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International Journal of Endocrinology
Volume 2014, Article ID 857270, 9 pages
http://dx.doi.org/10.1155/2014/857270
Research Article

Association of Irisin with Fat Mass, Resting Energy Expenditure, and Daily Activity in Conditions of Extreme Body Mass Index

1Laboratory of Molecular and Cellular Endocrinology, Health Research Institute of Santiago (IDIS), University Hospital of Santiago (XXIS/SERGAS) and Santiago de Compostela University (USC), 15706 Santiago de Compostela, Spain
2CIBER Fisiopatología de la Obesidad y la Nutrición (CIBERobn), 15706 Santiago de Compostela, Spain
3Obesidómica Group, Laboratory 3, Health Research Institute of Santiago (IDIS), University Hospital of Santiago (XXIS/SERGAS), 15706 Santiago de Compostela, Spain
4Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 08908 Barcelona, Spain
5Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, 08907 Barcelona, Spain
6Department of Clinical Sciences, School of Medicine, University of Barcelona, 08007 Barcelona, Spain
7Department of Psychological, Personality, Evaluation and Treatment of the University of Valencia, 46010 Valencia, Spain
8Department of Basic Psychology, Clinic and Psychobiology of the Jaume I University, Castelló, 12071 Castelló de la Plana, Spain
9Human Pharmacology and Clinical Neurosciences Research Group, Neuroscience Research Program, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
10Center for Genomic Regulation (CRG), 08003 Barcelona, Spain
11Centro de Investigación Biomédica en Red en Epidemiología y Salud Pública (CIBERESP), 08036 Barcelona, Spain
12Department of Diabetes, Endocrinology and Nutrition, Institut d’Investigació Biomèdica de Girona (IdlBGi), Hospital Dr Josep Trueta, Girona, Spain
13Department of Diabetes, Endocrinology and Nutrition, Hospital Cliínico Universitario Virgen de Victoria, 29010 Maálaga, Spain
14Department of Endocrinology and Nutrition, University Clinic de Navarra, University of Navarra, 31008 Pamplona, Spain

Received 12 December 2013; Revised 28 February 2014; Accepted 28 February 2014; Published 22 April 2014

Academic Editor: Maria L. Dufau

Copyright © 2014 María Pardo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

FNDC5/irisin has been recently postulated as beneficial in the treatment of obesity and diabetes because it is induced in muscle by exercise, increasing energy expenditure. However, recent reports have shown that WAT also secretes irisin and that circulating irisin is elevated in obese subjects. The aim of this study was to evaluate irisin levels in conditions of extreme BMI and its correlation with basal metabolism and daily activity. The study involved 145 female patients, including 96 with extreme BMIs (30 anorexic (AN) and 66 obese (OB)) and 49 healthy normal weight (NW). The plasma irisin levels were significantly elevated in the OB patients compared with the AN and NW patients. Irisin also correlated positively with body weight, BMI, and fat mass. The OB patients exhibited the highest REE and higher daily physical activity compared with the AN patients but lower activity compared with the NW patients. The irisin levels were inversely correlated with daily physical activity and directly correlated with REE. Fat mass contributed to most of the variability of the irisin plasma levels independently of the other studied parameters. Conclusion. Irisin levels are influenced by energy expenditure independently of daily physical activity but fat mass is the main contributing factor.