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Afsar B, Elsurer Afsar R. The dilemma of sodium intake in preeclampsia: beneficial or detrimental? Nutr Rev 2024; 82:437-449. [PMID: 37330671 DOI: 10.1093/nutrit/nuad066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023] Open
Abstract
Preeclampsia (PE) is a disorder involving de novo development of hypertension plus end organ damage after 20 weeks of gestation. PE is considered to be a heterogeneous disease. There are 2 main types of PE: early-onset (<34 weeks of gestation), which is considered to be a placental disorder and is associated with vasoconstriction, low cardiac output, and placental hypoperfusion and organ damage due to decreased microcirculation to maternal organs; and late-onset PE, which is primarily a disorder of pregnant women with obesity, diabetes, and/or cardiovascular abnormalities. In late-onset PE, there is avid sodium reabsorption by the maternal kidneys, causing hypervolemia and increased cardiac output, along with vasodilatation causing venous congestion of organs. Although PE has been a well-known disease for a long time, it is interesting to note that there is no specific sodium (salt) intake recommendation for these patients. This may be due to the fact that studies since as far back as the 1900s have shown conflicting results, and the reasons for the inconsistent findings have not been fully explained; furthermore, the type of PE in these studies was not specifically defined. Some studies suggest that sodium restriction may be detrimental in early-onset PE, but may be feasible in late-onset PE. To explore this paradox, the current review explains the hemodynamic factors involved in these 2 types of PE, summarizes the findings of the current studies, and highlights the knowledge gaps and the research needed to determine whether increase or restriction of salt or sodium intake is beneficial in different types of PE.
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Affiliation(s)
- Baris Afsar
- Department of Nephrology, Suleyman Demirel University School of Medicine, Isparta, Turkey
| | - Rengin Elsurer Afsar
- Department of Nephrology, Suleyman Demirel University School of Medicine, Isparta, Turkey
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Rojas D, Abad C, Piñero S, Medina Y, Chiarello DI, Proverbio F, Marín R. Effect of Mg-Gluconate on the Osmotic Fragility of Red Blood Cells, Lipid Peroxidation, and Ca2+-ATPase (PMCA) Activity of Placental Homogenates and Red Blood Cell Ghosts From Salt-Loaded Pregnant Rats. Front Physiol 2022; 13:794572. [PMID: 35153828 PMCID: PMC8829449 DOI: 10.3389/fphys.2022.794572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/05/2022] [Indexed: 01/12/2023] Open
Abstract
Preeclampsia (PE) is a pregnancy-specific syndrome with multisystem involvement which leads to fetal, neonatal, and maternal morbidity and mortality. A model of salt-loaded pregnant rats has been previously studied, sharing several pathological characteristics of preeclamptic women. In this study, it was compared the effects of the treatment with an oral magnesium salt, magnesium gluconate (Mg-gluconate), on the osmotic fragility of red blood cells, lipid peroxidation, and PMCA activity of placental homogenates and red blood cell ghosts in salt-loaded pregnant rats. Mg-gluconate has a higher antioxidant capacity than MgSO4 due to the presence of several hydroxyl groups in the two anions of this salt. Salt-loaded pregnant rats received 1.8% NaCl solution ad libitum as a beverage during the last week of pregnancy. On day 22nd of pregnancy, the rats were euthanized and red blood cells and placenta were obtained. Salt-loaded pregnant rats showed an increased level of lipid peroxidation and a lowered PMCA activity in placental and red blood cell ghosts, as well as an increased osmotic fragility of their red blood cells. The treatment of the salt-loaded pregnant rats with Mg-gluconate avoids the rise in the level of lipid peroxidation and the concomitant lowering of the PMCA activity of their red blood cell membranes, reaching values similar to those from control pregnant rats. Also, this treatment prevents the increase of the osmotic fragility of their red blood cells, keeping values similar to those from control pregnant rats. Mg-gluconate seems to be an important candidate for the replacement of the MgSO4 treatment of preeclamptic women.
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Agalakova NI, Reznik VA, Nadei OV, Ershov IA, Rassokha OS, Vasyutina ML, Ivanov DO, Adair CD, Galagudza MM, Bagrov AY. Antibody against Na/K-ATPase Inhibitor Lowers Blood Pressure and Increases Vascular Fli1 in Experimental Preeclampsia. Am J Hypertens 2020; 33:514-519. [PMID: 31713584 DOI: 10.1093/ajh/hpz180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/21/2019] [Accepted: 11/09/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Previous studies implicated cardiotonic steroids, including Na/K-ATPase inhibitor marinobufagenin (MBG), in the pathogenesis of preeclampsia (PE). We demonstrated that MBG induces fibrosis via mechanism involving inhibition of Fli1, a nuclear transcription factor and a negative regulator of collagen-1 synthesis. We hypothesized that PE blockade of increased MBG with antibody would lessen the fibrosis of umbilical arteries and lower the blood pressure in rats with PE. METHODS We tested 36 pregnant Sprague-Dawley rats in which 12 were made hypertensive by 1.8% Na supplementation (days 6-19 of gestation), 12 pregnant rats served controls. At day 19, PE rats received one intraperitoneal injection of polyclonal anti-MBG-4 antibody (0.5 ug/ml) for 4 hours. RESULTS PE was associated with higher blood pressure (117 ± 2 vs. 107 ± 2 mm Hg; P < 0.01), plasma MBG levels (1.54 ± 0.34 vs. 0.49 ± 0.11 nmol/L; P < 0.01), protein excretion (26 vs. 12 mg/24 hours), sFlt-1 (3-fold), decrease in Fli1 (7-fold) and increase in collagen-1 in aorta (4-fold) vs. control rats (all P < 0.01). In 12 rats treated with polyclonal anti-MBG-4 antibody blood pressure dropped (93 ± 3 mm Hg) and Fli1 was decreased much less (2-fold; P < 0.01 vs. nontreated rats). CONCLUSIONS These results demonstrate that in experimental PE elevated MBG level is implicated in umbilical fibrosis via suppression of Fli1.
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Affiliation(s)
- Natalia I Agalakova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Vitaly A Reznik
- Department of Obstetrics and Gynecology, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
| | - Olga V Nadei
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Ivan A Ershov
- Department of Obstetrics and Gynecology, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
| | - Olga S Rassokha
- Department of Obstetrics and Gynecology, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
| | - Marina L Vasyutina
- Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia
| | - Dmitry O Ivanov
- Department of Obstetrics and Gynecology, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
| | - C David Adair
- Department of Obstetrics and Gynecology, University of Tennessee, Chattanooga, Tennessee, USA
| | - Michael M Galagudza
- Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia
| | - Alexei Y Bagrov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
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Gatford KL, Andraweera PH, Roberts CT, Care AS. Animal Models of Preeclampsia: Causes, Consequences, and Interventions. Hypertension 2020; 75:1363-1381. [PMID: 32248704 DOI: 10.1161/hypertensionaha.119.14598] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Preeclampsia is a common pregnancy complication, affecting 2% to 8% of pregnancies worldwide, and is an important cause of both maternal and fetal morbidity and mortality. Importantly, although aspirin and calcium are able to prevent preeclampsia in some women, there is no cure apart from delivery of the placenta and fetus, often necessitating iatrogenic preterm birth. Preclinical models of preeclampsia are widely used to investigate the causes and consequences of preeclampsia and to evaluate safety and efficacy of potential preventative and therapeutic interventions. In this review, we provide a summary of the published preclinical models of preeclampsia that meet human diagnostic criteria, including the development of maternal hypertension, together with new-onset proteinuria, maternal organ dysfunction, and uteroplacental dysfunction. We then discuss evidence from preclinical models for multiple causal factors of preeclampsia, including those implicated in early-onset and late-onset preeclampsia. Next, we discuss the impact of exposure to a preeclampsia-like environment for later maternal and progeny health. The presence of long-term impairment, particularly cardiovascular outcomes, in mothers and progeny after an experimentally induced preeclampsia-like pregnancy, implies that later onset or reduced severity of preeclampsia will improve later maternal and progeny health. Finally, we summarize published intervention studies in preclinical models and identify gaps in knowledge that we consider should be targets for future research.
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Affiliation(s)
- Kathryn L Gatford
- From the Adelaide Medical School and Robinson Research Institute, The University of Adelaide, Australia
| | - Prabha H Andraweera
- From the Adelaide Medical School and Robinson Research Institute, The University of Adelaide, Australia
| | - Claire T Roberts
- From the Adelaide Medical School and Robinson Research Institute, The University of Adelaide, Australia
| | - Alison S Care
- From the Adelaide Medical School and Robinson Research Institute, The University of Adelaide, Australia
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Eisele N, Klossner R, Escher G, Rudloff S, Larionov A, Theilig F, Mohaupt MG, Mistry HD, Gennari‐Moser C. Physiological and Molecular Responses to Altered Sodium Intake in Rat Pregnancy. J Am Heart Assoc 2018; 7:e008363. [PMID: 30371243 PMCID: PMC6201473 DOI: 10.1161/jaha.117.008363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 06/07/2018] [Indexed: 11/21/2022]
Abstract
Background In pregnancy, a high plasma volume maintains uteroplacental perfusion and prevents placental ischemia, a condition linked to elevated maternal blood pressure ( BP ). Reducing BP by increasing Na+ intake via plasma volume expansion appears contra-intuitive. We hypothesize that an appropriate Na+ intake in pregnancy reduces maternal BP and adapts the renin-angiotensin system in a pregnancy-specific manner. Methods and Results BP was measured by implanted telemetry in Sprague-Dawley rats before and throughout pregnancy. Pregnant and nonpregnant animals received either a normal-salt (0.4%; NS ), high-salt (8%; HS ), or low-salt (0.01%; LS ) diet, or HS (days 1-14) followed by LS (days 14-20) diet ( HS / LS ). Before delivery (day 20), animals were euthanized and organs collected. Food, water, and Na+ intake were monitored in metabolic cages, and urinary creatinine and Na+ were analyzed. Na+ intake and retention increased in pregnancy ( NS , LS ), leading to a positive Na+ balance ( NS , LS ). BP was stable during LS , but reduced in HS conditions in pregnancy. The renin-angiotensin system was adapted as expected. Activating cleavage of α- and γ-subunits of the renal epithelial Na+ channel and expression of-full length medullary β-subunits, accentuated further in all LS conditions, were upregulated in pregnancy. Conclusions Pregnancy led to Na+ retention adapted to dietary changes. HS exposure paradoxically reduced BP . Na+ uptake while only modestly linked to the renin-angiotensin system is enhanced in the presence of posttranslational renal epithelial Na+ channel modifications. This suggests (1) storage of Na+ in pregnancy upon HS exposure, bridging periods of LS availability; and (2) that potentially non-renin-angiotensin-related mechanisms participate in EN aC activation and consecutive Na+ retention.
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Affiliation(s)
- Nicole Eisele
- Department of Nephrology and HypertensionUniversity of BernSwitzerland
- Department of BioMedical ResearchUniversity of BernSwitzerland
| | - Rahel Klossner
- Department of BioMedical ResearchUniversity of BernSwitzerland
- Teaching Hospital Internal Medicine LindenhofgruppeBerneSwitzerland
| | - Geneviève Escher
- Department of Nephrology and HypertensionUniversity of BernSwitzerland
- Department of BioMedical ResearchUniversity of BernSwitzerland
| | - Stefan Rudloff
- Department of Nephrology and HypertensionUniversity of BernSwitzerland
- Department of BioMedical ResearchUniversity of BernSwitzerland
| | - Alexey Larionov
- Division of Internal MedicineUniversity of FribourgSwitzerland
| | | | - Markus G. Mohaupt
- Department of BioMedical ResearchUniversity of BernSwitzerland
- Teaching Hospital Internal Medicine LindenhofgruppeBerneSwitzerland
| | - Hiten D. Mistry
- Department of BioMedical ResearchUniversity of BernSwitzerland
- Division of Child Health, Obstetrics and GynaecologySchool of MedicineCity Hospital NottinghamNottinghamUnited Kingdom
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Tyurenkov IN, Perfilova VN, Smirnov AV, Reznikova LB, Poroyskaya AV, Verovsky VE. Features of endothelial dysfunction and morphofunctional changes of the uteroplacental complex in experimentally induced pre-eclampsia. Pregnancy Hypertens 2016; 6:423-430. [PMID: 27939494 DOI: 10.1016/j.preghy.2016.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 10/28/2016] [Accepted: 11/02/2016] [Indexed: 11/24/2022]
Abstract
BACKGROUND Pre-eclampsia is considered to be a severe complication of pregnancy. Theoretical investigation of its etiology and pathogenesis, development of strategies for its prevention and treatment are conditioned by the development of appropriate experimental models of this pathology. METHODS The study involved Wistar rat lines weighing 220-240g. Experimental pre-eclampsia was modeled by replacing drinking water consumed by pregnant female rats with 1.8% NaCl solution throughout gestation. Arterial pressure, protein concentration in urine and tissue hydration extent were measured on the 1st and 21st days of gestation. Uteroplacental blood flow, vasodilating and antithrombotic endothelial functions were also assessed. For pathomorphological and immunohistochemical investigation murine monoclonal antibodies against vascular endothelial growth factor (VEGF), polyclonal rabbit antibodies against inducible and endothelial NO-synthases were used. RESULTS Replacing drinking water with 1.8% NaCl solution in female rats throughout gestation elevates arterial pressure, causes proteinuria and edema, impairs vasodilating and antithrombotic endothelial properties, and suppresses uteroplacental blood circulation. A morphological examination of the animals revealed the signs of focal duodenitis, spasms of myometrium arteries with no invasion of syncytiotrophoblast into its walls which also involved a raised VEGF and reduced eNOS expression in the endothelium of myometrial vessels, as well as cytoplasmic expression of iNOS in the cells of inflammatory infiltrate. CONCLUSIONS These findings make it possible to conclude that replacing drinking water with 1.8% NaCl solution causes a number of changes typical of pre-eclampsia and, therefore, can be regarded as an experimental model of this pathologic condition.
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Affiliation(s)
- I N Tyurenkov
- Department of Pharmacology and Biopharmacy of the Department for Refresher Training, Volgograd State Medical University, 400001 Volgograd, Russia
| | - V N Perfilova
- Department of Pharmacology and Biopharmacy of the Department for Refresher Training, Volgograd State Medical University, 400001 Volgograd, Russia.
| | - A V Smirnov
- Department of Pathological Anatomy, Volgograd State Medical University, Volgograd, Russia
| | - L B Reznikova
- Department of Pharmacology and Biopharmacy of the Department for Refresher Training, Volgograd State Medical University, 400001 Volgograd, Russia
| | - A V Poroyskaya
- Department of Pharmacology and Biopharmacy of the Department for Refresher Training, Volgograd State Medical University, 400001 Volgograd, Russia
| | - V E Verovsky
- Department of Theoretical Biochemistry with a Course of Clinical Biochemistry, Volgograd State Medical University, Volgograd, Russia
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Yılmaz ZV, Akkaş E, Türkmen GG, Kara Ö, Yücel A, Uygur D. Dietary sodium and potassium intake were associated with hypertension, kidney damage and adverse perinatal outcome in pregnant women with preeclampsia. Hypertens Pregnancy 2016; 36:77-83. [DOI: 10.1080/10641955.2016.1239734] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Zehra Vural Yılmaz
- Zekai Tahir Burak Women’s Health Education and Training Hospital, Department of Perinatology, Ankara, Turkey
| | - Elif Akkaş
- Dr. Sami Ulus Women’s and Children’s Health Training and Research Hospital, Department of Obstetrics and Gynaecology, Ankara, Turkey
| | | | - Özgür Kara
- Zekai Tahir Burak Women’s Health Education and Training Hospital, Department of Perinatology, Ankara, Turkey
| | - Aykan Yücel
- Zekai Tahir Burak Women’s Health Education and Training Hospital, Department of Perinatology, Ankara, Turkey
| | - Dilek Uygur
- Zekai Tahir Burak Women’s Health Education and Training Hospital, Department of Perinatology, Ankara, Turkey
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Nagel C, Trenk L, Aurich J, Wulf M, Aurich C. Changes in blood pressure, heart rate, and blood profile in mares during the last 3 months of gestation and the peripartum period. Theriogenology 2016; 86:1856-64. [PMID: 27393220 DOI: 10.1016/j.theriogenology.2016.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/01/2016] [Accepted: 06/03/2016] [Indexed: 10/21/2022]
Abstract
In this study, peripartum changes in complete blood count, plasma electrolyte concentrations, blood pressure, heart rate, and heart rate variability (HRV) were determined in pregnant Warmblood mares (n = 10). Blood was collected from Days 245 to 330 of gestation (phase A), 2Days 3 to 1 before foaling (phase B), repeatedly within 12 hours after foaling (phase C), and on Days 1 to 3 postpartum (phase D). On the same days as blood collection, blood pressure and cardiac beat-to-beat intervals were measured and time domain HRV variables were calculated. Blood pressure decreased during the past 3 months of gestation, reached a nadir at foaling and increased rapidly thereafter (P < 0.001). Heart rate increased in phase A, reached a maximum in phase B, and decreased directly after foaling (P < 0.001) while HRV increased transiently after foaling (P < 0.001). The number of polymorphonuclear granulocytes was higher during phases B, C, and D than that during phase A (P < 0.001) and total leukocyte numbers peaked in phase C (P < 0.001). Erythrocyte counts and hematocrit increased immediately after foaling with a rapid decrease thereafter (P < 0.001), while plasma total protein was highest 1 hour after foaling (P < 0.001). Sodium and chloride concentrations increased from phases A to C and decreased in phase D (P < 0.001). Calcium concentrations were lowest immediately after foaling. In conclusion, changes in cardiovascular function and a transient hemoconcentration occur in peripartum mares. These changes may favor adequate uterine perfusion.
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Affiliation(s)
- Christina Nagel
- Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, Neustadt/Dosse, Germany.
| | - Lisa Trenk
- Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria
| | - Jörg Aurich
- Section for Obstetrics, Gynecology and Andrology, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria
| | - Manuela Wulf
- Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, Neustadt/Dosse, Germany
| | - Christine Aurich
- Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria
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Pai CH, Yen CT, Chen CP, Yu IS, Lin SW, Lin SR. Lack of Thromboxane Synthase Prevents Hypertension and Fetal Growth Restriction after High Salt Treatment during Pregnancy. PLoS One 2016; 11:e0151617. [PMID: 26974824 PMCID: PMC4790927 DOI: 10.1371/journal.pone.0151617] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/29/2016] [Indexed: 11/29/2022] Open
Abstract
Preeclampsia (PE) is a potentially fatal pregnancy-related hypertensive disorder characterized by poor placenta development that can cause fetal growth restriction. PE-associated pathologies, including thrombosis, hypertension, and impaired placental development, may result from imbalances between thromboxane A2 (TXA2) and prostacyclin. Low-dose aspirin, which selectively inhibits TXA2 production, is used to prevent high-risk PE. However, the role of TXA2 in aspirin-mediated protective effects in women with PE is not understood fully. In this study, we examined the role of prostanoids in PE using human samples and an induced PE mouse model. We demonstrated that the administration of salted drinking water (2.7% NaCl) to wild-type mice resulted in elevated placental TXA2 synthase (TXAS) and plasma TXA2, but not prostacyclin, levels, which was also found in our clinical PE placenta samples. The high salt-treated wild-type pregnant mice had shown unchanged maternal body weight, hypertension (MAP increase 15 mmHg), and decreased pup weight (~50%) and size (~24%), but these adverse effects were ameliorated in TXAS knockout (KO) mice. Moreover, increased expression of interleukin-1β and downstream phosphorylated-p38-mitogen-activated protein kinase were concordant with apoptosis induction in the placentas of salt water-treated wild-type mice. These alterations were not observed in TXAS KO mice. Together, our data suggest that TXA2 depletion has anti-PE effects due to the prevention of hypertension and placental damage through downregulation of the interleukin-1β pathway.
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Affiliation(s)
- Chen-Hsueh Pai
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ching-Tzu Yen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan
| | - Chie-Pein Chen
- Division of High Risk Pregnancy, Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan
| | - I-Shing Yu
- Laboratory Animal Center, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shu-Wha Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail: (SRL); (SWL)
| | - Shu-Rung Lin
- Department of Bioscience Technology, College of Science, Chung-Yuan Christian University, Taoyuan, Taiwan
- Center for Nanotechnology and Center for Biomedical Technology, Chung-Yuan Christian University, Taoyuan, Taiwan
- * E-mail: (SRL); (SWL)
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Rojas D, Rodríguez F, Barráez J, Piñero S, Chiarello DI, Abad C, Marín R, Proverbio F. Osmotic fragility of red blood cells, lipid peroxidation and Ca²⁺-ATPase activity of placental homogenates and red blood cell ghosts in salt-loaded pregnant rats. J Matern Fetal Neonatal Med 2015; 29:229-33. [PMID: 25682780 DOI: 10.3109/14767058.2014.994499] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To evaluate the osmotic fragility of red blood cells and the level of lipid peroxidation, the Ca(2+)-ATPase activity of red cell ghosts and placental homogenates from salt-loaded pregnant rats. METHODS Salt-loaded pregnant rats received 1.8% NaCl solution ad libitum as a beverage for seven days, starting on 15th day of pregnancy. Then, it was evaluated the level of lipid peroxidation and the Ca(2+)-ATPase activity of placental homogenates and red blood cell ghosts from control and experimental rats. Furthermore, the osmotic fragility of the red blood cells was evaluated by measuring the lysis of these cells when incubated with a NaCl solution with different osmolarities. RESULTS It was found that placental homogenates and red blood cell ghosts from experimental pregnant rats showed an increased level of lipid peroxidation and a lowered Ca(2+)-ATPase activity, as compared to control pregnant rats. They also presented an increased osmotic fragility of their red blood cells. CONCLUSIONS Salt-loaded pregnant rats showed, similar to preeclamptic women, an increased level of lipid peroxidation and a lowered Ca(2+)-ATPase activity in placental and red blood cells membranes, as well as an increased osmotic fragility of the red blood cells.
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Affiliation(s)
- Deliana Rojas
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
| | - Freddy Rodríguez
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
| | - Juvell Barráez
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
| | - Sandy Piñero
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
| | - Delia I Chiarello
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
| | - Cilia Abad
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
| | - Reinaldo Marín
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
| | - Fulgencio Proverbio
- a Laboratorio de Bioenergética Celular , Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas , Venezuela
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Effect of GABA derivatives on the rate of thrombus formation, platelet aggregation, and plasma coagulation capacity in rats with experimental gestosis. Bull Exp Biol Med 2014; 158:219-21. [PMID: 25432276 DOI: 10.1007/s10517-014-2726-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Indexed: 10/24/2022]
Abstract
Experimental gestosis induced by replacement of drinking water with 1.8% NaCl promoted hypercoagulation, increased the rate and degree of platelet aggregation, and reduced clotting time in pregnant females. GABA derivatives, compounds RGPU-151, RGPU-152, and phenibut normalized parameters of hemostasis and platelet aggregation and the rate of thrombus formation in the animals. The efficiency of the test substances did not significantly differ from that of the reference drug sulodexide.
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Ex vivo endothelin dependent contraction of the remodeled rat spiral artery. Placenta 2014; 35:702-8. [PMID: 25064069 DOI: 10.1016/j.placenta.2014.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 06/25/2014] [Accepted: 07/04/2014] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Similarities of the rat to the human placenta make rat pregnancy models relevant to the study of human gestational diseases. Understanding of species differences is necessary to extrapolate from animal models to humans. We observed alpha-smooth muscle actin (αSMA) expression in rat endovascular trophoblasts (EVasT) and investigated the spatial and temporal expression of smooth muscle (SM) proteins and their potential function in remodeled spiral artery. METHODS Rat placentas were examined from gestational day 13 to term, and were immunostained for cytokeratin, αSMA, alpha heavy chain of SM myosin, non-muscle myosin, Rho proteins, regulators of SM gene expression, myocardin, an early marker of SM differentiation and endothelin receptors A and B (ETA, ETB). Transmission electron microscopy (TEM) was performed. Modified spiral artery rings were studied ex vivo for endothelin-1- induced contraction. RESULTS EVasT expressed SM proteins co-localizing with cytokeratin confirming their trophoblastic origin from gestational day 13 to term. Thin fibers, consistent with actin fibers, were observed by TEM, in the cellular localization of αSMA in EVasT. Functional experiments revealed that addition of 10(-7) M endothelin-1 ex vivo reduced vascular lumen area by 11.1% ± 1.8% compared with control. This effect was reduced to only 1.0 ± 1.7% with ETA antagonist, and to 5.4 ± 1.7% contraction by ETB antagonist, p < 0.002, for all. DISCUSSION The expression of SM proteins in EVasT along with the contractibility of the rat remodeled spiral artery ex vivo, suggest that some vascular tone is potentially maintained by endothelin-1, and may play a role in situations of dysregulation of the vasoactive systems.
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GABA derivatives citrocard and salifen reduce the intensity of experimental gestosis. Bull Exp Biol Med 2014; 157:42-4. [PMID: 24913573 DOI: 10.1007/s10517-014-2487-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Indexed: 10/25/2022]
Abstract
Substitution of drinking water with 1.8 % NaCl solution in pregnant female rats from day 1 of gestation until parturitions was followed by the development of experimental gestosis. Gestosis manifested in an increase in BP by 18.2 %, protein concentration in the urine by 6.2 times, and edema severity in muscles, brain, and omentum in comparison with the initial level. The concentration of homocysteine in blood plasma of rats with complicated pregnancy 4.4-fold surpassed that in pregnant rats without gestosis, which can probably in a cause for gestosis development. GABA derivatives citrocard (50 mg/kg) and salifen (15 mg/kg), and the reference substance sulodexide (30 U/kg) reduced the severity of gestosis manifestations, which was seen from the absence of BP rise, decrease in urinary protein concentration by 1.9, 2.0, and 1.3 times and blood level of homocysteine by 1.7, 1.5, and 2.6 times, respectively, and a decrease in edema degree in comparison with female rats with experimental gestosis receiving physiological saline.
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Shin JA, Ahn YM, Lee HA, Park H, Kim YJ, Lee HY. Effect of maternal excessive sodium intake on postnatal brain development in rat offspring. Nutr Neurosci 2014; 18:118-24. [PMID: 24621066 DOI: 10.1179/1476830513y.0000000102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Postnatal brain development is affected by the in utero environment. Modern people usually have a high sodium intake. The aim of this study was to investigate the effect of sodium hyperingestion during pregnancy on the postnatal brain development of rat offspring. METHODS The sodium-overloaded rats received 1.8% NaCl in their drinking water for 7 days during the last week of gestation. Their body weight, urine, and blood levels of sodium and other parameters were measured. Some rats were sacrificed at pregnancy day 22 and the weight and length of the placenta and foetus were measured. The cerebral cortex and hippocampus were obtained from their offspring at postnatal day 1 and at postnatal weeks 1, 2, 4, and 8. Western blot analyses were conducted with brain tissue lysates. RESULTS The sodium-overloaded animals had decreased weight gain in the last week of gestation as well as decreased food intake, increased water intake, urine volume, urine sodium, and serum sodium. There were no differences in placental weight and length. The foetuses of sodium-overloaded rats showed decreased body weight and size, and this difference was maintained postnatally for 2 weeks. In the cerebral cortex and hippocampus of the offspring, the protein levels of myelin basic protein, calmodulin/calcium-dependent protein kinase II, and brain-derived neurotrophic factor were decreased or aberrantly expressed. DISCUSSION The present data suggest that increased sodium intake during pregnancy affects the brain development of the offspring.
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Paixão AD, Alexander BT. How the kidney is impacted by the perinatal maternal environment to develop hypertension. Biol Reprod 2013; 89:144. [PMID: 24227755 DOI: 10.1095/biolreprod.113.111823] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Environmental conditions during perinatal development such as maternal undernutrition, maternal glucocorticoids, placental insufficiency, and maternal sodium overload can program changes in renal Na(+) excretion leading to hypertension. Experimental studies indicate that fetal exposure to an adverse maternal environment may reduce glomerular filtration rate by decreasing the surface area of the glomerular capillaries. Moreover, fetal responses to environmental insults during early life that contribute to the development of hypertension may include increased expression of tubular apical or basolateral membrane Na(+) transporters and increased production of renal superoxide leading to enhanced Na(+) reabsorption. This review will address the role of these potential renal mechanisms in the fetal programming of hypertension in experimental models induced by maternal undernutrition, fetal exposure to glucocorticoids, placental insufficiency, and maternal sodium overload in the rat.
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Affiliation(s)
- Ana D Paixão
- Department of Physiology and Pharmacology, Center of Biological Sciences, Federal University of Pernambuco, Recife, Brazil
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Tyurenkov IN, Perfilova VN, Popova TA, Ivanova LB, Prokofiev II, Gulyaeva OV, Stepa LI. Changes in Oxidant and Antioxidant Status of Females with Experimental Gestosis under the Effect of GABA Derivatives. Bull Exp Biol Med 2013; 155:363-5. [DOI: 10.1007/s10517-013-2154-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Elzwiei F, Bassien-Capsa V, St-Louis J, Chorvatova A. Regulation of the sodium pump during cardiomyocyte adaptation to pregnancy. Exp Physiol 2012; 98:183-92. [PMID: 22848078 DOI: 10.1113/expphysiol.2012.066282] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Regulation of the sodium pump during normal pregnancy and its effect on the function of cardiomyocytes is poorly understood. Our objective was to evaluate the possible implication of the Na(+)-K(+)-ATPase, the sodium pump which controls cellular ionic and metabolic homeostasis, in the adaptations of cardiomyocytes to normal pregnancy. We have used Western blots and patch-clamp measurements to identify changes in the sodium pump proteins. Confocal microscopy was applied to estimate intracellular sodium concentration. Time-resolved spectroscopy was employed to measure mitochondrial NAD(P)H fluorescence and estimate oxidative metabolic state. Optical microscopy was adopted to study the contractility responses of cardiomyocytes. Cells from non-pregnant and pregnant rats (1 day prior parturition) were studied. Our results showed lower protein expression of the α1 Na(+)-K(+)-ATPase isoform in cardiomyocytes in pregnant rats, decreased sodium pump membrane current and elevated steady-state sodium concentration. In addition, ouabain, the inhibitor of the sodium pump capable of increasing cardiomyocyte contractility in non-pregnant rats in a concentration-dependent manner, failed to affect cell contractions in pregnant rats. We also noted modified responsiveness of the mitochondrial metabolic state to ouabain in cardiac cells. The gathered data confirmed that in pregnant rats, the sodium pump protein content and transmembrane flux are decreased, while the sensitivity of cardiomyocyte contractility and the sensitivity of mitochondrial metabolic redox state to ouabain are modified, pointing to regulation of the Na(+)-K(+)-ATPase during cardiac cell adaptations to normal pregnancy.
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Affiliation(s)
- F Elzwiei
- CHU Sainte Justine, Research Centre, Montreal, Quebec, Canada H3T 1C5
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Fedorova L, Gatto-Weis C, Smaili S, Khurshid N, Shapiro JI, Malhotra D, Horrigan T. Down-regulation of the transcription factor snail in the placentas of patients with preeclampsia and in a rat model of preeclampsia. Reprod Biol Endocrinol 2012; 10:15. [PMID: 22360878 PMCID: PMC3298516 DOI: 10.1186/1477-7827-10-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 02/23/2012] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Placental malfunction in preeclampsia is believed to be a consequence of aberrant differentiation of trophoblast lineages and changes in utero-placental oxygenation. The transcription factor Snail, a master regulator molecule of epithelial-mesenchymal transition in embryonic development and in cancer, is shown to be involved in trophoblast differentiation as well. Moreover, Snail can be controlled by oxidative stress and hypoxia. Therefore, we examined the expression of Snail and its downstream target, e-cadherin, in human normal term, preterm and preeclamptic placentas, and in pregnant rats that developed preeclampsia-like symptoms in the response to a 20-fold increase in sodium intake. METHODS Western blotting analysis was used for comparative expression of Snail and e- cadherin in total protein extracts. Placental cells expressing Snail and e-cadherin were identified by immunohistochemical double-labeling technique. RESULTS The levels of Snail protein were decreased in human preeclamptic placentas by 30% (p < 0.01) compared to normal term, and in the rat model by 40% (p < 0.001) compared to control placentas. In preterm placentas, the levels of Snail expression varied, yet there was a strong trend toward statistical significance between preterm and preeclamptic placentas. In humans, e-cadherin protein level was 30% higher in preeclamptic (p < 0.05) placentas and similarly, but not significantly (p = 0.1), high in the preterm placentas compared to normal term. In the rat model of preeclampsia, e-cadherin was increased by 60% (p < 0.01). Immunohistochemical examination of human placentas demonstrated Snail-positive staining in the nuclei of the villous trophoblasts and mesenchymal cells and in the invasive trophoblasts of the decidua. In the rat placenta, the majority of Snail positive cells were spongiotrophoblasts of the junctional zone, while in the labyrinth, Snail-positive sinusoidal giant trophoblasts cells were found in some focal areas located close to the junctional zone. CONCLUSION We demonstrated that human preeclampsia and the salt-induced rat model of preeclampsia are associated with the reduced levels of Snail protein in placenta. Down-regulation of the transcription factor Snail in placental progenitor cell lineages, either by intrinsic defects and/or by extrinsic and maternal factors, may affect normal placenta development and function and thus contribute to the pathology of preeclampsia.
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Affiliation(s)
- Larisa Fedorova
- Department of Medicine, University of Toledo School of Medicine, Toledo, OH 43614, USA
| | - Cara Gatto-Weis
- Department of Pathology, University of Toledo School of Medicine, Toledo, OH 43614, USA
| | - Sleiman Smaili
- Department of Obstetrics and Gynecology, University of Toledo School of Medicine, Toledo, OH 43614, USA
| | - Nauman Khurshid
- Department of Obstetrics and Gynecology, University of Toledo School of Medicine, Toledo, OH 43614, USA
| | - Joseph I Shapiro
- Department of Medicine, University of Toledo School of Medicine, Toledo, OH 43614, USA
| | - Deepak Malhotra
- Department of Medicine, University of Toledo School of Medicine, Toledo, OH 43614, USA
| | - Terrence Horrigan
- Department of Obstetrics and Gynecology, University of Toledo School of Medicine, Toledo, OH 43614, USA
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Provencher M, Houde V, Brochu M, St-Louis J. Mineralocorticoids participate in the reduced vascular reactivity of pregnant rats. Am J Physiol Heart Circ Physiol 2011; 302:H1195-201. [PMID: 22198172 DOI: 10.1152/ajpheart.00510.2011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The renin-angiotensin-aldosterone (RAA) system is markedly activated in pregnancy. We evaluated if mineralocorticoid receptors (MR), a major component of the RAA system, are involved in the reduced vascular reactivity associated with pregnancy. Canrenoate (MR antagonist; 20 mg·kg(-1)·day(-1)) was administered to nonpregnant (NP) rats for 7 days and to pregnant rats from day 15 to 22 of gestation. These were killed on day 17, 19, or 22 of gestation and, for NP rats, after 7 days treatment. Constrictor responses to phenylephrine (PhE) and KCl were measured in endothelium-denuded thoracic aortic rings under the influence of modulators of potassium (activators) and calcium (blocker) channels. Responses to the constrictors were blunted from days 17 to 22 of gestation. Although canrenoate increased responses to PhE and KCl, it did not reverse their blunted responses in gestation. NS-1619 and cromakalim (respectively, high-conductance calcium-activated potassium channels and ATP-sensitive potassium channel activators) diminished responses to both PhE and KCl. Inhibition by NS-1619 on responses to both agonists was decreased under canrenoate treatment in NP, but the reduced influence of NS-1619 during gestation was reversed by the mineralocorticoid antagonist. Cromakalim reduced the response to PhE significantly in the pregnant groups; this effect was enhanced by canrenoate. Finally, nifedipine (calcium channel blocker) markedly reduced KCl responses but to a lesser extent at the end of pregnancy, an inhibiting effect that was increased with canrenoate treatment. These data demonstrate that treating rats with a MR antagonist increased vascular reactivity but that it differentially affected potassium and calcium channel activity in aortas of NP and pregnant animals. This suggests that aldosterone is one of the components involved in vascular adaptations to pregnancy.
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Affiliation(s)
- M Provencher
- Research Centre, CHU Sainte-Justine and Departments of Obstetrics-Gynecology, Université de Montréal, Montréal, Québec, Canada
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Michałek K, Jankowiak D, Ożgo M, Skrzypczak W. Renal regulation of sodium, potassium and chloride balance in single- and twin-pregnant goats. Acta Vet Hung 2010; 58:199-209. [PMID: 20460219 DOI: 10.1556/avet.58.2010.2.6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of these studies was to analyse and compare changes in selected parameters of renal function in terms of water-electrolyte balance regulation in single- and twin-pregnant goats. Clearance analyses were carried out on 16 pregnant White Improved goats (8 in single and 8 in twin gestation). Blood plasma and urine samples were analysed for the concentration of inulin, endogenous creatinine, sodium, potassium, and chlorides. It has been demonstrated that glomerular filtration rate (GFR) in the goat kidney does not change significantly during gestation. GFR recorded from the 1st week until the 20th week of gestation in twin-pregnant goats was only slightly higher compared to those observed in single-pregnant does. Blood plasma concentrations of major electrolytes, i.e. sodium, potassium and chloride ions, did not differ significantly in pregnant and non-pregnant goats, and remained within the reference values. From the very beginning of gestation, the single-pregnant goats showed increased renal potassium clearance; however, the level of sodium clearance remained stable. On the other hand, sodium clearance increased from the 2nd month of gestation in the twin-pregnant goats, while the load of excreted potassium did not change. These changes had probably resulted from varied levels of aldosterone and progesterone and their mutual proportions differing between the groups.
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Affiliation(s)
- Katarzyna Michałek
- 1 West Pomeranian University of Technology in Szczecin Department of Animal Physiology and Cytobiology Dr Judyma 6 71-466 Szczecin Poland
| | - Dorota Jankowiak
- 1 West Pomeranian University of Technology in Szczecin Department of Animal Physiology and Cytobiology Dr Judyma 6 71-466 Szczecin Poland
| | - Małgorzata Ożgo
- 1 West Pomeranian University of Technology in Szczecin Department of Animal Physiology and Cytobiology Dr Judyma 6 71-466 Szczecin Poland
| | - Wiesław Skrzypczak
- 1 West Pomeranian University of Technology in Szczecin Department of Animal Physiology and Cytobiology Dr Judyma 6 71-466 Szczecin Poland
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Cardoso HD, Cabral EV, Vieira-Filho LD, Vieyra A, Paixão ADO. Fetal development and renal function in adult rats prenatally subjected to sodium overload. Pediatr Nephrol 2009; 24:1959-65. [PMID: 19603192 DOI: 10.1007/s00467-009-1247-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 05/14/2009] [Accepted: 06/08/2009] [Indexed: 11/28/2022]
Abstract
The aims of this study were (1) to evaluate two factors that affect fetal development--placental oxidative stress (Ox) and plasma volume (PV)--in dams with sodium overload and (2) to correlate possible alterations in these factors with subsequent modifications in the renal function of adult offspring. Wistar dams were maintained on 0.17 M NaCl instead of water from 20 days before mating until either the twentieth pregnancy day/parturition or weaning. Colorimetric methods were used to measure Ox in maternal and offspring tissues, PV, 24-h urinary protein (U(Prot24 h)) and serum triacylglycerols (TG) and cholesterol (Chol). Renal hemodynamics was evaluated in the offspring at 90 days of age using a blood pressure transducer, a flow probe and inulin clearance to measure mean arterial pressure (MAP), renal blood flow and glomerular filtration rate (GFR), respectively. The number of nephrons (NN) was counted in kidney suspensions. Dams showed unchanged PV, placental Ox and fetal weight but increased U(Prot24 h) (150%, P < 0.05). Prenatally sodium-overloaded pups showed increased U(Prot24 h) (45%, P < 0.05) but unchanged MAP, renal hemodynamics, NN and kidney Ox. Prenatally and postnatally sodium-overloaded rats showed increased U(Prot24 h) (27%, P < 0.05) and kidney Ox (44%, P < 0.05), reduced GFR (12%, P < 0.05), increased PV (26%, P < 0.05) and unchanged MAP and NN. The TG increased in both groups of treated offspring (21%, P < 0.05), whereas Chol increased only in the postnatally sodium-overloaded group. We conclude that salt overload from the prenatal stage until weaning leads to alterations in lipid metabolism and in the renal function of the pups, which are additional to those alterations seen in rats only overloaded prenatally.
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Affiliation(s)
- Henriqueta D Cardoso
- Departamento de Fisiologia e Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife, PE, Brazil
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Abstract
Uterine blood supply is a critical issue for fetal well-being, since it carries all the nutrients, including O2, required for fetal growth and gets rid of several fetal waste products. During pregnancy, uterine blood flow increases by almost 20 times and this is permitted by marked remodeling of the vessel wall. In the rat, uterine arterial remodeling takes place in the last 7-8 days of gestation (over 22) and is reversible in the postpartum period upon a similar time frame. It was also described as both hypertrophy and hyperplasia of all the constituents of the vascular wall. Several hypotheses have been proposed to explain such a phenomenon, including the driving role not only of sexual steroid hormones, progesterone and estrogens, but also of trophic factors of fetal origin. We have shown that alterations of the renin-angiotensin-aldosterone system, by manipulating sodium intake in the rats, reduced the pregnancy-induced remodeling of uterine arteries. These maneuvres resulted in the birth of pups that had characteristics of intrauterine growth restriction or in the development in the mother of "experimental" gestational hypertension, depending on, respectively, restriction or increased of sodium intake.
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Ianosi-Irimie M, Vu HV, Whitbred JM, Pridjian CA, Nadig JD, Williams MY, Wrenn DC, Pridjian G, Puschett JB. A Rat Model of Preeclampsia. Clin Exp Hypertens 2009; 27:605-17. [PMID: 16303637 DOI: 10.1080/10641960500298608] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Preeclampsia/eclampsia is a disorder of human pregnancy that continues to exact significant maternal morbidity and mortality and fetal wastage. Therapy of these disorders has not changed in over 50 years and there are no proven preventive measures. We describe a model of the development of a syndrome in the pregnant rat that resembles preeclampsia, which results from the imposition of excessive volume expansion early in gestation. We administered desoxycorticosterone acetate (DOCA) to pregnant animals whose drinking water had been replaced with saline. We compared the results obtained in these animals with those resulting from the study of control, virgin animals, virgin animals receiving DOCA and saline, and normal pregnant (NP) animals. The virgin animals given DOCA and saline did not become hypertensive. The experimental paradigm in the DOCA plus saline pregnant (PDS) animals provides many of the phenotypic characteristics of the human disorder including the development of hypertension, proteinuria, and intrauterine growth restriction. In addition, the mean blood nitrite/nitrate concentration was reduced in the PDS rats compared with their NP counterparts. We propose that this model may prove to be useful in the study of the human condition.
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Affiliation(s)
- Monica Ianosi-Irimie
- Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana, USA
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24
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Iacono A, Bianco G, Mattace Raso G, Esposito E, d'Emmanuele di Villa Bianca R, Sorrentino R, Cuzzocrea S, Calignano A, Autore G, Meli R. Maternal adaptation in pregnant hypertensive rats: improvement of vascular and inflammatory variables and oxidative damage in the kidney. Am J Hypertens 2009; 22:777-83. [PMID: 19373215 DOI: 10.1038/ajh.2009.68] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Mechanisms of normalization of blood pressure in spontaneously hypertensive rats (SHR) during pregnancy were investigated. We hypothesized that at the end of pregnancy (20th day), the modified renal renin-angiotensin system (RAS) plays a pivotal role in this effect associated with reduced inflammation and oxidative damage. METHODS We measured blood pressure and heart rate (HR) using a noninvasive tail-cuff method in conscious SHR and Wistar Kyoto rats (WKY). Nonpregnant (-NP) or pregnant (-P) SHR and WKY were used to compare the changes of angiotensin II (ANG II) type 1 (AT1) and type 2 (AT2) receptor expression in the kidney. Renal modification of proinflammatory enzyme expression, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) and their transcription factor nuclear factor-kappaB (NF-kappaB) were also evaluated. Renal malonyldialdehyde (MDA) content and protein nitrotyrosylation, as indicators of oxidative stress, were assessed. Moreover monocyte chemotactic protein-1 (MCP-1) mRNA was determined. RESULTS Our findings indicate that the significant reduction of blood pressure induced by pregnancy in the SHR strain could be related to reduced AT1 and increased AT2 expression. We also saw a significant decline in renal NF-kappaB, COX-2, iNOS, and macrophage infiltration, as well as the fall in oxidative stress indicators. CONCLUSIONS The increased proinflammatory and oxidative variables, seen in SHR, are strongly ameliorated by pregnancy. In pregnant SHR animals, the adaptive and compensative changes of RAS and inflammation in the kidney seem to contribute to the reduction of blood pressure near term.
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Moinier BM, Drueke TB. Aphrodite, sex and salt--from butterfly to man. Nephrol Dial Transplant 2008; 23:2154-61. [DOI: 10.1093/ndt/gfm956] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Leandro SM, Furukawa LNS, Shimizu MHM, Casarini DE, Seguro AC, Patriarca G, Coelho MS, Dolnikoff MS, Heimann JC. Low birth weight in response to salt restriction during pregnancy is not due to alterations in uterine-placental blood flow or the placental and peripheral renin-angiotensin system. Physiol Behav 2008; 95:145-51. [PMID: 18572207 DOI: 10.1016/j.physbeh.2008.05.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 05/12/2008] [Accepted: 05/13/2008] [Indexed: 11/25/2022]
Abstract
A number of studies conducted in humans and in animals have observed that events occurring early in life are associated with the development of diseases in adulthood. Salt overload and restriction during pregnancy and lactation are responsible for functional (hemodynamic and hormonal) and structural alterations in adult offspring. Our group observed that lower birth weight and insulin resistance in adulthood is associated with salt restriction during pregnancy. On the other hand, perinatal salt overload is associated with higher blood pressure and higher renal angiotensin II content in adult offspring. Therefore, we hypothesised that renin-angiotensin system (RAS) function is altered by changes in sodium intake during pregnancy. Such changes may influence fetoplacental blood flow and thereby fetal nutrient supply, with effects on growth in utero and, consequently, on birth weight. Female Wistar rats were fed low-salt (LS), normal-salt (NS), or high-salt (HS) diet, starting before conception and continuing until day 19 of pregnancy. Blood pressure, heart rate, fetuses and dams' body weight, placentae weight and litter size were measured on day 19 of pregnancy. Cardiac output, uterine and placental blood flow were also determined on day 19. Expressions of renin-angiotensin system components and of the TNF-alpha gene were evaluated in the placentae. Plasma renin activity (PRA) and plasma and tissue angiotensin-converting enzyme (ACE) activity, as well as plasma and placental levels of angiotensins I, II, and 1-7 were measured. Body weight and kidney mass were greater in HS than in NS and LS dams. Food intake did not differ among the maternal groups. Placental weight was lower in LS dams than in NS and HS dams. Fetal weight was lower in the LS group than in the NS and HS groups. The PRA was greater in LS dams than in NS and HS dams, although ACE activity (serum, cardiac, renal, and placental) was unaffected by the level of sodium intake. Placental levels of angiotensins I and II were lower in the HS group than in the NS and LS groups. Placental angiotensin receptor type 1 (AT(1)) gene expression and levels of thiobarbituric acid reactive substances (TBARS) were higher in HS dams, as were uterine blood flow and cardiac output. The degree of salt intake did not influence plasma sodium, potassium or creatinine. Although fractional sodium excretion was higher in HS dams than in NS and LS dams, fractional potassium excretion was unchanged. In conclusion, findings from this study indicate that the reduction in fetal weight in response to salt restriction during pregnancy does not involve alterations in uterine-placental perfusion or the RAS. Moreover, no change in fetal weight is observed in response to salt overload during pregnancy. However, salt overload did lead to an increase in placental weight and uterine blood flow associated with alterations in maternal plasma and placental RAS. Therefore, these findings indicate that changes in salt intake during pregnancy lead to alterations in uterine-placental perfusion and fetal growth.
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Affiliation(s)
- Sandra Márcia Leandro
- Department of Internal Medicine, Laboratory of Experimental Hypertension, University of São Paulo School of Medicine, São Paulo, Brazil
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Abstract
Despite widespread accessibility to prenatal care, little is known on the mechanisms initiating early maternal adaptation to pregnancy. Moreover, preeclampsia and intrauterine growth retardation remain the most frequent and serious complications of pregnancy. Recent studies, both in humans and in laboratory animals, have shown that very early events in gestation may be important determinants for the continuation of healthy pregnancy. Certain of these early adaptations appear to be linked to the corpus luteum of pregnancy, as ovarian steroid hormones (especially progesterone) would set the basic hemodynamic conditions, more specifically, generalized vasodilation. This new hemodynamic setup initiates a vicious cycle in which the renin - angiotensin - aldosterone system is activated, together with the resetting of the control of antidiuretic hormone secretion relative to plasma osmolality. This leads to a gradual and substantial increase in plasma volume and a parallel increase in cardiac function (both heart rate and stroke volume) with the goal of maintaining blood pressure in the face of the generalised vasodilation. This includes the creation of a functional arterio-venous shunt represented by the utero-placental circulation. By the end of the first trimester, the decrease in peripheral vascular resistance is marked relative to the increase in cardiac output, resulting in a significant decrease in blood pressure that will be maintained until the third trimester. It is proposed that in preeclampsia, these very early events (vasodilation - increased plasma volume) fail to occur, resulting in an absence of the usual decrease in blood pressure, which is normally seen in the second trimester of pregnancy, and hypertension in the third trimester. Experimental animals, especially the rat, are suitable models to study this early maternal adaptation to pregnancy, since both endocrine and hemodynamic changes appear to be similar to humans.
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Affiliation(s)
- Jean St-Louis
- Centre de Recherche, CHU Sainte-Justine, Département d'Obstétrique et Gynécologie, Faculté de Médecine, Université de Montréal, 3175, chemin de la Côte Sainte-Catherine, Montréal (Québec), H3T 1C5 Canada.
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Beauséjour A, Houde V, Bibeau K, Gaudet R, St-Louis J, Brochu M. Renal and cardiac oxidative/nitrosative stress in salt-loaded pregnant rat. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1657-65. [PMID: 17652367 DOI: 10.1152/ajpregu.00090.2007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Sodium supplementation given for 1 wk to nonpregnant rats induces changes that are adequate to maintain renal and circulatory homeostasis as well as arterial blood pressure. However, in pregnant rats, proteinuria, fetal growth restriction, and placental oxidative stress are observed. Moreover, the decrease in blood pressure and expansion of circulatory volume, normally associated with pregnancy, are prevented by high-sodium intake. We hypothesized that, in these pregnant rats, a loss of the balance between prooxidation and antioxidation, particularly in kidneys and heart, disturbs the normal course of pregnancy and leads to manifestations such as gestational hypertension. We thus investigated the presence of oxidative/nitrosative stress in heart and kidneys following high-sodium intake in pregnant rats. Markers of this stress [8-isoprostaglandin F(2alpha) (8-iso-PGF(2alpha)) and nitrotyrosine], producer of nitric oxide [nitric oxide synthases (NOSs)], and antioxidants [superoxide dismutase (SOD) and catalase] were measured. Then, molecules (Na(+)-K(+)-ATPase and aconitase) or process [apoptosis (Bax and Bcl-2), inflammation (monocyte chemoattractant protein-1, connective tissue growth factor, and TNF-alpha)] susceptible to free radicals was determined. In kidneys from pregnant rats on 1.8% NaCl-water, NOSs, apoptotic index, and nitrotyrosine expression were increased, whereas Na(+)-K(+)-ATPase mRNA and activity were decreased. In the left cardiac ventricle of these rats, heightened nitrotyrosine, 8-iso-PGF(2alpha), and catalase activity together with reduced endothelial NOS protein expression and SOD and aconitase activities were observed. These findings suggest that oxidative/nitrosative stress in kidney and left cardiac ventricle destabilizes the normal course of pregnancy and could lead to gestational hypertension.
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Affiliation(s)
- Annie Beauséjour
- Research Centre, CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, QC, Canada, H3T 1C5
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Porter JP, King SH, Honeycutt AD. Prenatal high-salt diet in the Sprague-Dawley rat programs blood pressure and heart rate hyperresponsiveness to stress in adult female offspring. Am J Physiol Regul Integr Comp Physiol 2007; 293:R334-42. [PMID: 17491116 DOI: 10.1152/ajpregu.00887.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several animal models have been developed to study fetal programming of hypertension. One model involves feeding high-salt (HS) diet to rats before and during pregnancy, during lactation, and after weaning for 10 days. In the present investigation, we limited HS diet to the prenatal period in an attempt to find a narrower critical window for fetal programming. The HS diet did not result in low-birth weight offspring. In the adult offspring, radiotelemetry was used to assess blood pressure and heart rate in the conscious unstressed state. As adults, the HS offspring were not hypertensive compared with normal-salt (NS) control animals. However, the pressor and tachycardic responses to 1-h of restraint were significantly enhanced in HS female offspring, and recovery after restraint was delayed. This was accompanied by an increase in relative expression of corticotropin-releasing hormone (CRH) mRNA in the paraventricular nucleus of the hypothalamus during basal and stressed conditions. There was no augmented stress response or relative increase in CRH mRNA in adult HS male offspring. When challenged with 1 wk of 8% NaCl diet as adults, neither HS male nor female offspring exhibited salt sensitivity compared with NS groups. These data show that a high-salt diet limited to the prenatal period is not sufficient to program hypertension in adult offspring. However, this narrower critical period is sufficient to imprint a lasting hyperresponsiveness to stress, at least in adult female offspring. These data indicate that excessive maternal salt intake during pregnancy can adversely affect the cardiovascular health of adult offspring.
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Affiliation(s)
- James P Porter
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
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Beauséjour A, Bibeau K, Lavoie JC, St-Louis J, Brochu M. Placental oxidative stress in a rat model of preeclampsia. Placenta 2006; 28:52-8. [PMID: 16469376 DOI: 10.1016/j.placenta.2005.12.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 12/07/2005] [Accepted: 12/07/2005] [Indexed: 10/25/2022]
Abstract
The onset of preeclampsia is associated with increased maternal insult that could affect placental function. By increasing sodium intake (0.9% or 1.8% NaCl in drinking water) during the last week of gestation in the rat, we developed an animal model that shows many characteristics of preeclampsia such as increased blood pressure, decreased circulatory volume and diminished activity of the renin-angiotensin-aldosterone system. The aim of the present study was to determine in this model whether maternal perturbations in pregnancy lead to placental oxidative stress. Sprague-Dawley pregnant rats receiving salted-water were compared to not-supplemented pregnant rats. Markers of oxidative stress, ensuing cell death, and changes in the production of vasoactive substances (prostanoids: thromboxane, TxB(2); and prostacyclin, PGF(1alpha)) and the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha) were measured in the placenta. In tissue from pregnant rats on 1.8% NaCl supplement, 8-iso-PGF(2alpha) levels, TxB(2)/6-keto-PGF(1alpha) ratios, total TNF-alpha RNA expression, as well as the apoptotic index (Bax/Bcl-2 ratio) and endothelial nitric oxide synthase protein expression increase while total glutathione content decreases. These findings demonstrate that maternal insult during gestation induced an imbalance in the oxidative environment in the placenta favouring oxidation. This was accompanied by an increased synthesis of vasoconstrictive substances and TNF-alpha by the placenta as well as the increased rate of placental cell apoptosis.
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Affiliation(s)
- A Beauséjour
- Research Centre, Hôpital Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC, Canada H3T 1C5
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St-Louis J, Sicotte B, Beauséjour A, Brochu M. Remodeling and angiotensin II responses of the uterine arcuate arteries of pregnant rats are altered by low- and high-sodium intake. Reproduction 2006; 131:331-9. [PMID: 16452726 DOI: 10.1530/rep.1.00565] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lowering and increasing sodium intake in pregnant rats evoke opposite changes in renin–angiotensin–aldosterone system (RAAS) activity and are associated with alterations of blood volume expansion. As augmented uterine blood flow during gestation is linked to increased circulatory volume, we wanted to determine if low- and high-sodium intakes affect the mechanical properties and angiotensin II (AngII) responses of the uterine vasculature. Non-pregnant and pregnant rats received a normal sodium (0.22% Na+) diet. On the 15th day of gestation some animals were moved to a low-sodium (0.03%) diet, whereas others were given NaCl supplementation as beverage (saline, 0.9% or 1.8%) for 7 days. All rats were killed after 7 days of treatment (eve of parturition). Uterine arcuate arteries (>100 μm) were set up in wire myographs under a tension equivalent to 50 mmHg transmural pressure. The pregnancy-associated increase in diameter of the uterine arteries was significantly attenuated on the low-sodium diet and 1.8% NaCl supplementation. The arcuate arteries of non-pregnant rats on the low-sodium diet showed markedly increased responses to AngII and phenylephrine (Phe). Pregnancy also resulted in heightened responses to AngII and Phe that were significantly reduced for the former agent in rats on the low-sodium diet. Sodium supplementation of non-pregnant rats did not affect the reactivity of the uterine arteries to AngII, but significantly reduced the effect of Phe (1 μmol/l). High salt also significantly diminished the elevated responses to AngII in the arteries of pregnant animals. It was observed that altered sodium intake affects the mechanical and reactive properties of the uterine arcuate arteries more importantly in pregnant than in non-pregnant rats. Low-salt intake similarly affected the reactivity of the uterine arcuate arteries to AngII and Phe, whereas high-salt intake more specifically affected AngII responses. These results showed that perturbations of sodium intake have major impacts on the structure and functions of the uterine arterial circulation, indicating RAAS involvement in uterine vascular remodeling and function during gestation.
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Affiliation(s)
- Jean St-Louis
- Laboratoire de Recherche Fondamentale en Obstétrique, Centre de Recherche, Département d'Obstétrique et Gynécologie, Hôpital Sainte-Justine, Université de Montréal, 175 Ch. Côte Sainte-Catherine, Montréal, Québec H3T 1C5, Canada.
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Myasnikova VV, Galenko-Yaroshevskii PA, Lysenkov SP, Kupreishvili VZ, Rizhvadze MR, Sukoyan GV. Pharmacological correction of changes in the lung-placenta system under experimental conditions. Bull Exp Biol Med 2005; 140:201-4. [PMID: 16283001 DOI: 10.1007/s10517-005-0445-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Pathological changes in the fetoplacental complex and lung-placenta system were observed in rats with experimental gestosis produced by long-term feeding of a high-sodium diet. We revealed a decrease in the weights of the placenta and fetus, pulmonary fibrinolytic dysfunction, and increased production of cortisol. The course of fraxiparine treatment in animals with experimental gestosis decreased coagulation activity of the arterial blood, increased the weights of the placenta and fetus, and reduced the concentration of stress hormone cortisol.
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Affiliation(s)
- V V Myasnikova
- Krasnodar Branch, Southern Department of the Russian Academy of Medical Sciences.
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Myasnikova VV, Lysenkov SP, Galenko-Yaroshevskii PA, Barbakidze TR, Sukoyan GV. Disorders in the lungs-placenta system under conditions of experimental gestosis in rats. Bull Exp Biol Med 2005; 140:18-21. [PMID: 16254610 DOI: 10.1007/s10517-005-0400-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Study of the arteriovenous difference in hormone levels and hemostasis parameters in rats with experimental gestosis induced by hyper-sodium diet showed decreased production of progesterone, increased level of hydrocortisone (resultant from its increased production and additional release of the hormone by the lungs), hypercoagulation, and retarded fetal development. Involvement of the lungs into the maintenance of optimum rheological parameters of arterial blood and a relationship between the level of fetoplacental hormones and the function of pulmonary fibrinolytic filter were detected.
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Affiliation(s)
- V V Myasnikova
- Krasnodar Affiliated Branch of Southern Bureau of Russian Academy of Medical Sciences; N. V. Karsanov National Research Center of Medical Biophysics and Introduction of New Biomedical Technologies, Tbilisi
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Myasnikova VV, Galenko-Yaroshevskii PA, Lysenkov SP, Gigineishvili MA, Berberashvili TM. Pharmacological correction of hemostasis-regulating function of the lungs in rats with uncomplicated pregnancy and experimental gestosis. Bull Exp Biol Med 2005; 139:651-4. [PMID: 16224571 DOI: 10.1007/s10517-005-0368-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Fetal growth retardation, hypercoagulation, and changes in pulmonary fibrinolytic activity were observed during experimental gestosis induced by long-term feeding of a high-sodium diet. The course of fraxiparine treatment to correct gestosis improved hemostasis-regulating lung function, decreased coagulation activity of the arterial blood, and increased the weights of the placenta and fetus.
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Affiliation(s)
- V V Myasnikova
- Krasnodar Branch, Southern Department of the Russian Academy of Medical Sciences, Russia
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Bédard S, Sicotte B, St-Louis J, Brochu M. Modulation of body fluids and angiotensin II receptors in a rat model of intra-uterine growth restriction. J Physiol 2004; 562:937-50. [PMID: 15539403 PMCID: PMC1665548 DOI: 10.1113/jphysiol.2004.064683] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We previously reported that sodium restriction during pregnancy reduces plasma volume expansion and promotes intra-uterine growth restriction (IUGR) in rats while it activates the renin-angiotensin-aldosterone system (RAAS). In the present study, we proceeded to determine whether expression of the two angiotensin II (ANGII) receptor subtypes (AT(1) and AT(2)) change in relation to maternal water-electrolyte homeostasis and fetal growth. To this end, pregnant (gestation day 15) and non-pregnant Sprague-Dawley rats were randomly assigned to two groups fed either normal, or Na(+)-restricted diets for 7 days. At the end of the treatment period, plasma aldosterone and renin activity as well as plasma and urine electrolytes were measured. Determinations for AT(1) and AT(2) mRNA and protein were made by RNase protection assay and photoaffinity labelling, respectively, using a number of tissues implicated in volume regulation and fetal growth. In non-pregnant rats, Na(+) restriction decreases Na(+) excretion without altering plasma volume, plasma Na(+) concentration or the expression of AT(1) and AT(2) mRNA or protein in the tissues examined. In normally fed pregnant rats when compared to non-pregnant controls, AT(1) mRNA increases in the hypothalamus as well as pituitary and declines in uterine arteries, while AT(1) protein decreases in the kidney and AT(2) mRNA declines in the adrenal cortex. In pregnant rats, Na(+) restriction induces a decrease in plasma Na(+), an increase in plasma urea, as well as a decline in renal urea and creatinine clearance rates. Protein levels for both AT(1) and AT(2) in the pituitary and AT(2) mRNA in the adrenal cortex are lower in the Na(+)-restricted pregnant group when compared to normally fed pregnant animals. Na(+) restriction also induces a decrease in AT(1) protein in the placenta. In conclusion, these results suggest that pregnancy may increase sensitivity to Na(+) depletion by the tissue-specific modulation of ANGII receptors. Finally, these receptors may be implicated in the IUGR response to low Na(+).
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Affiliation(s)
- Sophie Bédard
- Centre de Recherche, Department of Obstetrics-Gynecology, Université de Montréal, Hôpital Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Québec, Canada H3T 1C5
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Auger K, Beauséjour A, Brochu M, St-Louis J. Increased Na+ intake during gestation in rats is associated with enhanced vascular reactivity and alterations of K+ and Ca2+ function. Am J Physiol Heart Circ Physiol 2004; 287:H1848-56. [PMID: 15205166 DOI: 10.1152/ajpheart.00055.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gestation is associated with decreased blood pressure and resistance to the effects of vasoconstrictor agents. A recent study showed that pregnant rats, on increased sodium intake, present physiological changes that resemble those observed in preeclampsia. We investigated the effects of sodium supplementation on reactivity and on potassium and Ca2+ channel activity in blood vessels during gestation. Sodium supplements, 0.9% or 1.8% NaCl as drinking water, were given to nonpregnant and pregnant rats for 7 days (last week of gestation). Reactivity to phenylephrine (PE), KCl, arginine vasopressin (AVP), and tetraethylammonium (TEA) was measured in aortic rings under modulation of potassium and calcium channels. TEA, a nonselective K+ channel inhibitor, induced concentration-dependent responses in aortic rings from nonpregnant but not in those from pregnant rats. The response to TEA was restored in rings from pregnant rats after preincubation with 10 mmol/l KCl. Sodium supplementation did not affect the response to TEA in the aortas of pregnant animals. After sodium supplementation, maximum responses to PE and AVP were decreased and increased in aortic rings from nonpregnant and pregnant rats, respectively. Cromakalim (an ATP-sensitive K+ channel activator)-induced inhibition of the responses to the three vasoconstrictors was more striking in aorta from nonpregnant than pregnant rats on regular diet, whereas it produced similar inhibition in tissues from both groups of animals on 0.9% and 1.8% NaCl. NS-1619 (a Ca2+-sensitive K+ activator) elicited heightened effects in the aortas of pregnant animals receiving 0.9% NaCl supplementation. Nifedipine (a Ca2+ channel blocker) caused greater inhibition of the contractile responses in tissues from nonpregnant rats on regular diet, and its action was increased in pregnant rats on sodium-supplemented diets. These data demonstrate that augmented sodium intake during gestation in the rat is linked with the reversal of gestational-associated resistance to vasopressors and indicate that this is an experimental model showing some features of gestational hypertension.
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Affiliation(s)
- Karine Auger
- Centre de Recherche, Hôpital Sainte-Justine, 3175 Côte Sainte-Catherine, Montréal, Québec, Canada H3T 1C5
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