Abstract:

Ｏｂｊｅｃｔｉｖｅ：To investigate the phenotypic changes of renal vascular endothelial cells and its relationship with the vascular injury and renal interstitial fibrosis in patients with systemic lupus erythematosus associated thrombotic microangiopathy (SLETMA).
Ｍｅｔｈｏｄｏｌｏｇｙ：Biopsies from thirty SLE patients with lupus nephritis and renal vascular TMA were included in this study. Renal vascular TMA lesions were divided into acute and chronic TMA according to histology by light microscopy. Normal renal tissue from nephrectomized kidney of renal cancer was used as normal control. The expression of renal vascular endothelial CD31, vascular endothelial cadherin (VEcadherin), αsmooth muscle actin (αSMA) and transforming growth factorβ (TGFβ) were stained with immunofluorescence and immunohistochemical assays, and computerassisted image analysis ImageProPlus 60 and ImageScope (Aperio) were used to quantitatively analyze the intensity of endothelial marker expression recorded as the mean density (integral optical density/area of vascular endothelial layer) and the extent of renal interstitial fibrosis respectively.
Ｒｅｓｕｌｔｓ：Confocal immunofluorescence microscopy showed increased expression of αSMA in the vascular endothelial cells in SLETMA, while negative endothelial αSMA expression in normal control．Compared with the normal group, the endothelial expressions of CD31 and VEcadherin were both significantly reduced in acute TMA group (P<005), whereas the expression of αSMA increased significantly (P<001). The endothelial CD31, VEcadherin and TGFβ expressions were significantly lower, while αSMA expression was significantly higher in chronic TMA group than that in other two groups (P<001). The mean density of endothelial αSMA expression was positively correlated with (r=0439，P=0015), while the expression of endothelial CD31 was negatively correlated with the extent of renal interstitial fibrosis significantly (r=-0458，P=0011).
Ｃｏｎｃｌｕｓｉｏｎ：Renal vascular endothelial to mesenchymal transition was found in SLETMA, which was associated with the renal interstitial fibrosis.