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.
FASEB J. 2008 Mar;22(3):930-40
Fazel SS, Chen L, Angoulvant D, Li SH, Weisel RD, Keating A, Li RK
J Mol Cell Cardiol. 2007 Dec;43(6):733-43
Tian H, Cimini M, Fedak PW, Altamentova S, Fazel S, Huang ML, Weisel RD, Li RK
Circulation. 2007 Sep 11;116(11 Suppl):I77-82
Cimini M, Fazel S, Zhuo S, Xaymardan M, Fujii H, Weisel RD, Li RK
Am J Physiol Heart Circ Physiol. 2007 Dec;293(6):H3311-6
Spiegelstein D, Kim C, Zhang Y, Li G, Weisel RD, Li RK, Yau TM
J Am Coll Cardiol. 2007 Sep 11;50(11):1086-92
Kan CD, Li SH, Weisel RD, Zhang S, Li RK
J Heart Lung Transplant. 2007 Jun;26(6):630-6
Mamalias N, Li RK, Weisel RD, Dorian P, Chauhan VS, Nanthakumar K
Ann Thorac Surg. 2007 Mar;83(3):1110-9
Yau TM, Kim C, Li G, Zhang Y, Fazel S, Spiegelstein D, Weisel RD, Li RK
Ann Thorac Surg. 2007 Feb;83(2):640-6
Kim C, Li RK, Li G, Zhang Y, Weisel RD, Yau TM
J Clin Invest. 2006 Jul;116(7):1865-77
Fazel S, Cimini M, Chen L, Li S, Angoulvant D, Fedak P, Verma S, Weisel RD, Keating A, Li RK
Am J Physiol Heart Circ Physiol. 2006 Nov;291(5):H2057-66
Huang ML, Tian H, Wu J, Matsubayashi K, Weisel RD, Li RK



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