Recognizing senescent vascular smooth muscle cells in diabetic atherosclerosis: biomarkers, transcriptomic signatures, and methodological validity

Diabetic atherosclerosis represents the most severe macrovascular complication of diabetes mellitus and a major contributor to global morbidity and mortality. Senescence of vascular smooth muscle cells (VSMCs) has been increasingly recognized as a central mechanism driving plaque formation, progression, and instability under diabetic conditions. Yet identifying senescent VSMCs reliably remains difficult: available biomarkers lack specificity, transcriptomic signatures vary considerably across studies, and no consensus has emerged on how senescence should be verified methodologically. This review consolidates current knowledge on senescent VSMC identification in diabetic atherosclerosis. We begin with the pathobiological routes through which hyperglycemia drives VSMC senescence, including oxidative stress, DNA damage, mitochondrial dysfunction, and metabolic reprogramming. We then present a multidimensional classification of senescence-associated biomarkers, spanning cell cycle regulators, senescence-associated β-galactosidase (SA-β-gal), telomere-related markers, the senescence-associated secretory phenotype (SASP), calcification markers, and emerging non-coding RNA signatures, and assess the applicability and shortcomings of each. Transcriptomic signatures derived from single-cell RNA sequencing, spatial transcriptomics, and flow cytometry are then integrated to map the heterogeneity of senescent VSMC subpopulations and their functional roles within atherosclerotic plaques. We next appraise the methodological validity of existing detection strategies, comparing in vitro high-glucose models, in vivo diabetic animal models, and clinical specimens, and trace the sources of inter-study inconsistency, including spatial heterogeneity, cross-sectional designs, and the absence of standardized protocols. Finally, we outline a stepwise identification pipeline extending from molecular markers to functional validation and multi-omics integration, and consider future prospects such as senolytic therapies and targeted delivery systems. By providing this methodological reference, we hope to support both basic research and clinical translation and to push the field toward more precise, standardized identification of senescent VSMCs.