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Windt WAKM, Prakash J, Kok RJ, Moolenaar F, Kluppel CA, de Zeeuw D, van Dokkum RPE, Henning RH. Renal targeting of captopril using captopril-lysozyme conjugate enhances its antiproteinuric effect in adriamycin-induced nephrosis. J Renin Angiotensin Aldosterone Syst 2016; 5:197-202. [PMID: 15803438 DOI: 10.3317/jraas.2004.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Introduction High-sodium intake blunts the renoprotective efficacy of angiotensin-converting enzyme (ACE) inhibitors. We investigated whether targeting the drug to the kidneys may attenuate the inferior response to ACE inhibitor (ACE-I) under high-sodium conditions. The ACE-I, captopril, was coupled to the low molecular weight protein (LMWP) lysozyme, yielding captopril-lysozyme conjugates that accumulate specifically in the proximal tubular cells of the kidneys.We compared the antiproteinuric efficacy of captopril to that of the captopril-lysozyme conjugate in adriamycin-induced proteinuric rats fed with a high-sodium diet. Materials and methods Rats with adriamycin (single injection 2 mg/kg)-induced proteinuria were put on a high-sodium diet (HS; 3% NaCl). When stable proteinuria developed at 5.5 weeks, animals were assigned to the following subcutaneous treatments: (1) vehicle (n=7); (2) lysozyme (equivalent to the amount in conjugate) (n=7); (3) captopril (5 mg/kg/24 hours) (n=8); (4) captopril-lysozyme conjugate (captopril content equivalent to 1mg captopril/kg/24 hours) (n=7). Blood pressure and proteinuria were monitored. After 10 days of treatment the rats were sacrificed and kidneys and plasma were removed. Results Results are given as mean + S.E.M. After injection with adriamycin at t=0, stable proteinuria developed, amounting to 547+79 mg/24 hours at week 5.5. Subsequently, after seven and nine days of treatment, no reduction of proteinuria was observed in the captopril-treated group. In contrast, a significant reduction in proteinuria, amounting to 35+4% (day seven) and 25+2% (day nine), was observed in the captopril-lysozyme conjugate group (p<0.05 compared with the captopril group). In contrast, blood pressure was reduced in the captopril-treated group by 13.9+2.9 mmHg, while in the captopril-lysozyme treated group, an increase of 7.9+3.3 mmHg was found. Renal ACE activity was lowered by 30% in the captopril, as well as in the captopril-lysozyme conjugate treated group, compared with control. Furthermore, the ratio of kidney: plasma levels of captopril almost doubled as a consequence of coupling to lysozyme. Conclusion In proteinuric rats fed with a high-sodium diet, captopril induced a reduction in blood pressure without an effect on proteinuria. In contrast, renal targeting of a five times lower dose of the ACE-I with the captopril-lysozyme conjugate reduced proteinuria without reducing blood pressure. Therefore, renal targeting of ACE-I may be a promising strategy to optimise the therapeutic response of ACE-I.
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Affiliation(s)
- Willemijn A K M Windt
- Department of Clinical Pharmacology, Groningen University, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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de Borst MH, Navis G. Sodium intake, RAAS-blockade and progressive renal disease. Pharmacol Res 2016; 107:344-351. [DOI: 10.1016/j.phrs.2016.03.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/25/2016] [Accepted: 03/30/2016] [Indexed: 12/16/2022]
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Patel SN, Ali Q, Hussain T. Angiotensin II Type 2-Receptor Agonist C21 Reduces Proteinuria and Oxidative Stress in Kidney of High-Salt-Fed Obese Zucker Rats. Hypertension 2016; 67:906-15. [PMID: 27021008 DOI: 10.1161/hypertensionaha.115.06881] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/03/2016] [Indexed: 12/18/2022]
Abstract
Oxidative and nitrosative stress have been implicated in high-sodium diet (HSD)-related hypertensive renal injury. In this study, we investigated angiotensin II type 2-receptor-mediated renoprotection in obese Zucker rats fed HSD. Obese Zucker rats were fed normal sodium diet or HSD 4%, for 14 days, with/without angiotensin II type 2-receptor agonist C21, delivered subcutaneously via osmotic pump, 1 mg/kg per day. Compared with normal sodium diet controls, HSD rats exhibited increase in cortical nicotinamide adenine dinucleotide phosphate oxidase activity, urinary H2O2, and 8-isoprostanes, which were associated with severe glomerulosclerosis, interstitial fibrosis, decline in estimated glomerular filtration rate, and an increase in urinary leak and activity of N-acetyl-β-D-glucosaminidase, a lysosomal enzyme and a marker of tubular damage. These changes were improved by C21 treatment. Cortical expression of endothelial nitric oxide synthase, phospho-endothelial nitric oxide synthase (Ser(1177)), and plasma nitrites were reduced after HSD intake, whereas nitrosative stress (3-nitrotyrosine) and enzymatic defense (superoxide dismutase-to-catalase activity) remained unaltered. However, C21 preserved plasma nitrites in HSD-fed obese Zucker rat. C21 treatment reduced protein-to-creatinine, albumin-to-creatinine, as well as fractional excretion of protein and albumin in HSD-fed obese Zucker rat, which is independent of changes in protein recycling receptors, megalin, and cubilin. HSD intake also altered renal excretory and reabsorptive capacity as evident by elevated plasma urea nitrogen-to-creatinine and fractional excretion of urea nitrogen, and reduced urine-to-plasma creatinine, which were modestly, but insignificantly, improved by C21 treatment. Together results demonstrate that angiotensin II type 2-receptor activation protects against HSD-induced kidney damage in obesity plausibly by reducing nicotinamide adenine dinucleotide phosphate oxidase activity and rescuing nitrites.
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Affiliation(s)
- Sanket N Patel
- From the Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX
| | - Quaisar Ali
- From the Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX
| | - Tahir Hussain
- From the Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX.
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Mirkovic K, Frenay ARS, van den Born J, van Goor H, Navis G, de Borst MH. Sodium restriction potentiates the renoprotective effects of combined vitamin D receptor activation and angiotensin-converting enzyme inhibition in established proteinuric nephropathy. Nephrol Dial Transplant 2015; 32:1293-1301. [DOI: 10.1093/ndt/gfv304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 07/11/2015] [Indexed: 01/02/2023] Open
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Keyzer CA, de Jong MA, Fenna van Breda G, Vervloet MG, Laverman GD, Hemmelder M, Janssen WM, Lambers Heerspink HJ, Navis G, de Borst MH. Vitamin D receptor activator and dietary sodium restriction to reduce residual urinary albumin excretion in chronic kidney disease (ViRTUE study): rationale and study protocol. Nephrol Dial Transplant 2015; 31:1081-7. [PMID: 25744274 DOI: 10.1093/ndt/gfv033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/18/2015] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Optimal albuminuria reduction is considered essential to halting chronic kidney disease (CKD) progression. Both vitamin D receptor activator (VDRA) treatment and dietary sodium restriction potentiate the efficacy of renin-angiotensin-aldosterone-system (RAAS) blockade to reduce albuminuria. The ViRTUE study addresses whether a VDRA in combination with dietary sodium restriction provides further albuminuria reduction in non-diabetic CKD patients on top of RAAS blockade. The ViRTUE study is an investigator-initiated, prospective, multi-centre, randomized, double-blind (paricalcitol versus placebo), placebo-controlled trial targeting stage 1-3 CKD patients with residual albuminuria of >300 mg/day due to non-diabetic glomerular disease, despite angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use. During run-in, all subjects switched to standardized RAAS blockade (ramipril 10 mg/day) and blood pressure titrated to <140/90 mmHg according to a standardized protocol. Eligible patients are subsequently enrolled and undergo four consecutive study periods in random order of 8 weeks each: (i) paricalcitol (2 µg/day) combined with a liberal sodium diet (∼200 mmol Na(+)/day, i.e. mean sodium intake in the general population), (ii) paricalcitol (2 µg/day) combined with dietary sodium restriction (target: 50 mmol Na(+)/day), (iii) placebo combined with a liberal sodium diet and (iv) placebo combined with dietary sodium restriction. Data are collected at the end of each study period. The primary outcome is 24-h urinary albumin excretion. Secondary study outcomes are blood pressure, renal function (estimated glomerular filtration rate), plasma renin activity and, in a sub-population (N = 9), renal haemodynamics (measured glomerular filtration rate and effective renal plasma flow). A sample size of 50 patients provides 90% power to detect a 23% reduction in albuminuria, assuming a 25% dropout rate. Further reduction of residual albuminuria by combination of VDRA treatment and sodium restriction during single-agent RAAS-blockade will justify long-term studies on cardiorenal outcomes and safety. CLINICAL TRIAL REGISTRATION NTR2898 (Dutch trial register).
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Affiliation(s)
- Charlotte A Keyzer
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Maarten A de Jong
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - G Fenna van Breda
- Department of Nephrology and Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Marc G Vervloet
- Department of Nephrology and Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Gozewijn D Laverman
- Department of Internal Medicine, Division of Nephrology, ZGT Hospital, Almelo, The Netherlands
| | - Marc Hemmelder
- Department of Internal Medicine, Division of Nephrology, Medical Center Leeuwarden, Leeuwarden, The Netherlands
| | - Wilbert M Janssen
- Department of Internal Medicine, Division of Nephrology, Martini Hospital Groningen, Groningen, The Netherlands
| | - Hiddo J Lambers Heerspink
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Gerjan Navis
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Martin H de Borst
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Pfister M, Martin NE, Haskell LP, Barrett JS. Optimizing Dose Selection with Modeling and Simulation: Application to the Vasopeptidase Inhibitor M100240. J Clin Pharmacol 2013; 44:621-31. [PMID: 15145970 DOI: 10.1177/0091270004265365] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Dual inhibition of neutral endopeptidase 24.11 (NEP) and angiotensin-converting enzyme (ACE) has gained increasing interest in the treatment of hypertension, heart failure, and renoprotection. Specifically, M100240, the thioester of the dual ACE/NEP inhibitor MDL100,173, has been evaluated in the management of hypertension. A model-based analysis, including simulations, was employed to characterize the relationship between individual M100240 drug exposure and neurohormonal response and to optimize the dose selection for future clinical studies. Sixty-two healthy subjects and 189 hypertensive patients were studied after oral once-daily administration of 2.5, 5, 10, 25, or 50 mg M100240. Pharmacokinetic-biomarker and blood pressure response models were fitted to the data with the computer program NONMEM. A direct inhibitory E(max) model adequately described the relationship between MDL100,173 concentration and ACE activity. No clear concentration or dose-dependent NEP or blood pressure responses were evident. Given a target 90% ACE inhibition, simulation reveals that (1). 50 mg M100240 once daily produces adequate ACE inhibition 24 hours postdose in only 20% of subjects, and (2). higher and/or more frequent doses on the order of 25 mg three times daily or 50 mg twice daily are required to achieve the target ACE inhibition in at least 50% of patients over 24 hours. Insufficient blood pressure-lowering effects were observed in healthy subjects and hypertensive patients due to inadequate ACE and NEP inhibition with once-daily oral doses of up to 50 mg of M100240. Divided doses might provide target ACE inhibition in more patients.
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Affiliation(s)
- Marc Pfister
- Aventis Pharmaceuticals, 1041 Route 202-206, Bridgewater, NJ 08807, USA
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Dimitropoulos N, Papakyriakou A, Dalkas GA, Sturrock ED, Spyroulias GA. A computational approach to the study of the binding mode of dual ACE/NEP inhibitors. J Chem Inf Model 2010; 50:388-96. [PMID: 20170101 DOI: 10.1021/ci9005047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Combined blockade of the renin-angiotensin-aldosterone system (RAAS) is an attractive therapeutic strategy for the treatment of cardiovascular diseases. Vasopeptidase inhibitors are a group of compounds capable of inhibiting more than one enzyme, which leads to potentiation of natriuretic peptide actions and suppression of the RAAS. In this study, molecular modeling has been used to elucidate key structural features that govern the binding and/or selectivity of a single compound toward the zinc catalytic sites of the N- and C-domains of the angiotensin-converting enzyme (ACE) and the neutral endopeptidase (NEP). Eleven dual inhibitors were categorized in three classes, according to their zinc binding groups. Analysis of their docked conformers revealed the molecular environment of the catalytic sites and the specific interactions between the inhibitors and amino acid residues that are important for selectivity and cooperativity. In addition, inhibitors were predicted to bind to the C-domain of the ACE with greater affinity than the N-domain, with an average difference in the free energy of binding approximately 2-3 kcal mol(-1). Residues that were identified to actively participate in the binding and stabilizing of the enzyme-inhibitor complexes were analyzed in a consensus way for both the ACE and the NEP. These atomic-level insights into enzyme-ligand binding can be used to drive new structure-based drug design processes in the quest for more selective and effective vasopeptidase inhibitors.
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Takahashi K, Hirose T, Mori N, Morimoto R, Kohzuki M, Imai Y, Totsune K. The renin-angiotensin system, adrenomedullins and urotensin II in the kidney: possible renoprotection via the kidney peptide systems. Peptides 2009; 30:1575-85. [PMID: 19477209 DOI: 10.1016/j.peptides.2009.05.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 05/18/2009] [Accepted: 05/18/2009] [Indexed: 01/29/2023]
Abstract
The incidence of chronic kidney disease, such as diabetic nephropathy, is increasing throughout the world. Many biologically active peptides play important roles in the kidney. The classical example is the renin-angiotensin system (RAS). Angiotensin II plays critical roles in the progression of chronic kidney disease through its vasoconstrictor action, stimulatory action on cell proliferation, and reactive oxygen-generating activity. A renin inhibitor, aliskiren, has recently been shown to be a clinically effective drug to reduce proteinuria in patients with diabetic nephropathy. (Pro)renin receptor, a specific receptor for renin and prorenin, was newly identified as a member of the RAS. When bound to prorenin, (pro)renin receptor activates the angiotensin I-generating activity of prorenin in the absence of cleavage of the prosegment, and directly stimulates the pathway of mitogen-activated protein kinase independently from the RAS. The kidney peptides that antagonize the intrarenal RAS may have renoprotective actions. Adrenomedullins, potent vasodilator peptides, have been shown to have renoprotective actions. On the other hand, urotensin II, a potent vasoconstrictor peptide, may promote the renal dysfunction in chronic kidney disease together with the renal RAS. Thus, in addition to the renin inhibitor and (pro)renin receptor, adrenomedullins and urotensin II may be novel targets to develop therapeutic strategies against chronic kidney disease.
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Affiliation(s)
- Kazuhiro Takahashi
- Department of Endocrinology and Applied Medical Science, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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Daull P, Jeng AY, Battistini B. Towards triple vasopeptidase inhibitors for the treatment of cardiovascular diseases. J Cardiovasc Pharmacol 2007; 50:247-56. [PMID: 17878751 DOI: 10.1097/fjc.0b013e31813c6ca5] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cardiovascular diseases (CDs) are among the most encountered pathologies in western countries; with obesity reaching pandemic proportions, they are soon to become a worldwide problem. High blood pressure is the main risk factor for CDs, and its tight control is an imperative for the treatment of complications such as renal diseases, heart failure, and atherosclerosis. Blood homeostasis and vascular tone are regulated through at least 3 major closely interrelated pathways in which zinc metallopeptidases modulate the concentration of vasoactive mediators. Those extensively studied vasopeptidases were therefore rapidly targeted with specific inhibitors in order to control the levels of vasoconstrictors [angiotensin II (AII) and endothelin-1 (ET-1)] and vasodilators [bradykinin (BK) and atrial natriuretic peptide (ANP)], thereby controlling blood pressure. The first class of inhibitors to be developed were against angiotensin-converting enzyme (ACE), recently followed by dual inhibitors of ACE/neprylisin (NEP), NEP/endothelin-converting enzyme (ECE), and finally triple ACE/NEP/ECE inhibitors. The dual and triple inhibitors are defined as vasopeptidase inhibitors (VPI). In addition to their ability to effectively lower blood pressure in hypertensive patients, drugs targeting these enzymes also displayed antiinflammatory and antifibrotic activities. The major point emerging from recent studies undertaken to improve the management of CDs is that the combined action of different therapeutic strategies (ie, simultaneous modulation of several neurohumoral mediators) shows better results than conservative therapeutic approaches. In this review, we historically present the advances made in the comprehension of the different mechanisms of blood pressure regulation and some of the drugs that arose from this understanding.
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Hamming I, Navis G, Kocks MJA, van Goor H. ACE inhibition has adverse renal effects during dietary sodium restriction in proteinuric and healthy rats. J Pathol 2006; 209:129-39. [PMID: 16532430 DOI: 10.1002/path.1956] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Angiotensin-converting enzyme inhibitors (ACEi) provide renoprotection. A low sodium diet enhances their efficacy. However, the added effect of sodium restriction on proteinuria and blood pressure is not invariably associated with better preservation of renal morphology, suggesting that the combination of ACEi with a low sodium diet can elicit renal structural abnormalities. To test this hypothesis, the effects of ACEi in combination with a control (CS) or a low sodium (LS) diet were investigated in healthy rats and in adriamycin nephrotic rats. After 3 weeks of treatment, rats were sacrificed and kidneys examined for renal structural abnormalities. In healthy rats, ACEi reduced blood pressure: the fall in blood pressure was significantly greater in the ACEi/LS group. Renal morphology was normal in the ACEi/CS group but severe interstitial damage was found in the ACEi/LS group. This was associated with increased interstitial macrophage influx and up-regulation of osteopontin, alpha-smooth muscle actin, and collagen III expression. In addition, ACEi/LS induced an increase in the total medial area of afferent arterioles. In nephrotic rats, ACEi/LS reduced both blood pressure and proteinuria, whereas only blood pressure was reduced in the ACEi/CS group. Mild interstitial damage was present in the ACEi/CS group but, strikingly, pronounced tubulo-interstitial abnormalities occurred in the ACEi/LS group, similar to those seen in ACEi/LS healthy rats, with similar changes in afferent arteriolar walls. In conclusion, the combination of ACEi/LS elicits pronounced renal interstitial abnormalities in healthy and nephrotic rats, despite a significant reduction of proteinuria in the latter. Considering their occurrence in healthy rats, these renal adverse effects cannot be due to specific characteristics of adriamycin nephrosis. Further studies should elucidate the mechanisms underlying these observations and their impact on long-term renoprotection.
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Affiliation(s)
- I Hamming
- Department of Pathology and Laboratory Medicine, University Medical Center Groningen and University of Groningen, The Netherlands.
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van der Wouden EA, Henning RH, Deelman LE, Roks AJM, Boomsma F, de Zeeuw D. Does angiotensin (1-7) contribute to the anti-proteinuric effect of ACE-inhibitors. J Renin Angiotensin Aldosterone Syst 2006; 6:96-101. [PMID: 16470489 DOI: 10.3317/jraas.2005.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Angiotensin-converting enzyme inhibitors (ACE-I) reduce proteinuria and protect the kidney in proteinuric renal disease. During ACE-I therapy, circulating levels of angiotensin (1-7) [Ang (1-7)] are increased. As cardiac and renal protective effects of Ang (1-7) have been reported, we questioned whether Ang (1-7) contributes to the anti-proteinuric effects of ACE-I treatment. Therefore, we evaluated whether Ang (1-7) infusion reduces proteinuria in a rat model of adriamycin-induced renal disease. In addition, the effect of a selective Ang (1-7) blocker, [D-Ala7]-Ang (1-7) (A779), was investigated in rats treated with the ACE-I, lisinopril (LIS). Six weeks after induction of proteinuria, therapy was started in four different groups: control, Ang (1-7), LIS, and LIS+A779. After two weeks, the rats were sacrificed. Six weeks after injection of adriamycin, the rats had developed proteinuria of 323+/-40 mg/24 hours. The proteinuria remained stable in the control group and in the Ang (1-7) group, but was reduced in both LIS and LIS+A779-treated groups. Similarly, blood pressure (BP) was unchanged in the control and the Ang (1-7) groups, but reduced in both the LIS and the LIS+A779 groups. Plasma levels of Ang (1-7) were increased in the Ang (1-7) and in both LIS-treated groups. We conclude that systemic Ang (1-7) plays no major role in the anti-proteinuric and BPlowering effects of ACE-I in this rat model of adriamycin-induced nephrosis.
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Affiliation(s)
- Els A van der Wouden
- Department of Clinical Pharmocology, Division of Nephrology, Groningen University Institute for Drug Exploration (GUIDE), University Medical Center Groningen, Groningen, The Netherlands.
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Nakhoul F, Ramadan R, Khankin E, Yaccob A, Kositch Z, Lewin M, Assady S, Abassi Z. Glomerular abundance of nephrin and podocin in experimental nephrotic syndrome: different effects of antiproteinuric therapies. Am J Physiol Renal Physiol 2005; 289:F880-90. [PMID: 15942045 DOI: 10.1152/ajprenal.00451.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Nephrotic syndrome (NS) is a clinical state characterized by massive proteinuria, hypoalbuminemia, and eventual edema formation. Although the mechanisms underlying this phenomenon are not yet fully clarified, it is well accepted that nephrin and podocin are involved in the development of proteinuria. The effects of early treatment with various antiproteinuric therapies on proteinuria and glomerular staining of nephrin and podocin in rats with experimental NS have not been previously studied. Proteinuria and glomerular nephrin and podocin immunofluorescence were examined in rat kidneys with adriamycin-induced NS and the effects of antiproteinuric drug therapies during 5 wk with enalapril, losartan, alone or in combination, omapatrilat, and mycophenolate mofetil on these parameters were assessed. Injection of adriamycin caused a significant increase in daily (from 21.8 ± 1.4 to 983.1 ± 45.8 mg/day, P < 0.01) and cumulative protein excretion (from negligible values to 22,490 ± 931 mg, P < 0.001) during 5 wk. Early treatment with enalapril significantly decreased the daily (641.7 ± 82.4 mg/day, P < 0.0023) and cumulative proteinuria (15,727 ± 2,204 mg, P < 0.001). A similar effect, although to a lesser extent, was obtained after omapatrilat treatment: cumulative proteinuria was reduced to 18,706 ± 1,042 mg, P < 0.001. In contrast, losartan treatment did not significantly influence the cumulative proteinuria that remained comparable (20,351 ± 1,360 mg, P > 0.05) to that observed in untreated NS rats. Unexpectedly, when losartan was given in combination with enalapril, it abolished the beneficial effects of the latter. Pretreatment with mycophenolate mofetil exerted a moderate antiproteinuric effect, which appeared only during the last week of the experimental treatment. Nephrotic rats exhibited severe disruption of slit diaphragm structure as seen by rapid and profound loss of nephrin and podocin. Beneficial effects of enalapril, omapatrilat, and mycophenolate mofetil paralleled the preservation of nephrin, as determined immunohistochemically, and enabled prediction of significant antiproteinuric responses. Enalapril alone or in combination with losartan resulted in significant preservation of podocin. Pretreatment with enalapril, and to a lesser extent omapatrilat, is superior to losartan in reducing proteinuria in NS rats. A combination of ACE inhibitors with ANG II receptor blockers does not provide any advantageous antiproteinuric therapy in these animals. Nephrin loss is an indication of proteinuria in NS and the antiproteinuric effects of ACE inhibitors, vasopeptidase inhibitors, and mycophenolate mofetil attenuate this reduction. Not all the drugs which restore podocin reduce urinary protein in NS.
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Affiliation(s)
- Farid Nakhoul
- Dept. of Physiology and Biophysics, Faculty of Medicine, Technion, P.O. Box 9649, Haifa, 31096, Israel
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Ruilope LM. Vasopeptidase Inhibitors. Hypertension 2005. [DOI: 10.1016/b978-0-7216-0258-5.50161-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Worthley MI, Corti R, Worthley SG. Vasopeptidase inhibitors: will they have a role in clinical practice? Br J Clin Pharmacol 2004; 57:27-36. [PMID: 14678337 PMCID: PMC1884420 DOI: 10.1046/j.1365-2125.2003.01947.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The human cardiovascular system is regulated by haemodynamic, neurohumoral and structural mechanisms. The endothelium and the neurohumoral system play a key role in modulating both vascular tone and structure by producing vasoactive substances, and in the modulation of blood cell adhesion. Although the neurohormonal systems are essential in vascular homeostasis, they become maladaptive in conditions such as hypertension, coronary disease and heart failure. The clinical success of blocking the renin-angiotensin system by angiotensin converting enzyme (ACE)-inhibitors and the sympathetic nerve system by beta-blockers demonstrates the importance of neurohumoral blockade. The inadequate effect of angiotensin converting enzyme (ACE) or neutral endopeptidase (NEP) inhibitor monotherapy seen in some patients treated for hypertension or congestive heart failure, and the promising effect seen after their combination, led to the development of drugs that simultaneously inhibit both enzyme systems. Neutral endopeptidase, like ACE, is an endothelial cell surface zinc metallopeptidase with similar structure and catalytic site to ACE. NEP is the major enzymatic pathway for degradation of natriuretic peptides. The natriuretic peptide system can be viewed as the endogenous inhibitor of the renin angiotensin system. The dual metalloprotease inhibitors of ACE and NEP, called vasopeptidase inhibitors therefore represent a new and attractive therapeutic strategy for the treatment of cardiovascular disease. The ability to add incremental benefit over already proven therapy, with an acceptable side-effect profile however, is questionable in this new class of agents.
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