Pathogenesis of acute renal failure: new aspects.

Based on 2 case presentations - acute renal failure (ARF) due to myeloma kidney and due to angiotensin-converting enzyme inhibitor administration in the presence of transplant artery stenosis - new aspects in the pathogenesis of ARF are presented and discussed. The multifactorial pathogenesis of ARF includes (a) a disturbance of glomerular microcirculation (afferent and perhaps mesangial constriction, inadequate efferent dilatation); (b) a disturbance of medullary microcirculation (medullary capillary congestion) attributed to a combination of endothelial damage and tubular dilatation; (c) tubular cell damage which, though rarely in humans justifying the term 'acute tubular necrosis', promotes both backleak of glomerular filtrate and shedding of brush border vesicles; (d) the latter promotes tubular obstruction by casts which consist of Tamm-Horsfall protein and brush border components. Once ARF is established, repair processes set in which appear to depend on growth factors such as epidermal growth factor and insulin-like growth factor 1, of which there is a relative shortage in established ARF. Experimental therapeutic approaches focus on the restitution of microcirculation (endothelin receptor antagonists, atriopeptins), interference with cast formation (integrin receptor blockers), and the promotion of recovery by growth factors.