Nanotherapeutics for Ocular Infections

 描述(申请人提供)：眼部细菌感染导致全球相当数量的失明病例。防止在感染期间对脆弱的眼睛组织造成损害的努力有赖于迅速和适当地使用治疗药物，以迅速杀死微生物并遏制潜在的破坏性炎症。目前使用的抗生素可以杀死微生物，但抗炎药的有效性存在争议。这些药物类别不针对由细菌在感染部位合成的破坏组织的毒素。金黄色葡萄球菌、肺炎链球菌、蜡状芽孢杆菌和粪肠球菌等革兰氏阳性眼部致病菌对眼部致病作用非常重要，而且常常是必不可少的。当没有PFTs时，眼部毒力显著降低。新的PFT靶向疗法能够中和跨物种的毒素，将覆盖导致眼表(角膜炎)和眼内(眼内炎)感染的最常见的革兰氏阳性病原体。毒素中和作为抗生素和消炎剂的辅助手段，将大大改善目前对组织破坏性毒素无效的治疗方法。最近已经开发出针对革兰氏阳性PFTs的纳米棒。在体外，纳米粒子中和了革兰氏阳性的PFT。在脓毒症和组织感染的体内实验模型中，纳米颗粒中和感染部位的毒素，降低毒力。我们推测，纳米颗粒可以有效地降低眼环境中细菌PFTs的毒性活性，从而与抗生素一起作为一种新型的抗毒素疗法用于治疗眼内和眼表感染。初步数据证明了检验我们假设的可行性。我们发现，纳米颗粒1)中和革兰氏阳性眼部病原体的PFT，2)在泪液、玻璃体和抗生素存在的情况下这样做，3)防止有毒的眼细胞死亡，4)对小鼠眼睛无毒。眼部细菌感染的临床改善的一个关键障碍是缺乏毒素靶向。我们将测试纳米颗粒对引起角膜炎(目标1)和眼内炎(目标2)的眼部病原体的PFT中和活性和抗生素的有效性，并将调查它们在眼部应用后的生物分布(目标3)。如果纳米粒子有效，下一步就是用更有效的抗生素和更好的抗炎药来测试纳米粒子。测试纳米颗粒在治疗眼部细菌感染中的风险很高，但它是新的、高影响的、翻译相关的，并将通过确定一种新的抗毒素疗法来积极影响眼部感染疾病领域，该疗法可能在感染期间保护眼部脆弱组织。拟议的研究是我们的眼部感染研究计划合乎逻辑的产物，我们处于有利地位，能够提供有价值的信息，为医生提供尽可能好的治疗方案，以在眼部感染期间保护视力。

 DESCRIPTION (provided by applicant): Ocular bacterial infections cause a significant number of cases of blindness worldwide. Efforts to prevent damage to delicate ocular tissues during infection rely on swift and proper use of therapeutics to rapidly kill organisms and arrest potentially damaging inflammation. Currently-used antibiotics can kill organisms, but the effectiveness of anti-inflammatory drugs is controversial. These drug classes do not target tissue-damaging toxins synthesized by bacteria at the site of infection. Pore-forming toxins (PFTs) are important, and often essential, to ocular virulence of the following Gram-positive ocular pathogens: Staphylococcus aureus, Streptococcus pneumoniae, Bacillus cereus, and Enterococcus faecalis. When PFTs are absent, ocular virulence is significantly decreased. Novel PFT-targeting therapeutics which neutralize toxins across species would provide coverage for the most common Gram-positive pathogens causing ocular surface (keratitis) and intraocular (endophthalmitis) infections. Toxin neutralization as an adjunct with antibiotics and anti-inflammatory agents would provide a significant improvement over current therapies that are ineffective against tissue-damaging toxins. Nanosponges have recently been developed which target Gram-positive PFTs. In vitro, nanosponges neutralize Gram-positive PFTs. In in vivo experimental models of sepsis and tissue infection, nanosponges neutralize toxins at the site of infection and reduce virulence. We hypothesize that nanosponges can effectively reduce the toxic activity of bacterial PFTs in the ocular environment, leading to use as a novel anti-toxi therapeutic with antibiotics for the treatment of intraocular and ocular surface infections. Preliminary data demonstrates the feasibility of testing our hypothesis. We show that nanosponges 1) neutralize PFTs of Gram-positive ocular pathogens, 2) do so in the presence of tears, vitreous, and antibiotics, 3) protect against toxic ocular cell death, and 4) are not toxic in/on mouse eyes. A critical barrier to clinical improvements in ocular bacterial infections is th absence of toxin- targeting. We will test nanosponges for PFT-neutralizing activity and efficacy with antibiotics against ocular pathogens causing keratitis (Aim 1) and endophthalmitis (Aim 2), and will also investigate their biodistribution following ocular application (Aim 3). If nanosponge are effective, the next step is to test nanosponges with more potent antibiotics and better anti-inflammatory agents. Testing of nanosponges in the treatment of ocular bacterial infections is high risk, but is novel, high-impact, translationally relevant, and will positively influence the ocular infectious disease field by identifying a novel anti-toxin therapy which may protect delicate tissues of the eye during infection. The proposed studies are a logical outgrowth of our ocular infection research program, and we are well positioned to contribute valuable information which will provide physicians with the best possible therapeutic options to preserve vision during ocular infections.