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

基本信息

批准号：
10684948
负责人：
Jie Song
金额：
$ 48.94万
依托单位：
UNIV OF MASSACHUSETTS MED SCH WORCESTER
依托单位国家：
美国
项目类别：
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/10684948
关键词：
Address Animals Antibiotics Bacteria Biological Assay Bone Cements Bypass Characteristics Chemicals Clinical Debridement Detection Development Dose Engineering Ensure Evaluation Femur Goals Growth Histology Hydrogels Implant In Vitro Incubated Infection Infection prevention Injections Invaded Location Mechanics Methylation Microbial Biofilms Micrococcal Nuclease Modeling Modification Monitor Mus Nucleotides Oligonucleotides Operative Surgical Procedures Organ Orthopedic Surgery Orthopedics Osteomyelitis Pathology Pharmaceutical Preparations Predisposition Prosthesis Prosthesis-Related Infections Rattus Replacement Arthroplasty Safety Saline Second Look Surgery Serum Staphylococcus aureus Staphylococcus aureus infection Surface Surgical Models System Systemic infection Technology Testing Thick Torsion Vancomycin aspirate bioluminescence imaging bone clinical translation clinically relevant comparative efficacy cortical bone drug resistance development efficacy evaluation ethylene glycol implant associated infection implant coating improved in vivo in vivo evaluation infection rate metallicity microbial nuclease operation phosphodiester phosphorothioate prevent prophylactic recurrent infection side effect standard care success surface coating translational potential

项目摘要

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.

项目摘要/摘要周围感染是骨科手术中最严重的并发症之一，发生在1-4％主要的总关节置换和最多30％的修订。由金黄色葡萄球菌引起的感染（S. 金黄色葡萄球菌）是骨科感染中最普遍的微生物罪魁祸首在植入物和臭名昭著的能力上形成生物膜的趋势侵入周围的管道网络骨。现有的预防性抗生素递送涉及不安全但无效的高药剂量可能导致耐药性的发展。利用寡核苷酸连接器使金黄色葡萄球菌不稳定微局局核酸酶（MN）裂解，我们最近开发了一种能够按需释放的水凝胶共价束缚的万古霉素。将作为水凝胶涂层应用于TI6AL4V肠内（IM）引脚插入与金黄色葡萄球菌接种的小鼠股管，Mn触发的万古霉素及时释放在植入物表面和IM空间内杀死了细菌，然后才有机会殖民或入侵围绕骨骼，从而防止生物膜形成和骨髓炎在3周内检查。在这种涂层中，万古霉素的共价绑扎剂量比典型的预防性抗生素含量在临床上使用。拟议的研究的目的是进一步设计令人兴奋的按需药物释放系统，以增强其血清稳定性并严格检查其在使用两种临床相关植入物感染提供持续保护对周期感染感染的持续保护型号。在AIM 1中，通过选择性2'-O-甲基化和维持磷酸胸酯的修饰，以达到增强的哺乳动物血清核酸酶稳定性对MN裂解的必要敏感性。在AIM 2中，将在体外优化的核苷酸连接器中实施 Mn敏感的水凝胶涂料并应用于Ti6Al4V IM引脚，以按需递送万古霉素。这这种预防性涂层的功效和安全性在提供及时和持续的保护链球菌方面使用大鼠股管感染模型，将在6个月内严格评估周围感染。在 AIM 3，这种按需抗生素释放策略在降低高体型感染中的效率将使用大鼠IM检查先前感染的大鼠股管的手术调试后的速率植入物修订手术模型。感染程度是销涂层和生物发光的函数。金黄色葡萄球接种通过生物发光成像和µCT定量纵向监测在2周，1、2、3和6个月时骨增厚 1、3和6个月的股骨外植物和股骨组织学的扭转测试。涂层的长期安全通过全身器官病理在终点进行检查。剂量的万古霉素的全身注射在感染动物的子集中进行了比预防涂层中的几百倍接收未涂层的IM引脚，以直接比较该预防性涂层的效率与标准护理。对周期感染或经常性感染实现更持续的保护比系统性万古霉素注射将被认为是成功的，同时实现了6的扩展保护没有局部和全身副作用的几个月将被认为是例外。如果成功验证，通过MN触发的万古霉素释放允许的细菌及时持续消除可能会汇集通过解决骨科植入物相关感染的艰巨挑战的安全性和效率绕过臭名昭著的难以治疗的生物膜和骨髓炎。