Blood pressure response to potassium supplementation is associated with genetic variation in endothelin 1 and interactions with E selectin in rural Chinese

Advances in Genomics Research of Blood Pressure Responses to Dietary Sodium and Potassium Intakes

More than half of US adults have hypertension by 40 years of age and a subsequent increase in atherosclerotic cardiovascular disease risk. Dietary sodium and potassium are intricately linked to the pathophysiology of hypertension. However, blood pressure responses to dietary sodium and potassium, phenomena known as salt and potassium sensitivity of blood pressure, respectively, are heterogenous and normally distributed in the general population. Like blood pressure, salt and potassium sensitivity are complex phenotypes, and previous research has shown that up to 75% of individuals experience a blood pressure change in response to such dietary minerals. Previous research has also implicated both high salt sensitivity and low salt sensitivity (or salt resistance) of blood pressure to an increased risk of hypertension and potentially atherosclerotic cardiovascular disease risk. Given the clinical challenges required to accurately measure the sodium and potassium response phenotypes, genomic characterization of these traits has become of interest for hypertension prevention initiatives on both the individual and population levels. Here, we review advances in human genomics research of blood pressure responses to dietary sodium and potassium by focusing on 3 main areas, including the phenotypic characterization of salt sensitivity and resistance, clinical challenges in diagnosing such phenotypes, and the genomic mechanisms that may help to explain salt and potassium sensitivity and resistance. Through this process, we hope to further underline the value of leveraging genomics and broader multiomics for characterizing the blood pressure response to sodium and potassium to improve precision in lifestyle approaches for primordial and primary atherosclerotic cardiovascular disease prevention.

Association between blood pressure and dietary intakes of sodium and potassium among US adults using quantile regression analysis NHANES 2007-2014

Hypertension has become a major public health challenge, and previous studies have observed associations between hypertension and sodium, potassium, and sodium to potassium ratio. However, little is known about how the whole continuum of blood pressure (BP) is related to dietary intake of sodium and potassium. This study aims to examine quantile-specific associations of blood pressure with dietary intake of sodium and potassium. It is based on national-level, cross sectional data for US adults aged ≥18 years from the National Health and Nutrition Examination Survey (NHANES) 2007-2014. A total of 11,095 eligible subjects were included in this study. Quantile regression (QR) models were used to investigate distributional effects in the dietary intake of sodium and potassium on blood pressure by adjusting the confounding factors. We observed some evidence indicating distributional effects of dietary intake of sodium and potassium on systolic blood pressure (SBP) and diastolic blood pressure (DBP). QR showed that the consumption of sodium was positively associated with SBP (P₁₀) and DBP (P₁₀) in males, and positively associated with DBP (P₈₀-P₉₀) alone in females. Intake of potassium was, however, negatively associated with SBP (P₂₀-P₃₀, P₇₀-P₈₀) in males, and also negatively associated with SBP (P₁₀-P₈₀) and DBP(P₂₀-P₅₀) in females. Sodium to potassium ratio was positively associated with SBP (P₁₀-P₅₀, P₈₀) and DBP (P₇₀-P₉₀) in males, and was positively associated with SBP(P₁₀-P₇₀, P₉₀) in females. QR models provided a more detailed view on associations of SBP and DBP with the dietary intake of sodium and potassium and uncovered the quantile-related patterns.

Genetic variants in adiponectin and blood pressure responses to dietary sodium or potassium interventions: a family-based association study

Previous studies have shown that genetic factors might have an important role in blood pressure (BP) responses to dietary salt or potassium intake. The aim of this study was to assess the association of common genetic variants of the adiponectin gene with BP responses to controlled dietary sodium or potassium interventions. Subjects (n=334) from 124 families in rural areas of Northern China were recruited. After a 3-day baseline observation, participants sequentially maintained a 7-day low-sodium diet (NaCl, 3 g per day; or sodium, 51.3 mmol per day), followed by a 7-day high-sodium diet (NaCl, 18 g per day; or sodium, 307.8 mmol per day) and a 7-day high-sodium plus potassium supplementation intervention (KCl, 4.5 g per day; or potassium, 60 mmol per day). A total of seven single nucleotide polymorphisms (SNPs) in the adiponectin gene were selected as the study sites. After adjustment for multiple testing, the adiponectin SNP rs16861205 was significantly associated with the diastolic BP (DBP) response to low-salt intervention, and the DBP and mean arterial pressure (MAP) responses to high-salt intervention (P=0.028, 0.023 and 0.027, respectively). SNP rs822394 was associated with the DBP and MAP responses to low-salt intervention and the DBP response to high-salt intervention (P=0.023, 0.030 and 0.033 respectively). Meanwhile, significant association also existed between SNP rs16861194 and the systolic BP response to potassium supplementation intervention (P=0.026). In addition, SNP rs822394 was significantly associated with basal DBP after adjustment for multiple testing (P=0.033). Our study indicated that the genetic polymorphisms in the adiponectin gene are significantly associated with BP responses to dietary sodium and potassium intake.

Relationship between the A(8002)G intronic polymorphism of pre-pro-endothelin-1 gene and the endothelin-1 concentration among Tunisian coronary patients

Background

Acute coronary syndromes (ACS) are complex and polygenic diseases which are a real problem of public health. These syndromes require multidisciplinary studies to understand the pathogenesis mechanisms. Our study aims to evaluate the endothelin-1 (ET-1) serum concentration in Tunisian coronary compared to controls healthy, as well as the study of the impact of an intronic polymorphism A (8002) G of pre-pro-endothelin-1 Gene (inactive precursor of ET-1) on the change in serum endothelin-1 and in the susceptibility to Acute coronary syndrome (SCA).

Methods

Our samples were subdivided into coronary patients (157) and healthy subjects (142). The quantification of the ET-1 concentration was performed by high performance liquid chromatography, the identification of the different genotypes of the polymorphism A(8002)G was made by PCR-RFLP. The association between the ET-1 concentration and identified genotypes was realized by adapted software for descriptive statistics, Statistical Package for the Sociological Sciences (SPSS v 21.0).

Results

Our study showed that the concentration of ET-1 was significantly higher in patients compared to controls and that the mutated allele prevails in patients F (G) = 0.78 and there is a minority in controls F (G) = 0.3. Secondly the homozygous genotype GG is associated with higher concentrations of ET-1 in patients and controls, heterozygous genotype AG is associated with intermediaries’ values and AA genotype is related to lower values.

Conclusion

Although the polymorphism studied is an intronic polymorphism, it is involved in the change in serum concentration of ET-1 and is a candidate gene in susceptibility to SCA. Cardiovascular diseases are “polygenic” pathology and do not obey of the law for transmission of Mendel.

Potassium and Its Discontents: New Insight, New Treatments

Hyperkalemia is common in patients with impaired kidney function or who take drugs that inhibit the renin-angiotensin-aldosterone axis. During the past decade, substantial advances in understanding how the body controls potassium excretion have been made, which may lead to improved standard of care for these patients. Renal potassium disposition is primarily handled by a short segment of the nephron, comprising part of the distal convoluted tubule and the connecting tubule, and regulation results from the interplay between aldosterone and plasma potassium. When dietary potassium intake and plasma potassium are low, the electroneutral sodium chloride cotransporter is activated, leading to salt retention. This effect limits sodium delivery to potassium secretory segments, limiting potassium losses. In contrast, when dietary potassium intake is high, aldosterone is stimulated. Simultaneously, potassium inhibits the sodium chloride cotransporter. Because more sodium is then delivered to potassium secretory segments, primed by aldosterone, kaliuresis results. When these processes are disrupted, hyperkalemia results. Recently, new agents capable of removing potassium from the body and treating hyperkalemia have been tested in clinical trials. This development suggests that more effective and safer approaches to the prevention and treatment of hyperkalemia may be on the horizon.

G-231A and G+70C Polymorphisms of Endothelin Receptor Type-A Gene could Affect the Psoriasis Area and Severity Index Score and Endothelin 1 Levels

Background:

The etiopathogenesis of psoriasis has not been clearly elucidated although the role of chronic inflammation, imbalance between pro- and anti-inflammatory cytokines, and many immunological events have been established. Endothelin 1 (EDN1) and endothelin receptor type-A (EDNRA) are implicated in the inflammatory process. The relationships between EDN1 and EDNRA polymorphisms with several diseases have been found.

Aims and Objectives:

This study examined the possible association of EDN1 (G5665T and T-1370G) and EDNRA (G-231A and G + 70C) single nucleotide polymorphisms (SNPs) with the occurence of psoriasis, and evaluated the relationship between genotypes and clinical/laboratory manifestation of psoriasis.

Materials and Methods:

We analyzed genotype and allele distributions of the above-mentioned polymorphisms in 151 patients with psoriasis and 152 healthy controls by real-time PCR combined with melting curve analysis.

Results:

We did not find significant differences in the genotype and allele distributions of EDN1 T-1370G, EDNRA G-231A, and EDNRA G+70C polymorphisms between patients with psoriasis and healthy controls. Psoriasis area and severity index (PASI) score of EDNRA –231 polymorphic A allele carrying subjects (AA and AA + AG) was higher than that of wild homozygotes (P = 0.044 and P = 0.027, respectively). In addition, EDN1 levels in EDNRA+70 polymorphic C allele carriers (CC + CG) were elevated when compared with GG genotype; however, the difference was at borderline significance (P = 0.05).

Conclusion:

Although there were no associations between studied polymorphisms and psoriasis susceptibility, the PASI score and EDN1 levels seem to be affected by EDNRA G-231A and G + 70C polymorphisms.

Dietary potassium: a key mediator of the cardiovascular response to dietary sodium chloride

Potassium and sodium share a yin/yang relationship in the regulation of blood pressure (BP). BP is directly associated with the total body sodium and negatively correlated with the total body potassium. Epidemiologic, experimental, and clinical studies have shown that potassium is a significant regulator of BP and further improves cardiovascular outcomes. Hypertensive cardiovascular damage, stroke, and stroke-related death are accelerated by salt intake but might be curbed by increasing dietary potassium intake. The antihypertensive effect of potassium supplementation appears to occur through several mechanisms that include regulation of vascular sensitivity to catecholamines, promotion of natriuresis, limiting plasma renin activity, and improving endothelial function. In the absence of chronic kidney disease, the combined evidence suggests that a diet rich in potassium content serves a vasculoprotective function, particularly in the setting of salt-sensitive hypertension and prehypertension.

Genome-wide linkage and positional candidate gene study of blood pressure response to dietary potassium intervention: the genetic epidemiology network of salt sensitivity study

BACKGROUND

Genetic determinants of blood pressure (BP) response to potassium, or potassium sensitivity, are largely unknown. We conducted a genome-wide linkage scan and positional candidate gene analysis to identify genetic determinants of potassium sensitivity.

METHODS AND RESULTS

A total of 1906 Han Chinese participants took part in a 7-day high-sodium diet followed by a 7-day high-sodium plus potassium dietary intervention. BP measurements were obtained at baseline and after each intervention using a random-zero sphygmomanometer. Significant linkage signals (logarithm of odds [LOD] score, >3) for BP responses to potassium were detected at chromosomal regions 3q24-q26.1, 3q28, and 11q22.3-q24.3. Maximum multipoint LOD scores of 3.09 at 3q25.2 and 3.41 at 11q23.3 were observed for absolute diastolic BP (DBP) and mean arterial pressure (MAP) responses, respectively. Linkage peaks of 3.56 at 3q25.1 and 3.01 at 11q23.3 for percent DBP response and 3.22 at 3q25.2, 3.01 at 3q28, and 4.48 at 11q23.3 for percent MAP response also were identified. Angiotensin II receptor, type 1 (AGTR1), single-nucleotide polymorphism rs16860760 in the 3q24-q26.1 region was significantly associated with absolute and percent systolic BP responses to potassium (P=0.0008 and P=0.0006, respectively). Absolute (95% CI) systolic BP responses for genotypes C/C, C/T, and T/T were -3.71 (-4.02 to -3.40), -2.62 (-3.38 to -1.85), and 1.03 (-3.73 to 5.79) mm Hg, respectively, and percent responses (95% CI) were -3.07 (-3.33 to -2.80), -2.07 (-2.74 to -1.41), and 0.90 (-3.20 to 4.99), respectively. Similar trends were observed for DBP and MAP responses.

CONCLUSIONS

Genetic regions on chromosomes 3 and 11 may harbor important susceptibility loci for potassium sensitivity. Furthermore, the AGTR1 gene was a significant predictor of BP responses to potassium intake.