The use of a coral composite implant containing bone morphogenetic protein to repair a segmental tibial defect in sheep

Summary. A composite implant consisting of a coral cylinder, moose bone morphogenetic protein and type IV collagen was used to repair a segmental tibial defect in sheep. Healing, related variance in mechanical strength and immune responses were evaluated. In comparison with a coral control, a larger amount of newly formed external callus was observed in the composite group at 6 weeks. The maximal torque capacity, maximal angular deformation at failure and bone stiffness of a healed osteotomised tibia recovered 113%, 117% and 120% in the coral controls and 67%, 92% and 79% in the composite implants against the corresponding contralateral tibia at 16 weeks respectively. A significantly elevated anti-BMP antibody was detectable in the composite group at 3 and 6 weeks. Augmented bone formation at an early stage and weakened torsional performance at a later stage in the composite implants may indicate the phase-specific osteoinduction and the immune response of xenogenic BMP with time.

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Résumé. Nous avons étudié l’action d’un composite comprenant un cylindre de corail, une protéine morphogénétique xénogénique extraite de l’os de souris et du collagène de type IV, sur la consolidation la résistance mécanique et la réponse immune d’une perte de substance diaphysaire. L’étude au scanner à 6 semaines a montré une réduction significative du cal dans le groupe composite. A 16 semaines, la résistance à la torsion, la déformation angulaire maximale et la solidité des cals consolidés ont été respectivement de 113%, 117% et 120% dans le groupe controle, et de 67%, 92% et 79% dans le groupe composite, comparées au tibiai contralatéral. Dans le groupe composite, il y a eu une élévation significative des anticorps anti-mBMP. L’augmentation de la formation osseuse au stade précoce et la diminuation des propriétés mécaniques au stade tardif dans le groupe composite, pourraient être l’expression d’une induction séquentielle de l’ostéogenèse et d’une initiation immune des antigènes mBMP xénogéniques après une greffe hétérotopique.

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Accepted: 2 January 1997     

Regeneration of an enchondroma defect under the influence of an implant of human bone morphogenetic protein

A 29-year-old woman with an enchondroma that was expanding and eroding the palmar cortex of the middle phalanx was successfully treated by curettage and implantation of bone morphogenetic protein. The metaphysis and cortex were repaired by lamellar bone within 2 months. The medulla was completely filled with trabecular bone by 9 months. The full range of motion and normal functions of finger and hand joints were restored, and there was no recurrence or abnormalities at follow-up visits 2 1/2 years after the operation.     

Bovine bone implant with bovine bone morphogenetic protein in healing a canine ulnar defect

Xenograft is considered an alternative material for bone transplantation, but its bone healing capacity is inferior compared to that of autografts and allografts. Here, we tested whether bone morphogenetic protein (BMP) addition enhances the suitability of demineralized xenogeneic bovine bone for bone grafting in dogs, and whether xenogeneic bone is a suitable carrier material for BMPs. The capacity of demineralized bovine bone implants, with and without native partially purified bovine BMP, to heal a 2-cm ulnar defect was determined in six dogs over a follow-up time of 20 weeks. No instances of bone union were seen, but there was slightly more bone formation in the xenografts with BMP, though the difference was not statistically significant. The ulnas treated with an implant with BMP were also mechanically stronger, but the difference was not significant. Computed tomography scans showed no differences in the implant area in bone density, bone mineral content, or bone cross-sectional area. It is concluded that native, partially purified BMP does not sufficiently improve the suitability of bovine demineralized xenografts as a bone substitute material for dog. Demineralized xenogeneic bone does not seem to be a feasible carrier material for BMP.     

Human bone morphogenetic protein allografting for reconstruction of femoral nonunion

A composite inductive allograft consisting of an allogeneic, autolysed, antigen-free cortical bone carrier lyophilized with partially purified human bone morphogenetic protein was implanted in 30 consecutive femoral reconstructions that resulted from failure of fracture healing. There were 24 atrophic shortened femoral nonunions, four equal length femoral nonunions, and two femoral malunions. There were 10 men and 20 women with an average age of 47 years (range, 28-75 years). Allogeneic, autolysed antigen-free cortical bone was used as a structural alloimplant and as a delivery system for partially purified human bone morphogenetic protein. The composite implant of human bone morphogenetic protein/allogeneic, autolysed antigen-free cortical bone was used in conjunction with one-stage lengthening of the extremity, restoration of mechanical axis and rotational alignment. In 26 of 30 femurs, the human bone morphogenetic protein/allogeneic autolysed antigen-free cortical bone consisted of an allogeneic cortical bone implant incorporated into a one-stage lengthening of atrophic femoral nonunion. In four patients with equal length femoral nonunions, the human bone morphogenetic protein/allogeneic, autolysed antigen-free implant was placed as an medical femoral shaft onlay graft. Internal remodeling of the implant occurred within 8 to 12 weeks after implantation. Lengthening defects greater than 2 cm were supplemented with intercalary autogeneic bone graft. Twenty-four femurs healed at an average of 6 months at an average followup of 55 months. Four of six plate fatigue failures were salvaged with repeat plating. Two patients were lost to followup. The human bone morphogenetic protein/allogeneic, autolysed antigen-free bone allograft is an excellent structural and delivery system that induces host bone formation and implant remodeling allowing salvage of difficult femoral nonunions.     

骨形态发生蛋白在股骨头坏死治疗中的应用进展

股骨头坏死的治疗强调早期治疗,预防和延缓股骨头塌陷.髓芯减压或植骨手术的同时将生长和分化因子应用到坏死区域来促进坏死骨修复,是近年研究的热点.骨形态发生蛋白(BMP)是高效的骨诱导因子,将BMP直接或复合移植骨植入股骨头坏死区域,可诱导局部成骨,促进坏死骨修复,在实验和临床研究中均显示出良好的治疗效果;将BMP与人工载体材料复合植入,既利用载体的骨传导作用和机械支撑作用,又发挥BMP的骨诱导活性,同时又使BMP在局部持续有效地发挥作用,成为治疗股骨头坏死的新方法;BMP基因导入治疗虽然刚刚起步,但初步的实验研究已证实,它可促进股骨头坏死骨的修复并改善股骨头的力学性能.     

Composite implant composed of hydroxyapatite and bone morphogenetic protein in the healing of a canine ulnar defect

BACKGROUND AND AIMS: Hydroxyapatite (HA) has been considered as a carrier material for bone morphogenetic proteins (BMP). The aim of this study was to evaluate the capacity of a composite implant of HA and native bovine BMP to heal a 2 cm segmental defect in the canine ulna. MATERIALS AND METHODS: A composite HA+BMP implant was compared with plain HA implants and cortical autografts. The fixation was accomplished with an intramedullary Kirschner wire. The bone union was evaluated by X-rays taken at operation and after 3, 6, 9, 12, 16, 25, 35 weeks and by histology and mechanical torsion tests. RESULTS: HA implants were not able to produce complete bone union even with BMP. There was some bridging between the implant and the bone in the defects treated with either plain HA or HA+BMP implant, the bridging being slightly more pronounced with HA+BMP. The autografts showed a significantly better capacity to heal the defect. The HA implant did not resorb markedly during the study. There was no significant difference in mechanical strength between the HA and HA+BMP groups. CONCLUSIONS: HA was not an adequate bone substitute material in this study model, and BMP was not able to enhance sufficiently the poor capacity of HA to heal canine ulnar defects.     

Response of the rabbit metaphysis to implants of bovine bone morphogenetic protein (bBMP)

The response of protodifferentiated and differentiated bone cells to bovine bone morphogenetic protein (bBMP) was observed in implants in the adult rabbit distal femoral metaphysis. Bovine serum albumin and denatured bBMP were implanted in the contralateral femur of controls. The changes of the bone marrow reflected the reaction of protodifferentiated cells. The changes in preexisting trabecular bone tissue reflected the reaction of differentiated cells to bBMP. 45Ca radioisotope quantitative methods demonstrated that the bone morphogenetic response was superimposed upon the reaction to the injury of surgical implantation. By the end of the fourth week, roentgenograms and histologic sections showed larger deposits of intrametaphyseal cartilage and bone in bBMP than in control implanted femurs. By the end of the eighth week, bone formation was associated with remodeling of the entire distal femur and expansion of the external diameter of the metaphysis. These observations indicate the need for investigation of perisinusoid and perivascular cells of periosteum, endosteum, and marrow stroma that are undifferentiated with respect to cartilage and bone but are principal target tissues for BMP.     

Treatment of osteonecrosis of the femoral head with core decompression and human bone morphogenetic protein

A retrospective evaluation was done of 15 patients (17 hips) with symptomatic osteonecrosis of the hip treated with core decompression combined with an allogeneic, antigen-extracted, autolyzed fibula allograft and 50 mg of partially purified human bone morphogenetic protein and noncollagenous proteins. The average duration of clinical followup of the patients was 53 months (range, 26-94 months). The osteonecrotic involvement of the hip was classified by plain radiographs using a modification of the Ficat staging system and MRI evaluations. Fifteen hips were classified as Ficat Stage IIA, one hip (one patient) was classified as Ficat Stage IIB, and one hip (one patient) was classified as Ficat Stage III. Fourteen hips had involvement of 50% or less of the femoral head and 2/3 or less involvement of the weight-bearing surface of the femoral head, based on a magnetic resonance imaging evaluation. The procedures were a clinical success in 14 of 15 hips (93%; 13 patients) with Stage IIA disease. Three of 17 hips (three patients) had radiographic progression (Ficat Stages IIA, IIB, and III) of the femoral head and were converted to total hip replacements. Only one of seven hips (six patients) with 50% or less involvement of the femoral head and between 1/3 and 2/3 of the weightbearing surface of the femoral head developed radiographic progression of the femoral head. There was no radiographic progression in the 3 hips with less than 1/3 involvement of the weightbearing surface of the femoral head. Further evaluation of the potential efficacy of bone morphogenetic protein is required in randomized trials.     

一种新型生物活性人工骨的制备及成骨活性的研究

目的：研制CPC/BMP复合人工骨,检测其成骨活性。方法：制备CPC/BMP及CPC骨块,扫描电子显微镜观察表面结构。用小鼠肌袋植入实验观察材料的成骨活性。结果：BMP在CPC中呈微球状均匀分布。CPC植入小鼠肌袋内不能诱导,CPC/BMP植入后1周有软骨细胞出现,2周有编织骨,4周以后小梁骨生成,16周出现成熟的板层骨。同时材料出现降解迹象。有机质含量、碱性磷酸酶浓度在CPC/BMP组出现升高,扫描电镜结果同样证实有新骨形成。结论：CPC/BMP生物活性人工骨可异位诱导成骨,可望成为新型的骨缺损修复材料。     

Solubilized bone morphogenetic protein (BMP) from mouse osteosarcoma and rat demineralized bone matrix

A selection of proteins including bone morphogenetic protein (BMP) was extracted in a disaggregated form from Dunn osteosarcoma or rat demineralized bone matrix by 4M guanidine hydrochloride (GuHCl) solution without losing its biological activity. The GuHCl extracts of Dunn osteosarcoma were divied into 4 different fractions by cesium chloride (CsCl) density gradients. Under a dissociative condition, the highest new bone yield was obtained in the low dense top one-third fraction, and BMP acitivity declined with increase in the density of each fraction. No BMP potential was observed in the surface-gel fraction under dissociative conditions. Under an associative condition (low GuHCl concentrations), BMP activity appears in the surface-gel fraction, while under a dissociative condition (high concentrations of GuHCl) BMP appears in the fraction below the surface gel. These facts suggest that under associative conditions, BMP aggregates with other low dense proteins in the surface-gel fraction and that this may be the state of aggregation of BMP in cells and matrix in nature. Present observations support the assumption that BMP is a relatively low density protein and excludes the idea of BMP activity in the collagen molecule, per se. A specific protein, with an apparent molecular weight of 63,000 daltons, is present in all fractions that exhibit BMP activity, and absent in fractions that do not exhibit this activity. BMP is not species-specific; rat BMP induces bone formation in mice. CsCl density-gradient centrifugation is an efficient tool for further purification and isolation of BMP.     

Early biological fixation of porous implant coated with paste-retaining recombinant bone morphogenetic protein 2

The aim of this study was to evaluate the period required for stable initial bone-implant fixation with recombinant human bone morphogenetic protein 2 (rhBMP-2) in the bone marrow of a rabbit model. The porous implants being coated with β-tricalcium phosphate/polylactide-polyethylene glycol paste with 15, 30, or 60 μg of rhBMP-2 (n = 10) were implanted into animals in 3 experimental groups. In 2 control groups, the test implants were coated without rhBMP or no paste. In all groups, the implant was inserted for 3 and 6 weeks. At 3 weeks after implantation, the BMP-treated implants in the 2 lower dose groups had significantly more bone ingrowth to the implant surface than did the control groups, and the greatest effect occurred in the 30-μg rhBMP-2 group animals.     

带血供肌瓣作为骨形态发生蛋白载体修复骨缺损的实验研究

目的 探讨带血供肌瓣作为骨形态发生蛋白（BMP）载体修复骨缺损的可行性。方法 观察带血从肌瓣复合BMP和单纯BMP组修复骨缺损时的成骨情况;对纤维蛋白粘合剂、带血供肌瓣、无血运肌瓣、同种异体脱钙骨4种不同BMP载体的成骨能力进行比较。结果 以指深屈肌支为蒂制备的带血供肌瓣复合BMP修复骨缺损,效果优于单纯BMP组;带血供肌瓣联合纤维蛋白粘合剂复合BMP修复骨缺损,效果优于单纯BMP组;带血供肌瓣联合纤维蛋白粘合剂复合BMP组修复骨缺损,效果优于其它载体。结论 带血供肌瓣可作为BMP的良好载体。带血供肌瓣联合纤维蛋白粘合剂作BMP的载体效果更优。     

牛骨形态发生蛋白加自体髂骨植入治疗儿童股骨头缺血性坏死

目的 探讨牛骨形态发生蛋白（ｂＢＭＰ）＋自体髂骨植入治疗儿童股骨头缺血性坏死的疗效。方法 自体髂骨植入１０２髋,ｂＢＭＰ植入３７髋,ｂＢＭＰ＋自体髂骨植入６９髋。比较３种手术方法疗效。结果 随访６个月～１５年,３种手术方法中以ｂＢＭＰ＋自体髂骨植入组疗效为最优。结论 ｂＢＭＰ＋自体髂骨植入治疗儿童股骨头缺血性坏死疗效显著。     

Altered plasma membrane dynamics of bone morphogenetic protein receptor type Ia in a low bone mass mouse model

Bone morphogenetic proteins (BMPs) are growth factors that initiate differentiation of bone marrow stromal cells to osteoblasts and adipocytes, yet the mechanism that decides which lineage the cell will follow is unknown. BMP2 is linked to the development of osteoporosis and variants of BMP2 gene have been reported to increase the development of osteoporosis. Intracellular signaling is transduced by BMP receptors (BMPRs) of type I and type II that are serine/threonine kinase receptors. The BMP type I a receptor (BMPRIa) is linked to osteogenesis and bone mineral density (BMD). BMPRs are localized to caveolae enriched with Caveolin1 alpha/beta and Caveolin beta isoforms to facilitate signaling. BMP2 binding to caveolae was recently found to be crucial for the initiation of the Smad signaling pathway. Here we determined the role of BMP receptor localization within caveolae isoforms and aggregation of caveolae as well as BMPRIa in bone marrow stromal cells (BMSCs) on bone mineral density using the B6.C3H-6T as a model system. The B6.C3H-6T is a congenic mouse with decreased bone mineral density (BMD) with increased marrow adipocytes and decreased osteoprogenitor proliferation. C57BL/6J mice served as controls since only a segment of Chr6 from the C3H/HeJ mouse was backcrossed to a C57BL/6J background. Family of image correlation spectroscopy was used to analyze receptor cluster density and co-localization of BMPRIa and caveolae. It was previously shown that BMP2 stimulation results in an aggregation of caveolae and BMPRIa. Additionally, BMSCs isolated from the B6.C3H-6T mice showed a dispersion of caveolae domains compared to C57BL/6J. The aggregation of BMPRIa that is necessary for signaling to occur was inhibited in BMSCs isolated from B6.C3H-6T. Additionally, we analyzed the co-localization of BMPRIa with caveolin-1 isoforms. There was increased percentage of BMPRIa co-localization with caveolae compared to C57BL/6J. BMP2 stimulation had no effect on the colocalization of BMPRIa with caveolin-1. Disrupting caveolae initiated Smad signaling in the isolated BMSCs from B6.C3H-6T. These data suggest that in congenic 6T mice BMP receptors aggregation is inhibited causing an inhibition of signaling and reduced bone mass.     

Evaluation in cats of a new material for cranioplasty: a composite of plaster of Paris and hydroxylapatite

The materials ordinarily used to reconstruct bone defects in the calvaria and facial bones either are difficult to shape, are partially resorbed by the body, or are likely to become infected if used near a contaminated area such as the frontal sinus. Calcium sulfate hemihydrate (plaster of Paris) has been known for years to have excellent reparative qualities in bone defects, but ordinarily it is quickly resorbed. Consequently, a new material, a composite of a dense form of plaster of Paris and hydroxylapatite, was devised to provide nonabsorbable hydroxylapatite particles for bone to form around and within during the phase of plaster absorption. Two types of this material were evaluated in cranial defects in cats. Each of the plaster of Paris/hydroxylapatite mixtures was placed into a surgically unroofed frontal sinus and into a contralateral parietal trephine hole in a group of 32 cats. Two cats in each group succumbed to anesthesia, leaving two sets of 30 cats. During the entire follow-up period there was only one other death, with no evidence of wound infection, wound dehiscence, implant rejection, or cerebral dysfunction among the survivors. The cats in each group were sacrificed at 1, 2, 3, 5, 7, 8, 9, 10, or 12 months after operation. Following sacrifice, both the frontal and parietal defects were exposed and examined visually, histologically, and with histomorphometric analysis for new bone formation. New bone formation was present as early as 1 month after operation and continued to increase during the 12 months of the study. Based upon these osteogenic qualities, the ease of shaping the composite, and the lack of infection in the frontal sinus region, it is concluded that this substance could be a valuable new material for human cranioplasty.     

加入和未加骨形态发生蛋白2的打压植骨术治疗股骨头坏死

背景：已知骨形态发生蛋白2（bone morphogenetic protein2,BMP2）能促进骨愈合,但能否加速股骨头坏死打压植骨术的修复尚不知。目的：回顾性对照分析加入和未加入BMP2的打压植骨术治疗股骨头坏死（osteonecrosis of the femoral head,ONFH）的疗效。方法：42例（72髋）非创伤性ONFH手术患者获得随访,男19例,女23例;手术时年龄22~54岁,平均30.9岁。手术方法为经髋关节前路,股骨头颈交界处开窗,坏死灶清除,人工骨打压植骨。第一组每例加入4mgrhBMP2,第二组未加。患髋按国际骨循环学会（Association Research Circulation Osseous,ARCO）分期,按中日友好医院（China-Japan Friend-ship Hospital,CJFH）分型。临床疗效按Harris髋关节功能评分（Harris hip score,HHS）评定,影像学按股骨头是否塌陷及病灶修复情况评定。结果：随访5~7.8年（平均6.1年）。优36髋,良12髋,尚可7髋。股骨头保存率76.4%,第一组为81.8%,第二组为71.8%（P=0.459）。ARCOⅡ期为90.3%,Ⅲa期为34.6%（P=0.0285）;CJFH-C型及L1型为95.3%,L3型为29.6%（P=0.050）。结论：经股骨头颈开窗病灶清除,打压植骨术在选择合适的非创伤ONFH患者（ARCOⅡb,c期及CJFHC型和L1型）可获得优良的中期疗效。加入rhBMP2可提高手术疗效和骨修复质量。     

Intramedullary application of bone morphogenetic protein in the management of a major bone defect after an Ilizarov procedure

We describe a patient with insufficient bone regeneration of the tibia after bone transport over an intramedullary nail, in whom union was ultimately achieved after exchange nailing and intramedullary application of rh-bone morphogenetic protein-7 at the site of distraction.