Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành y đề tài: T cells and post menopausal osteoporosis in murine models. | Available online http content 9 2 102 Commentary T cells and post menopausal osteoporosis in murine models Roberto Pacifici Division of Endocrinology Metabolism and Lipids Department of Medicine Emory University School of Medicine Atlanta GA 30322 USA Corresponding author Roberto Pacifici Published 5 March 2007 This article is online at http content 9 2 102 2007 BioMed Central Ltd Arthritis Research Therapy 2007 9 102 doi ar2126 Abstract Estrogen deficiency is one of the most frequent causes of osteoporosis in women and a possible cause of bone loss in men. But the mechanism involved remains largely unknown. Estrogen deficiency leads to an increase in the immune function which culminates in an increased production of tumor necrosis factor TNF by activated T cells. TNF increases osteoclast formation and bone resorption both directly and by augmenting the sensitivity of maturing osteoclasts to the essential osteoclastogenic factor RANKL the RANK ligand . Increased T cell production of TNF is induced by estrogen deficiency via a complex mechanism mediated by antigen presenting cells and the cytokines IFNy IL-7 and transforming growth factor-p. The experimental evidence that suggests that estrogen prevents bone loss by regulating T cell function and the interactions between immune cells and bone is reviewed here. Estrogen deficiency is the most frequent cause of bone loss in humans. Bone loss results both from decreased ovarian production of sex steroids and the increase in follicle stimulating hormone FSH production induced by estrogen deficiency. FSH is now known to directly stimulate the production of tumor necrosis factor TNF a potent osteoclastogenic cytokine from bone marrow granulocytes and macrophages 1 2 . While FSH is likely to play a relevant role in the mechanism by which natural and surgical menopause lead to bone loss this article will focus on the direct FSH independent .
