Physiological and pathophysiological bone turnover - role of the immune system.
Osteoporosis develops when the rate of osteoclastic bone breakdown (resorption) exceeds that of osteoblastic bone formation, which leads to loss of BMD and deterioration of bone structure and strength. Osteoporosis increases the risk of fragility fractures, a cause of substantial morbidity and mortality, especially in elderly patients. This imbalance between bone formation and bone resorption is brought about by natural ageing processes, but is frequently exacerbated by a number of pathological conditions. Of importance to the aetiology of osteoporosis are findings over the past two decades attesting to a deep integration of the skeletal system with the immune system (the immuno-skeletal interface (ISI)). Although protective of the skeleton under physiological conditions, the ISI might contribute to bone destruction in a growing number of pathophysiological states. Although numerous research groups have investigated how the immune system affects basal and pathological osteoclastic bone resorption, recent findings suggest that the reach of the adaptive immune response extends to the regulation of osteoblastic bone formation. This Review examines the evolution of the field of osteoimmunology and how advances in our understanding of the ISI might lead to novel approaches to prevent and treat bone loss, and avert fractures.
The Atlanta Department of Veterans Affairs Medical Center, 1670 Clairmont Road, Decatur, Georgia, 30033, USA.|Department of Medicine, Division of Endocrinology and Metabolism and Lipids, Emory University School of Medicine, 101 Woodruff Circle, 1305 WMB, Atlanta, Georgia 30322, USA.
M Neale
MN
Weitzmann
Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, 49 Jesse Hill Jr Drive, Atlanta, Georgia 30303, USA.|Grady Healthcare System, 80 Jesse Hill Jr Drive SE, Atlanta, Georgia, 30303, USA.
Ighovwerha
I
Ofotokun
D000818:Animals; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000276:immunology* / Q000378:metabolism* / Q000503:physiopathology; D016723:Bone Remodeling / Q000502:physiology*; D001862:Bone Resorption / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology; D050723:Fractures, Bone / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D007107:Immune System / Q000502:physiology*; D010024:Osteoporosis / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology