Photodynamic Therapy of Localized Infections

局部感染的光动力疗法

基本信息

批准号：
8814160
负责人：
MICHAEL R HAMBLIN
金额：
$ 42.91万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-07-01 至 2016-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8814160
关键词：
Abscess Address Animals Anions Antibiotic Resistance Antibiotics Antifungal Agents Area Aspergillus Azides Bacteria Biological Burn injury Candida albicans Cell Death Cells Cessation of life Charge Chemosensitization Chronic Sinusitis Clinical Trials Data Decontamination Dental Development Disease Drug Delivery Systems Effectiveness Electricity Electron Transport Electroporation Endodontics Fiber Firefly Luciferases Focal Infection Fullerenes Funding Future Genetic Engineering Grant Health Helicobacter Infections Human Hydroxyl Radical Image Imaging Techniques In Vitro Inbred HRS Mice Infection Investigation Iodides Ions Iontophoresis Knowledge Lasers Leg Ulcer Letters Life Light Lipids Luciferases Mammalian Cell Mediating Methods Methylene blue Microbe Modeling Molecular Motivation Mus Mycoses Nose Nucleic Acids Operative Surgical Procedures Orthopedics Oxygen PUVA Photochemotherapy Patients Penetration Periodontitis Pharmaceutical Preparations Photosensitizing Agents Pneumonia Prevention Prosthesis Proteins Pseudomonas Reactive Oxygen Species Regimen Research Research Project Grants Resistance development Role Salts Sepsis Sinusitis Skin Solutions Stomach Therapeutic Time Tissues Tobramycin Tonsillitis Topical application Virus Visible Radiation Work Wound Infection antimicrobial bioluminescence imaging clinical practice design fungus in vivo interest killings methicillin resistant Staphylococcus aureus microbial mouse model novel oxidation prevent resistant strain response

项目摘要

DESCRIPTION (provided by applicant): The overall objective of this revised second competitive renewal is to continue our investigations on the role of photodynamic therapy (PDT) in treating localized infections. PDT employs non-toxic photosensitizers (PS) and harmless visible light (frequently red light for increased tissue penetration) that combine in the presence f oxygen to produce reactive oxygen species that damage biological molecules such as proteins, lipids and nucleic acids and subsequently cause cell death. In the two funding periods of this grant we have synthesized and characterized several novel highly active antimicrobial PS and demonstrated their effectiveness in treating mouse models of infected wounds, burns and abscesses. In some cases PDT can save mice from a certain death due to sepsis that develops from an untreated localized infection. A combination of the appropriate molecular design of the PS, together with topical or local application of the PS to the infected area and a short drug-ligh interval allows high selectivity for microbial cells compared to the surrounding host cells. The broad motivation for this line of research is the relentless worldwide increase in antibiotic resistance amongst pathogenic microbes, and it has been found that multi-antibiotic resistant strains are in general as sensitive to photodynamic inactivation (PDI) as naïve strains, and moreover that microbial cells are unable to develop resistance to PDI. Aim 1 will explore a finding that the clinically approved PS, methylene blue and related penothiazinium salts could have their antimicrobial PDT effect potentiated by addition of simple ions like iodide. While we initially interpreted this to involve electron transfer (oxidation) from hydroxyl radicals, we have now discovered that we can still get killing in the absence of oxygen. In addition to studying the contribution of Type 1 and Type 2 photochemical mechanisms we are now investigating a possible mechanism involving direct oxidation of iodide (and azide) anions by excited state MB to produce iodide/azide radicals that efficiently kill microbial cells. Aim 2 proposes a solution t the biggest barrier to the effectiveness of antimicrobial PDT in vivo i. e. delivering the photosensitizer (PS) into the infected tissue. Since all highly effective antimicrobial PS have cationic charges they are ideally suited for delivery into tissue by electricity. We will explore te use of iontophoresis and electroporation singly and in combination to deliver antimicrobial PS (and iodide) into ex vivo pigskin and into hairless mouse skin. Aim 3 responds to the reviewers' criticisms by exploring the combination of PDT with traditional systemic antibiotics to prevent regrowth of bacteria after PDT. Preliminary data has shown that a sub-therapeutic regimen of tobramycin can synergistically combine with a PDT regimen mediated by a fullerene and white light to save mice from dying in a Pseudomonas wound infection model. We will study possible synergy in vitro using MIC determinations with PDT and/or antibiotics In aim 4 in response to the reviewers' criticisms we will study selectivity for killing microbial cells (both fungi and bacteria) over mammalian skin cells (both mouse and human) and look at possible damage in tissue removed from mice. We have found some highly effective antifungal PS and will study these in vitro and in vivo with emphasis on selectivity. We now have access to Candida albicans that has been genetically engineered to express Gaussia princeps luciferase and Aspergillus fumigates expressing firefly luciferase that form localized infections that can be imaged by bioluminescence imaging.

描述（由申请人提供）：本次修订后的第二次竞争性更新的总体目标是继续研究光动力疗法 (PDT) 在治疗局部感染中的作用。PDT 采用无毒光敏剂 (PS) 和无害的可见光（通常为光动力疗法）。红光增加组织渗透），在氧气存在的情况下结合产生活性氧，破坏蛋白质、脂质和核酸等生物分子，并随后导致细胞死亡。并表征了几种新型高活性抗菌 PS，并证明了它们在治疗感染伤口、烧伤和脓肿的小鼠模型中的有效性。在某些情况下，PDT 可以挽救小鼠免于因未经治疗的局部感染而导致的脓毒症死亡。与周围宿主细胞相比，PS 与局部或局部应用 PS 以及较短的药物间隔时间使得微生物细胞具有高选择性。这一系列研究的广泛动机是全世界范围内的不懈努力。病原微生物中的抗生素耐药性增加，并且已发现多重抗生素耐药菌株通常与初始菌株一样对光动力失活（PDI）敏感，而且微生物细胞无法对 Aim 1 产生耐药性。探索了一项发现，即临床批准的 PS、亚甲蓝和相关的哌噻嗪盐可以通过添加碘化物等简单离子来增强其抗菌 PDT 效果，而我们最初对此进行了解释。为了涉及羟基自由基的电子转移（氧化），我们有现在发现，在没有氧气的情况下，我们仍然可以杀死人。除了研究 1 型和 2 型光化学机制的贡献外，我们现在正在研究一种可能的机制，涉及激发态 MB 直接氧化碘化物（和叠氮化物）阴离子。目标 2 提出了一种解决体内抗菌 PDT 有效性的最大障碍，即传递光敏剂 (PS)。由于所有高效的抗菌 PS 都具有阳离子电荷，因此它们非常适合通过电传递到组织中，我们将探索单独或组合使用离子电渗疗法和电穿孔将抗菌 PS（和碘化物）传递到离体猪皮中。目标 3 通过探索 PDT 与传统全身抗生素的结合以防止 PDT 后细菌的再生来回应审稿人的批评。已经表明，妥布霉素的亚治疗方案可以与富勒烯和白光介导的 PDT 方案协同作用，以挽救假单胞菌伤口感染模型中的小鼠死亡。我们将使用 PDT 和/或 MIC 测定来研究体外可能的协同作用。抗生素在目标 4 中，为了回应审稿人的批评，我们将研究杀死微生物细胞（真菌和细菌）相对于哺乳动物皮肤细胞（小鼠和细菌）的选择性。我们已经发现了一些高效的抗真菌PS，并将在体外和体内研究它们，重点是选择性。我们现在可以获得经过基因工程改造以表达Gaussia的白色念珠菌。表达萤火虫荧光素酶的王子荧光素酶和熏曲霉形成局部感染，可以通过生物发光成像进行成像。