Plasma Soluble (Pro)Renin Receptor Is Independent of Plasma Renin, Prorenin, and Aldosterone Concentrations But Is Affected by Ethnicity Geneviève Nguyen, Anne Blanchard, Emmanuel Curis, Damien Bergerot, Yann Chambon, Takuo Hirose, Aurore Caumont-Prim, Sylvie Brailly Tabard, Stéphanie Baron, Michael Frank, Kazuhito Totsune and Michel Azizi Hypertension. 2014;63:297-302; originally published online November 11, 2013; doi: 10.1161/HYPERTENSIONAHA.113.02217 Hypertension is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 2013 American Heart Association, Inc. All rights reserved. Print ISSN: 0194-911X. Online ISSN: 1524-4563
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://hyper.ahajournals.org/content/63/2/297
Data Supplement (unedited) at: http://hyper.ahajournals.org/content/suppl/2013/11/11/HYPERTENSIONAHA.113.02217.DC1.html
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Renin–Angiotensin System Plasma Soluble (Pro)Renin Receptor Is Independent of Plasma Renin, Prorenin, and Aldosterone Concentrations But Is Affected by Ethnicity Geneviève Nguyen,* Anne Blanchard,* Emmanuel Curis, Damien Bergerot, Yann Chambon, Takuo Hirose, Aurore Caumont-Prim, Sylvie Brailly Tabard, Stéphanie Baron, Michael Frank, Kazuhito Totsune, Michel Azizi Abstract—A soluble (pro)renin receptor (sPRR) circulates in plasma and is able to bind renin and prorenin. It is not known whether plasma sPRR concentrations vary with the activity of the renin–angiotensin system. We measured plasma sPRR, renin, prorenin, and aldosterone concentrations in 121 white and 9 black healthy subjects, 40 patients with diabetes mellitus, 41 hypertensive patients with or without renin–angiotensin system blockers, 9 patients with primary aldosteronism, and 10 patients with Gitelman syndrome. Median physiological plasma sPRR concentration was 23.5 ng/mL (interquartile range, 20.9–26.5) under usual uncontrolled sodium diet. sPRR concentration in healthy subjects, unlike renin and prorenin, did not display circadian variation or dependence on age, sex, posture, or hormonal status. sPRR concentrations were ≈25% lower in black than in white subjects, whereas renin concentrations were ≈40% lower. Patients with diabetes mellitus (average renin–high prorenin levels) and with hypertension only (average renin–average prorenin levels) had sPRR concentrations similar to healthy subjects. Renin–angiotensin system blockade was associated with increase of sPRR concentration by ≈12%. sPRR in patients with primary aldosteronism (low renin–low prorenin) and Gitelman syndrome (high renin–high prorenin) were similar and ≈10% higher than in healthy subjects. There was no correlation between sPRR and renin or prorenin. In conclusion, our results show that plasma sPRR concentrations are dependent on ethnicity and independent of renin, prorenin, and aldosterone concentrations in healthy subjects and in patients with contrasted degrees of renin– angiotensin system activity. (Hypertension. 2014;63:297-302.) Online Data Supplement
•
Key Words: diabetes mellitus ◼ ethnology ◼ hyperaldosteronism ◼ hypertension, essential
M
ature active renin and its inactive precursor prorenin bind to the (pro)renin receptor (PRR).1 In addition to triggering intracellular signals, renin and prorenin binding to PRR increases their enzymatic activity.1 A soluble form of PRR (sPRR) is generated by intracellular cleavage by furin and is secreted in plasma.2 sPRR binds renin and prorenin2 and has been reported to activate prorenin.3 sPRR can be measured by ELISA,4 providing new opportunities for investigating the regulation of PRR synthesis and sPRR secretion. Increased PRR expression has been shown in failing hearts5 and sPRR variations have been reported during pregnancy,6,7 in patients with chronic kidney disease8 and with heart failure.9 However, it is not known whether plasma sPRR is influenced by physiological or pathological changes of the renin–angiotensin–aldosterone system (RAAS).
The objectives of our study were (1) to establish reference values for plasma sPRR concentrations in healthy subjects and to identify physiological factors associated with changes in these concentrations; and (2) to determine the relationships among plasma renin, prorenin, aldosterone, and sPRR concentrations in pathological conditions involving contrasted RAAS activation, type-2 diabetes mellitus (DM), essential hypertension, and primary and secondary hyperaldosteronism.
Subjects and Methods Subjects All subjects provided written informed consent to participate in the study. The protocol was approved by the Institutional Review Committee Comité de Protection des Personnes, Paris-Île de France
Received August 10, 2013; first decision August 27, 2013; revision accepted October 14, 2013. From the INSERM, U1050, Paris, France (G.N.); Collège de France, Center for Interdisciplinary Research in Biology, Paris, France (G.N., T.H.); CNRS, UMR 7241, Paris, France (G.N.); Université Paris Descartes, Faculté de Médecine, Sorbonne Paris Cité, Paris, France (A.B., Y.C., S.B., M.F., M.A.); Assistance Publique Hôpitaux de Paris (A.B., D.B., Y.C., S.B., M.F., M.A.) and INSERM, CIC 9201 (A.B., E.C., M.A.), Hôpital Européen Georges Pompidou, Centre d’Investigations Cliniques, Paris, France; Laboratoire de biomathématiques, EA 4466, Faculté de pharmacie, Université Paris Descartes, Sorbonne Paris Cité, Paris, France (E.C.); Department of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Seiryo-machi, Aoba-ku, Sendai, Miyagi, Japan (T.H.); Assistance Publique—Hôpitaux de Paris, Hôpital européen Georges-Pompidou, Unité d’Épidémiologie et de Recherche Clinique, Paris, France (A.C.-P.); INSERM, Centre D’investigation Épidémiologique, Paris, France (A.C.-P.); Assistance Publique Hôpitaux de Paris, Hôpital Kremlin Bicêtre, Laboratoire d’Hormonologie, Le Kremlin-Bicêtre, France (S.B.T.); and Department of Social Welfare, Faculty of Synthetic Welfare, Tohoku Fukushi University, Kunimi, Aoba-ku, Sendai, Japan (K.T.). *These authors contributed equally to this work. The online-only Data Supplement is available with this article at http://hyper.ahajournals.org/lookup/suppl/doi:10.1161/HYPERTENSIONAHA. 113.02217/-/DC1. Correspondence to Genevieve Nguyen, Centre for Interdisciplinary Research in Biology, UMR INSERM U1050/CNRS 7241, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05. E-mail [email protected] © 2013 American Heart Association, Inc. Hypertension is available at http://hyper.ahajournals.org
DOI: 10.1161/HYPERTENSIONAHA.113.02217
Downloaded from http://hyper.ahajournals.org/ by guest on February 4, 2014 297
298 Hypertension February 2014 III and investigations were performed in accordance with the principles of the Declaration of Helsinki. Detailed eligibility criteria are given in the online-only Data Supplement. We included 121 healthy white subjects of both sexes (18–75 years), 40 patients with type-2 DM with (n=20, DM+) or without (n=20, DM−) microvascular complications, 41 patients with essential hypertension treated (n=20) or not treated (n=21) with a renin–angiotensin system (RAS) blocker, 9 patients with primary aldosteronism (PA), and 10 patients with Gitelman syndrome (GS). Blood samples for hormone determinations were collected at ≈08:00 am in fasting conditions after 1-hour rest in a semirecumbent position. The influence of circadian cycle, posture, and of ethnicity was also studied in 19 healthy male subjects aged 18 to 35 years (10 white subjects selected from the group of the 121 healthy white subjects and 9 additional black subjects). Blood was sampled in fasting conditions after 1-hour rest in a semirecumbent position at repeated intervals. All subjects were studied on an uncontrolled sodium diet.
Methods Detailed methods are given in the online-only Data Supplement.
Gel Chromatography of Human Plasma and Determination of sPRR in Eluted Fractions
Plasma from 1 healthy subject was separated by gel filtration on an Ultrogel AcA44 (1×45 cm) column (Sigma-Aldrich, St. Louis, MO). sPRR immunoreactivity in each fraction was determined by ELISA (see below).
Plasma sPRR and Hormone Measurements
Plasma sPRR was measured by ELISA (IBL International GmbH, Hamburg, Germany) as described previously.4 Plasma active and total renin, aldosterone, cortisol, follicle-stimulating hormone, luteinizing hormone, and progesterone concentrations were measured using commercially available kits. Plasma prorenin concentration was calculated as (total renin concentration)−(active renin concentration).
Statistical Analysis ANCOVA was used to adjust comparisons after assessment of the effect of the various potential confounders (age, sex, and ethnicity) on plasma sPRR and other biochemical parameters. The assumptions of ANCOVA (homogeneity of variance and normality of the residuals) were checked for each variable and a logarithmic transformation was applied as appropriate. The linear relationship between the dependent and quantitative independent variables was checked graphically in univariate models. First-order interaction terms were systematically tested in multivariate models. ANCOVA was performed only if the assumption of linearity was fulfilled. For the circadian cycle study, repeated measures were analyzed using linear mixed effect models. Data are expressed as medians (interquartile range; normally distributed parameters) or geometric mean with 95% confidence intervals, unless otherwise specified. Differences between groups are given as mean and 95% confidence intervals. SAS software version 9.2 was used for all statistical analyses (SAS Inc Cary, NC). A P
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://hyper.ahajournals.org/content/63/2/297
Data Supplement (unedited) at: http://hyper.ahajournals.org/content/suppl/2013/11/11/HYPERTENSIONAHA.113.02217.DC1.html
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Hypertension can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at: http://www.lww.com/reprints Subscriptions: Information about subscribing to Hypertension is online at: http://hyper.ahajournals.org//subscriptions/
Downloaded from http://hyper.ahajournals.org/ by guest on February 4, 2014
Renin–Angiotensin System Plasma Soluble (Pro)Renin Receptor Is Independent of Plasma Renin, Prorenin, and Aldosterone Concentrations But Is Affected by Ethnicity Geneviève Nguyen,* Anne Blanchard,* Emmanuel Curis, Damien Bergerot, Yann Chambon, Takuo Hirose, Aurore Caumont-Prim, Sylvie Brailly Tabard, Stéphanie Baron, Michael Frank, Kazuhito Totsune, Michel Azizi Abstract—A soluble (pro)renin receptor (sPRR) circulates in plasma and is able to bind renin and prorenin. It is not known whether plasma sPRR concentrations vary with the activity of the renin–angiotensin system. We measured plasma sPRR, renin, prorenin, and aldosterone concentrations in 121 white and 9 black healthy subjects, 40 patients with diabetes mellitus, 41 hypertensive patients with or without renin–angiotensin system blockers, 9 patients with primary aldosteronism, and 10 patients with Gitelman syndrome. Median physiological plasma sPRR concentration was 23.5 ng/mL (interquartile range, 20.9–26.5) under usual uncontrolled sodium diet. sPRR concentration in healthy subjects, unlike renin and prorenin, did not display circadian variation or dependence on age, sex, posture, or hormonal status. sPRR concentrations were ≈25% lower in black than in white subjects, whereas renin concentrations were ≈40% lower. Patients with diabetes mellitus (average renin–high prorenin levels) and with hypertension only (average renin–average prorenin levels) had sPRR concentrations similar to healthy subjects. Renin–angiotensin system blockade was associated with increase of sPRR concentration by ≈12%. sPRR in patients with primary aldosteronism (low renin–low prorenin) and Gitelman syndrome (high renin–high prorenin) were similar and ≈10% higher than in healthy subjects. There was no correlation between sPRR and renin or prorenin. In conclusion, our results show that plasma sPRR concentrations are dependent on ethnicity and independent of renin, prorenin, and aldosterone concentrations in healthy subjects and in patients with contrasted degrees of renin– angiotensin system activity. (Hypertension. 2014;63:297-302.) Online Data Supplement
•
Key Words: diabetes mellitus ◼ ethnology ◼ hyperaldosteronism ◼ hypertension, essential
M
ature active renin and its inactive precursor prorenin bind to the (pro)renin receptor (PRR).1 In addition to triggering intracellular signals, renin and prorenin binding to PRR increases their enzymatic activity.1 A soluble form of PRR (sPRR) is generated by intracellular cleavage by furin and is secreted in plasma.2 sPRR binds renin and prorenin2 and has been reported to activate prorenin.3 sPRR can be measured by ELISA,4 providing new opportunities for investigating the regulation of PRR synthesis and sPRR secretion. Increased PRR expression has been shown in failing hearts5 and sPRR variations have been reported during pregnancy,6,7 in patients with chronic kidney disease8 and with heart failure.9 However, it is not known whether plasma sPRR is influenced by physiological or pathological changes of the renin–angiotensin–aldosterone system (RAAS).
The objectives of our study were (1) to establish reference values for plasma sPRR concentrations in healthy subjects and to identify physiological factors associated with changes in these concentrations; and (2) to determine the relationships among plasma renin, prorenin, aldosterone, and sPRR concentrations in pathological conditions involving contrasted RAAS activation, type-2 diabetes mellitus (DM), essential hypertension, and primary and secondary hyperaldosteronism.
Subjects and Methods Subjects All subjects provided written informed consent to participate in the study. The protocol was approved by the Institutional Review Committee Comité de Protection des Personnes, Paris-Île de France
Received August 10, 2013; first decision August 27, 2013; revision accepted October 14, 2013. From the INSERM, U1050, Paris, France (G.N.); Collège de France, Center for Interdisciplinary Research in Biology, Paris, France (G.N., T.H.); CNRS, UMR 7241, Paris, France (G.N.); Université Paris Descartes, Faculté de Médecine, Sorbonne Paris Cité, Paris, France (A.B., Y.C., S.B., M.F., M.A.); Assistance Publique Hôpitaux de Paris (A.B., D.B., Y.C., S.B., M.F., M.A.) and INSERM, CIC 9201 (A.B., E.C., M.A.), Hôpital Européen Georges Pompidou, Centre d’Investigations Cliniques, Paris, France; Laboratoire de biomathématiques, EA 4466, Faculté de pharmacie, Université Paris Descartes, Sorbonne Paris Cité, Paris, France (E.C.); Department of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Seiryo-machi, Aoba-ku, Sendai, Miyagi, Japan (T.H.); Assistance Publique—Hôpitaux de Paris, Hôpital européen Georges-Pompidou, Unité d’Épidémiologie et de Recherche Clinique, Paris, France (A.C.-P.); INSERM, Centre D’investigation Épidémiologique, Paris, France (A.C.-P.); Assistance Publique Hôpitaux de Paris, Hôpital Kremlin Bicêtre, Laboratoire d’Hormonologie, Le Kremlin-Bicêtre, France (S.B.T.); and Department of Social Welfare, Faculty of Synthetic Welfare, Tohoku Fukushi University, Kunimi, Aoba-ku, Sendai, Japan (K.T.). *These authors contributed equally to this work. The online-only Data Supplement is available with this article at http://hyper.ahajournals.org/lookup/suppl/doi:10.1161/HYPERTENSIONAHA. 113.02217/-/DC1. Correspondence to Genevieve Nguyen, Centre for Interdisciplinary Research in Biology, UMR INSERM U1050/CNRS 7241, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05. E-mail [email protected] © 2013 American Heart Association, Inc. Hypertension is available at http://hyper.ahajournals.org
DOI: 10.1161/HYPERTENSIONAHA.113.02217
Downloaded from http://hyper.ahajournals.org/ by guest on February 4, 2014 297
298 Hypertension February 2014 III and investigations were performed in accordance with the principles of the Declaration of Helsinki. Detailed eligibility criteria are given in the online-only Data Supplement. We included 121 healthy white subjects of both sexes (18–75 years), 40 patients with type-2 DM with (n=20, DM+) or without (n=20, DM−) microvascular complications, 41 patients with essential hypertension treated (n=20) or not treated (n=21) with a renin–angiotensin system (RAS) blocker, 9 patients with primary aldosteronism (PA), and 10 patients with Gitelman syndrome (GS). Blood samples for hormone determinations were collected at ≈08:00 am in fasting conditions after 1-hour rest in a semirecumbent position. The influence of circadian cycle, posture, and of ethnicity was also studied in 19 healthy male subjects aged 18 to 35 years (10 white subjects selected from the group of the 121 healthy white subjects and 9 additional black subjects). Blood was sampled in fasting conditions after 1-hour rest in a semirecumbent position at repeated intervals. All subjects were studied on an uncontrolled sodium diet.
Methods Detailed methods are given in the online-only Data Supplement.
Gel Chromatography of Human Plasma and Determination of sPRR in Eluted Fractions
Plasma from 1 healthy subject was separated by gel filtration on an Ultrogel AcA44 (1×45 cm) column (Sigma-Aldrich, St. Louis, MO). sPRR immunoreactivity in each fraction was determined by ELISA (see below).
Plasma sPRR and Hormone Measurements
Plasma sPRR was measured by ELISA (IBL International GmbH, Hamburg, Germany) as described previously.4 Plasma active and total renin, aldosterone, cortisol, follicle-stimulating hormone, luteinizing hormone, and progesterone concentrations were measured using commercially available kits. Plasma prorenin concentration was calculated as (total renin concentration)−(active renin concentration).
Statistical Analysis ANCOVA was used to adjust comparisons after assessment of the effect of the various potential confounders (age, sex, and ethnicity) on plasma sPRR and other biochemical parameters. The assumptions of ANCOVA (homogeneity of variance and normality of the residuals) were checked for each variable and a logarithmic transformation was applied as appropriate. The linear relationship between the dependent and quantitative independent variables was checked graphically in univariate models. First-order interaction terms were systematically tested in multivariate models. ANCOVA was performed only if the assumption of linearity was fulfilled. For the circadian cycle study, repeated measures were analyzed using linear mixed effect models. Data are expressed as medians (interquartile range; normally distributed parameters) or geometric mean with 95% confidence intervals, unless otherwise specified. Differences between groups are given as mean and 95% confidence intervals. SAS software version 9.2 was used for all statistical analyses (SAS Inc Cary, NC). A P
