Therapeutic Modulation of Nitric Oxide Pathways to Address Insulin Resistance in Cardiovascular-Kidney-Metabolic Syndrome.

Cardiovascular-kidney-metabolic (CKM) syndrome encompasses the convergent pathophysiology of obesity, insulin resistance, type 2 diabetes, chronic kidney disease, and cardiovascular disease, conditions whose interactions account for a substantial proportion of cardiovascular morbidity and mortality despite contemporary guideline-directed therapy. Nitric oxide (NO) pathway dysfunction constitutes a unifying mechanism across this continuum, linking endothelial dysfunction, impaired insulin signaling, and multiorgan injury through endothelial NO synthase (eNOS) uncoupling, increased arginase activity, asymmetric dimethylarginine (ADMA) accumulation, and paradoxical inducible NO synthase (iNOS)-driven nitrosative stress. Established cardiometabolic therapies-sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1 RAs), renin-angiotensin-aldosterone system (RAAS) inhibitors, statins, and metformin-improve NO signaling indirectly through reductions in oxidative stress and inflammation yet fail to fully restore NO bioavailability and leave substantial residual cardiovascular and renal risk unaddressed. Direct NO-restoring strategies, including soluble guanylate cyclase (sGC) modulators, arginase inhibition, ADMA-lowering approaches, and microbiome-targeted interventions, demonstrate mechanistic promise in preclinical and early translational studies but currently lack outcome-level evidence. Biomarkers of NO pathway dysfunction-ADMA, flow-mediated dilation (FMD), the tetrahydrobiopterin-dihydrobiopterin (BH4/BH2) ratio, cyclic guanosine monophosphate (cGMP), and endothelial microparticles (EMPs)-offer a foundation for patient phenotyping but remain insufficiently standardized for clinical use. A NO-centered framework provides a biologically coherent model for understanding residual cardiometabolic risk; its translation into personalized therapy will require validated biomarker panels and biomarker-guided outcome trials.