成骨细胞的生物学特征及其调控活性物质

骨质疏松症是以骨质量的丢失以及骨组织的退变为特征的骨代谢疾病,成骨细胞在骨重建过程中具有重要 作用。论述了成骨细胞的生物学特征,以及在成骨细胞增殖、分化、功能表达、凋亡等过程中起调控作用的生物活性物 质。     

牛骨胶原蛋白肽促进人成骨细胞增殖

目的研究牛骨胶原蛋白肽对人成骨细胞增殖的影响。方法分离培养人成骨细胞,茜素红矿化染色鉴定人成骨细胞的成骨特性,利用MTT实验检测胶原蛋白肽对人成骨细胞的增殖效应。结果茜素红矿化染色结果表明,HBC具有成骨能力,胶原蛋白肽对HBC的增殖具有促进作用,0.3mg/ml胶原蛋白肽对细胞的增殖具有最佳效应。结论牛骨胶原蛋白肽促进人成骨细胞增殖,为骨质疏松的预防和治疗提供理论依据。     

黄芪总黄酮对大鼠原代成骨细胞的影响及其机制研究

在大鼠颅骨原代成骨细胞中加入不同浓度的黄芪总黄酮(ATF),用MTT法检测细胞增殖,用碱性磷酸酶(ALP)活性、Ⅰ型胶原及骨钙素水平检测细胞分化,用茜素红染色法检测细胞矿化,用ELISA法和Western blot方法检测成骨细胞中骨形成蛋白(BMP-2)及核心结合因子(Runx-2)的表达。结果表明,ATF能剂量依赖性地促进大鼠原代成骨细胞的增殖、分化及矿化,同时上调成骨细胞中BMP-2和Runx-2蛋白的表达。提示ATF可能通过上调成骨细胞中BMP-2和Runx-2的表达来促进成骨细胞的成骨活性。     

淫羊藿苷调控BMP-2与OSX促进成骨细胞增殖的研究

目的:探讨淫羊藿苷(ICA)调控BMP-2与OSX对成骨细胞MC3T3-E1增殖的影响。方法:不同浓度淫羊藿苷处理成骨细胞后,细胞增殖实验(CCK-8)和碱性磷酸酶(ALP)检测评价成骨增殖分化能力,激光共聚焦显微镜观察成骨细胞的骨架形态,免疫印迹法(WesternBlot)检测骨形态发生蛋白-2(BMP-2)和成骨相关转录因子(OSX)表达。结果:与对照组相比,淫羊藿苷促进成骨细胞增殖分化,4μg/L淫羊藿苷对成骨细胞增殖作用最佳。细胞活性升高,镜下可见细胞伸展更多伪足,Western Blot显示BMP-2和OSX表达增高(p0.05)。结论:淫羊藿苷有促进成骨细胞增殖分化,可能是通过调节BMP-2和OSX蛋白表达。     

聚醚醚酮表面接枝聚丙烯酸及其成骨细胞相容性

采用紫外光诱导接枝聚合技术制备表面接枝聚丙烯酸(PAA)的聚醚醚酮(PEEK)以改善其成骨细胞相容性。用X射线光电子能谱、衰减全反射红外光谱和水接触角测试对表面改性的PEEK进行表征,同时,用MC3T3-E1成骨细胞评价PEEK表面接枝PAA后的成骨细胞相容性和成骨分化活性。结果表明,采用紫外光诱导接枝聚合技术在PEEK表面成功接枝PAA;与未处理的PEEK表面相比,接枝PAA的PEEK表面能显著改善成骨细胞的黏附、铺展与增殖,但对成骨细胞的成骨分化活性并没有明显的促进作用。     

微囊化共培养诱导骨髓间充质干细胞体外定向成骨分化研究

为了模拟体内成骨微环境,为骨组织工程提供一种调控干细胞体外向成骨细胞定向分化的共培养新方法,SD大鼠骨髓间充质干细胞和包埋在海藻酸钠-聚赖氨酸-海藻酸钠(alginate-poly-lysine-alginate,APA)微胶囊中的SD大鼠成骨细胞进行体外共培养。共培养过程中,通过碱性磷酸酶(ALP)定量、定性分析以及钙化结节(von Kossa)染色等手段来评价骨髓间充质干细胞向成骨细胞定向分化。结果表明在体外微囊化共培养过程中,被诱导细胞的胞内ALP酶活性逐渐高于对照组的干细胞,接近于成骨细胞;ALP以及von Kossa定性染色证实被诱导细胞具有较高的ALP活性以及具有分泌钙基质的能力。微囊化成骨细胞和外部干细胞的共培养体系较好地模拟了体内干细胞向成骨细胞转化的成骨微环境,促进了干细胞向成骨细胞的体外定向分化;微胶囊膜将成骨细胞和干细胞进行了隔离,避免了两者的直接接触和可能的细胞交叉污染混合,同时利于分离目的细胞,这种微囊化共培养体系为骨组织工程提供了一种安全调控干细胞体外成骨定向分化的工程化新方法。     

类骨磷灰石的体外制备及体外细胞学评价

目的探讨体外合成类骨磷灰石,并对其进行体外细胞生物学性能评价。方法通过明胶诱导和无机离子共杂化的作用,利用化学沉淀法体外合成类骨磷灰石,利用MC3T3-El小鼠胚胎骨细胞对其浸提液进行细胞学评价。MTT法检测骨细胞增殖;类骨磷灰石浸提液培养基中用β-甘油磷酸钠为骨诱导剂诱导MC3T3-El定向分化为成骨细胞,碱性磷酸酶(ALP)染色法测定骨细胞分化的能力。结论体外合成的类骨磷灰石具有与自然骨无机相相似的化学组成和晶体结构。类骨磷灰石浸提液在实验早期,能够显著促进MC3T3-El小鼠胚胎骨细胞增殖,并且可以诱导分化为成骨细胞。     

悬浮和贴壁成骨细胞渗透压耐受极限及膜渗透性质的研究

在优化组织工程骨低温保存程序时,需要了解体外培养的种子细胞成骨细胞的渗透特性.尤其对于高浓度的玻璃化保护剂,更有必要设计合适的保护剂导入、洗脱方案来减小高浓度保护剂的渗透效应损伤及其化学毒性作用.利用显微镜图像分析法研究了用于构建组织工程骨的种子细胞—-成骨细胞的渗透特性,其中包括细胞的等渗体积、细胞在高渗及低渗溶液中...     

骨碎补对成骨细胞和破骨细胞作用的研究进展

对2005年以来相关文献进行综述。综述了骨碎补对成骨细胞和破骨细胞作用的研究进展,为骨碎补的进一步研究提供新思路。骨碎补能够促进成骨细胞的增殖分化,抑制破骨细胞,其机理与调节多种骨相关蛋白及其mRNA表达有关。应加强骨碎补有效成分及体内作用机制的研究。     

雌激素受体信号通路与骨质疏松症相关性的研究进展

骨质疏松症是一种由于骨量减少和骨组织结构疏松导致骨脆性增加,且易发生骨折的全身性疾病。该病主要与闭经、生活方式、营养、各种激素代谢异常及遗传等因素有关。女性体内有多个部位含雌激素受体(estrogen receptor,ER),ER包括ERα和ERβ两种亚型,可与雌激素结合形成复合物二聚体,激活多种下游信号级联反应,对成骨细胞的骨形成过程和破骨细胞的骨吸收过程发挥重要调节作用,从而影响成骨分化能力。本文主要对ER信号通路与骨质疏松症相关性作一综述。     

生物质基含硅骨修复复合支架材料的制备、特性及评价

模仿天然骨的精密结构制备有机-无机复合骨修复支架材料已成为骨组织工程发展的重要方向。生物质材料如胶原、明胶、壳聚糖、丝素蛋白等由于具有优良的生物学性能而得到广泛关注。含硅生物活性材料由于具有良好的骨传导性和骨诱导性,成为骨修复支架材料中重要的无机组分。本文主要介绍了粉体复合和原位复合两种骨支架材料组分的复合技术,阐述了冷冻干燥、静电纺丝、仿生矿化以及3D打印等骨支架材料结构的构建策略,着重总结了生物质基含硅骨修复支架材料研究进展,阐明当前骨支架材料制备的难点在于支架材料的力学性能和多孔性结构以及生物降解性能与新骨生成速率之间的匹配性问题,并对骨支架材料的发展进行了展望。     

Locally Secreted Semaphorin 4D Is Engaged in Both Pathogenic Bone Resorption and Retarded Bone Regeneration in a Ligature-Induced Mouse Model of Periodontitis

It is well known that Semaphorin 4D (Sema4D) inhibits IGF-1-mediated osteogenesis by binding with PlexinB1 expressed on osteoblasts. However, its elevated level in the gingival crevice fluid of periodontitis patients and the broader scope of its activities in the context of potential upregulation of osteoclast-mediated periodontal bone-resorption suggest the need for further investigation of this multifaceted molecule. In short, the pathophysiological role of Sema4D in periodontitis requires further study. Accordingly, attachment of the ligature to the maxillary molar of mice for 7 days induced alveolar bone-resorption accompanied by locally elevated, soluble Sema4D (sSema4D), TNF-α and RANKL. Removal of the ligature induced spontaneous bone regeneration during the following 14 days, which was significantly promoted by anti-Sema4D-mAb administration. Anti-Sema4D-mAb was also suppressed in vitro osteoclastogenesis and pit formation by RANKL-stimulated BMMCs. While anti-Sema4D-mAb downmodulated the bone-resorption induced in mouse periodontitis, it neither affected local production of TNF-α and RANKL nor systemic skeletal bone remodeling. RANKL-induced osteoclastogenesis and resorptive activity were also suppressed by blocking of CD72, but not Plexin B2, suggesting that sSema4D released by osteoclasts promotes osteoclastogenesis via ligation to CD72 receptor. Overall, our data indicated that ssSema4D released by osteoclasts may play a dual function by decreasing bone formation, while upregulating bone-resorption.     

Controlling surface microstructure of calcium phosphate ceramic from random to custom-design

Calcium phosphate ceramics have long been studied as bone graft substitutes due to their similarity with the mineral constitute of bone and teeth, excellent biocompatibility and bioactivity. Chemical composition, macrostructure and surface microstructure are believed to be important for the bone formation within calcium phosphate ceramics. Surface microstructure has shown its crucial role in the osteogenic response of calcium phosphate ceramics; however the presence of surface irregularities and random distribution of surface microstructure in traditional calcium phosphate ceramics make it difficult to explain how surface microstructure play its role in bone formation. In the present study, we evaluated the influence of various starting apatites and sintering temperatures on the surface microstructure of the resulting hydroxyapatite ceramics. In order to minimize the randomness of the surface microstructure, laser ablation was used to generate custom-designed surface microstructures. The resulting hydroxyapatite ceramics with controlled surface microstructures would be helpful to study the role of surface microstructure on bone formation and may provide useful information for further optimization of calcium phosphate ceramics for bone regeneration.     

3D Environment Is Required In Vitro to Demonstrate Altered Bone Metabolism Characteristic for Type 2 Diabetics

A large British study, with almost 3000 patients, identified diabetes as main risk factor for delayed and nonunion fracture healing, the treatment of which causes large costs for the health system. In the past years, much progress has been made to treat common complications in diabetics. However, there is still a lack of advanced strategies to treat diabetic bone diseases. To develop such therapeutic strategies, mechanisms leading to massive bone alterations in diabetics have to be well understood. We herein describe an in vitro model displaying bone metabolism frequently observed in diabetics. The model is based on osteoblastic SaOS-2 cells, which in direct coculture, stimulate THP-1 cells to form osteoclasts. While in conventional 2D cocultures formation of mineralized matrix is decreased under pre-/diabetic conditions, formation of mineralized matrix is increased in 3D cocultures. Furthermore, we demonstrate a matrix stability of the 3D carrier that is decreased under pre-/diabetic conditions, resembling the in vivo situation in type 2 diabetics. In summary, our results show that a 3D environment is required in this in vitro model to mimic alterations in bone metabolism characteristic for pre-/diabetes. The ability to measure both osteoblast and osteoclast function, and their effect on mineralization and stability of the 3D carrier offers the possibility to use this model also for other purposes, e.g., drug screenings.     

Bone Regeneration of a 3D-Printed Alloplastic and Particulate Xenogenic Graft with rhBMP-2

This study aimed to evaluate the bone regeneration capacity of a customized alloplastic material and xenograft with recombinant human bone morphogenetic protein-2 (rhBMP-2). We prepared hydroxyapatite (HA)/tricalcium phosphate (TCP) pure ceramic bone blocks made using a 3D printing system and added rhBMP-2 to both materials. In eight beagle dogs, a total of 32 defects were created on the lower jaws. The defective sites of the negative control group were left untreated (N group; 8 defects), and those in the positive control group were filled with particle-type Bio-Oss (P group; 12 defects). The defect sites in the experimental group were filled with 3D-printed synthetic bone blocks (3D group; 12 defects). Radiographic and histological evaluations were performed after healing periods of 6 and 12 weeks and showed no significant difference in new bone formation and total bone between the P and 3D groups. The 3D-printed custom HA/TCP graft with rhBMP-2 showed bone regeneration effects similar to that of particulate Bio-Oss with rhBMP-2. Through further study and development, the application of 3D-printed customized alloplastic grafts will be extended to various fields of bone regeneration.     

New Function of Cholesterol Oxidation Products Involved in Osteoporosis Pathogenesis

Osteoporosis (OP) is a systemic bone disease characterized by decreased bone strength, microarchitectural changes in bone tissues, and increased risk of fracture. Its occurrence is closely related to various factors such as aging, genetic factors, living habits, and nutritional deficiencies as well as the disturbance of bone homeostasis. The dysregulation of bone metabolism is regarded as one of the key influencing factors causing OP. Cholesterol oxidation products (COPs) are important compounds in the maintenance of bone metabolic homeostasis by participating in several important biological processes such as the differentiation of mesenchymal stem cells, bone formation in osteoblasts, and bone resorption in osteoclasts. The effects of specific COPs on mesenchymal stem cells are mainly manifested by promoting osteoblast genesis and inhibiting adipocyte genesis. This review aims to elucidate the biological roles of COPs in OP development, starting from the molecular mechanisms of OP, pointing out opportunities and challenges in current research, and providing new ideas and perspectives for further studies of OP pathogenesis.     

Positive and Negative Regulators of Sclerostin Expression

Sclerostin is secreted from osteocytes, binds to the Wnt co-receptor Lrp5/6, and affects the interaction between Wnt ligands and Lrp5/6, which inhibits Wnt/β-catenin signals and suppresses bone formation. Sclerostin plays an important role in the preservation of bone mass by functioning as a negative regulator of bone formation. A sclerostin deficiency causes sclerosteosis, which is characterized by an excess bone mass with enhanced bone formation in humans and mice. The expression of sclerostin is positively and negatively regulated by many factors, which also govern bone metabolism. Positive and negative regulators of sclerostin expression and their effects are introduced and discussed herein based on recent and previous findings, including our research.     

Vitamin D: Link between Osteoporosis,Obesity, and Diabetes?

Vitamin D (1,25(OH)₂D₃) is a steroid hormone that has a range of physiological functions in skeletal and nonskeletal tissues, and can contribute to prevent and/or treat osteoporosis, obesity, and Type 2 diabetes mellitus (T2DM). In bone metabolism, vitamin D increases the plasma levels of calcium and phosphorus, regulates osteoblast and osteoclast the activity, and combats PTH hypersecretion, promoting bone formation and preventing/treating osteoporosis. This evidence is supported by most clinical studies, especially those that have included calcium and assessed the effects of vitamin D doses (≥800 IU/day) on bone mineral density. However, annual megadoses should be avoided as they impair bone health. Recent findings suggest that low serum vitamin D is the consequence (not the cause) of obesity and the results from randomized double-blind clinical trials are still scarce and inconclusive to establish the relationship between vitamin D, obesity, and T2DM. Nevertheless, there is evidence that vitamin D inhibits fat accumulation, increases insulin synthesis and preserves pancreatic islet cells, decreases insulin resistance and reduces hunger, favoring obesity and T2DM control. To date, there is not enough scientific evidence to support the use of vitamin D as a pathway to prevent and/or treat obesity and T2DM.     

3D Printed SiOC(N) Ceramic Scaffolds for Bone Tissue Regeneration: Improved Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells

Bone tissue engineering has developed significantly in recent years as there has been increasing demand for bone substitutes due to trauma, cancer, arthritis, and infections. The scaffolds for bone regeneration need to be mechanically stable and have a 3D architecture with interconnected pores. With the advances in additive manufacturing technology, these requirements can be fulfilled by 3D printing scaffolds with controlled geometry and porosity using a low-cost multistep process. The scaffolds, however, must also be bioactive to promote the environment for the cells to regenerate into bone tissue. To determine if a low-cost 3D printing method for bespoke SiOC(N) porous structures can regenerate bone, these structures were tested for osteointegration potential by using human mesenchymal stem cells (hMSCs). This includes checking the general biocompatibilities under the osteogenic differentiation environment (cell proliferation and metabolism). Moreover, cell morphology was observed by confocal microscopy, and gene expressions on typical osteogenic markers at different stages for bone formation were determined by real-time PCR. The results of the study showed the pore size of the scaffolds had a significant impact on differentiation. A certain range of pore size could stimulate osteogenic differentiation, thus promoting bone regrowth and regeneration.