title: Exercise-induced effects on UCP1 expression in classical brown adipose tissue: a systematic review.
abstract: Understanding the impact of regular exercise training on uncoupling protein 1 (UCP1) activity in classical brown adipose tissue (CBAT) is vital to our knowledge of whole-body thermogenic activity. The purpose of this systematic review was to evaluate the available experimental evidence on the effect of regular exercise training on UCP1 expression in CBAT. We performed a literature search using PubMed (1966-2016), Scopus, and EMBASE (1974-2016). Studies in any language that examined the effect of regular exercise training on UCP1 expression in CBAT, and not white adipose tissue (WAT), were eligible. Reviews, editorials, and conference proceedings were excluded. Nine studies fulfilled the set criteria. Risk of bias was assessed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool. The quality of reporting the results in the included studies was assessed using the 38-item checklist of the Animal Research Reporting of In Vivo Experiments (ARRIVE). Based on the evidence available and a comprehensive analysis of different confounding factors, we conclude that regular exercise training does not represent a major stimulus of UCP1 expression in CBAT. However, regular exercise training may induce adaptive responses to CBAT thermogenic activity in cases where: (i) animals consume a high-fat diet, (ii) exercise is combined with cold exposure, and (iii) animals show endogenously low UCP1 levels. Finally, it is important to note an inconsistency in the results from the analysed studies, which may be attributed to a number of confounding factors, increased risk of bias, as well as low quality of reporting the results.
authors.affiliation: .
authors.forename: Andreas D
authors.identifier: http://orcid.org/0000-0002-9823-3915
authors.initials: AD
authors.lastname: Flouris
authors.affiliation: .
authors.forename: Petros C
authors.initials: PC
authors.lastname: Dinas
authors.affiliation: .
authors.forename: Angelica
authors.initials: A
authors.lastname: Valente
authors.affiliation: .
authors.forename: Cláudia Marlise Balbinotti
authors.initials: CMB
authors.lastname: Andrade
authors.affiliation: .
authors.forename: Nair Honda
authors.initials: NH
authors.lastname: Kawashita
authors.affiliation: .
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Sakellariou
mesh_terms: D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D015986:Confounding Factors, Epidemiologic; D004734:Energy Metabolism; D015444:Exercise; D005786:Gene Expression Regulation; D006801:Humans; D024101:Mitochondrial Proteins / Q000378:metabolism; D013696:Temperature; D022722:Thermogenesis; D000071256:Uncoupling Protein 1 / Q000235:genetics* / Q000378:metabolism
chemical_list: D024101:Mitochondrial Proteins; D000071256:Uncoupling Protein 1
keywords: BAT; cold exposure; obesity; physical activity; thermogenesis; uncoupling protein 1