Cardiac precursors in human bone marrow and cord blood: in vitro cell cardiogenesis.
ABSTRACT Cell transplantation has come of age but numerous questions still remain. Which type of cell should be used? Cardiac precursors are present in mouse bone marrow and used to repair the infarcted myocardium in mice. We searched for these precursors in human bone marrow and analyzed gene expression patterns in cells induced to differentiate in vitro.
Cells from human bone marrow were isolated and cultured in medium supplemented with autologous serum and 5% CO2. Cell characterization was performed by immunocytochemical analysis. mRNA was isolated and retrotranscribed. The active genes were detected with polymerase chain reaction by using specific oligonucleotides.
Some inducers pushed the cell through different stages of cardiogenesis, with expression of cardiac transcriptional activators and structural proteins. Some combinations of stimuli were able to drive cells to advanced stages of cardiogenesis.
These studies lead to an exact description of in vitro cardiogenesis in humans. Our aim was also to assess the residual proliferative capacity of cells and to enhance the differentiation efficiency, thus maximizing their repair capacity and the likelihood that they functionally integrate with the surrounding cardiac tissue.
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ABSTRACT: Tissue engineering combines the principles of medical, life science, and engineering fields toward the development of biological substitutes to restore, maintain, or improve tissue function. Previous work has demonstrated the feasibility of bioengineering smooth muscle tissue in vitro; however the contractile properties of bioengineered smooth muscle tissue have not been evaluated. It is imperative that bioengineered tissues have a high degree of functional testing in order to evaluate tissue-specific function as well as suitability for future clinical applications. This research describes the development and functional testing of novel 3-dimensional bioengineered smooth muscle tissues in vitro and the development of a micro-perfusion system to support culture and enhance functionality of bioengineered tissues. All bioengineered tissue models described here were developed utilizing a fibrin biomaterial, which is well-suited for bioengineering contractile tissues. We developed ring-shaped models of rat sphincter and colonic smooth muscle tissue as well as a strip model of human aortic vascular smooth muscle tissue. Functional testing of the contractile properties of bioengineered muscle tissues was accomplished using a custom build force transducer. Bioengineered tissues exhibited striking tissue-specific functionality, which was similar to smooth muscle in vivo, including the generation of spontaneous basal tone and agonist-induced contraction and relaxation, which was calcium-dependent and calcium-independent (respectively). Finally, in order to support the increased metabolic demands of bioengineered tissues, we designed and fabricated a novel micro-perfusion system to promote delivery of a constant supply of oxygenated media to bioengineered tissues. We tested the compatibility of our micro-perfusion system with Bioengineered Heart Muscle (BEHM) and found that the system is capable of supporting viability (mitochondrial activity, total protein, total RNA) and maintaining contractile properties (twitch force, specific force, electrical pacing, and expression of contractile proteins) of bioengineered tissues. In addition, short-term exposure of BEHMs to micro-perfusion resulted in some functional improvement. This research specifically adds to the knowledge base of two critical areas in tissue engineering research: 1) the development of functional bioengineered models, and 2) ancillary technology to support these models. Collectively, this research bridges several scientific and technological gaps in the field of functional tissue engineering. Ph.D. Applied Physics University of Michigan, Horace H. Rackham School of Graduate Studies http://deepblue.lib.umich.edu/bitstream/2027.42/58465/1/lhecker_1.pdf
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ABSTRACT: Cell transplantation promises restoration of cardiac function after myocardial infarction (MI). Comparison of intracoronary cell transplantation with skeletal myoblasts (SMs) versus bone marrow mesenchymal stem cells (BM-MSCs) was carried out in rabbits with MI induced by ligation of the left anterior descending artery. The infarction-affected artery was injected with SMs, BM-MSCs or cell-free medium (control) 24 h post-infarction (n = 15 per group). At baseline, there were no differences in cardiac parameters between the groups. At 4 weeks post-transplantation, left ventricular ejection fraction significantly improved and left ventricular end-diastolic diameter was significantly decreased in the cell-treated groups compared with pre-transplantation and the control group. Engrafted cells were found in all of the cell-treated rabbits. The cell-treated animals had significantly higher numbers of neovessels compared with the control. No significant difference was seen between the SM and BM-MSC groups. In conclusion, intra-coronary transplantation of SMs and BM-MSCs induced neoangiogenesis with comparable enhancements of cardiac performance and reduced cardiac remodelling in a rabbit MI model.The Journal of international medical research 03/2009; 37(2):298-307. · 1.10 Impact Factor
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ABSTRACT: Cardiovascular disease affects 80 million people in the USA and is the leading cause of death. Significant limitations of current treatments necessitate the development of novel strategies. Cardiovascular tissue engineering is an emerging field focused on the development of biological substitutes to restore, maintain, or improve tissue function. In this article, we present an overview of trends in the field and scientific milestones achieved during the last decade. Various 3D bioengineered models of functional cardiovascular structures, including cell-based cardiac pumps, ventricles, patches, vessels, and valves, are described. We discuss critical technological hurdles that must be addressed for continued progress and an outlook for the future of cardiovascular tissue engineering.Journal of Cardiovascular Translational Research 03/2008; 1(1):71-84. · 3.06 Impact Factor