Endothelial activation and the kidney: vasomediator modulation and antioxidant strategies.

We have come to appreciate that the endothelium plays a major role in regulation of renal hemodynamics and excretory function. In the normal state, the endothelium maintains an intricate balance of interacting relaxing and contracting factors that can influence vasomotor tone and renal sodium handling, but also plays a role in the control of the coagulation system and cellular proliferation. Studies of reactive oxygen species as mediators of endothelial injury have shown that the perturbed endothelium can respond to such a threat, calling on intrinsic protective mechanisms such as induction of heme oxygenase and ferritin synthesis. In vivo studies have demonstrated that these mechanisms may confer protection in experimental models of acute renal injury. However, when endothelial injury or dysfunction does occur, adverse renal hemodynamic consequences, systemic hypertension, enhanced platelet aggregation, and mesangial cell proliferation could all contribute to progressive renal dysfunction. The role of the endothelium in modulation of normal renal function and in the pathogenesis of renal diseases will be the focus of future research efforts.