The Angiogenic Properties of the Rat Vibrissa Hair Follicle Associate with the Bulb

Control of hair growth and follicle size by VEGF-mediated angiogenesis

“…Although it has been reported that cultured dermal papilla cells expressed VEGF in vitro (38-40), we consistently did not detect any upregulation of VEGF mRNA expression in the dermal papilla during the murine hair cycle. These findings are in agreement with a previous report that found the angiogenic activity of the rat vibrissa hair follicle associated with the epithelial hair bulb, but not with the mesenchymal hair papilla (9). Moreover, preliminary studies in a transgenic mouse model for overexpression of the green fluorescent protein gene under control of the VEGF promoter (41) detected VEGF promoter activity selectively in follicular outer root sheath keratinocytes, but not in the dermal papilla (data not shown).…”

Nuchal Nevus flammeus and Alopecia areata

“…Moreover NNF is no more recognized as true angioma but as telangiectasia [8,9] maybe, as already reported in portwine stains [10,11], with neurovascular altera tions and with hypotonia of the supportive dermal elements. Further more anagen bulb has angiogenic properties [12] and the nape area, where NNF is located, is certainly a particular site: the sensitivity to topical allergens is higher [13], the anagen period longer and, probably for this [14], the hair regrowth more difficult.…”

Hair Growth in Human Split-Thickness Skin Grafts Transplanted onto Nude Rats: The Role of Ciclosporin

“…Stern et al [7] have recently demonstrated, by using the rabbit corneal-pocket angiogenesis assay and cycled anagen rat vibrissa hair follicles, that the angiogenic stim ulus in hair growth structure is associated with the bulb and not the papillae. Our experiment strengthens the con clusions of Stern et al that the hair follicle itself has the properties to induce its own critical blood supply, and that CS stimulates this.…”