Age-related changes of human serum Sirtuin6 in adults.

BACKGROUND: Aging is a natural life process and with an aging population, age-related diseases (e.g. type 2 diabetes mellitus (T2DM), atherosclerosis-based cardiovascular diseases) are the primary mortality cause in older adults. Telomerase is often used as an aging biomarker. Detection and characterization of novel biomarkers can help in a more specific and sensitive identification of a person's aging status. Also, this could help in age-related diseases early prevent, ultimately prolonging the population's life span. Sirtuin 6 (Sirt6) - a member of the Sirtuins NAD+-dependent histone deacetylases family - is mainly intracellularly expressed, and is reported to be involved in the regulation of aging and aging-related diseases. Whether serum Sirt6 is correlated with aging and could be used as an aging biomarker is unknown. In the present study, we aimed to investigate the age-related Sirt6 changes in the serum of human adults. METHODS: Participants were divided into three groups according to age: 20-30 years (Young); 45-55 years (Middle-aged); and ≥ 70 years (Old). The Sirt6 and telomerase serum concentrations were determined by ELISA. The Sirt6 and human telomerase reverse transcriptase (hTERT) expression in vessels from amputated human lower limbs were analyzed using real-time quantitative PCR (RT-qPCR) and immunohistochemical staining. The relationships between variables were evaluated by Pearson correlation analysis. RESULTS: The Sirt6 and telomerase serum levels reduced with an increase in age. A similar tendency was observed for Sirt6 and hTERT in the vessel. Serum levels of Sirt6 were higher in females compared with males. Pearson's regression analysis revealed that the Sirt6 serum level positively correlated with telomerase (r = 0.5743) and both were significantly negatively correlated with age (r = - 0.5830 and r = - 0.5993, respectively). CONCLUSIONS: We reported a negative correlation between serum Sirt6 concentration and aging in human beings. Therefore, the Sirt6 serum level is a potential sex-specific aging marker.