Conditioning electrical stimulation promotes functional nerve regeneration.

Peripheral nerve regeneration following injury is often incomplete, resulting in significant personal and socioeconomic costs. Although a conditioning crush lesion prior to surgical nerve transection and repair greatly promotes nerve regeneration and functional recovery, feasibility and ethical considerations have hindered its clinical applicability. In a recent proof of principle study, we demonstrated that conditioning electrical stimulation (CES) had effects on early nerve regeneration, similar to that seen in conditioning crush lesions (CCL). To convincingly determine its clinical utility, establishing the effects of CES on target reinnervation and functional outcomes is of utmost importance. In this study, we found that CES improved nerve regeneration and reinnervation well beyond that of CCL. Specifically, compared to CCL, CES resulted in greater intraepidermal skin and NMJ reinnervation, and greater physiological and functional recovery including mechanosensation, compound muscle action potential on nerve conduction studies, normalization of gait pattern, and motor performance on the horizontal ladder test. These findings have direct clinical relevance as CES could be delivered at the bedside before scheduled nerve surgery.

Believability of messages about preventing breast cancer and heart disease through physical activity.

BACKGROUND: The purpose of this research was to examine the relationships of self-reported physical activity to involvement with messages that discuss the prevention of heart disease and breast cancer through physical activity, the explicit believability of the messages, and agreement (or disagreement) with specific statements about the messages or disease beliefs in general. METHODS: A within subjects' design was used. Participants (N = 96) read either a breast cancer or heart disease message first, then completed a corresponding task that measured agreement or disagreement and confidence in the agreement or disagreement that 1) physical activity 'reduces risk/does not reduce risk' of breast cancer or heart disease, 2) that breast cancer or heart disease is a 'real/not real risk for me', 3) that women who get breast cancer or heart disease are 'like/not like me', and 4) that women who get breast cancer or heart disease are 'to blame/not to blame'. This task was followed by a questionnaire measuring message involvement and explicit believability. They then read the other disease messages and completed the corresponding agreement and confidence task and questionnaire measures. Lastly, participants completed a questionnaire measuring physical activity related attitudes and intentions, and demographics. RESULTS: There was no difference in message involvement or explicit believability of breast cancer compared to heart disease messages. Active participants had a higher confidence in their agreement that physical activity is preventive of heart disease compared to breast cancer. Multinomial regression models showed that, in addition to physical activity related attitudes and intentions, agreement that physical activity was preventive of heart disease and that women with heart disease are 'like me' were predictors of being more active compared to inactive. In the breast cancer model only attitudes and intentions predicted physical activity group. CONCLUSIONS: Active women likely internalized messages about heart disease prevention through physical activity, making the prevention messages more readily available within memory, and active women may therefore process such information differently. The study of how health-related beliefs are created and are related to perceptions of prevention messages is a rich area of study that may contribute to more effective health promotion.

Resveratrol improves exercise performance and skeletal muscle oxidative capacity in heart failure.

We investigated whether treatment of mice with established pressure overload-induced heart failure (HF) with the naturally occurring polyphenol resveratrol could improve functional symptoms of clinical HF such as fatigue and exercise intolerance. C57Bl/6N mice were subjected to either sham or transverse aortic constriction surgery to induce HF. Three weeks postsurgery, a cohort of mice with established HF (%ejection fraction <45) was administered resveratrol (~450 mg·kg-1·day-1) or vehicle for 2 wk. Although the percent ejection fraction was similar between both groups of HF mice, those mice treated with resveratrol had increased total physical activity levels and exercise capacity. Resveratrol treatment was associated with altered gut microbiota composition, increased skeletal muscle insulin sensitivity, a switch toward greater whole body glucose utilization, and increased basal metabolic rates. Although muscle mass and strength were not different between groups, mice with HF had significant declines in basal and ADP-stimulated O2 consumption in isolated skeletal muscle fibers compared with sham mice, which was completely normalized by resveratrol treatment. Overall, resveratrol treatment of mice with established HF enhances exercise performance, which is associated with alterations in whole body and skeletal muscle energy metabolism. Thus, our preclinical data suggest that resveratrol supplementation may effectively improve fatigue and exercise intolerance in HF patients.NEW & NOTEWORTHY Resveratrol treatment of mice with heart failure leads to enhanced exercise performance that is associated with altered gut microbiota composition, increased whole body glucose utilization, and enhanced skeletal muscle metabolism and function. Together, these preclinical data suggest that resveratrol supplementation may effectively improve fatigue and exercise intolerance in heart failure via these mechanisms.

Intraoperative spinal cord monitoring using low intensity transcranial stimulation to remove post-activation depression of the H-reflex.

OBJECTIVE: To investigate whether low intensity transcranial electrical stimulation (TES) can be used to condition post-activation depression of the H-reflex and simultaneously monitor the integrity of spinal motor pathways during spinal deformity correction surgery. METHODS: In 20 pediatric patients undergoing corrective surgery for spinal deformity, post-activation depression of the medial gastrocnemius H-reflex was initiated by delivering two pulses 50-125ms apart, and the second H-reflex was conditioned by TES. RESULTS: Low intensity TES caused no visible shoulder or trunk movements during 19/20 procedures and the stimulation reduced post-activation depression of the H-reflex. The interaction was present in 20/20 patients and did not diminish throughout the surgical period. In one case, the conditioning effect was lost within minutes of the disappearance of the lower extremity motor evoked potentials. CONCLUSION: Post-activation depression was used to detect the arrival of a subthreshold motor evoked potential at the lower motor neuron. The interaction produced minimal movement within the surgical field and remained stable throughout the surgical period. SIGNIFICANCE: This is the first use of post-activation depression during intraoperative neurophysiological monitoring to directly assess the integrity of descending spinal motor pathways.

Improvements in skeletal muscle strength and cardiac function induced by resveratrol during exercise training contribute to enhanced exercise performance in rats.

Exercise training (ET) improves endurance capacity by increasing both skeletal muscle mitochondrial number and function, as well as contributing to favourable cardiac remodelling.Interestingly, some of the benefits of regular exercise can also be mimicked by the naturally occurring polyphenol, resveratrol (RESV). However, it is not known whether RESV enhances physiological adaptations to ET. To investigate this, male Wistar rats were randomly assigned to a control chow diet or a chow diet that contained RESV (4 g kg⁻¹ of diet) and subsequently subjected to a programme of progressive treadmill running for 12 weeks. ET-induced improvements in exercise performance were enhanced by 21% (P <0.001) by the addition of RESV to the diet. In soleus muscle, ET+RESV increased both the twitch (1.8-fold; P <0.05) and tetanic(1.2-fold; P <0.05) forces generated during isometric contraction, compared to ET alone. In vivo echocardiography demonstrated that ET+RESV also increased the resting left ventricular ejection fraction by 10% (P <0.05), and reduced left ventricular wall stress compared to ET alone.These functional changes were accompanied by increased cardiac fatty acid oxidation (1.2-fold;P <0.05) and favourable changes in cardiac gene expression and signal transduction pathways that optimized the utilization of fatty acids in ET+RESV compared to ET alone. Overall, our findings provide evidence that the capacity for fatty acid oxidation is augmented by the addition of RESV to the diet during ET, and that this may contribute to the improved physical performance of rats following ET.