rhBMP-2和FGF-2对成骨细胞矿化及ENPP1、ANK、TNAP表达的影响

目的:研究重组人骨形态发生蛋白(rhBMP-2)和重组人碱性成纤维细胞生长因子(FGF-2)对成骨细胞(MC3T3-E1 Subclone 14)矿化及焦磷酸合成酶(ENPP1)、跨膜蛋白(ANK)和组织非特异性碱性磷酸酶(TNAP)表达的影响,探讨生长因子影响细胞矿化的机制。方法:将MC3T3-E1 Subclone 14细胞分成3组:成骨细胞诱导液(OS)成骨诱导培养组(对照组),OS与rhBMP-2培养组(rhBMP-2组),OS与FGF-2培养组(FGF-2组)。培养12 d后进行ALP活性检测及茜素红染色,实时荧光定量PCR检测矿化相关基因ENPP1、ANK和TNAP表达的差异。结果:rhBMP-2组ALP活性以及钙化结节明显高于对照组,ENPP1、ANK和TNAP均高表达;FGF-2组ALP活性以及钙化结节明显低于对照组,ENPP1和ANK呈高表达,TNAP低表达。结论:rhBMP-2和FGF-2通过调节ENPP1、ANK和TNAP的表达变化来影响骨的矿化。     

MBL2, MASP2, AMELX, and ENAM gene polymorphisms and dental caries in Polish children

Oral Diseases (2012) 18 , 389–395 Objective: The aim of the study was to examine whether the MBL2 C(‐290)G and G161A, MASP2 A359G, AMELX C287T and C522T, and ENAM C2452T polymorphisms are associated with dental caries. Subjects and methods: Genomic DNA of 95 Polish children with ‘higher caries experience’ (HC) and 84 subjects with ‘lower caries experience’ (LC) belonging to two age‐groups (5 and 13 years old) was extracted from the buccal mucosa. SNPs were genotyped with PCR‐RFLP methods. Results: Among 5‐year‐old children, we found significantly higher percentage of subjects carrying MBL2 (‐290)G allele in HC group compared with LC group (43.2%vs 17.6%, P = 0.023). MBL2 C(‐290)G–G161A C–G haplotype was overrepresented in LC group in 5‐year‐olds (P = 0.01), while the opposite association was observed in 13‐year‐olds, where C–G was overrepresented in HC group (P = 0.028). In 5‐year‐old children, the frequency of MBL2 G–G haplotype was higher in HC group compared with LC subjects (P = 0.045), while the opposite association (with borderline significance) was observed in 13‐year‐old children (P = 0.057). SNPs in MASP2, AMELX, and ENAM were not associated with dental caries. Conclusion: MBL2 gene polymorphism is associated with caries experience in Polish children, but the direction of this association seems to be opposite in primary and permanent dentition.     

可注射型热触发仿天然骨材料的基础研究

目的：试图研制可注射型热敏仿天然骨材料,测定其理化特性,并将其初步应用于体外根尖孔破坏的离体牙模型上。方法：采用逆向蒸发法制备载碱性磷酸酶（alkalinephosphatase,ALP）的脂质体,考察其包封率、活性率及相变温度。将载ALP、载钙离子（Ca^24）和磷酸盐（Pi）3种脂质体与β-甘油磷酸盐（β-glycerophosphate,β-GP）混合制备矿化液,观测矿物质的形态、元素分析及红外光谱曲线;将I型胶原与以上矿化液混合制备的复合材料应用于根尖孔破坏的离体牙根尖周围,根管充填并统计分析。结果：载ALP的脂质体平均包封率为25．1％,平均活性率为16．5％,相变温度为37．3～40．1℃,峰值为39．2℃;与未加ALP者相比,所得矿化物形态和Ca／Pi比与天然骨中矿化物更接近,红外光谱曲线表明其为羟基磷灰石;体外模型显示该复合材料可在一定程度上支托根充材料,预防超充。     

重组人细胞外基质磷酸化糖蛋白对人牙髓细胞体外矿化的影响

目的:探讨细胞外基质磷酸化糖蛋白(Matrix extracellular phosphogl ycoprotein,MEPE)对人牙髓细胞(human dental pulpcells,HDPCs)在体外的矿化能力的影响,从而了解该蛋白在牙齿生长发育过程中的作用。方法:常规方法培养获得人牙髓细胞,实验组中使用的MEPEs的浓度为100μg/L。通过Vonkossa染色观察MEPE对人牙髓细胞矿化的影响。结果:MEPE蛋白能促进人牙髓细胞的矿化。结论:MEPE具有促进人牙髓细胞的矿化的能力,可能在牙齿生长发育过程中起着重要的作用。     

Bone formation after sinus augmentation with engineered bone

Objectives: The aim of the following investigation was to quantify the resorption rate of tissue-engineered bone grafts in the maxillary sinus using volume measurements. MATERIAL AND METHODS: Sinus floor augmentation using autologous bone grafts from the iliac crest (n=17, group 1) was compared with commercially produced transplants of human cells seeded on polyglycolid-polylactid (PLGA) scaffolds (Oral Bone) (n=14, group 2). RESULTS: The total resorption rate for autologous transplants 3 months post operation was 29%, while the tissue-engineered bone showed a resorption rate of 90%. The autologous bone had a bone density of up to 266-551 Hounsfield units (HU), while sufficient mineralization of tissue-engineered bone was found in only one case (152 HU). CONCLUSION: In this clinical study, the use of autologous cancellous bone grafts in sinus augmentation was more reliable than scaffolds containing cultured osteoblasts. Further tissue-engineered bone transplants should be examined to draw general conclusions about the use of tissue-engineered grafts compared with autologous bone grafts for maxillary sinus augmentation.     

Dentin structure in familial hypophosphatemic rickets: benefits of vitamin D and phosphate treatment

OBJECTIVE: To evaluate the outcome of 1-(OH) vitamin D and oral phosphate treatment on dentin structure in patients with familial hypophosphatemic rickets, and expression of SIBLINGs (a family of non-collagenous proteins involved in dentinogenesis) and osteocalcin. PATIENTS AND METHODS: Seven patients with familial hypophosphatemic rickets (age 3-16 years) were studied before or during treatment. Deciduous and permanent teeth were prepared for scanning electron microscopy (SEM) analysis and immunohistochemistry. RESULTS: Untreated or inadequately treated patients had necrotic teeth with impaired dentin mineralization including unmerged calcospherites and accumulation of non-collagenous proteins in wide interglobular spaces. Most of the primary incisors analyzed displayed fissures linking enamel subsurface to pulp horn. These elements may explain the bacterial penetration and dental abscesses despite the absence of carious lesions. Well-treated patients had healthy teeth with good dentin mineralization and little evidence of calcospherites. CONCLUSION: Treatment of hypophosphatemic children with 1-(OH) vitamin D and oral phosphate insures good dentin development and mineralization, and prevents clinical anomalies such as the dental necrosis classically associated with the disease. Starting treatment during early childhood and good adherence to the therapy are mandatory to observe these beneficial effects.     

Effects of 3-dimensional Bioprinting Alginate/Gelatin Hydrogel Scaffold Extract on Proliferation and Differentiation of Human Dental Pulp Stem Cells

IntroductionAlginate/gelatin hydrogel (Alg-Gel) scaffold has been applied in tissue engineering, but the research on its application in dental tissues regeneration is still lacking. We investigated the effect of this scaffold on human dental pulp stem cells (hDPSCs).MethodshDPSCs were cultured in both Alg-Gel and 3D-printed Alg-Gel scaffolds. Cell growth and adhesion were compared using fluorescein isothiocyanate–phalloidin staining and scanning electron microscopic micrographs. Changes in the proliferation in hDPSCs cultured in the complete culture medium containing aqueous extracts of the Alg-Gel or 3D-printed Alg-Gel scaffolds were examined using Cell Counting Kit-8 assay and flow cytometry analysis. Cells were cultured in the mineralization medium containing aqueous extracts of the Alg-Gel or 3D-printed Alg-Gel scaffolds for 7 or 14 days, and the differentiation of cells was shown by alizarin red S staining and alkaline phosphatase staining. The messenger RNA and protein expression of mineralization-related genes were detected with real-time polymerase chain reaction and Western blotting. Elemental analysis was used to test the material extract composition.ResultsMore cells were grown and adhered to the 3D-printed Alg-Gel scaffolds than the Alg-Gel scaffolds. The aqueous extracts of 3D-printed scaffolds can promote cell proliferation, and compared with Alg-Gel scaffolds, the extracts of 3D-printed scaffolds were more effective. Compared with the negative control group, 3D-printed Alg-Gel scaffold and Alg-Gel scaffold aqueous extracts promoted osteogenic/odontoblastic differentiation of hDPSCs with the enhanced formation of bone-like nodules and the alkaline phosphatase staining. The expression of mineralization-related genes was also up-regulated. 3D-printed scaffold aqueous extract contained more calcium and phosphorus ions than the Alg-Gel scaffold.ConclusionsThese findings suggest that compared with the Alg-Gel scaffold, 3D-printed Alg-Gel is more suitable for the growth of hDPSCs, and the scaffold extracts can better promote cell proliferation and differentiation.     

Altered Bone Material Properties in HLA‐B27 Rats Include Reduced Mineral to Matrix Ratio and Altered Collagen Cross‐Links

Spondyloarthropathy and inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, are often associated with severe osteopenia/osteoporosis in both children and adults. HLA‐B27 transgenic rats present a phenotype that includes severe colitis and severely accelerated alveolar bone loss. The purpose of this study was to evaluate long bone density status, systemic bone metabolic markers, and intrinsic bone material properties in HLA‐B27 transgenic (TG) rats, and compare them with those of age‐ and sex‐matched wild‐type (WT) animals. The results indicate that in the HLA‐B27 rat, an animal susceptible to both alveolar bone loss (ABL) and long bone osteopenia, there is a statistically significant negative correlation between ABL and long bone bone mineral density (BMD), as well as mineral/matrix ratio at active bone‐forming trabecular surfaces. The TG animals had a lower mineral/matrix ratio and higher relative proteoglycan and advanced glycation end product (?‐N‐Carboxymethyl‐L‐lysine) content and pyridinoline/divalent collagen cross‐link ratio compared with WT. These results may provide better understanding of the interrelationship between osteoporosis and oral bone loss, the underlying causes of the inferior bone strength in the HLA‐B27 transgenic animals, and could prove to be a useful model in the elucidation of the pathophysiology of spondyloarthropathy and IBD‐associated osteopenia/osteoporosis and in the evaluation of pharmacological intervention(s) against such conditions. © 2014 American Society for Bone and Mineral Research.     

Costly teeth? Gestation length in primates suggests that neonate dentition is not expensive to produce

Variation in the relationship between gestation length and body mass can arise because different types of tissue require varying amounts of energy to build, and not all species build such tissues in the same proportions. Given that a pregnant female has a finite amount of energy, trade-offs between investment in different tissues may occur. Here we examine if dental precocity accounts for variation in primate gestation length. If true, this could explain why folivorous species with precocial dentition have longer gestation lengths than predicted by neonatal brain and body mass. We compiled data on gestation length, neonate and adult female body and brain mass from the literature. We used published postcanine eruption schedules at 4 months of age and measured the total occlusal area as dental endowment to approximate dental precocity at birth. Species with embryonic delay in growth or altricial neonates were not considered because they represent grade shifts regarding gestation length. Consequently, our data were biased toward Simiiformes and Old World monkeys, specifically. We performed a phylogenetic generalized least squares regression (pGLS) of neonate brain mass in relation to neonate body mass, and a second pGLS with dental endowment as an additional predictor variable. Including dental endowment in the pGLS did not improve the model. Dental endowment did not systematically impact primate gestation length. Concordant with results from previous studies, this indicates that the energetically expensive period of tooth mineralization may occur postnatally. More data are required to examine if the results are typical across primates.