Date of Award

2016

Document Type

Thesis

Degree Name

Master of Biomedical Science

Department

Regenerative Medicine and Cell Biology

College

College of Graduate Studies

Abstract

Tissue vascularization and integration with host circulation remains a key barrier to the successful translation of engineered tissues into clinically relevant therapies. Current efforts to implant large engineered structures are limited by insufficient delivery of oxygen and nutrients, and waste removal. Work presented in this thesis focus on the use of a naturally derived nanofiber for improving molecular interactions between vascular endothelial cells and smooth muscle cells for application to vascular bioengineering. We hypothesize optimization of instructive interactions between vascular cell types can improve formation of microtissue spheroids for application to vascular bioengineering. Toward this goal, I use shortened poly-N-acetyl glucosamine (sNAG) nanofibers to facilitate co‐assembly of pre-vascularized network formation within microtissue spheroids. To gain initial insights into the potential use of sNAG as an instructive biomaterial for vascular tissue regeneration applications, UCB-EPCs, ADSC-VSMCs, and AoAFs were co‐cultured in cell‐aggregates in the presence of sNAG or other known effectors of vascular assembly. Immunofluorescence analysis by confocal microscopy revealed a strong angiogenic effect on EC-only monocultures, which resulted in EC sprout formation, and remodeling in 2D Matrigel assays. When grown in 3D, sNAG nanofibers induced UCB-EPCs migration and increased levels of hPECAM-1 expression, indicative of a fully differentiated EC phenotype. Heterotypic cell cultures show that sNAG nanofibers elicit synthesis of proteins associated with vascular wall assembly and stabilization. An interesting finding of these analyses was that expression of collagen type‐4 was significantly increased in our sNAG treated microtissue spheroids. This increase was greatest in areas of heterotypic cell association, highlighting the importance of cross talk between EPC‐ECs and ADSC‐VSMCs in stimulating synthesis of vascular wall components. Collectively, our preliminary studies suggest that sNAG nanofibers may provide an instructive, biocompatible matrix for assembly of prevascularized microtissue spheroids.

Rights

All rights reserved. Copyright is held by the author.

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