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Roberts DN, Vallén P, Cronhjort M, Alfvén T, Sandblom G, Törnroth-Horsefield S, Jensen BL, Lönnqvist PA, Frithiof R, Carlström M, Krmar RT. Perioperative water and electrolyte balance and water homeostasis regulation in children with acute surgery. Pediatr Res 2023; 94:1373-1379. [PMID: 36759747 PMCID: PMC9909148 DOI: 10.1038/s41390-023-02509-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/25/2022] [Accepted: 01/24/2023] [Indexed: 02/11/2023]
Abstract
BACKGROUND Hospital-acquired hyponatremia remains a feared event in patients receiving hypotonic fluid therapy. Our objectives were to assess post-operative plasma-sodium concentration and to provide a physiological explanation for plasma-sodium levels over time in children with acute appendicitis. METHODS Thirteen normonatremic (plasma-sodium ≥135 mmol/L) children (8 males), median age 12.3 (IQR 11.5-13.5) years participated in this prospective observational study (ACTRN12621000587808). Urine was collected and analyzed. Blood tests, including renin, aldosterone, arginine-vasopressin, and circulating nitric oxide substrates were determined on admission, at induction of anesthesia, and at the end of surgery. RESULTS On admission, participants were assumed to be mildly dehydrated and were prescribed 50 mL/kg of Ringer's acetate intravenously followed by half-isotonic saline as maintenance fluid therapy. Blood tests, urinary indices, plasma levels of aldosterone, arginine-vasopressin, and net water-electrolyte balance indicated that participants were dehydrated on admission. Although nearly 50% of participants still had arginine-vasopressin levels that would have been expected to produce maximum antidiuresis at the end of surgery, electrolyte-free water clearance indicated that almost all participants were able to excrete net free water. No participant became hyponatremic. CONCLUSIONS The use of moderately hypotonic fluid therapy after correction of extracellular fluid deficit is not necessarily associated with post-operative hyponatremia. IMPACT Our observations show that in acutely ill normonatremic children not only the composition but also the amount of volume infused influence on the risk of hyponatremia. Our observations also suggest that perioperative administration of hypotonic fluid therapy is followed by a tendency towards hyponatremia if extracellular fluid depletion is left untreated. After correcting extracellular deficit almost all patients were able to excrete net free water. This occurred despite nearly 50% of the cohort having high circulating plasma levels of arginine-vasopressin at the end of surgery, suggesting a phenomenon of renal escape from arginine-vasopressin-induced antidiuresis.
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Affiliation(s)
| | - Paula Vallén
- Department of Anesthesia and Intensive Care, Södersjukhuset, Stockholm, Sweden
| | - Maria Cronhjort
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Tobias Alfvén
- Sachsska Children and Youth Hospital, Stockholm, Sweden
- Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden
| | - Gabriel Sandblom
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
- Department of Surgery, Södersjukhuset, Stockholm, Sweden
| | | | - Boye L Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
- Department of Urology, Odense University Hospital, Odense, Denmark
| | - Per-Arne Lönnqvist
- Department of Pediatric Perioperative Medicine and Intensive Care, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum 5B, Stockholm, Sweden
| | - Robert Frithiof
- Department of Surgical Sciences, Anesthesiology, and Intensive Care, Uppsala University, Uppsala, Sweden
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum 5B, Stockholm, Sweden
| | - Rafael T Krmar
- Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum 5B, Stockholm, Sweden.
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McArdle Z, Singh R, Moritz K, Schreuder M, Denton K. Brief early life angiotensin-converting enzyme inhibition attenuates the diuretic response to saline loading in sheep with solitary functioning kidney. Clin Sci (Lond) 2023; 137:1285-1296. [PMID: 37565514 PMCID: PMC10447225 DOI: 10.1042/cs20230663] [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] [Received: 06/15/2023] [Revised: 07/28/2023] [Accepted: 08/11/2023] [Indexed: 08/12/2023]
Abstract
A solitary functioning kidney (SFK) from birth predisposes to hypertension and kidney dysfunction, and this may be associated with impaired fluid and sodium homeostasis. Brief and early angiotensin-converting enzyme inhibition (ACEi) in a sheep model of SFK delays onset of kidney dysfunction. We hypothesized that modulation of the renin-angiotensin system via brief postnatal ACEi in SFK would reprogram renal sodium and water handling. Here, blood pressure (BP), kidney haemodynamics and kidney excretory function were examined in response to an isotonic saline load (0.13 ml/kg/min, 180 min) at 20 months of age in SFK (fetal unilateral nephrectomy at 100 days gestation; term 150 days), sham and SFK+ACEi sheep (ACEi in SFK 4-8 weeks of age). Basal BP was higher in SFK than sham (∼13 mmHg), and similar between SFK and SFK+ACEi groups. Saline loading caused a small increase in BP (∼3-4 mmHg) the first 2 h in SFK and sham sheep but not SFK+ACEi sheep. Glomerular filtration rate did not change in response to saline loading. Total sodium excretion was similar between groups. Total urine excretion was similar between SFK and sham animals but was ∼40% less in SFK+ACEi animals compared with SFK animals. In conclusion, the present study indicates that water homeostasis in response to a physiological challenge is attenuated at 20 months of age by brief early life ACEi in SFK. Further studies are required to determine if ACEi in early life in children with SFK could compromise fluid homeostasis later in life.
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Affiliation(s)
- Zoe McArdle
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Reetu R. Singh
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Karen M. Moritz
- Child Health Research Centre and School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Michiel F. Schreuder
- Department of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kate M. Denton
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
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3
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Vukajlovic T, Sailer CO, Asmar A, Jensen BL, Vogt DR, Christ-Crain M, Winzeler B. Effect of a 3-Week Treatment with GLP-1 Receptor Agonists on Vasoactive Hormones in Euvolemic Participants. J Clin Endocrinol Metab 2022; 107:e2581-e2589. [PMID: 35134170 DOI: 10.1210/clinem/dgac063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Glucagon-like-peptide-1 receptor agonists (GLP-1 RAs) exert cardiovascular benefits by reducing plasma glucose, body weight, and blood pressure. The blood pressure-lowering effect may be mediated by angiotensin II (ANG II) suppression and consecutive natriuresis. However, the role of ANG II and other vasoactive hormones on GLP-1 RA treatment has not been clearly defined. OBJECTIVE This work aimed to investigate the effect of a 3-week treatment with the GLP-1 RA dulaglutide on vasoactive hormones, that is, renin, ANG II, aldosterone, mid-regional proatrial natriuretic peptide (MP-proANP), and natriuresis in euvolemic participants. METHODS Randomized, double-blinded, placebo-controlled, crossover trials were conducted at University Hospital Basel, Switzerland. A total of 54 euvolemic participants, including 20 healthy individuals and 34 patients with primary polydipsia, received a subcutaneous injection of dulaglutide (Trulicity) 1.5 mg and placebo (0.9% sodium chloride) once weekly over a 3-week treatment phase. RESULTS After a 3-week treatment phase, dulaglutide showed no effect on plasma renin, plasma ANG II, or plasma aldosterone levels in comparison to placebo. Natriuresis remained unchanged or decreased on dulaglutide depending on the measured parameter. Dulaglutide significantly decreased plasma MR-proANP levels (treatment effect: 10.60 pmol/L; 95% CI, -14.70 to -7.90; P < .001) and systolic blood pressure (median: 3 mm Hg; 95% CI, -5 to 0; P = .036), whereas heart rate increased (median: 5 bpm; 95% CI, 3-11; P < .001). CONCLUSION In euvolemic participants, a 3-week treatment of dulaglutide reduced systolic blood pressure independently of plasma renin, ANG II, or aldosterone levels and urinary sodium excretion. The reduction in MR-proANP might be secondary to reduced arterial pulse pressure.
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Affiliation(s)
- Tanja Vukajlovic
- Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, 4031 Basel, Switzerland
- Department of Clinical Research, University of Basel, 4056 Basel, Switzerland
| | - Clara O Sailer
- Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, 4031 Basel, Switzerland
- Department of Clinical Research, University of Basel, 4056 Basel, Switzerland
| | - Ali Asmar
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Copenhagen University Hospital, 2100 Copenhagen, Denmark
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, 2100 Copenhagen, Denmark
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, 5230 Odense, Denmark
| | - Deborah R Vogt
- Clinical Trial Unit, Department of Clinical Research, University of Basel and University Hospital Basel, 4056 Basel, Switzerland
| | - Mirjam Christ-Crain
- Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, 4031 Basel, Switzerland
- Department of Clinical Research, University of Basel, 4056 Basel, Switzerland
| | - Bettina Winzeler
- Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, 4031 Basel, Switzerland
- Department of Clinical Research, University of Basel, 4056 Basel, Switzerland
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Dossche L, Michelet R, De Bruyne P, Van Herzeele C, Gasthuys E, Rittig S, Vermeulen A, Vande Walle J. Desmopressin oral lyophilisate in young children: new insights in pharmacokinetics and pharmacodynamics. Arch Dis Child 2021; 106:597-602. [PMID: 32737054 DOI: 10.1136/archdischild-2019-318225] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 04/05/2020] [Accepted: 06/18/2020] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To study the pharmacokinetic (PK)/pharmacodynamic (PD) characteristics of desmopressin (dDAVP) oral lyophilisate in children below the age of 8 years with special emphasis on age-related and size-related differences in bioavailability. DESIGN Open label, non-randomised, interventional PK and PD trial. SETTING Single-centre study. PATIENTS Children (age: 6 months to 8 years) with nocturnal polyuria, including both children with uropathy or nephropathy (glomerular filtration rate >60 mL/min/1.73 m²) and children (age: 5-8 years) with severe monosymptomatic nocturnal enuresis, who were unresponsive to treatment with 400 µg of the dDAVP tablet for at least 1 month. INTERVENTIONS After a water load, dDAVP was administered sublingually as a single dose of oral lyophilisate. Subsequently, blood and urine samples were collected until 7 hours post-administration. MAIN OUTCOME MEASURES Non-compartmental analysis of PK parameters was performed based on dDAVP concentrations in both plasma and urine. To evaluate the effect of dDAVP lyophilisate (PD parameters), the urinary concentration capacity (urine osmolality (mOsm/kg)) and antidiuretic effect (diuresis rate (mL/kg/h)) were calculated. RESULTS The PK data support the need for size-dependent dosing in children. Body weight was shown to be a significant covariate for apparent clearance (CL/F) and apparent volume of distribution (Vd/F). A double absorption peak of dDAVP lyophilisate in the first 2 hours post-administration was demonstrated. CONCLUSIONS For the first time, a double absorption profile of dDAVP lyophilisate was found in children, questioning extrapolation of bioequivalence from adults towards children. Moreover, the need for size-adapted dosing regimens of dDAVP lyophilisate in young children is indicated. TRIAL REGISTRATION NUMBER NTC02584231.
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Affiliation(s)
- Lien Dossche
- Department of Internal Medicine and Paediatrics, Faculty of Medicine and Health Sciences, Ghent University, Gent, Belgium .,Department of Paediatric Nephrology, University Hospital Ghent, Gent, Belgium
| | - Robin Michelet
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Gent, Belgium.,Department of Clinical Pharmacy & Biochemistry, Institute of Pharmacy, Freie Universitat Berlin, Berlin, Berlin, Germany
| | - Pauline De Bruyne
- Department of Internal Medicine and Paediatrics, Ghent University, Gent, Belgium
| | - Charlotte Van Herzeele
- Department of Internal Medicine and Paediatrics, Faculty of Medicine and Health Sciences, Ghent University, Gent, Belgium.,Department of Clinical Psychology, AZ Sint-Jan Brugge-Oostende AV, Brugge, Belgium
| | - Elke Gasthuys
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Gent, Belgium
| | - Søren Rittig
- Departments of Clinical Medicine and Paediatrics, Aarhus University Hospital, Aarhus, Denmark
| | - An Vermeulen
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Gent, Belgium
| | - Johan Vande Walle
- Department of Internal Medicine and Paediatrics, Faculty of Medicine and Health Sciences, Ghent University, Gent, Belgium.,Department of Paediatric Nephrology, University Hospital Ghent, Gent, Belgium
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Asmar A, Cramon PK, Asmar M, Simonsen L, Sorensen CM, Madsbad S, Hartmann B, Holst JJ, Hovind P, Jensen BL, Bülow J. The Renal Extraction and the Natriuretic Action of GLP-1 in Humans Depend on Interaction With the GLP-1 Receptor. J Clin Endocrinol Metab 2021; 106:e11-e19. [PMID: 32927478 DOI: 10.1210/clinem/dgaa643] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 09/11/2020] [Indexed: 02/04/2023]
Abstract
PURPOSE The natriuretic effect of glucagon-like peptide-1 (GLP-1) in humans is independent of changes in renal plasma flow (RPF) and glomerular filtration rate (GFR) but may involve suppression of angiotensin II (ANG II) and a significant (~45%) renal extraction of GLP-1. The current study was designed to investigate the consequences for the renal extraction and the natriuretic effect of blocking GLP-1 receptors with the specific GLP-1 receptor antagonist, Exendin 9-39 (Ex 9-39). METHODS Under fixed sodium intake for 4 days before each study day, 6 healthy male participants were recruited from our recent study where GLP-1 or vehicle was infused (1). In the present new experiments, participants were examined during a 3-hour infusion of GLP-1 (1.5 pmol/kg/min) together with a 3.5-hour infusion of Ex 9-39 (900 pmol/kg/min). Timed urine collections were conducted throughout the experiments. Renal extraction of GLP-1 as well as RPF and GFR were measured via Fick's principle after catheterization of a renal vein. Arterial plasma renin, ANG II, and aldosterone concentrations were measured. RESULTS Co-infusion of Ex 9-39 significantly reduced renal extraction of GLP-1 to ~25% compared with GLP-1 infusion alone (~45%). Urinary sodium excretions remained at baseline levels during co-infusion of Ex 9-39 as well as vehicle. By contrast, GLP-1 infusion alone resulted in a 2-fold increase in natriuresis. Ex 9-39 abolished the GLP-1-induced decrease in arterial ANG II concentrations. RPF and GFR remained unchanged during all experiments. CONCLUSIONS Renal extraction of GLP-1 and its effect on natriuresis are both dependent on GLP-1 receptor activation in healthy humans.
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Affiliation(s)
- Ali Asmar
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Per K Cramon
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Meena Asmar
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
- Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Lene Simonsen
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Charlotte M Sorensen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sten Madsbad
- Department of Endocrinology, Hvidovre Hospital, University Hospital of Copenhagen, Hvidovre, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Peter Hovind
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Jens Bülow
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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6
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Andersen H, Hansen MH, Buhl KB, Stæhr M, Friis UG, Enggaard C, Supramaniyam S, Lund IK, Svenningsen P, Hansen PBL, Jensen BL. Plasminogen Deficiency and Amiloride Mitigate Angiotensin II-Induced Hypertension in Type 1 Diabetic Mice Suggesting Effects Through the Epithelial Sodium Channel. J Am Heart Assoc 2020; 9:e016387. [PMID: 33215566 PMCID: PMC7763785 DOI: 10.1161/jaha.120.016387] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Diabetic nephropathy is a common diabetes mellitus complication associated with hypertension, proteinuria, and excretion of urinary plasmin that activates the epithelial sodium channel, ENaC, in vitro. Here we hypothesized that the deletion of plasminogen and amiloride treatment protect against hypertension in diabetes mellitus. Methods and Results Male plasminogen knockout (plasminogen-deficient [Plg-/-]) and wild-type mice were rendered diabetic with streptozotocin. Arterial blood pressure was recorded continuously by indwelling catheters before and during 10 days of angiotensin II infusion (ANGII; 30-60 ng/kg per minute). The effect of amiloride infusion (2 mg/kg per day, 4 days) was tested in wild-type, diabetic ANGII-treated mice. Streptozotocin increased plasma and urine glucose concentrations and 24-hour urine albumin and plasminogen excretion. Diabetic Plg-/- mice displayed larger baseline albuminuria and absence of urine plasminogen. Baseline mean arterial blood pressure did not differ between groups. Although ANGII elevated blood pressure in wild-type, diabetic wild-type, and Plg-/- control mice, ANGII did not change blood pressure in diabetic Plg-/- mice. Compared with ANGII infusion alone, wild-type ANGII-infused diabetic mice showed blood pressure reduction upon amiloride treatment. There was no difference in plasma renin, ANGII, aldosterone, tissue prorenin receptor, renal inflammation, and fibrosis between groups. Urine from wild-type mice evoked larger amiloride-sensitive current than urine from Plg-/- mice with or without diabetes mellitus. Full-length γ-ENaC and α-ENaC subunit abundances were not changed in kidney homogenates, but the 70 kDa γ-ENaC cleavage product was increased in diabetic versus nondiabetic mice. Conclusions Plasmin promotes hypertension in diabetes mellitus with albuminuria likely through the epithelial sodium channel.
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Affiliation(s)
- Henrik Andersen
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Maria Høj Hansen
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Kristian B Buhl
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Mette Stæhr
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Ulla G Friis
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Camilla Enggaard
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Shanya Supramaniyam
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Ida K Lund
- The Finsen Laboratory Copenhagen University Hospital, and Biotech Research and Innovation Center (BRIC) University of Copenhagen Denmark
| | - Per Svenningsen
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Pernille B L Hansen
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark.,Research and Early Development Cardiovascular, Renal and Metabolism BioPharmaceuticals R&D AstraZeneca Gothenburg Sweden
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
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Asmar A, Cramon PK, Asmar M, Simonsen L, Sorensen CM, Madsbad S, Moro C, Hartmann B, Rehfeld JF, Holst JJ, Hovind P, Jensen BL, Bülow J. Increased oral sodium chloride intake in humans amplifies selectively postprandial GLP-1 but not GIP, CCK, and gastrin in plasma. Physiol Rep 2020; 8:e14519. [PMID: 32770661 PMCID: PMC7413881 DOI: 10.14814/phy2.14519] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/03/2020] [Accepted: 07/03/2020] [Indexed: 12/24/2022] Open
Abstract
Human studies have demonstrated that physiologically relevant changes in circulating glucagon-like peptide-1 (GLP-1) elicit a rapid increase in renal sodium excretion when combined with expansion of the extracellular fluid volume. Other studies support the involvement of various gastrointestinal hormones, e.g., gastrin and cholecystokinin (CCK) in a gut-kidney axis, responsible for a rapid-acting feed-forward natriuretic mechanism. This study was designed to investigate the hypothesis that the postprandial GLP-1 plasma concentration is sensitive to the sodium content in the meal. Under fixed sodium intake for 4 days prior to each experimental day, 10 lean healthy male participants were examined twice in random order after a 12-hr fasting period. Arterial blood samples were collected at 10-20-min intervals for 140 min after 75 grams of oral glucose + 6 grams of oral sodium chloride (NaCl) load versus 75 grams of glucose alone. Twenty-four-hour baseline urinary sodium excretions were similar between study days. Arterial GLP-1 levels increased during both oral glucose loads and were significantly higher at the 40-80 min period during glucose + NaCl compared to glucose alone. The postprandial arterial responses of CCK, gastrin, and glucose-dependent insulinotropic polypeptide as well as glucose, insulin, and C-peptide did not differ between the two study days. Arterial renin, aldosterone, and natriuretic peptides levels did not change within subjects or between study days. Angiotensin II levels were significantly lower at the time GLP-1 was higher (60-80 min) during glucose + NaCl. Sodium intake in addition to a glucose load selectively amplifies the postprandial GLP-1 plasma concentration. Thus, GLP-1 may be part of an acute feed-forward mechanism for natriuresis.
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Affiliation(s)
- Ali Asmar
- Department of Clinical Physiology, Nuclear Medicine and PET, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Per K. Cramon
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Meena Asmar
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
- Department of EndocrinologyOdense University HospitalOdenseDenmark
| | - Lene Simonsen
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | | | - Sten Madsbad
- Department of EndocrinologyHvidovre HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Cedric Moro
- Institut National de la Santé et de la Recherche Médicale (Inserm) UMR 1048Institute of Metabolic and Cardiovascular DiseasesPaul Sabatier UniversityToulouseFrance
| | - Bolette Hartmann
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
- Novo Nordisk Foundation Center for Basic Metabolic ResearchUniversity of CopenhagenCopenhagenDenmark
| | - Jens F. Rehfeld
- Department of Clinical Biochemistry, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
| | - Jens J. Holst
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
- Novo Nordisk Foundation Center for Basic Metabolic ResearchUniversity of CopenhagenCopenhagenDenmark
| | - Peter Hovind
- Department of Clinical Physiology, Nuclear Medicine and PET, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Boye L. Jensen
- Department of Cardiovascular and Renal ResearchUniversity of Southern DenmarkOdenseDenmark
| | - Jens Bülow
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
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8
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Israelsen M, Dahl EK, Madsen BS, Wiese S, Bendtsen F, Møller S, Fialla AD, Jensen BL, Krag A. Dobutamine reverses the cardio-suppressive effects of terlipressin without improving renal function in cirrhosis and ascites: a randomized controlled trial. Am J Physiol Gastrointest Liver Physiol 2020; 318:G313-G321. [PMID: 31841026 DOI: 10.1152/ajpgi.00328.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Acute kidney injury and hepatorenal syndrome (HRS) are frequent complications in patients with cirrhosis and ascites. First-line treatment is terlipressin, which reverses HRS in ~40% of patients but also lowers cardiac output (CO). We aimed to investigate whether reversing the cardio-suppressive effect of terlipressin with the β-adrenoceptor agonist dobutamine would increase CO and thereby increase the glomerular filtration rate (GFR). We randomized 25 patients with cirrhosis, ascites, and impaired renal function (2:2:1): group A received terlipressin followed by the addition of dobutamine; group B received dobutamine and terlipressin as monotherapies; and group C received placebo. Renal and cardiac functions were assessed during 8 clearance periods of 30 min, and concentrations of vasoactive hormones were measured. Dobutamine as a monotherapy increased CO (1.03 L/min, P < 0.01) but had no significant effects on GFR. Renin (P < 0.05), angiotensin II (P < 0.005), and aldosterone (P < 0.05) increased after dobutamine infusion. Terlipressin as a monotherapy improved GFR (18.9 mL·min-1·m-2, P = 0.005) and mean arterial pressure (MAP) (14 mmHg, P = 0.001) but reduced CO (-0.92 L/min, P < 0.005) and renin (P < .005). A combined treatment of dobutamine and terlipressin had a positive effect on CO (1.19 L/min, P < 0.05) and increased renin (P < 0.005), angiotensin II (P < 0.005), and aldosterone (P < 0.05), but it had no significant effects on MAP or GFR. Dobutamine reversed the cardio-suppressive effect of terlipressin in cirrhosis, ascites, and impaired renal function. However, dobutamine reduced peripheral vascular resistance, activated renin-angiotensin-aldosterone system, and did not improve GFR compared with terlipressin as a monotherapy. Therefore, dobutamine cannot be recommended in cirrhosis and ascites.NEW & NOTEWORTHY This study shows that the cardio-suppressive effects of the vasopressin receptor agonist terlipressin can be reversed by dobutamine. This is a novel observation in patients with decompensated cirrhosis. Furthermore, we show that dobutamine reduced the peripheral vascular resistance and activated the renin-angiotensin system, whereas renal function was not further improved by terlipressin alone.
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Affiliation(s)
- Mads Israelsen
- Department of Gastroenterology and Hepatology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Emilie Kristine Dahl
- Department of Gastroenterology and Hepatology, Odense University Hospital, Odense, Denmark
| | - Bjørn Stæhr Madsen
- Department of Gastroenterology and Hepatology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Signe Wiese
- Gastro Unit, Copenhagen University Hospital Hvidovre, Denmark.,Center for Functional and Diagnostic Imaging and Research, Department of Clinical Physiology and Nuclear Medicine 260, Faculty of Health Sciences Hvidovre Hospital, University of Copenhagen, Denmark
| | | | - Søren Møller
- Center for Functional and Diagnostic Imaging and Research, Department of Clinical Physiology and Nuclear Medicine 260, Faculty of Health Sciences Hvidovre Hospital, University of Copenhagen, Denmark
| | - Annette Dam Fialla
- Department of Gastroenterology and Hepatology, Odense University Hospital, Odense, Denmark
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Aleksander Krag
- Department of Gastroenterology and Hepatology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
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9
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McArdle Z, Pontes RB, Yao ST, Lankadeva YR, Singh RR, Hood SG, Schlaich MP, May CN, Booth LC. Blunted diuretic and natriuretic responses to acute sodium loading early after catheter-based renal denervation in normotensive sheep. Am J Physiol Regul Integr Comp Physiol 2019; 317:R319-R327. [DOI: 10.1152/ajpregu.00228.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Catheter-based renal denervation (RDN) was introduced as a treatment for resistant hypertension. There remain critical questions regarding the physiological mechanisms underlying the hypotensive effects of catheter-based RDN. Previous studies indicate that surgical denervation reduces renin and the natriuretic response to saline loading; however, the effects on these variables of catheter-based RDN, which does not yield complete denervation, are largely unknown. The aim of this study was to investigate the effects of catheter-based RDN on glomerular-associated renin and regulation of fluid and sodium homeostasis in response to physiological challenges. First, immunohistochemical staining for renin was performed in normotensive sheep ( n = 6) and sheep at 1 wk ( n = 6), 5.5 mo ( n = 5), and 11 mo ( n = 5) after unilateral RDN using the same catheter used in patients (Symplicity). Following catheter-based RDN (1 wk), renin-positive glomeruli were significantly reduced compared with sham animals ( P < 0.005). This was sustained until 5.5 mo postdenervation. To determine whether the reduction in renin after 1 wk had physiological effects, in a separate cohort, Merino ewes were administered high and low saline loads before and 1 wk after bilateral RDN ( n = 9) or sham procedure ( n = 8). After RDN (1 wk), the diuretic response to a low saline load was significantly reduced ( P < 0.05), and both the diuretic and natriuretic responses to a high saline load were significantly attenuated ( P < 0.05). In conclusion, these findings indicate that catheter-based RDN acutely alters the ability of the kidney to regulate fluid and electrolyte balance. Further studies are required to determine the long-term effects of catheter-based RDN on renal sodium and water homeostasis.
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Affiliation(s)
- Zoe McArdle
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Roberto B. Pontes
- Cardiovascular Division, Department of Physiology, Federal University of São Paulo, São Paulo, Brazil
| | - Song T. Yao
- Faculty of Medicine, Dentistry and Health Sciences, Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Yugeesh R. Lankadeva
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Reetu R. Singh
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Sally G. Hood
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Markus P. Schlaich
- Dobney Hypertension Centre, School of Medicine-Royal Perth Hospital Unit, University of Western Australia, Perth, Australia
| | - Clive N. May
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Lindsea C. Booth
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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10
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Lindestam U, Fläring U, Almström M, Andersson A, Svensson JF, Malmquist P, Jacks J, Lönnqvist PA, Jensen BL, Carlström M, Krmar RT. Sodium and water homeostasis in children admitted with acute appendicitis: a prospective study. Pediatr Res 2019; 86:5-8. [PMID: 30812028 DOI: 10.1038/s41390-019-0353-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 02/04/2019] [Accepted: 02/17/2019] [Indexed: 01/11/2023]
Affiliation(s)
- Ulf Lindestam
- Department of Pediatric Perioperative Medicine and Intensive Care, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Physiology and Pharmacology (FYFA), Karolinska Institutet, Stockholm, Sweden
| | - Urban Fläring
- Department of Pediatric Perioperative Medicine and Intensive Care, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Physiology and Pharmacology (FYFA), Karolinska Institutet, Stockholm, Sweden
| | - Markus Almström
- Department of Paediatric Surgery, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Women´s and Children´s Health, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Andersson
- Department of Pediatric Perioperative Medicine and Intensive Care, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Physiology and Pharmacology (FYFA), Karolinska Institutet, Stockholm, Sweden
| | - Jan F Svensson
- Department of Paediatric Surgery, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Women´s and Children´s Health, Karolinska Institutet, Stockholm, Sweden
| | - Pia Malmquist
- Department of Pediatric Emergency Medicine, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Johannes Jacks
- Department of Pediatric Perioperative Medicine and Intensive Care, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Per-Arne Lönnqvist
- Department of Pediatric Perioperative Medicine and Intensive Care, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Physiology and Pharmacology (FYFA), Karolinska Institutet, Stockholm, Sweden
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Mattias Carlström
- Department of Physiology and Pharmacology (FYFA), Karolinska Institutet, Stockholm, Sweden
| | - Rafael T Krmar
- Department of Physiology and Pharmacology (FYFA), Karolinska Institutet, Stockholm, Sweden.
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11
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Asmar A, Cramon PK, Simonsen L, Asmar M, Sorensen CM, Madsbad S, Moro C, Hartmann B, Jensen BL, Holst JJ, Bülow J. Extracellular Fluid Volume Expansion Uncovers a Natriuretic Action of GLP-1: A Functional GLP-1-Renal Axis in Man. J Clin Endocrinol Metab 2019; 104:2509-2519. [PMID: 30835273 DOI: 10.1210/jc.2019-00004] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/27/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE We have previously demonstrated that glucagon-like peptide-1 (GLP-1) does not affect renal hemodynamics or function under baseline conditions in healthy participants and in patients with type 2 diabetes mellitus. However, it is possible that GLP-1 promotes natriuresis under conditions with addition of salt and water to the extracellular fluid. The current study was designed to investigate a possible GLP-1-renal axis, inducing natriuresis in healthy, volume-loaded participants. METHODS Under fixed sodium intake, eight healthy men were examined twice in random order during a 3-hour infusion of either GLP-1 (1.5 pmol/kg/min) or vehicle together with an intravenous infusion of 0.9% NaCl. Timed urine collections were conducted throughout the experiments. Renal plasma flow (RPF), glomerular filtration rate (GFR), and uptake and release of hormones and ions were measured via Fick's principle. RESULTS During GLP-1 infusion, urinary sodium and osmolar excretions increased significantly compared with vehicle. Plasma renin levels decreased similarly on both days, whereas angiotensin II (ANG II) levels decreased significantly only during GLP-1 infusion. RPF and GFR remained unchanged on both days. CONCLUSIONS In volume-loaded participants, GLP-1 induces natriuresis, probably brought about via a tubular mechanism secondary to suppression of ANG II, independent of renal hemodynamics, supporting the existence of a GLP-1-renal axis.
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Affiliation(s)
- Ali Asmar
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Per K Cramon
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Lene Simonsen
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Meena Asmar
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
- Department of Endocrinology, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Charlotte M Sorensen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sten Madsbad
- Department of Endocrinology, Hvidovre Hospital, University Hospital of Copenhagen, Hvidovre, Denmark
| | - Cedric Moro
- Institut National de la Santé et de la Recherche Médicale UMR 1048, Institute of Metabolic and Cardiovascular Diseases, and Paul Sabatier University, Toulouse, France
| | - Bolette Hartmann
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bülow
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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Ames MK, Atkins CE, Pitt B. The renin-angiotensin-aldosterone system and its suppression. J Vet Intern Med 2019; 33:363-382. [PMID: 30806496 PMCID: PMC6430926 DOI: 10.1111/jvim.15454] [Citation(s) in RCA: 222] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 01/30/2019] [Indexed: 12/11/2022] Open
Abstract
Chronic activation of the renin-angiotensin-aldosterone system (RAAS) promotes and perpetuates the syndromes of congestive heart failure, systemic hypertension, and chronic kidney disease. Excessive circulating and tissue angiotensin II (AngII) and aldosterone levels lead to a pro-fibrotic, -inflammatory, and -hypertrophic milieu that causes remodeling and dysfunction in cardiovascular and renal tissues. Understanding of the role of the RAAS in this abnormal pathologic remodeling has grown over the past few decades and numerous medical therapies aimed at suppressing the RAAS have been developed. Despite this, morbidity from these diseases remains high. Continued investigation into the complexities of the RAAS should help clinicians modulate (suppress or enhance) components of this system and improve quality of life and survival. This review focuses on updates in our understanding of the RAAS and the pathophysiology of AngII and aldosterone excess, reviewing what is known about its suppression in cardiovascular and renal diseases, especially in the cat and dog.
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Affiliation(s)
- Marisa K Ames
- Department of Clinical Sciences, College of Veterinary Medicine, Colorado State University, Fort Collins, Colorado
| | - Clarke E Atkins
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Bertram Pitt
- Department of Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
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13
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Bie P. Mechanisms of sodium balance: total body sodium, surrogate variables, and renal sodium excretion. Am J Physiol Regul Integr Comp Physiol 2018; 315:R945-R962. [DOI: 10.1152/ajpregu.00363.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The classical concepts of human sodium balance include 1) a total pool of Na+ of ≈4,200 mmol (total body sodium, TBS) distributed primarily in the extracellular fluid (ECV) and bone, 2) intake variations of 0.03 to ≈6 mmol·kg body mass−1·day−1, 3) asymptotic transitions between steady states with a halftime (T½) of 21 h, 4) changes in TBS driven by sodium intake measuring ≈1.3 day [ΔTBS/Δ(Na+ intake/day)], 5) adjustment of Na+ excretion to match any diet thus providing metabolic steady state, and 6) regulation of TBS via controlled excretion (90–95% renal) mediated by surrogate variables. The present focus areas include 1) uneven, nonosmotic distribution of increments in TBS primarily in “skin,” 2) long-term instability of TBS during constant Na+ intake, and 3) physiological regulation of renal Na+ excretion primarily by neurohumoral mechanisms dependent on ECV rather than arterial pressure. Under physiological conditions 1) the nonosmotic distribution of Na+ seems conceptually important, but quantitatively ill defined; 2) long-term variations in TBS represent significant deviations from steady state, but the importance is undetermined; and 3) the neurohumoral mechanisms of sodium homeostasis competing with pressure natriuresis are essential for systematic analysis of short-term and long-term regulation of TBS. Sodium homeostasis and blood pressure regulation are intimately related. Real progress is slow and will accelerate only through recognition of the present level of ignorance. Nonosmotic distribution of sodium, pressure natriuresis, and volume-mediated regulation of renal sodium excretion are essential intertwined concepts in need of clear definitions, conscious models, and future attention.
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Affiliation(s)
- Peter Bie
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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14
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Lankadeva YR, Evans RG, Kosaka J, Booth LC, Iguchi N, Bellomo R, May CN. Alterations in regional kidney oxygenation during expansion of extracellular fluid volume in conscious healthy sheep. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1242-R1250. [PMID: 30332304 DOI: 10.1152/ajpregu.00247.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Expansion of extracellular fluid volume with crystalloid solutions is a common medical intervention, but its effects on renal cortical and medullary oxygenation are poorly understood. Therefore, we instrumented sheep under general anesthesia to enable continuous measurement of systemic and renal hemodynamics, global renal oxygen delivery and consumption, and intrarenal tissue perfusion and oxygen tension (Po2) in conscious animals ( n = 7). The effects of three sequential intermittent infusions of 500 ml of compound sodium lactate solution, administered at hourly intervals, were determined. Volume expansion induced transient increases in mean arterial pressure (+7 ± 2%), central venous pressure (+50 ± 19%), and cardiac output (+15 ± 3%). There were sustained increases in renal medullary tissue Po2 (+35 ± 10%) despite increases in global renal oxygen consumption (+66 ± 18%) and renal oxygen extraction (+64 ± 8%). Volume expansion did not significantly alter renal blood flow, renal oxygen delivery, or medullary perfusion. The sustained increase in medullary Po2 was paralleled by increased bladder urine Po2 (34 ± 4%). Cortical perfusion and Po2 did not change significantly. Our findings indicate that extracellular fluid volume expansion can increase renal medullary oxygenation, providing a potential mechanistic basis for its use as prophylaxis against iatrogenic acute kidney injury. They also indicate that continuous measurement of bladder urine Po2 could be used to monitor the effects of volume expansion on medullary oxygenation. However, the mechanisms mediating increased medullary oxygenation during volume expansion remain to be determined.
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Affiliation(s)
- Yugeesh R Lankadeva
- Florey Institute of Neuroscience and Mental Health , Victoria , Australia.,Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne , Victoria , Australia
| | - Roger G Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University , Victoria , Australia
| | - Junko Kosaka
- Florey Institute of Neuroscience and Mental Health , Victoria , Australia
| | - Lindsea C Booth
- Florey Institute of Neuroscience and Mental Health , Victoria , Australia
| | - Naoya Iguchi
- Florey Institute of Neuroscience and Mental Health , Victoria , Australia
| | - Rinaldo Bellomo
- School of Medicine, University of Melbourne , Victoria , Australia
| | - Clive N May
- Florey Institute of Neuroscience and Mental Health , Victoria , Australia.,Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne , Victoria , Australia
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15
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Fialla AD, Schaffalitzky de Muckadell OB, Bie P, Thiesson HC. Activation of RAAS in a rat model of liver cirrhosis: no effect of losartan on renal sodium excretion. BMC Nephrol 2018; 19:238. [PMID: 30231858 PMCID: PMC6146747 DOI: 10.1186/s12882-018-1039-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 09/10/2018] [Indexed: 11/29/2022] Open
Abstract
Background Liver cirrhosis is characterized by avid sodium retention where the activation of the renin angiotensin aldosterone system (RAAS) is considered to be the hallmark of the sodium retaining mechanisms. The direct effect of angiotensin II (ANGII) on the AT-1 receptor in the proximal tubules is partly responsible for the sodium retention. The aim was to estimate the natriuretic and neurohumoral effects of an ANGII receptor antagonist (losartan) in the late phase of the disease in a rat model of liver cirrhosis. Methods Bile duct ligated (BDL) and sham operated rats received 2 weeks of treatment with losartan 4 mg/kg/day or placebo, given by gastric gavage 5 weeks after surgery. Daily sodium and potassium intakes and renal excretions were measured. Results The renal sodium excretion decreased in the BDL animals and this was not affected by losartan treatment. At baseline the plasma renin concentration (PRC) was similar in sham and BDL animals, but increased urinary excretion of ANGII and an increase P-Aldosterone was observed in the placebo treated BDL animals. The PRC was more than 150 times higher in the losartan treated BDL animals (p < 0.001) which indicated hemodynamic impairment. Conclusions Losartan 4 mg/kg/day did not increase renal sodium excretion in this model of liver cirrhosis, although the urinary ANGII excretion was increased. The BDL animals tolerated Losartan poorly, and the treatment induced a 150 times higher PRC.
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Affiliation(s)
- A D Fialla
- Department of Gastroenterology and Hepatology, Odense University Hospital, Sdr Boulevard, 5000 Odense C 29, Odense, Denmark.
| | - O B Schaffalitzky de Muckadell
- Department of Gastroenterology and Hepatology, Odense University Hospital, Sdr Boulevard, 5000 Odense C 29, Odense, Denmark
| | - P Bie
- Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - H C Thiesson
- Department of Nephrology, Odense University Hospital, Odense, Denmark
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16
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Zachar R, Al-Mashhadi A, Dimke H, Svenningsen P, Jensen BL, Carlström M. Hydronephrosis is associated with elevated plasmin in urine in pediatric patients and rats and changes in NCC and γ-ENaC abundance in rat kidney. Am J Physiol Renal Physiol 2018; 315:F547-F557. [DOI: 10.1152/ajprenal.00635.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Obstruction of urine flow at the level of the pelvo-ureteric junction (UPJO) and subsequent development of hydronephrosis is one of the most common congenital renal malformations. UPJO is associated with development of salt-sensitive hypertension, which is set by the obstructed kidney, and with a stimulated renin-angiotensin-aldosterone system (RAAS) in rodent models. This study aimed at investigating the hypothesis that 1) in pediatric patients with UPJO the RAAS is activated before surgical relief of the obstruction; 2) in rats with UPJO the RAAS activation is reflected by increased abundance of renal aldosterone-stimulated Na transporters; and 3) the injured UPJO kidney allows aberrant filtration of plasminogen, leading to proteolytic activation of the epithelial Na channel γ-subunit (γ-ENaC). Hydronephrosis resulting from UPJO in pediatric patients and rats was associated with increased urinary plasminogen-to-creatinine ratio. In pediatric patients, plasma renin, angiotensin II, urine and plasma aldosterone, and urine soluble prorenin receptor did not differ significantly before or after surgery, or compared with controls. Increased plasmin-to-plasminogen ratio was seen in UPJO rats. Intact γ-ENaC abundance was not changed in UPJO kidney, whereas low-molecular cleavage product abundance increased. The Na-Cl cotransporter displayed significantly lower abundance in the UPJO kidney compared with the nonobstructed contralateral kidney. The Na-K-ATPase α-subunit was unaltered. Treatment with an angiotensin-converting enzyme inhibitor (8 days, captopril) significantly lowered blood pressure in UPJO rats. It is concluded that the RAAS contributes to hypertension following partial obstruction of urine flow at the pelvo-ureteric junction with potential contribution from proteolytic activation of ENaC.
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Affiliation(s)
- Rikke Zachar
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Ammar Al-Mashhadi
- Pediatric Surgery Section, Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Per Svenningsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Boye L. Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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17
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Mahmoud MM, Shamseldeen AM, Rashed LA, Fares AE, Shamaa A, Gharib DM. Contribution of volume overload to progression of cardiovascular disease in a rat model of chronic kidney disease. Can J Physiol Pharmacol 2018; 96:1197-1208. [PMID: 30079760 DOI: 10.1139/cjpp-2018-0070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Volume overload is a common phenomenon in patients with chronic kidney disease that is associated with cardiovascular risk factors. However, its contribution to the development of adverse cardiovascular outcomes in those patients is not fully understood. Thus, the present work investigated the effect of salt-induced volume overload on cardiac functions and geometry in a rat model of chronic kidney disease. Thirty adult male Sprague-Dawley rats were randomly divided. One set of animals received a sham operation, while another set of animals underwent uninephrectomy. Rats were then fed either a normal-salt (0.4%) or high-salt (8.0%) diet for 6 weeks. The salt-loaded, uninephrectomized rats were treated with indapamide (3 mg·kg-1·day-1, orally) for 6 weeks. We found that uninephrectomized rats subjected to a high-salt diet (8.0%) for 6 weeks presented with hypertension, proteinuria, decreased renal Klotho expression, and deterioration in cardiac hemodynamics and histology. Echocardiography to assess cardiac function showed that ejection fraction and fractional shortening were positively correlated with relative renal Klotho expression. In conclusion, salt-induced volume overload in a rat model of chronic kidney disease has an adverse cardiovascular outcome and is associated with inflammatory activation and decrease in renal Klotho expression.
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Affiliation(s)
| | | | - Laila Ahmed Rashed
- b Department of Biochemistry, Faculty of Medicine, Cairo University, Egypt
| | - Amal Elham Fares
- c Department of Medical Histology, Faculty of Medicine, Cairo University, Egypt
| | - Ashraf Shamaa
- d Faculty of Veterinary Medicine, Cairo University, Egypt
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18
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Graugaard-Jensen C, Hvistendahl GM, Frøkiær J, Bie P, Djurhuus JC. Oral Contraceptives and Renal Water Handling: A diurnal study in young women. Physiol Rep 2018; 5:5/23/e13547. [PMID: 29233909 PMCID: PMC5727291 DOI: 10.14814/phy2.13547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 11/17/2017] [Accepted: 11/21/2017] [Indexed: 11/24/2022] Open
Abstract
To test the hypothesis that use of oral contraceptives (OC) changes diurnal variation in fluid balance mechanisms including blood pressure, secretion of vasopressin and oxytocin, and renal water and electrolyte excretion. Fifteen naturally cycling (NC) women in mid‐follicular phase and 11 long‐term OC users were included in a 24‐h standardized inpatient study for measurements of vasopressin, oxytocin, sodium, and osmolality in plasma as well as urinary excretion of electrolytes, aquaporin‐2, and prostaglandin E2. Blood pressure and heart rate were monitored noninvasively. Plasma vasopressin showed circadian rhythm (P = 0.02) and were similar in both groups (P = 0.18) including nighttime increases (P < 0.001). There was no circadian rhythm in plasma oxytocin within (P = 0.84) or between groups (P = 0.22). OC users had significantly lower plasma osmolality (Δosm: 3.05 ± 0.29 mosm/kg, P = 0.04) and lower plasma sodium (ΔNa+: 0.91 ± 0.09 mmol/l, P = 0.05). The two groups showed similar nighttime decreases in diuresis (1.08 ± 0.04 mL/(kg·h), P < 0.001) and increases in urine osmolality (109 ± 9 mosm/kg, P = 0.02), but similar rates of excretion of Aquaporin‐2, prostaglandin E2 and sodium. Nighttime decreases in mean arterial pressure of approximately 13% were significant in both groups (P < 0.001), but 24‐h average mean arterial pressure was significantly higher in OC users than in controls (+4.7 ± 0.4 mmHg, P = 0.02). Packed cell volumes were similar between groups (P = 0.54). OC does not change the diurnal patterns of renal fluid excretion, but resets the osmoreceptors for vasopressin release and leads to a significant increase in arterial blood pressure.
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Affiliation(s)
| | | | - Jørgen Frøkiær
- Department of Clinical Physiology and Nuclear Medicine, University Hospital of Aarhus, Aarhus N, Denmark
| | - Peter Bie
- Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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Gasthuys E, Vermeulen A, Croubels S, Millecam J, Schauvliege S, van Bergen T, De Bruyne P, Vande Walle J, Devreese M. Population Pharmacokinetic Modeling of a Desmopressin Oral Lyophilisate in Growing Piglets as a Model for the Pediatric Population. Front Pharmacol 2018; 9:41. [PMID: 29445339 PMCID: PMC5797931 DOI: 10.3389/fphar.2018.00041] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/15/2018] [Indexed: 11/25/2022] Open
Abstract
Desmopressin is used to treat primary nocturnal enuresis in children. Over the years, various formulations of desmopressin were commercialized of which the sublingual melt tablet is preferred in the pediatric population, despite the lack of full PK studies in this population. A full PK study was performed in growing conventional piglets to evaluate if this juvenile animal model can provide supplementary information to complement the information gap in the pediatric population. A desmopressin sublingual melt tablet (120 μg) was administered to 32 male piglets aged 8 days, 4 weeks, 7 weeks, and 6 months (each group n = 8). Population PK (pop-PK) analysis was performed to derive the PK parameters, the between- and within-subject variabilities and the effects of covariates. Desmopressin demonstrated two-compartmental PK, with a dual, sequential absorption process, and linear elimination. Body weight was the only significant covariate on clearance and on apparent volume of distribution of the central compartment. In human pediatric trials, no double peak in the absorption phase was observed in the plasma concentration-time curves, possibly due to the sparse sampling strategy applied in those pediatric studies. Therefore, it is recommended to perform additional studies, based on the sampling protocol applied in the current study.
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Affiliation(s)
- Elke Gasthuys
- Department of Pharmacology, Toxicology and Biochemistry, Ghent University, Merelbeke, Belgium
| | - An Vermeulen
- Department of Bio-analysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - Siska Croubels
- Department of Pharmacology, Toxicology and Biochemistry, Ghent University, Merelbeke, Belgium
| | - Joske Millecam
- Department of Pharmacology, Toxicology and Biochemistry, Ghent University, Merelbeke, Belgium
| | - Stijn Schauvliege
- Department of Surgery and Anesthesiology of Domestic Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Thomas van Bergen
- Department of Surgery and Anesthesiology of Domestic Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Pauline De Bruyne
- Department of Pediatrics and Medical Genetics, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Johan Vande Walle
- Department of Pediatrics and Medical Genetics, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Mathias Devreese
- Department of Pharmacology, Toxicology and Biochemistry, Ghent University, Merelbeke, Belgium
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Faerch M, Schroeder MK, Mahler BT, Christensen JH, Kamperis K, Rittig S. Determination of the renal concentration capacity following intravenous administration of dDAVP in healthy humans. Scandinavian Journal of Clinical and Laboratory Investigation 2018; 78:114-119. [PMID: 29361858 DOI: 10.1080/00365513.2017.1420215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The synthetic AVP analogue 1-desamino-8-d-arginine-vasopressin (dDAVP) is used for treatment of polyuric disorders. Lack of commercially available assays limits the usefulness of dDAVP as a diagnostic tool in the assessment of renal concentrating capacity. We aimed to develop a specific radioimmunoassay (RIA) for determination of plasma dDAVP (pdDAVP) in order to investigate the relationship between pdDAVP levels and urine osmolality (Uosm). Further, we aimed to determine the onset, duration, and maximum concentrating capacity following intravenous (i.v.) bolus dDAVP injection. The dDAVP assay was based on a well-established RIA for measurements of AVP. Fourteen healthy subjects (aged 15-18 years) participated. Blood and urine samples were collected prior to and after i.v. bolus of 0.03 µg/kg dDAVP. Diuresis and Uosm was measured for nine hours following dDAVP administration. PdDAVP and Uosm were analyzed.We established a specific RIA for the measurement of pdDAVP. All subjects reached maximal pdDAVP concentration (Cmax) 30 minutes following infusion, and a rise in Uosm after 60 minutes. Maximal Uosm varied between subjects, with no direct correlation to the achieved pdDAVP levels. We found no significant intra-individual variation between two dDAVP infusions and the effect was reproducible in terms of Cmax and maximal Uosm. We characterized the relationship between pdDAVP and Uosm after dDAVP bolus injection in healthy adolescents using our dDAVP assay. Maximal Uosm achieved correlated with the baseline Uosm levels and seemed unrelated to achieved pdDAVP levels. The urine concentrating response was maintained at least eight hours.
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Affiliation(s)
- Mia Faerch
- a Department of Pediatrics , Aarhus University Hospital , Aarhus , Denmark
| | - Marie K Schroeder
- b Pediatric Research Laboratory , Aarhus University Hospital , Aarhus , Denmark
| | - Birgitte T Mahler
- a Department of Pediatrics , Aarhus University Hospital , Aarhus , Denmark
| | - Jane H Christensen
- b Pediatric Research Laboratory , Aarhus University Hospital , Aarhus , Denmark.,c Department of Biomedicine , Aarhus University , Aarhus , Denmark
| | | | - Soren Rittig
- a Department of Pediatrics , Aarhus University Hospital , Aarhus , Denmark
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Wintmo P, Johansen SH, Hansen PBL, Lindholt JS, Urbonavicius S, Rasmussen LM, Bie P, Jensen BL, Stubbe J. The water channel AQP1 is expressed in human atherosclerotic vascular lesions and AQP1 deficiency augments angiotensin II-induced atherosclerosis in mice. Acta Physiol (Oxf) 2017; 220:446-460. [PMID: 28129470 DOI: 10.1111/apha.12853] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/29/2016] [Accepted: 01/22/2017] [Indexed: 12/22/2022]
Abstract
AIM The water channel aquaporin 1 (AQP1) promotes endothelial cell migration. It was hypothesized that AQP1 promotes neovascularization and growth of atherosclerotic plaques. METHODS AQP1 immunoreactivity and protein abundance was examined in human and murine atherosclerotic lesions and aortic aneurysms. Apolipoprotein E (ApoE) knockout (-/-) and AQP1-/-ApoE-/- mice were developed and fed Western diet (WD) for 8 and 16 weeks to accelerate the atherosclerosis process. In ApoE-/- and AQP1-/-ApoE-/- mice abdominal aortic aneurysms (AAA) were induced by angiotensin II (ANGII) infusion by osmotic minipumps for 4 weeks. RESULTS In human atherosclerotic lesions and AAA, AQP1 immunoreactive protein was associated with intralesional small vessels. In ApoE-/- mouse aorta, APQ1 mRNA levels were increased with time on WD (n = 7-9, P < 0.003). Both in murine lesions at the aortic root and in the abdominal aortic aneurysmal wall, AQP1 immunoreactivity was associated with microvascular structures. The atherosclerotic lesion burden was enhanced significantly in ANGII-infused AQP1-/-ApoE-/- mice compared with ApoE-/- mice, but neither incidence nor progression of AAA was different. The aortic lesion burden increased with time on WD but was not different between ApoE-/- and AQP1-/-ApoE-/- mice at either 8 or 16 weeks (n = 13-15). Baseline blood pressure and ANGII-induced hypertension were not different between genotypes. CONCLUSION AQP1 is expressed in atherosclerotic lesion neovasculature in human and mouse arteries and AQP1 deficiency augments lesion development in ANGII-promoted atherosclerosis in mice. Normal function of AQP1 affords cardiovascular protection.
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Affiliation(s)
- P. Wintmo
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - S. H. Johansen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - P. B. L. Hansen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - J. S. Lindholt
- Department of Cardiothoracic and Vascular Surgery T; University Hospital of Odense; Odense C Denmark
| | - S. Urbonavicius
- Cardiovascular Research Centre; Viborg Hospital; Viborg Denmark
| | - L. M. Rasmussen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
- Department of Clinical Biochemistry and Pharmacology; Odense University Hospital; Odense C Denmark
| | - P. Bie
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - B. L. Jensen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - J. Stubbe
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
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Fialla AD, Thiesson HC, Bie P, Schaffalitzky de Muckadell OB, Krag A. Internal dysregulation of the renin system in patients with stable liver cirrhosis. Scandinavian Journal of Clinical and Laboratory Investigation 2017; 77:298-309. [DOI: 10.1080/00365513.2017.1308546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Irsik DL, Blazer-Yost BL, Staruschenko A, Brands MW. The normal increase in insulin after a meal may be required to prevent postprandial renal sodium and volume losses. Am J Physiol Regul Integr Comp Physiol 2017; 312:R965-R972. [PMID: 28330966 DOI: 10.1152/ajpregu.00354.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 03/15/2017] [Accepted: 03/15/2017] [Indexed: 12/22/2022]
Abstract
Despite the effects of insulinopenia in type 1 diabetes and evidence that insulin stimulates multiple renal sodium transporters, it is not known whether normal variation in plasma insulin regulates sodium homeostasis physiologically. This study tested whether the normal postprandial increase in plasma insulin significantly attenuates renal sodium and volume losses. Rats were instrumented with chronic artery and vein catheters, housed in metabolic cages, and connected to hydraulic swivels. Measurements of urine volume and sodium excretion (UNaV) over 24 h and the 4-h postprandial period were made in control (C) rats and insulin-clamped (IC) rats in which the postprandial increase in insulin was prevented. Twenty-four-hour urine volume (36 ± 3 vs. 15 ± 2 ml/day) and UNaV (3.0 ± 0.2 vs. 2.5 ± 0.2 mmol/day) were greater in the IC compared with C rats, respectively. Four hours after rats were given a gel meal, blood glucose and urine volume were greater in IC rats, but UNaV decreased. To simulate a meal while controlling blood glucose, C and IC rats received a glucose bolus that yielded peak increases in blood glucose that were not different between groups. Urine volume (9.7 ± 0.7 vs. 6.0 ± 0.8 ml/4 h) and UNaV (0.50 ± 0.08 vs. 0.20 ± 0.06 mmol/4 h) were greater in the IC vs. C rats, respectively, over the 4-h test. These data demonstrate that the normal increase in circulating insulin in response to hyperglycemia may be required to prevent excessive renal sodium and volume losses and suggest that insulin may be a physiological regulator of sodium balance.
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Affiliation(s)
- Debra L Irsik
- Department of Physiology, Medical College of Georgia, Augusta, Georgia
| | - Bonnie L Blazer-Yost
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana; and
| | | | - Michael W Brands
- Department of Physiology, Medical College of Georgia, Augusta, Georgia;
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Nielsen LH, Ovesen P, Hansen MR, Brantlov S, Jespersen B, Bie P, Jensen BL. Changes in the renin-angiotensin-aldosterone system in response to dietary salt intake in normal and hypertensive pregnancy. A randomized trial. ACTA ACUST UNITED AC 2016; 10:881-890.e4. [DOI: 10.1016/j.jash.2016.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 08/29/2016] [Accepted: 10/09/2016] [Indexed: 12/31/2022]
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25
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Chronobiology and Pharmacologic Modulation of the Renin–Angiotensin–Aldosterone System in Dogs: What Have We Learned? Rev Physiol Biochem Pharmacol 2015; 169:43-69. [DOI: 10.1007/112_2015_27] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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26
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Graugaard-Jensen C, Hvistendahl GM, Frøkiaer J, Bie P, Djurhuus JC. Urinary concentration does not exclusively rely on plasma vasopressin. A study between genders. Gender and diurnal urine regulation. Acta Physiol (Oxf) 2014; 212:97-105. [PMID: 24965868 DOI: 10.1111/apha.12337] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 05/02/2014] [Accepted: 06/20/2014] [Indexed: 11/29/2022]
Abstract
AIM We investigated the influence of gender on the diurnal regulation of urine production with special focus on vasopressin, oxytocin and prostaglandin E2. METHODS Fifteen young women in mid-follicular phase and 22 young men (20-33 years) were included. All participants underwent a 24-h circadian inpatient study under standardized conditions for measurements of plasma vasopressin, oxytocin, sodium and osmolality. Urine was fractionally collected for measurements of electrolytes, aquaporin-2 and prostaglandin E2. RESULTS Plasma vasopressin expressed a diurnal rhythm with a night-time increase in both genders (P < 0.001). The ratio between mean daytime and mean night-time was 1.57 [95% CI: 1.33-1.84] P < 0.001 in men and 1.35 [95% CI: 1.11-1.64] P = 0.002 in women. P-vasopressin was higher in males during the night (P < 0.05). There was no difference in diuresis (P = 0.43), urine osmolality (P = 0.12) or aquaporin-2 excretion (P = 0.80) between genders. We found a trend towards a higher reabsorption of free water in males (P = 0.07). The excretion of prostaglandin E2 was higher in males (P < 0.001). There was no diurnal rhythm in p-oxytocin (P = 0.37) and no correlation to diuresis, urine osmolality or aquaporin-2 excretions. CONCLUSION Similar urinary flows and osmolalities are associated with levels of plasma vasopressin and renal PGE2, which are higher in males than in females. Oxytocin does not seem to play a role in the diurnal urine formation, whereas prostaglandin E2 could represent a mediator of the gender difference, not only as a mediator of the vasopressin response, but also as an independent factor. These findings need further elucidation.
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Affiliation(s)
- C. Graugaard-Jensen
- Department of Urology; Skejby Section; University Hospital of Aarhus; Aarhus N Denmark
| | - G. M. Hvistendahl
- Department of Urology; Skejby Section; University Hospital of Aarhus; Aarhus N Denmark
| | - J. Frøkiaer
- Department of Clinical Physiology and Nuclear Medicine; University Hospital of Aarhus; Skejby Section; Aarhus N Denmark
| | - P. Bie
- Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - J. C. Djurhuus
- The Institute of Clinical Medicine; Skejby Section; University Hospital of Aarhus; Aarhus N Denmark
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Mahler B, Kamperis K, Ankarberg-Lindgren C, Frøkiær J, Djurhuus JC, Rittig S. Puberty alters renal water handling. Am J Physiol Renal Physiol 2013; 305:F1728-35. [PMID: 24173356 DOI: 10.1152/ajprenal.00283.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the influence of sex and puberty stage on circadian urine production and levels of antidiuretic hormone [arginine vasopressin (AVP)] in healthy children. Thirty-nine volunteers (9 prepuberty boys, 10 prepuberty girls, 10 midpuberty boys, and 10 midpuberty girls) were included. All participants underwent a 24-h circadian inpatient study under standardized conditions regarding Na(+) and fluid intake. Blood samples were drawn every 4 h for measurements of plasma AVP, serum 17-β-estradiol, and testosterone, and urine was fractionally collected for measurements of electrolytes, aquaporin (AQP)2, and PGE2. We found a marked nighttime decrease in diuresis (from 1.69 ± 0.08 to 0.86 ± 0.06 ml·kg(-1)·h(-1), P < 0.001) caused by a significant nighttime increase in solute-free water reabsorption (TcH2O; day-to-night ratio: 0.64 ± 0.07, P < 0.001) concurrent with a significant decrease in osmotic excretion (day-to-night ratio: 1.23 ± 0.06, P < 0.001). Plasma AVP expressed a circadian rhythm (P < 0.01) with a nighttime increase and peak levels at midnight (0.49 ± 0.05 pg/ml). The circadian plasma AVP rhythm was not influenced by sex (P = 0.56) or puberty stage (P = 0.73). There was significantly higher nighttime TcH2O in prepuberty children. This concurred with increased nighttime urinary AQP2 excretion in prepuberty children. Urinary PGE2 exhibited a circadian rhythm independent of sex or puberty stage. Levels of serum 17β-estradiol and testosterone were as expected for sex and puberty stage, and no effect on the AVP-AQP2-TcH2O axis was observed. This study found a circadian rhythm of plasma AVP independent of sex and puberty stage, although nighttime TcH2O was higher and AQP2 excretion was more pronounced in prepuberty children, suggesting higher prepuberty renal AVP sensitivity.
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Affiliation(s)
- B Mahler
- Dept. of Pediatrics, Regionshospitalet Randers, Skovlyvej 1, Randers 8930, Denmark.
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McMahon EJ, Bauer JD, Hawley CM, Isbel NM, Stowasser M, Johnson DW, Campbell KL. A randomized trial of dietary sodium restriction in CKD. J Am Soc Nephrol 2013; 24:2096-103. [PMID: 24204003 DOI: 10.1681/asn.2013030285] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
There is a paucity of quality evidence regarding the effects of sodium restriction in patients with CKD, particularly in patients with pre-end stage CKD, where controlling modifiable risk factors may be especially important for delaying CKD progression and cardiovascular events. We conducted a double-blind placebo-controlled randomized crossover trial assessing the effects of high versus low sodium intake on ambulatory BP, 24-hour protein and albumin excretion, fluid status (body composition monitor), renin and aldosterone levels, and arterial stiffness (pulse wave velocity and augmentation index) in 20 adult patients with hypertensive stage 3-4 CKD as phase 1 of the LowSALT CKD study. Overall, salt restriction resulted in statistically significant and clinically important reductions in BP (mean reduction of systolic/diastolic BP, 10/4 mm Hg; 95% confidence interval, 5 to 15 /1 to 6 mm Hg), extracellular fluid volume, albuminuria, and proteinuria in patients with moderate-to-severe CKD. The magnitude of change was more pronounced than the magnitude reported in patients without CKD, suggesting that patients with CKD are particularly salt sensitive. Although studies with longer intervention times and larger sample sizes are needed to confirm these benefits, this study indicates that sodium restriction should be emphasized in the management of patients with CKD as a means to reduce cardiovascular risk and risk for CKD progression.
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Mochel JP, Fink M, Peyrou M, Desevaux C, Deurinck M, Giraudel JM, Danhof M. Chronobiology of the renin-angiotensin-aldosterone system in dogs: relation to blood pressure and renal physiology. Chronobiol Int 2013; 30:1144-59. [DOI: 10.3109/07420528.2013.807275] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Lankadeva YR, Singh RR, Hilliard LM, Moritz KM, Denton KM. Blunted sodium excretion in response to a saline load in 5 year old female sheep following fetal uninephrectomy. PLoS One 2012; 7:e47528. [PMID: 23077628 PMCID: PMC3471853 DOI: 10.1371/journal.pone.0047528] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 09/12/2012] [Indexed: 01/14/2023] Open
Abstract
Previously, we have shown that fetal uninephrectomy (uni-x) causes hypertension in female sheep by 2 years of age. Whilst the hypertension was not exacerbated by 5 years of age, these uni-x sheep had greater reductions in renal blood flow (RBF). To further explore these early indications of a decline in renal function, we investigated the renal response to a saline load (25 ml/kg/40 min) in 5-year old female uni-x and sham sheep. Basal mean arterial pressure was ∼15 mmHg greater (P(Group)<0.001), and sodium excretion (∼50%), glomerular filtration rate (∼30%, GFR) and RBF (∼40%) were all significantly lower (P(Group)<0.01) in uni-x compared to sham animals. In response to saline loading, sodium excretion increased significantly in both groups (P(Time)<0.001), however this response was blunted in uni-x sheep (P(GroupxTime)<0.01). This was accompanied with an attenuated increase in GFR and fractional sodium excretion (both P(GroupxTime)<0.05), and reduced activation of the renin-angiotensin system (both P<0.05), as compared to the sham group. The reduction in sodium excretion was associated with up-regulations in the renal gene expression of NHE3 and Na(+)/K(+) ATPase α and β subunits in the kidney cortex of the uni-x compared to the sham animals (P<0.05). Notably, neither group completely excreted the saline load within the recovery period, but the uni-x retained a higher percentage of the total volume (uni-x: 48±7%; sham: 22±9%, P<0.05). In conclusion, a reduced ability to efficiently regulate extracellular fluid homeostasis is evident in female sheep at 5 years of age, which was exacerbated in animals born with a congenital nephron deficit. Whilst there was no overt exacerbation of hypertension and renal insufficiency with age in the uni-x sheep, these animals may be more vulnerable to secondary renal insults.
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Affiliation(s)
| | - Reetu R. Singh
- Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | | | - Karen M. Moritz
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | - Kate M. Denton
- Department of Physiology, Monash University, Victoria, Australia
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Damkjaer M, Vafaee M, Braad PE, Petersen H, Høilund-Carlsen PF, Bie P. Renal cortical and medullary blood flow during modest saline loading in humans. Acta Physiol (Oxf) 2012; 205:472-83. [PMID: 22433079 DOI: 10.1111/j.1748-1716.2012.02436.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 01/05/2012] [Accepted: 03/13/2012] [Indexed: 02/02/2023]
Abstract
AIM Renal medullary blood flow (RMBF) is considered an important element of sodium homeostasis, but the experimental evidence is incongruent. Studies in anaesthetized animals generally support the concept in contrast to measurements in conscious animals. We hypothesized that saline-induced natriuresis is associated with changes in RMBF in humans. METHODS After 4 days of low-sodium diet, healthy men were subjected to slow intravenous saline loading (12 μmol kg(-1) min(-1)) for 4 h. Renal medullary and cortical blood flow was determined by positron emission tomography with H(2)(15)O before and after saline infusion using two independent imaging processing methods. One based on a previously published algorithm (voxel peeling) and a novel method based on contrast-enhanced computed tomography (CT). Blood pressure was measured oscillometrically every 10 min. Cardiac output, heart rate and total peripheral resistance were recorded continuously. RESULTS Saline loading increased the urinary sodium excretion by 3.6-fold (21-76 μmol min(-1) , P < 0.01). The RMBF was 2.6 ± 0.2 mL g(-1) tissue min(-1) before and 2.7 ± 0.1 mL g(-1) tissue min(-1) after saline (n.s.). Cortical blood flow was 3.6 ± 0.1 before and 3.4 ± 0.2 after saline (n.s.). Mean arterial blood pressure did not change measurably (90 vs. 90 mmHg). Bland-Altman analysis suggested agreement between results obtained with voxel peeling (2.6 ± 0.2 mL g(-1) tissue min(-1)) and contrast-enhanced CT (2.0 ± 0.1 mL g(-1) tissue min(-1)). CONCLUSION In normal humans, changes in RMBF are not necessarily involved in the natriuretic response to modest saline loading. This result is in line with data from conscious rodents.
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Affiliation(s)
- M. Damkjaer
- Institute of Molecular Medicine; University of Southern Denmark; Odense; Denmark
| | - M. Vafaee
- Department of Neuroscience and Pharmacology; Faculty of Health Sciences; University of Copenhagen; Copenhagen; Denmark
| | - P. E. Braad
- Department of Nuclear Medicine; Odense University Hospital; Odense; Denmark
| | - H. Petersen
- Department of Nuclear Medicine; Odense University Hospital; Odense; Denmark
| | | | - P. Bie
- Institute of Molecular Medicine; University of Southern Denmark; Odense; Denmark
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Mahler B, Kamperis K, Schroeder M, Frøkiær J, Djurhuus JC, Rittig S. Sleep deprivation induces excess diuresis and natriuresis in healthy children. Am J Physiol Renal Physiol 2012; 302:F236-43. [DOI: 10.1152/ajprenal.00283.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Urine production is reduced at night, allowing undisturbed sleep. This study was undertaken to show the effect of sleep deprivation (SD) on urine production in healthy children. Special focus was on gender and children at an age where enuresis is still prominent. Twenty healthy children (10 girls) underwent two 24-h studies, randomly assigned to either sleep or SD on the first study night. Diet and fluid intake were standardized. Blood samples were drawn every 4 h during daytime and every 2 h at night. Urine was fractionally collected. Blood pressure and heart rate were noninvasively monitored. Blood was analyzed for plasma antidiuretic hormone (AVP), atrial natriuretic peptide (ANP), angiotensin II, aldosterone, and renin. Urine was analyzed for aquaporin-2 and PGE2. Successful SD was achieved in all participants with a minimum of 4 h 50 min, and full-night SD was obtained in 50% of the participants. During SD, both boys and girls produced markedly larger amounts of urine than during normal sleep (477 ± 145 vs. 291 ± 86 ml, P < 0.01). SD increased urinary excretion of sodium (0.17 ± 0.05 vs. 0.10 ± 0.03 mmol·kg−1·h−1) whereas solute-free water reabsorption remained unchanged. SD induced a significant fall in nighttime plasma AVP ( P < 0.01), renin ( P < 0.05), angiotensin II ( P < 0.001), and aldosterone ( P < 0.05) whereas plasma ANP levels remained uninfluenced ( P = 0.807). Nighttime blood pressure and heart rate were significantly higher during SD (mean arterial pressure: 78.5 ± 8.0 vs. 74.7 ± 8.7 mmHg, P < 0.001). SD leads to natriuresis and excess diuresis in healthy children. The underlying mechanism could be a reduced nighttime dip in blood pressure and a decrease in renin-angiotensin-aldosterone system levels during sleep deprivation.
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Affiliation(s)
- B. Mahler
- Institute of Clinical Medicine,
- Department of Pediatrics,
| | | | | | - J. Frøkiær
- Department of Clinical Physiology, and
- Water and Salt Research Center, Aarhus University, Aarhus University Hospital, Skejby, Aarhus N, Denmark
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Nørregaard R, Madsen K, Hansen PBL, Bie P, Thavalingam S, Frøkiær J, Jensen BL. COX-2 disruption leads to increased central vasopressin stores and impaired urine concentrating ability in mice. Am J Physiol Renal Physiol 2011; 301:F1303-13. [PMID: 21880835 DOI: 10.1152/ajprenal.00665.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It was hypothesized that cyclooxygenase-2 (COX-2) activity promotes urine concentrating ability through stimulation of vasopressin (AVP) release after water deprivation (WD). COX-2-deficient (COX-2(-/-), C57BL/6) and wild-type (WT) mice were water deprived for 24 h, and water balance, central AVP mRNA and peptide level, AVP plasma concentration, and AVP-regulated renal transport protein abundances were measured. In male COX-2(-/-), basal urine output and water intake were elevated while urine osmolality was decreased compared with WT. Water deprivation resulted in lower urine osmolality, higher plasma osmolality in COX-2(-/-) mice irrespective of gender. Hypothalamic AVP mRNA level increased and was unchanged between COX-2(-/-) and WT after WD. AVP peptide content was higher in COX-2(-/-) compared with WT. At baseline, plasma AVP concentration was elevated in conscious chronically catheterized COX-2(-/-) mice, but after WD plasma AVP was unchanged between COX-2(-/-) and WT mice (43 ± 11 vs. 70 ± 16 pg/ml). Renal V2 receptor abundance was downregulated in COX-2(-/-) mice. Medullary interstitial osmolality increased and did not differ between COX-2(-/-) and WT after WD. Aquaporin-2 (AQP2; cortex-outer medulla), AQP3 (all regions), and UT-A1 (inner medulla) protein abundances were elevated in COX-2(-/-) at baseline and further increased after WD. COX-2(-/-) mice had elevated plasma urea and creatinine and accumulation of small subcapsular glomeruli. In conclusion, hypothalamic COX-2 activity is not necessary for enhanced AVP expression and secretion in response to water deprivation. Renal medullary COX-2 activity negatively regulates AQP2 and -3. The urine concentrating defect in COX-2(-/-) is likely caused by developmental glomerular injury and not dysregulation of AVP or collecting duct aquaporins.
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Affiliation(s)
- Rikke Nørregaard
- The Water and Salt Research Center, Institute of Clinical Medicine, University of Aarhus, Aarhus Univ. Hospital-Skejby, Brendstrupgaardsvej 100, Aarhus N, Denmark.
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Exaggerated natriuresis during clamping of systemic NO supply in healthy young men. Clin Sci (Lond) 2011; 122:63-73. [DOI: 10.1042/cs20110144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
NO (nitric oxide) may be involved in fluid homoeostasis. We hypothesized that increases in NO synthesis contribute to acute, saline-induced natriuresis, which, therefore, should be blunted when NO availability is stabilized. Young men were studied during simultaneous infusions of L-NAME [NG-nitro-L-arginine methyl ester; bolus of 750 μg·kg−1 of body weight and 8.3 μg·min−1·kg−1 of body weight] and SNP (sodium nitroprusside), the latter at a rate preventing L-NAME from increasing total peripheral resistance (‘NO-clamping’). Slow volume expansion (saline, 20 μmol of NaCl·min−1·kg−1 of body weight for 3 h) was performed with and without concomitant NO-clamping. NO-clamping itself decreased RPF (renal plasma flow; P~0.02) and tended to decrease arterial blood pressure [MABP (mean arterial blood pressure)]. Volume expansion markedly decreased the plasma levels of renin, AngII (angiotensin II) and aldosterone (all P<0.001), while MABP (oscillometry), heart rate, cardiac output (impedance cardiography), RPF (by p-aminohippurate), GFR [glomerular filtration rate; by using 51Cr-labelled EDTA] and plasma [Na+] and [K+] remained constant. Volume expansion increased sodium excretion (P<0.02) at constant filtered load, but more so during NO-clamping than during control (+184% compared with 52%; P<0.0001). Urinary nitrate/nitrite excretion increased during volume expansion; plasma cGMP and plasma vasopressin were unchanged. The results demonstrate that NO-clamping augments sodium excretion in response to volume expansion at constant MABP and GFR, reduced RPF and decreased renin system activity, a response termed hypernatriuresis. The results indicate that mediator(s) other than MABP, RPF, GFR and renin system activity contribute significantly to the homoeostatic response to saline loading, but the specific mechanisms of hypernatriuresis remain obscure.
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Møller S, Iversen JS, Krag A, Bie P, Kjaer A, Bendtsen F. Reduced baroreflex sensitivity and pulmonary dysfunction in alcoholic cirrhosis: effect of hyperoxia. Am J Physiol Gastrointest Liver Physiol 2010; 299:G784-90. [PMID: 20616307 DOI: 10.1152/ajpgi.00078.2010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Patients with cirrhosis exhibit impaired regulation of the arterial blood pressure, reduced baroreflex sensitivity (BRS), and prolonged QT interval. In addition, a considerable number of patients have a pulmonary dysfunction with hypoxemia, impaired lung diffusing capacity (Dl(CO)), and presence of hepatopulmonary syndrome (HPS). BRS is reduced at exposure to chronic hypoxia such as during sojourn in high altitudes. In this study, we assessed the relation of BRS to pulmonary dysfunction and cardiovascular characteristics and the effects of hyperoxia. Forty-three patients with cirrhosis and 12 healthy matched controls underwent hemodynamic and pulmonary investigations. BRS was assessed by cross-spectral analysis of variabilities between blood pressure and heart rate time series. A 100% oxygen test was performed with the assessment of arterial oxygen tensions (Pa(O(2))) and alveolar-arterial oxygen gradient. Baseline BRS was significantly reduced in the cirrhotic patients compared with the controls (4.7 +/- 0.8 vs. 10.3 +/- 2.0 ms/mmHg; P < 0.001). The frequency-corrected QT interval was significantly prolonged in the cirrhotic patients (P < 0.05). There was no significant difference in BRS according to presence of HPS, Pa(O(2)), Dl(CO), or Child-Turcotte score, but BRS correlated with metabolic and hemodynamic characteristics. After 100% oxygen inhalation, BRS and the QT interval remained unchanged in the cirrhotic patients. In conclusion, BRS is significantly reduced in patients with cirrhosis compared with controls, but it is unrelated to the degree of pulmonary dysfunction and portal hypertension. Acute hyperoxia does not significantly revert the low BRS or the prolonged QT interval in cirrhosis.
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Affiliation(s)
- Søren Møller
- Dept. of Clinical Physiology, Hvidovre Hospital, Denmark.
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Vigué B. [Hypernatremia in neurointensive care]. ACTA ACUST UNITED AC 2010; 29:e189-92. [PMID: 20650596 DOI: 10.1016/j.annfar.2010.06.009] [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: 11/17/2022]
Abstract
Hypernatremia invariably denotes hyperosmolarity and, at least transiently, causes cellular dehydration. Because of blood brain barrier properties, cerebral tissue volume is modified by acute changes in osmolarity. An acute hyperosmolarity (by intravenous sodium or mannitol) temporally decreases intracranial pressure. This treatment is thus useful in critical situations, allowing time for diagnosis and, if possible, other treatment. But in cases of sustained hypernatremia, cellular dehydration is rapidly counterbalanced by an increase in cellular osmolarity. For the brain, it has been shown that cerebral volume is restored in a few hours during prolonged hypernatremia. Moreover, the plasmatic osmotic load induces an increase in diuresis and natriuresis. A tight control is then necessary to prevent hypovolemia and electrolytes disorders. Teams using this treatment should undertake controlled randomized studies to ascertain any beneficial effect that cannot be explained by physiology.
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Affiliation(s)
- B Vigué
- Département d'anesthésie-réanimation, CHU de Bicêtre, AP-HP, Le Kremlin-Bicêtre, France.
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Castrop H, Höcherl K, Kurtz A, Schweda F, Todorov V, Wagner C. Physiology of Kidney Renin. Physiol Rev 2010; 90:607-73. [PMID: 20393195 DOI: 10.1152/physrev.00011.2009] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The protease renin is the key enzyme of the renin-angiotensin-aldosterone cascade, which is relevant under both physiological and pathophysiological settings. The kidney is the only organ capable of releasing enzymatically active renin. Although the characteristic juxtaglomerular position is the best known site of renin generation, renin-producing cells in the kidney can vary in number and localization. (Pro)renin gene transcription in these cells is controlled by a number of transcription factors, among which CREB is the best characterized. Pro-renin is stored in vesicles, activated to renin, and then released upon demand. The release of renin is under the control of the cAMP (stimulatory) and Ca2+(inhibitory) signaling pathways. Meanwhile, a great number of intrarenally generated or systemically acting factors have been identified that control the renin secretion directly at the level of renin-producing cells, by activating either of the signaling pathways mentioned above. The broad spectrum of biological actions of (pro)renin is mediated by receptors for (pro)renin, angiotensin II and angiotensin-( 1 – 7 ).
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Klaus Höcherl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Vladimir Todorov
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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Seeliger E, Lunenburg T, Ladwig M, Reinhardt HW. Role of the renin-angiotensin-aldosterone system for control of arterial blood pressure following moderate deficit in total body sodium: Balance studies in freely moving dogs. Clin Exp Pharmacol Physiol 2010; 37:e43-51. [DOI: 10.1111/j.1440-1681.2009.05332.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bie P, Damkjaer M. Renin secretion and total body sodium: Pathways of integrative control. Clin Exp Pharmacol Physiol 2010; 37:e34-42. [DOI: 10.1111/j.1440-1681.2009.05316.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kris-Etherton PM, Grieger JA, Hilpert KF, West SG. Milk products, dietary patterns and blood pressure management. J Am Coll Nutr 2009; 28 Suppl 1:103S-19S. [PMID: 19571168 DOI: 10.1080/07315724.2009.10719804] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
High blood pressure (BP) is a major risk factor for heart disease, stroke, congestive heart failure, and kidney disease. Inverse associations between dairy product consumption and systolic blood pressure (SBP) and diastolic blood pressure (DBP) have been observed in cross-sectional studies; some studies, however, have reported an inverse association with only one BP parameter, predominantly SBP. Randomized clinical trials examining the effect of calcium and the combination of calcium, potassium and magnesium provide evidence for causality. In these studies, reductions in BP were generally modest (-1.27 to -4.6 mmHg for SBP, and -0.24 to -3.8 mmHg for DBP). Dairy nutrients, most notably calcium, potassium and magnesium, have been shown to have a blood pressure lowering effect. A low calcium intake increases intracellular calcium concentrations which increases 1,25-dihydroxyvitamin D(3) and parathyroid hormone (PTH), causing calcium influx into vascular smooth muscle cells, resulting in greater vascular resistance. New research indicates that dairy peptides may act as angiotensin converting enzyme (ACE) inhibitors, thereby inhibiting the renin angiotensin system with consequent vasodilation. A growing evidence base shows that dairy product consumption is involved in the regulation of BP. Consequently, inclusion of dairy products in a heart healthy diet is an important focal point to attain BP benefits.
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Affiliation(s)
- Penny M Kris-Etherton
- Department of Nutritional Sciences, 110 Chandlee Laboratory, Penn State University, University Park, PA 16802, USA.
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Freitas RN, Khaw KT, Wu K, Bowman R, Jeffery H, Luben R, Wareham NJ, Bingham SA. A HMGCR polymorphism is associated with relations between blood pressure and urinary sodium and potassium ratio in the Epic-Norfolk Study. ACTA ACUST UNITED AC 2009; 3:238-44. [DOI: 10.1016/j.jash.2009.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 05/08/2009] [Accepted: 05/28/2009] [Indexed: 12/01/2022]
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Bie P, Mølstrøm S, Wamberg S. Normotensive sodium loading in conscious dogs: regulation of renin secretion during β-receptor blockade. Am J Physiol Regul Integr Comp Physiol 2009; 296:R428-35. [DOI: 10.1152/ajpregu.90753.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Renin secretion is regulated in part by renal nerves operating through β1-receptors of the renal juxtaglomerular cells. Slow sodium loading may decrease plasma renin concentration (PRC) and cause natriuresis at constant mean arterial blood pressure (MAP) and glomerular filtration rate (GFR). We hypothesized that in this setting, renin secretion and renin-dependent sodium excretion are controlled by via the renal nerves and therefore are eliminated or reduced by blocking the action of norepinephrine on the juxtaglomerular cells with the β1-receptor antagonist metoprolol. This was tested in conscious dogs by infusion of NaCl (20 μmol·kg−1·min−1for 180 min, NaLoad) during regular or low-sodium diet (0.03 mmol·kg−1·day−1, LowNa) with and without metoprolol (2 mg/kg plus 0.9 mg·kg−1·h−1). Vasopressin V2receptors were blocked by Otsuka compound OPC31260 to facilitate clearance measurements. Body fluid volume was maintained by servocontrolled fluid infusion. Metoprolol per se did not affect MAP, heart rate, or sodium excretion significantly, but reduced PRC and ANG II by 30–40%, increased plasma atrial natriuretic peptide (ANP), and tripled potassium excretion. LowNa per se increased PRC (+53%), ANG II (+93%), and aldosterone (+660%), and shifted the vasopressin function curve to the left. NaLoad elevated plasma [Na+] by 4.5% and vasopressin by threefold, but MAP and plasma ANP remained unchanged. NaLoad decreased PRC by ∼30%, ANG II by ∼40%, and aldosterone by ∼60%, regardless of diet and metoprolol. The natriuretic response to NaLoad was augmented during metoprolol regardless of diet. In conclusion, PRC depended on dietary sodium and β1-adrenergic control as expected; however, the acute sodium-driven decrease in PRC at constant MAP and GFR was unaffected by β1-receptor blockade demonstrating that renin may be regulated without changes in MAP, GFR, or β1-mediated effects of norepinephrine. Low-sodium diet augments vasopressin secretion, whereas ANP secretion is reduced.
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Abstract
Total body sodium and arterial blood pressure (ABP) are mutually dependent variables regulated by complex control systems. This review addresses the role of ABP in the normal control of sodium excretion (NaEx), and the physiological control of renin secretion. NaEx is a pivotal determinant of ABP, and under experimental conditions, ABP is a powerful, independent controller of NaEx. Blood volume is a function of dietary salt intake; however, ABP is not, at least not in steady states. A transient increase in ABP after a step-up in sodium intake could provide a causal relationship between ABP and the regulation of NaEx via a hypothetical integrative control system. However, recent data show that subtle sodium loading (simulating salty meals) causes robust natriuresis without changes in ABP. Changes in ABP are not necessary for natriuresis. Normal sodium excretion is not regulated by pressure. Plasma renin is log-linearly related to salt intake, and normally, decreases in renin secretion are a precondition of natriuresis after increases in total body sodium. Renin secretion is controlled by renal ABP, renal nerve activity and the tubular chloride concentrations at the macula densa (MD). Renal nerve activity is related to blood volume, also at constant ABP, and elevates renin secretion by means of beta(1)-adrenoceptors. Recent results indicate that renal denervation reduces ABP and renin activity, and that sodium loading may decrease renin without changes in ABP, glomerular filtration rate or beta(1)-mediated nerve activity. The latter indicates an essential role of the MD mechanism and/or a fourth mediator of the physiological control of renin secretion.
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Affiliation(s)
- P Bie
- Department of Physiology and Pharmacology, University of Southern Denmark, Odense, Denmark.
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Svenningsen P, Bistrup C, Friis UG, Bertog M, Haerteis S, Krueger B, Stubbe J, Jensen ON, Thiesson HC, Uhrenholt TR, Jespersen B, Jensen BL, Korbmacher C, Skøtt O. Plasmin in nephrotic urine activates the epithelial sodium channel. J Am Soc Nephrol 2008; 20:299-310. [PMID: 19073825 DOI: 10.1681/asn.2008040364] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Proteinuria and increased renal reabsorption of NaCl characterize the nephrotic syndrome. Here, we show that protein-rich urine from nephrotic rats and from patients with nephrotic syndrome activate the epithelial sodium channel (ENaC) in cultured M-1 mouse collecting duct cells and in Xenopus laevis oocytes heterologously expressing ENaC. The activation depended on urinary serine protease activity. We identified plasmin as a urinary serine protease by matrix-assisted laser desorption/ionization time of-flight mass spectrometry. Purified plasmin activated ENaC currents, and inhibitors of plasmin abolished urinary protease activity and the ability to activate ENaC. In nephrotic syndrome, tubular urokinase-type plasminogen activator likely converts filtered plasminogen to plasmin. Consistent with this, the combined application of urokinase-type plasminogen activator and plasminogen stimulated amiloride-sensitive transepithelial sodium transport in M-1 cells and increased amiloride-sensitive whole-cell currents in Xenopus laevis oocytes heterologously expressing ENaC. Activation of ENaC by plasmin involved cleavage and release of an inhibitory peptide from the ENaC gamma subunit ectodomain. These data suggest that a defective glomerular filtration barrier allows passage of proteolytic enzymes that have the ability to activate ENaC.
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Affiliation(s)
- Per Svenningsen
- Physiology and Pharmacology, Institute of Medical Biology, University of Southern Denmark, Odense C
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Svenningsen P, Bistrup C, Friis UG, Bertog M, Haerteis S, Krueger B, Stubbe J, Jensen ON, Thiesson HC, Uhrenholt TR, Jespersen B, Jensen BL, Korbmacher C, Skøtt O. Plasmin in nephrotic urine activates the epithelial sodium channel. J Am Soc Nephrol 2008. [PMID: 19073825 DOI: 10.11881/asn.2008040364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Proteinuria and increased renal reabsorption of NaCl characterize the nephrotic syndrome. Here, we show that protein-rich urine from nephrotic rats and from patients with nephrotic syndrome activate the epithelial sodium channel (ENaC) in cultured M-1 mouse collecting duct cells and in Xenopus laevis oocytes heterologously expressing ENaC. The activation depended on urinary serine protease activity. We identified plasmin as a urinary serine protease by matrix-assisted laser desorption/ionization time of-flight mass spectrometry. Purified plasmin activated ENaC currents, and inhibitors of plasmin abolished urinary protease activity and the ability to activate ENaC. In nephrotic syndrome, tubular urokinase-type plasminogen activator likely converts filtered plasminogen to plasmin. Consistent with this, the combined application of urokinase-type plasminogen activator and plasminogen stimulated amiloride-sensitive transepithelial sodium transport in M-1 cells and increased amiloride-sensitive whole-cell currents in Xenopus laevis oocytes heterologously expressing ENaC. Activation of ENaC by plasmin involved cleavage and release of an inhibitory peptide from the ENaC gamma subunit ectodomain. These data suggest that a defective glomerular filtration barrier allows passage of proteolytic enzymes that have the ability to activate ENaC.
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Affiliation(s)
- Per Svenningsen
- Physiology and Pharmacology, Institute of Medical Biology, University of Southern Denmark, Odense C
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Mølstrøm S, Larsen NH, Simonsen JA, Washington R, Bie P. Normotensive sodium loading in normal man: regulation of renin secretion during beta-receptor blockade. Am J Physiol Regul Integr Comp Physiol 2008; 296:R436-45. [PMID: 19073901 DOI: 10.1152/ajpregu.90754.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Saline administration may change renin-angiotensin-aldosterone system (RAAS) activity and sodium excretion at constant mean arterial pressure (MAP). We hypothesized that such responses are elicited mainly by renal sympathetic nerve activity by beta1-receptors (beta1-RSNA), and tested the hypothesis by studying RAAS and renal excretion during slow saline loading at constant plasma sodium concentration (Na+ loading; 12 micromol Na+.kg(-1).min(-1) for 4 h). Normal subjects were studied on low-sodium intake with and without beta1-adrenergic blockade by metoprolol. Metoprolol per se reduced RAAS activity as expected. Na+ loading decreased plasma renin concentration (PRC) by one-third, plasma ANG II by one-half, and plasma aldosterone by two-thirds (all P < 0.05); surprisingly, these changes were found without, as well as during, acute metoprolol administration. Concomitantly, sodium excretion increased indistinguishably with and without metoprolol (16 +/- 2 to 71 +/- 14 micromol/min; 13 +/- 2 to 55 +/- 13 micromol/min, respectively). Na+ loading did not increase plasma atrial natriuretic peptide, glomerular filtration rate (GFR by 51Cr-EDTA), MAP, or cardiac output (CO by impedance cardiography), but increased central venous pressure (CVP) by approximately 2.0 mmHg (P < 0.05). During Na+ loading, sodium excretion increased with CVP at an average slope of 7 micromol.min(-1).mmHg(-1). Concomitantly, plasma vasopressin decreased by 30-40% (P < 0.05). In conclusion, beta1-adrenoceptor blockade affects neither the acute saline-mediated deactivation of RAAS nor the associated natriuretic response, and the RAAS response to modest saline loading seems independent of changes in MAP, CO, GFR, beta1-mediated effects of norepinephrine, and ANP. Unexpectedly, the results do not allow assessment of the relative importance of RAAS-dependent and -independent regulation of renal sodium excretion. The results are compatible with the notion that at constant arterial pressure, a volume receptor elicited reduction in RSNA via receptors other than beta1-adrenoceptors, decreases renal tubular sodium reabsorption proximal to the macula densa leading to increased NaCl concentration at the macula densa, and subsequent inhibition of renin secretion.
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Affiliation(s)
- Simon Mølstrøm
- Department of Physiology and Pharmacology, Institute of Medical Biology, University of Southern Denmark, 21 Winslowparken, Odense, DK-5000, Denmark
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Graugaard-Jensen C, Hvistendahl GM, Frøkiaer J, Bie P, Djurhuus JC. The influence of high and low levels of estrogen on diurnal urine regulation in young women. BMC Urol 2008; 8:16. [PMID: 19019246 PMCID: PMC2626595 DOI: 10.1186/1471-2490-8-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 11/19/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sex hormones have a pronounced effect on arginine vasopressin (AVP), and therefore on the diurnal water homeostasis. Low and high levels of plasma-estradiol as seen in the follicular phase of the menstrual cycle may therefore alter the diurnal regulation of urine production. Furthermore the structural resemblance of oxytocin to vasopressin has led to speculations about the possible antidiuretic properties of oxytocin under normal physiological conditions. To elucidate the influence of high and low p-estradiol on the regulation of the diurnal urine production, 15 normal menstruating women (21-33 y) underwent two circadian in-patient investigations, both situated in follicular phase. METHODS Admitting the participants solely in the follicular phase resulted in high and low plasma-estradiol whereas plasma-progesterone was similar. Urine and blood samples were taken at predetermined time points to determine plasma AVP, plasma oxytocin, plasma aldosterone, plasma natriuretic peptide (ANP), urinary solute excretions, and urinary excretions of prostaglandin E2 (PGE-2) and aquaporin-2 (AQP-2). Blood pressure was measured every hour. RESULTS Plasma AVP, plasma aldosterone and plasma ANP were unaffected by the different levels of estradiol. All had marked circadian variations whereas oxytocin did not display any circadian rhythm. High estradiol resulted in lower p-osmolality and p-sodium reflecting the downward resetting of the osmoreceptors. Oxytocin did not correlate with either diuresis or urine osmolality. The diurnal urine production was similar in the two groups as were urine osmolality, excretion of PGE-2 and AQP-2. AQP-2 does not have a circadian rhythm and is not significantly correlated to either AVP or oxytocin under normal physiological conditions. CONCLUSION High and low level of estradiol has no influence on the circadian rhythm of AVP or the subsequent urine production. High p-estradiol resets the osmoreceptors for AVP release. Furthermore it appears that oxytocin under normal physiological conditions do not contribute to the overall antidiuretic effect.
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Faerch M, Christensen JH, Corydon TJ, Kamperis K, de Zegher F, Gregersen N, Robertson GL, Rittig S. Partial nephrogenic diabetes insipidus caused by a novel mutation in the AVPR2 gene. Clin Endocrinol (Oxf) 2008; 68:395-403. [PMID: 17941907 DOI: 10.1111/j.1365-2265.2007.03054.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To identify the molecular basis and clinical characteristics of X-linked congenital nephrogenic diabetes insipidus (CNDI) presenting with an unusual phenotype characterized by partial resistance to AVP. SUBJECTS The proband was admitted at the age of 4 years with a history of polydipsia and polyuria since infancy. Initial clinical testing confirmed a diagnosis of diabetes insipidus (DI). Urine osmolarity rose during fluid deprivation and after 20 microg of intranasal desmopressin [1-deamino-8-D-arginine-vasopressin (dDAVP)]. A similar DI phenotype was found in his brother. METHODS The coding regions of the AVP gene and the AVP receptor 2 (AVPR2) genes were sequenced in two affected and three unaffected family members. Clinical studies included a fluid deprivation test, intranasal dDAVP challenge, infusion of graded doses of dDAVP and AVP, and measurements of 24-h urine output before and at the end of a 7-day therapeutic trial of intranasal dDAVP. RESULTS A novel missense mutation (1454C > A) in exon 3 of the AVPR2 gene predicting a Ser329Arg substitution was identified in the X-chromosome of the two affected brothers and in one of the X-chromosomes in the mother. The AVPR2 gene was normal in two unaffected siblings. Under basal conditions, the 24-h urine volumes of the two affected boys were 5.5 l (229 ml/kg) and 3.5 l (192 ml/kg), the urine osmolalities were 78 and 90 mosm/kg, and plasma AVP 13.5 and 19.0 pg/ml. Urine osmolalities increased to 573 and 720 mosm/kg while plasma AVP levels were practically unchanged, 13.6 and 8.8 pg/ml, during fluid deprivation. Infusion of AVP resulted in urine osmolalities of 523 and 623 mosm/kg at plasma AVP levels of 58 and 42 pg/ml. Infusion of dDAVP had a similar effect, while treatment with standard doses of intranasal dDAVP had no effect on urine output. DISCUSSION The affected members of this Belgian kindred have CNDI with partial resistance to AVP caused by a mutation in the AVPR2 gene that differs from any of the six mutations reported previously to produce this phenotype. Because the resistance to AVP is partial, this form of CNDI can be difficult to distinguish by indirect diagnostic tests from partial pituitary and dipsogenic DI.
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Affiliation(s)
- Mia Faerch
- Department of Pediatrics, Aarhus University Hospital, Skejby, Aarhus, Denmark
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Kjolby M, Bie P. Chronic activation of plasma renin is log-linearly related to dietary sodium and eliminates natriuresis in response to a pulse change in total body sodium. Am J Physiol Regul Integr Comp Physiol 2008; 294:R17-25. [DOI: 10.1152/ajpregu.00435.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Responses to acute sodium loading depend on the load and on the level of chronic sodium intake. To test the hypothesis that an acute step increase in total body sodium (TBS) elicits a natriuretic response, which is dependent on the chronic level of TBS, we measured the effects of a bolus of NaCl during different low-sodium diets spanning a 25-fold change in sodium intake on elements of the renin-angiotensin-aldosterone system (RAAS) and on natriuresis. To custom-made, low-sodium chow (0.003%), NaCl was added to provide four levels of intake, 0.03–0.75 mmol·kg−1·day−1for 7 days. Acute NaCl administration increased PV (+6.3–8.9%) and plasma sodium concentration (∼2%) and decreased plasma protein concentration (−6.4–8.1%). Plasma ANG II and aldosterone concentrations decreased transiently. Potassium excretion increased substantially. Sodium excretion, arterial blood pressure, glomerular filtration rate, urine flow, plasma potassium, and plasma renin activity did not change. The results indicate that sodium excretion is controlled by neurohumoral mechanisms that are quite resistant to acute changes in plasma volume and colloid osmotic pressure and are not down-regulated within 2 h. With previous data, we demonstrate that RAAS variables are log-linearly related to sodium intake over a >250-fold range in sodium intake, defining dietary sodium function lines that are simple measures of the sodium sensitivity of the RAAS. The dietary function line for plasma ANG II concentration increases from theoretical zero at a daily sodium intake of 17 mmol Na/kg (intercept) with a slope of 16 pM increase per decade of decrease in dietary sodium intake.
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Holte K, Foss NB, Andersen J, Valentiner L, Lund C, Bie P, Kehlet H. Liberal or restrictive fluid administration in fast-track colonic surgery: a randomized, double-blind study. Br J Anaesth 2007; 99:500-8. [PMID: 17681972 DOI: 10.1093/bja/aem211] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Evidence-based guidelines on optimal perioperative fluid management have not been established, and recent randomized trials in major abdominal surgery suggest that large amounts of fluid may increase morbidity and hospital stay. However, no information is available on detailed functional outcomes or with fast-track surgery. Therefore, we investigated the effects of two regimens of intraoperative fluids with physiological recovery as the primary outcome measure after fast-track colonic surgery. METHODS In a double-blind study, 32 ASA I-III patients undergoing elective colonic surgery were randomized to 'restrictive' (Group 1) or 'liberal' (Group 2) perioperative fluid administration. Fluid algorithms were based on fixed rates of crystalloid infusions and a standardized volume of colloid. Pulmonary function (spirometry) was the primary outcome measure, with secondary outcomes of exercise capacity (submaximal exercise test), orthostatic tolerance, cardiovascular hormonal responses, postoperative ileus (transit of radio-opaque markers), postoperative nocturnal hypoxaemia, and overall recovery within a well-defined multimodal, fast-track recovery programme. Hospital stay and complications were also noted. RESULTS 'Restrictive' (median 1640 ml, range 935-2250 ml) compared with 'liberal' fluid administration (median 5050 ml, range 3563-8050 ml) led to significant improvement in pulmonary function and postoperative hypoxaemia. In contrast, we found significantly reduced concentrations of cardiovascularly active hormones (renin, aldosterone, and angiotensin II) in Group 2. The number of patients with complications was not significantly different between the groups [1 ('liberal' group) [corrected] vs 6 ('restrictive' group) [corrected] patients, P = 0.08]. CONCLUSIONS A 'restrictive' [corrected] fluid regimen led to a transient improvement in pulmonary function and postoperative hypoxaemia but no other differences in all-over physiological recovery compared with a 'liberal' [corrected] fluid regimen after fast-track colonic surgery. Since morbidity tended to be increased with the 'restrictive' fluid regimen, future studies should focus on the effect of individualized 'goal-directed' fluid administration strategies rather than fixed fluid amounts on postoperative outcome.
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Affiliation(s)
- K Holte
- Department of Surgical Gastroenterology, Hvidovre University Hospital, DK-2650 Hvidovre, Denmark.
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