Hair loss is the commonest problem in both males and females. If hair loss is not treated in time then this may lead to baldness called alopecia. The cause of hair loss are many, commonly the causes are androgen, genetic, nutrition, and stress. These causative factors lead to alteration in hair cycle and decrease in stem cell activity and hair regeneration capability of the hair follicle.
The stem cells present in the hair follicle play a key role in the hair cycling process and regeneration of hair follicles. the existing pharmacological measures are not capable to target all the causes of hair loss. The stem cells from different sources can be used to reverse the pathological mechanism causing hair loss, regeneration of complete hair follicles from their parts, and neogenesis of the complete hair follicles from stem cell culture with isolated cells or tissue engineering.
Stem Cells in Hair Follicle
The hair follicles have a niche for matured stem cells called hair follicles stem cells (HFSC) sitting in bulge region which is near the attachment of arrector pilli muscles. this bulge has epithelial and melanocytes stem cells. the HFSC are also situated in outer root sheath within the region of the proximal end of isthmus. The HFSCs takes part in regeneration of epidermal cells , structures of hair follicles and sebaceous glands. the another type of stem cells in hair follicles are dermal papilla cells (DPCs) lie in the bulb of hair follicles. The DPC plays important role in induction and regulation of hair growth and the formation of new hair follicle.
Use of Stem Cells
In the current state of knowledge, the stem cells can be used to regenerate hair in the following therapeutic strategies-
Reversing the pathological mechanism which contributes to hair loss especially in androgenetic alopecia.
Regeneration of complete hair follicles from their parts like cells in bulge can regenerate a whole hair. (still, this is under progress)
Neogenesis of hair follicles from a stem cell culture with isolated cells or tissue engineering. ( still, this is under progress)
Sources of Stem Cells
Autologous hair follicles –
a) HFSCs-from bulge of hair follicle
b) DSCs-hair bulb
Extra hair follicle source like-adipose derived stem cells, Bone marrow pluripotent stem cells.
Stem Cells From Autologous Hair Follicles
Separation of stem cells from hair follicles can be done by two methods.
One is the enzymatic disaggregation process in which the stem cells are separated using trypsin enzyme. These are further centrifuged and these are mix with PRP solution and injected in the scalp. At Rejuvenate Hair Transplant Centre this method is used during a hair transplant.
Mechanical separation- Gentle et al demonstrated the application of an innovative regeneracons bioreactor (Certificate CE class-I) to provide autologous hair follicle stem cells and their immediate use in clinical practice. This is a medical device for automated mechanical disaggregation.