Jonathan Bomar1, Scott Collins Ph.D1,2, and Rosemary Smith Ph.D1,3 ENGINEERING CARDIAC TISSUE REPAIR AND REGENERATION Jonathan Bomar1, Scott Collins Ph.D1,2, and Rosemary Smith Ph.D1,3 1 GSBSE, 2 Department of Chemistry, 3Electrical and Computer Engineering, University of Maine Abstract Results Future Directions Each year, nearly one million Americans have a heart attack (myocardial infarction, MI). Patient outcomes are highly variable, but all suffer some loss of cardiac function due to permanent tissue damage. This seed project is an interdisciplinary collaboration between the University of Maine (UMaine) and Maine Medical Center Research Institute (MMCRI) that aims to develop cardiac tissue regeneration and repair strategies at the molecular and cellular level. This research initiative will apply recent advancements at UMaine in microsystems engineering to direct the differentiation of embryonic stem cells into complex spatially-organized tissue in vitro. Combined with translational research performed at MMCRI, this exciting new biotechnology aims to a) enable new, competitive research grants, b) translate research to new clinical therapies, c) create new commercial opportunities for Maine’s health care and medical products industry, and d) ultimately establish Maine as a center of excellence for MI research and therapy. Figure 2: Day 21 in differentiation media. The panel on the left shows a phase contrast image of the culture in a 12 well-plate. The panel on the right shows a fluorescence image of the same culture. Red: MF20 staining of cardiomyocytes. Green: anti-vimentin staining of mesenchymal cells. Methods Figure 5: Depiction of possible microfluidic device for diffusion-based study of cardiac tissue development and regeneration. Citation below. We will explore this culture technique in the context of a microfluidic device. One major advantage of our culture technique is that cardiomyocytes develop in predictable regions in the culture We can pattern diffusion ports into the device to produce localized spikes of chemical cues related to development or tissue injury We can also pattern microelectrodes for electrophysiological studies, allowing us to selectively stimulate cardiomyocytes before they show spontaneous contractile activity Microdevices will also allow us to pattern the shape of the culture We can explore the role of shape-dependent differentiation of cardiomyocytes, giving clues about the role of morphogen gradients in development4 Mouse embryonic stem cells (mESCs) were suspended in a three-dimensional hydrogel matrix. Cells were cultured in differentiation medium for 12+ days. Spontaneous beating of the myocytes began on day 11 in differentiation media. Time-lapse phase contrast imaging was conducted over a period of 12 days to explore the development of mESCs into cardiac tissue. Immunocytochemistry was performed to determine what cell types are present in the culture at different time points Figure 3: Day 21 in differentiation media. The panel on the left shows a phase contrast image of the culture in a 12-well plate. The panel on the right shows a fluorescence image of the same culture. Red: staining of smooth muscle actin. Green: CD31 staining of endothelial cells. Spontaneous beating begins on approximately day 10.5 in culture and can last until at least day 30 in culture. The contracting cells form a connected network that surrounds the central region of the culture. The contracting cells are responsive to electrical stimulation. Works Cited Smith, R. L., Demers, C. J., & Collins, S. D. (2010). Microfluidic device for the combinatorial application and maintenance of dynamically imposed diffusional gradients. Microfluidics and Nanofluidics, 9(4-5), 613–622. doi:10.1007/s10404-010-0574-7 Support Figure 1: Day 12 in differentiation media. This panel shows a phase contrast image of the culture in a 12-well plate. The center of the culture appears to undergo cell death over time. NSF Award #1145949 University of Maine RRF GSBSE Figure 4: Day 12 in differentiation media. This panel shows a phase contrast image of the culture in a 12-well plate. The region outlined in red represents approximately the location of the spontaneously beating cells.