Interaction between plasma potassium and epinephrine in coronary thrombosis in dogs

Estimated Intake of Potassium, Phosphorus and Zinc with the Daily Diet Negatively Correlates with ADP-Dependent Whole Blood Platelet Aggregation in Older Subjects

The aggregation of blood platelets is the pivotal step that leads to thrombosis. The risk of thrombotic events increases with age. Available data suggest that minerals taken with diet can affect the course of thrombosis. However, little is known about the relationship between platelet aggregability and mineral intake with diet among elderly people. Thus, we evaluated the associations between the reactivities of platelets to arachidonic acid, collagen or ADP and the estimated quantities of minerals consumed as a part of the daily diet in 246 subjects aged 60-65 years (124 men and 122 women). The found simple (not-adjusted) Spearman's rank negative correlations are as follows: 1. arachidonate-dependent aggregation and the amounts of potassium, zinc, magnesium, phosphorus, iron, copper and manganese; 2. collagen-dependent aggregation and the amounts of potassium, phosphorus, iron and zinc; and 3. ADP-dependent aggregation and the amounts of potassium, phosphorus and zinc. The negative associations between ADP-dependent platelet reactivity and the amount of potassium, phosphorus and zinc and between collagen-dependent aggregability and the amount of phosphorus were also noted after adjusting for a bunch of cardiovascular risk factors. Overall, in older subjects, the intake of minerals with diet is negatively related to blood platelet reactivity, especially in response to ADP. Diet fortification with some minerals may possibly reduce the thrombotic risk among elderly patients.

Potassium status and the risk of type 2 diabetes, cardiovascular diseases, and mortality: a meta-analysis of prospective observational studies

Epidemiological evidence on the association between potassium and cardiometabolic outcomes remains controversial. This study aimed to examine associations of dietary intake and blood and urinary levels of potassium with risk of type 2 diabetes, cardiovascular disease (CVD), and mortality. Relevant prospective studies were retrieved through a comprehensive search of four electronic databases up to July 1, 2023. Random-effects models were used to pool the study-specific relative risks (RRs) and 95% confidence intervals (CIs). Fifty-six studies were included in this meta-analysis. A higher intake of potassium was significantly associated with a 16% lower risk of CVD (RR: 0.84, 95% CI: 0.78-0.90). Similar inverse associations were also observed between potassium intake and mortality. Each 1.0 g/d increment in potassium intake was associated with a decreased risk of CVD (RR: 0.85, 95% CI: 0.80-0.91) and all-cause mortality (RR: 0.93, 95% CI: 0.88-0.99). For blood and urinary potassium levels, higher level of blood potassium increased the risk of all-cause mortality by 23% (RR: 1.23, 95% CI: 1.11-1.36). The association of blood potassium levels with mortality was nonlinear (Pnon-linearit<0.001). However, urinary potassium levels were inversely associated with the risk of all-cause mortality (RR: 0.84, 95% CI: 0.76-0.93). Our findings support the benefits of moderate potassium consumption for primary prevention of chronic diseases and premature death.

Cardiovascular risk factors are associated with augmented thrombogenicity in healthy individuals: analysis using the Total Thrombus-formation Analysis System

BACKGROUND

Rupture of an atherosclerotic plaque and subsequent exposure of the subendothelial prothrombotic matrix to blood cause arterial thrombosis. Circulating platelets play an indispensable role in the growth of arterial thrombi partially owing to their unique ability to adhere to the subendothelial matrix and to aggregate to each other under flow conditions. Recently, the Total Thrombus-formation Analysis System (T-TAS) was developed for ex vivo analysis of the thrombogenic potential of whole blood samples under flow conditions. Despite the potential clinical utility of the T-TAS in assessing the risk for thrombosis and bleeding, reference intervals for T-TAS analysis in healthy individuals have not been determined.

METHODS

In total, 122 whole blood samples were collected from healthy volunteers ranging in age from 25 to 45 years. T-TAS analysis and hematological, physiological, and lifestyle assessments were conducted in these subjects. Whole blood samples anticoagulated with hirudin were perfused into a collagen-coated microchip (PL chip). The time to 10 kPa and the area under the flow pressure curve up to 10 min (AUC₁₀) were analyzed as representative variables for thrombogenic potential. Reference intervals, which were defined as 2.5-97.5 percentiles, were determined. Additionally, univariate and multivariate analyses were performed to identify factors associated with the AUC₁₀ in the T-TAS.

RESULTS

The time to 10 kPa and the AUC₁₀ widely varied, even in healthy volunteers. The reference intervals were 1.50-4.02 min and 223.4-456.8, respectively, at a shear rate of 1500 s^- 1. Univariate and multivariate analyses showed that platelet counts were most significantly associated with the AUC₁₀ of the T-TAS. The presence of one or more cardiovascular risk factors of a high body mass index, a high pulse pressure, high fasting serum glucose levels, high low-density lipoprotein-cholesterol levels, a history of smoking, and no habitual exercise, had the second largest effect on the AUC₁₀ of the T-TAS.

CONCLUSIONS

Healthy volunteers who had any cardiovascular risk factors showed augmented thrombogenicity, even in artificial uniform capillaries, compared with those without any risk factors in the T-TAS.

Randomized Trial on the Effects of Dietary Potassium on Blood Pressure and Serum Potassium Levels in Adults with Chronic Kidney Disease

In the general population, an increased potassium (K) intake lowers blood pressure (BP). The effects of K have not been well-studied in individuals with chronic kidney disease (CKD). This randomized feeding trial with a 2-period crossover design compared the effects of diets containing 100 and 40 mmol K/day on BP in 29 adults with stage 3 CKD and treated or untreated systolic BP (SBP) 120–159 mmHg and diastolic BP (DBP) <100 mmHg. The primary outcome was 24 h ambulatory systolic BP. The higher-versus lower-K diet had no significant effect on 24 h SBP (−2.12 mm Hg; p = 0.16) and DBP (−0.70 mm Hg; p = 0.44). Corresponding differences in clinic BP were −4.21 mm Hg for SBP (p = 0.054) and −0.08 mm Hg for DBP (p = 0.94). On the higher-K diet, mean serum K increased by 0.21 mmol/L (p = 0.003) compared to the lower-K diet; two participants had confirmed hyperkalemia (serum K ≥ 5.5 mmol/L). In conclusion, a higher dietary intake of K did not lower 24 h SBP, while clinic SBP reduction was of borderline statistical significance. Additional trials are warranted to understand the health effects of increased K intake in individuals with CKD.

Postprandial effect to decrease soluble epoxide hydrolase activity: roles of insulin and gut microbiota

Epoxides of free fatty acids (FFAs), especially epoxyeicosatrienoic acids (EETs), are lipid mediators with beneficial effects in metabolic and cardiovascular (CV) health. FFA epoxides are quickly metabolized to biologically less active diols by soluble epoxide hydrolase (sEH). Inhibition of sEH, which increases EET levels, improves glucose homeostasis and CV health and is proposed as an effective strategy for the treatment of diabetes and CV diseases. Here, we show evidence that sEH activity is profoundly reduced in postprandial states in rats; plasma levels of 17 sEH products (i.e., FFA diols), detected by targeted oxylipin analysis, all decreased after a meal. In addition, the ratios of sEH product to substrate (sEH P/S ratios), which may reflect sEH activity, decreased ~70% on average 2.5 h after a meal in rats (P<.01). To examine whether this effect was mediated by insulin action, a hyperinsulinemic-euglycemic clamp was performed for 2.5 h, and sEH P/S ratios were assessed before and after the clamp. The clamp resulted in small increases rather than decreases in sEH P/S ratios (P<.05), indicating that insulin cannot account for the postprandial decrease in sEH P/S ratios. Interestingly, in rats treated with antibiotics to deplete gut bacteria, the postprandial effect to decrease sEH P/S ratios was completely abolished, suggesting that a gut bacteria-derived factor(s) may be responsible for the effect. Further studies are warranted to identify such a factor(s) and elucidate the mechanism by which sEH activity (or sEH P/S ratio) is reduced in postprandial states.

Plasma potassium, diuretic use and risk of developing chronic kidney disease in a predominantly White population

Objective

Both hypokalemia and hyperkalemia are associated with disease progression in patients with chronic kidney disease (CKD). It is unclear whether similar associations are present in the general population. Our aim was to examine the association of plasma potassium with risk of developing CKD and the role of diuretics in this association in a population-based cohort.

Research design and methods

We studied 5,130 subjects free of CKD at baseline of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study, a prospective, population-based cohort of Dutch men and women aged 28–75 years. Hypokalemia was defined as plasma potassium <3.5 mmol/L, and hyperkalemia as plasma potassium ≥5.0 mmol/L. Risk of CKD was defined as de novo development of eGFR <60 ml/min/1.73m² and/or albuminuria >30 mg/24h.

Results

Mean baseline plasma potassium was 4.4±0.3 mmol/L. The prevalences of hypokalemia and hyperkalemia were 0.5% and 3.8%, respectively; 3.0% of the subjects used diuretics. During a median follow-up of 10.3 years (interquartile range: 6.3–11.4 years), 753 subjects developed CKD. The potassium-CKD association was modified by diuretic use (P_interaction = 0.02). Both hypokalemia without (HR, 7.74, 95% CI, 3.43–17.48) or with diuretic use (HR, 4.32, 95% CI, 1.77–10.51) were associated with an increased CKD risk as compared to plasma potassium 4.0–4.4 mmol/L without diuretic use. Plasma potassium concentrations ≥3.5 mmol/L were associated with an increased CKD risk among subjects using diuretics (P_trend = 0.01) but not among subjects not using diuretics (P_trend = 0.74).

Conclusion

In this population-based cohort, hypokalemia was associated with an increased CKD risk, regardless of diuretic use. In the absence of hypokalemia, plasma potassium was not associated with an increased CKD risk, except among subjects using diuretics.

Hypokalemia in acute medical patients: risk factors and prognosis

OBJECTIVE

Hypokalemia is one of the most common electrolyte disorders in hospitalized patients. It is associated with a high mortality rate among patients with cardiovascular disease. Whether hypokalemia confers a similar risk in an unselected hospitalized population is not well established.

METHODS

We conducted a prospective cohort study involving all first-time admissions (n = 11,988) to the Acute Medical Department at Odense University Hospital linking potassium level at admission with registry data on patient characteristics, laboratory data, redeemed prescriptions, and time of death for the period from August 2009 to August 2011. We estimated hazard ratios for all-cause mortality within 0 to 7 days and 8 to 30 days after admission, comparing patients with hypokalemia at admission (plasma [K(+)] level <3.4 mmol/L) with patients with eukalemia at admission ([K(+)] level of 3.4-3.8 mmol/L).

RESULTS

Hypokalemia occurred in 16.8% of first-time admissions (n = 2011). It was associated with an adjusted hazard ratio [HR] of 1.34 (95% confidence interval [CI], 0.98-1.85) for 7-day mortality and 1.56 (95% CI, 1.18-3.06) for 8- to 30-day mortality. Among patients with more severe hypokalemia (plasma [K(+)] <2.9 mmol/L), the adjusted HR was 2.17 (95% CI, 1.34-3.49) for 7-day mortality and 1.90 (95% CI, 1.18-3.06) for 8- to 30-day mortality. Prognostic factors for both 7-day and 8- to 30-day mortality among hypokalemic patients were increasing age and Charlson Comorbidity Index, whereas there was no prognostic effect of current diuretic or beta-agonist use.

CONCLUSIONS

In a mixed population of hospitalized medical patients, hypokalemia is common, and plasma [K(+)] <2.9 mmol/L is associated with increased 7-day and 8- to 30-day mortality.

Low serum potassium concentration is a predictor of chronic kidney disease

AIMS

The aim of this study was to examine whether low serum potassium concentration could be a predictor of chronic kidney disease (CKD) in a community-based cohort.

MATERIALS AND METHODS

We enrolled 1001 subjects, median period of 5.7 years, and evaluated the risk factors for CKD, defined as estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m(2), and assessed whether low serum potassium concentration could predict CKD.

RESULTS

Compared with the subjects without development of CKD, age, body mass index, fasting plasma glucose, uric acid (UA), creatinine and serum sodium concentration were higher, and serum potassium concentration was lower in subjects with development of CKD. Univariate Cox regression analyses demonstrated that age, body mass index, fasting plasma glucose, UA, creatinine, serum sodium concentration and serum potassium concentration were associated with progression of CKD. Multiple Cox regression analysis revealed that age, gender, creatinine and serum potassium concentration were independent predictors of CKD after adjustment for covariates. When serum potassium concentration was below 4.0 mmol/l at baseline, hazard ratio (95% confidence interval) of developing CKD was 2.65 (2.04-3.44; p < 0.0001).

CONCLUSIONS

Serum potassium concentration could be a clinically relevant risk factor for the progression of CKD, defined as eGFR < 60 ml/min/1.73 m(2) , in healthy subjects.

Study of the mechanisms of aldosterone prothrombotic effect in rats

INTRODUCTION

We investigated the role of primary haemostasis, fibrinolysis, nitric oxide (NO) and oxidative stress as well as mineralocorticoid receptors (MR) in acute aldosterone prothrombotic action.

MATERIALS AND METHODS

Venous thrombosis was induced by stasis in Wistar rats. Aldosterone (ALDO; 10, 30, 100 µg/kg/h) was infused for 1 h. Eplerenone (EPL; 100 mg/kg, p.o.), a selective MR antagonist, was administered before ALDO infusion. Bleeding time (BT) and platelet adhesion to collagen were evaluated. The expression of nitric oxide synthase (NOS), NADPH oxidase, superoxide dismutase (SOD) and plasminogen activator inhibitor (PAI-1) was measured. NO, malonyl dialdehyde (MDA) and hydrogen peroxide (H(2)O(2)) plasma levels were assayed.

RESULTS

Significant enhancement of venous thrombosis was observed after ALDO infusion. ALDO shortened BT and increased platelet adhesion. Marked increases were observed in PAI-1, NADPH oxidase and SOD mRNA levels. MDA and H(2)O(2) levels were augmented in ALDO-treated groups, and NOS expression and NO level were decreased. EPL reduced ALDO effects on thrombus formation, primary haemostasis, PAI-1 expression and MDA level.

CONCLUSION

Short-term ALDO infusion enhances experimental venous thrombosis in the mechanism involving primary haemostasis, fibrinolysis, NO and oxidative stress-dependent pathways. The MR antagonist only partially diminished the ALDO effects, suggesting the involvement of additional mechanisms.

A propensity-matched study of low serum potassium and mortality in older adults with chronic heart failure

OBJECTIVE

Most HF patients are older adults, yet the associations of low serum potassium and outcomes in these patients are unknown. We studied the effect of low serum potassium in a propensity-matched population of elderly HF patients.

METHODS

Of the 7788 patients in the Digitalis Investigation Group trial, 4036 were >or=65 years. Of these, 3598 had data on baseline serum potassium and 324 with potassium >or=5 mEq/L were excluded. Remaining patients were categorized into low (<4 mEq/L; n=590) and normal (4-4.9 mEq/L; n=2684) potassium groups. Propensity scores for low-potassium, calculated for each patient, were used to match 561 low-potassium and 1670 normal-potassium patients. Association of low potassium and outcomes were assessed using matched Cox regression analyses.

RESULTS

Patients had a mean (+/-SD) age of 72 (+/-6) years, 29% were women and 12% were non-whites. Of the 561 low-potassium patients, 500 had low-normal (3.5-3.9 mEq/L) potassium. All-cause mortality occurred in 37% (rate, 1338/10,000 person-years) normal-potassium and 43% (rate, 1594/10,000 person-years) low-potassium patients (hazard ratio {HR} for low-potassium, 1.22; 95% confidence interval {CI}, 1.04-1.44; p=0.014). Low-normal (3.5-3.9 mEq/L) potassium levels had a similar association with mortality (HR, 1.19, 95% CI, 1.00-1.41, p=0.049). Low (HR, 1.10; 95% CI, 0.96-1.25; p=0.175) or low-normal (HR=1.09, 95% CI=0.95-1.25, p=0.229) serum potassium levels were not associated with all-cause hospitalization.

CONCLUSIONS

In a propensity-matched population of elderly ambulatory chronic HF patients, well-balanced in all measured baseline covariates, low and low-normal serum potassium were associated with increased mortality but had no association with hospitalization.

Metabolic side effects and cardiovascular events of diuretics: should a diuretic remain the first choice therapy in hypertension treatment? The case of yes

Essential hypertension is a major cause of cardiovascular morbidity and mortality in the Western world. Numerous clinical trials have demonstrated that the treatment of hypertension results in a substantial reduction of hypertension-related morbidity and mortality. The efficacy and safety of diuretics has been shown in many clinical trials. Like most other antihypertensive agents, the side effects of diuretics are mostly benign and mild. The metabolic side effects of diuretics, however, have been a bone of contention for a long time. In this paper, we describe the most important and frequent metabolic side effects of diuretics, and emphasize particularly the non-life-threatening effect of diuretics on ventricular arrhythmias due to their hypokalemic effect, the detection of the new onset diabetes (perhaps caused by the administration of diuretics itself), and their significant beneficial effect on cardiovascular and cerebrovascular morbidity and mortality. At the end of the article, we highlighted the differences regarding the prescription of diuretics between the recently published American and European Guidelines of hypertension.

Renal and extrarenal regulation of potassium

The ISN Forefronts in Nephrology Symposium took place 8-11 September 2005 in Kartause Ittingen, Switzerland. It was dedicated to the memory of Robert W. Berliner, who died at age 86 on 5 February 2002. Dr Berliner contributed in a major way to our understanding of potassium transport in the kidney. Starting in the late 1940s, without knowledge of how potassium was transported across specific nephron segments and depending only on renal clearance methods, he and his able associates provided a still-valid blueprint of the basic transport properties of potassium handling by the kidney. They firmly established that potassium was simultaneously reabsorbed and secreted along the nephron; that variations in secretion in the distal nephron segments play a major role in regulating potassium excretion; and that such secretion is modulated by sodium, acid-base factors, hormones, and diuretics. These conclusions were presented in a memorable Harvey Lecture some forty years ago, and they have remained valid ever since. The concepts have also provided the foundation and stimulation for later work on single nephrons, tubule cells, and transport proteins involved in potassium transport.

Dietary Flavanols and Platelet Reactivity

Epidemiology studies suggest that the consumption of diets rich in flavonoids is associated with reduced risk of cardiovascular disease. Plant-derived foods and beverages, such as red wine, tea, grape and grape juice, cocoa and chocolate, can be rich in 1 particular class of flavonoid, the flavan-3-ols. There is now an increasing body of research that suggests that consuming flavanol-rich foods can positively affect hemostasis, through mechanisms that either directly affect platelet function or increase certain endothelium-derived factors that maintain platelet acquiescence or increase fibrinolysis. In this paper, we will review a series of in vivo studies on the effects of flavanol-rich cocoa and chocolate on platelet activation and platelet-dependent hemostasis. In addition, we will briefly review the body of literature with regard to other flavanol-rich foods and beverages, and possible mechanisms of action.

The cardiovascular implications of hypokalemia

The role of potassium in the progression of cardiovascular disease is complex and controversial. Animal and human data suggest that increases in dietary potassium, decreases in urinary potassium loss, or increases in serum potassium levels through other mechanisms have benefits in several disease states. These include the treatment of hypertension, stroke prevention, arrhythmia prevention, and treatment of congestive heart failure. Recently, the discovery that aldosterone antagonists not only decrease sodium reabsorption and decrease potassium secretion in the nephron, but also decrease pathological injury of such nonepithelial tissues as the myocardium and endothelium, has generated great controversy regarding the actual mechanisms of benefit of these agents. We review the available data and draw conclusions about the relative benefits of modulating potassium balance versus nonrenal effects of aldosterone blockade in patients with cardiovascular disease.

Protective effects of dietary potassium chloride on hemodynamics of Dahl salt-sensitive rats in response to chronic administration of sodium chloride

BACKGROUND

Dietary potassium supplementation decreases blood pressure and prevents strokes in humans, and prevents strokes and renal damage in Dahl salt-sensitive (DSS) rats.

OBJECTIVE

To study the effects of various concentrations of dietary potassium chloride (KCl) on the hemodynamics of Dahl salt-resistant (DSR) and DSS rats receiving a 1% sodium chloride (NaCl) diet for 8 months, to determine whether there is an optimal dietary concentration of KCl that minimizes increases in blood pressure and causes least impairment of blood flow in the brain and kidneys.

METHODS AND RESULTS

We found a biphasic effect on hemodynamic parameters as a function of dietary KCl in DSS rats of the Rapp strain fed 1% NaCl with increasing dietary KCl (0.7, 2.6, 4 and 8%). After 8 months receiving a diet containing 1% NaCl and 0.7% KCl, DSS rats had mean arterial pressures (MAP), plasma volumes, cardiac outputs and renal and cerebral vascular resistances that were significantly increased compared with those of DSR rats receiving the same diet. With a 2.6% KCl diet, all these parameters were significantly reduced compared with those in DSS rats fed the 0.7% KCl diet and were similar to those in DSR rats fed 2.6% KCl. Total peripheral resistance in DSR and DSS rats was similar on all diets. When KCl was increased to 4 and 8%, MAP, plasma volume, cardiac output and renal vascular resistance progressively increased in DSR and DSS rats, without changing total peripheral resistance. These changes paralleled increases in plasma aldosterone, which resulted from adrenocortical stimulation by the increasing dietary KCl; however, cerebral vascular resistance of DSR and DSS rats decreased significantly with a 4% KCl diet, despite increased aldosterone and sodium retention. Only DSS rats fed a 2.6% KCl diet had hemodynamics similar to those of DSR control rats fed the same diet, and hyperaldosteronism, sodium retention and increased plasma volume did not occur.

CONCLUSION

'Optimal' dietary KCl (2.6%) prevents hypertension and preserves cerebral and renal hemodynamics in DSS rats fed a diet containing 1% NaCl for 8 months, which causes hypertension when dietary KCl is limited or excessive.

Dietary minerals and modification of cardiovascular risk factors

High serum cholesterol, hypertension and obesity are major risk factors for cardiovascular diseases, and together with insulin resistance form a deadly disorder referred to as the metabolic syndrome. All the aspects of this syndrome are strongly related to dietary and lifestyle factors; therefore, it would be reasonable to look for dietary approaches to their modification. Mineral nutrients, such as calcium, potassium and magnesium, lower blood pressure, and especially calcium has beneficial effects also on serum lipids. Recent evidence suggests that increased intake of calcium may help in weight control as well. This review summarizes previous literature on the effects and use of dietary minerals on serum lipids, blood pressure and obesity, with specific focus on the effects of calcium. Calcium and magnesium as divalent cations can form insoluble soaps with fatty acids in the intestine and thus prevent the absorption of part of the dietary fat. Decreased absorption of saturated fat leads to reduction in serum cholesterol level via decreased production of VLDL and increased intake of LDL in the liver. Dietary calcium may also bind bile acids, which increases the conversion of cholesterol to bile acids in the liver. Furthermore, calcium appears to enhance the cholesterol-lowering effect of plant sterols. Thus, dietary combination of the mineral nutrients and plant sterols provides a promising novel approach to the modification of cardiovascular risk factors.

High potassium intake inhibits neointima formation in the rat carotid artery balloon injury model

Recently, we reported that elevated extracellular potassium concentration in vitro inhibited proliferation and migration of vascular smooth muscle cells, formation of free radical compounds by macrophages, and reduced platelet sensitivity to agonists. In the present study we analyzed the effects of long-term, in vivo elevation of extracellular potassium concentration resulting from changes in dietary potassium intake on the vascular response to injury. The rat carotid artery balloon injury model was employed in 70 adult Sprague Dawley rats assigned to three groups. Beginning 14 days before surgical placement of the carotid lesion and continuing until death, the animals were fed diets containing either low (0.1% potassium, n = 25), normal (1.5% potassium, n = 19), or high potassium (4.0% potassium, n = 26). Fourteen days postsurgery the animals were killed and the arteries were analyzed to determine quantitatively the ratio of neointimal to medial area. Dietary potassium had a significant effect on arterial plasma potassium concentration (one-way analysis of variance, P < .01). Group mean and standard errors were 4.26+/-0.12 mmol/L for the low-potassium group, 5.22+/-0.19 mmol/L for normal, and 5.80+/-0.23 mmol/L for the high-intake group. Increases in dietary potassium attenuated neointima formation significantly (P < .05, one-way analysis of variance), with the mean ratio of neointimal area to medial area being 0.447+/-0.106 for the low-intake animals, 0.384+/-.116 for normal, and 0.240+/-.046 for the high-intake group. These results are consistent with a hypothesis that a high level of potassium intake is effective in inhibiting neointima formation in vivo.