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R Jen BA, Storm AC, Larsen M, Kristensen NB. Effects of sodium chloride intake on urea-N recycling and renal urea-N kinetics in lactating Holstein cows. J Dairy Sci 2024:S0022-0302(24)00954-8. [PMID: 38908713 DOI: 10.3168/jds.2024-24921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 05/29/2024] [Indexed: 06/24/2024]
Abstract
The effects of high (2.5% of DM) versus normal dietary sodium chloride (NaCl) intake on renal urea-N kinetics and urea-N metabolism were investigated in 9 rumen-cannulated and multi-catheterized lactating dairy cows in a crossover design with 21-d periods. It was hypothesized that urinary urea-N excretion would be greater, and blood urea-N concentration lower in response to greater diuresis induced by high NaCl intake. Also, urea-N transport across ruminal and portal drained viscera (PDV) tissues was hypothesized to be affected by dietary sodium intake. A second experiment was conducted using 8 lactating cows in a crossover design with 14-d periods to test high NaCl (2.5% of DM) versus high KCl (3.2% of DM) intake on milk yield and milk urea-N concentrations. Experiment 1 showed that despite greater diuresis there was no effect of high NaCl intake on urinary urea-N excretion or blood urea-N concentration. The high NaCl intake did not affect rumen ammonia concentrations, total rumen VFA concentrations, ruminal venous - arterial concentration differences for ammonia, or ammonia absorption indicating that high NaCl did not adversely affect ruminal fermentation and microbial protein synthesis. High NaCl intake did not affect the total amount of urea-N transport from blood to gut, but ruminal venous - arterial concentration differences for urea-N were lower with high NaCl and ruminal extraction of arterial urea-N was numerically smaller, indicating that the ruminal epithelial urea-N transport was lower with high NaCl. Energy corrected milk yield was greater with high NaCl (3.2 ± 1.5 kg/d); however, milk urea-N concentrations were not affected by treatment. In experiment 2, ECM was greater with NaCl (1.4 ± 0.31 kg/d) compared with KCl (30.2 and 28.8 ± 0.91 kg ECM / d, respectively). Milk urea-N concentration was lower with KCl, suggesting a urea-N lowering effect in milk not evident with high NaCl intake. In conclusion, the present data show that dietary Na intake of 12-13 g/kg DM was followed by greater diuresis but did not impact urea-N excretion or blood urea-N concentration. High NaCl intake did not affect the total amount of urea-N transfer across PDV tissues. Energy corrected milk yield was greater with high NaCl compared with both control and feeding KCl, however, with KCl milk urea-N decreased.
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Affiliation(s)
- B A R Jen
- Department of Animal and Veterinary Sciences, Aarhus University, DK-8830 Tjele, Denmark
| | - A C Storm
- Department of Animal and Veterinary Sciences, Aarhus University, DK-8830 Tjele, Denmark
| | - M Larsen
- Department of Animal and Veterinary Sciences, Aarhus University, DK-8830 Tjele, Denmark
| | - N B Kristensen
- Department of Animal and Veterinary Sciences, Aarhus University, DK-8830 Tjele, Denmark.
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2
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Bankir L, Crambert G, Vargas-Poussou R. The SLC6A18 Transporter Is Most Likely a Na-Dependent Glycine/Urea Antiporter Responsible for Urea Secretion in the Proximal Straight Tubule: Influence of This Urea Secretion on Glomerular Filtration Rate. Nephron Clin Pract 2024:1-27. [PMID: 38824912 DOI: 10.1159/000539602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 05/25/2024] [Indexed: 06/04/2024] Open
Abstract
BACKGROUND Urea is the major end-product of protein metabolism in mammals. In carnivores and omnivores, a large load of urea is excreted daily in urine, with a concentration that is 30-100 times above that in plasma. This is important for the sake of water economy. Too little attention has been given to the existence of energy-dependent urea transport that plays an important role in this concentrating activity. SUMMARY This review first presents functional evidence for an energy-dependent urea secretion that occurs exclusively in the straight part of the proximal tubule (PST). Second, it proposes a candidate transmembrane transporter responsible for this urea secretion in the PST. SLC6A18 is expressed exclusively in the PST and has been identified as a glycine transporter, based on findings in SLC6A18 knockout mice. We propose that it is actually a glycine/urea antiport, secreting urea into the lumen in exchange for glycine and Na. Glycine is most likely recycled back into the cell via a transporter located in the brush border. Urea secretion in the PST modifies the composition of the tubular fluid in the thick ascending limb and, thus, contributes, indirectly, to influence the "signal" at the macula densa that plays a crucial role in the regulation of the glomerular filtration rate (GFR) by the tubulo-glomerular feedback. KEY MESSAGES Taking into account this secondary active secretion of urea in the mammalian kidney provides a new understanding of the influence of protein intake on GFR, of the regulation of urea excretion, and of the urine-concentrating mechanism.
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Affiliation(s)
- Lise Bankir
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM UMRS 1138, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228, Unité Métabolisme et Physiologie Rénale, Centre de Recherche des Cordeliers, Paris, France
| | - Gilles Crambert
- Laboratoire de Physiologie Rénale et Tubulopathies, Centre de Recherche des Cordeliers, INSERM UMRS 1138, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228, Unité Métabolisme et Physiologie Rénale, Centre de Recherche des Cordeliers, Paris, France
| | - Rosa Vargas-Poussou
- CNRS EMR 8228, Unité Métabolisme et Physiologie Rénale, Centre de Recherche des Cordeliers, Paris, France
- Service de Médecine Génomique des Maladies Rares, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, MARHEA, Hôpital Européen Georges Pompidou, Paris, France
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3
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Shi H, Liu Y, Yang D, Liang P, Chen C, Luan H, Shi C. Inverted U-shaped associations between serum uric acid and fasting - plasma glucose level in non-diabetic, pre-diabetic, and diabetic adults: A population-based study in China. J Diabetes Investig 2024; 15:483-490. [PMID: 38108582 PMCID: PMC10981146 DOI: 10.1111/jdi.14132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/19/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023] Open
Abstract
OBJECTIVE This study was designed to examine the correlation between serum uric acid (SUA) and fasting plasma glucose (FPG) levels across non-diabetic, pre-diabetic, and diabetic adults from Northwest China. MATERIALS AND METHODS This study utilized data from a cross-sectional survey conducted in Ningxia Hui Autonomous Region, which investigated the prevalence and risk factors of cardiovascular disease. All subjects underwent tests for SUA and FPG levels. Generalized additive models and two-piecewise linear regression models were applied to explore the relationships between SUA and FPG level. The triglyceride-glucose (TyG) index was examined as a measure of insulin resistance, with an analysis of its mediating effects on the association between SUA and FPG level. RESULTS A total of 10,217 individuals aged 18 and over were included. Generalized additive models verified the inverted U-shaped association between SUA and FPG levels, and the inflection points of FPG levels in the curves were 6.5 mmol/L in males and 8.8 mmol/L in females. The TyG index is an intermediate variable in the relationship between SUA levels and elevated FPG levels, with mediating effects of 12.82% (P < 0.001) for males and 34.02% (P < 0.001) for females. CONCLUSIONS An inverted U-shaped association between FPG and SUA levels was observed in both genders. The threshold of FPG level was lower in males than in females. The relationship between these variables seems to be partially mediated by serum insulin levels.
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Affiliation(s)
- Hongjuan Shi
- School of Public HealthNingxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina
| | - Yining Liu
- People's Hospital of Ningxia Hui Autonomous RegionNingxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina
| | - Danyu Yang
- People's Hospital of Ningxia Hui Autonomous RegionNingxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina
| | - Peifeng Liang
- People's Hospital of Ningxia Hui Autonomous RegionNingxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina
| | - Chen Chen
- People's Hospital of Ningxia Hui Autonomous RegionNingxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina
| | - Hong Luan
- People's Hospital of Ningxia Hui Autonomous RegionNingxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina
| | - Chao Shi
- People's Hospital of Ningxia Hui Autonomous RegionNingxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina
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Afolabi OB, Olasehinde OR, Olaoye OA, Jaiyesimi KF, Ekakitie IL, Oloyede OI. Nephroprotective Effects of Caffeine, Vanillin, and Their Combination against Experimental AlCl 3-Induced Renal Toxicity in Adult Male Wistar Rats. Biochem Res Int 2023; 2023:6615863. [PMID: 37649570 PMCID: PMC10465259 DOI: 10.1155/2023/6615863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/14/2023] [Accepted: 08/14/2023] [Indexed: 09/01/2023] Open
Abstract
Aluminum (Al) is known to be a nephrotoxic metal that can cause renal toxicity in both humans and animals. The use of functional foods has been reported to have significance in managing the toxic effects associated with such metals. This study aimed to assess the potential protective effects of caffeine, vanillin, and their combination in mitigating AlCl3-induced renal toxicity in adult male Wistar rats. A total of thirty (30) adult male Wistar rats weighing between 150 and 200 g were randomly divided into five groups, each consisting of six rats (n = 6). Group 1 served as the control, while the remaining treatment groups received a daily oral dose of 100 mg/kg AlCl3 for a duration of 21 days. In addition, groups 3-5 were coadministered 50 mg/kg body weight (bw) of caffeine, vanillin, and a combination (50/50 mg/kg bw) of both substances, respectively. In the results, AlCl3-treated showed a significant (p < 0.05) increase in serum biomarkers such as ALT, ALP, urea, and creatinine, and a significant (p < 0.05) decrease in serum total proteins (TPs). The renal tissue's antioxidant system, including SOD, CAT, GPx, and GSH, exhibited a significant (p < 0.05) reduction, accompanied by an elevated MDA level. However, the administration of caffeine, vanillin, and their combination resulted in a significant (p < 0.05) decrease in serum ALT, ALP, urea, and creatinine, and a significant (p < 0.05) increase in serum TP. Furthermore, following the treatment, there was a significant (p < 0.05) increase in renal SOD, CAT, GPx, and GSH levels, along with a reduction in the MDA level. In addition, the treatment for 21 days caused a significant (p < 0.05) reversal to the altered histomorphological architecture. These findings suggest that caffeine, vanillin, and their combination could potentially be an effective regimen in managing AlCl3-induced renal toxicity.
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Affiliation(s)
- Olakunle Bamikole Afolabi
- Department of Chemical Sciences, Biochemistry Programme, College of Science, Afe Babalola University, P.M.B 5454, Ado-Ekiti, Ekiti State, Nigeria
| | - Oluwaseun Ruth Olasehinde
- Department of Medical Biochemistry, College of Medicine and Health Sciences, Afe Babalola University, P.M.B 5454, Ado-Ekiti, Ekiti State, Nigeria
| | - Oyindamola Adeniyi Olaoye
- Department of Chemical Sciences, Biochemistry Programme, College of Science, Afe Babalola University, P.M.B 5454, Ado-Ekiti, Ekiti State, Nigeria
| | - Kikelomo Folake Jaiyesimi
- Department of Chemical Sciences, Biochemistry Programme, College of Science, Afe Babalola University, P.M.B 5454, Ado-Ekiti, Ekiti State, Nigeria
| | - Ilobekemen Lisa Ekakitie
- Department of Chemical Sciences, Biochemistry Programme, College of Science, Afe Babalola University, P.M.B 5454, Ado-Ekiti, Ekiti State, Nigeria
| | - Omotade Ibidun Oloyede
- Department of Biochemistry, Ekiti State University, P.M.B 5363, Ado-Ekiti, Ekiti State, Nigeria
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5
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Xu Y, Wang S, Ma W, Li J, Lu Y, Abulizi A, Sun J, Yang B. An HPLC-MS/MS Method for Pharmacokinetic Study of Y-99: A Novel Diuretic Agent Targeting Urea Transporters. J Chromatogr Sci 2023; 61:552-558. [PMID: 36369644 DOI: 10.1093/chromsci/bmac089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/05/2022] [Accepted: 10/12/2022] [Indexed: 07/20/2023]
Abstract
Y-99, a promising first-in-class diuretic, is a novel urea transporter inhibitor with oral diuretic activity. However, little is known about the pharmacokinetic profiles of Y-99 in experimental animals. In this study, a method of quantitative determination of Y-99 in rat plasma based on high-performance liquid chromatography-tandem mass spectrometry was developed and validated in selectivity, linearity, recovery and matrix effect, accuracy and precision, stability, carry-over and dilution integrity. Chromatographic separation was conducted on an ACQUITY BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with gradient elution at a 0.3 mL/min flow rate after protein precipitation. Mass spectrometry was performed by a positive electrospray ionization mass spectrometer in multiple reaction monitoring mode. The method showed standard-compliant linearity (1-1,000 ng/mL, r = 0.9991). The intra-day and inter-day accuracy (relative error < 11.2%) and precision (coefficient of variation <8.4%) were within acceptable criteria. The recovery and matrix effects were 97.3-110.7% and 103.7-107.5%, respectively. The stability, dilution integrity and carry-over of the method were also within the acceptable criteria. Pharmacokinetic profiles of Y-99 in rats were first investigated using this method, which was vital for developing novel diuretics without electrolyte imbalance targeting urea transporters.
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Affiliation(s)
- Yue Xu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China
| | - Shuyuan Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China
| | - Wen Ma
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Jun Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Yingyuan Lu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Abudumijiti Abulizi
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China
| | - Jianguo Sun
- Key Lab of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China
| | - Baoxue Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China
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Sun M, Li D, Hua M, Miao X, Su Y, Chi Y, Li Y, Sun R, Niu H, Wang J. Black bean husk and black rice anthocyanin extracts modulated gut microbiota and serum metabolites for improvement in type 2 diabetic rats. Food Funct 2022; 13:7377-7391. [PMID: 35730792 DOI: 10.1039/d2fo01165d] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Black rice and black bean have not yet been fully investigated as healthy foods for their therapeutic effects on type 2 diabetes mellitus (T2DM). In this study, we aimed to evaluate the antidiabetic effects of black rice, black bean husk anthocyanin extracts, and their combination on glycolipid metabolism, gut microbiota, and serum metabolites in T2DM rats. Black bean husk and black rice anthocyanin extracts were administered to T2DM rats by gavage for 4 weeks. The results showed that black rice and black bean husk anthocyanin extracts significantly improved blood glucose, insulin resistance, serum oxidative stress state, lipid metabolism and inflammatory cytokines levels in rats, and alleviated liver damage. Black rice and black bean husk anthocyanin extracts increased the abundance of short-chain fatty acid (SCFA) producing bacteria Akkermansia spp., Phascolarctobacterium spp., Bacteroides spp., and Coprococcus spp., changed the gut microbiota structure; activated AMPK, PI3K, and AKT; inhibited HMGCR, G6pase and PEPCK expression; and inhibited hepatic gluconeogenesis. Moreover, by adjusting the levels of urea, deoxycytidine, L-citrulline, pseudouridine, and other serum metabolites in T2DM rats, the arginine biosynthesis and pyrimidine metabolism pathways were downregulated. The above results indicated that black rice and black bean husk anthocyanin extracts had a significant impact on the development of T2DM.
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Affiliation(s)
- Mubai Sun
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
| | - Da Li
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
| | - Mei Hua
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
| | - Xinyu Miao
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
| | - Ying Su
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
| | - Yanping Chi
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
| | - Yueqiao Li
- Department of International Cooperation, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China
| | - Ruiyue Sun
- Department of Food Science and Engineering, College of Agriculture, Yanbian University, Yanji, 133000, Jilin, China
| | - Honghong Niu
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
| | - Jinghui Wang
- Institute of Agro-food Technology, Jilin Academy of Agricultural Sciences, 130033, Changchun, Jilin, China.
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7
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Xu Y, Zhang H, Li N, Ma W, Wang S, Sun J, Yang B. Preclinical Pharmacokinetic Studies of a Novel Diuretic Inhibiting Urea Transporters. Molecules 2022; 27:2451. [PMID: 35458649 PMCID: PMC9027532 DOI: 10.3390/molecules27082451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/02/2022] [Accepted: 04/07/2022] [Indexed: 11/16/2022] Open
Abstract
Urea transporter (UT) inhibitors are a class of promising novel diuretics that do not cause the imbalance of Na+, K+, Cl-, and other electrolytes. In our previous studies, 25a, a promising diuretic candidate inhibiting UT, was discovered and showed potent diuretic activities in rodents. Here, a sensitive liquid chromatography-tandem mass spectrometry method for the quantitation of 25a in rat plasma, urine, feces, bile, and tissue homogenates was developed and validated to support the preclinical pharmacokinetic studies. The tissue distribution, excretion, and plasma protein binding were investigated in rats. After a single oral dose of 25a at 25, 50, and 100 mg/kg, the drug exposure increased linearly with the dose. The drug accumulation was observed after multiple oral doses compared to a single dose. In the distribution study, 25a exhibited a wide distribution to tissues with high blood perfusion, such as kidney, heart, lung, and spleen, and the lowest distribution in the brain and testis. The accumulative excretion rate of 25a was 0.14%, 3.16%, and 0.018% in urine, feces, and bile, respectively. The plasma protein binding of 25a was approximately 60% in rats and 40% in humans. This is the first study on the preclinical pharmacokinetic profiles of 25a.
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Affiliation(s)
- Yue Xu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.X.); (H.Z.); (N.L.); (S.W.)
| | - Hang Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.X.); (H.Z.); (N.L.); (S.W.)
| | - Nannan Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.X.); (H.Z.); (N.L.); (S.W.)
| | - Wen Ma
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China;
| | - Shuyuan Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.X.); (H.Z.); (N.L.); (S.W.)
| | - Jianguo Sun
- Key Lab of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang Street, Nanjing 210009, China;
| | - Baoxue Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.X.); (H.Z.); (N.L.); (S.W.)
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8
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Geiger AK, Weber LP. Assessing non-protein nitrogen sources in commercial dry dog foods. Transl Anim Sci 2022; 6:txac009. [PMID: 35233511 PMCID: PMC8882255 DOI: 10.1093/tas/txac009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Indexed: 11/26/2022] Open
Abstract
Protein is a macronutrient required by dogs for growth and maintenance metabolism. However, a portion of the crude protein listed on pet foods may actually arise from non-digestible organic nitrogen or potentially toxic inorganic non-protein nitrogen sources. Neither non-protein source is retained or used by the animal. However, these compounds may result in adverse effects such as methemoglobin formation and increased oxidative stress or potentially beneficial effects such as improved vascular distensibility and decreased inflammation. To analyze nitrogen retention and screen for non-protein nitrogen, four commercial, dry kibble dog foods and one laboratory-made diet were evaluated and then fed to beagles during two separate feeding trials. During the first trial, dogs were randomly assigned each diet (n = 4 dogs/diet) and fed chromium oxide-coated diets for 48 h, followed by total urine and marked fecal collection, as well as plasma collection for total nitrogen, nitrate, ammonia, and urea determination. The amount of nitrogen retained (93%–96%) did not differ among commercial diets. Protein total tract apparent digestibility (TTAD) ranged from 69% to 84%, with the high protein diets significantly higher than the laboratory-made and mid-ranged diets (1-way ANOVA: P < 0.05). The high protein diet also contained the highest concentration of nitrate with subsequent elevations in plasma nitrotyrosine levels (indicator of oxidative stress). During the second trial, eight dogs (n = 8) were fed the same diets for 6 d, after which echocardiography was completed with blood, urine, and feces collected. For health end-points, methemoblobin, plasma nitrotyrosine, and C-reactive protein (CRP; indicator of inflammation) levels were measured. Methemoglobin levels were significantly lower in the high protein diet (P > 0.05), possible due to the stimulation of methemoglobin reductase while nitrotyrosine was unchanged and CRP was undetectable. Furthermore, there was a positive relationship between crude protein, crude fat (simple linear regression: P = 0.02, r2 > 0.6), price (P = 0.08, r2 > 0.6), and caloric density (P = 0.11, r2 > 0.6). There were no significant cardiovascular differences among any of the diets (P > 0.05). Ultimately, this study shows that in commercial diets, price does reflect protein content but that feeding dogs high protein diets for a long period of time may provide an excess in calories without a change in cardiovascular function or detectable increases in inflammation.
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Affiliation(s)
- Andrea K Geiger
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lynn P Weber
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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9
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Vallon V, Nakagawa T. Renal Tubular Handling of Glucose and Fructose in Health and Disease. Compr Physiol 2021; 12:2995-3044. [PMID: 34964123 PMCID: PMC9832976 DOI: 10.1002/cphy.c210030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The proximal tubule of the kidney is programmed to reabsorb all filtered glucose and fructose. Glucose is taken up by apical sodium-glucose cotransporters SGLT2 and SGLT1 whereas SGLT5 and potentially SGLT4 and GLUT5 have been implicated in apical fructose uptake. The glucose taken up by the proximal tubule is typically not metabolized but leaves via the basolateral facilitative glucose transporter GLUT2 and is returned to the systemic circulation or used as an energy source by distal tubular segments after basolateral uptake via GLUT1. The proximal tubule generates new glucose in metabolic acidosis and the postabsorptive phase, and fructose serves as an important substrate. In fact, under physiological conditions and intake, fructose taken up by proximal tubules is primarily utilized for gluconeogenesis. In the diabetic kidney, glucose is retained and gluconeogenesis enhanced, the latter in part driven by fructose. This is maladaptive as it sustains hyperglycemia. Moreover, renal glucose retention is coupled to sodium retention through SGLT2 and SGLT1, which induces secondary deleterious effects. SGLT2 inhibitors are new anti-hyperglycemic drugs that can protect the kidneys and heart from failing independent of kidney function and diabetes. Dietary excess of fructose also induces tubular injury. This can be magnified by kidney formation of fructose under pathological conditions. Fructose metabolism is linked to urate formation, which partially accounts for fructose-induced tubular injury, inflammation, and hemodynamic alterations. Fructose metabolism favors glycolysis over mitochondrial respiration as urate suppresses aconitase in the tricarboxylic acid cycle, and has been linked to potentially detrimental aerobic glycolysis (Warburg effect). © 2022 American Physiological Society. Compr Physiol 12:2995-3044, 2022.
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Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, California, USA,Department of Pharmacology, University of California San Diego, La Jolla, California, USA,VA San Diego Healthcare System, San Diego, California, USA,Correspondence to and
| | - Takahiko Nakagawa
- Division of Nephrology, Rakuwakai-Otowa Hospital, Kyoto, Japan,Correspondence to and
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10
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Nandi S, Sanyal S, Amin SA, Kashaw SK, Jha T, Gayen S. Urea transporter and its specific and nonspecific inhibitors: State of the art and pharmacological perspective. Eur J Pharmacol 2021; 911:174508. [PMID: 34536365 DOI: 10.1016/j.ejphar.2021.174508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 01/11/2023]
Abstract
Hypertension is a major concern for a wide array of patients. The traditional drugs are commonly referred as 'water pills' and these molecules have been successful in alleviating hypertension. However, this comes at the high expense of precious electrolytes in our body. To dissipate this major adverse effect, the urea transporter inhibitors play especially important roles in maintaining the fluid balance by maintaining the concentration of urea in the inner medullary collecting duct. The purpose of this communication is to provide insights into the structural feature of these target proteins and inhibition of both urea transporter types A (UT-A) and B (UT-B) selectively and non-selectively with a special focus on the UT-A inhibitors as they are the primary target for diuresis. It was observed that a wide class of drugs such as thiourea analogues, 2,7-disubstituted fluorenones can inhibit both the protein non-selectively whereas 8-hydroxyquinoline, aminothiazolone, 1,3,5-triazine, triazolothienopyrimidine, thienoquinoline, arylthiazole, γ-sultambenzosulfonamide and 1,2,4-triazoloquinoxaline classes of compounds inhibit UT-A. The goal of this study is to highlight the important aspects that may be useful to understanding the perspectives of urea transporter inhibitors in rational drug discovery.
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Affiliation(s)
- Sudipta Nandi
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, MP, India
| | - Saptarshi Sanyal
- School of Pharmaceutical Technology, Adamas University, Kolkata, India; Natural Science Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India
| | - Sk Abdul Amin
- Natural Science Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India
| | - Sushil Kumar Kashaw
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, MP, India
| | - Tarun Jha
- Natural Science Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
| | - Shovanlal Gayen
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, MP, India; Laboratory of Drug Design and Discovery, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
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11
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Bankir L. Could an intrarenal Cori cycle participate in the urinary concentrating mechanism? Am J Physiol Renal Physiol 2021; 321:F352-F353. [PMID: 34460352 DOI: 10.1152/ajprenal.00253.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Lise Bankir
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
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12
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Souza VC, Aguilar M, Van Amburgh M, Nayananjalie WAD, Hanigan MD. Milk urea nitrogen variation explained by differences in urea transport into the gastrointestinal tract in lactating dairy cows. J Dairy Sci 2021; 104:6715-6726. [PMID: 33773787 DOI: 10.3168/jds.2020-19787] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/13/2021] [Indexed: 01/30/2023]
Abstract
Milk urea nitrogen (MUN) and blood urea nitrogen are correlated with nitrogen balance and nitrogen excretion; however, there is also a genetic component to MUN concentrations that could be associated with differences in urea transport. It was hypothesized that a portion of the variation in MUN concentrations among cows is caused by variation in gastrointestinal and kidney urea clearance rates. Eight lactating cows with varying MUN concentrations while fed a common diet were infused with [15N15N]urea to determine urea N entry rate (UER), gastrointestinal entry rate, returned to ornithine cycle, urea N used for anabolism, urea N excretion in feces and urine. Urea clearance rates by the kidneys and gastrointestinal tract were calculated from isotopic enrichment of urea excretion in urine and gut entry rate, respectively, and plasma urea N concentrations (PUN). Over the course of the experiment, animals weighed an average of 506 ± 62 kg and produced 26.3 ± 4.39 kg of milk/d, with MUN concentrations ranging from 11.6 to 17.3 mg/dL (average of 14.9 ± 2.1 mg/dL). Plasma urea N was positively correlated with UER, urea N excretion in urine, and urea N used for anabolism. Plasma urea N and MUN were negatively correlated with gut clearance rates and ratio of gastrointestinal entry rate to UER. This relationship supports the hypothesis that differences in gut urea transport activity among animals causes variation in PUN and MUN concentrations, and that cows with high PUN and MUN are less efficient at recycling PUN to the gastrointestinal tract and thus may be more susceptible to ruminal N deficiencies when fed low RDP diets. Such biological variation in urea metabolism necessitates an adequate safety margin when setting regulations for maximal MUN levels as an indicator of herd N efficiency.
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Affiliation(s)
- V C Souza
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061
| | - M Aguilar
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061
| | - M Van Amburgh
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - W A D Nayananjalie
- Department of Animal and Food Sciences, Faculty of Agriculture, Rajarata University of Sri Lanka, Puliyankulama, Anuradhapura, Sri Lanka 61316
| | - M D Hanigan
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061.
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13
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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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14
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Vallon V. Glucose transporters in the kidney in health and disease. Pflugers Arch 2020; 472:1345-1370. [PMID: 32144488 PMCID: PMC7483786 DOI: 10.1007/s00424-020-02361-w] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 02/06/2023]
Abstract
The kidneys filter large amounts of glucose. To prevent the loss of this valuable fuel, the tubular system of the kidney, particularly the proximal tubule, has been programmed to reabsorb all filtered glucose. The machinery involves the sodium-glucose cotransporters SGLT2 and SGLT1 on the apical membrane and the facilitative glucose transporter GLUT2 on the basolateral membrane. The proximal tubule also generates new glucose, particularly in the post-absorptive phase but also to enhance bicarbonate formation and maintain acid-base balance. The glucose reabsorbed or formed by the proximal tubule is primarily taken up into peritubular capillaries and returned to the systemic circulation or provided as an energy source to further distal tubular segments that take up glucose by basolateral GLUT1. Recent studies provided insights on the coordination of renal glucose reabsorption, formation, and usage. Moreover, a better understanding of renal glucose transport in disease states is emerging. This includes the kidney in diabetes mellitus, when renal glucose retention becomes maladaptive and contributes to hyperglycemia. Furthermore, enhanced glucose reabsorption is coupled to sodium retention through the sodium-glucose cotransporter SGLT2, which induces secondary deleterious effects. As a consequence, SGLT2 inhibitors are new anti-hyperglycemic drugs that can protect the kidneys and heart from failing. Recent studies discovered unique roles for SGLT1 with implications in acute kidney injury and glucose sensing at the macula densa. This review discusses established and emerging concepts of renal glucose transport, and outlines the need for a better understanding of renal glucose handling in health and disease.
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Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA.
- VA San Diego Healthcare System, San Diego, CA, USA.
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15
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Okabe T, Katoh M, Kano M, Okazaki R, Tanaka Y, Toyoda H, Ueno M. [Studies of the Various Chronic Kidney Failure Rat Models and Hemodialysis Mini-pig Model for the Evaluation of Anti-hyperphosphatemia Drugs]. YAKUGAKU ZASSHI 2019; 139:1435-1448. [PMID: 31685740 DOI: 10.1248/yakushi.19-00082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Animal models of chronic kidney failure (CKF) have been developed for the pharmacodynamic evaluation of various phosphate binders that are used clinically to treat hyperphosphatemia in patients with chronic kidney disease. However, these models represent different disease states and severities, depending on the experimental conditions and are not clearly defined for pharmacological evaluation. In addition, experimental models have not yet been established for artificial dialysis. The purpose of this study was to confirm the utility of the various rat models of CKF and the mini-pig model of hemodialysis as models of hyperphosphatemia for pharmacodynamic evaluation. Various rat models of pre-dialysis CKF (oral adenine dosing, 5/6 resection, and ligation nephrectomy model) were evaluated through determinations of serum and urinary parameters (osmolality, creatinine, and phosphorus), pathological observations of kidney, and the phosphorus-absorbing properties of lanthanum carbonate (La) formulations. The rat and mini-pig models were compared based on each evaluation index. In the oral adenine dosing model, serum phosphorus increased markedly and the area under the serum phosphorus concentration-time curve (phosphorus AUC) decreased in a dose-dependent manner with the administration of La formulations. In contrast, a significant decrease in serum phosphorus AUC, a prolongation of the dialysis interval, and an improvement in dialysis efficiency were observed after administration of La formulations to the mini-pig hemodialysis model. Furthermore, the results of bioequivalence studies between two La formulations (Fosrenol and SW670, a generic formulation) suggested that the rat and mini-pig models are useful and precise as pre-dialysis and dialysis models, respectively.
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Affiliation(s)
- Tomoyuki Okabe
- Biological Research Department, Sawai Pharmaceutical Co., Ltd
| | | | | | - Risa Okazaki
- Biological Research Department, Sawai Pharmaceutical Co., Ltd
| | | | - Hiromu Toyoda
- Biological Research Department, Sawai Pharmaceutical Co., Ltd
| | - Masayoshi Ueno
- Biological Research Department, Sawai Pharmaceutical Co., Ltd
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16
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Wang H, Huang B, Wang W, Li J, Chen Y, Flynn T, Zhao M, Zhou Z, Lin X, Zhang Y, Xu M, Li K, Tian K, Yuan D, Zhou P, Hu L, Zhong D, Zhu S, Li J, Chen D, Wang K, Liang J, He Q, Sun J, Shi J, Yan L, Sands JM, Xie Z, Lian X, Xu D, Ran J, Yang B. High urea induces depression and LTP impairment through mTOR signalling suppression caused by carbamylation. EBioMedicine 2019; 48:478-490. [PMID: 31628020 PMCID: PMC6838447 DOI: 10.1016/j.ebiom.2019.09.049] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/17/2019] [Accepted: 09/17/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Urea, the end product of protein metabolism, has been considered to have negligible toxicity for a long time. Our previous study showed a depression phenotype in urea transporter (UT) B knockout mice, which suggests that abnormal urea metabolism may cause depression. The purpose of this study was to determine if urea accumulation in brain is a key factor causing depression using clinical data and animal models. METHODS A meta-analysis was used to identify the relationship between depression and chronic diseases. Functional Magnetic Resonance Imaging (fMRI) brain scans and common biochemical indexes were compared between the patients and healthy controls. We used behavioural tests, electrophysiology, and molecular profiling techniques to investigate the functional role and molecular basis in mouse models. FINDINGS After performing a meta-analysis, we targeted the relevance between chronic kidney disease (CKD) and depression. In a CKD mouse model and a patient cohort, depression was induced by impairing the medial prefrontal cortex. The enlarged cohort suggested that urea was responsible for depression. In mice, urea was sufficient to induce depression, interrupt long-term potentiation (LTP) and cause loss of synapses in several models. The mTORC1-S6K pathway inhibition was necessary for the effect of urea. Lastly, we identified that the hydrolysate of urea, cyanate, was also involved in this pathophysiology. INTERPRETATION These data indicate that urea accumulation in brain is an independent factor causing depression, bypassing the psychosocial stress. Urea or cyanate carbamylates mTOR to inhibit the mTORC1-S6K dependent dendritic protein synthesis, inducing impairment of synaptic plasticity in mPFC and depression-like behaviour. CKD patients may be able to attenuate depression only by strict management of blood urea.
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Affiliation(s)
- Hongkai Wang
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China; Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Boyue Huang
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Weiling Wang
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Jinfang Li
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yi Chen
- Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Trevor Flynn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Meng Zhao
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zhiming Zhou
- Department of Radiology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaojing Lin
- School of Public Health and Management, Research Center for Medicine and Social Development, Innovation Center for Social Risk Governance in Health, Chongqing Medical University, Chongqing, China
| | - Yinan Zhang
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China; National Institute on Drug Dependence, Peking University, Bejing, China
| | - Mengmeng Xu
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Keqiong Li
- Chongqing Cancer Research Institute, Chongqing, China
| | - Kuan Tian
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Dezhi Yuan
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Peng Zhou
- Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Ling Hu
- Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Dandan Zhong
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Shuai Zhu
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Jing Li
- Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Dilong Chen
- Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China; Chongqing Three Gorges Medical College, Chongqing, China
| | - Kejian Wang
- Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Jianhui Liang
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China; National Institute on Drug Dependence, Peking University, Bejing, China
| | - Qihua He
- Center of Medical and Health Analysis, Peking University, Beijing, China
| | - Jianbin Sun
- Clinical Laboratory, Peking University Third Hospital, Beijing, China
| | - Jie Shi
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China; National Institute on Drug Dependence, Peking University, Bejing, China
| | - Li Yan
- Ion Channel Explorer Bioscience INC., Beijing, China
| | - Jeff M Sands
- Renal Division, Department of Medicine and Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Zhengwei Xie
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Xuemei Lian
- School of Public Health and Management, Research Center for Medicine and Social Development, Innovation Center for Social Risk Governance in Health, Chongqing Medical University, Chongqing, China
| | - Duan Xu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Jianhua Ran
- Department of Anatomy, and Laboratory of Neuroscience and Tissue Engineering, Basic Medical College, Chongqing Medical University, Chongqing, China.
| | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China.
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17
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Phillips AL, Stapleton HM. Inhibition of Human Liver Carboxylesterase (hCE1) by Organophosphate Ester Flame Retardants and Plasticizers: Implications for Pharmacotherapy. Toxicol Sci 2019; 171:396-405. [PMID: 31268531 PMCID: PMC6760270 DOI: 10.1093/toxsci/kfz149] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/02/2019] [Accepted: 06/12/2019] [Indexed: 01/24/2023] Open
Abstract
Organophosphate ester (OPE) flame retardants and plasticizers, consumer product additives with widespread human exposure, were evaluated for their effect on the activity of purified human liver carboxylesterase (hCE1). Four of the 15 OPEs tested had IC50 values lower than 100 nM, including triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPHP), 4-isopropylphenyl diphenyl phosphate (4IPPDPP), and 4-tert-butylphenyl diphenyl phosphate (4tBPDPP), as did 4 of the commercial flame retardant mixtures tested. Because hCE1 is critical for the activation of imidapril, an angiotensin-converting enzyme-inhibitor prodrug prescribed to treat hypertension, the most potent inhibitors, TPHP and 4tBPDPP, and an environmentally relevant mixture (house dust) were further evaluated for their effect on imidapril bioactivation in vitro. TPHP and 4tBPDPP were potent inhibitors of hCE1-mediated imidapril activation (Ki = 49.0 and 17.9 nM, respectively). House dust extracts (100 µg/ml) also caused significant reductions (up to 33%) in imidapril activation. Combined, these data suggest that exposure to OPEs may affect pharmacotherapy.
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Affiliation(s)
- Allison L Phillips
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708-0328
| | - Heather M Stapleton
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708-0328
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18
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Nespoux J, Patel R, Hudkins KL, Huang W, Freeman B, Kim YC, Koepsell H, Alpers CE, Vallon V. Gene deletion of the Na +-glucose cotransporter SGLT1 ameliorates kidney recovery in a murine model of acute kidney injury induced by ischemia-reperfusion. Am J Physiol Renal Physiol 2019; 316:F1201-F1210. [PMID: 30995111 PMCID: PMC6620597 DOI: 10.1152/ajprenal.00111.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/05/2019] [Accepted: 04/10/2019] [Indexed: 12/12/2022] Open
Abstract
Renal Na+-glucose cotransporter SGLT1 mediates glucose reabsorption in the late proximal tubule, a hypoxia-sensitive tubular segment that enters the outer medulla. Gene deletion in mice (Sglt1-/-) was used to determine the role of the cotransporter in acute kidney injury induced by ischemia-reperfusion (IR), including the initial injury and subsequent recovery phase. On days 1 and 16 after IR, absolute and fractional urinary glucose excretion remained greater in Sglt1-/- mice versus wild-type (WT) littermates, consistent with a sustained contribution of SGLT1 to tubular glucose reabsorption in WT mice. Absence of SGLT1 did not affect the initial kidney impairment versus WT mice, as indicated by similar increases on day 1 in plasma concentrations of creatinine and urinary excretion of the tubular injury marker kidney injury molecule-1 as well as a similar rise in plasma osmolality and fall in urine osmolality as indicators of impaired urine concentration. Recovery of kidney function on days 14/16, however, was improved in Sglt1-/- versus WT mice, as indicated by lower plasma creatinine, higher glomerula filtration rate (by FITC-sinistrin in awake mice), and more completely restored urine and plasma osmolality. This was associated with a reduced tubular injury score in the cortex and outer medulla, better preserved renal mRNA expression of tubular transporters (Sglt2 and Na+-K+-2Cl- cotransporter Nkcc2), and a lesser rise in renal mRNA expression of markers of injury, inflammation, and fibrosis [kidney injury molecule-1, chemokine (C-C motif) ligand 2, fibronectin 1, and collagen type I-α1] in Sglt1-/- versus WT mice. These results suggest that SGLT1 activity in the late proximal tubule may have deleterious effects during recovery of IR-induced acute kidney injury and identify SGLT1 as a potential therapeutic target.
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Affiliation(s)
- Josselin Nespoux
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Rohit Patel
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Kelly L Hudkins
- Department of Pathology, University of Washington , Seattle, Washington
| | - Winnie Huang
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Brent Freeman
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Young Chul Kim
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Hermann Koepsell
- Department of Molecular Plant Physiology, University Würzburg , Würzburg , Germany
| | - Charles E Alpers
- Department of Pathology, University of Washington , Seattle, Washington
| | - Volker Vallon
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
- Department of Pharmacology, University of California , San Diego, California
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19
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Chan CYL, Hiong KC, Choo CYL, Boo MV, Wong WP, Chew SF, Ip YK. Increased apical sodium-dependent glucose transporter abundance in the ctenidium of the giant clam Tridacna squamosa upon illumination. ACTA ACUST UNITED AC 2019; 222:jeb.195644. [PMID: 30877228 DOI: 10.1242/jeb.195644] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/05/2019] [Indexed: 01/14/2023]
Abstract
Giant clams contain phototrophic zooxanthellae, and live in nutrient-deficient tropical waters where light is available. We obtained the complete cDNA coding sequence of a homolog of mammalian sodium/glucose cotransporter 1 (SGLT1) - SGLT1-like - from the ctenidium of the fluted giant clam, Tridacna squamosa SGLT1-like had a host origin and was expressed predominantly in the ctenidium. Molecular characterizations reveal that SGLT1-like of T. squamosa could transport urea, in addition to glucose, as other SGLT1s do. It has an apical localization in the epithelium of ctenidial filaments and water channels, and the apical anti-SGLT1-like immunofluorescence was stronger in individuals exposed to light than to darkness. Furthermore, the protein abundance of SGLT1-like increased significantly in the ctenidium of individuals exposed to light for 12 h, although the SGLT1-like transcript level remained unchanged. As expected, T. squamosa could perform light-enhanced glucose absorption, which was impeded by exogenous urea. These results denote the close relationships between light-enhanced glucose absorption and light-enhanced SGLT1-like expression in the ctenidium of T. squamosa Although glucose absorption could be trivial compared with the donation of photosynthates from zooxanthellae in symbiotic adults, SGLT1-like might be essential for the survival of aposymbiotic larvae, leading to its retention in the symbiotic stage. A priori, glucose uptake through SGLT1-like might be augmented by the surface microbiome through nutrient cycling, and the absorbed glucose could partially fulfill the metabolic needs of the ctenidial cells. Additionally, SGLT1-like could partake in urea absorption, as T. squamosa is known to conduct light-enhanced urea uptake to benefit the nitrogen-deficient zooxanthellae.
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Affiliation(s)
- Christabel Y L Chan
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Kum C Hiong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Celine Y L Choo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Mel V Boo
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore .,The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore 119227, Republic of Singapore
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20
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Qi H, Mariager CØ, Nielsen PM, Schroeder M, Lindhardt J, Nørregaard R, Klein JD, Sands JM, Laustsen C. Glucagon infusion alters the hyperpolarized 13 C-urea renal hemodynamic signature. NMR IN BIOMEDICINE 2019; 32:e4028. [PMID: 30426590 DOI: 10.1002/nbm.4028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/13/2018] [Accepted: 09/19/2018] [Indexed: 06/09/2023]
Abstract
Renal urea handling is central to the urine concentrating mechanism, and as such the ability to image urea transport in the kidney is an important potential imaging biomarker for renal functional assessment. Glucagon levels associated with changes in dietary protein intake have been shown to influence renal urea handling; however, the exact mechanism has still to be fully understood. Here we investigate renal function and osmolite distribution using [13 C,15 N] urea dynamics and 23 Na distribution before and 60 min after glucagon infusion in six female rats. Glucagon infusion increased the renal [13 C,15 N] urea mean transit time by 14%, while no change was seen in the sodium distribution, glomerular filtration rate or oxygen consumption. This change is related to the well-known effect of increased urea excretion associated with glucagon infusion, independent of renal functional effects. This study demonstrates for the first time that hyperpolarized 13 C-urea enables monitoring of renal urinary excretion effects in vivo.
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Affiliation(s)
- Haiyun Qi
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Per Mose Nielsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Marie Schroeder
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jakob Lindhardt
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Rikke Nørregaard
- Water Salt Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Janet D Klein
- Renal Division, Department of Medicine, Emory University, Giorgia, USA
| | - Jeff M Sands
- Renal Division, Department of Medicine, Emory University, Giorgia, USA
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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21
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Lee CJ, Gardiner BS, Evans RG, Smith DW. A model of oxygen transport in the rat renal medulla. Am J Physiol Renal Physiol 2018; 315:F1787-F1811. [DOI: 10.1152/ajprenal.00363.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The renal medulla is prone to hypoxia. Medullary hypoxia is postulated to be a leading cause of acute kidney injury, so there is considerable interest in predicting the oxygen tension in the medulla. Therefore we have developed a computational model for blood and oxygen transport within a physiologically normal rat renal medulla, using a multilevel modeling approach. For the top-level model we use the theory of porous media and advection-dispersion transport through a realistic three-dimensional representation of the medulla’s gross anatomy to describe blood flow and oxygen transport throughout the renal medulla. For the lower-level models, we employ two-dimensional reaction-diffusion models describing the distribution of oxygen through tissue surrounding the vasculature. Steady-state model predictions at the two levels are satisfied simultaneously, through iteration between the levels. The computational model was validated by simulating eight sets of experimental data regarding renal oxygenation in rats (using 4 sets of control groups and 4 sets of treatment groups, described in 4 independent publications). Predicted medullary tissue oxygen tension or microvascular oxygen tension for control groups and for treatment groups that underwent moderate perturbation in hemodynamic and renal functions is within ±2 SE values observed experimentally. Diffusive shunting between descending and ascending vasa recta is predicted to be only 3% of the oxygen delivered. The validation tests confirm that the computational model is robust and capable of capturing the behavior of renal medullary oxygenation in both normal and early-stage pathological states in the rat.
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Affiliation(s)
- Chang-Joon Lee
- School of Engineering and Information Technology, Murdoch University, Perth, Western Australia, Australia
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Bruce S. Gardiner
- School of Engineering and Information Technology, Murdoch University, Perth, Western Australia, Australia
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Roger G. Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute, and Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - David W. Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
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22
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Scarfe L, Schock-Kusch D, Ressel L, Friedemann J, Shulhevich Y, Murray P, Wilm B, de Caestecker M. Transdermal Measurement of Glomerular Filtration Rate in Mice. J Vis Exp 2018. [PMID: 30394397 PMCID: PMC6235579 DOI: 10.3791/58520] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Transdermal analysis of glomerular filtration rate (GFR) is an established technique that is used to assess renal function in mouse and rat models of acute kidney injury and chronic kidney disease. The measurement system consists of a miniaturized fluorescence detector that is directly attached to the skin on the back of conscious, freely moving animals, and measures the excretion kinetics of the exogenous GFR tracer, fluorescein-isothiocyanate (FITC) conjugated sinistrin (an inulin analog). This system has been described in detail in rats. However, because of their smaller size, measurement of transcutaneous GFR in mice presents additional technical challenges. In this paper we therefore provide the first detailed practical guide to the use of transdermal GFR monitors in mice based on the combined experience of three different investigators who have been performing this assay in mice over a number of years.
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Affiliation(s)
- Lauren Scarfe
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center; Department of Cellular and Molecular Physiology, University of Liverpool
| | | | - Lorenzo Ressel
- Department of Veterinary Pathology and Public Health, Institute of Veterinary Science, University of Liverpool
| | | | | | - Patricia Murray
- Department of Cellular and Molecular Physiology, University of Liverpool
| | - Bettina Wilm
- Department of Cellular and Molecular Physiology, University of Liverpool;
| | - Mark de Caestecker
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center;
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23
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He Q, Su G, Liu K, Zhang F, Jiang Y, Gao J, Liu L, Jiang Z, Jin M, Xie H. Sex-specific reference intervals of hematologic and biochemical analytes in Sprague-Dawley rats using the nonparametric rank percentile method. PLoS One 2017; 12:e0189837. [PMID: 29261747 PMCID: PMC5738108 DOI: 10.1371/journal.pone.0189837] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/01/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Hematologic and biochemical analytes of Sprague-Dawley rats are commonly used to determine effects that were induced by treatment and to evaluate organ dysfunction in toxicological safety assessments, but reference intervals have not been well established for these analytes. Reference intervals as presently defined for these analytes in Sprague-Dawley rats have not used internationally recommended statistical method nor stratified by sex. Thus, we aimed to establish sex-specific reference intervals for hematologic and biochemical parameters in Sprague-Dawley rats according to Clinical and Laboratory Standards Institute C28-A3 and American Society for Veterinary Clinical Pathology guideline. METHODS Hematology and biochemistry blood samples were collected from 500 healthy Sprague-Dawley rats (250 males and 250 females) in the control groups. We measured 24 hematologic analytes with the Sysmex XT-2100i analyzer, 9 biochemical analytes with the Olympus AU400 analyzer. We then determined statistically relevant sex partitions and calculated reference intervals, including corresponding 90% confidence intervals, using nonparametric rank percentile method. RESULTS We observed that most hematologic and biochemical analytes of Sprague-Dawley rats were significantly influenced by sex. Males had higher hemoglobin, hematocrit, red blood cell count, red cell distribution width, mean corpuscular volume, mean corpuscular hemoglobin, white blood cell count, neutrophils, lymphocytes, monocytes, percentage of neutrophils, percentage of monocytes, alanine aminotransferase, aspartate aminotransferase, and triglycerides compared to females. Females had higher mean corpuscular hemoglobin concentration, plateletcrit, platelet count, eosinophils, percentage of lymphocytes, percentage of eosinophils, creatinine, glucose, total cholesterol and urea compared to males. Sex partition was required for most hematologic and biochemical analytes in Sprague-Dawley rats. We established sex-specific reference intervals, including corresponding 90% confidence intervals, for Sprague-Dawley rats. CONCLUSIONS Understanding the significant discrepancies in hematologic and biochemical analytes between male and female Sprague-Dawley rats provides important insight into physiological effects in test rats. Establishment of locally sex-specific reference intervals allows a more precise evaluation of animal quality and experimental results of Sprague-Dawley rats in our toxicology safety assessment.
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Affiliation(s)
- Qili He
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
| | - Guoming Su
- Department of Pharmacy and Laboratory, Sichuan Nursing Vocational College, Chengdu, Sichuan, China
| | - Keliang Liu
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
- * E-mail:
| | - Fangcheng Zhang
- Department of Ultrastructural Pathology Center, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Yong Jiang
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
| | - Jun Gao
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
| | - Lida Liu
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
| | - Zhongren Jiang
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
| | - Minwu Jin
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
| | - Huiping Xie
- Institute of Toxicological Detection, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan, China
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Ferrannini E, Baldi S, Frascerra S, Astiarraga B, Barsotti E, Clerico A, Muscelli E. Renal Handling of Ketones in Response to Sodium-Glucose Cotransporter 2 Inhibition in Patients With Type 2 Diabetes. Diabetes Care 2017; 40:771-776. [PMID: 28325783 DOI: 10.2337/dc16-2724] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/27/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Pharmacologically induced glycosuria elicits adaptive responses in glucose homeostasis and hormone release, including decrements in plasma glucose and insulin levels, increments in glucagon release, enhanced lipolysis, and stimulation of ketogenesis, resulting in an increase in ketonemia. We aimed at assessing the renal response to these changes. RESEARCH DESIGN AND METHODS We measured fasting and postmeal urinary excretion of glucose, β-hydroxybutyrate (β-HB), lactate, and sodium in 66 previously reported patients with type 2 diabetes and preserved renal function (estimated glomerular filtration rate ≥60 mL · min-1 · 1.73 m-2) and in control subjects without diabetes at baseline and following empagliflozin treatment. RESULTS With chronic (4 weeks) sodium-glucose cotransporter 2 inhibition, baseline fractional glucose excretion (<2%) rose to 38 ± 12% and 46 ± 11% (fasting vs. postmeal, respectively; P < 0.0001) over a range of BMIs (range 23-41 kg/m2) and creatinine clearance (65-168 mL · min-1 · m-2). Excretion of β-HB (median [interquartile range]: 0.08 [0.10] to 0.31 [0.43] µmol · min-1), lactate (0.06 [0.06] to 0.28 [0.25] µmol · min-1), and sodium (0.27 [0.22] to 0.36 [0.16] mEq · min-1) all increased (P ≤ 0.001 for all) and were each positively related to glycosuria (P ≤ 0.001). These parameters changed in the same direction in subjects without diabetes, but changes were smaller than in the patients with diabetes. Although plasma N-terminal pro-B-type natriuretic peptide levels were unaltered, plasma erythropoietin concentrations increased by 31 (64)% (P = 0.0078). CONCLUSIONS We conclude that the sodium-glucose cotransporter 2 inhibitor-induced increase in β-HB is not because of reduced renal clearance but because of overproduction. The increased lactate excretion contributes to lower plasma lactate levels, whereas the increased natriuresis may help in normalizing the exchangeable sodium pool. Taken together, glucose loss through joint inhibition of glucose and sodium reabsorption in the proximal tubule induces multiple changes in renal metabolism.
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Affiliation(s)
| | - Simona Baldi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Silvia Frascerra
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Brenno Astiarraga
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Elisabetta Barsotti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Aldo Clerico
- CNR Institute of Clinical Physiology, Pisa, Italy
| | - Elza Muscelli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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Tewes S, Gueler F, Chen R, Gutberlet M, Jang MS, Meier M, Mengel M, Hartung D, Wacker F, Rong S, Hueper K. Functional MRI for characterization of renal perfusion impairment and edema formation due to acute kidney injury in different mouse strains. PLoS One 2017; 12:e0173248. [PMID: 28319118 PMCID: PMC5358739 DOI: 10.1371/journal.pone.0173248] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/17/2017] [Indexed: 12/18/2022] Open
Abstract
Purpose The purpose was to characterize acute kidney injury (AKI) in C57BL/6 (B6)- and 129/Sv (Sv)-mice by noninvasive measurement of renal perfusion and tissue edema using functional MRI. Methods Different severities of AKI were induced in B6- and Sv-mice by renal ischemia reperfusion injury (IRI). Unilateral clamping of the renal pedicle for 35 min (moderate AKI) or 45 min (severe AKI) was done. MRI (7-Tesla) was performed 1, 7 and 28 days after surgery using a flow alternating inversion recovery (FAIR) arterial spin labeling (ASL) sequence. Maps of perfusion and T1-relaxation time were calculated. Relative MRI-parameters of the IRI kidney compared to the contralateral not-clipped kidney were compared between AKI severities and between mouse strains using unpaired t-tests. In addition, fibrosis was assessed by Masson Trichrome and collagen IV staining. Results After moderate AKI relative perfusion impairment was significantly higher in B6- than in Sv-mice at d7 (55±7% vs. 82±8%, p<0.05) and d28 (76±7% vs. 102±3%, p<0.01). T1-values increased in the early phase after AKI in both mouse strains. T1-increase was more severe after prolonged ischemia times of 45 min compared to 35 min in both mouse strains, measured in the renal cortex and outer stripe of outer medulla. Kidney volume loss (compared to the contralateral kidney) occurred already after 7 days but proceeded markedly towards 4 weeks in severe AKI. Early renal perfusion impairment was predictive for later kidney volume loss. The progression to chronic kidney disease (CKD) in the severe AKI model was similar in both mouse strains as revealed by histology. Conclusion Quantification of renal perfusion and tissue edema by functional MRI allows characterization of strain differences upon AKI. Renal perfusion impairment was stronger in B6- compared to Sv-animals following moderate AKI. Prolonged ischemia times were associated with more severe perfusion impairment and edema formation in the early phase and progression to CKD within 4 weeks of observation.
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Affiliation(s)
- Susanne Tewes
- Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
- * E-mail:
| | - Faikah Gueler
- Nephrology, Hannover Medical School, Hannover, Germany
| | - Rongjun Chen
- Nephrology, Hannover Medical School, Hannover, Germany
| | - Marcel Gutberlet
- Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Mi-Sun Jang
- Nephrology, Hannover Medical School, Hannover, Germany
| | - Martin Meier
- Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Michael Mengel
- Department of Laboratory Medicine & Pathology, University of Alberta, Edmonton, Canada
| | - Dagmar Hartung
- Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Frank Wacker
- Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Song Rong
- Nephrology, Hannover Medical School, Hannover, Germany
- The Transplantation Center of the affiliated hospital, Zunyi Medical College, Zunyi, China
| | - Katja Hueper
- Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
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Jiang T, Li Y, Layton AT, Wang W, Sun Y, Li M, Zhou H, Yang B. Generation and phenotypic analysis of mice lacking all urea transporters. Kidney Int 2017; 91:338-351. [PMID: 27914708 PMCID: PMC5423716 DOI: 10.1016/j.kint.2016.09.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 08/30/2016] [Accepted: 09/08/2016] [Indexed: 01/22/2023]
Abstract
Urea transporters (UT) are a family of transmembrane urea-selective channel proteins expressed in multiple tissues and play an important role in the urine concentrating mechanism of the mammalian kidney. UT inhibitors have diuretic activity and could be developed as novel diuretics. To determine if functional deficiency of all UTs in all tissues causes physiological abnormality, we established a novel mouse model in which all UTs were knocked out by deleting an 87 kb of DNA fragment containing most parts of Slc14a1 and Slc14a2 genes. Western blot analysis and immunofluorescence confirmed that there is no expression of urea transporter in these all-UT-knockout mice. Daily urine output was nearly 3.5-fold higher, with significantly lower urine osmolality in all-UT-knockout mice than that in wild-type mice. All-UT-knockout mice were not able to increase urinary urea concentration and osmolality after water deprivation, acute urea loading, or high protein intake. A computational model that simulated UT-knockout mouse models identified the individual contribution of each UT in urine concentrating mechanism. Knocking out all UTs also decreased the blood pressure and promoted the maturation of the male reproductive system. Thus, functional deficiency of all UTs caused a urea-selective urine-concentrating defect with little physiological abnormality in extrarenal organs.
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Affiliation(s)
- Tao Jiang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yingjie Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Anita T Layton
- Department of Mathematics, Duke University, Durham, North Carolina, USA
| | - Weiling Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Min Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Hong Zhou
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Baoxue Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Beijing, China.
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Bankir L, Bouby N, Blondeau B, Crambert G. Glucagon actions on the kidney revisited: possible role in potassium homeostasis. Am J Physiol Renal Physiol 2016; 311:F469-86. [DOI: 10.1152/ajprenal.00560.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/31/2016] [Indexed: 12/25/2022] Open
Abstract
It is now recognized that the metabolic disorders observed in diabetes are not, or not only due to the lack of insulin or insulin resistance, but also to elevated glucagon secretion. Accordingly, selective glucagon receptor antagonists are now proposed as a novel strategy for the treatment of diabetes. However, besides its metabolic actions, glucagon also influences kidney function. The glucagon receptor is expressed in the thick ascending limb, distal tubule, and collecting duct, and glucagon regulates the transepithelial transport of several solutes in these nephron segments. Moreover, it also influences solute transport in the proximal tubule, possibly by an indirect mechanism. This review summarizes the knowledge accumulated over the last 30 years about the influence of glucagon on the renal handling of electrolytes and urea. It also describes a possible novel role of glucagon in the short-term regulation of potassium homeostasis. Several original findings suggest that pancreatic α-cells may express a “potassium sensor” sensitive to changes in plasma K concentration and could respond by adapting glucagon secretion that, in turn, would regulate urinary K excretion. By their combined actions, glucagon and insulin, working in a combinatory mode, could ensure an independent regulation of both plasma glucose and plasma K concentrations. The results and hypotheses reviewed here suggest that the use of glucagon receptor antagonists for the treatment of diabetes should take into account their potential consequences on electrolyte handling by the kidney.
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Affiliation(s)
- Lise Bankir
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Pierre et Marie Curie, Paris, France; and
| | - Nadine Bouby
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Pierre et Marie Curie, Paris, France; and
- Université Paris-Descartes, Paris, France
| | - Bertrand Blondeau
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Pierre et Marie Curie, Paris, France; and
| | - Gilles Crambert
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Pierre et Marie Curie, Paris, France; and
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28
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Reed GD, von Morze C, Verkman AS, Koelsch BL, Chaumeil MM, Lustig M, Ronen SM, Bok RA, Sands JM, Larson PEZ, Wang ZJ, Larsen JHA, Kurhanewicz J, Vigneron DB. Imaging Renal Urea Handling in Rats at Millimeter Resolution using Hyperpolarized Magnetic Resonance Relaxometry. ACTA ACUST UNITED AC 2016; 2:125-135. [PMID: 27570835 PMCID: PMC4996281 DOI: 10.18383/j.tom.2016.00127] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In vivo spin spin relaxation time (T2) heterogeneity of hyperpolarized [13C,15N2]urea in the rat kidney was investigated. Selective quenching of the vascular hyperpolarized 13C signal with a macromolecular relaxation agent revealed that a long-T2 component of the [13C,15N2]urea signal originated from the renal extravascular space, thus allowing the vascular and renal filtrate contrast agent pools of the [13C,15N2]urea to be distinguished via multi-exponential analysis. The T2 response to induced diuresis and antidiuresis was performed with two imaging agents: hyperpolarized [13C,15N2]urea and a control agent hyperpolarized bis-1,1-(hydroxymethyl)-1-13C-cyclopropane-2H8. Large T2 increases in the inner-medullar and papilla were observed with the former agent and not the latter during antidiuresis. Therefore, [13C,15N2]urea relaxometry is sensitive to two steps of the renal urea handling process: glomerular filtration and the inner-medullary urea transporter (UT)-A1 and UT-A3 mediated urea concentrating process. Simple motion correction and subspace denoising algorithms are presented to aid in the multi exponential data analysis. Furthermore, a T2-edited, ultra long echo time sequence was developed for sub-2 mm3 resolution 3D encoding of urea by exploiting relaxation differences in the vascular and filtrate pools.
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Affiliation(s)
- Galen D Reed
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA; Graduate Group in Bioengineering University of California San Francisco, San Francisco, California, USA, and University of California Berkeley, Berkeley, California, USA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, California, USA
| | - Bertram L Koelsch
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA; Graduate Group in Bioengineering University of California San Francisco, San Francisco, California, USA, and University of California Berkeley, Berkeley, California, USA
| | - Myriam M Chaumeil
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Michael Lustig
- Graduate Group in Bioengineering University of California San Francisco, San Francisco, California, USA, and University of California Berkeley, Berkeley, California, USA; Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California, USA
| | - Sabrina M Ronen
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA; Graduate Group in Bioengineering University of California San Francisco, San Francisco, California, USA, and University of California Berkeley, Berkeley, California, USA
| | - Robert A Bok
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Jeff M Sands
- Department of Medicine, Renal Division, Emory University, Atlanta, Georgia, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA; Graduate Group in Bioengineering University of California San Francisco, San Francisco, California, USA, and University of California Berkeley, Berkeley, California, USA
| | - Zhen J Wang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Jan Henrik Ardenkjær Larsen
- GE Healthcare, Brøndby, Denmark; Department of Electrical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA; Graduate Group in Bioengineering University of California San Francisco, San Francisco, California, USA, and University of California Berkeley, Berkeley, California, USA
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA; Graduate Group in Bioengineering University of California San Francisco, San Francisco, California, USA, and University of California Berkeley, Berkeley, California, USA
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Early administration of tolvaptan preserves renal function in elderly patients with acute decompensated heart failure. J Cardiol 2016; 67:399-405. [DOI: 10.1016/j.jjcc.2015.09.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/10/2015] [Accepted: 09/25/2015] [Indexed: 11/23/2022]
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Shimizu K, Doi K, Imamura T, Noiri E, Yahagi N, Nangaku M, Kinugawa K. Ratio of urine and blood urea nitrogen concentration predicts the response of tolvaptan in congestive heart failure. Nephrology (Carlton) 2016; 20:405-12. [PMID: 25619790 DOI: 10.1111/nep.12406] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2015] [Indexed: 11/30/2022]
Abstract
AIM This study was conducted to evaluate the performance of the ratio of urine and blood urea nitrogen concentration (UUN/BUN) as a new predictive factor for the response of an arginine vasopressin receptor 2 antagonist tolvaptan (TLV) in decompensated heart failure patients. METHODS This study enrolled 70 decompensated heart failure patients who were administered TLV at University of Tokyo Hospital. We collected the data of clinical parameters including UUN/BUN before administering TLV. Two different outcomes were defined as follows: having over 300 mL increase in urine volume on the first day (immediate urine output response) and having any decrease in body weight within one week after starting TLV treatment (subsequent clinical response). RESULTS Among the 70 enrolled patients, 37 patients (52.9%) showed immediate urine output response; 51 patients (72.9%) showed a subsequent clinical response of body weight decrease. Receiver operating characteristics (ROC) analysis showed good prediction by UUN/BUN for the immediate response (AUC-ROC 0.86 [0.75-0.93]) and a significantly better prediction by UUN/BUN for the subsequent clinical response compared with urinary osmolality (AUC-ROC 0.78 [0.63-0.88] vs. 0.68 [0.52-0.80], P < 0.05). CONCLUSIONS We demonstrated that a clinical parameter of UUN/BUN can predict the response of TLV even when measured before TLV administration. UUN/BUN might enable identification of good responders for this new drug.
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Affiliation(s)
- Keisuke Shimizu
- Clinical Research Training Program, The University of Tokyo, Tokyo, Japan
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Rafat C, Flamant M, Gaudry S, Vidal-Petiot E, Ricard JD, Dreyfuss D. Hyponatremia in the intensive care unit: How to avoid a Zugzwang situation? Ann Intensive Care 2015; 5:39. [PMID: 26553121 PMCID: PMC4639545 DOI: 10.1186/s13613-015-0066-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 09/02/2015] [Indexed: 12/11/2022] Open
Abstract
Hyponatremia is a common
electrolyte derangement in the setting of the intensive care unit. Life-threatening neurological complications may arise not only in case of a severe (<120 mmol/L) and acute fall of plasma sodium levels, but may also stem from overly rapid correction of hyponatremia. Additionally, even mild hyponatremia carries a poor short-term and long-term prognosis across a wide range of conditions. Its multifaceted and intricate physiopathology may seem deterring at first glance, yet a careful multi-step diagnostic approach may easily unravel the underlying mechanisms and enable physicians to adopt the adequate measures at the patient’s bedside. Unless hyponatremia is associated with obvious extracellular fluid volume increase such as in heart failure or cirrhosis, hypertonic saline therapy is the cornerstone of the therapeutic of profound or severely symptomatic hyponatremia. When overcorrection of hyponatremia occurs, recent data indicate that re-lowering of plasma sodium levels through the infusion of hypotonic fluids and the cautious use of desmopressin acetate represent a reasonable strategy. New therapeutic options have recently emerged, foremost among these being vaptans, but their use in the setting of the intensive care unit remains to be clarified.
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Affiliation(s)
- Cédric Rafat
- AP-HP, Service de Réanimation Médico-Chirurgicale, Hôpital Louis Mourier, Colombes, France. .,AP-HP, Urgences Néphrologiques et Transplantation Rénale, Hôpital Tenon, Paris, France.
| | - Martin Flamant
- AP-HP, Service de Physiologie Rénale, Hôpital Bichat, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, Paris, France. .,INSERM, U1149, Centre de Recherche sur l'Inflammation, Paris, France.
| | - Stéphane Gaudry
- AP-HP, Service de Réanimation Médico-Chirurgicale, Hôpital Louis Mourier, Colombes, France. .,Université Paris Diderot, Sorbonne Paris Cité, Paris, France. .,ECEVE UMR 1123, ECEVE, Paris, France.
| | - Emmanuelle Vidal-Petiot
- AP-HP, Service de Physiologie Rénale, Hôpital Bichat, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, Paris, France. .,INSERM, U1149, Centre de Recherche sur l'Inflammation, Paris, France.
| | - Jean-Damien Ricard
- AP-HP, Service de Réanimation Médico-Chirurgicale, Hôpital Louis Mourier, Colombes, France. .,Université Paris Diderot, Sorbonne Paris Cité, Paris, France. .,INSERM UMR 1137, IAME, Paris, France.
| | - Didier Dreyfuss
- AP-HP, Service de Réanimation Médico-Chirurgicale, Hôpital Louis Mourier, Colombes, France. .,Université Paris Diderot, Sorbonne Paris Cité, Paris, France. .,INSERM UMR 1137, IAME, Paris, France.
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33
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Varela CF, Greloni G, Schreck C, Bratti G, Medina A, Marenchino R, Pizarro R, Belziti C, Rosa-Diez G. Assessment of fractional excretion of urea for early diagnosis of cardiac surgery associated acute kidney injury. Ren Fail 2015; 37:327-31. [PMID: 26398357 DOI: 10.3109/0886022x.2015.1087800] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Acute kidney injury (AKI) is a common complication after cardiac surgery (CS). Recently, neutrophil gelatinase-associated lipocalin (NGAL) was shown to predict AKI development earlier than serum creatinine, but it is not widely used in clinical practice. Fractional excretion of urea (FeU) has been referred to as a useful tool to discriminate between prerenal and established AKI. The aim of our study is to evaluate the sensitivity and specificity of FeU, in the early diagnosis of AKI in patients undergoing CS. METHODS We performed a prospective study on adults undergoing CS. AKI was defined by AKIN criteria. Individuals suffering from CKD, were excluded. Sensitivity and specificity of FeU, fractional excretion of sodium (FeNa) and urine NGAL, measured at 1, 6 and 24 h following CS, were assessed. RESULTS We included 66 patients (26% female) aging 68 ± 11 years. AKI prevalence was 24% and mortality was 3.28%. Patients with AKI had a significantly lower FeU compared to those without AKI (23.89 ± 0.67% vs. 34.22 ± 0.58%; p < 0.05) 6 h after CS, but not at the 1- and 24-h time points. NGAL was also statistically significant between both groups. FeU showed a 75% sensitivity and 79.5% specificity; the AUC was 0.786. ROC analysis of FeU and NGAL yielded similar values (p = NS). CONCLUSION FeU is useful as an early biomarker to predict AKI after CS and it is comparable to the new biomarker NGAL.
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Affiliation(s)
- Carlos Federico Varela
- a Servicio de Nefrología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Gustavo Greloni
- a Servicio de Nefrología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Carlos Schreck
- a Servicio de Nefrología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Griselda Bratti
- a Servicio de Nefrología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Angel Medina
- a Servicio de Nefrología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Ricardo Marenchino
- b Servicio de Cirugía Cardiovascular del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina , and
| | - Rodolfo Pizarro
- c Servicio de Cardiología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Cesar Belziti
- c Servicio de Cardiología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Guillermo Rosa-Diez
- a Servicio de Nefrología del Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
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34
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Bankir L, Roussel R, Bouby N. Protein- and diabetes-induced glomerular hyperfiltration: role of glucagon, vasopressin, and urea. Am J Physiol Renal Physiol 2015; 309:F2-23. [DOI: 10.1152/ajprenal.00614.2014] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 04/13/2015] [Indexed: 12/21/2022] Open
Abstract
A single protein-rich meal (or an infusion of amino acids) is known to increase the glomerular filtration rate (GFR) for a few hours, a phenomenon known as “hyperfiltration.” It is important to understand the factors that initiate this upregulation because it becomes maladaptive in the long term. Several mediators and paracrine factors have been shown to participate in this upregulation, but they are not directly triggered by protein intake. Here, we explain how a rise in glucagon and in vasopressin secretion, directly induced by protein ingestion, might be the initial factors triggering the hepatic and renal events leading to an increase in the GFR. Their effects include metabolic actions in the liver and stimulation of sodium chloride reabsorption in the thick ascending limb. Glucagon is not only a glucoregulatory hormone. It is also important for the excretion of nitrogen end products by stimulating both urea synthesis in the liver (along with gluconeogenesis from amino acids) and urea excretion by the kidney. Vasopressin allows the concentration of nitrogenous end products (urea, ammonia, etc.) and other protein-associated wastes in a hyperosmotic urine, thus allowing a very significant water economy characteristic of all terrestrial mammals. No hyperfiltration occurs in the absence of one or the other hormone. Experimental results suggest that the combined actions of these two hormones, along with the complex intrarenal handling of urea, lead to alter the composition of the tubular fluid at the macula densa and to reduce the intensity of the signal activating the tubuloglomerular feedback control of GFR, thus allowing GFR to raise. Altogether, glucagon, vasopressin, and urea contribute to set up the best compromise between efficient urea excretion and water economy.
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Affiliation(s)
- Lise Bankir
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France; and
| | - Ronan Roussel
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France; and
- Diabétologie Endocrinologie Nutrition, DHU FIRE, Hôpital Bichat, AP-HP, Paris, France
| | - Nadine Bouby
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France; and
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35
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Abstract
Urea is generated by the urea cycle enzymes, which are mainly in the liver but are also ubiquitously expressed at low levels in other tissues. The metabolic process is altered in several conditions such as by diets, hormones, and diseases. Urea is then eliminated through fluids, especially urine. Blood urea nitrogen (BUN) has been utilized to evaluate renal function for decades. New roles for urea in the urinary system, circulation system, respiratory system, digestive system, nervous system, etc., were reported lately, which suggests clinical significance of urea.
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36
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Greenberg JH, Tufro A, Marsenic O. Approach to the Treatment of the Infant With Hyponatremia. Am J Kidney Dis 2015; 65:513-7. [DOI: 10.1053/j.ajkd.2014.10.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 10/02/2014] [Indexed: 11/11/2022]
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37
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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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Li M, Tou WI, Zhou H, Li F, Ren H, Chen CYC, Yang B. Developing hypothetical inhibition mechanism of novel urea transporter B inhibitor. Sci Rep 2014; 4:5775. [PMID: 25047372 PMCID: PMC5376056 DOI: 10.1038/srep05775] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/27/2014] [Indexed: 02/03/2023] Open
Abstract
Urea transporter B (UT-B) is a membrane channel protein that specifically transports urea. UT-B null mouse exhibited urea selective urine concentrating ability deficiency, which suggests the potential clinical applications of the UT-B inhibitors as novel diuretics. Primary high-throughput virtual screening (HTVS) of 50000 small-molecular drug-like compounds identified 2319 hit compounds. These 2319 compounds were screened by high-throughput screening using an erythrocyte osmotic lysis assay. Based on the pharmacological data, putative UT-B binding sites were identified by structure-based drug design and validated by ligand-based and QSAR model. Additionally, UT-B structural and functional characteristics under inhibitors treated and untreated conditions were simulated by molecular dynamics (MD). As the result, we identified four classes of compounds with UT-B inhibitory activity and predicted a human UT-B model, based on which computative binding sites were identified and validated. A novel potential mechanism of UT-B inhibitory activity was discovered by comparing UT-B from different species. Results suggest residue PHE198 in rat and mouse UT-B might block the inhibitor migration pathway. Inhibitory mechanisms of UT-B inhibitors and the functions of key residues in UT-B were proposed. The binding site analysis provides a structural basis for lead identification and optimization of UT-B inhibitors.
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Affiliation(s)
- Min Li
- The State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
- These authors contributed equally to this work
| | - Weng Ieong Tou
- School of Medicine, College of Medicine, China Medical University, Taichung, 40402, Taiwan
- These authors contributed equally to this work
| | - Hong Zhou
- The State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Fei Li
- The State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
- School of Pharmaceutical Sciences, Hubei University of Medicine, Shiyan, 442000, China
| | - Huiwen Ren
- The State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
| | - Calvin Yu-Chian Chen
- School of Medicine, College of Medicine, China Medical University, Taichung, 40402, Taiwan
- Human Genetic Center, Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
- Department of Biomedical Informatics, Asia University, Taichung, 41354, Taiwan
- Research Center for Chinese Medicine & Acupuncture, China Medical University, Taichung 40402, Taiwan
| | - Baoxue Yang
- The State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
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Rosendale AJ, Philip BN, Lee RE, Costanzo JP. Cloning, characterization, and expression of glucose transporter 2 in the freeze-tolerant wood frog, Rana sylvatica. Biochim Biophys Acta Gen Subj 2014; 1840:1701-11. [DOI: 10.1016/j.bbagen.2013.12.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 12/01/2013] [Accepted: 12/09/2013] [Indexed: 01/22/2023]
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Abstract
Some unicellular organisms can take up urea from the surrounding fluids by an uphill pumping mechanism. Several active (energy-dependent) urea transporters (AUTs) have been cloned in these organisms. Functional studies show that active urea transport also occurs in elasmobranchs, amphibians, and mammals. In the two former groups, active urea transport may serve to conserve urea in body fluids in order to balance external high ambient osmolarity or prevent desiccation. In mammals, active urea transport may be associated with the need to either store and/or reuse nitrogen in the case of low nitrogen supply, or to excrete nitrogen efficiently in the case of excess nitrogen intake. There are probably two different families of AUTs, one with a high capacity able to establish only a relatively modest transepithelial concentration difference (renal tubule of some frogs, pars recta of the mammalian kidney, early inner medullary collecting duct in some mammals eating protein-poor diets) and others with a low capacity but able to maintain a high transepithelial concentration difference that has been created by another mechanism or in another organ (elasmobranch gills, ventral skin of some toads, and maybe mammalian urinary bladder). Functional characterization of these transporters shows that some are coupled to sodium (symports or antiports) while others are sodium-independent. In humans, only one genetic anomaly, with a mild phenotype (familial azotemia), is suspected to concern one of these transporters. In spite of abundant functional evidence for such transporters in higher organisms, none have been molecularly identified yet.
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Affiliation(s)
- Lise Bankir
- INSERM UMRS 1138, Centre de Recherche Des Cordeliers, Paris, France,
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41
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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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42
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Ren H, Gu L, Andreasen A, Thomsen JS, Cao L, Christensen EI, Zhai XY. Spatial organization of the vascular bundle and the interbundle region: three-dimensional reconstruction at the inner stripe of the outer medulla in the mouse kidney. Am J Physiol Renal Physiol 2013; 306:F321-6. [PMID: 24305474 DOI: 10.1152/ajprenal.00429.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vascular bundle (VB) is a complex structure that resides in the inner stripe of the outer medulla. At present, the tubulovascular spatial organization of the VB, which is crucial for the formation of the osmolarity gradient and for solute transport, is still under debate. In this study, we used computer-assisted digital tracing combined with aquaporin-1 immunohistochemistry to reconstruct all tubules and vessels in the VB of the mouse kidney. We found, first, that the descending and ascending vasa recta travelled exclusively through the VB. The ascending vasa recta received no tributaries (no branches) along their entire path in the medulla and were not connected with the capillary plexus in the interbundle region. Second, a specific group of the descending vasa recta were closely accompanied by the longest ascending vasa recta, which connected only to the capillary plexus at the tip of the papilla. Third, the descending thin limbs of all short-looped nephrons travelled exclusively through the outer part of the VB. The loops of these nephrons (both descending and ascending parts) were distributed in a regular pattern based on their length. Finally, the thick ascending limbs of all long-looped nephrons were located at the margin of the VB (except a few within the VB), which formed a layer separating the VB from the interbundle region. In conclusion, our three-dimensional analysis of the VB strongly suggest a lateral osmolarity heterogeneity across the inner stripe of the outer medulla, which might work as a driving force for water and solute transport.
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Affiliation(s)
- Hao Ren
- Dept. of Histology and Embryology, China Medical Univ., No. 92, Beier Road, Heping District, Shenyang 110001, China.
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43
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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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44
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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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45
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Layton AT, Bankir L. Impacts of Active Urea Secretion into Pars Recta on Urine Concentration and Urea Excretion Rate. Physiol Rep 2013; 1. [PMID: 24058732 PMCID: PMC3777697 DOI: 10.1002/phy2.34] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
It has been observed experimentally that early distal tubular urea flow exceeds urea delivery by the proximal convoluted tubule to the pars recta and loop of Henle. Moreover, the fractional excretion of urea in the urine may exceed values compatible with the reabsorption known to occur in the proximal convoluted tubule in the cortex. A likely explanation for these observations is that urea may be actively secreted into the pars recta, as proposed in a few studies. However, this hypothesis has yet to be demonstrated experimentally. In this study, we used a mathematical model of the renal medulla of the rat kidney to investigate the impacts of active urea secretion in the intrarenal handling of urea and in the urine concentrating ability. The model represents only the outer and inner medullary zones, with the actions taking place in the cortex incorporated via boundary conditions. Blood flow in the model vasculature is divided into plasma and red blood cell compartments. We compared urea flow rates and other related model variables without and with the hypothetical active urea secretion in the pars recta. The simulation suggests that active urea secretion induces a “urea-selective” improvement in urine concentrating ability by enhancing the efficiency of urea excretion without requiring a higher urine flow rate, and with only modest changes in the excretion of other solutes. These results should encourage experimental studies in order to assess the existence of an active urea secretion in the rodent kidney.
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Affiliation(s)
- Anita T Layton
- Department of Mathematics, Duke University, Durham, NC 27708-0320, USA
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46
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Liu Y, Esteva-Font C, Yao C, Phuan PW, Verkman AS, Anderson MO. 1,1-Difluoroethyl-substituted triazolothienopyrimidines as inhibitors of a human urea transport protein (UT-B): new analogs and binding model. Bioorg Med Chem Lett 2013; 23:3338-41. [PMID: 23597791 PMCID: PMC3954708 DOI: 10.1016/j.bmcl.2013.03.089] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 03/21/2013] [Accepted: 03/22/2013] [Indexed: 11/28/2022]
Abstract
The kidney urea transport protein UT-B is an attractive target for the development of small-molecule inhibitors with a novel diuretic ('urearetic') action. Previously, two compounds in the triazolothienopyrimidine scaffold (1a and 1c) were reported as UT-B inhibitors. Compound 1c incorporates a 1,1-difluoroethyl group, which affords improved microsomal stability when compared to the corresponding ethyl-substituted compound 1a. Here, a small focused library (4a-4f) was developed around lead inhibitor 1c to investigate the requirement of an amidine-linked thiophene in the inhibitor scaffold. Two compounds (4a and 4b) with nanomolar inhibitory potency (IC50≈40 nM) were synthesized. Computational docking of lead structure 1c and 4a-4f into a homology model of the UT-B cytoplasmic surface suggested binding with the core heterocycle buried deep into the hydrophobic pore region of the protein.
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Affiliation(s)
- Y. Liu
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132-4236, United States
| | - C. Esteva-Font
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, United States
| | - C. Yao
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, United States
| | - P. W. Phuan
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, United States
| | - A. S. Verkman
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, United States
| | - M. O. Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132-4236, United States
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Sontrop JM, Dixon SN, Garg AX, Buendia-Jimenez I, Dohein O, Huang SHS, Clark WF. Association between water intake, chronic kidney disease, and cardiovascular disease: a cross-sectional analysis of NHANES data. Am J Nephrol 2013; 37:434-42. [PMID: 23594828 DOI: 10.1159/000350377] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/28/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Evidence from animal and human studies suggests a protective effect of higher water intake on kidney function and cardiovascular disease (CVD). Here the associations between water intake, chronic kidney disease (CKD) and CVD were examined in the general population. METHODS We conducted a cross-sectional analysis of the 2005-2006 National Health and Nutrition Examination Survey. Non-pregnant adults with an estimated glomerular filtration rate (eGFR) ≥30 ml/min/1.73 m(2) who were not taking diuretics were included. Total water intake from foods and beverages was categorized as low (<2.0 l/day), moderate (2.0-4.3 l/day) and high (>4.3 l/day). We examined associations between low total water intake and CKD (eGFR 30-60 ml/min/1.73 m(2)) and self-reported CVD. RESULTS Of 3,427 adults (mean age 46 (range 20-84); mean eGFR 95 ml/min/1.73 m(2) (range 30-161)), 13% had CKD and 18% had CVD. CKD was higher among those with the lowest (<2.0 l/day) vs. highest total water intake (>4.3 l/day) (adjusted odds ratio (OR) 2.52; 95% confidence interval (CI) 0.91-6.96). When stratified by intake of (1) plain water and (2) other beverages, CKD was associated with low intake of plain water: adjusted OR 2.36 (95% CI 1.10-5.06), but not other beverages: adjusted OR 0.87 (95% CI 0.30-2.50). There was no association between low water intake and CVD (adjusted OR 0.76; 95% CI 0.37-1.59). CONCLUSIONS Our results provide additional evidence suggesting a potentially protective effect of higher total water intake, particularly plain water, on the kidney.
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Affiliation(s)
- Jessica M Sontrop
- Department of Medicine, Kidney Clinical Research Unit, Division of Nephrology, London Health Sciences Centre, London, Ont., Canada
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Pannabecker TL. Comparative physiology and architecture associated with the mammalian urine concentrating mechanism: role of inner medullary water and urea transport pathways in the rodent medulla. Am J Physiol Regul Integr Comp Physiol 2013; 304:R488-503. [PMID: 23364530 PMCID: PMC3627947 DOI: 10.1152/ajpregu.00456.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 01/25/2013] [Indexed: 01/07/2023]
Abstract
Comparative studies of renal structure and function have potential to provide insights into the urine-concentrating mechanism of the mammalian kidney. This review focuses on the tubular transport pathways for water and urea that play key roles in fluid and solute movements between various compartments of the rodent renal inner medulla. Information on aquaporin water channel and urea transporter expression has increased our understanding of functional segmentation of medullary thin limbs of Henle's loops, collecting ducts, and vasa recta. A more complete understanding of membrane transporters and medullary architecture has identified new and potentially significant interactions between these structures and the interstitium. These interactions are now being introduced into our concept of how the inner medullary urine-concentrating mechanism works. A variety of regulatory pathways lead directly or indirectly to variable patterns of fluid and solute movements among the interstitial and tissue compartments. Animals with the ability to produce highly concentrated urine, such as desert species, are considered to exemplify tubular structure and function that optimize urine concentration. These species may provide unique insights into the urine-concentrating process.(1)
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Affiliation(s)
- Thomas L Pannabecker
- Department of Physiology, AHSC 4128, University of Arizona Health Sciences Center, 1501 N. Campbell Ave., Tucson, AZ 85724-5051, USA.
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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: 136] [Impact Index Per Article: 12.4] [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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Bankir L, Yang B. The Authors Reply. Kidney Int 2012. [DOI: 10.1038/ki.2012.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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