Cotransplantation of mesenchymal stromal cells and endothelial cells on calcium carbonate and hydroxylapatite scaffolds in vivo

This study investigated the cotransplantation of bone marrow mesenchymal stromal cells (BMSC) and human umbilical cord endothelial cells (HUVEC), and evaluated their contribution to vascular and bone tissue engineering in vivo.To evaluate the success of osteogenic differentiation and timely vascularization of different osteoconductive scaffolds in vivo, we transferred BMSC and HUVEC pre-cultivated calcium carbonate (CaCO₃) and hydroxylapatite (HA) matrices into immunocompromised RNU-rats, and analyzed mineralization, expression of osteopontin, and vascular integration via new vessel formation.After in vivo transplantation, pre-cultivated scaffolds demonstrated overall improved mineralization of 44% for CaCO₃ (p = 0.01, SD ± 14.3) and 34% for HA (p = 0.001, SD ± 17.8), as well as improved vascularization of 5.6 vessels/0.1 mm² on CaCO₃ (p < 0.0001, SD ± 2.0) and 5.3 vessels/0.1 mm² on HA (p < 0.0001, SD ± 2.4) compared with non-pre-cultivated controls. However, no significant differences between the implantation of BMSC-only, HUVEC-only, or BMSC + HUVEC cocultures could be observed.There is an increasing demand for improved bone regeneration in tissue engineering. Cotransplantation of mesenchymal stromal cells and endothelial cells often demonstrates synergistic improvements in vitro. However, the benefits or superiority of cotransplantation was not evident in vivo and so will require further investigation.     

人髁突骨髓间充质干细胞体内成骨的实验研究

目的 探讨人髁突来源骨髓间充质干细胞(bone marrow-derived mesenchymal stem cells,BMSC)体内分化成骨的能力,为构建组织工程髁突提供种子细胞.方法取切除的人髁突冲洗收集骨髓细胞,采用密度梯度离心和贴壁培养法进行培养和纯化BMSC,取第3或4代BMSC进行成骨细胞和成软骨细胞诱导分化后接种于珊瑚骨支架表面,扫描电镜观察细胞在支架表面的黏附和增殖状况.将成骨或成软骨细胞-珊瑚骨支架植入裸鼠背部皮下,6和9周后观察体内成骨和成软骨情况.结果 培养3～7d后扫描电镜显示细胞黏附于珊瑚骨支架表面,呈多层生长,并跨越微孔连成网状或片状;植入裸鼠体内9周,髁突形珊瑚骨支架均基本维持最初的形态,可见散在或片状的新生骨形成,新生软骨呈岛状分布.结论从人髁突骨髓中分离出的BMSC具有体内形成新骨和软骨组织的能力,可作为构建组织工程髁突的种子细胞.     

骨髓间质干细胞人工骨构建的实验研究

目的 本实验分析体外构建细胞性组织工程化人工骨的可能性。方法 采用兔骨髓间质干细胞，经体外扩增培养并诱导分化为具有成骨能力的种子细胞，再与生物可降解材料ε-己内酯与环氧乙烷共聚物复合培养，在体外构建人工骨。通过电镜观察和组织学切片观察来评价可降解材料与种子细胞的复合培养的效果。结果 骨髓间质干细胞可在体外扩增培养；骨髓间质干细胞在条件培养液的诱导下，可以定向分化为具有成骨能力的细胞类型。诱导分化后的骨髓间质干细胞可在生物可降解材料ε-己内酯与环氧乙烷共聚物上黏附和铺展。结论 骨髓间质干细胞可在体外传代扩增培养，并可在一定条件下向成骨类型细胞转化，可作为骨组织工程种子细胞。己内酯与环氧乙烷的共聚物与种子细胞相容性好，可作为组织工程用的细胞支架材料。在体外，生物可降解材料ε-己内酯与环氧乙烷共聚物与种子细胞复合培养后可以构建出具有活细胞成分的组织工程骨。     

Reconstruction of bone using calcium phosphate bone cements: a critical review.

The calcium phosphate cements (CPCs) are rapidly emerging as a new technology in craniofacial surgery and will soon impact many areas of orthopedic and maxillofacial reconstructive surgery as well. These materials are, in many ways, substantially different from the previously marketed dense, crystalline, hydroxyapatite (HA) ceramic materials of the 1980s. The CPCs are blends of amorphous and crystalline calcium phosphate compounds and set to produce HA. These materials 1) have x-ray diffraction spectra similar to the mineral phase of bone, 2) set endothermically at body temperature, 3) are capable of being injected into fractures or bone defects, 4) have compressive strengths equal to or greater than bone, 5) form chemical bonds to the host bone, and 6) may exhibit osteoconductive properties. This review provides an overall commentary on the different types of CPCs, emphasizing those materials currently on the market or soon to emerge in the marketplace.     

兔骨髓间质干细胞诱导分化的生物特性研究

目的：本研究的目的在于研究骨髓间质干细胞体外诱导、分化培养的特性，以期寻找BMSC体外培养扩增和诱导分化的适宜时机和方法。方法：采用兔来源的骨髓间质干细胞体外扩增培养；选用不同代数的BMSC进行诱导分化，并行生物学检测。结果：兔骨髓间质干细胞可在体外培养扩增，形态类似成纤维样细胞；骨髓间质干细胞在条件培养液的存在下，可以分化成有成骨能力的细胞类型；体外可合成分泌类骨质钙盐。BMSC随代数的增加其生物反应性逐渐降低，并呈一定规律性。结论：骨髓间质干细胞可在体外传代扩增培养，在一定条件下可向成骨类型细胞转化，并随传代次数的增加，其转化效率与生物学性质成规律性变化。一定传代数的BMSC适于作为骨组织工程的种子细胞。     

兔骨髓基质干细胞骨向诱导实验研究

目的:研究兔骨髓基质干细胞(bone marrow stromal cells,BMSC)的体外培养以及骨向诱导分化情况,进一步探讨其作为骨组织工程种子细胞的可行性。方法:无菌条件下抽取兔的股骨骨髓,然后进行骨髓基质干细胞的分离和体外培养,并向成骨细胞定向诱导分化。结果:体外分离的骨髓基质细胞呈贴壁生长,改良MTT法测定显示骨髓基质细胞于第7.8天左右可达到增殖高峰;诱导后BMSC可向成骨细胞分化,细胞呈成骨细胞形态为梭形和多角形并可形成钙化结节。改良钙钴染色法检测诱导细胞碱性磷酸活性呈强阳性。扫描电镜观察细胞呈较典型的成骨细胞状态,并可见钙盐沉积。结论:骨髓基质细胞具有来源充足,取材方便,创伤小无明显并发症。骨髓基质干细胞分化增殖能力较强,成骨能力确定。所以采用骨髓基质细胞作为种子细胞构建组织工程骨有比较可靠的依据。     

The use of adult stem cells in rebuilding the human face

BACKGROUND: Stem cells have been isolated from a variety of embryonic and postnatal (adult) tissues, including bone marrow. Bone marrow stromal cells (BMSCs), which are non-blood-forming cells in marrow, contain a subset of skeletal stem cells (SSCs) that are able to regenerate all types of skeletal tissue: bone, cartilage, blood-supportive stromal cells and marrow fat cells. METHODS: Bone marrow suspensions are placed into culture for analysis of their biological character and for expansion of their number. The resulting populations of cells are used in a variety of assays to establish the existence of an adult SSC, and the ability of BMSC populations to regenerate hard tissues in the craniofacial region, in conjunction with appropriate scaffolds. RESULTS: Single-cell analysis established the existence of a true adult SSC in bone marrow. Populations of ex vivo expanded BMSCs (a subset of which are SSCs) are able to regenerate a bone/marrow organ. In conjunction with appropriate scaffolds, these cells can be used to regenerate bone in a variety of applications. CONCLUSIONS: BMSCs have the potential to re-create tissues of the craniofacial region to restore normal structure and function in reconstructing the hard tissues of a face. Ex vivo expanded BMSCs with scaffolds have been used in a limited number of patients to date, but likely will be used more extensively in the near future.     

3D打印多孔磷酸镁生物陶瓷支架的制备及其体外骨诱导能力的研究

目的:应用3D打印技术及致孔剂浸出法制备具有两种不同尺度孔隙的磷酸镁多孔支架,研究其物理化学性能及骨诱导能力。方法:通过间接打印法制备多孔磷酸镁(MgP)支架,利用Na Cl(粒径25~50μm)作为致孔剂引入微孔,制备MgPNa微孔支架;通过扫描电镜、压汞仪、通用材料试验机及X线衍射仪检测支架的物理及化学性能;应用CCK8和DAPI染色检测人骨髓间充质干细胞(h BMSC)在支架上的增殖和黏附;采用茜素红染色和碱性磷酸酶(ALP)定量实验评估支架促h BMSC成骨分化的能力。结果:MgP-Na支架具有更高的孔隙率(P<0.05),同时微孔的存在明显降低了MgP-Na支架的压缩强度(P<0.05)。两组支架均具有良好的生物相容性,h BMSC可在支架上黏附与增殖,并且微孔结构更有利于细胞的黏附(P<0.05)。MgP-Na支架对于h BMSC的钙沉积和成骨分化具有更加积极的作用(P<0.05)。结论:磷酸镁多孔支架有望成为修复骨缺损的新型骨组织工程支架,MgP-Na支架的微孔结构在体外骨诱导中起到了积极有效的作用。     

颌面部骨结构部位特异性重建的组织工程技术:第1部分

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Tissue engineering osteochondral implants for temporomandibular joint repair

Tissue engineering has provided an alternative to traditional strategies to repair and regenerate temporomandibular joints (TMJ). A successful strategy to engineer osteochondral tissue, such as that found in the TMJ, will produce tissue that is both biologically and mechanically functional. Image-based design (IBD) and solid free-form (SFF) fabrication can be used to generate scaffolds that are load bearing and match patient and defect site geometry. The objective of this study was to demonstrate how scaffold design, materials, and biological factors can be used in an integrated approach to regenerate a multi-tissue interface. IBD and SFF were first used to create biomimetic scaffolds with appropriate bulk geometry and microarchitecture. Biphasic composite scaffolds were then manufactured with the same techniques and used to simultaneously generate bone and cartilage in discrete regions and provide for the development of a stable interface between cartilage and subchondral bone. Poly-l-lactic acid/hydroxyapatite composite scaffolds were differentially seeded with fibroblasts transduced with an adenovirus expressing bone morphogenetic protein-7 in the ceramic phase and fully differentiated chondrocytes in the polymeric phase, and were subcutaneously implanted into mice. Following implantation in the ectopic site, the biphasic scaffolds promoted the simultaneous growth of bone, cartilage, and a mineralized interface tissue. Within the ceramic phase, the pockets of tissue generated included blood vessels, marrow stroma, and adipose tissue. This combination of IBD and SFF-fabricated biphasic scaffolds with gene and cell therapy is a promising approach to regenerate osteochondral defects and, ultimately, the TMJ.     

新型多孔HA/PDLLA支架体外细胞相容性的实验研究

目的:研究新型多孔羟基磷灰石/聚乳酸(HA/PDLLA)支架材料的体外细胞相容性。方法:贴壁法培养兔骨髓基质细胞(bone marrow stromal cells,BMSCs),经体外矿化诱导培养、扩增后,与实验组 A(含2%HA 的 HA/PDLLA)、实验组 B(含4%HA 的 HA/PDLLA)及对照组(PDLLA)分别进行体外复合培养;并通过定性及定量检测细胞在材料表面的粘附能力、增殖活力,验证细胞材料复合体的成骨活性,比较分析各组支架材料之间的差异。结果:兔 BMSCs在三组支架材料的表面均能生长,经体外诱导后在支架材料的表面形成钙结节,实验组 A 与 B 细胞的粘附及增殖能力均强于对照组(P<0.05)。结论:兔 BMSCs 与新型多孔 HA/PDLLA 支架材料有良好的细胞相容性。     

基因修饰的组织工程化骨修复骨质疏松症骨缺损的实验研究

目的 探讨人类骨形成蛋白2（hBMP-2）基因修饰的组织工程化骨修复骨质疏松症者骨缺损的可行性及方法。方法24只6个月龄雌性SD大鼠建立去势模型，按体重编号，随机分组。3个月后实验组骨髓问质干细胞（BMSC）转染hBMP-2质粒，对照组未作干预，在体外构建自体细胞组织工程化骨，植入下颌骨缺损区。结果术后4周时实验组有新生骨质形成，8周时成熟骨基质形成；对照组新生骨质数量明显少于实验组，且材料边缘及中央处有脂肪样结构形成。结论hBMP-2基因修饰的组织工程化骨可用于骨质疏松症者骨缺损的治疗。     

Construction of tissue-engineered bone with differentiated osteoblasts from adipose-derived stem cell and coral scaffolds at an ectopic site

Cell sheets from bone marrow mesenchymal stem cells (BMSC) have been widely used in the field of bone tissue engineering, although their source remains a challenging issue. In this study, adipose-derived stem cells (ADSC) were induced to differentiate into osteoblasts, and the incorporation of coral scaffolds with ADSC sheets for bone formation at an ectopic site was also investigated. First, ADSC isolated from inguinal adipose tissue of New Zealand rabbits were cultured for two weeks without passaging under osteogenic induction, and the microstructures of cell sheets were analysed by histological and scanning electron microscope (EM) observation. In addition, the activity of alkaline phosphatase (ALP) and alizarin red staining was also measured to detect their osteogenic ability. Subsequently, ADSC were proved to be able to proliferate well when seeded on the coral scaffolds. Next, coral scaffolds were wrapped in cell sheets to prepare sheet-coral complexes, which were implanted into subcutaneous pockets in nude mice. At eight weeks after implantation, gross examination, microcomputed tomography (MicroCT), and histological analysis were investigated to assess new bone formation. MicroCT scanning and histological analysis showed that there was more highly dense tissue formed in the complex group than control group (p=0.0004). These results indicated that osteoblastic ADSC sheets could be used to construct engineered bone and the incorporation of coral scaffolds with ADSC sheets significantly improved bone formation, providing a newly approach for bone tissue engineering.     

Effect of vitamin D pretreatment of human mesenchymal stem cells on ectopic bone formation

Adult mesenchymal stem cells (MSCs) are used in contemporary strategies for tissue engineering. The MSC is able to form bone following implantation as undifferentiated cells adherent to hydroxyapatite (HA)/tricalcium phosphate (TCP) scaffolds. Previous investigators have demonstrated that human MSCs (hMSCs) can be differentiated to osteoblasts in vitro by the inclusion of vitamin D and ascorbic acid. The aim of this study was to compare the osteogenic potential of predifferentiated and undifferentiated bone marrow-derived, culture-expanded hMSCs adherent to synthetic HA/TCP (60%/40%) following subcutaneous engraftment in severe combined immunodeficiency (SCID) mice. During the final 3 days of culture, cells were grown in Dulbecco's modified Eagle's medium containing 10% fetal calf serum and antibiotics or media containing 25-mM calcium supplementation with vitamin D and ascorbic acid. Four weeks following implantation in SCID mice, scoring analysis of bone formation within the cubes revealed the absence of bone formation in unloaded cubes. Bone formation compared by a qualitative bone index was 7.23% for undifferentiated cells compared to 5.20% for differentiated cells. Minimal resorption was observed at this early time point. In this ectopic model, predifferentiation using a combination of vitamin D and ascorbic acid failed to increase subsequent bone formation by implanted cells. Following implantation of hMSCs adherent to an osteoconductive scaffold, host factors may contribute dominant osteoinductive signals or impose inhibitory signals to control the fate of the implanted cell. Predifferentiation strategies require confirmation in vivo.     

Bone formation in trabecular bone cell seeded scaffolds used for reconstruction of the rat mandible

This study tested whether different in vitro cultivation techniques for tissue-engineered scaffolds seeded with human trabecular bone cells affect in vivo bone formation when implanted into critical-size defects in rat mandibles. Human trabecular cells were isolated and seeded into three types of scaffolds (porous CaCO₃, mineralized collagen, porous tricalcium phosphate). Four in vitro groups were produced: empty control scaffolds incubated with cell culture medium for 24 h; scaffolds seeded with trabecular bone cells, cultivated under static conditions for 24 h; scaffolds seeded with trabecular bone cells, cultivated for 14 days under static conditions; scaffolds seeded with trabecular bone cells, cultivated for 14 days in a continuous flow perfusion bioreactor. The scaffolds were implanted press fit into non-healing defects, 5 mm diameter, in rat mandibles. After 6 weeks the presence of human cells was assessed; none were detected. Histomorphometric evaluation showed that neither seeding human trabecular bone cells nor the culturing technique increased the amount of early bone formation compared with the level provided by osteoconductive bone ingrowth from the defect edges. It is concluded that human bone marrow stroma cells in tissue-engineered scaffolds and associated in vitro technology are difficult to test in the mandible in animal models.     

重组人骨保护素抑制破骨细胞及促进羟磷灰石修复去势大鼠下颌骨缺损的研究

目的 探讨转染人骨保护素（hOPG）基因的大鼠骨髓间充质干细胞（rBMSCs）复合羟磷灰石（HA）支架对去势大鼠下颌骨缺损的修复作用。方法 将重组腺病毒pDC316-hOPG-EGFP转染rBMSCs,蛋白质印迹法和骨磨片试验分别检测hOPG的表达水平和抑制破骨细胞功能;构建骨质疏松大鼠模型,分别将HA支架、未转染rBMSCs复合HA支架、转染rBMSCs复合HA支架植入大鼠下颌骨骨缺损,6周后通过抗酒石酸酸性磷酸酶、苏木精-伊红染色检测骨缺损区破骨细胞及骨修复情况。结果 体外携载有hOPG基因的腺病毒成功转染rBMSCs,转染后的rBMSCs表达具有抑制破骨细胞活性功能的hOPG;表达hOPG的rBMSCs复合HA支架后骨缺损处破骨细胞明显减少,成骨增多。结论 转染hOPG基因的rBMSCs在体内外均具有抑制破骨细胞功能的作用,且转染rBMSCs复合HA支架可促进骨质疏松大鼠的下颌骨缺损修复。     

牙槽骨缺损修复后牙齿移动的动物实验

目的探讨用组织工程方法修复大鼠下颌骨缺损对牙齿移动的影响。方法选用40只SD大鼠，获取大鼠骨髓基质细胞，分离培养并诱导为成骨样细胞。将成骨样细胞与陶瓷化骨复合，种植到大鼠下颌骨的一侧全层骨缺损区。缺损修复8周后，在手术组和正常对照组大鼠下颌安装正畸矫治器，加力近中移动第一磨牙。观察牙齿移动距离和牙根长度的变化，t检验比较组间差异。结果加力初期，手术组大鼠的牙齿移动距离大于对照组，差异有统计学意义（P〈0．05）。手术组牙根长度变化小于对照组，差异有统计学意义（P〈0．05）。结论应用陶瓷化骨复合体外诱导的大鼠自体成骨样细胞，可修复大鼠的下颌骨缺损，修复手术不会对牙齿移动产生不良影响。     

Engineered cartilage with internal porous high-density polyethylene support from bone marrow stromal cells: A preliminary study in nude mice

Tissue-engineered cartilage may have potential for the construction of clinical implants for the treatment of congenital deformities or post-traumatic defects. However, the lack of seed cells is a challenge, as is the maintenance of ideal shape and size. We have used bone marrow stromal cells (BMSCs) and a pre-shaped polyglycolic acid (PGA)-porous high-density polyethylene composite scaffold to solve these problems. High-density polyethylene was carved into cylindrical rods and encircled with PGA fibres to form scaffolds. Porcine BMSC were seeded into the scaffold and cultured in chondrogenic medium (high-glucose Dulbecco's modified Eagle's medium with 10% (v/v) fetal bovine serum, dexamethasone 40 ng/ml, transforming growth factor-β1 10 ng/ml, and insulin-like growth factor 50 ng/ml) for 3 weeks in vitro before the cell-scaffold constructs were implanted subcutaneously into nude mice. After 8 weeks of implantation, all specimens in the experimental group had formed mature cartilage around the polyethylene, and the prefabricated shapes and sizes were well maintained. The neoformed cartilage also grew into the pores of the scaffold with a fine interface between them; this gave the whole regenerated composite tissue characteristics similar to those of native cartilage. These results show that it is feasible to construct cartilage using BMSC and PGA-high-density polypropylene scaffolds. This may remove some of the obstacles that have prevented the clinical use of cartilage engineering such as limited volume, deformation, and a limited number of seed cells.     

磷酸钙钠/β-磷酸三钙陶瓷支架接种骨髓基质细胞成骨性能的研究

目的：观察磷酸钙钠／β-磷酸三钙(NaCaPO2/β-TCP)支架接种骨髓基质细胞后植入裸鼠皮下的成骨性能。方法：通过理化方法,将煅烧牛松质骨转化为NaCaPO2/β-TCP双相钙磷陶瓷。获取兔髂骨松质骨骨髓基质细胞,体外分离、扩增、诱导后,接种于NaCaPO2/β-TCP支架。将支架／细胞复合物植入裸鼠背部皮下,NaCaPO2/β-TCP陶瓷单纯植入作为对照。植入后4、8周取材,通过大体、组织学观察,评价成骨活性。结果：支架／细胞复合物植入后4周,材料表面见相对较成熟的骨组织,内部主要为软骨;植入后8周,大量骨小梁形成。可见骨髓腔、骨髓细胞及脂肪细胞,在支架材料和骨组织的邻接区域见成骨细胞及破骨细胞。可见软骨内成骨方式。结论：NaCaPO2/β-TCP支架接种骨髓基质细胞后显示良好的成骨活性,能够促进未成熟骨矿化,可以作为骨组织工程支架材料。     

生物陶瓷材料应用于颌面部骨缺损修复与再生的研究进展

生物陶瓷材料是一类具有良好生物相容性、较强的抗压缩性、耐腐蚀性及抗微生物活性等优点的陶瓷材料或金属氧化物。骨组织工程技术是一种应用骨源性细胞、骨传导支架、生长因子修复受损骨组织的技术手段,为颌面部骨组织缺损治疗提供了新的策略。文章就近年来生物陶瓷材料在颌面部骨缺损修复与再生中的应用研究进展做一综述。