Exercise Interventions for the Prevention and Treatment of Sarcopenia. A Systematic Umbrella Review.

OBJECTIVES: The aim of this systematic review is to provide an overview of the efficacy of different exercise interventions to counter sarcopenia in older adults. This review will allow the Belgian Society of Gerontology and Geriatrics and other scientific societies to formulate specific exercise recommendations in their Clinical Guidelines for Sarcopenia. DESIGN: We used the method of a systematic umbrella-review. Based on the level of evidence, we formulated specific recommendations for clinical practice. METHODS: Two databases (Pubmed and Web Of Science) were searched systematically and methodological quality of the reviews was assessed. Extracted data was than mapped to an exercise category and an overall synthesis (bottom line statements) was formulated for each of these exercise categories. Subsequently, we assigned a rating of the quality of the evidence supporting each bottom line statement. RESULTS: We identified 14 systematic reviews or meta-analyses, encompassing four exercise categories: resistance training, resistance training + nutritional supplementation, multimodal exercise programmes and bloodflow restriction training. Importantly, very few systematic reviews or meta-analyses clearly mentioned baseline sarcopenia status. There is high quality evidence for a positive and significant effect of resistance training on muscle mass, muscle strength, and physical performance. The added effect of nutritional supplementation for resistance training on muscle function appears limited. Blood flow restriction training is a novel training method that has a significant impact on muscle strength. CONCLUSION: Since sarcopenia is affecting all skeletal muscles in the body, we recommend training the large muscle groups in a total body approach. Although low-intensity resistance training (≤50% 1RM) is sufficient to induce strength gains, we recommend a high-intensity resistance training program (i.e. 80% 1RM) to obtain maximal strength gains. Multimodal exercises and blood flow restriction resistance training may be considered as well.

Interaction with telencephalin and the amyloid precursor protein predicts a ring structure for presenilins.

The carboxyl terminus of presenilin 1 and 2 (PS1 and PS2) binds to the neuron-specific cell adhesion molecule telencephalin (TLN) in the brain. PS1 deficiency results in the abnormal accumulation of TLN in a yet unidentified intracellular compartment. The first transmembrane domain and carboxyl terminus of PS1 form a binding pocket with the transmembrane domain of TLN. Remarkably, APP binds to the same regions via part of its transmembrane domain encompassing the critical residues mutated in familial Alzheimer's disease. Our data surprisingly indicate a spatial dissociation between the binding site and the proposed catalytic site near the critical aspartates in PSs. They provide important experimental evidence to support a ring structure model for PS.