@Belief.. I really think that all of us on here can grow their hair back.
According to this study.. we still all have our follicles.. but the micro-inflammation going on will bring some side-effects , fibrosis, hardening of the collagen, reduction of endothelial microstructures etc.. which takes a lot of time to reverse. This is where the derma roller comes in the game! This is why the new balders should not wait when they start noticing their hair thinning.
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Garza LA,
Yang CC,
Zhao T,
Blatt HB,
Lee M,
He H,
Stanton DC,
Carrasco L,
Spiegel JH,
Tobias JW,
Cotsarelis G.
Source
Department of Dermatology, Kligman Laboratories, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Abstract
Androgenetic alopecia (Androgenetic Alopecia), also known as common baldness, is characterized by a marked decrease in hair follicle size, which could be related to the loss of hair follicle stem or progenitor cells. To test this hypothesis, we analyzed bald and non-bald scalp from Androgenetic Alopecia individuals for the presence of hair follicle stem and progenitor cells. Cells expressing cytokeratin15 (KRT15), CD200, CD34, and integrin, α6 (ITGA6) were quantitated via flow cytometry. High levels of KRT15 expression correlated with stem cell properties of small cell size and quiescence. These KRT15(hi) stem cells were maintained in bald scalp samples. However, CD200(hi)ITGA6(hi) and CD34(hi) cell populations--which both possessed a progenitor phenotype, in that they localized closely to the stem cell-rich bulge area but were larger and more proliferative than the KRT15(hi) stem cells--were markedly diminished. In functional assays, analogous CD200(hi)Itga6(hi) cells from murine hair follicles were multipotent and generated new hair follicles in skin reconstitution assays. These findings support the notion that a defect in conversion of hair follicle stem cells to progenitor cells plays a role in the pathogenesis of Androgenetic Alopecia.