The role of the immune system in the pathophysiology of osteoporosis.
The role of the immune system in the development of senile osteoporosis, which arises primarily through the effects of estrogen deficiency and secondary hyperparathyroidism, is slowly being unraveled. This review focuses on our current understanding of how the components of this complex-interlinked system are regulated and how these fit with previous models of senile and postmenopausal osteoporosis. There is certainly substantial evidence that bone remodeling is a tightly regulated, finely balanced process influenced by subtle changes in proinflammatory and inhibitory cytokines as well as hormones and cellular components that act primarily but not exclusively through the receptor activator of nuclear factor-kappaB (RANK)/RANK ligand/osteoprotegerin system. In addition, an acute or chronic imbalance in the system due to infection or inflammation could contribute to systemic (or local) bone loss and increase the risk of fracture. Although significant progress has been made, there remains much to be done in unraveling this complex interaction between the immune system and bone.
Clowes
Jackie A
JA
Mayo Clinic College of Medicine, Endocrine Research Unit, St Mary's Hospital, Rochester, MN 55905, USA. clowes.jackie@mayo.edu
Riggs
B Lawrence
BL
Khosla
Sundeep
S
D000375:Aging / Q000276:immunology; D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology; D002454:Cell Differentiation; D016207:Cytokines / Q000502:physiology; D004967:Estrogens / Q000502:physiology; D006023:Glycoproteins / Q000502:physiology; D006801:Humans; D007107:Immune System / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000502:physiology; D010010:Osteoclasts / Q000502:physiology; D010024:Osteoporosis / Q000209:etiology*; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology; D013601:T-Lymphocytes / Q000502:physiology; D014807:Vitamin D / Q000494:pharmacology
D002352:Carrier Proteins; D016207:Cytokines; D004967:Estrogens; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D014807:Vitamin D