Commentary on Some Recent Theses Relevant to Combating Aging: December 2010
Commentary on Some Recent Theses Relevant to Combating Aging: December 2010
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对最近一些与抗击衰老相关的论文的评论：2010 年 12 月
DOI：
10.1089/rej.2010.1147
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
A. D. Grey
中科院分区：
文献类型：
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作者：
A. D. Grey
连续的纳米结构，如电纺纳米纤维，包埋蛋白质，可以协同呈现的形貌和生物化学信号的细胞组织工程应用。本论文采用同轴静电纺丝技术制备具有单轴形貌的组织工程支架，并将其作为一种有效包封和释放蛋白质和生物活性物质的手段。在第一个具体目标中，生产了用BSA和生长因子包封的对齐的聚（[vareplavine]-己内酯）纳米纤维，以证明控释和生物活性保留特性。通过在纤维的壳中掺入聚（乙二醇）作为致孔剂来实现对释放动力学的控制。PEG以浓度和分子量依赖性方式浸出，导致BSA释放半衰期范围为1-20天。第二个具体目标介绍了病毒和细菌细胞包裹的静电纺丝纤维的制造，以实现独特的生物功能化。编码绿色荧光蛋白基因的腺病毒通过同轴静电纺丝被有效地封装到聚-（[vareplutamine]-己内酯）纤维的核心中，随后通过致孔剂介导的过程释放。封装的细菌细胞被限制在不同芯尺寸的纤维中，这提供了自由移动的水性芯环境，并允许细菌在纤维内增殖。在第三个具体的目标，骨骼肌成肌细胞的分化对齐静电纺丝聚氨酯纤维和机电刺激的存在下进行了系统的研究。与随机PU纤维和膜上培养的成肌细胞相比，对齐PU纤维上培养的成肌细胞显示出更明显的伸长、更好的对齐、收缩蛋白的上调和更高的横纹肌管百分比。在最后一个具体目标中，将同轴电纺纤维的控释方面与骨骼组织工程相结合，以用作治疗血友病的治疗性植入物。采用非病毒组织工程方法刺激局部淋巴或血管系统，以增强FVIII产生植入物附近的转运，从而为血友病A提供有效和持续的治疗。从分离的成肌细胞工程化稳定的产生FVIII的克隆，并在对齐的释放蛋白质的电纺纤维上培养以形成骨骼肌管。植入的构建体迅速与宿主组织整合，并选择性地诱导血管生成或淋巴管生成作为封装的生长因子的结果。诱导血管生成的构建体显著增强了产生的FVIII的转运，并在两个月内实现了血友病表型校正。使用同轴电纺纤维作为受控递送和组织工程构建体进一步推动了对更复杂和医学相关的植入物支架设计的持续追求。备注：多年来，在用于组织工程的人工细胞外基质材料的开发中已经进行了许多工作，但是这样的材料仍然缺乏重要的特征。在这项研究中讨论的支架最令人兴奋的方面是封装活细胞的能力：这预示着工程细菌分泌可溶性因子并将其整合到支架中的可能性，以造福于主要组成组织的人类细胞。
Continuous nanostructures, such as electrospun nanofibers, embedded with proteins may synergistically present the topographical and biochemical signals to cells for tissue engineering applications. In this dissertation, co-axial electrospinning is introduced as a mean to efficiently encapsulate and release protein and live entities while producing a tissue engineering scaffold with uniaxial topography. In the first specific aim, aligned poly ([varepsilon]-caprolactone) nanofibers encapsulated with BSA and growth factors were produced to demonstrate controlled release and bioactivity retention properties. Control over release kinetics is achieved by incorporation of poly (ethylene glycol) as a porogen in the shell of the fibers. PEG leaches out in a concentration and molecular weight dependent fashion, leading to BSA release half-lives that range from 1-20 days. The second specific aim introduces the fabrication of virus and bacterial cell encapsulated electrospun fibers to achieve unique biological functionalization. Adenovirus encoding the gene for green fluorescent protein was efficiently encapsulated into the core of poly-([varepsilon]-caprolactone) fibers through co-axial electrospinning and subsequently released via the porogen-mediated process. Encapsulated bacterial cells were confined to fibers of varying core sizes, which provided an aqueous core environment for free mobility and allowed the bacterias to proliferate within the fibers. In the third specific aim, the differentiation of skeletal myoblasts on aligned electrospun polyurethane fibers and in the presence of electromechanical stimulation were systematically studied. Skeletal myoblasts cultured on aligned PU fibers showed more pronounced elongation, better alignment, upregulation of contractile proteins and higher percentage of striated myotubes compared to those cultured on random PU fibers and film. In the last specific aim, the controlled release aspect of co-axial electrospun fibers were combined with skeletal tissue engineering to serve as a therapeutic implant for the treatment of hemophilia. A non-viral, tissue engineering approach were taken to stimulate local lymphatic or vascular system in order to enhance transport near the FVIII-producing implants to provide effective and sustained treatment for hemophilia A. Stable FVIII-producing clones were engineered from isolated myoblasts and cultured on aligned, protein-releasing electrospun fibers to form skeletal myotubes. The implanted construct rapidly integrated with host tissue and selectively induced angiogenesis or lymphangiogenesis as a result of the encapsulated growth factors. Constructs inducing angiogenesis significantly enhanced the transport of produced FVIII and achieved hemophilia phenotypic correction over two months. The use of co-axial electrospun fibers to serve as controlled delivery and tissue engineering construct furthers the continued pursue of a more sophisticated and medically relevant implant scaffold design. Comment: Much work has occurred, over many years, in the development of artificial extracellular matrix materials for tissue engineering, but such materials still lack important features. The most exciting aspect of the scaffolds discussed in this study is the ability to encapsulate live cells: this heralds the possibility of engineering bacteria to secrete soluble factors and incorporating them into scaffolds for the benefit of the human cells of which the tissue in question is mainly composed.