Coronary artery disease is the leading cause of death in industrialized countries. Strategies to treat atherosclerotic coronary artery disease include coronary artery bypass grafting, which is often complicated by vein graft occlusion or stenosis. Severely occluded vein grafts can completely obstruct blood flow to the myocardium, resulting in a myocardial infarction, and eventually lead to heart failure. Heterotopic heart transplantation remains the treatment of choice for end-stage heart failure, however its widespread applicability is limited by the chronic shortage of donor organs. The therapeutic potential of stem cells in cardiac repair following myocardial infarction has generated a great deal of interest. Many types of stem/progenitor cells including embryonic stem cells and bone marrow-derived mesenchymal stem cells (MSCs) have been used to regenerate the infracted heart with promising results. Adipose tissue is an abundant source of multipotent stem cells that can be easily obtained from liposuction waste tissue. The yield of stem cells per gram of fat is higher when compared with marrow-derived MSCs, making adipose tissue an attractive source of autologous stem cells for cardiovascular cell therapies. The goal of this research effort was to examine the differentiation potential of adipose-derived stem cells (ASCs) along the leiomyogenic and cardiomyogenic lineages. ASCs were extracted from human subcutaneous adipose tissue from female donors during elective abdominoplasty, cultured in the presence of biomolecules responsible for vascular and cardiac development, and subjected to uniaxial cyclic strain in magnitudes comparable to the in vivo conditions. Protein and gene expression of smooth muscle- and cardiomyocyte-specific markers were assessed via immunoctytochemistry, Western blot analysis, and RT-PCR. Our results indicated that uniaxial cyclic strain inhibited cell proliferation, resulted in alignment of ASCs perpendicular to the direction of strain, and down-regulated protein expression of early smooth muscle cell markers A-SMA and h1-calponin. Transforming growth factor B1 significantly up-regulated the expression of A-SMA and h1-calponin in ASCs. Cardiac-specific proteins sarcomeric A-actinin, troponin-I, troponin-T were undetected in ASCs exposed to demethylation agent 5-azacytidine. Expression of cardiac transcription factors Nkx2.5 and GATA4 were also absent. These results suggest that human ASCs may not be capable of cardiomyogenic differentiation via exposure to 5-azacytidine.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-11172006-132040 |
| Date | 12 June 2007 |
| Creators | Lee, Wen-Chi Christina |
| Contributors | Partha Roy, Kacey G. Marra, David A. Vorp, J. Peter Rubin |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-11172006-132040/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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