Associations between serum potassium and sodium levels and risk of hypertension: a community-based cohort study

Macrophage SPAK deletion limits a low potassium-induced kidney inflammatory program

Inadequate dietary potassium (K+) consumption is a significant contributor to poor cardiovascular outcomes. A diet with reduced K+ content has been shown to cause salt-sensitive increases in blood pressure. More recently, we have also shown that reductions in blood K+ can cause direct kidney injury, independent of dietary sodium (Na+) content. Here, we investigated the role of the kinase Ste20p-related proline-alanine-rich kinase (SPAK) in this kidney injury response. We observed that global SPAK deletion protected the kidney from the damaging effects of a diet high in Na+ and low in K+. We hypothesized that kidney macrophages were contributing to the injury response and that macrophage-expressed SPAK is essential in this process. We observed SPAK protein expression in isolated macrophages in vitro. Culture in K+-deficient medium increased SPAK phosphorylation and caused SPAK to localize to cytosolic puncta, reminiscent of with-no-lysine kinase (WNK) bodies identified along the distal nephron epithelium. WNK1 also adopted a punctate staining pattern under low K+ conditions, and SPAK phosphorylation was prevented by treatment with the WNK inhibitor WNK463. Macrophage-specific SPAK deletion in vivo protected against the low K+-mediated renal inflammatory and fibrotic responses. Our results highlight an important role for macrophages and macrophage-expressed SPAK in the propagation of kidney damage that occurs in response to reduced dietary K+ consumption.NEW & NOTEWORTHY Global Ste20p-related proline alanine-rich kinase (SPAK) deletion protects against harmful kidney effects of dietary K+ deficiency. Exposure to low K+ conditions increases SPAK phosphorylation and induces SPAK to adopt a punctate staining pattern. Macrophage-specific deletion of SPAK confers protection to low K+-induced kidney injury in vivo. Macrophage-expressed SPAK plays a key role in the development of kidney injury in response to a low K+ diet.

Prediction Tool to Estimate Potassium Diet in Chronic Kidney Disease Patients Developed Using a Machine Learning Tool: The UniverSel Study

There is a need for a reliable and validated method to estimate dietary potassium intake in chronic kidney disease (CKD) patients to improve prevention of cardiovascular complications. This study aimed to develop a clinical tool to estimate potassium intake using 24-h urinary potassium excretion as a surrogate of dietary potassium intake in this high-risk population. Data of 375 adult CKD-patients routinely collecting their 24-h urine were included to develop a prediction tool to estimate potassium diet. The prediction tool was built from a random sample of 80% of patients and validated on the remaining 20%. The accuracy of the prediction tool to classify potassium diet in the three classes of potassium excretion was 74%. Surprisingly, the variables related to potassium consumption were more related to clinical characteristics and renal pathology than to the potassium content of the ingested food. Artificial intelligence allowed to develop an easy-to-use tool for estimating patients' diets in clinical practice. After external validation, this tool could be extended to all CKD-patients for a better clinical and therapeutic management for the prevention of cardiovascular complications.

Serum sodium and risk of hypertension: a cohort study

This study aimed to investigate the cross-sectional association between serum sodium and blood pressure at baseline and, more importantly, investigate the prospective association between serum sodium and the risk of incident hypertension. We used data from 1 638 workers aged 18 to 71 years who participated in 2015-2016 survey of the Furukawa Nutrition and Health Study. During a maximum follow-up of 3 years, 229 participants developed hypertension. Multivariable linear regression models were used to evaluate the cross-sectional association. The Cox proportional hazards model was used to calculate the hazard ratio and 95% confidence interval of incident hypertension across quartiles of serum sodium (137-140, 141-142, 143, and 144-147 mmol/L). In the cross-sectional analysis, we did not observe a significant association between serum sodium and blood pressure at baseline. In the prospective analysis, the multivariable-adjusted hazard ratios (95% confidence intervals) for incident hypertension were 1.03 (0.71-1.51), 1.35 (0.87-2.08), and 1.46 (0.97-2.20) for the upper three quartiles of the serum sodium levels compared with the lowest quartile (P for trend=0.02). When serum sodium was treated as a continuous variable, the multivariable-adjusted hazard ratio for hypertension was 1.10 (1.03-1.18). The association was slightly attenuated after additionally adjusting for baseline blood pressure, with a hazard ratio of 1.08 (1.00-1.16) for a 1 mmol/L increase in serum sodium. In conclusion, an elevated serum sodium level was associated with an increased risk of developing hypertension, suggesting that serum sodium could be a potential risk factor for hypertension.

Impact of Micronutrients on Hypertension: Evidence from Clinical Trials with a Special Focus on Meta-Analysis

Hypertension (HT) is one of the pivotal risk factors for various detrimental diseases like cardiovascular diseases (CVDs), cerebrovascular disease, and renal dysfunction. Currently, many researchers are paying immense attention to various diet formula (dietary approach) with a special focus on micro and macronutrients along with modified lifestyle and standard anti-hypertensive drugs. Micronutrients (minerals/vitamins) play a central role in the regulation of blood pressure (BP) as they aid the function of macronutrients and also improve the anti-hypertensive functions of some anti-hypertensive agents. Even though several studies have demonstrated the beneficial effects of micronutrients on controlling BP, still some ambiguity exists among the nutritionists/doctors, which combination or individual mineral (dietary approach) contributes to better BP regulation. Therefore, this critical review article was attempted to delineate the underlying role of micronutrients (minerals and vitamins) for the management and prevention or delaying of HT and their related complications with strong affirmation from clinical trials as well as its mechanism of controlling BP. Moreover, the major source and recommended daily allowance (RDA) of various micronutrients are included in this review for guiding common readers (especially HT subjects) and dieticians to choose/recommend a better micronutrient and their combinations (other nutrients and standard anti-hypertensive drugs) for lowering the risk of HT and its related co-morbid conditions like CVDs.

Potassium Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials

Background

Epidemiologic studies, including trials, suggest an association between potassium intake and blood pressure (BP). However, the strength and shape of this relationship is uncertain.

Methods and Results

We performed a meta‐analysis to explore the dose‐response relationship between potassium supplementation and BP in randomized‐controlled trials with a duration ≥4 weeks using the recently developed 1‐stage cubic spline regression model. This model allows use of trials with at least 2 exposure categories. We identified 32 eligible trials. Most were conducted in adults with hypertension using a crossover design and potassium supplementation doses that ranged from 30 to 140 mmol/d. We observed a U‐shaped relationship between 24‐hour active and control arm differences in potassium excretion and BP levels, with weakening of the BP reduction effect above differences of 30 mmol/d and a BP increase above differences ≈80 mmol/d. Achieved potassium excretion analysis also identified a U‐shaped relationship. The BP‐lowering effects of potassium supplementation were stronger in participants with hypertension and at higher levels of sodium intake. The BP increase with high potassium excretion was noted in participants with antihypertensive drug‐treated hypertension but not in their untreated counterparts.

Conclusions

We identified a nonlinear relationship between potassium intake and both systolic and diastolic BP, although estimates for BP effects of high potassium intakes should be interpreted with caution because of limited availability of trials. Our findings indicate an adequate intake of potassium is desirable to achieve a lower BP level but suggest excessive potassium supplementation should be avoided, particularly in specific subgroups.

Identification of calcium, sodium, magnesium and chloride ion levels in hypertensive and non-hypertensive trinidadians

Hypertension is a progressive cardiovascular disease with association to risk factors. These risk factors in conjunction with essential elements has become identifiable with the development of the progressive disease. The key purpose of this investigation was to identify the levels of the essential elements, Sodium (Na⁺), Magnesium (Mg²⁺), Chloride (Cl^-) and Calcium (Ca²⁺) in both hypertensive and non-hypertensive patients in a Trinidadian population. To achieve this objective a case-control investigation was conducted in which both hypertensive and non-hypertensive patients were assessed. Patients were issued a questionnaire with a series of open-ended questions related to the study. Blood was then drawn from each patient once consent was obtained and sent to the lab to be assayed for the elements. Fifty hypertensive (50) patients were compared with 50 non-hypertensive patients. The average levels obtained for Na⁺, Cl^-, Ca²⁺ and Mg²⁺ were 162.08±4.27 mmol/dL (P=0.53), 120.1±58.31 mmol/dL (P=0.51), 2.78±0.86 mmol/dL (P=0.47) and 0.52±0.31 mmol/dL (P<0.001) respectively for the hypertensive patients. The results in the present study revealed higher levels of Na⁺, Ca²⁺ and Cl^- and lower levels of Mg²⁺ in the hypertensive patients. The hypertensive patients were also identifiable with having high cholesterol, type 2 diabetes, and cardiovascular conditions. Sixty-two (62%) of the hypertensive patients lived with the condition for more than 10 years. The results obtained for the Trinidadian population revealed in conclusion that hypertensive patients have higher levels of Na⁺, Ca²⁺ and Cl^- and lower levels of Mg²⁺. These results are similar to the global results with small differences in their average level of each ion identified.

Meta-Analysis of Potassium Intake and the Risk of Stroke

Background

The possibility that lifestyle factors such as diet, specifically potassium intake, may modify the risk of stroke has been suggested by several observational cohort studies, including some recent reports. We performed a systematic review and meta‐analysis of existing studies and assessed the dose–response relation between potassium intake and stroke risk.

Methods and Results

We reviewed the observational cohort studies addressing the relation between potassium intake, and incidence or mortality of total stroke or stroke subtypes published through August 6, 2016. We carried out a meta‐analysis of 16 cohort studies based on the relative risk (RR) of stroke comparing the highest versus lowest intake categories. We also plotted a pooled dose–response curve of RR of stroke according to potassium intake. Analyses were performed with and without adjustment for blood pressure. Relative to the lowest category of potassium intake, the highest category of potassium intake was associated with a 13% reduced risk of stroke (RR=0.87, 95% CI 0.80–0.94) in the blood pressure–adjusted analysis. Summary RRs tended to decrease when original estimates were unadjusted for blood pressure. Analysis for stroke subtypes yielded comparable results. In the spline analysis, the pooled RR was lowest at 90 mmol of potassium daily intake (RRs=0.78, 95% CI 0.70–0.86) in blood pressure–adjusted analysis, and 0.67 (95% CI 0.57–0.78) in unadjusted analysis.

Conclusions

Overall, this dose–response meta‐analysis confirms the inverse association between potassium intake and stroke risk, with potassium intake of 90 mmol (≈3500 mg)/day associated with the lowest risk of stroke.