Kidney and hypertension-causes. Update 2003

Renal disease is closely associated with hypertension. On the one hand, kidney disease provokes hypertension. On the other hand, hypertension aggravates the progression of renal dysfunction. The pathomechanisms through which the kidney raises blood pressure have been considerably clarified in recent years. In experimental and clinical studies, it could be shown that "hypertension goes with the kidney". This suggests that some renal anomalies predispose to hypertension. Recently, it could be shown that the kidneys of individuals with so-called essential hypertension have less glomeruli than the kidneys of control individuals. In renal patients the kidney raises blood pressure through several mechanisms. First, the pressure-natriuresis relationship is shifted to the right, i. e., sodium excretion requires higher renal perfusion pressures. Second, there is inappropriate activation of the renin-angiotensin system. Third, as only recently documented in detail, renal injury raises the sympathetic tone, even when whole kidney glomerular filtration rate (GFR) is unchanged. This results from stimulating afferent signals emanating from the kidney. Fourth, there is evidence of impaired endothelial cell dependent vasodilatation even in very early stages of renal dysfunction. Fifth, the pulse pressure profile is altered as a consequence of premature and accelerated aging causing stiffening of the aorta. Knowledge of these pathomechanisms is important for selection of appropriate antihypertensive treatment.