Vascular endothelial growth factor 121 is the predominant isoform in psoriatic scales

Vascular endothelial growth factor (VEGF) is a powerful agent that causes hyperpermeability of blood vessels as well as endothelial cell proliferation. Recent investigations have revealed that production of VEGF increases in epidermis of psoriatic lesions, and the overproduced VEGF plays an important role in the pathogenesis of psoriasis. In this study, we used immunohistochemical staining as well as extraction of stratum corneum with physiological saline to further analyse VEGF produced in psoriatic lesions. Biological activity of VEGF in the psoriatic scales was assayed by cultured human umbilical vein endothelial cells in vitro. The immunohistochemical examination confirmed an increased production of VEGF in the keratinocytes of psoriatic lesions. In addition, we found that the content of VEGF contained in the psoriatic scales was approximately 50 times greater than that in normal stratum corneum. We also found that VEGF 121 isoform, which has an exclusive ability to cause hyperpermeability of blood vessels, was predominantly detected in psoriatic scales, suggesting a major role of VEGF 121 isoform on the altered structure of microvessels in psoriatic lesions.