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Strauss-Kruger M, Pieters M, van Zyl T, Gafane-Matemane LF, Mokwatsi GG, Jacobs A, Schutte AE, Louw R, Mels CM. Metabolomic Insights on Potassium Excretion, Blood Pressure, and Glucose Homeostasis: The African-PREDICT Study. J Nutr 2024; 154:435-445. [PMID: 38110181 DOI: 10.1016/j.tjnut.2023.12.025] [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: 08/14/2023] [Revised: 11/09/2023] [Accepted: 12/14/2023] [Indexed: 12/20/2023] Open
Abstract
BACKGROUND Low-potassium intake is associated with a higher risk of type 2 diabetes and hypertension. Both conditions occur more frequently in Black populations, who also consume less potassium-rich foods. OBJECTIVES Using metabolomics to identify dysregulated metabolic pathways associated with low-potassium excretion may procure more accurate entry points for nutritional prevention and intervention for type 2 diabetes and hypertension. METHODS A total of 440 White and 350 Black adults from the African-PREDICT study (aged 20-30 y) were included. Twenty-four-hour blood pressure (BP) was measured. Potassium, sodium, and fasting glucose concentrations were analyzed in 24-h urine and plasma samples. Liquid chromatography-tandem mass spectrometry-based metabolomics included the analyses of amino acids and acylcarnitines in spot urine samples. RESULTS Black participants had lower urinary potassium concentrations than Whites (36.6 compared with 51.1 mmol/d; P < 0.001). In White but not Black adults, urinary potassium correlated positively with 2-aminoadipic acid (2-AAA) (r = 0.176), C3-[propionyl]carnitine (r = 0.137), C4-[butyryl]carnitine (r = 0.169) and C5-[isovaleryl]carnitine (r = 0.167) in unadjusted and 2-AAA (r = 0.158) and C4-carnitine (r = 0.160) in adjusted analyses (all P < 0.05 and q < 0.05). Elevated C0-, C3-, and C5-carnitine in turn were positively associated with systolic BP (Black and White groups), diastolic BP (Black group), and glucose (White group) (all P < 0.05). CONCLUSIONS Racial differences are an important consideration when investigating nutrient-metabolite relationships and the role thereof in cardiovascular disease. Only in White adults did urinary potassium associate with 2-AAA and short-chain acylcarnitines. These metabolites were positively related to BP and fasting plasma glucose concentrations. In White adults, the metabolomic profiles related to potassium excretion may contribute to BP regulation and glucose homeostasis. This trial was registered at clinicaltrials.gov as NCT03292094.
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Affiliation(s)
- Michél Strauss-Kruger
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, North-West Province, South Africa; MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa
| | - Marlien Pieters
- MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa; Centre of Excellence for Nutrition (CEN), North-West University, Potchefstroom, North-West Province, South Africa
| | - Tertia van Zyl
- MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa; Centre of Excellence for Nutrition (CEN), North-West University, Potchefstroom, North-West Province, South Africa
| | - Lebo F Gafane-Matemane
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, North-West Province, South Africa; MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa
| | - Gontse G Mokwatsi
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, North-West Province, South Africa; MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa
| | - Adriaan Jacobs
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, North-West Province, South Africa; MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa
| | - Aletta E Schutte
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, North-West Province, South Africa; MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa; School of Population Health, University of New South Wales, Sydney, New South Wales, Australia; The George Institute for Global Health, Sydney, New South Wales, Australia
| | - Roan Louw
- Human Metabolomics, North-West University, Potchefstroom, North-West Province, South Africa
| | - Catharina Mc Mels
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, North-West Province, South Africa; MRC Extramural Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, North-West Province, South Africa.
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Shokunbi OS, Adepoju OT, Ramaite IDI, Shokunbi OS, Mojapelo PEL, Akinyele IO. Potassium, sodium, calcium and magnesium levels of commonly consumed foods and estimates of dietary intakes of selected Nigerian adults. Heliyon 2023; 9:e13729. [PMID: 36873486 PMCID: PMC9981908 DOI: 10.1016/j.heliyon.2023.e13729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Micronutrient deficiency is a public health challenge globally, as it affects both people and the economy. In Nigeria, most micronutrients, especially minerals are lost during food processing. The study was carried out to determine the potassium, sodium, calcium and magnesium composition of foods commonly eaten by Nigerian adults and to estimate the average adults' daily intake of these macrominerals. The contents of these minerals in 141 food items collected 'as consumed' from 10 locations in Federal Capital Territory, Abuja and Ogun State, Nigeria, were quantified by digesting the foods through dry ashing and analysed using flame atomic absorption spectrometer. The levels (mg/100 g fresh weight) of potassium, sodium, calcium and magnesium in the various foods ranged from 2.92 to 1520, 1.46 to 30,700, 1.35 to 1280 and 1.16 to 416, respectively. Recovery values were within the range of 95-110%. Adults' mean mineral intakes (mg/person/day) of the analysed foods were 1970 ± 780, 2750 ± 1100, 423 ± 300 and 389 ± 130 for potassium, sodium, calcium and magnesium, respectively. Mean sodium intake was higher while potassium and calcium intakes were lower compared with international recommendations (mg/person/day) of 1500, 2300-3400 and 1000-1300, respectively; indicating the need to enlighten consumers. The snapshot data from this study are useful to update the Nigerian Food Composition Database.
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Affiliation(s)
- Olutayo Sunday Shokunbi
- Department of Chemistry, School of Mathematical and Natural Sciences, University of Venda, Limpopo Province, South Africa.,Department of Human Nutrition and Dietetics, Faculty of Public Health, College of Medicine, University of Ibadan, Ibadan, Nigeria.,Department of Biochemistry, School of Basic Medical Sciences, Babcock University, Ilishan-Remo, Ogun State, Nigeria
| | - Oladejo Thomas Adepoju
- Department of Human Nutrition and Dietetics, Faculty of Public Health, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Isaiah David Ipfani Ramaite
- Department of Chemistry, School of Mathematical and Natural Sciences, University of Venda, Limpopo Province, South Africa
| | - Oluwatosin Sarah Shokunbi
- Department of Basic Sciences, School of Science and Technology, Babcock University, Ilishan-Remo, Ogun State, Nigeria
| | - Paul Eanas Lesedi Mojapelo
- Department of Chemistry, School of Mathematical and Natural Sciences, University of Venda, Limpopo Province, South Africa
| | - Isaac Olaolu Akinyele
- Department of Human Nutrition and Dietetics, Faculty of Public Health, College of Medicine, University of Ibadan, Ibadan, Nigeria
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Effect of Potassium Supplementation on Endothelial Function: A Systematic Review and Meta-Analysis of Intervention Studies. Nutrients 2023; 15:nu15040853. [PMID: 36839211 PMCID: PMC9961878 DOI: 10.3390/nu15040853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
(1) Background: Endothelial dysfunction is an early predictor of cardiovascular diseases. Although a large body of evidence shows an inverse association between potassium intake and cardiovascular risk, the studies on endothelial function provided contrasting results. Thus, we carried out a systematic review and a meta-analysis of the available intervention studies of the potassium supplementation on endothelial function. (2) Methods: A systematic search of the online databases available (up to December 2022) was conducted including the intervention trials that reported flow-mediated dilation (FMD) changes-a non-invasive method of assessing endothelial function-after two different potassium intake regimens. For each study, the mean difference (MD) and 95% confidence intervals were pooled using a random effect model. (3) Results: Five studies met the pre-defined inclusion criteria and provided eight cohorts with 332 participants. In the pooled analysis, potassium supplementation was associated with a significant increase in FMD (MD: 0.74%), with a higher effect for a urinary potassium excretion higher than 90 mmol/day. There was a moderate heterogeneity among studies (I2 = 59%), explained by the different amount of potassium supplementation. (4) Conclusions: The results of our meta-analysis indicate that dietary potassium supplement improves endothelial function. This effect is directly associated with the amount of potassium supplement. The findings support the campaigns in favour of an increase in dietary potassium intake to reduce cardiovascular risk.
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Schaffer S, Rimbach G, Pieper D, Hommen N, Fischer A, Birringer M, Seidel U. Minerals and Trace Elements in 990 Beverages and Their Contribution to Dietary Reference Values for German Consumers. Nutrients 2022; 14:nu14224899. [PMID: 36432585 PMCID: PMC9697264 DOI: 10.3390/nu14224899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/10/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Beverages are an integral part of human nutrition, yet little is known about their contribution to daily intakes of minerals and trace elements in German consumers. Using inductively coupled plasma-mass spectrometry, we determined the concentration of five minerals and six trace elements in beverage samples (n = 990, assigned to different beverage groups) collected throughout Germany. For a calculation of their relative contribution to the mineral supply, available beverage consumption data was combined with our quantitative analysis to calculate the average contribution of beverage groups to meet the respective dietary reference values currently used in Germany, Austria and Switzerland (D-A-CH region). Based on their presence in beverages and their consumption, the top three minerals are phosphorous, calcium and magnesium, and they, therefore, may reasonably contribute to the reference values. Among the trace elements, beverages mostly contributed to the manganese supply, whereas at the same time, concentrations of iron, cobalt and copper were low across all tested groups. Our study provides an overview of the assumed mineral and trace element intake via beverages in Germany and may, thus, serve as a foundation for a mineral and trace element database of beverages that needs to be expanded in the future.
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Affiliation(s)
- Sebastian Schaffer
- Institute of Human Nutrition and Food Science, University of Kiel, 24118 Kiel, Germany
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science, University of Kiel, 24118 Kiel, Germany
| | - David Pieper
- Institute of Human Nutrition and Food Science, University of Kiel, 24118 Kiel, Germany
| | - Niklas Hommen
- Institute of Human Nutrition and Food Science, University of Kiel, 24118 Kiel, Germany
| | - Alexandra Fischer
- Institute of Human Nutrition and Food Science, University of Kiel, 24118 Kiel, Germany
| | - Marc Birringer
- Department of Nutritional, Food and Consumer Sciences, University of Applied Sciences Fulda, 36037 Fulda, Germany
| | - Ulrike Seidel
- Institute of Human Nutrition and Food Science, University of Kiel, 24118 Kiel, Germany
- Correspondence: ; Tel.: +49-431-880-5334
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Britto DT, Coskun D, Kronzucker HJ. Potassium physiology from Archean to Holocene: A higher-plant perspective. JOURNAL OF PLANT PHYSIOLOGY 2021; 262:153432. [PMID: 34034042 DOI: 10.1016/j.jplph.2021.153432] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/22/2021] [Accepted: 04/22/2021] [Indexed: 05/27/2023]
Abstract
In this paper, we discuss biological potassium acquisition and utilization processes over an evolutionary timescale, with emphasis on modern vascular plants. The quintessential osmotic and electrical functions of the K+ ion are shown to be intimately tied to K+-transport systems and membrane energization. Several prominent themes in plant K+-transport physiology are explored in greater detail, including: (1) channel mediated K+ acquisition by roots at low external [K+]; (2) K+ loading of root xylem elements by active transport; (3) variations on the theme of K+ efflux from root cells to the extracellular environment; (4) the veracity and utility of the "affinity" concept in relation to transport systems. We close with a discussion of the importance of plant-potassium relations to our human world, and current trends in potassium nutrition from farm to table.
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Affiliation(s)
- Dev T Britto
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Devrim Coskun
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation (FSAA), Université Laval, Québec, QC, G1V 0A6, Canada
| | - Herbert J Kronzucker
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia.
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Stone MS, Martin BR, Weaver CM. Short-Term RCT of Increased Dietary Potassium from Potato or Potassium Gluconate: Effect on Blood Pressure, Microcirculation, and Potassium and Sodium Retention in Pre-Hypertensive-to-Hypertensive Adults. Nutrients 2021; 13:1610. [PMID: 34064968 PMCID: PMC8151047 DOI: 10.3390/nu13051610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 01/04/2023] Open
Abstract
Increased potassium intake has been linked to improvements in cardiovascular and other health outcomes. We assessed increasing potassium intake through food or supplements as part of a controlled diet on blood pressure (BP), microcirculation (endothelial function), and potassium and sodium retention in thirty pre-hypertensive-to-hypertensive men and women. Participants were randomly assigned to a sequence of four 17 day dietary potassium treatments: a basal diet (control) of 60 mmol/d and three phases of 85 mmol/d added as potatoes, French fries, or a potassium gluconate supplement. Blood pressure was measured by manual auscultation, cutaneous microvascular and endothelial function by thermal hyperemia, utilizing laser Doppler flowmetry, and mineral retention by metabolic balance. There were no significant differences among treatments for end-of-treatment BP, change in BP over time, or endothelial function using a mixed-model ANOVA. However, there was a greater change in systolic blood pressure (SBP) over time by feeding baked/boiled potatoes compared with control (-6.0 mmHg vs. -2.6 mmHg; p = 0.011) using contrast analysis. Potassium retention was highest with supplements. Individuals with a higher cardiometabolic risk may benefit by increasing potassium intake. This trial was registered at ClinicalTrials.gov as NCT02697708.
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Affiliation(s)
| | | | - Connie M. Weaver
- Nutrition Science, Purdue University, West Lafayette, IN 47907, USA; (M.S.S.); (B.R.M.)
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Ballová ZK, Korec F, Pinterová K. Relationship between heavy metal accumulation and histological alterations in voles from alpine and forest habitats of the West Carpathians. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:36411-36426. [PMID: 32562226 DOI: 10.1007/s11356-020-09654-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
The interaction between toxic heavy metals and bio-elements in internal organs and femoral bones and their potential impacts on bone structural properties and renal histopathological changes in bank voles and snow voles were investigated. Our results reveal that heavy metals Hg and Pb accumulate more in femoral bones of alpine habitats than forests. In snow voles, the parameters of the primary osteons' vascular canals (length, average perimeter and area) simultaneously decreased with an increase of Pb and Sr. Wider primary osteons' vascular canals of snow voles contained decreased levels of K, but increased Ba. In bank voles, the number of primary osteons increased in alpine habitats along with K, Hg, and Pb accumulation. In the kidneys of bank voles, rising levels of Rb, Hg, and Zn were detected in alpine habitats. Hg increases the most in kidney tissue from alpine habitats in both vole species, and Hg levels (mean value 0.25 μg/g, max. value 0.55 μg/g) in the renal tissues of bank voles from alpine localities are similar to Hg levels from Hg-polluted industrial areas in other studies. This reflects that alpine areas of the Tatra Mountains are highly contaminated with Hg. The intensity of renal hemosiderosis relates significantly to Zn, Fe, and Cu levels in snow voles, with Fe and Zn levels in bank voles from forest habitats, and with Rb in bank voles from alpine habitats. The intensity of tubule necrosis in renal tissues of bank voles from alpine habitats was negatively related to Se content. In bank voles from forest habitats, significant positive correlations were found between the intensity of glomerular hyperplasia and amounts of Zn. The interactions of the detected element's association with bone tissue and internal organs are discussed.
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Affiliation(s)
- Zuzana Kompišová Ballová
- Institute of High Mountain Biology, University of Žilina, Tatranská Javorina 7, SK-05956, Tatranská Javorina, Slovakia.
| | - Filip Korec
- Institute of High Mountain Biology, University of Žilina, Tatranská Javorina 7, SK-05956, Tatranská Javorina, Slovakia
| | - Katarína Pinterová
- Institute of High Mountain Biology, University of Žilina, Tatranská Javorina 7, SK-05956, Tatranská Javorina, Slovakia
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Schiefermeier-Mach N, Egg S, Erler J, Hasenegger V, Rust P, König J, Purtscher AE. Electrolyte Intake and Major Food Sources of Sodium, Potassium, Calcium and Magnesium among a Population in Western Austria. Nutrients 2020; 12:nu12071956. [PMID: 32630029 PMCID: PMC7400604 DOI: 10.3390/nu12071956] [Citation(s) in RCA: 2] [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: 05/12/2020] [Revised: 06/24/2020] [Accepted: 06/28/2020] [Indexed: 12/11/2022] Open
Abstract
Dietary intake of sodium, potassium, calcium and magnesium has a strong impact on personal health. In order to understand possible correlations with regional occurrence of diseases and to develop new dietary strategies, it is necessary to evaluate food choices in defined geographic areas. The aim of this study was to analyze daily consumption and major food sources of electrolytes with an emphasis on dietary patterns. In this representative, cross-sectional study, daily foods of 463 adults were assessed with two nonconsecutive 24-h recalls. Our results show high sodium and low potassium consumption in all age groups in both men and women. Furthermore, more than half of investigated persons had low calcium, and 40% indicated low dietary magnesium intake. Only 1% of our study population reached the recommended values for all electrolytes, while 13% consumed adequate levels of three electrolytes. Moreover, 14% did not reach reference levels for any of the four minerals. A further comparison of dietary patterns and food preferences showed significant differences in major food groups including nonalcoholic drinks, fruits, vegetables, legumes, milk products, vegetable oil, bread and sweets. Our results are important for further evaluations of nutrition intake and the development of new dietary strategies.
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Affiliation(s)
- Natalia Schiefermeier-Mach
- Department of Health Care and Nursing, FH Gesundheit, Health University of Applied Sciences Tyrol, 6020 Innsbruck, Austria;
| | - Sabrina Egg
- Department of Dietetics, FH Gesundheit, Health University of Applied Sciences Tyrol, 6020 Innsbruck, Austria; (S.E.); (J.E.)
| | - Judith Erler
- Department of Dietetics, FH Gesundheit, Health University of Applied Sciences Tyrol, 6020 Innsbruck, Austria; (S.E.); (J.E.)
| | - Verena Hasenegger
- Department of Nutritional Sciences, University of Vienna, 1090 Vienna, Austria; (V.H.); (P.R.); (J.K.)
| | - Petra Rust
- Department of Nutritional Sciences, University of Vienna, 1090 Vienna, Austria; (V.H.); (P.R.); (J.K.)
| | - Jürgen König
- Department of Nutritional Sciences, University of Vienna, 1090 Vienna, Austria; (V.H.); (P.R.); (J.K.)
| | - Anna Elisabeth Purtscher
- Department of Dietetics, FH Gesundheit, Health University of Applied Sciences Tyrol, 6020 Innsbruck, Austria; (S.E.); (J.E.)
- Correspondence: ; Tel.: +43-512-5322-76738
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Abstract
Hypertension is the leading cause of cardiovascular disease and premature death worldwide. Owing to the widespread use of antihypertensive medications, global mean blood pressure (BP) has remained constant or has decreased slightly over the past four decades. By contrast, the prevalence of hypertension has increased, especially in low- and middle-income countries (LMICs). Estimates suggest that 31.1% of adults (1.39 billion) worldwide had hypertension in 2010. The prevalence of hypertension among adults was higher in LMICs (31.5%, 1.04 billion people) than in high-income countries (28.5%, 349 million people). Variations in the levels of risk factors for hypertension, such as high sodium intake, low potassium intake, obesity, alcohol consumption, physical inactivity and unhealthy diet, may explain some of the regional heterogeneity in hypertension prevalence. Despite the increasing prevalence, the proportions of hypertension awareness, treatment and BP control are low, particularly in LMICs, and few comprehensive assessments of the economic impact of hypertension exist. Future studies are warranted to test implementation strategies for hypertension prevention and control, especially in low-income populations, and to accurately assess the prevalence and financial burden of hypertension worldwide.
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Affiliation(s)
- Katherine T Mills
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Tulane University Translational Sciences Institute, New Orleans, LA, USA
| | - Andrei Stefanescu
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Jiang He
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA.
- Tulane University Translational Sciences Institute, New Orleans, LA, USA.
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Hoorn EJ, Gritter M, Cuevas CA, Fenton RA. Regulation of the Renal NaCl Cotransporter and Its Role in Potassium Homeostasis. Physiol Rev 2020; 100:321-356. [DOI: 10.1152/physrev.00044.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Daily dietary potassium (K+) intake may be as large as the extracellular K+ pool. To avoid acute hyperkalemia, rapid removal of K+ from the extracellular space is essential. This is achieved by translocating K+ into cells and increasing urinary K+ excretion. Emerging data now indicate that the renal thiazide-sensitive NaCl cotransporter (NCC) is critically involved in this homeostatic kaliuretic response. This suggests that the early distal convoluted tubule (DCT) is a K+ sensor that can modify sodium (Na+) delivery to downstream segments to promote or limit K+ secretion. K+ sensing is mediated by the basolateral K+ channels Kir4.1/5.1, a capacity that the DCT likely shares with other nephron segments. Thus, next to K+-induced aldosterone secretion, K+ sensing by renal epithelial cells represents a second feedback mechanism to control K+ balance. NCC’s role in K+ homeostasis has both physiological and pathophysiological implications. During hypovolemia, NCC activation by the renin-angiotensin system stimulates Na+ reabsorption while preventing K+ secretion. Conversely, NCC inactivation by high dietary K+ intake maximizes kaliuresis and limits Na+ retention, despite high aldosterone levels. NCC activation by a low-K+ diet contributes to salt-sensitive hypertension. K+-induced natriuresis through NCC offers a novel explanation for the antihypertensive effects of a high-K+ diet. A possible role for K+ in chronic kidney disease is also emerging, as epidemiological data reveal associations between higher urinary K+ excretion and improved renal outcomes. This comprehensive review will embed these novel insights on NCC regulation into existing concepts of K+ homeostasis in health and disease.
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Affiliation(s)
- Ewout J. Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Martin Gritter
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Catherina A. Cuevas
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Robert A. Fenton
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
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