Angiotensin II-dependent persistent podocyte loss from destabilized glomeruli causes progression of end stage kidney disease

Kidney Int. 2012 Jan;81(1):40-55. doi: 10.1038/ki.2011.306. Epub 2011 Sep 21.

Abstract

Podocyte depletion is a major mechanism driving glomerulosclerosis. Progression is the process by which progressive glomerulosclerosis leads to end stage kidney disease (ESKD). In order to determine mechanisms contributing to persistent podocyte loss, we used a human diphtheria toxin transgenic rat model. After initial diphtheria toxin-induced podocyte injury (over 30% loss in 4 weeks), glomeruli became destabilized, resulting in continued autonomous podocyte loss causing global podocyte depletion (ESKD) by 13 weeks. This was monitored by urine mRNA analysis and by quantitating podocytes in glomeruli. Similar patterns of podocyte depletion were found in the puromycin aminonucleoside and 5/6 nephrectomy rat models of progressive end-stage disease. Angiotensin II blockade (combined enalapril and losartan) restabilized the glomeruli, and prevented continuous podocyte loss and progression to ESKD. Discontinuing angiotensin II blockade resulted in recurrent glomerular destabilization, podocyte loss, and progression to ESKD. Reduction in blood pressure alone did not reduce proteinuria or prevent podocyte loss from destabilized glomeruli. The protective effect of angiotensin II blockade was entirely accounted for by reduced podocyte loss. Thus, an initiating event resulting in a critical degree of podocyte depletion can destabilize glomeruli and initiate a superimposed angiotensin II-dependent podocyte loss process that accelerates progression resulting in eventual global podocyte depletion and ESKD. These events can be monitored noninvasively in real-time through urine mRNA assays.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Angiotensin II / antagonists & inhibitors
  • Angiotensin II / metabolism*
  • Animals
  • Antihypertensive Agents / pharmacology
  • Disease Models, Animal
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Kidney Failure, Chronic / drug therapy
  • Kidney Failure, Chronic / genetics
  • Kidney Failure, Chronic / metabolism*
  • Kidney Failure, Chronic / pathology*
  • Kidney Glomerulus / metabolism*
  • Kidney Glomerulus / pathology*
  • Male
  • Membrane Proteins / genetics
  • Podocytes / drug effects
  • Podocytes / metabolism*
  • Podocytes / pathology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Inbred F344
  • Rats, Sprague-Dawley
  • Rats, Transgenic

Substances

  • Antihypertensive Agents
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • NPHS2 protein
  • RNA, Messenger
  • nephrin
  • Angiotensin II