Scarring alopecia and the PPAR-gamma connection

J Invest Dermatol. 2009 May;129(5):1066-70. doi: 10.1038/jid.2008.425.


The pathobiology of primary cicatricial ("scarring") alopecia (PCA) remains poorly understood and underinvestigated. In this issue, Karnik et al. identify a previously unsuspected player, peroxisome proliferator-activated receptor-gamma (PPARgamma), in the pathogenesis of the most frequent form of PCA, lichen planopilaris (LPP). The authors show that PPARgamma is required for maintenance of a functional epithelial stem cell compartment in murine hair follicles, that the targeted deletion of PPARgamma in the bulge/isthmus area of the hair follicle epithelium generates a skin pathology that resembles LPP, and that LPP patients show gene expression changes that indicate a defect in lipid metabolism and peroxisome biogenesis. This study invites the revisitation of many open questions in PCA pathobiology and the exploration of new avenues for future PCA management.

Publication types

  • Comment
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alopecia / etiology*
  • Alopecia / metabolism*
  • Animals
  • Cicatrix / etiology*
  • Cicatrix / metabolism*
  • Disease Models, Animal
  • Hair Follicle / metabolism
  • Humans
  • Lichen Planus / metabolism
  • Lipid Metabolism / physiology
  • Mice
  • PPAR gamma / metabolism*
  • Peroxisomes / metabolism


  • PPAR gamma