Melanocortin receptor expression is associated with reduced CRP in response to resistance training

Exercise Is Medicine: How Do We Implement It?

Exercise is well known to have beneficial effects on various disease states. In this paper, we broadly describe the fundamental concepts that are shared among various disease states, including obesity, type 2 diabetes (T2D), cardiovascular disease (CVD), heart failure (HF), cancer, and psychological well-being, and the beneficial effects of exercise training within these concepts. We highlight issues involved in implementing exercise recommendations and describe the potential impacts and challenges to medical professionals and patients. Problems are identified and discussed with respect to the future roles of professionals in the current built environment with its limited infrastructure to support current physical activity recommendations.

The effect of resistance exercise on the immune cell function in humans: A systematic review

BACKGROUND

Resistance exercise is beneficial for the immune system, including decreased susceptibility to infections and improved effectiveness of vaccinations. This review aims to provide a systematic analysis of the literature regarding the impact of resistance exercise on immune cells in the blood circulation.

MATERIALS AND METHODS

The protocol of this review followed the PRISMA guidelines and registered in PROSPERO (ID: CRD42020157834). PubMed and Web-of-Science were systematically searched for relevant articles. Outcomes were divided into two categories: 1) inflammatory gene expression or secretion of inflammation-related cytokines and 2) other aspects such as cell migration, proliferation, apoptosis, phagocytosis, and redox status.

RESULTS

Thirty intervention studies were included in this review, of which 11 articles were randomized controlled trials and six non-randomized controlled trials. Although only resistance exercise interventions were included, there was a high heterogeneity regarding specific exercise modalities. The most frequently studied outcome measures were the gene and protein expression levels in peripheral blood mononuclear cells (PBMC). This review reveals that already one acute exercise bout activates the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway in PBMC. Although resistance exercise induces an acute cytosolic oxidative stress response, the antioxidant enzyme expression is improved after resistance training period. Natural killer cell activity increases in older but decreases in younger adults immediately after a resistance exercise bout. Moreover, resistance exercise improves neutrophil phagocytic activity. Finally, effects on lymphocyte proliferation remain unclear.

CONCLUSIONS

The results of this systematic review demonstrate that resistance exercise has beneficial effects on several aspects of immune cell function both in young and older individuals. Acute changes in immune cell function occur already after a single bout of resistance exercise. However, regular resistance training during several weeks seems necessary to obtain beneficial adaptations that can be related to better immunity and reduced inflammation. The effects documented in this review confirm the beneficial effects of resistance exercise in young as well as older persons on the immune cell function.

A mouse model for a partially inactive obesity-associated human MC3R variant

We previously reported children homozygous for two MC3R sequence variants (C17A+G241A) have greater fat mass than controls. Here we show, using homozygous knock-in mouse models in which we replace murine Mc3r with wild-type human (MC3R^hWT/hWT) and double-mutant (C17A+G241A) human (MC3R^hDM/hDM) MC3R, that MC3R^hDM/hDM have greater weight and fat mass, increased energy intake and feeding efficiency, but reduced length and fat-free mass compared with MC3R^hWT/hWT. MC3R^hDM/hDM mice do not have increased adipose tissue inflammatory cell infiltration or greater expression of inflammatory markers despite their greater fat mass. Serum adiponectin levels are increased in MC3R^hDM/hDM mice and MC3R^hDM/hDM human subjects. MC3R^hDM/hDM bone- and adipose tissue-derived mesenchymal stem cells (MSCs) differentiate into adipocytes that accumulate more triglyceride than MC3R^hWT/hWT MSCs. MC3R^hDM/hDM impacts nutrient partitioning to generate increased adipose tissue that appears metabolically healthy. These data confirm the importance of MC3R signalling in human metabolism and suggest a previously-unrecognized role for the MC3R in adipose tissue development.

The melanocortin receptor, MC3R, regulates organismal energy homeostasis. Here, Lee et al. create knock-in mice with the a mutated version of the human MC3R receptor found in obese children, and show these mice have more fat and smaller bone, yet are by and large metabolically healthy.

C-Reactive Protein and Resistance Exercise in Community Dwelling Old Adults

OBJECTIVES

C-reactive protein (CRP), an acute phase reactant, has been associated with atherosclerosis and has also been discussed as a target for intervention. The effects of resistance exercise on CRP are currently not clear. The present analysis investigated the response of CRP to resistance exercise in old adults.

DESIGN

Intervention study.

SETTING

Community.

PARTICIPANTS

Old Icelandic adults (N = 235, 73.7 ± 5.7 years, 58.2% female).

INTERVENTION

Twelve-week resistance exercise program (3 times/week; 3 sets, 6-8 repetitions at 75-80% of the 1-repetition maximum) designed to increase strength and muscle mass of major muscle groups.

MEASUREMENTS

C-reactive protein (CRP).

RESULTS

Mean CRP levels were 7.1 ± 4.6 mg/dL at baseline, thirty-six (15.6%) subjects had abnormally high CRP (>10 mg/L) values at baseline. After the resistance exercise program the overall changes in CRP were minor and not significant. However, CRP decreased considerably in participants with high CRP at baseline (-4.28 ± 9.41 mg/L; P = 0.015) but increased slightly in participants with normal CRP (0.81 ± 4.58 mg/L, P = 0.021).

CONCLUSIONS

Our study shows that the concentrations of circulating CRP decreased considerably after a 12-week resistance exercise program in participants with abnormally high CRP at baseline, possibly reducing thus risk for future disease. CRP changed little in participants with normal CRP at the start of the study.

The use of periodization in exercise prescriptions for inactive adults: A systematic review

BACKGROUND

Periodization of exercise is a method typically used in sports training, but the impact of periodized exercise on health outcomes in untrained adults is unclear.

PURPOSE

This review aims to summarize existing research wherein aerobic or resistance exercise was prescribed to inactive adults using a recognized periodization method.

METHODS

A search of relevant databases, conducted between January and February of 2014, yielded 21 studies published between 2000 and 2013 that assessed the impact of periodized exercise on health outcomes in untrained participants.

RESULTS

Substantial heterogeneity existed between studies, even under the same periodization method. Compared to baseline values or non-training control groups, prescribing periodized resistance or aerobic exercise yielded significant improvements in health outcomes related to traditional and emerging risk factors for cardiovascular disease, low-back and neck/shoulder pain, disease severity, and quality of life, with mixed results for increasing bone mineral density.

CONCLUSIONS

Although it is premature to conclude that periodized exercise is superior to non-periodized exercise for improving health outcomes, periodization appears to be a feasible means of prescribing exercise to inactive adults within an intervention setting. Further research is necessary to understand the effectiveness of periodizing aerobic exercise, the psychological effects of periodization, and the feasibility of implementing flexible non-linear methods.