Adiponectin is the metabolic linkage between bone mineral density and obesity
Adiponectin, a protein secreted from adipocytes, is the metabolic link that can partially explain the positive relationship between reduced susceptibility to fractures & bone mineral density and obesity, according to researchers at the University of Toronto, Faculty of Medicine, Toronto, Canada.
This study appeared in an issue of Experimental Biology and Medicine.
From News-Medical.Net:
The research team, Dr. Michael C. Archer, Earle W. McHenry Professor and Chair, Dr. Wendy E. Ward, Associate Professor, Dr. Kafi Ealey, Postdoctoral Fellow and predoctoral student Jovana Kaludjerovic, in the Department of Nutritional Sciences, investigated whether adiponectin modulates bone development using transgenic mice that overexpress this protein. These mice were initially developed by Dr. P. Scherer’s research group at Albert Einstein College of Medicine, N.Y. Bone mineral density and biomechanical strength properties, surrogate measures of fracture risk at multiple skeletal sites, were the outcomes used to assess bone development. Female mice overexpressing adiponectin had weaker vertebra at 8 weeks of age than control mice and this delay in bone development persisted through to the end of the study period, representing early adulthood. The weaker vertebra model compression fractures of the lumbar spine in humans, among the most common type of fragility fracture associated with low bone mass and osteoporosis. The strength of the femur neck, representing the hip, was also weaker in both females and males overexpressing adiponectin. Serum adiponectin levels were inversely correlated with femur bone mineral content, further emphasizing that a high level of adiponectin impedes bone development at not only the lumbar spine but also the hip. Whether or not the delay in bone development resolves in later life or is sustained and leads to an increased risk of fragility fracture, particularly during aging when bone loss rapidly occurs due to declining levels of sex steroids, requires further investigation.
It was remarked by Dr. Steven R. Goodman, Editor-in-Chief of Experimental Biology and Medicine, that these stimulating results offer considerable insights into adiponectin secretion, from adipocytes, loss of bone mineral density, and resulting increased fractures.
