Antonio Felipe Sanjuliani

Effects of magnesium on blood pressure and intracellular ion levels of Brazilian hypertensive patients

Fifteen patients with uncomplicated mild to moderate primary hypertension (7 males, 8 females, age range 36-65 years) were submitted to a double blind randomized crossover study, receiving MgO 3 times a day at a daily dose of 1.0 g (600 mg/day of magnesium) and placebo for a period of 6 weeks. This was to test the effects of oral magnesium supplementation on blood pressure and sodium, potassium, calcium and magnesium intraerythrocyte concentrations. Concomitantly, plasma renin activity and serum aldosterone was also measured. Oral magnesium reduced significantly the systolic (delta = -7.6 mmHg, P < 0.05); diastolic (delta = -3.8 mmHg, P < 0.01) and mean blood pressure (delta = -5.9 mmHg, P < 0.01). After magnesium supplementation intraerythrocyte sodium concentration was reduced (delta = -0.55 mEq/l per cell, P < 0.01) and intraerythrocyte magnesium concentration was increased (delta = 1.20 mg/dl per cell, P < 0.01). The diminution of the blood pressure correlated positively with the reduction in intraerythrocyte sodium (r = 0.66, P < 0.01) after magnesium. However, our results have shown that the blood pressure response to oral magnesium was not homogeneous. Forty percent of our patients had their blood pressure effectively controlled (more than 10 mmHg reduction in mean blood pressure), being the hypotensive effect more evident in patients with recent hypertension and in those where the reduction in intraerythrocyte sodium was significantly greater than in the non-responder individuals. Intraerythrocyte potassium and calcium, serum aldosterone, plasma renin activity and urinary sodium excretion were maintained unchanged after magnesium supplementation. These data showed that oral magnesium supplementation may reduce the blood pressure, which can be partially explained by the decrease in intracellular sodium and augment in intracellular magnesium.

Dietary calcium intake is associated with adiposity, metabolic profile, inflammatory state and blood pressure, but not with erythrocyte intracellular calcium and endothelial function in healthy pre-menopausal women

Recent studies have suggested that dietary Ca may have beneficial effects on adiposity, insulin resistance, dyslipidaemia and blood pressure (BP). One potential mechanism underlying these benefits involves modifications in intracellular Ca concentration ([Ca2+]i). The present study aimed to evaluate the associations of dietary Ca with adiposity, erythrocyte [Ca2+]i, metabolic profile, BP, inflammatory state and endothelial function in healthy pre-menopausal women. In the present cross-sectional study, seventy-six women aged 18–50 years were submitted to the evaluation of dietary intake, anthropometric parameters, body composition, erythrocyte [Ca2+]i, biochemical variables, endothelial function and BP. A FFQ was used to assess usual dietary intake. Endothelial function was evaluated by serum concentrations of adhesion molecules and by the peripheral arterial tonometry (PAT) method, using Endo-PAT 2000®. Participants were allocated into two groups according to Ca intake: low-Ca group (LCG; n 32; < 600 mg/d) and high-Ca group (HCG; n 44; ≥ 600 mg/d). Women in the LCG compared with those in the HCG exhibited, after adjustments for potential confounders, higher values of BMI, waist circumference, waist:height ratio, percentage of body fat, insulin, homeostasis model assessment of insulin resistance, leptin, diastolic and mean BP; and lower levels of HDL-cholesterol, adiponectin and vascular cell adhesion molecule 1. Endothelial function assessed by PAT and [Ca2+]i was similar in both groups. Subjects in the HCG had lower OR for prevalent overweight, obesity, abdominal obesity, insulin resistance, HDL-cholesterol < 600 mg/l and systolic BP >120 mmHg. The findings of the present study suggest that high Ca intake is inversely associated with some cardiovascular risk factors.

Consumption of High-Polyphenol Dark Chocolate Improves Endothelial Function in Individuals with Stage 1 Hypertension and Excess Body Weight

Background. Hypertension and excess body weight are important risk factors for endothelial dysfunction. Recent evidence suggests that high-polyphenol dark chocolate improves endothelial function and lowers blood pressure. This study aimed to evaluate the association of chocolate 70% cocoa intake with metabolic profile, oxidative stress, inflammation, blood pressure, and endothelial function in stage 1 hypertensives with excess body weight. Methods. Intervention clinical trial includes 22 stage 1 hypertensives without previous antihypertensive treatment, aged 18 to 60 years and presents a body mass index between 25.0 and 34.9 kg/m2. All participants were instructed to consume 50 g of chocolate 70% cocoa/day (2135 mg polyphenols) for 4 weeks. Endothelial function was evaluated by peripheral artery tonometry using Endo-PAT 2000 (Itamar Medical). Results. Twenty participants (10 men) completed the study. Comparison of pre-post intervention revealed that (1) there were no significant changes in anthropometric parameters, percentage body fat, glucose metabolism, lipid profile, biomarkers of inflammation, adhesion molecules, oxidized LDL, and blood pressure; (2) the assessment of endothelial function through the reactive hyperemia index showed a significant increase: 1.94 ± 0.18 to 2.22 ± 0.08, P = 0.01. Conclusion.In individuals with stage 1 hypertension and excess body weight, high-polyphenol dark chocolate improves endothelial function.

Antihypertensive Treatment Improves Microvascular Rarefaction and Reactivity in Low-Risk Hypertensive Individuals

To test whether long‐term antihypertensive treatment with metoprolol succinate (a β1‐adrenoceptor blocker) or olmesartan medoxomil (an angiotensin II AT1‐receptor blocker) reverses microvascular dysfunction in hypertensive patients.

Effect of a high-calcium energy-reduced diet on abdominal obesity and cardiometabolic risk factors in obese Brazilian subjects

Background:  Clinical trials designed to examine the effects of calcium supplementation on abdominal obesity have had ambiguous results.

Selective imidazoline agonist moxonidine in obese hypertensive patients

Obesity is the major risk factor for the development of hypertension. This association accentuates the risk of cardiovascular disease, as it is frequently accompanied by the components of the metabolic syndrome. This randomised open parallel study evaluated the chronic effects of moxonidine – a selective imidazoline receptor agonist – on blood pressure, plasma catecholamines, leptin, insulin and components of the metabolic syndrome in obese hypertensives. Amlodipine was used as the control drug. Our results showed that moxonidine and amlodipine significantly reduced blood pressure when measured using the oscillometric method and 24‐hour blood pressure monitoring. Moxonidine therapy decreased systolic blood pressure from 160.4 ± 2.4 to 142.1 ± 3.3 mmHg (p < 0.005) and diastolic blood pressure from 102.4 ± 1.3 to 89.7 ± 1.6 mmHg (p < 0.005) after 24 weeks of treatment. Moxonidine administration reduced the supine arterial plasma levels of adrenaline from 63.2 ± 6.6 to 49.0 ± 6.7 pg/ml (p < 0.005), the supine arterial plasma levels of noradrenaline from 187.9 ± 10.7 to 149.7 ± 13.2 pg/ml (p < 0.01) and the orthostatic venous plasma levels of noradrenaline from 258.6 ± 25.0 to 190.3 ± 16.4 pg/ml (p = 0.03). Those variables were not changed by amlodipine. The plasma levels of leptin and insulin 120 min after a glucose load decreased after moxonidine administration from 27.2 ± 3.5 to 22.6 ± 2.9 pg/ml (p < 0.05) and from 139.7 ± 31.2 to 76.0 ± 15.2 U/ml (p < 0.05), respectively. Amlodipine, however, did not modify those variables. This study showed a comparable reduction in blood pressure with both antihypertensive drugs. Moxonidine decreased sympathetic nervous activity, improved insulin resistance and reduced the plasma levels of leptin.

Dietary calcium intake and its relationship with adiposity and metabolic profile in hypertensive patients

OBJECTIVE An inverse relation between dietary calcium and adiposity has been found in several epidemiologic studies. Recent evidence has also suggested that a calcium-rich diet may have beneficial effects on insulin resistance and dyslipidemia. This study aimed to evaluate the association of dietary calcium intake with global adiposity, abdominal obesity, and metabolic profile in hypertensive patients. METHODS In this cross-sectional study, 85 hypertensive patients 25 to 70 y old underwent clinical, dietary, anthropometric, and biochemical evaluations. Participants were stratified into the following two groups according to their usual dietary calcium intake: low calcium group (<800 mg/d) and high calcium group (≥800 mg/d). RESULTS Fifty-seven participants (11 men and 46 women) were included in the final analyses. Subjects in the low calcium group compared with those in the high calcium group exhibited significantly higher levels of body mass index and percentage of body fat after adjustments for variables that could interfere with those adiposity parameters (P = 0.03 and 0.01, respectively). Patients in the high calcium group had a lower odds ratio for prevalent obesity than those in the low calcium group, even after controlling for potential confounders (P = 0.01). No significant differences were found in abdominal adiposity and metabolic profile between the two groups. Using data from all patients, an inverse and significant association was observed between dietary calcium intake and percentage of body fat, and it remained after controlling for confounders (P = 0.03). CONCLUSIONS The findings of the present study suggest that, in hypertensive patients, higher dietary calcium intake could be associated with lower global adiposity.

Effects of weight loss from a high-calcium energy-reduced diet on biomarkers of inflammatory stress, fibrinolysis, and endothelial function in obese subjects

OBJECTIVE Obesity is characterized by chronic subclinical inflammation, which is critical to endothelial dysfunction. Weight loss, induced by lifestyle interventions, is associated with a decline in biomarkers of inflammation and endothelial dysfunction. There is little evidence that high dietary calcium intake may reduce inflammation and improve endothelial function. The purpose of this study was to evaluate the effects of weight loss from a high-calcium energy-reduced diet on biomarkers of inflammation, fibrinolysis, and endothelial function in obese individuals. METHODS In this randomized clinical trial, we analyzed the data from 35 obese adults who lost at least 3% of initial body weight, during a period of 16 wk of energy restriction (-800 Kcal/d). Individuals were randomized into the following dietary regimens: (1) a high calcium diet (HCD; 1200-1300 mg/d) or (2) a low-calcium diet (LCD; <500 mg/d). RESULTS After 16 wk of intervention subjects on HCD compared with those on LCD exhibited greater reduction in waist circumference and waist-to-hip ratio. Participants on HCD presented a significant reduction in all biomarkers of endothelial dysfunction evaluated in the study (intracellular adhesion molecule-1, vascular cell adhesion molecule 1, and E-Selectin), whereas subjects on LCD showed a significant decrease in intracellular adhesion molecule-1 and E-Selectin. Biomarkers of inflammation and fibrinolysis were reduced in both diets, although without reaching statistical significance. The reduction in all markers of inflammation, fibrinolysis, and endothelial dysfunction was similar in both diets. CONCLUSION The findings of this study suggest that increased calcium intake during weight loss has no benefits with respect to biomarkers of inflammation, fibrinolysis, and endothelial function.

Does calcium intake affect cardiovascular risk factors and/or events?

Dietary intervention is an important approach in the prevention of cardiovascular disease. Over the last decade, some studies have suggested that a calcium-rich diet could help to control body weight, with anti-obesity effects. The potential mechanism underlying the impact of calcium on body fat has been investigated, but it is not fully understood. Recent evidence has also suggested that a calcium-rich diet could have beneficial effects on other cardiovascular risk factors, such as insulin resistance, dyslipidemia, hypertension and inflammatory states. In a series of studies, it was observed that a high intake of milk and/or dairy products (the main sources of dietary calcium) is associated with a reduction in the relative risk of cardiovascular disease. However, a few studies suggest that supplemental calcium (mainly calcium carbonate or citrate) may be associated with an increased risk of cardiovascular events. This review will discuss the available evidence regarding the relationship between calcium intake (dietary and supplemental) and different cardiovascular risk factors and/or events.

Spironolactone Versus Clonidine as a Fourth-Drug Therapy for Resistant Hypertension: The ReHOT Randomized Study (Resistant Hypertension Optimal Treatment)

The aim of this study is to compare spironolactone versus clonidine as the fourth drug in patients with resistant hypertension in a multicenter, randomized trial. Medical therapy adherence was checked by pill counting. Patients with resistant hypertension (no office and ambulatory blood pressure [BP] monitoring control, despite treatment with 3 drugs, including a diuretic, for 12 weeks) were randomized to an additional 12-week treatment with spironolactone (12.5–50 mg QD) or clonidine (0.1–0.3 mg BID). The primary end point was BP control during office (<140/90 mm Hg) and 24-h ambulatory (<130/80 mm Hg) BP monitoring. Secondary end points included BP control from each method and absolute BP reduction. From 1597 patients recruited, 11.7% (187 patients) fulfilled the resistant hypertension criteria. Compared with the spironolactone group (n=95), the clonidine group (n=92) presented similar rates of achieving the primary end point (20.5% versus 20.8%, respectively; relative risk, 1.01 [0.55–1.88]; P=1.00). Secondary end point analysis showed similar office BP (33.3% versus 29.3%) and ambulatory BP monitoring (44% versus 46.2%) control for spironolactone and clonidine, respectively. However, spironolactone promoted greater decrease in 24-h systolic and diastolic BP and diastolic daytime ambulatory BP than clonidine. Per-protocol analysis (limited to patients with ≥80% adherence to spironolactone/clonidine treatment) showed similar results regarding the primary end point. In conclusion, clonidine was not superior to spironolactone in true resistant hypertensive patients, but the overall BP control was low (≈21%). Considering easier posology and greater decrease in secondary end points, spironolactone is preferable for the fourth-drug therapy. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01643434.