Relationship of Diet to Gut Microbiota and Inflammatory Biomarkers in People with HIV

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.

Therapeutic microbiome modulation: new frontiers in HIV treatment

PURPOSE OF REVIEW

Dysbiosis may be a key driver of systemic inflammation, which increases the risk of non-AIDS events in people living with HIV (PLWH). Modulation of the microbiome to reverse this dysbiosis may be a novel approach to decrease inflammation and therefore morbidity and mortality in PLWH.

RECENT FINDINGS

Fecal microbiota transplantation (FMT), probiotics, prebiotics, synbiotics, postbiotics, and dietary modifications have the potential to modulate the microbiome. These interventions have been well tolerated in clinical trials to date. However, these interventions have not resulted in consistent or lasting changes to the microbiome or consistent changes in biomarkers of intestinal permeability, microbial translocation, inflammation, immune activation, or CD4+ T cell counts. Sustained engraftment may require prebiotics and/or dietary modifications added to either probiotics or FMT.

SUMMARY

Adequately powered randomized controlled trials are needed to elucidate whether microbiome modulation can be achieved and impact systemic inflammation in PLWH.

The dietary inflammatory index and cardiometabolic parameters in US firefighters

Introduction

Dietary choices play a crucial role in influencing systemic inflammation and the eventual development of cardiovascular diseases (CVD). The Dietary Inflammatory Index (DII®) is a novel tool designed to assess the inflammatory potential of one's diet. Firefighting, which is characterized by high-stress environments and elevated CVD risk, represents an interesting context for exploring the dietary inflammatory-CVD connection.

Aim

This study aims to investigate the associations between Energy-adjusted Dietary Inflammatory Index (E-DII™) scores and cardiometabolic risk parameters among US firefighters.

Methods

The study analyzed 413 participants from the Indianapolis Fire Department who took part in a Federal Emergency Management Agency (FEMA)-sponsored Mediterranean diet intervention trial. Thorough medical evaluations, encompassing physical examinations, standard laboratory tests, resting electrocardiograms, and submaximal treadmill exercise testing, were carried out. Participants also completed a detailed food frequency questionnaire to evaluate dietary patterns, and E-DII scores were subsequently computed based on the gathered information.

Results

Participants had a mean body mass index (BMI) of 30.0 ± 4.5 kg/m2 and an average body fat percentage of 28.1 ± 6.6%. Regression analyses, adjusted for sex, BMI, maximal oxygen consumption (VO2 max), max metabolic equivalents (METS), age, and body fat percentage, revealed significant associations between high vs. low E-DII scores and total cholesterol (β = 10.37, p = 0.04). When comparing low Vs median E-DII scores there is an increase in glucose (β = 0.91, p = 0.72) and total cholesterol (β = 5.51, p = 0.26).

Conclusion

Our findings support an association between higher E-DII scores and increasing adiposity, as well as worse lipid profiles.

The interaction between Mediterranean diet and intestinal microbiome: relevance for preventive strategies against frailty in older individuals

Age-related changes in intestinal microbiome composition and function are increasingly recognized as pivotal in the pathophysiology of aging and are associated with the aging phenotype. Diet is a major determinant of gut-microbiota composition throughout the entire lifespan, and several of the benefits of a healthy diet in aging could be mediated by the microbiome. Mediterranean diet (MD) is a traditional dietary pattern regarded as the healthy diet paradigm, and a large number of studies have demonstrated its benefits in promoting healthy aging. MD has also a positive modulatory effect on intestinal microbiome, favoring bacterial taxa involved in the synthesis of several bioactive compounds, such as short-chain fatty acids (SCFAs), that counteract inflammation, anabolic resistance, and tissue degeneration. Intervention studies conducted in older populations have suggested that the individual response of older subjects to MD, in terms of reduction of frailty scores and amelioration of cognitive function, is significantly mediated by the gut-microbiota composition and functionality. In this context, the pathophysiology of intestinal microbiome in aging should be considered when designing MD-based interventions tailored to the needs of geriatric patients.

Gut Microbiome (Bacteria, Fungi, and Viruses) and HIV Infection: Revealing Novel Treatment Strategies

Plenty of research on microbial-viral interactions has revealed that some commensal microorganisms in the gut, including bacteria, fungi, and viruses, can resist or promote viral infection, whereas other microorganisms are involved in pathogenicity. Therefore, the balance between commensal microorganisms and human organisms is a key factor for determining infection and disease progression, and commensal microorganisms have become a hot research area in the medical field. In this review, the compositional characteristics of gut microbiota (bacteria, fungi, and viruses) during HIV infection are reviewed and changes in gut microbiota among different HIV-infected populations are described. Furthermore, the latest progress of potential microbial therapeutic methods, including a) probiotics, prebiotics, and synbiotics, b) fecal microbiota transplantation (FMT), c) phage therapy, and d) antifungal strategy, microbial enzyme inhibition, and dietary therapeutics, is analyzed based on gut bacteria, fungi, and viruses in the field of HIV infection. This study aims to provide a useful reference for developing novel strategies for the prevention and treatment of HIV infection based on commensal microorganisms.

Abnormal blood microbiota profiles are associated with inflammation and immune restoration in HIV/AIDS individuals

IMPORTANCE

The characteristics of blood microbiota in HIV-infected individuals and their relevance to disease progression are still unknown, despite alterations in gut microbiota diversity and composition in HIV-infected individuals. Here, we present evidence of increased blood microbiota diversity in HIV-infected individuals, which may result from gut microbiota translocation. Also, we identify a group of microbes, Porphyromonas gingivalis, Prevotella sp. CAG:5226, Eubacterium sp. CAG:251, Phascolarctobacterium succinatutens, Anaerobutyricum hallii, Prevotella sp. AM34-19LB, and Phocaeicola plebeius, which are linked to poor immunological recovery. This work provides a scientific foundation toward therapeutic strategies targeting blood microbiota for immune recovery of HIV infection.

Protective effect of Bifidobacterium longum BB536 against nausea caused by pirfenidone in a mouse model of pellagra

Pellagra is caused by abnormal intake and/or use of nicotinic acid and is known in part to be induced by the use of medications such as isoniazid or pirfenidone. We previously investigated atypical phenotypes of pellagra, such as nausea, using a mouse model of pellagra and found that gut microbiota play an important role in the development of these phenotypes. Here, we investigated the effect of Bifidobacterium longum BB536 on pellagra-related nausea caused by pirfenidone in our mouse model. Our pharmacological data indicated that pirfenidone (PFD) causes modulation of the gut microbiota profile, which appeared to play an important role in the development of pellagra-related nausea. A gut microbiota-mediated protective effect of B. longum BB536 against nausea caused by PFD was also identified. Finally, the urinary ratio of nicotinamide/N-methylnicotinamide was shown to be a biomarker of pellagra-like adverse effects induced by PFD, and it may contribute to the prevention of these effects in patients with idiopathic pulmonary fibrosis.

HIV Infection, Chromosome Instability, and Micronucleus Formation

Genome integrity is critical for proper cell functioning, and chromosome instability can lead to age-related diseases, including cancer and neurodegenerative disorders. Chromosome instability is caused by multiple factors, including replication stress, chromosome missegregation, exposure to pollutants, and viral infections. Although many studies have investigated the effects of environmental or lifestyle genotoxins on chromosomal integrity, information on the effects of viral infections on micronucleus formation and other chromosomal aberrations is still limited. Currently, HIV infection is considered a chronic disease treatable by antiretroviral therapy (ART). However, HIV-infected individuals still face important health problems, such as chronic inflammation and age-related diseases. In this context, this article reviews studies that have evaluated genomic instability using micronucleus assays in the context of HIV infection. In brief, HIV can induce chromosome instability directly through the interaction of HIV proteins with host DNA and indirectly through chronic inflammation or as a result of ART use. Connections between HIV infection, immunosenescence and age-related disease are discussed in this article. The monitoring of HIV-infected individuals should consider the increased risk of chromosome instability, and lifestyle interventions, such as reduced exposure to genotoxins and an antioxidant-rich diet, should be considered. Therapies to reduce chronic inflammation in HIV infection are needed.

Interactions among the mycobiome, bacteriome, inflammation, and diet in people living with HIV

While the intestinal microbiome seems a major driver of persistent immune defects in people with HIV (PWH), little is known about its fungal component, the mycobiome. We assessed the inter-kingdom mycobiome-bacteriome interactions, the impact of diet, and the association with the innate and adaptive immunity in PWH on antiretroviral therapy. We included 24 PWH individuals and 12 healthy controls. We sequenced the Internal Transcribed Spacer 2 amplicons, determined amplicon sequence variants, measured biomarkers of the innate and adaptive immunity in blood and relations with diet. Compared to healthy controls, PWH subjects exhibited a distinct and richer mycobiome and an enrichment for Debaryomyces hansenii, Candida albicans, and Candida parapsilosis. In PWH, Candida and Pichia species were strongly correlated with several bacterial genera, including Faecalibacterium genus. Regarding the links between the mycobiome and systemic immunology, we found a positive correlation between Candida species and the levels of proinflammatory cytokines (sTNF-R2 and IL-17), interleukin 22 (a cytokine implicated in the regulation of mucosal immunity), and CD8+ T cell counts. This suggests an important role of the yeasts in systemic innate and adaptive immune responses. Finally, we identified inter-kingdom interactions implicated in fiber degradation, short-chain fatty acid production, and lipid metabolism, and an effect of vegetable and fiber intake on the mycobiome. Therefore, despite the great differences in abundance and diversity between the bacterial and fungal communities of the gut, we defined the changes associated with HIV, determined several different inter-kingdom associations, and found links between the mycobiome, nutrient metabolism, and systemic immunity.