Intra- and Interorgan Communication in the Cardiovascular System: A Special View on Redox Regulation

Abstract
Intraorgan communication in the cardiovascular system is exerted not only by direct cell–cell contacts but also by locally released factors, which modulate neighboring cells by paracrine signals (e.g., NO, vascular endothelial growth factor, adenosine, reactive oxygen species). Moreover, cells in close proximity to the typical cardiovascular cells such as fibroblasts, red blood cells, as well as resident and invading immune cells must be considered in attempts to understand cardiovascular function in physiology and pathology. The second level of communication is the interorgan communication, which may be distinguished from intraorgan communication, since it involves signaling from remote organs to the heart and circulation. Therefore, mediators released by, for example, the kidney or skeletal muscle reach the heart and modulate its function. This is not only the case under physiological conditions, because there is increasing evidence that the organ-specific response to a primary insult may affect also the function of remote organs by the release of factors. This Forum will summarize novel mechanisms involved in intraorgan and interorgan communication of the cardiovascular system, with a special view on the remote organs, skeletal muscle and kidney.