Low Energy Laser Irradiation of Stem Cells for Cardiac Repair After Myocardial Infarction

Summary The aim of the present study was to evaluate the possible beneficial effects of implantation of laser-irradiated mesenchymal stem cells (MSCs) into the infarcted rat heart. MSCs were isolated from rat bone marrow and grown in culture. The cells were laser irradiated with Ga-Al-As laser (810 nm wavelength), labeled with 5-Bromo-2’deoxyuridine (BrdU), and then implanted into infarcted rat hearts. Non-irradiated cells were similarly labeled and acted as control. Hearts were excised three weeks later and cells were stained for BrdU and c-kit (Stem cell marker) immunoreactivity. Infarcted hearts that were implanted with laser-treated cells showed a significant reduction of 53% in infarct size and a 5- 6.3-fold significant increase in cell density that reacted positively to c-kit. The findings of the present study provide the first evidence that LLLT can significantly increase survival and/or proliferation of MSCs post implantation into the ischemic/infarcted heart, followed by a marked reduction of scarring, and enhanced angiogenesis.