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Köchli S, Schutte AE, Botha-Le Roux S, Gafane-Matemane LF, Smith W, van Rooyen JM, Mokwatsi GG, Kruger R. Potassium excretion and blood pressure are associated with heart rate variability in healthy black adults: The African-PREDICT study. Nutr Metab Cardiovasc Dis 2021; 31:1071-1080. [PMID: 33549447 DOI: 10.1016/j.numecd.2020.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND AIMS Heart rate variability (HRV) is a main determinant of autonomic function and related to the development of hypertension and cardiovascular (CV) disease. Hypertension develops in black populations at an earlier age, which could be due to differences in the autonomic nervous system activity and sodium/potassium handling in black and white populations. We investigated whether HRV is associated with 24 h urinary sodium and potassium excretion and blood pressure (BP) in a young bi-ethnic cohort. METHODS AND RESULTS We examined 423 black and 483 white healthy adults (aged 24.5 ± 3.1 years) for 24 h HRV, including standard deviation of normal RR intervals (SDNN) reflecting autonomic variations over time, and root mean square of successive differences (RMSSD) reflecting parasympathetic activity. We measured 24 h urinary sodium and potassium concentration and BP. The black group had lower SDNN and potassium excretion as well as higher RMSSD, sodium and Na/k ratio compared to the white group (all p < 0.05). Only in black individuals, urinary potassium excretion was independently and negatively associated with SDNN (β[95% CI];-0.26[-0.50;-0.02]ms) and RMSSD (-0.14[-0.27;-0.01]ms, p < 0.05). One unit increase in sodium/potassium (Na/K) ratio was associated with higher SDNN (β[95% CI]; 3.04[0.89; 5.19]ms) and RMSSD (1.60[0.41; 2.78]ms) in the black cohort only (both p < 0.001). In both groups elevated 24 h diastolic BP was associated with lower RMSSD (p < 0.05). CONCLUSION Lower potassium excretion and higher Na/K ratio related independently to higher HRV in young and healthy black adults. A better ethnic-specific understanding of sodium and potassium handling is required as part of preventive cardiology, especially in black individuals. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03292094; URL: https://clinicaltrials.gov/ct2/show/NCT03292094.
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Affiliation(s)
- Sabrina Köchli
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa
| | - Aletta E Schutte
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Medical Research Council: Unit for Hypertension and Cardiovascular Disease, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa; School of Population Health, University of New South Wales, The George Institute for Global Health, Sydney, Australia
| | - Shani Botha-Le Roux
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Medical Research Council: Unit for Hypertension and Cardiovascular Disease, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Lebo F Gafane-Matemane
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Medical Research Council: Unit for Hypertension and Cardiovascular Disease, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Wayne Smith
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Medical Research Council: Unit for Hypertension and Cardiovascular Disease, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Johannes M van Rooyen
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Medical Research Council: Unit for Hypertension and Cardiovascular Disease, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Gontse G Mokwatsi
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Medical Research Council: Unit for Hypertension and Cardiovascular Disease, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Ruan Kruger
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Medical Research Council: Unit for Hypertension and Cardiovascular Disease, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa.
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Effects of High Salt-Low Potassium Diet on Blood Pressure and Vascular Reactivity in Male Sprague Dawley Rats. J Cardiovasc Pharmacol 2019; 71:340-346. [PMID: 29554004 DOI: 10.1097/fjc.0000000000000578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Sodium (Na) intake increases vascular reactivity. Whether low potassium (K) intake affects vascular reactivity-associated blood pressure (BP) changes is uncertain. This study aimed to determine whether Na-induced increases in BP and vascular reactivity are altered by low K intake. Male Sprague Dawley rats were assigned to 3 dietary groups for 6 weeks: a standard Na-K diet (control, n = 12), a high Na-normal K diet (HS-NormK, n = 12), and a high Na-low K diet (HS-LowK, n = 12). BP was measured at baseline and after the dietary intervention. Na and K excretions and vascular reactivity were measured after the dietary intervention. The Na/K ratio was significantly higher in the HS-LowK compared with the other groups. Systolic and diastolic BPs increased significantly in the HS-NormK and HS-LowK groups. In mesenteric arteries, the dose-response curves for phenylephrine-induced contractions shifted to the left and the EC50 (mean ± SD) was significantly lower in the HS-NormK (0.51 ± 0.17 μM, P = 0.003) and HS-LowK (0.69 ± 0.14 μM, P = 0.005) groups compared with the control (3.24 ± 0.79 μM). Systolic (r = -0.58 P = 0.002) and diastolic (r = -0.61 P = 0.001) BPs were associated with the EC50 of phenylephrine-induced contraction in mesenteric arteries. High Na intake induces increased alpha-1 receptor responsiveness in mesenteric arteries, which may be responsible for the increase in BP and is not affected by low dietary K intake.
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Choi CY, Park JS, Yoon KT, Gil HW, Lee EY, Hong SY. Intra-dialytic hypertension is associated with high mortality in hemodialysis patients. PLoS One 2017; 12:e0181060. [PMID: 28742805 PMCID: PMC5526505 DOI: 10.1371/journal.pone.0181060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 06/26/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Intra-dialytic hypertension (IDH) is emerging as an important issue in hemodialysis patients. Its risk factors and clinical outcomes are unclear. METHODS A total of 73 prevalent hemodialysis patients were enrolled. They included 14 (19.2%) patients with baseline IDH and 59 patients without IDH. Their clinical parameters, laboratory parameters, and mortality were investigated over 78 months. RESULTS The risks factor of IDH included low serum potassium levels, low ultrafiltration, and low arm muscle area. Lower median survival was evident in the IDH group compared to the non-IDH group, but was not significantly different. After adjusting for relevant confounders for age, the IDH group displayed 2.846 times higher mortality rate than the non-IDH Group (adjusted hazard ratio: 2.846; 95% confidence interval: 1.081-7.490; P = 0.034). CONCLUSION IDH is associated with high mortality in hemodialysis patients. Clinicians should be aware of the risk factors. Future research studies are needed to explore the mechanisms involved in the association between IDH and mortality.
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Affiliation(s)
- Chi-Young Choi
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, Korea
| | - Jae Seok Park
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, Korea
| | - Kyu Tae Yoon
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, Korea
| | - Hyo Wook Gil
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, Korea
| | - Eun Young Lee
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, Korea
- * E-mail:
| | - Sae Yong Hong
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, Korea
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Poorolajal J, Zeraati F, Soltanian AR, Sheikh V, Hooshmand E, Maleki A. Oral potassium supplementation for management of essential hypertension: A meta-analysis of randomized controlled trials. PLoS One 2017; 12:e0174967. [PMID: 28419159 PMCID: PMC5395164 DOI: 10.1371/journal.pone.0174967] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/17/2017] [Indexed: 12/21/2022] Open
Abstract
IMPORTANCE Increased dietary potassium intake is thought to be associated with low blood pressure (BP). Whether potassium supplementation may be used as an antihypertensive agent is a question that should be answered. OBJECTIVE To assess the effect of oral potassium supplementation on blood pressure in patients with primary hypertension. SEARCH METHODS We searched Medline, Web of Science, Scopus, Cochrane Central Register of Controlled Trials until October 2016. We also screened reference lists of articles and previous reviews. We applied no language restrictions. SELECTION CRITERIA We included randomized placebo-controlled clinical trials addressing the effect of potassium supplementation on primary hypertension for a minimum of 4 weeks. DATA COLLECTION AND ANALYSIS We extracted data on systolic and diastolic BP (SBP and DBP) at the final follow-up. We explored the heterogeneity across studies using Cochran's test and I2 statistic and assessed the probability of publication bias using Begg's and Egger's tests. We reported the mean difference (MD) of SBP and DBP in a random-effects model. RESULTS We found a total of 9059 articles and included 23 trials with 1213 participants. Compared to placebo, potassium supplementation resulted in modest but significant reductions in both SBP (MD -4.25 mmHg; 95% CI: -5.96 to -2.53; I2 = 41%) and DBP (MD -2.53 mmHg; 95% CI: -4.05 to -1.02; I2 = 65%). According to the change-score analysis, based on 8 out of 23 trials, compared to baseline, the mean changes in SBP (MD -8.89 mmHg; 95% CI: -13.67 to -4.11) and DBP (MD -6.42 mmHg; 95% CI: -10.99 to -1.84) was significantly higher in the intervention group than the control group. CONCLUSIONS Our findings indicated that potassium supplementation is a safe medication with no important adverse effects that has a modest but significant impact BP and may be recommended as an adjuvant antihypertensive agent for patients with essential hypertension.
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Affiliation(s)
- Jalal Poorolajal
- Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
- Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
- Noncommunicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Fatemeh Zeraati
- Medicinal Plants and Natural Products Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Ali Reza Soltanian
- Noncommunicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
- Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Vida Sheikh
- Department of Internal Medicine, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Elham Hooshmand
- Department of Public Health, Neyshabur University of Medical Sciences, Neyshabur, Iran
| | - Akram Maleki
- Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
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Penton D, Czogalla J, Loffing J. Dietary potassium and the renal control of salt balance and blood pressure. Pflugers Arch 2015; 467:513-30. [PMID: 25559844 DOI: 10.1007/s00424-014-1673-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 01/09/2023]
Abstract
Dietary potassium (K(+)) intake has antihypertensive effects, prevents strokes, and improves cardiovascular outcomes. The underlying mechanism for these beneficial effects of high K(+) diets may include vasodilation, enhanced urine flow, reduced renal renin release, and negative sodium (Na(+)) balance. Indeed, several studies demonstrate that dietary K(+) intake induces renal Na(+) loss despite elevated plasma aldosterone. This review briefly highlights the epidemiological and experimental evidences for the effects of dietary K(+) on arterial blood pressure. It discusses the pivotal role of the renal distal tubule for the regulation of urinary K(+) and Na(+) excretion and blood pressure and highlights that it depends on the coordinated interaction of different nephron portions, epithelial cell types, and various ion channels, transporters, and ATPases. Moreover, we discuss the relevance of aldosterone and aldosterone-independent factors in mediating the effects of an altered K(+) intake on renal K(+) and Na(+) handling. Particular focus is given to findings suggesting that an aldosterone-independent downregulation of the thiazide-sensitive NaCl cotransporter significantly contributes to the natriuretic and antihypertensive effect of a K(+)-rich diet. Last but not least, we refer to the complex signaling pathways enabling the kidney to adapt its function to the homeostatic needs in response to an altered K(+) intake. Future work will have to further address the underlying cellular and molecular mechanism and to elucidate, among others, how an altered dietary K(+) intake is sensed and how this signal is transmitted to the different epithelial cells lining the distal tubule.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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Wang WH, Zhang C, Lin DH, Wang L, Graves JP, Zeldin DC, Capdevila JH. Cyp2c44 epoxygenase in the collecting duct is essential for the high K+ intake-induced antihypertensive effect. Am J Physiol Renal Physiol 2014; 307:F453-60. [PMID: 24966089 DOI: 10.1152/ajprenal.00123.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cytochrome P-450, family 2, subfamily c, polypeptide 44 (Cyp2c44) epoxygenase metabolizes arachidonic acid (AA) to epoxyeicosatrienoic acids (EETs) in kidney and vascular tissues. In the present study, we used real-time quantitative PCR techniques to examine the effect of high salt or high K(+) (HK) intake on the expression of Cyp2c44, a major Cyp2c epoxygenase in the mouse kidney. We detected Cyp2c44 in the proximal convoluted tubule, thick ascending limb, distal convoluted tubule (DCT)/connecting tubule (CNT), and collecting duct (CD). A high-salt diet increased the expression of Cyp2c44 in the thick ascending limb and DCT/CNT but not in the proximal convoluted tubule and CD. In contrast, an increase in dietary K(+) intake augmented Cyp2c44 expression only in the DCT/CNT and CD. Neither high salt nor HK intake had a significant effect on the blood pressure (BP) of wild-type mice. However, HK but not high salt intake increased BP in CD-specific, Cyp2c44 conditional knockout (KO) mice. Amiloride, an epithelial Na(+) channel (ENaC) inhibitor, normalized the BP of KO mice fed HK diets, suggesting that lack of Cyp2c44 in the CD enhances ENaC activity and increases Na(+) absorption in KO mice fed HK diets. This notion was supported by metabolic cage experiments demonstrating that renal Na(+) excretion was compromised in KO mice fed HK diets. Also, patch-clamp experiments demonstrated that 11,12-EET, a major Cyp2c44 product, but not AA inhibited ENaC activity in the cortical CD of KO mice. We conclude that Cyp2c44 in the CD is required for preventing the excessive Na(+) absorption induced by HK intake by inhibition of ENaC and facilitating renal Na(+) excretion.
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Affiliation(s)
- Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York;
| | - Chengbiao Zhang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Lijun Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Joan P Graves
- Division of Intramural Research, National Institute of Environmental Health Science, Research Triangle Park, North Carolina; and
| | - Darryl C Zeldin
- Division of Intramural Research, National Institute of Environmental Health Science, Research Triangle Park, North Carolina; and
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Rosa RM, De Jesus E, Sperling K, Suh A, Gmurczyk A, Myrie KA, Rosner K, Lerma E, Yu W, Breuer R, Young JB. Gastrointestinal and renal excretion of potassium in African-Americans and White Americans. J Hypertens 2013; 30:2373-7. [PMID: 23111624 DOI: 10.1097/hjh.0b013e32835a27b3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Several studies have confirmed the remarkable observation that cumulative urinary potassium (K(+)) excretion is less in African-Americans than White Americans even when identical amounts of potassium are provided in the diet. This study was designed to examine whether this decrease in urinary potassium could be compensatory to an increase in gastrointestinal excretion of potassium in African-Americans. METHODS Twenty-three young, healthy, normotensive participants of both sexes and races were placed on a fixed diet of 100 mEq per day of K(+) and 180 mEq per day of sodium (Na(+)) for 9 days. All urine and stool were collected daily and analyzed for electrolytes. Blood was obtained for determination of electrolytes, blood urea nitrogen (BUN), creatinine, glucose, insulin, renin, and aldosterone at the beginning and at the end of the study period. RESULTS Cumulative urinary excretion of K(+) was significantly less in African-Americans (609 ± 31 mEq) compared with White Americans (713 ± 22 mEq, P = 0.015). There was no significant racial difference, however, in the cumulative gastrointestinal excretion of K (105 ± 11 versus 95 ± 9 mEq, P = 0.28) in African-Americans versus White Americans, respectively. CONCLUSION The racial difference in urinary K(+) handling manifested by decreased excretion of K(+) in African-Americans cannot be attributed to an increase in net gastrointestinal excretion of this cation.
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Affiliation(s)
- Robert M Rosa
- Division of Nephrology/Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611-3008, USA.
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Marketou ME, Zacharis EA, Parthenakis F, Kochiadakis GE, Maragkoudakis S, Chlouverakis G, Vardas PE. Association of sodium and potassium intake with ventricular arrhythmic burden in patients with essential hypertension. ACTA ACUST UNITED AC 2013; 7:276-82. [PMID: 23659779 DOI: 10.1016/j.jash.2013.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 04/03/2013] [Accepted: 04/03/2013] [Indexed: 01/11/2023]
Abstract
BACKGROUND Hypertensive populations suffer from an increased susceptibility to ventricular arrhythmias and sudden cardiac death. A high-salt diet appears to be a major factor involved in cardiovascular complications in hypertension. We examined the relationship between dietary salt and potassium, as indicated by urinary sodium (UNa), urinary potassium (UK), and urinary sodium/potassium ratio (UNa/K), and the arrhythmic burden in patients with essential hypertension. METHODS We included 255 consecutive adult patients with well-controlled hypertension who were being followed in the hypertension outpatient clinic of a university tertiary hospital and complained of episodes of atypical chest pain and/or palpitations. All underwent 24-hour ambulatory electrocardiograph monitoring and their UNa, UK, and UNa/K ratio from 24-hour urinary excretion specimens were evaluated. RESULTS No significant correlation was found between premature supraventricular contractions and the parameters that were examined. However, the percentage of premature ventricular contractions (PVC%) showed a weak positive association with UNa (r = 0.2; P = .001) and a moderate negative association with UK (r = -0.396; P < .001). The partial correlation coefficient of PVC% with the UNa/UK ratio remained significant even after controlling for left ventricular mass index (r = 0.437; P < .001). CONCLUSIONS A higher UNa/UK excretion ratio is significantly associated with PVCs, indicating an increased susceptibility to ventricular arrhythmias even among hypertensives with well-controlled blood pressure. Our findings reinforce recommendations for dietary interventions in those populations.
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Affiliation(s)
- Maria E Marketou
- Department of Cardiology, University Hospital of Heraklion, Crete, Greece.
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Bhalla M, Aziz H, Richard E, Lipkowitz MS, Bhatnagar V. Serum potassium predicts time to blood pressure response among African Americans with hypertensive nephrosclerosis. J Hum Hypertens 2012; 27:393-6. [PMID: 23151750 PMCID: PMC4537064 DOI: 10.1038/jhh.2012.47] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
It is not known whether serum potassium levels affect blood pressure response to anti-hypertensive medication. The African American trial of Kidney disease and Hypertension (AASK) Genomics Study (N=828) is a subset of the AASK trial that randomized 1,094 African American men and women with hypertensive nephrosclerosis to ramipril, amlodipine or metoprolol. Participants were also randomized to a usual (102–107 mmHg) or low (≤92 mmHg) mean arterial pressure (MAP) treatment goal. Time-to-event analyses were used to determine the relationship between serum potassium prior to randomization and time (days) to reach an MAP of 107 mmHg. Mean baseline serum potassium was 4.22 (standard deviation +/− 0.56 and range 2.8–6.0) mmol/L and the median days to reach target MAP was 32 (interquartile range 8–95) days. The adjusted hazard ratio (HR) for each 1mmol/L increase in serum potassium was 1.31 (95%CI: 1.08–1.59) in the usual MAP group, and 1.21 (95%CI: 1.02–1.44) in the low MAP group. Secondary findings suggested that women in the usual MAP group on amlodipine were more likely to reach target MAP compared to women randomized to ramipril (HR: 2.05, 95%CI: 1.30–3.21). Older subjects in the low MAP group (≥55 years) were also more likely to reach target MAP on amlodipine compared to ramipril (HR: 1.57, 95%CI: 1.03–2.38). Serum potassium appears to be a significant predictor of time to blood pressure response, independent of drug class. Results also suggest a benefit of using amlodipine when more rapid blood pressure control is clinically indicated among women and more aggressively managed older subjects.
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Affiliation(s)
- M Bhalla
- Department of Veterans Affairs, Health Services Research and Development, San Diego, CA, USA
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Blood Pressure-Lowering Mechanisms of the DASH Dietary Pattern. J Nutr Metab 2012; 2012:472396. [PMID: 22496969 PMCID: PMC3306995 DOI: 10.1155/2012/472396] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 10/07/2011] [Indexed: 12/24/2022] Open
Abstract
Potential blood pressure- (BP-) lowering mechanisms of the DASH dietary pattern were measured in 20 unmedicated hypertensive adults in a controlled feeding study. At screening, participants averaged 44.3 ± 7.8 years, BMI 33.9 ± 6.6 Kg/m(2), and BP 144.2 ± 9.38/88.5 ± 6.03 mmHg. All consumed a control diet for one week, then were randomized to control or DASH for another two weeks (week one and two). With DASH, but not controls, SBP fell by 10.65 ± 12.89 (P = 0.023) and 9.60 ± 11.23 (P = 0.039) mmHg and DBP by 5.95 ± 8.01 (P = 0.069) and 8.60 ± 9.13 mmHg (P = 0.011) at the end of week one and two, respectively. Univariate regressions showed that changes in urinary sodium/potassium ratio (β = 1.99) and plasma renin activity (β = -15.78) and percent change in plasma nitrite after hyperemia were associated with SBP changes at week one (all P < 0.05). Plasma nitrite following hyperemia showed a treatment effect (P = 0.014) and increased at week two (P = 0.001). Pulse wave velocity decreased over time with DASH (trend P = 0.019), and reached significance at week two (P = 0.026). This response may be mediated by an improvement in upregulation of nitric oxide bioavailability. Early natriuresis and reductions in oxidative stress cannot be ruled out. Future studies are needed to verify these findings, assess the possibility of earlier effects, and examine other potential mediators.
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Sun P, Antoun J, Lin DH, Yue P, Gotlinger KH, Capdevila J, Wang WH. Cyp2c44 epoxygenase is essential for preventing the renal sodium absorption during increasing dietary potassium intake. Hypertension 2011; 59:339-47. [PMID: 22184322 DOI: 10.1161/hypertensionaha.111.178475] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The aim of this study is to test whether the Cyp2c44 epoxygenase-dependent metabolism of arachidonic acid prevents the hypertensive effect of a high K (HK) intake by inhibiting the epithelial sodium channel (ENaC) activity. A HK intake elevated Cyp2c44 mRNA expression and 11,12-epoxyeicosatrienoic acid levels in the cortical collecting duct in Cyp2c44(+/+) mice (wild-type [wt]). However, an HK intake failed to increase 11,12-epoxyeicosatrienoic acid formation in the cortical collecting ducts of Cyp2c44(-/-) mice. Moreover, increasing K intake enhanced arachidonic acid-induced inhibition of ENaC in the wt but not in Cyp2c44(-/-) mice. In contrast, 11,12-epoxyeicosatrienoic acid, a Cyp2c44 metabolite, inhibited ENaC in the wt and Cyp2c44(-/-) mice. The notion that Cyp2c44 is the epoxygenase responsible for mediating the inhibitory effects of arachidonic acid on ENaC is further suggested by the observation that inhibiting Cyp-epoxygenase increased the whole-cell Na currents in principal cells of wt but not in Cyp2c44(-/-) mice. Feeding mice with an HK diet raised the systemic blood pressures of Cyp2c44(-/-) mice but was without an effect on wt mice. Moreover, application of amiloride abolished the HK-induced hypertension in Cyp2c44(-/-) mice. The HK-induced hypertension of Cyp2c44(-/-) mice was accompanied by decreasing 24-hour urinary Na excretion and increasing the plasma Na concentration, and the effects were absent in wt mice. In contrast, disruption of the Cyp2c44 gene did not alter K excretion. We conclude that Cyp2c44 epoxygenase mediates the inhibitory effect of arachidonic acid on ENaC and that Cyp2c44 functions as an HK-inducible antihypertensive enzyme responsible for inhibiting ENaC activity and Na absorption in the aldosterone-sensitive distal nephron.
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Affiliation(s)
- Peng Sun
- Department of Pharmacology, New York Medical College, 15 Dana Rd, Valhalla, NY 10595, USA
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Sun P, Lin DH, Yue P, Jiang H, Gotlinger KH, Schwartzman ML, Falck JR, Goli M, Wang WH. High potassium intake enhances the inhibitory effect of 11,12-EET on ENaC. J Am Soc Nephrol 2010; 21:1667-77. [PMID: 20595684 DOI: 10.1681/asn.2009111110] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
High dietary potassium stimulates the renal expression of cytochrome P450 (CYP) epoxygenase 2C23, which metabolizes arachidonic acid (AA). Because the AA metabolite 11,12-epoxyeicosatrienoic acid (11,12-EET) can inhibit the epithelial sodium channel (ENaC) in the cortical collecting duct, we tested whether dietary potassium modulates ENaC function. High dietary potassium increased 11,12-EET in the isolated cortical collecting duct, an effect mimicked by inhibiting the angiotensin II type I receptor with valsartan. In patch-clamp experiments, a high potassium intake or treatment with valsartan enhanced AA-induced inhibition of ENaC, an effect mediated by a CYP-epoxygenase-dependent pathway. Moreover, high dietary potassium and valsartan each augmented the inhibitory effect of 11,12-EET on ENaC. Liquid chromatography/mass spectrometry showed that the rate of EET conversion to dihydroxyeicosatrienoic acids (DHET) was lower in renal tissue obtained from rats on a high-potassium diet than from those on a control diet, but this was not a result of altered expression of soluble epoxide hydrolase (sEH). Instead, suppression of sEH activity seemed to be responsible for the 11,12-EET-mediated enhanced inhibition of ENaC in animals on a high-potassium diet. Patch-clamp experiments demonstrated that 11,12-DHET was a weak inhibitor of ENaC compared with 11,12-EET, whereas 8,9- and 14,15-DHET were not. Furthermore, inhibition of sEH enhanced the 11,12-EET-induced inhibition of ENaC similar to high dietary potassium. In conclusion, high dietary potassium enhances the inhibitory effect of AA and 11,12-EET on ENaC by increasing CYP epoxygenase activity and decreasing sEH activity, respectively.
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Affiliation(s)
- Peng Sun
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA
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Houston MC, Harper KJ. Potassium, magnesium, and calcium: their role in both the cause and treatment of hypertension. J Clin Hypertens (Greenwich) 2008; 10:3-11. [PMID: 18607145 PMCID: PMC8109864 DOI: 10.1111/j.1751-7176.2008.08575.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Despite advances in the prevention and treatment of hypertension over the past decade, hypertension remains an important public health challenge. Recent efforts to reduce the prevalence of hypertension have focused on nonpharmacologic means, specifically diet. An increased intake of minerals such as potassium, magnesium, and calcium by dietary means has been shown in some but not all studies to reduce blood pressure in patients with hypertension. This review will discuss the roles of potassium, magnesium, and calcium in the prevention and treatment of essential hypertension with specific emphasis on clinical trial evidence, mechanism of action, and recommendations for dietary intake of these minerals. A high intake of these minerals through increased consumption of fruits and vegetables may improve blood pressure levels and reduce coronary heart disease and stroke.
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Affiliation(s)
- Mark C Houston
- Vanderbilt University School of Medicine, Nashville, TN 37205, USA.
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Jehle S, Zanetti A, Muser J, Hulter HN, Krapf R. Partial Neutralization of the Acidogenic Western Diet with Potassium Citrate Increases Bone Mass in Postmenopausal Women with Osteopenia. J Am Soc Nephrol 2006; 17:3213-22. [PMID: 17035614 DOI: 10.1681/asn.2006030233] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Chronic acid loads are an obligate consequence of the high animal/grain protein content of the Western diet. The effect of this diet-induced metabolic acidosis on bone mass is controversial. In a randomized, prospective, controlled, double-blind trial, 161 postmenopausal women (age 58.6 +/- 4.8 yr) with low bone mass (T score -1 to -4) were randomly assigned to 30 mEq of oral potassium (K) citrate (Kcitrate) or 30 mEq of K chloride (KCl) daily. The primary end point was the intergroup difference in mean percentage change in bone mineral density (BMD) at lumbar spine (L2 through L4) after 12 mo. Compared with the women who received KCl, women who received Kcitrate exhibited an intergroup increase in BMD (+/-SE) of 1.87 +/- 0.50% at L2 through L4 (P < 0.001), of 1.39 +/- 0.48% (P < 0.001) at femoral neck, and of 1.98 +/- 0.51% (P < 0.001) at total hip. Significant secondary end point intragroup changes also were found: Kcitrate increased L2 through L4 BMD significantly from baseline at months 3, 9, and 12 and reached a month 12 increase of 0.89 +/- 0.30% (P < 0.05), whereas the KCl arm showed a decreased L2 through L4 BMD by -0.98 +/- 0.38% (P < 0.05), significant only at month 12. Intergroup differences for distal radius and total body were NS. The Kcitrate-treated group demonstrated a sustained and significant reduction in urinary calcium excretion and a significant increase in urinary citrate excretion, with increased citrate excretion indicative of sustained systemic alkalization. Urinary bone resorption marker excretion rates were significantly reduced by Kcitrate, and for deoxypyridinoline, the intergroup difference was significant. Urinary net acid excretion correlated inversely and significantly with the change in BMD in a subset of patients. Large and significant reductions in BP were observed for both K supplements during the entire 12 mo. Bone mass can be increased significantly in postmenopausal women with osteopenia by increasing their daily alkali intake as citrate, and the effect is independent of reported skeletal effects of K.
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Affiliation(s)
- Sigrid Jehle
- Department of Medicine, University of Basel, Bruderholz/Basel, Switzerland
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16
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Abstract
BACKGROUND African Americans appear relatively potassium (K(+))-deficient compared with Caucasian Americans whether on unregulated diets or on diets controlled for K(+) content. METHODS To determine whether extrarenal K(+) disposal was affected by race, KCl (0.5 mEq/kg in 0.9% saline) was infused over 48 minutes to 12 African American and 12 Caucasian American normotensive, healthy subjects. Identical infusions were administered before and after 10 days of fixed electrolyte intake. In addition to serum K(+), glucose, insulin, renin, and aldosterone were measured in blood, and K(+) and sodium (Na(+)) in urine voided spontaneously during the infusions. Data were analyzed using a two-factor analysis of variance (ANOVA) with repeated measures. RESULTS Basal serum K(+) did not differ between races (African American 3.97 +/- 0.06 mEq/L and Caucasian American 3.98 +/- 0.05, P= NS). The rise in serum K(+) during the infusion and the area under the curve of serum K(+) over the 3.5 hours of observation were both greater in African American (African American +0.82 +/- 0.07 mEq/L and Caucasian American +0.61 +/- 0.06, P= 0.001; and African American 6.9 +/- 0.5 units and Caucasian American 5.1 +/- 0.6, P= 0.0012). The 10-day period of controlled intake did not abolish these differences. Aldosterone at baseline was lower and insulin was higher in African Americans at the end of the infusion. Urinary K(+), plasma glucose, and renin levels did not differ between African Americans and Caucasian Americans. CONCLUSION Disposal of an intravenous (iv) K(+) load is decreased in African Americans compared with Caucasian Americans, which may reflect decreased Na(+),K(+)-ATPase activity in African Americans in vivo.
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Affiliation(s)
- Annie Suh
- Department of Medicine, Division of Nephrology/Hypertension and Endocrinology, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611-3008, USA
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Cohen HW, Madhavan S, Alderman MH. High and low serum potassium associated with cardiovascular events in diuretic-treated patients. J Hypertens 2001; 19:1315-23. [PMID: 11446723 DOI: 10.1097/00004872-200107000-00018] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine the relationship of moderately high and low concentrations of serum potassium with cardiovascular disease events among treated hypertensive patients. DESIGN An observational cohort study with prospectively collected data. SETTING A worksite treatment program for mild hypertension. PATIENTS All program participants with baseline and at least one annual follow-up measure of serum potassium; 7,653 individuals with 6.7 years mean follow-up met these criteria. MAIN OUTCOME MEASURES Outcome events were admissions to hospital because of cardiovascular disease, and deaths. The research question regarding serum potassium categories was formulated after data collection. The serum potassium concentration (mean +/- 2SD) of the study population was used to define low (3.0-3.5 mmol/l), high (5.1-5.9 mmol/l) and middle (3.6-5.0 mmol/l) categories. RESULTS Individuals with low (n = 146) and high (n = 226) serum potassium had significantly greater risk for cardiovascular disease events than those in the middle category (n = 7,281). Multivariate adjusted hazard ratios from Cox models were 2.6 [95% confidence intervals (CI) 1.5-4.4] for the low potassium group and 1.7 (95% CI 1.0-2.7) for the high potassium group, with the middle group as reference. Among 1,679 individuals who regularly took diuretics, hazard ratios were 4.3 (95% CI 2.4-7.9) for the low potassium group and 6.7 (95% CI 2.8-15.9) for the high group. Neither low nor high potassium was significantly associated with outcome events for those not regularly using diuretics. CONCLUSIONS These data confirm an association of mild hypokalemia with increased cardiovascular events among diuretic-treated hypertensive patients. In addition, we have found a similar increased cardiovascular risk associated with modest hyperkalemia among these patients. Whether modification of these serum potassium concentrations would alter that risk remains to be determined.
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Affiliation(s)
- H W Cohen
- Department of Epidemiology and Social Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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Ray PE, Suga S, Liu XH, Huang X, Johnson RJ. Chronic potassium depletion induces renal injury, salt sensitivity, and hypertension in young rats. Kidney Int 2001; 59:1850-8. [PMID: 11318956 DOI: 10.1046/j.1523-1755.2001.0590051850.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Chronic hypokalemia has been associated with renal hypertrophy, interstitial disease, and hypertension in both adult animals and humans. However, the effects of potassium (K(+)) depletion on the rapidly growing infant have not been well studied. The purpose of this study was to determine the effects of severe chronic dietary K(+) depletion on blood pressure (BP) and renal structural changes in young rats. METHODS Sprague-Dawley rats (50 +/- 5 g) were fed either a control or a potassium-deficient diet (<0.05% K(+)) for 14 to 21 days. At the end of this period, the blood pressure (BP) was measured in all rats, and six rats in each group were sacrificed to determine changes in renal histology and renin-angiotensin system (RAS) activity. The remaining rats in each group were then switched to a high-salt (6% NaCl)--normal-K(+) (0.5%) diet or were continued on their respective control or K(+)-deficient diet for an additional six days. Blood pressure measurements were done every three days until the end of the study. RESULTS K(+)-depleted animals had significant growth retardation and increased RAS activity, manifested by high plasma renin activity, recruitment of renin-producing cells along the afferent arterioles, and down-regulation of angiotensin II receptors in renal glomeruli and ascending vasa rectae. K(+)-depleted kidneys also showed tubulointerstitial injury with tubular cell proliferation, osteopontin expression, macrophage infiltration, and early fibrosis. At week 2, K(+)-depleted rats had higher systolic BP than control rats. Switching to a high-salt (6% NaCl)--normal-K(+) diet resulted in further elevation of systolic BP in K(+)-depleted rats, which persisted even after the serum K(+) was normalized. CONCLUSION Dietary potassium deficiency per se increases the BP in young rats and induces salt sensitivity that may involve at least two different pathogenic pathways: increased RAS activity and induction of tubulointerstitial injury.
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Affiliation(s)
- P E Ray
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, Washington DC 20010, USA.
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Resnick LM, Oparil S, Chait A, Haynes RB, Kris-Etherton P, Stern JS, Clark S, Holcomb S, Hatton DC, Metz JA, McMahon M, Pi-Sunyer FX, McCarron DA. Factors affecting blood pressure responses to diet: the Vanguard study. Am J Hypertens 2000; 13:956-65. [PMID: 10981544 DOI: 10.1016/s0895-7061(00)01221-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
To study physiologic factors affecting the blood pressure (BP) response to nonpharmacologic maneuvers, fasting blood glucose, insulin, lipid and mineral levels, urinary mineral excretion, and the calcium regulating hormones parathyroid hormone (PTH) and 1,25 dihydroxyvitamin D (1,25 (OH)2D) were measured in 71 unmedicated hypertensive (26 hypertensive only [HT], 45 hypertensive hyperlipidemic [HTHL]), and 87 normotensive hyperlipidemic (NTHL) control subjects before and during a 10-week multicenter, randomized controlled trial comparing a prepared meal plan (CCNW) with a self-selected diet (SSD) based on nutritionist counseling. Blood pressure fell to a greater extent in hypertensive versus normotensive subjects (-8+/-1/-5+/-1 v -2+/-1/-2+/-1 mm Hg, P < .0001/P < .0001), and on CCNW versus SSD diets (delta systolic BP [SBP]/delta diastolic BP [DBP], P = .033/P = .002). Diet-induced weight change was the strongest correlate of changes in BP (SBP: r = 0.360, P < .0001; DBP: r = 0.414, P < .0001), which, on multivariate analysis for deltaSBP, could partly be accounted for by diet-induced changes in fasting glucose (r = 0.215, P = .009) and cholesterol (r = 0.219, P = .006) levels. Independently of weight, diet-induced changes in SBP also were significantly related to concomitant changes in urinary excretion of potassium (r = -0.285, P = .001), magnesium (r = -0.254, P = .003), and calcium relative to sodium (r = -0.200, P = .021), but not to sodium per se; and to changes in serum potassium (r = -0.249, P = .002), phosphorus (r = -0.279, P = .001), PTH (r = 0.288, P = .0006), and 1,25 D (r = 0.202, P = .017). We conclude that the ability of diet to lower BP successfully may result from the additive contributions of multiple components. Independently of weight loss and the associated changes in circulating glucose and cholesterol, BP is influenced by the increasing provision of minerals such as potassium, magnesium, and calcium, perhaps by virtue of their suppressive effects on circulating vasoactive calcium regulating hormones.
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Affiliation(s)
- L M Resnick
- Hypertension Center, New York-Presbyterian Hospital/Cornell University Medical Center, New York 10021, USA
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Sorof JM, Forman A, Cole N, Jemerin JM, Morris RC. Potassium intake and cardiovascular reactivity in children with risk factors for essential hypertension. J Pediatr 1997; 131:87-94. [PMID: 9255197 DOI: 10.1016/s0022-3476(97)70129-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Our study objectives were as follows: (1) to determine whether urinary excretion of potassium is lower in black than in white children, (2) to determine whether cardiovascular reactivity (CVR) varies inversely with dietary intake of potassium, and (3) to confirm that CVR is greater in black than in white children, and in children with a family history of hypertension than in those without such a history. STUDY DESIGN Baseline measurements included 24-hour urinary sodium, potassium, and creatinine levels and food intake (by questionnaire). Resting and stress blood pressure were measured during blood sampling, cold water foot immersion, and a video game before and after 1 week each of supplementation with potassium citrate, 1.5 mmol/kg per day, and placebo administered in random order. RESULTS Thirty-nine children aged 7 to 15 years were studied. White subjects had higher baseline excretion of potassium than black subjects (p < 0.001) and higher vegetable intake (p < 0.01), which were positively correlated (r = 0.53, p < 0.001). At baseline, the 24-hour urinary potassium/creatinine ratio varied inversely with diastolic CVR to the video game stressor in white children (r = -0.55, p = 0.02). Cardiovascular reactivity was not attenuated measurably by potassium supplementation compared with placebo. The CVR was greater in children with a family history of hypertension than in those without, but was not greater in black children than in white children. CONCLUSIONS The urinary potassium/creatinine ratio is higher in white than black children because their intake of vegetables is greater; dietary potassium intake may modulate CVR, particularly in white children with a family history of hypertension, but may need to be supplemented for more than 1 week to demonstrate attenuation of CVR; and a family history of hypertension may be a stronger predictor of enhanced CVR than is race.
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Affiliation(s)
- J M Sorof
- Department of Pediatrics, University of California-San Francisco, USA
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Abstract
We conducted this study to determine whether physiological changes in potassium concentration affect free radical formation by vascular cells. We assessed the effects of potassium on reactive oxygen species formed by cultured endothelial and monocyte/macrophage cells or freshly isolated human white blood cells by cytochrome c reduction or luminol chemiluminescence, respectively. Reducing potassium concentration of endothelial cell media (normally 5.1 to 6.1 mmol/L) to 3.0 mmol/L exponentially increased the rate of cytochrome c reduction, up to 8.4-fold at 2 hours; raising potassium concentration to 5.5 or 7.0 mmol/L at 1 hour reduced the maximal rate of cytochrome c reduction by 86% or 93%. Subsequent studies were done 30 to 75 minutes after media change. Potassium reduced the rate of cytochrome c reduction by 49% (endothelial cells) to 55% (monocytes/macrophages) between 3.0 and 7.0 mmol/L; the greatest decrement (20% to 26%) occurred between 3.0 and 4.0 mmol/L. Superoxide dismutase reduced the rate of cytochrome c reduction by 62% or 50% in endothelial or monocyte/macrophage cells. Potassium had no effect on the rate of cytochrome c reduction in the presence of superoxide dismutase. Increasing potassium concentration from 1.48 to 4.77 or 7.94 mmol/L also reduced luminol chemiluminescence in human white blood cells challenged by 1 to 10 mg/mL zymosan. We conclude that physiological increases in potassium concentration inhibit the rate of superoxide anion formation by cell lines derived from endothelium and from monocytes/macrophages and reactive oxygen species formation by human white blood cells.
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Affiliation(s)
- R D McCabe
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson 39216-4505
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