Maxillary sinus floor elevation using a tissue-engineered bone complex with β-TCP and BMP-2 gene-modified bMSCs in rabbits

Objectives: To study the effects of maxillary sinus floor elevation by a tissue‐engineered bone complex with β tricalcium phosphate (β‐TCP) and bone morphogenetic protein‐2 (BMP‐2) gene‐modified bone marrow stromal cells (bMSCs) in rabbits. Material and methods: bMSCs derived from New Zealand rabbit bone marrow were cultured and transduced with the adenovirus with BMP‐2 (AdBMP‐2), adenovirus with enhanced green fluorescent protein gene (AdEGFP) in vitro. Gene transfer efficiency was detected by EGFP expression. These gene‐modified autologous bMSCs were then combined with a β‐TCP granule scaffold at a concentration of 2 × 10⁷ cells/ml and used to elevate the maxillary sinus floor in rabbits. Twenty rabbits were randomly allocated into groups and sacrificed at weeks 2 and 8. For each time point, 20 maxillary sinus floor elevation surgeries were made bilaterally in 10 rabbits for the following groups (n=5 per group): group A (β‐TCP alone), group B (untransduced bMSCs/β‐TCP), group C (AdEGFP–bMSCs/β‐TCP), and group D (AdBMP‐2–bMSCs/β‐TCP). All samples were evaluated by histology and histomorphometric analysis. The fate of implanted bMSCs was traced initially by a confocol fluorescent microscope in the AdEGFP group. Results: Gene transfer efficiency reached up to 60–80% with 50 PFU/cell transduction as demonstrated by fluorescent microscopic analysis in the AdEGFP group. The augmented maxillary sinus height was maintained for the four groups till 8 weeks post‐surgery, while new bone area increased over the time. At week 2, bone areas in groups B–D were significantly larger than those in group A, while at week 8, in group D, the BMP‐2 gene‐enhanced tissue‐engineered bone had the largest bone area among the groups (P<0.05, ANOVA). In that group, a mature bone structure was detected in the center of the elevated space. Under a confocal microscope, green fluorescence in newly formed bone was observed for the EGFP group, which suggested that those implanted bMSCs might have contributed to the new bone formation. Conclusion: bMSCs modified with the AdBMP‐2 gene can promote new bone formation and maturation in the rabbit maxillary sinus. BMP‐2 regional gene therapy and a tissue engineering technique could be effectively used in maxillary sinus elevation and bone regeneration.     

Nell-1基因修饰骨髓基质细胞复合β-磷酸三钙提升兔上颌窦底的实验研究

目的：评价Nel样I型分子（Nell-1）基因修饰骨髓基质细胞（bone marrow stromal cells,bMSCs）复合β-磷酸三钙提升兔上颌窦底的效果。方法：抽取兔骨髓进行bMSCs培养,体外采用腺病毒载体携带Nell-1基因（AdNell-1）及绿色荧光蛋白EGFP基因（AdEGFP）转染bMSCs,GFP表达检测转染效率、Nell-1免疫细胞化学检测目的基因的表达。碱性磷酸酶（ALP）染色、半定量检测及钙结节茜素红染色检测细胞成骨分化。将基因修饰bMSCs与β-磷酸三钙颗粒复合用于兔上颌窦底提升,分别在术后2周和8周取材,HE染色,测量成骨面积,并采用SPSS11.0软件包对2组间数据进行t检验。结果：AdEGFP基因修饰组GFP表达效率可达60%～80%,Nell-1细胞化学染色显示,AdNell-1基因修饰组呈阳性表达。AdNell-1基因修饰组ALP染色及钙结节茜素红染色均高于AdEGFP基因修饰组,ALP半定量检测具有统计学差异（P〈0.05）。体内实验研究中,AdNell-1基因修饰组新骨形成面积在8周时显著高于AdEGFP基因修饰组（P〈0.05）。结论：采用AdNell-1基因转染兔bMSCs可促进其成骨分化,体内可促进上颌窦底提升的效果。     

Sinus floor augmentation with recombinant human growth and differentiation factor-5 (rhGDF-5): a pilot study in the Goettingen miniature pig comparing autogenous bone and rhGDF-5

Aim: The aim of this study was to test the hypothesis that recombinant human growth and differentiation factor-5 (rhGDF-5) in combination with a β-tricalcium phosphate (β-TCP) scaffold material results in superior bone formation in sinus floor augmentations in miniature pigs compared with a particulated autogenous bone graft combined with the scaffold material.
Material and methods: Six adult female Goettingen minipigs underwent a maxillary sinus floor augmentation procedure. In a split-mouth design, the sinus floors were augmented with β-TCP mixed with autogenous cortical bone chips, in a ratio of approximately 1 : 1, on one side. The contralateral test site was augmented using β-TCP coated with two concentrations of rhGDF-5 (400 μg rhGDF-5/g β-TCP or 800 μg rhGDF-5/g β-TCP; three animals in each case). Simultaneously, one dental implant was inserted into each sinus floor augmentation. After 12 weeks, a histological and histomorphometric assessment of non-decalcified histological specimens was made.
Results: There were significantly higher mean values of volume density of newly formed bone using β-TCP coated with two concentrations of rhGDF-5 (400 μg: 32.9%; 800 μg: 23.9%) than with the corresponding control (autogenous bone/β-TCP) (14.6%, 12.9%) ( P =0.012, P =0.049). The bone-to-implant contact rates (BIC) were significantly enhanced in test sites (400 μg: 84.2%; 800 μg: 69.8%) compared with the corresponding control sites (24.8%, 40.8%) ( P =.027, P =.045).
Conclusion: rhGDF-5 delivered on β-TCP significantly enhanced bone formation compared with β-TCP combined with autogenous bone in sinus lift procedures in miniature pigs.     

腺病毒介导的骨形成蛋白-2基因修饰促进羊骨髓基质细胞成骨分化的实验研究

目的研究腺病毒介导的骨形成蛋白-2(AdBMP-2)基因转染对羊骨髓基质细胞生长、成骨分化的影响。方法抽取成年健康山羊骨髓,以贴壁培养法培养骨髓基质细胞。以AdBMP-2基因转染体外培养的羊骨髓基质细胞,倒置显微镜观察,计算基因转染效率,绘制细胞生长曲线,并行碱性磷酸酶染色及骨钙素定量分析。采用SAS6.2统计软件包对数据进行SNK法分析。结果细胞转染率达70%±3%,转染目的基因的细胞胞体肥大,呈多边形。生长曲线在AdBMP-2基因转染组、LacZ基因转染组和空白对照组之间无显著差别。目的基因转染后12d,碱性磷酸酶阳性染色面积较对照组增加。转染目的基因后6d,骨钙素含量显著增高,与对照组相比有统计学差异(P<0.01)。结论AdBMP-2基因转染促进了体外培养的骨髓基质细胞向成骨细胞表型转化,可望成为颌骨缺损修复的新型种子细胞。     

Maxillary sinus floor elevation using a tissue engineered bone complex with BMP-2 gene modified bMSCs and a novel porous ceramic scaffold in rabbits

Objectives

To study the effects of maxillary sinus floor elevation by a tissue engineered bone complex with bone morphogenetic protein-2 (BMP-2) gene modified bone marrow stromal cells (bMSCs) and a novel porous ceramic scaffold (OsteoBone™) in rabbits.

Materials and methods

bMSCs derived from New Zealand rabbit bone marrow were cultured and transduced with adenovirus AdBMP-2 and with AdEGFP gene (without BMP-2 gene sequence) as a control, respectively, in vitro. These bMSCs were then combined with OsteoBone™ scaffold at a concentration of 2 × 10⁷ cells/ml and used to elevate the maxillary sinus floor in rabbits. Eight rabbits were randomly allocated into groups and sacrificed at weeks 2 and 4. For each time point, 8 maxillary sinus floor elevation surgeries were made bilaterally in 4 rabbits for the two groups (n = 4 per group): group A (AdBMP-2-bMSCs/material) and group B (AdEGFP-bMSCs/material). All samples were evaluated by histologic and histomorphometric analysis.

Results

The augmented maxillary sinus height was maintained for both groups over the entire experimental period, while new bone area increased over time for group A. At week 4 after operation, bone area in group A was significantly more than that in group B (P < 0.05), and was more obviously detected in the center of the elevated space. Under a confocal microscope, green fluorescence in newly formed bone was observed in the EGFP group, which suggests that those implanted bMSCs had contributed to the new bone formation.

Conclusion

bMSCs modified with AdBMP-2 gene can promote new bone formation in elevating the rabbit maxillary sinus. OsteoBone™ scaffold could be an ideal carrier for gene enhanced bone tissue engineering.     

Effects of the combination with α-tricalcium phosphate and simvastatin on bone regeneration

Background: Although local application of statins stimulates bone formation, high dose of simvastatin induces inflammation.
Objective: A study was conducted to test the hypothesis that maximum bone regeneration with less inflammation would be achieved by combining an optimal dose of simvastatin with α-tricalcium phosphate (α-TCP), which is an osteoconductive biomaterial capable of releasing the drug gradually.
Material and methods: Bilateral 5-mm-diameter calvarial defects were created in adult Wistar rats and filled with preparations of different doses of simvastatin (0, 0.01, 0.1, 0.25 and 0.5 mg) combined with α-TCP particles or left empty. The animals were sacrificed at 2, 4 and 8 weeks and analyzed radiologically and histologically. Half of the animals of 4 and 8 weeks were labeled with fluorescence dyes and histomorphometrically analyzed.
Results: Simvastatin doses of 0.25 and 0.5 mg caused inflammation of the soft tissue at the graft site whereas control and other doses did not. The micro-CT analysis revealed that the α-TCP with 0.1 mg simvastatin (TCP-0.1) group yielded significantly higher bone volumes than untreated control group at all three time points (249%, 227% and 266% at 2, 4 and 8 weeks, respectively). The percentage of defect closure, bone mineral content and bone mineral density were also higher in the TCP-0.1 group than in the other groups.
Conclusion: When combined with α-TCP particles, 0.1 mg simvastatin is the optimal dose for stimulation of the maximum bone regeneration in rat calvarial defects without inducing inflammation and it could be applied as an effective bone graft material.     

Micro-CT analysis of alveolar bone healing using a rat experimental model of critical-size defects

Objective:  This study was designed to establish a rat model of a critical size alveolar bone defect.
Materials and methods:  Standardized buccal or mesiobuccal alveolar bone defects were made around the right first mandibular molar of 12-week-old rats, and the left was used as a control. Alveolar bone healing was examined quantitatively by three-dimensional micro-computed tomographic imaging. Bone matrix production of osteoblasts and osteocytes during repair of alveolar bone defects was examined with in situ hybridization for type I collagen.
Results:  Buccal defects were repaired significantly and the volume decreased by 88.3% in week 24, whereas mesiobuccal defects were repaired little. Osteoblasts and osteocytes expressed type I collagen in both defects in week 3 but showed little expression by week 6 and thereafter, leaving the mesiobuccal defects largely unrepaired.
Conclusion:  The mesiobuccal defect is a critical-size defect that is not ultimately repaired with bone. It may be an appropriate experimental model for investigating the effectiveness of bone regenerative agents in human alveolar bone loss.     

Transforming growth factor-β I coated β-tricalcium phosphate pellets stimulate healing of experimental bone defects of rat calvariae

OBJECTIVE: TGF-β I-coated β-TCP pellets were grafted in experimental defects of rat calvariae to study the effects on new bone formation.
MATERIALS AND METHODS: The grafted sites were evaluated by light microscopy using hematoxylin-eosin (H-E) staining for histology and detection of alkaline phosphatase (ALPase) and tartrate-resistant acid phos-phatase (TRACPase) activities to demonstrate osteo-blastic and osteoclastic cells. Confocal laser scanning microscopy (CLSM) was performed for morphometry of newly formed bone.
RESULTS: The sections showed more new bone formation in sites grafted with TGF-β I -coated β-TCP pellets (experimental sites) than those with β -TCP pellets only (control sites). TRACPase-positive and ALPase-positive cells at experimental sites were more frequent than at control sites. The bone formation rate calculated by computerized CLSM pixel image analysis showed more new bone formation at the experimental sites than at control sites (3.4 ± 0.8% vs 9.3 ± 1.7% on week 2 and 11.8 ± 2.1% vs 39.8 ± 10.9% on week 4).
CONCLUSION: TGF-P β I -coated β-TCP pellets promote new bone formation and may be a useful modality in synthetic bone grafting.     

Biphasic calcium phosphate ceramics in small bone defects: potential influence of carrier substances and bone marrow on bone regeneration

Objectives: Synthetic calcium phosphate bone substitutes such as hydroxyapatite (HA), β-tricalcium phosphate (β-TCP) or mixtures are alternatives to autogenous bone grafts. TricOs T^® and Collagraft^® are resorbable bone substitutes consisting of biphasic calcium phosphate and a bioactive matrix. Both products have a similar HA to β-TCP ratio, but differ by their matrix. It was the aim of this study to determine the influence of matrix and autologous bone marrow on bone regeneration in a rabbit femoral condyle model.
Material and methods: A critical-sized bicortical channel with a diameter of 4.5 mm was drilled through the femoral condyles in male New Zealand rabbits. Collagraft^® with bone marrow harvested from the posterior iliac crest or TricOs T^® with and without bone marrow was introduced into the defect. Rabbits were euthanized 8 weeks later. The percentage of newly formed bone was determined by micro-computed tomography.
Results: There was no significant difference between bone ingrowth at 8 weeks. Thus, TricOs T^® without bone marrow showed similar bone ingrowth as Collagraft^® with bone marrow. Furthermore, no increase of bone ingrowth could be achieved by adding bone marrow to TricOs T^® in the present setting.
Conclusion: Both bone substitutes showed similar bone ingrowth in this investigation. Using TricOs T^® without bone marrow could avoid donor site morbidity due to harvesting of bone marrow. Further prospective clinical trials will be needed to investigate this approach.     

Modulation of osteogenic potential by recombinant human bone morphogenic protein-2 in human periodontal ligament cells: effect of serum, culture medium, and osteoinductive medium

BACKGROUND AND OBJECTIVE: Bone morphogenic proteins are known, in animal models, to promote many developmental processes, including osteogenesis. Clinical trials are currently underway to evaluate the potential of bone morphogenic proteins to promote bone and periodontal regeneration in humans. The aim of this study was to establish an optimal cell culture condition for using to study the biological effects of recombinant human bone morphogenic protein-2 on periodontal ligament cells. MATERIAL AND METHODS: The roles of serum concentration, types of culture medium (alpha-modified essential medium or Dulbecco's modified Eagle's medium), the presence of osteoinductive medium (including dexamethasone, ascorbic acid and beta-glycerophosphate), and timing of addition of the osteoinductive medium and recombinant human bone morphogenic protein-2, on the expression of alkaline phosphatase were investigated in cultured periodontal ligament cells. Cytochemical stainings and biological assay of alkaline phosphatase were also demonstrated. RESULTS: Our results suggested that an increased concentration of serum might mask the effect of recombinant human bone morphogenic protein-2 on the expression of alkaline phosphatase in periodontal ligament cells. alpha-Modified essential medium was found to induce a stronger cytochemical staining of the alkaline phosphatase than Dulbecco's modified Eagle's medium under similar culture conditions. Pre-incubation of cells with osteoinductive medium before the addition of various concentrations of recombinant human bone morphogenic protein-2 enhanced greater alkaline phosphatase expression than the simultaneous presence of both osteoinductive medium and recombinant human bone morphogenic protein-2. CONCLUSION: The findings of this study suggest that the effect of recombinant human bone morphogenic protein-2 on periodontal ligament cells could be efficiently investigated after the proper selection of culture variables and temporal sequence of adding bioactive factors. The optimal culture condition identified in this study might be useful in further studies to elucidate the regulatory mechanism of periodontal ligament cells in periodontal regeneration after stimulation with recombinant human bone morphogenic protein-2.     

Ectopic bone formation after implantation of a slow release system of polylactid acid and rhBMP-2

Objectives: The present study was conducted to test the hypothesis that preshaped polylactic acid (PLA) implants loaded with recombinant human bone morphogenic protein 2 (rhBMP-2) can induce bone formation in a rat ectopic model.
Materials and methods: Two groups of porous cylindrical poly- dl -lactic acid implants of 8-mm diameter were produced by gas foaming with CO₂, incorporating 48 and 96 μg rhBMP-2, respectively, into each implant. Blank PLA implants were used as controls. The release of BMPs and the induction of alkaline phosphatase were assessed in vitro . Osteoinduction in vivo was tested by insertion of 15 implants from each group into the gluteal muscles of Wistar rats. Five implants from each group were retrieved after 6, 13 and 26 weeks and assessed using flat panel volume detector computed tomography and light microscopy.
Results: Both groups of implants showed increased release of rhBMP-2 during the first 24–48 h, with a slightly higher amount being released from the implants with 48 μg. Release during subsequent intervals was <100 ng/72 h in the low-concentration group and >100 ng in the group with 96 μg rhBMP-2. Implants with 95 μg rhBMP-2 exhibited bone formation in vivo on the outside of the implants across the observation period of 26 weeks with invasion of bone into the pores, whereas implants with 48 μg rhBMP-2 failed to induce the formation of bone tissue. No bone formation was found in the control implants.
Conclusions: The results suggest that release rates of rhBMP-2 for ectopic bone induction have to be >100 ng/72 h to maintain the osteoinductive activity of the tested porous PLA implants. This slow release system may have impact on alveolar bone augmentation procedures when used as individually preformed osteoinductive implants.     

Maxillary sinus floor elevation using a tissue-engineered bone complex with OsteoBone and bMSCs in rabbits

Objectives: To evaluate the effects of maxillary sinus floor elevation by a tissue-engineered bone complex with OsteoBone^™ and bone marrow stromal cells (bMSCs) in rabbits.
Material and methods: Autologous bMSCs from adult New Zealand rabbits were cultured and combined with OsteoBone^™ at a concentration of 20 × 10⁶ cells/ml in vitro . Twenty-four animals were used and randomly allocated into groups. For each time point, 16 maxillary sinus floor elevation surgeries were made bilaterally in eight animals and randomly repaired by bMSCs/material (i.e. OsteoBone^™), material, autogenous bone and blood clot ( n =4 per group). A polychrome sequential fluorescent labeling was also performed post-operatively. The animals were sacrificed 2, 4 and 8 weeks after the procedure and evaluated histologically as well as histomorphometrically.
Results: New bone area significantly decreased from weeks 2 to 8 in the blood clot group, while bone area in the autologous bone reduced from weeks 4 to 8. In both groups, a significant amount of fatty tissue appeared at week 8. Accordingly, augmented height in both groups was also significantly decreased from weeks 2 to 8. The bone area in the material-alone group as well as in the bMSCs/material group, on the other hand, increased over time. Significantly more newly formed bone area and mineralization was observed in the center of the raised space in the bMSCs/material group than in the material-alone group. The augmented height was maintained in these two groups throughout the course of this study.
Conclusion: These results suggest that OsteoBone^™ can successfully be used as a bone graft substitute and that the combination of this material with bMSCs can effectively promote new bone formation in sinus elevation.     

Alveolar ridge regeneration with equine spongy bone: a clinical, histological, and immunohistochemical case series

Background: In the case of localized ridge atrophy, a ridge augmentation procedure, with the use of bone substitutes and barrier membranes, may then be necessary.
Purpose: The aim of the present study was a clinical, histological, and immunohistochemical evaluation of an equine spongy bone in alveolar ridge augmentation procedures.
Materials and Methods: Five patients showing horizontal mandibular ridge defects participated in this study. A ridge augmentation was performed through an onlay apposition of equine bone covered by a titanium-reinforced membrane. After 6 months of healing, five bone cores from nonaugmented sites (control) and five from augmented sites (test) were retrieved.
Results: In test sites, no postoperative complications occurred. Horizontal bone width increased from ≤4 to ≥7 mm. In control sites, the newly formed bone represented 33%, and in test sites, 35% of the total area. The mean value of the microvessel density was 25.6 +/– 3.425 per mm² in controls, while 33.3 +/– 2.5 vessels per mm² in the test sites were found ( p  < .05). Both groups showed a high intensity (++) of vascular endothelial growth factor expression in the newly formed bone, while a low intensity (+) was found in the mature bone.
Conclusion: Equine bone appeared to be biocompatible and to be associated with new vessel ingrowth. Within the limits of the small sample size, the present study indicated that equine bone could be used in mandibular ridge augmentations.     

The use of tissue-engineered bone with human bone morphogenetic protein-4-modified bone-marrow stromal cells in repairing mandibular defects in rabbits

In this study, the capacity of hBMP-4 gene therapy combined with tissue-engineering techniques to improve the repair of mandibular osseous defects in rabbits was explored. A mammalian plasmid vector expressing enhanced green fluorescent protein-human bone morphogenetic protein-4 (pEGFP-hBMP-4) was initially constructed through subcloning techniques. Bone-marrow stromal cells (bMSCs) from New Zealand White rabbits were cultured and either transfected with pEGFP-hBMP-4 or pEGFP, or left untransfected in vitro. Once the transfer efficiency was determined through the expression of EGFP, cells from the three groups were combined with natural non-organic bone (NNB) at a concentration of 50 x 10(6)cells/ml and placed in 15 mm x 6 mm bilateral, full-thickness, mandibular defects surgically made in 12 rabbits. Together with NNB control, there were six samples per group. Four weeks after surgery, the implants were harvested and evaluated histomorphologically. Under optimal experimental conditions, gene transfer efficiency reached a maximum of 38.2+/-9.4%. While the percentage of new bone area in the NNB control group was 8.8+/-3.1%, in the untransfected bMSC group 22.5+/-8.2%, and in the pEGFP group 18.1+/-9.0%, a significantly higher amount of 32.5+/-6.1% was observed in the pEGFP-hBMP-4 group. These results suggest that transfection of bMSCs with hBMP-4 enhances their inherent osteogenic capacity for maxillofacial bone tissue-engineering applications.     

组织工程修复区早期牙移动压力侧牙周组织的改建

目的: 探讨牙槽骨组织工程修复区内早期牙移动时压力侧的牙周改建情况,为组织工程技术在正畸中应用的安全性和可行性提供实验依据。方法: 选取30只新西兰大白兔,通过拔除下颌第一磨牙并扩大拔牙窝,建立双侧牙槽骨的超临界骨缺损,分别以实验组骨髓间充质干细胞（bone marrow mesenchymal stem cells,BMSCs）与颗粒型多孔β磷酸三钙（beta-tricalcium phosphate,β-TCP）支架复合构成的组织工程骨和对照组单纯β-TCP支架进行右侧和左侧骨缺损修复。术后8周,选取6只兔进行植骨区取材,评价2组的成骨效果。对剩余兔进行下颌两侧第二磨牙加力,近中向牵引4周。分别在加力后的第1、2、3、4周各处死6只动物,测量牙移动距离并制作组织学切片,通过H-E染色观察牙周组织变化,抗酒石酸酸性磷酸酶染色法计数压力侧破骨细胞数目。采用SPSS 19.0软件包对数据进行统计学分析。结果: 植骨术后8周,实验组成骨效果优于对照组。牵引4周后,正畸牙在实验组牙槽骨修复区内的移动量大于对照组。牵引第2、3、4周时,实验组移动牙压力侧的破骨细胞数量均高于对照组,差异具有统计学意义。结论: BMSCs复合β-TCP支架能够良好地修复牙槽骨缺损,邻牙在组织工程修复区内早期移动时,再生的牙周组织改建活跃,有加速牙移动的趋势。     

Simvastatin therapy in cyclosporine A-induced alveolar bone loss in rats

Background and Objective:  Cyclosporine A treatment is important in the therapy of a number of medical conditions; however, alveolar bone loss is an important negative side-effect of this drug. As such, we evaluated whether concomitant administration of simvastatin would minimize cyclosporine A-associated alveolar bone loss in rats subjected, or not, to experimental periodontal disease.
Material and Methods:  Groups of 10 rats each were treated with cyclosporine A (10 mg/kg/day), simvastatin (20 mg/kg/day), cyclosporine A and simvastatin concurrently (cyclosporine A/simvastatin) or vehicle for 30 days. Four other groups of 10 rats each received a cotton ligature around the lower first molar and were treated similarly with cyclosporine A, simvastatin, cyclosporine A/simvastatin or vehicle. Calcium (Ca²⁺), phosphorus and alkaline phosphatase levels were evaluated in serum. Expression levels of interleukin-1β, prostaglandin E₂ and inducible nitric oxide synthase were evaluated in the gingivomucosal tissues. Bone volume and numbers of osteoblasts and osteoclasts were also analyzed.
Results:  Treatment with cyclosporine A in rats, with or without ligature, was associated with bone loss, represented by a lower bone volume and an increase in the number of osteoclasts. Treatment with cyclosporine A was associated with bone resorption, whereas simvastatin treatment improved cyclosporine A-associated alveolar bone loss in all parameters studied. In addition, simvastatin, in the presence of inflammation, can act as an anti-inflammatory agent.
Conclusion:  This study shows that simvastatin therapy leads to a reversal of the cyclosporine A-induced bone loss, which may be mediated by downregulation of interleukin-1β and prostaglandin E₂ production.     

Relation of bone turnover markers to periodontal disease and jaw bone morphology in elderly Japanese subjects

Objective:  The purpose of this study was to evaluate the relation of bone turnover markers such as bone formation and resorption to periodontal disease and jaw bone morphology in elderly Japanese subjects.
Subjects and methods:  We selected 148 subjects for participation in this study. All subjects were aged 77 years. The periodontal examination included the assessment of clinical attachment level (CAL). Biochemical parameters of bone turnover measured included urinary deoxypyridinoline, serum osteocalcin (S-OC), and serum bone-specific alkaline phosphatase. In addition, to evaluate the jawbone, we used the mandibular inferior cortex classification (MIC).
Results:  Serum osteocalcin had significantly higher (males: P  =   0.038, females: P  =   0.041) tendency for MIC Class (ANOVA). Multiple linear regression results showed that the number of remaining teeth and S-OC were negatively associated with the percentage of sites with ≥6 mm CAL ( R ² = 0.322, P  < 0.001). Coefficients and betas were −0.71, −0.46 ( P  <   0.001) and −1.11, −0.28 ( P  =   0.002), respectively.
Conclusion:  In conclusion, this study suggests that there is a significant relation of bone turnover markers to periodontal disease and jaw bone morphology in elderly Japanese subjects.     

SHED repair critical-size calvarial defects in mice

Objective:  Stem cells from human exfoliated deciduous teeth (SHED) are a population of highly proliferative postnatal stem cells capable of differentiating into odontoblasts, adipocytes, neural cells, and osteo-inductive cells. To examine whether SHED-mediated bone regeneration can be utilized for therapeutic purposes, we used SHED to repair critical-size calvarial defects in immunocompromised mice.
Materials and methods:  We generated calvarial defects and transplanted SHED with hydroxyapatite/tricalcium phosphate as a carrier into the defect areas.
Results:  SHED were able to repair the defects with substantial bone formation. Interestingly, SHED-mediated osteogenesis failed to recruit hematopoietic marrow elements that are commonly seen in bone marrow mesenchymal stem cell-generated bone. Furthermore, SHED were found to co-express mesenchymal stem cell marker, CC9/MUC18/CD146, with an array of growth factor receptors such as transforming growth factor β receptor I and II, fibroblast growth factor receptor I and III, and vascular endothelial growth factor receptor I, implying their comprehensive differentiation potential.
Conclusions:  Our data indicate that SHED, derived from neural crest cells, may select unique mechanisms to exert osteogenesis. SHED might be a suitable resource for orofacial bone regeneration.     

A randomized-controlled clinical trial evaluating clinical and radiological outcomes after 3 and 5 years of dental implants placed in bone regenerated by means of GBR techniques with or without the addition of BMP-2

Objective: The aim of this randomized-controlled clinical trial was to evaluate the long-term outcome of implants placed in bone augmented with a xenogenic bone substitute material and a collagen membrane with or without the addition of recombinant human bone morphogenetic protein-2 (rhBMP-2).
Material and methods: Eleven patients received a total of 34 implants placed into sites exhibiting lateral bone defects. In a split mouth design, the defects were randomly treated with the graft material and the collagen membrane either with (test) or without (control) rhBMP-2. The patients were examined 3 and 5 years after insertion of the prosthetic restoration. Student's paired t -test was performed to detect differences between the two groups.
Results: The survival rate at 3 and 5 years was 100% for both groups. The peri-implant soft tissues were stable and healthy without any difference between the two groups. The prosthetic reevaluation demonstrated four loose prosthetic screws during the first 3 years and seven ceramic chippings after 3 and 5 years. The mean distance between the first bone to implant contact to implant abutment junction at 3 years was 1.37 mm (test), 1.22 mm (control), and 1.38 mm (test), and 1.23 mm (control) at 5 years. The difference of <0.2 mm between test and control implants was not statistically significant. The mean change of the marginal bone level between baseline and 5 years ranged from −0.07 mm (mesial, test), −0.11 mm (distal, test), −0.03 mm (mesial, control), to +0.13 mm (distal, control). No statistically significant differences were observed between test and control sites.
Conclusion: Implants placed in bone augmented with and without rhBMP-2 revealed excellent clinical and radiological outcomes after 3 and 5 years.     

CS/β-TCP/rhBMP-2复合因子加血管束修复兔下颌骨缺损的实验研究

目的:通过研究在壳聚糖(CS)/β-磷酸三钙(β-TCP)复合体修复兔下颌骨缺损的过程中,探讨重组人骨形态发生蛋白-2(rhBMP-2)及兔面动脉血管束对成骨作用的影响,探讨CS/β-TCP/rhBMP-2+复合因子血管束修复骨缺损的可行性。方法:健康新西兰大白兔36只共36侧骨缺损(全部为左侧),随机分为3组。实验组在缺损区植入CS/β-TCP复合体,加入rhBMP-2,同时包埋兔面动脉及下颌下腺包膜组成的血管束;对照1组缺损区植入CS/β-TCP复合体,只加入rhBMP-2;对照2组缺损区植入CS/β-TCP复合体,并包埋兔面动脉及下颌下腺包膜组成的血管束,不加入rhBMP-2。于术后4周、8周、12周分批处死动物,取材后行大体观察、X线、组织切片染色观察及骨密度测定,观察各组的成骨情况。采用SPSS13.0软件包进行组间比较。结果:实验组在术后8、12周的骨密度值均显著高于对照组(P<0.05)。术后12周,实验组取材后大体观察,植入材料区皮质骨形成完好,与自体骨组织分界肉眼难辨别,X线表现较正常骨质已无明显差异,HE染色可见丰富成熟的骨小梁及板层骨,各项指标均显著优于对照组。结论:CS/β-TCP复合体修复兔下颌骨缺损过程中,加入rhBMP-2并包埋进兔面动脉血管束可明显促进成骨作用。