http://www.ncbi.nlm.nih.gov/pubmed/19416266
l-Ascorbic acid 2-phosphate promotes elongation of hair shafts via the
secretion of insulin-like growth factor-1 from dermal papilla cells
through phosphatidylinositol 3-kinase.
Kwack MH, Shin SH, Kim SR, Im SU, Han IS, Kim MK, Kim JC, Sung YK.
Department of Immunology, School of Medicine, Kyungpook National
University, 101 Dong-In-Dong, Chung-Gu, Daegu 700-422, Korea.
Summary Background l-Ascorbic acid 2-phosphate (Asc 2-P), a derivative
of l-ascorbic acid, promotes elongation of hair shafts in cultured human
hair follicles and induces hair growth in mice. Objectives To
investigate whether the promotion of hair growth by Asc 2-P is mediated
by insulin-like growth factor-1 (IGF-1) and, if so, to investigate the
mechanism of the Asc 2-P-induced IGF-1 expression. Methods Dermal
papilla (DP) cells were cultured and IGF-1 level was measured by reverse
transcription-polymerase chain reaction and enzyme-linked immunosorbent
assay after Asc 2-P treatment in the absence or presence of LY294002, a
phosphatidylinositol 3-kinase (PI3K) inhibitor. Also, hair shaft
elongation in cultured human scalp hair follicles and proliferation of
cocultured keratinocytes were examined after Asc 2-P treatment in the
absence or presence of neutralizing antibody against IGF-1. In addition,
keratinocyte proliferation in cultured hair follicles after Asc 2-P
treatment in the absence or presence of LY294002 was examined by Ki-67
immunostaining. Results IGF-1 mRNA in DP cells was upregulated and IGF-1
protein in the conditioned medium of DP cells was significantly
increased after treatment with Asc 2-P. Immunohistochemical staining
showed that IGF-1 staining is increased in the DP of cultured human hair
follicles by Asc 2-P. The neutralizing antibody against IGF-1
significantly suppressed the Asc 2-P-mediated elongation of hair shafts
in hair follicle organ culture and significantly attenuated Asc
2-P-induced growth of cocultured keratinocytes. LY294002 significantly
attenuated Asc 2-P-inducible IGF-1 expression and proliferation of
follicular keratinocytes in cultured hair follicles. Conclusions These
data show that Asc 2-P-inducible IGF-1 from DP cells promotes
proliferation of follicular keratinocytes and stimulates hair follicle
growth in vitro via PI3K.
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