The neurostructural and neurocognitive effects of physical activity: A potential benefit to promote eating disorder recovery

Accumulating evidence suggests that supervised and adapted physical activity provides cognitive benefits for individuals with eating disorders (EDs). The mechanisms underlying the benefits of physical activity are poorly understood. Addressing this knowledge gap may inform the appropriate integration of structured physical activity into eating disorders treatment and recovery. We draw attention to recent findings in the study of the impact of physical activity on the brain, and we describe the neurostructural and neurocognitive changes associated with physical activity observed in various clinical and nonclinical populations. Considering the identified impairment in brain volume- and/or neurocognitive function in various EDs, we propose that positive effects of physical activity may play a meaningful role in successful ED treatment. Accordingly, we outline research steps for closing the knowledge gap on how physical activity may aid in ED recovery, and emphasize the need to combine measures of cognitive and behavioral responses to physical activity, with technology capable of measuring changes in brain structure and/or function.     

Crosstalk between adipokines and myokines in fat browning

Skeletal muscle is the largest organ determining whole‐body insulin sensitivity and metabolic homoeostasis. Adaptive changes of skeletal muscle in response to physical activity include adjustments in the production and secretion of muscle‐derived bioactive factors, known as myokines, such as myostatin, IL‐4, IL‐6, IL‐7 and IL‐15, myonectin, follistatin‐like 1 or leukaemia inhibitory factor. These myokines not only act locally in the muscle in an autocrine/paracrine manner, but also are released to the bloodstream as endocrine factors to regulate physiological processes in other tissues. Irisin, derived from the cleavage of FNDC5 protein, constitutes a myokine that induces myogenesis and fat browning (switch of white adipocytes to brown fat‐like cells) together with a concomitant increase in energy expenditure. Besides being a target for irisin actions, the adipose tissue also constitutes a production site of FNDC5. Interestingly, irisin secretion from subcutaneous and visceral fat depots is decreased by long‐term exercise training and fasting, suggesting a discordant regulation of FNDC5/irisin in skeletal muscle and adipose tissue. Accordingly, our group has recently reported that the adipokine leptin differentially regulates FNDC5/irisin expression in skeletal muscle and fat, confirming the crosstalk between both tissues. Moreover, irisin secretion and function are regulated by other myokines, such as follistatin or myostatin, as well as by other adipokines, including fibroblast growth factor 21 and leptin. Taken together, myokines have emerged as novel molecular mediators of fat browning and their activity can be modulated by adipokines, confirming the crosstalk between skeletal muscle and adipose tissue to regulate thermogenesis and energy expenditure.     

代谢相关性肌细胞因子的研究进展

 肌细胞因子(myokines)是由肌细胞合成和释放,发挥自分泌、旁分泌或内分泌功能的细胞因子及多肽类物质。肌细胞因子可作用于骨骼肌自身及脂肪、肝脏、胰腺、骨骼等多种组织器官参与机体物质和能量代谢并影响各组织器官的结构和功能,从而在维持机体的生物学稳态中发挥重要作用。目前已发现的肌细胞因子有数百种,其中鸢尾素(irisin)、肌联素(myonectin)、肌肉抑制素(myostatin)、脑源性神经营养因子(brain-derived neurotrophic factor, BDNF)等对机体糖脂及能量代谢起到重要作用。本文主要阐述上述几种代谢相关性肌细胞因子的合成和分泌、生理作用、作用机制及潜在临床应用。     

Effect of an acute exercise bout on immediate post‐exercise irisin concentration in adults: A meta‐analysis

Irisin is a recently discovered myokine that increases adipocyte metabolism, induces further “browning” of white adipose tissue, and enhances glucose metabolism. No study has ever determined how an acute bout of exercise impacts immediate post‐exercise irisin concentration using a meta‐analytic approach. The purpose of this study is to determine the impact of an acute bout of exercise on the magnitude of post‐exercise irisin concentration in adults using meta‐analytic procedures. Searches were performed on PubMed, EMBASE, CINAHL, PEDro, SCOPUS, and SPORTDiscus databases. Effect summaries were obtained using random‐effects models. Random‐effects single and multiple meta‐regressions were performed to determine relationships between, and potential confounding effects of, variables of interest. Ten articles were retained for the final meta‐analysis, producing 21 study estimates. An acute bout of exercise was accompanied by a post‐exercise average increase in irisin concentration of 15.0 (95% CI: 10.8%‐19.3%). There was no significant relationship between post‐exercise irisin concentration and age, intensity of aerobic exercise, or type of exercise training session (resistance vs aerobic training). Fitness level and body mass index were identified as significant predictive variables for post‐exercise irisin concentration. However, a multiple meta‐regression model identified fitness level as the single best predictor, with being fit (21.1%±2.2%) associated with a nearly twofold increase in post‐exercise irisin concentration, compared with being unfit (11.8%±2.1%). Immediately following an acute bout of exercise, irisin concentration increases substantially in adults, with fitness level as an important modifier for the effect.     

COVID-19: sitting is the new smoking; the role of exercise in augmenting the immune system among the elderly

IntroductionLike smoking, sedentary lifestyle is an issue of great concern because of its deleterious health challenges and implications. Given the global spread of the new coronavirus (COVID-19), social isolation regulations and laws have been implemented in many countries to contain the spread of the virus and this has caused a drastic shift from the usual physically demanding life to a sedentary lifestyle characterized by significantly reduced physical activities and prolong sitting.Methods/Data SourceHuman and nonhuman primate literature was examined to compare experimental and clinical modulation of inflammatory cytokines by exercised-induced myokines.Data synthesisExperimental and clinical evidence was used to examine whether exercised-induced myokines can prime the immune system of the elderly population during the COVID-19 pandemic.ConclusionThe immune system changes with advancement in age which increases the likelihood of infectious disease morbidity and mortality in older adults. Several epidemiological studies have also shown that physical inactivity among geriatric population impacts negatively on the immune system. Evidences on the importance of exercise in priming the immune system of elderly individuals could be an effective therapeutic strategy in combating the virus as it may well be a case of “let those with the best immune system win”.     

Nordic Walking Rather Than High Intensity Interval Training Reduced Myostatin Concentration More Effectively in Elderly Subjects and the Range of This Drop Was Modified by Metabolites of Vitamin D

The COVID-19 pandemic and subsequent self-isolation exacerbated the problem of insufficient amounts of physical activity and its consequences. At the same time, this revealed the advantage of vitamin D. Thus, there was a need to verify the effects of those forms of training that can be performed independently. In this study, we examined the effects of Nordic walking (NW) and high intensity interval training (HIIT) with regard to the impact of the metabolite vitamin D. We assigned 32 overweight adults (age = 61 ± 12 years) to one of two training groups: NW = 18 and HIIT = 14. Body composition assessment and blood sample collection were conducted before starting the training programs and a day after their completion. NW training induced a significant decrease in myostatin (p = 0.05) concentration; however, the range was dependent on the baseline concentrations of vitamin D metabolites. This drop was accompanied by a significant negative correlation with the decorin concentration. Unexpectedly, NW caused a decrement in both forms of osteocalcin: undercarboxylated (Glu-OC) and carboxylated-type (Gla-OC). The scope of Glu-OC changes was dependent on a baseline concentration of 25(OH)D₂ (r = −0.60, p = 0.01). In contrast, the HIIT protocol did not induce any changes. Overall results revealed that NW diminished the myostatin concentration and that this effect is more pronounced among adults with a sufficient concentration of vitamin D metabolites.     

Impact of physical activity on inflammation: effects on cardiovascular disease risk and other inflammatory conditions

Since the 19^th century, many studies have enlightened the role of inflammation in atherosclerosis, changing our perception of “vessel plaque due to oxidized lipoproteins”, similar to a “rusted pipe”, towards a disease with involvement of many cell types and cytokines with more complex mechanisms. Although “physical activity” and “physical exercise” are two terms with some differences in meaning, compared to sedentary lifestyle, active people have lower cardiovascular risk and lower inflammatory markers. Activities of skeletal muscle reveal “myokines” which have roles in both the immune system and adipose tissue metabolism. In vitro and ex-vivo studies have shown beneficial effects of exercise on inflammation markers. Meanwhile in clinical studies, some conflicting results suggested that type of activity, exercise duration, body composition, gender, race and age may modulate anti-inflammatory effects of physical exercise. Medical data on patients with inflammatory diseases have shown beneficial effects of exercise on disease activity scores, patient well-being and inflammatory markers. Although the most beneficial type of activity and the most relevant patient group for anti-inflammatory benefits are still not clear, studies in elderly and adult people generally support anti-inflammatory effects of physical activity and moderate exercise could be advised to patients with cardiovascular risk such as patients with metabolic syndrome.     

Potential role of skeletal muscle glucose metabolism on the regulation of insulin secretion

Pancreatic beta cells sense glucose flux and release as much insulin as required in order to maintain glycaemia within a narrow range. Insulin secretion is regulated by many factors including glucose, incretins, and sympathetic and parasympathetic tones among other physiological factors. To identify the mechanisms linking obesity‐related insulin resistance with impaired insulin secretion represents a central challenge. Recently, it has been argued that a crosstalk between skeletal muscle and the pancreas may regulate insulin secretion. Considering that skeletal muscle is the largest organ in non‐obese subjects and a major site of insulin‐ and exercise‐stimulated glucose disposal, it appears plausible that muscle might interact with the pancreas and modulate insulin secretion for appropriate peripheral intracellular glucose utilization. There is growing evidence that muscle can secrete so‐called myokines that can have auto/para/endocrine actions. Although it is unclear in which direction they act, interleukin‐6 seems to be a possible muscle‐derived candidate protein mediating such inter‐organ communication. We herein review some of the putative skeletal muscle‐derived factors mediating this interaction. In addition, the evidence coming from in vitro, animal and human studies that support such inter‐organ crosstalk is thoroughly discussed.