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Hua D, Huang W, Huang W, Xie Q, Tang L, Wu X, Gao M, Xu T, Zhang Y, Li P, Sun W, Kong X. TRPV1 signaling of perirenal adipose tissue promotes DOCA-Salt-induced hypertension and kidney injury. J Hypertens 2024; 42:1409-1420. [PMID: 38690943 DOI: 10.1097/hjh.0000000000003748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
BACKGROUND Denervation of renal or perirenal adipose tissue (PRAT) can reduce arterial blood pressure in various hypertensive experimental models. Trpv1 (transient receptor potential vanillin 1) channel is highly expressed in the renal sensory nerves and the dorsal root ganglias (DRGs) projected by PRAT. However, it is currently unclear whether Trpv1 in DRGs projected from PRAT can regulate renal hypertension. METHODS We used resintoxin (RTX) to block the afferent sensory nerves of rat PRAT. We also constructed Trpv1 -/- mice and Trpv1 +/- mice or used the injection of AAV2-retro-shTrpv1 to detect the effects of Trpv1 knockout or knockdown of PRAT-projected DRGs on deoxycorticosterone acetate (DOCA)-Salt-induced hypertension and kidney injury. RESULTS Blocking the afferent sensory nerves of PRAT with RTX can alleviate DOCA-Salt-induced hypertension and renal injury in rats. And this blockade reduces the expression of Trpv1 in the DRGs projected by PRAT. Injecting AAV2-retro-shTrpv1 into the PRAT of DOCA-Salt mice also achieved the same therapeutic effect. However, DOCA-Salt-induced hypertension and renal injury can be treated in Trpv1 +/- mice but not alleviated or even worsened in Trpv1 -/- mice, possibly because of compensatory increase of Trpv5 in DRG of Trpv1 -/- mice. CONCLUSION Reducing, rather than eliminating, Trpv1 in DRG from PRAT-projection can reduce blood pressure and kidney damage in DOCA-Salt in rats or mice. Trpv1 in PRAT-DRGs may serve as a therapeutic target for salt-sensitive hypertension and its renal complications.
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Affiliation(s)
- Dongxu Hua
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Wanlin Huang
- Department of Cardiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Wen Huang
- Department of Cardiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Qiyang Xie
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Lu Tang
- Department of Cardiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, P.R. China
| | - Xiaoguang Wu
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Min Gao
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Tianhua Xu
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Yue Zhang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Peng Li
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine
| | - Wei Sun
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine
| | - Xiangqing Kong
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine
- Department of Cardiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, P.R. China
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2
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Zhang M, Liu M, Wang W, Ren Z, Wang P, Xue Y, Wang X. The salt sensitivity of Drd4-null mice is associated with the upregulations of sodium transporters in kidneys. Hypertens Res 2024; 47:2144-2156. [PMID: 38778170 DOI: 10.1038/s41440-024-01724-5] [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: 01/25/2024] [Revised: 04/01/2024] [Accepted: 04/21/2024] [Indexed: 05/25/2024]
Abstract
To explore the mechanism of the hypertension in dopamine receptor-4 (Drd4) null mice, we determined the salt sensitivity and renal sodium transport proteins in Drd4-/- and Drd4+/+ mice with varied salt diets. On normal NaCl diet (NS), mean arterial pressures (MAP, telemetry) were higher in Drd4-/- than Drd4+/+; Low NaCl diet (LS) tended to decrease MAP in both strains; high NaCl diet (HS) elevated MAP with sodium excretion decreased and pressure-natriuresis curve shifted to right in Drd4-/- relative to Drd4+/+ mice. Drd4-/- mice exhibited increased renal sodium-hydrogen exchanger 3 (NHE3), sodium-potassium-2-chloride cotransporter (NKCC2), sodium-chloride cotransporter (NCC), and outer medullary α-epithelial sodium channel (αENaC) on NS, decreased NKCC2, NCC, αENaC, and αNa+-K+-ATPase on LS, and increased αENaC on HS. NKCC2, NCC, αENaC, and αNa+-K+-ATPase in plasma membrane were greater in Drd4-/- than in Drd4+/+ mice with HS. D4R was expressed in proximal and distal convoluted tubules, thick ascending limbs, and outer medullary collecting ducts and colocalized with NKCC2 and NCC. The phosphorylation of NKCC2 was enhanced but ubiquitination was reduced in the KO mice. There were no differences between the mouse strains in serum aldosterone concentrations and urinary dopamine excretions despite their changes with diets. The mRNA expressions of renal NHE3, NKCC2, NCC, and αENaC on NS were not altered in Drd4-/- mice. Thus, increased protein expressions of NHE3, NKCC2, NCC and αENaC are associated with hypertension in Drd4-/- mice; increased plasma membrane protein expression of NKCC2, NCC, αENaC, and αNa+-K+-ATPase may mediate the salt sensitivity of Drd4-/- mice.
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Affiliation(s)
- Mingzhuo Zhang
- The Core Laboratory for Clinical Research, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
- Department of Nephrology, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
| | - Mingda Liu
- The Core Laboratory for Clinical Research, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
| | - Weiwan Wang
- The Core Laboratory for Clinical Research, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
| | - Zhiyun Ren
- The Core Laboratory for Clinical Research, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
| | - Ping Wang
- The Core Laboratory for Clinical Research, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
| | - Ying Xue
- The Core Laboratory for Clinical Research, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
| | - Xiaoyan Wang
- The Core Laboratory for Clinical Research, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China.
- Department of Nephrology, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China.
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3
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Ralph DL, Ha D, Lei H, Priver TS, Smith SD, McFarlin BE, Schwindt S, Pandya D, Koepsell H, Pastor-Soler NM, Edwards A, McDonough AA. Potassium-Alkali-Enriched Diet, Hypertension, and Proteinuria following Uninephrectomy. J Am Soc Nephrol 2024:00001751-990000000-00357. [PMID: 38913441 DOI: 10.1681/asn.0000000000000420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 06/10/2024] [Indexed: 06/26/2024] Open
Abstract
Key Points
A K-alkali–enriched diet blunted post-uninephrectomy hypertension and facilitated acid clearance by suppressing Na+ reabsorption.Uninephrectomy-associated proteinuria could be attributed to elevated single-nephron GFR and downregulation of megalin, which reduced fractional protein endocytosis.
Background
Losing or donating a kidney is associated with risks of developing hypertension and albuminuria. Few studies address mechanisms or interventions. We investigate the potential benefits of a K+- alkali–enriched diet and the mechanisms underlying proteinuria.
Methods
Male Sprague Dawley rats were fed either a 2% NaCl+0.95% KCl diet (HNa-LK) or a 0.74% NaCl+3% K+-alkali diet (HK-alk) for 3 weeks before uninephrectomy and then maintained on respective diets for 12 weeks. BP (by tail-cuff), urine, blood, and kidney proteins were analyzed before and after uninephrectomy.
Results
Before uninephrectomy, HK-alk–fed versus HNa-LK–fed rats exhibited similar BPs and plasma [K+], [Na+], but lower proximal (NHE3, sodium bicarbonate cotransporter 1, NaPi2) and higher distal (NCC, ENaC, and pendrin) transporter abundance, a pattern facilitating K+ and HCO3
− secretion. After uninephrectomy, single-nephron GFR increased 50% and Li+ clearance doubled with both diets; in HK-alk versus HNa-LK, the increase in BP was less and ammoniagenesis was lower, abundance of proximal tubule transporters remained lower, ENaC-α fell, and NCCp increased, consistent with K+ conservation. After uninephrectomy, independent of diet, albuminuria increased eight-fold and abundance of endocytic receptors was reduced (megalin by 44%, disabled homolog 2 by 25%–35%) and kidney injury molecule-1 was increased.
Conclusions
The K-alkali–enriched diet blunted post-uninephrectomy hypertension and facilitated acid clearance by suppressing proximal Na+ transporters and increasing K+-alkali secretion. Furthermore, uninephrectomy-associated proteinuria could be attributed, at least in part, to elevated single-nephron GFR coupled with downregulation of megalin, which reduced fractional protein endocytosis and Vmax.
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Affiliation(s)
- Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Darren Ha
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Hillmin Lei
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Taylor S Priver
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Scotti D Smith
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Brandon E McFarlin
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Seth Schwindt
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Drishti Pandya
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Hermann Koepsell
- Institute for Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Nuria M Pastor-Soler
- Division of Nephrology, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Aurelie Edwards
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
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4
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Al-Maraghi A, Aamer W, Ziab M, Aliyev E, Elbashir N, Hussein S, Palaniswamy S, Anand D, Love DR, Charles A, A S Akil A, Fakhro KA. A loss-of-function AGTR1 variant in a critically-ill infant with renal tubular dysgenesis: case presentation and literature review. BMC Nephrol 2024; 25:139. [PMID: 38649831 PMCID: PMC11034062 DOI: 10.1186/s12882-024-03569-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 04/02/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Renal tubular dysgenesis (RTD) is a severe disorder with poor prognosis significantly impacting the proximal tubules of the kidney while maintaining an anatomically normal gross structure. The genetic origin of RTD, involving variants in the ACE, REN, AGT, and AGTR1 genes, affects various enzymes or receptors within the Renin angiotensin system (RAS). This condition manifests prenatally with oligohydramninos and postnatally with persistent anuria, severe refractory hypotension, and defects in skull ossification. CASE PRESENTATION In this report, we describe a case of a female patient who, despite receiving multi vasopressor treatment, experienced persistent hypotension, ultimately resulting in early death at five days of age. While there was a history of parental consanguinity, no reported family history of renal disease existed. Blood samples from the parents and the remaining DNA sample of the patient underwent Whole Genome Sequencing (WGS). The genetic analysis revealed a rare homozygous loss of function variant (NM_000685.5; c.415C > T; p.Arg139*) in the Angiotensin II Receptor Type 1 (AGTR1) gene. CONCLUSION This case highlights the consequence of loss-of-function variants in AGTR1 gene leading to RTD, which is characterized by high mortality rate at birth or during the neonatal period. Furthermore, we provide a comprehensive review of previously reported variants in the AGTR1 gene, which is the least encountered genetic cause of RTD, along with their associated clinical features.
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Affiliation(s)
- Aljazi Al-Maraghi
- Laboratory of Genomic Medicine, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Waleed Aamer
- Laboratory of Genomic Medicine, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Mubarak Ziab
- Department of Human Genetics-Precision Medicine in Diabetes Prevention, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Elbay Aliyev
- Laboratory of Genomic Medicine, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Najwa Elbashir
- Laboratory of Genomic Medicine, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Sura Hussein
- Laboratory of Genomic Medicine, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | | | - Dhullipala Anand
- Neonatology Division, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Donald R Love
- Genetic Pathology, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Adrian Charles
- Anatomical Pathology, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Ammira A S Akil
- Department of Human Genetics-Precision Medicine in Diabetes Prevention, Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Khalid A Fakhro
- Laboratory of Genomic Medicine, Sidra Medicine, P.O. Box 26999, Doha, Qatar.
- Department of Human Genetics-Precision Medicine in Diabetes Prevention, Sidra Medicine, P.O. Box 26999, Doha, Qatar.
- College of Health and Life Sciences, Hamad Bin Khalifa University, P.O. Box 34110, Doha, Qatar.
- Department of Genetic Medicine, Weill Cornell Medical College, P.O. Box 24144, Doha, Qatar.
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5
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McDonough AA, Harris AN, Xiong LI, Layton AT. Sex differences in renal transporters: assessment and functional consequences. Nat Rev Nephrol 2024; 20:21-36. [PMID: 37684523 PMCID: PMC11090267 DOI: 10.1038/s41581-023-00757-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2023] [Indexed: 09/10/2023]
Abstract
Mammalian kidneys are specialized to maintain fluid and electrolyte homeostasis. The epithelial transport processes along the renal tubule that match output to input have long been the subject of experimental and theoretical study. However, emerging data have identified a new dimension of investigation: sex. Like most tissues, the structure and function of the kidney is regulated by sex hormones and chromosomes. Available data demonstrate sex differences in the abundance of kidney solute and electrolyte transporters, establishing that renal tubular organization and operation are distinctly different in females and males. Newer studies have provided insights into the physiological consequences of these sex differences. Computational simulations predict that sex differences in transporter abundance are likely driven to optimize reproduction, enabling adaptive responses to the nutritional requirements of serial pregnancies and lactation - normal life-cycle changes that challenge the ability of renal transporters to maintain fluid and electrolyte homeostasis. Later in life, females may also undergo menopause, which is associated with changes in disease risk. Although numerous knowledge gaps remain, ongoing studies will provide further insights into the sex-specific mechanisms of sodium, potassium, acid-base and volume physiology throughout the life cycle, which may lead to therapeutic opportunities.
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Affiliation(s)
- Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
| | - Autumn N Harris
- Department of Small Animal Clinical Sciences, University of Florida, College of Veterinary Medicine, Gainesville, FL, USA
| | - Lingyun Ivy Xiong
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA
| | - Anita T Layton
- Departments of Applied Mathematics and Biology, University of Waterloo, Waterloo, Ontario, Canada
- Cheriton School of Computer Science, University of Waterloo, Waterloo, Ontario, Canada
- School of Pharmacy, University of Waterloo, Waterloo, Ontario, Canada
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6
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Pereira‐Acácio A, Veloso‐Santos JPM, Alves‐Bezerra D, Costa‐Sarmento G, Muzi‐Filho H, Vieyra A. Different antihypertensive and metabolic responses to rostafuroxin in undernourished and normonourished male rats: Outcomes on bodily Na + handling. Physiol Rep 2023; 11:e15820. [PMID: 37667414 PMCID: PMC10477346 DOI: 10.14814/phy2.15820] [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: 07/28/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/06/2023] Open
Abstract
Hypertension is a pandemic nowadays. We aimed to investigate whether chronic undernutrition modifies the response to the antihypertensive drug rostafuroxin in juvenile hypertensive rats. Chronic undernutrition was induced in male rats using a multideficient diet known as the Regional Basic Diet (RBD), mimicking alimentary habits in impoverished regions worldwide. Animals were given RBD-or a control/CTRL normal diet for rodents-from weaning to 90 days, and rostafuroxin (1 mg/kg body mass) was orally administered from day 60 onwards. For the last 2 days, the rats were hosted in metabolic cages to measure food/energy, water, Na+ ingestion, and urinary volume. Rostafuroxin increased food/energy/Na+ intake in CTRL and RBD rats but had opposite effects on Na+ balance (intake minus urinary excretion). The drug normalized the decreased plasma Na+ concentration in RBD rats, increased urinary volume in RBD but not in CTRL, and decreased and increased urinary Na+ concentration in the RBD and CTRL groups, respectively. Rostafuroxin decreased the ouabain-sensitive (Na+ +K+ )ATPase and increased the ouabain-resistant Na+ -ATPase from proximal tubule cells in both groups and normalized the systolic blood pressure in RBD without effect in CTRL rats. We conclude that chronic undernutrition modifies the response of blood pressure and metabolic responses to rostafuroxin.
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Affiliation(s)
- Amaury Pereira‐Acácio
- Graduate Program of Translational Biomedicine/BIOTRANSUniversity of Grande RioDuque de CaxiasBrazil
- Carlos Chagas Filho Institute of BiophysicsFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Center for Structural Biology and Bioimaging/CENABIOFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Institute of Science and Technology for Regenerative Medicine/REGENERARio de JaneiroBrazil
| | - João P. M. Veloso‐Santos
- Carlos Chagas Filho Institute of BiophysicsFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Center for Structural Biology and Bioimaging/CENABIOFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Institute of Science and Technology for Regenerative Medicine/REGENERARio de JaneiroBrazil
| | - Danilo Alves‐Bezerra
- Graduate Program of Translational Biomedicine/BIOTRANSUniversity of Grande RioDuque de CaxiasBrazil
- National Center for Structural Biology and Bioimaging/CENABIOFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Institute of Science and Technology for Regenerative Medicine/REGENERARio de JaneiroBrazil
| | - Glória Costa‐Sarmento
- Carlos Chagas Filho Institute of BiophysicsFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Center for Structural Biology and Bioimaging/CENABIOFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Institute of Science and Technology for Regenerative Medicine/REGENERARio de JaneiroBrazil
| | - Humberto Muzi‐Filho
- Carlos Chagas Filho Institute of BiophysicsFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Center for Structural Biology and Bioimaging/CENABIOFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Institute of Science and Technology for Regenerative Medicine/REGENERARio de JaneiroBrazil
| | - Adalberto Vieyra
- Graduate Program of Translational Biomedicine/BIOTRANSUniversity of Grande RioDuque de CaxiasBrazil
- Carlos Chagas Filho Institute of BiophysicsFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Center for Structural Biology and Bioimaging/CENABIOFederal University of Rio de JaneiroRio de JaneiroBrazil
- National Institute of Science and Technology for Regenerative Medicine/REGENERARio de JaneiroBrazil
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7
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Wang T, Liu T, Xu S, Frindt G, Weinstein AM, Palmer LG. High dietary K + intake inhibits proximal tubule transport. Am J Physiol Renal Physiol 2023; 325:F224-F234. [PMID: 37318989 PMCID: PMC10396284 DOI: 10.1152/ajprenal.00013.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/15/2023] [Accepted: 06/14/2023] [Indexed: 06/17/2023] Open
Abstract
The impact of chronic dietary K+ loading on proximal tubule (PT) function was measured using free-flow micropuncture along with measurements of overall kidney function, including urine volume, glomerular filtration rate, and absolute and fractional Na+ and K+ excretion in the rat. Feeding animals a diet with 5% KCl [high K+ (HK)] for 7 days reduced glomerular filtration rate by 29%, increased urine volume by 77%, and increased absolute K+ excretion by 202% compared with rats on a 1% KCl [control K+ (CK)] diet. HK did not change absolute Na+ excretion but significantly increased fraction excretion of Na+ (1.40% vs. 0.64%), indicating that fractional Na+ absorption is reduced by HK. PT reabsorption was assessed using free-flow micropuncture in anesthetized animals. At 80% of the accessible length of the PT, measurements of inulin concentration indicated volume reabsorption of 73% and 54% in CK and HK, respectively. At the same site, fractional PT Na+ reabsorption was 66% in CK animals and 37% in HK animals. Fractional PT K+ reabsorption was 66% in CK and 37% in HK. To assess the role of Na+/H+ exchanger isoform 3 (NHE3) in mediating these changes, we measured NHE3 protein expression in total kidney microsomes as well as surface membranes using Western blots. We found no significant changes in protein in either cell fraction. Expression of the Ser552 phosphorylated form of NHE3 was also similar in CK and HK animals. Reduction in PT transport may facilitate K+ excretion and help balance Na+ excretion by shifting Na+ reabsorption from K+-reabsorbing to K+-secreting nephron segments.NEW & NOTEWORTHY In rats fed a diet rich in K+, proximal tubules reabsorbed less fluid, Na+, and K+ compared with those in animals on a control diet. Glomerular filtration rates also decreased, probably due to glomerulotubular feedback. These reductions may help to maintain balance of the two ions simultaneously by shifting Na+ reabsorption to K+-secreting nephron segments.
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Affiliation(s)
- Tong Wang
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Tommy Liu
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Shuhua Xu
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Gustavo Frindt
- Department of Physiology and Biophysics, Weill-Cornell Medicine, New York, New York, United States
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weill-Cornell Medicine, New York, New York, United States
| | - Lawrence G Palmer
- Department of Physiology and Biophysics, Weill-Cornell Medicine, New York, New York, United States
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8
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Mukherji ST, Brambilla L, Stuart KB, Mayes I, Kutz LC, Chen Y, Barbosa LA, Elmadbouh I, McDermott JP, Haller ST, Romero MF, Soleimani M, Liu J, Shapiro JI, Blanco GV, Xie Z, Pierre SV. Na/K-ATPase signaling tonically inhibits sodium reabsorption in the renal proximal tubule. FASEB J 2023; 37:e22835. [PMID: 36856735 PMCID: PMC10028530 DOI: 10.1096/fj.202200785rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 03/02/2023]
Abstract
Through its classic ATP-dependent ion-pumping function, basolateral Na/K-ATPase (NKA) generates the Na+ gradient that drives apical Na+ reabsorption in the renal proximal tubule (RPT), primarily through the Na+ /H+ exchanger (NHE3). Accordingly, activation of NKA-mediated ion transport decreases natriuresis through activation of basolateral (NKA) and apical (NHE3) Na+ reabsorption. In contrast, activation of the more recently discovered NKA signaling function triggers cellular redistribution of RPT NKA and NHE3 and decreases Na+ reabsorption. We used gene targeting to test the respective contributions of NKA signaling and ion pumping to the overall regulation of RPT Na+ reabsorption. Knockdown of RPT NKA in cells and mice increased membrane NHE3 and Na+ /HCO3 - cotransporter (NBCe1A). Urine output and absolute Na+ excretion decreased by 65%, driven by increased RPT Na+ reabsorption (as indicated by decreased lithium clearance and unchanged glomerular filtration rate), and accompanied by elevated blood pressure. This hyper reabsorptive phenotype was rescued upon crossing with RPT NHE3-/- mice, confirming the importance of NKA/NHE3 coupling. Hence, NKA signaling exerts a tonic inhibition on Na+ reabsorption by regulating key apical and basolateral Na+ transporters. This action, lifted upon NKA genetic suppression, tonically counteracts NKA's ATP-driven function of basolateral Na+ reabsorption. Strikingly, NKA signaling is not only physiologically relevant but it also appears to be functionally dominant over NKA ion pumping in the control of RPT reabsorption.
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Affiliation(s)
- Shreya T. Mukherji
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
| | - Luca Brambilla
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
| | - Kailey B. Stuart
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
| | - Isabella Mayes
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
| | - Laura C. Kutz
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
| | - Yiliang Chen
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Blood Research Institute, Versiti, WI
| | - Leandro A Barbosa
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
- Universidade Federal de São João del-Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil
| | - Ibrahim Elmadbouh
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
| | - Jeff P. McDermott
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS
| | - Steven T. Haller
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH
| | - Michael F. Romero
- Physiology & Biomedical Engineering and Nephrology & Hypertension, Mayo Clinic College of Medicine & Science, Rochester, MN
| | - Manoocher Soleimani
- Department of Medicine, The University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Jiang Liu
- Joan C. Edwards School of Medicine, Marshall University, Huntington, WV
| | - Joseph I. Shapiro
- Joan C. Edwards School of Medicine, Marshall University, Huntington, WV
| | - Gustavo V. Blanco
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
| | - Sandrine V. Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV
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9
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Just A, Mallmann RT, Grossmann S, Sleman F, Klugbauer N. Two-pore channel protein TPC1 is a determining factor for the adaptation of proximal tubular phosphate handling. Acta Physiol (Oxf) 2023; 237:e13914. [PMID: 36599408 DOI: 10.1111/apha.13914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/27/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Abstract
AIM Two-pore channels (TPCs) constitute a small family of cation channels expressed in endo-lysosomal compartments. TPCs have been characterized as critical elements controlling Ca2+ -mediated vesicular membrane fusion and thereby regulating endo-lysosomal vesicle trafficking. Exo- and endocytotic trafficking and lysosomal degradation are major mechanisms of adaption of epithelial transport. A prime example of highly regulated epithelial transport is the tubular system of the kidney. We therefore studied the localization of TPC protein 1 (TPC1) in the kidney and its functional role in the dynamic regulation of tubular transport. METHODS Immunohistochemistry in combination with tubular markers were used to investigate TPC1 expression in proximal and distal tubules. The excretion of phosphate and ammonium, as well as urine volume and pH were studied in vivo, in response to dynamic challenges induced by bolus injection of parathyroid hormone or acid-base transitions via consecutive infusion of NaCl, Na2 CO3 , and NH4 Cl. RESULTS In TPC1-deficient mice, the PTH-induced rise in phosphate excretion was prolonged and exaggerated, and its recovery delayed in comparison with wildtype littermates. In the acid-base transition experiment, TPC1-deficient mice showed an identical rise in phosphate excretion in response to Na2 CO3 compared with wildtypes, but a delayed NH4Cl-induced recovery. Ammonium-excretion decreased with Na2 CO3 , and increased with NH4 Cl, but without differences between genotypes. CONCLUSIONS We conclude that TPC1 is expressed subapically in the proximal but not distal tubule and plays an important role in the dynamic adaptation of proximal tubular phosphate reabsorption towards enhanced, but not reduced absorption.
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Affiliation(s)
- Armin Just
- Institut für Physiologie I, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Robert T Mallmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Sonja Grossmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Faten Sleman
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Norbert Klugbauer
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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10
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Renal sympathetic activity: A key modulator of pressure natriuresis in hypertension. Biochem Pharmacol 2023; 208:115386. [PMID: 36535529 DOI: 10.1016/j.bcp.2022.115386] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/11/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Hypertension is a complex disorder ensuing necessarily from alterations in the pressure-natriuresis relationship, the main determinant of long-term control of blood pressure. This mechanism sets natriuresis to the level of blood pressure, so that increasing pressure translates into higher osmotically driven diuresis to reduce volemia and control blood pressure. External factors affecting the renal handling of sodium regulate the pressure-natriuresis relationship so that more or less natriuresis is attained for each level of blood pressure. Hypertension can thus only develop following primary alterations in the pressure to natriuresis balance, or by abnormal activity of the regulation network. On the other hand, increased sympathetic tone is a very frequent finding in most forms of hypertension, long regarded as a key element in the pathophysiological scenario. In this article, we critically analyze the interplay of the renal component of the sympathetic nervous system and the pressure-natriuresis mechanism in the development of hypertension. A special focus is placed on discussing recent findings supporting a role of baroreceptors as a component, along with the afference of reno-renal reflex, of the input to the nucleus tractus solitarius, the central structure governing the long-term regulation of renal sympathetic efferent tone.
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11
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Pontes RB, Nishi EE, Crajoinas RO, Milanez MIO, Girardi ACC, Campos RR, Bergamaschi CT. Relative Contribution of Blood Pressure and Renal Sympathetic Nerve Activity to Proximal Tubular Sodium Reabsorption via NHE3 Activity. Int J Mol Sci 2022; 24:ijms24010349. [PMID: 36613793 PMCID: PMC9820392 DOI: 10.3390/ijms24010349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/17/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
We examined the effects of an acute increase in blood pressure (BP) and renal sympathetic nerve activity (rSNA) induced by bicuculline (Bic) injection in the paraventricular nucleus of hypothalamus (PVN) or the effects of a selective increase in rSNA induced by renal nerve stimulation (RNS) on the renal excretion of sodium and water and its effect on sodium-hydrogen exchanger 3 (NHE3) activity. Uninephrectomized anesthetized male Wistar rats were divided into three groups: (1) Sham; (2) Bic PVN: (3) RNS + Bic injection into the PVN. BP and rSNA were recorded, and urine was collected prior and after the interventions in all groups. RNS decreased sodium (58%) and water excretion (53%) independently of BP changes (p < 0.05). However, after Bic injection in the PVN during RNS stimulation, the BP and rSNA increased by 30% and 60% (p < 0.05), respectively, diuresis (5-fold) and natriuresis (2.3-fold) were increased (p < 0.05), and NHE3 activity was significantly reduced, independently of glomerular filtration rate changes. Thus, an acute increase in the BP overcomes RNS, leading to diuresis, natriuresis, and NHE3 activity inhibition.
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Affiliation(s)
- Roberto B. Pontes
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, Brazil
| | - Erika E. Nishi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, Brazil
| | - Renato O. Crajoinas
- Heart Institute (InCor), University of São Paulo Medical School, São Paulo 01246-903, Brazil
| | - Maycon I. O. Milanez
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, Brazil
| | - Adriana C. C. Girardi
- Heart Institute (InCor), University of São Paulo Medical School, São Paulo 01246-903, Brazil
| | - Ruy R Campos
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, Brazil
| | - Cassia T Bergamaschi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, Brazil
- Correspondence:
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12
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Yaribeygi H, Maleki M, Butler AE, Jamialahmadi T, Sahebkar A. New insights into cellular links between sodium-glucose cotransporter-2 inhibitors and ketogenesis. J Cell Biochem 2022; 123:1879-1890. [PMID: 36153819 DOI: 10.1002/jcb.30327] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 12/24/2022]
Abstract
Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are a newly developed class of highly effective antidiabetic therapies that normalize hyperglycemia via urinary glucose excretion. However, they may be accompanied by certain side effects that negatively impact their therapeutic benefits. SGLT2is induce a metabolic shift from glucose to fatty acids and thus increase lipolysis which, in turn, induces ketogenesis. The complete pathways linking SGLT2is to ketoacidosis have not yet been fully elucidated, though much is now known. Therefore, in this mechanistic study, we present the current knowledge and shed light upon the possible cellular pathways involved. A deeper understanding of the possible links between SGLT2is and ketogenesis could help to prevent adverse side effects in diabetic patients treated with these drugs.
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Affiliation(s)
- Habib Yaribeygi
- Research Center of Physiology, Semnan University of Medical Sciences, Semnan, Iran
| | - Mina Maleki
- Urology and Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Alexandra E Butler
- Research Department, Royal College of Surgeons in Ireland Bahrain, Adliya, Bahrain
| | - Tannaz Jamialahmadi
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,School of Medicine, The University of Western Australia, Perth, Australia.,Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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13
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Noroozbabaee L, Blanco PJ, Safaei S, Nickerson DP. A modular and reusable model of epithelial transport in the proximal convoluted tubule. PLoS One 2022; 17:e0275837. [PMID: 36355848 PMCID: PMC9648790 DOI: 10.1371/journal.pone.0275837] [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: 01/16/2022] [Accepted: 09/24/2022] [Indexed: 11/12/2022] Open
Abstract
We review a collection of published renal epithelial transport models, from which we build a consistent and reusable mathematical model able to reproduce many observations and predictions from the literature. The flexible modular model we present here can be adapted to specific configurations of epithelial transport, and in this work we focus on transport in the proximal convoluted tubule of the renal nephron. Our mathematical model of the epithelial proximal convoluted tubule describes the cellular and subcellular mechanisms of the transporters, intracellular buffering, solute fluxes, and other processes. We provide free and open access to the Python implementation to ensure our multiscale proximal tubule model is accessible; enabling the reader to explore the model through setting their own simulations, reproducibility tests, and sensitivity analyses.
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Affiliation(s)
- Leyla Noroozbabaee
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Pablo J. Blanco
- National Laboratory for Scientific Computing, Petrópolis, Brazil
| | - Soroush Safaei
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - David P. Nickerson
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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14
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Mohiuddin N, Frinak S, Yee J. Sodium-based osmotherapy for hyponatremia in acute decompensated heart failure. Heart Fail Rev 2021; 27:379-391. [PMID: 34767112 DOI: 10.1007/s10741-021-10124-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/25/2021] [Indexed: 10/19/2022]
Abstract
Acute decompensated heart failure (ADHF) accounts for more than 1 million hospital admissions annually and is associated with high morbidity and mortality. Decongestion with removal of increased total body sodium and total body water are goals of treatment. Acute kidney injury (AKI) or chronic kidney disease (CKD) is present in two-thirds of patients with ADHF. The pathophysiology of ADHF and AKI is bidirectional and synergistic. AKI and CKD complicate the management of ADHF by decreasing diuretic efficiency and excretion of sodium and water. Among patients hospitalized with ADHF, hyponatremia is the most common electrolyte abnormality and is classically encountered with volume overload. ADHF represents an additional therapeutic challenge particularly when oligoanuria is present. Predilution continuous venovenous hemofiltration with sodium-based osmotherapy can safely increase plasma sodium concentration without deleteriously increasing total body sodium. We present a detailed methodology that addresses the issue of hypervolemic hyponatremia in patients with ADHF and AKI.
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Affiliation(s)
- Naushaba Mohiuddin
- Division of Nephrology and Hypertension, 2799 West Grand Blvd, CFP-510, Detroit, MI, 48202, USA
| | - Stanley Frinak
- Division of Nephrology and Hypertension, 2799 West Grand Blvd, CFP-510, Detroit, MI, 48202, USA
| | - Jerry Yee
- Division of Nephrology and Hypertension, 2799 West Grand Blvd, CFP-514, Detroit, MI, 48202, USA.
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15
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Vormann MK, Tool LM, Ohbuchi M, Gijzen L, van Vught R, Hankemeier T, Kiyonaga F, Kawabe T, Goto T, Fujimori A, Vulto P, Lanz HL, Tetsuka K. Modelling and Prevention of Acute Kidney Injury through Ischemia and Reperfusion in a Combined Human Renal Proximal Tubule/Blood Vessel-on-a-Chip. KIDNEY360 2021; 3:217-231. [PMID: 35373131 PMCID: PMC8967632 DOI: 10.34067/kid.0003622021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 10/29/2021] [Indexed: 01/10/2023]
Abstract
Background Renal ischemia/reperfusion injury (rIRI) is one of the major causes of AKI. Although animal models are suitable for investigating systemic symptoms of AKI, they are limited in translatability. Human in vitro models are crucial in giving mechanistic insights into rIRI; however, they miss out on crucial aspects such as reperfusion injury and the multitissue aspect of AKI. Methods We advanced the current renal proximal tubule-on-a-chip model to a coculture model with a perfused endothelial vessel separated by an extracellular matrix. The coculture was characterized for its three-dimensional structure, protein expression, and response to nephrotoxins. Then, rIRI was captured through control of oxygen levels, nutrient availability, and perfusion flow settings. Injury was quantified through morphologic assessment, caspase-3/7 activation, and cell viability. Results The combination of low oxygen, reduced glucose, and interrupted flow was potent to disturb the proximal tubules. This effect was strongly amplified upon reperfusion. Endothelial vessels were less sensitive to the ischemia-reperfusion parameters. Adenosine treatment showed a protective effect on the disruption of the epithelium and on the caspase-3/7 activation. Conclusions A human in vitro rIRI model was developed using a coculture of a proximal tubule and blood vessel on-a-chip, which was used to characterize the renoprotective effect of adenosine. The robustness of the model and assays in combination with the throughput of the platform make it ideal to advance pathophysiological research and enable the development of novel therapeutic modalities.
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Affiliation(s)
| | | | - Masato Ohbuchi
- Analysis and Pharmacokinetics Research Labs, Astellas Pharma, Inc., Ibaraki, Japan
| | | | | | | | - Fumiko Kiyonaga
- Innovation and Incubation Research Labs, Astellas Pharma, Inc., Ibaraki, Japan
| | | | - Takayuki Goto
- Modality Research Labs, Astellas Pharma, Inc., Ibaraki, Japan
| | - Akira Fujimori
- Research Portfolio Planning, Astellas Pharma, Inc., Ibaraki, Japan
| | | | | | - Kazuhiro Tetsuka
- Analysis and Pharmacokinetics Research Labs, Astellas Pharma, Inc., Ibaraki, Japan
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16
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Mehmood HR, Khan Z, Jahangir HMS, Hussain A, Elahi A, Askari SMH. Assessment of serum biochemical derangements and associated risk factors of chronic kidney disease. J Taibah Univ Med Sci 2021; 17:376-383. [PMID: 35722231 PMCID: PMC9170744 DOI: 10.1016/j.jtumed.2021.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/23/2021] [Accepted: 09/04/2021] [Indexed: 12/03/2022] Open
Abstract
Objective Chronic kidney disease and/or disturbance in renal excretory function may lead to nitrogenous waste collection beyond the term as well as derangements of several serum biochemicals. There is no previous study from Pakistan that reveals serum electrolyte derangements in confirmed chronic kidney disease (CKD) patients and other biochemicals associated with CKD. This study aims to examine the derangements of serum biochemicals and the association of several risk factors with CKD. Methods The study enrolled 612 confirmed CKD patients with a glomerular filtration rate (GFR) < 15 ml/min that were treated as a part of the integrated care programme at Mayo Hospital Lahore (one of the largest hospitals in Pakistan). Serum biochemicals were estimated on AU 680 (Beckman Coulter) using the spectrophotometric technique. Results All the CKD patients had elevated creatinine and urea levels, but only 63.4% were suffering from hyperuricemia. The incidence of diabetes and malnutrition assessed by serum albumin (hypoalbuminemia) was 27.4% and 72%, respectively. Among electrolyte disorders, hyperphosphatemia (71.8%) and hypocalcaemia (61.9%) were found to be more prevalent. Furthermore, gender, malnutrition, diabetes, hyperuricemia, and phosphorus and magnesium derangements were found to be statistically significant risk factors for CKD, whereas malnutrition and magnesium derangement were associated with hyperuricemia. Conclusion It is imperative to improve dietary protein and monitor serum electrolyte concentration in renal dysfunction patients to slow the progression of CKD to end-stage renal disease (ESRD) and other serious complications.
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17
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Li XC, Wang CH, Leite APO, Zhuo JL. Intratubular, Intracellular, and Mitochondrial Angiotensin II/AT 1 (AT1a) Receptor/NHE3 Signaling Plays a Critical Role in Angiotensin II-Induced Hypertension and Kidney Injury. Front Physiol 2021; 12:702797. [PMID: 34408663 PMCID: PMC8364949 DOI: 10.3389/fphys.2021.702797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 05/24/2021] [Indexed: 12/14/2022] Open
Abstract
Hypertension is well recognized to be the most important risk factor for cardiovascular diseases, stroke, and end-stage kidney failure. A quarter of the world’s adult populations and 46% of the US adults develop hypertension and currently require antihypertensive treatments. Only 50% of hypertensive patients are responsive to current antihypertensive drugs, whereas remaining patients may continue to develop cardiovascular, stroke, and kidney diseases. The mechanisms underlying the poorly controlled hypertension remain incompletely understood. Recently, we have focused our efforts to uncover additional renal mechanisms, pathways, and therapeutic targets of poorly controlled hypertension and target organ injury using novel animal models or innovative experimental approaches. Specifically, we studied and elucidated the important roles of intratubular, intracellular, and mitochondrial angiotensin II (Ang II) system in the development of Ang II-dependent hypertension. The objectives of this invited article are to review and discuss our recent findings that (a) circulating and intratubular Ang II is taken up by the proximal tubules via the (AT1) AT1a receptor-dependent mechanism, (b) intracellular administration of Ang II in proximal tubule cells or adenovirus-mediated overexpression of an intracellular Ang II fusion protein selectively in the mitochonria of the proximal tubules induces blood pressure responses, and (c) genetic deletion of AT1 (AT1a) receptors or the Na+/H+ exchanger 3 selectively in the proximal tubules decreases basal blood pressure and attenuates Ang II-induced hypertension. These studies provide a new perspective into the important roles of the intratubular, intracellular, and mitochondrial angiotensin II/AT1 (AT1a) receptor signaling in Ang II-dependent hypertensive kidney diseases.
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Affiliation(s)
- Xiao Chun Li
- Tulane Hypertension and Renal Center of Excellence, Department of Physiology, Tulane University School of Medicine,New Orleans, LA, United States
| | - Chih-Hong Wang
- Tulane Hypertension and Renal Center of Excellence, Department of Physiology, Tulane University School of Medicine,New Orleans, LA, United States
| | - Ana Paula Oliveira Leite
- Tulane Hypertension and Renal Center of Excellence, Department of Physiology, Tulane University School of Medicine,New Orleans, LA, United States
| | - Jia Long Zhuo
- Tulane Hypertension and Renal Center of Excellence, Department of Physiology, Tulane University School of Medicine,New Orleans, LA, United States
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18
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Nox4 Maintains Blood Pressure during Low Sodium Diet. Antioxidants (Basel) 2021; 10:antiox10071103. [PMID: 34356336 PMCID: PMC8301203 DOI: 10.3390/antiox10071103] [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: 06/02/2021] [Revised: 07/02/2021] [Accepted: 07/06/2021] [Indexed: 01/26/2023] Open
Abstract
The NADPH oxidase Nox4 is a hydrogen peroxide (H2O2)-producing enzyme, with the highest expression in the kidney. As the kidney is involved in volume and blood pressure control through sodium handling, we set out to determine the impact of a low sodium diet on these parameters in WT and Nox4-/- mice. Nox4 expression in the murine kidney was restricted to the proximal tubule. Nevertheless, low-sodium-induced weight loss and sodium sparing function was similar in WT and Nox4-/- mice, disputing an important function of renal Nox4 in sodium handling. In contrast, a low sodium diet resulted in a reduction in systolic blood pressure in Nox4-/- as compared to WT mice. This was associated with a selectively lower pressure to heart-rate ratio, as well as heart to body weight ratio. In general, a low sodium diet leads to activation of sympathetic tone and the renin angiotensin system, which subsequently increases peripheral resistance. Our observations suggest that the control by this system is attenuated in Nox4-/- mice, resulting in lower blood pressure in response to low sodium.
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Abstract
TRPC3 is a Ca2+-permeable cation channel commonly activated by the G-protein coupled receptors (GPCR) and mechanical distortion of the plasma membrane. TRPC3-mediated Ca2+ influx has been implicated in a variety of signaling processes in both excitable and non-excitable cells. Kidneys play a commanding role in maintaining whole-body homeostasis and setting blood pressure. TRPC3 is expressed abundantly in the renal vasculature and in epithelial cells, where it is well positioned to mediate signaling and transport functions in response to GPCR-dependent endocrine stimuli. In addition, TRPC3 could be activated by mechanical forces resulting from dynamic changes in the renal tubule fluid flow and osmolarity. This review critically analyzes the available published evidence of the physiological roles of TRPC3 in different parts of the kidney and describes the pathophysiological ramifications of TRPC3 ablation. We also speculate how this evidence could be further translated into the clinic.
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Affiliation(s)
- Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, TX, USA
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New Insights into the Critical Importance of Intratubular Na +/H + Exchanger 3 and Its Potential Therapeutic Implications in Hypertension. Curr Hypertens Rep 2021; 23:34. [PMID: 34110521 DOI: 10.1007/s11906-021-01152-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2021] [Indexed: 01/08/2023]
Abstract
PURPOSE OF REVIEW The sodium (Na+) and hydrogen (H+) exchanger 3 (NHE3), known as solute carrier family 9 member 3 (SLC9A3), mediates active transcellular Na+ and bicarbonate reabsorption in the small intestine of the gut and proximal tubules of the kidney. The purpose of this article is to review and discuss recent findings on the critical roles of intestinal and proximal tubule NHE3 in maintaining basal blood pressure (BP) homeostasis and their potential therapeutic implications in the development of angiotensin II (Ang II)-dependent hypertension. RECENT FINDINGS Recently, our and other laboratories have generated or used novel genetically modified mouse models with whole-body, kidney-specific, or proximal tubule-specific deletion of NHE3 to determine the critical roles and underlying mechanisms of NHE3 in maintaining basal BP homeostasis and the development of Ang II-induced hypertension at the whole-body, kidney, or proximal tubule levels. The new findings demonstrate that NHE3 contributes to about 10 to 15 mmHg to basal blood pressure levels, and that deletion of NHE3 at the whole-kidney or proximal tubule level, or pharmacological inhibition of NHE3 at the kidney level with an orally absorbable NHE3 inhibitor AVE-0657, attenuates ~ 50% of Ang II-induced hypertension in mice. The results support the proof-of-concept hypothesis that NHE3 plays critical roles in physiologically maintaining normal BP and in the development of Ang II-dependent hypertension. Our results also strongly suggest that NHE3 in the proximal tubules of the kidney may be therapeutically targeted to treat poorly controlled hypertension in humans.
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Rodrigues NG, Albuquerque JAFD, Guio BM, Reis MS. Avaliação da modulação autonômica da frequência cardíaca de pacientes com doença renal crônica em hemodiálise: estudo preliminar. FISIOTERAPIA E PESQUISA 2021. [DOI: 10.1590/1809-2950/20001828022021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RESUMO A doença renal crônica (DRC) é definida como dano à função renal. Doentes renais crônicos atingem alta prevalência de morte por eventos cardiovasculares antes dos estágios finais, sendo maior a mortalidade em estágio dialítico, em que é evidenciado um desequilíbrio autonômico. Objetivamos avaliar a modulação simpatovagal de pacientes com DRC em tratamento de hemodiálise ambulatorial. Foram avaliados 23 pacientes, divididos em: Grupo DRC com DRC no estágio 5D (DRC-5D) em tratamento regular de hemodiálise ambulatorial; Grupo-controle com indivíduos saudáveis. A variabilidade da frequência cardíaca (VFC) foi coletada por um cardiofrequencímetro e analisada por índices lineares do domínio do tempo e do domínio da frequência. 14 pacientes no Grupo DRC com média de idade 48±16; e 9 pacientes saudáveis no Grupo-controle com média de idade 64±5. Nos resultados pelo domínio de tempo, o Grupo DRC mostrou valores significativamente maiores da frequência cardíaca (FC) comparado ao Grupo-controle (83,49±13,09 bpm vs. 67,88±9,43 bpm). Todavia, os índices média dos intervalos R-R (735,82±121,54 ms vs. 898,94±123,58 ms), RMSSD (11,75±11,86 ms vs. 20,03±6,80 ms), SDNN (17,06±9,81ms vs. 28,42±7,62 ms) do Grupo DRC mostraram valores significativamente menores comparados aos do Grupo-controle, respectivamente. Nos resultados pelo domínio da frequência, o Grupo DRC mostrou valores significativamente menores em comparação ao Grupo-controle nos índices BFab (129,7±184,3 ms vs. 262,31±168,15 ms) e AFab (82,70±227,66 ms vs. 180,77±119,85 ms). Pacientes com DRC em hemodiálise apresentaram redução da modulação parassimpática quando comparados com indivíduos saudáveis, sugerindo prejuízo do balanço simpatovagal e, consequente, disfunção autonômica cardíaca.
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Dwivedi M, Shaw A. Implication of cation-proton antiporters (CPA) in human health and diseases causing microorganisms. Biochimie 2021; 182:85-98. [PMID: 33453344 DOI: 10.1016/j.biochi.2021.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 01/03/2021] [Accepted: 01/07/2021] [Indexed: 12/15/2022]
Abstract
Cation and protons perform a substantial role in all the organism and its homeostasis within the cells are maintained by the cation-proton antiporters (CPAs). CPA is the huge family of the membrane transporter protein throughout the plant and animal kingdom including microorganism. In human, any malfunctioning of these proteins may lead to severe diseases like hypertension, heart diseases etc and CPAs are recently proposed to be responsible for the virulent property of various pathogens including Vibrio cholerae, Yersinia pestis etc. Human Sodium-Proton exchangers (Na+/H+ exchangers, NHEs) are crucial in ion homeostasis whereas Ec-NhaA, Na + -H + Antiporters maintain a balance of Na+ and proton in E. coli, regulating pH and cell volume within the cell. These Sodium-Proton antiporters are found to be responsible for the virulence in various pathogens causing human diseases. Understanding of these CPAs may assist investigators to target such human diseases, that further may lead to establishing the effective path for therapeutics or drug designing against associated human disease. Here we have compiled all such information on CPAs and provide a systematic approach to unravel the mechanism and role of antiporter proteins in a wide range of organisms. Being involved throughout all the species, this review on cation-proton antiporters may attract the attention of many investigators and concerned researchers and will be provided with the recent detailed information on the role of CPA in human health.
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Affiliation(s)
- Manish Dwivedi
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India.
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Hering L, Rahman M, Potthoff SA, Rump LC, Stegbauer J. Role of α2-Adrenoceptors in Hypertension: Focus on Renal Sympathetic Neurotransmitter Release, Inflammation, and Sodium Homeostasis. Front Physiol 2020; 11:566871. [PMID: 33240096 PMCID: PMC7680782 DOI: 10.3389/fphys.2020.566871] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/19/2020] [Indexed: 12/19/2022] Open
Abstract
The kidney is extensively innervated by sympathetic nerves playing an important role in the regulation of blood pressure homeostasis. Sympathetic nerve activity is ultimately controlled by the central nervous system (CNS). Norepinephrine, the main sympathetic neurotransmitter, is released at prejunctional neuroeffector junctions in the kidney and modulates renin release, renal vascular resistance, sodium and water handling, and immune cell response. Under physiological conditions, renal sympathetic nerve activity (RSNA) is modulated by peripheral mechanisms such as the renorenal reflex, a complex interaction between efferent sympathetic nerves, central mechanism, and afferent sensory nerves. RSNA is increased in hypertension and, therefore, critical for the perpetuation of hypertension and the development of hypertensive kidney disease. Renal sympathetic neurotransmission is not only regulated by RSNA but also by prejunctional α2-adrenoceptors. Prejunctional α2-adrenoceptors serve as autoreceptors which, when activated by norepinephrine, inhibit the subsequent release of norepinephrine induced by a sympathetic nerve impulse. Deletion of α2-adrenoceptors aggravates hypertension ultimately by modulating renal pressor response and sodium handling. α2-adrenoceptors are also expressed in the vasculature, renal tubules, and immune cells and exert thereby effects related to vascular tone, sodium excretion, and inflammation. In the present review, we highlight the role of α2-adrenoceptors on renal sympathetic neurotransmission and its impact on hypertension. Moreover, we focus on physiological and pathophysiological functions mediated by non-adrenergic α2-adrenoceptors. In detail, we discuss the effects of sympathetic norepinephrine release and α2-adrenoceptor activation on renal sodium transporters, on renal vascular tone, and on immune cells in the context of hypertension and kidney disease.
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Affiliation(s)
- Lydia Hering
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Masudur Rahman
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sebastian A Potthoff
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Lars C Rump
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Johannes Stegbauer
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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ELABELA attenuates deoxycorticosterone acetate/salt-induced hypertension and renal injury by inhibition of NADPH oxidase/ROS/NLRP3 inflammasome pathway. Cell Death Dis 2020; 11:698. [PMID: 32829380 PMCID: PMC7443189 DOI: 10.1038/s41419-020-02912-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 08/05/2020] [Accepted: 08/05/2020] [Indexed: 12/15/2022]
Abstract
ELABELA (ELA), a 32-residue hormone peptide abundantly expressed in adult kidneys, has been identified as a novel endogenous ligand for APJ/Apelin receptor. The aim of this study was to investigate the role of ELA in deoxycorticosterone acetate (DOCA)/salt-induced hypertension and further explore the underlying mechanism. In DOCA/salt-treated rats, the mRNA level of ELA greatly decreased in the renal medulla. Next, overexpression of ELA in the kidney was found to attenuate DOCA/salt-induced hypertension and renal injury, including lower blood pressure, reversed glomerular morphological damage, decreased blood urea nitrogen (BUN), and blocked the accumulation of fibrotic markers. Mechanistically, ELA overexpression inhibited renal nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and subsequent reactive oxygen species (ROS) production, thus resulted in the blockade of formation and activation of Nod-like receptor protein 3 (NLRP3) inflammasome. The inhibitory effects of ELA on Aldosterone-stimulated NADPH oxidase/ROS/NLRP3 inflammasome pathway were confirmed in the human renal tubular cells. Furthermore, our in vivo and in vitro results showed that the deficiency of the apelin receptor APJ did not influence the antihypertensive effect and blockage to NADPH oxidase/ROS/NLRP3 pathway of ELA. Moreover, in heterozygous ELA knockout mice (ELA+/−), the ELA deficiency remarkably accelerated the onset of DOCA/salt-induced hypertension. Our data demonstrate that ELA prevents DOCA/salt-induced hypertension by inhibiting NADPH oxidase/ROS/NLRP3 pathway in the kidney, which is APJ independent. Pharmacological targeting of ELA may serve as a novel therapeutic strategy for the treatment of hypertensive kidney disease.
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Hu R, McDonough AA, Layton AT. Sex differences in solute transport along the nephrons: effects of Na + transport inhibition. Am J Physiol Renal Physiol 2020; 319:F487-F505. [PMID: 32744084 DOI: 10.1152/ajprenal.00240.2020] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Each day, ~1.7 kg of NaCl and 180 liters of water are reabsorbed by nephron segments in humans, with urinary excretion fine tuned to meet homeostatic requirements. These tasks are coordinated by a spectrum of renal Na+ transporters and channels. The goal of the present study was to investigate the extent to which inhibitors of transepithelial Na+ transport (TNa) along the nephron alter urinary solute excretion and how those effects may vary between male and female subjects. To accomplish that goal, we developed sex-specific multinephron models that represent detailed transcellular and paracellular transport processes along the nephrons of male and female rat kidneys. We simulated inhibition of Na+/H+ exchanger 3 (NHE3), bumetanide-sensitive Na+-K+-2Cl- cotransporter (NKCC2), Na+-Cl- cotransporter (NCC), and amiloride-sensitive epithelial Na+ channel (ENaC). NHE3 inhibition simulations predicted a substantially reduced proximal tubule TNa, and NKCC2 inhibition substantially reduced thick ascending limb TNa. Both gave rise to diuresis, natriuresis, and kaliuresis, with those effects stronger in female rats. While NCC inhibition was predicted to have only minor impact on renal TNa, it nonetheless had a notable effect of enhancing excretion of Na+, K+, and Cl-, particularly in female rats. Inhibition of ENaC was predicted to have opposite effects on the excretion of Na+ (increased) and K+ (decreased) and to have only a minor impact on whole kidney TNa. Unlike inhibition of other transporters, ENaC inhibition induced stronger natriuresis and diuresis in male rats than female rats. Overall, model predictions agreed well with measured changes in Na+ and K+ excretion in response to diuretics and Na+ transporter mutations.
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Affiliation(s)
- Rui Hu
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Anita T Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada.,Department of Biology, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
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26
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Yang L, Frindt G, Xu Y, Uchida S, Palmer LG. Aldosterone-dependent and -independent regulation of Na + and K + excretion and ENaC in mouse kidneys. Am J Physiol Renal Physiol 2020; 319:F323-F334. [PMID: 32628540 DOI: 10.1152/ajprenal.00204.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We investigated the regulation of Na+ and K+ excretion and the epithelial Na+ channel (ENaC) in mice lacking the gene for aldosterone synthase (AS) using clearance methods to assess excretion and electrophysiology and Western blot analysis to test for ENaC activity and processing. After 1 day of dietary Na+ restriction, AS-/- mice lost more Na+ in the urine than AS+/+ mice did. After 1 wk on this diet, both genotypes strongly reduced urinary Na+ excretion, but creatinine clearance decreased only in AS-/- mice. Only AS+/+ animals exhibited increased ENaC function, assessed as amiloride-sensitive whole cell currents in collecting ducts or cleavage of αENaC and γENaC in Western blots. To assess the role of aldosterone in the excretion of a K+ load, animals were fasted overnight and refed with high-K+ or low-K+ diets for 5 h. Both AS+/+ and AS-/- mice excreted a large amount of K+ during this period. In both phenotypes the excretion was benzamil sensitive, indicating increased K+ secretion coupled to ENaC-dependent Na+ reabsorption. However, the increase in plasma K+ under these conditions was much larger in AS-/- animals than in AS+/+ animals. In both groups, cleavage of αENaC and γENaC increased. However, Na+ current measured ex vivo in connecting tubules was enhanced only in AS+/+ mice. We conclude that in the absence of aldosterone, mice can conserve Na+ without ENaC activation but at the expense of diminished glomerular filtration rate. Excretion of a K+ load can be accomplished through aldosterone-independent upregulation of ENaC, but aldosterone is required to excrete the excess K+ without hyperkalemia.
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Affiliation(s)
- Lei Yang
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York
| | - Gustavo Frindt
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York
| | - Yuanyuan Xu
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York.,Department of Cardiology, the Fourth Hospital of Harbin Medical University, Harbin, China
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Lawrence G Palmer
- Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, New York
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27
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Gilani A, Agostinucci K, Pascale JV, Hossain S, Kandhi S, Pandey V, Garcia V, Nasjletti A, Laniado Schwartzman M. Proximal tubular-targeted overexpression of the Cyp4a12-20-HETE synthase promotes salt-sensitive hypertension in male mice. Am J Physiol Regul Integr Comp Physiol 2020; 319:R87-R95. [PMID: 32633545 PMCID: PMC7468799 DOI: 10.1152/ajpregu.00089.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/01/2020] [Accepted: 06/09/2020] [Indexed: 12/23/2022]
Abstract
20-Hydroxyeicosatetraenoic acid (20-HETE) has been linked to blood pressure (BP) regulation via actions on the renal microvasculature and tubules. We assessed tubular 20-HETE contribution to hypertension by generating transgenic mice overexpressing the CYP4A12-20-HETE synthase (PT-4a12 mice) under the control of the proximal tubule (PT)-specific promoter, phosphoenolpyruvate carboxykinase (PEPCK). 20-HETE levels in the kidney cortex of male (967±210 vs. 249±69 pg/mg protein), but not female (121±15 vs. 92±11 pg/mg protein) PT-4a12 mice, showed a 2.5-fold increase compared to WT. Renal cortical Cyp4a12 mRNA and CYP4A12 protein in male, but not female PT-4a12 mice increased by 2-3-fold compared to WT. Male PT-4a12 mice displayed elevated BP (142±1 vs. 111±4 mmHg, p<0.0001), whereas BP in females PT-4a12 mice was not significantly different from WT (118±2 vs. 117±2 mmHg; p=0.98). In male PT-4a12 mice, BP decreased when transitioned from a control salt (0.4%) to a low-salt diet (0.075%) from 135±4 to 120±6 mmHg (p<0.01) and increased to 153±5 mmHg (p<0.05) when placed on a high-salt diet (4%). Female PT-4a12 mice did not show changes in BP on either low- or high-salt diet. In conclusion, the expression of Cyp4a12 driven by the PEPCK promoter is sex-specific probably due to its X-linkage. The salt-sensitive hypertension seen in PT-4a12 male mice suggests a potential anti-natriuretic activity of 20-HETE that needs to be further explored.
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Affiliation(s)
- Ankit Gilani
- Pharmacology, New York Medical College, United States
| | | | | | - Sakib Hossain
- Pharmacology, New York Medical College, United States
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28
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Yang N, Hong NJ, Garvin JL. Dietary fructose enhances angiotensin II-stimulated Na + transport via activation of PKC-α in renal proximal tubules. Am J Physiol Renal Physiol 2020; 318:F1513-F1519. [PMID: 32390510 DOI: 10.1152/ajprenal.00543.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Angiotensin II (ANG II) stimulates proximal nephron transport via activation of classical protein kinase C (PKC) isoforms. Acute fructose treatment stimulates PKC and dietary fructose enhances ANG II's ability to stimulate Na+ transport, but the mechanisms are unclear. We hypothesized that dietary fructose enhances ANG II's ability to stimulate renal proximal tubule Na+ reabsorption by augmenting PKC-α activation and increases in intracellular Ca2+. We measured total and isoform-specific PKC activity, basal and ANG II-stimulated oxygen consumption, a surrogate of Na+ reabsorption, and intracellular Ca2+ in proximal tubules from rats given either 20% fructose in their drinking water (fructose group) or tap water (control group). Total PKC activity was measured by ELISA. PKC-α, PKC-β, and PKC-γ activities were assessed by measuring particulate-to-soluble ratios. Intracelluar Ca2+ was measured using fura 2. ANG II stimulated total PKC activity by 53 ± 15% in the fructose group but not in the control group (-15 ± 11%, P < 0.002). ANG II stimulated PKC-α by 0.134 ± 0.026 but not in the control group (-0.002 ± 0.020, P < 0.002). ANG II increased PKC-γ activity by 0.008 ± 0.003 in the fructose group but not in the control group (P < 0.046). ANG II did not stimulate PKC-β in either group. ANG II increased Na+ transport by 454 ± 87 nmol·min-1·mg protein-1 in fructose group, and the PKC-α/β inhibitor Gö6976 blocked this increase (-96 ± 205 nmol·min-1·mg protein-1, P < 0.045). ANG II increased intracellular Ca2+ by 148 ± 53 nM in the fructose group but only by 43 ± 10 nM in the control group (P < 0.035). The intracellular Ca2+ chelator BAPTA blocked the ANG II-induced increase in Na+ transport in the fructose group. We concluded that dietary fructose enhances ANG II's ability to stimulate renal proximal tubule Na+ reabsorption by augmenting PKC-α activation via elevated increases in intacellular Ca2+.
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Affiliation(s)
- Nianxin Yang
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio.,Biochemistry, Molecular, Cellular and Developmental Biology, University of California, Davis, California
| | - Nancy J Hong
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
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Hering L, Rahman M, Hoch H, Markó L, Yang G, Reil A, Yakoub M, Gupta V, Potthoff SA, Vonend O, Ralph DL, Gurley SB, McDonough AA, Rump LC, Stegbauer J. α2A-Adrenoceptors Modulate Renal Sympathetic Neurotransmission and Protect against Hypertensive Kidney Disease. J Am Soc Nephrol 2020; 31:783-798. [PMID: 32086277 DOI: 10.1681/asn.2019060599] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Increased nerve activity causes hypertension and kidney disease. Recent studies suggest that renal denervation reduces BP in patients with hypertension. Renal NE release is regulated by prejunctional α2A-adrenoceptors on sympathetic nerves, and α2A-adrenoceptors act as autoreceptors by binding endogenous NE to inhibit its own release. However, the role of α2A-adrenoceptors in the pathogenesis of hypertensive kidney disease is unknown. METHODS We investigated effects of α2A-adrenoceptor-regulated renal NE release on the development of angiotensin II-dependent hypertension and kidney disease. In uninephrectomized wild-type and α2A-adrenoceptor-knockout mice, we induced hypertensive kidney disease by infusing AngII for 28 days. RESULTS Urinary NE excretion and BP did not differ between normotensive α2A-adrenoceptor-knockout mice and wild-type mice at baseline. However, NE excretion increased during AngII treatment, with the knockout mice displaying NE levels that were significantly higher than those of wild-type mice. Accordingly, the α2A-adrenoceptor-knockout mice exhibited a systolic BP increase, which was about 40 mm Hg higher than that found in wild-type mice, and more extensive kidney damage. In isolated kidneys, AngII-enhanced renal nerve stimulation induced NE release and pressor responses to a greater extent in kidneys from α2A-adrenoceptor-knockout mice. Activation of specific sodium transporters accompanied the exaggerated hypertensive BP response in α2A-adrenoceptor-deficient kidneys. These effects depend on renal nerves, as demonstrated by reduced severity of AngII-mediated hypertension and improved kidney function observed in α2A-adrenoceptor-knockout mice after renal denervation. CONCLUSIONS Our findings reveal a protective role of prejunctional inhibitory α2A-adrenoceptors in pathophysiologic conditions with an activated renin-angiotensin system, such as hypertensive kidney disease, and support the concept of sympatholytic therapy as a treatment.
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Affiliation(s)
- Lydia Hering
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Masudur Rahman
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Henning Hoch
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Lajos Markó
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbruck Center for Molecular Medicine, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,Charité Medical Faculty Berlin, Berlin, Germany
| | - Guang Yang
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,The Shenzhen Key Laboratory of Health Sciences and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
| | - Annika Reil
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Mina Yakoub
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Vikram Gupta
- Department of Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Sebastian A Potthoff
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Oliver Vonend
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Nierenzentrum, DKD Helios Medical Center, Wiesbaden, Germany
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Susan B Gurley
- Division of Nephrology and Hypertension, School of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Lars C Rump
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Johannes Stegbauer
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany;
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Protein Abundance of Clinically Relevant Drug Transporters in The Human Kidneys. Int J Mol Sci 2019; 20:ijms20215303. [PMID: 31653114 PMCID: PMC6862022 DOI: 10.3390/ijms20215303] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
Renal drug transporters such as the organic cation transporters (OCTs), organic anion transporters (OATs) and multidrug resistance proteins (MRPs) play an important role in the tubular secretion of many drugs influencing their efficacy and safety. However, only little is known about the distinct protein abundance of these transporters in human kidneys, and about the impact of age and gender as potential factors of inter-subject variability in their expression and function. The aim of this study was to determine the protein abundance of MDR1, MRP1-4, BCRP, OAT1-3, OCT2-3, MATE1, PEPT1/2, and ORCTL2 by liquid chromatography-tandem mass spectrometry-based targeted proteomics in a set of 36 human cortex kidney samples (20 males, 16 females; median age 53 and 55 years, respectively). OAT1 and 3, OCT2 and ORCTL2 were found to be most abundant renal SLC transporters while MDR1, MRP1 and MRP4 were the dominating ABC transporters. Only the expression levels of MDR1 and ORCTL2 were significantly higher abundant in older donors. Moreover, we found several significant correlations between different transporters, which may indicate their functional interplay in renal vectorial transport processes. Our data may contribute to a better understanding of the molecular processes determining renal excretion of drugs.
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31
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Chamanza R, Naylor SW, Carreira V, Amuzie C, Ma JY, Bradley AE, Blankenship B, McDorman K, Louden C. Normal Anatomy, Histology, and Spontaneous Pathology of the Kidney, and Selected Renal Biomarker Reference Ranges in the Cynomolgus Monkey. Toxicol Pathol 2019; 47:612-633. [DOI: 10.1177/0192623319859263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
To further our understanding of the nonhuman primate kidney anatomy, histology, and incidences of spontaneous pathology, we retrospectively examined kidneys from a total of 505 control Cynomolgus monkeys ( Macaca fascicularis; 264 male and 241 females) aged 2 to 6 years, from toxicity studies. Kidney weights, urinalysis, and kidney-related clinical biochemistry parameters were also evaluated. Although the functional anatomy of the monkey kidney is relatively similar to that of other laboratory animals and humans, a few differences and species-specific peculiarities exist. Unlike humans, the macaque kidney is unipapillate, with a relatively underdeveloped papilla, scarce long loops of Henle, and a near-equivalent cortical to medullary ratio. The most common spontaneous microscopic findings were interstitial infiltrates or interstitial nephritis and other tubular lesions, but several forms of glomerulopathy that may be interpreted as drug-induced were occasionally observed. Common incidental findings of little pathological significance included: papillary mineralization, epithelial pigment, multinucleate cells, cuboidal metaplasia of the Bowman’s capsule, and urothelial inclusions. Kidney weights, and some clinical chemistry parameters, showed age- and sex-related variations. Taken together, these data will aid the toxicologic pathologist to better evaluate the nonhuman primate kidney and assess the species’ suitability as a model for identifying and characterizing drug-induced injury.
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Affiliation(s)
- Ronnie Chamanza
- Nonclinical Safety, Janssen Research & Development, Janssen Pharmaceutical Companies of Johnson & Johnson, Beerse, Belgium
| | | | - Vinicius Carreira
- Janssen Pharmaceutical Companies of Johnson & Johnson, La Jolla, CA, USA
| | - Chidozie Amuzie
- Janssen Pharmaceutical Companies of Johnson & Johnson, Spring House, PA, USA
| | - Jing Ying Ma
- Janssen Pharmaceutical Companies of Johnson & Johnson, La Jolla, CA, USA
| | | | | | | | - Calvert Louden
- Janssen Pharmaceutical Companies of Johnson & Johnson, Spring House, PA, USA
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32
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McClure ST, Rebholz CM, Medabalimi S, Hu EA, Xu Z, Selvin E, Appel LJ. Dietary phosphorus intake and blood pressure in adults: a systematic review of randomized trials and prospective observational studies. Am J Clin Nutr 2019; 109:1264-1272. [PMID: 31051505 PMCID: PMC6499505 DOI: 10.1093/ajcn/nqy343] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/31/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Elevated blood pressure (BP) is a major cause of preventable disease in the United States and around the world. It has been postulated that phosphorus intake may affect BP, with some studies suggesting a direct and others an inverse association. OBJECTIVES We systematically reviewed the literature on the association of dietary phosphorus with BP in adults and performed a qualitative synthesis. METHODS We included randomized and nonrandomized behavioral intervention and feeding studies (intervention studies) and prospective observational studies that measured dietary phosphorus intake or urinary phosphorus excretion and BP. We excluded studies of supplements, children, or individuals with major medical conditions. We searched PubMed, Embase, Cochrane Trials, and clinicaltrials.gov on 1 June, 2017 and 22 August, 2018. We assessed studies' risk of bias in their assessment of phosphorus exposure and BP. RESULTS We reviewed 4759 publications and included 14 intervention studies (2497 participants), 3 prospective observational cohorts (17,795 participants), and 2 ongoing trials. No included intervention studies were designed specifically to achieve a phosphorus contrast. Two studies found a significant positive association of dietary phosphorus with systolic BP, 4 a significant inverse association, and 8 no significant association. Four studies found a significant inverse association with diastolic BP and 10 no significant associations. Two cohorts found lower risk of incident hypertension comparing the highest with the lowest quintiles of phosphorus intake and 1 found no significant difference: HR: 0.86 (95% CI: 0.75, 0.98); HR: 0.83 (95% CI: 0.68, 1.02); and HR: 0.75 (95% CI: 0.45, 1.27), respectively. CONCLUSIONS We found no consistent association between total dietary phosphorus intake and BP in adults in the published literature nor any randomized trials designed to examine this association. This trial was registered at www.crd.york.ac.uk/prospero/ as CRD42017062489.
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Affiliation(s)
- Scott T McClure
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
| | - Casey M Rebholz
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
| | - Sibyl Medabalimi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
| | - Emily A Hu
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
| | - Zhe Xu
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
| | - Elizabeth Selvin
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
- Division of General Internal Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Lawrence J Appel
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
- Division of General Internal Medicine, Johns Hopkins School of Medicine, Baltimore, MD
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Li XC, Zheng X, Chen X, Zhao C, Zhu D, Zhang J, Zhuo JL. Genetic and genomic evidence for an important role of the Na +/H + exchanger 3 in blood pressure regulation and angiotensin II-induced hypertension. Physiol Genomics 2019; 51:97-108. [PMID: 30849009 PMCID: PMC6485378 DOI: 10.1152/physiolgenomics.00122.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The sodium (Na+)/hydrogen (H+) exchanger 3 (NHE3) and sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) are two of the most important Na+ transporters in the proximal tubules of the kidney. On the apical membrane side, NHE3 primarily mediates the entry of Na+ into and the exit of H+ from the proximal tubules, directly and indirectly being responsible for reabsorbing ~50% of filtered Na+ in the proximal tubules of the kidney. On the basolateral membrane side, Na+/K+-ATPase serves as a powerful engine driving Na+ out of, while pumping K+ into the proximal tubules against their concentration gradients. While the roles of NHE3 and Na+/K+-ATPase in proximal tubular Na+ transport under in vitro conditions are well recognized, their respective contributions to the basal blood pressure regulation and angiotensin II (ANG II)-induced hypertension remain poorly understood. Recently, we have been fortunate to be able to use genetically modified mouse models with global, kidney- or proximal tubule-specific deletion of NHE3 to directly determine the cause and effect relationship between NHE3, basal blood pressure homeostasis, and ANG II-induced hypertension at the whole body, kidney and/or proximal tubule levels. The purpose of this article is to review the genetic and genomic evidence for an important role of NHE3 with a focus in the regulation of basal blood pressure and ANG II-induced hypertension, as we learned from studies using global, kidney- or proximal tubule-specific NHE3 knockout mice. We hypothesize that NHE3 in the proximal tubules is necessary for maintaining basal blood pressure homeostasis and the development of ANG II-induced hypertension.
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Affiliation(s)
- Xiao C Li
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology; Division of Nephrology, Internal Medicine; Cardiovascular and Renal Research Center; The University of Mississippi Medical Center , Jackson, Mississippi
| | - Xiaowen Zheng
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology; Division of Nephrology, Internal Medicine; Cardiovascular and Renal Research Center; The University of Mississippi Medical Center , Jackson, Mississippi
| | - Xu Chen
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology; Division of Nephrology, Internal Medicine; Cardiovascular and Renal Research Center; The University of Mississippi Medical Center , Jackson, Mississippi
| | - Chunling Zhao
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology; Division of Nephrology, Internal Medicine; Cardiovascular and Renal Research Center; The University of Mississippi Medical Center , Jackson, Mississippi
| | - Dongmin Zhu
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology; Division of Nephrology, Internal Medicine; Cardiovascular and Renal Research Center; The University of Mississippi Medical Center , Jackson, Mississippi
| | - Jianfeng Zhang
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology; Division of Nephrology, Internal Medicine; Cardiovascular and Renal Research Center; The University of Mississippi Medical Center , Jackson, Mississippi
| | - Jia L Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology; Division of Nephrology, Internal Medicine; Cardiovascular and Renal Research Center; The University of Mississippi Medical Center , Jackson, Mississippi
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Bjornstad P, Singh SK, Snell-Bergeon JK, Lovshin JA, Lytvyn Y, Lovblom LE, Rewers MJ, Boulet G, Lai V, Tse J, Cham L, Orszag A, Weisman A, Keenan HA, Brent MH, Paul N, Bril V, Perkins BA, Cherney DZ. The relationships between markers of tubular injury and intrarenal haemodynamic function in adults with and without type 1 diabetes: Results from the Canadian Study of Longevity in Type 1 Diabetes. Diabetes Obes Metab 2019; 21:575-583. [PMID: 30311395 PMCID: PMC6368468 DOI: 10.1111/dom.13556] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/28/2018] [Accepted: 10/08/2018] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Our aim was to define the relationships between plasma biomarkers of kidney injury and intrarenal haemodynamic function (glomerular filtration rate [GFR], effective renal plasma flow [ERPF], renal vascular resistance [RVR]) in adults with type 1 diabetes (T1D). METHODS The study sample comprised patients with longstanding T1D (duration ≥50 years), among whom 44 were diabetic kidney disease (DKD) resistors (eGFR >60 mL/min/1.73 m2 and <30 mg/d urine albumin excretion) and 22 had DKD, in addition to 73 control participants. GFRINULIN and ERPFPAH were measured, RVR was calculated, and afferent (RA )/efferent (RE ) areteriolar resistances were derived from Gomez equations. Plasma neutrophil gelatinase-associated lipocalin (NGAL), β2 microglobulin (B2M), osteopontin (OPN) and uromodulin (UMOD) were measured using immunoassay kits from Meso Scale Discovery. RESULTS Plasma NGAL, B2M and OPN were higher and UMOD was lower in DKD patients vs DKD resistors and non-diabetic controls. In participants with T1D, plasma NGAL inversely correlated with GFR (r = -0.33; P = 0.006) and ERPF (r = -0.34; P = 0.006), and correlated positively with RA (r = 0.26; P = 0.03) and RVR (r = 0.31; P = 0.01). In participants without T1D, NGAL and B2M inversely correlated with GFR (NGAL r = -0.18; P = 0.13 and B2M r = -0.49; P < 0.0001) and with ERPF (NGAL r = -0.19; P = 0.1 and B2M r = -0.42; P = 0.0003), and correlated positively with RA (NGAL r = 0.19; P = 0.10 and B2M r = 0.3; P = 0.01) and with RVR (NGAL r = 0.20; P = 0.09 and B2M r = 0.34; P = 0.003). Differences were significant after adjusting for age, sex, HbA1c, SBP and LDL. There were statistical interactions between T1D status, B2M and intrarenal haemodynamic function (P < 0.05). CONCLUSIONS Elevated NGAL relates to intrarenal haemodynamic dysfunction in T1D, whereas elevated NGAL and B2M relate to intrarenal haemodynamic dysfunction in adults without T1D. These data may define a diabetes-specific interplay between tubular injury and intrarenal haemodynamic dysfunction.
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Affiliation(s)
- Petter Bjornstad
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
- Research Division, Barbara Davis Center for Diabetes. Aurora, Colorado, USA
| | - Sunita K. Singh
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | | | - Julie A. Lovshin
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | - Yuliya Lytvyn
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | - Leif E. Lovblom
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital. Toronto, Ontario, Canada
| | - Marian J. Rewers
- Research Division, Barbara Davis Center for Diabetes. Aurora, Colorado, USA
| | - Genevieve Boulet
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital. Toronto, Ontario, Canada
| | - Vesta Lai
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | - Josephine Tse
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | - Leslie Cham
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | - Andrej Orszag
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital. Toronto, Ontario, Canada
| | - Alanna Weisman
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital. Toronto, Ontario, Canada
| | - Hillary A. Keenan
- Research Division, Joslin Diabetes Center. Boston, Massachusetts, USA
| | - Michael H. Brent
- Department of Ophthalmology and Vision Sciences, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | - Narinder Paul
- Joint Department of Medical Imaging, Division of Cardiothoracic Radiology, University Health Network. Toronto, Ontario, Canada
| | - Vera Bril
- The Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Krembil Neuroscience Centre, Division of Neurology, Department of Medicine, University Health Network, University of Toronto. Toronto, Ontario, Canada
| | - Bruce A. Perkins
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital. Toronto, Ontario, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
| | - David Z.I. Cherney
- Division of Nephrology, Department of Medicine, University of Toronto. Toronto, Ontario, Canada
- Department of Physiology, University of Toronto
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[Which biological parameters for volemic status estimation?]. Nephrol Ther 2018; 14 Suppl 1:S83-S88. [PMID: 29606267 DOI: 10.1016/j.nephro.2018.02.012] [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] [Received: 01/24/2018] [Accepted: 02/01/2018] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Estimation of volemic status can be useful in the diagnosis of some hydro-electrolytic disorders such as hyponatremia and dyskalemia. As a matter of fact, clinical examination and classical biological parameters are not discriminant enough. The aim of this study was to determine the biological parameters that are better correlated to volemic status. METHOD Volemic status was established using extracellular fluid volume, measured by apparent distribution of inuline, in non-edematous patients and without cardiac or hepatic insufficiency. Patients were split in three groups according to their extracellular fluid volume: hypovolemic, normovolemic, and hypervolemic. Clinical and biological parameters were compared between the three groups and were correlated to extracellular fluid volume. RESULTS Data of 91 explorations were collected. There were no difference between groups regarding clinical parameters, plasma proteins, and urinary sodium excretion. Parameters better correlated to extracellular fluid volume were fasting calcium/creatinine ratio (r=0.51; P<0.0001), fasting urinary pH (r=0.43; P<0.0001), and plasma uric acid (r=-0.39; P=0.002). CONCLUSION In addition to uric acid, already proposed as a biological marker to estimate volemic status, fasting calciuria and fasting urinary pH could also be useful.
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The Na/K-ATPase Signaling: From Specific Ligands to General Reactive Oxygen Species. Int J Mol Sci 2018; 19:ijms19092600. [PMID: 30200500 PMCID: PMC6163532 DOI: 10.3390/ijms19092600] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/10/2018] [Accepted: 08/28/2018] [Indexed: 12/16/2022] Open
Abstract
The signaling function of the Na/K-ATPase has been established for 20 years and is widely accepted in the field, with many excellent reports and reviews not cited here. Even though there is debate about the underlying mechanism, the signaling function is unquestioned. This short review looks back at the evolution of Na/K-ATPase signaling, from stimulation by cardiotonic steroids (also known as digitalis-like substances) as specific ligands to stimulation by reactive oxygen species (ROS) in general. The interplay of cardiotonic steroids and ROS in Na/K-ATPase signaling forms a positive-feedback oxidant amplification loop that has been implicated in some pathophysiological conditions.
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Taub M. Gene Level Regulation of Na,K-ATPase in the Renal Proximal Tubule Is Controlled by Two Independent but Interacting Regulatory Mechanisms Involving Salt Inducible Kinase 1 and CREB-Regulated Transcriptional Coactivators. Int J Mol Sci 2018; 19:E2086. [PMID: 30021947 PMCID: PMC6073390 DOI: 10.3390/ijms19072086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 12/26/2022] Open
Abstract
For many years, studies concerning the regulation of Na,K-ATPase were restricted to acute regulatory mechanisms, which affected the phosphorylation of Na,K-ATPase, and thus its retention on the plasma membrane. However, in recent years, this focus has changed. Na,K-ATPase has been established as a signal transducer, which becomes part of a signaling complex as a consequence of ouabain binding. Na,K-ATPase within this signaling complex is localized in caveolae, where Na,K-ATPase has also been observed to regulate Inositol 1,4,5-Trisphosphate Receptor (IP3R)-mediated calcium release. This latter association has been implicated as playing a role in signaling by G Protein Coupled Receptors (GPCRs). Here, the consequences of signaling by renal effectors that act via such GPCRs are reviewed, including their regulatory effects on Na,K-ATPase gene expression in the renal proximal tubule (RPT). Two major types of gene regulation entail signaling by Salt Inducible Kinase 1 (SIK1). On one hand, SIK1 acts so as to block signaling via cAMP Response Element (CRE) Binding Protein (CREB) Regulated Transcriptional Coactivators (CRTCs) and on the other hand, SIK1 acts so as to stimulate signaling via the Myocyte Enhancer Factor 2 (MEF2)/nuclear factor of activated T cell (NFAT) regulated genes. Ultimate consequences of these pathways include regulatory effects which alter the rate of transcription of the Na,K-ATPase β1 subunit gene atp1b1 by CREB, as well as by MEF2/NFAT.
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Affiliation(s)
- Mary Taub
- Biochemistry Dept., Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main Street, Suite 4902, Buffalo, NY 14203, USA.
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Gao Y, Stuart D, Takahishi T, Kohan DE. Nephron-Specific Disruption of Nitric Oxide Synthase 3 Causes Hypertension and Impaired Salt Excretion. J Am Heart Assoc 2018; 7:JAHA.118.009236. [PMID: 29997131 PMCID: PMC6064857 DOI: 10.1161/jaha.118.009236] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND In vitro studies suggest that nephron nitric oxide synthase 3 (NOS3) modulates tubule Na+ transport. METHODS AND RESULTS To assess nephron NOS3 relevance in vivo, knockout (KO) mice with doxycycline-inducible nephron-wide deletion of NOS3 were generated. During 1 week of salt loading, KO mice, as compared with controls, had higher arterial pressure and Na+ retention, a tendency towards reduced plasma renin concentration, and unchanged glomerular filtration rate. Chronic high salt-treated KO mice had modestly decreased total NCC and total SPAK/OSR1 versus controls, however percent phosphorylation of NCC (at T53) and of SPAK/OSR1 was increased. In contrast, total and phosphorylated NKCC2 (at T96/101) were suppressed by 50% each in KO versus control mice after chronic salt intake. In response to an acute salt load, KO mice had delayed urinary Na+ excretion versus controls; this delay was completely abolished by furosemide, partially reduced by hydrochlorothiazide, but not affected by amiloride. After 4 hours of an acute salt load, phosphorylated and total NCC were elevated in KO versus control mice. Acute salt loading did not alter total NKCC2 or SPAK/OSR1 in KO versus control mice but increased the percent phosphorylation of NKCC2 (at T96/101 and S126) and SPAK/OSR1 in KO versus control mice. CONCLUSIONS These findings indicate that nephron NOS3 is involved in blood pressure regulation and urinary Na+ excretion during high salt intake. Nephron NOS3 appears to regulate NKCC2 and NCC primarily during acute salt loading. These effects of NOS3 may involve SPAK/OSR1 as well as other pathways.
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Affiliation(s)
- Yang Gao
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, UT
| | - Deborah Stuart
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, UT
| | | | - Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, UT
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Blood pressure regulation by the angiotensin type 1 receptor in the proximal tubule. Curr Opin Nephrol Hypertens 2018; 27:1-7. [PMID: 29045337 DOI: 10.1097/mnh.0000000000000373] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE OF REVIEW The renin-angiotensin system (RAS) plays a critical role in the pathogenesis of hypertension. Homeostatic actions of the RAS, such as increasing blood pressure (BP) and vasoconstriction, are mediated via type 1 (AT1) receptors for angiotensin II. All components of the RAS are present in the renal proximal tubule, which reabsorbs the bulk of the glomerular filtrate, making this segment of the nephron a location of great interest for solute handling under RAS influence. This review highlights recent studies that illustrate the key role of renal proximal tubule AT1 receptors in BP regulation. RECENT FINDINGS A variety of investigative approaches have demonstrated that angiotensin II signaling via AT1a receptors, specifically in the renal proximal tubule, is a major regulator of BP and sodium homeostasis. Reduction of proximal tubule AT1a receptors led to lower BPs, whereas overexpression generally caused increased BPs. SUMMARY AT1a receptors in the proximal tubule are critical to the regulation of BP by the kidney and the RAS. The pattern of BP modulation is associated with alterations in sodium transporters. As a key site for sodium homeostasis, the renal proximal tubule could hence be a potential target in the treatment of hypertension.
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Packer M. Role of the sodium-hydrogen exchanger in mediating the renal effects of drugs commonly used in the treatment of type 2 diabetes. Diabetes Obes Metab 2018; 20:800-811. [PMID: 29227582 DOI: 10.1111/dom.13191] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/07/2017] [Accepted: 12/07/2017] [Indexed: 01/19/2023]
Abstract
Diabetes is characterized by increased activity of the sodium-hydrogen exchanger (NHE) in the glomerulus and renal tubules, which contributes importantly to the development of nephropathy. Despite the established role played by the exchanger in experimental studies, it has not been specifically targeted by those seeking to develop novel pharmacological treatments for diabetes. This review demonstrates that many existing drugs that are commonly prescribed to patients with diabetes act on the NHE1 and NHE3 isoforms in the kidney. This action may explain their effects on sodium excretion, albuminuria and the progressive decline of glomerular function in clinical trials; these responses cannot be readily explained by the influence of these drugs on blood glucose. Agents that may affect the kidney in diabetes by virtue of an action on NHE include: (1) insulin and insulin sensitizers; (2) incretin-based agents; (3) sodium-glucose cotransporter 2 inhibitors; (4) antagonists of the renin-angiotensin system (angiotensin converting-enzyme inhibitors, angiotensin receptor blockers and angiotensin receptor neprilysin inhibitors); and (5) inhibitors of aldosterone action and cholesterol synthesis (spironolactone, amiloride and statins). The renal effects of each of these drug classes in patients with type 2 diabetes may be related to a single shared biological mechanism.
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Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas
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Pandey V, Garcia V, Gilani A, Mishra P, Zhang FF, Paudyal MP, Falck JR, Nasjletti A, Wang WH, Schwartzman ML. The Blood Pressure-Lowering Effect of 20-HETE Blockade in Cyp4a14(-/-) Mice Is Associated with Natriuresis. J Pharmacol Exp Ther 2017; 363:412-418. [PMID: 28912346 PMCID: PMC5698946 DOI: 10.1124/jpet.117.243618] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/13/2017] [Indexed: 01/22/2023] Open
Abstract
20-Hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE) has been linked to pro-hypertensive and anti-hypertensive actions through its ability to promote vasoconstriction and inhibit Na transport in the ascending limb of the loop of Henle, respectively. In this study, we assessed the effects of 20-HETE blockade on blood pressure, renal hemodynamics, and urinary sodium excretion in Cyp4a14(-/-) male mice, which display androgen-driven 20-HETE-dependent hypertension. Administration of 2,5,8,11,14,17-hexaoxanonadecan-19-yl 20-hydroxyicosa-6(Z),15(Z)-dienoate (20-SOLA), a water-soluble 20-HETE antagonist, in the drinking water normalized the blood pressure of male Cyp4a14(-/-) hypertensive mice (±124 vs. ±153 mmHg) while having no effect on age-matched normotensive wild-type (WT) male mice. Hypertension in Cyp4a14(-/-) male mice was accompanied by decreased renal perfusion and reduced glomerular filtration rates, which were corrected by treatment with 20-SOLA. Interestingly, Cyp4a14(-/-) male mice treated with 20-SOLA displayed increased urinary sodium excretion that was paralleled by the reduction of blood pressure suggestive of an antinatriuretic activity of endogenous 20-HETE in the hypertensive mice. This interpretation is in line with the observation that the natriuretic response to acute isotonic saline loading in hypertensive Cyp4a14(-/-) male mice was significantly impaired relative to that in WT mice; this impairment was corrected by 20-SOLA treatment. Hence, endogenous 20-HETE appears to promote sodium conservation in hypertensive Cyp4a14(-/-) male mice, presumably, as a result of associated changes in renal hemodynamics and/or direct stimulatory action on tubular sodium reabsorption.
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Affiliation(s)
- Varunkumar Pandey
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Victor Garcia
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Ankit Gilani
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Priyanka Mishra
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Frank Fan Zhang
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Mahesh P Paudyal
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - John R Falck
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Alberto Nasjletti
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
| | - Michal Laniado Schwartzman
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, New York (V.P., V.G., A.G., P.M., F.F.Z., A.N., W.-H.W., M.L.S.); and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas (M.P.P., J.R.F.)
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Li XC, Zhuo JL. Recent Updates on the Proximal Tubule Renin-Angiotensin System in Angiotensin II-Dependent Hypertension. Curr Hypertens Rep 2017; 18:63. [PMID: 27372447 DOI: 10.1007/s11906-016-0668-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
It is well recognized that the renin-angiotensin system (RAS) exists not only as circulating, paracrine (cell to cell), but also intracrine (intracellular) system. In the kidney, however, it is difficult to dissect the respective contributions of circulating RAS versus intrarenal RAS to the physiological regulation of proximal tubular Na(+) reabsorption and hypertension. Here, we review recent studies to provide an update in this research field with a focus on the proximal tubular RAS in angiotensin II (ANG II)-induced hypertension. Careful analysis of available evidence supports the hypothesis that both local synthesis or formation and AT1 (AT1a) receptor- and/or megalin-mediated uptake of angiotensinogen (AGT), ANG I and ANG II contribute to high levels of ANG II in the proximal tubules of the kidney. Under physiological conditions, nearly all major components of the RAS including AGT, prorenin, renin, ANG I, and ANG II would be filtered by the glomerulus and taken up by the proximal tubules. In ANG II-dependent hypertension, the expression of AGT, prorenin, and (pro)renin receptors, and angiotensin-converting enzyme (ACE) is upregulated rather than downregulated in the kidney. Furthermore, hypertension damages the glomerular filtration barrier, which augments the filtration of circulating AGT, prorenin, renin, ANG I, and ANG II and their uptake in the proximal tubules. Together, increased local ANG II formation and augmented uptake of circulating ANG II in the proximal tubules, via activation of AT1 (AT1a) receptors and Na(+)/H(+) exchanger 3, may provide a powerful feedforward mechanism for promoting Na(+) retention and the development of ANG II-induced hypertension.
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Affiliation(s)
- Xiao C Li
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, 2500 North State Street, Jackson, MS, 39216-4505, USA
| | - Jia L Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, 2500 North State Street, Jackson, MS, 39216-4505, USA.
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Israr-Qadir M, Jamil-Rana S, Nur O, Willander M. Zinc Oxide-Based Self-Powered Potentiometric Chemical Sensors for Biomolecules and Metal Ions. SENSORS (BASEL, SWITZERLAND) 2017; 17:E1645. [PMID: 28753916 PMCID: PMC5539625 DOI: 10.3390/s17071645] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 12/16/2022]
Abstract
Advances in the miniaturization and portability of the chemical sensing devices have always been hindered by the external power supply problem, which has focused new interest in the fabrication of self-powered sensing devices for disease diagnosis and the monitoring of analytes. This review describes the fabrication of ZnO nanomaterial-based sensors synthesized on different conducting substrates for extracellular detection, and the use of a sharp borosilicate glass capillary (diameter, d = 700 nm) to grow ZnO nanostructures for intracellular detection purposes in individual human and frog cells. The electrocatalytic activity and fast electron transfer properties of the ZnO materials provide the necessary energy to operate as well as a quick sensing device output response, where the role of the nanomorphology utilized for the fabrication of the sensor is crucial for the production of the operational energy. Simplicity, design, cost, sensitivity, selectivity and a quick and stable response are the most important features of a reliable sensor for routine applications. The review details the extra- and intra-cellular applications of the biosensors for the detection and monitoring of different metallic ions present in biological matrices, along with the biomolecules glucose and cholesterol.
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Affiliation(s)
- Muhammad Israr-Qadir
- Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden.
- Department of Materials Engineering, School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad 44000, Pakistan.
| | - Sadaf Jamil-Rana
- Department of Physics, Government College Women University, Sialkot 51310, Pakistan.
| | - Omer Nur
- Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden.
| | - Magnus Willander
- Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden.
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Takahashi-Iwanaga H, Kimura S, Konno K, Watanabe M, Iwanaga T. Intrarenal signaling mediated by CCK plays a role in salt intake-induced natriuresis. Am J Physiol Renal Physiol 2017; 313:F20-F29. [DOI: 10.1152/ajprenal.00539.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 11/22/2022] Open
Abstract
The natriuretic hormone CCK exhibits its gene transcripts in total kidney extracts. To test the possibility of CCK acting as an intrarenal mediator of sodium excretion, we examined mouse kidneys by 1) an in situ hybridization technique for CCK mRNA in animals fed a normal- or a high-sodium diet; 2) immuno-electron microscopy for the CCK peptide, 3) an in situ hybridization method and immunohistochemistry for the CCK-specific receptor CCKAR; 4) confocal image analysis of receptor-mediated Ca2+ responses in isolated renal tubules; and 5) metabolic cage experiments for the measurement of urinary sodium excretion in high-salt-fed mice either treated or untreated with the CCKAR antagonist lorglumide. Results showed the CCK gene to be expressed intensely in the inner medulla and moderately in the inner stripe of the outer medulla, with the expression in the latter being enhanced by high sodium intake. Immunoreactivity for the CCK peptide was localized to the rough endoplasmic reticulum of the medullary interstitial cells in corresponding renal regions, confirming it to be a secretory protein. Gene transcripts, protein products, and the functional activity for CCKAR were consistently localized to the late proximal tubule segments (S2 and S3) in the medullary rays, and the outer stripe of the outer medulla. Lorglumide significantly diminished natriuretic responses of mice to a dietary sodium load without altering the glomerular filtration rate. These findings suggest that the medullary interstitial cells respond to body fluid expansion by CCK release for feedback regulation of the late proximal tubular reabsorption.
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Affiliation(s)
| | - Shunsuke Kimura
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kohtarou Konno
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshihiko Iwanaga
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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Hallow KM, Gebremichael Y. A quantitative systems physiology model of renal function and blood pressure regulation: Model description. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2017; 6:383-392. [PMID: 28548387 PMCID: PMC5488122 DOI: 10.1002/psp4.12178] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/05/2017] [Accepted: 01/23/2017] [Indexed: 01/13/2023]
Abstract
Renal function plays a central role in cardiovascular, kidney, and multiple other diseases, and many existing and novel therapies act through renal mechanisms. Even with decades of accumulated knowledge of renal physiology, pathophysiology, and pharmacology, the dynamics of renal function remain difficult to understand and predict, often resulting in unexpected or counterintuitive therapy responses. Quantitative systems pharmacology modeling of renal function integrates this accumulated knowledge into a quantitative framework, allowing evaluation of competing hypotheses, identification of knowledge gaps, and generation of new experimentally testable hypotheses. Here we present a model of renal physiology and control mechanisms involved in maintaining sodium and water homeostasis. This model represents the core renal physiological processes involved in many research questions in drug development. The model runs in R and the code is made available. In a companion article, we present a case study using the model to explore mechanisms and pharmacology of salt‐sensitive hypertension.
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Affiliation(s)
- K M Hallow
- University of Georgia, Athens, Georgia, USA
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46
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Elemental composition of dietary supplements most consumed in Belo Horizonte, Brazil, analysed by k 0-INAA. J Radioanal Nucl Chem 2017. [DOI: 10.1007/s10967-017-5222-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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47
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Tu W, Eckert GJ, Decker BS, Howard Pratt J. Varying Influences of Aldosterone on the Plasma Potassium Concentration in Blacks and Whites. Am J Hypertens 2017; 30:490-494. [PMID: 28338830 DOI: 10.1093/ajh/hpx006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Aldosterone acts to restrain the extracellular potassium (K+) concentration. Blacks have on average lower plasma aldosterone concentrations (PACs) than Whites. Whether this ethnic difference is associated with similar changes in the concentration of K+ is unclear. METHODS Subjects were Blacks and Whites from an observational study of blood pressure regulation. PAC was known to be significantly lower in Blacks than Whites. We sought to test the hypothesis that the concentration of K+ remains constant despite variability in PAC. Initial enrollment took place in childhood in 1986. Some of the original enrollees were studied again in adulthood: 160 healthy Blacks and 271 healthy Whites (ages 5 to 39 years; all were studied as children and as adults). RESULTS Plasma renin activity [a biomarker of angiotensin II and, more proximally, extracellular fluid volume (ECFV)] and PAC were lower in Blacks (P < 0.0354 and P < 0.001, respectively, for all ages). At the same time no ethnic difference in levels of K+ was observed regardless of age. Plasma K+ concentration and PAC associated differently based on ethnicity: PAC increased in Blacks by 1.5-2.0 and in Whites by 2.3-3.0 ng/dl per mmol/l increase in K+ (P < 0.001). CONCLUSIONS Lower aldosterone levels in Blacks did not translate into higher K+ concentrations. We speculate that reaching the right concentration of K+ was an endpoint of aldosterone production in the presence of varying levels of ECFV and angiotensin II.
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Affiliation(s)
- Wanzhu Tu
- Department of Biostatistics, Indiana University Center for Aging Research, Regenstrief Institute, Indianapolis, Indiana, USA
- Indiana University Center for Aging Research, Regenstrief Institute, Indianapolis, Indiana, USA
| | - George J. Eckert
- Department of Biostatistics, Indiana University Center for Aging Research, Regenstrief Institute, Indianapolis, Indiana, USA
| | - Brian S. Decker
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - John Howard Pratt
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Roudebush V.A. Medical Center, Indianapolis, Indiana, USA
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Fenton RA, Poulsen SB, de la Mora Chavez S, Soleimani M, Dominguez Rieg JA, Rieg T. Renal tubular NHE3 is required in the maintenance of water and sodium chloride homeostasis. Kidney Int 2017; 92:397-414. [PMID: 28385297 DOI: 10.1016/j.kint.2017.02.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 01/25/2017] [Accepted: 02/02/2017] [Indexed: 11/30/2022]
Abstract
The sodium/proton exchanger isoform 3 (NHE3) is expressed in the intestine and the kidney, where it facilitates sodium (re)absorption and proton secretion. The importance of NHE3 in the kidney for sodium chloride homeostasis, relative to the intestine, is unknown. Constitutive tubule-specific NHE3 knockout mice (NHE3loxloxCre) did not show significant differences compared to control mice in body weight, blood pH or bicarbonate and plasma sodium, potassium, or aldosterone levels. Fluid intake, urinary flow rate, urinary sodium/creatinine, and pH were significantly elevated in NHE3loxloxCre mice, while urine osmolality and GFR were significantly lower. Water deprivation revealed a small urinary concentrating defect in NHE3loxloxCre mice on a control diet, exaggerated on low sodium chloride. Ten days of low or high sodium chloride diet did not affect plasma sodium in control mice; however, NHE3loxloxCre mice were susceptible to low sodium chloride (about -4 mM) or high sodium chloride intake (about +2 mM) versus baseline, effects without differences in plasma aldosterone between groups. Blood pressure was significantly lower in NHE3loxloxCre mice and was sodium chloride sensitive. In control mice, the expression of the sodium/phosphate co-transporter Npt2c was sodium chloride sensitive. However, lack of tubular NHE3 blunted Npt2c expression. Alterations in the abundances of sodium/chloride cotransporter and its phosphorylation at threonine 58 as well as the abundances of the α-subunit of the epithelial sodium channel, and its cleaved form, were also apparent in NHE3loxloxCre mice. Thus, renal NHE3 is required to maintain blood pressure and steady-state plasma sodium levels when dietary sodium chloride intake is modified.
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Affiliation(s)
- Robert A Fenton
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Søren B Poulsen
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark; VA San Diego Healthcare System, San Diego, California, USA
| | | | - Manoocher Soleimani
- Department of Medicine, University of Cincinnati, Cincinnati, Ohio, USA; Research Services, Veterans Affairs Medical Center, Cincinnati, Ohio, USA
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA.
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Lewis JM, Fontrier TH, Coley JL. Respiratory alkalosis may impair the production of vitamin D and lead to significant morbidity, including the fibromyalgia syndrome. Med Hypotheses 2017; 102:99-101. [PMID: 28478843 DOI: 10.1016/j.mehy.2017.03.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 03/07/2017] [Indexed: 01/27/2023]
Abstract
Hyperventilation caused by physical and/or psychological stress may lead to significant respiratory alkalosis and an elevated systemic pH. The alkalotic pH may in turn suppress the normal renal release of phosphate into the urine, thereby interrupting the endogenous production of 1,25-dihydroxyvitamin D (calcitriol). This could cause a shortfall in its normal production, leading to a variety of adverse consequences. It might partially explain the pathogenesis of acute mountain sickness, a treatable disease characterized by severe hyperventilation secondary to the hypoxia of high altitude exposure. Milder degrees of hyperventilation due to different forms of stress may produce other conditions which share characteristics with acute mountain sickness. One of these may be the fibromyalgia syndrome, a chronic painful disorder for which no satisfactory treatment exists. Should fibromyalgia and acute mountain sickness have a common etiology, may they also share a common form of treatment? Evidence is presented to support this hypothesis.
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Affiliation(s)
- John M Lewis
- Department of Clinical Nutrition, Wake Forest Baptist Medical Center, Winston-Salem, NC 27157, USA.
| | - Toinette H Fontrier
- Department of Clinical Nutrition, Wake Forest Baptist Medical Center, Winston-Salem, NC 27157, USA
| | - J Lynn Coley
- Department of Clinical Nutrition, Wake Forest Baptist Medical Center, Winston-Salem, NC 27157, USA
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50
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Liu J, Yan Y, Nie Y, Shapiro JI. Na/K-ATPase Signaling and Salt Sensitivity: The Role of Oxidative Stress. Antioxidants (Basel) 2017; 6:E18. [PMID: 28257114 PMCID: PMC5384181 DOI: 10.3390/antiox6010018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/10/2017] [Accepted: 02/22/2017] [Indexed: 02/07/2023] Open
Abstract
Other than genetic regulation of salt sensitivity of blood pressure, many factors have been shown to regulate renal sodium handling which contributes to long-term blood pressure regulation and have been extensively reviewed. Here we present our progress on the Na/K-ATPase signaling mediated sodium reabsorption in renal proximal tubules, from cardiotonic steroids-mediated to reactive oxygen species (ROS)-mediated Na/K-ATPase signaling that contributes to experimental salt sensitivity.
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Affiliation(s)
- Jiang Liu
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA.
| | - Yanling Yan
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA.
| | - Ying Nie
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA.
| | - Joseph I Shapiro
- Department of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA
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