Abstract: SA-OR020
IRS-1/KLF-4-Mediated Vascular Smooth Muscle Cells Differentiation Is Critical for Arteriovenous Fistula Maturation in a Mouse Model
Session Information
- Dialysis Vascular Access: From Basic Discovery to Translational Science
November 08, 2025 | Location: Room 342D, Convention Center
Abstract Time: 04:40 PM - 04:50 PM
Category: Dialysis
- 803 Dialysis: Vascular Access
Authors
- Xi, Gang, The University of North Carolina at Chapel Hill Kidney Center, Chapel Hill, North Carolina, United States
- Wai, Christine, The University of North Carolina at Chapel Hill Kidney Center, Chapel Hill, North Carolina, United States
- Uriyanghai, Unimunkh, The University of North Carolina at Chapel Hill Kidney Center, Chapel Hill, North Carolina, United States
- Yang, Anthony Zhi, The University of North Carolina at Chapel Hill Kidney Center, Chapel Hill, North Carolina, United States
- Li, Lianxia, The University of North Carolina at Chapel Hill Kidney Center, Chapel Hill, North Carolina, United States
- Bahnson, Edward Moreira, The University of North Carolina at Chapel Hill Kidney Center, Chapel Hill, North Carolina, United States
- Roy-Chaudhury, Prabir, The University of North Carolina at Chapel Hill Kidney Center, Chapel Hill, North Carolina, United States
Background
We previously reported that insulin receptor substrate-1 (IRS-1) is required to maintain differentiation of vascular smooth muscle cells (VSMCs) via regulating KLF-4/P53 complex formation. High glucose or IRS-1 knockout (KO) decreased p53 levels resulting in decreased association of p53 with KLF-4. However, these studies were performed in aortic VSMCs only. In this study, we generated IRS-1 smooth muscle (SM) specific KO mice and created arteriovenous fistula (AVF) to study the functions of IRS-1 in AVF maturation in a mouse model.
Methods
Aged 14-16 weeks of IRS-1 SM KO mice were used to create AVF following an established protocol. An end-to-side anastomosis was created between the jugular vein and carotid artery. High-resolution micro-computed tomography (micro-CT) was performed in vivo on days 21 post-surgery. After imaging, animals were sacrificed and AVF tissues were collected for histological analysis and IHF staining.
Results
CT images of AVF section showed severe vessel narrow down in both venous segment and arterial segment of AVF (highlighted) (Figure 1 right panel), compared to the same location in wild type (WT) animal (left panel). HE staining results clearly showed the severe blockage caused by neointimal hyperplasia and/or thrombus in venous segments from anastomosis to around 800 um distal position. In addition, IHF staining confirmed the KO IRS-1 signal in SM only but not in endothelial cells and adventitia. Further, like observations obtained from diabetic animals, KLF-4 expression in VSMCs was dramatically increased when IRS-1 was knockout in SM.
Conclusion
Eliminating IRS-1 in SM significantly enhanced neointimal hyperplasia in venous segments of AVF. Our results support the hypothesis that the previously described inhibition of IRS-1 in the setting of diabetes or uremia could be the pathway responsible for the more aggressive AVF stenosis that likely occurs in these clinical settings.
Figure 1. CT scan images of AVF in wild type (WT) mouse and IRS-1 smooth muscle (SM) knockout (KO) mouse
Funding
- NIDDK Support