M2 Macrophages Promote Wound-Induced Hair Neogenesis

The study from August 31, 2018, established a mouse model of wound-induced hair neogenesis (WIHN), a phenomenon where new hair regeneration occurs in scars. The researchers hypothesized that M2 macrophages, a type of immune cell, were crucially involved in WIHN. They found that these macrophages infiltrated the tissue 2 weeks after wounding and produced various growth factors. Administration of two of these growth factors, Igf1 or Fgf2, promoted WIHN. When macrophages were removed in genetically engineered mice, WIHN decreased. The study concluded that M2 macrophages could promote WIHN through producing a panel of growth factors.