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Sontag F, Suvakov S, Garovic VD. Soluble urinary somatic angiotensin converting enzyme is overexpressed in patients with preeclampsia: a potential new marker for the disease? Hypertens Pregnancy 2022; 41:190-197. [PMID: 35997304 PMCID: PMC9771896 DOI: 10.1080/10641955.2022.2115060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 08/15/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE The aim of this study was to identify and quantify urinary Angiotensin-Converting-Enzyme (ACE) in hypertensive disorders of pregnancy. METHODS Urine samples were analyzed by Western blot. Patients were classified into: normotensive pregnancy (N); preeclampsia and superimposed preeclampsia (PE+SPE); and gestational hypertension (GH). RESULTS Somatic ACE protein expression was higher in PE+SPE compared to N and GH. There was a positive correlation between ACE and urinary protein to creatinine ratio, systolic and diastolic blood pressures. CONCLUSION These results indicate ACE overexpression in the urine of preeclamptic patients and suggest that it may be a new marker for the disease.
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Affiliation(s)
- Fernando Sontag
- Division of Nephrology & Hypertension, Mayo Clinic, Rochester, MN USA
- Postgraduate Program in Medicine and Health Sciences, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS Brazil
- Postgraduate Program in Translational Medicine, Department of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Sonja Suvakov
- Division of Nephrology & Hypertension, Mayo Clinic, Rochester, MN USA
| | - Vesna D Garovic
- Division of Nephrology & Hypertension, Mayo Clinic, Rochester, MN USA
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Aimo A, Vergaro G, Passino C, Clerico A. Evaluation of pathophysiological relationships between renin-angiotensin and ACE-ACE2 systems in cardiovascular disorders: from theory to routine clinical practice in patients with heart failure. Crit Rev Clin Lab Sci 2021; 58:530-545. [PMID: 34196254 DOI: 10.1080/10408363.2021.1942782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Despite the progressive improvements in diagnosis and therapy during the first 20 years of this century, the morbidity and mortality of patients with heart failure (HF) remain high, resulting in an enormous health and economic burden. Only a further improvement in understanding the pathophysiological mechanisms related to the development of cardiac injury and dysfunction can allow more innovative and personalized approaches to HF management. The renin-angiotensin system (RAS) has a critical role in cardiovascular physiology by regulating blood pressure and electrolyte balance. The RAS is mainly regulated by both angiotensin converting enzyme (ACE) and type 2 angiotensin converting enzyme (ACE2). However, the balance between the various peptides and peptidases constituting the RAS/ACE pathway remains in great part unraveled in patients with HF. This review summarizes the role of the RAS/ACE axis in cardiac physiology and HF pathophysiology as well as some analytical issues relevant to the clinical and laboratory assessment of inter-relationships between these two systems. There is evidence that RAS peptides represent a dynamic network of peptides, which are altered in different HF states and influenced by medical therapy. However, the mechanisms of signal transduction have not been fully elucidated under physiological and pathophysiological conditions. Further investigations are necessary to explore novel molecular mechanisms related to the RAS, which will provide alternative therapeutic agents. Moreover, monitoring the circulating levels of active RAS peptides in HF patients may enable a personalized approach by facilitating assessment of the pathophysiological status of several cardiovascular diseases and thus better selection of therapies for HF patients.
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Affiliation(s)
- Alberto Aimo
- Fondazione CNR - Regione Toscana G. Monasterio, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Giuseppe Vergaro
- Fondazione CNR - Regione Toscana G. Monasterio, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Claudio Passino
- Fondazione CNR - Regione Toscana G. Monasterio, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Aldo Clerico
- Fondazione CNR - Regione Toscana G. Monasterio, Scuola Superiore Sant'Anna, Pisa, Italy
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Krauspenhar B, Sontag F, Ronchi FA, Casarini DE, Poli-de-Figueiredo CE, Pinheiro da Costa BE. Angiotensin Converting Enzyme 90 kDa isoform: Biomarker for diagnosis of preeclampsia? Med Hypotheses 2014; 83:526-9. [PMID: 25257705 DOI: 10.1016/j.mehy.2014.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 09/10/2014] [Indexed: 10/24/2022]
Abstract
Preeclampsia (PE), one of the leading gestational hypertensive diseases, is characterized by increased blood pressure (⩾140/90mmHg) and pathological proteinuria after 20weeks gestation. It is a complex, multifactorial syndrome with an unestablished etiology and cure. The search continues for a biomarker that could assist in the early prediction or diagnosis of PE, reducing the rate of maternal and fetal mortality. Based on the findings of Casarini et al. that suggest the 90kDa isoform of the Angiotensin Converting Enzyme (ACE) as a possible marker of hypertension, we hypothesized that this isoform may be present in pregnant women with PE, since they present a transient and spontaneous model of systemic arterial hypertension in pregnancy. We believe, therefore, that pregnant women with pure PE (PPE) express the ACE 90kDa isoform in urine, as well as having elevated isoform enzymatic activity, during pregnancy only. Postpartum, with the normalization of blood pressure, the protein isoform would no longer be expressed. Pregnant women with superimposed preeclampsia (SPE) would present the ACE 90kDa isoform both during and after the gestation period, and its enzymatic activity would remain high as they are chronically hypertensive. It is expected that normotensive pregnant women do not present this isoform in their urine as elevated blood pressure levels do not occur. Both normotensive and PPE affected pregnant women with a family history of hypertension, will possibly express the ACE 90kDa isoform before pregnancy and may become hypertensive, only after some years, through the influence of environmental factors and/or other diseases. If our hypothesis is confirmed, it will allow differentiation of PPE and SPE sooner than 12weeks postpartum, which is currently the estimated period for confirmation of the specific diagnosis. Furthermore, it could be an early biomarker for predicting the disease, enabling the physician to choose the best clinical management. In addition, it would minimize the use of other methods as the biological sample for obtaining the marker is urine, a practical and effective test with good reproducibility. Finally, test results would enable a greater understanding of the mechanisms involved in gestational hypertension.
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Affiliation(s)
- Bruna Krauspenhar
- Graduate Program in Medicine and Health Sciences (Nephrology), School of Medicine, Institute of Biomedical Research, São Lucas Hospital, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
| | - Fernando Sontag
- Graduate Program in Medicine and Health Sciences (Nephrology), School of Medicine, Institute of Biomedical Research, São Lucas Hospital, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Fernanda A Ronchi
- Nephrology Division, Department of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Dulce E Casarini
- Nephrology Division, Department of Medicine, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Carlos Eduardo Poli-de-Figueiredo
- Graduate Program in Medicine and Health Sciences (Nephrology), School of Medicine, Institute of Biomedical Research, São Lucas Hospital, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Bartira E Pinheiro da Costa
- Graduate Program in Medicine and Health Sciences (Nephrology), School of Medicine, Institute of Biomedical Research, São Lucas Hospital, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil
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N-domain isoform of Angiotensin I converting enzyme as a marker of hypertension: populational study. Int J Hypertens 2012; 2012:581780. [PMID: 22666552 PMCID: PMC3362081 DOI: 10.1155/2012/581780] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 03/05/2012] [Indexed: 01/28/2023] Open
Abstract
The aim of this paper was to investigate the presence of the urinary 90 kDa N-domain ACE in a cohort of the population from Vitoria, Brazil, to verify its association with essential hypertension since this isoform could be a possible genetic marker of hypertension. Anthropometric, clinical, and laboratory parameters of the individuals were evaluated (n = 1150) and the blood pressure (BP) was measured. The study population was divided according to ACE isoforms in urine as follows: ACE 65/90/190, presence of three ACE isoforms (n = 795), ACE 90+ (65/90) (n = 186), and ACE 90− (65/190) (n = 169) based on the presence (+) or absence (−) of the 90 kDa ACE isoform. The anthropometric parameters, lipid profile, serum levels of uric acid, glucose, and the systolic and diastolic BP were significantly greater in the ACE 90+ compared with the ACE 90− and ACE 65/90/190 individuals. We found that 98% of individuals from the ACE 90+ group and 38% from the ACE 65/90/190 group had hypertension, compared to only 1% hypertensive individuals in the ACE 90− group. There is a high presence of the 90 kDa N-domain ACE isoform (85%) in the studied population. The percentile of normotensive subjects with three isoforms was 62%. Our findings could contribute to the development of new efficient strategy to prevent and treat hypertension to avoid the development of cardiovascular disease.
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de Andrade MCC, Affonso R, Fernandes FB, Febba AC, da Silva IDCG, Stella RCR, Marson O, Jubilut GN, Hirata IY, Carmona AK, Corradi H, Acharya KR, Sturrock ED, Casarini DE. Spectroscopic and structural analysis of somatic and N-domain angiotensin I-converting enzyme isoforms from mesangial cells from Wistar and spontaneously hypertensive rats. Int J Biol Macromol 2010; 47:238-43. [PMID: 20435057 DOI: 10.1016/j.ijbiomac.2010.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 04/23/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
Angiotensin I-converting enzyme (ACE) plays a key role in the renin-angiotesin aldosterone cascade. We analysed the secondary structure and structural organization of a purified 65kDa N-domain ACE (nACE) from Wistar rat mesangial cells, a 90 kDa nACE from spontaneously hypertensive rats and a 130 kDa somatic ACE. The C-terminal alignment of the 65 kDa nACE with rat ACE revealed that the former was truncated at Ser(482), and the sequence of the 90 kDa nACE ended at Pro(629). Protein's secondary structure consisted predominantly of alpha-helices. The 90 and 65 kDa isoforms were the most stable in guanidine and at low pH, respectively. Enzymatic activity decreased with loss in secondary structure, except in the case of guanidine HCl where the 90 kDa fragment loses its secondary structure faster than its enzymatic activity. We identified and characterized the activity and stability of these isoforms and these findings would be helpful on the understanding of the role of nACE isoforms in hypertension.
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Affiliation(s)
- Maria C C de Andrade
- Departamento de Medicina, Disciplina de Nefrologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Botucatu Street 740, Zip Code 04023-900, SP, São Paulo, Brazil
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Simultaneous determination of ACE activity with 2 substrates provides information on the status of somatic ACE and allows detection of inhibitors in human blood. J Cardiovasc Pharmacol 2008; 52:90-103. [PMID: 18645413 DOI: 10.1097/fjc.0b013e31817fd3bc] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Angiotensin I-converting enzyme (ACE), a key enzyme in cardiovascular pathophysiology, consists of 2 homologous domains, each bearing a Zn-dependent active site. The ratio of the rates of hydrolysis of 2 synthetic substrates, Z-Phe-His-Leu (ZPHL) and Hip-His-Leu (HHL), is characteristic for each type of ACE: somatic 2-domain 1, N-domain 4.5, and C-domain 0.7 (Williams et al, 1996). We hypothesized that inactivation or selective inhibition of the C-domain within the somatic ACE should increase the ratio from 1 toward higher values, whereas inactivation or inhibition of the N-domain should decrease the ratio to lower values. Temperatures in the 40-60 degrees C range cause preferential inactivation of the C-domain in somatic ACE and an increase in the ZPHL/HHL ratio. Determination of the ZPHL/HHL ratio in freshly 100-fold concentrated urine ruled out the existence of the N-domain fragment in human urine, which appears only as a result of long storage. Inhibition of ACE by common inhibitors also increases the ZPHL/HHL ratio for 2-domain ACE, thus providing a sensitive method for the detection of ACE inhibitors in biological fluids. Therefore, simultaneous measurements of ACE activity with 2 substrates (ZPHL and HHL) and calculation of their ratio allow us to monitor the status of the ACE molecule and detect ACE inhibitors (endogenous and exogenous) in human blood and other biological fluids. This method should find wide application in monitoring clinical trials with ACE inhibitors and in the development of the approach for personalized medicine by these effective drugs.
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Renal Modulation: The Renin-Angiotensin-Aldosterone System (RAAS). NEPHROLOGY AND FLUID/ELECTROLYTE PHYSIOLOGY: NEONATOLOGY QUESTIONS AND CONTROVERSIES 2008. [PMCID: PMC7152415 DOI: 10.1016/b978-1-4160-3163-5.50013-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Expression of angiotensin I-converting enzymes and bradykinin B2 receptors in mouse inner medullary-collecting duct cells. Int Immunopharmacol 2007; 8:254-60. [PMID: 18182236 DOI: 10.1016/j.intimp.2007.09.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 09/06/2007] [Accepted: 09/06/2007] [Indexed: 11/21/2022]
Abstract
We described in mouse inner medullary-collecting duct cells (mIMCD-3) the somatic and the N-domain ACE synthesis and its interaction with the kallikrein-kinin system co-localized in the same cells. We purified two ACE forms from culture medium, M1 (130 kDa) and M2 (N-domain, 60 kDa), and cellular lysate, C1 (130 kDa) and C2 (N-domain, 60 kDa). Captopril and enalaprilat inhibited the purified enzymes. The immunofluorescence studies indicated that ACE is present in the membrane, cytoplasm and in the cell nucleus. Kinin B1 and B2 receptors were detected by immunofluorescence and showed to be activated by BK and DesR9 BK, increasing the acidification rate which was enhanced in the presence of enalaprilat. The presence of secreted and intracellular ACE in mIMCD-3 confirmed the hypothesis previously proposed by our group for a new site of ACE secretion in the collecting duct.
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Role of ACE, ACE2 and Neprilysin in the Kidney. FRONTIERS IN RESEARCH OF THE RENIN-ANGIOTENSIN SYSTEM ON HUMAN DISEASE 2007. [PMCID: PMC7122178 DOI: 10.1007/978-1-4020-6372-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Lopes Del Ben G, Redublo Quinto BM, Casarini DE, Bueno Ferreira LC, Sousa Ayres S, de Abreu Carvalhaes JT. The urinary activity of angiotensin-converting enzyme in preterm, full-term newborns, and children. Pediatr Nephrol 2006; 21:1138-43. [PMID: 16810513 DOI: 10.1007/s00467-006-0160-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 03/14/2006] [Accepted: 03/17/2006] [Indexed: 11/25/2022]
Abstract
The urinary activity of the angiotensin-converting enzyme (U(ACE)) is not yet completely documented in human neonates. We measured the U(ACE) in 36 premature neonates on the 1st day and in the 1st, 2nd, 3rd, and 4th weeks of life, in 22 full-term neonates between the 1st and 2nd days, and in 30 nursing and preschool children between 1 month and 6 years of age. The urinary excretion of sodium (U(Na)/U(Cr)) and the potassium/sodium index (U(K)/U(Na)) were analyzed in the neonates. U(ACE) was greater in premature than in full-term neonates and greater in both than in older children (p<0.001). In the premature neonates, U(ACE) peaked at the 2nd week, the U(Na)/U(Cr) index decreased, and the U(K)/U(Na) index increased between the 1st day and the 2nd week (p<0.001). The U(Na)/U(Cr) index on the 1st day and in the 1st and 2nd weeks was greater in premature than in full-term neonates (p<0.001). There was no significant correlation between the U(ACE) and the U(Na)/U(Cr) index. In conclusion, the U(ACE) profile was shown to be age dependent and related to the postnatal renal development. The increase in U(ACE) activity may reflect the high activity of the neonatal intrarenal renin-angiotensin system (RAS).
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Affiliation(s)
- Graziela Lopes Del Ben
- Pediatric Nephrology Division, Department of Pediatrics, Paulista Medical School, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
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Camargo de Andrade MC, Di Marco GS, de Paulo Castro Teixeira V, Mortara RA, Sabatini RA, Pesquero JB, Boim MA, Carmona AK, Schor N, Casarini DE. Expression and localization of N-domain ANG I-converting enzymes in mesangial cells in culture from spontaneously hypertensive rats. Am J Physiol Renal Physiol 2006; 290:F364-75. [PMID: 16106038 DOI: 10.1152/ajprenal.00110.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The angiotensin-converting enzyme (ACE) profile in urine of hypertensive patients and spontaneously hypertensive rats (SHR; 90- and 65-kDa N-domain ACEs) is different from that of healthy subjects and Wistar rats (190 and 65 kDa). In addition, four ACE isoforms were purified from mesangial cells (MC) of Wistar rats in the intracellular compartment (130 and 68 kDa) and as secreted forms (130 and 60 kDa). We decided to characterize ACE forms from SHR MC in culture. Analysis of the ACE gene showed that SHR MC are able to express ACE mRNA. The concentrated medium and cell homogenate were separately purified by gel filtration and then subjected to lisinopril-Sepharose chromatography. The molecular masses of purified enzymes, 90 kDa for ACEm1A and 65 kDa for ACEm2A (secreted enzymes) and 90 kDa for ACEInth1A and 65 kDa for ACEInth2A (intracellular), were different from those of Wistar MC. The purified enzymes are Cl−dependent, inhibited by enalaprilat and captopril, and able to hydrolyze AcSDKP. Immunofluorescence and cell fractionation followed by Western blotting showed predominant immunoreaction of the 9B9 antiserum for N-domain ACE in the nuclei. The N-domain ACE was localized in the glomerulus from Wistar rats and SHR. ANG II and ANG-(1–7) were localized in the cell cytoplasm and nuclei. The 90-kDa N-domain ACE, described recently as a possible genetic marker of hypertension, was found inside the cell nuclei of SHR MC colocalized with ANG II and ANG-(1–7). The presence of ANG II in the cell nuclei could suggest an important role for this peptide in the transcription of new genes.
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Affiliation(s)
- Maria Claudina Camargo de Andrade
- Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Medicina, Disciplina de Nefrologia, Rua Botucatu, 740, CEP 04023-900, São Paulo, SP, Brazil
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Levitt DG, Schoemaker RC. Human physiologically based pharmacokinetic model for ACE inhibitors: ramipril and ramiprilat. BMC CLINICAL PHARMACOLOGY 2006; 6:1. [PMID: 16398929 PMCID: PMC1373666 DOI: 10.1186/1472-6904-6-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Accepted: 01/06/2006] [Indexed: 12/28/2022]
Abstract
Background The angiotensin-converting enzyme (ACE) inhibitors have complicated and poorly characterized pharmacokinetics. There are two binding sites per ACE (high affinity "C", lower affinity "N") that have sub-nanomolar affinities and dissociation rates of hours. Most inhibitors are given orally in a prodrug form that is systemically converted to the active form. This paper describes the first human physiologically based pharmacokinetic (PBPK) model of this drug class. Methods The model was applied to the experimental data of van Griensven et. al for the pharmacokinetics of ramiprilat and its prodrug ramipril. It describes the time course of the inhibition of the N and C ACE sites in plasma and the different tissues. The model includes: 1) two independent ACE binding sites; 2) non-equilibrium time dependent binding; 3) liver and kidney ramipril intracellular uptake, conversion to ramiprilat and extrusion from the cell; 4) intestinal ramipril absorption. The experimental in vitro ramiprilat/ACE binding kinetics at 4°C and 300 mM NaCl were assumed for most of the PBPK calculations. The model was incorporated into the freely distributed PBPK program PKQuest. Results The PBPK model provides an accurate description of the individual variation of the plasma ramipril and ramiprilat and the ramiprilat renal clearance following IV ramiprilat and IV and oral ramipril. Summary of model features: Less than 2% of total body ACE is in plasma; 35% of the oral dose is absorbed; 75% of the ramipril metabolism is hepatic and 25% of this is converted to systemic ramiprilat; 100% of renal ramipril metabolism is converted to systemic ramiprilat. The inhibition was long lasting, with 80% of the C site and 33% of the N site inhibited 24 hours following a 2.5 mg oral ramipril dose. The plasma ACE inhibition determined by the standard assay is significantly less than the true in vivo inhibition because of assay dilution. Conclusion If the in vitro plasma binding kinetics of the ACE inhibitor for the two binding sites are known, a unique PBPK model description of the Griensven et. al. experimental data can be obtained.
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Affiliation(s)
- David G Levitt
- Department of Physiology, University of Minnesota, 6-125 Jackson Hall, 321 Church St. S. E., Minneapolis, MN 55455, USA
| | - Rik C Schoemaker
- Centre for Human Drug Research Zernikedreef 10, 2333CL Leiden, The Netherlands
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Ferrario CM, Averill DB, Brosnihan KB, Chappell MC, Iskandar SS, Dean RH, Diz DI. Vasopeptidase inhibition and Ang-(1-7) in the spontaneously hypertensive rat. Kidney Int 2002; 62:1349-57. [PMID: 12234305 DOI: 10.1111/j.1523-1755.2002.kid559.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Omapatrilat, a new vasopeptidase inhibitor, inhibits the activity of angiotensin-converting enzyme (ACE) and neutral endopeptidase 24.11 (NEP). Because these two enzymes participate in the degradation of the vasodilator and natriuretic peptide, angiotensin-(1-7) [Ang-(1-7)], we assessed whether omapatrilat treatment is associated with changes in the plasma and urinary excretion rates of the angiotensins. METHODS We investigated in spontaneously hypertensive rats (SHR) (0.24 kg body weight) the effect of omapatrilat on plasma and urinary concentrations of angiotensin (Ang) I, Ang II and Ang-(1-7) during 17 days of administration of either the drug (N = 15, 100 micromol/kg/day) or vehicle (N = 14) in the drinking water. Hemodynamic and renal excretory function studies were associated with histological examination of the expression of Ang-(1-7) in the kidneys of both vehicle and omapatrilat-treated SHRs. RESULTS Omapatrilat induced a sustained lowering of systolic blood pressure (-68 mm Hg) without changes in cardiac rate. The mild positive water balance produced by omapatrilat did not cause natriuresis or kaliuresis, although it was associated with a significant decrease in urine osmolality. Blood pressure normalization was accompanied by increases in plasma Ang I (2969%), Ang II (57%), and Ang-(1-7) (163%) levels, paralleling pronounced increases in urinary excretion rates of Ang I and Ang-(1-7) but not Ang II. Detection of Ang-(1-7) immunostaining in the kidneys of five other SHR exposed either to vehicle (N = 3) or omapatrilat (N = 2) ascertained the source of the Ang-(1-7) found in the urine. Intense Ang-(1-7) staining, more pronounced in omapatrilat-treated SHR, was found in renal proximal tubules throughout the outer and inner regions of the renal cortex and the thick ascending loop of Henle, whereas no Ang-(1-7)-positive immunostaining was found in glomeruli and distal tubules. CONCLUSIONS Omapatrilat antihypertensive effects caused significant activation of the renin-angiotensin system associated with increases in urinary excretion rates of Ang I and Ang-(1-7). Combined studies of Ang-(1-7) metabolism in urine and immunohistochemical studies in the kidney revealed the existence of an intrarenal source, which may account for the pronounced increase in the excretion rate of the vasodilator heptapeptide. These findings provide further evidence for a contribution of Ang-(1-7) to the regulation of renal function and blood pressure.
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Affiliation(s)
- Carlos M Ferrario
- The Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Ferrario CM, Smith RD, Brosnihan B, Chappell MC, Campese VM, Vesterqvist O, Liao WC, Ruddy MC, Grim CE. Effects of omapatrilat on the renin-angiotensin system in salt-sensitive hypertension. Am J Hypertens 2002; 15:557-64. [PMID: 12074359 DOI: 10.1016/s0895-7061(02)02268-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The contribution of angiotensin-(1-7) [Ang-(1-7)] to the antihypertensive actions of omapatrilat, a novel vasopeptidase inhibitor, was evaluated in 22 salt-sensitive, low renin, hypertensive subjects as a substudy of a multicenter randomized, double-blind, parallel study of 4 weeks duration. A total of 25 other subjects received lisinopril as the active control. Omapatrilat (40 mg) produced sustained control of blood pressure (BP) (as assessed by 24-h ambulatory BP measurements) that was significantly greater than that produced by 20 mg daily of lisinopril. The antihypertensive response to either drug was accompanied by similar sustained inhibition of angiotensin converting enzyme activity. Plasma levels of angiotensin I (Ang I), angiotensin II (Ang II) and Ang-(1-7) were not altered by treatment with either omapatrilat or lisinopril, even though both regimens produced a modest rise in plasma renin activity. In contrast, urinary excretion rates of Ang I and Ang-(1-7) but not Ang II increased significantly throughout the dosing period of subjects who were given omapatrilat, whereas the smaller antihypertensive response produced by lisinopril had a smaller and transient effect on increasing urinary excretion rates of Ang-(1-7). Omapatrilat, being a single molecule inhibiting neutral endopeptidase and converting enzyme simultaneously, controlled salt-sensitive hypertension by a mechanism that was associated with sustained increases in urinary Ang-(1-7) excretion. We suggest that Ang-(1-7) may be a component of the mechanisms by which omapatrilat induces an antihypertensive response in salt sensitive hypertension.
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Affiliation(s)
- Carlos M Ferrario
- Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
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