Clinicopathological Significance Of Expression Of VEGF And MMP-2 And TIMP-2 In Psoriatic Lesions

Psoriasis is histologically characterized by keratinocyte hyperproliferation, infiltration of inflammatory cells, neoangiogenesis. Angiogenesis is necessary during psoriasis occurrence and development, investigation about its role in psoriatic pathogenesis is the more and more paid attention to. Angiogenesis is regulated by certain stimulators and inhibitors. Vascular endothelial growth factor (VEGF) is a most typical mitogen of endothelial cells and a potent angiogenesispromoting factor. Recent reports reveal that VEGF is a crucial angiogenic factor in process of psoriatic angiogenesis. Matrix metalloproteinase 2 (MMP-2) is a protease that degrade specifically type IV collagen, the main structural component of the basement membrane and matrix. Tissue inhibitors of metalloproteinase 2 is specifically for inhibiting MMP-2. Both of them play an important role in psoriatic angiogenesis.Objective: The aim of this study is to evaluate expressions of VEGF,MMP-2 and TIMP-2 as well as the correlation with them and angiogenesis in psoriasis,in order to reveal psoriatic pathogenesis and to provide help for anti-angiogenesis therapy of psoriasis.Materials and methods: 30 cases of involved psoriatic skin, 12 cases of uninvolved psoriatic skin, 12 cases of normal control skin in the same of locus are selected. All the tissues were fixed in 10% neutral formalin and desiccated and embedded in paraffin. Irnrmmohistochemical streptavidin peroxidase conjugate method was used to analyze the VEGF,MMP-2 and TIMP-2 expression in involved psoriatic skin, uninvolved psoriatic skin and normal nonpsoriatic skin. Statistical analysis wasperformed with SPSS 11.0 software, using Chi-square and Fisher's exact probability test. Statistically significant difference was considered as "a =0.05 " .Results:1 The results of VEGF expression: VEGF was stained in the cytoplasm of keratinocyte except honey layer cell. It was not expressed in normal skin. VEGF-positive rates were 73.3%(22/30) in involved psoriatic skin and 25.0%(3/12) in uninvolved skin. The former was significant higher than the latter and that was in normal skin. (p<0.05). There were no significant difference between them in uninvolved and normal skin(p>0.05).2 The results of MMP-2 expression: MMP-2 was stained in the cytoplasm of keratinocyte in basal layer and superbasal layer. MMP-2 was not expressed in uninvolved and normal skin. MMP-2-positive rates in the involved psoriatic skin was 50.0%(15/30), it was significant higher than that was in uninvolved and normal skin(p<0.05).3 The results of TIMP-2 expression: TIMP-2 was stained in the cytoplasm of keratinocyte in basal layer and superbasal layer. TIMP-2 was not almost expressed in normal skin. TIMP-2-positive rates were 23.3%(7/30) in involved psoriatic skin and 25.0%(3/12) in uninvolved skin. There were no significant difference between them(p>0.05).4 The association of VEGF and MMP-2 expression in involved psoriatic skin. VEGF expression was positively correlated with MMP-2 expression in involved psoriatic skin.5 The association of MMP-2 and TIMP-2 expression in involved psoriatic skin. MMP-2 expression was negatively correlated with TIMP-2 expression in involved psoriatic skin.6 The association of VEGF and TIMP-2 expression in involved psoriatic skin. VEGF expression was negatively correlated with TIMP-2 expression in involved psoriatic skin.Conclusions:1 VEGF expression enhances significantly in psoriatic leision, but it is notexpressed in normal skin and uninvolved skin, which indicates that VEGF may be an important enhancing factor in psoriatic angiogenesis.2 MMP-2 expression enhances significantly in psoriatic leision, but it is not expressed in normal skin and uninvolved skin, which indicated that MMP-2 may promote psoriatic angiogenesis.3 Unbalance of expression between MMP-2 and TIMP-2 plays an important role in psoriatic angiogenesis.4 There is a correlation between VEGF and MMP-2, which suggests that bot...