persistent gastrointestinal mucosal dysfunction in HIV/SIV infection is an understudied topic. Using reduced-representation bisulfite sequencing, we identified HIV/SIV infection in combination anti-retroviral therapy (cART)-naive rhesus macaques (RMs) to induce marked hypomethylation throughout promoter-associated CpG islands (paCGIs) in genes related to inflammatory response ( NLRP6, cGAS ), cellular adhesion and proliferation in colonic epithelial cells (CEs). Moreover, low-dose delta-9-tetrahydrocannabinol (THC) administration reduced NLRP6 protein expression in CE by hypermethylating the NLRP6 paCGI and blocked polyI:C induced NLRP6 upregulation in vitro. In cART suppressed SIV-infected RMs, NLRP6 protein upregulation associated with significantly increased expression of necroptosis-driving proteins; phosphorylated-RIPK3(Ser199), phosphorylated-MLKL(Thr357/Ser358), and HMGB1. Most strikingly, supplementing cART with THC effectively reduced NLRP6 and necroptosis-driving protein expression to pre-infection levels. These findings for the first time demonstrate that NLRP6 upregulation and ensuing activation of necroptosis promote HIV/SIV-induced gastrointestinal mucosal dysfunction and that epigenetic modulation using phytocannabinoids represents a feasible therapeutic modality for alleviating HIV/SIV-induced gastrointestinal inflammation and associated comorbidities.

Nucleic acid liquid biopsies in cardiovascular disease: Cell-free RNA liquid biopsies in cardiovascular disease

Cardiovascular diseases (CVD) and their complications continue to be the leading cause of mortality globally. With recent advancements in molecular analytics, individualized treatments are gradually applied to the diagnosis and treatment of CVD. In the field of diagnostics, liquid biopsy combined with modern analytical technologies is the most popular natural source to identify disease biomarkers, as has been successfully demonstrated in the cancer field. While it is not easy to obtain any diseased tissue for different types of CVD such as atherosclerosis, deep vein thrombosis or stroke, liquid biopsies provide a simple and non-invasive alternative to surgical tissue specimens to obtain dynamic molecular information reflecting disease states. The release of cell-free ribonucleic acids (cfRNA) from stressed/damaged/dying and/or necrotic cells is a common physiological phenomenon. CfRNAs are a heterogeneous population of various types of extracellular RNA found in body fluids (blood, urine, saliva, cerebrospinal fluid) or in association with vascular/atherosclerotic tissue, offering insights into disease pathology on a diagnostic front. In particular, cf-ribosomal RNA has been shown to act as a damaging molecule in several cardio-vascular disease conditions. Moreover, such pathophysiological functions of cfRNA in CVD have been successfully antagonized by the administration of RNases. In this review, we discuss the origin, structure, types, and potential utilization of cfRNA in the diagnosis of CVD. Together with the analysis of established CVD biomarkers, the profiling of cfRNA in body fluids may thereby provide a promising approach for early disease detection and monitoring.

Crotonylation modification and its role in diseases

Protein lysine crotonylation is a novel acylation modification discovered in 2011, which plays a key role in the regulation of various biological processes. Thousands of crotonylation sites have been identified in histone and non-histone proteins over the past decades. Crotonylation is conserved and is regulated by a series of enzymes including "writer", "eraser", and "reader". In recent years, crotonylation has received extensive attention due to its breakthrough progress in reproduction, development and pathogenesis of diseases. Here we brief the crotonylation-related enzyme systems, biological functions, and diseases caused by abnormal crotonylation, which provide new ideas for developing disease intervention and treatment regimens.

Gastrointestinal germinal center B cell depletion and reduction in IgA+ plasma cells in HIV-1 infection

Gastrointestinal (GI) B cells and plasma cells (PCs) are critical to mucosal homeostasis and the host response to HIV-1 infection. Here, high-resolution mapping of human B cells and PCs sampled from the colon and ileum during both viremic and suppressed HIV-1 infection identified a reduction in germinal center (GC) B cells and follicular dendritic cells (FDCs) during HIV-1 viremia. Immunoglobulin A-positive (IgA+) PCs are the major cellular output of intestinal GCs and were significantly reduced during viremic HIV-1 infection. PC-associated transcriptional perturbations, including type I interferon signaling, persisted in antiretroviral therapy (ART)-treated individuals, suggesting ongoing disruption of the intestinal immune milieu during ART. GI humoral immune perturbations were associated with changes in the intestinal microbiome composition and systemic inflammation. These findings highlight a key immune defect in the GI mucosa due to HIV-1 viremia.

Gastrointestinal germinal center B cell depletion and reduction in IgA + plasma cells in HIV-1 infection

Gastrointestinal (GI) B cells and plasma cells (PCs) are critical to mucosal homeostasis and the host response to HIV-1 infection. Here, high resolution mapping of human B cells and PCs sampled from the colon and ileum during both viremic and suppressed HIV-1 infection identified a reduction in germinal center (GC) B cells and follicular dendritic cells (FDCs) during HIV-1 viremia. IgA + PCs are the major cellular output of intestinal GCs and were significantly reduced during viremic HIV-1 infection. PC-associated transcriptional perturbations, including type I interferon signaling, persisted in antiretroviral therapy (ART)-treated individuals, suggesting ongoing disruption of the intestinal immune milieu during ART. GI humoral immune perturbations were associated with changes in the intestinal microbiome composition and systemic inflammation. These findings highlight a key immune defect in the GI mucosa due to HIV-1 viremia.

One Sentence Summary

Intestinal germinal center B cell reduction in HIV-1 infection linked to reduced IgA + plasma cells and systemic inflammation.

Dysregulation of Gut Microbiota-Derived Neuromodulatory Amino Acid Metabolism in Human Immunodeficiency Virus-Associated Neurocognitive Disorder: An Integrative Metagenomic and Metabolomic Analysis

OBJECTIVE

Although accumulating evidence implicating altered gut microbiota in human immunodeficiency virus (HIV) infection and neurodegenerative disorders; however, the association between dysbiosis of the gut microbiota and metabolites in the pathogenesis of HIV-associated neurocognitive disorder (HAND) remains unclear.

METHODS

Fecal and plasma samples were obtained from 3 cohorts (HAND, HIV-non-HAND, and healthy controls), metagenomic analysis and metabolomic profiling were performed to investigate alterations in the gut microbial composition and circulating metabolites in HAND.

RESULTS

The gut microbiota of people living with HIV (PLWH) had an increased relative abundance of Prevotella and a decreased relative abundance of Bacteroides. In contrast, Prevotella and Megamonas were substantially decreased, and Bacteroides and Phocaeicola were increased in HAND patients. Moreover, untargeted metabolomics identified several neurotransmitters and certain amino acids associated with neuromodulation, and the differential metabolic pathways of amino acids associated with neurocognition were depleted in HAND patients. Notably, most neuromodulatory metabolites are associated with an altered abundance of specific gut bacteria.

INTERPRETATION

Our findings provide new insights into the intricate interplay between the gut and microbiome-brain axis in the pathogenesis of HAND, highlighting the potential for developing novel therapeutic strategies that specifically target the gut microbiota. ANN NEUROL 2024;96:306-320.

Elevated Inflammation Associated with Markers of Neutrophil Function and Gastrointestinal Disruption in Pilot Study of Plasmodium fragile Co-Infection of ART-Treated SIVmac239+ Rhesus Macaques

Human immunodeficiency virus (HIV) and malaria, caused by infection with Plasmodium spp., are endemic in similar geographical locations. As a result, there is high potential for HIV/Plasmodium co-infection, which increases the pathology of both diseases. However, the immunological mechanisms underlying the exacerbated disease pathology observed in co-infected individuals are poorly understood. Moreover, there is limited data available on the impact of Plasmodium co-infection on antiretroviral (ART)-treated HIV infection. Here, we used the rhesus macaque (RM) model to conduct a pilot study to establish a model of Plasmodium fragile co-infection during ART-treated simian immunodeficiency virus (SIV) infection, and to begin to characterize the immunopathogenic effect of co-infection in the context of ART. We observed that P. fragile co-infection resulted in parasitemia and anemia, as well as persistently detectable viral loads (VLs) and decreased absolute CD4+ T-cell counts despite daily ART treatment. Notably, P. fragile co-infection was associated with increased levels of inflammatory cytokines, including monocyte chemoattractant protein 1 (MCP-1). P. fragile co-infection was also associated with increased levels of neutrophil elastase, a plasma marker of neutrophil extracellular trap (NET) formation, but significant decreases in markers of neutrophil degranulation, potentially indicating a shift in the neutrophil functionality during co-infection. Finally, we characterized the levels of plasma markers of gastrointestinal (GI) barrier permeability and microbial translocation and observed significant correlations between indicators of GI dysfunction, clinical markers of SIV and Plasmodium infection, and neutrophil frequency and function. Taken together, these pilot data verify the utility of using the RM model to examine ART-treated SIV/P. fragile co-infection, and indicate that neutrophil-driven inflammation and GI dysfunction may underlie heightened SIV/P. fragile co-infection pathogenesis.

From dysbiosis to defense: harnessing the gut microbiome in HIV/SIV therapy

BACKGROUND

Although the microbiota has been extensively associated with HIV pathogenesis, the majority of studies, particularly those using omics techniques, are largely correlative and serve primarily as a basis for hypothesis generation. Furthermore, most have focused on characterizing the taxonomic composition of the bacterial component, often overlooking other levels of the microbiome. The intricate mechanisms by which the microbiota influences immune responses to HIV are still poorly understood. Interventional studies on gut microbiota provide a powerful tool to test the hypothesis of whether we can harness the microbiota to improve health outcomes in people with HIV.

RESULTS

Here, we review the multifaceted role of the gut microbiome in HIV/SIV disease progression and its potential as a therapeutic target. We explore the complex interplay between gut microbial dysbiosis and systemic inflammation, highlighting the potential for microbiome-based therapeutics to open new avenues in HIV management. These include exploring the efficacy of probiotics, prebiotics, fecal microbiota transplantation, and targeted dietary modifications. We also address the challenges inherent in this research area, such as the difficulty in inducing long-lasting microbiome alterations and the complexities of study designs, including variations in probiotic strains, donor selection for FMT, antibiotic conditioning regimens, and the hurdles in translating findings into clinical practice. Finally, we speculate on future directions for this rapidly evolving field, emphasizing the need for a more granular understanding of microbiome-immune interactions, the development of personalized microbiome-based therapies, and the application of novel technologies to identify potential therapeutic agents.

CONCLUSIONS

Our review underscores the importance of the gut microbiome in HIV/SIV disease and its potential as a target for innovative therapeutic strategies.

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

INTRODUCTION

Impairment of the gastrointestinal barrier leads to microbial translocation and peripheral immune activation, which are linked to disease progression. Data in the setting of primary HIV/SIV infection suggest that gut barrier damage is one of the first events of the pathogenic cascade, preceding mucosal immune dysfunction and microbial translocation. We assessed gut structure and immunity as well as microbial translocation in acutely and chronically-infected, combination antiretroviral therapy (cART)-naive individuals.

METHODS

Fifteen people with primary HIV infection (P-HIV) and 13 with chronic HIV infection (C-HIV) c-ART-naive participants were cross-sectionally studied. Gut biopsies were analysed in terms of gut reservoirs (total, integrated and unintegrated HIV DNA); tight junction proteins (E-cadherin, Zonula Occludens-1), CD4 + expression, neutrophil myeloperoxidase (histochemical staining); collagen deposition (Masson staining). Flow cytometry was used to assess γδ T-cell frequency (CD3 + panγδ+Vδ1+/Vδ2+). In plasma, we measured microbial translocation (LPS, sCD14, EndoCAb) and gut barrier function (I-FABP) markers (ELISA).

RESULTS

P-HIV displayed significantly higher tissue HIV DNA, yet neutrophil infiltration and collagen deposition in the gut were similar in the two groups. In contrast, microbial translocation markers were significantly lower in P-HIV compared with C-HIV. A trend to higher mucosal E-cadherin, and gut γδ T-cells was also observed in P-HIV.

CONCLUSION

Early HIV infection features higher HIV DNA in the gut, yet comparable mucosal alterations to those observed in chronic infection. In contrast, microbial translocation is contained in primary HIV infection, likely because of a partial preservation of E-cadherin and mucosal immune subsets, namely γδ T-cells.

The presence of enteropathy in HIV infected children on antiretroviral therapy in Malawi

BACKGROUND

Undernutrition and malnutrition in children in low- and middle-income countries contribute to high mortality rates. Stunting, a prevalent form of malnutrition, is associated with educational and productivity losses. Environmental enteric dysfunction (EED) and human immunodeficiency virus (HIV) infection worsen these conditions. This study seeks to investigate the presence of enteropathy using EED fecal biomarkers in HIV-infected children who are stable on antiretroviral therapy (ART) across various nutritional statuses. By understanding the interplay between EED, HIV, and nutritional status, this study aims to provide insights that can inform targeted interventions to optimize nutritional outcomes in HIV infected children.

METHODS/PRINCIPAL FINDINGS

This study evaluated the levels of alpha-1-antitrypsin, calprotectin and myeloperoxidase in frozen fecal samples from 61 HIV infected (mean age 9.16 ±3.08 years) and 31 HIV uninfected (6.65 ±3.41 years) children in Malawi. Anthropometric measurements and clinical data were collected. The height-for-age z-score (-1.66 vs -1.27, p = 0.040) and BMI-for-age z-score (-0.36 vs 0.01, p = 0.037) were lower in HIV infected children. Enzyme-linked immunosorbent assays were used to measure biomarker concentrations. Statistical tests were applied to compare biomarker levels based on HIV status and anthropometric parameters. Myeloperoxidase, alpha-1-antitrypsin, and calprotectin concentrations did not differ between HIV infected and HIV uninfected children of different age groups. In HIV infected children from 5-15 years, there is no difference in biomarker concentration between the stunted and non-stunted groups.

CONCLUSION/SIGNIFICANCE

Our study found a higher prevalence of stunting in HIV infected children compared to uninfected children, but no significant differences in biomarker concentrations. This suggests no causal relationship between enteropathy and stunting in HIV infected children. These results contribute to the understanding of growth impairment in HIV infected children and emphasize the need for further research, particularly a longitudinal, biopsy-controlled study.

The microbiome as a biomarker of anal precancerous lesions in people with HIV

PURPOSE OF REVIEW

Early detection and treatment of human papillomavirus (HPV)-related anal dysplasia in some high-risk groups can help anal cancer prevention, but new tools to improve diagnostic and risk assessment are needed. Here, we aim to discuss the evidence on the role of the microbiome as a potential biomarker for anal high-grade squamous intraepithelial lesions (HSILs) in people with HIV (PWH).

RECENT FINDINGS

This review covers relevant studies on the links between the microbiome and HPV infection, cervical dysplasia/cancer, and anal HPV disease. It focuses on anal samples and precancerous lesions.

SUMMARY

The review highlights the promising potential of the anal microbiome as a novel biomarker for precancerous lesions in people with HIV, while also discussing limitations and future research needs.

Longitudinal patterns of inflammatory mediators after acute HIV infection correlate to intact and total reservoir

Background

Despite the beneficial effects of antiretroviral therapy (ART) initiation during acute HIV infection (AHI), residual immune activation remains a hallmark of treated HIV infection.

Methods

Plasma concentrations of 40 mediators were measured longitudinally in 39 early treated participants of a Belgian AHI cohort (HIV+) and in 21 HIV-negative controls (HIV-). We investigated the association of the inflammatory profile with clinical presentation, plasma viral load, immunological parameters, and in-depth characterization of the HIV reservoir.

Results

While levels of most soluble mediators normalized with suppressive ART, we demonstrated the persistence of a pro-inflammatory signature in early treated HIV+ participants in comparison to HIV- controls. Examination of these mediators demonstrated a correlation with their levels during AHI, which seemed to be viremia-driven, and suggested involvement of an activated myeloid compartment, IFN-γ-signaling, and inflammasome-related pathways. Interestingly, some of these pro-inflammatory mediators correlated with a larger reservoir size and slower reservoir decay. In contrast, we also identified soluble mediators which were associated with favorable effects on immunovirological outcomes and reservoir, both during and after AHI.

Conclusion

These data highlight how the persistent pro-inflammatory profile observed in early ART treated individuals is shaped during AHI and is intertwined with viral dynamics.

The bidirectional relationship between opioids and the gut microbiome: Implications for opioid tolerance and clinical interventions

Opioids are widely used in treating patients with acute and chronic pain; however, this class of drugs is also commonly abused. Opioid use disorder and associated overdoses are becoming more prevalent as the opioid crisis continues. Chronic opioid use is associated with tolerance, which decreases the efficacy of opioids over time, but also puts individuals at risk of fatal overdoses. Therefore, it is essential to identify strategies to reduce opioid tolerance in those that use these agents. The gut microbiome has been found to play a critical role in opioid tolerance, with opioids causing dysbiosis of the gut, and changes in the gut microbiome impacting opioid tolerance. These changes in turn have a detrimental effect on the gut microbiome, creating a positive feedback cycle. We review the bidirectional relationship between the gut microbiome and opioid tolerance, discuss the role of modulation of the gut microbiome as a potential therapeutic option in opioid-induced gut dysbiosis, and suggest opportunities for further research and clinical interventions.

A cohort-based study of host gene expression: tumor suppressor and innate immune/inflammatory pathways associated with the HIV reservoir size

The major barrier to an HIV cure is the HIV reservoir: latently-infected cells that persist despite effective antiretroviral therapy (ART). There have been few cohort-based studies evaluating host genomic or transcriptomic predictors of the HIV reservoir. We performed host RNA sequencing and HIV reservoir quantification (total DNA [tDNA], unspliced RNA [usRNA], intact DNA) from peripheral CD4+ T cells from 191 ART-suppressed people with HIV (PWH). After adjusting for nadir CD4+ count, timing of ART initiation, and genetic ancestry, we identified two host genes for which higher expression was significantly associated with smaller total DNA viral reservoir size, P3H3 and NBL1, both known tumor suppressor genes. We then identified 17 host genes for which lower expression was associated with higher residual transcription (HIV usRNA). These included novel associations with membrane channel (KCNJ2, GJB2), inflammasome (IL1A, CSF3, TNFAIP5, TNFAIP6, TNFAIP9, CXCL3, CXCL10), and innate immunity (TLR7) genes (FDR-adjusted q<0.05). Gene set enrichment analyses further identified significant associations of HIV usRNA with TLR4/microbial translocation (q = 0.006), IL-1/NRLP3 inflammasome (q = 0.008), and IL-10 (q = 0.037) signaling. Protein validation assays using ELISA and multiplex cytokine assays supported these observed inverse host gene correlations, with P3H3, IL-10, and TNF-α protein associations achieving statistical significance (p<0.05). Plasma IL-10 was also significantly inversely associated with HIV DNA (p = 0.016). HIV intact DNA was not associated with differential host gene expression, although this may have been due to a large number of undetectable values in our study. To our knowledge, this is the largest host transcriptomic study of the HIV reservoir. Our findings suggest that host gene expression may vary in response to the transcriptionally active reservoir and that changes in cellular proliferation genes may influence the size of the HIV reservoir. These findings add important data to the limited host genetic HIV reservoir studies to date.

Influence of HIV infection on cognition and overall intelligence in HIV-infected individuals: advances and perspectives

It is now well understood that HIV-positive individuals, even those under effective ART, tend to develop a spectrum of cognitive, motor, and/or mood conditions which are contemporarily referred to as HIV-associated neurocognitive disorder (HAND), and which is directly related to HIV-1 infection and HIV-1 replication in the central nervous system (CNS). As HAND is known to induce difficulties associated with attention, concentration, and memory, it is thus legitimate and pertinent to speculate upon the possibility that HIV infection may well influence human cognition and intelligence. We therefore propose herein to review the concept of intelligence, the concept of cells of intelligence, the influence of HIV on these particular cells, and the evidence pointing to differences in observed intelligence quotient (IQ) scores between HIV-positive and HIV-negative individuals. Additionally, cumulative research evidence continues to draw attention to the influence of the gut on human intelligence. Up to now, although it is known that HIV infection profoundly alters both the composition and diversity of the gut microbiota and the structural integrity of the gut, the influence of the gut on intelligence in the context of HIV infection remains poorly described. As such, we also provide herein a review of the different ways in which HIV may influence human intelligence via the gut-brain axis. Finally, we provide a discourse on perspectives related to HIV and human intelligence which may assist in generating more robust evidence with respect to this issue in future studies. Our aim is to provide insightful knowledge for the identification of novel areas of investigation, in order to reveal and explain some of the enigmas related to HIV infection.

Combined effects of loneliness and inflammation on depression in people with HIV

OBJECTIVE

Loneliness is prevalent in people with HIV (PWH) and associated with adverse health-related consequences, including depression. Chronic inflammation has been linked to depression in PWH, though its association with loneliness is less well established. Simultaneous examination of inflammation, loneliness and depression is needed to clarify these relationships. This study investigated the relationship between loneliness and inflammation, and the effects of loneliness and inflammation on depression in PWH.

METHODS

82 PWH who were on suppressive ART (mean age [SD] = 53.2 [9.0]) completed the UCLA Loneliness Scale-Version 3 and the Center for Epidemiologic Studies Depression Scale as part of a comprehensive evaluation. Biomarkers of systemic inflammation (CRP, IL-6, CCL2/MCP-1, sCD14) and coagulation (D-dimer) were measured in blood using commercial immunoassays.

RESULTS

Multivariable linear regression analyses revealed that higher D-dimer, CCL2/MCP-1, and sCD14 were significant predictors of loneliness (ps < .05) while accounting for relevant covariates. Stepwise multiple linear regression models that included loneliness, biomarkers, and their interactions as predictors of depressive symptoms revealed significant main effects of loneliness and CCL2/MCP-1 levels (ps < .05), and a significant loneliness by D-dimer interaction (p < .05) whereby higher D-dimer was associated with increased depressive symptoms only at higher levels of loneliness.

CONCLUSIONS

Increased coagulation activity is associated with loneliness, and in the context of loneliness, may increase risk for depression. Increased inflammation was associated with depression suggesting potentially dissociable underlying biological processes. To the extent that these processes are modifiable, such findings could have important implications in the treatment of loneliness and depression in PWH.

Severe intestinal barrier damage in HIV-infected immunological non-responders

The intestinal epithelial barrier plays an important role during human immunodeficiency virus (HIV) disease progression. However, the extent to which the intestinal epithelial barrier is damaged in immunological non-responders (INRs) and immunological responders (IRs) is largely unknown. In this study, we investigated and compared the levels of intestinal gland damage and related molecules, including the tight junction protein claudin-1, apoptosis marker caspase-3, HIV DNA, CD4+ T cell count, and inflammation marker tumor necrosis factor-α (TNF-α) among the IRs (n = 10), INRs (n = 8), and healthy controls (HCs, n = 7). Intestinal damage was not completely restored in both INRs and IRs and was more serious in INRs than that in IRs. Moreover, intestinal damage was positively correlated with HIV DNA levels and negatively correlated with CD4+ T cell counts. These results provide insight into understanding the characteristics of intestinal epithelial barrier damage between IRs and INRs.

Effect of high dose vitamin D3 on the HIV-1 reservoir: A pilot randomised controlled trial

Introduction

Antiretroviral therapy for people living with HIV-1 must be taken lifelong due to the persistence of latent virus in long-lived and proliferating CD4+ T cells. Vitamin D3 is a steroidal gene transcription regulator which exerts diverse effects on immune and epithelial cells including reductions in CD4+ T cell proliferation and improvement in gut barrier integrity. We hypothesised that a high dose of vitamin D3 would reduce the size of the HIV-1 reservoir by reducing CD4+ T cell proliferation.

Methods

We performed a randomised placebo-controlled trial evaluating the effect of 24 weeks of vitamin D3 (10,000 international units per day) on the HIV-1 reservoir and immunologic parameters in 30 adults on antiretroviral therapy; participants were followed for 12 weeks post-treatment. The primary endpoint was the effect on total HIV-1 DNA at week 24. Parameters were assessed using mixed-effects models.

Results

We found no effect of vitamin D3 on the change in total HIV-1 DNA from week 0 to week 24 relative to placebo. There were also no changes in integrated HIV-1 DNA, 2-long-terminal repeat (2-LTR) circles or cell-associated HIV-1 RNA. Vitamin D3 induced a significant increase in the proportion of central memory CD4+ and CD8+ T cells, a reduction in the proportion of senescent CD8+ T cells and a reduction in the natural killer cell frequency at all time points including week 36, 12 weeks after the study drug cessation. At week 36, there was a significant reduction in total HIV-1 DNA relative to placebo and persistently elevated 25-hydroxyvitamin D levels. No significant safety issues were identified.

Conclusions

Vitamin D3 administration had a significant impact on the T cell differentiation but overall effects on the HIV-1 reservoir were limited and a reduction in HIV-1 DNA was only seen following cessation of the study drug. Additional studies are required to determine whether the dose and duration of vitamin D3 can be optimised to promote a continued depletion of the HIV-1 reservoir over time.

Trial registration

ClinicalTrials.gov NCT03426592.

Comparative polar and lipid plasma metabolomics differentiate KSHV infection and disease states

BACKGROUND

Kaposi sarcoma (KS) is a neoplastic disease etiologically associated with infection by the Kaposi sarcoma-associated herpesvirus (KSHV). KS manifests primarily as cutaneous lesions in individuals due to either age (classical KS), HIV infection (epidemic KS), or tissue rejection preventatives in transplantation (iatrogenic KS) but can also occur in individuals, predominantly in sub-Saharan Africa (SSA), lacking any obvious immune suppression (endemic KS). The high endemicity of KSHV and human immunodeficiency virus-1 (HIV) co-infection in Africa results in KS being one of the top 5 cancers there. As with most viral cancers, infection with KSHV alone is insufficient to induce tumorigenesis. Indeed, KSHV infection of primary human endothelial cell cultures, even at high levels, is rarely associated with long-term culture, transformation, or growth deregulation, yet infection in vivo is sustained for life. Investigations of immune mediators that distinguish KSHV infection, KSHV/HIV co-infection, and symptomatic KS disease have yet to reveal consistent correlates of protection against or progression to KS. In addition to viral infection, it is plausible that pathogenesis also requires an immunological and metabolic environment permissive to the abnormal endothelial cell growth evident in KS tumors. In this study, we explored whether plasma metabolomes could differentiate asymptomatic KSHV-infected individuals with or without HIV co-infection and symptomatic KS from each other.

METHODS

To investigate how metabolic changes may correlate with co-infections and tumorigenesis, plasma samples derived from KSHV seropositive sub-Saharan African subjects in three groups, (A) asymptomatic (lacking neoplastic disease) with KSHV infection only, (B) asymptomatic co-infected with KSHV and HIV, and (C) symptomatic with clinically diagnosed KS, were subjected to analysis of lipid and polar metabolite profiles RESULTS: Polar and nonpolar plasma metabolic differentials were evident in both comparisons. Integration of the metabolic findings with our previously reported KS transcriptomics data suggests dysregulation of amino acid/urea cycle and purine metabolic pathways, in concert with viral infection in KS disease progression.

CONCLUSIONS

This study is, to our knowledge, the first to report human plasma metabolic differentials between in vivo KSHV infection and co-infection with HIV, as well as differentials between co-infection and epidemic KS.

Therapeutically targeting the consequences of HIV-1-associated gastrointestinal dysbiosis: Implications for neurocognitive and affective alterations

Approximately 50 % of the individuals living with human immunodeficiency virus type 1 (HIV-1) are plagued by debilitating neurocognitive impairments (NCI) and/or affective alterations. Sizeable alterations in the composition of the gut microbiome, or gastrointestinal dysbiosis, may underlie, at least in part, the NCI, apathy, and/or depression observed in this population. Herein, two interrelated aims will be critically addressed, including: 1) the evidence for, and functional implications of, gastrointestinal microbiome dysbiosis in HIV-1 seropositive individuals; and 2) the potential for therapeutically targeting the consequences of this dysbiosis for the treatment of HIV-1-associated NCI and affective alterations. First, gastrointestinal microbiome dysbiosis in HIV-1 seropositive individuals is characterized by decreased alpha (α) diversity, a decreased relative abundance of bacterial species belonging to the Bacteroidetes phylum, and geographic-specific alterations in Bacillota (formerly Firmicutes) spp. Fundamentally, changes in the relative abundance of Bacteroidetes and Bacillota spp. may underlie, at least in part, the deficits in γ-aminobutyric acid and serotonin neurotransmission, as well as prominent synaptodendritic dysfunction, observed in this population. Second, there is compelling evidence for the therapeutic utility of targeting synaptodendritic dysfunction as a method to enhance neurocognitive function and improve motivational dysregulation in HIV-1. Further research is needed to determine whether the therapeutics enhancing synaptic efficacy exert their effects by altering the gut microbiome. Taken together, understanding gastrointestinal microbiome dysbiosis resulting from chronic HIV-1 viral protein exposure may afford insight into the mechanisms underlying HIV-1-associated neurocognitive and/or affective alterations; mechanisms which can be subsequently targeted via novel therapeutics.

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.

Physical Activity as an Adjunct Treatment for People Living with HIV?

This review evaluates physical activity as a candidate for an adjunct treatment, in conjunction with antiretroviral therapy (ART), for people living with HIV (PLWH). Evidence is summarized that chronic, non-resolving inflammation (a principal feature of immune system dysfunction) and a dysfunctional state of the gut environment are key factors in HIV infection that persist despite treatment with ART. In addition, evidence is summarized that regular physical activity may restore normal function of both the immune system and the gut environment and may thereby ameliorate symptoms and non-resolving inflammation-associated comorbidities that burden PLWH. Physicians who care for PLWH could thus consider incorporating physical activity into treatment plans to complement ART. It is also discussed that different types of physical activity can have different effects on the gut environment and immune function, and that future research should establish more specific criteria for the design of exercise regimens tailored to PLWH.

Biomarkers of central and peripheral inflammation mediate the association between HIV and depressive symptoms

People living with HIV are at increased risk for depression, though the underlying mechanisms for this are unclear. In the general population, depression is associated with peripheral and central inflammation. Given this, and since HIV infection elicits inflammation, we hypothesised that peripheral and central inflammatory biomarkers would at least partly mediate the association between HIV and depressive symptoms. People living with HIV (n = 125) and without HIV (n = 79) from the COmorBidity in Relation to AIDS (COBRA) cohort were included in this study. Participants living with and without HIV had similar baseline characteristics. All participants living with HIV were on antiretroviral therapy and were virally suppressed. Plasma, CSF, and brain MR spectroscopy (MRS) biomarkers were measured. Using logistic regression models adjusted for sociodemographic factors, we found that participants with HIV were more likely to have Any Depressive Symptoms (Patient Health Questionnaire [PHQ-9] score >4) (odds ratio [95% confidence interval] 3.27 [1.46, 8.09]). We then sequentially adjusted the models for each biomarker separately to determine the mediating role of each biomarker, with a >10% reduction in OR considered as evidence of potential mediation. Of the biomarkers analysed, MIG (-15.0%) and TNF-α (-11.4%) in plasma and MIP1-α (-21.0%) and IL-6 (-18.0%) in CSF mediated the association between HIV and depressive symptoms in this sample. None of the other soluble or neuroimaging biomarkers substantially mediated this association. Our findings suggest that certain biomarkers of central and peripheral inflammation may at least partly mediate the relationship between HIV and depressive symptoms.

The human microbiome and gut-liver axis in people living with HIV

PURPOSE OF REVIEW

Chronic liver disease is a major cause of morbidity and mortality amongst people living with HIV (PLWH). Emerging data suggests that gut microbial translocation may play a role in driving and modulating liver disease, a bi-directional relationship termed the gut-liver axis. While it is recognized that PLWH have a high degree of dysbiosis and gut microbial translocation, little is known about the gut-liver axis in PLWH.

RECENT FINDINGS

Recent studies have shown that microbial translocation can directly lead to hepatic inflammation, and have linked gut microbial signatures, dysbiosis, and translocation to liver disease in PLWH. Additionally, multiple trials have explored interventions targeting the microbiome in PLWH. Emerging research supports the interaction between the gut microbiome and liver disease in PLWH. This offers new opportunities to expand our understanding of the pathophysiology of liver disease in this population, as well as to explore possible clinical interventions.

The Imbalance Between Intestinal Th17 and Treg Cells Is Associated with an Incomplete Immune Reconstitution During Long-Term Antiretroviral Therapy in Patients with HIV

Studies assessing the gut mucosal immune balance in HIV-infected patients using intestinal samples are scarce. In this study, we used intestinal mucosal specimens from the ileocecal region of seven immunological nonresponders (INRs), nine immunological responders (IRs), and six HIV-negative controls. We investigated T helper 17 (Th17) and T regulatory (Treg) cell counts and their ratio, zonula occludens-1 (ZO-1), intestinal fatty acid-binding protein (I-FABP), tumor necrosis factor-α, CD4+ T cell counts, HIV DNA, and cell-associated HIV RNA. The results showed that INRs had lower Th17 and higher Treg cell counts than IR, resulting in a significant difference in the Th17/Treg ratio between IRs and INRs. In addition, INRs had lower ZO-1 and higher I-FABP levels than IRs. The Th17/Treg ratio was positively associated with ZO-1 and negatively associated with I-FABP levels. There was a positive correlation between Th17/Treg ratio and CD4+ T cell counts and a negative correlation between the Th17/Treg ratio and HIV DNA in the intestine. Our study suggests that the imbalance of Th17/Treg in the intestine is a characteristic of incomplete immune reconstitution to antiretroviral therapy and is associated with intestinal damage.

Impact of the first-line antiretroviral therapy on soluble markers of inflammation in cohort of human immunodeficiency virus type 1 in Moroccan patients: a prospective study

Chronic inflammation and immune activation are a hallmark of HIV-1 infection. In this study, we assessed inflammation biomarkers in a cohort of people living with HIV-1 (PLWH) before and after long-term suppressive combined antiretroviral therapy (cART). A single-center prospective cohort study was conducted to assess inflammatory biomarkers in 86 cART-naive PLWH and after receiving suppressive cART and 50 uninfected controls. Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and soluble CD14 (sCD14) were measured using enzyme-linked immunosorbent assay (ELISA). No significant difference was found in IL-6 levels between cART-naïve PLWH and controls (p = 0.753). In contrast, TNF-α level showed a significant difference between cART naïve-PLWH and controls (p = 0.019). Interestingly, IL-6 and TNF-α levels were significantly decreased in PLWH after cART (p < 0.0001). The sCD14 showed no significant difference between cART-naïve patients and controls (p = 0.839) and similar levels were observed in pre- and post-treatment (p = 0.719). Our results highlight the critical importance of early treatment to reduce inflammation and its consequences during HIV infection.

Long COVID in people living with HIV

PURPOSE OF REVIEW

It is now recognized that SARS-CoV-2 infection can have a long-term impact on health. This review summarizes the current state of knowledge regarding Long COVID in people living with HIV (PLWH).

RECENT FINDINGS

PLWH may be at elevated risk of experiencing Long COVID. Although the mechanisms contributing to Long COVID are incompletely understood, there are several demographic and clinical factors that might make PLWH vulnerable to developing Long COVID.

SUMMARY

PLWH should be aware that new or worsening symptoms following SARS-CoV-2 infection might represent Long COVID. HIV providers should be aware of this clinical entity and be mindful that their patients recovering from SARS-CoV-2 infection may be at higher risk.

Role of the gut-brain axis in HIV and drug abuse-mediated neuroinflammation

Drug abuse and related disorders are a global public health crisis affecting millions, but to date, limited treatment options are available. Abused drugs include but are not limited to opioids, cocaine, nicotine, methamphetamine, and alcohol. Drug abuse and human immunodeficiency virus-1/acquired immune deficiency syndrome (HIV-1/AIDS) are inextricably linked. Extensive research has been done to understand the effect of prolonged drug use on neuronal signaling networks and gut microbiota. Recently, there has been rising interest in exploring the interactions between the central nervous system and the gut microbiome. This review summarizes the existing research that points toward the potential role of the gut microbiome in the pathogenesis of HIV-1-linked drug abuse and subsequent neuroinflammation and neurodegenerative disorders. Preclinical data about gut dysbiosis as a consequence of drug abuse in the context of HIV-1 has been discussed in detail, along with its implications in various neurodegenerative disorders. Understanding this interplay will help elucidate the etiology and progression of drug abuse-induced neurodegenerative disorders. This will consequently be beneficial in developing possible interventions and therapeutic options for these drug abuse-related disorders.

In-depth virological and immunological characterization of HIV-1 cure after CCR5Δ32/Δ32 allogeneic hematopoietic stem cell transplantation

Despite scientific evidence originating from two patients published to date that CCR5Δ32/Δ32 hematopoietic stem cell transplantation (HSCT) can cure human immunodeficiency virus type 1 (HIV-1), the knowledge of immunological and virological correlates of cure is limited. Here we characterize a case of long-term HIV-1 remission of a 53-year-old male who was carefully monitored for more than 9 years after allogeneic CCR5Δ32/Δ32 HSCT performed for acute myeloid leukemia. Despite sporadic traces of HIV-1 DNA detected by droplet digital PCR and in situ hybridization assays in peripheral T cell subsets and tissue-derived samples, repeated ex vivo quantitative and in vivo outgrowth assays in humanized mice did not reveal replication-competent virus. Low levels of immune activation and waning HIV-1-specific humoral and cellular immune responses indicated a lack of ongoing antigen production. Four years after analytical treatment interruption, the absence of a viral rebound and the lack of immunological correlates of HIV-1 antigen persistence are strong evidence for HIV-1 cure after CCR5Δ32/Δ32 HSCT.

The Evaluation of Intestinal Permeability in Preeclamptic Pregnancy

BACKGROUND

Zonulin is a physiological protein that regulates the tight connections and permeability of the intestine, serving as a biomarker for impaired intestinal permeability.

OBJECTIVE

The aim of this study was to examine zonulin levels in preeclampsia, to investigate its associations with the cellular immune response marker soluble interleukin-2 receptor (sIL-2R) and exogenous antigen load marker lipopolysaccharide binding protein (LBP) and to evaluate the implications of these findings in the etiopathogenesis of preeclampsia.

METHODS

We designed a cross-sectional case-control study and enrolled 22 pregnant women with preeclampsia and 22 healthy pregnant controls. Plasma zonulin levels were determined by ELISA. Serum sIL-2R and LBP levels were assessed by chemiluminescent immunometric methods.

RESULTS

Women with preeclampsia had lower levels of plasma zonulin and serum LBP than normotensive healthy controls (p<0,05). The difference in serum sIL-2R levels was not significant (p: 0,751). There was a negative correlation between plasma zonulin and serum urea (r: -0.319, p: 0.035) and a positive correlation between serum sIL-2R and ALT (r: 0,335, p: 0,026) and AST (r: 0,319, p: 0,035).

CONCLUSION

We found that zonulin and LBP, but not sIL-2R, levels were significantly lower in pregnant women with preeclampsia as compared with healthy pregnant controls. Reduced intestinal permeability in preeclampsia might be associated with impaired immune system functions or a lower fat mass and malnutrition. Further studies are needed to elucidate the exact pathogenetic role of intestinal permeability in preeclampsia.

Chronic immune activation and gut barrier dysfunction is associated with neuroinflammation in ART-suppressed SIV+ rhesus macaques

HIV-associated neurocognitive disorders (HAND) affect ~40% of virally suppressed people with HIV (PWH), however, the precise viral dependent and independent changes to the brain are unclear. Here we characterized the CNS reservoir and immune environment of SIV-infected (SIV+) rhesus macaques during acute (n = 4), chronic (n = 12) or ART-suppressed SIV infection (n = 11). Multiplex immunofluorescence for markers of SIV infection (vRNA/vDNA) and immune activation was performed on frontal cortex and matched colon tissue. SIV+ animals contained detectable viral DNA+ cells that were not reduced in the frontal cortex or the gut by ART, supporting the presence of a stable viral reservoir in these compartments. SIV+ animals had impaired blood brain barrier (BBB) integrity and heightened levels of astrocytes or myeloid cells expressing antiviral, anti-inflammatory or oxidative stress markers which were not abrogated by ART. Neuroinflammation and BBB dysfunction correlated with measures of viremia and immune activation in the gut. Furthermore, SIV-uninfected animals with experimentally induced gut damage and colitis showed a similar immune activation profile in the frontal cortex to those of SIV-infected animals, supporting the role of chronic gut damage as an independent source of neuroinflammation. Together, these findings implicate gut-associated immune activation/damage as a significant contributor to neuroinflammation in ART-suppressed HIV/SIV infection which may drive HAND pathogenesis.

The microbiota as a modulator of mucosal inflammation and HIV/HPV pathogenesis: From association to causation

Although the microbiota has largely been associated with the pathogenesis of viral infections, most studies using omics techniques are correlational and hypothesis-generating. The mechanisms affecting the immune responses to viral infections are still being fully understood. Here we focus on the two most important sexually transmitted persistent viruses, HPV and HIV. Sophisticated omics techniques are boosting our ability to understand microbiota-pathogen-host interactions from a functional perspective by surveying the host and bacterial protein and metabolite production using systems biology approaches. However, while these strategies have allowed describing interaction networks to identify potential novel microbiota-associated biomarkers or therapeutic targets to prevent or treat infectious diseases, the analyses are typically based on highly dimensional datasets -thousands of features in small cohorts of patients-. As a result, we are far from getting to their clinical use. Here we provide a broad overview of how the microbiota influences the immune responses to HIV and HPV disease. Furthermore, we highlight experimental approaches to understand better the microbiota-host-virus interactions that might increase our potential to identify biomarkers and therapeutic agents with clinical applications.

Differences in expression of tumor suppressor, innate immune, inflammasome, and potassium/gap junction channel host genes significantly predict viral reservoir size during treated HIV infection

The major barrier to an HIV cure is the persistence of infected cells that evade host immune surveillance despite effective antiretroviral therapy (ART). Most prior host genetic HIV studies have focused on identifying DNA polymorphisms (e.g., CCR5Δ32 , MHC class I alleles) associated with viral load among untreated "elite controllers" (~1% of HIV+ individuals who are able to control virus without ART). However, there have been few studies evaluating host genetic predictors of viral control for the majority of people living with HIV (PLWH) on ART. We performed host RNA sequencing and HIV reservoir quantification (total DNA, unspliced RNA, intact DNA) from peripheral CD4+ T cells from 191 HIV+ ART-suppressed non-controllers. Multivariate models included covariates for timing of ART initiation, nadir CD4+ count, age, sex, and ancestry. Lower HIV total DNA (an estimate of the total reservoir) was associated with upregulation of tumor suppressor genes NBL1 (q=0.012) and P3H3 (q=0.012). Higher HIV unspliced RNA (an estimate of residual HIV transcription) was associated with downregulation of several host genes involving inflammasome ( IL1A, CSF3, TNFAIP5, TNFAIP6, TNFAIP9 , CXCL3, CXCL10 ) and innate immune ( TLR7 ) signaling, as well as novel associations with potassium ( KCNJ2 ) and gap junction ( GJB2 ) channels, all q<0.05. Gene set enrichment analyses identified significant associations with TLR4/microbial translocation (q=0.006), IL-1β/NRLP3 inflammasome (q=0.008), and IL-10 (q=0.037) signaling. HIV intact DNA (an estimate of the "replication-competent" reservoir) demonstrated trends with thrombin degradation ( PLGLB1 ) and glucose metabolism ( AGL ) genes, but data were (HIV intact DNA detected in only 42% of participants). Our findings demonstrate that among treated PLWH, that inflammation, innate immune responses, bacterial translocation, and tumor suppression/cell proliferation host signaling play a key role in the maintenance of the HIV reservoir during ART. Further data are needed to validate these findings, including functional genomic studies, and expanded epidemiologic studies in female, non-European cohorts.

Author Summary

Although lifelong HIV antiretroviral therapy (ART) suppresses virus, the major barrier to an HIV cure is the persistence of infected cells that evade host immune surveillance despite effective ART, "the HIV reservoir." HIV eradication strategies have focused on eliminating residual virus to allow for HIV remission, but HIV cure trials to date have thus far failed to show a clinically meaningful reduction in the HIV reservoir. There is an urgent need for a better understanding of the host-viral dynamics during ART suppression to identify potential novel therapeutic targets for HIV cure. This is the first epidemiologic host gene expression study to demonstrate a significant link between HIV reservoir size and several well-known immunologic pathways (e.g., IL-1β, TLR7, TNF-α signaling pathways), as well as novel associations with potassium and gap junction channels (Kir2.1, connexin 26). Further data are needed to validate these findings, including functional genomic studies and expanded epidemiologic studies in female, non-European cohorts.

Cellular and molecular insights into incomplete immune recovery in HIV/AIDS patients

Highly active antiretroviral therapy (ART) can effectively inhibit virus replication and restore immune function in most people living with human immunodeficiency virus (HIV). However, an important proportion of patients fail to achieve a satisfactory increase in CD4⁺ T cell counts. This state is called incomplete immune reconstitution or immunological nonresponse (INR). Patients with INR have an increased risk of clinical progression and higher rates of mortality. Despite widespread attention to INR, the precise mechanisms remain unclear. In this review, we will discuss the alterations in the quantity and quality of CD4⁺ T as well as multiple immunocytes, changes in soluble molecules and cytokines, and their relationship with INR, aimed to provide cellular and molecular insights into incomplete immune reconstitution.

Hepatitis B immunization data of patients living with HIV/AIDS: a multi-centre study

OBJECTIVES

Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are the two leading viruses that cause the greatest number of virus-related morbidities in the world. HIV/HBV coinfection is correlated with high morbidity and mortality. For this particular reason hepatitis B vaccination is crucial for people living with HIV.

METHODS

Patients who are being followed-up for HIV/AIDS and who have received a hepatitis B vaccine in 4 HIV clinics over a 5-year time period have been studied. Our multi-centered, retrospective, cross-sectional and observational study investigates factors that affect hepatitis B vaccination immune response of individuals living with HIV. The patients have been studied for the parameters such as age, sex, CD4 count at the time of diagnosis or vaccination, HIV-RNA levels, comorbidities, vaccine dosage, success of immunization after vaccination, and the demographics of the patients who have and have not developed immunity.

RESULTS

Of 645 patients that are being followed-up in our clinics, 158 received hepatitis B vaccine; 39 of these 158 patients have been excluded from the study because they did not fulfil the inclusion criteria. Finally, 119 patients were evaluated in the study, 17 of the patients (14.3%) were females and 102 (85.7%) were males. The median age was 41.11 ± 10.09 (min-max: 18-75). Twenty-three of the patients (19.3%) were at the stage of AIDS during diagnosis while 80.7% were at the stage of HIV infection. Ninety-one of the patients (76.5%) have been administered a single dose hepatitis B vaccine on the standard 0, 1st, 6th month vaccination schedule, whereas 23.5% were administered a double dose on the same vaccination schedule. When further evaluated to find whether the patient was able to develop sufficient immunity (anti-HBs ≥ 10), it was found that the immune response was statistically significantly higher in the patients whose CD4 count was greater than 200 at the time of the first diagnosis and vaccination (p = 0.05 and p = 0.001, respectively). The patients have also been evaluated according to the number of doses they received (1 vs. 2). The immune response of the patients who received two doses was statistically significantly higher (p = 0.041).

CONCLUSION

We can conclude that in the patients with CD4 count less than 200 at the time of their diagnosis and vaccination a high dose recombinant hepatitis B vaccine should definitely be administered as the normal dose and higher dose have similar side effect profiles and the higher dose provides greater immunity.

Non-Human Primate Models of HIV Brain Infection and Cognitive Disorders

Human Immunodeficiency virus (HIV)-associated neurocognitive disorders are a major burden for people living with HIV whose viremia is stably suppressed with antiretroviral therapy. The pathogenesis of disease is likely multifaceted, with contributions from viral reservoirs including the brain, chronic and systemic inflammation, and traditional risk factors including drug use. Elucidating the effects of each element on disease pathogenesis is near impossible in human clinical or ex vivo studies, facilitating the need for robust and accurate non-human primate models. In this review, we describe the major non-human primate models of neuroHIV infection, their use to study the acute, chronic, and virally suppressed infection of the brain, and novel therapies targeting brain reservoirs and inflammation.

HIV and cardiovascular disease: the role of inflammation

PURPOSE OF REVIEW

HIV and antiretroviral therapy (ART) use are linked to an increased incidence of atherosclerotic cardiovascular disease (ASCVD). Immune activation persists in ART-treated people with HIV (PWH), and markers of inflammation (i.e. IL-6, C-reactive protein) predict mortality in this population. This review discusses underlying mechanisms that likely contribute to inflammation and the development of ASCVD in PWH.

RECENT FINDINGS

Persistent inflammation contributes to accelerated ASCVD in HIV and several new insights into the underlying immunologic mechanisms of chronic inflammation in PWH have been made (e.g. clonal haematopoiesis, trained immunity, lipidomics). We will also highlight potential pro-inflammatory mechanisms that may differ in vulnerable populations, including women, minorities and children.

SUMMARY

Mechanistic studies into the drivers of chronic inflammation in PWH are ongoing and may aid in tailoring effective therapeutic strategies that can reduce ASCVD risk in this population. Focus should also include factors that lead to persistent disparities in HIV care and comorbidities, including sex as a biological factor and social determinants of health. It remains unclear whether ASCVD progression in HIV is driven by unique mediators (HIV itself, ART, immunodeficiency), or if it is an accelerated version of disease progression seen in the general population.

Contribution of Innate Lymphoid Cells in Supplementing Cytokines Produced by CD4+ T Cells During Acute and Chronic SIV Infection of the Colon

HIV/SIV (simian immunodeficiency virus) infection leads to a loss of CD4+ T helper (Th) cells in number and function that begins during the acute phase and persists through the chronic phase of infection. In particular, there is a drastic decrease of Th17 and Th22 cells in the HIV/SIV-infected gastrointestinal (GI) tract as a source of interleukin (IL)-17 and IL-22. These cytokines are vital in the immune response to extracellular pathogens and maintenance of the GI tract. However, innate lymphoid cells (ILCs) are a source of IL-17 and IL-22 during the early stages of an immune response in mucosal tissue and remain vital cytokine producers when the immune response is persistent. Here, we wanted to determine whether ILCs are a source of IL-17 and IL-22 in the SIV-infected colon and could compensate for the loss of Th17 and Th22 cells. As a control, we evaluated the frequency and number of ILCs expressing interferon-gamma (IFNγ) and tumor necrosis factor-alpha (TNFα). We determined the frequency and number of cytokine expressing ILC subsets and T cell subsets within leukocytes from the colons of uninfected as well as acute and chronic SIV-infected colons without in vitro mitogenic stimulation. In the present study, we find that: (1) the frequency of IL-22, IFNγ, and TNFα but not IL-17 producing ILCs is increased in the acutely infected colon and remains high during the chronically infected colon relative to cytokine expressing ILCs in the uninfected colon, (2) ILCs are a significant source of IL-22, IFNγ, and TNFα but not IL-17 when CD4+ T lymphocytes in the gut lose their capacity to secrete these cytokines during SIV infection, and (3) the changes in the cytokines expressed by ILCs relative to CD4+ T cells in the infected colon were not due to increases in the frequency or number of ILCs in relation to T lymphocytes found in the tissue.

Effect of Antiretroviral Therapy on Neutrophil Oxidative Burst in Children

OBJECTIVE

To ascertain the effect of human immunodeficiency virus (HIV) infection, as well as, antiretroviral therapy (ART) on neutrophil oxidative burst in children.

METHODS

Fifty-five children living with HIV infection (30 receiving ART for ≥ 2 y, 25 treatment-naïve) and 30 healthy controls, aged 18 mo-18 y, were assessed for hemogram and neutrophil oxidative burst. The treatment-naïve children were followed up and the above tests were repeated after 6 mo of ART.

RESULTS

Mean (SD) serum MPO activity at 6 mo after ART [32.1 (± 19.9) U/L] was comparable to that at disease onset [17.2 (± 23.0) U/L], although it was significantly higher compared to that in children on ART ≥ 2 y [13.3 (± 15.8) U/L] and controls [12.1 (± 11.9) U/L]. Median fluorescence intensity (MFI) of unstimulated DHR was highest at 6 mo after ART and in the treatment-naïve group, which was significantly higher than in the controls, as well as, children receiving ART ≥ 2 y. Stimulation index was highest in the control group [442.4 (341.9-562.9)], which was comparable to that in children on ART ≥ 2 y [304.2 (153.2-664.8)], but was significantly higher than the treatment-naïve cohort [266.1 (148.2-339.4)] and children on ART for 6 mo [318.8 (154.9-395.6)].

CONCLUSION

A hyperinflammatory state caused by an increased serum myeloperoxidase enzyme activity and increased basal neutrophil oxidative burst was seen in untreated HIV infection and during initial 6 mo of ART. ART given for ≥ 2 y normalized the impaired neutrophilic phagocytic functions.

Altered Innate Immunity and Damaged Epithelial Integrity in Vaginal Microbial Dysbiosis

The role of neutrophils relative to vaginal dysbiosis is unclear. We hypothesize that bacterial vaginosis (BV)-associated bacteria may induce the activation and accumulation of mucosal neutrophils within the female reproductive tract (FRT), resulting in epithelial barrier damage. We collected endocervical cytobrushes from women with and without BV and assessed bacteria community type and frequency/functional phenotypes of neutrophils. We performed in vitro whole blood co-cultures with BV-associated bacteria and healthy vaginal commensals and assessed their impact on epithelial integrity using transepithelial electrical resistance. We demonstrated increased neutrophil frequency (p < 0.0001), activation (p < 0.0001), and prolonged lifespan (p < 0.0001) in the cytobrushes from women with non-Lactobacillus dominant (nLD) communities. Our in vitro co-cultures confirmed these results and identified significant barrier damage in the presence of neutrophils and G. vaginalis. Here, we demonstrate that BV-associated bacteria induce neutrophil activation and increase lifespan, potentially causing accumulation in the FRT and epithelial barrier damage.

Human Blood Bacteriome: Eubiotic and Dysbiotic States in Health and Diseases

The human gut microbiome is acknowledged as being associated with homeostasis and the pathogenesis of several diseases. Conventional culture techniques are limited in that they cannot culture the commensals; however, next-generation sequencing has facilitated the discovery of the diverse and delicate microbial relationship in body sites and blood. Increasing evidence regarding the blood microbiome has revolutionized the concept of sterility and germ theory in circulation. Among the types of microbial communities in the blood, bacteriomes associated with many health conditions have been thoroughly investigated. Blood bacterial profiles in healthy subjects are identified as the eubiotic blood bacteriome, whereas the dysbiotic blood bacteriome represents the change in bacterial characteristics in subjects with diseases showing deviations from the eubiotic profiles. The blood bacterial characteristics in each study are heterogeneous; thus, the association between eubiotic and dysbiotic blood bacteriomes and health and disease is still debatable. Thereby, this review aims to summarize and discuss the evidence concerning eubiotic and dysbiotic blood bacteriomes characterized by next-generation sequencing in human studies. Knowledge pertaining to the blood bacteriome will transform the concepts around health and disease in humans, facilitating clinical implementation in the near future.

HIV Symptom Clusters are Similar Using the Dimensions of Symptom Occurrence and Distress

CONTEXT

People living with HIV infection (PLWH) in the United States continue to experience a high symptom burden despite improvements in antiretroviral therapy.

OBJECTIVES

The purpose of this study was to determine if the number and types of symptom clusters differed based on whether symptom occurrence rates or distress ratings were used to create the clusters.

METHODS

Data from 2,000 patients with complete symptom occurrence rates and distress scores on the 20-item HIV Symptom Index from their first ambulatory clinic visit at one of six national HIV centers of excellence in the Center for AIDS Research Network of Integrated Clinical Systems were used in these analyses. Exploratory factor analysis was used to create the symptom clusters.

RESULTS

The same four symptom clusters (i.e., gastrointestinal, psychological, pain, body image) were identified using occurrence rates and distress ratings. For both dimensions of the symptom experience, the psychological, pain, and body image clusters each had the same symptoms. For the gastrointestinal cluster, four symptoms loaded on the occurrence dimension and six symptoms loaded on the distress dimension.

CONCLUSION

The number and types of symptom clusters were relatively similar across the occurrence and distress dimensions of the symptom experience. Symptom clusters in PLWH may provide insights into the development of targeted interventions for multiple co-occurring symptoms.

Periods of Homelessness Linked to Higher VACS Index Among HIV-Positive People Who Use Drugs

We sought to evaluate the impact of homelessness on HIV disease progression among people who use unregulated drugs (PWUD) living with HIV and test if this association was mediated by adherence to antiretroviral therapy (ART). We applied general linear mixed-effects modeling to estimate the longitudinal relationship between homelessness and the Veterans Aging Cohort Study (VACS) Index, a validated measure of HIV disease progression that predicts all-cause mortality, among a prospective cohort of PWUD. In a longitudinal model adjusted for ART adherence, homelessness was significantly associated with increased VACS Index scores and 16% of the association was mediated by ART adherence. These findings indicate that homelessness was a significant risk factor for HIV disease progression and this association was marginally mediated by ART adherence. Future studies are needed to quantify the other mechanisms (e.g., food insecurity, mental health) by which homelessness increases mortality risk among PWUD living with HIV.