Nifedipine-modulated gut microbiota attenuates hypertensive vascular injury through Bifidobacterium-associated inosine-Adora2b signaling

Although antihypertensive drugs mitigate hypertensive vascular injury, their vascular benefits are not fully explained by blood pressure reduction alone. Many cardiovascular drugs reshape the gut microbiota, which in turn influences their vascular pharmacology. We therefore investigated whether gut microbiota remodeling contributes to nifedipine-mediated vascular protection in high-salt hypertensive rats and a pilot patient cohort. Combining 16S rRNA sequencing, untargeted metabolomics, fecal microbiota transplantation, microbiota depletion, supplementation, and selective receptor antagonism, we found that nifedipine ameliorated gut dysbiosis. Transplantation of nifedipine-modulated microbiota improved intestinal barrier integrity and reduced vascular inflammation, oxidative stress, collagen deposition, and vascular smooth muscle cell (VSMC) phenotypic switching, while only marginally lowering blood pressure. Conversely, microbiota depletion markedly attenuated these vascular benefits despite preserving nifedipine-induced blood pressure lowering. These vascular benefits were associated with nifedipine-restored Bifidobacterium animalis subsp. lactis 420 (B420) and increased inosine availability. Supplementation with either recapitulated major vascular protective effects of nifedipine without statistically significant changes in blood pressure. In hypertensive patients, nifedipine treatment was associated with higher intestinal B420 abundance and inosine levels. In vitro, inosine modulated macrophages in an Adora2b- and Rap1-dependent manner, with accompanying changes in cAMP and KLF4, ameliorating VSMC dysfunction via paracrine signaling. In vivo, systemic Adora2b antagonism attenuated the vascular protective effects of both inosine and B420. Together, our findings support a gut microbiota-dependent component of nifedipine-mediated vascular protection that extends beyond blood pressure lowering, involving B420, increased inosine availability, and Adora2b signaling. We also nominate B420 and inosine as candidate adjuncts to calcium channel blocker therapy.