Reconstruction of critical size calvarial bone defects in rabbits with glass-fiber-reinforced composite with bioactive glass granule coating

The aim of this study was to evaluate glass-fiber-reinforced composite as a bone reconstruction material in the critical size defects in rabbit calvarial bones. The bone defect healing process and inflammatory reactions were evaluated histologically at 4 and 12 weeks postoperatively. Possible neuropathological effects on brain tissue were evaluated. The release of residual monomers from the fiber-reinforced composite (FRC) was analyzed by high performance liquid chromatograph (HPLC). RESULTS: At 4 weeks postoperatively, fibrous connective tissue ingrowth to implant structures was seen. Healing had started as new bone formation from defect margins, as well as woven bone islets in the middle of the defect. Woven bone was also seen inside the implant. Inflammation reaction was slight. At 12 weeks, part of the new bone had matured to lamellar-type, and inflammation reaction was slight to moderate. Control defects had healed by fibrous connective tissue. Histological examinations of the brain revealed no obvious damage to brain morphology. In HPLC analysis, the release of residual 1,4-butanedioldimethacrylate and methylmethacrylate from polymerized FRC was low. CONCLUSIONS: This FRC-implant was shown to promote the healing process of critical size calvarial bone defect in rabbits. After some modifications to the material properties, this type of implant has the potential to become an alternative for the reconstruction of bone defects in the head and neck area in the future.     

Increased new bone formation with a surface magnesium-incorporated deproteinized porcine bone substitute in rabbit calvarial defects

This study investigated the effects of magnesium ion (Mg) incorporation into the surface of deproteinized porcine cancellous bone in the bone healing of rabbit calvarial defects with the expectation of utilizing the integrin-ligand binding enhancement effect of Mg, and compared its bone healing capacity with that of untreated porcine cancellous bone and deproteinized bovine bone (Bio-Oss). Hydrothermal treatment was performed to produce Mg-incorporated porcine bone using an alkaline Mg-containing solution. The surface morphology and chemical composition of the samples were investigated using scanning electron microscopy, energy-dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Defects 7 mm in diameter were created in the calvaria of 14 adult male New Zealand White rabbits and were filled with (1) untreated porcine bone (PB), (2) Bio-Oss, and (3) Mg-containing porcine bone (MG). The percentage of newly formed bone (NB%) was evaluated histomorphometrically at 2 and 4 weeks after implantation. Hydrothermal treatment resulted in a Mg-containing surface in porcine bone covered with nanostructures ~100 nm in size. The MG group supported better new bone formation compared with the other groups. Osteoconductive new bone formation was observed in the central defect area in the MG group at an early healing time-point. Histomorphometric analysis revealed significantly greater NB% in the MG group when compared with the untreated PB and Bio-Oss groups at 4 weeks (p < 0.05). The Mg-incorporated porcine bone with surface nanostructures achieved rapid new bone formation in the osseous defects of rabbit calvaria compared with untreated xenografts of porcine and bovine origin.     

Frontal bone defect repair with experimental glass-fiber-reinforced composite with bioactive glass granule coating

OBJECTIVE: The aim of this preliminary study was to test the bioactive glass-coated fiber-reinforced composite (FRC) as a reconstruction material in the treatment of experimental defects in the frontal bone of rabbits. METHODS: FRC made of E-glass fiber and BisGMA-PMMA resin matrix system was used in the study. Pieces of nonpolymerized FRC were coated with particulate bioactive glass granules S53P4 (BAG), and then the FRC was polymerized and post-cured by heat in air to reduce the quantity of residual monomers, and to sterilize the material for the animal study. Two round defects (5 mm in diameter) were drilled in the upper bony walls of 12 NZW rabbits' frontal sinuses, and rectangular FRC plates were applied over the defects. In the control group, no FRC plates were used. The bone defect healing process was evaluated on histological sections at 3, 6, and 8 weeks, postoperatively. SEM-EDX analysis was used to determine reactive layers of bioactive glass granules. RESULTS: The healing progressed from the fibroconnective tissue phase at 3 weeks to lamellar bone formation at 6 and 8 weeks. The difference in new bone formation between the implantation groups and control groups was not statistically significant, although in some animals the effect of the implant on bone healing was clearly positive. A moderate foreign body reaction was seen on the implant surface where BAG granules did not uniformly cover the implant's polymer matrix. CONCLUSIONS: This study suggests that the tested FRC implant with bioactive glass coating provides an alternative for bone defect reconstruction. However, more research on this composite material and its biocompatibility is needed.     

Evaluation of bone regeneration at critical-sized calvarial defect by DBM/AM composite

This study investigated the bone-regenerative potential of a demineralized bone and acellular matrix (DBM/AM) composite (AlloCraft DBM) in comparison with autologous bone using an in vivo model. Critical-sized calvarial defects (5 mm) were created in athymic rats. The defects were grafted with either the DBM/AM composite or the acellular human dermal matrix (AM), and compared with the defects filled with autologous bone (positive control) and the empty defect (negative control). Histological and radiographic assessments were carried out at 4 and 8 weeks after surgery to determine the biological healing, the amount and type of new bone formation and the percentage of new bone filled in the critical defects. At 4 weeks, DBM/AM composite group had the highest percentage of the defect filled with new bone (84%), which was significantly greater than autologous bone (62%), AM (41%), and untreated control (32%) groups. At 8 weeks, the DBM/AM continued to have the highest percentage of the defect filled with new bone (91%). The autologous bone group increased the percentage of bone fill to 83%. The defects either filled with AM or left untreated still had less of the defect filled with new bone, 57% and 33%, respectively. The total healing of defects grafted with DBM/AM was comparable with autologous bone group at 8 weeks. The results demonstrated that the DBM/AM composite promoted new bone formation more rapidly than autologous bone at calvarial defect in athymic rats. The study supports that DBM/AM is a potential substitute of autologous bone for bone repair.     

Reconstruction of calvarial bone defects using poly(amino acid)/hydroxyapatite/calcium sulfate composite

The aim of this study was to evaluate the thermal properties and in vivo interface performance of poly(amino acid) (PAA) and a composite containing PAA, hydroxyapatite (HA), and calcium sulfate (CS), with respect to their suitability for skull repair. Biocompatibility was evaluated by implantation of materials into muscles of rabbits for eight weeks. Skull repair was assessed by implanting PAA, the compact PAA/HA/CS composite (c-PAA/HA/CS), and a one-side-porous PAA/HA/CS composite (p-PAA/HA/CS) into rabbit calvarial defects. The results showed that the PAA/HA/CS composite possessed good heat resistance and possessed excellent biocompatibility and osteoconductivity. Guided bone regeneration and calvarial repair were observed, with excellent integration between calvarial tissue and implant. The p-PAA/HA/CS composite performed best in terms of stability and bone bonding between implant and host bone tissue. Thus, the present work provides new information for the potential use of osteoconductive PAA/HA/CS composites with a macrostructure in calvarial bone repair.     

Initial adhesion and surface growth of Staphylococcus epidermidis and Pseudomonas aeruginosa on biomedical polymers

The infection risk of biomaterials implants varies between different materials and is determined by an interplay of adhesion and surface growth of the infecting organisms. In this study, we compared initial adhesion and surface growth of Staphylococcus epidermidis HBH(2) 102 and Pseudomonas aeruginosa AK1 on poly(dimethylsiloxane), Teflon, polyethylene, polypropylene, polyurethane, poly(ethylene terephthalate), poly(methyl methacrylate), and glass. Initial adhesion was measured in situ in a parallel plate flow chamber with microorganisms suspended in phosphate-buffered saline, while subsequent surface growth was followed in full and in 20 times diluted growth medium. Initial adhesion of both bacterial strains was similar to all biomaterials. In full growth medium, generation times of surface growing S. epidermidis ranged from 17 to 38 min with no relation to wettability, while in diluted growth medium generation times increased from 44 to 98 min with increasing surface wettability. For P. aeruginosa no influence of surface wettability on generation times was observed, but generation times increased with decreasing desorption rates, maximal generation times being 47 min and minimal values down to 30 min. Generally, generation times of adhering bacteria were shorter than of planktonic bacteria. In conclusion, surface growth of initially adhering bacteria is influenced by biomaterials surface properties to a greater extent than initial adhesion.     

Tissue-engineered bone biomimetic to regenerate calvarial critical-sized defects in athymic rats.

A tissue-engineered bone biomimetic device was developed to regenerate calvaria critical-sized defects (CSDs) in athymic rats. Well-documented evidence clearly confirms that left untreated, CSDs will not spontaneously regenerate bone. To accomplish regeneration, four candidate treatments were assessed: porous poly(D,L-lactide) and type I collagen (PLC), PLC and human osteoblast precursor cells (OPCs) at 2 x 10(5) (PLC/OPCs), PLC and 50 microg of recombinant human bone morphogenetic protein-2 (PLC/rhBMP-2), and PLC/OPCs/rhBMP-2 (the bone biomimetic device). The hypotheses for this study were PLC/OPCs/rhBMP-2 would promote more new bone formation in CSDs than the other treatments and the amount of bone formation would be time dependent. To test the hypotheses, outcomes from treatments were measured at 2 and 4 weeks postoperatively by radiomorphometry for percent radiopacity and by histomorphometry for square millimeters of new bone formation. Data were analyzed by analysis of variance and Fisher's protected least significant difference for multiple comparisons with p < or = 0.05. At 2 and 4 weeks, radiomorphometric data revealed PLC/rhBMP-2 and PLC/OPCs/rhBMP-2 promoted significantly more radiopacity than either PLC or PLC/OPCs. Histomorphometry data at 2 and 4 weeks indicated significantly more new bone formation for PLC/rhBMP-2, PLC/OPCs/rhBMP-2, and PLC/OPCs compared to PLC. By 4 weeks, PLC/OPCs/rhBMP-2 and PLC/rhBMP-2 had regenerated the CSDs with more new bone than the other treatments; the quantity of bone at 4 weeks for these treatments was greater than at 2 weeks.     

煅烧骨/壳聚糖复合材料对成骨细胞增殖黏附的影响

文题释义：壳聚糖：是甲壳素的脱乙酰产物,属于天然聚合物,广泛存在于低等生物体内,其代谢产物为N-乙酰葡萄糖和氨基多糖,是天然代谢产物,对人体组织无毒无害,具有良好的生物相容性和生物降解性。 体外细胞毒性实验：是运用体外细胞培养技术检测待测物质和(或)其浸提液是否造成细胞生长受到抑制、变异、溶解、死亡等情况,是生物材料评价体系中非常重要的指标之一,也是各种生物材料运用到临床前安全性评价的必选和首选项目。背景：前期研究制备了不同配比的煅烧骨/壳聚糖复合材料,体外细胞实验显示该复合材料安全无毒。目的：观察煅烧骨/壳聚糖复合材料对成骨细胞增殖与黏附的影响。方法：采用溶液共混法制备煅烧骨与壳聚糖质量比分别为1/2、1/1、2/1的复合材料,将新生大鼠成骨细胞分别接种于3种复合材料上,以单独培养的细胞为对照。采用CCK-8法检测细胞增殖情况,DAPI荧光染色观察细胞在材料上的生长情况,扫描电镜观察细胞在复合材料表面的黏附。 结果与结论：①CCK-8检测显示4组成骨细胞增殖良好,在培养的第1-3天增殖较慢,第3天后增殖加快,第3-7天进入对数生长期,第7天后进入平台期,复合材料组细胞增殖与对照组无差异;②培养3 d后的DAPI荧光染色显示,成骨细胞在3种复合材料表面生长良好,组间无明显差异;③扫描电镜显示,培养3 d后成骨细胞紧密黏附于3种复合材料表面,伸展完全,胞体丰满并伸出伪足嵌入材料内部;培养7 d后细胞铺满材料表面,生长密集,其中质量比为2/1煅烧骨/壳聚糖复合材料表面的细胞最密集;④结果表明,成骨细胞可在煅烧骨/壳聚糖复合材料表面增殖与黏附。ORCID: 0000-0003-3519-4485(廖健) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

精氨酸甘氨酸天冬氨酸多肽表面修饰促进生物支架材料对骨髓来源 种子细胞的黏附

背景：精氨酸甘氨酸天冬氨酸多肽具有较强的黏附性和生物支架材料可接枝结合,且不会改变材料的表面理化性质。 目的：观察应用精氨酸甘氨酸天冬氨酸多肽表面修饰猪主动脉瓣去细胞支架材料对骨髓干细胞黏附性的影响。 方法：采用胰蛋白酶+TritonX-100法制备猪主动脉瓣去细胞支架材料,用YGRGDSP多肽(酪氨酸-甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸-脯氨酸)进行处理,按照精氨酸甘氨酸天冬氨酸多肽的质量浓度(0.5,1.0,1.5,2.0 g/L)、反应时间(4,8,12,24 h)、反应pH值(7.0,7.4,8.0)分为不同实验组。 结果与结论：茚三酮显示精氨酸甘氨酸天冬氨酸多肽可很好的交联到猪主动脉瓣去细胞支架材料,最佳反应条件为：室温、1.5 g/L精氨酸甘氨酸天冬氨酸、pH 7.4、持续振荡12 h。提示利用YGRGDSP多肽对猪主动脉瓣去细胞支架材料进行表面修饰可显著改善骨髓来源种子细胞的黏附性。     

Avian tenascin-W: expression in smooth muscle and bone, and effects on calvarial cell spreading and adhesion in vitro.

Tenascins are glycoproteins found primarily in the embryonic extracellular matrix. Here we have characterized the fourth and final member of the tenascin family in birds: tenascin-W. Avian tenascin-W has 3.5 epidermal growth factor-like repeats, 6 fibronectin type III domains, and a C-terminal fibrinogen-related domain. Immunohistochemistry reveals that avian tenascin-W is expressed transiently in developing smooth muscle, tendons, and ligaments, but the primary site of tenascin-W expression during development is in the extracellular matrix of bone and the cellular periosteum. In bony matrix, tenascin-W-coated fibrils partly overlap with fibrils that contain tenascin-C. The anti-tenascin-W also labels fibrils in cultures of osteogenic embryonic chicken calvarial cells. Primary calvarial cells cultured on purified tenascin-W become rounded, and fewer of these cells spread on fibronectin when tenascin-W is added to the medium when compared with calvarial cells cultured on fibronectin alone. Moreover, tenascin-W reduces the adhesion of calvarial cells to collagen type I in a shear force assay. We conclude that tenascin-W is likely to play a phylogenetically conserved role in developing bone and that it shares some of the basic anti-adhesive and matrix modulatory properties as tenascin-C.     

Structural differences between bone formed intramuscularly following the transplantation of isolated calvarial bone cells or chondrocytes

Summary Bone formed in intramuscular transplants of isolated syngeneic calvarial bone cells in mice, was compared with endochondral bone induced by cartilage produced by analogous transplants of isolated epiphyseal chondrocytes, as well as with parietal bones forming the bulk of the calvaria. Transplanted calvarial cells produced islands of bone, some of which contained intraosseous cavities. Osteoclasts inside these cavities were observed only in 14-day-old transplants and bone marrow cells in 28-day and older transplants. On the contrary, bone marrow appeared soon after formation of bone trabeculae in endochondral bone. The percentage area occupied by bone marrow in these specimens was about twentyfold larger than in the bone formed by transplanted bone cells. On the other hand, the bone marrow area in the latter type of bone was somewhat smaller but of similar order as in parietal bones. Moreover, both in parietal bones and in bone formed by isolated bone cells, the bone marrow was devoid of fat cells which were numerous in bone arising by endochondral ossification. It appears, therefore, that the ratio of bone marrow to the bone tissue area in parietal bones depends more on the intrinsic properties of osteoblasts than on the local factors in the environment of the developing bone. In the case of bone induced by cartilage, the bone marrow/bone tissue area could be determined both by the extent of cartilage resorption by vascularized tissue and by the properties of osteoblasts.     

The improvement of calvarial bone healing by durable nanogel-crosslinked materials

Abstract

Different approaches have been developed to improve the scaffold properties that provide structural support and biological interaction to achieve the desired environment for tissue regeneration. We previously reported that addition of human fibroblast growth factor 18 (hFGF18) to acryloyl group-modified cholesterol-bearing pullulan (CHPOA) nanogel-crosslinked (NanoClik) hydrogels that contain human bone morphogenetic protein 2 (hBMP2) stabilized bone healing in mouse calvarial defect model. In this study, we evaluated the use of disc-shaped dried nanogel-crosslinked gel as carriers of growth factors in order to seek possible clinical application in future. Both conventionally-dried NanoClik disc and nanogel-crosslinked porous (NanoCliP) disc made by freeze-drying that contained the growth factors induced bone healing but not as much as with NanoClik hydrogel application but addition of RGD peptides (RGD-NanoCliP disc) improved the healing. All type of discs showed the same biphasic ovalbumin-Alexa Fluor 488 protein release profile in vitro, an initial burst followed by a gradual sustained release more than one week, which was confirmed in vivo. Histological analysis showed remarkable new bone formation with more calcification in RGD-NanoCliP disc with the growth factors and the osteogenesis appeared to begin in the dura mater in contact with the disc. These observations suggest: (1) the fitness of the durable discs to the bone defect is a critical factor for bone healing, which is supplemented by addition of RGD peptides, (2) the porosity is suitable for osteoblast recruitment, (3) growth factor release pattern of the CHPOA nanogel based gels is ideal for bone healing.     

Laminin-apatite composite coating to enhance cell adhesion to ethylene-vinyl alcohol copolymer

A laminin-apatite composite layer with enhanced cell adhesive properties was successfully formed on the surface of an ethylene-vinyl alcohol copolymer (EVOH) by a liquid phase coating process. The coating process was carried out with the following procedure. First, an EVOH plate was alternately dipped in 200 mM calcium and 200 mM phosphate solutions to introduce nuclei or precursors of apatite to its surface. Second, the surface-modified EVOH was immersed in a calcium phosphate solution, which was supersaturated with respect to apatite and containing laminin. As a result of this procedure, a laminin-apatite composite layer with a thickness of 2.5-3.0 microm was formed on the EVOH surface. Epithelial-like cells (BSCC93) adhered to the laminin-apatite composite layer showed enhanced cell spreading, which was due to the biological effect of laminin. The number of cells adhered to the laminin-apatite composite layer on EVOH was approximately 10 times as large as that adhered to the surface of the untreated, laminin-adsorbed, or apatite-coated EVOH. Therefore, this type of composite material consisting of a synthetic polymer, apatite, and laminin has great potential as a skin terminal, with improved adhesiveness to skin tissue, as well as good biocompatibility.     

适当质量浓度黄芪注射液可增强骨髓基质细胞的表面黏附性

背景：研究发现很多益气补血类中药均是通过影响骨髓基质细胞分泌一些细胞因子来促进造血干细胞的分化增殖,或者促进骨髓基质细胞和造血干细胞的黏附而发挥作用。目的：观察黄芪注射液对小鼠骨髓基质细胞表面细胞间黏附分子1、血管细胞间黏附分子1表达的影响。方法：采用全骨髓贴壁细胞分离筛选法培养小鼠骨髓基质细胞,倒置相差显微镜、苏木精-伊红染色光镜及透射电镜观察小鼠骨髓基质细胞的形态。MTT法检测黄芪注射液促进骨髓基质细胞增殖的最佳浓度。流式细胞术检测黄芪注射液干预后小鼠骨髓基质细胞表面细胞间黏附分子1、血管细胞间黏附分子1的表达。结果与结论：倒置显微镜和光镜观察到骨髓基质细胞呈贴壁生长,细胞呈梭形或不规则形态,有突起;透射电镜观察到细胞内细胞器丰富,如粗面内质网、分泌小泡、线粒体等。黄芪注射液质量浓度为400和600 mg/L时可促进小鼠骨髓基质细胞增殖(P < 0.05),且两种剂量组间比较差异无显著性意义。600 mg/L黄芪注射液可增加小鼠骨髓基质细胞表面细胞间黏附分子1、血管细胞间黏附分子1蛋白表达。结果表明适当质量浓度黄芪注射液能够增强基质细胞的黏附性,对造血微环境有改善作用。 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

Reconstruction of calvarial defect using a tricalcium phosphate-oligomeric proanthocyanidins cross-linked gelatin composite

A biodegradable GTP composite which was composed of oligomeric proanthocyanidins (OPCs) cross-linked gelatin mixed with tricalcium phosphate was developed as a bone substitute. The subcutaneous implantation in rats was examined to determine the in vivo degradation and biocompatibility of the GTP composites with various cross-linking densities. Experimental results indicated that the rate of in vivo degradation was markedly attenuated as the concentration of OPCs increased above 5.0 wt%. Furthermore, this study examined the biological response of rabbit calvarial bone to GTP composite to evaluate its potential for use as an osteoconductive bone substitute. Bone defects (10 mm in diameter) in New Zealand white rabbits were filled with the GTP composite. The de-protenized bovine cancellous bone matrix was employed as the control material. The results of radiographic analyses demonstrated obviously greater new bone ingrowth in the GTP composite than in the de-proteinized bovine bone at the same implantation time. Progressive replacement of the GTP composite by new bone proceeded by a combination of osteoconduction and biodegradation. The biodegradable GTP composite thus has great potential for improving bone repair.     

柚皮甙干预鼠颅顶骨破骨细胞的形成及功能

背景：柚皮甙能诱导骨形态发生蛋白2的基因表达,促进成骨细胞系的增殖和分化。体外细胞实验提示柚皮甙有抑制破骨细胞的形成及抗骨质疏松的作用。 目的：建立含有柚皮甙的鼠颅顶骨培养模型,观察不同剂量下柚皮甙对破骨细胞增殖分化的影响。 方法：实验选取出生4 d的SD乳鼠颅顶骨,在分别含有0,1,10,100 mg/L 的柚皮甙的培养基中培养,于培养的第1,3,7,10天测定柚皮甙对鼠颅顶骨中破骨细胞标志酶抗酒石酸酸性磷酸酶阳性细胞数及培养基中钙离子浓度的影响。 结果与结论：第1天各组间抗酒石酸酸性磷酸酶阳性细胞数及培养基中钙离子浓度无明显变化,第3,7天各组间抗酒石酸酸性磷酸酶阳性细胞数随柚皮甙质量浓度增加而减少,而培养基中钙离子浓度变化明显增加,到第10天这种变化趋势最为明显。说明柚皮甙能影响鼠颅顶骨中抗酒石酸酸性磷酸酶阳性细胞数量及其功能,并且这种作用成明显的时间剂量相关性。提示柚皮甙不仅能促进成骨细胞的增殖,同时也能减少破骨细胞的分化或加速其凋亡。     

Interpretation of difficulties in the initial adhesion of bio-active glasses to bone

The authors propose a model to explain the initial difficulties in achieving adhesion between bio-active glasses and bone. It is explained that in vitro tests involve biophysical situations which are different, and in many cases very different, from those which take place in in vivo implantation. The model suggests procedures which could be applied to bio-active glasses after the manufacturing process in order to improve their initial adhesion to bone.     

Osteoblast and osteoclast precursors in primary cultures of calvarial bone cells

Bone cells obtained by digestion of fetal mouse or chicken calvaria were tested for their ability to form or resorb bone in vitro. The isolated cells were precultured for 6 days and subsequently cocultured for 11 days with periosteum-free noninvaded fetal mouse long bone rudiments. Bone formation and resorption during coculture were evaluated by histology and 45Ca release from prelabeled bones. The calvarial origin of cells in cocultures was traced by labeling the cells with 3H-thymidine before coculture, followed by autoradiography. Many osteoblasts and osteoclasts as well as fibroblasts developed from mouse periosteal cells released late in the sequential digestion procedure and previously denoted as "osteoblastlike" (BL). No or few osteoblasts and osteoclasts but many fibroblasts developed from early released cell fractions that have previously been denoted as "osteoclastlike" (CL). Only osteoblasts and fibroblasts but not osteoclasts developed from chicken calvarial cell fractions. The osteoblasts developed primarily from cell fractions from the inner layer of the periosteum, previously denoted as "osteoblastlike" (OB). Cells obtained from the outer layer of the periosteum (PF) gave rise mainly to fibroblasts. These studies show that osteoblast and osteoclast precursor cells are maintained in monolayer cultures of periosteal cell fractions. However, sequential digestion of mouse calvaria does not lead to separation of the two types of bone cells. Rather, osteoclast and osteoblast precursors are released jointly, from the periosteal cell layers closest to the bone surface. In the chicken cell fractions osteoclast precursors are absent after preculture, resulting in a more homogeneous population of osteoblast and fibroblast but not osteoclast precursors.     

Bioluminescence imaging of calvarial bone repair using bone marrow and adipose tissue-derived mesenchymal stem cells

A combined strategy using bioluminescence imaging, bone densitometry and histology was used to analyze the bone regeneration capacity of human bone marrow (hBMSC) and adipose tissue (hAMSC) mesenchymal stem cells, seeded in an osteoconductive arginine-glycine-aspartate (RGD) crosslinked hydrogel scaffold, implanted in a mouse calvarial bone defect. We show that firefly luciferase labeled stem cells can be monitored in vivo through a prolonged 90 days period, during which hBMSCs survive better than hAMSCs and that the density of scaffold bearing defects increased significantly more than that of defects without scaffolds.