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As the aging population increases in China, the incidence of osteoporosis increases as well. Because of the progress in osteoporosis study, the pathogenesis of osteoporosis has increasingly drawn attention in the recent years. In the traditional concept, the cause of osteoporosis includes endocrine disturbance, metabolic disturbance, and mechanical factor. However, the concept of osteoimmunology has been suggested recently. It is considered that immune system and immune factor play an important role in the development of osteoporosis. Osteoimmunology is a field of research dedicating to the study of the interactions between the immune system, the hemopoietic system, and the bone. The cells in the immune system that regulate bone cells and the hemopoietic function are T lymphocytes. These cells secrete inflammatory cytokines and Wnt ligands that promote bone resorption and stimulate bone formation. In addition, T cells regulate bone homeostasis by cross talking with BM stromal cells and osteoblastic cells via CD40 ligand (CD40L) and other costimulatory molecules. This article describes the effect of immune factor on the development of osteoporosis. [ABSTRACT FROM AUTHOR]

Idiopathic juvenile osteoporosis (IJO) is a rare primary form of osteoporosis of unknown etiology that develops in a previously healthy child. IJO is characterized by repeated fractures, including vertebral compression fractures. It is usually a self-limiting disease that spontaneously resolves after puberty, but in some cases it may result in severe deformities and functional impairment. There are probably the following reasons about etiological factors and pathogenesis in IJO: 1) Imbalance between bone formation and bone resorption; 2) Adolescent growth burst and bone mass increase; 3) Abnormal metabolic regulation factors of bone; 4) Abnormal collagen synthesis. IJO runs an acute course, usually over a period of 2 to 4 years, during which time there is growth arrest and multiple fractures, and then the disease remits. Both the axial and the appendicular skeleton are affected. The severe cases may have fractures of the vertebrae and the long bones, particularly in the metaphyses, that lead to pain in the back, foot, hip and extremities, muscle weakness, limitation of free movement, deformity, and unique gait because of difficulty in walking. The diagnosis of IJO is based both on the exclusion of other diseases and on its own positive features. The diagnosis of IJO is best made from its X-ray features, which include multiple vertebral compression fractures and fractures of the long bones, especially around the weight-bearing joints. Treatment of IJO is extremely complicated. The basic strategy of treatment is to protect the spine and to avoid the occurring of fractures and deformity until remission occurs. Supportive care is instituted promptly in anticipation of spontaneous recovery with the onset of puberty. [ABSTRACT FROM AUTHOR]

Cummings et al proposes direct-goal therapy of osteoporosis (OP) and regards bone mineral density (BMD), fracture risk, and bone turnover markers (BTM) as important parameters in order to optimize treatment strategies. The establishment of the goal plays an important role in clinical application, which improves reasonable choice of initial drug therapy and follow-up on treatment, also improves assessment of potent effects on BMD and fracture risk. In addition, it helps clinicians to decide when to switch and when to stop. Once the goal has been established, treatment should follow it. We should choose the treatment that has a reasonable probability of reaching that goal and periodically follow-up to approach the goal as most appropriate programs. Although there are still many problems and issues to be discussed, direct-goal therapy of OP has become an inevitable trend and has far-reaching significance. This paper reviews the direct-goal therapy of osteoporosis and current research consensus. [ABSTRACT FROM AUTHOR]

Objective To construct two vectors expressing siRNA targeting DKK1 gene and to investigate the treatment effect on rat osteoporosis (OP). Methods Twelve-week-old OP rats were randomly divided into 5 groups, including control group, model group, empty vector group, DKK1-siRNA1 group, and DKK1-siRNA2 group, with 10 rats in each group. Rats in latter 4 groups were given dexamethasone for 12 weeks continuously, but rats in control group were injected normal saline. The model of osteoporosis was identified. Two vectors containing DKK1-silencing siRNA were constructed successfully. They were injected through tail vein of OP rats in therapy group, while rats in the control group and model group were injected with the same volume of PBS, and rats in empty vector group were injected with the same volume of empty vector. Bone tissue was sliced to observe if siRNA can target to bone. The expression of DKK1 mRNA in the femur was detected using RT-PCR and DKK1 protein was detected using immunohistochemistry. Serum levels of BALP, Col-I, and TRAP in each group were detected using ELISA method. Bone mineral density and the pathological changes of the femur were observed. Results (1) siRNA eukaryotic expression vectors were successfully constructed. (2) Comparing to control group, bone mineral density of the proximal femurs in model group, empty vector group, and DKK1-siRNA groups decreased significantly (P<0.05). The number of trabecular reduced and the trabecular broke in these groups, but the trabecular remained intact in control group. (3) DKK1-siRNA can target to the bone. (4) Expression of DKK1-mRNA in blood and DKK1 protein in bone were significantly decreased in therapy groups. (5) Comparing to model group and empty vector group, serum BALP and Col-I levels in therapy groups significantly decreased (P <0.05), but TRAP level increased significantly (P<0.05). (6) Bone mineral density of the proximal femur of rats between each group had no significant difference (P >0.05). (7) Formation of new trabeculae and reduction of trabecular damage were found in therapy group. Conclusion DKK1-siRNA promotes bone formation, inhibits bone resorption, and reduces the damage of bone construction. [ABSTRACT FROM AUTHOR]

Bone diseases are one kind of the motor system diseases involving of bone, joint, tendons and fascia. They include osteoporosis, rickets, osteosclerosis, femoral head necrosis, fractures, etc. Several factors affect the development of the diseases, such as genetic, environmental, endocrinal and nutritional factors. In addition to calcium, phosphorus and vitamins which arc associated with bone diseases, a number of trace elements are also involved in the growth, development and metabolism of the bone. Furthermore, various trace elements play the different roles in bone metabolism and diseases. Therefore, deficiency of trace elements, which participate in bone metabolism and regeneration, may cause the disorder of bone growth, resorption, and mineral deposition, leading to different types of bone diseases. This paper reviews the distribution of trace elements in the bone, the regulation of bone metabolism, bone diseases due to the deficiency of trace elements, and supplementation of trace elements for prevention and treatment of bone diseases, thus providing theoretical basis for clinical diagnosis and therapy of bone diseases for trace element deficiency. [ABSTRACT FROM AUTHOR]

Objective: To explore the prevalence and characteristics of main organ involvement in adult patients with polymyositis (PM) or dermatomyositis (DM) and determine their specific relative factors., Methods: Using unified questionnaire, we retrospectively collected the medical records of 1 387 confirmed adult PM/DM patients from 2007 to 2012 at 22 rheumatology centers in China. Statistical analyses were performed with chi-square or Fisher exact test and multivariate analyses with logistic regression., Results: A total of 1 387 patients were collected with 460 (33.2%) PM and 927 (66.8%) DM. The female:male ratio was 2.4: 1. Their onset age was ( 47 ± 14) years. A total of 1 031 (74.3%) patients had organ involvement. The prevalence of pulmonary involvement, arthritis, gastrointestinal and cardiac involvement were 44.6%, 32.3%, 21.9% and 20.3% respectively. The multivariate analysis indicated that older onset age (P < 0.01) was positively associated with pulmonary involvement while myalgia (P < 0.05) was negatively associated. Fever (P < 0.05), weight loss (P < 0.05) and Raynaud's phenomenon (P < 0.01) were positively associated with arthritis while muscle weakness (P < 0.05) negatively associated. Weight loss (P < 0.05), Raynaud's phenomenon (P < 0.01) and muscle weakness (P < 0.05) were positively associated with gastrointestinal involvement. Weight loss (P < 0.05) and swollen limbs (P < 0.05) were positively associated with cardiac involvement., Conclusion: The prevalence of organ involvement is high in adult PM/DM patients. Our study may aid the diagnosis of organ damage in PM/DM patients.