Heart failure following a heart attack continues to be the leading cause of death in the United States, and the rest of the western world. The limited ability of the adult human heart to regenerate after a heart attack has led to much excitement regarding the potential of human embryonic stem cells to form cardiac muscle to repair the heart as well as provide models of human heart disease in a dish. This has, however, not yet been achieved because the cardiac muscle cells that are formed from human embryonic stem cells are immature and have poor survival upon transplantation in the heart. We hypothesize that the natural framework of the heart, the extracellular matrix, plays a key role in promoting survival and maturation of these cells. We have isolated this cardiac extracellular matrix from both adult human and porcine hearts and will use this as a platform to study the matrix effects on cardiac cell survival and maturation in a dish as well as in a rodent heart attack model. If successful, our studies will significantly advance the cardiac stem cell and regenerative medicine fields by using tissue engineering approaches to create an appropriate model system to understand the basic mechanisms underlying cardiac related survival, differentiation, maturation and function, with the potential development of a minimally invasive tissue engineering stem cell-based therapy for heart attacks and heart failure.
Statement of Benefit to California:
Heart failure following a heart attack is the leading cause of death in the United States, and in California. Other than heart transplantation for end-stage heart failure, there are no effective therapies to treat myocardial infarction and heart failure. This results in a diminished quality of life and loss of life for millions of patients and an extreme burden on the U.S. health care system. With this work, we will better understand how to form mature cardiac muscle from human embryonic stem cells, which could enable the development of novel minimally invasive tissue engineering therapies for treating heart attacks and heart failure.
The inability to derive fully mature cardiomyocytes from human embryonic stem cells (hESC) in vitro has stymied efforts to use such cells for cardiac regenerative purposes. This proposal aims to investigate the hypothesis that cardiac extracellular matrix can be used to promote differentiation and maturation of hESC-derived cardiomyocytes (hESC-CM) in vitro, as well as their survival and function in vivo. The applicant will first carry out molecular, cellular and functional analyses of hESC-derived cardiomyocytes (hESC-CM) grown on human or porcine cardiac matrix in vitro. Next, the human immune response to porcine and human matrices with and without hESC-CM will be evaluated in an animal model. Finally, hESC-CMs grown on human or porcine matrix will be tested for their ability to mature, engraft, and ameliorate cardiac function in a myocardial infarction model.
Significance and Innovation
- Demonstration of significantly enhanced cell survival and retention after transplantation into the heart would be highly significant as this is a major bottleneck in the field.
- A mechanistic understanding of how myocardial matrix might improve cell survival and maturation would help validate that approach to cell therapies in the heart.
- The idea of combining cells with matrix for transplantation is logical but not novel.
Feasibility and Experimental Design
- Reviewers were not convinced that the preliminary data strongly supported the application’s core hypothesis that the proposed matrix is significantly superior to other matrices for achieving improved cardiomyocyte differentiation, survival and function.
- Reviewers were skeptical about whether the method used to prepare the matrix, involving enzymatic digestion and liquefaction, would leave protein sufficiently intact to retain all signals that might be important for cardiomyocyte differentiation and function.
- The studies proposed to identify signaling pathways activated by myocardial matrix are overly ambitious as it is likely that large numbers of potential targets will be identified and no specific method of data analysis and interpretation was described. Similarly, it was unclear how the transcriptional and proteomic data would be linked and interpreted.
Principal Investigator (PI) and Research Team
- The PI is a biomaterials scientist with a specific interest in cardiac regeneration and a solid track record.
- The team is very experienced with the required expertise to carry out the work.
- The commitment of the team is strong and the budget appears reasonable.
Responsiveness to the RFA
- The proposal is responsive to the RFA in that it studies mechanisms of differentiation of human stem cells.