Signaling Protein Ephrin-A3 Grows New Hair Follicles and Thicker Hair

Could Ephrin-A3 help you grow your very own fur coat? (Photo by Stephen Barnett)

For those interested in the latest studies regarding hair loss, here's an interesting paper by Yamada et al. from this month's issue of the Journal of Dermatological Science:

Ephrin-A3 not only increases the density of hair follicles but also accelerates anagen development in neonatal mice

BACKGROUND: Ephrins are cell-membrane-bound ligands for Eph receptor tyrosine kinases (Eph). Although ephrins are known to regulate a variety of developmental processes, little is known of their role in hair development. Previously, we studied the gene expression of dermal papilla cells from androgenetic alopecia and found that ephrin-A3 was significantly down-regulated.

OBJECTIVE: To characterize the expression of ephrin-A3 in the hair cycle and evaluate the effect of ephrin-A3 on hair growth.

METHODS: We investigated gene expression and protein expression of each ephrin-As and EphAs in the skin of neonatal mice through the first and second hair cycle using quantitative PCR and immunohistochemical analysis, respectively. We also injected ephrin-A3 protein into the skin of neonatal mice and demonstrated the effect of ephrin-A3 on hair follicle development.

RESULTS: Expression of ephrin-A3 revealed a rapid increase at the beginning of the anagen phase, a peak during the mid-anagen, and a rapid fading during the telogen phase. In addition, we found ephrin-A3 protein was expressed in the developing hair follicles with a characteristic spatiotemporal localization. Furthermore, injection of ephrin-A3 into the skin of neonatal mice markedly accelerated the differentiation process of hair follicles. In addition, injection of ephrin-A3 unexpectedly increased the number of hair follicles.

CONCLUSION: These findings demonstrated that ephrin-A3 not only accelerates anagen development but also increases the density of hair follicles, and also suggested that an ephrin-A-EphA signal pathway is closely involved in hair follicle development.

What the study says is that ephrin-A3 – a signaling protein – is expressed more when the hair follicle is in its growing (anagen) phase and less in its resting (telogen) phase. When this protein is injected into the skin, three things happen: new hair follicles are formed, the hair follicles grow deeper, and hair grows thicker.

The results look promising, but how and when these results can be applied to humans remains yet to be seen.

For more information on hair growth, see these posts:

Asiasari Radix Extract Grows Hair in Mice and in Human Skin Cells
Vitamin E Tocotrienols May Grow Hair in Humans
Green Tea Extract Grows Hair in Vitro, May Work in Vivo
1,000-8,000 mg of MSM Has No Effect on Hair & Nail Growth - Experiment Conclusion