Paracrine effects of direct intramyocardial implantation of bone marrow derived cells to enhance neovascularization in chronic ischaemic myocardium

Objective To determine the optimal bone marrow (BM) cell types, and their potential mechanisms of action for neovascularization in chronic ischaemic myocardium. Methods and results The functional effects, angiogenic potential and cytokine expression of direct intramyocardial implantation of autologous BM CD31-positive endothelial progenitor cells (EPC, n=9), BM mononuclear cells (MNCs, n=9), and saline (n=9) were compared in a swine model of chronic ischaemic myocardium. Autologous BM cells were harvested and catheter-based electromechanical mapping-guided direct intramyocardial injection was performed to target ischaemic myocardium. After 12 weeks, injection of BM-MNC resulted in significant improvements in left ventricular dP/dt (+21±8%, P=0.032), left ventricular pressure (+17±4%, P=0.048) and regional microsphere myocardial perfusion over ischaemic endocardium (+74±28%, P