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International Journal of Endocrinology
Volume 2014 (2014), Article ID 278316, 10 pages
http://dx.doi.org/10.1155/2014/278316
Research Article

Abdominal Fat and Sarcopenia in Women Significantly Alter Osteoblasts Homeostasis In Vitro by a WNT/β-Catenin Dependent Mechanism

1Section of Health Sciences, Department of Movement, Human and Health Sciences, “Foro Italico” University of Rome, Largo Lauro De Bosis 15, 00195 Rome, Italy
2Section of Medical Pathophysiology, Department of Experimental Medicine, Endocrinology and Nutrition, “Sapienza” University of Rome, Italy

Received 31 January 2014; Revised 14 April 2014; Accepted 29 April 2014; Published 20 May 2014

Academic Editor: Małgorzata Kotula-Balak

Copyright © 2014 Francesca Wannenes 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

Obesity and sarcopenia have been associated with mineral metabolism derangement and low bone mineral density (BMD). We investigated whether imbalance of serum factors in obese or obese sarcopenic patients could affect bone cell activity in vitro. To evaluate and characterize potential cellular and molecular changes of human osteoblasts, cells were exposed to sera of four groups of patients: (1) affected by obesity with normal BMD (O), (2) affected by obesity with low BMD (OO), (3) affected by obesity and sarcopenia (OS), and (4) affected by obesity, sarcopenia, and low BMD (OOS) as compared to subjects with normal body weight and normal BMD (CTL). Patients were previously investigated and characterized for body composition, biochemical and bone turnover markers. Then, sera of different groups of patients were used to incubate human osteoblasts and evaluate potential alterations in cell homeostasis. Exposure to OO, OS, and OOS sera significantly reduced alkaline phosphatase, osteopontin, and BMP4 expression compared to cells exposed to O and CTL, indicating a detrimental effect on osteoblast differentiation. Interestingly, sera of all groups of patients induced intracellular alteration in Wnt/β-catenin molecular pathway, as demonstrated by the significant alteration of specific target genes expression and by altered β-catenin cellular compartmentalization and GSK3β phosphorylation. In conclusion our results show for the first time that sera of obese subjects with low bone mineral density and sarcopenia significantly alter osteoblasts homeostasis in vitro, indicating potential detrimental effects of trunk fat on bone formation and skeletal homeostasis.