The responses of cardiac cells to stress : focus on irradiation and mechanical stretch

Abstract

The heart is built for life-long uninterrupted function, supporting blood flow through the organism. During life, the organism as well as its organs will become challenged by exogenous and endogenous stresses that should be coped with. To be able to adapt to stresses such as altered loading conditions, changes in myocardial perfusion and exposure to toxic agents, the heart possesses ample capabilities. This thesis deals with the question how cardiac cells react to different stresses in an attempt to adapt to the new circumstances. The effect of mechanical stress as well as integrin stimulation on cardiac cells was examined and described. Besides we investigated the reaction of cardiac cells to DNA damage caused by either ionizing radiation or UV-irradiation. The studies reported in this thesis confirm that cardiac cells, both myocytes and fibroblasts have the capacity to respond adequately to exogenous stresses. The responses that have been studied in detail demonstrate that these cells possess systems that sense the stress, transmit its message to the cell interior, and alter gene expression, leading to appropriate reactions.