Evaluation of Gene Expression Patterns in Micrografts Demonstrate Induction of Catagen-Like Processes During Storage.

Abstract

Alterations of gene expression patterns may contribute to the commonly observed transient reduction of hair shaft elongation in hair restoration surgery. To elucidate the molecular causes, we evaluated changes in gene expression patterns in hair follicle micrografts during storage. Micrografts with different amounts of adjacent connective tissue (regular, skinny, and chubby) were stored for different periods, and the expression of key genes was determined: dermal papilla (DP): FGF7, alkaline phosphatase (ALP), versican; outer root sheath: Krt15; inner root sheath: Krt 25; cuticula: Krt85; Henle layer: filaggrin; genes related to apoptosis and growth/differentiation: Caspase 3, Ovol1, and Foxo1. A significant decrease in FGF7 (4 × 10 fold) was observed after 4 hours, with further decrease after 48 hours. A significant decrease of versican (0.35 fold) and ALP (0.004 fold) was observed after 24 hours of storage. No differences relating to adjacent connective tissue were observed. No changes of different keratins genes or genes related to growth/differentiation and apoptosis were observed. These data clearly demonstrate a reduction in the specific function of cells in the DP, which seem to be the causative for the induction of hair follicle cycling during micrograft preparation and storage.