Ren-Ke Li, PhD, MD

My research group in the Division of Cardiovascular Surgery focuses on translational research to apply new insights discovered through basic science research to clinical applications for cardiac regeneration and repair. Our research areas are:
  1. Cell transplantation into damaged myocardial tissue to regenerate myocardium and restore cardiac function
  2. Tissue engineering to create a muscle graft using autologous cells in combination with biomaterials for repair of cardiac defects
In 1996, I demonstrated that cardiac function after myocardial infarction could be restored by transplantation of healthy cells. Since then we have performed a number of studies to identify the optimal conditions to translate this technique into clinical applications. We also identified several possible mechanisms for implanted cells to regenerate injured myocardium to restore cardiac function. Early clinical data suggested that aged patients require enhanced cell therapy. Our current research therefore focuses on developing clinically relevant improvements to cell transplantation for cardiac treatment.
  • Effectiveness of cell transplantation in aged individuals
    We recently demonstrated that the ability to effectively respond to cell transplantation is impaired in aged individuals, which has led us to studies to identify possible techniques for rejuvenating recipients to enhance their responsiveness.

    We also determined that the number and quality of stem cells in aged patients was not sufficient for cardiac regeneration, which led us to find the optimal cell types for transplantation. We have explored the possibility of rejuvenating endogenous stem cells from aged patients to enhance their ability to be recruited to the injured heart and to regenerate injured tissue. In addition, we are examining methods for maximizing the effectiveness of allogeneic young cells for cell transplantation in aged hearts. As part of our search for the optimal cell type, we identified hemangioblasts in adult uterine tissue that may have potential for both transplantation and endogenous repair.
  • Therapeutic factors that improve cell transplantation
    We have identified a number of biological factors that have beneficial effects on implanted cell survival and wound healing in the damaged heart. To effectively delivery these molecules to the injured tissue, we have developed a non-invasive targeted delivery technique. Using ultrasound targeted microbubble destruction, we can repeatedly deliver regenerative molecules to an injured heart. As another technique for delivery of regenerative molecules, we synthesized a temperature sensitive hydrogel, which is liquid at room temperature and a gel at body temperature. We are currently using these two delivery systems to deliver regenerative factors into injured tissue for cardiac repair.
  • Tracking cell retention
    We have developed molecular imaging techniques to label and track transplanted cells. This non-invasive method has allowed us to determine the optimal methods of implantation to maximize cell retention.

    Some of the advances I have made in cell transplantation are currently being used to treat cardiac patients in clinical trials.
  • Tissue engineering
    A great challenge in growing cells to repair cardiac defects is encouraging them to grow as an integrated three-dimensional structure. We have developed biodegradable materials that support the growth of cells in three-dimensions and have improved heart function by using these cell-seeded materials to surgically replace damaged heart tissue. This technique is being refined to fully realize the potential of these grafts. We recently showed that the inclusion of the regenerative factors mentioned above enhanced the effectiveness of these grafts for cardiac repair.

    These projects are supported by the Canadian Institutes of Health Research and the Heart and Stroke Foundation of Ontario.
J Thorac Cardiovasc Surg. 2009 Feb;137(2):471-80
Angoulvant D, Fazel S, Weisel RD, Lai TY, Fedak PW, Chen L, Rafati S, Seneviratne CK, Degousee N, Li RK
J Thorac Cardiovasc Surg. 2008 Nov;136(5):1388-9
Fazel SS, Angoulvant D, Butany J, Weisel RD, Li RK
Am J Physiol Heart Circ Physiol. 2009 Jan;296(1):H43-50
Sun J, Li SH, Liu SM, Wu J, Weisel RD, Zhuo YF, Yau TM, Li RK, Fazel SS
Circulation. 2008 Sep 30;118(14 Suppl):S130-7
Farahmand P, Lai TY, Weisel RD, Fazel S, Yau T, Menasche P, Li RK
Eur J Heart Fail. 2008 Jun;10(6):525-33
Sun Z, Wu J, Fujii H, Wu J, Li SH, Porozov S, Belleli A, Fulga V, Porat Y, Li RK
Cell Transplant. 2008;16(10):993-1005
Wu J, Sun Z, Sun HS, Wu J, Weisel RD, Keating A, Li ZH, Feng ZP, Li RK
Circulation. 2008 Apr 1;117(13):1701-10
Degousee N, Fazel S, Angoulvant D, Stefanski E, Pawelzik SC, Korotkova M, Arab S, Liu P, Lindsay TF, Zhuo S, Butany J, Li RK, Audoly L, Schmidt R, Angioni C, Geisslinger G, Jakobsson PJ, Rubin BB
Eur J Heart Fail. 2008 Jan;10(1):14-21
Kim BO, Verma S, Weisel RD, Fazel S, Jia ZQ, Mizuno T, Li RK
Cardiovasc Pathol. 2008 Jan-Feb;17(1):32-9
Cimini M, Fazel S, Fujii H, Zhou S, Tang G, Weisel RD, Li RK
Analyst. 2008 Jan;133(1):85-92
Wang X, Ellis JS, Kan CD, Li RK, Thompson M



Professor, Department of Surgery, Division of Cardiovascular Surgery, University of Toronto