Project Summary A huge and unmet clinical need is associated with hemodialysis vascular access dysfunction, which is currently considered to be one of the most challenging forms of clinical vascular grafting. The high failure rates associated with all types of dialysis vascular access, including arteriovenous fistulae and arteriovenous graft, result in significant morbidity, mortality and economic cost. Despite the magnitude of this clinic problem, no effective solutions are available. The end-stage renal disease and other health conditions of hemodialysis patients present a hostile milieu, such as uremia, inflammation and flow disturbance caused by small and/or non-compliant vessel, around the vascular access, which account for, at least partially, the access failure. The central hypothesis for this proposal is that precision cell niches, developed under hemodialysis-relevant conditions and when applied to the clinical setting of dialysis vascular access, prevent dialysis access failure. To test this hypothesis, we will introduce cell-protective, regenerative signals in the precision cell niches, which functionalize mesenchymal stem cells (MSCs) to override the hostile milieu impact and orchestrate the arterial regeneration, leading to patent, robust vascular access. This project will use our novel biomaterials platform, which allows both the cell niche and the niche-containing structure to be tailored using clinical inputs such as uremia, blood flow, vessel compliance and diameter, with a goal of optimizing targeted arterial regeneration to reduce access failure. To pursue the research goal, three aims are proposed here. AIM 1 focuses on incorporating the precision cell niches into a peri-vascular wrap and determining its effect on the arterialization of arteriovenous fistula under simulated hemodialysis conditions. AIM 2 seeks to establish and spatially integrate distinct precision cell niche designs to promote arteriovenous graft arterialization. AIM 3 will evaluate how the precision niche design can assist MSC-based arterial regeneration for vascular access in a diseased swine model. If successful, the precision vascular access platforms developed here could transform traditional clinical care paradigms for dialysis vascular access. We envision that in the near future, nephrologists could have the access to a range of vascular access devices derived from precision cell niche designs.

Public Health Relevance Statement Vascular access is the lifeline of hemodialysis patients. Hemodialysis access dysfunction is considered to be one of the most challenging forms of clinical vascular grafting. This project aims to develop a novel hemodialysis access platform that uses mesenchymal stem cells in precisely defined physical, chemical, structural and biological microenvironments, with the goal of regenerating arterial tissues for successful hemodialysis access.