Pearson Joseph J, Mao Jiahui, Temenoff Johnna S
bioRxiv. 2024 Aug 21:2024.08.20.608812. doi: 10.1101/2024.08.20.608812.
Muscle degeneration after rotator cuff tendon tear is a significant clinical problem. In these experiments, we developed a poly(ethylene glycol)-based injectable granular hydrogel containing two heparin derivatives (fully sulfated (Hep) and fully desulfated (Hep-)) as well as a matrix metalloproteinase-sensitive peptide to promote sustained release of Tumor Necrosis Factor Stimulated Gene 6 (TSG-6) over 14+ days in a rat model of rotator cuff muscle injury. The hydrogel formulations demonstrated similar release profiles , thus facilitating comparisons between delivery from heparin derivatives on level of tissue repair in two different areas of muscle (near the myotendious junction (MTJ) and in the muscle belly (MB)) that have been shown previously to have differing responses to rotator cuff tendon injury. We hypothesized that sustained delivery of TSG-6 would enhance the anti-inflammatory response following rotator cuff injury through macrophage polarization, and that release from a fully sulfated heparin derivative (Hep) would potentiate this effect throughout the muscle. Inflammatory/immune cells, satellite cells, and fibroadipogenic progenitor cells, were analyzed by flow cytometery 3 and 7 days after injury and hydrogel injection, while metrics of muscle healing were examined via immunohistochemistry up to Day 14. Results showed controlled delivery of TSG-6 from Hep caused heightened macrophage response (Day 14 macrophages, 4.00 ± 1.85% single cells, M2a, 3.27 ± 1.95% single cells) and increased markers of early muscle regeneration (embryonic heavy chain staining) by Day 7, particularly in the MTJ region of the muscle, compared to release from desulfated heparin hydrogels. This work provides a novel strategy for localized, controlled delivery of TSG-6 to enhance muscle healing after rotator cuff tear.
Rotator cuff tear is a significant problem that can cause muscle degeneration. In this study, a hydrogel particle system was developed for sustained release of an anti-inflammatory protein, Tumor Necrosis Factor Stimulated Gene 6 (TSG-6), to injured muscle. Release of the protein from a fully sulfated heparin hydrogel-based carrier demonstrated greater changes in amount inflammatory cells and more early regenerative effects than a less-sulfated carrier. Thus, this work provides a novel strategy for localized, controlled delivery of an anti-inflammatory protein to enhance muscle healing after rotator cuff tear.
肩袖肌腱撕裂后的肌肉退化是一个严重的临床问题。在这些实验中，我们开发了一种基于聚乙二醇的可注射颗粒水凝胶，其中含有两种肝素衍生物（全硫酸化（Hep）和全脱硫酸化（Hep-））以及一种基质金属蛋白酶敏感肽，以促进肿瘤坏死因子刺激基因6（TSG-6）在肩袖肌肉损伤大鼠模型中持续释放超过14天以上。水凝胶制剂表现出相似的释放曲线，从而便于比较两种不同肌肉区域（肌肌腱交界处（MTJ）附近和肌腹（MB））中肝素衍生物递送对组织修复水平的影响，此前已表明这两个区域对肩袖肌腱损伤有不同反应。我们假设TSG-6的持续递送将通过巨噬细胞极化增强肩袖损伤后的抗炎反应，并且全硫酸化肝素衍生物（Hep）的释放将在整个肌肉中增强这种作用。在损伤和水凝胶注射后3天和7天，通过流式细胞术分析炎症/免疫细胞、卫星细胞和成纤维脂肪生成祖细胞，而在第14天之前通过免疫组织化学检查肌肉愈合指标。结果表明，与脱硫酸化肝素水凝胶的释放相比，Hep对TSG-6的可控递送导致巨噬细胞反应增强（第14天巨噬细胞，单细胞4.00±1.85%，M2a，单细胞3.27±1.95%），并在第7天增加早期肌肉再生标志物（胚胎重链染色），特别是在肌肉的MTJ区域。这项工作为局部、可控地递送TSG-6以增强肩袖撕裂后的肌肉愈合提供了一种新策略。
肩袖撕裂是一个可导致肌肉退化的重大问题。在本研究中，开发了一种水凝胶颗粒系统，用于将抗炎蛋白肿瘤坏死因子刺激基因6（TSG-6）持续释放到受伤肌肉中。与硫酸化程度较低的载体相比，基于全硫酸化肝素水凝胶的载体释放蛋白质显示出炎症细胞数量的更大变化和更多的早期再生效应。因此，这项工作为局部、可控地递送抗炎蛋白以增强肩袖撕裂后的肌肉愈合提供了一种新策略。
