Chronic kidney disease nor stromal cell-derived factor 1a peptide (sdf-1a) bio-functionalization alter rodent vascular in situ tissue formation

Abstract Background and Aims The systemic pro-inflammatory environment of chronic kidney disease (CKD) could influence neo-tissue formation of in situ tissue engineered vascular access grafts. Here, we studied in-graft tissue formation and inflammation in a rat CKD model. Moreover, we explored graft bio-functionalization with stromal cell-derived factor 1α peptides (SDF-1α), a progenitor cell chemotactic which may improve cell engraftment. Method Pristine or SDF-1α bio-functionalized vascular grafts (1,2 mm ID, 2 cm length, 250–300 μm wall thickness) were created from biodegradable, polycarbonate-bisurea (PC-BU) electrospun meshes. Abdominal aorta interposition grafts were implanted in female Sprague Dawley rats (n = 53) that underwent sham surgery or CKD induction by 5/6th nephrectomy. Explanations and analyses were performed after two (n = 25) or twelve (n = 9) weeks. Results At two weeks, survival and graft patency were 100%. Explant cellularity and collagen content were not significantly different between sham and CKD rats and were not influenced by SDF-1α. Endothelial cell coverage (RECA+) and smooth muscle cell presence (αSMA+) were visually similar irrespective of disease or bio-functionalization. Elastin+ (p = 0,11), pan-(CD68+, p = 0,08) and anti-inflammatory macrophage (CD163+, p = 0,52) surface area, as well as (anti-)inflammatory gene expression were not significantly different between groups. The twelve-week CKD-group was taken out of experiment prematurely due to rapid disease progression. In addition, preliminary death due to vascular rupture occurred in four animals (n = 2 pristine and n = 2 SDF-1α) in the twelve-week sham animals. While patent, all remaining sham explants at twelve weeks (n = 9) showed severe vascular dilatation and calcifications (Von Kossa+). No differences in inflammatory and neo-tissue markers were found between twelve-week sham pristine and SDF-1α grafts or between explants over time. Conclusion CKD did not significantly alter inflammation or tissue formation of in situ tissue engineered vascular grafts. Additionally, SDF-1α bio-functionalization did not significantly alter cell engraftment or tissue formation. Mechanical stability of the graft appears to be the primary driver of neo-tissue formation. Future emphasis on in vitro to in vivo translation should be on the fine balance between tissue formation on one hand and fiber resorption on the other hand.