Regulation of Vascular Tone during Treatment with Cyclosporine A: Modulation of Endothelial and Vascular Smooth Muscle Function

Cyclosporine A is an efficient immunosuppressive agent, however, its use is associated with complex alterations of vascular tone. Numerous clinical and experimental observations indicate acute and chronic effects of cyclosporine A that are modulating endothelial and vascular smooth muscle function. Cyclosporine A impairs the vasodilator function of the endothelium; at the vascular smooth muscle contractions to angiotensin II are augmented, whereas conflicting results were obtained with other vasoconstrictors. Furthermore, cyclosporine A may alter circulating and locally released vasoactive hormons, such as renin/angiotensin II, catecholamines and endothelin-1. The cellular mechanisms mediating the effects of cyclosporine A in the arterial wall are not completely understood, but several experimental findings give a more and more detailed picture of potentially involved systems.