Cardiovascular Radiation Medicine 1:3 (1999) 265–269 1522-1865/99/$–see front matter. © 1999 Elsevier Science Inc. PII S1522-1865(99)00018-9 BIOLOGY ORIGINAL ARTICLE AUGMENTATION OF THE EXPRESSION OF PROANGIOGENIC GENES IN CARDIOMYOCYTES WITH LOW DOSE LASER IRRADIATION IN VITRO Ashwani Khanna, Ph.D., a Latha Raja Shankar, M.D., a Michael H. Keelan, M.D., a Ran Kornowski, M.D., b Martin Leon, M.D., c Jeffrey Moses, M.D., c and Nicholas Kipshidze, M.D., Ph.D. c, * a Medical College of Wisconsin, Milwaukee, Wisconsin, USA b Washington Hospital Center, Washington, DC, USA c Lenox Hill Hospital, New York, New York, USA Received and accepted 29 July 1999 Background and Objective. Several reports suggest that low power red laser light (LPRLL) is capable of affecting cellular processes in the absence of significant thermal effect. The objective of the present study was to determine the effect of LPRLL on proliferation of fetal cardiomyocytes in vitro and on the expression of proangiogenic genes, transform- ing growth factor-  (TGF-  ), and vascular endothelial growth factor (VEGF). Study Design/Materials and Methods. All cell cultures were irradiated with single-dose LPRLL using a He-Ne continuous wave laser (632 nm) with different doses. The effect of LPRLL on new DNA synthesis was studied by 3 H thymidine-incorporation assay. VEGF and TGF- expression by cardiomyocytes was studied by reverse transcription-poly- merase chain reaction (RT-PCR). Results. We observed that a dose-dependent increase in cardiomyocytes proliferation can be obtained with LPRLL and that there is a significant increase in VEGF and TGF- mRNA expression by cardiomyocytes. Conclusions. These data may have significant importance leading to the establishment of new methods for myocardial photoangiogenesis and photoregeneration as well as in vitro proliferation of cardiac myocytes. © 1999 Elsevier Science Inc. Keywords: Lasers; Coronary artery disease; Angiogenesis, Regeneration. Introduction High power laser therapy is a promising interven- tion in patients with coronary artery disease includ- ing transmyocardial laser revascularization for the treatment of end-stage coronary artery disease [1, 2], eximer laser-assisted angioplasy [3, 4], and selec- tive photodynamic removal of atherosclerotic plaques from vessel walls [5]. Also, in the past two decades low power laser therapy has been shown to promote wound healing and tissue repair [6–12]. Both experimental and clinical studies have demonstrated that low power red laser light (LPRLL) contributes to biomodula- * Correspondence to: Nicholas Kipshidze, M.D., Ph.D., Lenox Hill Hospital, Lenox Hill Heart and Vascular Institute, 130 E. 77th St., New York, NY 10021, USA.