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Xu C, Yang G, Fu Z, Chen Y, Xie S, Wang F, Yang T. Na +-Retaining Action of COX-2 (Cyclooxygenase-2)/EP 1 Pathway in the Collecting Duct via Activation of Intrarenal Renin-Angiotensin-Aldosterone System and Epithelial Sodium Channel. Hypertension 2022; 79:1190-1202. [PMID: 35296155 DOI: 10.1161/hypertensionaha.121.17245] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The collecting duct (CD) is a major site of both biosynthesis and action of prostaglandin E2 as highlighted by the predominant expression of COX-2 (cyclooxygenase-2) and some E-prostanoid (EP) subtypes at this nephron site. The purpose of this study was to determine the relevance and mechanism of CD COX-2/prostaglandin E2/EP1 signaling for the regulation of Na+ hemostasis during Na+ depletion. METHODS Mice with Aqp2Cre-driven deletion of COX-2 (COX-2fl/flAqp2Cre+) or the EP1 subtype (EP1fl/flAqp2Cre+) were generated and the Na+-wasting phenotype of these mice during low-salt (LS) intake was examined. EP subtypes responsible for prostaglandin E2-induced local renin response were analyzed in primary cultured mouse inner medullary CD cells. RESULTS Following 28-day LS intake, COX-2fl/flAqp2Cre+ mice exhibited a higher urinary Na+ excretion and lower cumulative Na+ balance, accompanied with suppressed intrarenal renin, AngII (angiotensin II), and aldosterone, expression of CYP11B2 (cytochrome P450 family 11 subfamily B member 2), and blunted expression of epithelial sodium channel subunits compared to floxed controls (COX-2fl/flAqp2Cre-), whereas no differences were observed for indices of systemic renin-angiotensin-aldosterone system. In cultured CD cells, exposure to prostaglandin E2 stimulated release of soluble (pro)renin receptor, prorenin/renin and aldosterone and the stimulation was more sensitive to antagonism of EP1 as compared other EP subtypes. Subsequently, EP1fl/flAqp2Cre+ mice largely recapitulated Na+-wasting phenotype seen in COX-2fl/flAqp2Cre+ mice. CONCLUSIONS The study for the first time reports that CD COX-2/EP1 pathway might play a key role in maintenance of Na+ homeostasis in the face of Na+ depletion, at least in part, through activation of intrarenal renin-angiotensin-aldosterone-system and epithelial sodium channel.
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Affiliation(s)
- Chuanming Xu
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City
| | - Guangrui Yang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City
| | - Ziwei Fu
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City
| | - Yanting Chen
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City
| | - Shiying Xie
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City
| | - Fei Wang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City
| | - Tianxin Yang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City
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Chen Y, Xu C. The interaction partners of (pro)renin receptor in the distal nephron. FASEB J 2020; 34:14136-14149. [PMID: 32975331 DOI: 10.1096/fj.202001711r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 11/11/2022]
Abstract
The (pro)renin receptor (PRR), a key regulator of intrarenal renin-angiotensin system (RAS), is predominantly presented in podocytes, proximal tubules, distal convoluted tubules, and the apical membrane of collecting duct A-type intercalated cells, and plays a crucial role in hypertension, cardiovascular disease, kidney disease, and fluid homeostasis. In addition to its well-known renin-regulatory function, increasing evidence suggests PRR can also act in a variety of intracellular signaling cascades independently of RAS in the renal medulla, including Wnt/β-catenin signaling, cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2 ) signaling, and the apelinergic system, and work as a component of the vacuolar H+ -ATPase. PRR and these pathways regulate the expression/activity of each other that controlling blood pressure and renal functions. In this review, we highlight recent findings regarding the antagonistic interaction between PRR and ELABELA/apelin, the mutually stimulatory relationship between PRR and COX-2/PGE2 or Wnt/β-catenin signaling in the renal medulla, and their involvement in the regulation of intrarenal RAS thereby control blood pressure, renal injury, and urine concentrating ability in health and patho-physiological conditions. We also highlight the latest progress in the involvement of PRR for the vacuolar H+ -ATPase activity.
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Affiliation(s)
- Yanting Chen
- Institute of Hypertension, Sun Yat-sen University School of Medicine, Guangzhou, China.,Internal Medicine, Division of Nephrology and Hypertension, University of Utah and Veterans Affairs Medical Center, Salt Lake City, UT, USA
| | - Chuanming Xu
- Internal Medicine, Division of Nephrology and Hypertension, University of Utah and Veterans Affairs Medical Center, Salt Lake City, UT, USA.,Center for Translational Medicine, Jiangxi University of Traditional Chinese Medicine, Nanchang, China
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Jiang X, Liu X, Liu X, Wu X, Jose PA, Liu M, Yang Z. Low-Dose Aspirin Treatment Attenuates Male Rat Salt-Sensitive Hypertension via Platelet Cyclooxygenase 1 and Complement Cascade Pathway. J Am Heart Assoc 2020; 9:e013470. [PMID: 31852420 PMCID: PMC6988172 DOI: 10.1161/jaha.119.013470] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/29/2019] [Indexed: 12/15/2022]
Abstract
Background The role of platelets in the development of vascular inflammation and endothelial dysfunction in the pathogenesis of hypertension is well established at this time. Aspirin is known to relieve pain, decrease fever, reduce inflammation, impair platelet aggregation, and prevent clotting, yet its effect in the context of salt-sensitive hypertension remains unclear. The present study investigated the importance of aspirin in inhibiting the abnormal activation of platelets and promoting the normal function of the vascular endothelium in a rat model of salt-sensitive hypertension. Method and Results Dahl salt-sensitive rats and salt-resistant rats were fed a normal-salt diet (4% NaCl), a high-salt diet (8% NaCl), or a high-salt diet with aspirin gavage (10 mg/kg per day) for 8 weeks. Blood pressure, platelet activation, vascular function, inflammatory response, and potential mechanism were measured. Low-dose aspirin (10 mg/kg per day) decreased the high-salt diet-induced elevation of blood pressure, platelet activation, leukocyte infiltration, and leukocyte-platelet aggregation (CD45+CD61+), as well as vascular endothelial and renal damage. These effects were related to the ability of aspirin to prevent the adhesion of leukocytes to endothelial cells via inhibition of the platelet cyclooxygenase 1 but not the cyclooxygenase 2 pathway. Aspirin also reversed the high-salt diet-induced abnormal activation of complement and coagulation cascades in platelets. Conclusions These results highlight a new property of aspirin in ameliorating vascular endothelial dysfunction induced by platelet activation, which may be beneficial in the treatment of salt-sensitive hypertension.
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Affiliation(s)
- Xiaoliang Jiang
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences CAMS&PUMC)BeijingChina
- Beijing Engineering Research Center for Experimental Animal Models of Human Critical DiseasesBeijingChina
| | - Xue Liu
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences CAMS&PUMC)BeijingChina
- Beijing Engineering Research Center for Experimental Animal Models of Human Critical DiseasesBeijingChina
| | - Xing Liu
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences CAMS&PUMC)BeijingChina
- Beijing Engineering Research Center for Experimental Animal Models of Human Critical DiseasesBeijingChina
| | - Xianxian Wu
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences CAMS&PUMC)BeijingChina
- Beijing Engineering Research Center for Experimental Animal Models of Human Critical DiseasesBeijingChina
| | - Pedro A. Jose
- Division of Kidney Diseases & HypertensionDepartment of MedicineThe George Washington University School of Medicine & Health SciencesWashingtonDC
- Department of Pharmacology and PhysiologyThe George Washington University School of Medicine & Health SciencesWashingtonDC
| | - Min Liu
- Department of HypertensionHenan Provincial People's HospitalPeople's Hospital of Zhengzhou UniversityZhengzhouChina
| | - Zhiwei Yang
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences CAMS&PUMC)BeijingChina
- Beijing Engineering Research Center for Experimental Animal Models of Human Critical DiseasesBeijingChina
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Effects of a Single Dose of Parecoxib on Inflammatory Response and Ischemic Tubular Injury Caused by Hemorrhagic Shock in Rats. PAIN RESEARCH AND TREATMENT 2018. [PMID: 29535870 PMCID: PMC5817310 DOI: 10.1155/2018/8375746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Parecoxib, a selective COX-2 inhibitor, is used to improve analgesia in postoperative procedures. Here we evaluated whether pretreatment with a single dose of parecoxib affects the function, cell injury, and inflammatory response of the kidney of rats subjected to acute hemorrhage. Inflammatory response was determined according to serum and renal tissue cytokine levels (IL-1α, IL-1β, IL-6, IL-10, and TNF-α). Forty-four adult Wistar rats anesthetized with sevoflurane were randomized into four groups: placebo/no hemorrhage (Plc/NH); parecoxib/no hemorrhage (Pcx/NH); placebo/hemorrhage (Plc/H); and parecoxib/hemorrhage (Pcx/H). Pcx groups received a single dose of intravenous parecoxib while Plc groups received a single dose of placebo (isotonic saline). Animals in hemorrhage groups underwent bleeding of 30% of blood volume. Renal function and renal histology were then evaluated. Plc/H showed the highest serum levels of cytokines, suggesting that pretreatment with parecoxib reduced the inflammatory response in rats subjected to hemorrhage. No difference in tissue cytokine levels between groups was observed. Plc/H showed higher percentage of tubular dilation and degeneration, indicating that parecoxib inhibited tubular injury resulting from renal hypoperfusion. Our findings indicate that pretreatment with a single dose of parecoxib reduced the inflammatory response and tubular renal injury without altering renal function in rats undergoing acute hemorrhage.
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COX-2-derived PGE 2 triggers hyperplastic renin expression and hyperreninemia in aldosterone synthase-deficient mice. Pflugers Arch 2018; 470:1127-1137. [PMID: 29455241 PMCID: PMC6013527 DOI: 10.1007/s00424-018-2118-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/26/2018] [Accepted: 02/01/2018] [Indexed: 11/25/2022]
Abstract
Pharmacological inhibition or genetic loss of function defects of the renin angiotensin aldosterone system (RAAS) causes compensatory renin cell hyperplasia and hyperreninemia. The triggers for the compensatory stimulation of renin synthesis and secretion in this situation may be multimodal. Since cyclooxygenase-2 (COX-2) expression in the macula densa is frequently increased in states of a defective RAAS, we have investigated a potential role of COX-2 and its derived prostaglandins for renin expression and secretion in aldosterone synthase-deficient mice (AS−/−) as a model for a genetic defect of the RAAS. In comparison with wild-type mice (WT), AS−/− mice had 9-fold and 30-fold increases of renin mRNA and of plasma renin concentrations (PRC), respectively. Renin immunoreactivity in the kidney cortex of AS−/− mice was 10-fold higher than in WT. Macula densa COX-2 expression was 5-fold increased in AS−/− kidneys relative to WT kidneys. Treatment of AS−/− mice with the COX-2 inhibitor SC-236 for 1 week lowered both renal renin mRNA and PRC by 70%. Hyperplastic renin cells in AS−/− kidneys were found to express the prostaglandin E2 receptors EP2 and EP4. Global deletion of EP2 receptors did not alter renin mRNA nor PRC values in AS−/− mice. Renin cell-specific inducible deletion of the EP4 receptor lowered renin mRNA and PRC by 25% in AS−/− mice. Renin cell-specific inducible deletion of the EP4 receptor in combination with global deletion of the EP2 receptor lowered renin mRNA and PRC by 70–75% in AS−/− mice. Lineage tracing of renin-expressing cells revealed that deletion of EP2 and EP4 leads to a preferential downregulation of perivascular renin expression. Our findings suggest that increased macula densa COX-2 activity in AS−/− mice triggers perivascular renin expression and secretion via prostaglandin E2.
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Gordish KL, Beierwaltes WH. Resveratrol induces acute endothelium-dependent renal vasodilation mediated through nitric oxide and reactive oxygen species scavenging. Am J Physiol Renal Physiol 2014; 306:F542-50. [PMID: 24431202 DOI: 10.1152/ajprenal.00437.2013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Resveratrol is suggested to have beneficial cardiovascular and renoprotective effects. Resveratrol increases endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) synthesis. We hypothesized resveratrol acts as an acute renal vasodilator, mediated through increased NO production and scavenging of reactive oxygen species (ROS). In anesthetized rats, we found 5.0 mg/kg body weight (bw) of resveratrol increased renal blood flow (RBF) by 8% [from 6.98 ± 0.42 to 7.54 ± 0.17 ml·min(-1)·gram of kidney weight(-1) (gkw); n = 8; P < 0.002] and decreased renal vascular resistance (RVR) by 18% from 15.00 ± 1.65 to 12.32 ± 1.20 arbitrary resistance units (ARU; P < 0.002). To test the participation of NO, we administered 5.0 mg/kg bw resveratrol before and after 10 mg/kg bw of the NOS inhibitor N-nitro-l-arginine methyl ester (l-NAME). l-NAME reduced the increase in RBF to resveratrol by 54% (from 0.59 ± 0.05 to 0.27 ± 0.06 ml·min(-1)·gkw(-1); n = 10; P < 0.001). To test the participation of ROS, we gave 5.0 mg/kg bw resveratrol before and after 1 mg/kg bw tempol, a superoxide dismutase mimetic. Resveratrol increased RBF 7.6% (from 5.91 ± 0.32 to 6.36 ± 0.12 ml·min(-1)·gkw(-1); n = 7; P < 0.001) and decreased RVR 19% (from 18.83 ± 1.37 to 15.27 ± 1.37 ARU). Tempol blocked resveratrol-induced increase in RBF (from 0.45 ± 0.12 to 0.10 ± 0.05 ml·min(-1)·gkw(-1); n = 7; P < 0.03) and the decrease in RVR posttempol was 44% of the control response (3.56 ± 0.34 vs. 1.57 ± 0.21 ARU; n = 7; P < 0.006). We also tested the role of endothelium-derived prostanoids. Two days of 10 mg/kg bw indomethacin pretreatment did not alter basal blood pressure or RBF. Resveratrol-induced vasodilation remained unaffected. We conclude intravenous resveratrol acts as an acute renal vasodilator, partially mediated by increased NO production/NO bioavailability and superoxide scavenging but not by inducing vasodilatory cyclooxygenase products.
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Affiliation(s)
- Kevin L Gordish
- Dept. Internal Medicine, Hypertension and Vascular Research Div., Henry Ford Hospital, 7088 E&R Bldg., 2799 W. Grand Blvd., Detroit, MI 48202.
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Leukotrienes, but not angiotensin II, are involved in the renal effects elicited by the prolonged cyclooxygenase-2 inhibition when sodium intake is low. J Cardiovasc Pharmacol 2013; 61:329-36. [PMID: 23288201 DOI: 10.1097/fjc.0b013e31828399ae] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It is known that cyclooxygenase-2 (COX-2) inhibition elicits significant renal hemodynamics alterations when sodium intake is low. However, the mechanisms involved in these renal changes are not well known. Our objective was to evaluate the role of angiotensin II and 5-lipooxygenase-derived metabolites in the renal effects induced by prolonged COX-2 inhibition when sodium intake is low. Conscious dogs were treated during 7 days with a COX-2 inhibitor (1 mg·kg·d, SC75416), and either a vehicle, an AT1 receptor antagonist (0.4 mg · kg · d, candesartan) or a selective 5-lipooxygenase inhibitor (PF-150, 20 and 60 mg · kg · d). The administration of SC75416 alone induced significant changes in renal blood flow (219 ± 14 to 160 ± 10 mL/min), glomerular filtration rate (51 ± 2 to 42 ± 3 mL/min), and plasma potassium (pK) (4.3 ± 0.1 to 4.6 ± 0.1 mEq/L). Similar decrements in renal blood flow (27%) and glomerular filtration rate (20%) and a similar increment in pK (7%) were found when SC75416 was administered in candesartan-pretreated dogs. However, SC75416 administration did not elicit significant changes in renal hemodynamics and pK in dogs pretreated with each dose of PF-150. Our data suggest that leukotrienes but not angiotensin II are involved in the renal effects induced by COX-2 inhibition when sodium intake is low.
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Atchison DK, Harding P, Beierwaltes WH. Vitamin D increases plasma renin activity independently of plasma Ca2+ via hypovolemia and β-adrenergic activity. Am J Physiol Renal Physiol 2013; 305:F1109-17. [PMID: 23926179 DOI: 10.1152/ajprenal.00010.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1, 25-Dihydroxycholechalciferol (calcitriol) and 19-nor-1, 25-dihydroxyvitamin D2 (paricalcitol) are vitamin D receptor (VDR) agonists. Previous data suggest VDR agonists may actually increase renin-angiotensin activity, and this has always been assumed to be mediated by hypercalcemia. We hypothesized that calcitriol and paricalcitol would increase plasma renin activity (PRA) independently of plasma Ca(2+) via hypercalciuria-mediated polyuria, hypovolemia, and subsequent increased β-adrenergic sympathetic activity. We found that both calcitriol and paricalcitol increased PRA threefold (P < 0.01). Calcitriol caused hypercalcemia, but paricalcitol did not. Both calcitriol and paricalcitol caused hypercalciuria (9- and 7-fold vs. control, P < 0.01) and polyuria (increasing 2.6- and 2.2-fold vs. control, P < 0.01). Paricalcitol increased renal calcium-sensing receptor (CaSR) expression, suggesting a potential cause of paricalcitol-mediated hypercalciuria and polyuria. Volume replacement completely normalized calcitriol-stimulated PRA and lowered plasma epinephrine by 43% (P < 0.05). β-Adrenergic blockade also normalized calcitriol-stimulated PRA. Cyclooxygenase-2 inhibition had no effect on calcitriol-stimulated PRA. Our data demonstrate that vitamin D increases PRA independently of plasma Ca(2+) via hypercalciuria, polyuria, hypovolemia, and increased β-adrenergic activity.
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Affiliation(s)
- Douglas K Atchison
- Dept. of Internal Medicine, Hypertension and Vascular Research Div., Henry Ford Hospital, 7121 E&R Bldg., 2799 W. Grand Blvd., Detroit, MI 48202.
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Pöschke A, Kern N, Maruyama T, Pavenstädt H, Narumiya S, Jensen BL, Nüsing RM. The PGE(2)-EP4 receptor is necessary for stimulation of the renin-angiotensin-aldosterone system in response to low dietary salt intake in vivo. Am J Physiol Renal Physiol 2012; 303:F1435-42. [PMID: 22993066 DOI: 10.1152/ajprenal.00512.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Increased cyclooxygenase-2 (COX-2) expression and PGE(2) synthesis have been shown to be prerequisites for renal renin release after Na(+) deprivation. To answer the question of whether EP4 receptor type of PGE(2) mediates renin regulation under a low-salt diet, we examined renin regulation in EP4(+/+), EP4(-/-), and in wild-type mice treated with EP4 receptor antagonist. After 2 wk of a low-salt diet (0.02% wt/wt NaCl), EP4(+/+) mice showed diminished Na(+) excretion, unchanged K(+) excretion, and reduced Ca(2+) excretion. Diuresis and plasma electrolytes remained unchanged. EP4(-/-) exhibited a similar attenuation of Na(+) excretion; however, diuresis and K(+) excretion were enhanced, and plasma Na(+) concentration was higher, whereas plasma K(+) concentration was lower compared with control diet. There were no significant differences between EP4(+/+) and EP4(-/-) mice in blood pressure, creatinine clearance, and plasma antidiuretic hormone (ADH) concentration. Following salt restriction, plasma renin and aldosterone concentrations and kidney renin mRNA level rose significantly in EP4(+/+) but not in EP4(-/-) and in wild-type mice treated with EP4 antagonist ONO-AE3-208. In the latter two groups, the low-salt diet caused a significantly greater rise in PGE(2) excretion. Furthermore, mRNA expression for COX-2 and PGE(2) synthetic activity was significantly greater in EP4(-/-) than in EP4(+/+) mice. We conclude that low dietary salt intake induces expression of COX-2 followed by enhanced renal PGE(2) synthesis, which stimulates the renin-angiotensin-aldosterone system by activation of EP4 receptor. Most likely, defects at the step of EP4 receptor block negative feedback mechanisms on the renal COX system, leading to persistently high PGE(2) levels, diuresis, and K(+) loss.
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Affiliation(s)
- Antje Pöschke
- Institute of Clinical Pharmacology, Goethe Univ., Frankfurt am Main, Germany
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Atchison DK, Westrick E, Szandzik DL, Gordish KL, Beierwaltes WH. Parathyroid hormone-related protein stimulates plasma renin activity via its anorexic effects on sodium chloride intake. Am J Physiol Endocrinol Metab 2012; 303:E457-63. [PMID: 22649069 PMCID: PMC3423101 DOI: 10.1152/ajpendo.00020.2012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Parathyroid hormone-related protein (PTHrP) increases renin release from isolated perfused kidneys and may act as an autacoid regulator of renin secretion, but its effects on renin in vivo are unknown. In vivo, PTHrP causes hypercalcemia and anorexia, which may affect renin. We hypothesized that chronically elevated PTHrP would increase plasma renin activity (PRA) indirectly via its anorexic effects, reducing sodium chloride (NaCl) intake and causing NaCl restriction. We infused male Sprague-Dawley rats with the vehicle (control) or 125 μg PTHrP/day (PTHrP) via subcutaneous osmotic minipumps for 5 days. To replenish NaCl consumption, a third group of PTHrP-infused rats received 0.3% NaCl (PTHrP + NaCl) in their drinking water. PTHrP increased PRA from a median control value of 3.68 to 18.4 ng Ang I·ml(-1)·h(-1) (P < 0.05), whereas the median PTHrP + NaCl PRA value was normal (7.82 ng Ang I·ml(-1)·h(-1), P < 0.05 vs. PTHrP). Plasma Ca(2+) (median control: 10.2 mg/dl; PTHrP: 13.7 mg/dl; PTHrP + NaCl: 14.1 mg/dl; P < 0.05) and PTHrP (median control: 0.03 ng/ml; PTHrP: 0.12 ng/ml; PTHrP + NaCl: 0.15 ng/ml; P < 0.05) were elevated in PTHrP- and PTHrP + NaCl-treated rats. Body weights and caloric consumption were lower in PTHrP- and PTHrP + NaCl-treated rats. NaCl consumption was lower in PTHrP-treated rats (mean Na(+): 28.5 ± 4.1 mg/day; mean Cl(-): 47.8 mg/day) compared with controls (Na(+): 67.3 ± 2.7 mg/day; Cl(-): 112.8 ± 4.6 mg/day; P < 0.05). NaCl consumption was comparable with control in the PTHrP + NaCl group; 0.3% NaCl in the drinking water had no effect on PRA in normal rats. Thus, our data support the hypothesis that PTHrP increases PRA via its anorexic effects, reducing NaCl intake and causing NaCl restriction.
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Affiliation(s)
- Douglas K Atchison
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202, USA
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Cyclooxygenase-2 and kidney failure. Prostaglandins Other Lipid Mediat 2011; 98:86-90. [PMID: 22119250 DOI: 10.1016/j.prostaglandins.2011.11.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 11/09/2011] [Accepted: 11/10/2011] [Indexed: 01/11/2023]
Abstract
Cyclooxygenase (COX)-dependent prostaglandins are necessary for normal kidney function. These prostaglandins are associated with inflammation, maintenance of sodium and water homeostasis, control of renin release, renal vasodilation, vasoconstriction attenuation, and prenatal renal development. COX-2 expression is regulated by the renin-angiotensin system, glucocorticoids or mineralcorticoids, and aldosterone, supporting a role for COX-2 in kidney function. Indeed, COX-2 mRNA and protein levels as well as enzyme activity are increased, along with PGE2, during kidney failure. In addition, changes in COX-2 expression are associated with increased blood pressure, urinary volume, sodium and protein and decreased urinary osmolarity. Intrarenal mechanisms such as angiotensin II (Ang II) production, increased sodium delivery, glomerular hypertension, and renal tubular inflammation have been suggested to be responsible for the increase in COX-2 expression. Although, specific COX-2 pharmacological inhibition has been related to the prevention of kidney damage, clinical studies have reported that COX-2 inhibition may cause side effects such as edema or a modest elevation in blood pressure and could possibly interfere with antihypertensive drugs and increase the risk of cardiovascular complications. Thus, administration of COX-2 inhibitors requires caution, especially in the presence of underlying cardiovascular disease.
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Neubauer B, Machura K, Schnermann J, Wagner C. Renin expression in large renal vessels during fetal development depends on functional beta1/beta2-adrenergic receptors. Am J Physiol Renal Physiol 2011; 301:F71-7. [PMID: 21389089 DOI: 10.1152/ajprenal.00443.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
During nephrogenesis, renin expression shifts from large renal arteries toward smaller vessels in a defined spatiotemporal pattern, finally becoming restricted to the juxtaglomerular position. Chronic stimulation in adult kidneys leads to a recruitment of renin expression in the upstream vasculature. The mechanisms that control this characteristic switch-on and switch-off in the immature and adult kidney are not well-understood. Previous studies in mice with juxtaglomerular cell-specific deletion of the adenylyl cyclase-stimulatory G protein Gsα suggested that signaling along the cAMP pathway plays an essential role for renin expression during nephrogenesis and in the adult kidney. To identify the Gsα-dependent receptor that might be involved in activating this pathway, the present studies were performed to compare renin expression in wild types with that in mice with targeted deletions of β(1) and β(2)-adrenoceptors. The sympathetic nervous system is an important regulator of the renin system in the adult kidney so that activation of β-adrenenoceptors may also participate in the activation of renin expression along the developing arterial tree and in upstream vasculature in adulthood. Compared with wild-types, renin expression was found to be significantly lower at all developmental stages in the kidneys of β(1)/β(2) Adr(-/-) mice. Three-dimensional analysis showed reduced renin expression in all segments of the vascular tree in mutants and a virtual absence of renin expression in the large arcuate arteries. Adult mutant kidneys showed the typical upstream renin expression after chronic stimulation. Tyrosine hydroxylase staining in fetal and postnatal kidneys revealed that sympathetic innervation of renin-producing cells occurs early in fetal development. Our data indicate that genetic disruption of β-adrenergic receptors reduces basal renin expression along the developing preglomerular tree and in adult kidneys. Furthermore, β-adrenergic receptor input is critical for the expression of renin in large renal vessels during early fetal development.
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Affiliation(s)
- Björn Neubauer
- Physiologisches Institut, Universität Regensburg, D-93040 Regensburg, Germany
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Silva LA, Veira-Filho LD, Barreto IS, Cabral EV, Vieyra A, Paixão AD. Prenatal Undernutrition Changes Renovascular Responses of Nimesulide in Rat Kidneys. Basic Clin Pharmacol Toxicol 2010; 108:115-21. [DOI: 10.1111/j.1742-7843.2010.00625.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Peti-Peterdi J, Harris RC. Macula densa sensing and signaling mechanisms of renin release. J Am Soc Nephrol 2010; 21:1093-6. [PMID: 20360309 DOI: 10.1681/asn.2009070759] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that generate paracrine chemical signals in the juxtaglomerular apparatus to control vital kidney functions, including renal blood flow, glomerular filtration, and renin release. Renin is the rate-limiting step in the activation of the renin-angiotensin system, a key modulator of body fluid homeostasis. Here, we discuss recent advances in understanding macula densa sensing and suggest these cells, in addition to salt, also sense various chemical and metabolic signals in the tubular environment that directly trigger renin release.
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Affiliation(s)
- János Peti-Peterdi
- Departments of Physiology and Biophysics and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA.
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Castrop H, Höcherl K, Kurtz A, Schweda F, Todorov V, Wagner C. Physiology of Kidney Renin. Physiol Rev 2010; 90:607-73. [PMID: 20393195 DOI: 10.1152/physrev.00011.2009] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The protease renin is the key enzyme of the renin-angiotensin-aldosterone cascade, which is relevant under both physiological and pathophysiological settings. The kidney is the only organ capable of releasing enzymatically active renin. Although the characteristic juxtaglomerular position is the best known site of renin generation, renin-producing cells in the kidney can vary in number and localization. (Pro)renin gene transcription in these cells is controlled by a number of transcription factors, among which CREB is the best characterized. Pro-renin is stored in vesicles, activated to renin, and then released upon demand. The release of renin is under the control of the cAMP (stimulatory) and Ca2+(inhibitory) signaling pathways. Meanwhile, a great number of intrarenally generated or systemically acting factors have been identified that control the renin secretion directly at the level of renin-producing cells, by activating either of the signaling pathways mentioned above. The broad spectrum of biological actions of (pro)renin is mediated by receptors for (pro)renin, angiotensin II and angiotensin-( 1 – 7 ).
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Klaus Höcherl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Vladimir Todorov
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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Zhang Y, Wu J, Wang X, Morgan T. Effects of enalapril and sodium depletion on the renin-angiotensin system in hydronephrotic mice. Can J Physiol Pharmacol 2009; 87:515-21. [DOI: 10.1139/y09-037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of enalapril and sodium depletion on renin synthesis and secretion were studied in mice with a left hydronephrotic kidney caused by unilateral ureteral ligation (UUL). In the control animals, there was no difference in plasma renin concentration between the right and left renal veins. In mice with left ureteral ligation, the renin concentration in the vein draining the hydronephrotic kidney was similar to or lower than that in the aorta under control conditions and after either stimulation with enalapril or depletion of sodium. Enalapril and sodium restriction increased plasma renin concentration, and this increase was due to secretion from the nonhydronephrotic kidney. The renin concentration per gram of kidney tissue and the mRNA for renin per gram of kidney tissue were similar in both the control and hydronephrotic kidney, and the values rose 3–4-fold in both kidneys after enalapril or sodium depletion. Immunostaining for renin confirmed these findings and indicated that renin per glomerulus was higher in the hydronephrotic kidney. Thus, removal or reduction of angiotensin II activity or depletion of sodium stimulated synthetic activity to a similar extent in the normal and hydronephrotic kidneys; however, secretion from the kidney without a macula densa (hydronephrotic) was not increased. Thus, the signals that control synthesis and secretion are different, and for these stimuli, secretion appears to require an intact macula densa.
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Affiliation(s)
- Yanling Zhang
- Department of Physiology, Taishan Medical University, Tai’an 271000, China
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Junyan Wu
- Department of Physiology, Taishan Medical University, Tai’an 271000, China
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Xuechun Wang
- Department of Physiology, Taishan Medical University, Tai’an 271000, China
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Trefor Morgan
- Department of Physiology, Taishan Medical University, Tai’an 271000, China
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
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Neubauer B, Machura K, Chen M, Weinstein LS, Oppermann M, Sequeira-Lopez ML, Gomez RA, Schnermann J, Castrop H, Kurtz A, Wagner C. Development of vascular renin expression in the kidney critically depends on the cyclic AMP pathway. Am J Physiol Renal Physiol 2009; 296:F1006-12. [PMID: 19261741 DOI: 10.1152/ajprenal.90448.2008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During metanephric kidney development, renin expression in the renal vasculature begins in larger vessels, shifting to smaller vessels and finally remaining restricted to the terminal portions of afferent arterioles at the entrance into the glomerular capillary network. The mechanisms determining the successive expression of renin along the vascular axis of the kidney are not well understood. Since the cAMP signaling cascade plays a central role in the regulation of both renin secretion and synthesis in the adult kidney, it seemed feasible that this pathway might also be critical for renin expression during kidney development. In the present study we determined the spatiotemporal development of renin expression and the development of the preglomerular arterial tree in mouse kidneys with renin cell-specific deletion of G(s)alpha, a core element for receptor activation of adenylyl cyclases. We found that in the absence of the G(s)alpha protein, renin expression was largely absent in the kidneys at any developmental stage, accompanied by alterations in the development of the preglomerular arterial tree. These data indicate that the maintenance of renin expression following a specific spatiotemporal pattern along the preglomerular vasculature critically depends on the availability of G(s)alpha. We infer from our data that the cAMP signaling pathway is not only critical for the regulation of renin synthesis and secretion in the mature kidney but that it also is critical for establishing the juxtaglomerular expression site of renin during development.
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Affiliation(s)
- Björn Neubauer
- Department of Physiology, Universität Regensburg, Regensburg, Germany
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Abdelrahman AM, Al Suleimani YM. Four-week administration of nimesulide, a cyclooxygenase-2 inhibitor, improves endothelial dysfunction in the hindlimb vasculature of streptozotocin-induced diabetic rats. Arch Pharm Res 2008; 31:1584-9. [DOI: 10.1007/s12272-001-2155-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 11/18/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
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Abstract
Nonsteroidal anti-inflammatory drugs represent the most commonly used medications for the treatment of pain and inflammation, but numerous well-described side effects can limit their use. Cyclooxygenase-2 (COX-2) inhibitors were initially touted as a therapeutic strategy to avoid not only the gastrointestinal but also the renal and cardiovascular side effects of nonspecific nonsteroidal anti-inflammatory drugs. However, 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. This review summarizes the current state of knowledge about both renal and cardiovascular side effects that are attributed to COX-2 selective inhibitors.
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Affiliation(s)
- Raymond C Harris
- Division of Nephrology, S3322 MCN, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Beierwaltes WH. cGMP stimulates renin secretion in vivo by inhibiting phosphodiesterase-3. Am J Physiol Renal Physiol 2006; 290:F1376-81. [PMID: 16449359 DOI: 10.1152/ajprenal.00209.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The interaction between renin, nitric oxide (NO), and its second messenger cGMP is controversial. cAMP is the stimulatory second messenger for renin but is degraded by phosphodiesterases (PDEs). We previously reported that increasing endogenous cGMP in rats by inhibiting its breakdown by PDE-5 stimulated renin secretion rate (RSR). This could be reversed by selective inhibition of neuronal nitric oxide synthase (nNOS). PDE-3 metabolizes cAMP, but this can be inhibited by cGMP, suggesting that renal cGMP could stimulate RSR by diminishing PDE-3 degradation of cAMP. Rats were anesthetized with Inactin before determination of blood pressure (BP), renal blood flow (RBF), and sampling of renal venous and arterial blood to determine RSR. In 13 rats, basal BP was 104 +/- 2 mmHg, RBF was 6.1 ml x min(-1) x g kidney wt(-1) and RSR was 2.9 +/- 1.4 ng ANG I x h(-1) x min(-1). Inhibiting PDE-5 with 20 mg/kg body wt i.p. Zaprinast did not change hemodynamic parameters but increased RSR fivefold to 12.2 +/- 4.9 ng ANG I x h(-1) x min(-1) (P < 0.05). Renal venous cAMP was increased by Zaprinast from 93.8 +/- 27.9 to 149.2 +/- 36.0 pM x min(-1) x g kidney wt(-1) (P < 0.05). When another 10 rats were treated with the PDE-3 inhibitor Milrinone (0.4 microg/min over 30 min, which did not affect hemodynamics), RSR was elevated to 10.4 +/- 4.4 ng ANG I x h(-1) x min(-1). Milrinone also increased renal venous cAMP from 212 +/- 29 to 304 +/- 29 pM x min(-1) x g kidney wt(-1) (P < 0.025). Administration of Zaprinast to rats pretreated with Milrinone (n = 10) did not further increase in RSR (7.5 +/- 3.3 ng ANG I x h(-1) x min(-1)). These results are consistent with endogenous renal cGMP inhibiting PDE-3, which diminishes renal metabolism of cAMP. The resulting increase in cAMP serves as an endogenous stimulus for renin secretion. This suggests a pathway by which NO can indirectly stimulate RSR through its second messenger cGMP.
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Affiliation(s)
- William H Beierwaltes
- Hypertension and Vascular Research Division, 7121 E&R Bldg., Henry Ford Hospital, Wayne State University, 2799 West Grand Blvd., Detroit, MI 48202, USA.
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Bergh MS, Budsberg SC. The Coxib NSAIDs: Potential Clinical and Pharmacologic Importance in Veterinary Medicine. J Vet Intern Med 2005. [DOI: 10.1111/j.1939-1676.2005.tb02741.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Dey A, Maric C, Kaesemeyer WH, Zaharis CZ, Stewart J, Pollock JS, Imig JD. Rofecoxib decreases renal injury in obese Zucker rats. Clin Sci (Lond) 2004; 107:561-70. [PMID: 15307815 DOI: 10.1042/cs20040125] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The present study tested the hypothesis that altered vascular regulation of arachidonic acid enzymes in obese Zucker rats contributes to renal damage. Protein expression of CYP450 (cytochrome P450) and COX (cyclo-oxygenase) enzymes in renal microvessels was studied in obese and lean Zucker rats at 20–21 weeks of age. Body weight and blood glucose averaged 649±13 g and 142±10 mg/dl in obese Zucker rats compared with 437±10 g and 111±5 mg/dl in age-matched lean Zucker rats. Renal microvascular CYP4A and COX-2 protein levels were increased and CYP2C protein levels decreased in obese Zucker rats. TX (thromboxane) B2 excretion was 2-fold higher and PG (prostaglandin) E2 excretion significantly lower in obese Zucker rats. Additional studies investigated the ability of the COX-2 inhibitor, rofecoxib, to slow the progression of renal injury in obese Zucker rats. Rofecoxib treatment decreased urinary PGF2α and 8-isoprostane levels in obese Zucker rats. Renal microvessel mRNA expression of pro-inflammatory chemokines was decreased in COX-2-inhibitor-treated obese Zucker rats. Urinary albumin excretion, an index of kidney damage, averaged 95±11 mg/day in vehicle-treated and 9±1 mg/day in rofecoxib-treated obese Zucker rats. Glomerulosclerosis, characterized by mesangial expansion, tubulo-interstitial fibrosis and extracellular matrix accumulation, was prominent in obese Zucker rats compared with a lack of damage in age-matched lean Zucker rats and rofecoxib-treated obese Zucker rats. These results suggest that altered vascular arachidonic acid enzymes contribute to the renal damage, and that COX-2 inhibition decreases glomerular injury in obese Zucker rats.
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Affiliation(s)
- Aparajita Dey
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA.
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Vanecková I, Cahová M, Kramer HJ, Husková Z, Skaroupková P, Komers R, Bader M, Ganten D, Cervenka L. Acute Effects of Cyclooxygenase-2 Inhibition on Renal Function in Heterozygous Ren-2-Transgenic Rats on Normal or Low Sodium Intake. Kidney Blood Press Res 2004; 27:203-10. [PMID: 15273422 DOI: 10.1159/000079865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2004] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Since there are no data available so far on the role of renal cyclooxygenase-2 (COX-2) in hypertensive Ren-2-transgenic rats (TGR), in the present study we evaluated renal cortical COX-2 protein expression and prostaglandin E2 (PGE2) concentrations as well as renal functional responses to acute COX-2 inhibition in male heterozygous TGR and in normotensive Hannover Sprague-Dawley (HanSD) rats fed either a normal-sodium (NS) or a low-sodium (LS) diet. METHODS In rats fed either the NS or the LS diet for 12 days and prepared for clearance experiments with left ureteral catheterization, the renal functional responses of the left kidney were evaluated after intrarenal COX-2 inhibition with DuP-697 or NS-398. In renal cortical tissue, COX-2 protein expression was assessed by immunoblotting, and the concentration of PGE2 as a marker of COX-2 activity was determined by enzyme immunoassay. Mean arterial pressure in the right femoral artery was monitored by means of a pressure transducer. RESULTS In heterozygous TGR, to our surprise, the LS diet normalized the mean arterial pressure. Despite significantly higher renocortical expression of COX-2 and PGE2 concentrations as well as urinary PGE2 excretion in TGR as compared with HanSD rats kept on the NS diet, selective intrarenal COX-2 inhibition did not influence renal function either in TGR or in HanSD rats. The LS diet increased renocortical COX-2 expression and PGE2 concentrations as well as urinary PGE2 excretion significantly stronger in TGR than in HanSD rats. Regardless of these increases, the intrarenal COX-2 inhibition caused comparable decreases in glomerular filtration rate, in absolute and fractional sodium excretion, as well as in urinary PGE2 excretion in TGR and HanSD rats kept on the LS diet. CONCLUSIONS The present data show that a LS diet normalizes the mean arterial pressure in heterozygous male TGR. This first study on the role of renal COX-2 in TGR also demonstrates that COX-2-derived vasodilatory prostanoids do not act as renal compensatory vasodilator and natriuretic substances in this model of hypertension.
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Affiliation(s)
- Ivana Vanecková
- Center of Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Zewde T, Mattson DL. Inhibition of cyclooxygenase-2 in the rat renal medulla leads to sodium-sensitive hypertension. Hypertension 2004; 44:424-8. [PMID: 15314032 DOI: 10.1161/01.hyp.0000140924.91479.03] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cyclooxygenase-2 expression in the renal medulla is regulated by dietary salt intake. The present study was performed to determine the influence of chronic inhibition of medullary cyclooxygenase-2 on arterial blood pressure in conscious Sprague-Dawley rats maintained on a high-salt (4% NaCl) or a low-salt (0.4% NaCl) diet. Rats were uninephrectomized and instrumented with femoral arterial and femoral vein or renal medullary interstitial catheters. Each rat received a continuous medullary or intravenous infusion of saline (0.5 mL per hour) for 3 control days, followed by infusion of the cyclooxygenase-2 inhibitor NS-398 (10 mg/kg per day) for 5 days. Medullary interstitial infusion of NS-398 significantly increased mean arterial pressure in the 4% NaCl group from 126+/-2 to 146+/-2 mm Hg (n=6) but did not alter blood pressure in the 0.4% NaCl group (n=6). Intravenous infusion of NS-398 to rats on the 4.0% NaCl diet also failed to alter mean arterial pressure (n=5). To test the blood pressure effect of a mechanistically different inhibitor of cyclooxygenase-2, an antisense oligonucleotide against cyclooxygenase-2 (18-mer; 8 nmol per hour) was infused into the renal medulla of rats maintained on a high-salt diet. Administration of the antisense oligonucleotide reduced cyclooxygenase-2 immunoreactive protein by 36% and significantly increased mean arterial pressure from 127+/-2 to 147+/-2 mm Hg (n=6). Renal medullary interstitial infusion of a scrambled oligonucleotide did not alter arterial pressure (n=5). These results demonstrate the importance of cyclooxygenase-2 in the renal medulla in maintaining blood pressure during high-salt intake.
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Affiliation(s)
- Tewabech Zewde
- Department of Physiology, Medical College of Wisconsin, Milwaukee 53226, USA
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Abstract
In the kidney, cyclooxygenase-2 (COX-2) is expressed in the macula densa/cTALH and medullary interstitial cells. The macula densa is involved in regulating afferent arteriolar tone and renin release by sensing alterations in luminal chloride via changes in the rate of Na(+)/K(+)/2Cl(-) cotransport, and administration of non-specific cyclooxygenase inhibitors will blunt increases in renin release mediated by macula densa sensing of decreases in luminal NaCl. High renin states [salt deficiency, angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers, diuretic administration or experimental renovascular hypertension] are associated with increased macula densa/cTALH COX-2 expression. Furthermore, there is evidence that angiotensin II and/or aldosterone may inhibit COX-2 expression. In AT1 receptor knockout mice, COX-2 expression is increased similar to increases with ACE inhibitors or AT1 receptor blockers. Direct administration of angiotensin II inhibits macula densa COX-2 expression. Previous studies demonstrated that alterations in intraluminal chloride concentration are the signal for macula densa regulation of tubuloglomerular feedback and renin secretion, with high chloride stimulating tubuloglomerular feedback and low chloride stimulating renin release. When cultured cTALH or macula densa cells were incubated in media with selective substitution of chloride ions, COX-2 expression and prostaglandin production were significantly increased. A variety of studies have indicated a role for COX-2 in the macula densa mediation of renin release. In isolated perfused glomerular preparations, renin release induced by macula densa perfusion with a low chloride solution was inhibited by a COX-2 inhibitor but not a COX-1 inhibitor. In vivo studies in rats indicated that increased renin release in response to low-salt diet, ACE inhibitor, loop diuretics or aortic coarctation could be inhibited by administration of COX-2-selective inhibitors. In mice with genetic deletion of COX-2, ACE inhibitors or low-salt diet failed to increase renal renin expression, although renin significantly increased in wild type mice. In contrast, in COX-1 null mice there were no significant differences in either the basal or ACE inhibitor-stimulated level of renal renin activity from plasma or renal tissue compared with wild type mice. In summary, there is increasing evidence that COX-2 expression in the macula densa and surrounding cortical thick ascending limb cells is regulated by angiotensin II and is a modulator of renal renin production. These interactions of COX-2 derived prostaglandins and the renin-angiotensin system may underlie physiological and pathophysiological regulation of renal function.
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Affiliation(s)
- R C Harris
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Schmidt H, Woodcock BG, Geisslinger G. Benefit-risk assessment of rofecoxib in the treatment of osteoarthritis. Drug Saf 2004; 27:185-96. [PMID: 14756580 DOI: 10.2165/00002018-200427030-00003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
NSAIDs are widely used to treat pain and inflammation in osteoarthritis. Their use in this indication is generally intermittent and fluctuates with the intensity of the disease. Nonetheless, success of the therapy is frequently limited by injury to the gastrointestinal mucosa and complications such as bleeding, ulceration and perforation. A careful and detailed evaluation of these aspects in regard to the newly introduced NSAIDs is of considerable clinical importance. This review focuses on the NSAID rofecoxib, one of the selective cyclo-oxygenase (COX)-2 inhibitors, which are claimed to be as effective as nonselective NSAIDs with better gastrointestinal tolerability. Indeed, phase II, phase III and epidemiological studies have revealed that the efficacy of rofecoxib is comparable to that of conventional NSAIDs but with lower gastrointestinal toxicity, although this advantage may not be demonstrable in every patient. In patients treated with low-dose aspirin (acetylsalicylic acid) for cardiovascular prophylaxis, celecoxib (another selective COX-2 inhibitor) seems to have no obvious advantages over conventional NSAIDs, and similar conclusions may be applied to rofecoxib. A comparison of NSAID therapy +/- concomitant low-dose aspirin was not a primary outcome in this trial with celecoxib and there is thus a need for further studies which compare the gastrointestinal risk of a selective COX-2 inhibitor plus aspirin versus a conventional NSAID. Recent debate has emerged regarding the cardiovascular safety of rofecoxib. Although there is evidence both for and against higher cardiovascular risk with rofecoxib, a retrospective cohort study recently published suggested that there is no increased risk of acute myocardial infarction in the short-term when compared with non-selective NSAIDs. The renal toxicity of rofecoxib has been thoroughly investigated. Clinical studies revealed renal effects of rofecoxib similar to those of conventional NSAIDs. Since adverse effects increase with the degree of renal impairment, monitoring of renal function should be carried out in patients at risk. Although there are still insufficient data concerning certain important adverse effects of rofecoxib, this drug is becoming an important alternative in the therapy of osteoarthritis, especially in high-risk patients. Clinicians need to weigh up the benefits and risks of rofecoxib on a case-by-base basis.
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Affiliation(s)
- Helmut Schmidt
- pharmazentrum frankfurt, Institute of Clinical Pharmacology, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany
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Höcherl K, Kees F, Krämer BK, Kurtz A. Cyclosporine A attenuates the natriuretic action of loop diuretics by inhibition of renal COX-2 expression. Kidney Int 2004; 65:2071-80. [PMID: 15149320 DOI: 10.1111/j.1523-1755.2004.00627.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND It is known that inhibition of cyclooxygenase (COX) impairs the renal actions of loop diuretics. Recently, we found that cyclosporine A (CsA) inhibits renal COX-2 expression. Therefore, we examined the interferences of CsA with the renal actions of loop diuretics. METHOD We investigated the renal effects of furosemide administration (12 mg/day subcutaneously) in male Sprague-Dawley rats receiving in addition vehicle, CsA (15 mg/kg x day), rofecoxib (10 mg/kg x day), or a combination of both. RESULTS CsA, rofecoxib, and their combination lowered the furosemide-induced increase of prostaglandin E(2) (PGE(2)) and of 6-keto prostaglandin F(1 alpha) (6-keto PGF(1 alpha)) excretion by 55% and by 70%. They also lowered furosemide stimulated renal excretion of sodium and water by about 65% and 60%. Basal as well as furosemide-induced stimulation of plasma renin activity (PRA) and of renal renin mRNA was further enhanced by CsA. In contrast, rofecoxib attenuated the furosemide-induced rise of PRA and of renin mRNA, both in the absence and in the presence of CsA. In addition, the increase in plasma 6-keto PGF(1 alpha) levels by furosemide was further enhanced by CsA and was attenuated by rofecoxib. CONCLUSION Taken together, our data suggest that CsA acts as an antinatriuretic, likely by the inhibition of COX-2-mediated renal prostanoid formation. Since the furosemide-induced stimulation of the renin system is not attenuated by CsA but by COX-2 inhibition, we speculate that extrarenal COX-2-derived prostanoids may be involved in the stimulation of the renin system by CsA and by loop diuretics.
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Affiliation(s)
- Klaus Höcherl
- Institut für Pharmakologie, Innere Medizin II and Physiologie, Universität Regensburg, Regensburg, Germany.
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Krämer BK, Kammerl MC, Kömhoff M. Renal Cyclooxygenase-2 (Cox-2). Kidney Blood Press Res 2004; 27:43-62. [PMID: 14691350 DOI: 10.1159/000075811] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2003] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The role of COX-2 for renal function during renal development, for physiology and pathophysiology of renal diseases and the side effects of available COX-2 inhibitors, has gained increasing interest. We aimed therefore to review the respective role of renal COX-2. METHODS Review of relevant recent publications in the field, and in addition of in part unpublished data obtained in our laboratories. RESULTS COX-2 is 'constitutively' localized in the kidney i.e. in macula densa, TALH, interstitial cells, and is of utmost importance for normal renal development. Renal COX-2 is regulated by for example sodium and volume intake, angiotensin II, glucocorticoids often involving specific COX-2 promotor response elements. COX-2 derived prostanoids are required for preservation of renal blood flow and glomerular filtration especially in states of fluid deficit, they promote natriuresis, and furthermore may stimulate renin secretion during low-sodium intake/loop diuretic use. Conversely, COX-2 inhibitors decrease glomerular filtration, and renal perfusion, sometimes even causing acute renal failure. In addition, COX-2 inhibitors cause sodium retention, edema formation, cardiac failure and hypertension. The role of COX-2 derived prostanoids in renal inflammation or failure including diabetic nephropathy and renal transplantation remains at present controversial. CONCLUSION COX-2 is one of the major players in renal physiology and pathophysiology. One focus of future work should be placed on COX-2 in primary renal diseases.
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Affiliation(s)
- Bernhard K Krämer
- Nephrologie, Klinik und Poliklinik für Innere Medizin II, Regensburg, Germany.
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Abstract
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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Affiliation(s)
- Hui-Fang Cheng
- Division of Nephrology, S 3322 MCN, Vanderbilt University School of Medicine, Nashville, TN 37232-2372, USA
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Wagner C, Vitzthum H, Castrop H, Schumacher K, Bucher M, Albertin S, Coffman TM, Arendshorst WJ, Kurtz A. Differential regulation of renin and Cox-2 expression in the renal cortex of C57Bl/6 mice. Pflugers Arch 2003; 447:214-22. [PMID: 14504926 DOI: 10.1007/s00424-003-1157-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2003] [Accepted: 07/21/2003] [Indexed: 12/13/2022]
Abstract
Based on the controversy about the relevance of cyclooxygenase-2 (Cox-2)-derived prostanoids from the macula densa for the control of the renin system, this study aimed to determine the interrelation between Cox-2 and renin expression in the mouse kidney. In control mice renin mRNA was readily detectable whilst renocortical Cox-2 mRNA abundance was at the detection limit of the RNase protection assay and no specific signals for Cox-2 were obtained by in situ hybridization or Western blot analysis. Experimental maneuvers such as low-salt diet, treatment with loop diuretics or angiotensin I converting enzyme inhibitors clearly increased renin mRNA abundance up to sevenfold, but under none of these conditions renocortical Cox-2 mRNA levels were significantly changed. Moreover, the strong stimulation of renin expression by angiotensin I-converting enzyme inhibition was not changed by the cyclooxygenase inhibitor ibuprofen, which in turn clearly lowered tissue prostanoid content. Our data suggest a marked divergence of renin and Cox-2 expression in the kidney cortex of C57Bl/6 mice with no clear evidence for a role of Cox-2-derived prostanoids from the macula densa in the regulation of renin expression.
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Affiliation(s)
- Charlotte Wagner
- Department of Physiology, University of Regensburg, 93040 Regensburg, Germany.
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Sorensen CM, Leyssac PP, Skott O, Holstein-Rathlou NH. NO mediates downregulation of RBF after a prolonged reduction of renal perfusion pressure in SHR. Am J Physiol Regul Integr Comp Physiol 2003; 285:R329-38. [PMID: 12714352 DOI: 10.1152/ajpregu.00063.2003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the study was to investigate mechanisms underlying the downregulation of renal blood flow (RBF) after a prolonged reduction in renal perfusion pressure (RPP) in adult spontaneously hypertensive rats (SHR). We tested the effect on the RBF response of clamping plasma ANG II in sevoflurane-anesthetized SHR. We also tested the effect of general cyclooxygenase (COX) inhibition and inhibition of the inducible COX-2. Furthermore, we assessed the effect of clamping the nitric oxide (NO) system. A prolonged period (15 min) of reduced RPP induced a downregulation of RBF. This was unchanged after clamping of plasma ANG II concentrations, general COX inhibition, and specific inhibition of COX-2. In contrast, clamping the NO system diminished the ability of SHR to downregulate RBF to a lower level. The downregulation of RBF was not associated with a resetting of the lower limit of autoregulation in the control group, in the ANG II-clamped group, or the NO clamped group. However, general COX inhibition and specific COX-2 inhibition enabled downward resetting of the lower limit of autoregulation. In conclusion, in SHR the renin-angiotensin system does not appear to play a major role in the downregulation of RBF after prolonged reduction of RPP. This response appears to be mediated partly by the NO system. We hypothesize that, in SHR, lack of downward resetting of the lower limit of autoregulation in response to a prolonged lowering of RPP could be the result of increased COX-2-mediated production of vasoconstrictory prostaglandins.
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López R, Roig F, Llinás MT, Salazar FJ. Role of cyclooxygenase-2 in the control of renal haemodynamics and excretory function. ACTA PHYSIOLOGICA SCANDINAVICA 2003; 177:429-35. [PMID: 12648160 DOI: 10.1046/j.1365-201x.2003.01103.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIM The available evidence supporting the importance of cyclooxygenase-2 (COX-2) in the regulation of renal haemodynamics and excretory function is summarized. Cyclooxygenase-2-derived metabolites play a very important role in regulating renal haemodynamics when sodium intake is low whereas it plays a minor role in the control of cortical blood flow when sodium intake is normal or elevated. The importance of COX-2 in the regulation of renal haemodynamics seems to be dependent on the endogenous production of other vasoactive products such as nitric oxide (NO) or noradrenaline. The activation of COX-2 in response to a decrease in NO may represent a mechanism aimed at defending the renal vasculature in the face of a decrease in NO levels. CONCLUSION Contrary to the important role of COX-2 in the long-term regulation of renal haemodynamics, the metabolites derived from COX-2 seem to be only involved in the acute regulation of renal excretory function.
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Affiliation(s)
- R López
- Department of Physiology, School of Medicine, University of Murcia, Murcia, Spain
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Castrop H, Klar J, Wagner C, Hocherl K, Kurtz A. General inhibition of renocortical cyclooxygenase-2 expression by the renin-angiotensin system. Am J Physiol Renal Physiol 2003; 284:F518-24. [PMID: 12441308 DOI: 10.1152/ajprenal.00338.2002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Because across-the-board data indicate that renin and cyclooxygenase-2 (COX-2) expression in the kidney cortex are regulated in parallel and because ANG II can inhibit COX-2 expression, the purpose of our study was to characterize a potential general inhibitory feedback of the renin-angiotensin system on renocortical COX-2 expression in vivo. Rats were fed a high-, normal-, or low-salt diet or were chronically infused with furosemide (60 mg. kg(-1). day(-1)) or the left renal artery was clipped, and the animals were treated in addition to or without the angiotensin-converting enzyme inhibitor ramipril (10 mg. kg(-1). day(-1)). A high-salt diet reduced expression of COX-2, whereas a low-salt diet, furosemide infusion, and renal artery stenosis stimulated COX-2 expression. Additional angiotensin-converting enzyme inhibition led to further increases in renocortical COX-2 expression by 62, 136, 300, 50, and 70% for a high-, normal-, and low-salt diet, furosemide infusion, and renal artery stenosis, respectively. Thus our data suggest a general inhibitory effect of the renin-angiotensin system on renocortical COX-2 expression.
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Affiliation(s)
- Hayo Castrop
- Institut für Physiologie und Pharmakologie der Universität Regensburg, D-93040 Regensburg, Germany
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Harding P, Glass WF, Scherer SD. COX-2 inhibition potentiates the antiproteinuric effect of enalapril in uninephrectomized SHR. Prostaglandins Leukot Essent Fatty Acids 2003; 68:17-25. [PMID: 12538086 DOI: 10.1016/s0952-3278(02)00231-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PGE(2) and PGI(2) reduce extracellular matrix deposition and their production is altered after ACE inhibitor (ACEi) treatment. We therefore hypothesized that cyclooxygenase (COX)-2 inhibition would exacerbate renal injury and antagonize the effects of ACEi. To test these hypotheses, WKY and SHR were uninephrectomized (UNX) and treated with either vehicle, enalapril, NS398 or enalapril+NS398. NS398 did not affect systolic blood pressure nor antagonize the antihypertensive effect of enalapril. Urinary protein excretion in UNX WKY was significantly decreased after treatment with either enalapril or NS398. In UNX SHR, enalapril reduced proteinuria, but NS398 alone had no effect. Administration of both drugs, however, further reduced proteinuria. In UNX WKY, treatment with either NS398 alone or both drugs reduced glomerular volume and similar results were observed in SHR. Surprisingly, these results disprove our original hypothesis and suggest that inhibition of COX-2 provides additional renoprotection to that of enalapril alone.
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Affiliation(s)
- Pamela Harding
- Department of Pathology and Anatomy, Eastern Virginia Medical School, 700 Olney Road, Norfolk, VA 23501, USA.
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37
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38
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Roig F, Llinás MT, López R, Salazar FJ. Role of cyclooxygenase-2 in the prolonged regulation of renal function. Hypertension 2002; 40:721-8. [PMID: 12411468 DOI: 10.1161/01.hyp.0000036451.76323.29] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The role of cyclooxygenase-2 (COX-2) in the prolonged regulation of renal function was evaluated during changes in sodium intake and reduction of NO synthesis. It was evaluated in conscious dogs by administering a selective inhibitor (nimesulide) during 8 consecutive days. Nimesulide administration to dogs with normal or high sodium load did not modify glomerular filtration rate but reduced renal blood flow (16%; P<0.05). The vasoconstriction elicited by COX-2 inhibition was greater when NO production was inhibited because glomerular filtration rate decreased by >25% when nimesulide was administered to dogs with a reduced NO synthesis. During low sodium intake, COX-2 inhibition elicited a decrease (P<0.05) of both glomerular filtration rate (34%) and renal blood flow (31%). Sodium excretion only decreased (P<0.05) during the first day of COX-2 inhibition in dogs with normal or high sodium load. The increase in plasma potassium levels elicited by COX-2 inhibition was greater in dogs with low sodium intake and was enhanced when NO production was inhibited. This change in potassium was not secondary to a decrease in plasma aldosterone levels. The results of this study suggest that COX-2-derived metabolites (1) play a more important role in the long-term regulation of renal hemodynamic when sodium intake is low, (2) protect the renal vasculature from the vasoconstriction secondary to a reduction in NO, (3) are only acutely involved in regulating urinary sodium excretion, and (4) play a more important role in regulating plasma potassium concentration when NO synthesis is reduced.
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Affiliation(s)
- Francisco Roig
- Departamento de Fisiología, Facultad de Medicina, Murcia, Spain
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Höcherl K, Dreher F, Vitzthum H, Köhler J, Kurtz A. Cyclosporine A suppresses cyclooxygenase-2 expression in the rat kidney. J Am Soc Nephrol 2002; 13:2427-36. [PMID: 12239231 DOI: 10.1097/01.asn.0000031702.86799.b9] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
On the basis of recent evidence that the cyclooxygenase-2 (COX-2) gene promoter contains functional binding sites for the nuclear factor of activated T cells (NFAT) and that COX-2 is expressed in a regulated fashion in the kidney, this study aimed to assess the effect of immunosuppressants on COX-2 expression in the kidney. Therefore, Wistar-Kyoto rats were treated with cyclosporine A (CsA; 15 mg/kg per day) or tacrolimus (5 mg/kg per day) for 7 d each. Both drugs markedly lowered COX-2 expression while COX-1 expression remained unaltered. Furthermore, CsA blunted the increase of renocortical COX-2 expression in response to low salt intake or a combination of low-salt diet with the ACE inhibitor ramipril (10 mg/kg per day), which strongly stimulates renocortical COX-2 expression. At the same time, calcineurin inhibitors moderately enhanced basal as well as stimulated renin secretion and renin gene expression. These findings suggest that inhibition of calcineurin could be a crucial determinant for the regulated expression of COX-2 in the kidney. Inhibition of COX-2 expression may therefore at least in part account for the well-known adverse effects of immunosuppressants in the kidney. Moreover, our data suggest that the stimulation of the renin system by low salt and by ACE inhibitors is not essentially mediated by COX-2 activity.
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Affiliation(s)
- Klaus Höcherl
- Institut für Pharmakologie, University of Regensburg, Regensburg, Germany.
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40
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Cheng HF, Wang SW, Zhang MZ, McKanna JA, Breyer R, Harris RC. Prostaglandins that increase renin production in response to ACE inhibition are not derived from cyclooxygenase-1. Am J Physiol Regul Integr Comp Physiol 2002; 283:R638-46. [PMID: 12184998 DOI: 10.1152/ajpregu.00150.2002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is well known that nonselective, nonsteroidal anti-inflammatory drugs inhibit renal renin production. Our previous studies indicated that angiotensin-converting enzyme inhibitor (ACEI)-mediated renin increases were absent in rats treated with a cyclooxygenase (COX)-2-selective inhibitor and in COX-2 -/- mice. The current study examined further whether COX-1 is also involved in mediating ACEI-induced renin production. Because renin increases are mediated by cAMP, we also examined whether increased renin is mediated by the prostaglandin E(2) receptor EP(2) subtype, which is coupled to G(s) and increases cAMP. Therefore, we investigated if genetic deletion of COX-1 or EP(2) prevents increased ACEI-induced renin expression. Age- and gender-matched wild-type (+/+) and homozygous null mice (-/-) were administered captopril for 7 days, and plasma and renal renin levels and renal renin mRNA expression were measured. There were no significant differences in the basal level of renal renin activity from plasma or renal tissue in COX-1 +/+ and -/- mice. Captopril administration increased renin equally [plasma renin activity (PRA): +/+ 9.3 +/- 2.2 vs. 50.1 +/- 10.9; -/- 13.7 +/- 1.5 vs. 43.9 +/- 6.6 ng ANG I x ml(-1) x h(-1); renal renin concentration: +/+ 11.8 +/- 1.7 vs. 35.3 +/- 3.9; -/- 13.0 +/- 3.0 vs. 27.8 +/- 2.7 ng ANG I x mg protein(-1) x h(-1); n = 6; P < 0.05 with or without captopril]. ACEI also increased renin mRNA expression (+/+ 2.4 +/- 0.2; -/- 2.1 +/- 0.2 fold control; n = 6-10; P < 0.05). Captopril led to similar increases in EP(2) -/- compared with +/+. The COX-2 inhibitor SC-58236 blocked ACEI-induced elevation in renal renin concentration in EP(2) null mice (+/+ 24.7 +/- 1.7 vs. 9.8 +/- 0.4; -/- 21.1 +/- 3.2 vs. 9.3 +/- 0.4 ng ANG I x mg protein(-1) x h(-1); n = 5) as well as in COX-1 -/- mice (SC-58236-treated PRA: +/+ 7.3 +/- 0.6; -/- 8.0 +/- 0.9 ng ANG I x ml(-1) x h(-1); renal renin: +/+ 9.1 +/- 0.9; -/- 9.6 +/- 0.5 ng ANG I x mg protein(-1) x h(-1); n = 6-7; P < 0.05 compared with no treatment). Immunohistochemical analysis of renin expression confirmed the above results. This study provides definitive evidence that metabolites of COX-2 rather than COX-1 mediate ACEI-induced renin increases. The persistent response in EP(2) nulls suggests involvement of prostaglandin E(2) receptor subtype 4 and/or prostacyclin receptor (IP).
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Affiliation(s)
- Hui-Fang Cheng
- George M. O'Brien Kidney Disease Center, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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41
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Höcherl K, Kammerl MC, Schumacher K, Endemann D, Grobecker HF, Kurtz A. Role of prostanoids in regulation of the renin-angiotensin-aldosterone system by salt intake. Am J Physiol Renal Physiol 2002; 283:F294-301. [PMID: 12110513 DOI: 10.1152/ajprenal.00347.2001] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the effect of cyclooxygenase (COX) activity on the regulation of the renin-angiotensin-aldosterone system by salt intake. Therefore, Sprague-Dawley rats were subjected to different salt diets [0.02, 0.6, and 8% NaCl (wt/wt)] and treated with the selective COX-2 inhibitor rofecoxib (10 mg x kg body wt(-1) x day(-1)) or with ketorolac at a dose selective for COX-1 inhibition (2 mg x kg body wt(-1) x day(-1)) for 3, 7, 14, and 21 days. Rofecoxib and ketorolac caused a similar reduction of renocortical PGE2 formation with a low-salt diet. Rofecoxib did not change plasma renin activity or renocortical renin mRNA abundance with any of the diets but clearly lowered plasma aldosterone concentration. In contrast, ketorolac delayed the increase in plasma renin activity and of renin mRNA in response to low salt intake but did not change plasma aldosterone concentration. Prolonged treatment with rofecoxib but not with ketorolac caused an upregulation of COX-2 expression while COX-1 mRNA abundance remained unchanged. These findings suggest that COX-1-derived, but not COX-2-derived, prostanoids are of relevance for the regulation of the renin system by salt intake.
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Affiliation(s)
- Klaus Höcherl
- Institut für Pharmakologie, der Universität Regensburg, D-93040 Regensburg, Germany.
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42
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Höcherl K, Endemann D, Kammerl MC, Grobecker HF, Kurtz A. Cyclo-oxygenase-2 inhibition increases blood pressure in rats. Br J Pharmacol 2002; 136:1117-26. [PMID: 12163344 PMCID: PMC1573449 DOI: 10.1038/sj.bjp.0704821] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1 It is known that nonselective cyclo-oxygenase (COX) inhibitors have small but significant effects on blood pressure (BP), most notably in hypertensive patients on antihypertensive medication. Whether selective COX-2 inhibitors also interfere with BP regulation is not well understood. Therefore, we aimed to examine the effect of chronic treatment with a selective COX-2 inhibitor (rofecoxib) on systolic blood pressure (sBP) in normotensive Wistar-Kyoto rats (WKY) and on the developmental changes of sBP in young spontaneously hypertensive rats (SHR). In addition, we investigated a possible influence of salt intake on the effects of COX-2 inhibition on BP in these two rat strains. 2 Rofecoxib dose dependently increased sBP and decreased plasma levels of 6-keto prostaglandin (PG)F(1alpha) in WKY rats fed a normal salt diet (0.6% NaCl, wt wt(-1)), without affecting serum thromboxane (TX)B(2) levels. 3 Rofecoxib significantly elevated sBP in both rat strains fed normal salt or high salt diet (8% NaCl, wt wt(-1)), but not in rats on low salt intake (0.02% NaCl, wt wt(-1)). 4 Rofecoxib significantly decreased plasma levels of 6-keto PGF(1alpha) in both rat strains fed normal or high salt diet, but not in rats during low salt intake. 5 Rofecoxib exerted no influence on the changes of body weight nor on water intake. Plasma renin activity (PRA) and renocortical renin mRNA abundance were not changed by rofecoxib, but plasma aldosterone concentration (PAC) was significantly reduced. 6 These results suggest that chronic inhibition of COX-2 causes an increase of blood pressure that depends on prostacyclin synthesis. Furthermore, this increase is independent on genetic predisposition and can be prevented by salt deprivation. Since water intake and body weight gain were not changed by rofecoxib, fluid retention appears not to be a major reason for the development of hypertension. Similarly, an activation of the renin-angiotensin-aldosterone axis appears to be an unlikely candidate mechanism.
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Affiliation(s)
- Klaus Höcherl
- Institut für Pharmakologie, Universitätsstr. 31, 93040 Regensburg, Germany.
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43
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Beierwaltes WH. Cyclooxygenase-2 products compensate for inhibition of nitric oxide regulation of renal perfusion. Am J Physiol Renal Physiol 2002; 283:F68-72. [PMID: 12060588 DOI: 10.1152/ajprenal.00364.2001] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cyclooxygenase (COX)-2 is in the macula densa, cosegregating with neuronal nitric oxide synthase (nNOS). It is hypothesized that in response to acute inhibition of NOS, the influence of COX-2-derived prostanoids is exaggerated, compensating for renal vasoconstriction. Blood pressure (BP) and renal blood flow (RBF) were measured after selective COX-2 inhibition with NS-398 followed by NOS inhibition with L-nitro arginine methyl ester (L-NAME) or after L-NAME followed by NS-398. BP was 106 +/- 4 mmHg and was unaffected by NS-398. L-NAME after NS-398 increased BP by 27 +/- 2 mmHg, decreased RBF by one-half, and doubled renal vascular resistance (RVR; P < 0.001). Initial L-NAME increased BP by 26 +/- 3 mmHg (P < 0.001) and decreased RBF by 44% (P < 0.001), doubling RVR. After L-NAME, NS-398 induced a further 7 +/- 3-mmHg rise in BP (P < 0.05), decreased RBF by 20% (P < 0.025), and increased RVR by 23% (P < 0.01). The constrictor response to COX-2 inhibition after L-NAME could not be duplicated by either selective nNOS inhibition or NOS-independent renal vasoconstriction. Acute NOS inhibition unmasked renal vasoconstriction with COX-2 inhibition, suggesting that the influence of COX-2-derived vasodilator eicosanoids is exaggerated to maintain renal perfusion, compensating for the acute loss of NO.
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Affiliation(s)
- William H Beierwaltes
- Hypertension and Vascular Research Division, Henry Ford Hospital, Detroit, Michigan 48202-2689, USA.
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Abstract
Cyclo-oxygenase (COX) is one of the key enzymes in the biosynthesis of prostaglandins. Two isoforms of this enzyme COX-1 and COX-2 are known to exist. Among other functions, prostaglandins play an important role in the protection of the gastric mucosa and maintenance of renal function in pathophysiological conditions which would otherwise threaten it. Conventional nonsteroidal anti-inflammatory drugs (NSAIDs) block prostaglandin synthesis, resulting in gastric mucosal injury and renal dysfunction in susceptible individuals. The recent introduction of selective COX-2 inhibitors, celecoxib and rofecoxib, appear to induce less gastrointestinal morbidity. Although conclusive data are still lacking, there is evidence to suggest that COX-2 antagonists may be capable of causing some of the same renal syndromes seen in association with the older, less selective NSAIDs.
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Affiliation(s)
- Gary Noroian
- Department of Medicine, Division of Renal Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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45
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Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used drugs with potential effects on systemic blood pressure. NSAIDs act by inhibiting synthesis of prostaglandins (PGs) from arachidonic acid via cyclooxygenase (COX)-1 and COX-2, the 2 isoforms of COX. NSAIDs may affect blood pressure via the renin-angiotensin pathway, alterations in sodium and water retention in the kidneys, inhibition of vasodilating PGs, and production of various vasoconstricting factors, including endothelin-1 and P450-mediated metabolites of arachidonic acid. In 2 meta-analyses, it was found that NSAIDs have small but significant effects on blood pressure, most notably in hypertensive patients on antihypertensive medication. NSAIDs cause small (<5 mm Hg) elevations in systolic blood pressure, and little or no change in diastolic blood pressure. The incidence rates of hypertension and peripheral edema were low, ranging from <1% to >9% of patients. The incidence and levels of hypertension associated with COX-2 inhibitors are within the range of those observed with nonspecific NSAIDs. Apparent differences between the COX-2 inhibitors celecoxib and rofecoxib may be functions of differences in study population susceptibilities to NSAID-mediated hypertensive effects. Patients at risk for hypertension should be monitored for changes in blood pressure during NSAID treatment.
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Affiliation(s)
- William H Frishman
- Department of Medicine, New York Medical College, Valhalla, New York 10595, USA.
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Kammerl MC, Nüsing RM, Richthammer W, Krämer BK, Kurtz A. Inhibition of COX-2 counteracts the effects of diuretics in rats. Kidney Int 2001; 60:1684-91. [PMID: 11703585 DOI: 10.1046/j.1523-1755.2001.00988.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND It is well established that the diuretic- and renin-stimulated effects of loop diuretics can be attenuated by nonselective cyclooxygenase inhibitors. Since it is yet unclear which of the isoforms of cyclooxygenases, COX-1 and COX-2, is relevant in this context, our study aimed to determine the effects of selective COX-2 inhibition on the renal effects of the loop diuretic furosemide, as well as the diuretic hydrochlorothiazide, which acts on the distal tubule. METHOD Male Sprague-Dawley rats were treated with furosemide (12 mg/day subcutaneously by osmotic pump) or hydrochlorothiazide (30 mg/kg body weight/day orally by gavage). In addition, parallel groups received rofecoxib (1 to 10 mg/kg body weight/day) for selective inhibition of COX-2. Controls were treated with vehicle. RESULTS Induction of COX-2 mRNA expression due to furosemide was paralleled by increased renal excretion of prostanoids. Also, hydrochlorothiazide led to a rise in prostanoid excretion. Rofecoxib blunted the diuretic-induced increase in prostanoid excretion, thus confirming an effective blockade of COX-2. Moreover, the COX-2 inhibitor rofecoxib dose-dependently attenuated diuresis and saluresis, as well as the stimulation of the renin system induced by furosemide. Furthermore, rofecoxib completely reversed diuresis and saluresis and prevented the increase of plasma renin activity induced by hydrochlorothiazide. CONCLUSIONS These findings suggest that COX-2-derived prostanoids are of major relevance in modulating the renal effects of diuretics. COX-2 inhibitors might be valuable drugs to treat salt and water wasting during Bartter and Gitelman diseases.
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Affiliation(s)
- M C Kammerl
- Institut für Physiologie I, Universität Regensburg, Universitätstrasse 31, 93053 Regensburg, Germany.
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47
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Schnermann J. Cyclooxygenase-2 and macula densa control of renin secretion. Nephrol Dial Transplant 2001; 16:1735-8. [PMID: 11522847 DOI: 10.1093/ndt/16.9.1735] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J Schnermann
- National Institute of Diabetes, Digestive and Kidney Disease, NIH, Building 10, 10 Center Drive MSC 1370, Bethesda, MD 20892, USA
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