Abstract: Objective To evaluate the influence and mechanism of hypertensive nephropathy and diabetic nephropathy on neointimal hyperplasia in autologous internal arteriovenous fistula (AVF) in maintenance hemodialysis (MHD) patients. Methods Cephalic veins were collected during the surgery of AVF angioplasty or reconstruction for MHD patients. The samples were divided into chronic glomerulonephritis group, hypertensive nephropathy group and diabetic nephropathy group based on primary disease of the patients. Histological changes were examined and the thickness of intima and media was measured after H-E staining of the sample. Immunohistochemistry was used to detect the expression of several growth factors in vascular tissue. The correlation between α-SMA and growth factors was then analyzed. Results Intima thickness increased more in hypertensive nephropathy and diabetic nephropathy groups than in chronic glomerulonephritis group. Immunohistochemical staining showed that α-SMA, bFGF, IGF-1 and MMP-9 increased significantly after the surgery for 12-18 months in hypertensive nephropathy and diabetic nephropathy groups. In contrast, VEGF reduced significantly, and MMP-2 had no changes. Univariate regression analysis revealed that α-SMA level was positively correlated with the levels of bFGF, IGF-1 and MMP-9, and negatively correlated with the level of VEGF in vascular tissue. Conclusions Proliferation of vascular smooth muscle cells (VSMCs) was the leading cause of intima hyperplasia in MHD patients. The up- regulation of bFGF, IGF- 1 and MMP-9 and down-regulation of VEGF in vascular tissue may relate to the VSMCs proliferation. Hypertension and diabetes
can accelerate the processes of intima hyperplasia and shorten the life of fistula, especially in MHD patients with diabetes.

Key words: Vascular access, Autologous arteriovenous fistula, Intimal hyperplasia, Hypertension, Diabetes