Cardioprotection conferred by exercise training is blunted by blockade of the opioid system

OBJECTIVES: To investigate the effect of opioid receptor blockade on the myocardial protection conferred by chronic exercise and to compare exercise training with different strategies of myocardial protection (opioid infusion and brief periods of ischemia-reperfusion) preceding irreversible left anterior descending coronary ligation. INTRODUCTION: The acute cardioprotective effects of exercise training are at least partly mediated through opioid receptor-dependent mechanisms in ischemia-reperfusion models. METHODS: Male Wistar rats (n = 76) were randomly assigned to 7 groups: (1) control; (2) exercise training; (3) morphine; (4) intermittent ischemia-reperfusion (three alternating periods of left anterior descending coronary occlusion and reperfusion); (5) exercise training+morphine; (6) naloxone (a non-selective opioid receptor blocker) plus morphine; (7) naloxone before each exercise-training session. Myocardial infarction was established in all groups by left anterior descending coronary ligation. Exercise training was performed on a treadmill for 60 minutes, 5 times/week, for 12 weeks, at 60% peak oxygen (peak VO2). Infarct size was histologically evaluated. RESULTS: Exercise training significantly increased exercise capacity and &#916;VO2 (VO2 peak - VO2 rest) (p<0.01 vs. sedentary groups). Compared with control, all treatment groups except morphine plus naloxone and exercise training plus naloxone showed a smaller infarcted area (p<0.05). No additional decrease in infarct size occurred in the exercise training plus morphine group. No difference in myocardial capillary density (p = 0.88) was observed in any group. CONCLUSIONS: Exercise training, morphine, exercise training plus morphine and ischemia-reperfusion groups had a smaller infarcted area than the control group. The effect of chronic exercise training in decreasing infarct size seems to occur, at least in part, through the opioid receptor stimulus and not by increasing myocardial perfusio

Resting spontaneous baroreflex sensitivity and cardiac autonomic control in anabolic androgenic steroid users

OBJECTIVES: Misuse of anabolic androgenic steroids in athletes is a strategy used to enhance strength and skeletal muscle hypertrophy. However, its abuse leads to an imbalance in muscle sympathetic nerve activity, increased vascular resistance, and increased blood pressure. However, the mechanisms underlying these alterations are still unknown. Therefore, we tested whether anabolic androgenic steroids could impair resting baroreflex sensitivity and cardiac sympathovagal control. In addition, we evaluate pulse wave velocity to ascertain the arterial stiffness of large vessels. METHODS: Fourteen male anabolic androgenic steroid users and 12 nonusers were studied. Heart rate, blood pressure, and respiratory rate were recorded. Baroreflex sensitivity was estimated by the sequence method, and cardiac autonomic control by analysis of the R-R interval. Pulse wave velocity was measured using a noninvasive automatic device. RESULTS: Mean spontaneous baroreflex sensitivity, baroreflex sensitivity to activation of the baroreceptors, and baroreflex sensitivity to deactivation of the baroreceptors were significantly lower in users than in nonusers. In the spectral analysis of heart rate variability, high frequency activity was lower, while low frequency activity was higher in users than in nonusers. Moreover, the sympathovagal balance was higher in users. Users showed higher pulse wave velocity than nonusers showing arterial stiffness of large vessels. Single linear regression analysis showed significant correlations between mean blood pressure and baroreflex sensitivity and pulse wave velocity. CONCLUSIONS: Our results provide evidence for lower baroreflex sensitivity and sympathovagal imbalance in anabolic androgenic steroid users. Moreover, anabolic androgenic steroid users showed arterial stiffness. Together, these alterations might be the mechanisms triggering the increased blood pressure in this population

Cardiopulmonary exercise test in patients with refractory angina: functional and ischemic evaluation

Objectives: Refractory angina (RA) is a chronic condition clinically characterized by low effort tolerance; therefore, physical stress testing is not usually requested for these patients. Cardiopulmonary exercise testing (CPET) is considered a gold standard examination for functional capacity evaluation, even in submaximal tests, and it has gained great prominence in detecting ischemia. The authors aimed to determine cardiorespiratory capacity by using the oxygen consumption efficiency slope (OUES) in patients with refractory angina. The authors also studied the O2&nbsp;pulse response by CPET and the association of ischemic changes with contractile modifications by exercise stress echocardiography (ESE). Methods: Thirty-one patients of both sexes, aged&nbsp;45&nbsp;to&nbsp;75&nbsp;years, with symptomatic (Canadian Cardiovascular Society class&nbsp;II to&nbsp;IV) angina who underwent CPET on a treadmill and exercise stress echocardiography on a lower limb cycle ergometer were studied. ClinicalTrials.gov:&nbsp;NCT03218891. Results: The patients had low cardiorespiratory capacity (OUES of&nbsp;1.74 ± 0.4&nbsp;L/min; 63.9±14.7% of predicted), and 77% of patients had a flattening or drop in O2&nbsp;pulse response. There was a direct association between Heart Rate (HR) at the onset of myocardial ischemia detected by ESE and HR at the onset of flattening or drop in oxygen pulse response detected by CPET (R&nbsp;=&nbsp;0.48; p&nbsp;=&nbsp;0.019). Conclusion: Patients with refractory angina demonstrate low cardiorespiratory capacity. CPET shows good sensitivity for detecting abnormal cardiovascular response in these patients with a significant relationship between flattening O2&nbsp;pulse response during CEPT and contractile alterations detected by exercise stress echocardiography

Augmented muscle vasodilatory responses in obese children with Glu27 beta(2)-adrenoceptor polymorphism

This study examined forearm vasodilatation during mental challenge and exercise in 72 obese children (OC; age = 10 +/- 0.1 years) homozygous with polymorphism in the allele 27 of the beta(2)-adrenoceptors: Gln27 (n = 61) and Glu27 (n = 11). Forearm blood flow was recorded during 3 min of each using the Stroop color-word test (MS) and handgrip isometric exercise. Baseline hemodynamic and vascular measurements were similar. During the MS, peak forearm vascular conductance was significantly greater in group Glu27 (Delta = 0.35 +/- 0.4 vs. 0.12 +/- 0.1 units, respectively, p = .042). Similar results were found during exercise (Delta = 0.64 +/- 0.1 vs. 0.13 +/- 0.1 units, respectively, p = .035). Glu27 OC increased muscle vasodilatory responsiveness upon the MS and exercise

Arousals are frequent and associated with exacerbated blood pressure response in patients with primary hypertension

Background\ud Spontaneous arousals are relatively common during sleep, and induce\ud hemodynamic responses. We sought to investigate the frequency and\ud magnitude of blood pressure (BP) increases triggered by spontaneous\ud arousals in patients with primary hypertension.\ud Methods\ud We conducted a study in which we divided 18 nonobese, sedentary\ud adults without sleep-disordered breathing into two groups, consisting\ud of: (i) hypertensive (HT, n = 8) patients; and (ii) normotensive (NT, n = 10)\ud controls. The groups were matched for age and body mass index. All\ud subjects underwent full polysomnography with simultaneous monitoring\ud of heart rate (HR) and beat-by-beat BP. Each subject’s BP and HR\ud were analyzed immediately before BP peaks triggered by spontaneous\ud arousals during stage 2 of nonrapid eye movement sleep.\ud Results\ud The total sleep time, sleep efficiency, and sleep structure in the two\ud study groups were similar. In contrast, the number of arousals was\ud significantly higher in the HT than in the NT group, at 25 ± 5 vs. 12 ± 3\ud events/h, respectively (P < 0.05). The HR of the HT and NT groups was\ud similar before arousal (65 ± 3 bpm vs. 67 ± 3 bpm, respectively, P < 0.01)\ud and increased significantly and similarly in the two groups upon arousal\ud (to 79 ± 6 bpm vs. 74 ± 4 bpm, respectively, P < 0.01). Systolic and diastolic\ud BPs were significantly higher throughout sleep in the HT than\ud in the NT group. During spontaneous arousals, BP increased in both\ud groups (P < 0.05). However, the magnitude of the increase in systolic BP\ud was significantly greater in the HT than in the NT group (22 ± 3 mm Hg\ud vs. 15 ± 3 mm Hg, P < 0.05).\ud Conclusions\ud Patients with hypertension who do not have sleep-disordered breathing\ud have an increased cardiovascular burden during sleep, which may\ud be due to the greater number of arousals and exacerbated systolic BP\ud response that they experience during sleep. These novel findings may\ud have cardiovascular implications in patients with hypertensionFAPESP 2010/18183–6Conselho Nacional de Pesquisa (CNPq) 301867/2010-0Fundação Zerbin

The Impact of Obstructive Sleep Apnea on Metabolic and Inflammatory Markers in Consecutive Patients with Metabolic Syndrome

Background: Obstructive Sleep Apnea (OSA) is tightly linked to some components of Metabolic Syndrome (MetS). However, most of the evidence evaluated individual components of the MetS or patients with a diagnosis of OSA that were referred for sleep studies due to sleep complaints. Therefore, it is not clear whether OSA exacerbates the metabolic abnormalities in a representative sample of patients with MetS. Methodology/Principal Findings: We studied 152 consecutive patients (age 48 +/- 9 years, body mass index 32.3 +/- 3.4 Kg/m(2)) newly diagnosed with MetS (Adult Treatment Panel III). All participants underwent standard polysomnography irrespective of sleep complaints, and laboratory measurements (glucose, lipid profile, uric acid and C-reactive protein). The prevalence of OSA (apnea-hypopnea index >= 15 events per hour of sleep) was 60.5%. Patients with OSA exhibited significantly higher levels of blood pressure, glucose, triglycerides, cholesterol, LDL, cholesterol/HDL ratio, triglycerides/HDL ratio, uric acid and C-reactive protein than patients without OSA. OSA was independently associated with 2 MetS criteria: triglycerides: OR: 3.26 (1.47-7.21) and glucose: OR: 2.31 (1.12-4.80). OSA was also independently associated with increased cholesterol/HDL ratio: OR: 2.38 (1.08-5.24), uric acid: OR: 4.19 (1.70-10.35) and C-reactive protein: OR: 6.10 (2.64-14.11). Indices of sleep apnea severity, apnea-hypopnea index and minimum oxygen saturation, were independently associated with increased levels of triglycerides, glucose as well as cholesterol/HDL ratio, uric acid and C-reactive protein. Excessive daytime sleepiness had no effect on the metabolic and inflammatory parameters. Conclusions/Significance: Unrecognized OSA is common in consecutive patients with MetS. OSA may contribute to metabolic dysregulation and systemic inflammation in patients with MetS, regardless of symptoms of daytime sleepiness.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[200032/2009-7]Fundacao Zerbini, BrazilNational Sleep Foundation/American Lung Association Pickwick[SF-78568 N]National Institutes of Health (NIH)[HL07534]National Institutes of Health (NIH)[R01 HL80105]National Institutes of Health (NIH)[5P50HL084945]American Heart Association[0765293U](BSF) United States Israel Binational Science Foundation[2005265

A Survey of mid and large bodied mammals in Núcleo Caraguatatuba, Serra do Mar State Park, Brazil

Nós aplicamos técnicas de amostragem complementares para obter uma lista de espécies de mamíferos de médio e grande porte no Núcleo Caraguatatuba, Parque Estadual da Serra do Mar, Brasil. As amostragens de campo realizaram-se nos meses de Maio e Setembro de 2011. Utilizou-se, censo ao longo de transectos (212,4 km), armadilhas fotográficas (223,2 armadilhas-dias) e armadilhas de pegadas (478 armadilhas-dias). Foram obtidos registros de 18 espécies, pertencentes a 14 famílias e oito ordens. Nós registramos a presença de sete espécies consideradas ameaçadas no Estado de São Paulo, incluindo primatas (Brachyteles arachnoides), Artiodactyla (Mazama americana e Tayassu pecari), Carnivora (Leopardus pardalis, Leopardus tigrinus e Puma concolor) e Perissodactyla (Tapirus terrestris). Com base em numa extrapolação da riqueza de espécies (First order jackknife) nós prevemos que existem entre 19 e 32 espécies de mamíferos de médio e grande porte no Núcleo. Nosso Mammal Priority Index classificou o Núcleo Caraguatatuba como uma área de importância média para a conservação de mamíferos de médio e grande porte na Mata Atlântica. Combinado com o número e a diversidade de espécies registradas, nossos resultados demonstram que este Núcleo é uma área importante para a conservação de mamíferos no Estado.We applied complementary survey techniques to obtain a baseline species list of mid and large bodied mammals in Núcleo Caraguatatuba, Serra do Mar State park, Brazil. Between May and September 2011 we surveyed the community of mid and large bodied mammals using diurnal line transect census (212.4 km), camera-traps (223.2 camera-trap days) and track-stations (478 track-station days). A total of 18 species were recorded from 14 families in eight orders. We recorded the presence of seven species considered threatened in the State of São Paulo, including Primates (Brachyteles arachnoides), Artiodactyla (Mazama cf. americana and Tayassu pecari), Carnivora (Leopardus pardalis, Leopardus tigrinus and Puma concolor) and Perissodactyla (Tapirus terrestris). Based on extrapolated (First order jackknife) species richness estimates we predict that there are between 19 and 32 species of mid and large bodied mammals in the Núcleo. Our revised Mammal Priority Index ranked Núcleo Caraguatatuba as being of medium overall importance for the conservation of mid and large bodied mammals in the Atlantic Forest. Combined with the number and diversity of species recorded, our results demonstrate that this Núcleo is an important area for mammal conservation