Chronic Renal Diseases: Renoprotective Benefits of Renin–Angiotensin System Inhibition

Progression to renal parenchymal damage and end-stage renal disease, which seems to be largely independent of the initial insult, is the final common pathway for chronic, proteinuric nephropathies in animals and humans. The key event is enhanced glomerular capillary pressure; this impairs glomerular permeability to proteins and permits excessive amounts of proteins to reach the lumen of the proximal tubule. The secondary process of reabsorption of filtered proteins can contribute to renal interstitial injury by activating intracellular events, including upregulation of the genes encoding vasoactive and inflammatory mediators. Both interstitial inflammation and progression of disease can be controlled by such drugs as angiotensin-converting enzyme inhibitors, which strengthen the glomerular permeability barrier to proteins and thereby limit proteinuria and filtered protein-dependent inflammatory signals. Clinical data strongly suggest that remission can now be achieved in some patients with chronic renal disease. Because of the current lag time between starting treatment and remission, however, a substantial proportion of patients still progress to end-stage renal disease before renal function begins to stabilize. A multimodal approach that centers on reducing or removing all risk factors associated with the progression of renal disease may decrease the time to remission of the disease for most patients with proteinuric nephropathies.