Hair regeneration from transected follicles in duplicative surgery: rate of success and cell populations involved.

[BACKGROUND] The use of bisected hair follicles in hair transplantation has been previously reported, but the capacity of each half to regenerate the entire hair has not been clarified.

[OBJECTIVE] To evaluate duplicative surgery rate of success and to analyze the cell populations involved in hair regeneration.

[METHODS] We screened 28 patients undergoing duplicative surgery. Approximately 100 hair follicles from each patient were horizontally bisected and implanted. Upper and lower portions were stained for the known epithelial stem cell markers CD200, p63, beta1-integrin, CD34, and K19.

[RESULTS] Similar percentages of hair regrowth after 12 months were observed when implanting the upper (72.7 +/- 0.4%) and lower (69.2 +/- 1.1%) portions. Expression of CD200, p63, and beta1-integrin was detected in both portions, whereas K19 and CD34 stained different cell populations in the upper and lower fragment, respectively.

[CONCLUSION] Duplicative surgery might represent a successful alternative for hair transplantation, because both portions are capable of regenerating a healthy hair. Moreover, our results suggest the possible presence of stem cells in both halves of the follicle.