- Reaction score
- 95
'Abstract
In mammals, most wounds heal by repair, not regeneration. It now seems that, as they heal, open skin wounds in adult mice form new hair follicles that follow similar developmental paths to those of embryos.
A person whose leg is amputated is left with a stump, whereas some amphibians have the awe-inspiring ability to regenerate new limbs after amputation. Overall, adult mammals have very limited regenerative ability; this could be due to a lack of stem cells or the absence of proper environmental signals. On page 316 of this issue, Ito et al. 1 report an unexpected finding that could change our current understanding of repair and regeneration in adult mammals. They show that the outermost skin layer — the epidermis — of wounded adult mice can regenerate new hair follicles during healing, and that this ability depends on the characteristics of the wound.
Observations some 50 years ago had indicated that, in mice, rabbits and humans2–5, some hair follicles develop anew after wounding. But because of a lack of definitive evidence, these findings had generally been discounted. Now, using advanced cellular and molecular techniques to study normal adult mice, Ito et al. have rediscovered these forgotten phenomena. The authors made large wounds (1–2.25 cm2) on the animals’ backs, to the full depth of the skin. They found that if, following wound closure, the healed wound was larger than around 0.5 cm in diameter, new hairs formed at the centre of the wound. An examination of the sections of the healed skin revealed changes that resembled various stages of embryonic hair-follicle development. The new hair follicles grew, passed through the hair cycle, and eventually became indistinguishable from neighbouring hair (Fig. 1).
[...]
As human and mouse skin heals differently, the results of Ito et al. 1 are yet to be verified in humans. However, these findings will undoubtedly inspire new thinking in the management of alopecia, in tissue engineering and in the regeneration of other organs.'
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4377231/
In mammals, most wounds heal by repair, not regeneration. It now seems that, as they heal, open skin wounds in adult mice form new hair follicles that follow similar developmental paths to those of embryos.
A person whose leg is amputated is left with a stump, whereas some amphibians have the awe-inspiring ability to regenerate new limbs after amputation. Overall, adult mammals have very limited regenerative ability; this could be due to a lack of stem cells or the absence of proper environmental signals. On page 316 of this issue, Ito et al. 1 report an unexpected finding that could change our current understanding of repair and regeneration in adult mammals. They show that the outermost skin layer — the epidermis — of wounded adult mice can regenerate new hair follicles during healing, and that this ability depends on the characteristics of the wound.
Observations some 50 years ago had indicated that, in mice, rabbits and humans2–5, some hair follicles develop anew after wounding. But because of a lack of definitive evidence, these findings had generally been discounted. Now, using advanced cellular and molecular techniques to study normal adult mice, Ito et al. have rediscovered these forgotten phenomena. The authors made large wounds (1–2.25 cm2) on the animals’ backs, to the full depth of the skin. They found that if, following wound closure, the healed wound was larger than around 0.5 cm in diameter, new hairs formed at the centre of the wound. An examination of the sections of the healed skin revealed changes that resembled various stages of embryonic hair-follicle development. The new hair follicles grew, passed through the hair cycle, and eventually became indistinguishable from neighbouring hair (Fig. 1).
[...]
As human and mouse skin heals differently, the results of Ito et al. 1 are yet to be verified in humans. However, these findings will undoubtedly inspire new thinking in the management of alopecia, in tissue engineering and in the regeneration of other organs.'
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4377231/
