Periadventitial Delivery of Nanoparticle-Encapsulated AZD8797 Reduces Venous Stenosis in a Murine Arteriovenous Fistula Model

Background: Venous neointimal hyperplasia (VNH) and venous stenosis (VS) decrease the patency of arteriovenous fistulas (AVFs) for hemodialysis. Immune cell infiltration drives VNH/VS, with the CX3C motif chemokine receptor 1 (CX3CR1) playing a key role in leukocyte adhesion and migration. This study evaluates if the peri-adventitial delivery of nanoparticle encapsulated AZD8797, a CX3CR1 inhibitor, immediately after AVF creation prevents VNH/VS in a murine AVF model with established chronic kidney disease (CKD). Methods: Thirty-six male C57BL/6J mice (7-8 weeks old, weighing 26.42 ± 0.29 g) underwent partial nephrectomy to induce CKD. AVFs were created 28 days later, and the mice received peri-adventitial delivery of PLGA nanoparticles in 20% Pluronic F127 hydrogel only (NP C) or the same formulation with AZD8797 (AZD8797 NP) on the outflow vein (GV). Three days post-AVF, 20 mice were sacrificed for the drug dose study, while 16 mice underwent weekly Doppler scans and were sacrificed 28 days post-AVF for histomorphometry and immunohistochemical evaluations. Results: Drug response study showed that 50 µM AZD8797 NP significantly reduced CX3CR1 gene expression in GV. AZD8797 NP group exhibited significantly higher peak systolic velocity, wall shear stress, and blood flow, with histomorphometric analysis showing an increase in average lumen vessel area. (32,282.67 ± 4,770.40 μm2 vs. 7,983.80 ± 1,695.85 μm2, p=0.0027) and reduced neointimal cell density (0.0047 ± 0.0006 cells/μm2 vs. 0.0092 ± 0.0012 cells/μm2, p=0.0107). AZD8797 NP group showed decreased immune markers CX3CR1 (5.15 ± 1.11 vs. 15.45 ± 1.02, p=0.0001), CX3CL1 (2.78 ± 0.45 vs. 9.63 ± 1.23, p=0.0028), CD68 (4.78 ± 0.88 vs. 12.71 ± 1.19, p=0.0008) and NF-κB (1.88 ± 0.56 vs. 5.43 ± 0.37, p=0.0011) expression. Smooth muscle and fibroblast staining were significantly decreased in the AZD8797 NP group (α-SMA: 5.44 ± 0.57 vs. 19.15 ± 0.53, p=0.0015; FSP-1: 11.22 ± 0.78 vs. 16.79 ± 1.36, p=0.0117). Ki67 staining was significantly decreased (5.16 ± 0.83 vs. 8.40 ± 0.72, p=0.0229) with increased TUNEL assay in the AZD8797 NP group (2.04 ± 0.23 vs. 0.88 ± 0.19, p=0.0149). Conclusion: Peri-adventitial delivery of AZD8797 NPs significantly reduces VNH/VS with improved vascular remodeling. This approach shows promise as a therapeutic strategy to enhance AVF patency. Funding: NIDDK Support - NIDDK Support, NIDDK Support