Five-year clinical outcomes using the bioresorbable vascular scaffold: Insights from the FRANCE ABSORB registry

Central illustration: cumulative major adverse cardiac events (MACE) and bioresorbable vascular scaffold (BVS) thrombosis rates after 1, 2, 3, 4 and 5 years.

     

Evaluation of protection induced by a dengue virus serotype 2 envelope domain III protein scaffold/DNA vaccine in non-human primates

We describe the preclinical development of a dengue virus vaccine targeting the dengue virus serotype 2 (DENV2) envelope domain III (EDIII). This study provides proof-of-principle that a dengue EDIII protein scaffold/DNA vaccine can protect against dengue challenge. The dengue vaccine (EDIII-E2) is composed of both a protein particle and a DNA expression plasmid delivered simultaneously via intramuscular injection (protein) and gene gun (DNA) into rhesus macaques. The protein component can contain a maximum of 60 copies of EDIII presented on a multimeric scaffold of Geobacillus stearothermophilus E2 proteins. The DNA component is composed of the EDIII portion of the envelope gene cloned into an expression plasmid. The EDIII-E2 vaccine elicited robust antibody responses to DENV2, with neutralizing antibody responses detectable following the first boost and reaching titers of greater than 1:100,000 following the second and final boost. Vaccinated and naïve groups of macaques were challenged with DENV2. All vaccinated macaques were protected from detectable viremia by infectious assay, while naïve animals had detectable viremia for 2–7 days post-challenge. All naïve macaques had detectable viral RNA from day 2–10 post-challenge. In the EDIII-E2 group, three macaques were negative for viral RNA and three were found to have detectable viral RNA post challenge. Viremia onset was delayed and the duration was shortened relative to naïve controls. The presence of viral RNA post-challenge corresponded to a 10–30-fold boost in neutralization titers 28 days post challenge, whereas no boost was observed in the fully protected animals. Based on these results, we determine that pre-challenge 50% neutralization titers of >1:6000 correlated with sterilizing protection against DENV2 challenge in EDIII-E2 vaccinated macaques. Identification of the critical correlate of protection for the EDIII-E2 platform in the robust non-human primate model lays the groundwork for further development of a tetravalent EDIII-E2 dengue vaccine.     

人血浆作为真皮支架对自体皮肤增殖的影响：组织学和免疫组织化学试验●☆

背景：组织工程是一个多学科研究的交叉学科，其目标是使人体损伤的组织和器官再生，通过这种假设，几乎所有的动物组织都可以在实验室进行培养。一般的方法是从需要移植的患者身上提取干细胞，在一定的支持条件下允许其生长、增殖、生产为可替换的组织。另一方面，寻找细胞能够互相联结并形成分层结构的合适的支持条件，如基质或支架等非常必要。目前用于烧烫伤治疗的材料有很多种，如胶原，透明质酸、纤维蛋白和聚乳酸及其共聚物。 目的：讨论以新型的生物材料自体血浆为支架对自体成纤维细胞和角质化细胞生长、扩张、增殖的影响。 设计：建立一种真皮再生的方法，将自体成纤维细胞浸于人血浆基质中，排除各种影响样本安全性和排斥反应的问题，应用同样的方法在新的真皮上获取角质化细胞。 时间及地点：实验于2008年在意大利曼多瓦C. Poma医院动物工厂完成。 材料：人角质化细胞和成纤维细胞取自1例58岁乳房切除患者的皮肤碎片。实验得到C. Poma医院独立伦理委员会批准，患者知情同意。 方法：从自体活组织皮肤样本中分离人角质化细胞和成纤维细胞，置于培养瓶中增殖，随后将自体血浆作为皮肤移植形成构造的支架，免疫和免疫组织化学特征显示与正常皮肤相似。 主要观察指标：将血浆样本用甲醛固定，埋入石蜡，苏木精-伊红染色，用显微镜进行细胞计数。所有样本均经免疫组织化学评估。 结果：在血浆基质上获得了多层规则形状的角质化细胞和成纤维细胞，基底膜的形成说明自体血浆是角质化细胞和成纤维细胞的生长、分化、扩展的良好支架，真皮和表皮细胞联结重建皮肤移植与正常皮肤无异。 结论：血浆作为角质化细胞和成纤维细胞分化、扩展的支架表现出良好的性能，同时实验还特别发现成纤维细胞浓缩血浆可以暂时替代皮肤，也是角质化细胞生长的强有力的支架。此外血浆还具有廉价，易于制备等优点。自体角质化细胞和成纤维细胞及自体血浆的应用，可以避免血种类型的免疫排斥反应。这种治疗方法给有慢性缺损并且需要连续移植的患者带来了希望。 doi:10.3969/j.issn.1673-8225.2009.47.001     

大鼠骨髓间充质干细胞与多孔双相磷酸钙陶瓷支架体外黏附的实验研究

目的研究大鼠骨髓间充质干细胞(marrowmesenchymalstemcells,MSCs)诱导培养后在多孔双相磷酸钙(biphasiccalciumphosphate,BCP)陶瓷支架材料上的黏附和生长。方法SD大鼠MSCs经矿化诱导培养、扩增,具有成骨细胞表型后,与多孔BCP陶瓷支架及普通多孔羟基磷灰石(hydroxyapatite,HA)陶瓷支架体外复合培养,扫描电镜观察比较MSCs在两种材料支架表面的黏附数量和形态;同时以0.5、1.0、2.0、3.0和4.0×106/ml浓度细胞悬液接种于多孔BCP支架材料,检测适宜的接种浓度及单位体积支架材料可黏附MSCs数量。结果大鼠MSCs经诱导培养14d后,行矿化沉积茜素红染色、型胶原免疫细胞化学染色及碱性磷酸酶细胞化学染色,结果均为阳性。大鼠MSCs黏附于多孔BCP陶瓷上的细胞数(88.00±6.58)明显高于HA陶瓷组(39.00±3.65),两组比较差异有统计学意义(P<0.01)。当接种浓度为2.0×106/ml时,单位体积的陶瓷支架材料最多可黏附MSCs数量为1.28×107个/cm3,为细胞适宜接种浓度。结论大鼠MSCs在体外经矿化诱导培养可表达成骨细胞表型,细胞浓度为2.0×106/ml时与多孔BCP陶瓷支架材料具有良好的黏附能力。     

管状膨体聚四氟乙烯用于组织工程支架材料的动物实验研究

目的：研究膨体聚四氟乙烯(ePTFE)植入动物体内后与机体的关系。方法：管状膨体聚四氟乙烯两端闭合，内充DMEM培养液，埋入家兔皮下，观察宿主生命情况，于术后1、2、4、6周取出标本，行大体及光镜下观察。结果：家兔在植入膨体聚四氟乙烯材料及DMEM培养液后存活情况良好，DMEM培养液在1周时即已完全无色透明；4周时膨体聚四氟乙烯与周围组织有粘连，6周时粘连紧密；光镜下观察，各时间点材料间隙均可见着色，1周时可见少量淋巴细胞浸润，无血管及组织细胞。材料内壁未见细胞附着。结论：植入膨体聚四氟乙烯材料及少量DMEM培养液对宿主动物存活无影响；管内外液体可相互交通，管状膨体聚四氟乙烯可作为组织工程化尿道的支架材料。     

新型骨与软骨组织工程支架材料制备及其性能研究

目的：研究符合骨与软骨组织工程制备技术要求的新型支架复合材料；并确定其性能与结构优化设计的主要参数指标。方法：按不同CPPf(聚磷酸钙纤维）／PLL（L－聚乳酸）重量比及相同CPPfPLLA/NaCl颗粒重量比，采用溶铸颗粒沥取（Solventcasting particulte-leaching)法轩系列CPPf/PLLA支架复合材料；液体置换法，压缩性能测试及扫描电子显微镜观察其密度，孔隙度压缩模量及微结构特征；材料样品体外人工降解液直接浸渍法判定其生物降解性能，并观测其生物降解率，压缩碍及微结构由微孔海绵状过渡为纤维网状。随着支架材料在人工降解液中降解时间的延长，其降解率以0％－13．2％线性递增；压缩模量呈线性降低至1.10-2.78MP；材料横截面微结构则发生相应改变。结论 CPPf/PLLA支架复合材料具有高孔隙度的三维立体结构，良好的抗压缩性能和和解性能，经进一步优化设计后，可成为结构和性能符合各项要求的新与软骨组织工程支架材料。     

Engineering angiogenesis following spinal cord injury: a coculture of neural progenitor and endothelial cells in a degradable polymer implant leads to an increase in vessel density and formation of the blood–spinal cord barrier

Angiogenesis precedes recovery following spinal cord injury and its extent correlates with neural regeneration, suggesting that angiogenesis may play a role in repair. An important precondition for studying the role of angiogenesis is the ability to induce it in a controlled manner. Previously, we showed that a coculture of endothelial cells (ECs) and neural progenitor cells (NPCs) promoted the formation of stable tubes in vitro and stable, functional vascular networks in vivo in a subcutaneous model. We sought to test whether a similar coculture would lead to the formation of stable functional vessels in the spinal cord following injury. We created microvascular networks in a biodegradable two-component implant system and tested the ability of the coculture or controls (lesion control, implant alone, implant + ECs or implant + NPCs) to promote angiogenesis in a rat hemisection model of spinal cord injury. The coculture implant led to a fourfold increase in functional vessels compared with the lesion control, implant alone or implant + NPCs groups and a twofold increase in functional vessels over the implant + ECs group. Furthermore, half of the vessels in the coculture implant exhibited positive staining for the endothelial barrier antigen, a marker for the formation of the blood–spinal cord barrier. No other groups have shown positive staining for the blood–spinal cord barrier in the injury epicenter. This work provides a novel method to induce angiogenesis following spinal cord injury and a foundation for studying its role in repair.     

天然生物材料构建组织工程支架的研究进展

细胞培养支架材料是组织工程的重要研究内容之一.本文综述近年来几种典型天然生物材料构建组织工程支架的研究进展,并详细介绍了适用于天然生物材料制备组织工程支架的致孔方法.