Paracrine cross-talk between human hair follicle dermal papilla cells and microvascular endothelial cells.

Exp Dermatol. 2015 Feb 18. doi: 10.1111/exd.12670. [Epub ahead of print]
Paracrine cross-talk between human hair follicle dermal papilla cells and microvascular endothelial cells.
Bassino E1, Gasparri F, Giannini V, Munaron L.

Human follicle dermal papilla cells (FDPC) are a specialized population of mesenchymal cells located in the skin. They regulate hair follicle (HF) development and growth, and represent a reservoir of multipotent stem cells 1 ,2 . Growing evidence supports the hypothesis that HF cycling is associated with vascular remodeling 3 . Follicular keratinocytes release vascular endothelial growth factor (VEGF) that sustains perifollicular angiogenesis leading to an increase of follicle and hair size 3 . Furthermore, several human diseases characterized by hair loss, including Androgenetic Alopecia, exhibit alterations of skin vasculature 4,5,6 . However, the molecular mechanisms underlying HF vascularization remain largely unknown 7 . In vitro co-culture approaches can be successfully employed to greatly improve our knowledge and shed more light on this issue. Here we used Transwell-based co-cultures to show that FDPC promote survival, proliferation and tubulogenesis of human microvascular endothelial cells (HMVEC) more efficiently than fibroblasts. Accordingly, FDPC enhance the endothelial release of VEGF and IGF-1, two well-known proangiogenic growth factors. Collectively, our data suggest a key role of papilla cells in vascular remodeling of the hair follicle.