title: Role of Arachidonic Acid in Promoting Hair Growth.
abstract: BACKGROUND
  Arachidonic acid (AA) is an omega-6 polyunsaturated fatty acid present in all mammalian cell membranes, and involved in the regulation of many cellular processes, including cell survival, angiogenesis, and mitogenesis. The dermal papilla, composed of specialized fibroblasts located in the bulb of the hair follicle, contributes to the control of hair growth and the hair cycle.
  
  
  OBJECTIVE
  This study investigated the effect of AA on hair growth by using in vivo and in vitro models.
  
  
  METHODS
  The effect of AA on human dermal papilla cells (hDPCs) and hair shaft elongation was evaluated by MTT assay and hair follicle organ culture, respectively. The expression of various growth and survival factors in hDPCs were investigated by western blot or immunohistochemistry. The ability of AA to induce and prolong anagen phase in C57BL/6 mice was analyzed.
  
  
  RESULTS
  AA was found to enhance the viability of hDPCs and promote the expression of several factors responsible for hair growth, including fibroblast growth factor-7 (FGF-7) and FGF-10. Western blotting identified the role of AA in the phosphorylation of various transcription factors (ERK, CREB, and AKT) and increased expression of Bcl-2 in hDPCs. In addition, AA significantly promoted hair shaft elongation, with increased proliferation of matrix keratinocytes, during ex vivo hair follicle culture. It was also found to promote hair growth by induction and prolongation of anagen phase in telogen-stage C57BL/6 mice.
  
  
  CONCLUSIONS
  This study concludes that AA plays a role in promoting hair growth by increasing the expression of growth factors in hDPCs and enhancing follicle proliferation and survival.
authors: Department of Dermatology, Seoul National University College of Medicine, Seoul, Korea.
authors: Semchin
authors: S
authors: Munkhbayar
authors: Institute of Human-Environment Interface Biology, Seoul National University Medical Research Center, Seoul, Korea.; Laboratory of Cutaneous Aging and Hair Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
authors: Sunhyae
authors: S
authors: Jang
authors: Institute of Human-Environment Interface Biology, Seoul National University Medical Research Center, Seoul, Korea.; Laboratory of Cutaneous Aging and Hair Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
authors: A-Ri
authors: AR
authors: Cho
authors: Institute of Human-Environment Interface Biology, Seoul National University Medical Research Center, Seoul, Korea.; Laboratory of Cutaneous Aging and Hair Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
authors: Soon-Jin
authors: SJ
authors: Choi
authors: Institute of Human-Environment Interface Biology, Seoul National University Medical Research Center, Seoul, Korea.; Laboratory of Cutaneous Aging and Hair Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
authors: Chang Yup
authors: CY
authors: Shin
authors: Department of Dermatology, Seoul National University College of Medicine, Seoul, Korea.
authors: Hee Chul
authors: HC
authors: Eun
authors: Department of Dermatology, Seoul National University College of Medicine, Seoul, Korea.; Institute of Human-Environment Interface Biology, Seoul National University Medical Research Center, Seoul, Korea.; Laboratory of Cutaneous Aging and Hair Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
authors: Kyu Han
authors: KH
authors: Kim
authors: Department of Dermatology, Seoul National University College of Medicine, Seoul, Korea.; Institute of Human-Environment Interface Biology, Seoul National University Medical Research Center, Seoul, Korea.; Laboratory of Cutaneous Aging and Hair Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
authors: Ohsang
authors: O
authors: Kwon
keywords: Arachidonic acid; Hair; Hair follicle