Increased expression of the P2Y₁₂ receptor is involved in the failure of autogenous arteriovenous fistula caused by stenosis

This study investigated the role of the P2Y₁₂ receptor in autogenous arteriovenous fistula (AVF) failure resulting from stenosis. Stenotic venous tissues and blood samples were obtained from patients with end-stage renal disease (ESRD) together with AVF stenosis, while venous tissues and blood samples were collected from patients with ESRD undergoing initial AVF surgery as controls. Immunohistochemistry and/or immunofluorescence techniques were utilized to assess the expression of P2Y₁₂, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein 1 (MCP-1), and CD68 in the venous tissues. The expression levels of P2Y₁₂, TGFβ1, and MCP-1 were quantified using quantitative reverse transcription–polymerase chain reaction and western blot analyses. Double and triple immunofluorescence staining was performed to precisely localize the cellular localization of P2Y₁₂ expression. Expression levels of P2Y₁₂, TGFβ1, MCP-1, and CD68 were significantly higher in stenotic AVF venous tissues than in the control group tissues. Double and triple immunofluorescence staining of stenotic AVF venous tissues indicated that P2Y₁₂ was predominantly expressed in α-SMA-positive vascular smooth muscle cells (VSMCs) and, to a lesser extent, in CD68-positive macrophages, with limited expression in CD31-positive endothelial cells. Moreover, a subset of macrophage-like VSMCs expressing P2Y₁₂ were observed in both stenotic AVF venous tissues and control venous tissues. Additionally, a higher number of P2Y₁₂⁺/TGF-β1⁺ double-positive cells were identified in stenotic AVF venous tissues than in the control group tissues. Increased expression of P2Y₁₂ in stenotic AVF venous tissues of patients with ESRD suggests its potential involvement in the pathogenesis of venous stenosis within AVFs.