Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020500 (hyperoxaluria)
 912 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hyperoxaluria leads to calcium oxalate (CaOx) crystallization and development of tubulointerstitial lesions in the kidneys. Treatment of hyperoxaluric rats with angiotensin II (Ang II) type I receptor blocker (ARB) reduces lesion formation. Because Ang II mediates osteopontin (OPN) synthesis, which is involved in both macrophage recruitment and CaOx crystallization, it was hypothesized that ARB acts via OPN. Hyperoxaluria was induced in 10-wk-old male Sprague-Dawley rats, and they were treated with ARB candesartan. At the end of 4 wk, kidneys were examined for crystal deposits, ED-1-positive cells, and expression of OPN mRNA. PCR was used to quantify OPN, renin, and angiotensin-converting enzyme (ACE) mRNA in kidneys. RIA was used to determine renal, plasma, and urinary OPN; plasma renin; Ang II and ACE; and renal Ang II. For evaluating oxidative stress, malondialdehyde was measured. Urinary calcium, oxalate, creatinine, and albumin were also determined. Despite similar urinary calcium and oxalate levels, kidneys of hyperoxaluric rats on candesartan had fewer CaOx crystals, fewer ED-1-positive cells, reduced OPN expression, and reduced malondialdehyde than hyperoxaluric rats. Urinary albumin excretion and serum creatinine levels improved significantly on candesartan treatment. mRNA for OPN, renin, and ACE were significantly elevated in hyperoxaluric rats. OPN synthesis and production increased with hyperoxaluria but to a lesser extent in candesartan-treated hyperoxaluric rats. These results show for the first time that oxalate can activate the renal renin-angiotensin system and that oxalate-induced upregulation of OPN is in part mediated via renal renin-angiotensin system.
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PMID:Effect of angiotensin II receptor blockage on osteopontin expression and calcium oxalate crystal deposition in rat kidneys. 1497 65

Osteopontin (OPN) is the major constituent of calcium-containing urinary stones and is involved in the inhibition of nucleation and aggregation of calcium oxalate (CaOx) crystals, promotion of the adherence of CaOx crystals to cultured renal epithelial cells, and regulation of inflammatory cells as chemokine. OPN has different effects (inhibitor and promoter) at each stage of stone formation in vitro and these multifunctional actions of OPN have not been fully elucidated. We developed a modified crystal method using collagen granules (CG) and immobilized OPN. OPN had strong inhibitory activity on the aggregation/growth of CaOx crystals, but the inhibitory activity decreased by use of OPN-immobilized CG. OPN is also a critical promoter of adherence for CaOx crystals to cultured renal epithelial cells in an in vitro experimental system. We examined the effect of OPN in vivo, by OPN siRNA transfection in rats. Hydrodynamic intravenous and renal subcapsular injections with lipofection were performed on days 1 and 8. The calcium concentration in the kidney was significantly lower and the frequency of CaOx crystal deposits in the tubules was lower in the OPN siRNA transfection group (drinking 1.5% ethylene glycol (EG)), than in the EG drinking group (sham operation) at day 15. We examined the effect of candesartan, an angiotensin II (Ang II) type 1 receptor blockers (ARB) in hyperoxaluric rats. ARB reduced crystal formation and calcium concentrations in the whole kidney. Hyperoxaluria leads to CaOx crystallization and the development of tubulointerstitial lesions in the kidney. AngII mediates OPN synthesis, which is involved in both macrophage recruitment and CaOx crystallization. OPN synthesis and production increased with hyperoxaluria but to a lesser extent in ARB-treated hyperoxaluric rats. These results show that oxalate can activate the renal renin-angiotensin system and that oxalate-induced upregulation of OPN is in part mediated via the renal renin-angiotensin system.
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PMID:[Multifunctional character of osteopontin and strategy for clinical applications]. 2130 62