Angiogenesis and expression of tenascin after transmural laser revascularization

Abstract

Transmyocardial revascularization (TMR) with CO2-laser equipment is an alternative approach in the treatment of patients with severe ischemic cardiac disease. Several studies concerning morphological features after TMR document a strong transmyocardial injury, but little is known about wound healing in laserinduced alterations of the cardiac skeleton and their putative role for angiogenesis and endothelialization. The present study was conducted to establish a useful immunohistochemical marker for detection of these laser-induced injuries and to analyze starting points of angiogenesis in human myocardium after TMR. Our data show that tenascin labeling is a useful immunohistochemical approach to detect laser-alterated segments of the cardiac skeleton as well as laser-induced fibrosis. Starting points of the angiogenetic process are seen throughout the margins of laser-induced lesions, where myocardial capillaries are found. Disrupted vessels located within laser-alterated connective tissue septa are not major starting points for endothelialization of laser-induced lesions and for capillary sprouts. In comparison to laser-induced fibrosis, induction and promotion of angiogenesis by laser radiation is weak.