Editorial: Inter-organ crosstalk during exercise in health and disease: Extracellular vesicles as new kids on the block

KEYWORDS extracellular vesicle (EV), exercise, myokines, exosomes, microRNA (microRNA) Editorial on the Research Topic Inter-organ crosstalk during exercise in health and disease: Extracellular vesicles as new kids on the block Within exercise physiology, the study of factors potentially mediating interorgan crosstalk during and after exercise is a fascinating field of research. As exercise activates a plethora of metabolic pathways in several tissues, organs and systems, examining the underlying biological mechanisms contributing to exercise related metabolic benefits is imperative. Since two decades, the skeletal muscle is known to secrete humoral factors into the circulation in response to exercise, originally described as "myokines" by Pedersen et al. (2003). These myokines are now well known and extensively studied in the field of exercise science (Pedersen and Febbraio, 2012). Interestingly, exercise also triggers other metabolic organs to release similar factors arising from the heart, liver, white and brown adipose tissue, and the nervous system (Chow et al., 2022). These "exerkines" (Safdar et al., 2016) have been recognized to comprise an extensive range of biologically active signalling molecules, including cytokines, lipids, metabolites and (noncoding) nucleic acids, as recently reviewed (Chow et al., 2022). Extracellular vesicles (EVs) and their role as carrier particles for molecular signals became of specific interest in the exerkine field, as EVs are considered (co-)drivers of exercise-induced interorgan crosstalk (Whitham et al., 2018; Vechetti et al., 2021). Differentiated by both their size and nature of vesicular biogenesis, EVs can be primarily classified as exosomes, microvesicles and apoptotic bodies although some overlap does exist between these classifications. EVs may enclose plenty of material, including lipids, proteins and nucleic acids (Théry et al., 2018). Indeed, pioneering EV-related exercise studies have shown an increase in the circulating number of EVs after a single bout of exercise (Brahmer et al., 2019; Frühbeis et al., 2015; Oliveira et al., 2018; Whitham et al., 2018), with recent in vivo research estimating about 5% of circulating, tetraspanin-positive EVs to be muscle-derived (Estrada et al., 2022). However, the frequent lack of rigorous characterization, purification and/or quantification of EVs (which ideally requires a combination of multiple methodologies) makes the understanding of the role of EVs in exercise physiology rather hard (Darragh et al., 2021) and argues for standard approaches and reporting on EV-related exercise science. Nevertheless, many points need to be clarified, but as the interest in EVs research from an exercise and health We sincerely thank all authors and reviewers who participated in the Research Topic.