Supplementing HIV-ART with cannabinoids increases serotonin, BHB, and Ahr signaling while reducing secondary bile acids and acylcholines.

Despite effective antiretroviral therapy (ART), people with HIV (PWH) experience persistent inflammation and metabolic dysfunction, increasing their risk for non-AIDS comorbidities. Accordingly, we evaluated the effects of long-term/low-dose Δ9-tetrahydrocannabinol (THC) supplementation in simian immunodeficiency virus (SIV)-infected, ART-treated rhesus macaques (RMs). THC significantly increased plasma/jejunum serotonin and indole-3-propionate, enhancing gut-brain communication through up-regulation of serotonin receptors (HTR4/HTR7) and aryl hydrocarbon receptor (Ahr) signaling via a cannabinoid receptor (CBR)-2-mediated mechanism. Furthermore, THC enriched cholesterol-metabolizing Oscillibacter and reduced plasma cholesterol and toxic secondary bile acids (SBAs), thus improving cholesterol and SBA homeostasis. Furthermore, THC increased β-hydroxybutyrate (BHB) levels via a CBR1-mediated mechanism, suggesting enhanced hepatic fatty acid oxidation for metabolic and cardiovascular health. THC restored ART/SIV-induced elevation of pro-inflammatory and cardiotoxic long-chain acylcholines to preinfection levels. THC-treated RMs maintained viral suppression despite reduced plasma ART levels, suggesting diminished ART-related toxicity. Our findings demonstrate phytocannabinoids to be a safe adjunct therapy alongside ART to mitigate chronic inflammation and metabolic dysfunction in PWH.