Cardioprotective Effects of the 4-Week Aerobic Running Exercises Before Treatment with Doxorubicin in Rats

Doxorubicin is associated with cardiotoxicity, and physical exercise seeks to minimize the toxic effects of doxorubicin through physiological cardiac remodeling, as well as the reduction of oxidative stress, evidenced by previous studies. This study aimed to analyze whether running training before treatment with doxorubicin influences tolerance to physical exertion and cardiotoxicity. Thirty-nine male Wistar rats, aged 90 days and weighing between 250 and 300 g, were divided into 4 groups: Control (C), Doxorubicin (D), Trained (T), and Trained + Doxorubicin (TD). Animals in groups T and DT were submitted to treadmill running for 3 weeks, 5 times a week at 18 m/min for 20-30 min before treatment with doxorubicin. Animals in groups D and DT received intraperitoneal injections of doxorubicin hydrochloride three times a week for two weeks, reaching a total cumulative dose of 7.50 mg/kg. Our results show an increase in total collagen fibers in the D group (p = 0.01), but no increase in the TD group, in addition to the attenuation of the number of cardiac mast cells in the animals in the TD group (p = 0.05). The animals in the TD group showed maintenance of tolerance to exertion compared to group D. Therefore, running training attenuated the cardiac damage caused by the treatment with doxorubicin, in addition to maintaining the tolerance to exertion in the rats.

Leucine Supplementation Improves Effort Tolerance of Rats With Hyperthyroidism

Leucine is a regulator of protein metabolism in vivo and information on its action on effort tolerance of both animals and humans with hyperthyroidism is scarce. The objective of the present study was to verify the influence of leucine supplementation on the effort tolerance of Wistar rats with experimental hyperthyroidism. 40 animals were divided into four groups of ten: control (C), hormone (H), leucine (L), and hormone + leucine (HL). Hyperthyroidism was induced by daily administration of 20 μ⋅g100 g^-1 of levothyroxine sodium in aqueous suspension by gavage. Leucine was supplemented by adding 5% of the amino acid to the conventional feed. The animals’ blood was collected by cardiac puncture to analyze TSH, T4, and T3 levels. The effort tolerance was determined by the swimming test with a 7% load attached to animals’ tails. Statistical analysis was performed using the Shapiro-Wilk normality test, followed by the analysis of variance (ANOVA) of repeated measures of two factors (treatment × time) and Tukey post hoc, with a significance level of p < 0.05. Administering thyroid hormone increased the swimming performance of rats after 14 and 21 days, but with a drop in performance at 28 days. The HL group, on the other hand, had a significantly higher swimming performance compared to the other groups after 28 days of treatment. Leucine supplementation associated with the experimental model of hyperthyroidism improved the performance of rats in a swimming test after 28 days of treatment.

High-density lipoprotein-cholesterol functionality and metabolic syndrome: Protocol for review and meta-analysis

INTRODUCTION

The prevalence of metabolic syndrome (MetS) and MetS-related stroke is set to increase dramatically in coming decades. MetS is a complex disease that includes endothelial dysfunction, insulin resistance, diabetes, hypertension, ectopic obesity, and dyslipidaemia and an increased risk of cardiovascular events. One function of high-density lipoprotein (HDL) cholesterol (HDL-C) is the cholesterol-efflux pathway, which is the pathway where cholesterol is removed from macrophages within the arterial walls back into the bloodstream and out to the liver. As one of the key functions of HDL, their hypothesis was that if they could measure HDL-C-efflux capacity, they would have a better handle on the role of HDL in atherosclerosis. However, there are no systematic analyses or well-conducted meta-analyses to evaluate the relationship between HDL-C functionality and MetS. The aim of this study is to examine this association of HDL-C functionality with MetS in different ages and sex.

METHODS AND ANALYSIS

The update systematic review and meta-analysis will be conducted using published studies that will be identified from electronic databases (i.e., PubMed, EMBASE, Web of Science, and Google Scholar). Studies that examined the association between HDL-C functionality and MetS; focused on cohort, case-control, and cross-sectional studies; were conducted among in adults aged 40 to 70 years; provided sufficient data for calculating odds ratio or relative risk with a 95% confidence interval; were published as original articles written in English or other languages; and have been published until January 2018 will be included. Study selection, data collection, quality assessment, and statistical syntheses will be conducted based on discussions among investigators.

ETHICS AND DISSEMINATION

Ethics approval was not required for this study because it was based on published studies. The results and findings of this study will be submitted and published in a scientific peer-reviewed journal.

TRIAL REGISTRATION NUMBER

PROSPERO (CRD42018083465).

Epicardial adipose tissue and metabolic syndrome: An update protocol for systematic review and meta-analysis

BACKGROUND

The prevalence of metabolic syndrome (MetS) and MetS-related stroke is set to increase dramatically in coming decades. MetS is a complex disease that includes endothelial dysfunction, insulin resistance, diabetes, hypertension, ectopic obesity, and dyslipidaemia, and an increased risk of cardiovascular events. However, there are no systematic analyses, or well-conducted meta-analyses to evaluate the relationship between epicardial adipose tissue (EAT) and (MetS). The aim of this study is to examine this association of EAT with MetS in different ages and sex.

METHODS

The update systematic review, and meta-analysis will be conducted using published studies that will be identified from electronic databases (ie, PubMed, EMBASE, Web of Science, and Google Scholar. Studies that firstly, examined the association between EAT and MetS, secondly, focus on cohort, case-control, and cross-sectional studies, thirdly, were conducted among in adults aged between 40 and 70 years, fourth, provided sufficient data for calculating ORs or relative risk with a 95% CI, fifth, were published as original articles written in English or other languages, and sixth, have been published until January year 2018 will be included. Study selection, data collection, quality assessment, and statistical syntheses will be conducted based on discussions among investigators.

RESULTS

Ethics approval was not required for this study because it was based on published studies. The results and findings of this study will be submitted and published in a scientific peer-reviewed journal. This study will provide a high quality synthesis on the association of EAT and MetS.

CONCLUSION

This systematic review will provide evidence to assess whether there is a strong association of EAT and MetS, and its components.

Epicardial adipose tissue and carotid artery disease: Protocol for systematic review and meta-analysis

BACKGROUND

Atherosclerosis is now widely recognized as a multifactorial disease with outcomes that arise from complex factors such as plaque components, blood flow, and inflammation. Epicardial adipose tissue (EAT) is a metabolically active fat depot, abundant in proinflammatory cytokines, and has been correlated with the extent and severity of carotid artery disease (CD). The locations most frequently affected by carotid atherosclerosis are the proximal internal carotid artery (ie, the origin) and the common carotid artery bifurcation. Progression of atheromatous plaque at the carotid bifurcation results in luminal narrowing, often accompanied by ulceration. However, there are no systematic analyses or well-conducted meta-analyses to evaluate the relationship between EAT and CD. The aim of this study is to examine this association of EAT with CD in different ages and sex.

METHODS

This systematic review and meta-analysis will be conducted using published studies that will be identified from electronic databases (ie, PubMed, EMBASE, Web of Science, and Google Scholar. Studies that (1) examined the association between EAT and CD, (2) focus on cohort, case-control and cross-sectional studies, (3) will conducted among in adults aged 40 to 70 years, (4) provided sufficient data for calculating ORs or relative risk with a 95% CI, (5) will published as original articles written in English or other languages, and (6) have been published until January 2018 will be included. Study selection, data collection, quality assessment and statistical syntheses will be conducted based on discussions among investigators.

RESULTS

We propose the current protocol to evaluate the evaluation of EAT with ED.

CONCLUSION

This systematic review will not need ethical approval, because it does not involve human beings. The results and findings of this study will be submitted and published in a scientific peer-reviewed journal.

ETHICS AND DISSEMINATION

Ethics approval was not required for this study because it was based on published studies. The results and findings of this study will be submitted and published in a scientific peer-reviewed journal.

TRIAL REGISTRATION NUMBER

PROSPERO (CRD42018083458).

Increased Dietary Leucine Reduces Doxorubicin-Associated Cardiac Dysfunction in Rats

Cardiotoxicity is one of the most significant adverse effects of the oncologic treatment with doxorubicin, which is responsible for a substantial morbid and mortality. The occurrence of heart failure with ventricular dysfunction may lead to severe cardiomyopathy and ultimately to death. Studies have focused on the effects of leucine supplementation as a strategy to minimize or revert the clinical condition of induced proteolysis by several clinical onsets. However, the impact of leucine supplementation in heart failure induced by doxorubicin is unknown. Therefore, the objective of this work is to evaluate the effects of leucine supplementation on the cardiotoxicity in the heart of rats treated with doxorubicin. Rats treated with a 7.5 mg/kg cumulative dose of doxorubicin for 14 days presented a dilatation of the left ventricle (LV), and a reduction of the ejection fraction (FE). The 5% supplementation of leucine in the rats' food prevented the malfunctioning of the LV when administered with doxorubicin. Some alterations in the extracellular matrix remodeling were confirmed by the increase of collagen fibers in the doxorubicin group, which did not increase when the treatment was associated with leucine supplementation. Leucine attenuates heart failure in this experimental model with doxorubicin. Such protection is followed by the maintenance of interstitial collagen fibers.

Hypertrophic response of the association of thyroid hormone and exercise in the heart of rats

Background

Cardiac hypertrophy is a component of cardiac remodeling occurring in response to an increase of the activity or functional overload of the heart.

Objective

Assess hypertrophic response of the association of thyroid hormone and exercise in the rat heart.

Methods

We used 37 Wistar rats, male, adults were randomly divided into four groups: control, hormone (TH), exercise (E), thyroid hormone and exercise (H + E); the group received daily hormone levothyroxine sodium by gavage at a dose of 20 μg thyroid hormone/100g body weight, the exercise group took swimming five times a week, with additional weight corresponding to 20% of body weight for six weeks; in group H + E were applied simultaneously TH treatment groups and E. The statistics used was analysis of variance, where appropriate, by Tukey test and Pearson correlation test.

Results

The T4 was greater in groups TH and H + E. The total weight of the heart was greater in patients who received thyroid hormone and left ventricular weight was greater in the TH group. The transverse diameter of cardiomyocytes increased in groups TH, E and H + E. The percentage of collagen was greater in groups E and H + E Correlation analysis between variables showed distinct responses.

Conclusion

The association of thyroid hormone with high-intensity exercise produced cardiac hypertrophy, and generated a standard hypertrophy not directly correlated to the degree of fibrosis.