Implantation of engineered cardiac tissue may restore lost cardiac function to damaged myocardium. We propose that functional cardiac tissue can be fabricated using a modular, vascularized tissue engineering approach developed in our laboratory. In this study, rat aortic endothelial cells (RAEC) were coated onto sub-millimetre size modules embedded with cardiomyocyte-enriched neonatal rat heart cells (CM) and assembled into a contractile, macroporous sheet-like construct. Cell morphologies, contractility and responsiveness to electrical stimulus were examined to evaluate the function of the resulting modular construct. CM embedded modules contracted spontaneously at day 7 post-fabrication and remained viable in vitro at day 14. Modules cultured in 10% bovine serum were more contractile and responsive to external stimulus compared to 10% FBS medium cultured modules. VE-cadherin staining showed a confluent layer of RAEC on CM embedded co-culture modules at day 7. Co-culture modules were also contractilie, but when compared to CM only modules their electrical responsiveness was slightly diminished. Modules assembled into macroporous sheets retained their characteristics at day 10 post-assembly. Micrographs from histological sections revealed the existence of muscle bundles near the perimeter of modules and at inter-module junctions. The fate of modular cardiac tissues in vivo was examined using two implantation strategies based on a syngeneic animal model. Co-culture modules (CM and EC) were either injected into the peri-infarct zone of the heart, or fabricated into a patch form and implanted over a right ventricular free wall defect. In both models, donor EC were involved in the formation of blood vessels-like structures, which appeared to have connected with the host vasculature. Co-culture implants had a higher overall vessel density compared to CM-only implants, but only in the absence of MatrigelTM. Moreover, donor CM organized into striated muscle-like structures, at least when MatrigelTM was removed from the matrix. Together these results suggest that modular cardiac tissue can survive and develop into native-like structures when implanted in vivo and the potential of the modular approach as a platform for building 3-D vascularised cardiac tissue should be explored in greater depth.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/30037 |
| Date | 14 November 2011 |
| Creators | Leung, Brendan Martin Pue-Bun |
| Contributors | Sefton, Michael |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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