The safety of autologous intracoronary stem cell injections in a porcine model of chronic myocardial ischemia.

Background: Intracoronary mononuclear cell therapy may produce angiogenesis in chronic myocardial ischemia. Potential complications include periprocedural infarction secondary to: reduced coronary blood flow; hyperviscosity from the cell preparation; or microvascular dysfunction. To date, no studies to evaluate these potential complications have been reported. The objective of this report was to study the safety and feasibility of intracoronary injections of autologous bone marrow mononuclear cells in a porcine chronic myocardial ischemia model.

Methods: Domestic pigs (n = 5) underwent ameroid cuff placement of the left circumflex artery. Bone marrow-derived mononuclear cells [15 x 10(6) cells] labeled with CM dioctadecyl tetramethylindocarbocyanine were given by intracoronary injection. Animals were sacrificed, and hearts and vital organs were inspected grossly and by histopathology, and bone marrow underwent immunofluorescence microscopy.

Results: Troponin I levels, gross inspection and histopathology did not reveal evidence of myocardial infarction. Labeled cells were observed in perivascular structures in myocardium at the injection site in all animals and in the spleen from one animal. Bone marrow aspirates indicated labeled cells.

Conclusions: Intracoronary injection of autologous mononuclear cells in a porcine chronic myocardial ischemia model appears safe. Intracoronary injection resulted in cell localization in the perivascular areas of myocardium supplied by the injected vessel. Cell localization was observed only in the spleen in just one animal. Labeled cells were identified in bone marrow aspirates from three animals following injection, suggesting a role for bone marrow engraftment and repopulation as a possible mechanism for progenitor cell localization in myocardium.