Magnus Benetti

Taurine supplementation decreases oxidative stress in skeletal muscle after eccentric exercise

Infrequent exercise, typically involving eccentric actions, has been shown to cause oxidative stress and to damage muscle tissue. High taurine levels are present in skeletal muscle and may play a role in cellular defences against free radical‐mediated damage. This study investigates the effects of taurine supplementation on oxidative stress biomarkers after eccentric exercise (EE). Twenty‐four male rats were divided into the following groups (n = 6): control; EE; EE plus taurine (EE + Taurine); EE plus saline (EE + Saline). Taurine was administered as a 1‐ml 300 mg kg−1 per body weight (BW) day−1 solution in water by gavage, for 15 consecutive days. Starting on the 14th day of supplementation, the animals were submitted to one 90‐min downhill run session and constant velocity of 1·0 km h−1. Forty‐eight hours after the exercise session, the animals were killed and the quadriceps muscles were surgically removed. Production of superoxide anion, creatine kinase (CK) levels, lipoperoxidation, carbonylation, total thiol content and antioxidant enzyme were analysed. Taurine supplementation was found to decrease superoxide radical production, CK, lipoperoxidation and carbonylation levels and increased total thiol content in skeletal muscle, but it did not affect antioxidant enzyme activity after EE. The present study suggests that taurine affects skeletal muscle contraction by decreasing oxidative stress, in association with decreased superoxide radical production. Copyright

Effects of different physical training protocols on ventricular oxidative stress parameters in infarction-induced rats

AIM Physical exercise is important in the prevention and treatment of cardiovascular diseases. Nevertheless, controversy remains around type and intensity of effort required for significant biochemical protective changes. This study investigates two exercise protocols on ventricular oxidative parameters in rats post-infarction. MAIN METHODS Thirty-six 2-month-old male Wistar rats were divided in two groups (n=18): Sham and acute myocardial infarction (AMI) conducted by blocking the coronary artery. Thirty days after AMI, animals were divided in 6 subgroups (n=6): sham, sham+continuous training (60 min), sham+interval training, AMI, AMI+continuous training, and AMI+interval training. Training was conducted in water (30-32°C) 5 times a week for 6 weeks. Animals were sacrificed 48 h after the last exercise routine. Left ventricles were used for oxidative stress analyses (antioxidant enzyme activity and level, oxidative damage) and HIF1α and cit c oxidase expression. KEY FINDINGS After AMI, both exercise models decreased superoxide levels significantly. Training routines did not alter SOD expression and activity, though CAT expression increased with continuous training and GPX level diminished in both training groups, which coincided with the increase in GPX activity. Lipid damage decreased only in the continuous training group, while protein damage decreased only in the interval training group. Cytochrome C increased in both groups, while HIF-1 α dropped significantly after both exercise protocols. SIGNIFICANCE Significant improvement occurred in myocardium redox status in rats challenged with AMI after different training routines. However, continuous training seems to be more efficient in improving the parameters analyzed.

Oxidative Stress and Inflammatory Parameters After an Ironman Race

Objective: The aim of the present study was to investigate oxidative stress markers and inflammatory response in triathletes after an Ironman race (IR). Design: Descriptive research. Participants: Eighteen well-trained male triathletes (mean age, 34.7 ± 2.15 years; weight, 69.3 ± 1.9 kg; height, 1.81 ± 0.58 cm) participated in the study. Setting: Ironman Triathlon (3.8-km swim, 180-km cycle, 42.2-km run). Mean environmental conditions ranged from 20 to 25°C and from 79% to 85% relative humidity. Interventions: None. Main Outcome Measures: Before the race and up to 20 minutes after completing the full race, the weights and heights of volunteers were measured and a 10 mL blood sample was drawn from an antecubital vein. Aliquots of washed/lysed red blood cells and plasma/serum samples were stored at −80°C. Lipid peroxidation, protein carbonylation, superoxide dismutase and catalase activities, and cytokines levels [tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-10, and IL-1ra] were determined. Results: After the IR, the results showed a significant increase in TBARS levels (prerace = 1.15 ± 0.11; postrace = 1.98 ± 0.27), lipid hydroperoxide content (prerace = 0.75 ± 0.03; postrace = 1.46 ± 0.18), protein carbonylation (prerace = 0.67 ± 0.12; postrace = 2 0.15 ± 0.60), superoxide dismutase (prerace = 2.67 ± 0.62; postrace = 3.97 ± 1.48), and catalase (prerace = 1.48 ± 0.18; postrace = 2.84 ± 0.39). TNF-α, IL-6, and IL-10 were not detected at basal conditions, but all markers were significantly increased after the IR (TNF-α: prerace = ND and postrace = 67.47 ± 10.34; IL-6: prerace = ND and postrace = 55.41 ± 3.45; IL-10: prerace = ND and postrace = 122.53 ± 9.69; IL-1ra: prerace = 127.79 ± 25.65 and postrace = 259.51 ± 32.9). Conclusions: An Ironman race provokes significant alterations in oxidative stress and inflammatory parameters. Thus, more studies with other markers and different designs are needed to elucidate the cellular alterations induced by an IR.

Desenvolvimento e validação da versão em português da Escala de Barreiras para Reabilitação Cardíaca

BACKGROUND Cardiovascular diseases show high incidence and prevalence in Brazil; however, participation in Cardiac Rehabilitation (CR) is limited and has been poorly investigated in the country. The Cardiac Rehabilitation Barriers Scale (CRBS) was developed to assess the barriers to participation and adherence to CR. OBJECTIVE To translate, cross-culturally adapt and psychometrically validate CRBS to Brazilian Portuguese. METHODS Two independent initial translations were performed. After the reverse translation, both versions were reviewed by a committee. The new version was tested in 173 patients with coronary artery disease (48 women, mean age = 63 years). Of these, 139 (80.3%) participated in CR. Internal consistency was assessed by Cronbachs alpha, test-retest reliability by intraclass correlation coefficient (ICC) and construct validity by factor analysis. T-tests were used to assess criterion validity between participants and non-participants in CR. The applied test results were evaluated regarding patient characteristics (gender, age, health status and educational level). RESULTS The Brazilian Portuguese version of the CRBS had Cronbachs alpha of 0.88, ICC of 0.68 and disclosed five factors, most of which showed to be internally consistent and all were defined by the items. The mean score for patients in CR was 1.29 (SD = 0.27) and 2.36 for ambulatory patients (SD = 0.50) (p <0.001). Criterion validity was also supported by significant differences in total scores by gender, age and educational level. CONCLUSION The Brazilian Portuguese version of CRBS has shown adequate validity and reliability, which supports its use in future studies.

Physical exercise and endothelial dysfunction.

The role of the endothelium was considered mainly as a selective barrier for the diffusion of macromolecules from the lumen of blood vessels to the interstitial space. During the last 20 years, many other functions have been defined for the endothelium, such as the regulation of the vagal tonus, the promotion and inhibition of neovascular growth and the modulation of inflammation, of platelet aggregation and coagulation. This finding is considered one of the most important concepts in modern vascular biology. Currently, atherosclerosis is the prototype of the disease characterized in all its phases by an endothelial dysfunction, defined as an insufficient offer of nitric oxide (NO), which predisposes the endothelium to oxidative stress, inflammation, erosion and vasoconstriction. In this sense, several experimental studies have demonstrated that physical exercise is capable of restoring and improving the endothelial function. The impact of exercise on the endothelium has been broadly discussed. Considering its vasodilating effect and the risk factors, the possibility of treating coronary artery disease and its outcomes without the inclusion of physical exercise became unconceivable. However, the literature is still controversial regarding the intensity of physical effort that is necessary to cause significant protective alterations in endothelial functions. Moreover, the association between intense physical exercises and increased oxygen consumption, with a consequent increase in free radical formation, is also discussed.Se consideraba que el papel del endotelio era, sobre todo, de barrera selectiva para la difusion de macromoleculas de la luz de los vasos sanguineos al espacio intersticial. Durante los ultimos 20 anos, fueron definidas muchas otras funciones para el endotelio, como la regulacion del tono vagal, la promocion e inhibicion del crecimiento neovascular y la modulacion de la inflamacion, de la agregacion plaquetaria y de la coagulacion. Ese hallazgo es considerado uno de los mas importantes conceptos de la biologia vascular moderna. Actualmente, la aterosclerosis es el prototipo de la enfermedad caracterizada en todas sus fases por una disfuncion endotelial, que es definida como una oferta insuficiente de oxido nitrico (ON), el cual expone al endotelio a estres oxidativo, inflamacion, erosion y vasoconstriccion. En ese sentido, numerosos estudios experimentales han demostrado que el ejercicio fisico es capaz de restaurar y mejorar la funcion endotelial. El impacto del ejercicio en el endotelio viene siendo ampliamente discutido. Delante de su efecto vasodilatador y sobre los factores de riesgo, se volvio insostenible la hipotesis de tratamiento de la enfermedad arterial coronaria y de sus desenlaces sin la inclusion del ejercicio fisico. Entre tanto, la literatura aun es controvertida en cuanto a la intensidad de esfuerzo necesaria para provocar alteraciones protectoras significativas en la funcion endotelial. Aun la relacion entre ejercicios intensos y aumento en el consumo de oxigeno, con consecuente aumento en la formacion de radicales libres, tambien es discutida.

[Coronary heart disease, physical exercise and oxidative stress].

As doencas cardiovasculares (DCV) lideram os indices de morbidade e mortalidade no Brasil e no mundo, sendo a doenca arterial coronariana (DAC) a causa de um grande numero de mortes e de gastos em assistencia medica. Inumeros fatores de risco para a DAC estao diretamente relacionados a disfuncao endotelial. A presenca desses fatores de risco induz a diminuicao da biodisponibilidade de oxido nitrico (NO), o aumento da formacao de radicais livres (RL) e o aumento da atividade endotelial. Essas mudancas podem levar a uma capacidade vasodilatadora prejudicada. Inumeras intervencoes sao realizadas no tratamento da DAC, incluindo agentes farmacologicos, mudanca nos habitos alimentares, suplementacao nutricional e exercicio fisico regular, cujos efeitos beneficos sobre a funcao endotelial vem sendo demonstrados em experimentos com animais e humanos. Entretanto, a literatura ainda e controversa quanto a intensidade de esforco necessaria para provocar alteracoes protetoras significativas na funcao endotelial. Da mesma forma, exercicios intensos estao tambem relacionados ao aumento no consumo de oxigenio e ao consequente aumento na formacao de radicais livres de oxigenio (RLO).Cardiovascular diseases are the leaders in morbidity and mortality rates in Brazil and worldwide, being coronary heart disease (CHD) the cause of a large number of deaths and high expenditure on medical assistance. Quite a number of risk factors for CHD are directly related to endothelial dysfunction. Those risk factors induce decreased bioavailability of nitric oxide (NO), the increase of free radicals (FR), and increased endothelial activity. Those changes may lead to vasodilation impairment. Many interventions are performed to treat CHD. Pharmacological agents, a change in eating habits, nutritional supplements and physical exercise on a regular basis are some of those interventions. The benefits of physical exercise on a regular basis over endothelial function have been demonstrated in experiments with animals and humans. However, data in the literature are still controversial as to the required intensity level to result in significantly protective changes in endothelial function. Intense exercising is also related to higher oxygen consumption and to a resulting increase of oxygen free radicals (OFR).

Barriers to cardiac rehabilitation use in Canada versus Brazil.

PURPOSE: Despite its well-established benefits, cardiac rehabilitation (CR) is greatly underutilized globally. Barriers to its utilization have been identified in high-income countries. Given the growing epidemic of noncommunicable diseases in low- to middle-income countries, the identification of barriers to use of these low-cost interventions is warranted. The aim of this study was to describe and compare barriers to CR use in Brazilian and Canadian cardiac outpatients. METHODS: Two cardiac samples consisting of 237 Brazilian (recruited from 2 CR centers in southern Brazil) and 1434 Canadian (recruited from 11 community and academic hospitals in Ontario) outpatients were compared cross-sectionally. Barriers were assessed by using the Cardiac Rehabilitation Barriers Scale, psychometrically validated in English and Portuguese. Mann-Whitney U tests were used to compare barriers between samples. RESULTS: Overall, 139 (58.6%) Brazilian and 779 (54.3%) Canadian respondents were enrolled in CR. The mean total barriers score for Brazilian respondents was 1.71 ± 0.63, and 2.37 ± 1.0 (P < .01) for the Canadians. For 17 of 21 barriers, Canadians reported significantly greater barriers than Brazilians (P < .02). As their greatest barriers, Canadians rated already exercising at home or in the community and personal travel, while Brazilians identified distance to and cost of the CR program. CONCLUSION: Despite the significantly lower availability of CR in Brazil and the universal health care system in Canada, cardiac outpatients in Canada perceived significantly greater CR barriers. Arguably, however, these barriers were more modifiable.

Development and validation of an English version of the Coronary Artery Disease Education Questionnaire (CADE-Q)

Background: The Coronary Artery Disease Education Questionnaire (CADE‐Q) is a validated specific tool used to assess the knowledge and educate coronary patients in cardiac rehabilitation on aspects related to coronary artery disease (CAD). The aim of this study is to translate, cross‐culturally adapt and validate from Portuguese to English the Coronary Artery Disease Education Questionnaire (CADE‐Q). Methods: Two independent translations were performed by qualified translators. After back‐translation, both versions were reviewed by a committee of experts. A final English version was tested in a pilot study. For the psychometric validation, the tool was administered to 200 Canadian coronary patients enrolled in cardiac rehabilitation (CR). The internal consistency was assessed using Cronbachs alpha, the test–retest reliability using intraclass correlation coefficient (ICC), and the construct validity through factor analysis. Criterion validity of CADE-Q was assessed with regard to patients’ characteristics. Results: Eleven of 19 questions were modified and culturally adapted in the English version. Cronbachs alpha was 0.809 and ICC was 0.846. Factor analysis revealed five factors, all internally consistent and well defined by the items. Criterion validity was supported by significant differences in mean scores by family income (p = 0.02) and educational level (p < 0.001). Conclusion: The English version of the CADE-Q was demonstrated to have adequate reliability and validity, supporting its use in further studies.

Cardiorespiratory fitness and quality of life at different exercise intensities after myocardial infarction

FUNDAMENTO: Estudos que relacionam exercicios fisicos e saude tem contribuido para a compreensao da influencia de habitos sedentarios com a incidencia de doencas cardiovasculares. OBJETIVO: Comparar o efeito de diferentes intensidades de exercicio aerobio sobre a capacidade funcional (VO2 pico) e a qualidade de vida de pacientes pos-infarto agudo do miocardio. METODOS: 87 homens (57,7 anos, ± 6,1) participaram deste estudo prospectivo, com 12 semanas de treinamento fisico de alta intensidade (n=29), a 85% da frequencia cardiaca maxima, de intensidade moderada (n=29), a 75% da frequencia cardiaca maxima, ou no grupo controle (n=29), que recebeu acompanhamento clinico. O exercicio aerobio foi realizado cinco vezes por semana, 45 minutos por sessao, alem de exercicios de resistencia muscular e alongamentos. O VO2 pico foi mensurado com teste cardiopulmonar, e a qualidade de vida foi avaliada pelo questionario MacNew. RESULTADOS: A ANOVA two-way revelou aumento do VO2 pico significativo (p<0,05) no grupo de alta intensidade (29,9 ± 2,2 ml/kg.min para 41,6 ± 3,9 ml/kg.min) em relacao ao grupo de moderada intensidade (32,0 ± 5,3 ml/kg.min para 37,1 ± 3,9 ml/kg.min). Alem disso, ambos os grupos de exercicio aumentaram significativamente em relacao ao grupo controle (31,6 ± 3,9 para 29,2 ± 4,1). A qualidade de vida teve melhora significativa (p<0,05) no grupo de alta intensidade (5,66 para 6,80) e de moderada intensidade (5,38 para 6,72), mas nao no grupo controle (5,30 para 5,15) CONCLUSAO: Os exercicios de maior intensidade resultaram em maior aumento na capacidade funcional e na qualidade de vida em pacientes no pos-infarto do miocardio.

Perceptions of barriers to cardiac rehabilitation use in Brazil

Cardiovascular diseases (CVD) are the leading cause of mortality in middle-income countries, such as Brazil. However, given the diversity in health care systems in Brazil, access to proven services, such as cardiac rehabilitation (CR), varies widely. Purpose To describe and compare multilevel barriers to CR enrollment and participation in three Brazilian cohorts: (1) cardiac outpatients not attending CR (public or private system); (2) cardiac outpatients paying for CR; and (3) residents at high-risk of CVD with access to a free comprehensive exercise program but not making use of the program. Methods Brazilian residents from two cities were invited to participate – Florianopolis, an urban center; and Luzerna, a rural center. Respondents completed a survey including the Cardiac Rehabilitation Barriers Scale. Mann–Whitney U tests were used to compare barriers between cohorts cross-sectionally. Results Six hundred twenty-eight Brazilians consented to participate: 237 (37.7%) from Florianopolis, of which 139 (22.1%) participated in CR; and 391 (62.3%) from Luzerna. The mean total CR barriers for the sample were 1.66 ± 0.6 and differed significantly by cohort (P < 0.001). CR nonattendees from Florianopolis (eg, distance and not knowing about CR) and participants from Luzerna (eg, work and family responsibilities) reported significantly higher barriers than CR attendees from Florianopolis. Conclusion CR nonattendees reported significantly greater barriers than CR attendees. It is hoped that the provision of CR will increase, and that the development of the programs will be in a manner which mitigates the chief barriers identified herein.