Cognitive and Inflammation Targeted Gut-Brain Interventions in People Living with HIV who are High-Risk Alcohol Users

RC2 Summary The overarching goal of Research Component 2 (RC2) is to determine whether two non-invasive biological interventions, transcutaneous vagal nerve stimulation (tVNS) and a probiotic supplementation intervention (PBI), will improve cognitive and brain functioning, systemic and neuroinflammation, and gut microbiome health in people living

with HIV (PWLH) who are high risk users of alcohol. The study will also delineate mechanisms of the gut-brain axis, which

is particularly relevant, given that the factors underlying adverse cognitive and brain effects of alcohol use among PLWH

remains unresolved. There is also considerable public health significance if beneficial effects of tVNS and/or PBI can be demonstrated, as cognitive disturbances that adversely impact health outcomes, functional abilities and quality of life are common (~ 50% prevalence), despite marked reductions in mortality in the era of antiretroviral therapies (ART).

Among PLWH with reconstituted immune function and undetectable viral loads, comorbid conditions remain common and can have adverse functional consequences. High risk alcohol use, prevalent among PLWH, not only contributes to cognitive and brain dysfunction, but also further exacerbates comorbidities (e.g. liver disease, hepatitis coinfection,

obesity, and cardiovascular and gastrointestinal dysfunction), and reduces treatment adherence while increasing the propensity for high risk sexual behaviors, worse health outcomes, and transmission of the virus. The study’s clinical significance is strong given the need for effective interventions to improve cognition and health outcomes in PLWH.

To test these hypotheses, we will conduct a hybrid randomized clinical trial that will enroll 80 PLWH who are high risk drinkers from our existing research infrastructure supported by the Southern HIV Alcohol Research Consortium (SHARC). In a 2x2 factorial design, participants will be randomly assigned to one of 4 conditions (tVNS+placebo, sham-

stimulaiton+placebo, tVNS+probiotic, sham-stimulation+probiotic). We will obtain data on alcohol consumption, cognitive assessments, blood biomarkers, stool microbiome, and neuroimaging at three timepoints (baseline, 30-days, 90 days).