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Fukuoka-shi, Japan

The purpose of the present study was to determine whether teriparatide and monthly minodronic acid would have an additive effect on cancellous bone mass in ovariectomized rats. Seven-week-old female Sprague-Dawley rats were randomized into five groups of 10 animals each, including a sham-operation. +. vehicle group, an ovariectomy (OVX). +. vehicle group, an OVX. +. minodronic acid (6. μg/kg. s.c., every 4. weeks) group, an OVX. +. teriparatide (20. μg/kg. s.c., daily) group, and an OVX. +. minodronic acid. +. teriparatide group. After the 12-week experimental period, static and dynamic histomorphometric analyses were performed on the cancellous bone of the tibial proximal metaphysis. OVX decreased the bone volume per total volume (BV/TV) and the trabecular number (Tb.N) and increased the trabecular separation (Tb.Sp) as a result of increased bone remodeling. Minodronic acid prevented the OVX-induced decreases in BV/TV, while teriparatide increased the BV/TV and trabecular width (Tb.Wi) beyond the values of the sham controls. Minodronic acid prevented, but teriparatide only mitigated, the OVX-induced decrease in Tb.N, although both drugs similarly prevented the OVX-induced increase in Tb.Sp. A combination of teriparatide and minodronic acid further increased the BV/TV and Tb.N and decreased the Tb.Sp as a result of the suppression of bone remodeling, compared with teriparatide alone. These results suggest the differential effect of teriparatide and monthly minodronic acid on cancellous bone structure and the additive effect of the two drugs on cancellous bone mass in OVX rats. © 2014 Elsevier Inc. Source


Iwamoto J.,Keio University | Sato Y.,Mitate Hospital
Therapeutics and Clinical Risk Management | Year: 2014

An open-label randomized controlled trial was conducted to clarify the effect of eldecalcitol (ED) on body balance and muscle power in postmenopausal osteoporotic women treated with bisphosphonates. A total of 106 postmenopausal women with osteoporosis (mean age 70.8 years) were randomly divided into two groups (n=53 in each group): a bisphosphonate group (control group) and a bisphosphonate plus ED group (ED group). Biochemical markers, unipedal standing time (body balance), and five-repetition chair-rising time (muscle power) were evaluated. The duration of the study was 6 months. Ninety-six women who completed the trial were included in the subsequent analyses. At baseline, the age, body mass index, bone mass indices, bone turnover markers, unipedal standing time, and chair-rising time did not differ significantly between the two groups. During the 6-month treatment period, bone turnover markers decreased significantly from the baseline values similarly in the two groups. Although no significant improvement in the unipedal standing time was seen in the ED group, compared with the control group, the chair-rising time decreased significantly in the ED group compared with the control group. The present study showed that ED improved the chair-rising time in terms of muscle power in postmenopausal osteoporotic women treated with bisphosphonates. © 2014 Iwamoto and Sato. This work is published by Dove Medical Press Limited. Source


Iwamoto J.,Keio University | Sato Y.,Mitate Hospital
Expert Opinion on Pharmacotherapy | Year: 2013

Introduction: The effect of the anti-osteoporosis medicine, menatetrenone (vitamin K2; menaquinone-4) on the skeleton remains a matter of controversy. The objective of the present review study was to evaluate the effect of menatetrenone on the skeleton of postmenopausal women, men and glucocorticoid-treated patients. Methods: PubMed was used to search the literature for randomized controlled trials (RCTs), meta-analyses and systematic reviews. Thirteen RCTs, one meta-analysis and one systematic review were available for analysis. Results: Except for one large Japanese RCT (Phase IV trial: Osteoporotic Fracture (OF) study, n = 4378), RCTs with small sample size showed non-significant or modest effect on bone mineral density (BMD) in postmenopausal women and patients treated with glucocorticoid, positive effect on hip geometry in postmenopausal women and efficacy against fractures (mainly vertebral fractures) in postmenopausal women with osteoporosis. A post hoc analysis of the OF study showed that the incidence of vertebral fractures decreased in postmenopausal women with at least five vertebral fractures. A meta-analysis study, but not a systematic review study, showed efficacy against vertebral and non-vertebral fractures mainly in postmenopausal women with osteoporosis. There was no available evidence for men with osteoporosis. Conclusion: The present review of the literature revealed some evidence of a positive effect of menatetrenone on the skeleton of postmenopausal women and in patients treated with glucocorticoid. Expert opinion: Menatetrenone is considered to be a second-line medicine for postmenopausal osteoporotic women with an increased risk for vertebral fractures. © 2013 Informa UK, Ltd. Source


Sato Y.,Mitate Hospital | Iwamoto J.,Keio University | Honda Y.,Mitate Hospital
Journal of Neurology, Neurosurgery and Psychiatry | Year: 2011

Background: Incidence of a fracture, particularly in the hip joint, is high in Parkinson's disease (PD), owing to the immobilisation-induced bone resorption and vitamin D deficiency with reduced bone mineral density (BMD). The authors previously demonstrated the lowered incidence of hip fractures in PD by daily administration of risedronate and vitamin D. Methods: This randomised, double-blind, placebo-controlled study was conducted to determine the efficacy of 17.5 mg once-weekly risedronate in the prevention of hip fracture in women with PD. Patients were randomly assigned to 17.5 mg risedronate once a week (n=136) or a placebo (n=136) combined with daily 1000 IU of ergocalciferol. Incidence of hip fractures was compared between the two groups during the 2-year follow-up. Results: Hip fractures occurred in 15 patients in the placebo group and 3 patients in the risedronate group. The RR for hip fractures in the risedronate group as compared with the placebo group was 0.20 (95% CI 0.06 to 0.66). In the risedronate group, serum calcium levels decreased during the follow-up, while the levels in the placebo group increased. BMD increased by 3.4% in the risedronate group and decreased by 3.2% in the placebo group (p<0.01). Conclusions: Treatment with once-weekly risedronate and ergocalciferol prevents hip fractures in older women with PD. Source


Sato Y.,Mitate Hospital | Iwamoto J.,Keio University | Honda Y.,Mitate Hospital
Journal of Stroke and Cerebrovascular Diseases | Year: 2011

Although vitamin D supplementation has been suggested to reduce the risk of falling in ambulatory or institutionalized elderly persons, no study has examined whether it reduces the frequency of falling in immobilized stroke patients who have immobilization-induced hypercalcemia reflecting increased bone resorption leading to inhibited renal synthesis of 1, 25-dihydroxyvitamin D (1, 25-[OH]2D). Bisphosphonate is known to reduce immobilization-induced hypercalcemia by inhibiting bone resorption of calcium. This study compared the efficacy of 2 drugs in reducing the risk of falling in patients with long-standing stroke. Eighty-two elderly patients with poststroke hemiparesis were followed for 1 year. The patients were randomly assigned to one of 2 groups; 41 patients received alendronate 35 mg once weekly, and 41 patients received alphacalcidiol 1 μg daily. The number of falls per person and incidence of hip fracture in the 2 groups were compared. At baseline, all patients had a low serum 1, 25-[OH]2D level. Alphacalcidol therapy enhanced immobilization-induced hypercalcemia by increasing intestinal calcium absorption, leading to a reduction of serum 1, 25-[OH]2D level, while alendronate therapy enhanced 1, 25-[OH]2D production by decreasing hypercalcemia. Alendronate treatment accounted for a 55% reduction in falls (95% confidence interval [CI] = 25-72%; P = .0021). During the 1-year study period, hip fracture occurred in 1 of 41 subjects in the alphacalcidol group and in no subjects in the alendronate group. Bone mineral density was increased by 3.2% in the alendronate group and decreased by 0.1% in the alphacalcidol group (P < .0001). Alendronate therapy increased serum 1, 25-[OH]2D levels by improving immobilization-induced hypercalcemia, which may lead to decreased falling and subsequent hip fractures. © 2011 by National Stroke Association. Source

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