Microvascular changes in relation to inflammation and epidermal hyperplasia in chronic cutaneous lesions of psoriasis vulgaris.

Epidermal proliferation, inflammatory changes and microvascular augmentation are prominent features of chronic cutaneous psoriatic lesions. The objective of this study was the investigation of blood and lymphatic microvascular changes in relation to epidermal changes and inflammatory infiltration in dermis. Immunohistochemical analysis with antibodies to CD34, podoplanin, vascular endothelial growth factors - A and C (VEGF-A and C) and morphometric software were used for quantification of the following parameters: blood and lymphatic vessel area (BVA and LVA), VEGF - A and VEGF-C positive area, inflammatory cell infiltration in dermis (CIA) and epidermal area (EA). In comparison to healthy skin psoriatic lesions showed remarkable elevation of all measured parameters with the following average increase: BVA (2.8-times increased), LVA (2.6-times increased), VEGF-A and VEGF-C area (in epidermis 29-times and 19- times increased, in dermis 25-times and 15- times increased, respectively ), and EA (3-times increased). Statistical analysis revealed significant positive correlation between CIA and EA in psoriatic samples. Blood vessels area and VEGF - A expression in epidermis showed mild positive correlation with epidermal hyperplasia and weak positive correlation with dermal inflammatory infiltration. VEGF - A expression in epidermis also significantly correlated with blood vessels area. As for the lymphatic microcirculation we found a statistically significant positive correlation between lymphatic vessels area and the cellular infiltration in dermis but only weak correlation with epidermal hyperplasia. We hypothesize that angiogenesis in psoriasis is to a greater extent responding to epidermal hyperplasia and in a lesser way to inflammatory infiltration in dermis. However, lymphangiogenesis is significantly related to dermal inflammatory infiltration.