Peptidoglycan (PG) is an arthritogenic bacterial cell wall component whose role in human osteoarthritis is poorly understood. The purpose of this study was to determine if PG is present in synovial tissue of osteoarthritis patients at the time of primary total knee arthroplasty (TKA), and if its presence is associated with inflammation and patient reported outcomes. Intraoperative synovial tissue and synovial fluid samples were obtained from 56 patients undergoing primary TKA, none of whom had history of infection. PG in synovial tissue was detected by immunohistochemistry (IHC) and immunofluorescence microscopy (IFM). Synovial tissue inflammation and fibrosis were assessed by histopathology and synovial fluid cytokine quantification. Primary human fibroblasts isolated from arthritis synovial tissue were stimulated with PG to determine inflammatory cytokine response. A total of 33/56 (59%) of primary TKA synovial tissue samples were positive for PG by IHC, and PG staining colocalized with markers of synovial macrophages and fibroblasts by IFM. Synovial tissue inflammation and elevated IL-6 in synovial fluid positively correlated with PG positivity. Primary human fibroblasts stimulated with PG secreted high levels of IL-6, consistent with ex vivo findings. Interestingly, we observed a significant inverse correlation between PG and age at time of TKA, indicating younger age at time of TKA was associated with higher PG levels. Peptidoglycan is commonly found in synovial tissue from patients undergoing TKA. Our data indicate that PG may play an important role in inflammatory synovitis, particularly in patients who undergo TKA at a relatively younger age.

中文翻译：

---

骨关节炎滑膜组织中的肽聚糖与关节炎症相关

肽聚糖（PG）是一种致关节炎的细菌细胞壁成分，其在人类骨关节炎中的作用尚不清楚。本研究的目的是确定骨关节炎患者在初次全膝关节置换术 (TKA) 时滑膜组织中是否存在 PG，以及其存在是否与炎症和患者报告的结果相关。术中采集56例初次TKA患者的滑膜组织和滑液样本，患者均无感染史。通过免疫组织化学（IHC）和免疫荧光显微镜（IFM）检测滑膜组织中的PG。通过组织病理学和滑液细胞因子定量评估滑膜组织炎症和纤维化。用 PG 刺激从关节炎滑膜组织中分离的原代人成纤维细胞，以确定炎症细胞因子反应。通过 IHC 检测，总共 33/56 (59%) 的原代 TKA 滑膜组织样本呈 PG 阳性，通过 IFM 检测，PG 染色与滑膜巨噬细胞和成纤维细胞标记物共定位。滑膜组织炎症和滑液中IL-6升高与PG阳性呈正相关。用 PG 刺激的原代人成纤维细胞分泌高水平的 IL-6，与体外研究结果一致。有趣的是，我们观察到 PG 与 TKA 时年龄之间存在显着的负相关，表明 TKA 时年龄较小与较高 PG 水平相关。肽聚糖常见于接受 TKA 的患者的滑膜组织中。我们的数据表明，PG 可能在炎症性滑膜炎中发挥重要作用，特别是在相对较年轻接受 TKA 的患者中。