Micrococcal nuclease-triggered antibiotics release: a prophylactic implant coating against S. aureus infections

微球菌核酸酶触发的抗生素释放：针对金黄色葡萄球菌感染的预防性植入物涂层

• 批准号: 10463666
• 负责人: Jie Song
• 金额: $ 48.75万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10463666
• 关键词: Address; Animals; Antibiotics; Bacteria; Biological Assay; Bone Cements; Bypass; Characteristics; Chemicals; Clinical; Debridement; Detection; Development; Dose; Drug resistance; Engineering; Ensure; Evaluation; Femur; Goals; Growth; Histology; Hydrogels; Implant; In Vitro; Infection; Infection prevention; Injections; Invaded; Lead; Linker-Oligonucleotide; Location; Mechanics; Methylation; Microbial Biofilms; Micrococcal Nuclease; Modeling; Modification; Monitor; Mus; Nucleotides; Oligonucleotides; Operative Surgical Procedures; Organ; Orthopedic Surgery; Orthopedics; Osteomyelitis; Pathology; Pharmaceutical Preparations; Prosthesis; Prosthesis-Related Infections; Rattus; Replacement Arthroplasty; Safety; Saline; Serum; Staphylococcus aureus; Staphylococcus aureus infection; Surface; System; Systemic infection; Technology; Testing; Thick; Time; Torsion; Vancomycin; bioluminescence imaging; bone; clinical translation; clinically relevant; comparative efficacy; cortical bone; drug development; ethylene dimethacrylate; implant associated infection; implant coating; in vivo; in vivo evaluation; infection rate; metallicity; microbial; nuclease; operation; phosphodiester; phosphorothioate; prevent; prophylactic; recurrent infection; side effect; standard care; success; surface coating

PROJECT SUMMARY/ABSTRACT Periprosthetic infections is one of the most serious complications in orthopedic surgeries, occurring in 1-4% of primary total joint replacement and up to 30% of revisions. Infections caused by Staphylococcus aureus (S. aureus), the most prevalent microbial culprit in orthopedic infections, are particularly hard to treat due to their tendency to form biofilms on implant and notorious ability to invade the canalicular network of surrounding bone. Existing prophylactic antibiotic deliveries involve high drug doses that are unsafe yet ineffective and could lead to the development of drug resistance. Utilizing an oligonucleotide linker labile to S. aureus micrococcal nuclease (MN) cleavage, we recently developed a hydrogel capable of on-demand release of covalently tethered vancomycin. When applied as a hydrogel coating to Ti6Al4V intramedullary (IM) pin and inserted to mouse femoral canal inoculated with S. aureus, the MN-triggered release of vancomycin timely killed the bacterial on implant surface and within IM space before they had a chance to colonize or invade surrounding bone, thereby preventing biofilm formation and osteomyelitis development in the 3 weeks examined. The covalent tethering dose of vancomycin in this coating was orders of magnitude lower than the typical prophylactic antibiotic content used clinically. The goal of the proposed study is to further engineer this exciting on-demand drug release system to enhance its serum stability and rigorously examine its efficacy in providing sustained protection against periprosthetic infections using two clinically relevant implant infection models. In Aim 1, the oligonucleotide linker is chemically modified by selective 2'-O-methylation and phosphorothioate modifications to achieved enhanced mammalian serum nuclease stability while maintaining necessary sensitivity to MN cleavage. In Aim 2, the in vitro optimized nucleotide linker will be implemented in MN-sensitive hydrogel coating and applied to Ti6Al4V IM pins for on-demand delivery of vancomycin. The efficacy and safety of this prophylactic coating in providing timely and sustained protection against S. aureus periprosthetic infections will be rigorously evaluated over 6 months using a rat femoral canal infection model. In Aim 3, the efficacy of this on-demand antibiotic release strategy in reducing the high periprosthetic infection rates following surgical debridement of previously infected rat femoral canal will be examined using a rat IM implant revision surgery model. The degree of infections as a function of pin coating and bioluminescent S. aureus inoculation are longitudinally monitored by bioluminescent imaging and µCT quantification of cortical bone thickening at 2 weeks, 1, 2, 3 and 6 months, and by end-point quantification of bacteria on the retrieved pin, torsion test of explanted femur and femoral histology at 1, 3 and 6 months. Long-term safety of the coating is examined by systemic organ pathology at the endpoints. Systemic injections of vancomycin at a dose several hundred-fold higher than that in the prophylactic coating are carried out in a subset of infected animals receiving uncoated IM pins to allow direct comparison of the efficacy of this prophylactic coating vs. that of the standard care. Achieving more sustained protection against periprosthetic infections or recurrent infections than systemic vancomycin injections will be considered a success while achieving extended protection for 6 months without local and systemic side effects will be considered exceptional. If successfully validated, the timely and sustained eradication of bacteria enabled by MN-triggered vancomycin release could bring together safety and efficacy in addressing the daunting challenge of orthopedic implant-associated infections by bypassing the notoriously hard-to-treat biofilms and osteomyelitis.

项目总结/摘要 假体周围感染是骨科手术中最严重的并发症之一， 初次全关节置换和高达30%的翻修。由金黄色葡萄球菌（S. 金黄色葡萄球菌），骨科感染中最普遍的微生物罪魁祸首，由于其 倾向于在植入物上形成生物膜，并且具有侵入周围组织的小管网络的能力 骨头现有的预防性抗生素递送涉及高药物剂量，其不安全但无效， 会导致抗药性的产生利用对S.金黄色 微球菌核酸酶（MN）切割，我们最近开发了一种水凝胶，能够按需释放 共价连接的万古霉素。当作为水凝胶涂层应用于Ti6 Al 4V髓内（IM）销时， 插入接种S.金黄色葡萄球菌，MN触发的万古霉素的及时释放 在植入物表面和IM间隙内的细菌有机会定植或侵入之前将其杀死 周围的骨，从而防止生物膜形成和骨髓炎的发展，在3周内 考察万古霉素在该涂层中的共价束缚剂量比在该涂层中的万古霉素的共价束缚剂量低几个数量级。 临床上常用的典型预防性抗生素含量。拟议研究的目标是进一步设计这一点 激发按需药物释放系统，以增强其血清稳定性，并严格检查其在 使用两种临床相关的植入物感染提供持续保护，防止假体周围感染 模型在目的1中，寡核苷酸接头通过选择性2 '-O-甲基化进行化学修饰， 硫代磷酸酯修饰以实现增强的哺乳动物血清核酸酶稳定性，同时维持 对MN裂解的必要敏感性。在目标2中，体外优化的核苷酸接头将在以下实施： MN敏感性水凝胶涂层，应用于Ti6 Al 4V IM针，用于按需输送万古霉素。的 该预防性涂层在提供及时和持续的抗链球菌保护方面的有效性和安全性。金黄色 将使用大鼠股骨髓腔感染模型在6个月内对假体周围感染进行严格评估。在 目的3，这种按需抗生素释放策略在减少高假体周围感染方面的有效性 将使用大鼠IM检查对先前感染的大鼠股管进行手术清创后的比率 植入物翻修手术模型。感染的程度作为针涂层和生物发光S的函数。 通过生物发光成像和皮质µCT量化纵向监测金黄色葡萄球菌接种 在2周、1个月、2个月、3个月和6个月时的骨增厚，并通过对回收的 在1、3和6个月时，对固定股骨和股骨组织学进行销钉、扭转试验。涂层的长期安全性 在终点时通过全身器官病理学检查。全身注射万古霉素， 比预防性涂层中高几百倍的剂量在感染动物的亚组中进行 接受无涂层IM销，以直接比较该预防性涂层与 标准护理更持久地预防假体周围感染或复发性感染 全身万古霉素注射将被认为是成功的，同时实现了6 没有局部和全身副作用的月将被视为例外。如果验证成功， 通过MN触发的万古霉素释放能够及时和持续地根除细菌， 通过以下方法解决骨科植入物相关感染的严峻挑战的安全性和有效性 绕过了难以治疗的生物膜和骨髓炎