Aging of diabetic and nondiabetic skin fibroblasts in vitro: life span and sequential growth curves

Skin fibroblasts from age-matched normal and juvenile diabetic (IDDM) subjects were studied throughout their life span in vitro. The number of mean population doublings (MPD) attained at senescence was determined. Sequential 5-day growth curves were constructed. Normal cells were compared to cells from diabetics with recent onset of disease, 1-5 years, 6-10 years, and greater than 10 years of insulin therapy. A trend of decreasing MPD in vitro with increasing duration of diabetes in vivo was found. The growth potential of all cells (sequential growth curves) decreased with increasing time in vitro. The confluent density (Day 5) of diabetic (10 years' duration) cells was significantly lower than that for normal cells at Stage 2 of growth (passage 6-10). The in vitro aging of cells from diabetics (recent onset) was essentially the same as that of normal cells.