THE KIDNEY AND PRIMARY HYPERTENSION - CONTRIBUTIONS FROM RENAL-TRANSPLANTATION STUDIES IN ANIMALS AND HUMANS

Clinical studies: In clinical renal transplantation studies, recipient s of a renal graft from a donor with a genetic predisposition to hyper tension had higher blood pressures and required more antihypertensive treatment than recipients of a renal graft from a normotensive donor. In addition, blood pressure normalization in patients suffering from e ssential hypertension by bilateral nephrectomy and subsequent transpla ntation of a kidney from a normotensive donor has been reported. The i nterpretation of these data may be limited by the large number of diff erent factors that can contribute to post-transplantation hypertension in human renal transplant recipients. Experimental studies: In experi mental renal transplantation studies the contribution of individual fa ctors to post-transplantation hypertension can be independently assess ed. Besides immunological graft rejection and hypertension-induced dam age to the renal graft, a genetic predisposition to hypertension in th e kidney donor has been demonstrated to be associated with post-transp lantation hypertension in the recipient. Thus, normotensive recipients of a renal graft from a genetically hypertensive donor consistently d eveloped post-transplantation hypertension in four different animal mo dels of genetic hypertension. Furthermore, in genetically hypertensive rats bilateral nephrectomy together with transplantation of a kidney from a normotensive donor has been shown to be associated with a decre ase in blood pressure. Conclusions: Hypertension following renal trans plantation may be due to a variety of factors, including immunological graft rejection, hypertension-induced damage to the renal transplant and a genetic predisposition to hypertension of the kidney donor. The finding that blood pressure is transplanted with the renal graft in ge netic hypertension suggests a genetically determined alteration to the kidney as a major factor in the aetiology of primary hypertension. Th e nature of this factor is just beginning to be understood. Renal tran splantation studies in rat models of genetic hypertension, combined wi th the tools of molecular biology, may help to provide further insight s into the role of the kidney in primary hypertension.