Acute Effects of Dietary Nitrate on Central Pressure and Endothelial Function in Hypertensive Patients: A Randomized, Placebo-Controlled Crossover Study. / Efeitos Agudos do Nitrato Dietético na Pressão Central e Desempenho Cardíaco em Hipertensos: Estudo Cruzado, Randomizado e Placebo-Controlado.

BACKGROUND: The diet's inorganic nitrate (NO3-) may provide a physiological substrate for reducing nitrate (NO2-) to NO independent of the endothelium. Studies suggest that inorganic NO3- has beneficial effects on cardiovascular health. OBJECTIVE: This study evaluated the acute effects of 500 mL nitrate-rich beetroot juice (BRJ; containing 11.5mmol NO3-) on blood pressure and endothelial function in treated hypertensive patients. METHODS: A randomized, placebo-controlled, crossover study was conducted in treated hypertensive patients (n=37; women=62%) who underwent clinical and nutritional evaluation and assessment of central hemodynamic parameters and microvascular reactivity. The significance level was p<0.05. RESULTS: The mean age was 59±7 years, and mean systolic and diastolic blood pressures were 142±10/83±9mmHg. There was a significant increase in the subendocardial viability ratio (SEVR; 149±25 vs. 165±30%, p<0.001) and reduction in ejection duration (ED; 37±4 vs. 34±4%, p<0.001) in the beetroot phase but no significant SEVR difference in the control phase. The % increase in perfusion (155 vs. 159 %, p=0.042) was significantly increased in the beetroot phase, which was not observed in the control phase. In the beetroot phase, the change in SEVR showed a significant correlation with the change in the area under the curve of post-occlusive reactive hyperemia (AUC-PORH) (r=0.45, p=0.012). The change in ED showed a significant correlation with the post-intervention perfusion peak (r=-0.37, p=0.031) and AUC-PORH (r=-0.36, p=0.046). CONCLUSIONS: The acute ingestion of BRJ by hypertensive patients resulted in an improvement of endothelial function, which was associated with higher subendocardial viability and performance in myocardial contraction.

FUNDAMENTO: O nitrato inorgânico (NO3­) da dieta pode fornecer substrato fisiológico para reduzir o nitrito (NO2­) a óxido nítrico (NO) independente do endotélio. Estudos sugerem que o NO3­ inorgânico tem efeitos benéficos na saúde cardiovascular. OBJETIVOS: Este estudo avaliou os efeitos agudos de 500 mL de suco de beterraba rico em nitrato (SB; contendo 11,5mmol NO3­) na pressão arterial e na função endotelial em pacientes hipertensos tratados. MÉTODOS: Estudo cruzado, randomizado, controlado por placebo foi realizado em pacientes hipertensos tratados (n=37; mulheres=62%) que foram submetidos à avaliação clínica e nutricional, avaliação dos parâmetros hemodinâmicos centrais e reatividade microvascular. O nível de significância foi p<0,05. RESULTADOS: A média de idade foi 59±7 anos e das pressões sistólica e diastólica foi de 142±10/83±9 mmHg. Houve aumento significativo na taxa de viabilidade subendocárdica (RVSE; 149±25 vs. 165±30%, p<0,001) e redução na duração da ejeção (DE; 37±4 vs. 34±4%, p<0,001) na fase beterraba, mas nenhuma diferença significativa de RVSE na fase controle. O % de aumento na perfusão (155 vs. 159%, p=0,042) cresceu significativamente na fase beterraba, o que não foi observado na fase controle. Na fase beterraba, a alteração da RVSE apresentou correlação significativa com a alteração da área sob a curva de hiperemia reativa pós-oclusiva (ASC-HRPO) (r=0,45, p=0,012). A mudança na DE mostrou uma correlação significativa com pico de perfusão pós-intervenção (r=-0,37, p=0,031) e ASC-HRPO (r=-0,36, p=0,046). CONCLUSÃO: A ingestão aguda de SB por pacientes hipertensos resultou em melhora da função endotelial, que foi associada à maior viabilidade subendocárdica e desempenho na contração miocárdica.

The Validity and Reproducibility of the Flexicurve in the Evaluation of Cervical Spine Lordosis.

OBJECTIVE: The purpose of this study was to measure the validity and reliability of flexicurve measurements of cervical curvature in the sagittal plane in adults. METHODS: One hundred thirteen adults were assessed in the seated position with flexicurve radiographs. Two groups were measured: (1) the validity group (n = 55), and (2) the reliability group (n = 58). Both groups were subdivided into 3 subgroups according to body mass index: underweight, normal weight, and overweight. Radiographs were simultaneously taken with flexicurve molded on the cervical spine. Pearson's correlation and the root mean square error were used for the concurrent validity. The reliability of the flexicurve was assessed by 3 raters using the intraclass correlation coefficient (ICC), the standard error of the measurement (SEM), and minimal detectable change (MDC). RESULTS: For the concurrent validity, a high correlation (r = 0.570, P < .001, root mean square error = 9.8°), and excellent results were obtained for intra-rater (ICC = 0.771, P < .001, SEM = 4.4°, MDC = 8.6°) and inter-rater (ICC = 0.775, P < .001, SEM = 4.3°, MDC = 8.5°) reliability. The subgroups had different results, whereas the underweight subgroup consistently had the best results. CONCLUSION: These findings suggest that the flexicurve can be a valid instrument for evaluating the curvature of the cervical spine in the sagittal plane in adults classified according to the body mass index as underweight and normal weight. Reliable measurements were provided for its use whether by the same or different raters. The flexicurve can be recommended for use both in clinical practice and in research settings as long as the suggested protocol is followed.

Oral magnesium supplementation improves endothelial function and attenuates subclinical atherosclerosis in thiazide-treated hypertensive women.

BACKGROUND: Epidemiological studies demonstrate an inverse association between serum magnesium and incidence of cardiovascular disease. Diuretics commonly cause hypomagneseamia. METHOD: We evaluated effects of magnesium supplementation on blood pressure (BP) and vascular function in thiazide-treated hypertensive women in a randomized, double-blind, clinical trial. Hypertensive women (40-65 years) on hydrochlorothiazide and mean 24-h BP at least 130/80 mmHg were divided into placebo and supplementation (magnesium chelate 600 mg/day) groups. Patients were evaluated for nutritional and biochemical parameters, office and ambulatory blood pressure monitoring, brachial flow-mediated dilatation (FMD), peripheral arterial tonometry, assessment of carotid intima-media thickness, central hemodynamic parameters and pulse wave velocity at inclusion and after 6-month follow-up. RESULTS: The magnesium group had a significant reduction in SBP (144 ±â€Š17 vs. 134 ±â€Š14 mmHg, P = 0.036) and DBP (88 ±â€Š9 vs. 81 ±â€Š8 mmHg, P = 0.005) at 6 months, without effect on plasma glucose, lipids, or arterial stiffness parameters. The placebo group showed a significant increase in carotid intima-media thickness (0.78 ±â€Š0.13 vs. 0.89 ±â€Š0.14 mm, P = 0.033) without change in the magnesium group (0.79 ±â€Š0.16 vs. 0.79 ±â€Š0.19 mm, P = 0.716) after 6 months. The magnesium group demonstrated a significant increase in variation of FMD vs. the placebo group (+3.7 ±â€Š2.1 vs. 2.4 ±â€Š1.2%, P = 0.015). There was a significant correlation between the intracellular magnesium variation and FMD (r = 0.44, P = 0.011). CONCLUSION: Magnesium supplementation was associated with better BP control, improved endothelial function and amelioration of subclinical atherosclerosis in these thiazide-treated hypertensive women.

Omega-3 fatty acids supplementation improves endothelial function and arterial stiffness in hypertensive patients with hypertriglyceridemia and high cardiovascular risk.

Association between hypertriglyceridemia and cardiovascular (CV) disease is still controversial. The purpose of this study was to compare omega-3 and ciprofibrate effects on the vascular structure and function in low and high CV risk hypertensive patients with hypertriglyceridemia. Twenty-nine adults with triglycerides 150-499 mg/dL were divided into low (<7.5%) and high (≥7.5%) CV risk, randomized to receive omega-3 fatty acids 1800 mg/d or ciprofibrate 100 mg/d for 12 weeks. Treatment was switched after 8-week washout. Clinical evaluation and vascular tests were assessed at baseline and after intervention. Peripheral (131 ± 3 to 125 ± 3 mm Hg, P < .05) and aortic (124 ± 3 to 118 ± 2 mg/dL, P < .05) systolic blood pressure were decreased by ciprofibrate in low-risk patients. In high-risk patients, pulse wave velocity was reduced (10.4 ± 0.4 to 9.4 ± 0.3 m/s, P < .05) and flow-mediated dilation was increased (11.1 ± 1.6 to 13.5 ± 1.2%, P < .05) by omega-3. In conclusion, omega-3 improved arterial stiffness and endothelial function, pointing out the beneficial effect of this therapy on vascular aging, in high-risk patients.

Renal cortex remodeling in streptozotocin-induced diabetic spontaneously hypertensive rats treated with olive oil, palm oil and fish oil from Menhaden.

We studied the effects of edible oils intake on the renal cortical structure of streptozotocin-induced diabetic (Db) and non-diabetic spontaneously hypertensive rats (SHR). Male SHR divided into 5 groups were studied during 6 weeks: one non-diabetic SHR group and four diabetic SHR groups (three groups received by gavage olive, palm or fish oil). Kidneys were analyzed by light microscopy and stereology. Oils intake did not change the plasma glucose levels. The blood pressure (BP) was lower in SHR-Db than in SHR, but SHR-Db-fish oil showed the lowest BP. Creatinine clearance was different between diabetic SHR and non-diabetic SHR, but not between treated SHR-Db and untreated SHR-Db. The renal cortex showed scars surrounding obsolete glomeruli with inflammatory infiltrate mainly in untreated SHR-Db. The olive oil, palm oil and mainly fish oil intake retard the usual loss of glomeruli and attenuate the renal cortex adverse remodeling of Db and non-Db SHR.

The influence of dietary nucleotides and long-chain polyunsaturated fatty acids on the incorporation of [3H] arachidonic acid on experimental liver cirrhosis

The purposes of this study were to determine: a) the incorporation of labeled [3H] arachidonic on the intestinal mucosa, the liver and plasma, after 1,3 and 5 hours of administration, b) preferential incorporation by different tissues, c)and the effects on experimental rats with thioacetamide-induced cirrhosis, after four weeks of dietary supplementatión with nucleotides and long-chain polyunsaturated fatty acids. 209 female Winstar rats were divided into two groups (control and TAA group). The TAA group was given 300 mg of thioacetamide/L, in their drinking water for four months. After this period, a sample of 6 rats were taken from each group and examined, to evaluate the biochemical and histological changes of the experimental model, and 36 rats were taken to determine the incorporation of radioactivity by the groups. The rest of the animals were divided into four subgroups. Each group, receiving a supplementary diet with only long-chaing polyunsaturated fatty acids and/or nucleotides or neither, for 4 weeks. After four months of thioacetamide, the incorporation of the [3H] arachidonic acid showed: a) an increased within 3 h in the intestinal mucosa, b) a decreased in the liver after 3 to 5 h, c) and a drastic decrease in the plasma after 3 to 5 h. With a dietary supplementation of long-chaing polyunsaturated fatty acids and nucleotides combined, there was a decrease of acumulate [3H] arachidonic acid in the intestine and a increase in the liver and plasma. The simultaneous supply of dietary polyunsaturated fatty acids and nucleotides was beneficial in the reversal of liver cirrhosis