Electromechanical Stimuli on the Development of Engineered Myotendinous Junction

描述(申请人提供)：终末期器官衰竭或组织丢失是医学上最具破坏性和代价最高的问题之一。据估计，每年要进行800万次手术，每年的医疗费用超过4000亿美元。器官和组织替代受到供体可获得性和免疫排斥的限制。虽然整个器官置换还需要很多年才能成为现实，但组织置换目前正被用于皮肤移植和心脏瓣膜置换。目前的工程化肌肉模型是在合成支架上制造的，并受到培养中的肌肉细胞与所使用的合成材料之间的良好接口的限制。一般来说，随着工程化肌肉结构的成熟和发展出更多的被动力，肌管从合成的锚上分离出来，收缩成一团细胞，这对体外研究肌肉功能或体内移植都是无用的。具有功能性肌腱连接(MTJ)的工程化肌肉骨骼组织的建立将扩大工程化肌肉作为发育肌肉生物学、肌肉药理学和疾病或受损肌肉移植的模型的有用性。我们的工作假设是，功能性MTJ的引入与施加的电活动和机械应变一起将导致肌肉和肌腱中更高级的表型；工程化肌肉中的力量产生增加；以及更强大和更发达的组织界面。我们在这项研究中的目的是设计、制造和评估含有MTJ的三维(3D)工程组织的结构和收缩特性，MTJ是功能性肌肉骨骼构造所需的主要组织界面之一。我们将构建与工程化肌腱构建(ETC)或成人肌腱(ART)或胎鼠尾部肌腱(FRT)共培养的骨骼肌构建物。我们假设，肌腱组织和肌肉的共培养将产生具有可存活的肌肉-肌腱界面的构造物，这些肌腱界面在产生力量的过程中保持完好，并将促进构造物中的肌细胞分化。我们还建议使用生物反应器将肌腱-肌肉结构放置到物理环境中，模拟类似于体内发现的后肢肌肉的应力、应变和收缩活动。

DESCRIPTION (provided by applicant): End-stage organ failure or tissue loss is one of the most devastating and costly problems in medicine. Eight million surgeries are estimated to be performed each year incurring a health care cost of more than $400 billion annually. Organ and tissue replacement is limited by donor availability and immuno-rejection. While whole organ replacement is many years from becoming a reality, tissue replacement is currently being used for skin grafting and heart valve replacement. Current models for engineered muscle are fabricated on synthetic anchors and are limited by how well the muscle cells in culture interface with the synthetic material used. In general, as the engineered muscle construct matures and develops more passive force, the myotubes detach from the synthetic anchor and contract into a ball of cells which is useless for studying muscle function in vitro or transplantation in vivo. The creation of an engineered musculoskeletal tissue with a functional myotendinous junction (MTJ) will expand the usefulness of engineered muscle as a model for developmental muscle biology, muscle pharmacology, and for transplantation of diseased or damaged muscle. Our working hypothesis is that the introduction of functional MTJ in conjunction with applied electrical activity and mechanical strain will lead to a more advanced phenotype in the muscle and tendon; increased force production in the engineered muscles; and stronger and more developed tissue interfaces. Our purpose in this study will be to design, fabricate, and evaluate the structural and contractile characteristics of three-dimensional (3D) engineered tissues containing MTJ, one of the principal tissue interfaces required for a functional musculoskeletal construct. We will build skeletal muscle constructs co- cultured with engineered tendon constructs (ETC) or segments of adult (ART) or fetal rat tail (FRT) tendon. We hypothesize that the co-culture of tendon tissue and muscle will produce constructs with viable muscle- tendon interfaces that remain intact during force production and that will advance the myocyte differentiation within the construct. We also propose to use bioreactors to place the tendon-muscle constructs into physical environments which simulate the stress, strain, and contractile activity of hind limb muscles resembling those found in vivo.