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Johnston JG, Wingo CS. Potassium Homeostasis and WNK Kinases in the Regulation of the Sodium-Chloride Cotransporter: Hyperaldosteronism and Its Metabolic Consequences. KIDNEY360 2022; 3:1823-1828. [PMID: 36514400 PMCID: PMC9717643 DOI: 10.34067/kid.0005752022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 10/12/2022] [Indexed: 12/05/2022]
Affiliation(s)
- Jermaine G. Johnston
- Department of Medicine, University of Florida, Gainesville, Florida,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida,Veterans Administration Medical Center, North Florida/South Georgia Veterans Health Administration, Gainesville, Florida
| | - Charles S. Wingo
- Department of Medicine, University of Florida, Gainesville, Florida,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida,Veterans Administration Medical Center, North Florida/South Georgia Veterans Health Administration, Gainesville, Florida
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2
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Chang HC, Cheng HM, Chen CH, Wang TD, Soenarta AA, Turana Y, Teo BW, Tay JC, Tsoi K, Wang JG, Kario K. Dietary intervention for the management of hypertension in Asia. J Clin Hypertens (Greenwich) 2020; 23:538-544. [PMID: 33274585 PMCID: PMC8029518 DOI: 10.1111/jch.14116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/09/2020] [Accepted: 11/18/2020] [Indexed: 11/28/2022]
Abstract
Hypertension is among the leading global risks for premature death. As the risks substantially increase along with the elevated blood pressure, a small reduction of blood pressure could have prevented numerous cardiovascular events in general population. Evidence has shown that dietary intervention is a cost-effective strategy that has been broadly advocated in the published guidelines. However, the implementation could be limited by different food cultures. This review details the mechanisms of each dietary intervention approach, evidence, and the implications in Asian populations, and the perspective of future research.
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Affiliation(s)
- Hao-Chih Chang
- Department of Medicine, Taipei Veterans General Hospital Su-Ao and Yuan-Shan Branch, Yilan, Taiwan
| | - Hao-Min Cheng
- Department of Medicine, Taipei Veterans General Hospital Su-Ao and Yuan-Shan Branch, Yilan, Taiwan.,Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Department of Medical Education, Center for Evidence-based Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Public Health and Community Medicine Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Chen-Huan Chen
- Department of Medicine, Taipei Veterans General Hospital Su-Ao and Yuan-Shan Branch, Yilan, Taiwan.,Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Department of Medical Education, Center for Evidence-based Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Public Health and Community Medicine Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Tzung-Dau Wang
- Division of Cardiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Arieska Ann Soenarta
- Department of Cardiology and Vascular Medicine, Faculty of Medicine, University of Indonesia-National Cardiovascular Center, Harapan Kita, Jakarta, Indonesia
| | - Yuda Turana
- School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Jakarta, Indonesia
| | - Boon Wee Teo
- Division of Nephrology Department of Medicine, Yong Loo Lin School of Medicine, Singapore, Singapore
| | - Jam Chin Tay
- Department of General Medicine, Tan Tock Seng Hospital, Singapore, Singapore
| | - Kelvin Tsoi
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Ji-Guang Wang
- Department of Hypertension, Centre for Epidemiological Studies and Clinical Trials, the Shanghai Institute of Hypertension, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Kazuomi Kario
- Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, Tochigi, Japan
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Abstract
Eating more potassium may reduce blood pressure and the occurrence of other cardiovascular diseases by actions on various systems, including the vasculature, the sympathetic nervous system, systemic metabolism, and body fluid volume. Among these, the kidney plays a major role in the potassium-rich diet-mediated blood pressure reduction. PURPOSE OF REVIEW: To provide an overview of recent discoveries about the mechanisms by which a potassium-rich diet leads to natriuresis. RECENT FINDINGS: Although the distal convoluted tubule (DCT) is a short part of the nephron that reabsorbs salt, via the sodium-chloride cotransporter (NCC), it is highly sensitive to changes in plasma potassium concentration. Activation or inhibition of NCC raises or lowers blood pressure. Recent work suggests that extracellular potassium concentration is sensed by the DCT via intracellular chloride concentration which regulates WNK kinases in the DCT. High-potassium diet targets NCC in the DCT, resulting in natriuresis and fluid volume reduction, which are protective from hypertension and other cardiovascular problems.
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Affiliation(s)
- Xiao-Tong Su
- School of Medicine, Oregon Health and Science University, Portland, OR USA
| | - Chao-Ling Yang
- School of Medicine, Oregon Health and Science University, Portland, OR USA
| | - David H. Ellison
- School of Medicine, Oregon Health and Science University, Portland, OR USA ,Oregon Clinical & Translational Research Institute, SN4N, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 USA ,Veterans Administration Portland Health Care System, Portland, OR USA
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4
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Li J, Xu S, Yang L, Yang J, Wang CJ, Weinstein AM, Palmer LG, Wang T. Sex difference in kidney electrolyte transport II: impact of K + intake on thiazide-sensitive cation excretion in male and female mice. Am J Physiol Renal Physiol 2019; 317:F967-F977. [PMID: 31390232 PMCID: PMC6843050 DOI: 10.1152/ajprenal.00125.2019] [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] [Received: 03/12/2019] [Revised: 07/15/2019] [Accepted: 07/22/2019] [Indexed: 11/22/2022] Open
Abstract
We studied sex differences in response to high K+ (HK) intake on thiazide-sensitive cation (Na+ and K+) excretion in wild-type (WT) and ANG II receptor subtype 1a (AT1aR) knockout (KO) mice. Renal clearance experiments were performed to examine Na+-Cl- cotransporter (NCC) activity on mice fed with control and HK (5% KCl, 7 days) diets. Hydrochlorothiazide (HCTZ)-induced changes in urine volume, glomerular filtration rate, absolute Na+ and K+ excretion, and fractional excretion were compared. HK-induced changes in NCC, Na+/H+ exchanger isoform 3 (NHE3), and ENaC expression were examined by Western blot analysis. In WT animals under the control diet, HCTZ-induced cation excretion was greater in female animals, reflecting larger increases in Na+ excretion, since there was little sex difference in HCTZ-induced K+ excretion. Under the HK diet, the sex difference in HCTZ-induced cation excretion was reduced because of larger increments in K+ excretion in male animals. The fraction of K+ excretion was 57 ± 5% in male WT animals and 36 ± 4% in female WT animals (P < 0.05), but this difference was absent in AT1aR KO mice. NCC abundance was higher in female animals than in male animals but decreased by similar fractions on HK diet. NHE3 abundance decreased, whereas cleaved forms of γ-ENaC increased, with HK in all groups; these changes were similar in male and female animals and were not significantly affected by AT1aR ablation. These results indicate that, with the HK diet, male animals display greater distal Na+ delivery and greater activation of K+ secretion mechanisms, all suggesting a more powerful male adaptation to HK intake.
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Affiliation(s)
- Jing Li
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Shuhua Xu
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Lei Yang
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York
| | - Janey Yang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Claire J Wang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York
| | - Lawrence G Palmer
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York
| | - Tong Wang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
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5
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O'Donnell M, Mente A, Rangarajan S, McQueen MJ, O'Leary N, Yin L, Liu X, Swaminathan S, Khatib R, Rosengren A, Ferguson J, Smyth A, Lopez-Jaramillo P, Diaz R, Avezum A, Lanas F, Ismail N, Yusoff K, Dans A, Iqbal R, Szuba A, Mohammadifard N, Oguz A, Yusufali AH, Alhabib KF, Kruger IM, Yusuf R, Chifamba J, Yeates K, Dagenais G, Wielgosz A, Lear SA, Teo K, Yusuf S. Joint association of urinary sodium and potassium excretion with cardiovascular events and mortality: prospective cohort study. BMJ 2019; 364:l772. [PMID: 30867146 PMCID: PMC6415648 DOI: 10.1136/bmj.l772] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To evaluate the joint association of sodium and potassium urinary excretion (as surrogate measures of intake) with cardiovascular events and mortality, in the context of current World Health Organization recommendations for daily intake (<2.0 g sodium, >3.5 g potassium) in adults. DESIGN International prospective cohort study. SETTING 18 high, middle, and low income countries, sampled from urban and rural communities. PARTICIPANTS 103 570 people who provided morning fasting urine samples. MAIN OUTCOME MEASURES Association of estimated 24 hour urinary sodium and potassium excretion (surrogates for intake) with all cause mortality and major cardiovascular events, using multivariable Cox regression. A six category variable for joint sodium and potassium was generated: sodium excretion (low (<3 g/day), moderate (3-5 g/day), and high (>5 g/day) sodium intakes) by potassium excretion (greater/equal or less than median 2.1 g/day). RESULTS Mean estimated sodium and potassium urinary excretion were 4.93 g/day and 2.12 g/day, respectively. After a median follow-up of 8.2 years, 7884 (6.1%) participants had died or experienced a major cardiovascular event. Increasing urinary sodium excretion was positively associated with increasing potassium excretion (unadjusted r=0.34), and only 0.002% had a concomitant urinary excretion of <2.0 g/day of sodium and >3.5 g/day of potassium. A J-shaped association was observed of sodium excretion and inverse association of potassium excretion with death and cardiovascular events. For joint sodium and potassium excretion categories, the lowest risk of death and cardiovascular events occurred in the group with moderate sodium excretion (3-5 g/day) and higher potassium excretion (21.9% of cohort). Compared with this reference group, the combinations of low potassium with low sodium excretion (hazard ratio 1.23, 1.11 to 1.37; 7.4% of cohort) and low potassium with high sodium excretion (1.21, 1.11 to 1.32; 13.8% of cohort) were associated with the highest risk, followed by low sodium excretion (1.19, 1.02 to 1.38; 3.3% of cohort) and high sodium excretion (1.10, 1.02 to 1.18; 29.6% of cohort) among those with potassium excretion greater than the median. Higher potassium excretion attenuated the increased cardiovascular risk associated with high sodium excretion (P for interaction=0.007). CONCLUSIONS These findings suggest that the simultaneous target of low sodium intake (<2 g/day) with high potassium intake (>3.5 g/day) is extremely uncommon. Combined moderate sodium intake (3-5 g/day) with high potassium intake is associated with the lowest risk of mortality and cardiovascular events.
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Affiliation(s)
- Martin O'Donnell
- Population Health Research Institute, DBCVS Research Institute, McMaster University, 237 Barton St East, Hamilton, ON L8L 2X2, Canada
- HRB-Clinical Research Facility, Galway University Hospital, NUI Galway, Galway, Ireland
| | - Andrew Mente
- Population Health Research Institute, DBCVS Research Institute, McMaster University, 237 Barton St East, Hamilton, ON L8L 2X2, Canada
| | - Sumathy Rangarajan
- Population Health Research Institute, DBCVS Research Institute, McMaster University, 237 Barton St East, Hamilton, ON L8L 2X2, Canada
| | - Matthew J McQueen
- Population Health Research Institute, DBCVS Research Institute, McMaster University, 237 Barton St East, Hamilton, ON L8L 2X2, Canada
| | - Neil O'Leary
- HRB-Clinical Research Facility, Galway University Hospital, NUI Galway, Galway, Ireland
| | - Lu Yin
- Medical Research & Biometrics Centre, National Centre for Cardiovascular Diseases Cardiovascular, Fengcunxili, Mentougou District, Beijing, China
| | - Xiaoyun Liu
- Medical Research & Biometrics Centre, National Centre for Cardiovascular Diseases Cardiovascular, Fengcunxili, Mentougou District, Beijing, China
| | - Sumathi Swaminathan
- Division of Nutrition, St John's Research Institute, Bangalore, Karnataka, India
| | - Rasha Khatib
- Departments of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Annika Rosengren
- Sahlgrenska Academy, University of Gothenburg, and Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - John Ferguson
- HRB-Clinical Research Facility, Galway University Hospital, NUI Galway, Galway, Ireland
| | - Andrew Smyth
- HRB-Clinical Research Facility, Galway University Hospital, NUI Galway, Galway, Ireland
| | - Patricio Lopez-Jaramillo
- Fundacion Oftalmologica de Santander (FOSCAL), Medical School, Universidad de Santander, Floridablanca-Santander, Colombia
| | - Rafael Diaz
- Estudios Clinicos Latinoamerica ECLA, Instituto Cardiovascular de Rosario, Rosario, Santa Fe, Argentina
| | - Alvaro Avezum
- Dante Pazzanese Institute of Cardiology, Sao Paulo, Brazil
| | | | - Noorhassim Ismail
- Department of Community Health. University Kebangsaan Malaysia Medical Centre, Malaysia
| | - Khalid Yusoff
- Faculty of Medicine and Health Sciences, UCSI University, Kuala Lumpur, Malaysia
| | - Antonio Dans
- University of the Philippines-Manila, Ermita, Manila, Philippines
| | - Romaina Iqbal
- Departments of Community Health Sciences and Medicine, Aga Khan University, Karachi, Pakistan
| | - Andrzej Szuba
- Division of Angiology, Wroclaw Medical University, Wroclaw, Poland
| | - Noushin Mohammadifard
- Isfahan Cardiovascular Research Centre, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Atyekin Oguz
- Istanbul Medeniyet University, Faculty of Medicine, Department of Internal Medicine, Istanbul, Turkey
| | - Afzal Hussein Yusufali
- Hatta Hospital, Dubai Medical University, Dubai Health Authority. Dubai, United Arab Emirates
| | - Khalid F Alhabib
- Department of Cardiac Sciences, King Fahad Cardiac Centre, College of Medicine, King Saud University. Riyadh, Saudi Arabia
| | - Iolanthe M Kruger
- Faculty of Health Science, North-West University, Potchefstroom campus, Potchefstroom, South Africa
| | - Rita Yusuf
- School of Life Sciences and The Centre for Health, Population and Development. Independent University, Bangladesh, Dhaka, Bangladesh
| | - Jephat Chifamba
- University of Zimbabwe, College of Health Sciences, Physiology Department, Harare, Zimbabwe
| | - Karen Yeates
- Department of Medicine, Division of Nephrology, Queen's University, Kingston, Canada
| | - Gilles Dagenais
- Laval University Heart and Lungs Institute, Quebec City, QC, Canada
| | | | - Scott A Lear
- Faculty of Health Sciences, Simon Fraser University, and Division of Cardiology, Providence Health Care, BC, Canada
| | - Koon Teo
- Population Health Research Institute, DBCVS Research Institute, McMaster University, 237 Barton St East, Hamilton, ON L8L 2X2, Canada
| | - Salim Yusuf
- Population Health Research Institute, DBCVS Research Institute, McMaster University, 237 Barton St East, Hamilton, ON L8L 2X2, Canada
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Molecular mechanisms for the regulation of blood pressure by potassium. CURRENT TOPICS IN MEMBRANES 2019; 83:285-313. [PMID: 31196607 DOI: 10.1016/bs.ctm.2019.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has been well documented that the amount of potassium in the diet is associated with blood pressure levels in the population: the higher the potassium consumption, the lower the blood pressure and the cardiovascular mortality. In the last few years certain mechanisms for potassium regulation of salt reabsorption in the kidney have been elucidated at the molecular level. In this work we discuss the evidence demonstrating the relationship between potassium intake and blood pressure levels in human populations and in animal models, as well as the experimental data that reveal the effects of potassium on transepithelial Na+ reabsorption in different nephron segments. We also discuss the physiological relevance of K+-induced natriuresis, and finally, we focus on the molecular mechanisms by which extracellular potassium modulates the activity of the renal NaCl cotransporter, which is the mechanism that has been best dissected so far.
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7
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Weinstein AM. A mathematical model of the rat kidney: K +-induced natriuresis. Am J Physiol Renal Physiol 2017; 312:F925-F950. [PMID: 28179254 PMCID: PMC6148314 DOI: 10.1152/ajprenal.00536.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 01/27/2023] Open
Abstract
A model of the rat nephron (Weinstein. Am J Physiol Renal Physiol 308: F1098-F1118, 2015) has been extended with addition of medullary vasculature. Blood vessels contain solutes from the nephron model, plus additional species from the model of Atherton et al. (Am J Physiol Renal Fluid Electrolyte Physiol 247: F61-F72, 1984), representing hemoglobin buffering. In contrast to prior models of the urine-concentrating mechanism, reflection coefficients for DVR are near zero. Model unknowns are initial proximal tubule pressures and flows, connecting tubule pressure, and medullary interstitial pressures and concentrations. The model predicts outer medullary (OM) interstitial gradients for Na+, K+, CO2, and [Formula: see text], such that at OM-IM junction, the respective concentrations relative to plasma are 1.2, 3.0, 2.7, and 8.0; within IM, there is high urea and low [Formula: see text], with concentration ratios of 11 and 0.5 near the papillary tip. Quantitative similarities are noted between K+ and urea handling (medullary delivery and permeabilities). The model K+ gradient is physiologic, and the urea gradient is steeper due to restriction of urea permeability to distal collecting duct. Nevertheless, the predicted urea gradient is less than expected, suggesting reconsideration of proposals of an unrecognized reabsorptive urea flux. When plasma K+ is increased from 5.0 to 5.5 mM, Na+ and K+ excretion increase 2.3- and 1.3-fold, respectively. The natriuresis derives from a 3.3% decrease in proximal Na+ reabsorption and occurs despite delivery-driven increases in Na+ reabsorption in distal segments; kaliuresis derives from a 30% increase in connecting tubule Na+ delivery. Thus this model favors the importance of proximal over distal events in K+-induced diuresis.
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Affiliation(s)
- Alan M Weinstein
- Departments of Physiology and Biophysics and of Medicine, Weill Medical College of Cornell University, New York, New York
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8
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Ellison DH, Terker AS, Gamba G. Potassium and Its Discontents: New Insight, New Treatments. J Am Soc Nephrol 2015; 27:981-9. [PMID: 26510885 DOI: 10.1681/asn.2015070751] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Hyperkalemia is common in patients with impaired kidney function or who take drugs that inhibit the renin-angiotensin-aldosterone axis. During the past decade, substantial advances in understanding how the body controls potassium excretion have been made, which may lead to improved standard of care for these patients. Renal potassium disposition is primarily handled by a short segment of the nephron, comprising part of the distal convoluted tubule and the connecting tubule, and regulation results from the interplay between aldosterone and plasma potassium. When dietary potassium intake and plasma potassium are low, the electroneutral sodium chloride cotransporter is activated, leading to salt retention. This effect limits sodium delivery to potassium secretory segments, limiting potassium losses. In contrast, when dietary potassium intake is high, aldosterone is stimulated. Simultaneously, potassium inhibits the sodium chloride cotransporter. Because more sodium is then delivered to potassium secretory segments, primed by aldosterone, kaliuresis results. When these processes are disrupted, hyperkalemia results. Recently, new agents capable of removing potassium from the body and treating hyperkalemia have been tested in clinical trials. This development suggests that more effective and safer approaches to the prevention and treatment of hyperkalemia may be on the horizon.
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Affiliation(s)
- David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon; Renal Section, Veterans Affairs Portland Health Care System, Portland, Oregon; and
| | - Andrew S Terker
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
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9
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Yee J. Hypertension in CKD: Sodium still at the nexus. Adv Chronic Kidney Dis 2015; 22:173-6. [PMID: 25908464 DOI: 10.1053/j.ackd.2015.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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McCarty MF. Rationale for a novel nutraceutical complex 'K-water': potassium taurine bicarbonate (PTB). Med Hypotheses 2006; 67:65-70. [PMID: 16516402 DOI: 10.1016/j.mehy.2005.09.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 09/05/2005] [Indexed: 11/24/2022]
Abstract
Potassium taurine bicarbonate (PTB), an equimolar blend of potassium bicarbonate and taurine, provides a convenient and feasible means of delivering physiologically significant doses of potassium, taurine, and organic base when dissolved in water ("K-water"). This brief essay reviews the versatile and complementary health benefits that likely would accrue in individuals making regular use of K-water; in particular, an adequate intake of PTB could be expected to aid blood pressure control, lessen risk for atherosclerosis and its thromboembolic complications (particularly stroke), promote maintenance of bone density, help to prevent calcium renal stones, and possibly reduce risk for weight gain and diabetes.
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Affiliation(s)
- Mark F McCarty
- Natural Alternatives International, 1185 Linda Vista Dr., San Marcos, CA 92078, United States.
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11
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McCarty MF. Marinobufagenin may mediate the impact of salty diets on left ventricular hypertrophy by disrupting the protective function of coronary microvascular endothelium. Med Hypotheses 2005; 64:854-63. [PMID: 15694707 DOI: 10.1016/j.mehy.2003.11.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2003] [Accepted: 11/21/2003] [Indexed: 01/19/2023]
Abstract
Individuals who eat salty diets and who are "salt-sensitive" tend to have increased left ventricular mass, independent of blood pressure; this phenomenon awaits an explanation. It is clear that local up-regulation of angiotensin II (AngII) production and activity play a key role in the induction of left ventricular hypertrophy (LVH). Recent evidence suggests that a healthy coronary microvascular endothelium opposes this effect by serving as a paracrine source of nitric oxide (NO), a natural antagonist of AngII activity, and that up-regulation of this mechanism can account for the protective role of bradykinin with respect to LVH. The coronary microvasculature also possesses NAD(P)H oxidase activity that can generate superoxide, inimical to the bioactivity of endothelial NO. There is now good reason to believe that the triterpenoid marinobufagenin (MBG), a selective inhibitor of the alpha-1 isoform of the sodium pump, mediates the impact of salty diets on blood pressure; production of MBG by the adrenal cortex is boosted when salt-sensitive animals are fed salty diets. It is hypothesized that coronary microvascular endothelium expresses the alpha-1 isoform of the sodium pump, and that MBG thus can target this endothelium. If that is the case, MBG would be expected to decrease membrane potential in these cells; as a consequence, superoxide production would be up-regulated, NO synthase activity would be down-regulated, and myocardial NO bioactivity would thus be suppressed. This would offer a satisfying explanation for the impact of salt and salt-sensitivity on risk for LVH. If expression of the alpha-1 isoform of the sodium pump is a more general property of vascular endothelium, MBG may suppress NO bioactivity in other regions of the vascular tree, thereby contributing to other adverse effects elicited by salty diets: reduced arterial compliance, medial hypertrophy, impaired endothelium-dependent vasodilation, hypertensive/diabetic glomerulopathy, increased risk for stroke, and hypertension.
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Affiliation(s)
- Mark F McCarty
- Pantox Laboratories, 4622 Santa Fe Street, San Diego, CA 92109, USA.
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12
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McCarty MF. Marinobufagenin may mediate the impact of salty diets on left ventricular hypertrophy by disrupting the protective function of coronary microvascular endothelium. Med Hypotheses 2004; 62:993-1002. [PMID: 15142663 DOI: 10.1016/j.mehy.2003.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2003] [Accepted: 11/11/2003] [Indexed: 01/06/2023]
Abstract
Individuals who eat salty diets and who are "salt-sensitive" tend to have increased left ventricular mass, independent of blood pressure; this phenomenon awaits an explanation. It is clear that local up-regulation of angiotensin II (AngII) production and activity play a key role in the induction of left ventricular hypertrophy (LVH). Recent evidence suggests that a healthy coronary microvascular endothelium opposes this effect by serving as a paracrine source of nitric oxide (NO), a natural antagonist of AngII activity, and that up-regulation of this mechanism can account for the protective role of bradykinin with respect to LVH. The coronary microvasculature also possesses NAD(P)H oxidase activity that can generate superoxide, inimical to the bioactivity of endothelial NO. There is now good reason to believe that the triterpenoid marinobufagenin (MBG), a selective inhibitor of the alpha-1 isoform of the sodium pump, mediates the impact of salty diets on blood pressure;production of MBG by the adrenal cortex is boosted when salt-sensitive animals are fed salty diets. It is hypothesized that coronary microvascular endothelium expresses the alpha-1 isoform of the sodium pump, and that MBG thus can target this endothelium. If that is the case, MBG would be expected to decrease membrane potential in these cells;as a consequence, superoxide production would be up-regulated, NO synthase activity would be down-regulated, and myocardial NO bioactivity would thus be suppressed. This would offer a satisfying explanation for the impact of salt and salt-sensitivity on risk for LVH. If expression of the alpha-1 isoform of the sodium pump is a more general property of vascular endothelium, MBG may suppress NO bioactivity in other regions of the vascular tree, thereby contributing to other adverse effects elicited by salty diets: reduced arterial compliance, medial hypertrophy, impaired endothelium-dependent vasodilation, hypertensive/diabetic glomerulopathy, increased risk for stroke, and hypertension.
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Affiliation(s)
- Mark F McCarty
- Pantox Laboratories, 4622 Santa Fe Street, San Diego, CA 92109, USA.
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13
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Coruzzi P, Gualerzi M, Parati G, Brambilla L, Brambilla V, Di Rienzo M, Novarini A. Potassium supplementation improves the natriuretic response to central volume expansion in primary aldosteronism. Metabolism 2003; 52:1597-600. [PMID: 14669162 DOI: 10.1016/j.metabol.2003.07.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Potassium depletion induced by dietary potassium restriction is known to cause sodium retention, while potassium supplementation is known to increase urinary sodium excretion. However, the ability of potassium deficiency to affect mineralocorticoid-induced sodium retention in aldosterone-producing adenoma (APA) subjects has not been extensively investigated, neither in baseline conditions nor when facilitating natriuresis through a physiological manoeuver such as central blood volume expansion. With the aim of testing the hypothesis that potassium supplementation would attenuate the mineralocorticoid-induced sodium retention, in 7 APA patients elevation of serum potassium was obtained by infusion of isosmotic potassium chloride (KCl) at a constant rate of 36 mmol/h for a 2-hour period for 5 consecutive days. The same patients were also submitted to acute central volume expansion by head-out water immersion (WI) associated with either low or normal serum potassium levels. The assessment of natriuresis in baseline condition and during WI was also performed in 10 age-matched control subjects. Central hypervolemia by WI induced a significant natriuretic response in APA hypokalemic subjects; on the other hand, in the same APA subjects giving potassium supplementation, WI-induced urinary sodium excretion was significantly higher (P <.001) than that obtained during WI at normal potassium intake (hypokalemic condition). Blood pressure responses and hormonal profiles were almost superimposable during the 2 WI experiments performed at different serum potassium levels. By confirming that amelioration of hypokalemia attenuates mineralocorticoid-induced sodium retention, this study also suggests that potassium intake may represent an important determinant of mineralocorticoid escape.
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Affiliation(s)
- Paolo Coruzzi
- Dipartimento di Scienze Cliniche, Fondazione Don C. Gnocchi-ONLUS, University of Parma, Italy
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Silver RB, Soleimani M. H+-K+-ATPases: regulation and role in pathophysiological states. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:F799-811. [PMID: 10362769 DOI: 10.1152/ajprenal.1999.276.6.f799] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular cloning experiments have identified the existence of two H+-K+-ATPases (HKAs), colonic and gastric. Recent functional and molecular studies indicate the presence of both transporters in the kidney, which are presumed to mediate the exchange of intracellular H+ for extracellular K+. On the basis of these studies, a picture is evolving that indicates differential regulation of HKAs at the molecular level in acid-base and electrolyte disorders. Of the two transporters, gastric HKA is expressed constitutively along the length of the collecting duct and is responsible for H+ secretion and K+ reabsorption under normal conditions and may be stimulated with acid-base perturbations and/or K+ depletion. This regulation may be species specific. To date there are no data to indicate that the colonic HKA (HKAc) plays a role in H+ secretion or K+ reabsorption under normal conditions. However, HKAc shows adaptive regulation in pathophysiological conditions such as K+ depletion, NaCl deficiency, and proximal renal tubular acidosis, suggesting an important role for this exchanger in potassium, HCO-3, and sodium (or chloride) reabsorption in disease states. The purpose of this review is to summarize recent functional and molecular studies on the regulation of HKAs in physiological and pathophysiological states. Possible signals responsible for regulation of HKAs in these conditions will be discussed. Furthermore, the role of these transporters in acid-base and electrolyte homeostasis will be evaluated in the context of genetically altered animals deficient in HKAc.
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Affiliation(s)
- R B Silver
- Department of Physiology and Biophysics, Cornell University Medical College, New York, New York 10021, USA
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Barri YM, Wingo CS. The effects of potassium depletion and supplementation on blood pressure: a clinical review. Am J Med Sci 1997; 314:37-40. [PMID: 9216439 DOI: 10.1097/00000441-199707000-00008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Nonpharmacologic treatment currently is recognized as an important part in the treatment of hypertension, and the role of dietary potassium intake in blood pressure (BP) control is becoming quite evident. Clinical studies have examined the mechanism by which hypokalemia can increase BP and the benefit of a large potassium intake on BP control. Epidemiologic data suggest that potassium intake and BP are correlated inversely. In normotensive subjects, those who are salt sensitive or who have a family history of hypertension appear to benefit most from the hypotensive effects of potassium supplementation. The greatest hypotensive effect of potassium supplementation occurs in patients with severe hypertension. This effect is pronounced with prolonged potassium supplementation. The antihypertensive effect of increased potassium intake appears to be mediated by several factors, which include enhancing natriuresis, modulating baroreflex sensitivity, direct vasodilation, or lowering cardiovascular reactivity to norepinephrine or angiotensin II. Potassium repletion in patients with diuretic-induced hypokalemia improves BP control. An increase in potassium intake should be included in the nonpharmacologic management of patients with uncomplicated hypertension.
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Affiliation(s)
- Y M Barri
- Division of Nephrology, University of Arkansas for Medical Sciences, Little Rock, USA
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Barri YM, Wingo CS. The Effects of Potassium Depletion and Supplementation on Blood Pressure: A Clinical Review. Am J Med Sci 1997. [DOI: 10.1016/s0002-9629(15)40154-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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