Targeting the NO-cGMP axis in age-related vascular dysfunction: a systematic review and meta-analysis of preclinical...

Vascular dysfunction in aging is driven by multiple interconnected hallmarks of aging, including DNA damage, oxidative stress, chronic inflammation, mitochondrial dysfunction, and cellular senescence and features by endothelial impairment, inflammation, and reduced nitric oxide-cyclic guanosine monophosphate (NO-cGMP) signaling. Targeting this pathway may offer therapeutic benefit beyond traditional atherosclerosis-focused treatments. A systematic review and meta-analysis were conducted following PRISMA 2020 guidelines and registered in PROSPERO (CRD42025597982, CRD42025597983, CRD42025598016). PubMed and Embase were systematically searched (August 2024, updated September 2025) for preclinical studies investigating the effect of anti-inflammatory agents (DMARDs), phosphodiesterase (PDE) inhibitors, and soluble guanylate cyclase (sGC) modulators targeting the NO-cGMP pathway in aged animal models of vascular dysfunction. Studies were screened in duplicate using predefined criteria, and data extraction was performed using standardized forms. Risk of bias was assessed using the SYRCLE tool with additional reporting quality items. Meta analyses was conducted using multi-level models accounted for data clustering, and heterogeneity was assessed using I² statistics. Thirteen studies in total were included. DMARDs (n = 6 studies) significantly improved ACh-induced vasorelaxation (2.55 [1.68; 3.42]). PDE inhibitors enhanced SNP-induced vasorelaxation (0.5 [0.04; 0.96], n = 5) and microvascular perfusion (0.76 [0.28; 1.25], n = 4) but showed no significant effect on ACh-induced vasorelaxation. Similarly, sGC modulators improved microvascular perfusion (1.12 [0.46; 1.78], n = 2) without significantly affecting ACh-induced vasorelaxation (0.45 [-0.23; 1.13], n = 3). Pooled analysis (of DMARDS, PDE, and sGC) demonstrated overall improvement in both ACh-induced vasorelaxation (1.73 [0.63; 2.82], n = 13) and microvascular function via any modulation within the NO-cGMP pathway (0.89 [0.49; 1.28], n = 6). The risk of bias assessment showed mixed quality across studies, with generally low risk in randomization (except PDE inhibitors), but high risk in power reporting and some concerns in baseline comparability, allocation, and incomplete outcome data. Modulation of the NO-cGMP pathway improves vascular function through complementary mechanisms. While PDE inhibitors and sGC modulators primarily act on downstream smooth muscle signaling, anti-inflammatory strategies may target upstream endothelial dysfunction. These findings support multi-level therapeutic targeting of vascular aging, although they should be interpreted cautiously given potential bias, heterogeneity, and reliance on the quality of included studies.