High Cardiorespiratory Fitness Protects against Molecular Impairments of Metabolism, Heart, and Brain with Higher Efficacy in Obesity-Induced Premature Aging

BACKGRUOUND

High cardiorespiratory fitness (CRF) protects against age-related diseases. However, the mechanisms mediating the protective effect of high intrinsic CRF against metabolic, cardiac, and brain impairments in non-obese versus obese conditions remain incompletely understood. We aimed to identify the mechanisms through which high intrinsic CRF protects against metabolic, cardiac, and brain impairments in non-obese versus obese untrained rats.

METHODS

Seven-week-old male Wistar rats were divided into two groups (n=8 per group) to receive either a normal diet or a highfat diet (HFD). At weeks 12 and 28, CRF, carbohydrate and fatty acid oxidation, cardiac function, and metabolic parameters were evaluated. At week 28, behavior tests were performed. At the end of week 28, rats were euthanized to collect heart and brain samples for molecular studies.

RESULTS

The obese rats exhibited higher values for aging-related parameters than the non-obese rats, indicating that they experienced obesity-induced premature aging. High baseline CRF levels were positively correlated with several favorable metabolic, cardiac, and brain parameters at follow-up. Specifically, the protective effects of high CRF against metabolic, cardiac, and brain impairments were mediated by the modulation of body weight and composition, the lipid profile, substrate oxidation, mitochondrial function, insulin signaling, autophagy, apoptosis, inflammation, oxidative stress, cardiac function, neurogenesis, blood-brain barrier, synaptic function, accumulation of Alzheimer's disease-related proteins, and cognition. Interestingly, this effect was more obvious in HFD-fed rats.

CONCLUSION

The protective effect of high CRF is mediated by the modulation of several mechanisms. These effects exhibit greater efficacy under conditions of obesity-induced premature aging.

Peak oxygen uptake and metabolic equivalents explained by six-minute walk test: A prospective observational study in predicting heart failure patient readmission

Background

Methods

Results

Conclusions

•

Functional capacity contributes to reducing cardiovascular events and re-hospitalization of patients with heart failure.

•

Conducting a 6-min walk test before patient discharge can help identify a patients' risk for readmission.

•

VO2max and METs can be utilized to create a comprehensive treatment flow for heart failure patients to prevent readmission.

Obesity and Hypertension in Association with Diastolic Dysfunction Could Reduce Exercise Capacity

BACKGROUND AND OBJECTIVES

Empirical evidence is lacking on the cumulative disease burden of obesity and hypertension and its impact on cardiac function and exercise capacity. The purpose of this study was to determine whether the presence of obesity and hypertension together was associated with cardiac dysfunction and exercise capacity.

SUBJECTS AND METHODS

Using a retrospective study design, medical records were reviewed for echocardiographic and treadmill exercise stress test data. Subjects were grouped according to four categories: normal control, obese, hypertensive, or obese and hypertensive.

RESULTS

Obese, hypertensive persons showed significantly lower Ea and E/A ratio and greater E/Ea ratio, deceleration time, left ventricular (LV) mass, and LV mass index compared to their counter parts (normal control, obese and/or hypertensive) (all p<0.05), after controlling for age and sex. After controlling for age and sex, significant differences in exercise capacity indices were found, with the obese group having shorter exercise time, lower metabolic equivalents, and lower maximal oxygen uptake than the normal control, hypertensive, or both groups (all p<0.05). The hypertensive or obese and hypertensive group had greater maximal blood pressure compared with the normal control group (all p<0.001). Obese and hypertensive persons were approximately three times more likely to have diastolic dysfunction (odd ratio=2.96, p=0.001), when compared to the reference group (normotensive, non-obese, or hypertensive only persons).

CONCLUSION

Diastolic dysfunction was associated with obesity and/or hypertension. The cumulative risk of obesity and hypertension and their impact on diastolic dysfunction which could be modifiable could reduce exercise capacity.

The safety and efficacy of early-initiation exercise training after acute venous thromboembolism: a randomized clinical trial

BACKGROUND

Exercise training after myocardial infarction is the standard of care within a cardiac rehabilitation setting. However, there is scant evidence regarding the safety and efficacy of early exercise training following a venous thromboembolism (VTE).

METHODS

Eligible consenting participants were randomly allocated, on an individual basis, to either a 3-month exercise and behavioral weight loss intervention group or a control group. The primary clinical outcomes were change in health behavior (body weight and physical activity) and objectively measured fitness (Vo2peak ).

RESULTS

From 2013 to 2014, 239 patients presented to a community-based specialty clinic after an acute VTE; 43 (18%) of these met the eligibility criteria for inclusion in the study. Of these, 19 (44%) consented to participate (nine in the intervention group; 10 in the control group). There were no adverse events in either group over a 3-month period. The mean difference in body weight between the intervention and control groups was - 4.6 kg (95% confidence interval [CI] - 11.4 to 2.2) in favor of the intervention. The mean difference in duration of physical activity from baseline to 3 months between the intervention and control groups was 133 min (95% CI 7-248) in favor of the intervention. There was a significant change in fitness over a 3-month period for the intervention group (baseline Vo2peak , 26.1 ± 5.4 mL O2 kg(-1)  min(-1) ; postintervention Vo2peak , 29.8 ± 5.4 mL O2 kg(-1)  min(-1) ).

CONCLUSION

Early initiation of exercise training resulted in improvements in physical activity and fitness, and did not result in adverse events while individuals were receiving therapeutic anticoagulation. These are the first data on initiation of an exercise training and behavioral weight loss program in the early post-VTE setting.

Successful weight reduction improves left ventricular diastolic function and physical performance in severe obesity

Obesity and the metabolic syndrome (MetS) are risk factors for left ventricular diastolic dysfunction (LVDD). However, little is known about the impact of successful weight reduction (WR) on diastolic function and physical performance.Obese subjects (øBMI 40.2 ± 8.6 kg/m(2)) underwent a 1-year WR program comprising diet and lifestyle components. Echocardiography and exercise capacity (6-minute walk) were performed at baseline and after 1 year. The distribution of weight reduction was split at the sample median and subjects were dichotomized in "successful WR" (% WR ≥ median, corresponding to a weight loss of 8%) and "failed-WR" (% WR < median).From a total of 188 obese subjects, 71 had LVDD at baseline. Obese patients with successful WR improved their MetS alterations, including fasting glucose, insulin, lipids, adipokines, blood pressure levels, and epicardial fat thickness. The same was not true for obesity with failed WR. Subjects with successful WR demonstrated significant improvement in echocardiographic LVDD parameters (median [interquartile range]): Δe' (2,5 [-1.0, 4.7], P < 0.01), Δe'/a' (0.34 [0.07, 079], P < 0.01), ΔE/e' (-1.14 [-2.72, -0.54], P < 0.05), ΔE/A (0.08 [-0.04, 0.26], P < 0.05), ΔArd-Ad (-28 [-54, -4], P < 0.01), and 6-minute walk distance (65 [19, 135], P < 0.01). Improvement of ≥ 2 LVDD criteria was accomplished in 30% of subjects with WR versus 10% without (P = 0.009). Using multivariable regression analysis, reduction of epicardial fat thickness was particularly predictive for the improvement of diastolic function.In summary, in severe obesity, successful long-term WR was associated with improved LV diastolic function and exercise capacity.

Effect of Walking Exercise on Changes in Cardiorespiratory Fitness, Metabolic Syndrome Markers, and High-molecular-weight Adiponectin in Obese Middle-aged Women

[Purpose] The purpose of this study was to assess the effect of a 24-week exercise intervention on cardiorespiratory fitness, metabolic syndrome markers, and high-molecular-weight (HMW) adiponectin among obese middle-aged women. [Subjects] The subjects were 14 obese middle-aged women. [Methods] The exercise program involved walking at 50–60% of the maximum oxygen consumption, 3 times a week, for 24 weeks. Body composition analysis, blood pressure measurements, and blood analysis were performed before the exercise program and at weeks 6, 12, 18, and 24. [Results] The results showed that after 24 weeks in the exercise program, the obesity indices and metabolic risk factors, namely, weight, body fat, body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, and triglycerides decreased significantly, whereas HDLC, a metabolic improvement factor, increased significantly. Additionally, VO_2max increased significantly, together with the level of total and HMW adiponectins. Correlation analysis of the changes in measured variables (∆ score) during resulting from the 24-week exercise program showed that body fat had a significant negative correlation and VO_2max had a significant positive correlation with HMW adiponectin. [Conclusion] Among obese middle-aged women, regular exercise increases cardiorespiratory fitness and HMW adiponectin expression and therefore can be effective in the prevention and treatment of obesity and metabolic syndrome.

Regulation of pyruvate metabolism and human disease

Pyruvate is a keystone molecule critical for numerous aspects of eukaryotic and human metabolism. Pyruvate is the end-product of glycolysis, is derived from additional sources in the cellular cytoplasm, and is ultimately destined for transport into mitochondria as a master fuel input undergirding citric acid cycle carbon flux. In mitochondria, pyruvate drives ATP production by oxidative phosphorylation and multiple biosynthetic pathways intersecting the citric acid cycle. Mitochondrial pyruvate metabolism is regulated by many enzymes, including the recently discovered mitochondria pyruvate carrier, pyruvate dehydrogenase, and pyruvate carboxylase, to modulate overall pyruvate carbon flux. Mutations in any of the genes encoding for proteins regulating pyruvate metabolism may lead to disease. Numerous cases have been described. Aberrant pyruvate metabolism plays an especially prominent role in cancer, heart failure, and neurodegeneration. Because most major diseases involve aberrant metabolism, understanding and exploiting pyruvate carbon flux may yield novel treatments that enhance human health.

Effect of exercise training on diastolic function in metabolic syndrome

It has been reported that metabolic syndrome (MetS) impairs left ventricular (LV) diastolic function. The objective of this study was to determine whether exercise training can improve LV diastolic function in individuals with MetS. Twenty-eight individuals with MetS (9 males, aged 60 ± 5 years) underwent a 1-year combined endurance and resistance exercise training program; maximal aerobic capacity (V̇O2max), blood pressure, blood markers, and LV diastolic function were measured at weeks 0, 12, 24, and 52 throughout the training. Pulsed wave Doppler echocardiography across the mitral valve was used to assess peak early flow velocity (E) and peak atrial flow velocity (A) to determine the E/A ratio. Individuals with MetS had a reversed E/A ratio, suggesting impaired LV relaxation, the first stage of LV diastolic dysfunction. Exercise training reduced systolic blood pressure (SBP) (129 ± 14 to 120 ± 12 mm Hg; p < 0.01) and increased V̇O2max (29.2 ± 6.3 to 33.4 ± 6.5 mL·kg−1·min−1; p < 0.01) and high-density lipoprotein cholesterol (1.04 ± 0.21 to 1.12 ± 0.25 mmol·L−1; p = 0.02), but did not improve LV diastolic function. Individuals with an E/A ratio <1 at the start of training had a tendency toward an increased E/A ratio (p = 0.12) accompanied by significant decreases in SBP and increases in V̇O2max with exercise training. Combined resistance and aerobic exercise training improved cardiometabolic health but did not improve the impaired LV diastolic function of individuals with MetS.

Long-term impact of multifactorial treatment on new-onset diabetes and related cardiovascular events in metabolic syndrome: a post hoc ATTEMPT analysis

This post hoc analysis of the Assessing The Treatment Effect in Metabolic Syndrome Without Perceptible diabeTes (ATTEMPT) study assesses the 3½ year incidence of new-onset diabetes (NOD) and related cardiovascular disease (CVD) events in patients with metabolic syndrome (MetS), after multifactorial (lifestyle and drug, including atorvastatin) intervention. Patients were randomized to group A (low-density lipoprotein cholesterol [LDL-C] target < 100 mg/dL) and group B (< 130 mg/dL). The incidence of NOD during the 42-month follow-up was very low, 0.83 to 1.00/100 patient-years in patients with MetS and MetS with impaired fasting glucose, respectively. Older age, increased waist circumference, and persistent MetS were determinants of NOD. One CVD nonfatal event occurred in the 28 patients with NOD. Our findings suggest that treating the characteristics of MetS is achievable and beneficial. New-onset diabetes incidence and CVD events were negligible and not different from what is expected in the general population.