The effects of combined human parathyroid hormone (1-34) and zoledronic acid treatment on fracture healing in osteoporotic rats

Summary  

Ovariectomized (OVX) rats with tibial fracture received vehicle, ZA, PTH, or ZA plus PTH treatment for 4 and 8 weeks. Bone metabolism, callus formation, and the mass of undisturbed bone tissue were evaluated by serum analysis, histology, immunohistochemistry, radiography, micro-computerized tomography, and biomechanical test.     

甲状旁腺激素（1-34）与唑来膦酸联合治疗对骨质疏松大鼠骨折愈合的影响

目的探讨唑来膦酸(ZA)与甲状旁腺激素(PTH)的联合应用对去势大鼠骨折愈合的影响。方法对双侧卵巢摘除术12周后的大鼠行单侧胫骨水平骨切开术,并以髓内钉进行固定。所有大鼠在行骨折造模术后,随机接受赋形剂、ZA、PTH与ZA+PTH治疗。在治疗4或8周后,收集胫骨标本进行micro-CT、组织学及生物力学测试。结果与对照组相比,所有药物干预方法都促进了骨痂形成、增加了骨痂强度;ZA+PTH组在相对骨体积(BV/TV)、骨小梁粗度和生物力学上表现出了最强的促进作用。结论 ZA与PTH联合应用对去势大鼠的骨折愈合有累加作用。     

Early effect of parathyroid hormone (1-34) on implant fixation.

Intermittent systemic administration of parathyroid hormone increases bone formation by stimulating osteoblastic activity. The current study determined how parathyroid hormone (1-34) administration influences the bony fixation of stainless steel screws with time. A screw was implanted in the left tibia and a metal rod was implanted in the right tibia in 30 adult male rats that then were injected three times a week with human parathyroid hormone (1-34) at 60 microg/kg/injection (n = 15) or saline (n = 15). The animals were euthanized after 1, 2, or 4 weeks of treatment. Eight additional rats received only the screw and were euthanized immediately after implantation. No significant effects of parathyroid hormone on body weight change or ash weight of the femurs were seen. The degree of fixation was assessed by measuring pullout strength of the screws. The mean pullout strength immediately after implantation was 12 N. The pullout strength of the group injected with saline was 33 N after 1 week, 23 N after 2 weeks, and 41 N after 4 weeks. The pullout strength of the group injected with parathyroid hormone increased to 43 N after 1 week, 58 N after 2 weeks, and 100 N after 4 weeks. The increase at 2 and 4 weeks was statistically significant. Strength reflects the mechanical properties of the bone within the screw threads. The contralateral tibia with its metal rod was used for blinded histologic assessment. Parathyroid hormone increased the fraction of the metal surface having contract with bone without an intervening soft tissue layer from 45% to 69% after 1 week. The current results suggest that intermittent parathyroid hormone treatment can enhance early implant fixation by enhancing the density of the surrounding bone and by increasing the implant bone contact.     

Combined effects of recombinant human BMP-7 (rhBMP-7) and parathyroid hormone (1-34) in metaphyseal bone healing

Fracture healing involves multiple stages of repair and coordinated actions of multiple cell types. Consequently, it may be possible to enhance healing through treatment strategies that target more than one repair process or cell type. The goal of this study was to determine the combined effects of recombinant human bone morphogenetic protein 7 (rhBMP-7) and parathyroid hormone (PTH(1-34)) on metaphyseal bone healing. A wedge-shaped defect was created in the lateral aspect of the distal tibia in female New Zealand white rabbits (n=64) and was filled with tricalcium phosphate (TCP). Animals were assigned to four groups: 1) BMP-7 and PTH; 2) BMP-7; 3) PTH; and 4) control (TCP alone). In groups 1 and 2, 200 microg rhBMP-7 was incorporated into the TCP. Animals received daily subcutaneous injections of 10 microg/kg PTH(1-34) (groups 1 and 3) or saline (groups 2 and 4). Healing at 4 weeks was assessed using micro-computed tomography, histology, immunohistochemistry, and mechanical testing. Combined treatment with rhBMP-7 and PTH resulted in increased callus total volume (TV), mineralized volume (BV), average cross-sectional area, and bone mineral content (BMC) as compared to the control group (p<0.02). BV and BMC were also higher in the combined treatment group as compared to the BMP-7 group (p<0.02); however, tissue mineral density was highest in the BMP-7 group (p=0.002). New bone formation in the BMP-7 group was largely restricted to the defect site, while PTH promoted bone formation throughout the defect and surrounding regions. Combined treatment led to greater quantities of woven trabecular bone, increased trabecular thickness, decreased trabecular separation (p<0.04), and a trend towards increased numbers of osteoclasts (p=0.09). Combined treatment also resulted in increased torsional rigidity and compressive strength as compared to the control and BMP-7 groups (p<0.001). These results suggest that the improvements in mechanical function obtained with the combined treatment resulted from differing biological activities of rhBMP-7 and PTH. While the activities of rhBMP-7 appeared to be strictly anabolic, those of PTH appeared to work in the context of coupled remodeling. The combination of both agents led to greater bone volume as well as better microstructural organization and integration of this bone with the surrounding tissues.     

甲状旁腺激素（1-34)、雷奈酸锶、唑来膦酸对绝经后骨质疏松症的疗效对比研究

目的比较甲状旁腺激素(1-34)(PTH)、雷奈酸锶(SR)、唑来膦酸(ZA)对绝经后妇女骨质疏松的疗效。方法 150例绝经后骨质疏松症患者被随机分为三组:PTH组、SR组和ZA组,进行开放、对比研究。SR组每天口服雷奈酸锶2 g/d;PTH组每天皮下注射20μg的PTH(1-34);ZA组给予唑来膦酸5 mg静脉滴注。治疗前、后6个月及1年分别测定两组患者腰背部自发性疼痛的VAS评分、L_(1-4)椎体、股骨颈、Wards三角的BMD值,并观察治疗期间三组骨质疏松性骨折的发生率及服药后的不良反应。结果治疗后PTH组和SR组VAS评分明显改善,低于ZA组;PTH组L_(1-4)椎体、股骨颈、Wards三角的BMD值在治疗后6月及12月较治疗前上升显著,明显优于SR组及ZA组(P0.05)。骨质疏松脆性骨折的发生率PTH组低于SR组及ZA组。三组药品不良反应发生率比较,差异无统计学意义(P0.05)。结论 PTH、SR和ZA都可以有效降低VAS评分,提高骨密度,降低骨质疏松脆性骨折的发生率,且药物副反应少,其中以PTH效果最佳。     

Enhancement of graft bone healing by intermittent administration of human parathyroid hormone (1-34) in a rat spinal arthrodesis model

Bone grafting is commonly used to treat skeletal disorders associated with large bone defect or unstable joint. It can take several months, however, to achieve a solid union and bony fusion sometimes delays or fails especially in osteoporosis patients. Therefore, we used a rat spinal arthrodesis model to examine whether intermittent administration of human PTH(1-34) accelerates bone graft healing. Eighty-two male Sprague-Dawley rats underwent posterolateral spinal arthrodesis surgery using autologous bone grafts. Animals were given daily subcutaneous injections of hPTH(1-34) (40 microg/kg/day PTH group) or 0.9% saline vehicle (control group) from immediately after surgery till death. Five rats each were killed 2, 4, 7, and 14 days after the surgery, and mRNA expression analysis was performed on harvested grafted bone. Seven rats each were killed 14, 28, and 42 days after the surgery, and the lumbar spine, which contained the grafted spinal segment, was subjected to fusion assessment, microstructural analysis using three-dimensional micro-computed tomography, and histologic examination. Serum bone metabolism markers were analyzed. The results indicated that PTH administration decreased the time required for graft bone healing and provided a structurally superior fusion mass in the rat spinal arthrodesis model. PTH administration increased the fusion rate on day 14 (14% in the control group and 57% in the PTH group), accelerated grafted bone resorption, and produced a larger and denser fusion mass compared to control. mRNA expression of both osteoblast- and osteoclast-related genes was upregulated by PTH treatment, and serum bone formation and resorption marker levels were higher in the PTH group than in the control group. Histologically calculated mineral apposition rate, mineralized surface and osteoclast surface were also higher in the PTH group than in the control group. These findings suggest that intermittent administration of PTH(1-34) enhanced bone turn over dominantly on bone formation at the graft site, leading to the acceleration of the spinal fusion. Based on the results of this study, intermittent injection of hPTH(1-34) might be an efficient adjuvant intervention in spinal arthrodesis surgery and all other skeletal reconstruction surgeries requiring bone grafts.     

Anabolic and catabolic bone effects of human parathyroid hormone (1-34) are predicted by duration of hormone exposure

Parathyroid hormone (PTH)(1-34), given once daily, increases bone mass in a variety of animal models and humans with osteoporosis. However, continuous PTH infusion has been shown to cause bone loss. To determine the pharmacokinetic profile of PTH(1-34) associated with anabolic and catabolic bone responses, PTH(1-34) pharmacokinetic and serum biochemical profiles were evaluated in young male rats using dosing regimens that resulted in either gain or loss of bone mass. Once-daily PTH(1-34) or 6 PTH(1-34) injections within 1 h, for a total daily dose of 80 microg/kg, induced equivalent increases in proximal tibia bone mass. In contrast, 6 PTH(1-34) injections/day over 6 h for a total dose of 80 microg/kg/day or 3 injections/day over 8 h for a total of 240 microg/kg/day decreased tibia bone mass. The PTH(1-34) pharmacokinetics of the different treatment regimens were distinctive. The magnitude of the maximum serum concentrations (Cmax) of PTH(1-34) and area under the curve (AUC) did not predict the catabolic bone outcome. Compared to the anabolic pharmacokinetic profile of a transient increase in PTH(1-34) with rapid decreases in serum calcium and phosphate, the catabolic regimen was associated with PTH(1-34) concentrations remaining above baseline values during the entire 6-h dosing period with a trend toward an increase in serum calcium and a prolonged decrease in phosphate. The pharmacokinetic profiles suggest that the anabolic or catabolic response of bone to PTH(1-34) is determined primarily by the length of time each day that serum concentrations of PTH(1-34) remain above baseline levels of endogenous PTH and only secondarily by the Cmax or AUC of PTH(1-34) achieved.     

Comparison of bone formation responses to parathyroid hormone(1-34), (1-31), and (2-34) in mice

In this study we used a mouse model system to compare the in vivo effects of parathyroid hormone(1-34) [PTH(1-34)] with that of PTH(1-31) or PTH(2-34) analogs. Daily subcutaneous administration of PTH(1-34) for 15 days caused a dose-dependent increase in the serum osteocalcin level and bone extract alkaline phosphatase activity, markers of bone formation. PTH(2-34) was much less potent, whereas PTH(1-31) was equipotent in stimulating bone formation parameters in mice. PTH(1-34) caused significant increases in serum calcium (after 4 h) and tartrate-resistant acid phosphatase activity in bone extract (after 4 h), whereas PTH(2-34) and PTH(1-31) were less potent. Because PTH(1-31) caused a smaller increase in bone resorption parameters compared to PTH(1-34), despite similar effects on bone formation parameters, we evaluated the long-term anabolic effects of PTH(1-31) and PTH(1-34) in mice. Weekly evaluations of serum osteocalcin levels demonstrated that daily injections of PTH(1-34) and PTH(1-31) at 80 microg/kg body weight increased serum osteocalcin levels within 1 week of the start of treatment, which were maintained during the entire 22 week treatment. Assessment of bone density at the end of the treatment period with peripheral quantitated computed tomography (pQCT) revealed that PTH(1-34) caused a significantly greater increase in femoral bone density compared to PTH(1-31) at the middiaphysis (18% vs. 9% over vehicle control; p < 0.001). Both PTH(1-34) and PTH(1-31) increased periosteal circumference compared to vehicle (p < 0.01) without a significant difference between the two treatments. In contrast, PTH(1-34) caused a significantly greater reduction in endosteal circumference than PTH(1-31) (p < 0.001). Both analogs significantly increased maximum load and area of moment of inertia over the vehicle group. In conclusion, our findings suggest that PTH(1-34) and PTH(1-31) may exhibit different anabolic effects at the periosteum vs. endosteum in the long bones of mice.     

Intermittent parathyroid hormone (1-34) treatment increases callus formation and mechanical strength of healing rat fractures.

The influence of intermittent parathyroid hormone (PTH(1-34)) administration on callus formation and mechanical strength of tibial fractures in rats was investigated after 20 and 40 days of healing. A dose of 60 microg of PTH(1-34)/kg/day and 200 microg of PTH(1-34)/kg/day, respectively, was administered during the entire periods of healing, and control animals with fractures were given vehicle. The dose of 200 microg of PTH(1-34)/kg/day increased the ultimate load and the external callus volume of the fractures by 75% and 99%, respectively, after 20 days of healing and by 175% and 72%, respectively, after 40 days of healing. The dose of 60 microg of PTH(1-34)/kg/day did not influence either ultimate load or external callus volume of the fractures after 20 days of healing, but the ultimate load was increased by 132% and the external callus volume was increased by 42% after 40 days of healing. During the healing period, the callus bone mineral content (BMC) increased in all groups. After 40 days of healing, the callus BMC was increased by 108% in the 200 microg of PTH(1-34)/kg/day group and by 76% in the 60 microg of PTH(1-34)/kg/day group. Both doses of PTH(1-34) steadily augmented the contralateral intact tibia BMC (20 days and 40 days: 60 microg of PTH (1-34)/kg/day 9% and 19%, respectively; 200 microg of PTH (1-34)/kg/day 12% and 27%, respectively) and bone mineral density (20 days and 40 days: 60 microg of PTH(1-34)/kg/day 11% and 12%, respectively; 200 microg of PTH(1-34)/kg/day 11% and 15%, respectively).     

Intermittently administered human parathyroid hormone(1-34) treatment increases intracortical bone turnover and porosity without reducing bone strength in the humerus of ovariectomized cynomolgus monkeys.

Cortical porosity in patients with hyperparathyroidism has raised the concern that intermittent parathyroid hormone (PTH) given to treat osteoporotic patients may weaken cortical bone by increasing its porosity. We hypothesized that treatment of ovariectomized (OVX) cynomolgus monkeys for up to 18 months with recombinant human PTH(1-34) [hPTH(1-34)] LY333334 would significantly increase porosity in the midshaft of the humerus but would not have a significant effect on the strength or stiffness of the humerus. We also hypothesized that withdrawal of PTH for 6 months after a 12-month treatment period would return porosity to control OVX values. OVX female cynomolgus monkeys were given once daily subcutaneous (sc) injections of recombinant hPTH(1-34) LY333334 at 1.0 microg/kg (PTH1), 5.0 microg/kg (PTH5), or 0.1 ml/kg per day of phosphate-buffered saline (OVX). Sham OVX animals (sham) were also given vehicle. After 12 months, PTH treatment was withdrawn from half of the monkeys in each treatment group (PTH1-W and PTH5-W), and they were treated for the remaining 6 months with vehicle. Double calcein labels were given before death at 18 months. After death, static and dynamic histomorphometric measurements were made intracortically and on periosteal and endocortical surfaces of sections from the middiaphysis of the left humerus. Bone mechanical properties were measured in the right humeral middiaphysis. PTH dose dependently increased intracortical porosity. However, the increased porosity did not have a significant detrimental effect on the mechanical properties of the bone. Most porosity was concentrated near the endocortical surface where its mechanical effect is small. In PTH5 monkeys, cortical area (Ct.Ar) and cortical thickness (Ct.Th) increased because of a significantly increased endocortical mineralizing surface. After withdrawal of treatment, porosity in PTH1-W animals declined to sham values, but porosity in PTH5-W animals remained significantly elevated compared with OVX and sham. We conclude that intermittently administered PTH(1-34) increases intracortical porosity in a dose-dependent manner but does not reduce the strength or stiffness of cortical bone.     

国产重组人甲状旁腺素(1-34)对绝经后骨质疏松症的治疗作用研究

目的评价国产重组人甲状旁腺素(1-34)治疗绝经后骨质疏松症的临床疗效和安全性。方法入选绝经后骨质疏松症患者37例,年龄64.2±8.1岁,采用自身前后对照试验设计,每日皮下注射重组人甲状旁腺素(1-34)20μg,同时口服钙尔奇D600 0.6g/d,试验时间6个月,观察患者治疗前后骨密度变化、骨折发生情况,以及血尿常规、肝肾功、电解质、心电图改变等。结果试验期间有1例脱落;经过6个月治疗后,患者L1骨密度增加23.2%(P<0.05),L2骨密度增加18.0%(P<0.05),L3骨密度增加12.5%(P<0.05),L4骨密度增加19.9%(P<0.05),腰椎平均骨密度增加17.8%(P<0.05),股骨颈骨密度增加2.2%(P>0.05),大粗隆骨密度降低6.0%(P>0.05),Wards区骨密度降低1.3%(P>0.05);试验期间新发骨折2例,1例右肱骨骨折,另1例腰椎压缩骨折,无其他严重不良事件发生。结论重组人甲状旁腺素(1-34)治疗绝经后骨质疏松症有效,对腰椎骨密度改善显著,不良反应较轻。     

甲状旁腺素（1-34)对去卵巢大鼠掺锶羟基磷灰石涂层植体骨整合的影响

目的 探索甲状旁腺素（1 -34)对去卵巢大鼠掺锶羟基磷灰石涂层种植体骨整合的影响。方法行双侧卵巢摘除术后12 w,大鼠随机分为Control组、PTH组、Sr组及PTH + Sr组,之后分别在双侧股骨植人羟基磷灰石或掺锶羟基磷灰石涂层的钛钉,PTH组及PTH + Sr组术后给予PTH治疗。12 w后处死大鼠取双侧行Micro-CT、组织学及生物力学检测。结果 Micro-CT三维重建显示,PTH + Sr组钛棒周围有最多的骨组织形成,微观参数定量结果表明与Control组相比,PTH +Sr组骨体积分数BV/TV增加了 2. 45倍,骨小梁数量（Tb.N)增加了2. 94倍,骨小梁连接密度（Conn. D)增加了 2.31倍,骨小梁厚度 (Tb.Th)增加了1.56倍,而骨小梁分离度（Tb.Sp)降低了 1.65倍（P<0.05)。骨生物力学结果表明,相对Control组而言,Sr 组,PTH组及PTH+Sr组的最大推力分别增加了 1.27倍、1.36倍及1.61倍（P<0.05)。组织学结果显示12w时,Sr组,PTH 组及PTH + Sr组的骨面积比率（BAR)相较于Control组分别提高了 1. 52倍、1. 73倍及2. 30倍（P < 0. 05),其骨-种植体接触率 (BIC)分别提高了 1.35倍、1.56倍及2. 21倍（P<0.05)。结论 掺锶羟基磷灰石涂层结合PTH (1-34)可以加强植人体在骨质疏松骨中的骨整合。     

Human parathyroid hormone (1-34) accelerates natural fracture healing process in the femoral osteotomy model of cynomolgus monkeys

Several studies in rats have demonstrated that parathyroid hormone accelerates fracture healing by increasing callus formation or stimulating callus remodeling. However the effect of PTH on fracture healing has not been tested using large animals with Haversian remodeling system. Using cynomolgus monkey that has intracortical remodeling similar to humans, we examined whether intermittent treatment with human parathyroid hormone [hPTH(1–34)] accelerates the fracture healing process, especially callus remodeling, and restores geometrical shapes and mechanical properties of osteotomized bone.

Seventeen female cynomolgus monkeys aged 18–19 years were allocated into three groups: control (CNT, n = 6), low-dose PTH (0.75 μg/kg; PTH-L, n = 6), and high-dose PTH (7.5 μg/kg; PTH-H, n = 5) groups. In all animals, twice a week subcutaneous injection was given for 3 weeks. Then fracture was produced surgically by transversely cutting the midshaft of the right femur and fixing with stainless plate. After fracture, intermittent PTH treatment was continued until sacrifice at 26 weeks after surgery. The femora were assessed by soft X-ray, three-point bending mechanical test, histomorphometry, and degree of mineralization in bone (DMB) measurement. Soft X-ray showed that complete bone union occurred in all groups, regardless of treatment. Ultimate stress and elastic modulus in fractured femur were significantly higher in PTH-H than in CNT. Total area and percent bone area of the femur were significantly lower in both PTH-L and PTH-H than in CNT. Callus porosity decreased dose-dependently following PTH treatment. Mean DMB of callus was significantly higher in PTH-H than in CNT or PTH-L. These results suggested that PTH decreased callus size and accelerated callus maturation in the fractured femora.

PTH accelerates the natural fracture healing process by shrinking callus size and increasing degree of mineralization of the fracture callus, thereby restoring intrinsic material properties of osteotomized femur shaft in cynomolgus monkeys although there were no significant differences among the groups for structural parameters.     

rhPTH(1-34)对骨质疏松大鼠的作用及对sclerostin的影响

[目的]探讨人重组甲状旁腺素1-34(rhPTH1-34)对骨质疏松的治疗作用以及与血钙、磷代谢和生长因子的关系。[方法]用摘除大鼠双侧卵巢的方式制备骨质疏松模型,实验动物分为3个组:模型对照组(OVX组,摘除大鼠双侧卵巢不作任何处理);rhPTH1-34治疗组(PTH组,摘除大鼠双侧卵巢12周后用rhPTH1-34治疗8周);假手术组(sham组,仅切除卵巢周围的脂肪组织约3 g,术后12周纳入实验)。应用第4代双能X线骨密度仪测量大鼠股骨上段骨密度值(BMD);用ELISA法测定血清硬化蛋白(sclerostin)水平及骨钙素(BGP)浓度;用自动生化仪测定血清碱性磷酸酶(ALP)。[结果]rhPTH1-34治疗组、sham组均较OVX组股骨上段骨密度增高,组间比较差异有显著性(P<0.01)。rhPTH1-34治疗组血清BGP浓度值升高及sclerostin值降低,与OVX组比较差异有显著性(P<0.01)。各组血清钙、磷含量无明显变化,与OVX组比较差异无显著性,ALP值治疗组与OVX组无明显差异。[结论]rhPTH1-34能够预防股骨上段骨密度丢失,并且血清BGP浓度值升高及sclerostin值降...     

Human parathyroid hormone (1-34) accelerates the fracture healing process of woven to lamellar bone replacement and new cortical shell formation in rat femora

This study aimed to test whether intermittent treatment of human parathyroid hormone [hPTH(1-34)] disturbs or accelerates the fracture healing process using rat surgical osteotomy model. One hundred five, 5-week-old SD rats were allocated to vehicle control (CNT) and four PTH groups; 10 and 30 microg/kg of hPTH(1-34) treatment before surgery (P10, P30), and treatment before and after surgery (C10, C30). All animals were given subcutaneous injections three times a week for 3 weeks. Then, fractures were produced by transversely cutting the midshaft of bilateral femora and fixing with intramedullary wire. Human PTH(1-34) treatment was continued in C10 and C30 groups until sacrifice at 3, 6, and 12 weeks after surgery. The femora were assessed by peripheral quantitative computed tomography, three-point bending mechanical test, and histomorphometry. Total cross-sectional area was not significantly different among all groups at any time point. At 3 weeks after surgery, the lamellar bone/callus area was significantly increased in C10 and C30 groups compared to the other groups. At 6 weeks, remodeling of woven bone to lamellar bone in the callus was almost complete in all groups. At 12 weeks, percent new cortical shell area was significantly higher in C10 and C30 groups compared to the other groups, and the ultimate load in mechanical testing was significantly higher in C30 group than in CNT, P10, and P30 groups. Intermittent PTH treatment at 30 microg/kg before and after osteotomy accelerated the healing process as evidenced by earlier replacement of woven bone to lamellar bone, increased new cortical shell formation, and increased the ultimate load up to 12 weeks after osteotomy.     

Human parathyroid hormone 1-34 reverses bone loss in ovariectomized mice.

The experimental work characterizing the anabolic effect of parathyroid hormone (PTH) in bone has been performed in nonmurine ovariectomized (OVX) animals, mainly rats. A major drawback of these animal models is their inaccessibility to genetic manipulations such as gene knockout and overexpression. Therefore, this study on PTH anabolic activity was carried out in OVX mice that can be manipulated genetically in future studies. Adult Swiss-Webster mice were OVX, and after the fifth postoperative week were treated intermittently with human PTH(1-34) [hPTH(1-34)] or vehicle for 4 weeks. Femoral bones were evaluated by microcomputed tomography (microCT) followed by histomorphometry. A tight correlation was observed between trabecular density (BV/TV) determinations made by both methods. The BV/TV showed >60% loss in the distal metaphysis in 5-week and 9-week post-OVX, non-PTH-treated animals. PTH induced a approximately 35% recovery of this loss and a approximately 40% reversal of the associated decreases in trabecular number (Tb.N) and connectivity. PTH also caused a shift from single to double calcein-labeled trabecular surfaces, a significant enhancement in the mineralizing perimeter and a respective 2- and 3-fold stimulation of the mineral appositional rate (MAR) and bone formation rate (BFR). Diaphyseal endosteal cortical MAR and thickness also were increased with a high correlation between these parameters. These data show that OVX osteoporotic mice respond to PTH by increased osteoblast activity and the consequent restoration of trabecular network. The Swiss-Webster mouse model will be useful in future studies investigating molecular mechanisms involved in the pathogenesis and treatment of osteoporosis, including the mechanisms of action of known and future bone antiresorptive and anabolic agents.     

Restoration of spinal bone in osteoporotic men by treatment with human parathyroid hormone (1-34) and 1,25-dihydroxyvitamin D

Daily subcutaneous injection of a synthetic human parathyroid hormone fragment, combined with daily ingestion of 1,25(OH)2 vitamin D, significantly increased trabecular bone density in the spine (p less than .01), and improved intestinal calcium and phosphorus absorption and total body retention of dietary calcium and phosphorus in middle-aged men with idiopathic osteoporosis. The increases in spinal bone mineral were marked and progressive during a year of treatment. These results indicate that increasing intestinal absorption of dietary calcium while simultaneously stimulating new bone formation with small doses of parathyroid hormone can restore spinal bone in osteoporotic men.     

联合使用甲状旁腺激素和辛伐他汀对去卵巢大鼠骨质疏松症的治疗有叠加效应

目的探索联合使用甲状旁腺激素(PTH)和辛伐他汀(SIM)对去势大鼠骨质疏松的防治作用。方法 50只健康雌性SD大鼠随机行假手术(Sham,N=10)和切除双侧卵巢(OVX,N=40)手术后,OVX大鼠随机的分成4组:OVX组、SIM组、PTH组、PTH+SIM组。术后第1天开始给予药物治疗,SIM组:SIM灌胃(剂量5 mg/kg,每天1次),PTH组:PTH皮下注射(剂量60μg/kg,每周3次),PTH+SIM组:SIM灌胃和PTH皮下注射,剂量和用药频率和SIM组、PTH组相同,直至手术后12周为止,12时所有大鼠处死取胫骨行Micro-CT检测。结果结果表明SIM组、PTH组、PTH+SIM组和OVX组相比,胫骨近端都有较高的BMD、BV/TV、Tb.Th、Tb.N、Conn.D和较低的Tb.Sp,其中PTH+SIM组大鼠胫骨近端有最高的BMD、BV/TV、Tb.Th、Tb.N、Conn.D和最低Tb.Sp。SIM和PTH单独使用的效果明显低于他们联合使用对去卵巢大鼠骨质疏松的防治作用。结论联合使用甲状旁腺激素和辛伐他汀对去势大鼠骨质疏松的防治有叠加作用     

Recombinant human parathyroid hormone (1-34) [teriparatide] improves both cortical and cancellous bone structure.

Histomorphometry and microCT of 51 paired iliac crest biopsy specimens from women treated with teriparatide revealed significant increases in cancellous bone volume, cancellous bone connectivity density, cancellous bone plate-like structure, and cortical thickness, and a reduction in marrow star volume. INTRODUCTION: We studied the ability of teriparatide (rDNA origin) injection [rhPTH(1-34), TPTD] to improve both cancellous and cortical bone in a subset of women enrolled in the Fracture Prevention Trial of postmenopausal women with osteoporosis after a mean treatment time of 19 months. This is the first report of a biopsy study after treatment with teriparatide having a sufficient number of paired biopsy samples to provide quantitative structural data. METHODS: Fifty-one paired iliac crest bone biopsy specimens (placebo [n = 19], 20 microg teriparatide [n = 18], and 40 microg teriparatide [n = 14]) were analyzed using both two-dimensional (2D) histomorphometry and three-dimensional (3D) microcomputed tomography (microCT). Data for both teriparatide treatment groups were pooled for analysis. RESULTS AND CONCLUSIONS: By 2D histomorphometric analyses, teriparatide significantly increased cancellous bone volume (median percent change: teriparatide, 14%; placebo, -24%; p = 0.001) and reduced marrow star volume (teriparatide, -16%; placebo, 112%; p = 0.004). Teriparatide administration was not associated with osteomalacia or woven bone, and there were no significant changes in mineral appositional rate or wall thickness. By 3D cancellous and cortical bone structural analyses, teriparatide significantly decreased the cancellous structure model index (teriparatide, -12%; placebo, 7%; p = 0.025), increased cancellous connectivity density (teriparatide, 19%; placebo, - 14%; p = 0.034), and increased cortical thickness (teriparatide, 22%; placebo, 3%; p = 0.012). These data show that teriparatide treatment of postmenopausal women with osteoporosis significantly increased cancellous bone volume and connectivity, improved trabecular morphology with a shift toward a more plate-like structure, and increased cortical bone thickness. These changes in cancellous and cortical bone morphology should improve biomechanical competence and are consistent with the substantially reduced incidences of vertebral and nonvertebral fractures during administration of teriparatide.     

Mechanical loading enhances the anabolic effects of intermittent parathyroid hormone (1-34) on trabecular and cortical bone in mice

The separate and combined effects of intermittent parathyroid hormone (iPTH) (1-34) and mechanical loading were assessed at trabecular and cortical sites of mouse long bones. Female C57BL/6 mice from 13 to 19 weeks of age were given daily injections of vehicle or PTH (1-34) at low (20 microg/kg/day), medium (40 microg/kg/day) or high (80 microg/kg/day) dose. For three alternate days per week during the last two weeks of this treatment, the tibiae and ulnae on one side were subjected to a single period of non-invasive, dynamic axial loading (40 cycles at 10 Hz with 10-second intervals between each cycle). Two levels of peak load were used; one sufficient to engender an osteogenic response, and the other insufficient to do so. The whole tibiae and ulnae were analyzed post-mortem by micro-computed tomography with a resolution of 5 microm. Treatment with iPTH (1-34) modified bone structure in a dose- and time-dependent manner, which was particularly evident in the trabecular region of the proximal tibia. In the tibia, loading at a level sufficient by itself to stimulate osteogenesis produced an osteogenic response in the low-dose iPTH (1-34)-treated trabecular bone and in the proximal and middle cortical bone treated with all doses of iPTH (1-34). In the ulna, loading at a level that did not by itself stimulate osteogenesis was osteogenic at the distal site when combined with high-dose iPTH (1-34). At both levels of loading, there were synergistic effects in cortical bone volume of the proximal tibia and distal ulna between loading and high-dose iPTH (1-34). Images of fluorescently labelled bones confirmed that such synergism resulted from increases in both endosteal and periosteal bone formation. No woven bone was induced by iPTH (1-34) or either level of loading alone, whereas the combination of iPTH (1-34) and the "sufficient" level of loading stimulated woven bone formation on endosteal and periosteal surfaces of the proximal cortex in the tibiae. Together, these data suggest that in female C57BL/6 mice, under some but not all circumstances, mechanical loading exerts an osteogenic response with iPTH (1-34) in trabecular and cortical bone.