School of Medicine

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  • Shin Yajima

    Shin Yajima

    Postdoctoral Scholar, Cardiothoracic Surgery

    BioI am a board-certified attending cardiothoracic surgeon in Japan. Throughout my clinical experience and research, I found that insufficient myocardial blood flow had little impact on myocardial functional recovery since percutaneous coronary intervention or coronary artery bypass grafting (CABG) could approach and supply blood flow to the superficial large coronary arteries, but not to intramyocardial microvascular arteries, particularly where microvasculature was either scarce or absent. In addition, myocardial ischemia-reperfusion (I/R) adversely affected cardiac functional recovery in ischemic hearts, including transplanted hearts. Therefore, I have a keen interest in addressing myocardial microvascular dysfunction and myocardial I/R injury in research.
    During my Ph.D. in cardiovascular surgery, I focused on a prostacyclin analog that has thromboxane A2 synthase inhibitory activity and can promote angiogenesis and restore myocardial blood flow through proangiogenic and vasodilatory effects. I applied a microform of this compound in the porcine ischemia cardiomyopathy model with a direct epicardial placement, elucidating promoted myocardial angiogenesis, leading to myocardial function recovery. Then, I developed nanoparticles (NPs) that incorporated this compound which I subsequently applied to a rat ischemia myocardial reperfusion model with intravenous injection to elucidate attenuated myocardial I/R injury with selective accumulation in the ischemic myocardium, better-preserved capillary networks, a better-preserved myocardial blood flow, and a smaller infarct size. Furthermore, I have worked on tissue engineering for myocardial regeneration using induced pluripotent stem cells (iPSCs) and adipose-derived mesenchymal stem cells. With human iPSCs-derived cardiomyocyte sheets of direct implantation on the ischemic myocardial tissue, we elucidated myocardial regeneration through thickened myocardial tissue, proangiogenic effects, improved cardiac performance, and attenuated left ventricular remodeling in both small and large animals. These works have already been published (below are representative), and I gained several academic awards and research grants (ongoing research support; Japan Heart Foundation/Bayer Research Grant Abroad, 01/01/2022 - 12/31/2022).
    My career goal is to become a leader in academic cardiovascular surgery. During my postdoctoral fellowship, I plan to develop novel therapeutic methods to obtain better outcomes for ischemic heart disease in which there is room for improvement through engineering analysis and the creation of innovative solutions. I am extremely excited to start on the proposed project, as it perfectly intertwines my bioengineering background and clinical interests. As such, the School of Medicine Dean's Postdoctoral Fellowship will be invaluable to my development as a young investigator. Dr. Woo is an exceptional mentor with remarkable renown for training academic surgeons and Stanford University provides incredible resources for research. I feel extremely fortunate to have such an ideal environment to carry out this project and continue advancing the field of cardiothoracic surgery through bioengineering.