Renal ischemia: A new perspective

Abstract

Because of the precarious balance between oxygen supply and demand within the outer medulla, the medullary thick ascending limb (mTAL) which normally operates on the verge of anoxia, becomes a prime target for ischemic injury during renal hypoperfusion, which, we feel, explains the remarkable vulnerability of the renal parenchyma to ischemia. Damage to mTALs might activate tubuloglomerular feedback before significant backleak or tubular obstruction occurs. A spectrum of injury ranging from mild mTAL ischemia to overt and generalized tubular necrosis fits the diversity of histology in ARF (acute renal failure) and the clinical experience that isosthenuria is the earliest and the most consistent functional impairment of renal ischemia.