Angiotensin II type 1 receptor blockade inhibits the development and progression of HIV-associated nephropathy in a mouse model.

Abstract

HIV-associated nephropathy (HIVAN) is characterized by a collapsed glomerular capillary tuft with hyperplasia and hypertrophy of podocytes. Recently generated were conditional transgenic mice (podocin/Vpr) that express one of the HIV-1 accessory genes, vpr, selectively in podocytes using podocin promoter and Tet-on system. These transgenic mice developed renal injury similar to HIVAN when treated with doxycycline for 8 to 12 wk. This study demonstrated that nephron reduction by heminephrectomy markedly enhanced phenotypic changes of podocytes and led to severe FSGS within 4 wk. Nephrotic-range proteinuria was observed already at 2 wk, together with dedifferentiation and dysregulation of podocytes, indicated by decreased expression of nephrin, synaptopodin, and Wilms' tumor 1 protein and increased expression of Ki-67. The acceleration of phenotypic changes of podocytes, proteinuria, and subsequent glomerulosclerosis by heminephrectomy was almost completely inhibited by angiotensin II type 1 receptor (AT1R) blocker olmesartan. In contrast, the renoprotective effect of the calcium channel antagonist azelnidipine was minimal, although it lowered systemic BP to the same level as olmesartan, demonstrating that the inhibitory effect of AT1R blocker was independent of systemic BP. Olmesartan also reduced proteinuria and prevented glomerulosclerosis even by the delayed treatment, which was initiated after the podocyte injury appeared. These data suggest that nephron reduction exaggerates podocyte injury and subsequent glomerulosclerosis, possibly through glomerular hypertension, in the mouse model of HIVAN. AT1R blockade could be beneficial in the treatment of HIVAN by ameliorating podocyte injury by avoiding the vicious cycle of nephron reduction and glomerular hypertension.

• Authors: Noriyuki Hiramatsu, Keiju Hiromura, Tetsuya Shigehara, Takashi Kuroiwa, Hiroshi Ideura, Noriyuki Sakurai, Shigeru Takeuchi, Mai Tomioka, Hidekazu Ikeuchi, Yoriaki Kaneko, Kazue Ueki, Jeffrey B Kopp, Yoshihisa Nojima
• Journal: Journal of the American Society of Nephrology : JASN (J Am Soc Nephrol) Vol. 18 Issue 2 Pg. 515-27 (Feb 2007) ISSN: 1046-6673 [Print] United States
• PMID: 17229913 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Angiotensin II Type 1 Receptor Blockers
• Imidazoles
• Intracellular Signaling Peptides and Proteins
• Membrane Proteins
• NPHS2 protein
• Receptor, Angiotensin, Type 1
• Tetrazoles
• olmesartan

Topics

• AIDS-Associated Nephropathy (pathology, prevention & control)
• Angiotensin II Type 1 Receptor Blockers (therapeutic use)
• Animals
• Black People
• Disease Models, Animal
• Humans
• Imidazoles (therapeutic use)
• Intracellular Signaling Peptides and Proteins (genetics)
• Kidney (pathology)
• Kidney Failure, Chronic (etiology)
• Membrane Proteins (genetics)
• Mice
• Mice, Transgenic
• Receptor, Angiotensin, Type 1 (drug effects, physiology)
• Tetrazoles (therapeutic use)