Methods/Technique: Subcutaneous adipose tissue samples are collected from male and female patients (ages 18-85), who are undergoing aesthetic surgery by plastic surgeons at the University of Pennsylvania. Adipocytes, stromal vascular fraction (SVF) and adipose-derived stem cells (ADSC) are isolated from each specimen and examined in parallel. RNA and protein expression is examined in a multi-tiered approach that establishes molecular changes associated with aging in a genome-wise and pathway-specific manner.
Results/Complications: We present genome-wide RNA expression differences acquired during the aging process discovered using microarray chip technology in our model of adipose tissue aging of purified populations of adipocytes, SVFs, and ADSCs from human subcutaneous adipose tissues of different ages, clinical aging phenotypes, and anatomical locations. Secondly, we demonstrate that the human Sirtuin histone deacetylation genes (SIRT1-7), which are known to be involved in longevity and adipose metabolism, regulate adipose tissue aging in a differential manner via specific effects on cell type, anatomical region and aging phenotype. Finally, we demonstrate that features originally thought to be specific to brown adipose tissue (BAT) may in fact be responsible for the variance in subcutaneous adipose tissue aging phenotypes.
Conclusion: We have established that subcutaneous adipose tissue is an excellent model for the investigation of human aging. By examining molecular changes associated with aging in a genome-wise and pathway-specific manner, we are advancing the understanding of how human tissues age.