Expression and localization of vascular endothelial growth factor and vascular endothelial growth factor receptor-2 in human epidermal appendages: a comparison study by immunofluorescence

Background.  Vascular endothelial growth factor (VEGF) promotes angiogenesis and plays important roles in neovascularization and development of tissues. VEGF receptors (VEGFRs) are high-affinity receptors for VEGF and are originally considered specific to endothelial cells. We have previously shown that keratinocytes from human normal skin express VEGFRs. This poses the question of whether these receptors are also expressed by epidermal appendages, as epidermal appendages are lined with epithelial cells.
Objective.  To investigate the expression of VEGFR-2 compare with VEGF in epidermal appendages, including hair follicles, eccrine sweat glands and sebaceous glands.
Methods.  Monoclonal antibodies to VEGF and VEGFR-2 were used for immunohistochemical examination of cryostat-cut sections of normal human skin specimens from 11 donors undergoing cosmetic surgery.
Results.  Immunoreactivities for VEGF and VEGFR-2 principally showed parallel intense expression in anagen hair follicle (including outer root sheat, inner root sheath, dermal papillae epidermal matrix), sebaceous glands (ductal and secretory portions) and eccrine sweat glands (ductal and secretory portions), respectively. In particular, abundant expression of VEGF was found in the follicular basement membrane zone surrounding the bulb matrix and in the ductal and secretory portions of eccrine sweat glands.
Conclusion.  A potential VEGF/VEGFR-2 autocrine pathway may be defined by the coexpression of VEGF and VEGFR-2 in human skin epidermal appendages.