The Expression Of VEGF-A,MCP-1 And RANTES At Venous Stenosis Of Arteriovenous Fistula In Hemodialysis Patients

Objective: Arteriovenous fistula(AVF)is the most preferred vascular access for hemodialysis patients.However,it is yield to high failure ratio.Neointimal hyperplasia of juxta-anastomotic venous segment that contributes to AVF stenosis is the single most important cause of AVF primary failure.The fundamental histological characteristic presents unchecked smooth muscle cellular proliferation with angiogenesis and extracellular matrix deposition.The exact mechanisms leading to neointimal hyperplasia are not fully understood,however,experimental and clinical studies revealed that various cytokines were implicated in the process.VEGF-A is a cytokine which stimulates proliferation and migration of endothelial cells and smooth muscle cells.It is associated with the recruitment of monocytes or macrophages.What's more,VEGF-A is important in vascular remodeling and restenosis.Inflammation plays an important role in the formation of AVF stenosis.While MCP-1 has the following effects: potent chemotaxis of monocytes and macrophages to the inflammatory sites;promotion of proliferation and migration of smooth muscle cells.In addition,it contributes to angiogenesis and is involved in the vascular remodeling and inflammatory disease.RANTES is known for its role in the homing and activation of inflammatory cells and is therefore involved in targeting inflammatory cell recruitments into damaged or inflamed tissue.The pro-angiogenic role of RANTES is important.To investigate the relationship between VEGF-A,MCP-1 as well as RANTES and neointimal hyperplasia at arteriovenous fistula,we detect the expression of VEGF-A,MCP-1 and RANTES at venous stenosis of arteriovenous fistula in hemodialysis patients.Methods: 28 patients were involved,all of whom were diagnosed with end stage renal disease and regular maintenance hemodialysis.The experimental group including 14 patients who were referred for the reconstruction of failing arteriovenous fistula resulting from juxta-anastomotic stenosis,while others considered as the control group were referred for their first operation of AVF.Approximately 1cm abandoned hyperplastic vein was collected from each patient in the experimental group during the revision,while 0.5-1cm vein was collected from venous side intended to be anastomosed to the artery in the control group during the creation of AVF.All of the vein specimens were stained with hematoxylin and eosin,and immunohistochemical staining was performed.Finally,we observed the sections under light microscope.All data was analyzed by statistical analysis software SPSS 21.0 and expressed as mean ± SE(x±s).Probability values less than 0.05 were required for statistical significance.Results: 1 Clinical characteristics of two groupsWe made a comparison between the two groups,they were statistically similar in age,gender and primary disease for end stage kidney disease(p>0.1).2 HE stainingA noteworthy neointimal hyperplasia,inflammatory cell infiltration and angiogenesis was observed in the sections from the experimental group,while little neointimal hyperplasia,inflammatory cell infiltration and angiogenesis were found for the control group.The mean ratio of intima thickness /media thickness was significantly higher in the experimental group than the control group.There was also an obviously increase in the neointima area/media area ratio in the experimental group when compared to the control group.Significant difference was related to both of them(p<0.001).3 Immunochemistry staining 3.1 VEGF-A immunochemistry staining VEGF-A was located in the cytoplasm.Strongly positive staining was observed in the intima and media in the sections from experimental group,while weakly positive staining was found in the intima and media in the sections from control group,especially in the intima.The analysis revealed that there was significant difference in VEGF-A protein expression between experimental and control group(p<0.01).3.2 MCP-1 immunochemistry staining MCP-1was located in the cytoplasm.Strongly positive staining in the intima and media were observed in the sections from experimental group,while weakly positive staining was found in the intima and media in the sections from control group,especially in the media.The analysis revealed that there was significant difference in MCP-1 protein expression between experimental and control group(p<0.01).3.3 RANTES immunochemistry staining RANTES was located in the cytoplasm.Strongly positive staining in the intima and media were observed in the sections from experimental group,while weakly positive staining was found in the intima and media in the sections from control group.The analysis revealed that there was significant difference in RANTES protein expression between experimental and control group(p<0.01).3.4 Negative control for immunochemistry staining No positive staining was observed in the intima and media.Claybank was found in the adventitia without positive cells.We considered it as nonspecific staining.Conclusions1 Increased expression of VEGF-A,MCP-1 and RANTES is related to venous intima hyperplasia of AVF in hemodialysis patients,they may be the therapeutic target for the future.2 VEGF-A may induce the expression of MCP-1 which in turn mediates the expression of RANTES,Finally,they contribute to the intima hyperplasia of AVF.3 VEGF-A may induce the expression of MCP-1 and RANTES.Then they contribute to the intima hyperplasia of AVF.