SIRT1/3/6 Landscape of Human Longevity: A Sex- and Health-Stratified Pilot Study.

Sirtuins (SIRT1-SIRT7) are NAD⁺-dependent deacetylases that link cellular energy status to chromatin maintenance, mitochondrial function and inflammatory signaling. While modulation of SIRT1, SIRT3 and SIRT6 extends lifespan in model organisms, evidence in extreme-age humans is scarce. We quantified protein and mRNA levels, and protein-to-mRNA ratios for SIRT1, SIRT3 and SIRT6 in buccal epithelial cells obtained from healthy young adults, middle/late-aged individuals and nonagenarians/centenarians residing in a longevity-enriched region of south-eastern Azerbaijan. The cohort comprised 23 participants, stratified by sex and cardiovascular disease (CVD) status (5 per sex/CVD subgroup). This design allows us to: (1) define a baseline "sirtuin profile" of healthy longevity, (2) evaluate the impact of CVD as a prevalent age-related pathology, and (3) explore potential sex-specific modulation. These findings establish an initial human framework linking sirtuin translational control to healthy ageing and cardiovascular health.