Tian Liangjie, Tan Zilin, Yang Yusheng, Liu Shencai, Yang Qingfeng, Tu Yuesheng, Chen Jialan, Guan Hongye, Fan Lei, Yu Bin, Chen Xianhui, Hu Yanjun
Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province 510515, China.
Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province 510515, China.
Acta Biomater. 2023 Oct 1;169:209-227. doi: 10.1016/j.actbio.2023.07.039. Epub 2023 Jul 28.
At present, surgical debridement and systematic administration of antibiotics represent the mainstay of treatment for chronic osteomyelitis. However, it is now understood that Staphylococcus aureus (S. aureus) can survive within excessively polarized M2 macrophages and evade antibiotics, accounting for the high recurrence of chronic osteomyelitis. Effective treatments for intracellular infection have rarely been reported. Herein, we designed an in situ sprayed liposomes hydrogels spray with macrophage-targeted effects and the ability to reverse polarization and eradicate intracellular bacteria to reduce the recurrence of osteomyelitis. Resiquimod (R848)-loaded and phosphatidylserine (PS)-coating nanoliposomes were introduced into fibrinogen and thrombin to form the PSL-R848@Fibrin spray. Characterization and phagocytosis experiments were performed to confirm the successful preparation of the PSL-R848@Fibrin spray. Meanwhile, in vitro cell experiments validated its ability to eliminate intracellular S. aureus by reprogramming macrophages from the M2 to the M1 phenotype. Additionally, we established a chronic osteomyelitis rat model to simulate the treatment and recurrence process. Histological analysis demonstrated a significant increase in M1 macrophages and the elimination of intracellular bacteria. Imaging revealed a significant decrease in osteomyelitis recurrence. Overall, the liposome hydrogels could target macrophages to promote antibacterial properties against intracellular infection and reduce the recurrence of chronic osteomyelitis, providing the foothold for improving the outcomes of this patient population. STATEMENT OF SIGNIFICANCE: Chronic osteomyelitis remains a high recurrence although undergoing traditional treatment of debridement and antibiotics. S. aureus can survive within the excessively polarized M2 macrophages to evade the effects of antibiotics. However, few studies have sought to investigate effective intracellular bacteria eradication. Herein, we designed a macrophage-targeted R848-containing liposomes fibrin hydrogels spray (PSL-R848@Fibrin) that can reprogram polarization of macrophages and eradicate intracellular bacteria for osteomyelitis treatment. With great properties of rapid gelation, strong adhesion, high flexibility and fit-to-shape capacity, the facile-operated immunotherapeutic in-situ-spray fibrin hydrogels exhibited huge promise of reversing polarization and fighting intracellular infections. Importantly, we revealed a hitherto undocumented treatment strategy for reducing the recurrence of chronic osteomyelitis and potentially improving the prognosis of chronic osteomyelitis patients.
目前，手术清创和系统性使用抗生素是慢性骨髓炎治疗的主要手段。然而，现在人们认识到金黄色葡萄球菌（S. aureus）能够在过度极化的M2巨噬细胞内存活并逃避抗生素作用，这是慢性骨髓炎高复发率的原因。针对细胞内感染的有效治疗方法鲜有报道。在此，我们设计了一种具有巨噬细胞靶向作用、能够逆转极化并根除细胞内细菌以降低骨髓炎复发率的原位喷洒脂质体水凝胶喷雾剂。将负载瑞喹莫德（R848）并包被磷脂酰丝氨酸（PS）的纳米脂质体引入纤维蛋白原和凝血酶中，形成PSL-R848@Fibrin喷雾剂。通过表征和吞噬实验证实了PSL-R848@Fibrin喷雾剂的成功制备。同时，体外细胞实验验证了其通过将巨噬细胞从M2表型重编程为M1表型来消除细胞内金黄色葡萄球菌的能力。此外，我们建立了慢性骨髓炎大鼠模型来模拟治疗和复发过程。组织学分析表明M1巨噬细胞显著增加且细胞内细菌被清除。影像学检查显示骨髓炎复发率显著降低。总体而言，脂质体水凝胶能够靶向巨噬细胞，增强对细胞内感染的抗菌性能并降低慢性骨髓炎的复发率，为改善这类患者的治疗效果提供了依据。重要性声明：尽管接受了传统的清创和抗生素治疗，但慢性骨髓炎的复发率仍然很高。金黄色葡萄球菌能够在过度极化的M2巨噬细胞内存活，以逃避抗生素的作用。然而，很少有研究致力于探究有效的根除细胞内细菌的方法。在此，我们设计了一种靶向巨噬细胞的含R848脂质体纤维蛋白水凝胶喷雾剂（PSL-R848@Fibrin），它能够重编程巨噬细胞的极化并根除细胞内细菌用于骨髓炎治疗。这种易于操作的免疫治疗原位喷洒纤维蛋白水凝胶具有快速凝胶化、强粘附性、高柔韧性和贴合形状的能力等优异特性，在逆转极化和对抗细胞内感染方面展现出巨大潜力。重要的是，我们揭示了一种此前未被记录的治疗策略，可降低慢性骨髓炎的复发率，并有可能改善慢性骨髓炎患者的预后。
