Growth Kinetics of Cultured Dermal Papilla and Dermal Sheath Cells from Human Hair Follicles

The study observed the growth kinetics of dermal papilla cells and dermal sheath cells from human hair follicles in vitro. It found that these cells, along with fibroblasts, exhibited three growth phases: a stagnant phase (days 1-4), an exponential growth phase (days 5-11), and a slow growth phase. Epidermal growth factor (EGF) significantly enhanced the growth of all three cell types, particularly dermal sheath cells, while hydrocortisone+insulin and granulocyte macrophage colony-stimulating factor had no significant effect. During the exponential phase, the mean population doubling times were 60 hours for dermal papilla cells, 59.2 hours for dermal sheath cells, and 76.8 hours for fibroblasts. The study concluded that the effects of EGF on cell growth might be related to the presence of receptors in these cells.