SIGNIFICANCE OF CORNEAL CELL INVASION BY BACTERIA

细菌入侵角膜细胞的意义

• 批准号: 2165529
• 负责人: Suzanne MJ FLEISZIG
• 金额: $ 14.22万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-07-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2165529
• 关键词: SIGNIFICANCE; CORNEAL; CELL; INVASION; BACTERIA

DESCRIPTION: (from the abstract) The broad long term goal of this research is to understand the role of corneal cell invasion by bacteria in the pathogenesis of bacterial infectious keratitis due to Pseudomonas aeruginosa, and to develop strategies for treatment and/or prevention of this disease. Since P. aeruginosa is believed to be an extracellular pathogen, research into the pathogenesis of this disease has focused on bacterial adherence to the cornea, bacterial toxins, and the host inflammatory response. It has now been demonstrated that P. aeruginosa can invade corneal cells; during corneal infection and in various in vitro models. Intracellular bacteria can evade host defenses and some antibiotics, and could thus explain why P. aeruginosa keratitis is often persistent and difficult to treat. The first aim of this proposal is to test whether corneal cell invasion by P. aeruginosa contributes to the development of infectious keratitis. The proposed methods involve identification of means to inhibit P. aeruginosa invasion of corneal cells, and then use of these methods to inhibit invasion whilst monitoring the effect on development of disease. P. aeruginosa cannot infect an intact healthy cornea and infection is most commonly associated with either corneal injury or contact lens wear. Thus, two different experimental models for studying P. aeruginosa corneal infection will be utilized; a murine model involving abrasion injury to the cornea, and a rabbit model for contact lens overwear. Levels of bacterial invasion into cells will be determined by gentamicin survival assays, and the severity of disease assessed by macroscopic examination of the cornea. Contact lens wear is the leading cause of P. aeruginosa corneal infection in humans. The second hypothesis to be tested is that following the introduction of P. aeruginosa into the eye, contact lens wear eventually increases the total number of intracellular bacteria on the cornea in comparison to eyes that do not wear lenses, by one or more of three mechanisms. These are: 1) that environmental conditions occurring under a contact lens which alter the metabolic function of corneal cells also alter the susceptibility of these cells to P. aeruginosa invasion; 2) that contact lens wear increases P. aeruginosa invasion of cells secondarily to increased bacterial adherence to these cells; and 3) that contact lens wear impedes the clearance of intracellular P. aeruginosa from the ocular surface by interfering with superficial epithelial cell exfoliation and/or by stagnation of cells under the contact lens. This hypothesis will be tested by: 1) examining the effect of environmental manipulations on P. aeruginosa entry into cultured corneal epithelial cells and whole mouse cornea in vitro; 2) comparing P. aeruginosa invasion into superficial corneal epithelial cells removed from human contact lens wearing and control subjects; and 3) evaluating whether intracellular bacteria are stagnated in the rabbit eye during contact lens wear. Infectious keratitis is the most serious complication of contact lens wear. Since contact lenses are most frequently worn in healthy eyes, even a low incidence of this serious disease is unacceptable. Factors that make certain patients more susceptible to infection and new approaches for the prevention and/or treatment of infection could be identified by the proposed studies.

描述：（从摘要中）这个广泛的长期目标 研究是了解细菌角膜细胞侵袭的作用 在通过假单胞菌引起的细菌感染性角膜炎的发病机理 铜绿，并制定治疗和/或预防的策略 这种疾病。 由于铜绿假单胞菌被认为是细胞外 病原体，对这种疾病发病机理的研究集中在 细菌遵守角膜，细菌毒素和宿主 炎症反应。 现在已经证明了铜绿假单胞菌 可以入侵角膜细胞；在角膜感染期间和各种 体外模型。 细胞内细菌可以逃避宿主防御和一些 抗生素，因此可以解释为什么铜绿假单胞菌角膜炎通常是 持续且难以治疗。 该提议的第一个目的是 测试铜绿假单胞菌的角膜细胞是否有助于 传染性角膜炎的发展。 提出的方法涉及 识别抑制铜绿假单胞菌入侵角膜的手段 细胞，然后使用这些方法来抑制入侵 监测对疾病发展的影响。 P.铜绿不能 感染完整的健康角膜和感染是最常见的 与角膜损伤或隐形眼镜磨损有关。 因此，两个 研究铜绿假单胞菌角膜的不同实验模型 感染将被利用；涉及磨损损伤的鼠模型 角膜和隐形眼镜的兔模型。 水平 细菌侵袭将通过庆大霉素的存活确定 测定和通过宏观检查评估的疾病严重程度 角膜。 隐形眼镜磨损是铜绿假单胞菌的主要原因 人类的角膜感染。 要测试的第二个假设是 将铜绿假单胞菌引入眼睛后，隐形眼镜 磨损最终会增加细胞内细菌的总数 与不佩戴镜头的眼睛相比，角膜是一个或多个 三种机制。 这些是：1）环境条件 发生在改变的隐形眼镜下，改变了 角膜细胞还改变了这些细胞对P的敏感性。 铜绿侵袭； 2）隐形眼镜的磨损增加了铜绿假单胞菌 细胞的侵袭第二，以增加细菌的依从性 细胞； 3）隐形眼镜戴上阻碍的清除 通过干扰眼表的细胞内铜绿假单胞菌 浅表上皮细胞去角质和/或通过停滞 在隐形眼镜下。 该假设将通过：1）检验 检查环境操纵对铜绿假单胞菌的影响 进入培养的角膜上皮细胞和整个小鼠角膜 体外2）将铜绿假单胞菌侵袭与表层角膜 从人类隐形眼镜佩戴和控制中去除的上皮细胞 受试者； 3）评估细胞内细菌是否被停滞 在隐形眼镜磨损期间，在兔子眼中。 感染性角膜炎是 隐形眼镜磨损的最严重并发症。 由于隐形眼镜是 最经常穿着健康的眼睛，即使是这样的发病率很低 严重疾病是不可接受的。 使某些患者更多的因素 容易感染和预防新方法和/或 拟议的研究可以鉴定感染的治疗。