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Wiegel RE, Fares DA, Willemsen SP, Steegers EA, Danser AJ, Steegers-Theunissen RP. First-trimester maternal renin-angiotensin-aldosterone system activation and fetal growth and birth weight: The Rotterdam Periconceptional Cohort. Reprod Biomed Online 2022; 44:1110-1122. [DOI: 10.1016/j.rbmo.2021.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
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Barsha G, Walton SL, Kwok E, Mirabito Colafella KM, Pinar AA, Hilliard Krause LM, Gaspari TA, Widdop RE, Samuel CS, Denton KM. Relaxin Attenuates Organ Fibrosis via an Angiotensin Type 2 Receptor Mechanism in Aged Hypertensive Female Rats. KIDNEY360 2021; 2:1781-1792. [PMID: 35373008 PMCID: PMC8785838 DOI: 10.34067/kid.0002722021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 09/07/2021] [Indexed: 02/04/2023]
Abstract
Background The antifibrotic effects of recombinant human relaxin (RLX) in the kidney are dependent on an interaction between its cognate receptor (RXFP1) and the angiotensin type 2 receptor (AT2R) in male models of disease. Whether RLX has therapeutic effects, which are also mediated via AT2R, in hypertensive adult and aged/reproductively senescent females is unknown. Thus, we determined whether treatment with RLX provides cardiorenal protection via an AT2R-dependent mechanism in adult and aged female stroke-prone spontaneously hypertensive rats (SHRSPs). Methods In 6-month-old (6MO) and 15-month-old ([15MO]; reproductively senescent) female SHRSP, systolic BP (SBP), GFR, and proteinuria were measured before and after 4 weeks of treatment with vehicle (Veh), RLX (0.5 mg/kg per day s.c.), or RLX+PD123319 (AT2R antagonist; 3 mg/kg per day s.c.). Aortic endothelium-dependent relaxation and fibrosis of the kidney, heart, and aorta were assessed. Results In 6MO SHRSP, RLX significantly enhanced GFR by approximately 25% (P=0.001) and reduced cardiac fibrosis (P=0.01) as compared with vehicle-treated counterparts. These effects were abolished or blunted by PD123319 coadministration. In 15MO females, RLX reduced interstitial renal (P=0.02) and aortic (P=0.003) fibrosis and lowered SBP (13±3 mm Hg; P=0.04) relative to controls. These effects were also blocked by PD123319 cotreatment (all P=0.05 versus RLX treatment alone). RLX also markedly improved vascular function by approximately 40% (P<0.001) in 15MO SHRSP, but this was not modulated by PD123319 cotreatment. Conclusions The antifibrotic and organ-protective effects of RLX, when administered to a severe model of hypertension, conferred cardiorenal protection in adult and reproductively senescent female rats to a great extent via an AT2R-mediated mechanism.
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Affiliation(s)
- Giannie Barsha
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Sarah L. Walton
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Edmund Kwok
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Katrina M. Mirabito Colafella
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Anita A. Pinar
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Pharmacology, Monash University, Melbourne, Victoria, Australia
| | - Lucinda M. Hilliard Krause
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Tracey A. Gaspari
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Pharmacology, Monash University, Melbourne, Victoria, Australia
| | - Robert E. Widdop
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Pharmacology, Monash University, Melbourne, Victoria, Australia
| | - Chrishan S. Samuel
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Pharmacology, Monash University, Melbourne, Victoria, Australia
| | - Kate M. Denton
- Cardiovascular Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia,Department of Physiology, Monash University, Melbourne, Victoria, Australia
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Ahmed S, Layton AT. Sex-specific computational models for blood pressure regulation in the rat. Am J Physiol Renal Physiol 2020; 318:F888-F900. [PMID: 32036698 DOI: 10.1152/ajprenal.00376.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In the past decades, substantial effort has been devoted to the development of computational models of the cardiovascular system. Some of these models simulate blood pressure regulation in humans and include components of the circulatory, renal, and neurohormonal systems. Although such human models are intended to have clinical value in that they can be used to assess the effects and reveal mechanisms of hypertensive therapeutic treatments, rodent models would be more useful in assisting the interpretation of animal experiments. Also, despite well-known sexual dimorphism in blood pressure regulation, almost all published models are gender neutral. Given these observations, the goal of this project is to develop the first computational models of blood pressure regulation for male and female rats. The resulting sex-specific models represent the interplay among cardiovascular function, renal hemodynamics, and kidney function in the rat; they also include the actions of the renal sympathetic nerve activity and the renin-angiotensin-aldosterone system as well as physiological sex differences. We explore mechanisms responsible for blood pressure and renal autoregulation and notable sexual dimorphism. Model simulations suggest that fluid and sodium handling in the kidney of female rats, which differs significantly from males, may contribute to their observed lower salt sensitivity as compared with males. Additionally, model simulations highlight sodium handling in the kidney and renal sympathetic nerve activity sensitivity as key players in the increased resistance of females to angiotensin II-induced hypertension as compared with males.
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Affiliation(s)
- Sameed Ahmed
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Anita T Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada.,Department of Biology and Schools of Computer Science and Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
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Gupta S, Pepper RJ, Ashman N, Walsh SB. Nephrotic Syndrome: Oedema Formation and Its Treatment With Diuretics. Front Physiol 2019; 9:1868. [PMID: 30697163 PMCID: PMC6341062 DOI: 10.3389/fphys.2018.01868] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/11/2018] [Indexed: 01/01/2023] Open
Abstract
Oedema is a defining element of the nephrotic syndrome. Its' management varies considerably between clinicians, with no national or international clinical guidelines, and hence variable outcomes. Oedema may have serious sequelae such as immobility, skin breakdown and local or systemic infection. Treatment of nephrotic oedema is often of limited efficacy, with frequent side-effects and interactions with other pharmacotherapy. Here, we describe the current paradigms of oedema in nephrosis, including insights into emerging mechanisms such as the role of the abnormal activation of the epithelial sodium channel in the collecting duct. We then discuss the physiological basis for traditional and novel therapies for the treatment of nephrotic oedema. Despite being the cardinal symptom of nephrosis, few clinical studies guide clinicians to the rational use of therapy. This is reflected in the scarcity of publications in this field; it is time to undertake new clinical trials to direct clinical practice.
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Affiliation(s)
- Sanjana Gupta
- UCL Centre for Nephrology, University College London, London, United Kingdom.,Renal Unit, The Royal London Hospital, Bart's Health NHS Trust, London, United Kingdom
| | - Ruth J Pepper
- UCL Centre for Nephrology, University College London, London, United Kingdom
| | - Neil Ashman
- Renal Unit, The Royal London Hospital, Bart's Health NHS Trust, London, United Kingdom
| | - Stephen B Walsh
- UCL Centre for Nephrology, University College London, London, United Kingdom
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Deng A, Conrad K, Baylis C. Relaxin-mediated renal vasodilation in the rat is associated with falls in glomerular blood pressure. Am J Physiol Regul Integr Comp Physiol 2018; 314:R147-R152. [PMID: 29046312 PMCID: PMC5867670 DOI: 10.1152/ajpregu.00148.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 09/25/2017] [Accepted: 10/06/2017] [Indexed: 11/22/2022]
Abstract
Relaxin (RLX) is a pleiotropic peptide hormone with marked renal vasodilatory actions that are physiologically important during pregnancy. RLX also has potent antifibrotic actions and is being tested therapeutically in various fibrotic diseases, including chronic kidney disease (CKD). Since renal vasodilation may expose the glomerulus to increased blood pressure [glomerular capillary pressure (PGC)], which exacerbates progression of CKD, we assessed the glomerular hemodynamic actions of acute (0.89 µg·100 g body wt-1·h-1 iv over 75 min) and chronic (1.5 µg·100 g body wt-1·h-1 sc) administration of RLX. Both acute and chronic RLX produced marked renal vasodilation and increased renal plasma flow (RPF) in euvolemic, anesthetized male rats. Glomerular filtration rate also increased with RLX, but the magnitude of the rise was much less than the increase in RPF due to concomitant decreases in filtration fraction. The fall in filtration fraction was the result of significant decreases in PGC, despite a slight increase in mean arterial blood pressure (MAP) with acute RLX and no net change in MAP with chronic RLX. This fall in PGC occurred because of the "in-series" arrangement of the afferent and efferent arteriolar resistance vessels, which can regulate PGC independently of MAP. With both acute and chronic RLX, efferent arteriolar resistance vessels relaxed to a greater extent than afferent arteriolar resistance vessels, thus producing falls in PGC. Based on this finding, RLX has a beneficial hemodynamic impact on the kidney, which, together with the antifibrotic actions of RLX, suggests a strong therapeutic potential for use in CKD.
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Affiliation(s)
- Aihua Deng
- Departments of Physiology and Functional Genomics, University of Florida , Gainesville, Florida
| | - Kirk Conrad
- Departments of Obstetrics and Gynecology, University of Florida , Gainesville, Florida
- Department of Medicine, University of Florida , Gainesville, Florida
| | - Chris Baylis
- Departments of Obstetrics and Gynecology, University of Florida , Gainesville, Florida
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Shao W, Rosales CB, Gonzalez C, Prieto MC, Navar LG. Effects of serelaxin on renal microcirculation in rats under control and high-angiotensin environments. Am J Physiol Renal Physiol 2018; 314:F70-F80. [PMID: 28978531 DOI: 10.1152/ajprenal.00201.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serelaxin is a novel recombinant human relaxin-2 that has been investigated for the treatment of acute heart failure. However, its effects on renal function, especially on the renal microcirculation, remain incompletely characterized. Our immunoexpression studies localized RXFP1 receptors on vascular smooth muscle cells and endothelial cells of afferent arterioles and on principal cells of collecting ducts. Clearance experiments were performed in male and female normotensive rats and Ang II-infused male rats. Serelaxin increased mean arterial pressure slightly and significantly increased renal blood flow, urine flow, and sodium excretion rate. Group analysis of all serelaxin infusion experiments showed significant increases in GFR. During infusion with subthreshold levels of Ang II, serelaxin did not alter mean arterial pressure, renal blood flow, GFR, urine flow, or sodium excretion rate. Heart rates were elevated during serelaxin infusion alone (37 ± 5%) and in Ang II-infused rats (14 ± 2%). In studies using the in vitro isolated juxtamedullary nephron preparation, superfusion with serelaxin alone (40 ng/ml) significantly dilated afferent arterioles (10.8 ± 1.2 vs. 13.5 ± 1.1 µm) and efferent arterioles (9.9 ± 0.9 vs. 11.9 ± 1.0 µm). During Ang II superfusion, serelaxin did not alter afferent or efferent arteriolar diameters. During NO synthase inhibition (l-NNA), afferent arterioles also did not show any vasodilation during serelaxin infusion. In conclusion, serelaxin increased overall renal blood flow, urine flow, GFR, and sodium excretion and dilated the afferent and efferent arterioles in control conditions, but these effects were attenuated or prevented in the presence of exogenous Ang II and NO synthase inhibitors.
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Affiliation(s)
- Weijian Shao
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine , New Orleans, Louisiana
| | - Carla B Rosales
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine , New Orleans, Louisiana
| | - Camila Gonzalez
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine , New Orleans, Louisiana
| | - Minolfa C Prieto
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine , New Orleans, Louisiana
| | - L Gabriel Navar
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine , New Orleans, Louisiana
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Wang D, Luo Y, Myakala K, Orlicky DJ, Dobrinskikh E, Wang X, Levi M. Serelaxin improves cardiac and renal function in DOCA-salt hypertensive rats. Sci Rep 2017; 7:9793. [PMID: 28851937 PMCID: PMC5574886 DOI: 10.1038/s41598-017-09470-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/26/2017] [Indexed: 11/09/2022] Open
Abstract
Serelaxin, a recombinant form of the naturally occurring peptide hormone relaxin-2, is a pleiotropic vasodilating hormone that has been studied in patients with acute heart failure. In this study, the effects of serelaxin on cardiac and renal function, fibrosis, inflammation and lipid accumulation were studied in DOCA-salt treated rats. Uninephrectomized rats were assigned to two groups: controls provided with normal drinking water and DOCA provided with DOCA pellets and sodium chloride drinking water. After 4 weeks, the DOCA-salt rats were randomly selected and implanted with osmotic minipumps delivering vehicle or serelaxin for another 4 weeks. Treatment with serelaxin prevented cardiac and renal dysfunction in DOCA-salt rats. Serelaxin prevented cardiac and renal fibrosis, as determined by Picrosirius Red staining and Second Harmonic Generation (SHG) Microscopy. Treatment of DOCA-salt rats with serelaxin decreased renal inflammation, including the expression of TGF-β, NFκB, MCP-1, IL-1, IL-6, ICAM-1, VCAM-1 and CD68 macrophages. Serelaxin also decreased lipid accumulation in kidney in part by decreasing SREBP-1c, SREBP-2, ChREBP, FATP1, HMGCoAR, and LDL receptor, and increasing Acox1 and ABCA1. In summary, serelaxin reversed DOCA-salt induced cardiac and renal dysfunction.
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Affiliation(s)
- Dong Wang
- Renal Diseases and Hypertension, School of Medicine, University of Colorado ANSCHUTZ MEDICAL CAMPUS, Aurora, Colorado, 80045, USA
| | - Yuhuan Luo
- Renal Diseases and Hypertension, School of Medicine, University of Colorado ANSCHUTZ MEDICAL CAMPUS, Aurora, Colorado, 80045, USA
| | - Komuraiah Myakala
- Renal Diseases and Hypertension, School of Medicine, University of Colorado ANSCHUTZ MEDICAL CAMPUS, Aurora, Colorado, 80045, USA
| | - David J Orlicky
- Department of Pathology, School of Medicine, University of Colorado ANSCHUTZ MEDICAL CAMPUS, Aurora, Colorado, 80045, USA
| | - Evgenia Dobrinskikh
- Renal Diseases and Hypertension, School of Medicine, University of Colorado ANSCHUTZ MEDICAL CAMPUS, Aurora, Colorado, 80045, USA
| | - Xiaoxin Wang
- Renal Diseases and Hypertension, School of Medicine, University of Colorado ANSCHUTZ MEDICAL CAMPUS, Aurora, Colorado, 80045, USA
| | - Moshe Levi
- Renal Diseases and Hypertension, School of Medicine, University of Colorado ANSCHUTZ MEDICAL CAMPUS, Aurora, Colorado, 80045, USA.
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Conrad KP. G-Protein-coupled receptors as potential drug candidates in preeclampsia: targeting the relaxin/insulin-like family peptide receptor 1 for treatment and prevention. Hum Reprod Update 2016; 22:647-64. [PMID: 27385360 DOI: 10.1093/humupd/dmw021] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/16/2016] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Important roles for G-protein-coupled receptors (GPCRs) have been identified in the maternal physiological adaptations to pregnancy and in the pathogenesis of preeclampsia. On this basis, GPCRs are potential therapeutic targets for preeclampsia. OBJECTIVES AND RATIONALE In this review, vasopressin and apelin are initially considered in this context before the focus on the hormone relaxin and its cognate receptor, the relaxin/insulin-like family peptide receptor 1 (RXFP1). Based on both compelling scientific rationale and a promising safety profile, the relaxin ligand-receptor system is comprehensively evaluated as a potential therapeutic endpoint in preeclampsia. SEARCH METHODS The published literature relating to the topic was searched through January 2016 using PubMed. OUTCOMES Relaxin is a peptide hormone secreted by the corpus luteum; it circulates in the luteal phase and during pregnancy. Activation of RXFP1 is vasodilatory; thus, relaxin supplementation is expected to at least partly restore the fundamental vasodilatory changes of normal pregnancy, thereby alleviating maternal organ hypoperfusion, which is a major pathogenic manifestation of severe preeclampsia. Specifically, by exploiting its pleiotropic hemodynamic attributes in preeclampsia, relaxin administration is predicted to (i) reverse robust arterial myogenic constriction; (ii) blunt systemic and renal vasoconstriction in response to activation of the angiotensin II receptor, type 1; (iii) mollify the action of endogenous vasoconstrictors on uterine spiral arteries with failed remodeling and retained smooth muscle; (iv) increase arterial compliance; (v) enhance insulin-mediated glucose disposal by promoting skeletal muscle vasodilation and (vi) mobilize and activate bone marrow-derived angiogenic progenitor cells, thereby repairing injured endothelium and improving maternal vascularity in organs such as breast, uterus, pancreas, skin and fat. By exploiting its pleiotropic molecular attributes in preeclampsia, relaxin supplementation is expected to (i) enhance endothelial nitric oxide synthesis and bioactivity, as well as directly reduce vascular smooth muscle cytosolic calcium, thus promoting vasodilation; (ii) improve the local angiogenic balance by augmenting arterial vascular endothelial and placental growth factor (VEGF and PLGF) activities; (iii) ameliorate vascular inflammation; (iv) enhance placental peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PCG1α) expression, and hence, peroxisome proliferator-activated receptor gamma (PPAR-γ) activity and (v) confer cytotrophoblast and endothelial cytoprotection. Insofar as impaired endometrial maturation (decidualization) predisposes to the development of preeclampsia, relaxin administration in the late secretory phase and during early pregnancy would be anticipated to improve decidualization, and hence trophoblast invasion and spiral artery remodeling, thereby reducing the risk of preeclampsia. Relaxin has a favorable safety profile both in the non-pregnant condition and during pregnancy. WIDER IMPLICATIONS There is a strong scientific rationale for RXFP1 activation in severe preeclampsia by administration of relaxin, relaxin analogs or small molecule mimetics, in order to mollify the disease pathogenesis for safe prolongation of pregnancy, thus allowing time for more complete fetal maturation, which is a primary therapeutic endpoint in treating the disease. In light of recent data implicating deficient or defective decidualization as a potential etiological factor in preeclampsia and the capacity of relaxin to promote endometrial maturation, the prophylactic application of relaxin to reduce the risk of preeclampsia is a plausible therapeutic approach to consider. Finally, given its pleiotropic and beneficial attributes particularly in the cardiovascular system, relaxin, although traditionally considered as a 'pregnancy' hormone, is likely to prove salutary for several disease indications in the non-pregnant population.
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Affiliation(s)
- Kirk P Conrad
- Department of Physiology and Functional Genomics and Department of Obstetrics and Gynecology, D.H. Barron Reproductive and Perinatal Biology Research Program, University of Florida, 1600 SW Archer Road, PO Box 100274 M522, Gainesville, FL 32610, USA
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10
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Liu LCY, Voors AA, Teerlink JR, Cotter G, Davison BA, Felker GM, Filippatos G, Chen Y, Greenberg BH, Ponikowski P, Pang PS, Prescott MF, Hua TA, Severin TM, Metra M. Effects of serelaxin in acute heart failure patients with renal impairment: results from RELAX-AHF. Clin Res Cardiol 2016; 105:727-37. [PMID: 27017514 PMCID: PMC4988995 DOI: 10.1007/s00392-016-0979-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 03/14/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Serelaxin showed beneficial effects on clinical outcome and trajectories of renal markers in patients with acute heart failure. We aimed to study the interaction between renal function and the treatment effect of serelaxin. METHODS In the current post hoc analysis of the RELAX-AHF trial, we included all patients with available estimated glomerular filtration rate (eGFR) at baseline (n = 1132). Renal impairment was defined as an eGFR <60 ml/min/1.73 m(2) estimated by creatinine. RESULTS 817 (72.2 %) patients had a baseline eGFR <60 ml/min/1.73 m(2). In placebo-treated patients, baseline renal impairment was related to a higher 180 day cardiovascular (HR 3.12, 95 % CI 1.33-7.30) and all-cause mortality (HR 2.81, 95 % CI 1.34-5.89). However, in serelaxin-treated patients, the risk of cardiovascular and all-cause mortality was less pronounced (HR 1.19, 95 % CI 0.54 -2.64; p for interaction = 0.106, and HR 1.15 95 % CI 0.56-2.34 respectively; p for interaction = 0.088). In patients with renal impairment, treatment with serelaxin resulted in a more pronounced all-cause mortality reduction (HR 0.53, 95 % CI 0.34-0.83), compared with patients without renal impairment (HR 1.30, 95 % CI 0.51-3.29). CONCLUSION Renal dysfunction was associated with higher cardiovascular and all-cause mortality in placebo-treated patients, but not in serelaxin-treated patients. The observed reduction in (cardiovascular) mortality in RELAX-AHF was more pronounced in patients with renal dysfunction. These observations need to be confirmed in the ongoing RELAX-AHF-2 trial.
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Affiliation(s)
- Licette C Y Liu
- Department of Cardiology, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Adriaan A Voors
- Department of Cardiology, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
| | - John R Teerlink
- San Francisco Veterans Affairs Medical Center, University of California, San Francisco, CA, USA
| | | | | | - G Michael Felker
- Duke University School of Medicine, Duke Heart Center, Durham, NC, USA
| | - Gerasimos Filippatos
- School of Medicine, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Yakuan Chen
- Columbia University Medical Center, New York, NY, USA
| | | | | | - Peter S Pang
- Indiana University School of Medicine, Indianapolis, IN, USA
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Díez J, Ruilope LM. Serelaxin for the treatment of acute heart failure: a review with a focus on end-organ protection. EUROPEAN HEART JOURNAL. CARDIOVASCULAR PHARMACOTHERAPY 2015; 2:119-30. [PMID: 27418970 PMCID: PMC4853824 DOI: 10.1093/ehjcvp/pvv046] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/26/2015] [Indexed: 12/15/2022]
Abstract
Acute heart failure (AHF) is a complex clinical syndrome characterized by fluid overload and haemodynamic abnormalities (short-term clinical consequences) and the development of end-organ damage (long-term consequences). Current therapies for the treatment of AHF, such as loop diuretics and vasodilators, help to relieve haemodynamic imbalance and congestion, but have not been shown to prevent (and may even contribute to) end-organ damage, or to provide long-term clinical benefit. Serelaxin is the recombinant form of human relaxin-2, a naturally occurring hormone involved in mediating haemodynamic changes during pregnancy. Preclinical and clinical studies have investigated the effects mediated by serelaxin and the suitability of this agent for the treatment of patients with AHF. Data suggest that serelaxin acts via multiple pathways to improve haemodynamics at the vascular, cardiac, and renal level and provide effective congestion relief. In addition, this novel agent may protect the heart, kidneys, and liver from damage by inhibiting inflammation, oxidative stress, cell death, and tissue fibrosis, and stimulating angiogenesis. Serelaxin may therefore improve both short- and long-term outcomes in patients with AHF. In this review, we examine the unique mechanisms underlying the potential benefits of serelaxin for the treatment of AHF, in particular, those involved in mediating end-organ protection.
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Affiliation(s)
- Javier Díez
- Program of Cardiovascular Diseases, Centre for Applied Medical Research and Department of Cardiology and Cardiac Surgery, University of Navarra Clinic, University of Navarra, Av. Pío XII 55, Pamplona 31008, Spain
| | - Luis M Ruilope
- Research Institute, Hypertension Unit, Hospital 12 de Octubre and Department of Public Health and Preventive Medicine, University Autónoma, Madrid, Spain
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Halls ML, Bathgate RAD, Sutton SW, Dschietzig TB, Summers RJ. International Union of Basic and Clinical Pharmacology. XCV. Recent advances in the understanding of the pharmacology and biological roles of relaxin family peptide receptors 1-4, the receptors for relaxin family peptides. Pharmacol Rev 2015; 67:389-440. [PMID: 25761609 DOI: 10.1124/pr.114.009472] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1-4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gα(s), Gα(i), and Gα(o) proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gα(s)- and Gα(o)-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gα(i)/Gα(o) proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1-4, the challenges facing the field, and current prospects for new therapeutics.
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Affiliation(s)
- Michelle L Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Ross A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Steve W Sutton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Thomas B Dschietzig
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
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Wilson SS, Ayaz SI, Levy PD. Relaxin: A Novel Agent for the Treatment of Acute Heart Failure. Pharmacotherapy 2015; 35:315-27. [DOI: 10.1002/phar.1548] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Suprat S. Wilson
- Department of Pharmacy; Detroit Receiving Hospital; Detroit Michigan
| | - Syed I. Ayaz
- Department of Emergency Medicine; Wayne State University School of Medicine; Detroit Michigan
| | - Phillip D. Levy
- Department of Emergency Medicine; Cardiovascular Research Institute; Wayne State University School of Medicine; Detroit Michigan
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Dschietzig TB. Recombinant human relaxin-2: (how) can a pregnancy hormone save lives in acute heart failure? Am J Cardiovasc Drugs 2014; 14:343-55. [PMID: 24934696 DOI: 10.1007/s40256-014-0078-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Acute heart failure (AHF) syndrome, characterized by pulmonary and/or venous congestion owing to increased cardiac filling pressures with or without diminished cardiac output, is still associated with high post-discharge mortality and hospitalization rates. Many novel and promising therapeutic approaches, among them endothelin-1, vasopressin and adenosine antagonists, calcium sensitization, and recombinant B-type natriuretic hormone, have failed in large studies. Likewise, the classic drugs, vasodilators, diuretics, and inotropes, have never been shown to lower mortality.The phase III trial RELAX-AHF tested recombinant human relaxin-2 (rhRlx) and found it to improve clinical symptoms moderately, to be neutral regarding the combination of death and hospitalization at day 60, to be safe, and to lower mortality at day 180. This review focuses on basic research and pre-clinical findings that may account for the benefit of rhRlx in AHF. The drug combines short-term hemodynamic advantages, such as moderate blood pressure decline and functional endothelin-1 antagonism, with a wealth of protective effects harboring long-term benefits, such as anti-inflammatory, anti-fibrotic, and anti-oxidative actions. These pleiotropic effects are exerted through a complex and intricate signaling cascade involving the relaxin-family peptide receptor-1, the glucocorticoid receptor, nitric oxide, and a cell type-dependent variety of kinases and transcription factors.
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Sasser JM. The emerging role of relaxin as a novel therapeutic pathway in the treatment of chronic kidney disease. Am J Physiol Regul Integr Comp Physiol 2013; 305:R559-65. [PMID: 23883673 DOI: 10.1152/ajpregu.00528.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Emerging evidence supports a potential therapeutic role of relaxin in fibrotic diseases, including chronic kidney disease. Relaxin is a pleiotropic hormone, best characterized for its role in the reproductive system; however, recent studies have demonstrated a role of relaxin in the cardiorenal system. Both relaxin and its receptor, RXFP1, are expressed in the kidney, and relaxin has been shown to play a role in renal vasodilation, in sodium excretion, and as an antifibrotic agent. Together, these findings suggest that the kidney is a target organ of relaxin. Therefore, the purpose of this review is to describe the functional and structural impacts of relaxin treatment on the kidney and to discuss evidence that relaxin prevents disease progression in several experimental models of kidney disease. In addition, this review will present potential mechanisms that are involved in the therapeutic actions of relaxin.
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Affiliation(s)
- Jennifer M Sasser
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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Cernaro V, Lacquaniti A, Lupica R, Buemi A, Trimboli D, Giorgianni G, Bolignano D, Buemi M. Relaxin: new pathophysiological aspects and pharmacological perspectives for an old protein. Med Res Rev 2013; 34:77-105. [PMID: 23401142 DOI: 10.1002/med.21277] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Human relaxin-2 (hereafter simply defined as "relaxin") is a 6-kDa peptidic hormone best known for the physiological role played during pregnancy in the growth and differentiation of the reproductive tract and in the renal and systemic hemodynamic changes. This factor can also be involved in the pathophysiology of arterial hypertension and heart failure, in the molecular pathways of fibrosis and cancer, and in angiogenesis and bone remodeling. It belongs to the relaxin peptide family, whose members comprehensively exert numerous effects through interaction with different types of receptors, classified as relaxin family peptide (RXFP) receptors (RXFP1, RXFP2, RXFP3, RXFP4). Research looks toward the in-depth examination and complete understanding of relaxin in its various pleiotropic actions. The intent is to evaluate the likelihood of employing this substance for therapeutic purposes, for instance in diseases where a deficit could be part of the underlying pathophysiological mechanisms, also avoiding any adverse effect. Relaxin is already being considered as a promising drug, especially in acute heart failure. A careful study of the different RXFPs and their receptors and the comprehension of all biological activities of these hormones will probably provide new drugs with a potential wide range of therapeutic applications in the near future.
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Affiliation(s)
- Valeria Cernaro
- Department of Internal Medicine, University of Messina, Via Consolare Valeria, 1, 98100, Italy
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Baltatu OC, Iliescu R, Zaugg CE, Reckelhoff JF, Louie P, Schumacher C, Campos LA. Antidiuretic effects of the endothelin receptor antagonist avosentan. Front Physiol 2012; 3:103. [PMID: 22529820 PMCID: PMC3328756 DOI: 10.3389/fphys.2012.00103] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 04/02/2012] [Indexed: 01/08/2023] Open
Abstract
Several clinical studies have investigated the potential benefits of endothelin receptor antagonism in chronic pathologies such as diabetic kidney disease. However, fluid retention and edema have been identified as major side effects of endothelin receptor antagonists. In the present study we hypothesized that avosentan which was described as a predominant ETA receptor antagonist would produce fluid retention at high concentrations where non-specific blockade of ETB receptors may occur. Incremental doses of the predominant ETA receptor antagonist SPP301 (0.003; 0.03; 3 mg/kg) were administered intravenously to anesthetized Sprague-Dawley rats undergoing saline diuresis. Diuresis, glomerular filtration rate, and blood pressure (BP) were monitored. SPP301 decreased urine output (5.6; 34.8; 58.8% decrease from vehicle) and fractional excretion of water (5.7; 31.7; 56.4% decrease from vehicle) in a concentration-dependent manner. Glomerular filtration rate was unchanged while BP was reduced by 10 mmHg only by the highest dose of SPP301. Administration of the ETB selective receptor antagonist BQ-788 (3 mg/kg) following SPP301 3 mg/kg did not further decrease urine output or water excretion and was without effect on glomerular filtration rate. These data indicate that increasing concentrations of SPP301 may also block ETB receptors and cause antidiuresis. This effect could explain why fluid retention and edema occur during treatment with predominant ETA receptor blockers.
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Abstract
Relaxin, a naturally-occurring hormone in the insulin family, was discovered to have a physiologic role in pregnancy. Named initially for its relaxing effect on the pubic ligament, relaxin receptors have since been found to be widely distributed in many organs in both males and females. Acting through multiple pathways, including the stimulation of gelatinases leading to activation of endothelin type B receptors and subsequently nitric oxide, relaxin has been shown to cause vasodilation. In animal models and studies in humans, relaxin has been shown to increase cardiac output and renal perfusion. Due to these effects, relaxin has been examined as a treatment for acute heart failure. The results of phase I and II trials have shown favorable clinical trends without any major adverse events, suggesting that relaxin has the potential to be an effective medication for acute heart failure in conjunction with or in place of current treatments.
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Abstract
Relaxin is an approximately 6-kilodalton peptide hormone secreted by the corpus luteum, and circulates in the maternal blood during pregnancy. Relaxin administration to awake, chronically instrumented, nonpregnant rats mimics the vasodilatory phenomena of pregnancy. Furthermore, immunoneutralization of relaxin or its elimination from the circulation during midterm pregnancy in awake rats prevents maternal systemic and renal vasodilation, and the increase in global arterial compliance. Human investigation, albeit limited through 2010, also reveals vasodilatory effects of relaxin in the nonpregnant condition and observations consistent with a role for relaxin in gestational renal hyperfiltration. Evidence suggests that the vasodilatory responses of relaxin are mediated by its major receptor, the relaxin/insulin-like family peptide 1 receptor, RFXP1. The molecular mechanisms of relaxin vasodilation depend on the duration of hormone exposure (ie, there are rapid and sustained vasodilatory responses). Newly emerging data support the role of Gα(i/o) protein coupling to phosphatidylinositol-3 kinase/Akt (protein kinase B)-dependent phosphorylation and activation of endothelial nitric oxide synthase in the rapid vasodilatory responses of relaxin. Sustained vasodilatory responses critically depend on vascular endothelial and placental growth factors, and increases in arterial gelatinase(s) activity. Gelatinases hydrolyze big endothelin (ET) at a gly-leu bond to form ET(1-32), which activates the endothelial ET(B)/nitric oxide vasodilatory pathway. Although the relevance of relaxin biology to preeclampsia is largely speculative at this time, there are potential tantalizing links that are discussed in the context of our current understanding of the etiology and pathophysiology of the disease.
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Affiliation(s)
- Kirk P Conrad
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1600 SW Archer Road, Gainesville, FL 32610, USA.
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Abstract
Relaxin is a naturally occurring human peptide initially identified as a reproductive hormone. More recently, relaxin has been shown to play a key role in the maternal hemodynamic and renal adjustments that accommodate pregnancy. An understanding of these physiologic effects has led to the evaluation of relaxin as a pharmacologic agent for the treatment of patients with acute heart failure. Preliminary results have been encouraging. In addition, the other known biologic properties of relaxin, including anti-inflammatory effects, extracellular matrix remodeling effects, and angiogenic and anti-ischemic effects, all may play a role in potential benefits of relaxin therapy. Ongoing, large-scale clinical testing will provide additional insights into the potential role of relaxin in the treatment of heart failure.
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Affiliation(s)
- Sam L. Teichman
- Corthera, Inc, a subsidiary of Novartis Pharmaceuticals Corp., 1660 South Amphlett Boulevard, Suite 200, San Mateo, CA 94402 USA
| | - Elaine Unemori
- Corthera, Inc, a subsidiary of Novartis Pharmaceuticals Corp., 1660 South Amphlett Boulevard, Suite 200, San Mateo, CA 94402 USA
| | - John R. Teerlink
- Section of Cardiology, Veterans Affairs Medical Center, University of California, San Francisco VA Medical Center, Cardiology-111C, Building 203, Room 2A-49, 4150 Clement Street, San Francisco, CA 94121-1545 USA
| | - Gad Cotter
- Momentum Research, Inc, 3100 Tower Boulevard, Suite 802, Durham, NC 27707 USA
| | - Marco Metra
- Section of Cardiovascular Diseases, Department of Experimental and Applied Medicine, University of Brescia, Cardiology, University and Civil Hospital, Piazza Spedali Civili 1, 25123 Brescia, Italy
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Bogzil AH, Ashton N. Relaxin-induced changes in renal function and RXFP1 receptor expression in the female rat. Ann N Y Acad Sci 2009; 1160:313-6. [PMID: 19416210 DOI: 10.1111/j.1749-6632.2008.03797.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Relaxin causes renal hyperfiltration, natriuresis, and diuresis in male rats. This study determined the effect of recombinant human relaxin (rhRLX) on renal function in the female rat. After 7 days of rhRLX treatment (0.4 microg/h) urinary excretion of sodium and chloride were significantly lower in the rhRLX-treated group, but urine flow rate was not different from that in controls. Quantitative PCR showed that the RXFP1 receptor was expressed in both the renal cortex and medulla; immuno-localization revealed expression in the proximal tubule and inner medullary collecting ducts. These data show that relaxin elicits pregnancy-like changes in renal function in the female rat.
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Affiliation(s)
- Alsadek H Bogzil
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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22
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Receptor-induced dilatation in the systemic and intrarenal adaptation to pregnancy in rats. PLoS One 2009; 4:e4845. [PMID: 19287481 PMCID: PMC2653634 DOI: 10.1371/journal.pone.0004845] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 02/05/2009] [Indexed: 11/19/2022] Open
Abstract
Normal pregnancy is associated with systemic and intrarenal vasodilatation resulting in an increased glomerular filtration rate. This adaptive response occurs in spite of elevated circulating levels of angiotensin II (Ang II). In the present study, we evaluated the potential mechanisms responsible for this adaptation. The reactivity of the mesangial cells (MCs) cultured from 14-day-pregnant rats to Ang II was measured through changes in the intracellular calcium concentration ([Cai]). The expression levels of inducible nitric oxide synthase (iNOS), the Ang II-induced vasodilatation receptor AT2, and the relaxin (LGR7) receptor were evaluated in cultured MCs and in the aorta, renal artery and kidney cortex by real time-PCR. The intrarenal distribution of LGR7 was further analyzed by immunohistochemistry. The MCs displayed a relative insensitivity to Ang II, which was paralleled by an impressive increase in the expression level of iNOS, AT2 and LGR7. These results suggest that the MCs also adapt to the pregnancy, thereby contributing to the maintenance of the glomerular surface area even in the presence of high levels of Ang II. The mRNA expression levels of AT2 and LGR7 also increased in the aorta, renal artery and kidney of the pregnant animals, whereas the expression of the AT1 did not significantly change. This further suggests a role of these vasodilatation-induced receptors in the systemic and intrarenal adaptation during pregnancy. LGR7 was localized in the glomeruli and on the apical membrane of the tubular cells, with stronger labeling in the kidneys of pregnant rats. These results suggest a role of iNOS, AT2, and LGR7 in the systemic vasodilatation and intrarenal adaptation to pregnancy and also suggest a pivotal role for relaxin in the tubular function during gestation.
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Smith MC, Danielson LA, Conrad KP, Davison JM. Influence of recombinant human relaxin on renal hemodynamics in healthy volunteers. J Am Soc Nephrol 2006; 17:3192-7. [PMID: 17035617 DOI: 10.1681/asn.2005090950] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Maternal renal hemodynamic adaptation to human pregnancy is one of the most dramatic of all physiologic changes, but the factors that are responsible have remained elusive. In rat pregnancy, there are comparable renal hemodynamic changes, and in this species there is comprehensive evidence that the ovarian hormone relaxin (RLX) is responsible. This study investigated the renal effects of recombinant human RLX (rhRLX) in humans. Eleven volunteers (six male, five female) received intravenous infusions of rhRLX over 5 h at an infusion rate that was chosen to sustain serum concentrations that are comparable to early pregnancy. The renal clearances of inulin and para-aminohippurate were used to measure GFR and renal plasma flow, respectively. Irrespective of gender, renal plasma flow was increased by 47% compared with baseline levels (P < 0.0001), but no significant change was observed in GFR. There were no side effects or adverse reactions of rhRLX given as an intravenous infusion, and the data suggest that RLX indeed may be one of the elusive renal vasodilatory factors in human pregnancy. Further work is necessary to elucidate the complimentary factors that permit the concomitant increase in GFR during pregnancy.
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Affiliation(s)
- Marie C Smith
- School of Surgical and Reproductive Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
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