Date of Award

5-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biomedical and Chemical Engineering and Sciences

First Advisor

C. Bashur

Second Advisor

J. R. Brenner

Third Advisor

C. Martino

Fourth Advisor

T. Conway

Abstract

Current surgical alternatives for treating coronary artery diseases are limited in patients with systemic vascular diseases due to unavailability of suitable autologous vessels. The overall goal of this research project is to develop an appropriate tissue engineered vascular grafts (TEVGs) for small-diameter (<6 mm) arteries. Current grafts fail from intimal hyperplasia, caused by hyperproliferation of the smooth muscle cells (SMCs), and graft thrombosis, caused by lack of functional endothelium. Formation of the endothelium, and production of pro-inflammatory species that limits the long term patency, are partially due to the accumulation of oxidized lipid species. In this study, the scaffold composition was systematically varied to assess the inflammatory response and lipid oxidation levels in a rat peritoneal model. Specifically, we determined the collagen to PCL ratio required to limit the production of pro-inflammatory species, while maintaining the required mechanical strength for vascular grafts. Electrospun conduits were prepared from 0%, 10%, and 25% blends of collagen/ PCL (w/w) and implanted in the rat peritoneal cavity for 4 weeks. The results of the study showed that scaffold composition can be varied while keeping the fiber diameter similar. Results from 10% blend conduits showed significantly higher expression for contractile markers compared to the 25% and 0% blend conditions. In general, adding collagen to the PCL conduits reduced the accumulation of oxidized species within the implanted conduits. All conduits exhibited sufficient tensile strength post- implantation. In conclusion, these results demonstrate that introducing 10% collagen into electrospun scaffolds limits the pro-inflammatory characteristics of the recruited peritoneal cells that can potentially improve patency of the TEVGs.

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