Electromechanical Stimuli on the Development of Engineered Myotendinous Junction

描述（由申请人提供）：终末期器官衰竭或组织损失是医学上最具破坏性和代价最高的问题之一。据估计，每年进行800万例手术，每年的医疗保健费用超过4000亿美元。器官和组织替代受到供体可用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，但组织置换目前已用于皮肤移植和心脏瓣膜置换。目前的工程肌肉模型是在合成锚上制造的，并且受到培养中的肌肉细胞与所使用的合成材料界面的限制。通常，随着工程化肌肉构造成熟并产生更多的被动力，肌管从合成锚上分离并收缩成细胞球，这对于体外研究肌肉功能或体内移植是无用的。具有功能性肌腱连接（MTJ）的工程化肌肉骨骼组织的创建将扩大工程化肌肉作为发育肌肉生物学、肌肉药理学和用于移植患病或受损肌肉的模型的有用性。我们的工作假设是，结合应用的电活动和机械应变引入功能性MTJ将导致肌肉和肌腱中更先进的表型;工程肌肉中的力产生增加;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将是设计，制造和评估的结构和收缩特性的三维（3D）工程组织含有MTJ，一个功能性肌肉骨骼结构所需的主要组织接口。我们将建立骨骼肌结构与工程肌腱结构（ETC）或成人（ART）或胎鼠尾（FRT）肌腱段共培养。我们假设肌腱组织和肌肉的共培养将产生具有在力产生期间保持完整的可行的肌肉-肌腱界面的构造，并且将促进构造内的肌细胞分化。我们还建议使用生物反应器将肌腱-肌肉结构置于物理环境中，该物理环境模拟后肢肌肉的应力、应变和收缩活动，类似于体内发现的那些。

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.