Photodynamic Therapy of Localized Infections

局部感染的光动力疗法

基本信息

批准号：
8438839
负责人：
MICHAEL R HAMBLIN
金额：
$ 40.12万
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 2018-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8438839
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 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 Patients Penetration Periodontitis Pharmaceutical Preparations Photochemotherapy 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 public health relevance 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 na¿ve 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（由适用提供）：该修订后的第二次竞争更新的总体目标是继续我们对光动力疗法（PDT）在治疗局部感染中的作用的研究。 PDT员工无毒的光传感器（PS）和无害的可见光（通常是红光，用于增加组织穿透力），这些光在存在的存在F氧气中产生活性氧，从而损害了生物学分子，例如蛋白质，脂质和核酸，随后导致细胞死亡。在这笔赠款的两个资金期间，我们综合并表征了几种新型高度活跃的抗菌PS，并证明了它们在治疗感染伤口，灼伤和脓肿的小鼠模型中的有效性。在某些情况下，PDT可以使小鼠免于因未经处理的局部感染而发展而导致的败血症。与周围宿主细胞相比，PS的合适分子设计以及PS在感染区域的局部或局部应用以及短期药物间隔的局部或局部应用的组合可以使微生物细胞的高选择性。这项研究线的广泛动机是致病性微生物中抗生素抗性的不断增加，并且已经发现，多种抗生素的抗菌株通常对光动力失活（PDI）敏感，因为NA¿VE毒性菌株，并且微生物细胞无法对PDI产生抵抗力。 AIM 1将探索一个发现，即经过临床批准的PS，亚甲基蓝和相关的penothiazinium盐可以通过添加碘化物（如碘化物）来产生其抗菌PDT效应。尽管我们最初将其解释为涉及羟基自由基的电子转移（氧化），但我们已经现在发现，在没有氧气的情况下，我们仍然可以杀死。除了研究1型和2型光化学机制的贡献外，我们现在还研究了一种可能的机制，涉及激发态MB直接氧化碘化物（和叠氮化物）阴离子，以产生有效杀死微生物细胞的碘化物/叠氮化物。 AIM 2提案A解决方案是抗菌PDT体内有效性的最大障碍。 e。将光敏剂（PS）传递到感染组织中。由于所有高效的抗微生物PS具有阳离子电荷，因此非常适合通过电力输送到组织中。我们将单独探索离子噬菌体和电穿孔的用途，并结合使用，以将抗菌PS（和碘化物）输送到离体猪皮中，并将其输入无毛小鼠皮肤中。 AIM 3通过探索PDT与传统的系统性抗生素的结合来应对审稿人的批评主义，以防止PDT后的细菌改革。初步数据表明，毒素的亚治疗方案可以合成与富勒烯和白光介导的PDT方案结合，以使小鼠免于在假单胞菌伤口伤口感染模型中死亡。我们将在AIM 4中使用PDT和/或抗生素的MIC测定，以响应审查者的批判主义，研究可能在杀死哺乳动物皮细胞（小鼠和人类）杀死微生物细胞（真菌和细菌）的选择性时，研究可能的协同体外协同作用。我们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。现在，我们可以使用一般设计的白色白色念珠菌，以表达高斯王子荧光素酶和曲霉烟熏酸盐，表达萤火虫荧光素酶，这些萤火虫可以通过生物发光成像来成像。