Hypertensive Cardiovascular and Renal Disease and Target Organ Damage: Lessons from Animal Models

This brief review discusses some aspects of hypertensive damage to the kidneys and cardiovascular system. A comparison of renal and cardiac manifestations of hypertensive disease between results of clinical and experimental studies was made, with a major focus on the possible role of salt and the renin-angiotensin system (RAS) in inducing target organ damage. Thus, some degree of renal impairment is often present in patients with essential hypertension, varying from microalbuminuria to end-stage renal disease, whereas in rats with spontaneous hypertension only slight renal damage is seen in old rats with little evidence of renal failure. Since renal damage in hypertensive rats is induced when they are exposed to increased salt intake, we suggested that salt may also account for kidney injury in hypertensive patients. Similarly, cardiac damage is aggravated in hypertensive human beings and rats when given salt excess. We further presented evidence that the RAS may mediate adverse cardiac and renal effects of excessive salt intake. Finally, we also discussed some aspects of the cardiovascular physiology in the giraffe, the only mammal that in comparison with the human being has extremely high pressure at the level of the heart and kidneys but no target organ damage.