Effects of eldecalcitol and ibandronate on secondary osteoporosis and muscle wasting in rats with adjuvant-induced arthritis

OBJECTIVES: Rheumatoid arthritis (RA) is characterized by chronic inflammation of the synovium, progressive erosion of the articular cartilage, and joint destruction. RA also causes secondary osteoporosis and muscle wasting. We investigated the effects of ibandronate (IBN), a bisphosphonate; eldecalcitol (ELD), an active vitamin D3 derivative; and combination treatment with both agents on secondary osteoporosis and muscle wasting using adjuvant-induced arthritis rats. METHODS: Arthritis was induced in 8-week-old male Lewis rats. Rats were randomized into 4 treatment groups and an untreated normal control group: IBN (subcutaneously, once every 2 weeks, 10 µg/kg), ELD (orally, once daily, 30 ng/kg/day), IBN + ELD, vehicle, and control. Paw thickness measurements were performed for evaluation of arthritis. The femur was scanned using dual-energy X-ray absorptiometry. Cross-sectional areas of left tibialis and anterior muscle fibers and the expression of MuRF1, atrogin-1, MyoD, and myogenin in the gastrocnemius muscle were measured to evaluate muscle wasting. RESULTS: IBN and/or ELD increased bone mineral density (BMD) in the femur. In addition, there was an additive effect of combination treatment compared with single treatments for BMD. However, IBN and/or ELD did not inhibit muscle wasting in adjuvant-induced arthritis rats. CONCLUSIONS: Combination treatment with IBN and ELD may be effective for secondary osteoporosis associated with RA. Other treatments are necessary for muscle wasting associated with RA. Studies in humans are needed to confirm these findings.

Bilateral stress fracture of the fibulae and periostitis of the tibiae

This study describes a unique case of bilateral stress fractures of the fibulae and provides a literature review. Clinical Presentation and Intervention: A 16-year-old female badminton player presented with pain around the bilateral distal lateral legs. She had mild bilateral varus deformity at the knee joint, and the bilateral ankles showed valgus deformity in standing posture. Radiographs and computed tomography showed periosteal reactions on the bilateral distal fibulae. Technetium-99m bone scintigraphy demonstrated increased uptake in the bilateral distal fibulae and the bilateral middle third of the tibiae. A diagnosis of bilateral distal fibular stress fractures was made. She was advised to stop playing badminton until the symptoms disappeared. Varus deformity of the knee and valgus deformity of the ankle may have influenced the mechanism underlying bilateral symmetric stress fractures