Cellular mechanisms for the degeneration and aging of human rotator cuff tears

摘要 肩袖肌肉允许手臂和肩膀的运动， 易随年龄而撕裂。与骨骼肌相关的肌肉退化是令人担忧的， 美国人口老龄化给我们的医疗保健系统带来负担。虽然手术干预策略， 存在肩袖撕裂，在许多情况下，肌肉在手术后不能再生，导致 根据研究，10-50%患者的再撕裂率显著且可变。风险 再撕裂的因素包括年龄、性别和术前撕裂大小;然而， 每个风险因素都是未知的。此外，在细胞和分子水平，肌纤维，卫星， 细胞、基质细胞和免疫细胞动态调节再生过程。而其 已知的细胞群转移发生与年龄，性别和肩袖撕裂，没有研究评估 细胞病理学在患者群体中的动态变化。在这份提案中，希克斯和古普塔 实验室将检验两个假设：1）慢性人类RCT的细胞成分抑制SC 通过炎症因子和/或纤维化的再生，和2）慢性人肌肉损伤 导致SC池的耗竭和衰老，从而导致加速退化。 在目标1中，我们将使用高维成像质量细胞术来定量免疫基质细胞， 肌肉异质性以及衰老和活化的表型标记。成像质谱 流式细胞术可以在单个组织上实现多达40种抗体的多重染色， 复杂的细胞表型和组织病理学分类的显着改进， 临床组织样本。我们希望能找到按年龄分类的独特分子特征， 性别和Goutallier等级，从而提供肌肉再生的预测指标 在肩袖撕裂之后在目标2中，我们将测试在体外培养的人骨髓基质干细胞和基质细胞的功能状态。 体外使用三种主要测定，衰老：通过活细胞成像，转分化：通过纤维化 和脂肪形成刺激因子，以及基质细胞对肌肉再生的调节：通过共 培养具有卫星细胞的基质群。这些检测的结果将指导使用 体外抗衰老或抗纤维化药物。这项研究是了解 内在和外在缺陷的骨骼肌修复，并将阐明这两个预测 肩袖撕裂手术的结果，并确定新的治疗方法，可以改善肌肉 再生老化和肌肉撕裂。

Abstract The rotator cuff muscles allow for movement of the arm and shoulder and are particularly susceptible to tear with age. Age-related muscle degeneration is alarming as an ever-increasing aging US population burdens our health care system. While surgical intervention strategies for rotator cuff tears exist, in many instances the muscle fails to regenerate after surgery, leading to a significant and variable rate of retear for 10-50% of patients, depending on the study. Risk factors for retear include age, gender, and pre-operative tear size; however, the interdependency of each risk factor is unknown. Moreover, at the cellular and molecular level, myofibers, satellite cells, stromal cells, and immune cells dynamically regulate the regeneration processes. While its known cell populations shift occurs with age, gender, and rotator cuff tear, no study has evaluated the dynamics of cell pathology across patient populations. In this proposal, the Hicks and Gupta labs will test two hypothesis that 1) the cellular composition of chronic human RCTs inhibits SC regeneration through inflammatory factors and/or fibrosis, and 2) chronic human muscle injury leads to exhaustion and senescence of the SC pool, thereby leading to accelerated degeneration. In Aim 1, we will use high-dimensional imaging mass cytometry to quantify immune-stromal- muscle heterogeneity as well as phenotypic markers of senescence and activation. Imaging mass cytometry can achieve multiplex staining upwards of 40 antibodies on a single tissue, enabling significant refinement of complex cellular phenotypes and histopathological classification of clinical tissue samples. We expect to find will unique molecular signatures clustered by age, gender, and Goutallier grade, thus providing predictive measures of muscle regeneration following rotator cuff tear. In Aim 2, we will test the functional status of SCs and stromal cells in vitro using three main assays, senescence: via live cell imaging, trans differentiation: via fibrotic and adipogenic stimulating factors, and stromal cell regulation of muscle regeneration: via co- culturing stromal populations with satellite cells. Results from these assays will guide the use of anti-senescent or anti-fibrotic drugs in vitro. This study serves as a basis for understanding the intrinsic and extrinsic defects in skeletal muscle repair and will shed light on both predicting outcomes of rotator cuff tear surgery and identifying new treatments that could improve muscle regeneration for aging and muscle tears.