Vasodilatation – ABC CARDIOL

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Original Article

Antihypertensive Activity of Sauromatum guttatum Mediated by Vasorelaxation and Myocardial Depressant Effects

Bibi Rabia et al. Umme Salma Kashif Bashir Taous Khan Abdul Jabbar Shah

Abstract

Background:

Sauromatum guttatum (S. guttatum) is used in the treatment of blood disorders and reportedly has a spasmolytic activity through Ca²⁺channel inhibition.

Objectives:

The aim of this study was to investigate the antihypertensive potential of S. guttatum in high salt-induced hypertensive Sprague-Dawley (SD) rat model (HSHRs).

Methods:

SD rats were divided into normotensive, hypertensive, S. guttatum and verapamil treated groups. S. guttatum crude extract (Sg.Cr) (100, 150 and 300 mg/kg/day) and verapamil (5, 10 and 15 mg/kg/day) were administered orally along with NaCl. Aortic rings and right atrial strips from normotensive rats were used to investigate the underlying mechanisms. The level of statistical significance was set at 5%.

Results:

Mean arterial pressure decreased in the Sg.Cr and verapamil-treated hypertensive groups in a dose-dependent manner (p < 0.001). In the vascular reactivity study, acetylcholine induced relaxations with an EC₅₀value of 0.6 µ g/mL (0.3–1.0) in Sg.Cr-treated hypertensive rats (300 mg/kg), suggesting endothelial preservation. In isolated normotensive rat aorta, Sg.Cr-treated rats showed vasorelaxation with an EC₅₀value of 0.15 mg/mL (0.10-0.20), ablated by endothelial denudation or pretreatment with_L-NAME and atropine. Sg.Cr treatment caused relaxation against high K⁺-induced contractions, like verapamil. Sg.Cr showed negative inotropic (82%) and chronotropic effects (56%) in isolated rat atrial preparations reduced with atropine. The phytochemical investigation indicated presence of alkaloids, flavonoids and tannins.

Conclusion:

S. guttatum has a vasodilatory effect through endothelial function preservation, muscarinic receptor-mediated NO release and Ca²⁺movement inhibition, while atrial myocardial depressant effect can be linked to the muscarinic receptor. These findings provide pharmacological base for using S. guttatum extract as an antihypertensive medication.

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Review Article

Evaluation of Myocardial Perfusion by Computed Tomography – Principles, Technical Background and Recommendations

Tiago Augusto Magalhães et al. Roberto Caldeira Cury Rodrigo Julio Cerci José Rodrigues Parga Filho … Ilan Gottlieb Marcelo Souto Nacif Ibraim Masciarelli Pinto Carlos Eduardo Rochitte Fabio Vilas-Boas Paulo R. Schvartzman

Abstract

Coronary computed tomography angiography (CCTA) has gained a prominent role in the evaluation of coronary artery disease. However, its anatomical nature does not allow the evaluation of the functional repercussion of coronary obstructions. It has been made possible to evaluate Myocardial computed tomography perfusion (Myocardial CTP) recently, based on myocardial contrast changes related to coronary stenoses. Several studies have validated this technique against the anatomical reference method (cardiac catheterization) and other functional methods, including myocardial perfusion scintigraphy and fractional flow reserve. The Myocardial CTP is performed in conjunction with the CCTA, a combined analysis of anatomy and function. The stress phase (with assessment of myocardial perfusion) can be performed before or after the resting phase (assessment of resting perfusion and coronary arteries), and different acquisition parameters are proposed according to the protocol and type of equipment used. Stressors used are based on coronary vasodilation (e.g. dipyridamole, adenosine). Image interpretation, similar to other perfusion assessment methods, is based on the identification and quantification of myocardial perfusion defects. The integration of both perfusion and anatomical findings is fundamental for the examination interpretation algorithm, allowing to define if the stenoses identified are hemodynamically significant and may be related to myocardial ischemia.

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IJCS

Original Article

Antioxidant and Vasodilatory Action of Grape Juices Produced in Different Regions of Brazil

José Britto Junior et al. Karla Carneiro Siqueira Leite Eric de Souza Gil Matheus Lavorenti Rocha

Abstract

Background:

Grapes and its derivatives (wines and juices) are rich in polyphenols that have high antioxidant and vasodilator capacity. These biological activities may vary in the juices marketed and produced in different regions of Brazil.

Objectives:

To determine the antioxidant and vasorelaxant effects of grape juice samples produced in different regions of Brazil.

Methods:

The content of phenolic compounds and antioxidant capacity were evaluated by the methods of Folin-Ciocalteau, DPPH, ABTS and a new electroanalytical approach (differential pulse voltammetry – DPV). Vasodilator effects were analyzed in isolated aorta from rats in an organ bath.

Results:

The samples from RJ and SP presented respectively the higher and lower phenolic content and also antioxidant capacity by the methods used (ABTS and DPPH). The results of the electrochemical index corroborate to the other tests, with the best results to RJ (21.69 ± 3.15 µA/V) and worse to the SP sample (11.30 ± 0.52 µA/V). In the vascular reactivity studies, the relaxation induced by each sample presented more distinct differences, following the order: RJ (87.9 ± 4.8%) > RS1 (71.6 ± 8.6%) > GO (56.2 ± 7.2%) > SP (39.9 ± 7.8%) > PR (39.4 ± 9.5%) > RS2 (19.5 ± 6.2%). Inhibition of endothelial NO practically abolished (p < 0.001) the relaxation for all samples, except one.

Conclusion:

The phenolic content and antioxidant capacity vary greatly among samples. The results obtained for the order of antioxidant activity were: RJ > RS1 > GO > RS2 > PR > SP. The juices were able to induce vascular relaxation at quite varied levels, and the RJ sample the most effective. The L-NAME practically blocked all samples except one (RS2).

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Original Article

Vasodilation and Reduction of Systolic Blood Pressure after One Session of High-Intensity Interval Training in Patients With Heart Failure with Preserved Ejection Fraction

Juliana Beust de Lima et al. Anderson Donelli da Silveira Marco Aurélio Lumertz Saffi Márcio Garcia Menezes … Diogo Silva Piardi Leila Denise Cardoso Ramos Ramm Maurice Zanini Rosane Maria Nery, Ricardo Stein

Abstract

Background:

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial syndrome characterized by a limited exercising capacity. High-intensity interval training (HIIT) is an emerging strategy for exercise rehabilitation in different settings. In patients with HFpEF, HIIT subacute effects on endothelial function and blood pressure are still unknown.

Objective:

To evaluate the subacute effect of one HIIT session on endothelial function and blood pressure in patients with HFpEF.

Methods:

Sixteen patients with HFpEF underwent a 36-minute session of HIIT on a treadmill, alternating four minutes of high-intensity intervals with three minutes of active recovery. Brachial artery diameter, flow-mediated dilation, and blood pressure were assessed immediately before and 30 minutes after the HIIT session. In all analyses, p <0.05 was considered statistically significant.

Results:

There was an increase in brachial artery diameter (pre-exercise: 3.96 ± 0.57 mm; post-exercise: 4.33 ± 0.69 mm; p < 0.01) and a decrease in systolic blood pressure (pre-exercise: 138 ± 21 mmHg; post-exercise: 125 ± 20 mmHg; p < 0.01). Flow-mediated dilation (pre-exercise: 5.91 ± 5.20%; post-exercise: 3.55 ± 6.59%; p = 0.162) and diastolic blood pressure (pre-exercise: 81 ± 11 mmHg; post-exercise: 77 ± 8 mmHg; p = 1.000) did not change significantly. There were no adverse events throughout the experiment.

Conclusions:

One single HIIT session promoted an increase in brachial artery diameter and reduction in systolic blood pressure, but it did not change flow-mediated dilation and diastolic blood pressure.

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Original Article

Effects of a Single Bout of Resistance Exercise in Different Volumes on Endothelium Adaptations in Healthy Animals

Marcelo Mendonça Mota et al. Tharciano Luiz Teixeira Braga da Silva Fabricio Nunes Macedo Thássio Ricardo Ribeiro Mesquita … Lucindo José Quintans Júnior Valter Joviniano de Santana-Filho Sandra Lauton-Santos Márcio Roberto Viana Santos

Abstract

Background:

Resistance exercise (RE) has been recommended for patients with cardiovascular diseases. Recently, a few studies have demonstrated that the intensity of a single bout of RE has an effect on endothelial adaptations to exercise. However, there is no data about the effects of different volumes of RE on endothelium function.

Objective:

The aim of the study was to evaluate the effects of different volumes of RE in a single bout on endothelium-dependent vasodilatation and nitric oxide (NO) synthesis in the mesenteric artery of healthy animals.

Methods:

Male Wistar rats were divided into three groups: Control (Ct); low-volume RE (LV, 5 sets x 10 repetitions) and high-volume RE (HV, 15 sets x 10 repetitions). The established intensity was 70% of the maximal repetition test. After the exercise protocol, rings of mesenteric artery were used for assessment of vascular reactivity, and other mesenteric arteries were prepared for detection of measure NO production by DAF-FM fluorescence. Insulin responsiveness on NO synthesis was evaluated by stimulating the vascular rings with insulin (10 nM).

Results:

The maximal relaxation response to insulin increased in the HV group only as compared with the Ct group. Moreover, the inhibition of nitric oxide synthesis (L-NAME) completely abolished the insulin-induced vasorelaxation in exercised rats. NO production showed a volume-dependent increase in the endothelial and smooth muscle layer. In endothelial layer, only Ct and LV groups showed a significant increase in NO synthesis when compared to their respective group under basal condition. On the other hand, in smooth muscle layer, NO fluorescence increased in all groups when compared to their respective group under basal condition.

Conclusions:

Our results suggest that a single bout of RE promotes vascular endothelium changes in a volume-dependent manner. The 15 sets x 10 repetitions exercise plan induced the greatest levels of NO synthesis.

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IJCS

Review Article

Methods of Endothelial Function Assessment: Description and Applications

Amanda Sampaio Storch et al. João Dario de Mattos Renata Alves Iuri dos Santos Galdino Helena Naly Miguens Rocha

Introduction

The endothelium is a monolayer of cells, called endothelial cells, that lines the interior of blood vessels, including arteries, veins and cardiac chambers, acting as a protective layer between circulating blood and other tissues. The endothelium is crucial for the control of vascular homeostasis, and is involved in the regulation of intracellular signaling, vascular tonus and permeability, coagulation cascade and angiogenesis, among others. One of the main activities of the endothelium is the release of autocrine and paracrine substances in response to stimuli. Injuries to the endothelium trigger an inflammatory response with participation of several cell types – lymphocytes, monocytes, platelets and smooth muscle cells – culminating in endothelial cell dysfunction, stiffness of vessel wall and atherosclerotic plaque formation.

Endothelial dysfunction is an early, key characteristic of development and progression of atherosclerotic plaque and subsequent complications. This is characterized by a reduced bioavailability of endothelium-derived vasodilators, such as nitric oxide (NO), along with a relative or absolute increase in available vasoconstrictors. Such unbalanced condition impairs the endothelium-dependent vasodilation, a functional marker of endothelial dysfunction.

[…]

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Original Article

Jabuticaba-Induced Endothelium-Independent Vasodilating Effect on Isolated Arteries

Daniela Medeiros Lobo de Andrade et al. Leonardo Luis Borges Ieda Maria Sapateiro Torres Edemilson Cardoso da Conceição Matheus Lavorenti Rocha

Abstract

Background:

Despite the important biological effects of jabuticaba, its actions on the cardiovascular system have not been clarified.

Objectives:

To determine the effects of jabuticaba hydroalcoholic extract (JHE) on vascular smooth muscle (VSM) of isolated arteries.

Methods:

Endothelium-denuded aortic rings of rats were mounted in isolated organ bath to record isometric tension. The relaxant effect of JHE and the influence of K⁺ channels and Ca²⁺ intra- and extracellular sources on JHE-stimulated response were assessed.

Results:

Arteries pre-contracted with phenylephrine showed concentration-dependent relaxation (0.380 to 1.92 mg/mL). Treatment with K⁺ channel blockers (tetraethyl-ammonium, glibenclamide, 4-aminopyridine) hindered relaxation due to JHE. In addition, phenylephrine-stimulated contraction was hindered by previous treatment with JHE. Inhibition of sarcoplasmic reticulum Ca²⁺ ATPase did not change relaxation due to JHE. In addition, JHE inhibited the contraction caused by Ca²⁺ influx stimulated by phenylephrine and KCl (75 mM).

Conclusion:

JHE induces endothelium-independent vasodilation. Activation of K⁺ channels and inhibition of Ca²⁺ influx through the membrane are involved in the JHE relaxant effect.

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Original Article

Effects of One Resistance Exercise Session on Vascular Smooth Muscle of Hypertensive Rats

Tharciano Luiz Teixeira Braga da Silva et al. Marcelo Mendonça Mota Milene Tavares Fontes João Eliakim dos Santos Araújo … Vitor Oliveira Carvalho Leonardo Rigoldi Bonjardim Márcio Roberto Viana Santos

Abstract

Background:

Hypertension is a public health problem and increases the incidence of cardiovascular diseases.

Objective:

To evaluate the effects of a resistance exercise session on the contractile and relaxing mechanisms of vascular smooth muscle in mesenteric arteries of N^G-nitro L-arginine methyl ester (L-NAME)-induced hypertensive rats.

Methods:

Wistar rats were divided into three groups: control (C), hypertensive (H), and exercised hypertensive (EH). Hypertension was induced by administration of 20 mg/kg of L-NAME for 7 days prior to experimental protocols. The resistance exercise protocol consisted of 10 sets of 10 repetitions and intensity of 40% of one repetition maximum. The reactivity of vascular smooth muscle was evaluated by concentration‑response curves to phenylephrine (PHEN), potassium chloride (KCl) and sodium nitroprusside (SNP).

Results:

Rats treated with L-NAME showed an increase (p < 0.001) in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) compared to the initial period of induction. No difference in PHEN sensitivity was observed between groups H and EH. Acute resistance exercise reduced (p < 0.001) the contractile response induced by KCl at concentrations of 40 and 60 mM in group EH. Greater (p < 0.01) smooth muscle sensitivity to NPS was observed in group EH as compared to group H.

Conclusion:

One resistance exercise session reduces the contractile response induced by KCl in addition to increasing the sensitivity of smooth muscle to NO in mesenteric arteries of hypertensive rats.

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Artigo Original

Resistance training controls arterial blood pressure in rats with L-NAME- induced hypertension

Ayslan Jorge Santos de Araujo et al. Anne Carolline Veríssimo dos Santos Karine dos Santos Souza Marlúcia Bastos Aires … Valter Joviniano Santana-Filho Emerson Ticona Fioretto Marcelo Mendonça Mota Márcio Roberto Viana Santos

BACKGROUND: Arterial hypertension is a multifactorial chronic condition caused by either congenital or acquired factors. OBJECTIVE: To evaluate the effects of Resistance Training (RT) on arterial pressure, and on vascular reactivity and morphology, of L-NAME-treated hypertensive rats. METHODS: Male Wistar rats (200 – 250 g) were allocated into Sedentary Normotensive (SN), Sedentary Hypertensive (SH) and Trained Hypertensive (TH) groups. Hypertension was induced by adding L-NAME (40 mg/Kg) to the drinking water for four weeks. Arterial pressure was evaluated before and after RT. RT was performed using 50% of 1RM, 3 sets of 10 repetitions, 3 times per week for four weeks. Vascular reactivity was measured in rat mesenteric artery rings by concentration-response curves to sodium nitroprusside (SNP); phenylephrine (PHE) was also used for histological and stereological analysis. RESULTS: Resistance training inhibited the increase in mean and diastolic arterial pressures. Significant reduction was observed in Rmax (maximal response) and pD2 (potency) of PHE between SH and TH groups. Arteries demonstrated normal intima, media and adventitia layers in all groups. Stereological analysis demonstrated no significant difference in luminal, tunica media, and total areas of arteries in the SH and TH groups when compared to the SN group. Wall-to-lumen ratio of SH arteries was significantly different compared to SN arteries (p<0.05) but there was no difference when compared to TH arteries. CONCLUSIONS: RT was able to prevent an increase in blood pressure under the conditions in this study. This appears to involve a vasoconstrictor regulation mechanism and maintenance of luminal diameter in L-NAME induced hypertensive rats.

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Artigo Original

Flow-mediated dilatation in the differential diagnosis of preeclampsia syndrome

Edson Vieira da Cunha Filho et al. Carolina Mohr Breno José Acauan Filho Giovani Gadonski … Leticia Germany Paula Ivan Carlos Ferreira Antonello Carlos Eduardo Poli-de-Figueiredo Bartira Ercilia Pinheiro-da-Costa

BACKGROUND: The preeclampsia syndrome is associated with endothelial dysfunction and the differential diagnosis between pure preeclampsia (PE) and superimposed preeclampsia (SPE) can be only be attained 12 weeks after delivery. OBJECTIVE: To compare the assessment of endothelial function through flow-mediated dilatation in pregnant women with pure preeclampsia and superimposed preeclampsia. METHODS: The flow-mediated dilatation of the brachial artery was carried out according to the recommendations of the International Brachial Artery Reactivity Task Force in pregnant women with preeclampsia syndrome. PE (n=14) and SPE (n=13) were diagnosed in the postpartum period according to the definitions of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy. RESULTS: The median of the flow-mediated dilatation (FMD) in SPE (6.0%; 1.9-10.3) was decreased in comparison with the PE (13.6%;4.4-17.1), an apparently relevant difference , but not statistically significant (p = 0.08). The FMD < 10% was detected in 30.8% of the PE cases and in 69.2% of the SPE cases (p = 0.057). Significant differences could not be detected in the morphology of the uterine arteries between the PE and SPE cases through the Doppler spectrum. CONCLUSION: The FMD of the brachial artery of patients with preeclampsia syndrome was not capable of differentiating between PE and SPE. However, the data suggest that SPE is associated with worse endothelial function I comparison to PE.

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