Date of Award

12-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Bioengineering

Committee Member

Dr. Agneta Simionescu, Committee Chair

Committee Member

Dr. Dan Simionescu

Committee Member

Dr. Sarah Harcum

Abstract

Myocardial infarction (MI) is one of the leading causes of death associated with cardiovascular disease affecting approximately 735,000 Americans each year. The resulting damage caused by MI initiates a pathological progression towards congestive heart failure. Donor shortages rule out transplantation as a viable treatment option and coronary revascularization does not solve the issue of regenerating the infarct scar. Stem cell therapies, however, show great potential, but have been largely unsuccessful at regenerating diseased myocardium. This study aims to differentiate human adipose derived stem cells (hADSCs) by methods of co-culture and chemical induction to produce functional cardiomyocytes, as well as by mechanical and electrical stimulation in a bioreactor. Ultimately, pre-differentiated cardiomyocytes could be implanted into diseased patients in order to provide a functional myocardial patch. Chemical induction of hADSCs by a DNA methylation inhibitor, 5-Azacytidine, produced differentiated cardiomyocytes that expressed cardiac-specific desmin, a type III muscle intermediate filament that regulates sarcomere architecture. ADSCs were also co-cultured with human embryonic stem cell derived cardiomyocytes on well plates in order to induce the differentiation of hADSCs towards cardiomyocytes. Co-cultured cells expressed cardiac-specific troponin T, cardiac myosin heavy chain, alpha-actinin, and desmin. Although the co-cultured cells did express myocyte markers, these cells did not express significantly more protein than the hESC cardiomyocytes cultured alone. These findings suggest that this method of differentiating hADSCs may not be a clinically viable option. Further, decellularized porcine myocardium was used as a scaffold to seed hADSCs in a bioreactor and was introduced to both mechanical and electrical stimuli to simulate physiological conditions. After 3 weeks of culture, the myocardial patches were analyzed for cardiac-specific proteins and were confirmed to express all of the previously tested markers. The myocardial patches did not allow for good cell infiltration into the tissue so further seeding tests need to be conducted to optimize cell penetration. Future studies will integrate the co-culture method as well as the chemical treatment method with the bioreactor to optimize the differentiation of hADSCs towards cardiomyocytes.

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