Molecular mechanisms of androgenetic alopecia.
Level 5 - mechanism / opinion, no new human data
Narrative review of biological mechanisms with no primary human data or systematic search methodology.
PubMed 12213548 · doi:10.1016/s0531-5565(02)00093-1
What was done
This narrative review synthesized the molecular mechanisms of androgenetic alopecia (AGA), focusing on androgen metabolism, receptor binding, dermal papilla signaling, established pharmacological mechanisms (finasteride and minoxidil), and the role of microscopic follicular inflammation.
What was found
The abstract reports no quantitative experimental data or statistical estimates. It outlines that AGA involves elevated dihydrotestosterone (DHT) levels and increased androgen receptor expression in the predisposed scalp. Testosterone conversion by 5-alpha-reductase within the dermal papilla regulates hair follicle growth factors. Proven treatments include oral finasteride (type 2 5-alpha-reductase inhibitor) and topical minoxidil (an ATP-sensitive potassium channel opener that stimulates VEGF in dermal papilla cells). Because response to these agents is variable, sustained microscopic follicular inflammation and connective tissue remodeling are proposed as cofactors in permanent hair loss.
Why it matters
It outlines the biological rationale for standard anti-androgen and vasodilatory treatments while framing persistent tissue inflammation as a possible explanation for limited treatment efficacy.
Limits
The abstract describes a narrative review with no primary clinical data, systematic search protocol, or meta-analytic pooling. Specific effect sizes, response rates, and demographic details are not provided.
Cited by
- supports The scalp skin has a high density and expression of 5-alpha reductase enzymes that locally convert testosterone to dihydrotestosterone (DHT).