Multimodality Molecular Imaging of Stem Cell Therapy for Ischemic Cardiomyopathy

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PROJECT ABSTRACT Receiving this New and Early Investigator R01 grant will help me complete my transition into an independent physician-scientist who applies advanced imaging technology to translate novel therapy to the bedside. As a cardiovascular medicine specialist with extensive training in multi-modality imaging and stem cell biology, I am in a unique position to apply my expertise to overcome important hurdles that continue to hinder the routine clinical implementation of cardiac stem cell regenerative therapy for ischemic heart disease. End-stage heart failure from ischemic heart disease remains a devastating disease with high morbidity and mortality. It is estimated that one in nine death results from heart failure. Although cardiac stem cell therapy has emerged as a promising therapy to repair or replace the damaged myocardium, results from large, randomized clinical trials using bone marrow derived stem cells have shown that only a few patients benefit. These disappointing results have fueled criticism from nonbelievers that these cells cannot regenerate the heart. It is possible, however, that these cells never reach the injured myocardium or die before they can significantly improve heart function. Clearly, we need to incorporate advanced imaging techniques to visualize stem cell fate after transplantation to gain a better understanding of why clinical trials have shown that cardiac stem cell therapy benefits only a few patients. The long-term goal of this proposal is to apply novel techniques in genome editing and multi-modality imaging to facilitate stem cell trafficking in humans in the near future. In Aim 1 of this proposal, we will use novel site- specific genome editing techniques (e.g., CRISPR) to introduce a human reporter gene, which is potentially less immunogenic, into human induced pluripotent stem cells (hiPSCs) for cell trafficking. In Aim 2, we will transplant cardiomyocytes differentiated from iPSCs (iPSC-CMs) carrying the reporter gene with and without pre-treatment with pro-survival agents into a rat model of myocardia infarction. We will perform in vivo tracking of cell survival and correlate survival curves with functional improvement. We will use molecular imaging as well as transcriptional, proteomic, and histological assays to better understand the mechanisms contributing to acute donor death and determine if the administration of adjuvant agents can improve cell survival. In Aim 3, we will determine whether the best adjuvant therapy identified in Aim 2 will also improve cell survival in a porcine model of ischemic cardiomyopathy. We will optimize imaging and treatment protocols in this large animal model, which is necessary before initiating reporter gene imaging in humans. Information from these studies will lay the foundation for our group and others to incorporate cardiac stem cell imaging into clinical trials.