Acute renal failure. II. Experimental models of acute renal failure: imperfect but indispensable

Acute renal failure (ARF) due to ischemic(1) or toxic renal injury, a clini cal syndrome traditionally referred to as acute tubular necrosis (ATN), is a common disease with a high overall mortality of similar to 50%. Little pr ogress has been made since the advent of dialysis more than 30 years ago in improving this outcome. During this same period, a considerable amount of basic research has been devoted to elucidating the pathophysiology of ATN. The ultimate goal of this research is to facilitate the development of ther apeutic interventions that either prevent ARF, ameliorate the severity of t ubular injury following an acute ischemic or toxic renal insult, or acceler ate the recovery of established ATN. This research endeavor has been highly successful in elucidating many vascular and tubular abnormalities that are likely to be involved in ischemic and toxic ARF. This information has led to impressive advances in the development of a number of different pharmaco logical interventions that are highly effective in ameliorating the renal d ysfunction in animal models of ARF. Although these developments are excitin g and promising, enthusiasm of investigators involved in this endeavor has been tempered somewhat by the results of a few recent clinical studies of p atients with ATN. These trials, designed to examine the efficacy in humans of some of the interventions effective in animal models of ARF,have resulte d in little or no benefit. This is therefore an important time to reevaluat e the approaches we have taken over the past three to four decades to devel op new and effective treatments for ATN in humans. The major goals of this review are 1) to evaluate the relevance and utility of the experimental mod els currently available to study ischemic and toxic renal injury, 2) to sug gest novel experimental approaches and models that have the potential to pr ovide advantages over methods currently available, 3) to discuss ways of in tegrating results obtained from different experimental models of acute rena l injury and of evaluating the relevance of these findings to ATN in humans , and 4) to discuss the difficulties inherent in clinical studies of ATN an d to suggest how studies should be best designed to overcome these problems .