Regulation of Human Dermal Papilla Cell Production of Insulin-Like Growth Factor Binding Protein-3 by Retinoic Acid, Glucocorticoids, and Insulin-Like Growth Factor-1

The study investigated the effects of insulin-like growth factor-1 (IGF1), glucocorticoids, and retinoids on the production of insulin-like growth factor binding proteins (IGFBPs) by human dermal papilla (DP) cells. It identified IGFBP-3 as being produced and released by these cells, with its levels increasing fivefold by retinoic acid, eightfold by dexamethasone, and tenfold by IGF1. The findings suggested that DP cells, which produce IGF1, are autoregulated by IGFs through the IGF transmembrane receptor kinase. The study proposed a model where retinoids and glucocorticoids inhibit IGF action on DP cells by stimulating IGFBP-3 production, which then binds to free IGF1, reducing its availability to promote hair elongation and maintenance of the anagen phase.