Obesity in HIV infection: host-pathogen interaction

The Potential of Clostridium butyricum to Preserve Gut Health, and to Mitigate Non-AIDS Comorbidities in People Living with HIV

A dramatic reduction in mortality among people living with HIV (PLWH) has been achieved during the modern antiretroviral therapy (ART) era. However, ART does not restore gut barrier function even after long-term viral suppression, allowing microbial products to enter the systemic blood circulation and induce chronic immune activation. In PLWH, a chronic state of systemic inflammation exists and persists, which increases the risk of development of inflammation-associated non-AIDS comorbidities such as metabolic disorders, cardiovascular diseases, and cancer. Clostridium butyricum is a human butyrate-producing symbiont present in the gut microbiome. Convergent evidence has demonstrated favorable effects of C. butyricum for gastrointestinal health, including maintenance of the structural and functional integrity of the gut barrier, inhibition of pathogenic bacteria within the intestine, and reduction of microbial translocation. Moreover, C. butyricum supplementation has been observed to have a positive effect on various inflammation-related diseases such as diabetes, ulcerative colitis, and cancer, which are also recognized as non-AIDS comorbidities associated with epithelial gut damage. There is currently scant published research in the literature, focusing on the influence of C. butyricum in the gut of PLWH. In this hypothesis review, we speculate the use of C. butyricum as a probiotic oral supplementation may well emerge as a potential future synergistic adjunctive strategy in PLWH, in tandem with ART, to restore and consolidate intestinal barrier integrity, repair the leaky gut, prevent microbial translocation from the gut, and reduce both gut and systemic inflammation, with the ultimate objective of decreasing the risk for development of non-AIDS comorbidities in PLWH.

Recent data on the role of antiretroviral therapy in weight gain and obesity in persons living with HIV

PURPOSE OF REVIEW

Antiretroviral therapy (ART) has long been implicated in fat alterations and weight variations leading to cardiometabolic consequences. Recent largely prescribed antiretrovirals (ARVs) from the integrase-strand-transfer-inhibitor (INSTI) class have been associated with excessive weight gain/obesity in a minority of persons with HIV (PWH). As well, in the nucleoside reverse transcriptase inhibitors (NRTI) class, tenofovir-alafenamide (TAF), often replacing tenofovir-disoproxil-fumarate (TDF), has been associated with weight gain, a worrying concern in the present worldwide obesogenic environment. The respective role of the different ARV, the risk factors and the mechanisms remain questionable.

RECENT FINDINGS

The INSTIs dolutegravir (DTG) and bictegravir (BIC) and TAF have a proper effect on weight gain, while efavirenz (EFV) and TDF inhibit it. These effects are reported in ART-naïve PWH, in addition to weight gain resulting from the return to health process, and in ART-controlled PWH. Also, INSTIs induce weight gain in adolescents and excessive weight gain during pregnancy. The effects of INSTIs and TAF are additive. Their trajectory differs. Most of the weight gain is observed during the initial 12-month period.The main risk factors are low CD4+ and high viral load (VL) in ART-naïve PWH, Black race or originating from some African countries and female gender. The role of age and BMI differs between studies. The reversibility of the effect of INSTI and TAF appears limited.Regarding the mechanisms, the INSTIs can directly alter adipose tissue in particular through inhibition of fat beiging, resulting in fat fibrosis and hypertrophy. Macrophage infiltration is decreased. The mechanisms explaining the opposite effects of TDF and TAF remain elusive.

SUMMARY

The specific impact of DTG, BIC and TAF on weight gain/obesity in PWH is confirmed in different populations independently of the weight limiting effect of EFV and TDF. ART-linked excessive weight gain is uncommon. African origin and female sex are risk factors that need to be considered. The mechanisms are better understood for INSTIs but unknown for TDF/TAF. The reversibility of weight gain/obesity when stopping INSTI or TAF remains limited.