Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Selective cyclooxygenase (COX)-2 inhibitors that are in widespread clinical use were developed to avoid side effects of conventional NSAIDs, including gastrointestinal and renal toxicity. However, COX-2 is constitutively expressed in the kidney and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in maintenance of renal blood flow, mediation of renin release, and regulation of sodium excretion. COX-2 inhibition may transiently decrease urine sodium excretion in some subjects and induce mild to moderate elevation of blood pressure. Furthermore, in conditions of relative intravascular volume depletion and/or renal hypoperfusion, interference with COX-2 activity can have deleterious effects on maintenance of renal blood flow and glomerular filtration rate. In addition to physiological regulation of COX-2 expression in the kidney, increased renal cortical COX-2 expression is seen in experimental models associated with altered renal hemodynamics and progressive renal injury (decreased renal mass, poorly controlled diabetes), and long-term treatment with selective COX-2 inhibitors ameliorates functional and structural renal damage in these conditions.
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PMID:Cyclooxygenases, the kidney, and hypertension. 1473 22

Persistent reduction of renal perfusion pressure induces renovascular hypertension by activating the renin-angiotensin-aldosterone system; however, the sensing mechanism remains elusive. Here we investigated the role of PGI2 in renovascular hypertension in vivo, employing mice lacking the PGI2 receptor (IP-/- mice). In WT mice with a two-kidney, one-clip model of renovascular hypertension, the BP was significantly elevated. The increase in BP in IP-/- mice, however, was significantly lower than that in WT mice. Similarly, the increases in plasma renin activity, renal renin mRNA, and plasma aldosterone in response to renal artery stenosis were all significantly lower in IP-/- mice than in WT mice. All these parameters were measured in mice lacking the four PGE2 receptor subtypes individually, and we found that these mice had similar responses to WT mice. PGI2 is produced by COX-2 and a selective inhibitor of this enzyme, SC-58125, also significantly reduced the increases in plasma renin activity and renin mRNA expression in WT mice with renal artery stenosis, but these effects were absent in IP-/- mice. When the renin-angiotensin-aldosterone system was activated by salt depletion, SC-58125 blunted the response in WT mice but not in IP-/- mice. These results indicate that PGI2 derived from COX-2 plays a critical role in regulating the release of renin and consequently renovascular hypertension in vivo.
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PMID:Decreased susceptibility to renovascular hypertension in mice lacking the prostaglandin I2 receptor IP. 1537 97

Nonsteroidal antiinflammatory drugs (NSAID) are one of the most commonly used medications worldwide to inhibiting COX activity for the treatment of pain and inflammation. Their nephrotoxicity has been well documented. With the development and clinical implementation of new COX-2 inhibitors, the safety, including the effects on renal function and blood pressure, is attracting increasing attention. In the kidney, COX-2 is constitutively expressed and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in mediation of renin release, regulation of sodium excretion and maintenance of renal blood flow. Similar to conventional NSAIDs, inhibition of COX-2 may cause edema and modest elevations in blood pressure in a minority of subjects. COX-2 inhibitors may also exacerbate preexisting hypertension or interfere with other antihypertensive drugs. Occasional acute renal failure has also been reported. Caution should be taken when COX-2 inhibitors are prescribed, especially in high-risk patients (including elderly and patients with volume depletion). Recently, agents with combined lipooxygenase/COX inhibition and agents that combine NSAIDs with a nitric oxide (NO) donor have been reported to reduce adverse renal effects.
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PMID:Renal effects of non-steroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors. 1589 76

AT(1) double receptor (AT(1A) and AT(1B)) knockout mice have lower blood pressure, impaired growth, and develop early renal microvascular disease and tubulointerstitial injury. We hypothesized that there would be an increased expression of vasoactive, profibrotic, and inflammatory mediators expressed in the kidneys of AT(1) double-knockout mice. We examined the renal expression of various mediator systems in control (n = 6) vs. double-knockout mice (n = 6) at 3-5 mo of age by real-time PCR, immunohistochemistry, and Western blot analysis. AT(1) double-knockout mice show activation of Th1-dependent pathways (with increased expression of IFN-alpha, IL-2 mRNA) with increased expression of both monocyte (MCP-1 mRNA) and T cell (RANTES mRNA) chemokines, infiltration of CD4(+) and CD11b(+) cells, increased fibrosis-associated mediators (CTGF, TGF-beta and TNF-alpha mRNA) and extracellular matrix (collagens I and III mRNA and protein) deposition compared with controls (P < 0.05 for all markers). These changes were associated with increased mRNA expression of endothelin (ET)-1 and ET-A receptor (P < 0.05), cyclooxygenase (COX)-2/TXA2 synthase (P < 0.05), NADPH oxidase (p40-phox, p67-phox, P < 0.05) and iNOS and nNOS (P < 0.05). COX-2 and nNOS protein were also increased in the kidneys of AT(1) double-knockout mice by Western blot analysis (P < 0.05). Although renin and angiotensinogen mRNA expression were increased in the knockout mice, AT(2) receptor mRNA expression was not significantly different from wild-type mice. In conclusion, the absence of the AT(1) receptor is associated with marked renal alterations in vasoactive, profibrotic, and immune mediators with an inflammatory pattern favoring a Th1 phenotype.
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PMID:Th1 inflammatory response with altered expression of profibrotic and vasoactive mediators in AT1A and AT1B double-knockout mice. 1592 10

Several clinical trials have shown that agents blocking the renin-angiotensin system reduce the incidence of acute ischaemic events. This effect was independent from blood pressure reduction and was presumably related to plaque stabilisation. With the aim of investigating potential mechanisms underlying this effect, carotid plaques were analysed in a recent study from patients randomised to treatment with the angiotensin receptor blocker irbesartan, or the diuretic chlorthalidone for 4 months before carotid endarterectomy. It was found that irbesartan decreased inflammatory infiltration, increased collagen content and downregulated prostaglandin E2-dependent metalloproteases as a consequence of suppression of inducible COX-2/prostaglandin E synthase. This article reviews the results of this study and the most recent evidence that supports the possibility that angiotensin II receptor blockers represent a novel therapy for plaque stabilisation.
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PMID:Role of angiotensin II receptor blockers in atherosclerotic plaque stability. 1644 22

Macula densa (MD) cells of the juxtaglomerular apparatus (JGA) synthesize type 1 nitric oxide synthase (NOS1) and type 2 cyclooxygenase (COX-2). Both nitric oxide (NO) and prostaglandins have been considered to mediate or modulate the control of renin secretion. Reactive oxygen species (ROS) produced locally by NADPH oxidase may influence NO bioavailability. We have tested the hypothesis that in hypertension elevated ROS levels may modify the expression of NOS1 and COX-2 in the JGA, thereby interacting with juxtaglomerular signaling. To this end, spontaneously hypertensive rats (SHR) and Wistar-Kyoto control rats (WKY) received the specific NADPH oxidase inhibitor, apocynin, during 3 wk. Renal functional and histochemical parameters, plasma renin activity (PRA), and as a measure of ROS activity, urinary isoprostane excretion (IP) were evaluated. Compared with WKY, IP levels in untreated SHR were 2.2-fold increased, and NOS1 immunoreactiviy (IR) of JGA 1.5-fold increased, whereas COX-2 IR was reduced to 35%, renin IR to 51%, and PRA to 7%. Apocynin treatment reduced IP levels in SHR to 52%, NOS1 IR to 69%, and renin IR to 62% of untreated SHR, whereas renin mRNA, COX-2 IR, glomerular filtration rate, PRA, and systolic blood pressure remained unchanged. WKY revealed no changes under apocynin treatment. These data show that NADPH oxidase is an important contributor to elevated levels of ROS in hypertension. Upregulation of MD NOS1 in SHR may have the potential of blunting the functional impact of ROS at the level of bioavailable NO. Downregulated COX-2 and renin levels in SHR are apparently unrelated to oxidative stress, since apocynin treatment had no effect on these parameters.
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PMID:Effect of apocynin treatment on renal expression of COX-2, NOS1, and renin in Wistar-Kyoto and spontaneously hypertensive rats. 1646 5

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of pain and inflammation. Nonselective NSAIDs inhibit both cyclooxygenase (COX)-1 and COX-2. Nephrotoxicity of nonselective NSAIDs has been well documented. The effects of selective COX-2 inhibitors on renal function and blood pressure are attracting increasing attention. In the kidney, COX-2 is constitutively expressed and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in the mediation of renin release, regulation of sodium excretion, and maintenance of renal blood flow. Similar to nonselective NSAIDs, inhibition of COX-2 may cause edema and modest elevations in blood pressure in a minority of subjects. COX-2 inhibitors may also exacerbate preexisting hypertension or interfere with other antihypertensive drugs. Occasional acute renal failure has also been reported. Caution should be taken when COX-2 inhibitors are prescribed, especially in high-risk patients (including elderly patients and patients with volume depletion).
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PMID:COX-2 and the kidney. 1678 27

Non-steroidal anti-inflammatory drugs (NSAIDs) represent a clinically important class of agents. NSAIDs are commonly used in treatment of conditions such as headache, fever, inflammation and joint pain. Complications often arise from chronic use of NSAIDs. Gastrointestinal (GI) toxicity in the form of gastritis, peptic erosions and ulcerations and GI bleeds limit usage of NSAIDs. These toxicities are thought to be due to cyclooxygenase (COX)-1 blockade. COX-1 generates cytoprotective prostanoids such as prostaglandin (PG) E2 and prostacyclin (PGI2). COX-2 inhibitors, commonly referred to as coxibs, were developed to inhibit inflammatory prostanoids without interfering with production of COX-1 prostanoids. Concerns over cardiovascular safety, however, have evolved based on the concept of inhibition of COX-2-derived endothelial prostanoids without inhibition of platelet thromboxane A2, leading to increased cardiovascular risk. The Celecoxib Long-Term Arthritis Safety Study (CLASS) trial did not show a significant increase in cardiovascular risk for celecoxib (Celebrex), but results of the Vioxx Gastrointestinal Outcomes Research (VIGOR) study showed an increased cardiovascular risk with long-term daily usage of rofecoxib in patients with rheumatoid arthritis. The Adenomatous Poly Prevention on Vioxx (APPROVe) trial further evaluated cardiovascular effects of rofecoxib and recently led to removal of this drug from the marketplace. Coxibs affect renal function via blockade of normal COX-2 functions. COX-2 expression increases in high renin states and in response to a high-sodium diet or water deprivation. PGI2 and PGE2 are the most important renal prostanoids. PGI2 inhibition results in hyperkalemia. PGE2 inhibition results in sodium retention, which leads to hypertension, peripheral edema and potentially exacerbation of heart failure. This review article discusses beneficial and deleterious effects associated with prostanoids produced by COX-1 and COX-2 in various organs and how blockade of these products translates into clinical medicine.
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PMID:Cyclooxygenase-2 inhibitors: a painful lesson. 1678 94

Interaction between the renin-angiotensin system and cyclooxygenases in the kidney regulates renal microcirculation. Activation of the (pro)renin receptor has profibrotic effects, and now Kaneshiroet al. show that it also increases COX-2 synthesis. These results may have therapeutic implications, as blocking (pro)renin-receptor interaction would prevent the increase of angiotensin generation and prostaglandin synthesis, two phenomena underlying the pathogenesis of diabetic nephropathy.
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PMID:Increased cyclooxygenase-2, hyperfiltration, glomerulosclerosis, and diabetic nephropathy: put the blame on the (pro)renin receptor? 1680 42

In the current experiments, we determined the response of plasma renin concentration (PRC) to acute intraperitoneal administration of furosemide (40 mg/kg), hydralazine (2 mg/kg), isoproterenol (10 mg/kg), candesartan (50 microg), or quinaprilate (50 microg) in conscious wild-type (WT) and cyclooxygenase (COX)-2-/- mice on three different genetic backgrounds (mixed, C57BL/6, 129J). PRC was measured in plasma obtained by tail vein puncture. Basal PRC was significantly lower in COX-2-/- than WT mice independent of genetic background (51, 10, and 17% of WT in mixed, 129J, and C57BL/6). All five acute interventions caused significant increases of PRC in both COX-2+/+ and -/- mice, but the response was consistently less in COX-2-deficient mice (e.g., DeltaPRC in ng ANG I x ml(-1) x h(-1) caused by furosemide, isoproterenol, hydralazine, quinaprilate, or candesartan 4,699 +/- 544, 3,534 +/- 957, 2,522 +/- 369, 9,453 +/- 1,705, 66,455 +/- 21,938 in 129J WT, and 201 +/- 78, 869 +/- 275, 140 +/- 71, 902 +/- 304, 2,660 +/- 954 in 129J COX-2-/-). A low-NaCl diet and enalapril for 1 wk caused a 14-fold elevation of PRC in COX-2-/- mice and was associated with a greatly increased PRC response to acute furosemide (DeltaPRC 201 +/- 78 before and 15,984 +/- 2,397 after low Na/enalapril). As measured by radiotelemetry, blood pressure and heart rate responses to furosemide, hydralazine, isoproterenol, candesartan, or quinaprilate were not different between COX-2 genotypes. In conclusion, chronic absence of COX-2 reduces renin expression, release, and PRC and is associated with a reduced ability to alter PRC during acute stimulation regardless of the nature of the stimulus. COX-2 activity does not appear to be a mandatory and specific requirement for furosemide-stimulated renin secretion.
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PMID:Low plasma renin and reduced renin secretory responses to acute stimuli in conscious COX-2-deficient mice. 1695 40


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