Androgenic Alopecia: Cross-Talk Between Cell Signal Transduction Pathways
May 2017
in “InTech eBooks”
TLDR Hair loss in Androgenetic alopecia (AGA) is due to altered cell sensitivity to hormones, not increased hormone levels. Hair growth periods shorten over time, causing hair to become thinner and shorter. This is linked to miscommunication between cell pathways in hair follicles. There's also a change in gene expression related to blood vessels and cell growth in balding hair follicles. The exact molecular causes of AGA are still unclear.
The 2017 study "Androgenic Alopecia: Cross-Talk Between Cell Signal Transduction Pathways" explored the molecular signaling pathways in dermal papilla cells from balding human scalp. The researchers found that Androgenetic alopecia (AGA) is not caused by increased levels of androgens in the blood, but by altered androgen cell sensitivity. The study also revealed that the duration of fast growth periods (anagen) gradually reduces with each hair cycle, leading to hair follicles becoming narrower and shorter. The basic mechanism of hair growth pathologies consists in discoordination of cross-talk between canonical signaling pathways within hair follicle dermal papilla and hair follicle outer root sheath stem cells. The study concluded that studying AGA mainly focuses on DHT synthesis in the skin and AR signaling affecting cell processes that cause arrest of anagen phase in frontal scalp. The study also found underexpression of vasculature-related genes and overexpression of genes related to cell cycle and mitosis in balding hair follicles. The differential gene expression could be related to cell cycle dysregulation in balding hair follicles. The study concluded that a detailed understanding of the molecular causes of hair loss in AGA had not been reached and that new standardized studies of hair follicle cell cycle in human scalp were required.
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