Abstract 1130: Tenascin-C In Arteriovenous Fistula Failure: Unraveling Venous Remodeling Dynamics

Abstract

Background: AVF are the preferred vascular access for hemodialysis, with superior patency and lower infection rates than grafts or catheters. Nevertheless, AVF patency is reduced by both early thrombosis and NIH, culminating in diminished utilization due to one-year patency rates as low as 40-50%. Tenascin-C (TnC), an ECM glycoprotein with limited adult expression, is transiently present at sites of tissue injury and inflammation. TnC has been implicated in playing a role in the development of NIH. Hypothesis: Sustained TnC expression contributes to NIH, potentially leading to AVF failure. Methods: Female and male wild-type C57Bl/6 mice, aged 9-11 weeks, had sham surgery or AVF creation by puncturing the infrarenal aorta into the inferior vena cava (IVC) with a 25-gauge needle. Doppler ultrasound confirmed AVF presence. Tissue samples were collected for IF, WB, and qPCR. Human matched vein and AVF tissue were obtained from patients undergoing planned two-stage AVF creation surgeries and analyzed with IF. In vitro analysis of human dermal microvascular endothelial cells (HDMEC) was performed to investigate the role of TnC in thrombomodulin expression. Results: TnC expression significantly increased in the AVF by day 7, returning to baseline by day 21 and reaching negligible levels by day 42. The spatial and temporal regulation of TnC expression post-AVF creation correlated with ECM remodeling and inversely with thrombomodulin. Both mice and human studies demonstrated differential regulation of TnC and thrombomodulin in patent and occluded AVF. In HDMEC, TnC knockdown suppressed NF-kB expression and increased thrombomodulin expression, while exogenous TnC had the opposite effect. Conclusion: TnC plays a pivotal role in driving pathological inflammation, with its expression being both temporally and spatially regulated during venous remodeling post-AVF creation. Persistent TnC expression is noted in occluded mouse and human AVF, leading to decreased thrombomodulin expression and heightened thrombogenicity. Sustained TnC expression regulates the shift from physiological to pathological venous remodeling, underscoring the crucial role of the immune response in this process and highlighting potential translational therapeutic strategies.