Increase in femoral bone mass by ipriflavone alone and in combination with 1α-hydroxyvitamin D3 in growing rats with skeletal unloading

We assessed the possibility that ipriflavone treatment might result in bone restoration in immobilized rats. We also investigated the effect of combined treatment with ipriflavone and vitamin D₃ on the bone. Male Sprague-Dawley rats, 6 weeks of age, were subjected to unilateral sciatic neurectomy. Three weeks after the operation, ipriflavone (100 mg/kg), 1α-hydroxyvitamin D₃ [1α(OH)D₃, 25 ng/kg], or both ipriflavone and 1α(OH)D₃ were orally administered every day for 12 or 24 weeks. After 12 weeks of treatment, only the group receiving combined treatment with ipriflavone and 1α(OH)D₃ showed increases in total femur calcium content (+16.4%, compared with the control). After 24 weeks, both animals treated with ipriflavone alone and those that had received the combination of ipriflavone and 1α(OH)D₃ showed significant increases in femur calcium content (+18.0% and +23.8%, respectively). In these treatment groups, X-ray analysis revealed an increase in bone mineral density over the entire length of the femur, and an increase in cortical diameter at the midshaft without affecting medullary width. Administration of 1α(OH)D₃ (25 ng/kg) alone had no effect. Body weight, femur length, and serum markers of calcium and bone metabolism were not affected in any group. We evaluated the relationship between ipriflavone and vitamin D₃ in bone cells in a culture system using rat bone marrow stromal cells in which the cells subsequently form mineralized bone-like tissue. Continuous treatment with ipriflavone (10⁻⁵ M) for 21 days resulted in an increase in osteocalcin secretion, and enhanced its response to 1α,25-dihydroxyvitamin D₃ (10⁻¹¹ M-10⁻⁸ M). These findings indicate that ipriflavone treatment increases the femoral bone mass in immobilized rats. In addition, a low dose of 1α(OH)D₃, which did not induce hypercalcemia, in combination with ipriflavone, augmented the stimulatory effect of ipriflavone alone on the bone mass, possibly due to a direct effect of each agent on osteoblastic cells.     

Effects of Ipriflavone on Bone Loss Following a Bilateral Ovariectomy and Menopause: A Randomized Placebo-Controlled Study

A randomized placebo controlled study was undertaken to evaluate the effect of ipriflavone (IP) against the bone loss in premenopausal ovariectomized women and postmenopausal women. Thirty-seven Japanese women who underwent premenopausal bilateral ovariectomy within 3 months (early stage group) and 52 Japanese women who were ovariectomized or who had undergone menopause more than 3 years before the start of the study (late stage group) were enrolled. The patients were randomly allocated into two groups: those who received IP (600 mg/day) and those who received placebo. The bone mineral density (BMD) of the lumbar vertebrae was measured by dual energy X-ray absorptiometry, and the markers of bone metabolism were measured at the same time that BMD was measured. In the early stage group, the IP group showed a 6.7% decrease in BMD from baseline levels, whereas the placebo group showed a 10.7% decrease (P < 0.01) at 12 months of treatment, and 7.1% and 12.6% decrease at 24 months of treatment, respectively (P < 0.01). In the late stage group, there was a 0.3% increase in BMD in the IP group and a 2.3% decrease in the placebo group at 6 months of treatment (P < 0.01), and similar changes were seen at 18 months (1.4% increase and 3.9% decrease; P < 0.01). IP suppressed bone loss compared with placebo, however, did not prevent acute bone loss in the early stage following ovariectomy. The effect of IP alone on bone loss in the early stage is not sufficient to reduce the risk of osteoporosis in later life.     

Effect of an Intermittent Weekly Dose of Human Parathyroid Hormone (1-34) on Osteoporosis: A Randomized Double-Masked Prospective Study Using Three Dose Levels

To test the effect of amino-terminal peptide 1–34 of human parathyroid hormone (hPTH (1–34)) as a possible bone anabolic agent in the treatment of osteoporosis, weekly subcutaneous injection of 50 units (L group), 100 units (M group) or 200 units (H group) of hPTH (1–34) was started in 220 patients with osteoporosis at 71 institutions randomly divided into three groups in a double-masked system. Lumbar spine bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) increased by 0.6%, 3.6% and 8.1% after 48 weeks in groups L, M and H respectively, responses in groups M and H being significantly higher than in L (p<0.05, Mann–Whitney U-test). Since the coefficient of variation for lumbar spine measurement stayed at 1–2.5%, increases of 3.6% and 8.1% appeared significant. Metacarpal BMD and cortical thickness measured by radiogrammetry did not change significantly. Serum calcium decreased in each group and serum phosphorus decreased in groups M and H. Urinary calcium/creatinine decreased at the 12th week in group H and at the 24th and 48th weeks in groups M and L. Serum 25(OH) vitamin D and 1,25(OH)₂ vitamin D decreased in each group at the 48th week (p<0.05). Serum bone-type alkaline phosphatase was increased at the fourth week in groups H and M and decreased at the 48th week in group H. Urinary hydroxyproline, pyridinoline and deoxypyridinoline declined significantly in each group. Backache improved in 30–40% of each group. No serious adverse effects were found during the test period. Intermittent weekly injection of hPTH (1–34) increased lumbar BMD in osteoporosis, suggesting usefulness in the treatment of osteoporosis. Received: 2 February 1998 / Accepted: 3 August 1998     

依普拉芬和雌激素对实验性骨质疏松作用的初步观察

目的：探讨依普拉芬和雌激素对绝经后骨质疏松症的防治作用。方法：将SD雌性大鼠32只随机分为4组,每组8只,I组：假手术组（Sham),Ⅱ组：切除卵巢组（OVX）,Ⅲ线：切除卵巢加雌激素组,Ⅳ组：切除卵巢加依普拉芬组。术后12周测定腰椎、股骨的骨密度：停药12周（即到术后24周）再行腰椎、股骨的骨密度测定及组织形态图像分析。结果：术后12周Ⅱ组大鼠体重增加明显与其他组差异有显性（P＜0.01),Ⅲ、Ⅳ两组之间无显性差异。术后24周Ⅲ、Ⅳ两组体重增加明显,与I组、Ⅱ组体重增加相比差异有显性（P＜0.05)。术后12周Ⅱ组腰椎、股骨骨密度下降明显,与Ⅲ、Ⅳ组差异有显性（P＜0.01);组织形态图像分析示Ⅳ组椎骨骨小梁面积增加,百分比增加,与Ⅱ组、Ⅲ组差异有显性（P＜0.001)。Ⅲ组、Ⅳ组股骨皮质骨厚度增加,骨小梁面积及百分比增加与Ⅱ组差异有显性（P＜0.001)。结论：依普拉芬和雌激素能有效地防止去势后大鼠的骨量丢失。依普拉芬有抑制骨吸收,又有促进骨形成的作用;其作用机理不同于雌激素。     

Ipriflavone prevents radial bone loss in postmenopausal women with low bone mass over 2 years

Two hundred and fifty-five postmenopausal women with distal forearm bone mineral density (BMD) 1 SD below the mean value for normal age-matched postmenopausal subjects were randomly allocated to a 2-year treatment with oral ipriflavone (200 mg t.i.d.) or a matched placebo, according to a double-masked, parallel-group design. All patients also received a 1 g/day calcium supplement. Distal radius BMD and bone metabolism markers were measured at baseline, and every 6 months. Blood haematology and chemistry and physical parameters were monitored at the same time. One hundred and ninety-six patients completed 2 years of treatment. BMD changes from baseline were analysed according to valid completers (VC) and intention to treat (ITT) analyses. In both cases radial BMD was maintained in patients treated with ipriflavone while it decreased in those receiving the placebo, the between-treatment difference being significant at year 1 and year 2. Urinary hydroxyproline/creatinine levels were decreased in the ipriflavone-treated group and increased in the placebo group, with a significant between-treatment difference. Adverse reactions, mainly gastrointestinal, occurred to a similar extent in the two treatment groups.In addition to the main investigators, the following authors were involved in the study: G. N. Castiglione², F. Gardini², G. Letizia⁴, L. Occhipinti⁵, N. Pardini⁵, M. Agamennone⁶, A. Sciolla⁷, A. Matucci⁸, R. Riboldi⁹, D. Costi¹⁰, E. Dall'Aglio¹⁰ and M. Pedrazzoni¹⁰     

Factors in response to treatment of early postmenopausal bone loss

Summary Bone mineral content (BMC) was measured by¹²⁵I photon absorptiometry every 3 months in 264 normal females (45–54 years) over a 2-year period together with serum samples for calcium, phosphate, magnesium, creatinine, alkaline phosphatases, potassium, and protein. A 48-h urinary calcium and creatinine measurement was obtained. The subjects were divided into 7 treatment groups and 3 placebo groups. Five of the treatments (thiazide, vitamin D₃, fluoride + vitamin D₃, fluoride, and 1αD₃) were ineffective at the doses used; the annual loss of compact bone was 1.5–2.2% (-X=1.8%), similar to the loss seen with placebos. Estrogen and estrogen + thiazide, in contrast, produced a 1.34% annual increase of BMC. The subjects were divided into groups with low, medium, and high initial BMC. Also, individual regressions for bone change were calculated and the subjects were divided into groups of responders, maintainers, and losers (annual change of >0%, 0 to −1%, and >−1%, respectively). The initial BMC status did not consistently affect bone or biochemical responses to the therapeutic agents. Estrogen was effective even in subjects with high BMC, whereas the other agents did not inhibit bone loss even in subjects with low initial BMC. Virtually all subjects responded to estrogen positively; in contrast we could not identify a subset of “responders” with any of the other treatments. Time since menopause appeared to influence the bone changes, although it was not a significant effect given the sample size. Bone loss in groups not treated with estrogens was 2%/year at 20 months after menopause with a decline to 1.3%/year at 45 months post-menopause. There was no apparent decline in the bone response to estrogen during the first 4 years after menopause, and in fact bone response tended to increase with time.     

Effects of cyclical etidronate therapy on bone loss in early postmenopausal women who are not undergoing hormonal replacement therapy

This study was carried out to investigate the effectiveness and tolerability of cyclical etidronate therapy in the prevention of bone loss occurring in early postmenopausal women who are not undergoing hormone replacement therapy (HRT). A total of 109 Caucasian women aged 45–60 years were treated with etidronate 400 mg/day or placebo for 14 days followed by calcium supplementation 500 mg/day for 77 days. Ninety-one women completed the 2 years of the study. After 2 years, the estimated difference between the two groups as regards lumbar spine bone mineral density (BMD) was 2.53% (SEM 1.07%;p=0.01); BMD of the hip and wrist were not significantly different between treatment groups. A clear reduction in bone turnover was obtained as evidenced by a significant decrease in serum alkaline phosphatase level and in urinary N-telopeptide/creatinine ratio in the etidronate group; the difference between the two groups was –12%±3.2% for serum alkaline phosphatase level (p=0.019) and –22.9%+13.7% for the urinary N-telopeptide/creatinine ratio (p=0.047). There was no statistically significant difference between the two groups in terms of the serum osteocalcin levels and urinary hydroxyproline/creatinine and calcium/creatinine ratios. Etidronate was generally well tolerated and its adverse event profile was similar to that of placebo. The results of this study indicate that cyclic etidronate therapy can prevent trabecular bone loss, with no deleterious effect on cortical bone, in the first 5 years of menopause and that it has a very high safety margin.     

依普拉芬对去卵巢大鼠骨质疏松骨保护效果及NO调控机制研究

目的 研究人工合成的植物雌激素-依普拉芬对去卵巢大鼠骨密度及生物力学的影响;同时与雌激素对照,探讨其骨保护效果及NO调控作用机制.方法 60只6月龄SD雌性大鼠,随机分成6组:假手术组和手术切除大鼠双侧卵巢组,后者分为阴性对照组、依普拉芬低、中、高剂量组和雌激素对照组, 分别给予基础饲料和不同剂量受试物,12周后进行骨密度、血清NO及NOS浓度测定;免疫组化方法检测股骨NOS表达.结果 与假手术组相比,去卵巢大鼠阴性对照组股骨密度、生物力学指标和血清NO、eNOS浓度以及股骨eNOS表达明显降低,血清iNOS浓度以及股骨iNOS表达增加,依普拉芬组骨密度、生物力学指标血清NO、eNOS浓度以及股骨eNOS表达均高于阴性对照组,与假手术组差异无显著意义.同时低于雌激素组.血清iNOS浓度以及股骨iNOS表达均低于阴性对照组,与假手术组以及雌激素组差异无显著意义.结论 一定浓度的依普拉芬可以通过提高去卵巢大鼠eNOS的表达来提高NO的浓度,促进成骨,增加骨密度,达到防治骨质疏松症的作用.     

Dietary Intake of Folate,but not Vitamin B<Subscript>2</Subscript> or B<Subscript>12</Subscript>, Is Associated with Increased Bone Mineral Density 5 Years after the Menopause: Results from a 10-Year Follow-Up Study in Early Postmenopausal Women

Folate, vitamin B₂ (riboflavin), and vitamin B₁₂ may affect bone directly or through an effect on plasma homocysteine levels. Previously, a positive association has been found between plasma levels and bone mineral density (BMD) as well as risk of fracture. However, there are limited data on whether dietary intakes affect bone. Our aim was to investigate whether intake of folate, vitamin B_2, and vitamin B₁₂, as assessed by food records affects BMD and fracture risk. In a population-based cohort including 1,869 perimenopausal women from the Danish Osteoporosis Prevention Study, associations between intakes and BMD were assessed at baseline and after 5 years of follow-up. Moreover, associations between intakes and 5- and 10-year changes in BMD as well as risk of fracture were studied. Intakes of folate, vitamin B₂, and vitamin B₁₂ were 417 (range 290–494) μg/day, 2.70 (range 1.70–3.16) mg/day, and 4.98 (range 3.83–6.62) μg/day, respectively, i.e., slightly above the intakes recommended by the United Nations Food and Agriculture Organization. At year 5, but not at baseline, cross-sectional analyses showed positive correlations between daily intake from diet and from diet plus supplements of folate and BMD at the femoral neck (P < 0.01). However, no associations were found between intakes and changes in BMD. During 10 years of follow-up, 360 subjects sustained a fracture. Compared with 1,440 controls, logistic regression analyses revealed no difference in intakes between cases and controls. A high dietary intake of folate, but not vitamin B₂ or B₁₂, exerts positive effects on BMD; but further studies are needed to confirm this association.     

Comparison of effects of estriol on bone mineral density of vertebrae between elderly and postmenopausal women

To compare the efficacy of estriol (E₃) for postmenopausal and senile osteoporosis, we administered orally 1 g/day calcium lactate alone (control groups) or with 2 mg/day estriol (E₃ groups) to 20 postmenopausal women aged 50–65 years and 29 elderly women aged 70–84 years, and determined their bone mineral density (BMD) of the lumbar vertebrae AP scan by dual-energy X-ray absorptiometory. Of 41 subjects who completed 10 months of treatment, 8 postmenopausal women and 12 elderly women in the E₃ groups showed a significant (P < .05) increase in BMD, 5.59% ± 4.79% and 3.83% ± 7.90% of the respective basal values, while 10 postmenopausal women and 11 elderly women in the control groups showed a decrease in BMD, −4.02% ± 7.00% and −3.26% ± 4.60% of the respective basal values, after 10 months. On the other hand, genital bleeding as a side effect of E₃ occurred in 6 elderly subjects at this dose. Moreover, decrease in serum level of corrected calcium was seen only in the elderly women receiving E₃. Although a lower dosage of E₃ may be recommended for elderly subjects, these observations suggest, first, that hormone replacement therapy with E₃ has efficacy for involutional osteoporosis, and, second, that the bones in elderly women also maintain responsiveness to E₃. Received: May 19, 1997 / Accepted: July 7, 1997     

The influence of ipriflavone on bone metabolism and reduction of bone mineral density decrease by ipriflavone following menopause or bilateral oophorectomy

A total of 22 female patients under age 60 who showed a decrease in bone mineral density (BMD) after menopause and/or bilateral oophorectomy received 600 mg/day ipriflavone (IP) for 1 year, and the effects on bone metabolism and BMD were observed. Although estrogen levels were low in these patients, a significant rise in serum calcitonin and a decrease in serum calcium were observed. Osteocalcin, a bone formation indicator, also showed a significant increase. These findings suggest IP both inhibits bone resorption and promtes bone formation not only in vitro but also in vivo. BMD of cancellous bone was measured using quantitative computed tomography (QCT). Cancellous bone is believed to most sensitively reflect changes in bone metabolism because of its high rate of metabolic turnover [1]. The patients who had not received IP showed a significant decrease in BMD, while those who had received IP showed only a slight decrease. These observations suggest that IP can be used successfully to reduce the rapid decrease in bone density associated with menopause and/or bilateral oophorectomy.     

Monitoring estrogen replacement therapy and identifying rapid bone losers with an immunoassay for deoxypyridinoline

We have assessed urinary deoxypyridinoline (Dpd) levels by immunoassay in women who participated in a double-masked, placebo-controlled trial of the bone loss prevention effects of estrogen replacement therapy (ERT). Ninety-one women who had undergone recent surgical menopause were randomdized to receive either placebo or 0.025, 0.05 or 0.1 mg/day transdermal 17β-estradiol for 2 years. Mean Dpd levels in the postmenopausal women were significantly elevated (p<0.0001) above mean Dpd levels in a reference population of healthy, premenopausal women. Subjects in the placebo group lost 6.4% of lumbar spine bone mineral density (BMD) and 4.9% of mid-radius bone mineral content (BMC) over 2 years. Dpd levels at baseline were inversely correlated with BMD and BMC changes in the placebo group. The placebo group and subjects receiving 0.025 mg/day 17β-estradiol who had Dpd levels increased above the reference interval cut-off (mean + 2 standard deviations, 7.5 nmol/mmol) lost 2 times more bone mass than did those with Dpd levels below it. Dpd levels decreased significantly (p<0.01) from baseline at 6 months following initiation of treatment with 0.05 or 0.1 mg/day 17β-estradiol, changes that correlated with increased lumbar spine BMD and with changes in mid-radius BMC. At 12 months, Dpd levels were lower than baseline and placebo in all three treatment groups. These data suggest utility of this Dpd immunoassay in assessing changes in bone resorption induced by surgical menopause and ERT.     

Image-Based Assessment of Spinal Trabecular Bone Structure from High-Resolution CT Images

The goal of this study was to assess whether a high-resolution CT measure of trabecular bone structure can enhance the discrimination between subjects with or without a vertebral fracture and having overall low hip or spine bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Sixty-one women with low BMD by DXA (T-score <–2.5 at hip or spine) were examined. Twenty women had sustained a vertebral fracture. Quantitative CT (QCT) BMD and high-resolution CT spinal scans were performed on a whole-body CT scanner. For the high-resolution images (0.31 mm pixel, 1.5 mm thick slice), trabecular bone was segmented from marrow using an adaptive threshold, region growth and skeletonization step. From the processed image we measured the apparent trabecular bone fraction (BV/TV), apparent trabecular thickness (I.Th) and apparent trabecular spacing (I.Sp). We also assessed the connectivity of the marrow space using region growing to derive a mean (H_A) and maximum (H_M) hole size. Despite the fact that the study population was preselected to have a low BMD by DXA, QCT BMD was highly associated with (p <0.005) with fracture status. All structural parameters were correlated (r ~ 0.64 to 0.79) with BMD with p <0.003 and showed significant differences between the fracture and non-fracture group. However, except for H_A, this difference did not remain significant after adjustment for BMD. When BMD and then H_A was entered into a paired linear regression model to predict fracture outcome, H_A contributed with p= 0.03 and BMD with p= 0.86. ROC analysis was applied and showed that H_A, BMD, I.Th and I.Sp discriminated the two groups with areas of 0.76, 0.75, 0.71 and 0.68, respectively. These findings suggest that an assessment of vertebral trabecular structure from high-resolution CT images is useful in discriminating subjects with vertebral fractures and potentially useful for predicting future fractures. Received: 10 October 1997 / Accepted: 4 December 1997     

Effect of combined administration of vitamin D3 and vitamin K2 on bone mineral density of the lumbar spine in postmenopausal women with osteoporosis

The effect of the combined administration of vitamin D₃ and vitamin K₂ on bone mineral density (BMD) of the lumbar spine was examined in postmenopausal women with osteoporosis. Ninety-two osteoporotic women who were more than 5 years after menopause, aged 55–81 years, were randomly divided into four administration groups: vitamin D₃ (1α hydroxyvitamin D₃, 0.75 μg/day) (D group; n = 29), vitamin K₂ (menatetrenone, 45 mg/day) (K group; n = 22), vitamin D₃ plus vitamin K₂ (DK group, n = 21), and calcium (calcium lactate, 2 g/day) (C group; n = 20). BMD of the lumbar spine (L2–L4) was measured by dual energy X-ray absorptiometry at 0, 1, and 2 years after the treatment started. There were no significant differences in age, body mass index, years since menopause, and initial BMD among the four groups. One-way analysis of variance (ANOVA) with repeated measurements showed a significant decrease in BMD in the C group (P < 0.001). Two-way ANOVA with repeated measurements showed a significant increase in BMD in the D and K groups compared with that in the C group (P < 0.05 and P < 0.001, respectively), and a significant increase in BMD in the DK group compared with that in the C, D, and K groups (P < 0.0001, P < 0.05 and P < 0.01, respectively). These findings indicate that combined administration of vitamin D₃ and vitamin K₂, compared with calcium administration, appears to be useful in increasing the BMD of the lumbar spine in postmenopausal women with osteoporosis. Received: January 13, 2000 / Accepted: June 5, 2000     

Comparison of antiresorptive activities of ipriflavone, an isoflavone derivative, and elcatonin, an eel carbocalcitonin

Thirty postmenopausal women with reduced bone mineral density were divided randomly into two groups based on the chronological sequence of their first visit to the Osteoporosis Clinic of Katsuragi Hospital. Group I was given 600 mg ipriflavone orally daily and group II was weekly injected intramuscularly with 20 units elcatonin, Asu^1–7 eel calcitonin (carbocalcitonin). Lumbar spine BMD was measured by dual-energy X-ray absorptiometry, and trabecular bone mineral density at the distal radius, cortical bone density, and relative cortical volume at the radial diaphysis by peripheral computed tomography before the beginning of the study and at the 4th, 8th, and 12th month. Markers of bone metabolism—serum total alkaline phosphatase, bone-specific alkaline phosphatase, tartrate-resistant acid phosphatase, osteocalcin, intact osteocalcin, PICP and ICTP, and urinary pyridinoline, deoxypyridinoline, and calcium/creatinine (Ca/Cr)—were also measured at the same interval. Plasma parathyroid hormone (PTH) and calcitonin (CT) were measured at the same time. Radial trabecular bone density showed a significantly higher rate of increase in group I (ipriflavone group) than in group II (elcatonin group) at the 4th month, whereas lumbar spine BMD showed more pronounced increase in the elcatonin group than in the ipriflavone group throughout the study period. Bone metabolism markers tended to decline in both groups. Total and intact osteocalcin showed a significant fall from the baseline throughout the study period only in the ipriflavone group. Urine pyridinoline and deoxypyridinoline showed a significant fall from the baseline at the 12th month only in the ipriflavone group. On comparing bone gainers with increase of lumbar spine BMD by 2% or more with bone losers with a decrease by 2% or more, only urine Ca/Cr was significantly different, lower in the former than in the latter, despite the general tendency for bone resorption markers to decrease in bone gainers and to increase in bone losers. Received: Jan. 13, 1999 / Accepted: Feb. 26, 1999     

CT引导下经皮肺穿刺活检诊断肺部磨玻璃样病变

目的评价CT引导下经皮肺穿刺活检(PTNB)诊断肺部恶性磨玻璃样病变(GGO)的价值。方法回顾性分析60例因肺部GGO而于我院接受CT引导下PTNB患者的临床资料。根据针道距离,分为A_1(5 cm,n=28)、B_1(5~9 cm,n=18)、C_1(9 cm,n=14)组;根据GGO在肺内的百分比,分为A_2(50%~90%,n=32)、B_2(90%,n=28)组。计算CT引导下PTNB诊断各组肺部恶性GGO的效能并比较其效能差异。结果 CT引导下PTNB诊断肺部恶性GGO的敏感度、特异度及准确率分别为87.50%(42/48)、100%(12/12)、90.00%(54/60)。对于A_1、B_1、C_1组及A_2、B_2组,其诊断效能差异均无统计学意义(P均0.05)。结论 CT引导下PTNB诊断肺部恶性GGO具有较高的敏感度、特异度和准确率,且其诊断效能与针道距离及GGO在肺内的百分比无关。     

Effect of prostaglandin D2 on the femoral bone mineral density in ovariectomized rats

Summary We studied the effects of prostaglandin D₂ (PGD₂) on the femoral bone mineral density (BMD) and other related parameters in ovariectomized (OVx) and shamoperated rats. BMD was measuredin vivo by dual energy X-ray absorptiometry (DXA) for the period of 36 days or 112 days after operation. When 9- or 10-week-old rats were used at the time of operation, the femoral BMD increased during these periods. Ovariectomy resulted in a marked suppression of this steady increase in BMD at both proximal and distal ends of the femur. Subcutaneous administration of a slow-release preparation of PGD₂ on days 1 and 21 not only prevented the ovariectomy-induced suppression of BMD, but also augmented the steady increase in BMD of the shamoperated rats. When medication was started on day 70, the depressed rate of increase in BMD was restored to the control level. Serum calcitonin (CT) and parathyroid hormone (PTH) levels were not affected by either ovariectomy or by PGD₂ administration. Body weight and bone length were increased, but uterine weight was decreased by ovariectomy. PGD₂ administration showed no effects on these parameters. There was a significant increase in the fasting level of urinary hydroxyproline excretion after ovariectomy, and PGD₂ administration had no significant effect on this parameter either. These results indicate that the prevention of osteopenia in OVx rats and the increase in BMD in shamoperated and post-OVx rats by PGD₂ administration are due to its stimulatory effect on bone formation.     

The Association of Bone Mineral Density with Vitamin D Receptor Gene Polymorphisms

A recent meta-analysis of 16 publications suggested that bone mineral density (BMD) is not associated with vitamin D receptor (VDR) gene polymorphism (VDRGP) at the 0.05 significance level when a study with genotyping mistakes is excluded. We wished to determine whether ‘positive’ findings supporting the BMD–VDRGP association may be explained by chance, and what factors affect the outcomes of these studies. Seventy-five articles and abstracts on the association of VDRGP with BMD and related skeletal phenotypes published before January 1997 were identified. Twenty-three of 67 (34.3%) studies on spinal BMD and 22 of 51 (43.1%) on femoral neck BMD had found a BMD–VDRGP association at p<0.05, significantly (p= 7 × 10^–14 for spinal BMD, p= 9 × 10^–16 for hip BMD) higher than the expected 5% false positive rate under the null hypothesis of ‘no association’. ‘Positive’ results were more frequently observed in studies on females before the menopause than those on females after the menopause (p<0.02) or on male and female subjects combined (p<0.05) when skeletal phenotypes at any bone sites were considered. The ‘positive rate’ among studies was also influenced by the age range of subjects studied and by the inclusion of subjects with osteoporosis. It is concluded that: (1) BMD is associated with VDRGP with high levels of confidence and (2) non-genetic factors and genetic heterogeneity interfere with the detection of the effects of VDRGP on bone phenotypes. Received: 20 January 1998 / Accepted: 7 April 1998     

Early Postmenopausal Bone Loss is Prevented by Estrogen and Partially by 1α-OH-vitamin D3: Therapeutic Effects of Estrogen and/or 1α-OH-vitamin D3

A total of 79 Japanese women who were within 5 years of menopause were randomly assigned 1α-hydroxyvitamin D₃ [1α(OH)D₃] 1.0 μg/day, conjugated estrogens 0.625 mg/day, a combination of both, or control (no treatment). Lumbar spine and proximal femur bone mineral density (BMD) and biochemical indices were monitored over 2 years. In the 1α(OH)D₃-treated group, there was a nonsignificant decrease in lumbar spine BMD compared with controls, and no significant loss in the femoral neck compared with controls. In the estrogen-treated group, there was a nonsignificant increase in spine BMD (+2.17% in the first year and +1.71% in the second year), and no loss in femoral neck BMD. The combination of conjugated estrogens +1α(OH)D₃ was more effective in increasing BMD in the spine (+3.68% in the first year and +3.63% in the second year) and femur (+2.56% in the first year and +4.44% in the second year) BMD. There was a significant difference in lumbar spine BMD in both the first and second years between the combination-treated group and the 1α(OH)D₃-treated and control groups (P < 0.01). Serum osteocalcin (OC) significantly decreased in the combination-treated group (−23.8% in the first year) and the estrogen-treated group (−37.6% and −41.2% at 6 and 18 months, respectively), and serum alkaline phosphatase (Alp) decreased significantly in the first year in the combination-treated (−31.5%), estrogen-treated (−27.3%), and 1α(OH)D₃-treated (−7.9%) groups, whereas serum OC increased (+45.4% in the first year) in women without treatment. The results of this study indicate that early postmenopausal bone loss in the femoral neck is prevented by conjugated estrogens, 1α(OH)D₃, or both, whereas bone loss in the spine is not prevented by 1α(OH)D₃. Estrogen proves effective in preventing early postmenopausal bone loss by markedly inhibiting bone turnover. Moreover, a synergistic bone-sparing effect can be expected when estrogen is administered concomitantly with 1α(OH)D₃ rather than when used alone. Received: 28 April 1998 / Accepted: 23 December 1998     

VDR Genotype and Response to Etidronate Therapy in Late Postmenopausal Women

Twenty-four late postmenopausal women with osteoporosis were studied. The patients were separated in three subgroups according to the BsmI polymorphism of the vitamin D receptor (VDR) gene: BB (n= 8), Bb (n = 10) and bb (n = 6). They did not differ in age (mean ages were 66.0 years, 65.9 years and 63.9 years, respectively), years after menopause (18.7 years, 18.1 years and 18.4 years) or body weight (64.9 kg, 65.3 kg and 63.8 kg), the variables known to be associated with bone mineral density (BMD). The results show that the response to antiresorptive bisphosphonate therapy in combination with calcium supplementation is modified by VDR genotype. The lumbar spine BMD increased significantly faster in the BB and Bb groups (7.3% and 7.0%, respectively) compared with the bb group (2.5%) during 1 year of cyclic etidronate therapy (400 mg/day) and calcium supplementation (1000 mg/day). The biochemical marker of bone resorption (urinary hydroxyproline excretion) as well as the bone formation marker (serum levels of osteocalcin) decreased during the treatment. With respect to VDR genotype, a significantly higher decrease in osteocalcin level was observed in bb as compared with BB subjects. We conclude that the VDR genotype is involved in an individual’s response to cyclic etidronate therapy with calcium supplementation. Received: 12 December 1998 / Accepted: 18 March 1999