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Alsadery HA, Bamalan OA, Aljubran HJ, Albaish LJ, Al Ghanim BZ. Non-obstetric Acute Abdomen in Pregnancy: a Review of Literature. Med Arch 2023; 77:293-298. [PMID: 37876566 PMCID: PMC10591244 DOI: 10.5455/medarh.2023.77.293-298] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 07/24/2023] [Indexed: 10/26/2023] Open
Abstract
Background Acute abdomen in pregnancy (AAP) is defined as intensive abdominal pain lasting less than 24 hours that may require urgent surgery. It is a challenging situation to diagnose and manage, as it is associated with pain due to the normal anatomical and physiological changes that occur during pregnancy. Objective Therefore, understanding these changes and their effect on almost every system, will help us appreciate the upcoming causes of AAP, mainly the non-obstetric surgical emergencies (e.g., appendicitis, cholecystitis). Methods This article highlights the importance of the well-rounded care that should be offered to every pregnant patient presenting to any center with a Non-obstetric Acute Abdomen. The causes are discussed separately (for surgical pearls), laparoscopic approach and radiologic modality decision-making in pregnancy, which is an academic and a practice-based helpful summary. Results and Discussion This article highlights the importance of the well-rounded care that should be offered to every pregnant patient presenting to any center with a Non-obstetric Acute Abdomen. The causes are discussed separately (for surgical pearls), laparoscopic approach and radiologic modality decision-making in pregnancy, which is an academic and a practice-based helpful summary. Results and Discussion: In addition, the sequence of ideas and language used in the article was based to help the reader understand the topic, rather than inform them about it. In addition, the utility of laparoscopy in pregnancy remains a concern due to the possible risk of injury to the fetus and fetal acidosis. Although, trials showed that laparoscopy was associated with less blood loss and a shorter hospital stay. Moreover, in some cases radiographic imaging is necessary, posing a diagnostic dilemma. Conclusion AAP is a major concern that requires early interventions to pinpoint the cause and manage the patient, properly.
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Affiliation(s)
- Humood A Alsadery
- Department of General Surgery, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Omar A Bamalan
- College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Hussain J Aljubran
- College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Lama J Albaish
- College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Basmah Z Al Ghanim
- College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
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Minoda A, Tsuda H, Masahashi Y, Nakamura T, Suzuki M, Fukuhara N, Ito Y, Tezuka A, Ando T, Mizuno K. Maternal Renal Dysfunction in Late Pregnancy in Twin and Singleton Pregnancies: Retrospective Study. J Clin Med 2022; 12:jcm12010090. [PMID: 36614889 PMCID: PMC9821260 DOI: 10.3390/jcm12010090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022] Open
Abstract
This study aimed to evaluate the differences in the impact on maternal renal function between singleton and twin pregnancies in the second half of pregnancy. It retrospectively enrolled 1711 pregnant women consisting of 1547 singleton pregnancies and 164 twin pregnancies from Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital from January 2019 to June 2021. Patients underwent renal function tests (serum blood urea nitrogen, creatinine, and estimated glomerular filtration rate (eGFR)) at least one month before delivery. The main outcome measure was maternal renal dysfunction, defined as a serum creatinine level above 0.8 mg/dL. The serum creatinine level was significantly higher and the eGFR was significantly lower in twin than in singleton pregnancies (p < 0.001). In addition, the rate of renal dysfunction was significantly higher in twin than in singleton pregnancies (7.9% vs. 2.6%; p < 0.01). Multivariate analysis revealed that twin pregnancy (odds ratio (OR) 3.38), nulliparity (OR 2.31), and preeclampsia (OR 3.64) were significant risk factors for maternal renal dysfunction. Maternal renal dysfunction was observed in 13 twin pregnancies, all of which recovered to within normal limits during the early months of the postpartum period. Twin pregnancy is a significant risk factor for maternal renal dysfunction; renal function should be carefully monitored in twin pregnancies.
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Reliability of Rodent and Rabbit Models in Preeclampsia Research. Int J Mol Sci 2022; 23:ijms232214344. [PMID: 36430816 PMCID: PMC9696504 DOI: 10.3390/ijms232214344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/14/2022] [Accepted: 11/14/2022] [Indexed: 11/22/2022] Open
Abstract
In vivo studies on the pathology of gestation, including preeclampsia, often use small mammals such as rabbits or rodents, i.e., mice, rats, hamsters, and guinea pigs. The key advantage of these animals is their short reproductive cycle; in addition, similar to humans, they also develop a haemochorial placenta and present a similar transformation of maternal spiral arteries. Interestingly, pregnant dams also demonstrate a similar reaction to inflammatory factors and placentally derived antiangiogenic factors, i.e., soluble fms-like tyrosine kinase 1 (sFlt-1) or soluble endoglin-1 (sEng), as preeclamptic women: all animals present an increase in blood pressure and usually proteinuria. These constitute the classical duet that allows for the recognition of preeclampsia. However, the time of initiation of maternal vessel remodelling and the depth of trophoblast invasion differs between rabbits, rodents, and humans. Unfortunately, at present, no known animal replicates a human pregnancy exactly, and hence, the use of rabbit and rodent models is restricted to the investigation of individual aspects of human gestation only. This article compares the process of placentation in rodents, rabbits, and humans, which should be considered when planning experiments on preeclampsia; these aspects might determine the success, or failure, of the study. The report also reviews the rodent and rabbit models used to investigate certain aspects of the pathomechanism of human preeclampsia, especially those related to incorrect trophoblast invasion, placental hypoxia, inflammation, or maternal endothelial dysfunction.
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Beers K, Patel N. Kidney Physiology in Pregnancy. Adv Chronic Kidney Dis 2020; 27:449-454. [PMID: 33328060 DOI: 10.1053/j.ackd.2020.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 11/11/2022]
Abstract
A woman's body undergoes a myriad of changes throughout the course of a normal gestation. The kidneys play a central role in driving adjustments that guarantee maternal and fetal well-being, including a dramatic increase in glomerular filtration rate, alterations in tubular function, and changes in electrolyte and acid/base handling. Early in gestation, systemic vasodilation, driven by both a change in quantity of and response to various hormones, leads to increased renal blood flow and glomerular filtration rate. Vasodilation also results in activation of the renin-angiotensin-aldosterone axis, which combined with changing tubular handling causes alterations in total body stores of electrolytes and total body water, resulting in a lower serum sodium concentration. In addition, mild proteinuria, glucosuria, and a decrease in serum calcium and magnesium are common. The primary acid/base change seen in pregnancy is a mild respiratory alkalosis due to progesterone effects. This article provides an overview of the current understanding of the healthy response of the kidneys to pregnancy, an understanding of which is key to caring for the pregnant patient, and early identification of alterations that may indicate underlying kidney pathology in pregnancy.
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Kazma JM, van den Anker J, Allegaert K, Dallmann A, Ahmadzia HK. Anatomical and physiological alterations of pregnancy. J Pharmacokinet Pharmacodyn 2020; 47:271-285. [PMID: 32026239 PMCID: PMC7416543 DOI: 10.1007/s10928-020-09677-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/28/2020] [Indexed: 02/07/2023]
Abstract
The extensive metabolic demands of pregnancy require specific physiological and anatomical changes. These changes affect almost all organ systems, including the cardiovascular, respiratory, renal, gastrointestinal, and hematologic system. The placenta adds another layer of complexity. These changes make it challenging for clinicians to understand presenting signs and symptoms, or to interpret laboratory and radiological tests. Furthermore, these physiological alterations can affect the pharmacokinetics and pharmacodynamics of drugs. Drug safety in lactation is only supported by limited evidence. In addition, the teratogenic effects of medications are often extrapolated from animals, which further adds uncertainties. Unfortunately, pregnant women are only rarely included in clinical drug trials, while doses, regimens, and side effects are often extrapolated from studies conducted in non-pregnant populations. In this comprehensive review, we present the changes occurring in each system with its effects on the pharmacokinetic variables. Understanding these physiological changes throughout normal pregnancy helps clinicians to optimize the health of pregnant women and their fetuses. Furthermore, the information on pregnancy-related physiology is also critical to guide study design in this vulnerable 'orphan' population, and provides a framework to explore pregnancy-related pathophysiology such as pre-eclampsia.
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Affiliation(s)
- Jamil M Kazma
- Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - John van den Anker
- Division of Clinical Pharmacology, Children's National Hospital, Washington, DC, USA
- Pediatric Pharmacology and Pharmacometrics, University of Basel Children's Hospital, Basel, Switzerland
| | - Karel Allegaert
- Department of Development and Regeneration, and Department of Pharmaceutical and Pharmacological Sciences, Leuven, Belgium
- Department of Clinical Pharmacy, Erasmus MC, Rotterdam, The Netherlands
| | - André Dallmann
- Clinical Pharmacometrics, Research & Development, Pharmaceuticals, Bayer AG, Leverkusen, Germany
| | - Homa K Ahmadzia
- Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
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Abstract
PURPOSE OF REVIEW Renal ion transport undergoes dramatic changes during the course of gestation. These adaptations are necessary to meet the dynamic requirements of pregnancy and support fetal development. Pregnancy is characterized by a high demand for both sodium and potassium. Recently there has been work in the field profiling the modifications of the renal tubules in pregnancy to meet these demands. The purpose of this review is to summarize these findings. RECENT FINDINGS The work to date suggests an important role for the distal nephron in both the renal sodium and potassium reabsorption during pregnancy. There is strong evidence that renal sodium reabsorption is mediated by the epithelial sodium channel (ENaC). Whereas renal potassium reabsorption is mediated by upregulation of potassium retaining transporters (HKA2) and downregulation of potassium secreting channels (ROMK, BK). SUMMARY Fetal growth restriction and hypertensive disorders of pregnancy including preeclampsia are marked by suboptimal maternal plasma volume expansion, which is determined by renal electrolyte handling. Therefore, understanding the physiologic demand for sodium and potassium in pregnancy and the adaptations required to support these needs is necessary for the effective treatment of diseased states of pregnancy.
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Turbeville HR, Taylor EB, Garrett MR, Didion SP, Ryan MJ, Sasser JM. Superimposed Preeclampsia Exacerbates Postpartum Renal Injury Despite Lack of Long-Term Blood Pressure Difference in the Dahl Salt-Sensitive Rat. Hypertension 2019; 73:650-658. [PMID: 30612494 PMCID: PMC6374193 DOI: 10.1161/hypertensionaha.118.12097] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Preeclampsia results in increased susceptibility to hypertension and chronic kidney disease postpartum; however, the mechanisms responsible for disease progression in these women remain unknown. The purpose of this study was to test the hypothesis that 2 mechanisms contribute to the link between the maternal syndrome of preeclampsia and the increased postpartum risk of cardiovascular and renal disease: (1) increased T cells in the kidney and (2) a decreased NO:ET-1 (endothelin-1) ratio. Dahl S rats (a previously characterized model of preeclampsia superimposed on chronic hypertension) who experienced 2 pregnancies and virgin littermate controls were studied at 6 months of age. Mean arterial pressure was measured via telemetry, and renal injury was assessed through both histological analysis and measurement of urinary markers including nephrin, podocalyxin, and KIM-1 (kidney injury marker 1). Contributing mechanisms were assessed through flow cytometric analysis of renal T cells, quantification of plasma TNF-α (tumor necrosis factor-α) and IL-10 (interleukin-10), and quantification of urinary concentrations of NO metabolites and ET-1. Although prior pregnancy did not exacerbate the hypertension at 6 months, this group showed greater renal injury compared with virgin littermates. Flow cytometric analyses revealed an increase in renal T cells after pregnancy, and cytokine analysis revealed a systemic proinflammatory shift. Finally, the NO:ET-1 ratio was reduced. These results demonstrate that the link between the maternal syndrome of superimposed preeclampsia and postpartum risk of chronic kidney disease could involve both immune system activation and dysregulation of the NO:ET-1 balance.
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Affiliation(s)
- Hannah R. Turbeville
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Erin B. Taylor
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael R. Garrett
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Sean P. Didion
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael J. Ryan
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jennifer M. Sasser
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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West CA, Sasser JM, Baylis C. The enigma of continual plasma volume expansion in pregnancy: critical role of the renin-angiotensin-aldosterone system. Am J Physiol Renal Physiol 2016; 311:F1125-F1134. [PMID: 27707703 PMCID: PMC6189751 DOI: 10.1152/ajprenal.00129.2016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 09/29/2016] [Indexed: 12/27/2022] Open
Abstract
Pregnancy is characterized by avid renal sodium retention and plasma volume expansion in the presence of decreased blood pressure. Decreased maternal blood pressure is a consequence of reduced systemic vascular tone, which results from an increased production of vasodilators [nitric oxide (NO), prostaglandins, and relaxin] and decreased vascular responsiveness to the potent vasoconstrictor (angiotensin II). The kidneys participate in this vasodilatory response, resulting in marked increases in renal plasma flow and glomerular filtration rate (GFR) during pregnancy. In women, sodium retention drives plasma volume expansion (∼40%) and is necessary for perfusion of the growing uterus and fetus. For there to be avid sodium retention in the presence of the potent natriuretic influences of increased NO and elevated GFR, there must be modifications of the tubules to prevent salt wasting. The purpose of this review is to summarize these adaptations.
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Affiliation(s)
- Crystal A West
- Department of Medicine, Georgetown University, Washington, District of Columbia;
| | - Jennifer M Sasser
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Chris Baylis
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
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9
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Abstract
Glomerular filtration rate (GFR) and renal plasma flow (RPF) increase by 40-65% and 50-85%, respectively, during normal pregnancy in women. Studies using the gravid rat as a model have greatly enhanced our understanding of mechanisms underlying these remarkable changes in the renal circulation during gestation. Hyperfiltration appears to be almost completely due to the increase in RPF, the latter attributable to profound reductions in both the renal afferent and efferent arteriolar resistances. The major pregnancy hormone involved is relaxin. The mediators downstream from relaxin include endothelin (ET) and nitric oxide (NO). New evidence indicates that relaxin increases vascular gelatinase activity during pregnancy, thereby converting big ET to ET(1-32), which leads to renal vasodilation, hyperfiltration, and reduced myogenic reactivity of small renal arteries via the endothelial ET(B) receptor and NO. Whether the chronic volume expansion characteristic of pregnancy contributes to the maintenance of gestational renal changes requires further investigation. Additional studies are also needed to further delineate the molecular basis of these mechanisms and, importantly, to investigate whether they apply to women.
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Affiliation(s)
- Kirk P Conrad
- Departments of Obstetrics, Gynecology and Reproductive Sciences, and Cell Biology and Physiology, University of Pittsburgh School of Medicine and Magee-Women's Research Institute, Pittsburgh, Pennsylvania 15213, 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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Hossain MA, Kocan M, Yao ST, Royce SG, Nair VB, Siwek C, Patil NA, Harrison IP, Rosengren KJ, Selemidis S, Summers RJ, Wade JD, Bathgate RAD, Samuel CS. A single-chain derivative of the relaxin hormone is a functionally selective agonist of the G protein-coupled receptor, RXFP1. Chem Sci 2016; 7:3805-3819. [PMID: 30155023 PMCID: PMC6013806 DOI: 10.1039/c5sc04754d] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/24/2016] [Indexed: 11/24/2022] Open
Abstract
A single-chain derivative of the relaxin hormone ameliorates fibrosis without side-effects.
Human gene-2 relaxin (H2 relaxin) is a pleiotropic hormone with powerful vasodilatory and anti-fibrotic properties which has led to its clinical evaluation and provisional FDA approval as a treatment for acute heart failure. The diverse effects of H2 relaxin are mediated via its cognate G protein coupled-receptor (GPCR), Relaxin Family Peptide Receptor (RXFP1), leading to stimulation of a combination of cell signalling pathways that includes cyclic adenosine monophosphate (cAMP) and extracellular-signal-regulated kinases (ERK)1/2. However, its complex two-chain (A and B), disulfide-rich insulin-like structure is a limitation to its facile preparation, availability and affordability. Furthermore, its strong activation of cAMP signaling is likely responsible for reported detrimental tumor-promoting actions that may preclude long-term use of this drug for treating human disease. Here we report the design and synthesis of a H2 relaxin B-chain-only analogue, B7-33, which was shown to bind to RXFP1 and preferentially activate the pERK pathway over cAMP in cells that endogenously expressed RXFP1. Thus, B7-33 represents the first functionally selective agonist of the complex GPCR, RXFP1. Importantly, this small peptide agonist prevented or reversed organ fibrosis and dysfunction in three pre-clinical rodent models of heart or lung disease with similar potency to H2 relaxin. The molecular mechanism behind the strong anti-fibrotic actions of B7-33 involved its activation of RXFP1-angiotensin II type 2 receptor heterodimers that induced selective downstream signaling of pERK1/2 and the collagen-degrading enzyme, matrix metalloproteinase (MMP)-2. Furthermore, in contrast to H2 relaxin, B7-33 did not promote prostate tumor growth in vivo. Our results represent the first known example of the minimisation of a two-chain cyclic insulin-like peptide to a single-chain linear peptide that retains potent beneficial agonistic effects.
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Affiliation(s)
- Mohammed Akhter Hossain
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Martina Kocan
- Monash Institute of Pharmaceutical Sciences , Monash University , Victoria , Australia
| | - Song T Yao
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ;
| | - Simon G Royce
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
| | - Vinojini B Nair
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Christopher Siwek
- Monash Institute of Pharmaceutical Sciences , Monash University , Victoria , Australia
| | - Nitin A Patil
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Ian P Harrison
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
| | - K Johan Rosengren
- The University of Queensland , School of Biomedical Sciences , Brisbane , QLD 4072 , Australia
| | - Stavros Selemidis
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
| | - Roger J Summers
- Monash Institute of Pharmaceutical Sciences , Monash University , Victoria , Australia
| | - John D Wade
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Ross A D Bathgate
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,Department of Biochemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Chrishan S Samuel
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
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Hadlow N, Sikaris K. Aspects to Consider in Adopting Pregnancy-Specific Reference Intervals. Clin Biochem Rev 2015; 36:127-132. [PMID: 26900191 PMCID: PMC4743620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Narelle Hadlow
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, WA
- School of Pathology and Laboratory Medicine, University of Western Australia, Perth, WA
| | - Ken Sikaris
- Department of Pathology, Melbourne Pathology, Melbourne, Vic., Australia
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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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14
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West CA, McDonough AA, Masilamani SME, Verlander JW, Baylis C. Renal NCC is unchanged in the midpregnant rat and decreased in the late pregnant rat despite avid renal Na+ retention. Am J Physiol Renal Physiol 2015; 309:F63-70. [PMID: 25925254 DOI: 10.1152/ajprenal.00147.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 04/22/2015] [Indexed: 11/22/2022] Open
Abstract
Pregnancy is characterized by plasma volume expansion due to Na(+) retention, driven by aldosterone. The aldosterone-responsive epithelial Na(+) channel is activated in the kidney in pregnancy. In the present study, we investigated the aldosterone-responsive Na(+)-Cl(-) cotransporter (NCC) in mid- and late pregnant rats compared with virgin rats. We determined the abundance of total NCC, phosphorylated NCC (pNCC; pT53, pS71 and pS89), phosphorylated STE20/SPS-1-related proline-alanine-rich protein kinase (pSPAK; pS373), and phosphorylated oxidative stress-related kinase (pOSR1; pS325) in the kidney cortex. We also measured mRNA expression of NCC and members of the SPAK/NCC regulatory kinase network, serum and glucocorticoid-regulated kinase (SGK)1, total with no lysine kinase (WNK)1, WNK3, and WNK4. Additionally, we performed immunohistochemistry for NCC kidneys from virgin and pregnant rats. Total NCC, pNCC, and pSPAK/OSR1 abundance were unchanged in midpregnant versus virgin rats. In late pregnant versus virgin rats, total NCC and pNCC were decreased; however, pSPAK/OSR1 was unchanged. We detected no differences in mRNA expression of NCC, SGK1, total WNK1, WNK3, and WNK4. By immunohistochemistry, NCC was mainly localized to the apical region in virgin rats, and density in the apical region was reduced in late pregnancy. Therefore, despite high circulating aldosterone levels in pregnancy, the aldosterone-responsive transporter NCC is not increased in total or activated (phosphorylated) abundance or in apical localization in midpregnant rats, and all are reduced in late pregnancy. This contrasts to the mineralocorticoid-mediated activation of the epithelial Na(+) channel, which we have previously reported. Why and how NCC escapes aldosterone activation in pregnancy is not clear but may relate to regional differences in aldosterone sensitivity the increased K(+) intake or other undefined mechanisms.
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Affiliation(s)
- Crystal A West
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida;
| | - Alicia A McDonough
- Department of Cell and Neurobiology, Keck School of Medicine of University of Southern California, Los Angeles, California; and
| | - Shyama M E Masilamani
- Department of Internal Medicine, Virginia Commonwealth University Medical Center, Richmond, Virginia
| | - Jill W Verlander
- Department of Medicine, University of Florida, Gainesville, Florida
| | - Chris Baylis
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida; Department of Medicine, University of Florida, Gainesville, Florida
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15
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Cunningham MW, West CA, Wen X, Deng A, Baylis C. Pregnant rats treated with a high-fat/prooxidant Western diet with ANG II and TNF-α are resistant to elevations in blood pressure and renal oxidative stress. Am J Physiol Regul Integr Comp Physiol 2015; 308:R945-56. [PMID: 25810384 DOI: 10.1152/ajpregu.00141.2014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 03/17/2015] [Indexed: 01/19/2023]
Abstract
Oxidative stress and inflammation are risk factors for hypertension in pregnancy. Here, we examined the 24-h mean arterial pressure (MAP) via telemetry and the nitric oxide (NO) and redox systems in the kidney cortex, medulla, and aorta of virgin and pregnant rats treated with a high-fat/prooxidant Western diet (HFD), ANG II, and TNF-α. Female Sprague-Dawley rats were given a normal diet (ND) or a HFD for 8 wk before mating. Day 6 of pregnancy and age-matched virgins were implanted with minipumps infusing saline or ANG II (150 ng·kg(-1)·min(-1)) + TNF-α (75 ng/day) for 14 days. Groups consisted of Virgin + ND + Saline (V+ND) (n = 7), Virgin + HFD +ANG II and TNF-α (V+HFD) (n = 7), Pregnant + ND + Saline (P+ND) (n = 6), and Pregnant + HFD + ANG II and TNF-α (P+HFD) (n = 8). After day 6 of minipump implantation, V+HFD rats displayed an increase in MAP on days 7, 8, and 10-15 vs. V+ND rats. P+HFD rats, after day 6 of minipump implantation, showed an increase in MAP only on day 7 vs. P+ND rats. P+HFD rats had a normal fall in 24-h MAP, hematocrit, plasma protein concentration, and osmolality at late pregnancy. No change in kidney cortex, medulla, or aortic oxidative stress in P+HFD rats. P+HFD rats displayed a decrease in nNOSβ abundance, but no change in kidney cortex NOx content vs. P+ND rats. Pregnant rats subjected to a chronic HFD and prooxidant and proinflammatory insults have a blunted increase in 24-h MAP and renal oxidative stress. Our data suggest renal NO bioavailability is not altered in pregnant rats treated with a HFD, ANG II, and TNF-α.
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Affiliation(s)
- Mark W Cunningham
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi;
| | - Crystal A West
- Department of Physiology and Functional Genomics, Department of Medicine, University of Florida College of Medicine, Gainesville, Florida; and
| | - Xuerong Wen
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida College of Medicine, Gainesville, Florida
| | - Aihua Deng
- Department of Physiology and Functional Genomics, Department of Medicine, University of Florida College of Medicine, Gainesville, Florida; and
| | - Chris Baylis
- Department of Physiology and Functional Genomics, Department of Medicine, University of Florida College of Medicine, Gainesville, Florida; and Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida College of Medicine, Gainesville, Florida
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16
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George EM. New approaches for managing preeclampsia: clues from clinical and basic research. Clin Ther 2014; 36:1873-1881. [PMID: 25450475 PMCID: PMC4268345 DOI: 10.1016/j.clinthera.2014.09.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 09/25/2014] [Indexed: 01/14/2023]
Abstract
PURPOSE One of the most common, and most vexing, obstetric complications is preeclampsia-a major cause of maternal and perinatal morbidity. Hallmarked by new-onset hypertension and a myriad of other symptoms, the underlying cause of the disorder remains obscure despite intensive research into its etiology. Although the initiating events are not clear, one common finding in preeclamptic patients is failure to remodel the maternal arteries that supply the placenta, with resulting hypoxia/ischemia. Intensive research over the past 2 decades has identified several categories of molecular dysfunction resulting from placental hypoxia, which, when released into the maternal circulation, are involved in the spectrum of symptoms seen in these patients-in particular, angiogenic imbalance and the activation of innate and adaptive immune responses. Despite these new insights, little in the way of new treatments for the management of these patients has been advanced into clinical practice. Indeed, few therapeutic options exist for the obstetrician treating a case of preeclampsia. Pharmacologic management is typically seizure prophylaxis, and, in severe cases, antihypertensive agents for controlling worsening hypertension. Ultimately, the induction of labor is indicated, making preeclampsia a leading cause of premature birth. Here, the molecular mechanisms linking placental ischemia to the maternal symptoms of preeclampsia are reviewed, and several areas of recent research suggesting new potential therapeutic approaches to the management of preeclampsia are identified.
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Affiliation(s)
- Eric M George
- Departments of Physiology and Biophysics, and Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi.
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17
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van Drongelen J, de Vries R, Lotgering FK, Smits P, Spaanderman MEA. Functional vascular changes of the kidney during pregnancy in animals: a systematic review and meta-analysis. PLoS One 2014; 9:e112084. [PMID: 25386682 PMCID: PMC4227845 DOI: 10.1371/journal.pone.0112084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 10/12/2014] [Indexed: 11/18/2022] Open
Abstract
Renal vascular responses to pregnancy have frequently been studied, by investigating renal vascular resistance (RVR), renal flow, glomerular filtration rate (GFR), and renal artery responses to stimuli. Nonetheless, several questions remain: 1. Which vasodilator pathways are activated and to what extent do they affect RVR, renal flow and GFR across species, strains and gestational ages, 2. Are these changes dependent on renal artery adaptation, 3. At which cellular level does pregnancy affect the involved pathways? In an attempt to answer the questions raised, we performed a systematic review and meta-analysis on animal data. We included 37 studies (116 responses). At mid-gestation, RVR and GFR change to a similar degree across species and strains, accompanied by variable change in renal flow. At least in rats, changes depend on NO activation. At late gestation, changes in RVR, renal flow and GFR vary between species and strains. In rats, these changes are effectuated by sympathetic stimulation. Overall, renal artery responsiveness to stimuli is unaffected by pregnancy, except for Sprague Dawley rats in which pregnancy enhances renal artery vascular compliance and reduces renal artery myogenic reactivity. Our meta-analysis shows that: 1. Pregnancy changes RVR, renal flow and GFR dependent on NO-activation and sympathetic de-activation, but adjustments are different among species, strains and gestational ages; 2. These changes do not depend on adaptation of renal artery responsiveness; 3. It remains unknown at which cellular level pregnancy affects the pathways. Our meta-analysis suggests that renal changes during pregnancy in animals are qualitatively similar, even in comparison to humans, but quantitatively different.
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Affiliation(s)
- Joris van Drongelen
- Department of Obstetrics and Gynecology, Radboudumc, the Netherlands
- * E-mail:
| | - Rob de Vries
- Systematic Review Centre for Laboratory animal Experimentation, Radboudumc, the Netherlands
| | | | - Paul Smits
- Department of Pharmacology and Toxicology, Radboudumc, the Netherlands
| | - Marc E. A. Spaanderman
- Department of Obstetrics and Gynecology, Radboudumc, the Netherlands
- Department of Obstetrics and Gynecology, Research School GROW, Maastricht University Medical Centre, Maastricht, the Netherlands
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18
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Conrad KP, Davison JM. The renal circulation in normal pregnancy and preeclampsia: is there a place for relaxin? Am J Physiol Renal Physiol 2014; 306:F1121-35. [PMID: 24647709 DOI: 10.1152/ajprenal.00042.2014] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
During the first trimester of human pregnancy, the maternal systemic circulation undergoes remarkable vasodilation. The kidneys participate in this vasodilatory response resulting in marked increases in renal plasma flow (RPF) and glomerular filtration rate (GFR). Comparable circulatory adaptations are observed in conscious gravid rats. Administration of the corpus luteal hormone relaxin (RLN) to nonpregnant rats and humans elicits vasodilatory changes like those of pregnancy. Systemic and renal vasodilation are compromised in midterm pregnant rats by neutralization or elimination of circulating RLN and in women conceiving with donor eggs who lack a corpus luteum and circulating RLN. Although RLN exerts both rapid (minutes) and sustained (hours to days) vasodilatory actions through different molecular mechanisms, a final common pathway is endothelial nitric oxide. In preeclampsia (PE), maternal systemic and renal vasoconstriction leads to hypertension and modest reduction in GFR exceeding that of RPF. Elevated level of circulating soluble vascular endothelial growth factor receptor-1 arising from the placenta is implicated in the hypertension and disruption of glomerular fenestrae and barrier function, the former causing reduced Kf and the latter proteinuria. Additional pathogenic factors are discussed. Last, potential clinical ramifications include RLN replacement in women conceiving with donor eggs and its therapeutic use in PE. Another goal has been to apply knowledge gained from investigating circulatory adaptations in pregnancy toward identifying and developing novel therapeutic strategies for renal and cardiovascular disease in the nonpregnant population. So far, one candidate to emerge is RLN and its potential therapeutic use in heart failure.
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Affiliation(s)
- Kirk P Conrad
- Departments of Physiology and Functional Genomics and Obstetrics and Gynecology, D. H. Barron Reproductive and Perinatal Biology Research Program, University of Florida College of Medicine, Gainesville, Florida; and
| | - John M Davison
- Institute of Cellular Medicine and Royal Victoria Infirmary, Newcastle University and Newcastle Hospitals National Health Service Foundation Trust, Newcastle Upon Tyne, United Kingdom
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West CA, Shaw S, Sasser JM, Fekete A, Alexander T, Cunningham MW, Masilamani SME, Baylis C. Chronic vasodilation increases renal medullary PDE5A and α-ENaC through independent renin-angiotensin-aldosterone system pathways. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1133-40. [PMID: 24068049 PMCID: PMC3841800 DOI: 10.1152/ajpregu.00003.2013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 09/19/2013] [Indexed: 02/05/2023]
Abstract
We have previously observed that many of the renal and hemodynamic adaptations seen in normal pregnancy can be induced in virgin female rats by chronic systemic vasodilation. Fourteen-day vasodilation with sodium nitrite or nifedipine (NIF) produced plasma volume expansion (PVE), hemodilution, and increased renal medullary phosphodiesterase 5A (PDE5A) protein. The present study examined the role of the renin-angiotensin-aldosterone system (RAAS) in this mechanism. Virgin females were treated for 14 days with NIF (10 mg·kg(-1)·day(-1) via diet), NIF with spironolactone [SPR; mineralocorticoid receptor (MR) blocker, 200-300 mg·kg(-1)·day(-1) via diet], NIF with losartan [LOS; angiotensin type 1 (AT1) receptor blocker, 20 mg·kg(-1)·day(-1) via diet], enalapril (ENAL; angiotensin-converting enzyme inhibitor, 62.5 mg/l via water), or vehicle (CON). Mean arterial pressure (MAP) was reduced 7.4 ± 0.5% with NIF, 6.33 ± 0.5% with NIF + SPR, 13.3 ± 0.9% with NIF + LOS, and 12.0 ± 0.4% with ENAL vs. baseline MAP. Compared with CON (3.6 ± 0.3%), plasma volume factored for body weight was increased by NIF (5.2 ± 0.4%) treatment but not by NIF + SPR (4.3 ± 0.3%), NIF + LOS (3.6 ± 0.1%), or ENAL (4.0 ± 0.3%). NIF increased PDE5A protein abundance in the renal inner medulla, and SPR did not prevent this increase (188 ± 16 and 204 ± 22% of CON, respectively). NIF increased the α-subunit of the epithelial sodium channel (α-ENaC) protein in renal outer (365 ± 44%) and inner (526 ± 83%) medulla, and SPR prevented these changes. There was no change in either PDE5A or α-ENaC abundance vs. CON in rats treated with NIF + LOS or ENAL. These data indicate that the PVE and renal medullary adaptations in response to chronic vasodilation result from RAAS signaling, with increases in PDE5A mediated through AT1 receptor and α-ENaC through the MR.
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Affiliation(s)
- Crystal A West
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
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20
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Kazama I, Matsubara M, Kanai Y, Hatano R, Asano S, Endo Y, Toyama H, Ejima Y, Kurosawa S, Maruyama Y. Decreased expression of a novel prostaglandin transporter, OAT-PG, facilitates renocortical PGE2 accumulation during rat pregnancy. Gynecol Obstet Invest 2013; 76:163-70. [PMID: 24008262 DOI: 10.1159/000353977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 06/19/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Prostaglandin (PG)-specific organic anion transporter (OAT-PG) is a recently identified renal transporter involved in the local clearance of prostaglandin E2 (PGE2). Since the renal biosynthesis of PGE2 is not increased during pregnancy, this transporter expression would affect the gestational changes in the renal PGE2 content. METHODS Kidneys from rats at different gestational stages were used to examine gestational changes in the renocortical PGE2 concentration. The renal expression of OAT-PG and the enzymes for PGE2 synthesis was also examined sequentially, together with the gestational changes in renal renin production. RESULTS The renocortical PGE2 concentration was significantly increased during midterm to late pregnancy, with a maximum increase of 47.6 ± 11.5% from the virgin value. Although the expression of the enzymes, such as cyclooxygenases and PG synthases, was not increased, that of OAT-PG was significantly decreased throughout pregnancy, inversely correlating with changes in the renocortical PGE2 concentration. Renal renin production was significantly increased during pregnancy. CONCLUSION This study demonstrated for the first time that the tissue PGE2 concentration was increased in pregnant rat kidneys, which may be associated with the gestational rise in glomerular filtration rate. The decreased expression of OAT-PG was thought to be responsible for the increased tissue PGE2 content.
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Affiliation(s)
- Itsuro Kazama
- Department of Physiology I, Tohoku University Graduate School of Medicine, Sendai, Japan
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21
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George EM, Palei AC, Dent EA, Granger JP. Sildenafil attenuates placental ischemia-induced hypertension. Am J Physiol Regul Integr Comp Physiol 2013; 305:R397-403. [PMID: 23785075 DOI: 10.1152/ajpregu.00216.2013] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Preeclampsia is a complication of pregnancy that is marked by hypertension, proteinuria, and maternal endothelial dysfunction. A central factor in the etiology of the disease is the development of placental hypoxia/ischemia, which releases pathogenic soluble factors. There is currently no effective treatment for preeclampsia, but the phosphodiesterase-5 (PDE-5) inhibitor sildenafil has been suggested, as PDE-5 is enriched in the uterus, and its antagonism could improve uteroplacental function. Here, we report in the reduced uterine perfusion pressure (RUPP) rat model that administration of oral sildenafil is effective in attenuating placental ischemia-induced hypertension during gestation. RUPP animals have significantly elevated arterial pressure compared with control animals (132 ± 3 vs. 100 ± 2 mmHg; P < 0.05). Administration of oral sildenafil (45 mg·kg⁻¹·day⁻¹) had no effect on blood pressure in control rats but decreased pressure in RUPP rats (115 ± 1 mmHg; P < 0.05). RUPP induced changes in placental sFlt-1, and vascular endothelial growth factor (VEGF) was unaffected by sildenafil administration, as was the decrease in free plasma VEGF. RUPP animals had a significant increase in medullary PDE-5/β-actin ratio (1 ± 0.14 vs. 1.63 ± 0.18; P < 0.05) expression with a resulting reduction in renal medullary cGMP (1.5 ± 0.15 vs. 0.99 ± 0.1 pmol/μg protein, P < 0.05) compared with controls. Although sildenafil had no effect on renal medullary cGMP in control animals, it significantly increased cGMP in RUPP animals (1.3 ± 0.1 pmol/μg protein; P < 0.05). These data suggest that sildenafil might provide an effective therapeutic option for the management of hypertension during preeclampsia.
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Affiliation(s)
- Eric M George
- Department of Physiology and the Cardiovascular Renal Research Center, The University of Mississippi Medical Center, Jackson, Mississippi
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22
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Bathgate RAD, Halls ML, van der Westhuizen ET, Callander GE, Kocan M, Summers RJ. Relaxin family peptides and their receptors. Physiol Rev 2013; 93:405-80. [PMID: 23303914 DOI: 10.1152/physrev.00001.2012] [Citation(s) in RCA: 371] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
There are seven relaxin family peptides that are all structurally related to insulin. Relaxin has many roles in female and male reproduction, as a neuropeptide in the central nervous system, as a vasodilator and cardiac stimulant in the cardiovascular system, and as an antifibrotic agent. Insulin-like peptide-3 (INSL3) has clearly defined specialist roles in male and female reproduction, relaxin-3 is primarily a neuropeptide involved in stress and metabolic control, and INSL5 is widely distributed particularly in the gastrointestinal tract. Although they are structurally related to insulin, the relaxin family peptides produce their physiological effects by activating a group of four G protein-coupled receptors (GPCRs), relaxin family peptide receptors 1-4 (RXFP1-4). Relaxin and INSL3 are the cognate ligands for RXFP1 and RXFP2, respectively, that are leucine-rich repeat containing GPCRs. RXFP1 activates a wide spectrum of signaling pathways to generate second messengers that include cAMP and nitric oxide, whereas RXFP2 activates a subset of these pathways. Relaxin-3 and INSL5 are the cognate ligands for RXFP3 and RXFP4 that are closely related to small peptide receptors that when activated inhibit cAMP production and activate MAP kinases. Although there are still many unanswered questions regarding the mode of action of relaxin family peptides, it is clear that they have important physiological roles that could be exploited for therapeutic benefit.
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Affiliation(s)
- R A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Monash University, Victoria, Australia
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23
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Cunningham MW, Sasser JM, West CA, Baylis C. Renal redox response to normal pregnancy in the rat. Am J Physiol Regul Integr Comp Physiol 2013; 304:R443-9. [PMID: 23283939 DOI: 10.1152/ajpregu.00496.2012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Normal pregnancy involves increased renal sodium reabsorption, metabolism, and oxygen consumption, which can cause increased oxidative stress (OS). OS can decrease nitric oxide (NO) bioavailability and cause pregnancy complications. In this study we examined the NO synthases (NOS) and redox state in the kidney cortex and aorta in early (E), mid (M), and late (L) pregnant (P) (days 3, 12, 20) and 2-4 days postpartum (PP) rats compared with virgin rats (V). Protein abundance of endothelial NOS (eNOS) was unchanged and neuronal NOS (nNOS)α fell at LP in the kidney cortex. Kidney cortex nNOSβ was elevated at MP, LP, and PP. No changes in aortic NOS isoforms were observed. Kidney cortex nitrotyrosine (NT) abundance decreased in EP, MP, and PP, whereas aortic NT increased in EP, MP, and PP. The NADPH oxidase subunit p22phox decreased in the kidney cortex at EP while aortic p22phox increased in EP and LP. No changes in kidney cortex NADPH-dependent superoxide production or hydrogen peroxide levels were noted. Kidney cortex cytosolic (CuZn) superoxide dismutase (SOD) was unchanged, while mitochondrial SOD decreased at EP and extracellular SOD decreased at MP and LP in the kidney cortex. Despite falls in abundance of kidney cortex SODs, total antioxidant capacity (TAC) was elevated in EP, MP, and PP in the kidney cortex. Aortic CuZn SOD deceased at PP, while the other aortic SODs and aortic TAC did not change. Data from this study suggest that the kidney cortex is protected from OS during normal rat pregnancy via an increase in antioxidant activity.
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Affiliation(s)
- Mark W Cunningham
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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Willcox JM, Summerlee AJS, Murrant CL. Relaxin induces rapid, transient vasodilation in the microcirculation of hamster skeletal muscle. J Endocrinol 2013; 218:179-91. [PMID: 23720398 DOI: 10.1530/joe-13-0115] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Relaxin produces a sustained decrease in total peripheral resistance, but the effects of relaxin on skeletal muscle arterioles, an important contributor to systemic resistance, are unknown. Using the intact, blood-perfused hamster cremaster muscle preparation in situ, we tested the effects of relaxin on skeletal muscle arteriolar microvasculature by applying 10(-10) M relaxin to second-, third- and fourth-order arterioles and capillaries. The mechanisms responsible for relaxin-induced dilations were explored by applying 10(-10) M relaxin to second-order arterioles in the presence of 10(-5) M N(G)-nitro-l-arginine methyl ester (l-NAME, nitric oxide (NO) synthase inhibitor), 10(-5) M glibenclamide (GLIB, ATP-dependent potassium (K(+)) channel inhibitor), 10(-3) M tetraethylammonium (TEA) or 10(-7) M iberiotoxin (IBTX, calcium-associated K(+) channel inhibitor). Relaxin caused second- (peak change in diameter: 8.3 ± 1.7 μm) and third (4.5 ± 1.1 μm)-order arterioles to vasodilate transiently while fourth-order arterioles did not (0.01 ± 0.04 μm). Relaxin-induced vasodilations were significantly inhibited by l-NAME, GLIB, TEA and IBTX. Relaxin stimulated capillaries to induce a vasodilation in upstream fourth-order arterioles (2.1 ± 0.3 μm), indicating that relaxin can induce conducted responses vasodilation that travels through blood vessel walls via gap junctions. We confirmed gap junction involvement by showing that gap junction uncouplers (18-β-glycyrrhetinic acid (40 × 10(-6) M) or 0.07% halothane) inhibited upstream vasodilations to localised relaxin stimulation of second-order arterioles. Therefore, relaxin produces transient NO- and K(+) channel-dependent vasodilations in skeletal muscle arterioles and stimulates capillaries to initiate conducted responses. The transient nature of the arteriolar dilation brings into question the role of skeletal muscle vascular beds in generating the sustained systemic haemodynamic effects induced by relaxin.
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Affiliation(s)
- Jordan M Willcox
- Department of Biomedical Sciences Human Health, University of Guelph, ANNU Bldg, Room 350, Guelph, Ontario, Canada N1G 2W1
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25
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Odutayo A, Hladunewich M. Obstetric Nephrology: Renal Hemodynamic and Metabolic Physiology in Normal Pregnancy. Clin J Am Soc Nephrol 2012; 7:2073-80. [DOI: 10.2215/cjn.00470112] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Preeclampsia is an important obstetric complication that arises in 5% of women after the 20(th) week of gestation, for which there is no specific therapy and no cure. Although much of the recent investigation in this field has focused on soluble forms of the angiogenic membrane receptor tyrosine kinase Flt1 and the transforming growth factor β co-receptor Endoglin, there is significant clinical potential for several GPCR targets and their agonists or antagonists in preeclampsia. In this review, we discuss several of the most promising candidates in this category, including calcitonin receptor-like receptor / receptor activity modifying protein 1 complexes, the angiotensin AT1, 2 and Mas receptors, and the relaxin receptor RXFP1. We also address some of the controversies surrounding the roles and therapeutic potential of these GPCRs and their (ant)agonists in preeclampsia.
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Affiliation(s)
- Jt McGuane
- D.H. Barron Reproductive and Perinatal Biology Outcomes Research Program, and Department of Physiology and Functional Genomics, and of Obstetrics and Gynecology, University of Florida College of Medicine, Gainesville, FL 32610
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Maternal adaptations and inheritance in the transgenerational programming of adult disease. Cell Tissue Res 2012; 349:863-80. [PMID: 22526629 DOI: 10.1007/s00441-012-1411-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 03/08/2012] [Indexed: 12/17/2022]
Abstract
Adverse exposures in utero have long been linked with an increased susceptibility to adult cardio-renal and metabolic diseases. Clear gender differences exist, whereby growth-restricted females, although exhibiting some phenotypic modifications, are often protected from overt disease outcomes. One of the greatest physiological challenges facing the female gender, however, is that of pregnancy; yet little research has focused on the outcomes associated with this, as a potential 'second-hit' for those who were small at birth. We review the limited evidence suggesting that pregnancy may unmask cardio-renal and metabolic disease states and the consequences for long-term maternal health in females who were born small. Additionally, a growing area of research in this programming field is in the transgenerational transmission of low birth weight and disease susceptibility. Pathways for transmission might include an abnormal adaptation to pregnancy by the growth-restricted mother and/or inheritance via the parental germline. Strategies to optimise the pregnancy environment and/or prevent the consequences of inheritance of programmed deficits and dysfunction are of critical importance for future generations.
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Abstract
Administering relaxin to conscious rats and humans elicits systemic and renal vasodilation. The molecular mechanisms vary according to the duration of relaxin exposure-so-called "rapid" (within minutes) or "sustained" (hours to days) vasodilatory responses-both being endothelium-dependent. Rapid responses are mediated by G(αi/o) protein coupling to phosphoinositol-3 kinase/Akt (protein kinase B)-dependent phosphorylation and activation of nitric oxide synthase. Sustained responses are mediated by vascular endothelial and placental growth factors, as well as increases in arterial gelatinase activity. Thus, after hours or days of relaxin treatment, respectively, arterial MMP-9 or MMP-2 hydrolyze "big" endothelin (ET) at a gly-leu bond to form ET(1-32), which in turn activates the endothelial ET(B) receptor/nitric oxide vasodilatory pathway. Administration of relaxin to conscious rats also increases global systemic arterial compliance and passive compliance of select isolated blood vessels such as small renal arteries (SRA). The increase in SRA passive compliance is mediated by both geometric remodeling (outward) and compositional remodeling (decreased collagen). Relaxin-induced geometric remodeling has also been observed in brain parenchymal arteries, and this remodeling appears to be via the activation of peroxisome proliferator-activated receptor-γ. Given the vasodilatory and arterial remodeling properties of relaxin, the hormone may have therapeutic potential in the settings of abnormal pregnancies, heart failure, and pathologies associated with stiffening of arteries.
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Abstract
Preeclampsia is one of the leading causes of maternal morbidity/mortality. The pathogenesis of preeclampsia is still under investigation. The aim of this paper is to present the molecular mechanisms implicating in the pathway leading to preeclampsia.
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Carvalho LN, Cristovam PC, Passos CS, Boim MA. Mesangial Cells Cultured from Pregnant Rats Display Reduced Reactivity to Angiotensin II: the Role of Relaxin, Nitric Oxide and AT2 Receptor. Cell Physiol Biochem 2012. [DOI: 10.1159/000343333] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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van Drongelen J, Pertijs J, Wouterse A, Hermsen R, Sweep FC, Lotgering FK, Smits P, Spaanderman ME. Contribution of different local vascular responses to mid-gestational vasodilation. Am J Obstet Gynecol 2011; 205:155.e12-7. [PMID: 21529754 DOI: 10.1016/j.ajog.2011.03.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/22/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE At-term pregnancy-induced vasodilation is the resultant of endothelium-dependent vasodilation, decreased myogenic reactivity, increased compliance, and reduced sensitivity to vasoconstrictor agents. We hypothesized that these vascular changes are already present at mid-gestation. STUDY DESIGN In 20 mid-pregnant and 20 nonpregnant Wistar Hannover rats, we measured vascular responses of isolated mesenteric arteries and kidney. RESULTS In the pregnant rats compared with the nonpregnant rats, mesenteric flow-mediated vasodilation and renal perfusion flow increased 1.52-fold (from 47±5 to 31±4 μL/min) and 1.13-fold (from 12.8±0.1 to 14.4±0.1 mL/min), respectively. Nitric oxide inhibition reduced mesenteric flow-mediated vasodilation to a similar extent in the pregnant and nonpregnant rats; it completely blocked the pregnancy-induced increase in renal perfusion flow. Pregnancy did not change mesenteric artery sensitivity to phenylephrine, myogenic reactivity, nor vascular compliance. CONCLUSION At mid-gestation, alterations in rat mesenteric vascular tone depend primarily on flow-mediated endothelium-dependent changes and not on changes in α-adrenergic vasoconstrictor sensitivity, myogenic reactivity, or vascular compliance.
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Abstract
Complicating up to 8% of pregnancies, preeclampsia is, in fact, the most common glomerular disease worldwide. In this article, we review the effect of normal pregnancy on the kidney as well as the role of the kidney in preeclampsia. We discuss blood pressure in pregnancy and preeclampsia, followed by the physiology of hyperfiltration in normal pregnancy as well as the pathophysiology of hypofiltration and proteinuria in preeclampsia. Recent studies have suggested that the clinical syndrome of preeclampsia, which recovers rapidly after delivery of the placenta, is caused by impaired vascular endothelial growth factor signaling that disturbs the status of vascular dilatation as well as the symbiosis between the glomerular endothelium and the podocytes. Finally, we discuss the intriguing association between chronic kidney disease (CKD) and preeclampsia. We hypothesize that the imbalance between angiogenic and anti-angiogenic factors, which may be common to both preeclampsia and CKD, might explain why CKD predisposes pregnant women to develop preeclampsia.
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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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Conrad KP. Maternal vasodilation in pregnancy: the emerging role of relaxin. Am J Physiol Regul Integr Comp Physiol 2011; 301:R267-75. [PMID: 21613576 DOI: 10.1152/ajpregu.00156.2011] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pregnancy is a unique physiological condition of profound maternal renal and systemic vasodilation. Our goal has been to unveil the reproductive hormones mediating this remarkable vasodilatory state and the underlying molecular mechanisms. In addition to advancing our knowledge of pregnancy physiology, reaching this goal may translate into therapeutics for pregnancy pathologies such as preeclampsia and for diseases associated with vasoconstriction and arterial stiffness in nonpregnant women and men. An emerging player is the 6 kDa corpus luteal hormone relaxin, which circulates during pregnancy. Relaxin administration to rats and humans induces systemic and renal vasodilation regardless of sex, thus mimicking the pregnant condition. Immunoneutralization or elimination of the source of circulating relaxin prevents renal and systemic vasodilation in midterm pregnant rats. Infertile women who become pregnant by donor eggs (IVF with embryo transfer) lack a corpus luteum and circulating relaxin, and they show a markedly subdued gestational increase in glomerular filtration rate. These data implicate relaxin as one of the vasodilatory reproductive hormones of pregnancy. There are different molecular mechanisms underlying the so-called rapid and sustained vasodilatory actions of relaxin. The former is mediated by Gα(i/o) protein coupling to phosphatidylinositol-3 kinase/Akt (protein kinase B)-dependent phosphorylation and activation of endothelial nitric oxide synthase, the latter by vascular endothelial and placental growth factors, and increases in arterial gelatinase(s) activity. The gelatinases, in turn, hydrolyze big endothelin (ET) at a gly-leu bond to form ET(1-32), which activates the endothelial ET(B) receptor/nitric oxide vasodilatory pathway.
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Affiliation(s)
- Kirk P Conrad
- Department of Physiology and Functional Genomics, Department of Obstetrics and Gynecology, University of Florida College of Medicine, Gainesville, Florida 32610, USA.
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McGuane JT, Danielson LA, Debrah JE, Rubin JP, Novak J, Conrad KP. Angiogenic growth factors are new and essential players in the sustained relaxin vasodilatory pathway in rodents and humans. Hypertension 2011; 57:1151-60. [PMID: 21536992 DOI: 10.1161/hypertensionaha.110.165027] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Relaxin is emerging as an important vasodilator of pregnancy and is being tested for afterload reduction in acute heart failure. However, the mechanisms underlying relaxin-induced vasodilation are incompletely understood. The aims of this study were to establish a new in vitro model for relaxin-induced vasodilation and to use this approach, as well as chronically instrumented, conscious rats, to investigate the role of angiogenic growth factors in the relaxin vasodilatory pathway. Incubation of rat and mouse small renal arteries with recombinant human H2 relaxin for 3 hours in vitro attenuated myogenic constriction, which was blocked by inhibitors of gelatinases, the endothelin B receptor, and NO synthase. These findings corroborate ex vivo observations in arteries isolated from relaxin-infused nonpregnant and midterm pregnant rats, thereby validating the new experimental approach and enabling the study of human arteries. Incubation of small human subcutaneous arteries with relaxin for 3 hours in vitro also attenuated myogenic constriction through the same molecular intermediates. Vascular endothelial growth factor receptor inhibitor SU5416, 3 different vascular endothelial growth factor, and 2 different placental growth factor neutralizing antibodies prevented relaxin from attenuating myogenic constriction in rat and mouse small renal and human subcutaneous arteries. SU5416 administration also prevented relaxin-induced renal vasodilation and hyperfiltration in chronically instrumented, conscious rats. Small renal arteries isolated from these rats demonstrated increased matrix metalloproteinase 2 activity in the relaxin-infused group, which was not prevented by SU5416. We conclude that there is concordance of relaxin vasodilatory mechanisms in rats, mice, and humans, and angiogenic growth factors are novel and essential intermediates.
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Affiliation(s)
- Jonathan T McGuane
- Department of Physiology and Functional Genomics and D H Barron Reproductive and Perinatal Biology Research Program, University of Florida College of Medicine, 1600 SW Archer Rd, M552, PO Box 100274, Gainesville, FL 32610-0274, USA.
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36
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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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Fekete A, Sasser JM, Baylis C. Chronic vasodilation produces plasma volume expansion and hemodilution in rats: consequences of decreased effective arterial blood volume. Am J Physiol Renal Physiol 2011; 300:F113-8. [PMID: 20980409 PMCID: PMC3023232 DOI: 10.1152/ajprenal.00478.2010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 10/21/2010] [Indexed: 11/22/2022] Open
Abstract
Plasma volume (PV) expansion is required for optimal pregnancy outcomes; however, the mechanisms responsible for sodium and water retention in pregnancy remain undefined. This study was designed to test the "arterial underfill hypothesis" of pregnancy which proposes that an enlarged vascular compartment (due to systemic vasodilation and shunting of blood to the placenta) results in renal sodium and water retention and PV expansion. We produced chronic vasodilation by 14 days administration of nifedipine (NIF; 10 mg·kg(-1)·day(-1)) or sodium nitrite (NaNO2; 70 mg·kg(-1)·day(-1)) to normal, nonpregnant female Sprague-Dawley rats. Mean arterial pressure, monitored by telemetry, was reduced by both NIF and NaNO2 but was unchanged in control rats. At day 14, vasodilator treatment lowered hematocrit and increased PV (determined by Evans blue dye dilution). Plasma osmolarity (Posm), sodium (PNa), and total protein concentrations all fell. These responses resemble the responses to normal pregnancy with hemodilution, marked PV expansion, and decreased Posm and PNa. Our previous work indicates a role of increased inner medullary phosphodiesterase-5 (PDE5) in the sodium retention of pregnancy. Here, we found that inner medullary PDE5A mRNA and protein expression were increased by both NIF and NaNO2 treatment vs. control; however, neither renal cortical nor aortic PDE5 expression was changed by vasodilator treatment. We suggest that a primary, persistent vasodilation drives increased inner medullary PDE5 expression which facilitates continual renal Na retention causing "refilling" of the vasculature and volume expansion.
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Affiliation(s)
- Andrea Fekete
- Department of Physiology and Functional Genomics, University of Florida, PO Box 100274, Gainesville, FL 32610, USA
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Smith CA, Santymire B, Erdely A, Venkat V, Losonczy G, Baylis C. Renal nitric oxide production in rat pregnancy: role of constitutive nitric oxide synthases. Am J Physiol Renal Physiol 2010; 299:F830-6. [PMID: 20630934 PMCID: PMC2957259 DOI: 10.1152/ajprenal.00300.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 07/10/2010] [Indexed: 11/22/2022] Open
Abstract
Functional studies show that increased renal nitric oxide (NO) mediates the renal vasodilation and increased glomerular filtration rate that occur during normal pregnancy. We investigated whether changes in the constitutive NO synthases (NOS), endothelial (eNOS) and neuronal (nNOS), were associated with the increased renal NO production in normal midterm pregnancy in the rat. In kidneys from midterm pregnant (MP: 11-13 days gestation), late-term pregnant (LP: 18-20 days gestation), and similarly aged virgin (V) rats, transcript and protein abundance for eNOS and the nNOSα and nNOSβ splice variants, as well as the rate of L-arginine-to-L-citrulline conversion, were determined as a measure of NOS activity. At MP, renal cortical abundance of the total eNOS protein and phosphorylated (Ser(1177)) eNOS was reduced, and L-arginine-to-L-citrulline conversion in the cortical membrane fraction was decreased; these declines were also seen in LP. There were no changes in the eNOS transcript. In contrast, L-arginine-to-L-citrulline conversion in the soluble fraction of renal cortex increased at MP and then declined at LP. This MP increase was ablated by S-methylthiocitrulline, a nNOS inhibitor. Using Western blotting, we did not detect a change in the protein abundance or transcript of the 160-kDa nNOSα, but protein abundance and transcript of the nNOSβ were increased at MP in cortex. Collectively, these studies suggest that the soluble nNOSβ is responsible for the increased renal cortical NO production during pregnancy.
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Affiliation(s)
- Cheryl A Smith
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
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Sasser JM, Ni XP, Humphreys MH, Baylis C. Increased renal phosphodiesterase-5 activity mediates the blunted natriuretic response to a nitric oxide donor in the pregnant rat. Am J Physiol Renal Physiol 2010; 299:F810-4. [PMID: 20668100 DOI: 10.1152/ajprenal.00117.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pregnancy is characterized by plasma volume expansion and renal sodium retention with loss of natriuretic response to atrial natriuretic peptide due to increased medullary phosphodiesterase-5 (PDE5). Here, we determined whether natriuretic responses to nitric oxide (NO) are also blunted in pregnancy due to increased PDE5. Anesthetized 16-day pregnant and virgin rats were studied at baseline and during intrarenal infusion of the NO donor spermine NONOate (2.5 nmol/min), the PDE5 inhibitor sildenafil (SILD; 0.5 μg/min), or a combination. The right (noninfused) kidney served as a control. Intrarenal NONOate had no effect on mean arterial pressure (MAP); however, SILD reduced MAP in virgin rats, and the combination of NONOate+SILD reduced MAP in both virgin and pregnant rats. Neither NONOate nor SILD altered glomerular filtration rate. NONOate and SILD each stimulated sodium excretion (U(Na)V) and fractional excretion of sodium (FE(Na)) in virgin rats, but the combination did not result in an additional natriuretic response. However, NONOate infusion did not increase U(Na)V or FE(Na) in pregnant rats, but the natriuretic response to NONOate was restored with SILD, and SILD alone produced a natriuresis during pregnancy. Sodium nitroprusside (10(-4) mol/l)-stimulated cGMP accumulation from inner medullary collecting duct cells was blunted in cells from pregnant vs. virgin or postpartum rats and was restored by treatment with the PDE5 inhibitor DMPPO (10(-7) mol/l). Therefore, increased intrarenal PDE5 mediates the blunted natriuretic response to NO, and loss of responsiveness to the cGMP-dependent, natriuretic agents may contribute to volume expansion during pregnancy.
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Affiliation(s)
- Jennifer M Sasser
- Dept. of Physiology and Functional Genomics, Univ. of Florida, PO Box 100274, Gainesville, FL 32610, USA.
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Conrad KP. Unveiling the vasodilatory actions and mechanisms of relaxin. Hypertension 2010; 56:2-9. [PMID: 20497994 PMCID: PMC3392655 DOI: 10.1161/hypertensionaha.109.133926] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 04/16/2010] [Indexed: 11/16/2022]
Affiliation(s)
- Kirk P Conrad
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1600 SW Archer Rd, M552, PO Box 100274, Gainesville, FL 32610, USA.
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Brooks VL, Mulvaney JM, Azar AS, Zhao D, Goldman RK. Pregnancy impairs baroreflex control of heart rate in rats: role of insulin sensitivity. Am J Physiol Regul Integr Comp Physiol 2009; 298:R419-26. [PMID: 19939977 DOI: 10.1152/ajpregu.00441.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies in rabbits suggest that insulin resistance and reduced brain insulin contribute to impaired baroreflex control of heart rate (HR) during pregnancy; however, the mechanisms are unknown. The rat model is ideal to investigate these mechanisms because much is known about rat brain baroreflex neurocircuitry and insulin receptor locations. However, it is unclear in rats whether pregnancy impairs the HR baroreflex or whether insulin resistance is involved. Therefore, this study tested the hypothesis that in rats pregnancy decreases HR baroreflex sensitivity (BRS) and that this decrease is related to concurrent decreases in insulin sensitivity (IS). BRS was quantified before, during, and after pregnancy using complementary methods: 1) spontaneous BRS (sBRS) derived from sequence method analysis of telemetric, continuous arterial pressure recordings; and 2) maximal BRS of complete sigmoidal baroreflex relationships. IS was measured (hyperinsulinemic euglycemic clamp) to determine whether BRS and IS change in parallel. sBRS was reduced at midgestation [pregnancy day 10 (P10)], returned to nonpregnant (NP) levels on P18, and fell again at late gestation (P20) (sBRS in ms/mmHg: NP, 1.66 + or - 0.04; P10, 1.17 + or - 0.11; P18, 1.55 + or - 0.12; P20, 1.31 + or - 0.05; n = 5; P < 0.05). Similar triphasic patterns were observed for both maximal BRS [in beats x min(-1) x mmHg(-1): NP, 4.45 + or - 0.52 (n = 10); P11-12, 2.76 + or - 0.11 (n = 7); P17-18, 3.79 + or - 0.14 (n = 5); P19-20, 2.32 + or - 0.40 (n = 8); P < 0.0001] and previous and current measurements of IS (in mg glucose x kg(-1) x min(-1): NP, 32 + or - 2; P19-20, 15 + or - 1; P < 0.0005). Furthermore, during pregnancy, the standard deviation (SD) of MAP increased, and the SD of HR decreased, indirectly suggesting baroreflex impairment. sBRS increased transiently during parturition, and sBRS, maximal BRS, and IS normalized 3-4 days postpartum. In conclusion, pregnancy decreases HR BRS in rats. The parallel temporal changes in BRS and IS suggest a mechanistic link.
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Affiliation(s)
- Virginia L Brooks
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, USA
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Lis CB, Suto T, Conrad K. Importance of Nitric Oxide in Control of Systemic and Renal Hemodynamics During Normal Pregnancy: Studies in the Rat and Implications for Preeclampsia. Hypertens Pregnancy 2009. [DOI: 10.3109/10641959609015699] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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McGuane JT, Debrah JE, Debrah DO, Rubin JP, Segal M, Shroff SG, Conrad KP. Role of Relaxin in Maternal Systemic and Renal Vascular Adaptations during Gestation. Ann N Y Acad Sci 2009; 1160:304-12. [DOI: 10.1111/j.1749-6632.2009.03829.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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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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Teichman SL, Unemori E, Dschietzig T, Conrad K, Voors AA, Teerlink JR, Felker GM, Metra M, Cotter G. Relaxin, a pleiotropic vasodilator for the treatment of heart failure. Heart Fail Rev 2008; 14:321-9. [PMID: 19101795 PMCID: PMC2772950 DOI: 10.1007/s10741-008-9129-3] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 11/28/2008] [Indexed: 12/22/2022]
Abstract
Relaxin is a naturally occurring peptide hormone that plays a central role in the hemodynamic and renovascular adaptive changes that occur during pregnancy. Triggering similar changes could potentially be beneficial in the treatment of patients with heart failure. The effects of relaxin include the production of nitric oxide, inhibition of endothelin, inhibition of angiotensin II, production of VEGF, and production of matrix metalloproteinases. These effects lead to systemic and renal vasodilation, increased arterial compliance, and other vascular changes. The recognition of this has led to the study of relaxin for the treatment of heart failure. An initial pilot study has shown favorable hemodynamic effects in patients with heart failure, including reduction in ventricular filling pressures and increased cardiac output. The ongoing RELAX-AHF clinical program is designed to evaluate the effects of relaxin on the symptoms and outcomes in a large group of patients admitted to hospital for acute heart failure. This review will summarize both the biology of relaxin and the data supporting its potential efficacy in human heart failure.
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Jeyabalan A, Shroff SG, Novak J, Conrad KP. The Vascular Actions of Relaxin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 612:65-87. [DOI: 10.1007/978-0-387-74672-2_6] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Sasser JM, Baylis C. The natriuretic and diuretic response to dopamine is maintained during rat pregnancy. Am J Physiol Renal Physiol 2008; 294:F1342-4. [PMID: 18400873 PMCID: PMC4356245 DOI: 10.1152/ajprenal.00067.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During pregnancy, there is a marked plasma volume expansion due to renal sodium retention. Pregnant rats exhibit a blunted response to natriuretic stimuli that signal via cGMP, and expression and activity of the cGMP phosphodiesterase PDE-5 are upregulated in the inner medullary collecting duct during pregnancy. Here, we tested the hypothesis that the natriuretic response to a cAMP agonist, dopamine, is maintained during pregnancy. Anesthetized pregnant (day 16) and age-matched virgin Sprague-Dawley rats were used to determine whether dopamine-cAMP-mediated natriuresis remains intact in pregnant rats. Blood pressure, renal clearances of inulin and p-aminohippuric acid, and excretion of sodium were measured during baseline and dopamine infusion periods. Pregnant rats had a lower blood pressure and hematocrit at baseline than their age-matched virgin counterparts. Dopamine infusion decreased blood pressure and increased glomerular filtration rate and renal plasma flow in virgin but not pregnant rats. Dopamine infusion also increased urine volume, sodium excretion, and the fractional excretion of sodium to a similar extent in virgin and pregnant rats. These results indicate that a cAMP-mediated natriuresis and diuresis (stimulated by dopamine) persists in pregnant rats.
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Affiliation(s)
- Jennifer M Sasser
- Dept. of Physiology and Functional Genomics, Univ. of Florida, PO Box 100274, Gainesville, FL 32610, USA.
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Liguori A, D'Armiento FP, Palagiano A, Balestrieri ML, Williams-Ignarro S, de Nigris F, Lerman LO, D'Amora M, Rienzo M, Fiorito C, Ignarro LJ, Palinski W, Napoli C. Effect of gestational hypercholesterolaemia on omental vasoreactivity, placental enzyme activity and transplacental passage of normal and oxidised fatty acids. BJOG 2007; 114:1547-56. [PMID: 17903226 DOI: 10.1111/j.1471-0528.2007.01510.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Maternal hypercholesterolaemia during pregnancy increases lipid peroxidation in mothers and fetuses and programs increased susceptibility to atherosclerosis later in life. The objective of this study was to elucidate the role of the placenta in mediating oxidative stress from mother to offspring. DESIGN Comparison between normo- and hypercholesterolaemic mothers (n = 36 each) and their children. SETTING Obstetric wards, hospitals of the University of Naples and Regione Campania. POPULATION Healthy primiparas delivering by caesarean section. METHODS Biochemical measurements of oxidative stress and serum leptin in cord plasma and placenta, immunochemistry of placenta microvessels, and vasoreactivity studies were performed. MAIN OUTCOME MEASURES Oxidative status (i.e. lipid composition and content of oxidised fatty acids, activity of pro- and antioxidant enzymes, immunohistochemical presence of oxidation-specific epitopes) in maternal and cord blood and in placental tissue, as well as vascular reactivity in omental arteries. RESULTS Hypercholesterolaemia during pregnancy was associated with extensive changes in fatty acid composition of both maternal and cord blood lipids, sufficient to alter vasoreactivity of omental vessels. Results also indicated that the placenta is not only subject to substantial oxidative stress, but that it may further increase fetal oxidative stress through changes of pro- and antioxidant enzyme activities. CONCLUSIONS The placenta plays an important role in both transmitting and enhancing pathogenic effects of gestational hypercholesterolaemia.
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Affiliation(s)
- A Liguori
- Regional Hospital of Pellegrini, Department of Medicine and Division of Cardiology-CCU, ASLNA1, Naples 80100, Italy
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Hladunewich M, Karumanchi SA, Lafayette R. Pathophysiology of the clinical manifestations of preeclampsia. Clin J Am Soc Nephrol 2007; 2:543-9. [PMID: 17699462 DOI: 10.2215/cjn.03761106] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Jeyabalan A, Lain KY. Anatomic and Functional Changes of the Upper Urinary Tract During Pregnancy. Urol Clin North Am 2007; 34:1-6. [PMID: 17145354 DOI: 10.1016/j.ucl.2006.10.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
An appreciation of the maternal physiologic adaptations that occur in the renal system during pregnancy is fundamental to the understanding and proper clinical management of normal pregnancy, renal disorders in the gravid patient, and pregnancy-specific conditions such as pre-eclampsia. In this article, the authors first address the anatomic changes that occur in the upper urinary tract in normal pregnancy, followed by the dramatic alterations in maternal renal hemodynamics and glomerular filtration. They also briefly discuss renal handling of various substrates in pregnancy, including protein, uric acid, and glucose. An understanding of these changes is important and relevant to the clinician caring for pregnant women.
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Affiliation(s)
- Arundhathi Jeyabalan
- Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Magee-Womens Hospital, Room 2225, 300 Halket Street, Pittsburgh, PA 15206, USA.
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