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Yin J, Wang Y, Jiang H, Wu C, Sang Z, Sun W, Wei J, Wang W, Liu D, Huang H. Blood urea nitrogen and clinical prognosis in patients with COVID-19: A retrospective study. Medicine (Baltimore) 2024; 103:e37299. [PMID: 38394490 PMCID: PMC10883624 DOI: 10.1097/md.0000000000037299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
The aim of this study was to estimate the association between blood urea nitrogen (BUN) and clinical prognosis in patients with COVID-19. A multicenter, retrospective study was conducted in adult patients with COVID-19 in 3 hospitals in Zhenjiang from January 2023 to May 2023. Patients were divided into survival and death group based on whether they survived at day 28. The demographic, comorbidities, and laboratory data were independently collected and analyzed, as well as clinical outcomes. Total 141 patients were enrolled and 23 (16.3%) died within 28 days. Patients who died within 28 days had a higher level of BUN compared with survivors. Bivariate logistic regression analysis showed that BUN was a risk factor for 28-day mortality in patients with COVID-19. ROC curve showed that BUN could predict 28-day mortality of COVID-19 patients (AUC = 0.796, 95%CI: 0.654-0.938, P < .001). When the cutoff value of BUN was 7.37 mmol/L, the sensitivity and specificity were 84.62% and 70.31%. Subgroup analysis demonstrated that hyper-BUN (≥7.37 mmol/L) was associated with increased 28-day mortality among COVID-19 patients. Patients with COVID-19 who died within 28 days had a higher level of BUN, and hyper-BUN (≥7.37 mmol/L) was associated with increased 28-day mortality.
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Affiliation(s)
- Jiangtao Yin
- Department of Critical Care Medicine, Digestive Disease Institute of Jiangsu University, Affiliated Hospital of Jiangsu University, Zhenjiang, People’s Republic of China
| | - Yuchao Wang
- Medical School of Jiangsu University, Zhenjiang, People’s Republic of China
| | - Hongyan Jiang
- Department of Cardiology, Danyang People’s Hospital, Zhenjiang, People’s Republic of China
| | - Caixia Wu
- Medical School of Jiangsu University, Zhenjiang, People’s Republic of China
| | - Ziyi Sang
- Medical School of Jiangsu University, Zhenjiang, People’s Republic of China
| | - Wen Sun
- Department of Critical Care Medicine, Jurong Hospital Affiliated to Jiangsu University, Zhenjiang, People’s Republic of China
| | - Junfei Wei
- Department of Critical Care Medicine, Traditional Chinese Medicine Hospital of Zhenjiang, Zhenjiang, People’s Republic of China
| | - Wenli Wang
- Department of Critical Care Medicine, Digestive Disease Institute of Jiangsu University, Affiliated Hospital of Jiangsu University, Zhenjiang, People’s Republic of China
| | - Dadong Liu
- Department of Critical Care Medicine, Digestive Disease Institute of Jiangsu University, Affiliated Hospital of Jiangsu University, Zhenjiang, People’s Republic of China
- Department of Critical Care Medicine, Jinling Hospital, Medical School of Nanjing Medical University, Nanjing, People’s Republic of China
| | - Hanpeng Huang
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jiangsu University, Zhenjiang, People’s Republic of China
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Petrovic D, Bankir L, Ponte B, Pruijm M, Corre T, Ghobril JP, Bouatou Y, Ackermann D, Vogt B, Bochud M. The urine-to-plasma urea concentration ratio is associated with eGFR and eGFR decline over time in a population cohort. Nephrol Dial Transplant 2023; 39:122-132. [PMID: 37381173 PMCID: PMC10730796 DOI: 10.1093/ndt/gfad131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND Evaluation of renal function and of factors associated with its decline are important public health issues. Besides markers of glomerular function [e.g. glomerular filtration rate (GFR)], those of tubular functions are rarely evaluated. Urea, the most abundant urinary solute, is markedly concentrated in urine when compared with plasma. We explored the urine-to-plasma ratio of urea concentrations (U/P urea ratio) as a marker of tubular functions. METHODS We evaluated the relationship of the U/P urea ratio with eGFR at baseline in 1043 participants (48 ± 17 years) from the Swiss Kidney Project on Genes in Hypertension (SKIPOGH) population-based cohort, using mixed regression. In 898 participants, we assessed the relation between U/P urea ratio and renal function decline between two study waves 3 years apart. We studied U/P ratios for osmolarity, Na, K and uric acid for comparison. RESULTS In a transversal study at baseline, estimated GFR (eGFR) was positively associated with U/P-urea ratio [βscaled = 0.08, 95% CI (0.04; 0.13)] but not with the U/P ratio of osmolarity. Considering separately participants with renal function >90 or ≤90 mL/min × 1.73 m2, this association was observed only in those with reduced renal function. In the longitudinal study, eGFR declined at a mean rate of 1.2 mL/min per year. A significant association was observed between baseline U/P urea ratio and eGFR decline [βscaled = 0.08, 95% CI (0.01; 0.15)]. A lower baseline U/P urea ratio was associated with a greater eGFR decline. CONCLUSION This study provides evidence that the U/P urea ratio is an early marker of kidney function decline in the general adult population. Urea is easy to measure with well-standardized techniques and at low cost. Thus, the U/P urea ratio could become an easily available tubular marker for evaluating renal function decline.
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Affiliation(s)
- Dusan Petrovic
- Department of Epidemiology and Health Systems (DESS), University Center for General Medicine and Public Health (UNISANTE), Lausanne, Switzerland
- Centre for Environment and Health, School of Public Health, Department of Epidemiology and Biostatistics, Imperial College London, London, UK
| | - Lise Bankir
- Centre de Recherche des Cordeliers, Inserm, Sorbonne Université, Université de Paris, Paris, France
- CNRS, ERL 8228 – Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Belén Ponte
- Department of Nephrology and Hypertension, Geneva University Hospitals, Geneva, Switzerland
| | - Menno Pruijm
- Department of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Tanguy Corre
- Department of Epidemiology and Health Systems (DESS), University Center for General Medicine and Public Health (UNISANTE), Lausanne, Switzerland
| | - Jean-Pierre Ghobril
- Department of Epidemiology and Health Systems (DESS), University Center for General Medicine and Public Health (UNISANTE), Lausanne, Switzerland
| | - Yassine Bouatou
- Department of Nephrology and Hypertension, Geneva University Hospitals, Geneva, Switzerland
| | - Daniel Ackermann
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Bruno Vogt
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Murielle Bochud
- Department of Epidemiology and Health Systems (DESS), University Center for General Medicine and Public Health (UNISANTE), Lausanne, Switzerland
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Gilles N. Natural Peptide Toxins as an Option for Renewed Treatment of Type 2 Vasopressin Receptor-Related Diseases. BIOLOGY 2023; 12:biology12040544. [PMID: 37106745 PMCID: PMC10136000 DOI: 10.3390/biology12040544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/31/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023]
Abstract
The type 2 vasopressin receptor (V2R) is expressed in the kidneys, and it is the keystone of water homeostasis. Under the control of the antidiuretic hormone vasopressin, the V2R ensures vital functions, and any disturbance has dramatic consequences. Despite decades of research to develop drugs capable of activating or blocking V2R function to meet real medical needs, only one agonist and one antagonist are virtually used today. These two drugs cover only a small portion of patients’ needs, leaving millions of patients without treatment. Natural peptide toxins known to act selectively and at low doses on their receptor target could offer new therapeutic options.
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Affiliation(s)
- Nicolas Gilles
- CEA, SIMoS, Département Médicaments et Technologies pour la Santé (DMTS), Université Paris-Saclay, 91191 Gif-sur-Yvette, France
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4
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Kang Y, Wang C, Niu X, Shi Z, Li M, Tian J. Relationship between BUN/Cr and Prognosis of HF Across the Full Spectrum of Ejection Fraction. Arq Bras Cardiol 2023; 120:e20220427. [PMID: 37018789 PMCID: PMC10392858 DOI: 10.36660/abc.20220427] [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: 06/28/2022] [Revised: 10/16/2022] [Accepted: 12/14/2022] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND In patients with heart failure (HF), due to the relative deficiency of blood volume, neurohormone system activation leads to renal vasoconstriction, which affects the content of blood urea nitrogen (BUN) and creatinine (Cr) in the body, while BUN and Cr are easily affected by other factors. Therefore, BUN/Cr can be used as another marker for the prognosis of HF. OBJECTIVE Explore the prognosis of adverse outcome of HF in the high BUN/Cr group compared with the low BUN/Cr group across the full spectrum of ejection fraction. METHODS From 2014 to 2016, symptomatic hospitalized HF patients were recruited and followed up to observe adverse cardiovascular outcomes. Logistic analysis and COX analysis were performed to determine significance. p-values <0.05 were considered statistically significant. RESULTS In the univariate logistic regression analysis, the high BUN/Cr group had a higher risk of adverse outcome in heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). Multivariate logistic regression analysis showed that the risk of cardiac death in the HFrEF group was higher than that in the low BUN/Cr group, while the risk of all-cause death was significant only in 3 months (p<0.05) (Central Illustration). The risk of all-cause death in the high BUN/Cr in the HFpEF group was significantly higher than that in the low BUN/Cr group at two years. CONCLUSION The high BUN/Cr group is related to the risk of poor prognosis of HFpEF, and is not lower than the predictive value of left ventricular ejection fraction (LVEF).
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Affiliation(s)
- Yuan Kang
- Department of GeriatricsTianjin Medical UniversityGeneral HospitalTianjinChinaDepartment of Geriatrics, Tianjin Medical University General Hospital, Tianjin – China
| | - Conglin Wang
- Department of GeriatricsTianjin Medical UniversityGeneral HospitalTianjinChinaDepartment of Geriatrics, Tianjin Medical University General Hospital, Tianjin – China
| | - Xiaojing Niu
- Department of GeriatricsTianjin Medical UniversityGeneral HospitalTianjinChinaDepartment of Geriatrics, Tianjin Medical University General Hospital, Tianjin – China
| | - Zhijing Shi
- Department of GeriatricsTianjin Medical UniversityGeneral HospitalTianjinChinaDepartment of Geriatrics, Tianjin Medical University General Hospital, Tianjin – China
| | - Mingxue Li
- Department of GeriatricsTianjin Medical UniversityGeneral HospitalTianjinChinaDepartment of Geriatrics, Tianjin Medical University General Hospital, Tianjin – China
| | - Jianli Tian
- Department of GeriatricsTianjin Medical UniversityGeneral HospitalTianjinChinaDepartment of Geriatrics, Tianjin Medical University General Hospital, Tianjin – China
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Nash MT, Quijada-Rodriguez AR, Allen GJP, Wilson JM, Weihrauch D. Characterization of 3 different types of aquaporins in Carcinus maenas and their potential role in osmoregulation. Comp Biochem Physiol A Mol Integr Physiol 2022; 272:111281. [PMID: 35902004 DOI: 10.1016/j.cbpa.2022.111281] [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: 06/08/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 11/18/2022]
Abstract
Intertidal crustaceans like Carcinus maenas shift between an osmoconforming and osmoregulating state when inhabiting full-strength seawater and dilute environments, respectively. While the bodily fluids and environment of marine osmoconformers are approximately isosmotic, osmoregulating crabs inhabiting dilute environments maintain their bodily fluid osmolality above that of their environment by actively absorbing and retaining osmolytes (e.g., Na+, Cl-, urea) while eliminating excess water. Few studies have investigated the role of aquaporins (AQPs) in the osmoregulatory organs of crustaceans, especially within brachyuran species. In the current study, three different aquaporins were identified within a transcriptome of C. maenas, including a classical AQP (CmAQP1), an aquaglyceroporin (CmGLP1), and a big-brain protein (CmBIB1), all of which are expressed in the gills and the antennal glands. Functional expression of these aquaporins confirmed water transport capabilities for CmAQP1, CmGLP1, but not for CmBIB1, while CmGLP1 also transported urea. Higher relative CmAQP1 mRNA expression within tissues of osmoconforming crabs suggests the apical/sub-apically localized channel attenuates osmotic gradients created by non-osmoregulatory processes while its downregulation in dilute media reduces the water permeability of tissues to facilitate osmoregulation. Although hemolymph urea concentrations rose upon exposure to brackish water, urea was not detected in the final urine. Due to its urea-transport capabilities, CmGLP1 is hypothesized to be involved in a urea retention mechanism believed to be involved in the production of diluted urine. Overall, these results suggest that AQPs are involved in osmoregulation and provide a basis for future mechanistic studies investigating the role of AQPs in volume regulation in crustaceans.
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Affiliation(s)
- M T Nash
- Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | | | - G J P Allen
- Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - J M Wilson
- Biology, Wilfrid Laurier University, Waterloo, Canada
| | - D Weihrauch
- Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
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Hus-Citharel A, Bouby N, Corbani M, Mion J, Mendre C, Darusi J, Tomboly C, Trueba M, Serradeil-Le Gal C, Llorens-Cortes C, Guillon G. Characterization of a functional V 1B vasopressin receptor in the male rat kidney: evidence for cross talk between V 1B and V 2 receptor signaling pathways. Am J Physiol Renal Physiol 2021; 321:F305-F321. [PMID: 34282956 DOI: 10.1152/ajprenal.00081.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although vasopressin V1B receptor (V1BR) mRNA has been detected in the kidney, the precise renal localization as well as pharmacological and physiological properties of this receptor remain unknown. Using the selective V1B agonist d[Leu4, Lys8]VP, either fluorescent or radioactive, we showed that V1BR is mainly present in principal cells of the inner medullary collecting duct (IMCD) in the male rat kidney. Protein and mRNA expression of V1BR were very low compared with the V2 receptor (V2R). On the microdissected IMCD, d[Leu4, Lys8]VP had no effect on cAMP production but induced a dose-dependent and saturable intracellular Ca2+ concentration increase mobilization with an EC50 value in the nanomolar range. This effect involved both intracellular Ca2+ mobilization and extracellular Ca2+ influx. The selective V1B antagonist SSR149415 strongly reduced the ability of vasopressin to increase intracellular Ca2+ concentration but also cAMP, suggesting a cooperation between V1BR and V2R in IMCD cells expressing both receptors. This cooperation arises from a cross talk between second messenger cascade involving PKC rather than receptor heterodimerization, as supported by potentiation of arginine vasopressin-stimulated cAMP production in human embryonic kidney-293 cells coexpressing the two receptor isoforms and negative results obtained by bioluminescence resonance energy transfer experiments. In vivo, only acute administration of high doses of V1B agonist triggered significant diuretic effects, in contrast with injection of selective V2 agonist. This study brings new data on the localization and signaling pathways of V1BR in the kidney, highlights a cross talk between V1BR and V2R in the IMCD, and suggests that V1BR may counterbalance in some pathophysiological conditions the antidiuretic effect triggered by V2R activation.NEW & NOTEWORTHY Although V1BR mRNA has been detected in the kidney, the precise renal localization as well as pharmacological and physiological properties of this receptor remain unknown. Using original pharmaceutical tools, this study brings new data on the localization and signaling pathways of V1BR, highlights a cross talk between V1BR and V2 receptor (V2R) in the inner medullary collecting duct, and suggests that V1BR may counterbalance in some pathophysiological conditions the antidiuretic effect triggered by V2R activation.
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Affiliation(s)
- Annette Hus-Citharel
- Collège de France, Neuropeptides Centraux et Régulations Hydrique et Cardiovasculaire, Centre Interdisciplinaire de Recherche en Biologie, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Paris, France
| | - Nadine Bouby
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France
| | - Maithé Corbani
- Institut de Génomique Fonctionnelle, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, France
| | - Julie Mion
- Institut de Génomique Fonctionnelle, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, France
| | - Christiane Mendre
- Institut de Génomique Fonctionnelle, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, France
| | - Judit Darusi
- Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Csaba Tomboly
- Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Miguel Trueba
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, Basque Country University, Leioa, Spain
| | | | - Catherine Llorens-Cortes
- Collège de France, Neuropeptides Centraux et Régulations Hydrique et Cardiovasculaire, Centre Interdisciplinaire de Recherche en Biologie, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Paris, France
| | - Gilles Guillon
- Institut de Génomique Fonctionnelle, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, France
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Heida JE, Gansevoort RT, Messchendorp AL, Meijer E, Casteleijn NF, Boertien WE, Zittema D. Use of the Urine-to-Plasma Urea Ratio to Predict ADPKD Progression. Clin J Am Soc Nephrol 2021; 16:204-212. [PMID: 33504546 PMCID: PMC7863649 DOI: 10.2215/cjn.10470620] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 12/09/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND OBJECTIVES Predicting disease progression in patients with autosomal dominant polycystic kidney disease (ADPKD) poses a challenge, especially in early-stage disease when kidney function is not yet affected. Ongoing growth of cysts causes maximal urine-concentrating capacity to decrease from early on. We therefore hypothesized that the urine-to-plasma urea ratio, as a reflection of the urine-concentrating capacity, can be used as a marker to predict ADPKD progression. DESIGN The urine-to-plasma urea ratio was calculated by dividing concentrations of early morning fasting spot urine urea by plasma urea. First, this ratio was validated as surrogate marker in 30 patients with ADPKD who underwent a prolonged water deprivation test. Thereafter, association with kidney outcome was evaluated in 583 patients with ADPKD with a broad range of kidney function. Multivariable mixed-model regression was used to assess association with eGFR slope, and logarithmic regression to identify patients with rapidly progressive disease, using a cutoff of -3.0 ml/min per 1.73 m2 per year. The urine-to-plasma urea ratio was compared with established predictors, namely, sex, age, baseline eGFR, Mayo Clinic height-adjusted total kidney volume class, and PKD gene mutation. RESULTS The maximal urine-concentrating capacity and urine-to-plasma urea ratio correlated strongly (R=0.90; P<0.001). Next, the urine-to-plasma urea ratio was significantly associated with rate of eGFR decline during a median follow-up of 4.0 (interquartile range, 2.6-5.0) years, both crude and after correction for established predictors (β=0.58; P=0.02). The odds ratio of rapidly progressive disease was 1.35 (95% confidence interval, 1.19 to 1.52; P<0.001) for every 10 units decrease in urine-to-plasma urea ratio, with adjustment for predictors. A combined risk score of the urine-to-plasma urea ratio, Mayo Clinic height-adjusted total kidney volume class, and PKD mutation predicted rapidly progressive disease better than each of the predictors separately. CONCLUSIONS The urine-to-plasma urea ratio, which is calculated from routine laboratory measurements, predicts disease progression in ADPKD in addition to other risk markers. PODCAST This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_01_27_CJN10470620_final.mp3.
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Affiliation(s)
- Judith E. Heida
- Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ron T. Gansevoort
- Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A. Lianne Messchendorp
- Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Esther Meijer
- Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Niek F. Casteleijn
- Department of Urology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Wendy E. Boertien
- Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Debbie Zittema
- Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Zhang S, Zhao Y, Wang S, Li M, Xu Y, Ran J, Geng X, He J, Meng J, Shao G, Zhou H, Ge Z, Chen G, Li R, Yang B. Discovery of novel diarylamides as orally active diuretics targeting urea transporters. Acta Pharm Sin B 2021; 11:181-202. [PMID: 33532188 PMCID: PMC7838058 DOI: 10.1016/j.apsb.2020.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/14/2020] [Accepted: 05/26/2020] [Indexed: 12/17/2022] Open
Abstract
Urea transporters (UT) play a vital role in the mechanism of urine concentration and are recognized as novel targets for the development of salt-sparing diuretics. Thus, UT inhibitors are promising for development as novel diuretics. In the present study, a novel UT inhibitor with a diarylamide scaffold was discovered by high-throughput screening. Optimization of the inhibitor led to the identification of a promising preclinical candidate, N-[4-(acetylamino)phenyl]-5-nitrofuran-2-carboxamide (1H), with excellent in vitro UT inhibitory activity at the submicromolar level. The half maximal inhibitory concentrations of 1H against UT-B in mouse, rat, and human erythrocyte were 1.60, 0.64, and 0.13 μmol/L, respectively. Further investigation suggested that 8 μmol/L 1H more powerfully inhibited UT-A1 at a rate of 86.8% than UT-B at a rate of 73.9% in MDCK cell models. Most interestingly, we found for the first time that oral administration of 1H at a dose of 100 mg/kg showed superior diuretic effect in vivo without causing electrolyte imbalance in rats. Additionally, 1H did not exhibit apparent toxicity in vivo and in vitro, and possessed favorable pharmacokinetic characteristics. 1H shows promise as a novel diuretic to treat hyponatremia accompanied with volume expansion and may cause few side effects.
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Key Words
- AQP1, aquaporin 1
- BCRP, breast cancer resistance protein
- CCK-8, cell counting kit-8
- CMC-Na, carboxymethylcellulose sodium
- DMF, N,N-dimethylformamide
- Diuretic
- Fa, fraction absorbance
- GFR, glomerular filtration rate
- HDL-C and LDL-C, high- and low-density lipoprotein
- IC50, half maximal inhibitory concentration
- IMCD, inner medulla collecting duct
- Oral administration
- P-gp, P-glycoprotein
- PBS, phosphate buffered saline
- Papp, apparent permeability
- Structure optimization
- THF, tetrahydrofuran
- UT, urea transporter
- Urea transporter inhibitor
- r.t., room temperature
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Nam GH, Mishra A, Gim JA, Lee HE, Jo A, Yoon D, Kim A, Kim WJ, Ahn K, Kim DH, Kim S, Cha HJ, Choi YH, Park CI, Kim HS. Gene expression profiles alteration after infection of virus, bacteria, and parasite in the Olive flounder (Paralichthys olivaceus). Sci Rep 2018; 8:18065. [PMID: 30584247 PMCID: PMC6305387 DOI: 10.1038/s41598-018-36342-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 11/14/2018] [Indexed: 01/25/2023] Open
Abstract
Olive flounder (Paralichthys olivaceus) is one of economically valuable fish species in the East Asia. In comparison with its economic importance, available genomic information of the olive flounder is very limited. The mass mortality caused by variety of pathogens (virus, bacteria and parasites) is main problem in aquaculture industry, including in olive flounder culture. In this study, we carried out transcriptome analysis using the olive flounder gill tissues after infection of three types of pathogens (Virus; Viral hemorrhagic septicemia virus, Bacteria; Streptococcus parauberis, and Parasite; Miamiensis avidus), respectively. As a result, we identified total 12,415 differentially expressed genes (DEG) from viral infection, 1,754 from bacterial infection, and 795 from parasite infection, respectively. To investigate the effects of pathogenic infection on immune response, we analyzed Gene ontology (GO) enrichment analysis with DEGs and sorted immune-related GO terms per three pathogen groups. Especially, we verified various GO terms, and genes in these terms showed down-regulated expression pattern. In addition, we identified 67 common genes (10 up-regulated and 57 down-regulated) present in three pathogen infection groups. Our goals are to provide plenty of genomic knowledge about olive flounder transcripts for further research and report genes, which were changed in their expression after specific pathogen infection.
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Affiliation(s)
- Gyu-Hwi Nam
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Anshuman Mishra
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Jeong-An Gim
- Center for Convergence Approaches in Drug Development (CCADD), Graduate School of Convergence Science and Technology, Seoul National University, Suwon, 16229, Republic of Korea
| | - Hee-Eun Lee
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Ara Jo
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Dahye Yoon
- Department of Chemistry, Center for Proteome Biophysics and Chemistry Institute for Functional Materials, Pusan National University, Busan, 46241, Republic of Korea
| | - Ahran Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, Republic of Korea
| | - Woo-Jin Kim
- Biotechnology Research Division, National Fisheries Research and Development Institute, 216 Gijanghaean-ro, Gijang-eup, Gijang-gun, Busan, 46083, Republic of Korea
| | - Kung Ahn
- Theragen ETEX Bio Institute, Suwon, 16229, Republic of Korea
| | - Do-Hyung Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, Republic of Korea
| | - Suhkmann Kim
- Department of Chemistry, Center for Proteome Biophysics and Chemistry Institute for Functional Materials, Pusan National University, Busan, 46241, Republic of Korea
| | - Hee-Jae Cha
- Department of Parasitology and Genetics, Kosin University College of Medicine, Busan, 49267, Korea
| | - Yung Hyun Choi
- Department of Biochemistry, College of Oriental Medicine, Dongeui University, Busan, 47227, Korea
| | - Chan-Il Park
- Department of Marine Biology and Aquaculture, College of Marine Science, Gyeongsang National University, Tongyeong, 53064, Korea
| | - Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea.
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea.
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10
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Channavajjhala SK, Bramley R, Peltz T, Oosthuyzen W, Jia W, Kinnear S, Sampson B, Martin N, Hall IP, Bailey MA, Dear JW, Glover M. Urinary Extracellular Vesicle Protein Profiling and Endogenous Lithium Clearance Support Excessive Renal Sodium Wasting and Water Reabsorption in Thiazide-Induced Hyponatremia. Kidney Int Rep 2018; 4:139-147. [PMID: 30596177 PMCID: PMC6308385 DOI: 10.1016/j.ekir.2018.09.011] [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: 06/06/2018] [Revised: 08/22/2018] [Accepted: 09/17/2018] [Indexed: 12/11/2022] Open
Abstract
Introduction Thiazide diuretics are among the most widely used antihypertensive medications worldwide. Thiazide-induced hyponatremia (TIH) is 1 of their most clinically significant adverse effects. A priori TIH must result from excessive saliuresis and/or water reabsorption. We hypothesized that pathways regulating the thiazide-sensitive sodium-chloride cotransporter NCC and the water channel aquaporin-2 (AQP2) may be involved. Our aim was to assess whether patients with TIH would show evidence of altered NCC and AQP2 expression in urinary extracellular vesicles (UEVs), and also whether abnormalities of renal sodium reabsorption would be evident using endogenous lithium clearance (ELC). Methods Blood and urine samples were donated by patients admitted to hospital with acute symptomatic TIH, after recovery to normonatremia, and also from normonatremic controls on and off thiazides. Urinary extracellular vesicles were isolated and target proteins evaluated by western blotting and by nanoparticle tracking analysis. Endogenous lithium clearance was assessed by inductively coupled plasma mass spectrometry. Results Analysis of UEVs by western blotting showed that patients with acute TIH displayed reduced total NCC and increased phospho-NCC and AQP2 relative to appropriate control groups; smaller differences in NCC and AQP2 expression persisted after recovery from TIH. These findings were confirmed by nanoparticle tracking analysis. Renal ELC was lower in acute TIH compared to that in controls and convalescent case patients. Conclusion Reduced NCC expression and increased AQP2 expression would be expected to result in saliuresis and water reabsorption in TIH patients. This study raises the possibility that UEV analysis may be of diagnostic utility in less clear-cut cases of thiazide-associated hyponatremia, and may help to identify patients at risk for TIH before thiazide initiation.
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Affiliation(s)
- Sarath K Channavajjhala
- Division of Therapeutics and Molecular Medicine, University of Nottingham, Nottingham, UK.,NIHR-Nottingham Biomedical Research Centre, Nottinghamshire, UK
| | - Roger Bramley
- Trace Element Laboratory, Imperial College Healthcare NHS Trust, Charing Cross Hospital, London, UK
| | - Theresa Peltz
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Wilna Oosthuyzen
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Wenjing Jia
- Division of Therapeutics and Molecular Medicine, University of Nottingham, Nottingham, UK.,NIHR-Nottingham Biomedical Research Centre, Nottinghamshire, UK
| | - Sue Kinnear
- Division of Therapeutics and Molecular Medicine, University of Nottingham, Nottingham, UK.,NIHR-Nottingham Biomedical Research Centre, Nottinghamshire, UK
| | - Barry Sampson
- Trace Element Laboratory, Imperial College Healthcare NHS Trust, Charing Cross Hospital, London, UK
| | - Nick Martin
- Trace Element Laboratory, Imperial College Healthcare NHS Trust, Charing Cross Hospital, London, UK
| | - Ian P Hall
- Division of Therapeutics and Molecular Medicine, University of Nottingham, Nottingham, UK.,NIHR-Nottingham Biomedical Research Centre, Nottinghamshire, UK
| | - Matthew A Bailey
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - James W Dear
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Mark Glover
- Division of Therapeutics and Molecular Medicine, University of Nottingham, Nottingham, UK.,NIHR-Nottingham Biomedical Research Centre, Nottinghamshire, UK
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11
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PGE 2 EP 1 receptor inhibits vasopressin-dependent water reabsorption and sodium transport in mouse collecting duct. J Transl Med 2018; 98:360-370. [PMID: 29251736 DOI: 10.1038/labinvest.2017.133] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/12/2017] [Accepted: 09/25/2017] [Indexed: 01/14/2023] Open
Abstract
PGE2 regulates glomerular hemodynamics, renin secretion, and tubular transport. This study examined the contribution of PGE2 EP1 receptors to sodium and water homeostasis. Male EP1-/- mice were bred with hypertensive TTRhRen mice (Htn) to evaluate blood pressure and kidney function at 8 weeks of age in four groups: wildtype (WT), EP1-/-, Htn, HtnEP1-/-. Blood pressure and water balance were unaffected by EP1 deletion. COX1 and mPGE2 synthase were increased and COX2 was decreased in mice lacking EP1, with increases in EP3 and reductions in EP2 and EP4 mRNA throughout the nephron. Microdissected proximal tubule sglt1, NHE3, and AQP1 were increased in HtnEP1-/-, but sglt2 was increased in EP1-/- mice. Thick ascending limb NKCC2 was reduced in the cortex but increased in the medulla. Inner medullary collecting duct (IMCD) AQP1 and ENaC were increased, but AVP V2 receptors and urea transporter-1 were reduced in all mice compared to WT. In WT and Htn mice, PGE2 inhibited AVP-water transport and increased calcium in the IMCD, and inhibited sodium transport in cortical collecting ducts, but not in EP1-/- or HtnEP1-/- mice. Amiloride (ENaC) and hydrochlorothiazide (pendrin inhibitor) equally attenuated the effect of PGE2 on sodium transport. Taken together, the data suggest that EP1 regulates renal aquaporins and sodium transporters, attenuates AVP-water transport and inhibits sodium transport in the mouse collecting duct, which is mediated by both ENaC and pendrin-dependent pathways.
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12
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Abstract
Vasopressin (AVP) plays a major role in the regulation of water and sodium homeostasis by its antidiuretic action on the kidney, mediated by V2 receptors. AVP secretion is stimulated by a rise in plasma osmolality, a decline in blood volume or stress. V1a receptors are expressed in vascular smooth muscle cells, but the role of vasopressin in blood pressure regulation is still a matter of debate. AVP may also play a role in some metabolic pathways, including gluconeogenesis, through its action on V1a receptors expressed in the liver. It is now understood that thirst and arginine vasopressin (AVP) release are regulated not only by the classical homeostatic, intero-sensory plasma osmolality negative feedback, but also by novel, extero-sensory, anticipatory signals. AVP measurement is time-consuming, and AVP level in the blood in the physiological range is often below the detection limit of the assays. Recently, an immunoassay has been developed for the measurement of copeptin, a fragment of the pre-provasopressin molecule that is easier to measure. It has been shown to be a good surrogate marker of AVP.
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Affiliation(s)
- L Bankir
- Centre de Recherche des Cordeliers, INSERM Unit 1138, 75006, Paris, France.,Université Pierre et Marie Curie, 75006, Paris, France
| | - D G Bichet
- Université de Montréal, Montréal, QC, Canada.,Départements de Pharmacologie, Physiologie et de Médecine, Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada
| | - N G Morgenthaler
- Institut für Experimentelle Endokrinologie, Charité Universitätsmedizin Berlin, Berlin, Germany.,InVivo Biotech Services, Neuendorfstraße 24a, Hennigsdorf/Berlin, Germany
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13
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Influence of renal dysfunction phenotype on mortality in decompensated heart failure with preserved and mid-range ejection fraction. Int J Cardiol 2017; 243:332-339. [DOI: 10.1016/j.ijcard.2017.05.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 05/10/2017] [Indexed: 01/17/2023]
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14
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Vinod P, Krishnappa V, Chauvin AM, Khare A, Raina R. Cardiorenal Syndrome: Role of Arginine Vasopressin and Vaptans in Heart Failure. Cardiol Res 2017; 8:87-95. [PMID: 28725324 PMCID: PMC5505291 DOI: 10.14740/cr553w] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 05/18/2017] [Indexed: 02/06/2023] Open
Abstract
Heart and kidney failure continued to be of increasing prevalence in today's society, and their comorbidity has synergistic effect on the morbidity and mortality of patients. Cardiorenal syndrome (CRS) is a complex disease with multifactorial pathophysiology. Better understanding of this pathophysiological network is crucial for the successful intervention to prevent advancement of the disease process. One of the major factors in this process is neurohormonal activation, predominantly involving renin-angiotensin-aldosterone system (RAAS) and arginine vasopressin (AVP). Heart failure causes reduced cardiac output/cardiac index (CO/CI) and fall in renal perfusion pressures resulting in activation of baroreceptors and RAAS, respectively. Activated baroreceptors and RAAS stimulate the release of AVP (non-osmotic pathway), which acts on V2 receptors located in the renal collecting ducts, causing fluid retention and deterioration of heart failure. Effective blockade of AVP action on V2 receptors has emerged as a potential treatment option in volume overload conditions especially in the setting of hyponatremia. Vasopressin receptor antagonists (VRAs), such as vaptans, are potent aquaretics causing electrolyte-free water diuresis without significant electrolyte abnormalities. Vaptans are useful in hypervolemic hyponatremic conditions like heart failure and liver cirrhosis, and euvolemic hyponatremic conditions like syndrome of inappropriate anti-diuretic hormone secretion. Tolvaptan and conivaptan are pharmaceutical agents that are available for the treatment of these conditions.
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Affiliation(s)
- Poornima Vinod
- Department of Internal Medicine, Cleveland Clinic Akron General, Akron, OH, USA
| | - Vinod Krishnappa
- Cleveland Clinic Akron General/Akron Nephrology Associates, Akron, OH, USA
| | | | - Anshika Khare
- Northeast Ohio Medical University, Rootstown, OH, USA
| | - Rupesh Raina
- Department of Nephrology, Cleveland Clinic Akron General, Akron, OH, USA
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15
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Jujo K, Minami Y, Haruki S, Matsue Y, Shimazaki K, Kadowaki H, Ishida I, Kambayashi K, Arashi H, Sekiguchi H, Hagiwara N. Persistent high blood urea nitrogen level is associated with increased risk of cardiovascular events in patients with acute heart failure. ESC Heart Fail 2017; 4:545-553. [PMID: 29154415 PMCID: PMC5695177 DOI: 10.1002/ehf2.12188] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 12/04/2022] Open
Abstract
Aims The association between kinetics of blood urea nitrogen (BUN) levels in hospital and cardiovascular outcomes in patients with acutely decompensated congestive heart failure (HF) is unclear. We aimed to estimate the impact of changes in BUN level during hospitalization on clinical prognosis in patients with acute HF. Methods and results A total of 353 consecutive patients that were urgently hospitalized due to acutely decompensated HF and discharged alive were divided into four subgroups depending on their BUN level at admission and discharge, using a cut‐off level of 21.0 mg/dL. Among 206 patients with high baseline BUN level, 46 (22%) and 160 (78%) had normal and persistent high BUN levels at discharge, respectively. In contrast, of the 147 patients with normal baseline BUN level, 55 (37%) and 92 (63%) had high and normal BUN levels at discharge, respectively. During the observational period after discharge, Kaplan–Meier analysis showed the highest rate of combined outcome of cardiovascular death and HF readmission in patients with persistent high BUN (log‐rank test: P < 0.001). After adjustment for comorbidities, the hazard ratio for a combined outcome was significantly lower in patients with normalized BUN level compared with those with persistent high BUN (hazard ratio 0.48, 95% confidence interval 0.23–0.99, P = 0.049). Conclusions Persistent high BUN levels in hospital are associated with an increased risk of cardiovascular death and HF readmission. Normalization of BUN levels during hospitalization may be associated with long‐term clinical outcomes.
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Affiliation(s)
- Kentaro Jujo
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Yuichiro Minami
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Shintaro Haruki
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Yuya Matsue
- Department of Cardiology, Kameda Medical Center, Kamogawa, Japan
| | - Kensuke Shimazaki
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Hiromu Kadowaki
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Issei Ishida
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Keigo Kambayashi
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Hiroyuki Arashi
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Haruki Sekiguchi
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Nobuhisa Hagiwara
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
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16
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Yin WJ, Yi YH, Guan XF, Zhou LY, Wang JL, Li DY, Zuo XC. Preprocedural Prediction Model for Contrast-Induced Nephropathy Patients. J Am Heart Assoc 2017; 6:JAHA.116.004498. [PMID: 28159819 PMCID: PMC5523753 DOI: 10.1161/jaha.116.004498] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Several models have been developed for prediction of contrast‐induced nephropathy (CIN); however, they only contain patients receiving intra‐arterial contrast media for coronary angiographic procedures, which represent a small proportion of all contrast procedures. In addition, most of them evaluate radiological interventional procedure‐related variables. So it is necessary for us to develop a model for prediction of CIN before radiological procedures among patients administered contrast media. Methods and Results A total of 8800 patients undergoing contrast administration were randomly assigned in a 4:1 ratio to development and validation data sets. CIN was defined as an increase of 25% and/or 0.5 mg/dL in serum creatinine within 72 hours above the baseline value. Preprocedural clinical variables were used to develop the prediction model from the training data set by the machine learning method of random forest, and 5‐fold cross‐validation was used to evaluate the prediction accuracies of the model. Finally we tested this model in the validation data set. The incidence of CIN was 13.38%. We built a prediction model with 13 preprocedural variables selected from 83 variables. The model obtained an area under the receiver‐operating characteristic (ROC) curve (AUC) of 0.907 and gave prediction accuracy of 80.8%, sensitivity of 82.7%, specificity of 78.8%, and Matthews correlation coefficient of 61.5%. For the first time, 3 new factors are included in the model: the decreased sodium concentration, the INR value, and the preprocedural glucose level. Conclusions The newly established model shows excellent predictive ability of CIN development and thereby provides preventative measures for CIN.
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Affiliation(s)
- Wen-Jun Yin
- Clinical Pharmacy and Pharmacology Research Institute, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yi-Hu Yi
- Xiangya School of Medical Science of Central South University, Changsha, Hunan, China
| | - Xiao-Feng Guan
- Clinical Pharmacy and Pharmacology Research Institute, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Ling-Yun Zhou
- Clinical Pharmacy and Pharmacology Research Institute, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jiang-Lin Wang
- Clinical Pharmacy and Pharmacology Research Institute, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Dai-Yang Li
- Clinical Pharmacy and Pharmacology Research Institute, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Xiao-Cong Zuo
- Clinical Pharmacy and Pharmacology Research Institute, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
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17
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Hassouneh R, Nasrallah R, Zimpelmann J, Gutsol A, Eckert D, Ghossein J, Burns KD, Hébert RL. PGE2 receptor EP3 inhibits water reabsorption and contributes to polyuria and kidney injury in a streptozotocin-induced mouse model of diabetes. Diabetologia 2016; 59:1318-28. [PMID: 26995650 DOI: 10.1007/s00125-016-3916-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/19/2016] [Indexed: 10/22/2022]
Abstract
AIMS/HYPOTHESIS The first clinical manifestation of diabetes is polyuria. The prostaglandin E2 (PGE2) receptor EP3 antagonises arginine vasopressin (AVP)-mediated water reabsorption and its expression is increased in the diabetic kidney. The purpose of this work was to study the contribution of EP3 to diabetic polyuria and renal injury. METHODS Male Ep 3 (-/-) (also known as Ptger3 (-/-)) mice were treated with streptozotocin (STZ) to generate a mouse model of diabetes and renal function was evaluated after 12 weeks. Isolated collecting ducts (CDs) were microperfused to study the contribution of EP3 to AVP-mediated fluid reabsorption. RESULTS Ep 3 (-/-)-STZ mice exhibited attenuated polyuria and increased urine osmolality compared with wild-type STZ (WT-STZ) mice, suggesting enhanced water reabsorption. Compared with WT-STZ mice, Ep 3 (-/-)-STZ mice also had increased protein expression of aquaporin-1, aquaporin-2, and urea transporter A1, and reduced urinary AVP excretion, but increased medullary V2 receptors. In vitro microperfusion studies indicated that Ep 3 (-/-) and WT-STZ CDs responded to AVP stimulation similarly to those of wild-type mice, with a 60% increase in fluid reabsorption. In WT non-injected and WT-STZ mice, EP3 activation with sulprostone (PGE2 analogue) abrogated AVP-mediated water reabsorption; this effect was absent in mice lacking EP3. A major finding of this work is that Ep 3 (-/-)-STZ mice showed blunted renal cyclooxygenase-2 protein expression, reduced renal hypertrophy, reduced hyperfiltration and reduced albuminuria, as well as diminished tubular dilation and nuclear cysts. CONCLUSIONS/INTERPRETATION Taken together, the data suggest that EP3 contributes to diabetic polyuria by inhibiting expression of aquaporins and that it promotes renal injury during diabetes. EP3 may prove to be a promising target for more selective management of diabetic kidney disease.
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Affiliation(s)
- Ramzi Hassouneh
- Department of Cellular and Molecular Medicine, Kidney Research Centre, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada, K1H 8M5
| | - Rania Nasrallah
- Department of Cellular and Molecular Medicine, Kidney Research Centre, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada, K1H 8M5
| | - Joe Zimpelmann
- Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Alex Gutsol
- Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - David Eckert
- Department of Cellular and Molecular Medicine, Kidney Research Centre, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada, K1H 8M5
| | - Jamie Ghossein
- Department of Cellular and Molecular Medicine, Kidney Research Centre, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada, K1H 8M5
| | - Kevin D Burns
- Department of Cellular and Molecular Medicine, Kidney Research Centre, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada, K1H 8M5
- Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Richard L Hébert
- Department of Cellular and Molecular Medicine, Kidney Research Centre, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada, K1H 8M5.
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18
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Effect of Glycyrrhiza on the Diuretic Function of Euphorbia kansui: An Ascites Mouse Model. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:7620817. [PMID: 27247609 PMCID: PMC4876214 DOI: 10.1155/2016/7620817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/25/2016] [Accepted: 04/06/2016] [Indexed: 12/23/2022]
Abstract
We investigated the therapeutic role of the herbal combination Euphorbia kansui (GS) and Glycyrrhiza (GC) in ascites during hepatocellular carcinoma (HCC). The AVPR2 and AQP2 expression in kidney tissues of ascites mice in different groups was determined by immunohistochemistry, Western blot, and real-time PCR analyses. When the dose of GS was less than 0.70 g/kg at a ratio of GC : GS not exceeding 0.4 : 1, the combination of GS and GC exhibited synergistic effects on HCC ascites and significantly elevated the expression levels of AVPR2 and AQP2 (all P < 0.05). On the contrary, when GS ≥ 0.93 g/kg and GC ≥ 1.03 g/kg with the GC-to-GS ratio exceeding 1.11 : 1, the combination of GS and GC displayed antagonistic effects on HCC ascites and dramatically reduced the expression levels of AVPR2 and AQP2 (all P < 0.05). Furthermore, the administration of herbal pair GS and GC at different ratios did not exacerbate the pathological changes in liver and kidney tissues of HCC ascites mice. The different combinations of GS and GC exerted synergistic or antagonistic effects on HCC ascites, partially by regulating the expression of AVPR2 and AQP2.
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19
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Jujo K, Saito K, Ishida I, Furuki Y, Kim A, Suzuki Y, Sekiguchi H, Yamaguchi J, Ogawa H, Hagiwara N. Randomized pilot trial comparing tolvaptan with furosemide on renal and neurohumoral effects in acute heart failure. ESC Heart Fail 2016; 3:177-188. [PMID: 27818782 PMCID: PMC5071712 DOI: 10.1002/ehf2.12088] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 02/07/2016] [Accepted: 02/09/2016] [Indexed: 01/11/2023] Open
Abstract
AIMS Loop diuretics are first-line medications for congestive heart failure (CHF); however, they are associated with serious adverse effects, including decreased renal function, and sympathetic nervous and renin-angiotensin system activation. We tested whether tolvaptan, a vasopressin V2-receptor antagonist, could reduce unfavourable furosemide-induced effects during CHF treatment. METHODS AND RESULTS Sixty patients emergently hospitalized owing to CHF-induced dyspnea were randomly assigned to receive either 40 mg intravenous furosemide daily or 7.5 mg oral tolvaptan for 5 days after admission. Both groups also received intravenous carperitide and canrenoate potassium. As results, baseline patient characteristics were similar between the furosemide (n = 30) and the tolvaptan (n = 30) groups, with no significant difference in 5 day urine volume or fluid balance. Brain natriuretic peptide and body weight improvements were similar between groups. However, serum creatinine (Cr) level did not increase, and the incidence of worsening renal function was significantly lower in the tolvaptan group. Consequently, the Cr increase to gain 1000 mL urine was 2.5-fold lower in the tolvaptan group. Furthermore, the blood urea nitrogen (BUN)/Cr ratio significantly decreased in the tolvaptan group, suggesting that renal perfusion was preserved, and urea reuptake and passive water reabsorption were suppressed following tolvaptan treatment. Although catecholamine improvements after treatment were not significantly different, plasma renin activity was enhanced in the furosemide group. CONCLUSIONS As compared with furosemide, tolvaptan in patients with acute heart failure is associated with comparable decongestion, better preservation of renal function and less activation of renin-angiotensin system. (UMIN 000014134).
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Affiliation(s)
- Kentaro Jujo
- Department of CardiologyTokyo Women's Medical UniversityTokyoJapan; Department of CardiologyNishiarai Heart Center HospitalTokyoJapan
| | - Katsumi Saito
- Department of Cardiology Nishiarai Heart Center Hospital Tokyo Japan
| | - Issei Ishida
- Department of Cardiology Nishiarai Heart Center Hospital Tokyo Japan
| | - Yuho Furuki
- Department of Cardiology Nishiarai Heart Center Hospital Tokyo Japan
| | - Ahsung Kim
- Department of Cardiology Nishiarai Heart Center Hospital Tokyo Japan
| | - Yuki Suzuki
- Department of Cardiology Nishiarai Heart Center Hospital Tokyo Japan
| | - Haruki Sekiguchi
- Department of Cardiology, Aoyama Hospital Tokyo Women's Medical University Tokyo Japan
| | - Junichi Yamaguchi
- Department of Cardiology Tokyo Women's Medical University Tokyo Japan
| | - Hiroshi Ogawa
- Department of Cardiology Tokyo Women's Medical University Tokyo Japan
| | - Nobuhisa Hagiwara
- Department of Cardiology Tokyo Women's Medical University Tokyo Japan
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20
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Kortenoeven MLA, Pedersen NB, Rosenbaek LL, Fenton RA. Vasopressin regulation of sodium transport in the distal nephron and collecting duct. Am J Physiol Renal Physiol 2015; 309:F280-99. [DOI: 10.1152/ajprenal.00093.2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/27/2015] [Indexed: 12/22/2022] Open
Abstract
Arginine vasopressin (AVP) is released from the posterior pituitary gland during states of hyperosmolality or hypovolemia. AVP is a peptide hormone, with antidiuretic and antinatriuretic properties. It allows the kidneys to increase body water retention predominantly by increasing the cell surface expression of aquaporin water channels in the collecting duct alongside increasing the osmotic driving forces for water reabsorption. The antinatriuretic effects of AVP are mediated by the regulation of sodium transport throughout the distal nephron, from the thick ascending limb through to the collecting duct, which in turn partially facilitates osmotic movement of water. In this review, we will discuss the regulatory role of AVP in sodium transport and summarize the effects of AVP on various molecular targets, including the sodium-potassium-chloride cotransporter NKCC2, the thiazide-sensitive sodium-chloride cotransporter NCC, and the epithelial sodium channel ENaC.
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Affiliation(s)
- M. L. A. Kortenoeven
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
| | - N. B. Pedersen
- Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; and
| | - L. L. Rosenbaek
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - R. A. Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
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21
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Cil O, Esteva-Font C, Tas ST, Su T, Lee S, Anderson MO, Ertunc M, Verkman AS. Salt-sparing diuretic action of a water-soluble urea analog inhibitor of urea transporters UT-A and UT-B in rats. Kidney Int 2015; 88:311-20. [PMID: 25993324 PMCID: PMC4523423 DOI: 10.1038/ki.2015.138] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 03/10/2015] [Accepted: 03/26/2015] [Indexed: 11/09/2022]
Abstract
Inhibitors of kidney urea transporter (UT) proteins have potential use as salt-sparing diuretics ('urearetics') with a different mechanism of action than diuretics that target salt transporters. To study UT inhibition in rats, we screened about 10,000 drugs, natural products and urea analogs for inhibition of rat UT-A1. Drug and natural product screening found nicotine, sanguinarine and an indolcarbonylchromenone with IC50 of 10-20 μM. Urea analog screening found methylacetamide and dimethylthiourea (DMTU). DMTU fully and reversibly inhibited rat UT-A1 and UT-B by a noncompetitive mechanism with IC50 of 2-3 mM. Homology modeling and docking computations suggested DMTU binding sites on rat UT-A1. Following a single intraperitoneal injection of 500 mg/kg DMTU, peak plasma concentration was 9 mM with t1/2 of about 10 h, and a urine concentration of 20-40 mM. Rats chronically treated with DMTU had a sustained, reversible reduction in urine osmolality from 1800 to 600 mOsm, a 3-fold increase in urine output, and mild hypokalemia. DMTU did not impair urinary concentrating function in rats on a low protein diet. Compared to furosemide-treated rats, the DMTU-treated rats had greater diuresis and reduced urinary salt loss. In a model of syndrome of inappropriate antidiuretic hormone secretion, DMTU treatment prevented hyponatremia and water retention produced by water-loading in dDAVP-treated rats. Thus, our results establish a rat model of UT inhibition and demonstrate the diuretic efficacy of UT inhibition.
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Affiliation(s)
- Onur Cil
- 1] Departments of Medicine and Physiology, University of California, San Francisco, CA, USA [2] Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Cristina Esteva-Font
- Departments of Medicine and Physiology, University of California, San Francisco, CA, USA
| | - Sadik Taskin Tas
- Department of Pharmacology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Tao Su
- Departments of Medicine and Physiology, University of California, San Francisco, CA, USA
| | - Sujin Lee
- Departments of Medicine and Physiology, University of California, San Francisco, CA, USA
| | - Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA, USA
| | - Mert Ertunc
- Department of Pharmacology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California, San Francisco, CA, USA
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Esteva-Font C, Phuan PW, Lee S, Su T, Anderson MO, Verkman AS. Structure-activity analysis of thiourea analogs as inhibitors of UT-A and UT-B urea transporters. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1848:1075-80. [PMID: 25613743 PMCID: PMC4364388 DOI: 10.1016/j.bbamem.2015.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/10/2014] [Accepted: 01/09/2015] [Indexed: 10/24/2022]
Abstract
Small-molecule inhibitors of urea transporter (UT) proteins in kidney have potential application as novel salt-sparing diuretics. The urea analog dimethylthiourea (DMTU) was recently found to inhibit the UT isoforms UT-A1 (expressed in kidney tubule epithelium) and UT-B (expressed in kidney vasa recta endothelium) with IC50 of 2-3 mM, and was shown to have diuretic action when administered to rats. Here, we measured UT-A1 and UT-B inhibition activity of 36 thiourea analogs, with the goal of identifying more potent and isoform-selective inhibitors, and establishing structure-activity relationships. The analog set systematically explored modifications of substituents on the thiourea including alkyl, heterocycles and phenyl rings, with different steric and electronic features. The analogs had a wide range of inhibition activities and selectivities. The most potent inhibitor, 3-nitrophenyl-thiourea, had an IC50 of ~0.2 mM for inhibition of both UT-A1 and UT-B. Some analogs such as 4-nitrophenyl-thiourea were relatively UT-A1 selective (IC50 1.3 vs. 10 mM), and others such as thioisonicotinamide were UT-B selective (IC50>15 vs. 2.8 mM).
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Affiliation(s)
- Cristina Esteva-Font
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Puay-Wah Phuan
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Sujin Lee
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Tao Su
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132-4136, USA
| | - A S Verkman
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA.
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AVP-induced increase in AQP2 and p-AQP2 is blunted in heart failure during cardiac remodeling and is associated with decreased AT1R abundance in rat kidney. PLoS One 2015; 10:e0116501. [PMID: 25658446 PMCID: PMC4319737 DOI: 10.1371/journal.pone.0116501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 12/10/2014] [Indexed: 01/02/2023] Open
Abstract
AIM The objective was to examine the renal effects of long-term increased angiotensin II and vasopressin plasma levels in early-stage heart failure (HF). We investigated the regulations of the V2 vasopressin receptor, the type 1A angiotensin II receptor, the (pro)renin receptor, and the water channels AQP2, AQP1, AQP3, and AQP4 in the inner medulla of rat kidney. METHODS HF was induced by coronary artery ligation. Sixty-eight rats were allocated to six groups: Sham (N = 11), HF (N = 11), sodium restricted sham (N = 11), sodium restricted HF (N = 11), sodium restricted sham + DDAVP (N = 12), and sodium restricted HF + DDAVP (N = 12). 1-desamino-8-D-arginine vasopressin (0.5 ng h-1 for 7 days) or vehicle was administered. Pre- and post-treatment echocardiographic evaluation was performed. The rats were sacrificed at day 17 after surgery, before cardiac remodeling in rat is known to be completed. RESULTS HF rats on standard sodium diet and sodium restriction displayed biochemical markers of HF. These rats developed hyponatremia, hypo-osmolality, and decreased fractional excretion of sodium. Increase of AQP2 and p(Ser256)-AQP2 abundance in all HF groups was blunted compared with control groups even when infused with DDAVP and despite increased vasopressin V2 receptor and Gsα abundance. This was associated with decreased protein abundance of the AT1A receptor in HF groups vs. controls. CONCLUSION Early-stage HF is associated with blunted increase in AQP2 and p(Ser256)-AQP2 despite of hyponatremia, hypo-osmolality, and increased inner medullary vasopressin V2 receptor expression. Decreased type 1A angiotensin II receptor abundance likely plays a role in the transduction of these effects.
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Esteva-Font C, Anderson MO, Verkman AS. Urea transporter proteins as targets for small-molecule diuretics. Nat Rev Nephrol 2015; 11:113-23. [PMID: 25488859 PMCID: PMC4743986 DOI: 10.1038/nrneph.2014.219] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Conventional diuretics such as furosemide and thiazides target salt transporters in kidney tubules, but urea transporters (UTs) have emerged as alternative targets. UTs are a family of transmembrane channels expressed in a variety of mammalian tissues, in particular the kidney. UT knockout mice and humans with UT mutations exhibit reduced maximal urinary osmolality, demonstrating that UTs are necessary for the concentration of urine. Small-molecule screening has identified potent and selective inhibitors of UT-A, the UT protein expressed in renal tubule epithelial cells, and UT-B, the UT protein expressed in vasa recta endothelial cells. Data from UT knockout mice and from rodents administered UT inhibitors support the diuretic action of UT inhibition. The kidney-specific expression of UT-A1, together with high selectivity of the small-molecule inhibitors, means that off-target effects of such small-molecule drugs should be minimal. This Review summarizes the structure, expression and function of UTs, and looks at the evidence supporting the validity of UTs as targets for the development of salt-sparing diuretics with a unique mechanism of action. UT-targeted inhibitors may be useful alone or in combination with conventional diuretics for therapy of various oedemas and hyponatraemias, potentially including those refractory to treatment with current diuretics.
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Affiliation(s)
- Cristina Esteva-Font
- Departments of Medicine and Physiology, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA
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Abstract
Renal dysfunction (RD) in heart failure portends adverse outcomes and often limits aggressive medical and decongestive therapies. Despite the high prevalence in this population, not all forms of RD are prognostically or mechanistically equivalent: RD can result from irreversible nephron loss secondary to diabetic or hypertensive kidney disease or it can develop secondary to heart failure (HF) itself, i.e., the cardiorenal syndrome. Furthermore, filtration is only one aspect of renal performance such that significant renal impairment secondary to cardiorenal syndrome can exist despite a normal glomerular filtration rate. Renal biomarkers have the potential to inform some of the intricacies involved in accurately assessing cardiorenal interactions. This article discusses novel biomarkers for cardiorenal syndrome and their utility in the prognosis, diagnosis, and targeted treatment of heart failure-induced RD.
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Affiliation(s)
- Meredith A Brisco
- Division of Cardiology, Advanced Heart Failure and Cardiac Transplantation, Medical University of South Carolina, 25 Courtenay Drive, ART 7061, MSC 592, Charleston, SC, 29425-5920, USA,
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Esteva-Font C, Cil O, Phuan PW, Su T, Lee S, Anderson MO, Verkman AS. Diuresis and reduced urinary osmolality in rats produced by small-molecule UT-A-selective urea transport inhibitors. FASEB J 2014; 28:3878-90. [PMID: 24843071 PMCID: PMC4139901 DOI: 10.1096/fj.14-253872] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/05/2014] [Indexed: 11/11/2022]
Abstract
Urea transport (UT) proteins of the UT-A class are expressed in epithelial cells in kidney tubules, where they are required for the formation of a concentrated urine by countercurrent multiplication. Here, using a recently developed high-throughput assay to identify UT-A inhibitors, a screen of 50,000 synthetic small molecules identified UT-A inhibitors of aryl-thiazole, γ-sultambenzosulfonamide, aminocarbonitrile butene, and 4-isoxazolamide chemical classes. Structure-activity analysis identified compounds that inhibited UT-A selectively by a noncompetitive mechanism with IC50 down to ∼1 μM. Molecular modeling identified putative inhibitor binding sites on rat UT-A. To test compound efficacy in rats, formulations and administration procedures were established to give therapeutic inhibitor concentrations in blood and urine. We found that intravenous administration of an indole thiazole or a γ-sultambenzosulfonamide at 20 mg/kg increased urine output by 3-5-fold and reduced urine osmolality by ∼2-fold compared to vehicle control rats, even under conditions of maximum antidiuresis produced by 1-deamino-8-D-arginine vasopressin (DDAVP). The diuresis was reversible and showed urea > salt excretion. The results provide proof of concept for the diuretic action of UT-A-selective inhibitors. UT-A inhibitors are first in their class salt-sparing diuretics with potential clinical indications in volume-overload edemas and high-vasopressin-associated hyponatremias.
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Affiliation(s)
- Cristina Esteva-Font
- Department of Medicine and Department of Physiology, University of California, San Francisco, California, USA and
| | - Onur Cil
- Department of Medicine and Department of Physiology, University of California, San Francisco, California, USA and
| | - Puay-Wah Phuan
- Department of Medicine and Department of Physiology, University of California, San Francisco, California, USA and
| | - Tao Su
- Department of Medicine and Department of Physiology, University of California, San Francisco, California, USA and
| | - Sujin Lee
- Department of Medicine and Department of Physiology, University of California, San Francisco, California, USA and
| | - Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California, USA
| | - A S Verkman
- Department of Medicine and Department of Physiology, University of California, San Francisco, California, USA and
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Jönsson S, Agic MB, Narfström F, Melville JM, Hultström M. Renal neurohormonal regulation in heart failure decompensation. Am J Physiol Regul Integr Comp Physiol 2014; 307:R493-7. [PMID: 24920735 DOI: 10.1152/ajpregu.00178.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Decompensation in heart failure occurs when the heart fails to balance venous return with cardiac output, leading to fluid congestion and contributing to mortality. Decompensated heart failure can cause acute kidney injury (AKI), which further increases mortality. Heart failure activates signaling systems that are deleterious to kidneys such as renal sympathetic nerve activity (RSNA), renin-angiotensin-aldosterone system, and vasopressin secretion. All three reduce renal blood flow (RBF) and increase tubular sodium reabsorption, which may increase renal oxygen consumption causing AKI through renal tissue hypoxia. Vasopressin contributes to venous congestion through aquaporin-mediated water retention. Additional water retention may be mediated through vasopressin-induced medullary urea transport and hyaluronan but needs further study. In addition, there are several systems that could protect the kidneys and reduce fluid retention such as natriuretic peptides, prostaglandins, and nitric oxide. However, the effect of natriuretic peptides and nitric oxide are blunted in decompensation, partly due to oxidative stress. This review considers how neurohormonal signaling in heart failure drives fluid retention by the kidneys and thus exacerbates decompensation. It further identifies areas where there is limited data, such as signaling systems 20-HETE, purines, endothelin, the role of renal water retention mechanisms for congestion, and renal hypoxia in AKI during heart failure.
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Affiliation(s)
- Sofia Jönsson
- Unit for Integrative Physiology, Department of Medical Cellbiology, Uppsala University, Uppsala, Sweden; and
| | - Mediha Becirovic Agic
- Unit for Integrative Physiology, Department of Medical Cellbiology, Uppsala University, Uppsala, Sweden; and
| | - Fredrik Narfström
- Unit for Anaesthesiology and Intensive Care, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Jacqueline M Melville
- Unit for Integrative Physiology, Department of Medical Cellbiology, Uppsala University, Uppsala, Sweden; and
| | - Michael Hultström
- Unit for Integrative Physiology, Department of Medical Cellbiology, Uppsala University, Uppsala, Sweden; and Unit for Anaesthesiology and Intensive Care, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
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28
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Verkman AS, Esteva-Font C, Cil O, Anderson MO, Li F, Li M, Lei T, Ren H, Yang B. Small-molecule inhibitors of urea transporters. Subcell Biochem 2014; 73:165-77. [PMID: 25298345 PMCID: PMC4306426 DOI: 10.1007/978-94-017-9343-8_11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Urea transporter (UT) proteins, which include isoforms of UT-A in kidney tubule epithelia and UT-B in vasa recta endothelia and erythrocytes, facilitate urinary concentrating function. Inhibitors of urea transporter function have potential clinical applications as sodium-sparing diuretics, or 'urearetics,' in edema from different etiologies, such as congestive heart failure and cirrhosis, as well as in syndrome of inappropriate antidiuretic hormone (SIADH). High-throughput screening of drug-like small molecules has identified UT-A and UT-B inhibitors with nanomolar potency. Inhibitors have been identified with different UT-A versus UT-B selectivity profiles and putative binding sites on UT proteins. Studies in rodent models support the utility of UT inhibitors in reducing urinary concentration, though testing in clinically relevant animal models of edema has not yet been done.
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Affiliation(s)
- Alan S Verkman
- Departments of Medicine and Physiology, University of California, San Francisco, CA, 94143-0521, USA,
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29
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Leroy C, Karrouz W, Douillard C, Do Cao C, Cortet C, Wémeau JL, Vantyghem MC. Diabetes insipidus. ANNALES D'ENDOCRINOLOGIE 2013; 74:496-507. [DOI: 10.1016/j.ando.2013.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 09/23/2013] [Accepted: 10/07/2013] [Indexed: 01/13/2023]
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Esteva-Font C, Phuan PW, Anderson MO, Verkman AS. A small molecule screen identifies selective inhibitors of urea transporter UT-A. CHEMISTRY & BIOLOGY 2013; 20:1235-44. [PMID: 24055006 PMCID: PMC3890325 DOI: 10.1016/j.chembiol.2013.08.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 08/05/2013] [Accepted: 08/15/2013] [Indexed: 01/24/2023]
Abstract
Urea transporter (UT) proteins, including UT-A in kidney tubule epithelia and UT-B in vasa recta microvessels, facilitate urinary concentrating function. A screen for UT-A inhibitors was developed in MDCK cells expressing UT-A1, water channel aquaporin-1, and YFP-H148Q/V163S. An inwardly directed urea gradient produces cell shrinking followed by UT-A1-dependent swelling, which was monitored by YFP-H148Q/V163S fluorescence. Screening of ~90,000 synthetic small molecules yielded four classes of UT-A1 inhibitors with low micromolar half-maximal inhibitory concentration that fully and reversibly inhibited urea transport by a noncompetitive mechanism. Structure-activity analysis of >400 analogs revealed UT-A1-selective and UT-A1/UT-B nonselective inhibitors. Docking computations based on homology models of UT-A1 suggested inhibitor binding sites. UT-A inhibitors may be useful as diuretics ("urearetics") with a mechanism of action that may be effective in fluid-retaining conditions in which conventional salt transport-blocking diuretics have limited efficacy.
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Affiliation(s)
- Cristina Esteva-Font
- Departments of Medicine and Physiology, University of California, San Francisco, San Francisco, CA 94143-0521, USA
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31
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Moss R, Thomas SR. Hormonal regulation of salt and water excretion: a mathematical model of whole kidney function and pressure natriuresis. Am J Physiol Renal Physiol 2013; 306:F224-48. [PMID: 24107423 DOI: 10.1152/ajprenal.00089.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We present a lumped-nephron model that explicitly represents the main features of the underlying physiology, incorporating the major hormonal regulatory effects on both tubular and vascular function, and that accurately simulates hormonal regulation of renal salt and water excretion. This is the first model to explicitly couple glomerulovascular and medullary dynamics, and it is much more detailed in structure than existing whole organ models and renal portions of multiorgan models. In contrast to previous medullary models, which have only considered the antidiuretic state, our model is able to regulate water and sodium excretion over a variety of experimental conditions in good agreement with data from experimental studies of the rat. Since the properties of the vasculature and epithelia are explicitly represented, they can be altered to simulate pathophysiological conditions and pharmacological interventions. The model serves as an appropriate starting point for simulations of physiological, pathophysiological, and pharmacological renal conditions and for exploring the relationship between the extrarenal environment and renal excretory function in physiological and pathophysiological contexts.
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Affiliation(s)
- Robert Moss
- Mathematics Dept., Duke Univ., Box 90320, Durham, NC 27708-0320.
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32
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Shayakul C, Clémençon B, Hediger MA. The urea transporter family (SLC14): physiological, pathological and structural aspects. Mol Aspects Med 2013; 34:313-22. [PMID: 23506873 DOI: 10.1016/j.mam.2012.12.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 12/12/2012] [Indexed: 11/27/2022]
Abstract
Urea transporters (UTs) belonging to the solute carrier 14 (SLC14) family comprise two genes with a total of eight isoforms in mammals, UT-A1 to -A6 encoded by SLC14A2 and UT-B1 to -B2 encoded by SLC14A1. Recent efforts have been directed toward understanding the molecular and cellular mechanisms involved in the regulation of UTs using transgenic mouse models and heterologous expression systems, leading to important new insights. Urea uptake by UT-A1 and UT-A3 in the kidney inner medullary collecting duct and by UT-B1 in the descending vasa recta for the countercurrent exchange system are chiefly responsible for medullary urea accumulation in the urinary concentration process. Vasopressin, an antidiuretic hormone, regulates UT-A isoforms via the phosphorylation and trafficking of the glycosylated transporters to the plasma membrane that occurs to maintain equilibrium with the exocytosis and ubiquitin-proteasome degradation pathways. UT-B isoforms are also important in several cellular functions, including urea nitrogen salvaging in the colon, nitric oxide pathway modulation in the hippocampus, and the normal cardiac conduction system. In addition, genomic linkage studies have revealed potential additional roles for SLC14A1 and SLC14A2 in hypertension and bladder carcinogenesis. The precise role of UT-A2 and presence of the urea recycling pathway in normal kidney are issues to be further explored. This review provides an update of these advances and their implications for our current understanding of the SLC14 UTs.
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Affiliation(s)
- Chairat Shayakul
- Renal Unit, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
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33
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Moeller HB, Rittig S, Fenton RA. Nephrogenic diabetes insipidus: essential insights into the molecular background and potential therapies for treatment. Endocr Rev 2013; 34:278-301. [PMID: 23360744 PMCID: PMC3610677 DOI: 10.1210/er.2012-1044] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The water channel aquaporin-2 (AQP2), expressed in the kidney collecting ducts, plays a pivotal role in maintaining body water balance. The channel is regulated by the peptide hormone arginine vasopressin (AVP), which exerts its effects through the type 2 vasopressin receptor (AVPR2). Disrupted function or regulation of AQP2 or the AVPR2 results in nephrogenic diabetes insipidus (NDI), a common clinical condition of renal origin characterized by polydipsia and polyuria. Over several years, major research efforts have advanced our understanding of NDI at the genetic, cellular, molecular, and biological levels. NDI is commonly characterized as hereditary (congenital) NDI, arising from genetic mutations in the AVPR2 or AQP2; or acquired NDI, due to for exmple medical treatment or electrolyte disturbances. In this article, we provide a comprehensive overview of the genetic, cell biological, and pathophysiological causes of NDI, with emphasis on the congenital forms and the acquired forms arising from lithium and other drug therapies, acute and chronic renal failure, and disturbed levels of calcium and potassium. Additionally, we provide an overview of the exciting new treatment strategies that have been recently proposed for alleviating the symptoms of some forms of the disease and for bypassing G protein-coupled receptor signaling.
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Affiliation(s)
- Hanne B Moeller
- Department of Biomedicine, Aarhus University, and Department of Pediatrics, Aarhus University Hospital, Wilhelm Meyers Alle 3, Building 1234, Aarhus 8000, Denmark.
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Bankir L, Bouby N, Ritz E. Vasopressin: a novel target for the prevention and retardation of kidney disease? Nat Rev Nephrol 2013; 9:223-39. [PMID: 23438973 DOI: 10.1038/nrneph.2013.22] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
After several decades during which little attention was paid to vasopressin and/or urine concentration in clinical practice, interest in vasopressin has renewed with the availability of new, potent, orally active vasopressin-receptor antagonists--the vaptans--and with the results of epidemiological studies evaluating copeptin (a surrogate marker of vasopressin) in large population-based cohorts. Several experimental studies in rats and mice had previously shown that vasopressin, acting via vasopressin V2 antidiuretic receptors, contributes to the progression of chronic kidney disease; in particular, to autosomal dominant polycystic kidney disease. New epidemiological studies now suggest a role for vasopressin in the pathogenesis of diabetes mellitus and metabolic disorders via activation of hepatic V1a and/or pancreatic islet V1b receptors. The first part of this Review describes the adverse effects of vasopressin, as revealed by clinical and experimental studies in kidney diseases, hypertension, diabetes and the metabolic syndrome. The second part provides insights into vasopressin physiology and pathophysiology that may be relevant to the understanding of these adverse effects and that are linked to the excretion of concentrated nitrogen wastes and associated hyperfiltration. Collectively, the studies reviewed here suggest that more attention should be given to the vasopressin-thirst-urine concentration axis in clinical investigations and in patient care. Whether selective blockade of the different vasopressin receptors may provide therapeutic benefits beyond their present indication in hyponatraemia requires new clinical trials.
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Affiliation(s)
- Lise Bankir
- INSERM UMRS 872, Equipe 2, Centre de Recherche des Cordeliers, Paris, France.
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35
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Brisco MA, Coca SG, Chen J, Owens AT, McCauley BD, Kimmel SE, Testani JM. Blood urea nitrogen/creatinine ratio identifies a high-risk but potentially reversible form of renal dysfunction in patients with decompensated heart failure. Circ Heart Fail 2013; 6:233-9. [PMID: 23325460 DOI: 10.1161/circheartfailure.112.968230] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Identifying reversible renal dysfunction (RD) in the setting of heart failure is challenging. The goal of this study was to evaluate whether elevated admission blood urea nitrogen/creatinine ratio (BUN/Cr) could identify decompensated heart failure patients likely to experience improvement in renal function (IRF) with treatment. METHODS AND RESULTS Consecutive hospitalizations with a discharge diagnosis of heart failure were reviewed. IRF was defined as ≥20% increase and worsening renal function as ≥20% decrease in estimated glomerular filtration rate. IRF occurred in 31% of the 896 patients meeting eligibility criteria. Higher admission BUN/Cr was associated with in-hospital IRF (odds ratio, 1.5 per 10 increase; 95% confidence interval [CI], 1.3-1.8; P<0.001), an association persisting after adjustment for baseline characteristics (odds ratio, 1.4; 95% CI, 1.1-1.8; P=0.004). However, higher admission BUN/Cr was also associated with post-discharge worsening renal function (odds ratio, 1.4; 95% CI, 1.1-1.8; P=0.011). Notably, in patients with an elevated admission BUN/Cr, the risk of death associated with RD (estimated glomerular filtration rate <45) was substantial (hazard ratio, 2.2; 95% CI, 1.6-3.1; P<0.001). However, in patients with a normal admission BUN/Cr, RD was not associated with increased mortality (hazard ratio, 1.2; 95% CI, 0.67-2.0; P=0.59; p interaction=0.03). CONCLUSIONS An elevated admission BUN/Cr identifies decompensated patients with heart failure likely to experience IRF with treatment, providing proof of concept that reversible RD may be a discernible entity. However, this improvement seems to be largely transient, and RD, in the setting of an elevated BUN/Cr, remains strongly associated with death. Further research is warranted to develop strategies for the optimal detection and treatment of these high-risk patients.
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Affiliation(s)
- Meredith A Brisco
- Department of Medicine, Cardiovascular Division, University of Pennsylvania, Philadelphia, PA, USA
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Abstract
Prostanoids are prominent, yet complex, components in the maintenance of body water homeostasis. Recent functional and molecular studies have revealed that the local lipid mediator PGE2 is involved both in water excretion and absorption. The biologic actions of PGE2 are exerted through four different G-protein-coupled receptors; designated EP1-4, which couple to separate intracellular signaling pathways. Here, we discuss new developments in our understanding of the actions of PGE2 that have been uncovered utilizing receptor specific agonists and antagonists, EP receptor and PG synthase knockout mice, polyuric animal models, and the new understanding of the molecular regulation of collecting duct water permeability. The role of PGE2 in urinary concentration comprises a variety of mechanisms, which are not fully understood and likely depend on which receptor is activated under a particular physiologic condition. EP3 and microsomal PG synthase type 1 play a role in decreasing collecting duct water permeability and increasing water excretion, whereas EP2 and EP4 can bypass vasopressin signaling and increase water reabsorption through two different intracellular signaling pathways. PGE2 has an intricate role in urinary concentration, and we now suggest how targeting specific prostanoid receptor signaling pathways could be exploited for the treatment of disorders in water balance.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Su H, Carter CB, Laur O, Sands JM, Chen G. Forskolin stimulation promotes urea transporter UT-A1 ubiquitination, endocytosis, and degradation in MDCK cells. Am J Physiol Renal Physiol 2012; 303:F1325-32. [PMID: 22914781 PMCID: PMC3518190 DOI: 10.1152/ajprenal.00248.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 08/21/2012] [Indexed: 11/22/2022] Open
Abstract
The adenylyl cyclase stimulator forskolin (FSK) stimulates UT-A1 phosphorylation, membrane trafficking, and urea transport activity. Here, we found that FSK stimulation induces UT-A1 ubiquitination in UT-A1 Madin-Darby canine kidney (MDCK) cells. This suggests that phosphorylation by FSK also triggers the protein degradation machinery for UT-A1. UT-A1-MDCK cells were treated with 100 μg/ml cycloheximide to inhibit protein synthesis, with or without 10 μM FSK. Total UT-A1 protein abundance was significantly reduced after FSK treatment, concomitantly ubiquitinated UT-A1 was increased. We then specifically investigated the effect of FSK on UT-A1 expressed on the cell plasma membrane. FSK treatment accelerated UT-A1 removal from the cell plasma membrane by increasing UT-A1 endocytosis as judged by biotinylation/MesNa treatment and confocal microscopy. We further found that inhibition of the clathrin-mediated endocytic pathway, but not the caveolin-mediated endocytic pathway, significantly blocks FSK-stimulated UT-A1 endocytosis. The PKA inhibitor H89 and the proteasome inhibitors MG132 and lactacystin reduced FSK-induced membrane UT-A1 reduction. Our study shows that FSK activates the UT-A1 urea transporter and the activation/phosphorylation subsequently triggers the downregulation of UT-A1, which represents an important mechanism for the cell to return to the basal conditions after vasopressin stimulation.
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Affiliation(s)
- Hua Su
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, GA 30322, USA
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Anderson MO, Zhang J, Liu Y, Yao C, Phuan PW, Verkman AS. Nanomolar potency and metabolically stable inhibitors of kidney urea transporter UT-B. J Med Chem 2012; 55:5942-50. [PMID: 22694147 PMCID: PMC3590912 DOI: 10.1021/jm300491y] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Urea transporters, which include UT-B in kidney microvessels, are potential targets for development of drugs with a novel diuretic ('urearetic') mechanism. We recently identified, by high-throughput screening, a triazolothienopyrimidine UT-B inhibitor, 1, that selectively and reversibly inhibited urea transport with IC(50) = 25.1 nM and reduced urinary concentration in mice ( Yao et al. J. Am. Soc. Nephrol. , in press ). Here, we analyzed 273 commercially available analogues of 1 to establish a structure-activity series and synthesized a targeted library of 11 analogues to identify potent, metabolically stable UT-B inhibitors. The best compound, {3-[4-(1,1-difluoroethyl)benzenesulfonyl]thieno[2,3-e][1,2,3]triazolo[1,5-a]pyrimidin-5-yl}thiophen-2-ylmethylamine, 3k, had IC(50) of 23 and 15 nM for inhibition of urea transport by mouse and human UT-B, respectively, and ∼40-fold improved in vitro metabolic stability compared to 1. In mice, 3k accumulated in kidney and urine and reduced maximum urinary concentration. Triazolothienopyrimidines may be useful for therapy of diuretic-refractory edema in heart and liver failure.
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Affiliation(s)
- Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California 94132-4136, United States.
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Abstract
The central goal of this overview article is to summarize recent findings in renal epithelial transport,focusing chiefly on the connecting tubule (CNT) and the cortical collecting duct (CCD).Mammalian CCD and CNT are involved in fine-tuning of electrolyte and fluid balance through reabsorption and secretion. Specific transporters and channels mediate vectorial movements of water and solutes in these segments. Although only a small percent of the glomerular filtrate reaches the CNT and CCD, these segments are critical for water and electrolyte homeostasis since several hormones, for example, aldosterone and arginine vasopressin, exert their main effects in these nephron sites. Importantly, hormones regulate the function of the entire nephron and kidney by affecting channels and transporters in the CNT and CCD. Knowledge about the physiological and pathophysiological regulation of transport in the CNT and CCD and particular roles of specific channels/transporters has increased tremendously over the last two decades.Recent studies shed new light on several key questions concerning the regulation of renal transport.Precise distribution patterns of transport proteins in the CCD and CNT will be reviewed, and their physiological roles and mechanisms mediating ion transport in these segments will also be covered. Special emphasis will be given to pathophysiological conditions appearing as a result of abnormalities in renal transport in the CNT and CCD.
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Affiliation(s)
- Alexander Staruschenko
- Department of Physiology and Kidney Disease Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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Stewart G. The emerging physiological roles of the SLC14A family of urea transporters. Br J Pharmacol 2012; 164:1780-92. [PMID: 21449978 DOI: 10.1111/j.1476-5381.2011.01377.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In mammals, urea is the main nitrogenous breakdown product of protein catabolism and is produced in the liver. In certain tissues, the movement of urea across cell membranes is specifically mediated by a group of proteins known as the SLC14A family of facilitative urea transporters. These proteins are derived from two distinct genes, UT-A (SLC14A2) and UT-B (SLC14A1). Facilitative urea transporters play an important role in two major physiological processes - urinary concentration and urea nitrogen salvaging. Although UT-A and UT-B transporters both have a similar basic structure and mediate the transport of urea in a facilitative manner, there are a number of significant differences between them. UT-A transporters are mainly found in the kidney, are highly specific for urea, have relatively lower transport rates and are highly regulated at both gene expression and cellular localization levels. In contrast, UT-B transporters are more widespread in their tissue location, transport both urea and water, have a relatively high transport rate, are inhibited by mercurial compounds and currently appear to be less acutely regulated. This review details the fundamental research that has so far been performed to investigate the function and physiological significance of these two types of urea transporters.
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Affiliation(s)
- Gavin Stewart
- School of Biology & Environmental Science, College of Life Sciences, University College Dublin, Belfield, Dublin, Ireland.
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Lei T, Zhou L, Layton AT, Zhou H, Zhao X, Bankir L, Yang B. Role of thin descending limb urea transport in renal urea handling and the urine concentrating mechanism. Am J Physiol Renal Physiol 2011; 301:F1251-9. [PMID: 21849488 PMCID: PMC3233864 DOI: 10.1152/ajprenal.00404.2011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 08/15/2011] [Indexed: 11/22/2022] Open
Abstract
Urea transporters UT-A2 and UT-B are expressed in epithelia of thin descending limb of Henle's loop and in descending vasa recta, respectively. To study their role and possible interaction in the context of the urine concentration mechanism, a UT-A2 and UT-B double knockout (UT-A2/B knockout) mouse model was generated by targeted deletion of the UT-A2 promoter in embryonic stem cells with UT-B gene knockout. The UT-A2/B knockout mice lacked detectable UT-A2 and UT-B transcripts and proteins and showed normal survival and growth. Daily urine output was significantly higher in UT-A2/B knockout mice than that in wild-type mice and lower than that in UT-B knockout mice. Urine osmolality in UT-A2/B knockout mice was intermediate between that in UT-B knockout and wild-type mice. The changes in urine osmolality and flow rate, plasma and urine urea concentration, as well as non-urea solute concentration after an acute urea load or chronic changes in protein intake suggested that UT-A2 plays a role in the progressive accumulation of urea in the inner medulla. These results suggest that in wild-type mice UT-A2 facilitates urea absorption by urea efflux from the thin descending limb of short loops of Henle. Moreover, UT-A2 deletion in UT-B knockout mice partially remedies the urine concentrating defect caused by UT-B deletion, by reducing urea loss from the descending limbs to the peripheral circulation; instead, urea is returned to the inner medulla through the loops of Henle and the collecting ducts.
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Affiliation(s)
- Tianluo Lei
- Dept. of Pharmacology, School of Basic Medical Sciences, Peking University, 38 Xueyuan Lu, Haidian District, Beijing, China
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Testani JM, Cappola TP, Brensinger CM, Shannon RP, Kimmel SE. Interaction between loop diuretic-associated mortality and blood urea nitrogen concentration in chronic heart failure. J Am Coll Cardiol 2011; 58:375-82. [PMID: 21757114 DOI: 10.1016/j.jacc.2011.01.052] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 12/02/2010] [Accepted: 01/02/2011] [Indexed: 01/31/2023]
Abstract
OBJECTIVES The purpose of this study was to investigate whether a surrogate for renal neurohormonal activation, blood urea nitrogen (BUN), could identify patients destined to experience adverse outcomes associated with the use of high-dose loop diuretics (HDLD). BACKGROUND Loop diuretics are commonly used to control congestive symptoms in heart failure; however, these agents cause neurohormonal activation and have been associated with worsened survival. METHODS Subjects in the BEST (Beta-Blocker Evaluation of Survival Trial) receiving loop diuretics at baseline were analyzed (N = 2,456). The primary outcome was the interaction between BUN- and HDLD-associated mortality. RESULTS In the overall cohort, HDLD use (≥160 mg/day) was associated with increased mortality (hazard ratio [HR]: 1.56; 95% confidence interval [CI]: 1.35 to 1.80). However, after extensively controlling for baseline characteristics, this association did not persist (HR: 1.06; 95% CI: 0.89 to 1.25). In subjects with BUN levels above the median (21.0 mg/dl), both the unadjusted (HR: 1.59; 95% CI: 1.34 to 1.88) and adjusted (HR: 1.29; 95% CI: 1.07 to 1.60) risk of death was higher in the HDLD group. In patients with BUN levels below the median, there was no associated risk with HDLD (HR: 0.99; 95% CI: 0.75 to 1.34) and after controlling for baseline characteristics, the HDLD group had significantly improved survival (HR: 0.71; 95% CI: 0.49 to 0.96) (p interaction = 0.018). CONCLUSIONS The risk associated with HDLD use is strongly dependent on BUN concentrations with reduced survival in patients with an elevated BUN level and improved survival in patients with a normal BUN level. These data suggest a role for neurohormonal activation in loop diuretic-associated mortality.
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Affiliation(s)
- Jeffrey M Testani
- Department of Medicine, Cardiovascular Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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Testani JM, Coca SG, Shannon RP, Kimmel SE, Cappola TP. Influence of renal dysfunction phenotype on mortality in the setting of cardiac dysfunction: analysis of three randomized controlled trials. Eur J Heart Fail 2011; 13:1224-30. [PMID: 21926073 DOI: 10.1093/eurjhf/hfr123] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Renal neurohormonal activation leading to a reduction in glomerular filtration rate (GFR) has been suggested as a mechanism for renal insufficiency (RI) in the setting of heart failure. We hypothesized that RI occurring in the presence of renal neurohormonal activation may be prognostically more important than RI in the absence of renal neurohormonal activation. METHODS AND RESULTS Subjects in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial (n = 429), Beta-Blocker Evaluation of Survival Trial (BEST) (n = 2691), and Studies Of Left Ventricular Dysfunction (SOLVD) trial (n = 6782) limited datasets were studied. The blood urea nitrogen to creatinine ratio (BUN/Creatinine) was employed as a surrogate for renal neurohormonal activation and the primary outcome was the interaction between BUN/Creatinine and RI associated mortality. Baseline RI (GFR < 60 mL/min/1.73 m²) was associated with mortality in all study populations (P < 0.001). In patients with higher BUN/Creatinine, the risk of mortality was consistently greater in patients with RI [adjusted hazard ratio (HR) ESCAPE = 2.8, 95% confidence interval (CI) 1.3-14.3, P = 0.019; BEST = 1.6, 95% CI 1.2-2.2, P = 0.002; SOLVD = 1.6, 95% CI 1.3-2.0, P = 0.001]. However, in patients with lower BUN/Creatinine, the risk of mortality was not elevated in patients with RI (adjusted HR ESCAPE = 0.94, 95% CI 0.35-2.4, P = 0.90, P interaction = 0.005; BEST = 0.97, 95% CI 0.64-1.4, P = 0.90, P interaction = 0.02; SOLVD = 1.0, 95% CI 0.8-1.3, P = 0.71, P interaction = 0.005). CONCLUSION The association between RI and poor survival observed in heart failure populations appears to be contingent not simply on the presence of a reduced GFR, but possibly on the mechanism by which GFR is reduced.
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Affiliation(s)
- Jeffrey M Testani
- Department of Medicine, Cardiovascular Division, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
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Fenton RA, Praetorius J. Molecular Physiology of the Medullary Collecting Duct. Compr Physiol 2011; 1:1031-56. [DOI: 10.1002/cphy.c100064] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kazory A. Emergence of blood urea nitrogen as a biomarker of neurohormonal activation in heart failure. Am J Cardiol 2010; 106:694-700. [PMID: 20723648 DOI: 10.1016/j.amjcard.2010.04.024] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 04/07/2010] [Accepted: 04/07/2010] [Indexed: 11/27/2022]
Abstract
The nonosmotic release of arginine vasopressin, concurrent with the activation of the sympathetic nervous system and renin-angiotensin-aldosterone system, is thought to represent the maladaptive response that is central to the pathophysiology of heart failure (HF). The degree of neurohormonal activation correlates with the severity of the disease and can predict the outcomes. However, quantification of components of neurohormonal axis (e.g., serum arginine vasopressin level) is mainly reserved for research purposes rather than routine practice. The results of several recent HF trials have shed light on the differential role of blood urea nitrogen (BUN) and creatinine in predicting the outcomes in this setting. These studies suggest that BUN could indeed represent a surrogate marker for "renal response" to neurohormonal activation in this setting, above and beyond its role in the estimation of renal function. In this report, the relevant physiologic mechanisms underlying urea and water transport in the kidney are first reviewed. Then, the activation of the neurohormonal axis and the impact of its components on renal urea transport, independent of changes in renal function, are explained. Finally, the unique role of BUN as a biomarker of neurohormonal activation in the setting of HF is discussed, and the potential clinical implication of this novel concept is emphasized. In conclusion, this review explains the pathophysiologic basis for the emerging role of BUN as a biomarker in HF.
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Abstract
Vasopressin promotes renal water reabsorption decreasing excretion of free water to dilute plasma and lower serum osmolality. We have good understanding of the causes, mechanisms and consequences of this vasopressin-dependent renal water movement. In comparison, vasopressin actions on renal electrolytes including sodium excretion and its consequences have been less well understood. This is so for investigation and discussions of the renal actions of vasopressin are framed primarily around water metabolism rather than any direct effect on salt handling. The fact that water moves in biological systems, to include the mammalian kidney, only by osmosis passively down its concentration gradient is implicit in such discussion but often not overtly addressed. This can cause confusion. Moreover, although vasopressin action on renal sodium excretion via the V2 receptor is critical to water transport, it is masked easily being situational--for instance, dependent on hydration state. It is now clear that an increase in sodium reabsorption along the distal nephron (CNT + CD) mediated by activation of the epithelial Na(+) channel (ENaC) by vasopressin makes an important contribution to maintenance of the axial corticomedullary osmotic gradient necessary for maximal water reabsorption. Thus, we need to modify slightly our understanding of vasopressin and its renal actions to include the idea that while vasopressin decreases free water excretion to dilute plasma, it does this, in part, by promoting sodium reabsorption and consequently decreasing sodium excretion via ENaC activated along the distal nephron.
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Hoorn EJ, Zillikens MC, Pols HAP, Danser AHJ, Boomsma F, Zietse R. Osmomediated natriuresis in humans: the role of vasopressin and tubular calcium sensing. Nephrol Dial Transplant 2009; 24:3326-33. [DOI: 10.1093/ndt/gfp303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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