Year 1

Patients with end-stage heart failure (ESHF), which can result from heart attacks, have a 2-year survival rate of 50% with conventional medical therapy. Unlike cells of other organs, the billions of cardiomyocytes lost due to damage or disease do not regenerate. Recently, implantable mechanical pumps that take over the function of the failing left ventricle (left ventricular assist devices; LVADs) have been used to prolong the lives of heart failure patients. However, these devices carry an increased risk of stroke. The only current bona fide cure for ESHF is heart transplantation, but the shortage of donor organs and the risks associated with life-long use of powerful immunosuppressive drugs limit the number of patients that can be helped.

Human embryonic stem cells (hESCs) have the unique properties of being able to grow without limit and to be converted into all the cell types of the body, including cardiomyocytes. Our project seeks to find ways to treat patients by replacing their lost cardiomyocytes with healthy ones derived from hESC. The ultimate goal of this 4 year project is to evaluate the feasibility, safety, and efficacy of this approach in both small and large animal models of heart disease and to use this data to initiate a clinical trial to test the therapy in patients.

In our first year, we developed methods for producing essentially unlimited quantities of cardiomyocytes from hESCs using a process that is compatible both with clinical needs and large-scale industrial cell production. We have also developed models of heart disease in both rats and pigs, and have begun transplanting the stem cell-derived cardiomyocytes into the rat model. We have demonstrated that stem cell-derived cardiomyocytes can engraft in this animal model and we are testing their effects on the pumping function of the heart, the growth of replacement blood vessels lost during a heart attack, and the size of the scar that typically forms after injury. In the next several years, we will continue to evaluate the safety and function of these cells and will start to transplant in our large animal model of heart disease, which will enable us to test these cells in a heart with very similar characteristics to humans, delivered in a minimally invasive way that would be ideal for clinical use.