Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong, China.
Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
Arthritis Res Ther. 2021 Apr 10;23(1):110. doi: 10.1186/s13075-021-02457-3.
Osteoarthritis (OA) has long been regarded as a disease of cartilage degeneration, whereas mounting evidence implies that low-grade inflammation contributes to OA. Among inflammatory cells involved, macrophages play a crucial role and are mediated by the local microenvironment to exhibit different phenotypes and polarization states. Therefore, we conducted a systematic review to uncover the phenotypic alterations of macrophages during OA and summarized the potential therapeutic interventions via modulating macrophages.
A systematic review of multiple databases (PubMed, Web of Science, ScienceDirect, Medline) was performed up to February 29, 2020. Included articles were discussed and evaluated by two independent reviewers. Relevant information was analyzed with a standardized and well-designed template.
A total of 28 studies were included. Results were subcategorized into two sections depending on sources from human tissue/cell-based studies (12 studies) and animal experiments (16 studies). The overall observation indicated that M1 macrophages elevated in both synovium and circulation during OA development, along with lower numbers of M2 macrophages. The detailed alterations of macrophages in both synovium and circulation were listed and analyzed. Furthermore, interventions against OA via regulating macrophages in animal models were highlighted.
This study emphasized the importance of the phenotypic alterations of macrophages in OA development. The classical phenotypic subcategory of M1 and M2 macrophages was questionable due to controversial and conflicting results. Therefore, further efforts are needed to categorize macrophages in an exhaustive manner and to use advanced technologies to identify the individual roles of each subtype of macrophages in OA.
骨关节炎（OA）长期以来一直被认为是一种软骨退化疾病，而越来越多的证据表明，低水平炎症有助于 OA 的发生。在涉及的炎症细胞中，巨噬细胞起着至关重要的作用，并受局部微环境的影响而表现出不同的表型和极化状态。因此，我们进行了一项系统综述，以揭示 OA 过程中巨噬细胞的表型改变，并总结通过调节巨噬细胞的潜在治疗干预措施。
对多个数据库（PubMed、Web of Science、ScienceDirect、Medline）进行了系统综述，截至 2020 年 2 月 29 日。由两位独立评审员对纳入的文章进行讨论和评估。使用标准化和精心设计的模板对相关信息进行分析。
共纳入 28 项研究。结果根据来源分为两部分，分别为基于人组织/细胞的研究（12 项研究）和动物实验（16 项研究）。总的观察结果表明，在 OA 发展过程中，滑膜和循环中的 M1 巨噬细胞增多，而 M2 巨噬细胞数量减少。列出并分析了滑膜和循环中巨噬细胞的详细变化。此外，还强调了通过调节动物模型中的巨噬细胞来干预 OA。
本研究强调了巨噬细胞表型改变在 OA 发展中的重要性。由于存在有争议和相互矛盾的结果，经典的 M1 和 M2 巨噬细胞表型亚类值得怀疑。因此，需要进一步努力以详尽的方式对巨噬细胞进行分类，并使用先进技术来确定每种巨噬细胞亚型在 OA 中的个体作用。
