腹壁修补材料的研究及应用进展

巨大腹壁缺损的修补是外科医生经常面临的难题,寻找理想的修补材料以修复缺损至关重要。用于修复腹壁缺损的材料一般分为生物性和非生物性两种。前者的力学性能较好,而后者的生物相容性更佳。目前公认尚没找到一种完全理想的腹壁替代材料.作者对常用生物材料和非生物材料的特性、应用、优缺点等做一综述。     

胶原蛋白作为医用生物材料的应用

胶原蛋白是一类具有活跃生物功能的细胞外间质成分,占人体总蛋白质总量的1/3。胶原蛋白是组织的支持物和填充物,也主动参与了细胞迁移、分化及增殖,并与创伤修复及胚胎发育有关。以胶原蛋白为原料制备的生物替代物(如人造皮肤等)必然大大优于非生物材料的同类产品。目前,大量不同性能及用途的胶原蛋白医用材料不断涌现,有些已结束实验室及动物实验阶段,大批量投入临床应用。     

肿瘤细胞三维培养支架、血管及细胞间的相互作用

背景：肿瘤组织工程通过构建综合的培养模型,充分模拟肿瘤在体内生长的微环境,可以较好地研究肿瘤发生发展的动力学及相关治疗策略。 目的：综述肿瘤工程技术中的肿瘤细胞三维培养。 方法：以“tumor engineering; 3D culture; biological materials; dynamic”为关键词,检索PubMed数据库1992年1月至2013年3月相关文献,纳入有关肿瘤工程、肿瘤细胞三维培养、生物支架材料及肿瘤微环境的相关文章。 结果与结论：三维培养因其可再现组织细胞的体内生长情况,已成为研究肿瘤耐药性、侵袭性和肿瘤微环境的重要平台,在许多领域表现出逐步取代平面培养技术的趋势,为肿瘤研究提供了一个非常接近于体内真实情况的研究平台。近年来,随着肿瘤工程学的发展,多种新型高分子聚合材料被应用于肿瘤细胞的三维立体培养,三维培养技术逐渐成为肿瘤生物学领域研究的热点,其利用各种方法及材料使细胞呈空间立体方式生长,形成类似体内生长环境的生物支撑或基质,建立细胞间及细胞与胞外基质间的相互联系,并形成特定的类似组织样的三维空间结构。生物材料就是种子细胞生长的土壤,在肿瘤工程中起着替代细胞外基质或组织、器官的基质的作用。而随着三维细胞培养技术在肿瘤研究中的广泛应用,其已成为肿瘤耐药、血管形成、细胞间相互作用、信号转导、干细胞等方面研究不可或缺的有力工具。     

骨诱导性磷酸钙陶瓷材料修复牙槽突裂

BACKGROUND: In our previous studies, we had prepared calcium phosphate ceramics with better ectopic osteogenesis. OBJECTIVE: To explore the effect of novel osteoinductive calcium phosphate ceramics in the repairing of alveolar cleft. METHODS: Bilaterl alveolar defects were created in nine immature beagles. Three months later, osteoinductive calcium phosphate ceramics with high modular surface (experimental group) and smooth surface (control group) were randomly implanted in each side of the defect. Meanwhile, the corresponding material was implanted into the thigh muscle. New bone formation in the implanted region, osteogenesis in the implanted region and muscle, and respair results were respectively observed by fluorescence microscope, light microscope and CT at 4, 8 and 12 weeks after implantation. RESULTS AND CONCLUSION: (1) Fluorescence microscope observation: A circular permutation of red, yellow and green fluorescent strip could be observed in both two groups. (2) Light microscope observation: At 12 weeks after implantation, in the experimental group, the bone reconstruction was obvious, the implant material was decomposed gradually, the gap was filled with a large number of mature bone that combined with the rest material closely, and numerous Haversian canals appeared; the control group was similar but slightly inferior to the experimental group in the quality of new bone. The experimental group material successfully induced heterotopic osteogenesis in muscle, while the control did not. (3) CT examination: The two group materials restored the appearance and continuity of the alveolar ridge, and made no effect on the eruption of permanent teeth in both sides of the defect. To conclude, our findings suggest that the novel osteoinductive calcium phosphate ceramic exhibits advantages in alveolar cleft repair with earlier osteogenesis activation, faster osteogenesis rate and more bone formation than those traditional materials.     

兔股骨髁临界性骨缺损动物模型制备及临界骨缺损值

文题释义：临界性骨缺损：首先定义为自然状况下骨缺损不进行任何处理无法自愈的最短的骨缺损尺寸。随后考虑到观察实验动物完整的生命周期是非常困难的,将临界性骨缺损值定义为在实验期间物种不能自行愈合的最短骨缺损尺寸。 动物模型：是在医学研究中建立的模拟人类疾病表现的动物,骨组织工程中建立临床相关的测试动物模型来研究材料的生物相容性、降解、力学性能以及与宿主组织的相互作用,是体外实验和人体临床试验之间的关键一步。 背景：兔股骨远端骨缺损模型被研究者们广泛用于骨缺损替代骨组织工程材料的测试,但对于兔股骨髁圆柱形骨缺损模型的大小文献报道不一,直径分布在5-9 mm,深度8-12 mm,目前尚无统一的标准。 目的：建立兔股骨髁不同尺寸骨缺损模型,确定兔股骨髁临界性骨缺损尺寸。 方法：6月龄雄性新西兰白兔18只,随机分为3组,每组各6只,分别建立骨缺损模型,骨缺损直径依次为5,6,7 mm,深度均为10 mm,双侧手术,共计12侧。分别于术后第1天及术后第4,8,12周行CT扫描及三维重建,CT-Hedberg评分评价骨缺损愈合情况;于术后12周处死新西兰白兔,取出股骨髁缺损样本,通过大体观察和苏木精-伊红染色分析缺损区愈合情况。实验方案经徐州医科大学实验动物道德伦理委员会批准。 结果与结论：①术后所有兔均存活,术后12周大体观察示：直径5 mm组缺损由新生骨组织充填,股骨髁塑形良好,骨缺损基本完全修复;直径6 mm组、直径7 mm组骨缺损区可见明显凹陷,新生骨组织较少,骨缺损未修复;②CT图像示：术后第4,8周,直径5 mm组缺损区逐渐减小,断端桥接;直径6 mm、直径7 mm组缺损区仅周边有少量新生骨长入,缺损面积较前稍减小;术后第12周可见直径5 mm组皮质骨结构完整、连续,骨缺损基本完全修复;直径6 mm组骨缺损部分修复;直径7 mm组缺损未修复,仍可见明显缺损空腔存在;③CT-Hedberg评分显示,术后各时间点直径6 mm组评分显著低于直径5 mm组(P < 0.05);与直径7 mm组比较差异无显著性意义(P > 0.05);④组织学结果示：术后12周直径5 mm组缺损区出现排列不规则的骨小梁结构,并可见大量新生骨组织填充,其他2组在骨缺损周边可见部分新生骨小梁存在,但缺损区新生骨组织填充较少;⑤结果说明,在12周的实验观察期内,在缺损深度同为10 mm的条件下,直径>6 mm的股骨髁缺损未能自行愈合,而直径<6 mm的股骨髁缺损基本完全修复。此结果符合临界骨缺损的标准,故直径6 mm可作为兔股骨髁临界骨缺损值。 ORCID: 0000-0002-1257-965X(徐石庄) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Osteoinductivity and biomechanics of a porous ceramic with autogenic periosteum

Twenty-one dogs were used to study the osteoinductivity and biomechanical properties of a biphasic porous ceramic with autogenic periosteum implanted in muscle. The ceramic implants were swathed in fresh periosteum derived from the same animals and implanted in the femur muscles. The other two groups of animals served as controls using the same material implanted in the femur bones and muscles without periosteum. Biomechanical measurements showed that, in the muscles, the experimental group had a higher bending strength than the unswathed group by the time the samples were harvested. Six months postoperatively, the strength of the samples in the experimental group had almost reached that of normal bones. The results of X-ray diffraction and infrared spectrometric analysis suggested that the degradation rate and speed of tricalcium phosphate (TCP) of the ceramic in the experimental group were faster than in the unswathed samples, but slower than in samples implanted in bones. The bone replacement and bone-inducing activity were excellent in the periosteum-swathed samples. Histologically, satisfactory bone repair was seen in the experimental samples. All results indicate that autogenic periosteum could increase bioactivity of ceramics in heterosites and improve bone formation in the surroundings of porous calcium phosphate ceramics. The data also infer that the complicated procedure of culturing bone growth factors with biomaterials in vitro to obtain bioactive grafts could be replaced by this relatively simple method.     

聚左旋乳酸/壳聚糖纳米纤维三维多孔支架复合骨髓间充质干细胞修复兔骨缺损**△

背景：骨髓间充质干细胞具有向多种间质细胞谱系分化的能力,且支架材料的性能对骨缺损的修复有重要影响。 目的：观察聚左旋乳酸/壳聚糖纳米纤维三维多孔支架复合骨髓间充质干细胞治疗骨缺损。 方法：对骨缺损模型兔分别采用空白植入、髂后上棘自体松质骨移植、聚左旋乳酸/壳聚糖纳米纤维多孔支架移植和复合了骨髓间充质干细胞的聚左旋乳酸/壳聚糖纳米纤维多孔支架移植修复缺损部位。 结果与结论：至移植12周,移植复合了骨髓间充质干细胞的聚左旋乳酸/壳聚糖纳米纤维多孔支架的实验兔的缺损处有骨组织生成,支架材料降解,已完成缺损修复,其修复情况接近松质骨组;髂后上棘自体松质骨移植的实验兔的缺损修复完好,新形成的骨组织较规则;只植入聚左旋乳酸/壳聚糖纳米纤维多孔支架的实验兔有少量骨组织形成,材料部分降解;空白植入的实验兔缺损处无新生骨组织生成,主要由纤维结缔组织填充。说明新型的生物支架材料聚左旋乳酸/壳聚糖纳米纤维三维多孔支架与来源于新西兰大白兔的骨髓间充质干细胞复合培养后,植入同种异体兔股骨髁缺损处,使骨缺损的修复速度加快,表现为较好的体内诱导成骨的作用。     

成骨诱导脂肪基质细胞在骨组织工程体内成骨中的作用

背景：以往研究认为,经过成骨诱导后的脂肪基质细胞通过转化为成骨细胞分泌骨基质进而修复骨缺损,然而并没有明确结论证实。 目的：将经过体外成骨诱导的脂肪基质细胞复合支架材料分别植入骨缺损区和非骨区,根据是否成骨,验证经过成骨诱导后的脂肪基质细胞是否转化为成骨细胞。 方法：取12月龄犬背部皮下脂肪,经胶原酶消化法获得单个核细胞,将培养的第3代细胞与双相磷酸钙陶瓷形成复合物。在犬下颌骨两侧制备长20 mm、高10 mm的箱状缺损,拔除术区牙齿,将细胞支架复合物植入一侧术区,空白侧留作对照;另外在犬背部皮下肌肉区植入细胞支架复合物及骨诱导性磷酸钙陶瓷材料,术后6周及12周经组织学检测骨缺损修复情况。 结果与结论：脂肪基质细胞复合双相磷酸钙陶瓷在骨缺损区成骨,在肌肉区未形成新骨;骨诱导性磷酸钙陶瓷在肌肉区形成新骨。提示成骨诱导并不能将脂肪基质细胞转化为成骨细胞,其确切机制有待进一步研究。     

Osteoinduction of hydroxyapatite/β-tricalcium phosphate bioceramics in mice with a fractured fibula

Many studies have shown that calcium phosphate ceramics can induce bone formation in non-osseous sites without the application of any osteoinductive biomolecules, but the mechanisms of this phenomenon (intrinsic osteoinduction of bioceramics) remain unclear. In this study, we compared the intrinsic osteoinduction of porous hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) implanted in mice at different sites. In 30 mice the left fibula was fractured and the right fibula was kept intact. A porous HA/β-TCP cylinder was implanted into both the left (group 1) and right (group 2) leg muscles of each animal. In addition, two HA/β-TCP cylinders were bilaterally implanted into leg subcutaneous pockets (group 3) in each of the remaining 15 mice. New bone formation was studied in the three groups by histology, histomorphometry and immunostaining. In group 1 new bone was observed at week 6 and bone marrow appeared at week 12. In group 2 new bone was observed at week 8 and bone marrow appeared at week 12. The new bone area percentage in group 1 was significantly higher than in group 2 at both weeks 8 and 12. In contrast, group 3 did not show any new bone within the period studied. These differences were explained based on the location of the implants and thus their proximity to the osteogenic environment of fracture healing. The results support the hypothesis that intrinsic osteoinduction by calcium phosphate ceramics is the result of adsorption of osteoinductive substances on the surface.     

多孔碳酸钙陶瓷与干细胞源性成骨细胞的相容性

背景：国内外的研究证实普通碳酸钙陶瓷作为骨替代材料时具有细胞支架作用。 目的：观察多孔碳酸钙陶瓷与成骨细胞的相容性,及作为骨组织工程支架的可能性。 方法：SD大鼠骨髓基质干细胞经矿化诱导培养、扩增并检测证实其已具成骨细胞表型后,分别与多孔碳酸钙陶瓷支架、普通羟基磷灰石陶瓷支架体外复合培养。 结果与结论：骨髓基质干细胞经体外诱导形成成骨细胞,钙结节、Ⅰ型胶原和碱性磷酸酶免疫染色结果阳性。多孔碳酸钙陶瓷支架材料与羟基磷灰石陶瓷材料皆有细胞附着生长,但多孔碳酸钙陶瓷支架材料细胞的黏附能力、增殖活力及成骨活性均强于羟基磷灰石陶瓷材料。提示多孔碳酸钙陶瓷支架材料与SD大鼠骨髓基质干细胞源性成骨细胞有良好相容性。     

多孔磷酸钙骨水泥与转染骨形态发生蛋白2基因的骨髓间充质干细胞复合修复股骨髁骨缺损

BACKGROUND: Bone morphogenetic protein (BMP) can improve the osteogenesis capacity of tissue-engineered bone. However, how to prolong BMP release is a key for constructing tissue-engineered bone. OBJECTIVE: To study the repair effect of porous calcium phosphate cement (CPC) with bone marrow mesenchymal stem cells transfected with BMP-2 gene on bone defects. METHODS: After modeling of bilateral femoral condyle bone defects, 12 model rabbits were given implantation of porous CPC with bone marrow mesenchymal stem cells transfected with BMP-2 on the left (experimental group) and given implantation of porous CPC with bone marrow mesenchymal stem cells on the right (control group). Bilateral femoral condyles were taken and analyzed histologically at 4 and 12 weeks after implantation. RESULTS AND CONCLUSION: Better osteogenesis including more newly formed bone tissues and faster scaffold absorption was observed in the experimental group compared with the control group at 4 and 12 weeks after implantation. The area of newly formed bone tissues at different time and rate of bone formation at 12 weeks were significantly higher in the experimental group than in the control group (P < 0.001, P < 0.05). These findings indicate that transfer of BMP-2 into bone marrow mesenchymal stem cells combined with porous CPC could increase repair of bone defects.     

Adsorption and release of insulin-like growth factor-I on porous tricalcium phosphate implant

In order to develop bone substitutes, the design of biomaterials like calcium phosphate ceramic loaded with bone growth factor are of great interest. However, it is necessary to control the amount of growth factor adsorbed onto ceramics and the kinetics of its release. Radiolabeling of insulin-like growth factor-I (IGF-I) with 125-iodine ([(125)I]-IGF-I) and its adsorption onto porous tricalcium phosphate (TCP) cylinders enabled us to establish the time-adsorption and time-release curves using various concentrations of IGF-I. The adsorption curve increased rapidly and then flattened out at 72 h; 90% of the maximum was already reached at 24 h; and 20% of the adsorbed IGF-I was released in water within 4 days. In human serum the release was faster at 82% within 4 days. In vivo evaluation on an animal model was then performed. Rabbits' bilateral femoral cylindrical bone defects were filled with the TCP cylinders, which were either carrying IGF-I or implanted alone as a control in each rabbit. Bone turnover and ceramic resorption were stimulated by IGF-I loaded TCP according to standard radiography, dual-energy X-ray absorptiometry, histology, and histomorphometry.     

Effects on articular cartilage of subchondral replacement with polymethylmethacrylate and calcium phosphate cement.

Bone defects were created in rabbit medial femoral condyle in a model where subchondral bone was completely removed or about 2 mm of subchondral bone was maintained. Groups without augmentation and augmented with autogenous bone, polymethylmethacrylate, or calcium phosphate cement were sacrificed at 3, 12, and 24 weeks for evaluation of articular cartilage and observation of bone formation. In the model in which subchondral bone was completely removed, collapse of the subchondral bone together with exfoliation and prolapse of cartilage developed early in all cases. In the model in which 2 mm of subchondral bone was maintained, degeneration of articular cartilage developed at 12 weeks in the group augmented with polymethylmethacrylate, showing a significant difference when compared to the contralateral untreated control group. The group augmented with calcium phosphate cement did not demonstrate any evident difference from the control group. Mechanical properties after subchondral replacement did not differ between the groups augmented with polymethylmethacrylate and calcium phosphate cement, although calcium phosphate cement was considered histologically superior. Calcium phosphate cement was a reliable subchondral replacement material when the bone defect is adjacent to the articular cartilage.