Cross-talk between the kidney and the cardiovascular system.

In recent years, increasing evidence has been provided that even minor renal dysfunction is a powerful cardiovascular risk factor that induces typical cardiovascular alterations and thus predisposes to coronary heart disease as well as to noncoronary cardiovascular problems. This first had been noted in patients with diabetes but now has been confirmed amply in patients without diabetes as well. Numerous heterogeneous abnormalities have been described in patients with early renal dysfunction (e.g., microalbuminuria, reduced estimated GFR). One final common pathway seems to be endothelial cell dysfunction. The link between albuminuria and generalized endothelial cell dysfunction (as indicated by diminished flow-mediated vasodilation, markers of endothelial cell dysfunction, sloughed off endothelial cells, and high transcapillary albumin escape rate) is unclear. In patients with early renal dysfunction, a long list of classical and nonclassical cardiovascular risk factors have been identified: Elevated asymmetric dimethyl-l-arginine concentrations, markers of microinflammation, oxidative stress, features of metabolic syndrome, abnormal adipokine concentrations, dyslipidemia, inappropriate activation of the renin-angiotensin system, and sympathetic overactivity. The mechanisms that link dysfunction of the kidney and the cardiovascular system are being sought. The most interesting unifying concept, however, is deranged fetal programming linking nephron underdosing to the increased cardiovascular risk.