Exercise Training and Circulating Small Extracellular Vesicles: Appraisal of Methodological Approaches and Current Knowledge

Abstract

In response to acute exercise, an array of metabolites, nucleic acids, and proteins are enriched in circulation. Collectively termed “exercise factors,” these molecules represent a topical area of research given their speculated contribution to both acute exercise metabolism and adaptation to exercise training. In addition to acute changes induced by exercise, the resting profile of circulating exercise factors may be altered by exercise training. Many exercise factors are speculated to be transported in circulation as the cargo of extracellular vesicles (EVs), and in particular, a sub-category termed “small EVs.” This review describes an overview of exercise factors, small EVs and the effects of exercise, but is specifically focused on a critical appraisal of methodological approaches and current knowledge in the context of changes in the resting profile small EVs induced by exercise training, and the potential bioactivities of preparations of these “exercise-trained” small EVs. Research to date can only be considered preliminary, with interpretation of many studies hindered by limited evidence for the rigorous identification of small EVs, and the conflation of acute and chronic responses to exercise due to sample timing in proximity to exercise. Further research that places a greater emphasis on the rigorous identification of small EVs, and interrogation of potential bioactivity is required to establish more detailed descriptions of the response of small EVs to exercise training, and consequent effects on exercise adaptation.

Association of low physical activity with higher respiratory tract infections frequency among pre-school children

“…EVs offer a promising diagnostic potential for the beneficial effects of PA in organs beyond the skeletal muscle. 55,56 Investigating the aforesaid mechanisms in children would help to establish specific doses of PA that stimulate the autoimmune response but do not induce immune imbalance.…”

Physical activity-correlated changes in plasma enzyme concentrations in fragile sarcolemmal muscular dystrophies

“…Prior studies have demonstrated that these enzymes may be released by damaged muscle [41][42][43] . The mechanism(s) by which the enzymes enter the blood may combine leakage through sarcolemma wounds, exocytosis, extracellular vesicles [44][45][46] and activity-dependent lymph flow 47,48 .…”

Exercise training-induced changes in exerkine concentrations may be relevant to the metabolic control of type 2 diabetes mellitus patients: A systematic review and meta-analysis of randomized controlled trials

“…Exerkines are increasingly recognized as critical intermediaries of exerciserelated changes and health benefits, mainly due to their role in inter-organ and systemic communication and coordination. 5 Most of the literature associates the benefits of exerkines with aerobic exercise; 6 however, the effects of resistance or combined exercise (i.e., aerobic plus resistance training), intensity (i.e., light, moderate), length of program, frequency and/or duration of the session are less studied. 7 Furthermore, the relationship between exerkines and response in individuals with T2DM remains unexplored.…”