Background: Androgenic alopecia (AGA) is the most common type of baldness in men. Although etiological studies have proved that androgen is one of the causes of this symptom, the defined molecular mechanism underlying androgen-related actions remains largely unknown.
Objectives: To clarify the difference in the gene expression profile of dermal papilla cells (DPCs) in skin affected by baldness.
Methods: DNA macroarray study was carried out on cultured DPCs from AGA skin comparing with DPCs from skin that is not affected by baldness.
Results: From DNA macroarray analysis, we observed that 107 of the 1185 analyzed genes had differing expression levels. A marked difference was observed in the decreased gene expression of BMP2 and ephrin A3 and up-regulated in NT-4 gene. In order to clarify the roles of BMP2 and ephrin A3 in the hair follicles, we examined the proliferation of hair follicle keratinocyte and expression of a hair acidic keratin gene. Both BMP2 and ephrin A3 raised the proliferation rate of the outer root sheath cells (ORSCs) and induced gene expression in acidic hair keratin 3-II.
Conclusion: These results lead us to the hypothesis that both BMP2 and ephrin A3 function as hair growth promoting factors in the hair cycle.
Very important research here:
Pathogenetic mechanisms in androgenetic alopecia are not yet fully understood; however, it is commonly accepted that androgens like testosterone (T) and 5-dihydrotestosterone (5-DHT) inhibit hair follicle activity with early induction of the catagen. Thus, we investigated the influence of T and 5-DHT on proliferation, cell death and bcl-2/bax expression in cultured dermal papilla cells (DPC) from nonbalding scalp regions of healthy volunteers. T and 5-DHT induced apoptosis in DPC in a dose-dependent and time-related manner; in addition a necrotic effect due to T at 10-5M was found. Interestingly, bcl-2 protein expression was decreased in T- and 5-DHT-treated cells, leading to an increase in the bax/bcl-2 ratio. In addition, T and 5-DHT induced proteolytic cleavage of caspase 8 and inhibited proliferation of DPC at 10-5M. High concentrations of T and 5-DHT were needed to induce apoptotic effects in DPC. These data suggest that DPC from nonbalding scalp regions do have the capacity to undergo apoptosis, but need a high androgen stimulus. The present study provides an interesting new pathogenetic approach in androgenetic alopecia.
Copyright © 2006 S. Karger AG, Basel
In other words, the “donor hair” you have could go bald if you have baldness, but just doesn’t have high enough androgen stimulis to do so, because they have less androgen receptors on them as researchers have noted. If you could up DHT high enough, you’d lose much of your donor hair.
Green tea and dermal papillas and bax/bcl info:
Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG).Kwon OS, Han JH, Yoo HG, Chung JH, Cho KH, Eun HC, Kim KH.
Department of Dermatology, Seoul National University College of Medicine, Laboratory of Cutaneous Aging and Hair Research, Seoul National University Hospital, Institute of Dermatological Science, Seoul National University, 110-744 Seoul, Republic of Korea.
Green tea is a popular worldwide beverage, and its potential beneficial effects such as anti-cancer and anti-oxidant properties are believed to be mediated by epigallocatechin-3-gallate (EGCG), a major constituent of polyphenols. Recently, it was reported that EGCG might be useful in the prevention or treatment of androgenetic alopecia by selectively inhibiting 5alpha-reductase activity. However, no report has been issued to date on the effect of EGCG on human hair growth. This study was undertaken to measure the effect of EGCG on hair growth in vitro and to investigate its effect on human dermal papilla cells (DPCs) in vivo and in vitro. EGCG promoted hair growth in hair follicles ex vivo culture and the proliferation of cultured DPCs. The growth stimulation of DPCs by EGCG in vitro may be mediated through the upregulations of phosphorylated Erk and Akt and by an increase in the ratio of Bcl-2/Bax ratio. Similar results were also obtained in in vivo dermal papillae of human scalps. Thus, we suggest that EGCG stimulates human hair growth through these dual proliferative and anti-apoptotic effects on DPCs.
PMID: 17092697 [PubMed - indexed for MEDLINE]
You might want to drink or topically apply some green tea along with your finasteride in other words.
If there are any particular genes that could be inhibited “downstream” that are the cause of Androgenic Alopecia, identifying them may lead to a way to treat common baldness WITHOUT FOOLING WITH YOUR HORMONES. TGF-beta, DKK-1, Bcl/Bax, ephrin A-3 would seem to be high on the list of things “to be blocked” anyway.