Effect of IGF-I on Hair Growth Is Related to the Anti-Apoptotic Effect of IGF-I and Up-Regulation of PDGF-A and PDGF-B

Abstract

BackgroundInsulin-like growth factor-I (IGF-I) shares a high degree of structural and functional homology with insulin and is a potent mitogen supporting cell growth and survival in many kinds of the tissues and cells. It also plays a role in some differentiation and anti-apoptotic functions. In previous reports, it has been shown that IGF-I stimulates hair follicle (HF) growth, maintains the anagen stage, and postpones the catagen stage.ObjectiveThe exact mechanism of the effect of IGF-I on HF growth is not yet established. Therefore, we investigated the relationships between IGF-I and various other factors (i.e. apoptosis related molecules, pro-inflammatory cytokines, other growth factors, etc.) in the control of HF growth.MethodsThe effect of IGF-I on human hair growth was measured using an organ culture model of human HFs and compared with a control group that did not receive IGF-I. We also measured mRNA expression of factors related to hair growth and apoptosis (which was determined by reverse transcription polymerase chain reaction (RT-PCR). RT-PCR was done on days 2, 4, 6, and 8 of organ culture.ResultsIn organ cultured human hair follicles, IGF-I had a positive effect on the rate of linear hair growth. IGF-I maintained the anagen phase. IGF-I increased the expression of platelet-derived growth factor (PDGF)-A, PDGF-B and the expression ratio of Bcl-2/Bax.ConclusionThe effect of IGF-I on hair growth appears to be related to the upregulation of PDGF-A and PDGF-B and to the anti-apoptotic effect of IGF-I.

Highly Upregulated Lhx2 in the Foxn1−/− Nude Mouse Phenotype Reflects a Dysregulated and Expanded Epidermal Stem Cell Niche

“…As evidenced by upstream ‘gateway-keepers’ of differentiation such as Lhx2 it also profoundly affects stem cell niches within the skin. The Nu/Nu phenotype is also likely to offer novel insights in HF morphogenesis and cycling related to interactions between the epithelial and mesenchymal cell lineage with several signaling pathways such as that related to bone morphogenetic proteins (BMP’s) [58], [59], tumor growth factor β (TGF-β) [60] or insulin like growth factor 1 (IGF-1) [61] being worthwhile further investigation.…”

Insulin, Independent of Serum Androgens of Androgen Receptor CAG Repeat Polymorphism, is Associated with Hirsutism in Polycystic Ovary Syndrome

“…According to recent data obtained in cultures of the human hair follicles, IGF-I stimulates the rate of linear hair growth and, on the other hand, reduces apoptosis by increasing expression of platelet-derived growth factor (PDGF)-A, PDGF-B and the ratio of Bcl-2/Bax (23).…”

Phamacopuncture and Dermal Application of Sebalgukhwa-san: Effects on Hair Growth in a Mouse Model of Alopecia

“…It plays a role in cell growth and migration by binding to cell surface receptors. In particular, IGF-1 secreted from the dermal papilla cells of the hair follicle, promotes epithelial cell proliferation, and significantly increases the length of follicular tissue [44,45]. In contrast to VEGF and IGF-1, TGF-β1 reduces hair growth and suppresses proliferation of epithelial cells, resulting in faster regression than normal [46,47].…”