Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice

Cunha TF, Moreira JB, Paixao NA, Campos JC, Monteiro AW, Bacurau AV, Bueno CR Jr., Ferreira JC, Brum PC. Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice. J Appl Physiol 112: 1839-1846, 2012. First published March 29, 2012; doi:10.1152/japplphysiol.00346.2011.-Aerobic exercise training (AET) is an important mechanical stimulus that modulates skeletal muscle protein turnover, leading to structural rearrangement. Since the ubiquitin-proteasome system (UPS) and calpain system are major proteolytic pathways involved in protein turnover, we aimed to investigate the effects of intensity-controlled AET on the skeletal muscle UPS and calpain system and their association to training-induced structural adaptations. Long-lasting effects of AET were studied in C57BL/6J mice after 2 or 8 wk of AET. Plantaris cross-sectional area (CSA) and capillarization were assessed by myosin ATPase staining. mRNA and protein expression levels of main components of the UPS and calpain system were evaluated in plantaris by real-time PCR and Western immunoblotting, respectively. No proteolytic system activation was observed after 2 wk of AET. Eight weeks of AET resulted in improved running capacity, plantaris capillarization, and CSA. Muscle RING finger-1 mRNA expression was increased in 8-wk-trained mice. Accordingly, elevated 26S proteasome activity was observed in the 8-wk-trained group, without accumulation of ubiquitinated or carbonylated proteins. In addition, calpain abundance was increased by 8 wk of AET, whereas no difference was observed in its endogenous inhibitor calpastatin. Taken together, our findings indicate that skeletal muscle enhancements, as evidenced by increased running capacity, plantaris capillarization, and CSA, occurred in spite of the upregulated UPS and calpain system, suggesting that overactivation of skeletal muscle proteolytic systems is not restricted to atrophying states. Our data provide evidence for the contribution of the UPS and calpain system to metabolic turnover of myofibrillar proteins and skeletal muscle adaptations to AET.

Comparative Analysis of the Complications of 5347 Endomyocardial Biopsies Applied to Patients After Heart Transplantation and With Cardiomyopathies: A Single-center Study

Introduction. Endomyocardial biopsy (EMB) plays an important role in allograft surveillance to screen an acute rejection episode after heart transplantation (HT), to diagnose an unknown cause of cardiomyopathies (CMP) or to reveal a cardiac tumor. However, the procedure is not risk free. Objective. The main objective of this research was to describe our experience with EMB during the last 33 years comparing surgical risk between FIT versus no-HT patients. Method. We analyzed retrospectively the data of 5347 EMBs performed from 1978 to 2011 (33 years). For surveillance of acute rejection episodes after HT we performed 3564 (66.7%), whereas 1777 (33.2%) for CMP diagnosis, and 6 (1.0%) for cardiac tumor identification. Results. The main complications due to EMB were divided into 2 groups to facilitate analysis: major complications associated with potential death risk, and minor complications. The variables that showed a significant difference in the HT group were as follows: tricuspid Injury (.0490) and coronary fistula (.0000). Among the no-HT cohort they were insufficient fragment (.0000), major complications (.0000) and total complications (.0000). Conclusions. EMB can be accomplished with a low risk of complications and high effectiveness to diagnose CMP and rejection after HT. However, the risk is great among patients with CMP due to their anatomic characteristics. Children also constitute a risk group for EMB due to their small size in addition to the heart disease. The risk of injury to the tricuspid valve was higher among the HT group.

Strength training with and without a vibration platform is capable to modulate heart rate variability?

The current research compared resting heart rate variability (VFC) before and after 10 weeks of strength training in groups that used and did not use a vibration platform. Seventeen healthy men were divided into conventional strength training (TF) or strength training using a vibration platform with a frequency of 30 Hz (TF+V30) training groups. One repetition maximum load (1-RM) on half squat exercise and VFC measurements were determined pre- and post-training program. Both groups had improved 1-RM load after the program (15.1% in TF group and 16.4% in TF+V30 group), although this increase was changed in the same extent for the two groups and there was no difference in 1-RM load between groups pre- and post-training program. No significant difference was observed in resting VFC measurements between groups pre and post-training program, however the magnitude of the effect size was moderated (ES = 0.50-0.80) for some variables (R-R interval, standard deviation of all R-R interval - SDNN, RMSSD, log-transformed of low frequency - InLF, and log-transformed of high frequency - InHF) in TF+V30 group. It was concluded that 10 weeks of strength training program with or without the vibration platform provided similar increase in 1-RM load in both groups, and although some evidences in this study indicate that vibration can increase vagal activity analyzed by ES, in neither groups the strength training was able to change VFC significantly.