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Aggrey SE, Ghareeb AFA, Milfort MC, Ariyo OW, Aryal B, Hartono E, Kwakye J, Sovi S, Hipple SA, Stevenson C, Fuller AL, El Sabry MI, Stino F, Rekaya R. Quantitative and molecular aspects of water intake in meat-type chickens. Poult Sci 2023; 102:102973. [PMID: 37633082 PMCID: PMC10474491 DOI: 10.1016/j.psj.2023.102973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/28/2023] Open
Abstract
Even though water is the most essential nutrient for poultry production, adequate data on individual water intake in broiler chickens and its relationship with other traits of economic importance is scant. Water is provided to chickens in an unrestricted manner in spite of being a finite resource. Climate change continues to affect water sources and efficient bird use of water is long overdue. Understanding the biological basis of water intake is essential for sustainability of the poultry industry. Individual water and feed intake, and growth data was collected on 520 commercial broilers aged 14 to 42 days. We introduced the concepts of water conversion ratio (WCR) and residual water intake (RWI) as parameters that can be used to assess water intake efficiency. Water conversion ratio was defined as the amount of water consumed per unit of body weight gain, and RWI was defined as the difference between the actual water intake (WI) of a given bird and the expected WI by an average bird from the population with the same metabolic body weight, feed intake (FI) and body weight gain (BWG). The correlation between WI and FI was positive (r=0.77; P<0.0001), and the correlation between WI and BWG was positive (r=0.80; P<0.0001). Based on the distribution of RWI, the bottom 5 birds (LRWI) and the top 5 birds (HRWI) for RWI were selected for mRNA expression differences. The average broiler consumed about 7.8 L (± 1L) of water from 14 to 42 days of age. The mRNA expression of arginine vasopressin (AVP) antidiuretic hormone, calcium sensing receptor (CasR), sodium channel epithelial 1 subunit alpha (SCNN1A) and SCNN1D in the hypothalamus was upregulated in the LRWI group compared to the HRWI group. Similarly, kidney aquaporins (AQP) 2, 3, and 4 were upregulated in the LRWI group compared with the HRWI group. Given that water was provided ad libitum, the up-regulation of AVP and AQP gene mRNA expressions seem to indicate that the LRWI birds were more efficient in water reabsorption in the kidney compared to their HRWI counterparts. Increased water reabsorption will reduce the amount of water consumed to attain hydration. The water reabsorption potential was reflected in the excreta moisture levels as the LRWI birds had significantly lower excreta moisture than the HRWI birds. Excreta moisture level require further studies and could be considered as a potential proxy trait for water intake.
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Affiliation(s)
- Samuel E Aggrey
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602.
| | - Ahmed F A Ghareeb
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Marie C Milfort
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Oluwatomide W Ariyo
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Bikash Aryal
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Evan Hartono
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Josephine Kwakye
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Selorm Sovi
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Sommer A Hipple
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | - Carrienton Stevenson
- Department of Agricultural Engineering Technology, Fort Valley State University, Fort Valley, GA, 31030
| | - Alberta L Fuller
- Water Intake Genomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA, 30602
| | | | - Farid Stino
- Department of Animal Production, Cairo University, Giza, Egypt
| | - Romdhane Rekaya
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, 30602
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Tang H, Xu C, Zhang P, Luo T, Huang Y, Yang X. A profile of SGLT-2 inhibitors in hyponatremia: The evidence to date. Eur J Pharm Sci 2023; 184:106415. [PMID: 36870579 DOI: 10.1016/j.ejps.2023.106415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 02/14/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023]
Abstract
Hyponatremia is the most common electrolyte disorder in clinical practice, which may lead to life-threatening complications. Several lines of evidence suggest that hyponatremia is associated not only with significant increases in length of stay, cost, and financial burden, but also with increased morbidity and mortality. Hyponatremia is also considered to be a negative prognostic factor in patients with heart failure and cancer. Although multiple therapeutic methods are available for treating hyponatremia, most have some limitations, such as poor compliance, rapid correction of serum Na+, other negative side effects and high cost. Given these limitations, identifying novel therapies for hyponatremia is essential. Recent clinical studies have shown that SGLT-2 inhibitors (SGLT 2i) significantly increased serum Na+ levels and were well tolerated by patients who underwent this treatment. Therefore, oral administration of SGLT 2i appears to be an effective treatment for hyponatremia. This article will briefly review the etiology of hyponatremia and integrated control of sodium within the kidney, current therapies for hyponatremia, potential mechanisms and efficacy of SGLT 2i for hyponatremia, and the benefits in cardiovascular, cancer, and kidney disease by regulating sodium and water balance.
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Affiliation(s)
- Hui Tang
- Department of Pharmacy, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, China; School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Changjing Xu
- Department of Pharmacy, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, China
| | - Piao Zhang
- Department of Pharmacy, Ya 'an People's Hospital, Ya 'an, Sichuan 646000, China
| | - Taimin Luo
- Department of pharmacy, Chengdu Seventh People's Hospital, Chengdu, Sichuan 610000, China
| | - Yilan Huang
- Department of Pharmacy, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, China; School of Pharmacy, Southwest Medical University, Luzhou 646000, China.
| | - Xuping Yang
- Department of Pharmacy, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, China; School of Pharmacy, Southwest Medical University, Luzhou 646000, China.
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Ruan S, Lu Z, Huang W, Zhang Y, Shan X, Song W, Ji C. Renal metabolomic profiling of large yellow croaker Larimichthys crocea acclimated in low salinity waters. Comp Biochem Physiol Part D Genomics Proteomics 2023; 46:101083. [PMID: 37137257 DOI: 10.1016/j.cbd.2023.101083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 04/21/2023] [Accepted: 04/22/2023] [Indexed: 05/05/2023]
Abstract
Cultivation of Larimichthys crocea in low salinity water has been regarded as an effective way to treat diseases induced by pathogens in seawater. The kidney of euryhaline teleost plays important roles in not only osmoregulation but also regulation of intermediary metabolism. However, the renal responses of metabolism and osmoregulation in L. crocea to low salinity waters are still rarely reported. In this work, renal metabolomic analysis based on MS technique was conducted on the L. crocea following cultivation in salinities of 24, 8, 6, 4, and 2 ppt for 40 days. A total of 485 metabolites covering organic acids and derivatives (34.17 %), lipids and lipid-like molecules (17.55 %), organoheterocyclic compounds (12.22 %), nucleosides, nucleotides, and analogues (11.91 %), and organic oxygen compounds (10.97 %), were identified in L. crocea kidney. Compared with control group (salinity 24), nearly all amino acids, nucleotides, and their derivatives were decreased in the kidney of L. crocea, whereas most of lipid-related metabolites including phospholipid, glycerophospholipids, and fatty acids were increased. The decrease in urea and inorganic ions as well as TMAO, betaine and taurine in L. crocea kidney suggested the less demand for maintaining osmotic homeostasis. Several intermediary metabolites covering amino acids, TCA cycle intermediates, and fatty acids were also significantly changed to match with the shift of energy allocation from osmoregulation to other biological processes. The reduced energy demand for osmoregulation might contribute to the promotion of L. crocea growth under low salinity environment. What is more, carbamoylphosphate and urea that showed linear salinity response curves and higher ED50 values were potential biomarkers to adaptation to low salinity water. Overall, the characterization of metabolomes of L. crocea kidney under low salinity provided a better understanding of the adaptive mechanisms to low salinity water and potentially contributed to a reference for optimal culture salinity and feed formula of L. crocea culture in low salinity water.
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Affiliation(s)
- Shaojiang Ruan
- The Engineering Technology Research Center of Characteristic Medicinal Plants of Fujian, College of Life Sciences, Ningde Normal University, Ningde 352100, PR China
| | - Zhen Lu
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai 264003, PR China
| | - Weiqing Huang
- The Engineering Technology Research Center of Characteristic Medicinal Plants of Fujian, College of Life Sciences, Ningde Normal University, Ningde 352100, PR China; Ningde Dingcheng Fisheries Co., Ltd. in Fujian, Ningde 352100, PR China.
| | - Yi Zhang
- Mindong Fishery Research Institute of Fujian Province, Ningde 352100, PR China; Ningde Dingcheng Fisheries Co., Ltd. in Fujian, Ningde 352100, PR China
| | - Xiujuan Shan
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China
| | - Wei Song
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, PR China
| | - Chenglong Ji
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai 264003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China.
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Matsukuma Y, Nakayama M, Tsuda S, Fukui A, Yoshitomi R, Tsuruya K, Nakano T, Kitazono T. Association between the urinary sodium-to-potassium ratio and renal outcomes in patients with chronic kidney disease: a prospective cohort study. Hypertens Res 2021; 44:1492-504. [PMID: 34480132 DOI: 10.1038/s41440-021-00741-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/22/2021] [Accepted: 08/10/2021] [Indexed: 02/07/2023]
Abstract
A higher urinary sodium-to-potassium (UNa/K) ratio has been reported to be associated with high blood pressure and subsequent cardiovascular events. However, the association between the UNa/K ratio and renal outcomes remains uncertain. We prospectively investigated the association between the UNa/K ratio and renal outcomes in patients with chronic kidney disease (CKD). We enrolled 716 patients with CKD, and 24-h urinary sodium and potassium excretion were measured. Patients were divided into UNa/K ratio tertiles (T1-T3). Endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage kidney disease (ESKD), or death and a composite of doubling of SCr or ESKD (added as an alternative outcome). We investigated the association between the UNa/K ratio and renal outcomes using a Cox proportional hazards model. During a median follow-up of 2.3 years, doubling of SCr, ESKD, or death and doubling of SCr or ESKD occurred in 332 and 293 patients, respectively. After adjustment for covariates including potentially confounding variables such as plasma renin activity, plasma aldosterone concentration, and B-type natriuretic peptide, the hazard ratios (HRs) (95% confidence intervals [CIs]) for the composite of doubling of SCr, ESKD, or death for T2 and T3 were 1.44 (1.06-1.96) and 1.59 (1.14-2.21), respectively, compared with T1. Additionally, compared with T1, the highest tertile (T3) of the UNa/K ratio was associated with a composite of doubling of SCr or ESKD (HR 1.55, 95% CI 1.09-2.20). A higher UNa/K ratio was independently associated with poor renal outcomes in patients with CKD.
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Boggula VR, Hanukoglu I, Sagiv R, Enuka Y, Hanukoglu A. Expression of the epithelial sodium channel (ENaC) in the endometrium - Implications for fertility in a patient with pseudohypoaldosteronism. J Steroid Biochem Mol Biol 2018; 183:137-141. [PMID: 29885352 DOI: 10.1016/j.jsbmb.2018.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/01/2018] [Accepted: 06/05/2018] [Indexed: 01/21/2023]
Abstract
Pseudohypoaldosteronism type 1 (PHA) is a syndrome of unresponsiveness to aldosterone. The severe form of this disease results from mutations in the genes that encode for the epithelial sodium channel subunits, SCNN1A, SCNN1B, and SCNN1G. A PHA patient under our care failed to conceive after many years and IVF trials. Our earlier studies had shown that ENaC is expressed in the female reproductive tract. We hypothesized that a defective ENaC expression may be responsible for the infertility of the patient. To test this hypothesis we examined ENaC expression in endometrial Pipelle biopsy samples from three healthy women and the PHA patient with an Arg508X mutation in the SCNN1A gene. The formalin fixed samples were reacted with anti-ENaCA (alpha subunit) antisera, followed by secondary antibodies to visualize ENaC expression by immunofluorescence. Confocal microscopy imaging of the samples showed strong ENaC immunofluorescence along the luminal border (apical membrane) of the epithelial cells in Pipelle samples from healthy women. In contrast, none of the samples from the PHA patient showed ENaC immunofluorescence. The Arg508X mutation interrupts the transport of ENaC subunits to the cell surface, yet it would not be expected to disrupt ENaC localization in the cytoplasm. In contrast to endometrium where ENaC is localized in the apical membrane of the epithelial cells, in keratinocytes ENaC is expressed in cytoplasmic pools. Therefore, we examined ENaC immunofluorescence in plucked hair follicles. As expected, ENaC immunofluorescence was detected in the cytoplasm of keratinocytes of both normal and PHA samples. Our results support the hypothesis that lack of expression of ENaC on the endometrial surface may be responsible for the infertility of the PHA patient.
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Affiliation(s)
| | | | - Ron Sagiv
- Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel; Department of Obstetrics & Gynecology, E. Wolfson Medical Center, Holon, Israel
| | - Yehoshua Enuka
- Laboratory of Cell Biology, Ariel University, Ariel, Israel
| | - Aaron Hanukoglu
- Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel; Division of Pediatric Endocrinology, E. Wolfson Medical Center, Holon, Israel.
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Jędrusik P, Symonides B, Gaciong Z. Comparison of three formulas to estimate 24-hour urinary sodium and potassium excretion in patients hospitalized in a hypertension unit. ACTA ACUST UNITED AC 2018; 12:457-469. [DOI: 10.1016/j.jash.2018.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/02/2018] [Accepted: 03/20/2018] [Indexed: 10/17/2022]
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Caceres PS, Benedicto I, Lehmann GL, Rodriguez-Boulan EJ. Directional Fluid Transport across Organ-Blood Barriers: Physiology and Cell Biology. Cold Spring Harb Perspect Biol 2017; 9:a027847. [PMID: 28003183 PMCID: PMC5334253 DOI: 10.1101/cshperspect.a027847] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Directional fluid flow is an essential process for embryo development as well as for organ and organism homeostasis. Here, we review the diverse structure of various organ-blood barriers, the driving forces, transporters, and polarity mechanisms that regulate fluid transport across them, focusing on kidney-, eye-, and brain-blood barriers. We end by discussing how cross talk between barrier epithelial and endothelial cells, perivascular cells, and basement membrane signaling contribute to generate and maintain organ-blood barriers.
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Affiliation(s)
- Paulo S Caceres
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Ignacio Benedicto
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Guillermo L Lehmann
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Enrique J Rodriguez-Boulan
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
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Abstract
The renal thiazide-sensitive NaCl cotransporter, NCC, is the major pathway for salt reabsorption in the distal convoluted tubule. The activity of this cotransporter is critical for regulation of several physiological variables such as blood pressure, serum potassium, acid base metabolism, and urinary calcium excretion. Therefore, it is not surprising that numerous hormone-signaling pathways regulate NCC activity to maintain homeostasis. In this review, we will provide an overview of the most recent evidence on NCC modulation by aldosterone, angiotensin II, vasopressin, glucocorticoids, insulin, norepinephrine, estradiol, progesterone, prolactin, and parathyroid hormone.
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Affiliation(s)
- Lorena Rojas-Vega
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico; and
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico; and
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Jensen JM, Mose FH, Kulik AEO, Bech JN, Fenton RA, Pedersen EB. Changes in urinary excretion of water and sodium transporters during amiloride and bendroflumethiazide treatment. World J Nephrol 2015; 4:423-437. [PMID: 26167467 PMCID: PMC4491934 DOI: 10.5527/wjn.v4.i3.423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 03/08/2015] [Accepted: 04/30/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To quantify changes in urinary excretion of aquaporin2 water channels (u-AQP2), the sodium-potassium-chloride co-transporter (u-NKCC2) and the epithelial sodium channels (u-ENaC) during treatment with bendroflumethiazide (BFTZ), amiloride and placebo.
METHODS: In a randomized, double-blinded, placebo-controlled, 3-way crossover study we examined 23 healthy subjects on a standardized diet and fluid intake. The subjects were treated with amiloride 5 mg, BFTZ 1.25 mg or placebo twice a day for 4.5 d before each examination day. On the examination day, glomerular filtration rate was measured by the constant infusion clearance technique with 51Cr-EDTA as reference substance. To estimate the changes in water transport via AQP2 and sodium transport via NKCC2 and ENaC, u-NKCC2, the gamma fraction of ENaC (u-ENaCγ), and u-AQP2 were measured at baseline and after infusion with 3% hypertonic saline. U-NKCC2, u-ENaCγ, u-AQP2 and plasma concentrations of vasopressin (p-AVP), renin (PRC), angiotensin II (p-ANG II) and aldosterone (p-Aldo) were measured, by radioimmunoassay. Central blood pressure was estimated by applanation tonometry and body fluid volumes were estimated by bio-impedance spectroscopy. General linear model with repeated measures or related samples Friedman’s two-way analysis was used to compare differences. Post hoc Bonferroni correction was used for multiple comparisons of post infusion periods to baseline within each treatment group.
RESULTS: At baseline there were no differences in u-NKCC2, u-ENaCγ and u-AQP2. PRC, p-Ang II and p-Aldo were increased during active treatments (P < 0.001). After hypertonic saline, u-NKCC2 increased during amiloride (6% ± 34%; P = 0.081) and increased significantly during placebo (17% ± 24%; P = 0.010). U-AQP2 increased significantly during amiloride (31% ± 22%; P < 0.001) and placebo (34% ± 27%; P < 0.001), while u-NKCC2 and u-AQP2 did not change significantly during BFTZ (-7% ± 28%; P = 0.257 and 5% ± 16%; P = 0.261). U- ENaCγ increased in all three groups (P < 0.050). PRC, AngII and p-Aldo decreased to the same extent, while AVP increased, but to a smaller degree during BFTZ (P = 0.048). cDBP decreased significantly during BFTZ (P < 0.001), but not during amiloride or placebo. There were no significant differences in body fluid volumes.
CONCLUSION: After hypertonic saline, u-NKCC2 and u-AQP2 increased during amiloride, but not during BFTZ. Lower p-AVP during BFTZ potentially caused less stimulation of NKCC2 and AQP2 and subsequent lower reabsorption of water and sodium.
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Abstract
Elevated blood pressure arises from a combination of environmental and genetic factors and the interactions of these factors. A substantial body of evidence from animal studies, epidemiologic studies, meta-analyses, and randomized controlled trials has demonstrated that certain dietary patterns and individual dietary elements play a prominent role in the development of hypertension. Changes in diet can lower blood pressure, prevent the development of hypertension, and reduce the risk of hypertension-related complications. Dietary strategies for the prevention of hypertension include reducing sodium intake, limiting alcohol consumption, increasing potassium intake, and adopting an overall dietary pattern such as the DASH (Dietary Approaches to Stop Hypertension) diet or a Mediterranean diet. In order to reduce the burden of blood pressure-related complications, efforts that focus on environmental and individual behavioral changes that encourage and promote healthier food choices are warranted.
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Vitzthum H, Seniuk A, Schulte LH, Müller ML, Hetz H, Ehmke H. Functional coupling of renal K+ and Na+ handling causes high blood pressure in Na+ replete mice. J Physiol 2014; 592:1139-57. [PMID: 24396058 DOI: 10.1113/jphysiol.2013.266924] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A network of kinases, including WNKs, SPAK and Sgk1, is critical for the independent regulation of K+ and Na+ transport in the distal nephron. Angiotensin II is thought to act as a key hormone in orchestrating these kinases to switch from K+ secretion during hyperkalaemia to Na+ reabsorption during intravascular volume depletion, thus keeping disturbances in electrolyte and blood pressure homeostasis at a minimum. It remains unclear, however, how K+ and Na+ transport are regulated during a high Na+ intake, which is associated with suppressed angiotensin II levels and a high distal tubular Na+ load. We therefore investigated the integrated blood pressure, renal, hormonal and gene and protein expression responses to large changes of K+ intake in Na+ replete mice. Both low and high K+ intake increased blood pressure and caused Na+ retention. Low K+ intake was accompanied by an upregulation of the sodium-chloride cotransporter (NCC) and its activating kinase SPAK, and inhibition of NCC normalized blood pressure. Renal responses were unaffected by angiotensin AT1 receptor antagonism, indicating that low K+ intake activates the distal nephron by an angiotensin-independent mode of action. High K+ intake was associated with elevated plasma aldosterone concentrations and an upregulation of the epithelial sodium channel (ENaC) and its activating kinase Sgk1. Surprisingly, high K+ intake increased blood pressure even during ENaC or mineralocorticoid receptor antagonism, suggesting the contribution of aldosterone-independent mechanisms. These findings show that in a Na+ replete state, changes in K+ intake induce specific molecular and functional adaptations in the distal nephron that cause a functional coupling of renal K+ and Na+ handling, resulting in Na+ retention and high blood pressure when K+ intake is either restricted or excessively increased.
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Affiliation(s)
- Helga Vitzthum
- Department of Cellular and Integrative Physiology, Centre for Experimental Medicine, University Medical Centre Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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Jensen JM, Mose FH, Bech JN, Nielsen S, Pedersen EB. Effect of volume expansion with hypertonic- and isotonic saline and isotonic glucose on sodium and water transport in the principal cells in the kidney. BMC Nephrol. 2013;14:202. [PMID: 24067081 PMCID: PMC3849534 DOI: 10.1186/1471-2369-14-202] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/23/2013] [Indexed: 12/21/2022] Open
Abstract
Background The renal distal nephron plays an important role in the maintenance of sodium balance, extra cellular volume and blood pressure. The degree of water transport, via aquaporin2 water channels (AQP2), and sodium transport, via epithelial sodium channels (ENaC) in renal collecting duct principal cells are reflected by the level of urinary excretion of AQP2 (u-AQP2) and the γ-fraction of ENaC (u-ENaCγ). The effects of an acute intravenous volume load with isotonic saline, hypertonic saline and glucose on u-AQP2, u-ENaCγ and underlying mechanisms have never been studied in a randomized, placebo-controlled trial in healthy humans. Methods We studied the effects of 0.9% saline (23 ml/kg), 3% saline (7 ml/kg) and 5% glucose (23 ml/kg) on u-AQP2 and u-ENaCγ, fractional sodium excretion (FENa), free water clearance (CH2O), and plasma concentrations of vasopressin (AVP), renin (PRC), angiotensin II (ANG II) and aldosterone (Aldo) in a randomized, crossover study of 23 healthy subjects, who consumed a standardized diet, regarding calories, sodium and fluid for 4 days before each examination day. Results After isotonic saline infusion, u-AQP2 increased (27%). CH2O and u-ENaCγ were unchanged, whereas FENa increased (123%). After hypertonic saline infusion, there was an increase in u-AQP2 (25%), u-ENaCγ (19%) and FENa (96%), whereas CH2O decreased (-153%). After isotonic glucose infusion, there was a decrease in u-AQP2 (-16%), ENaCγ (-10%) and FENa (-44%) whereas CH2O increased (164%). AVP remained unchanged after isotonic saline and glucose, but increased after hypertonic saline (139%). PRC, AngII and p-Aldo decreased after isotonic and hypertonic saline infusion, but not after glucose infusion. Conclusions Volume expansion with 3% and 0.9% saline increased u-AQP2, while isotonic glucose decreased u-AQP2. Infusion of hypertonic saline increased u-ENaCγ, whereas u-ENaCγ was not significantly changed after isotonic saline and tended to decrease after glucose. Thus, the transport of water and sodium is changed both via the aquaporin 2 water channels and the epithelial sodium channels during all three types of volume expansion to regulate and maintain water- and sodium homeostasis in the body. Trial registration Clinical Trial no: NCT01414088
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Shimizu M, Goto T, Sato A, Shibuya H. WNK4 is an essential effector of anterior formation in FGF signaling. Genes Cells 2013; 18:442-9. [PMID: 23517227 PMCID: PMC3712470 DOI: 10.1111/gtc.12048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 02/17/2013] [Indexed: 11/30/2022]
Abstract
With no lysine (K) (WNK) kinase family is conserved among many species and regulates SPAK/OSR1 and ion cotransporters. WNK is also involved in developmental and cellular processes, but the molecular mechanisms underlying its regulation in these processes remain unknown. In this study, we found that WNK4 is involved in fibroblast growth factor (FGF) signaling during Xenopus development. In Xenopus embryos, depletion of WNK4 by antisense morpholino oligonucleotides (MOs) results in a severe defect in anterior development and impaired expression of endogenous anterior markers. Defects in head formation or expression of anterior marker genes caused by suppression of endogenous WNK4 expression could be rescued by expression of wild-type WNK4, but not mutant WNK4 lacking its kinase activity. It is notable that morphants of Xenopus WNK4 inhibited the expression of anterior marker genes and the target genes induced by FGF signaling. Moreover, knockdown of Wnk4 significantly reduced the phosphorylation level of Osr1 induced by FGF. These results provide the first evidence that FGF signaling regulates WNK4 function required for anterior formation in Xenopus development.
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Affiliation(s)
- Masahiro Shimizu
- Department of Molecular Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
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Sevá Pessôa B, van der Lubbe N, Verdonk K, Roks AJM, Hoorn EJ, Danser AHJ. Key developments in renin-angiotensin-aldosterone system inhibition. Nat Rev Nephrol 2012; 9:26-36. [PMID: 23165302 DOI: 10.1038/nrneph.2012.249] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The renin-angiotensin-aldosterone system (RAAS) was initially thought to be fairly simple. However, this idea has been challenged following the development of RAAS blockers, including renin inhibitors, angiotensin-converting-enzyme (ACE) inhibitors, type 1 angiotensin II (AT(1))-receptor blockers and mineralocorticoid-receptor antagonists. Consequently, new RAAS components and pathways that might contribute to the effectiveness of these drugs and/or their adverse effects have been identified. For example, an increase in renin levels during RAAS blockade might result in harmful effects via stimulation of the prorenin receptor (PRR), and prorenin-the inactive precursor of renin-might gain enzymatic activity on PRR binding. The increase in angiotensin II levels that occurs during AT(1)-receptor blockade might result in beneficial effects via stimulation of type 2 angiotensin II receptors. Moreover, angiotensin 1-7 levels increase during ACE inhibition and AT(1)-receptor blockade, resulting in Mas receptor activation and the induction of cardioprotective and renoprotective effects, including stimulation of tissue repair by stem cells. Finally, a role of angiotensin II in sodium and potassium handling in the distal nephron has been identified. This finding is likely to have important implications for understanding the effects of RAAS inhibition on whole body sodium and potassium balance.
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Affiliation(s)
- Bruno Sevá Pessôa
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
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