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Gohar EY, De Miguel C, Obi IE, Daugherty EM, Hyndman KA, Becker BK, Jin C, Sedaka R, Johnston JG, Liu P, Speed JS, Mitchell T, Kriegel AJ, Pollock JS, Pollock DM. Acclimation to a High-Salt Diet Is Sex Dependent. J Am Heart Assoc 2022; 11:e020450. [PMID: 35191321 PMCID: PMC9075092 DOI: 10.1161/jaha.120.020450] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/03/2021] [Indexed: 01/01/2023]
Abstract
Background Premenopausal women are less likely to develop hypertension and salt-related complications than are men, yet the impact of sex on mechanisms regulating Na+ homeostasis during dietary salt challenges is poorly defined. Here, we determined whether female rats have a more efficient capacity to acclimate to increased dietary salt intake challenge. Methods and Results Age-matched male and female Sprague Dawley rats maintained on a normal-salt (NS) diet (0.49% NaCl) were challenged with a 5-day high-salt diet (4.0% NaCl). We assessed serum, urinary, skin, and muscle electrolytes; total body water; and kidney Na+ transporters during the NS and high-salt diet phases. During the 5-day high-salt challenge, natriuresis increased more rapidly in females, whereas serum Na+ and body water concentration increased only in males. To determine if females are primed to handle changes in dietary salt, we asked the question whether the renal endothelin-1 natriuretic system is more active in female rats, compared with males. During the NS diet, female rats had a higher urinary endothelin-1 excretion rate than males. Moreover, Ingenuity Pathway Analysis of RNA sequencing data identified the enrichment of endothelin signaling pathway transcripts in the inner medulla of kidneys from NS-fed female rats compared with male counterparts. Notably, in human subjects who consumed an Na+-controlled diet (3314-3668 mg/day) for 3 days, women had a higher urinary endothelin-1 excretion rate than men, consistent with our findings in NS-fed rats. Conclusions These results suggest that female sex confers a greater ability to maintain Na+ homeostasis during acclimation to dietary Na+ challenges and indicate that the intrarenal endothelin-1 natriuretic pathway is enhanced in women.
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Affiliation(s)
- Eman Y. Gohar
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
- Present address:
Division of Nephrology and HypertensionVanderbilt University Medical CenterNashvilleTN
| | - Carmen De Miguel
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Ijeoma E. Obi
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Elizabeth M. Daugherty
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Kelly A. Hyndman
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Bryan K. Becker
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Chunhua Jin
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Randee Sedaka
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Jermaine G. Johnston
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - Pengyuan Liu
- Department of PhysiologyMedical College of WisconsinMilwaukeeWI
| | - Joshua S. Speed
- Department of PhysiologyUniversity of Mississippi Medical CenterJacksonMS
| | | | | | - Jennifer S. Pollock
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
| | - David M. Pollock
- Section of Cardio‐Renal Physiology & MedicineDivision of NephrologyDepartment of MedicineUniversity of Alabama at BirminghamAL
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Culshaw G, Binnie D, Dhaun N, Hadoke P, Bailey M, Webb D. The acute pressure natriuresis response is suppressed by selective ETA receptor blockade. Clin Sci (Lond) 2021; 136:CS20210937. [PMID: 34918049 PMCID: PMC8734438 DOI: 10.1042/cs20210937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/25/2021] [Accepted: 12/16/2021] [Indexed: 11/17/2022]
Abstract
Hypertension is a major risk factor for cardiovascular disease. In a significant minority of people, it develops when salt intake is increased (salt-sensitivity). It is not clear whether this represents impaired vascular function or disruption to the relationship between blood pressure (BP) and renal salt-handling (pressure natriuresis, PN). Endothelin-1 (ET-1) regulates BP via ETA and ETB receptor subtypes. Blockade of ETA receptors reduces BP, but promotes sodium retention by an unknown mechanism. ETB blockade increases both BP and sodium retention. We hypothesised that ETA blockade promotes sodium and water retention by suppressing PN. We also investigated whether suppression of PN might reflect off-target ETB blockade. Acute PN was induced by sequential arterial ligation in male Sprague Dawley rats. Intravenous atrasentan (ETA antagonist, 5mg/kg) halved the normal increase in medullary perfusion and reduced sodium and water excretion by >60%. This was not due to off-target ETB blockade because intravenous A-192621 (ETB antagonist, 10mg/kg) increased natriuresis by 50% without modifying medullary perfusion. In a separate experiment in salt-loaded rats monitored by radiotelemetry, oral atrasentan reduced systolic and diastolic BP by ~10mmHg, but additional oral A-192621 reversed these effects. Endogenous ETA stimulation has natriuretic effects mediated by renal vascular dilation while endogenous ETB stimulation in the kidney has antinatriuretic effects via renal tubular mechanisms. Pharmacological manipulation of vascular function with ET antagonists modifies the BP set-point, but even highly selective ETA antagonists attenuate PN, which may be associated with salt and water retention.
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Affiliation(s)
- Geoffrey J. Culshaw
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - David Binnie
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - Neeraj Dhaun
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - Patrick W.F. Hadoke
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - Matthew A. Bailey
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - David J. Webb
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
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Bądzyńska B, Vaneckova I, Sadowski J, Hojná S, Kompanowska-Jezierska E. Effects of systemic and renal intramedullary endothelin-1 receptor blockade on tissue NO and intrarenal hemodynamics in normotensive and hypertensive rats. Eur J Pharmacol 2021; 910:174445. [PMID: 34492284 DOI: 10.1016/j.ejphar.2021.174445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/28/2021] [Accepted: 08/24/2021] [Indexed: 10/20/2022]
Abstract
Endothelin 1 (ET-1) seems essential in salt-dependent hypertension, and activation of ETA receptors causes renal vasoconstriction. However, the response in the renal medulla and the role of tissue NO availability has never been adequately explored in vivo. We examined effects of ETA and ETB receptor blockade (atrasentan and BQ788) on blood pressure (MAP), medullary blood flow (MBF) and medullary tissue NO. Effects of systemic and intramedullary blocker application were compared in anesthetized normotensive ET-1-pretreated Sprague-Dawley rats (S-D), in salt-dependent hypertension (HS/UNX) and in spontaneously hypertensive rats (SHR). Total renal blood flow (RBF) was measured using a Transonic renal artery probe, MBF as laser-Doppler flux, and tissue NO signal using selective electrodes. In normotensive rats ET-1 significantly increased MAP, decreased RBF (-20%) and renal medullary NO. In HS/UNX rats atrasentan decreased MAP and increased medullary NO, earlier and more profoundly with intravenous infusion. In SHR atrasentan decreased MAP, more effectively with intravenous infusion; the increase in tissue NO (∼10%) was similar with both routes; however, only intramedullary atrasentan increased MBF. No consistent responses to BQ788 were seen. We confirmed dominant role of ETA receptors in regulation of blood pressure and renal hemodynamics in normotensive and hypertensive rats and provided novel evidence for the role of ETA in control of intrarenal NO bioavailability in salt-dependent and spontaneous hypertension. Under conditions of activation of the endothelin system ETB stimulation preserved medullary perfusion.
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Affiliation(s)
- Bożena Bądzyńska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, A. Pawińskiego 5, 02-106, Warsaw, Poland.
| | - Ivana Vaneckova
- Laboratory of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Czech Republic.
| | - Janusz Sadowski
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, A. Pawińskiego 5, 02-106, Warsaw, Poland.
| | - Silvie Hojná
- Laboratory of Experimental Hypertension, Institute of Physiology, Czech Academy of Sciences, Czech Republic.
| | - Elżbieta Kompanowska-Jezierska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, A. Pawińskiego 5, 02-106, Warsaw, Poland.
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Hyndman KA, Isaeva E, Palygin O, Mendoza LD, Rodan AR, Staruschenko A, Pollock JS. Role of collecting duct principal cell NOS1β in sodium and potassium homeostasis. Physiol Rep 2021; 9:e15080. [PMID: 34665521 PMCID: PMC8525323 DOI: 10.14814/phy2.15080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/15/2021] [Accepted: 09/27/2021] [Indexed: 12/15/2022] Open
Abstract
The nitric oxide (NO)-generating enzyme, NO synthase-1β (NOS1β), is essential for sodium (Na+ ) homeostasis and blood pressure control. We previously showed that collecting duct principal cell NOS1β is critical for inhibition of the epithelial sodium channel (ENaC) during high Na+ intake. Previous studies on freshly isolated cortical collecting ducts (CCD) demonstrated that exogenous NO promotes basolateral potassium (K+ ) conductance through basolateral channels, presumably Kir 4.1 (Kcnj10) and Kir 5.1 (Kcnj16). We, therefore, investigated the effects of NOS1β knockout on Kir 4.1/Kir 5.1 channel activity. Indeed, in CHO cells overexpressing NOS1β and Kir 4.1/Kir 5.1, the inhibition of NO signaling decreased channel activity. Male littermate control and principal cell NOS1β knockout mice (CDNOS1KO) on a 7-day, 4% NaCl diet (HSD) were used to detect changes in basolateral K+ conductance. We previously demonstrated that CDNOS1KO mice have high circulating aldosterone despite a high-salt diet and appropriately suppressed renin. We observed greater Kir 4.1 cortical abundance and significantly greater Kir 4.1/Kir 5.1 single-channel activity in the principal cells from CDNOS1KO mice. Moreover, blocking aldosterone action with in vivo spironolactone treatment resulted in lower Kir 4.1 abundance and greater plasma K+ in the CDNOS1KO mice compared to controls. Lowering K+ content in the HSD prevented the high aldosterone and greater plasma Na+ of CDNOS1KO mice and normalized Kir 4.1 abundance. We conclude that during chronic HSD, lack of NOS1β leads to increased plasma K+ , enhanced circulating aldosterone, and activation of ENaC and Kir 4.1/Kir 5.1 channels. Thus, principal cell NOS1β is required for the regulation of both Na+ and K+ by the kidney.
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Affiliation(s)
- Kelly A. Hyndman
- Department of MedicineDivision of NephrologySection of Cardio‐Renal Physiology and MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Elena Isaeva
- Department of Cellular Biology, Neurobiology and AnatomyMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Oleg Palygin
- Division of NephrologyDepartment of MedicineMedical University of South CarolinaCharlestonSouth CarolinaUSA
| | - Luciano D. Mendoza
- Department of MedicineDivision of NephrologySection of Cardio‐Renal Physiology and MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Aylin R. Rodan
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUtahUSA
- The Department of Internal MedicineDivision of Nephrology and HypertensionUniversity of UtahSalt Lake CityUtahUSA
- The Department of Human GeneticsUniversity of UtahSalt Lake CityUtahUSA
- The Medical ServiceVeterans Affairs Salt Lake City Health Care SystemSalt Lake CityUtahUSA
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and PhysiologyUniversity of South FloridaTampaFloridaUSA
- The James A. Haley Veterans HospitalTampaFloridaUSA
| | - Jennifer S. Pollock
- Department of MedicineDivision of NephrologySection of Cardio‐Renal Physiology and MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
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5
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Pati P, Valcin JA, Zhang D, Neder TH, Millender-Swain T, Allan JM, Sedaka R, Jin C, Becker BK, Pollock DM, Bailey SM, Pollock JS. Liver circadian clock disruption alters perivascular adipose tissue gene expression and aortic function in mice. Am J Physiol Regul Integr Comp Physiol 2021; 320:R960-R971. [PMID: 33881363 PMCID: PMC8285618 DOI: 10.1152/ajpregu.00128.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 03/22/2021] [Accepted: 04/15/2021] [Indexed: 12/15/2022]
Abstract
The liver plays a central role that influences cardiovascular disease outcomes through regulation of glucose and lipid metabolism. It is recognized that the local liver molecular clock regulates some liver-derived metabolites. However, it is unknown whether the liver clock may impact cardiovascular function. Perivascular adipose tissue (PVAT) is a specialized type of adipose tissue surrounding blood vessels. Importantly, cross talk between the endothelium and PVAT via vasoactive factors is critical for vascular function. Therefore, we designed studies to test the hypothesis that cardiovascular function, including PVAT function, is impaired in mice with liver-specific circadian clock disruption. Bmal1 is a core circadian clock gene, thus studies were undertaken in male hepatocyte-specific Bmal1 knockout (HBK) mice and littermate controls (i.e., flox mice). HBK mice showed significantly elevated plasma levels of β-hydroxybutyrate, nonesterified fatty acids/free fatty acids, triglycerides, and insulin-like growth factor 1 compared with flox mice. Thoracic aorta PVAT in HBK mice had increased mRNA expression of several key regulatory and metabolic genes, Ppargc1a, Pparg, Adipoq, Lpl, and Ucp1, suggesting altered PVAT energy metabolism and thermogenesis. Sensitivity to acetylcholine-induced vasorelaxation was significantly decreased in the aortae of HBK mice with PVAT attached compared with aortae of HBK mice with PVAT removed, however, aortic vasorelaxation in flox mice showed no differences with or without attached PVAT. HBK mice had a significantly lower systolic blood pressure during the inactive period of the day. These new findings establish a novel role of the liver circadian clock in regulating PVAT metabolic gene expression and PVAT-mediated aortic vascular function.
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Affiliation(s)
- Paramita Pati
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jennifer A Valcin
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Dingguo Zhang
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Thomas H Neder
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Telisha Millender-Swain
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - John Miller Allan
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Randee Sedaka
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Chunhua Jin
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Bryan K Becker
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David M Pollock
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Shannon M Bailey
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jennifer S Pollock
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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Sedaka R, Hyndman KA, Mironova E, Stockand JD, Pollock JS. High salt intake induces collecting duct HDAC1-dependent NO signaling. Am J Physiol Renal Physiol 2021; 320:F297-F307. [PMID: 33356953 PMCID: PMC7988806 DOI: 10.1152/ajprenal.00323.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/07/2020] [Accepted: 12/15/2020] [Indexed: 01/13/2023] Open
Abstract
We reported that high salt (HS) intake stimulates renal collecting duct (CD) endothelin (ET) type B receptor (ETBR)/nitric oxide (NO) synthase 1β (NOS1β)-dependent NO production inhibiting the epithelial sodium channel (ENaC) promoting natriuresis. However, the mechanism underlying the HS-induced increase of NO production is unclear. Histone deacetylase 1 (HDAC1) responds to increased fluid flow, as can occur in the CD during HS intake. The renal inner medulla (IM), in particular the IMCD, has the highest NOS1 activity within the kidney. Hence, we hypothesized that HS intake provokes HDAC1 activation of NO production in the IM. HS intake for 1 wk significantly increased HDAC1 abundance in the IM. Ex vivo treatment of dissociated IM from HS-fed mice with a selective HDAC1 inhibitor (MS-275) decreased NO production with no change in ET-1 peptide or mRNA levels. We further investigated the role of the ET-1/ETBR/NOS1β signaling pathway with chronic ETBR blockade (A-192621). Although NO was decreased and ET-1 levels were elevated in the dissociated IM from HS-fed mice treated with A-192621, ex vivo MS-275 did not further change NO or ET-1 levels suggesting that HDAC1-mediated NO production is regulated at the level or downstream of ETBR activation. In split-open CDs from HS-fed mice, patch clamp analysis revealed significantly higher ENaC activity after MS-275 pretreatment, which was abrogated by an exogenous NO donor. Moreover, flow-induced increases in mIMCD-3 cell NO production were blunted by HDAC1 or calcium inhibition. Taken together, these findings indicate that HS intake induces HDAC1-dependent activation of the ETBR/NO pathway contributing to the natriuretic response.
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Affiliation(s)
- Randee Sedaka
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Kelly A Hyndman
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Elena Mironova
- Department of Cellular and Integrative Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - James D Stockand
- Department of Cellular and Integrative Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Jennifer S Pollock
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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7
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Zhang D, Jin C, Obi IE, Rhoads MK, Soliman RH, Sedaka RS, Allan JM, Tao B, Speed JS, Pollock JS, Pollock DM. Loss of circadian gene Bmal1 in the collecting duct lowers blood pressure in male, but not female, mice. Am J Physiol Renal Physiol 2020; 318:F710-F719. [PMID: 31904281 PMCID: PMC7099501 DOI: 10.1152/ajprenal.00364.2019] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 12/11/2019] [Accepted: 01/03/2020] [Indexed: 01/19/2023] Open
Abstract
Kidney function follows a 24-h rhythm subject to regulation by circadian genes including the transcription factor Bmal1. A high-salt diet induces a phase shift in Bmal1 expression in the renal inner medulla that is dependent on endothelin type B (ETB) receptors. Furthermore, ETB receptor-mediated natriuresis is sex dependent. Therefore, experiments tested the hypothesis that collecting duct Bmal1 regulates blood pressure in a sex-dependent manner. We generated a mouse model that lacks Bmal1 expression in the collecting duct, where ETB receptor abundance is highest. Male, but not female, collecting duct Bmal1 knockout (CDBmal1KO) mice had significantly lower 24-h mean arterial pressure (MAP) than flox controls (105 ± 2 vs. 112 ± 3 mmHg for male mice and 106 ± 1 vs. 108 ± 1 mmHg for female mice, by telemetry). After 6 days on a high-salt (4% NaCl) diet, MAP remained significantly lower in male CDBmal1KO mice than in male flox control mice (107 ± 2 vs. 113 ± 1 mmHg), with no significant differences between genotypes in female mice (108 ± 2 vs. 109 ± 1 mmHg). ETB receptor blockade for another 6 days increased MAP similarly in both male and female CDBmal1KO and flox control mice. However, MAP remained lower in male CDBmal1KO mice than in male flox control mice (124 ± 2 vs. 130 ± 2 mmHg). No significant differences were observed between female CDBmal1KO and flox mice during ETB blockade (130 ± 2 vs. 127 ± 2 mmHg). There were no significant genotype differences in amplitude or phase of MAP in either sex. These data suggest that collecting duct Bmal1 has no role in circadian MAP but plays an important role in overall blood pressure in male, but not female, mice.
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Affiliation(s)
- Dingguo Zhang
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Chunhua Jin
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ijeoma E Obi
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Megan K Rhoads
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Reham H Soliman
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Randee S Sedaka
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - J Miller Allan
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Binli Tao
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Joshua S Speed
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jennifer S Pollock
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David M Pollock
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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Leipziger J, Praetorius H. Renal Autocrine and Paracrine Signaling: A Story of Self-protection. Physiol Rev 2020; 100:1229-1289. [PMID: 31999508 DOI: 10.1152/physrev.00014.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Autocrine and paracrine signaling in the kidney adds an extra level of diversity and complexity to renal physiology. The extensive scientific production on the topic precludes easy understanding of the fundamental purpose of the vast number of molecules and systems that influence the renal function. This systematic review provides the broader pen strokes for a collected image of renal paracrine signaling. First, we recapitulate the essence of each paracrine system one by one. Thereafter the single components are merged into an overarching physiological concept. The presented survey shows that despite the diversity in the web of paracrine factors, the collected effect on renal function may not be complicated after all. In essence, paracrine activation provides an intelligent system that perceives minor perturbations and reacts with a coordinated and integrated tissue response that relieves the work load from the renal epithelia and favors diuresis and natriuresis. We suggest that the overall function of paracrine signaling is reno-protection and argue that renal paracrine signaling and self-regulation are two sides of the same coin. Thus local paracrine signaling is an intrinsic function of the kidney, and the overall renal effect of changes in blood pressure, volume load, and systemic hormones will always be tinted by its paracrine status.
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Affiliation(s)
- Jens Leipziger
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
| | - Helle Praetorius
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
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Kim DG, Choi JW, Jo IJ, Kim MJ, Lee HS, Hong SH, Song HJ, Bae GS, Park SJ. Berberine ameliorates lipopolysaccharide‑induced inflammatory responses in mouse inner medullary collecting duct‑3 cells by downregulation of NF‑κB pathway. Mol Med Rep 2019; 21:258-266. [PMID: 31746359 PMCID: PMC6896374 DOI: 10.3892/mmr.2019.10823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 10/08/2019] [Indexed: 12/17/2022] Open
Abstract
The major role of inner medullary collecting duct (IMCD) cells is to maintain water and sodium homeostasis. In addition to the major role, it also participates in the protection of renal and systemic inflammation. Although IMCD cells could take part in renal and systemic inflammation, investigations on renal inflammation in IMCD cells have rarely been reported. Although berberine (BBR) has been reported to show diverse pharmacological effects, its anti-inflammatory and protective effects on IMCD cells have not been studied. Therefore, in the present study, we examined the anti-inflammatory and protective effects of BBR in mouse IMCD-3 (mIMCD-3) cells against lipopolysaccharide (LPS). An MTT assay was carried out to investigate the toxicity of BBR on mIMCD-3 cells. Reverse transcription quantitative-PCR and western blotting were performed to analysis pro-inflammatory molecules and cytokines. Mechanisms of BBR were examined by western blotting and immunocytochemistry. According to previous studies, pro-inflammatory molecules, such as inducible nitric oxide synthase and cyclooxygenase-2, and pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6 and tumor necrosis factor-α are increased in LPS-exposed mIMCD-3 cells. However, the production of these pro-inflammatory molecules is significantly inhibited by treatment with BBR. In addition, BBR inhibited translocation of nuclear factor (NF)-κB p65 from the cytosol to the nucleus, and degradation of inhibitory κ-Bα in LPS-exposed mIMCD-3 cells. In conclusion, BBR could inhibit renal inflammatory responses via inhibition of NF-κB signaling and ultimately contribute to amelioration of renal injury during systemic inflammation.
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Affiliation(s)
- Dong-Gu Kim
- Hanbang Cardio‑Renal Syndrome Research Center, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Ji-Won Choi
- Hanbang Cardio‑Renal Syndrome Research Center, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Il-Joo Jo
- Division of Beauty Sciences, School of Natural Sciences, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Myoung-Jin Kim
- Department of Herbology, School of Korean Medicine, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Ho-Sub Lee
- Hanbang Cardio‑Renal Syndrome Research Center, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Seung-Heon Hong
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Ho-Joon Song
- Department of Herbology, School of Korean Medicine, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Gi-Sang Bae
- Hanbang Cardio‑Renal Syndrome Research Center, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Sung-Joo Park
- Hanbang Cardio‑Renal Syndrome Research Center, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
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10
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De Miguel C, Sedaka R, Kasztan M, Lever JM, Sonnenberger M, Abad A, Jin C, Carmines PK, Pollock DM, Pollock JS. Tauroursodeoxycholic acid (TUDCA) abolishes chronic high salt-induced renal injury and inflammation. Acta Physiol (Oxf) 2019; 226:e13227. [PMID: 30501003 DOI: 10.1111/apha.13227] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 10/23/2018] [Accepted: 11/22/2018] [Indexed: 12/23/2022]
Abstract
AIM Chronic high salt intake exaggerates renal injury and inflammation, especially with the loss of functional ETB receptors. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and bile salt that is approved for the treatment of hepatic diseases. Our aim was to determine whether TUDCA is reno-protective in a model of ETB receptor deficiency with chronic high salt-induced renal injury and inflammation. METHODS ETB -deficient and transgenic control rats were placed on normal (0.8% NaCl) or high salt (8% NaCl) diet for 3 weeks, receiving TUDCA (400 mg/kg/d; ip) or vehicle. Histological and biochemical markers of kidney injury, renal cell death and renal inflammation were assessed. RESULTS In ETB -deficient rats, high salt diet significantly increased glomerular and proximal tubular histological injury, proteinuria, albuminuria, excretion of tubular injury markers KIM-1 and NGAL, renal cortical cell death and renal CD4+ T cell numbers. TUDCA treatment increased proximal tubule megalin expression as well as prevented high salt diet-induced glomerular and tubular damage in ETB -deficient rats, as indicated by reduced kidney injury markers, decreased glomerular permeability and proximal tubule brush border restoration, as well as reduced renal inflammation. However, TUDCA had no significant effect on blood pressure. CONCLUSIONS TUDCA protects against the development of glomerular and proximal tubular damage, decreases renal cell death and inflammation in the renal cortex in rats with ETB receptor dysfunction on a chronic high salt diet. These results highlight the potential use of TUDCA as a preventive tool against chronic high salt induced renal damage.
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Affiliation(s)
- Carmen De Miguel
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Randee Sedaka
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Malgorzata Kasztan
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Jeremie M. Lever
- Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Michelle Sonnenberger
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Andrew Abad
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Chunhua Jin
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Pamela K. Carmines
- Department of Cellular and Integrative Physiology University of Nebraska Medical Center Omaha Nebraska
| | - David M. Pollock
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Jennifer S. Pollock
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
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11
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Gonzalez-Vicente A, Saez F, Monzon CM, Asirwatham J, Garvin JL. Thick Ascending Limb Sodium Transport in the Pathogenesis of Hypertension. Physiol Rev 2019; 99:235-309. [PMID: 30354966 DOI: 10.1152/physrev.00055.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The thick ascending limb plays a key role in maintaining water and electrolyte balance. The importance of this segment in regulating blood pressure is evidenced by the effect of loop diuretics or local genetic defects on this parameter. Hormones and factors produced by thick ascending limbs have both autocrine and paracrine effects, which can extend prohypertensive signaling to other structures of the nephron. In this review, we discuss the role of the thick ascending limb in the development of hypertension, not as a sole participant, but one that works within the rich biological context of the renal medulla. We first provide an overview of the basic physiology of the segment and the anatomical considerations necessary to understand its relationship with other renal structures. We explore the physiopathological changes in thick ascending limbs occurring in both genetic and induced animal models of hypertension. We then discuss the racial differences and genetic defects that affect blood pressure in humans through changes in thick ascending limb transport rates. Throughout the text, we scrutinize methodologies and discuss the limitations of research techniques that, when overlooked, can lead investigators to make erroneous conclusions. Thus, in addition to advancing an understanding of the basic mechanisms of physiology, the ultimate goal of this work is to understand our research tools, to make better use of them, and to contextualize research data. Future advances in renal hypertension research will require not only collection of new experimental data, but also integration of our current knowledge.
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Affiliation(s)
| | - Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Casandra M Monzon
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jessica Asirwatham
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
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12
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Aoki S, Saito-Hakoda A, Yoshikawa T, Shimizu K, Kisu K, Suzuki S, Takagi K, Mizumoto S, Yamada S, van Kuppevelt TH, Yokoyama A, Matsusaka T, Sato H, Ito S, Sugawara A. The reduction of heparan sulphate in the glomerular basement membrane does not augment urinary albumin excretion. Nephrol Dial Transplant 2018; 33:26-33. [PMID: 28992095 DOI: 10.1093/ndt/gfx218] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 04/23/2017] [Indexed: 01/12/2023] Open
Abstract
Background Heparan sulphate proteoglycan (HSPG) is present in the glomerular basement membrane (GBM) and is thought to play a major role in the glomerular charge barrier. Reductions and structural alterations of HSPG are observed in different types of kidney diseases accompanied by proteinuria. However, their causal relations remain unknown. Methods We generated podocyte-specific exostosin-like 3 gene (Extl3) knockout mice (Extl3KO) using a Cre-loxP recombination approach. A reduction of HSPG was expected in the GBM of these mice, because EXTL3 is involved in its synthesis. Mice were separated into three groups, according to the loads on the glomeruli: a high-protein diet group, a high-protein and high-sodium diet group and a hyperglycaemic group induced by streptozotocin treatment in addition to maintenance on a high-protein and high-sodium diet. The urinary albumin:creatinine ratio was measured at 7, 11, 15 and 19 weeks of age. Renal histology was also investigated. Results Podocyte-specific expression of Cre recombinase was detected by immunohistochemistry. Moreover, immunofluorescent staining demonstrated a significant reduction of HSPG in the GBM. Electron microscopy showed irregularities in the GBM and effacement of the foot processes in Extl3KO. The values of the urinary albumin:creatinine ratio were within the range of microalbuminuria in all groups and did not significantly differ between the control mice and Extl3KO. Conclusions The reduction of HSPG in the GBM did not augment urinary albumin excretion. HSPG's anionic charge appears to contribute little to the glomerular charge barrier.
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Affiliation(s)
- Satoshi Aoki
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akiko Saito-Hakoda
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Takeo Yoshikawa
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kyoko Shimizu
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kiyomi Kisu
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Susumu Suzuki
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kiyoshi Takagi
- Department of Pathology and Histotechnology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijyo University, Nagoya, Aichi, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijyo University, Nagoya, Aichi, Japan
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Atsushi Yokoyama
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Taiji Matsusaka
- Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Hiroshi Sato
- Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Miyagi, Japan
| | - Sadayoshi Ito
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akira Sugawara
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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13
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Speed JS, Hyndman KA, Roth K, Heimlich JB, Kasztan M, Fox BM, Johnston JG, Becker BK, Jin C, Gamble KL, Young ME, Pollock JS, Pollock DM. High dietary sodium causes dyssynchrony of the renal molecular clock in rats. Am J Physiol Renal Physiol 2018; 314:F89-F98. [PMID: 28971988 PMCID: PMC5866350 DOI: 10.1152/ajprenal.00028.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 08/31/2017] [Accepted: 09/22/2017] [Indexed: 11/22/2022] Open
Abstract
Speed JS, Hyndman KA, Roth K, Heimlich JB, Kasztan M, Fox BM, Johnston JG, Becker BK, Jin C, Gamble KL, Young ME, Pollock JS, Pollock DM. High dietary sodium causes dyssynchrony of the renal molecular clock in rats. Am J Physiol Renal Physiol 314: F89-F98, 2018. First published September 27, 2017; doi:10.1152/ajprenal.00028.2017.-Dyssynchrony of circadian rhythms is associated with various disorders, including cardiovascular and metabolic diseases. The cell autonomous molecular clock maintains circadian control; however, environmental factors that may cause circadian dyssynchrony either within or between organ systems are poorly understood. Our laboratory recently reported that the endothelin (ET-1) B (ETB) receptor functions to facilitate Na+ excretion in a time of day-dependent manner. Therefore, the present study was designed to determine whether high salt (HS) intake leads to circadian dyssynchrony within the kidney and whether the renal endothelin system contributes to control of the renal molecular clock. We observed that HS feeding led to region-specific alterations in circadian clock components within the kidney. For instance, HS caused a significant 5.5-h phase delay in the peak expression of Bmal1 and suppressed Cry1 and Per2 expression in the renal inner medulla, but not the renal cortex, of control rats. The phase delay in Bmal1 expression appears to be mediated by ET-1 because this phenomenon was not observed in the ETB-deficient rat. In cultured inner medullary collecting duct cells, ET-1 suppressed Bmal1 mRNA expression. Furthermore, Bmal1 knockdown in these cells reduced epithelial Na+ channel expression. These data reveal that HS feeding leads to intrarenal circadian dyssynchrony mediated, in part, through activation of ETB receptors within the renal inner medulla.
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Affiliation(s)
- Joshua S Speed
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Kelly A Hyndman
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Kaehler Roth
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | | | - Malgorzata Kasztan
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Brandon M Fox
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Jermaine G Johnston
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Bryan K Becker
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Chunhua Jin
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Karen L Gamble
- Department of Psychiatry, University of Alabama at Birmingham , Birmingham, Alabama
| | - Martin E Young
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham , Birmingham, Alabama
| | - Jennifer S Pollock
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - David M Pollock
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
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14
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Speed JS, Hyndman KA, Kasztan M, Johnston JG, Roth KJ, Titze JM, Pollock DM. Diurnal pattern in skin Na + and water content is associated with salt-sensitive hypertension in ET B receptor-deficient rats. Am J Physiol Regul Integr Comp Physiol 2017; 314:R544-R551. [PMID: 29351432 DOI: 10.1152/ajpregu.00312.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Impairment in the ability of the skin to properly store Na+ nonosmotically (without water) has recently been hypothesized as contributing to salt-sensitive hypertension. Our laboratory has shown that endothelial production of endothelin-1 (ET-1) is crucial to skin Na+ handling. Furthermore, it is well established that loss of endothelin type B receptor (ETB) receptor function impairs Na+ excretion by the kidney. Thus we hypothesized that rats lacking functional ETB receptors (ETB-def) will have a reduced capacity of the skin to store Na+ during chronic high-salt (HS) intake. We observed that ETB-def rats exhibited salt-sensitive hypertension with an approximate doubling in the diurnal amplitude of mean arterial pressure compared with genetic control rats on a HS diet. Two weeks of HS diet significantly increased skin Na+ content relative to water; however, there was no significant difference between control and ETB-def rats. Interestingly, HS intake led to a 19% increase in skin Na+ and 16% increase in water content (relative to dry wt.) during the active phase (zeitgeber time 16) versus inactive phase (zeitgeber time 4, P < 0.05) in ETB-def rats. There was no significant circadian variation in total skin Na+ or water content of control rats fed normal or HS. These data indicate that ETB receptors have little influence on the ability to store Na+ nonosmotically in the skin during long-term HS intake but, rather, appear to regulate diurnal rhythms in skin Na+ content and circadian blood pressure rhythms associated with a HS diet.
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Affiliation(s)
- Joshua S Speed
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Kelly A Hyndman
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Malgorzata Kasztan
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Jermaine G Johnston
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Kaehler J Roth
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Jens M Titze
- Cardiovasular and Metabolic Disorders, National University of Singapore Medical School, Singapore
| | - David M Pollock
- Cardio-Renal Physiology and Medicine, Department of Medicine, Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
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15
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Just A. Salt control. Focus on “High salt induces autocrine actions of ET-1 on inner medullary collecting duct NO production via upregulated ET B receptor expression”. Am J Physiol Regul Integr Comp Physiol 2016; 311:R374-6. [DOI: 10.1152/ajpregu.00329.2016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 07/27/2016] [Indexed: 11/22/2022]
Affiliation(s)
- Armin Just
- Physiologisches Institut, Albert-Ludwigs-Universität, Freiburg, Germany
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