Protective importance of the myogenic response in the renal circulation.

Primary essential hypertension is second only to diabetic nephropathy as a etiology for end-stage renal disease.1 In addition, coexistent/superimposed hypertension plays a major role in the progression of most forms of chronic kidney disease (CKD), including diabetic nephropathy.2–5 Nevertheless, the individual risk is very low, with 1% of the hypertensive population developing end-stage renal disease. Such data indicate that there must be mechanisms that normally protect the kidneys from hypertensive injury of a severity sufficient to result in end-stage renal disease. The following Brief Review summarizes the evidence that indicates that the renal autoregulatory response, primarily mediated by the myogenic mechanism, is largely responsible for such protection. Moreover, the differing patterns of renal damage that are observed in clinical and experimental hypertension are best explained when considered in the context of alterations in the renal autoregulatory capacity. Recent data also indicate that hypertensive renal damage correlates most strongly with systolic blood pressure (BP).6–8 Accordingly, the review further emphasizes the kinetic characteristics of the renal myogenic response to oscillating BP signals that render it particularly capable of providing protection against systolic pressures.