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We investigated the effects of biologics for rheumatoid arthritis (RA) patients on bone mineral density (BMD) and bone metabolic markers (BMM), retrospectively, and also clarified the effects of bisphosphonates (alendronate or risedronate 35 mg/week) and glucocorticoids. Participants in this study comprised 219 patients with RA, including 117 patients treated with biologics (infliximab, n = 90; etanercept, n = 27) and 102 patients with conventional disease-modifying anti-rheumatic drugs (DMARDs) for 1 year. Changes in BMD at the lumbar spine and total hip and BMMs [urinary type I collagen cross-linked N-telopeptide (NTX) and bone-specific alkaline phosphatase] were measured. BMD of the lumbar spine in both groups and total hip BMD in the biologics group were unchanged during treatment with biologics. However, BMD of the total hip was significantly decreased in the DMARDs group (from 0.731 ± 0.135 to 0.706 ± 0.135 g/cm). Patients receiving glucocorticoids without bisphosphonates showed significant decrease in BMD of the total hip compared with patients not receiving glucocorticoids or receiving glucocorticoids with bisphosphonates in both biologics and DMARDs groups. Furthermore, BMD of the lumbar spine increased ( p < 0.05) for patients in the biologics group who received bisphosphonates. NTX was significantly decreased only in the biologics group. Multiple regression analysis showed that BMD and bone metabolic marker levels correlated positively with bisphosphonate and biologics use and negatively with glucocorticoid use. BMD of the total hip was maintained in the patients using biologics without glucocorticoids or with bisphosphonates, but it was not maintained in the DMARDs patients, even without glucocorticoids or with bisphosphonates. Even if biologics have protective effect against bone loss of RA patients, we should consider reducing the dose of glucocorticoids and adding bisphosphonates for the treatment of osteoporosis. [ABSTRACT FROM AUTHOR]

Etanercept (ETN), which is a recombinant human soluble tumor necrosis factor (TNF) receptor that inhibits TNF activity, is effective in the treatment of rheumatoid arthritis. We investigated the effect of ETN on recombinant human bone morphogenetic protein-2 (rhBMP-2)-induced ectopic bone formation in vivo. A block copolymer composed of poly-D,L-lactic acid with random insertion of p-dioxanone and polyethylene glycol (PLA-DX-PEG polymer) was used as the delivery system. Polymer discs (6 mm, 30 mg) containing 5 microg rhBMP-2 were implanted into the left dorsal muscle pouch of mice (n = 50). In the systemic administration groups (n = 5 per group), ETN was subcutaneously injected (25 mg/human = 12.5 microg/mouse) twice per week in a dose-dependent manner (placebo, 12.5 x 10(-3), 12.5 x 10(-1), 12.5, 125 microg), whereas a single dose of ETN (placebo, 12.5 x 10(-3), 12.5 x 10(-1), 12.5, 125 microg) was embedded in each rhBMP-2 polymer disc in the local administration groups (n = 5 per group). Three weeks after implantation, the mice were killed and the implants were analyzed. Implants in the optimally dosed groups had increased radiodensity, which was consistent with a significant increase in bone mineral content of the ossicles. Bone histomorphology revealed a significant increase in bone volume/total volume, number of osteoblasts, osteoblast surface/bone surface, and a significant decrease in the number of osteoclasts, osteoclast surface/bone surface in the optimal dosed systemic and locally administered groups. These data suggest that the optimal dose of ETN, administered either systemically or locally, enhanced the bone-inducing capacity of BMP with no apparent adverse systemic effects. [ABSTRACT FROM AUTHOR]

Noggin is a major extracellular antagonist to bone morphogenetic proteins (BMPs) which binds to BMPs and blocks binding of them to BMP-specific receptors and negatively regulates BMP-induced osteoblastic differentiation. In this study, we investigated the effect of noggin silencing by transfection of small interfering RNA (siRNA) on BMP-induced osteoblastic differentiation in vitro and ectopic bone formation in vivo induced by recombinant human BMP-2 (rhBMP-2). Noggin mRNA expression was up-regulated in response to rhBMP-2 in C2C12 cells, a myoblastic cell line, in dose- and time-dependent fashion as determined by real-time RT-PCR assay. Silencing of noggin expression by transfection of noggin siRNA suppressed BMP-stimulated noggin expression, resulting in acceleration of BMP-induced osteoblastic differentiation. For in vivo noggin silencing, siRNA was injected locally into back muscles and transfected into local cells by electroporation, where rhBMP-2-retaining (5 microg) collagen disks had been surgically placed. The implants were harvested at 2 weeks after surgery from experimental and control group mice and analyzed by radiological and histological methods. As a result, bone mineral content of ossicles ectopically induced by rhBMP-2 was significantly increased by silencing of noggin. Our findings suggest that silencing of noggin enhances the osteoblastic differentiation of BMP-responding cells in vitro and new bone formation induced by rhBMP-2 in vivo by eliminating negative regulation of the effects of BMP. RNA interference might be useful for intensifying the effects of BMP in promoting new bone (callus) formation in repair of damaged bone. [ABSTRACT FROM AUTHOR]