骨髓间充质干细胞复合表面改性的3-羟基丁酸和3-羟基己酸共聚酯膜的体外相容性

目的: 研究大鼠骨髓间充质干细胞(BMSCs)在不同处理工艺的3-羟基丁酸和3-羟基己酸共聚酯(PHBHHx)膜材料上的生长、增殖情况,为组织工程学筛选出一种新型的适合细胞生长、增殖的生物材料.方法: 用全骨髓培养法获得BMSCs,并行免疫荧光鉴定,同时在成骨诱导液中诱导BMSCs,钙钴法检测碱性磷酸酶(ALP),茜素红矿化结节染色;成脂诱导后行油红O染色.将不同处理工艺的材料与第3代BMSCs复合培养1、 3、 7d,通过扫描电镜、MTT法和中性红染色法分别观察细胞的形态、增殖变化及分布情况.结果: BMSCs免疫荧光鉴定CD44、 CD106均呈阳性.经成骨诱导后,ALP呈阳性表达,矿化结节染色呈橘红色;经成脂诱导后,14d油红O染色呈阳性.细胞在经过碱处理或添加5%、 10%中药涂层的PHBHHx膜材料表面均生长状态良好,增殖活力强且分布均匀.结论: 经过碱处理的,且含5%、 10%中药涂层的PHBHHx膜,具有良好的BMSCs相容性,可以作为一种新型的生物材料应用于组织工程.     

羊膜基质/聚丙烯复合补片的制备及其生物相容性评价

制备脱细胞羊膜基质, 运用物理方法将其复合于临床用聚丙烯补片, 以形成具有更好组织相容性的生物补片。通过细胞培养, 以聚丙烯膜为对照, 评价复合生物补片的细胞相容性;通过动物皮下植入实验, 以评价复合补片的组织相容性。结果表明, 复合补片羊膜基质表面上的成纤维细胞生长和形态均好于聚丙烯表面, 细胞增殖较快, 增殖率超过聚丙烯表面的50%。动物实验显示, 复合补片周围增生少, 无明显纤维包膜形成, 初期在植入周围有淋巴细胞等炎性细胞浸润, 随着羊膜逐渐降解, 4周时可见毛细血管新生;而对于聚丙烯材料, 植入处纤维包囊明显, 炎性情况也较严重。经羊膜基质复合的聚丙烯补片具有良好的细胞和组织相容性。     

砷涂层支架置入后的血管组织相容性

背景：研究认为,三氧化二砷可以抑制血管平滑肌细胞的增殖,促进其凋亡,那么砷对血管平滑肌细胞的增生是否也有同样的抑制作用,砷涂层血管支架能否与血管组织相容,早期较好地被血管内膜覆盖或达到减少内膜过度增生的作用？ 目的：观察砷涂层血管支架的血管组织相容性。 方法：取大耳白家兔14只,随机分为2组,分别在腹主动脉处植入砷涂层316 L不锈钢支架和316 L不锈钢裸支架,植入28 d后结扎支架部位血管的远端和近端,取下支架部位的血管行苏木精-伊红染色,光镜检查。 结果与结论：①大体观察：支架处的血管外径稍大于相邻处血管的外径,呈扩张状态,无肉眼可见的血栓,切开支架,支架表面可见光滑的新生内膜形成,新生内膜表面光滑。②光镜观察：支架丝位于血管的中层,中层平滑肌被压,支架丝周边,血管内膜平滑肌增生,使血管内膜增厚。支架丝的血管腔面可见新生的血管内膜形成并覆盖支架丝,支架丝与血管组织之间可见一薄层黑色物质,为涂层药物砷及其化合物,证明砷涂层支架可以被血管组织覆盖,具有良好的血管组织相容性。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;组织工程全文链接：     

脱细胞血管基质制备及体内外生物相容性

背景:利用脱细胞血管基质作为血管支架具有以下优点:脱细胞血管基质保留了自然血管的复杂三维结构;脱细胞基质表面的生长因子和结构域有利于细胞的黏附和浸润。目的:制备脱细胞血管基质并对其体内外生物相容性进行评价。方法:采用胰蛋白酶、Triton X-100逐步处理猪颈动脉制备脱细胞血管基质。采用皮下植入实验、急性毒性实验和体外细胞毒性实验等评价其生物相容性。结果与结论:脱细胞基质材料具有良好的化学稳定性,未释放对红细胞产生破坏溶解作用的有害元素,未引起急性溶血反应,对细胞的生长无毒性影响。脱细胞基质材料在动物体内植入后早期有较多炎性细胞浸润,到实验观察的后期无明显炎性细胞浸润,脱细胞基质内可见成纤维细胞。另外,脱细胞基质材料对周边组织未产生毒性作用,伤口Ⅰ期愈合。同时组织学切片显示:支架材料与周边组织相容性好,未产生排斥反应。说明脱细胞基质材料在动物体内具有很好的生物相容性。     

转染血管内皮细胞生长因子骨髓间充质干细胞与牛松质骨支架复合组织工程骨的血管形成

背景：小块组织工程骨植入动物体内后,早期依靠组织液的渗透可获得营养,但大块组织工程骨的营养仅靠组织液的渗透是远远不够的,必须通过血管再生来获得。 目的：观察转染血管内皮细胞生长因子表达载体骨髓间充质干细胞复合组织工程骨植入动物体内后的血管形成能力。 方法：制作日本大耳白兔双侧尺骨中段骨缺损模型,左侧尺骨缺损植入转染血管内皮细胞生长因子表达载体的自体骨髓间充质干细胞复合脱钙脱脂去蛋白的牛松质骨支架组织工程骨为实验组,右侧尺骨缺损植入自体骨髓间充质干细胞复合脱钙脱脂去蛋白的牛松质骨支架组织工程骨为对照组。术后12周行X射线摄片观察、大体标本观察、苏木精-伊红染色和Masson染色组织切片观察、MiFas图像分析系统定量分析。 结果与结论：实验组与对照组尺骨缺损处均有连续骨痂形成;组织切片经苏木精-伊红染色、Masson三色法染色及MiFas图像分析系统定量分析可见实验组和对照组均有大量的新生骨,但实验组新生血管明显多于对照组(P < 0.01),且血管较粗大,而且与新生骨接近。说明将转染血管内皮细胞生长因子表达载体的骨髓间充质干细胞复合在组织工程骨上植入动物体内可明显促进新生血管的形成。     

3D打印淫羊藿苷/脱钙骨基质修复兔股骨髁骨缺损

文题释义：脱钙骨基质：主要由93%胶原、5%可溶性蛋白及2%残余矿化基质组成的商业化生物材料，包含不同浓度的骨形态发生蛋白、生长因子及转化生长因子，具备良好的骨传导与骨诱导能力，可以单独或联合其他材料广泛用于骨折、骨不连、骨肿瘤、骨融合、股骨头坏死等治疗中。结构模型指数：是描述骨小梁组成结构中板层结构和杆状结构比例的参数。如果结构中骨小梁主要为板层结构，那么结构模型指数接近于0；如果结构中骨小梁主要为杆状结构，那么结构模型指数接近于3，该值越小骨小梁越成熟。背景：淫羊藿苷可促进骨髓间充质干细胞的增殖与成骨分化，具有良好的促成骨性能。脱钙骨基质具备良好的骨传导与骨诱导能力，可以单独或联合其他材料广泛用于骨修复中。 目的：观察3D打印淫羊藿苷/脱钙骨基质材料的缓释性能、细胞相容性与体内成骨性能。方法：利用3D打印技术制备淫羊藿苷/脱钙骨基质材料与脱钙骨基质材料，检测淫羊藿苷/脱钙骨基质材料的体外缓释性能。将骨髓间充质干细胞分别接种于两种材料表面，以单独培养的细胞为对照，于设定的时间点进行活/死染色、MTT、碱性磷酸酶活性与骨钙素含量检测。取新西兰大白兔30只，建立股骨髁骨缺损模型后分3组处理：对照组不植入任何材料，一组植入脱钙骨基质与同种异体兔骨髓间充质干细胞复合物，另一组植入淫羊藿苷/脱钙骨基质材料与同种异体兔骨髓间充质干细胞复合物，术后4，12周进行Micro-CT、组织学与力学性能检测。结果与结论：①3D打印淫羊藿苷/脱钙骨基质材料具有缓释性能，在28 d时淫羊藿苷释放量达总量的(54.9±7.9)%；②活/死染色显示，接种1 d后两组材料表面的细胞数量较少，随着培养时间的延长，细胞数量明显增多，至7 d时细胞形态良好，并且淫羊藿苷/脱钙骨基质材料表面的细胞更加均匀、数量更多；③MTT检测显示，淫羊藿苷/脱钙骨基质组培养7，10，14 d的细胞增殖快于其余两组(P < 0.05)；④淫羊藿苷/脱钙骨基质组培养7，10，14 d的碱性磷酸酶活性与骨钙素含量均高于其余两组(P < 0.05)；⑤术后12周Micro-CT显示，植入材料两组均可见大量的骨小梁，其中淫羊藿苷/脱钙骨基质组骨小梁数量更多、骨小梁厚度增加、骨小梁分离度更小；⑥术后12周组织学显示，植入材料两组可见大量骨组织形成，其中淫羊藿苷/脱钙骨基质组新生骨量最多；⑦淫羊藿苷/脱钙骨基质组抗压强度高于其余两组(P < 0.05)；⑧结果表明，3D打印淫羊藿苷/脱钙骨基质具有良好的缓释性能、细胞相容性与骨诱导性能。ORCID: 0000-0002-5272-812X(张虎雄) 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     

羟基丁酸-羟基辛酸一体化骨软骨支架的体外血管化

背景：前期实验构建的羟基丁酸-羟基辛酸共聚体一体化骨软骨支架具备良好的生物相容性、生物可降解性,并且降解产物无毒性。 目的：将兔肾微血管内皮细胞与羟基丁酸-羟基辛酸一体化骨软骨支架复合培养,观察支架骨层血管化效果。 方法：运用溶剂浇铸-颗粒沥滤法,制备具有骨层/骨与软骨界面层/软骨层3层结构的羟基丁酸-羟基辛酸一体化骨软骨支架。将传代培养至第3 代的兔肾微血管内皮细胞,接种到一体化骨软骨支架骨层支架上,MTT法检测细胞在支架上的增殖活性,10 d后苏木精-伊红染色及电镜观察细胞在支架内的生长状况。 结果与结论：一体化骨软骨支架外观具备明显的3层结构,各层之间连接紧密,骨层疏松多孔,各层支架孔隙均匀且相通,一体化支架孔隙率为78%。兔肾微血管内皮细胞在支架上分裂增殖良好,复合培养10 d后,细胞在骨层支架内呈立体生长,中间界面层内未发现细胞,苏木精-伊红染色可见细胞黏附生长于骨层支架孔隙间,细胞依附支架的多孔结构生长,形成管腔样结构,但细胞并未长入中间界面层。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;组织工程全文链接：     

内皮祖细胞在膀胱细胞外基质上的生长及分化

背景：传统的组织工程膀胱支架材料本身无血管结构,植入体内后面临血管化不足的问题。 目的：观察内皮祖细胞与膀胱细胞外基质的生物相容性。 方法：分离培养兔内皮祖细胞,种植于兔膀胱细胞外基质上与其复合培养。将复合生长材料植入兔背部皮下检测其组织相容性。 结果与结论：兔内皮祖细胞能够在膀胱细胞外基质表面正常黏附、生长、增殖,细胞形态良好。内皮祖细胞-膀胱细胞外基质植入兔体内后1周时,可见材料周围炎症反应明显,粘连严重,出血较多;苏木精-伊红染色可见组织中较多炎性细胞浸润,胶原及弹性纤维排列松散。植入后8周时可见材料已降解成碎细丝状,与周围组织融合生长在一起,但质地略脆,易出血;苏木精-伊红染色可见组织中已无明显炎症细胞浸润反应,胶原及弹性纤维排列紧密并且有新生血管长入其中。结果表明内皮祖细胞与膀胱细胞外基质具有良好的相容性,复合培养物与体内组织具有良好的相容性。     

骨髓间充质干细胞-聚乙醇酸支架复合体种植动物皮下构建组织工程化小口径血管

背景：课题组的前期工作已证实骨髓间充质干细胞可以诱导分化为血管内皮细胞和血管平滑肌细胞,并证实所诱导的细胞和胶原包埋的聚乙醇酸支架具有良好的组织相容性。 目的：探讨利用动物皮下作为生物反应器构建小口径组织工程化血管的可行性。 方法：骨髓间充质干细胞诱导分化为血管平滑肌样细胞和血管内皮样细胞,分层种植于胶原包埋聚乙醇酸支架表面,然后将细胞-支架复合体种植于动物皮下,构建小口径组织工程化血管。 结果与结论：人工血管组织学观察见管壁结构清晰,其大体结构和天然血管相似,可承受26.6 kPa的血管腔内压力不破裂。皮下培养8周免疫荧光观察Brdu标记的部分细胞核呈现明亮的黄绿色荧光。结果说明利用动物的皮下作为生物反应器,采用静态培养的方式构建小口径组织工程化血管是可行的。     

组织工程化血管移植实验研究

目的 通过体外构建、体内培养的方法 构建组织工程化血管,并将其植入动物的股动脉,探讨利用小口径组织工程化血管进行血管移植的可能性.方法 首先用Brdu标记所有种子细胞,将血管平滑肌样细胞和血管内皮样细胞分层种植于胶原包埋PGA的复合支架表面;然后将细胞和支架的复合体种植于动物皮下构建组织工程化血管,并移植到股动脉;最后行HE染色及免疫荧光等相关检查,了解移植后血管的特点及细胞来源.同时以移植物为单纯支架在皮下培养所形成的管状结构作为对照组.结果 移植后组织工程化血管通畅无血栓形成.HE染色见血管壁和正常生理性血管壁的结构相似.可分内膜、中膜和外膜三层.种植2周后Brdu标记细胞的免疫荧光观察证实血管壁细胞来源于所种植的种子细胞.结论 利用骨髓间充质干细胞分化而来的种子细胞和胶原包埋的PGA支架可以构建组织工程化小口径血管,而且可以移植入动物体内.     

Histopathologic changes of acellularized xenogenic carotid vascular grafts implanted in a pig-to-goat model

INTRODUCTION: The present study was designed to determine the in vivo patency and recellularization pattern of acellularized small-diameter xenogenic arterial grafts. We implanted acellularized porcine carotid arteries in bilateral carotid arteries of goats and microscopically analyzed the recellularization pattern of these grafts with the recipient's cells over time. MATERIAL AND METHODS: Carotid arteries of pigs weighing 30-40 kg were harvested and decellularized with hypertonic saline followed by sodium dodecyl sulfate. Acellularized porcine carotid vascular xenografts (0.4-0.5 cm in diameter) were prepared into 4 cm-long segments and implanted bilaterally in the carotid arteries of 10 black-haired goats. The in vivo patency of the implanted acellularized xenogenic grafts was evaluated at regular intervals by color Doppler ultrasonography. The goats were sacrificed at predetermined intervals (1 week, 1 month, 3 months, 6 months, 12 months after implantation), two animals at each interval. Upon retrieval, visual inspections and histopathologic examinations of the grafts were performed. To identify smooth muscle cells and functioning endothelial cells, immunohistochemical staining for alpha-smooth muscle actin and von Willebrand factor were also performed. RESULTS AND CONCLUSIONS: All experimental animals survived the observation period. Nineteen out of 20 implanted grafts showed patency with no thrombi. Microscopic analysis revealed that the grafts were completely covered with the hosts' endothelial cells, beginning from anastomotic sites. The grafts were gradually recellularized with recipients'cells including fibroblasts, myofibroblasts and smooth muscle cells. In conclusion, this study suggested that acellularized xenogenic vascular grafts can be a good alternative for the small-diameter vascular graft.     

人脐静脉内皮细胞与表面改性的PHBHHx膜的体外相容性

目的 评价人脐静脉内皮细胞（HUVECs）在含有不同组分中药涂层、碱处理前后的3-羟基丁酸和3-羟基已酸共聚酯（PHBHHx）膜上的生长状况,为研究PHBHHx膜与内皮细胞的生物相容性提供实验依据。 方法 用Baudine改良法分离培养人脐静脉内皮细胞,并用免疫组织化学方法鉴定;将已传至第3代人脐静脉内皮细胞接种于材料表面,培养8、12、24h,用扫描电镜观察人脐静脉内皮细胞在不同表面上黏附形态的变化,同时用细胞免疫荧光标记法比较其在不同膜上的分布情况,最后用四甲基偶氮唑盐(MTT)法检测各组细胞的活力。 结果 成功分离出人脐静脉内皮细胞,Ⅷ 因子及血管内皮细胞受体Ⅱ(FLK-1)染色阳性;人脐静脉内皮细胞培养结果表明,细胞在各组材料表面均呈良好生长,并大量增殖。MTT分析结果显示,碱处理的PHBHHx膜及添加5%、10%中药涂层的材料对人脐静脉内皮细胞的体外生长、增殖有促进作用;扫描电镜和荧光显微镜下可见,碱处理的PHBHHx膜及添加5%、10%中药涂层的材料表面的人脐静脉内皮细胞活力旺盛、形态饱满、分布均匀。 结论 经表面改性处理的、且加入5%、10%中药涂层的PHBHHx膜,具有良好的人脐静脉内皮细胞相容性,在体外细胞培养的环境下,有利于细胞的生长、贴附和增殖。     

An in vivo study of a gold nanocomposite biomaterial for vascular repair

Currently vascular repairs are treated using synthetic or biologic patches, however these patches have an array of complications, including calcification, rupture, re-stenosis, and intimal hyperplasia. An active patch material composed of decellularized tissue conjugated to gold nanoparticles (AuNPs) was developed and the long term biocompatibility and cellular integration was investigated. Porcine abdominal aortic tissue was decellularized and conjugated with 100 nm gold nanoparticles (AuNP). These patches were placed over a longitudinal arteriotomy of the thoracic aorta in six pigs. The animals were monitored for six months. Gross, histological, and immunohistochemical analyses of the patches were performed after euthanasia. Grossly there was minimal scar tissue with the patches still visible on the outer surface of the vessel. The inner lumen was smooth with a seamless transition from patch to native tissue. Histology demonstrated infiltration of host cells into the patch material. The immunohistochemical results demonstrated an endothelial cell layer forming over the patch within the vessel. Smooth muscle cells were repopulating the biomaterial in all animals. These results demonstrated that the AuNP biomaterial patch integrated well with the host tissue and did not failed over the six month implantation time.     

细胞培养法评价镁合金能化型共聚酯涂层的生物相容性

背景：与聚乳酸、聚羟基乙酸和乳酸-羟基乙酸共聚物等生物材料相比,3-羟基丁酸和3-羟基己酸共聚酯结构多元化,具有更好的生物相容性能、生物可降解性和热加工性能。 目的：采用细胞培养法评估含不同质量浓度阿魏酸的3-羟基丁酸和3-羟基己酸共聚酯涂层的生物相容性。 方法：室温下使用乙酸乙酯配制含0(对照组),50,100,130,150 g/L阿魏酸的3-羟基丁酸和3-羟基己酸共聚酯,观察成膜外观。通过MTT吸光度检测、荧光显微镜观察以及扫描电镜观察方法对比评估骨髓间充质干细胞在其表面的生长状态。 结果与结论：含50 g/L阿魏酸的3-羟基丁酸和3-羟基己酸共聚酯成膜后外观均匀半透明,未见白色结晶析出物,含100,130,150 g/L阿魏酸的3-羟基丁酸和3-羟基己酸共聚酯在成膜后均出现点状白色结晶物。MTT吸光度检测表明含50,100 g/L阿魏酸的3-羟基丁酸和3-羟基己酸共聚酯均能较好地促进骨髓间充质干细胞生长;荧光显微镜及扫描电镜观察均见骨髓间充质干细胞能够在含50,100 g/L阿魏酸的3-羟基丁酸和3-羟基己酸共聚酯表面黏附生长。说明含50 g/L阿魏酸的3-羟基丁酸和3-羟基己酸共聚酯最适合作为镁合金的涂层材料。     

Vascular patches tissue-engineered with autologous bone marrow-derived cells and decellularized tissue matrices

Synthetic polymer vascular patches used in cardiovascular surgery have shortcomings such as thrombosis, intimal hyperplasia, calcification, infection, and no growth potential. Tissue-engineered vascular patches using autologous vascular cells may solve these problems. In this study, we developed a tissue-engineered vascular patch using autologous bone marrow-derived cells (BMCs) and decellularized tissue matrices. Vascular smooth muscle cells and endothelial cells were differentiated from bone marrow mononuclear cells in vitro. Tissue-engineered vascular patches were fabricated by seeding these cells onto decellularized canine inferior vena cava matrices and implanted into the inferior vena cava of dogs. Three weeks after implantation, the tissue-engineered vascular patches were patent with no sign of thrombus formation. Histological, immunohistochemical, and electron microscopic analyses of the vascular patches retrieved 3 weeks after implantation revealed regeneration of endothelium and smooth muscle and the presence of collagen and elastin. BMCs labeled with a fluorescent dye prior to implantation were detected in the retrieved vascular patches, indicating that the BMCs survived after implantation and contributed to the vascular tissue regeneration. This study demonstrates that vascular patches can be tissue-engineered with autologous BMCs and decellularized tissue matrices.     

Effect of composition of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) on growth of fibroblast and osteoblast

Films made of poly (3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) (PHBHHx) consisting of 5%, 12% and 20% hydroxyhexanoate (HHx), respectively, were evaluated for biomedical application in comparison with poly (L-Lactide) (PLA). With the increase of HHx content in PHBHHx, the polymer surface properties changed accordingly. P(HB-co-20%-HHx) had the smoothest surface while PHB surface was most hydrophilic among the evaluated PHB and all the PHBHHx. All PHBHHx also showed strong protein affinity and biocompatibility. It was found that fibroblast and osteoblast had different responses to these polymers: fibroblast cells favored P(HB-co-20%-HHx), yet osteoblast cells preferred P(HB-co-12%-HHx). PHB and all PHBHHx appeared to have better biocompatibility for fibroblast and osteoblast compared with PLA. Polymers possessing different surface properties may help meet different cellular requirements. Combined with their good mechanical properties for elongation and adjustable biocompatibility, PHBHHx may meet the needs of growth requirements of different tissues and cells.     

小口径组织工程血管在羊体内的远期结果

背景：对小口径组织工程血管的研究至今仍主要集中于体外构建上,体内远期结果的研究少有报道。 目的：观察脱细胞猪股动脉支架和绵羊骨髓间质干细胞体外构建的小口径组织工程血管间置于骨髓间质干细胞供体绵羊体内12个月后组织学改变。 方法：将12只成年绵羊随机分为支架组和再细胞化组,支架组将猪股动脉脱细胞后间置于绵羊右侧股动脉;再细胞化组将体外诱导培养的绵羊骨髓间质干细胞种植于脱细胞猪股动脉支架中,经过体外预适应所构建的小口径组织工程血管(直径< 6 mm)间置于骨髓间质干细胞供体绵羊左侧股动脉;将12只绵羊的自体股动脉设为对照组。12个月后切取支架组和再细胞化组的植入物及邻近受体股动脉,行苏木精-伊红染色和扫描电镜检查,观察植入物和对照组股动脉内皮细胞及中层平滑肌细胞密度,采用邻甲酚酞络合酮法测定2组植入小口径组织工程血管和受体股动脉组织的钙含量。 结果与结论：支架组和再细胞化组植入后12个月内管腔均通畅,无明显管道扩张与狭窄,无腔内血栓形成,无管壁明显增厚等改变,管道内表面均已内皮化。但2组植入物管壁均有僵硬和搏动性减弱,尤以支架组植入物管壁僵硬更明显;支架组植入物管道组织钙含量最高(P < 0.01);支架组和再细胞化组管道中层平滑肌细胞密度均低于对照组(P < 0.01)。与支架组植入物相比,再细胞化组植入物组织钙含量较低(P < 0.05),中层平滑肌细胞密度较高(P < 0.01)。说明利用脱细胞猪股动脉支架体外构建小口径组织工程血管时,提高中层平滑肌细胞密度有助于改善小口径组织工程血管的远期功能。     

Explant pathology study of decellularized carotid artery vascular grafts

The purpose of this study was to evaluate the morphologic findings in small-diameter freeze-dried decellularized carotid artery grafts implanted in goats as carotid artery interposition grafts for 6-7 months. Unimplanted decellularized carotid artery grafts did not contain intact cells; however, remnants of smooth muscle cells were present in the media. The extracellular matrix was well preserved. All decellularized grafts were patent at explant, without significant dimensional changes or aneurysm formation. Their luminal surfaces were lined by a thin neointima, consisting of myofibroblasts, collagen, and a discontinuous layer of endothelial cells. Histologic evidence of calcification within the explants was not observed; however, electron microscopy showed calcification of minute remnants of cell membranes. Inflammatory cells were not present in the graft wall. Host cell migration was greatest in the adventitia along the length of the graft. Migration of host cells into the media was more apparent close to the anastomoses, forming cellular nests rich in extracellular proteoglycans, whereas cell migration into areas subjacent to the lumen was minimal. Ingrowth of host blood vessels was not observed. These results demonstrate satisfactory structural and morphologic features of a decellularized carotid artery small-diameter graft implanted for up to 7 months.     

Physical Properties and Biocompatibility of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Blended with Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) was blended with poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) to improve physical properties and biocompatibility of PHBHHx for a wide range of biomedical applications. PHBHHx was completely miscible with P3HB4HB in their blends. All the PHBHHx/P3HB4HB blends showed improved physical properties compared with PHBHHx, including higher thermal stability, flexibility and mechanical strength. All the blends had more hydrophilic surface, higher polar component and rougher surface than PHBHHx. The PHBHHx/P3HB4HB blend in 4:2 weight ratio showed the roughest surface and also had the highest chondrocyte viability among all the blends and the polymers tested, which was 59% higher than that on PHBHHx and 32% higher than that on P3HB4HB. The blend with 4:2 weight ratio also had the maximum cartilage-specific collagen II mRNA expression among all the blends and the polymers tested, which was 9-times higher than that on PHBHHx and 8-times higher than that on P3HB4HB. These results demonstrated that PHBHHx had improved physical properties and biocompatibility after blending with P3HB4HB. The blends could be used for cartilage tissue engineering.