Richard Weisel

Administrative Assistant: Valerie Joseph, Princess Margaret Cancer Research Tower (PMCRT) Room 3-701, Valerie.Joseph@uhn.ca

Research Synopsis

Introduction: Research interests include cardiac regeneration after a myocardial infarction and improved methods to repair diseased hearts. 

Cardiac Regeneration: Studies performed at the Toronto General Research Institute were the first to show that the transplantation of heart cells into a myocardial scar restored ventricular function after cardiac injury in a rat model (Ann Thorac Surg. 1996; 62:654). Animal studies established the feasibility and efficacy of proposed regenerative methods which were then evaluated in clinical trials.

Based on the results of preclinical studies, we initiated a series of clinical trials of stem cells injected into the infarct region in patients undergoing cardiac surgery. We evaluated bone marrow stem cells injected into the heart of patients during the insertion of a left ventricular assist device to see if this strategy could avoid heart transplantation (JAMA 2019 March; 321:1176-1186). We also investigated the benefit of highly selected autologous bone marrow stem cells to improve ventricular function following coronary bypass surgery. The cells were isolated from a bone marrow aspirate in the Organ Regeneration Laboratory within the Operating Rooms at the Toronto General Hospital and then injected into the infarcted heart (J Thorac and Cardiovasc Surg. 2016 Aug 13;6(152):1582-1588). We demonstrated that cardiac regeneration could be enhanced by tissue engineering and new noninvasive methods of gene therapy. 

Cardiac Repair: We evaluated the benefits of repairing rather than replacing the mitral valve for patients with moderate and severe mitral regurgitation (N Engl J Med. 2016 May 19; 374:1932-41). Concomitant tricuspid valve repair improved outcomes for patients with both mitral and tricuspid valve insufficiency (N Eng J Med 2022 Jan 2; 386:327-339).

Summary: Cardiac regeneration and repair have been the focus of our research interests. We have been able to translate a number of our discoveries to clinical trials and some have become the standard of care.