Centre of Biological Engineering (CEB), University of Minho, Braga, Portugal.
LABBELS, Associate Laboratory, Braga Guimarães, Portugal.
J Biomed Mater Res A. 2022 Nov;110(11):1786-1800. doi: 10.1002/jbm.a.37432. Epub 2022 Aug 9.
A local drug delivery system that attempts to find a suitable balance between antimicrobial and regenerative actions was developed for osteomyelitis treatment (OM). This system combines the angiogenic and immunomodulatory peptide LLKKK18 (LL18) and vancomycin hydrochloride (VH), loaded into an injectable oxidized dextrin (ODEX)-based hydrogel (HG). In vitro cytotoxicity was analyzed in MC3T3-E1 pre-osteoblasts and erythrocytes. The kinetics of LL18 release was studied. Antimicrobial activity was assessed in vitro against a clinical Methicillin-Resistant Staphylococcus aureus (MRSA) strain. A rat model of acute OM was developed by direct inoculation into a tibia defect, concomitantly with the implantation of the drug-loaded HG. The local bioburden was quantified and damage in surrounding tissues was examined histologically. In vitro, ODEX-based HG displayed a safe hemolytic profile. Half of LL18 (53%) is released during the swelling phase at physiological pH, then being gradually released until complete HG degradation. LL18-loaded HG at 300 μM was the most effective peptide formulation in decreasing in vivo infection among concentrations ranging from 86 to 429 μM. The histopathological scores observed in vivo varied with the LL18 concentration in a dose-dependent manner. VH at 28 mM completely eradicated bacteria, although with substantial tissue injury. We have found that sub-millimolar doses of VH combined with LL18 at 300 μM may suffice to eradicate the infection, with reduced tissue damage. We propose an easy-to-handle, shape-fitting HG formulation with the potential to treat MRSA-infected bone with low VH doses associated with LL18.
为治疗骨髓炎（OM），开发了一种尝试在抗菌和再生作用之间找到合适平衡的局部药物递送系统。该系统将血管生成和免疫调节肽 LLKKK18（LL18）和盐酸万古霉素（VH）结合到可注射的氧化糊精（ODEX）基水凝胶（HG）中。在 MC3T3-E1 前成骨细胞和红细胞中分析了体外细胞毒性。研究了 LL18 的释放动力学。体外评估了针对临床耐甲氧西林金黄色葡萄球菌（MRSA）菌株的抗菌活性。通过直接接种到胫骨缺损中并同时植入载药 HG，建立了急性 OM 大鼠模型。定量了局部生物负荷，并通过组织学检查了周围组织的损伤。在体外，ODEX 基 HG 显示出安全的溶血特性。在生理 pH 下的肿胀阶段，有一半的 LL18（53%）释放，然后逐渐释放，直到完全 HG 降解。在浓度范围为 86 至 429 μM 时，300 μM 的 LL18 载 HG 是降低体内感染最有效的肽制剂。体内观察到的组织病理学评分与 LL18 浓度呈剂量依赖性变化。28 mM 的 VH 完全消除了细菌，但会造成大量组织损伤。我们发现，将亚毫摩尔剂量的 VH 与 300 μM 的 LL18 结合使用，可能足以消除感染，同时减少组织损伤。我们提出了一种易于处理、形状合适的 HG 配方，具有用低剂量 VH 联合 LL18 治疗 MRSA 感染骨骼的潜力。
