Toshitaka Nakamura

Basic fibroblast growth factor (FGF-2), an important modulator of cartilage and bone growth and differentiation, is expressed and regulated in osteoblastic cells. To investigate the role of FGF-2 in bone, we examined mice with a disruption of the Fgf2 gene. Measurement of trabecular bone architecture of the femoral metaphysis of Fgf2(+/+) and Fgf2(-/-) adult mice by micro-CT revealed that the platelike trabecular structures were markedly reduced and many of the connecting rods of trabecular bone were lost in the Fgf2(-/-) mice. Dynamic histomorphometry confirmed a significant decrease in trabecular bone volume, mineral apposition, and bone formation rates. In addition, there was a profound decreased mineralization of bone marrow stromal cultures from Fgf2(-/-) mice. This study provides strong evidence that FGF-2 helps determine bone mass as well as bone formation.

INTRODUCTION: In 1998, the first Japanese practice guidelines on osteoporosis was published. It has been updated several times, with the most recent being the full-scale 2011 edition and its abridged edition. The present guidelines provide information for the managements of primary osteoporosis in postmenopausal women and men over 50 years old, a summary of the evidence for the treatment of secondary osteoporosis, and a summary of the evidence for the prevention of osteoporosis in younger people. METHOD: The present Executive Summary is primarily based on the content of the 2011 Japanese abridged edition. One of the key changes is revision of the criteria for initiation of pharmacological treatment, along with an introduction of the fracture risk factors used in FRAX®. Key figures and tables were selected from the Japanese abridged edition and a reference list was added. RESULT AND CONCLUSIONS: The essential points of the Japanese practice guidelines on osteoporosis were translated into English for the first time. It is hoped that the content of the guidelines becomes known throughout the world.

CONTEXT: Weekly teriparatide injection at a dose of 56.5 μg has been shown to increase bone mineral density. OBJECTIVE: A phase 3 study was conducted to determine the efficacy of once-weekly teriparatide injection for reducing the incidence of vertebral fractures in patients with osteoporosis. DESIGN AND SETTING: In this randomized, multicenter, double-blind, placebo-controlled trial conducted in Japan, the incidence of morphological vertebral fractures by radiographs was assessed. PATIENTS: Subjects were 578 Japanese patients between the ages of 65 and 95 yr who had prevalent vertebral fracture. INTERVENTION: Subjects were randomly assigned to receive once-weekly s.c. injections of teriparatide (56.5 μg) or placebo for 72 wk. MAIN OUTCOME MEASURE: The primary endpoint was the incidence of new vertebral fracture. RESULTS: Once-weekly injections of teriparatide reduced the risk of new vertebral fracture with a cumulative incidence of 3.1% in the teriparatide group, compared with 14.5% in the placebo group (P < 0.01), and a relative risk of 0.20 (95% confidence interval, 0.09 to 0.45). At 72 wk, teriparatide administration increased bone mineral density by 6.4, 3.0, and 2.3% at the lumbar spine, the total hip, and the femoral neck, respectively, compared with the placebo (P < 0.01). Adverse events (AE) and the dropout rates by AE were more frequently experienced in the teriparatide group, but AE were generally mild and tolerable. CONCLUSION: Weekly s.c. administration of teriparatide at a dose of 56.5 μg may provide another option of anabolic treatments in patients with osteoporosis at higher fracture risk.