肿瘤光动力治疗中乏氧问题解决策略的研究进展

光动力疗法（photodynamic therapy, PDT）作为肿瘤治疗的一种新兴手段,已广泛应用于临床多种肿瘤的治疗。然而,PDT对氧气的依赖及肿瘤的乏氧环境严重限制了其治疗肿瘤的效果。近年来,解决PDT治疗肿瘤过程中的乏氧问题,提高其治疗效果已成为PDT领域的研究热点之一。本文从提高肿瘤组织的氧供给、肿瘤组织原位产氧、减少肿瘤耗氧、非氧气依赖的PDT等方面对肿瘤乏氧环境下增强PDT疗效的各种策略进行综合评述,为最终解决PDT治疗肿瘤过程中的乏氧问题提供参考。     

光动力治疗三要素及肿瘤光动力治疗后复发问题的探索

光动力疗法(photodynamic therapy,PDT)是一种联合利用光敏剂、光和氧,通过光动力反应选择性地治疗肿瘤的局部靶向疗法。光敏剂、激光和氧是光动力疗法的三个重要元素,本文主要从PDT的三要素及PDT后肿瘤复发进展的原因进行了综述。     

光动力疗法的协同治疗新策略

正光动力疗法(Photodynamic Therapy,PDT)是一种联合利用光敏剂、光和氧分子,通过光动力反应产生生物毒性物质单线态氧并选择性地治疗恶性肿瘤和良性病变,以及抗微生物(含细菌、病毒和感染等)的精准靶向疗法。随着PDT临床应用的推广,近年来相继发展了以提高或增强PDT疗效为目标的协同治疗新策略。除了基于开发并利用功能型光     

光敏剂分子信标的研究与应用进展

光动力疗法(Photodynamic Therapy,PDT)是一种联合利用光、光敏剂和氧分子,通过光动力反应选择性地治疗疾病的靶向疗法。光敏剂作为PDT的关键要素之一,其性能直接决定着PDT的疗效。笔者首先介绍了应用于PDT的光敏剂分子信标(photosensitizer molecular beacons,PMB)的基本原理,重点分析和总结了PMB中特异性肽链、淬灭基团和光敏剂等组分的研究进展。最后展望了PMB的发展趋势和潜在应用前景。     

肿瘤光动力疗法：理论基础及治疗策略

肿瘤的传统治疗方案主要包括手术治疗、放疗及化疗等,而光动力疗法（Photodynamic therapy,PDT）是肿瘤治疗领域内一项新的、引人注目的方法。它的基本过程是利用特定波长的光照射选择性蓄积在病变处的光敏剂,光敏剂随之活化并与氧分子作用产生具有细胞毒性的单线态氧及活性氧物质,经过直接与间接作用最终导致肿瘤细胞死亡。光动力疗法治疗肿瘤副作用小,对实体肿瘤尤其是浅表性肿瘤,如皮肤基底细胞癌等有着良好的治疗效果。光敏剂、光及组织氧是现代光动力疗法概念的重要组成部分。本文回顾并综述了光动力疗法的理论基础及治疗策略。     

单线态氧在光动力治疗中的作用机制及检测方法

光动力疗法(photodynamic therapy,PDT)已被广泛应用于治疗多种疾病,在光动力治疗过程中可产生大量活性氧自由基,其中单线态氧(singlet oxygen,~1O_2)被认为是光动力效应中的关键因子。~1O_2主要通过电子转移介导的氧化损伤对肿瘤细胞发挥作用,~1O_2的检测方法包括直接检测法和间接检测法(电子自旋共振法,分光光度计法等),明确~1O_2的作用机制及检测方法有助于进一步拓展PDT的适用范围和应用领域。本文就PDT中单线态氧的产生机制、作用机制及检测方法进行综述,为~1O_2的深入研究及PDT的临床应用提供依据。     

点阵铒激光联合5-氨基酮戊酸光动力疗法治疗痤疮瘢痕的可行性分析

光动力疗法（photodynamic therapy,PDT）与诊断（photodynamic dignosis,PDD）是一门新兴的发展中学科。是应用光敏剂和激光的药——械联合疗法,在生物组织中氧分子的参与下,通过光化学反应产生细胞毒性物质（如单线态氧）选择性破坏病变组织的无创治疗新技术。     

光子技术在光动力疗法剂量监测中的应用

光动力疗法（Photodynamic Therapy,PDT）是一种联合利用光敏剂、光和氧分子,通过光动力反应选择性地治疗恶性病变和良性病变等疾病的微创疗法。PDT作为国际前沿交叉学科“医学光子技术”的一个重要领域,近年来随着各种实时、无损和高灵敏度光学检测与成像技术的出现,     

光动力疗法治疗银屑病的研究进展

光动力疗法（photodynamic therapy,PDT）是建立在光敏剂基础上的治疗方法。当用特定波长的光照射,产生大量的活性氧物质,从而造成细胞的损伤和死亡,以达到治疗目的。早期PDT在皮肤科主要用于肿瘤的治疗并取得疗效,新近研究者应用PDT治疗银屑病,也取得一定疗效。然而尚需大量的比较性研究以及PDT治疗方案的优化以确定PDT在银屑病治疗中的地位。     

低光参量肿瘤靶向光动力疗法的免疫效应及其机制

光动力疗法(photodynamic therapy, PDT)是治疗恶性肿瘤的一种有效手段,除了直接杀伤肿瘤细胞、破坏肿瘤血管外,它还可以诱导机体抗肿瘤免疫。增强PDT诱导的抗肿瘤免疫效应对于防止肿瘤复发、控制已转移肿瘤生长有着重要意义,也是近年来肿瘤靶向PDT的研究热点。肿瘤靶向PDT诱导的免疫效应的强弱与各种参数密切相关,如光功率密度、能量密度、光敏剂种类和剂量等。研究表明,低光参量PDT与常规光参量PDT相比可以诱导更强的抗肿瘤免疫效应,有望提高肿瘤靶向PDT的长期疗效。本文对PDT抗肿瘤免疫和低光参量PDT诱导的免疫效应及其机制做一总结,为进一步优化肿瘤靶向PDT治疗方案以提高其抗肿瘤免疫效应和长期疗效提供参考。     

Mechanisms in photodynamic therapy: part one—photosensitizers, photochemistry and cellular localization

The use of non-toxic dyes or photosensitizers (PS) in combination with harmless visible light that is known as photodynamic therapy (PDT) has been known for over a hundred years, but is only now becoming widely used. Originally developed as a tumor therapy, some of its most successful applications are for non-malignant disease. In a series of three reviews we will discuss the mechanisms that operate in the field of PDT. Part one discusses the recent explosion in discovery and chemical synthesis of new PS. Some guidelines on how to choose an ideal PS for a particular application are presented. The photochemistry and photophysics of PS and the two pathways known as Type I (radicals and reactive oxygen species) and Type II (singlet oxygen) photochemical processes are discussed. To carry out PDT effectively in vivo, it is necessary to ensure sufficient light reaches all the diseased tissue. This involves understanding how light travels within various tissues and the relative effects of absorption and scattering. The fact that most of the PS are also fluorescent allows various optical imaging and monitoring strategies to be combined with PDT. The most important factor governing the outcome of PDT is how the PS interacts with cells in the target tissue or tumor, and the key aspect of this interaction is the subcellular localization of the PS. Examples of PS that localize in mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus and plasma membranes are given. Finally the use of 5-aminolevulinic acid as a natural precursor of the heme biosynthetic pathway, stimulates accumulation of the PS protoporphyrin IX is described.     

Pulse mode of laser photodynamic treatment induced cell apoptosis

One of the factors limiting photodynamic therapy (PDT) is hypoxia in tumor cells during photodynamic action. PDT with pulse mode irradiation and appropriate irradiation parameters could be more effective in the singlet oxygen generation and tissue re-oxygenation than continuous wave (CW) mode. We theoretically demonstrate differences between the cumulative singlet oxygen concentration in PDT using pulse mode and CW mode of laser irradiation. In vitro experimental results show that photodynamic treatment with pulse mode irradiation has similar cytotoxicity to CW mode and induces mainly cell apoptosis, whereas CW mode induces necrotic cell death. We assume that the cumulative singlet oxygen concentration and the temporal distribution of singlet oxygen are important in photodynamic cytotoxicity and apoptosis initiation. We expect our research may improve irradiation protocols and photodynamic therapy efficiency.     

光动力治疗与细胞自噬的研究进展

细胞自噬是真核生物中一种发现不久的普遍存在的生理现象,是涉及细胞自我消化的一系列生化过程。光动力治疗（photodynamic therapy,PDT）中,选择性聚集在快速增殖细胞（如肿瘤细胞）中的光敏剂分子经一定波长激光照射,产生有细胞毒作用的单态氧或氧自由基,靶向性地杀伤肿瘤细胞,引起肿瘤细胞死亡。PDT作用过程能够诱发一些细胞器如内质网、线粒体、细胞膜和溶酶体的损害,进而引起细胞凋亡和自噬的发生。对于一些接受低水平剂量的光动力作用细胞,其发生的自噬被认为与提高细胞在应激环境下的生存有着密切联系。然而,当凋亡受到抑制或是自噬水平无限制的持续上调时,自噬就成为了细胞死亡的一种途径。目前很多相关的实验技术已运用来检测细胞自噬的特征,本文就针对光动力治疗后引起自噬的一些相关问题做一详细综述。     

Photodynamic therapy for prostate cancer: One urologist's perspective

Photodynamic therapy (PDT) has slowly found its place in the treatment of human disease. Currently, photodynamic therapy is being explored as a treatment option for localized prostate cancer. PDT for the treatment of prostate cancer will require ablation of both malignant and non-malignant glandular epithelium. Ablation of both malignant and normal epithelium adds a new treatment dimension since traditionally PDT has not targeted normal epithelial tissue. PDT for prostate cancer as currently envisioned will present challenges in terms of in situ monitoring of light, drug concentration, p_O2 levels and biologic endpoints. The introduction of vascular-targeted photosensitizers fundamentally alters the traditional axioms for successful PDT treatment by obviating the need for “selective” tumor localization. Should clinical trials demonstrate the utility of this approach, patients with organ-confined disease will benefit.     

CuS nanoagents for photodynamic and photothermal therapies: Phenomena and possible mechanisms

Photodynamic therapy (PDT) and photothermal therapy (PTT) have been emerging as attractive and promising methods for tumor treatment in clinical approaches. CuS nanoparticles are effective and cost-effective agents for PTT. Recently, it was observed that CuS nanoparticles are also excellence candidates for PDT. However, the mechanisms for CuS nanoparticles as PDT agents have never been discussed. The goal here is to explore the killing mechanisms of CuS nanoparticles as PTT and PDT agents. CuS nanoparticles were synthesized by a simple wet chemistry method by coating with amphiphilic polymer and examined for their therapeutic potential on lung adenocarcinoma cell line SPC-A-1 in vitro and in vivo using a murine cancer model. The CuS nanoparticles produce heat as well as reactive oxygen species (ROS) when excited by 808 nm laser and show strong anticancer effects both in vitro and in vivo. The heating effects and release of copper ions from CuS upon heating in the tumor acidic environments are the main mechanisms for the generation of reactive oxygen species which are lethal bullets for cancer destruction. As a dual-function agent for PTT and PDT, CuS nanoparticles are promising phototherapy agents for cancer treatment.     

Optical coherence tomography imaging of non-melanoma skin cancer undergoing photodynamic therapy reveals subclinical residual lesions

BackgroundPhotodynamic therapy with methyl aminolaevulinate (MAL–PDT) is a widely used non-invasive treatment modality for non-melanoma skin cancer (NMSC). The outcome of MAL–PDT is usually primarily evaluated clinically. Optical coherence tomography (OCT) is a non-invasive imaging technology based on interferiometry. OCT has been proven to provide high accuracy in identifying NMSC lesions and performing thickness measurements of thin tumours.ObjectivesTo describe the OCT morphology in in-vivo NMSC lesions during MAL–PDT treatment and to investigate the use of OCT in evaluating the response of MAL–PDT treated NMSC lesions.MethodsA total of 18 biopsy-proven basal cell carcinomas and actinic keratoses were monitored by OCT during 2 sessions of MAL–PDT treatment. At 3-months follow-up the patients were assessed both by OCT and clinically. If the clinical and OCT evaluation came to different conclusions on recurrence of the lesion, patients were followed more closely at clinical appointments for up to one year after the PDT treatment.ResultsAll lesions displayed at least one OCT characteristic before MAL–PDT treatment. At 3 months follow-up, recurrence was suspected clinically in 5/18 cases, with OCT in 7/18 cases. OCT correctly identified all of the partial responses also found by the clinical examinations. In both cases where recurrence was only found in OCT, this was subsequently confirmed by histology.ConclusionsOur study suggests that OCT identified 29% more recurrences than clinical examination alone. OCT can detect subclinical residual NMSC lesions after MAL–PDT treatment and may therefore be an accurate tool for early detection of residual lesional tissue.     

不可切除胆管癌PDT治疗的进展

胆管癌是一种少见的原发性胆道恶性肿瘤,预后较差,根治性切除仅适用于少部份早期确诊的患者,大部份失去手术机会的患者采取胆道引流的姑息治疗方式治疗。胆道缓解引流是一种采用经皮或内镜插入的内镜置管术,可减轻患者骚痒、胆管炎和疼痛等症状,提高患者生活质量,但是仅有少量文献报道胆道缓解引流可提高胆管癌患者的生存时间。光动力疗法（photodynamic therapy,PDT）是一种相对新的、局部的、微创的姑息治疗方法,PDT是通过能聚集在增生组织（或肿瘤）中的光敏剂分子,是治疗不可手术切除胆管癌的标准的辅助治疗方式。     

The history of PDT in Norway: Part one: Identification of basic mechanisms of general PDT

Photodynamic therapy (PDT) is now an established treatment of malignant and premalignant dysplasias. A number of first and second generation photosensitizers have been studied in Norway. The aim has been to improve PDT efficiency and applicability. Many critical details regarding the mechanisms of PDT were elucidated by researchers in Norway. In this review we focus on the most important findings related to these basic mechanisms, such as generation of singlet oxygen, estimations of its lifetime, the oxygen effect itself, the subcellular localization of photosensitizers with different properties, their photodegradation during PDT and their tumour selectivity.