Abstract 3501: Ventricular Arrhythmias After Intramyocardial Administration of Mesenchymal Bone Marrow Stem Cells in Acute Myocardial Infarction: An Animal Model
Background. Mesenchymal bone marrow derived cells (MSCs) have been shown to home to injured tissue and produce growth factors that aid angiogenesis. We aim to evaluate ventricular premature contractions (VPCs) and mechanical properties of cardiomyocytes after MSC transplantation using the micro-electrical mechanical systems (MEMS) Technology; these tiny microchips implanted in the heart may be used to monitor heart physiology.
Methods. An acute myocardial infarction was induced by ligation of anterior coronary artery in 10 New Zealand rabbits, weighting >3 kg (20 min of ischemia followed by reperfusion). MSCs were isolated, cultured and re-suspended in saline for injection. Injections were done at the peri-infarcted areas, in 5 rabbits we injected MSC whereas in 5 control rabbits we injected saline (to evaluate pro-angiogenic effect of intramyocardial injections i.m.). A MEMS was implanted at the border of ischemic zone and leads were connected with an external system that registered acceleration of the muscle area and recorded electric events. An arrhythmias recorder was located on the animal and the ECG was recorded for 7 days. Animals were sacrificed and histological and morphological analysis was performed.
Results. The hourly number of supraventricular and VPCs was calculated. The number of supraventricular events was not different in the 2 groups. Continuous ECG monitoring did not detect frequent (<1 hour) VPCs in any rabbit the day before injection, whereas the day after injection, frequent VPCs were observed in the MSC group, (18±5 hour). The number of VPCs peaked at 7 days (132±65 hour), 4 rabbits in the MSC group showed multifocal VPC between 1 and 7 days after injection. MEMS recorded different trace in rabbits after MSC transplantation as compared with controls. Kinesis of the border of ischemic zone recovery function after MSC transplantation. We reported a little recovery of function in the border of ischemic zone in 2 control rabbits suggesting a hypothetic role of i.m. injection in stimulating resident cells
Conclusions. Intramyocardial injection of MSC stimulates ventricular arrhythmias. MEMS technology could help to understand homing of stem cells in the left ventricular wall and could help to identify segmental recovery of contraction.