Introduction of elastin into polymeric system for aneurysm repair
An abdominal Aortic Aneurysm (AAA) is a dilation of the infrarenal aorta of at least 150%. This disease represent a significant problem for older male individuals, and current leading treatments, such as endovascular repair, are insufficient due to complications such as endoleaks. A tissue-engineered approach to aneurysm repair has been previously introduced whereby a bioresorbable synthetic polymer is electrospun into a tubular structure resembling the shape of the aorta. Once implanted, this device establishes a new lumen for blood flow, while also recruiting cells from the surrounding tissue. The present work focused on the inclusion of elastin into the polymeric system. Elastin is found in the vasculature, where it constitutes up to 57% of the dry weight of arteries like the aorta. This protein allows arteries to expand without damage, and also serves as an attachment point for cells. The presence of elastin was hypothesized to improve the mechanical properties while also providing a more cell-friendly surface. Elastin was dissolved in hexafluoroisopropanol along with polycaprolactone. Various electrospinning parameters and elastin concentrations were investigated to find a variable set which could produce scaffolds with optimal mechanical properties, fiber morphology, and cellular response. 10% elastin scaffolds had high strength and strain values and low stiffness. Scaffolds electrospun at 15 cm tip-to-collector distance exhibited more consistent fiber morphology. Smooth muscle cells (SMCs) seeded onto the scaffolds showed no difference in metabolic activity. The results of this work indicate that elastin is a viable addition to the polymeric system, based upon mechanical, morphological, and in vitro cellular data.