Posted on: March 14, 2005
Hair graying is the most obvious sign of aging in humans, yet its mechanism is largely unknown. New research data suggest that hair graying is caused by defective self-maintenance of melanocyte (pigment) stem cells.
Loss of pigment cells (arrowheads) from the hair follicles with the age
Transgenic mice with selective loss of Bcl2 gene (Bcl2 protein normally protects cells from death) undergo premature graying. This graying in mice is associated with death of pigment stem cells in hair follicles.
Premature hair graying in transgenic mouse
Furthermore, physiologic aging of melanocyte stem cells in human hairs is associated with ectopic pigmentation or differentiation of these stem cells. This data suggest that administration of anti-cell death drugs can prevent or delay age-dependent hair graying.
Based on: Nishimura EK et. al.,
Mechanisms of hair graying: incomplete melanocyte stem cell maintenance in the niche. Science. Feb, 2005 |
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