Perifollicular fibrosis: pathogenetic role in androgenetic alopecia

Biol Pharm Bull. 2006 Jun;29(6):1246-50. doi: 10.1248/bpb.29.1246.

Abstract

Androgenetic alopecia (AGA) is a dihydrotestosterone (DHT)-mediated process, characterized by continuous miniaturization of androgen reactive hair follicles and accompanied by perifollicular fibrosis of follicular units in histological examination. Testosterone (T: 10(-9)-10(-7) M) treatment increased the expression of type I procollagen at mRNA and protein level. Pretreatment of finasteride (10(-8) M) inhibited the T-induced type I procollagen expression at mRNA (40.2%) and protein levels (24.9%). T treatment increased the expression of transforming growth factor-beta 1 (TGF-beta1) at protein levels by 81.9% in the human scalp dermal fibroblasts (DFs). Pretreatment of finasteride decreased the expression of TGF-beta1 protein induced by an average of T (30.4%). The type I procollagen expression after pretreatment of neutralizing TGF-beta1 antibody (10 microg/ml) was inhibited by an average of 54.3%. Our findings suggest that T-induced TGF-beta1 and type I procollagen expression may contribute to the development of perifollicular fibrosis in the AGA, and the inhibitory effects on T-induced procollagen and TGF-beta1 expression may explain another possible mechanism how finasteride works in AGA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alopecia / etiology*
  • Alopecia / metabolism
  • Alopecia / pathology*
  • Antibodies, Monoclonal / pharmacology
  • Blotting, Western
  • Cell Culture Techniques
  • Cells, Cultured
  • Collagen Type I / antagonists & inhibitors
  • Collagen Type I / biosynthesis
  • Enzyme-Linked Immunosorbent Assay
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Fibroblasts / pathology
  • Fibrosis
  • Finasteride / pharmacology
  • Hair Follicle / metabolism
  • Hair Follicle / pathology*
  • Humans
  • RNA, Messenger / antagonists & inhibitors
  • RNA, Messenger / biosynthesis
  • Reverse Transcriptase Polymerase Chain Reaction
  • Testosterone / pharmacology
  • Transforming Growth Factor beta1 / antagonists & inhibitors
  • Transforming Growth Factor beta1 / biosynthesis

Substances

  • Antibodies, Monoclonal
  • Collagen Type I
  • RNA, Messenger
  • Transforming Growth Factor beta1
  • Testosterone
  • Finasteride