光动力治疗光源的研究新进展

光动力疗法(PDT)是一种联合利用治疗光源、光敏剂和氧分子,选择性治疗恶性肿瘤和良性疾病的精准靶向疗法。光源作为PDT治疗的关键要素之一,其发光波长、照光方式和剂量直接影响疗效。本文详细介绍了太阳光、近红外光、X射线、在体发光和发光二极管等5种PDT光源的研究新进展,并分析了这五种治疗光源在生物组织穿透深度上的不同特性以及所存在的不足。随后,重点讨论了以提高PDT治疗精度为目标的体表照光和体内照光等两种个性化照光模式。研发操作简便、价格低廉、性能优异的新型PDT光源是未来的发展方向。     

光动力疗法对肿瘤的作用机制及其影响因素

光动力疗法（photodynamic therapy,PDT）被提出可用于肿瘤治疗已有25年历史。最近几年,PDT在临床上得到了较广泛的应用。一些光敏剂已被某些国家批准作为PDT药物。有关新型光敏剂的合成、体内体外试验、作用机制等方面的研究得到了迅速的发展,并取得了丰硕的成果。现从光动力反应基本原理出发,回顾了有关肿瘤PDT作用机制特别是细胞水平作用机制及其影响因素的最新研究成果。对肿瘤PDT作用机制进行全面深入的探讨,将有助于寻找改善和加强PDT功效的方法,使其在肿瘤治疗中发挥更大的优势。     

具有自噬抑制作用的卟啉金属有机框架的制备及其光动力癌症治疗的研究*

光动力疗法(PDT)具有微创、可控、低毒、可重复治疗等优点,已成为临床医学中不可缺少的治疗手段。但由于肿瘤细胞的自我保护机制,大大降低了PDT疗效。使用PDT治疗方法的同时实施药理自噬抑制策略,切断因光动力治疗下严重氧化损伤下的保护性自噬。通过油浴加热法合成卟啉金属有机框架PCN-224,并在PCN-224上负载自噬抑制剂硫酸羟氯喹(HCQ),通过扫描电子显微镜(SEM)、粒径测试(DLS)、紫外可见光谱测试等方法检测,结果表明成功地合成了该材料,增强了卟啉光敏剂的水溶性,并且光照后对4T1小鼠乳腺癌细胞毒性明显增强,且装载了HCQ后进一步提高了肿瘤杀伤能力。     

光学成像技术在体研究肿瘤的光动力效应

光动力疗法 (PDT) 已发展成为一种较成熟的肿瘤治疗方法, PDT 诱导的血管损伤是杀死肿瘤的重要机制之一 . 为了在活体肿瘤模型上实时监测 PDT 导致的血管损伤效应,使用稳定高表达绿色荧光蛋白 (GFP) 的人涎腺腺样囊性癌细胞株 (ACC-M-GFP) ,建立了基于鸡胚尿囊膜 (CAM) 的肿瘤模型 . 应用荧光成像技术对肿瘤的生长位置、大小,以及治疗区域进行方便精确的定位;利用激光散斑成像技术,实时监测 CAM 上肿瘤周围血管的血液动力学参数 . 发现不同光动力剂量所导致的血管损伤有显著不同 . 结果表明,荧光标记的鸡胚尿囊膜肿瘤模型为研究 PDT 导致的血管损伤效应提供了良好的实验模型,激光散斑成像技术适用于实时监测 PDT 过程中血管结构、血流速度的变化,由此得出血液灌注率可用以评估 PDT 对肿瘤周围血管的损伤效应 .     

上转换纳米颗粒在肿瘤诊断与治疗中的研究进展

上转换纳米颗粒具备光学/化学稳定性高、生物毒性低、荧光寿命长及激发光生物组织穿透深度较大等显著优点,近年来在生物传感、生物成像和疾病治疗等生物医学领域的研究和应用获得了广泛的关注。本文中,笔者就稀土元素掺杂的上转换纳米颗粒在肿瘤的诊断与治疗方面的研究现状及进展进行综合概述,主要对其在光动力疗法(PDT)、光热疗法(PPT)、化学联合疗法及多模态诊疗一体化等方面的研究展开分析和讨论,为上转换纳米颗粒的进一步研究开发及临床应用提供新的参考方向及思路。     

光动力学疗法剂量学的研究进展

随着光动力学疗法 ( photodynamic therapy,PDT ) 基础研究的不断深入和临床应用的广泛开展,如何精确量化光动力剂量,并根据患者的个体差异进行剂量的实时调整和优化已成为亟待解决的挑战性难题,属PDT研究的前沿热点．综述了现有PDT剂量学研究方法及其相应检测技术的研究进展,其中包括：a．测定光通量密度、光敏剂浓度和氧分压;b．测量光敏剂的光漂白速率和光致产物;c．监测PDT前后组织的光生物学响应;d．检测单态氧在1 270 nm的近红外发光．同时,还分析了这些PDT剂量学方法的优点和局限性．最后,讨论了PDT剂量学研究中所面临的挑战．     

不同光敏剂孵育时间在白念珠菌光动力抑制效应中的实验研究

目的：通过测定5?氨基酮戊酸（5?ALA）与白念珠菌菌悬液不同孵育时间生成PpIX的水平及5?氨基酮戊酸光动力疗法（5?ALA?PDT）抑菌率,为临床选择最佳孵育时间提供理论依据。方法制备白念珠菌悬液并与ALA避光孵育,设实验组和对照组。采用激光共聚焦显微镜观察PpIX产生情况,MTT法测定ALA光动力治疗对白念珠菌生长的抑制率。结果白念珠菌菌悬液与ALA避光孵育后有荧光物质PpIX产生,孵育30 min到90 min产生的PpIX最多,120 min以后PpIX开始明显减少,对照组无荧光物质出现。结论 ALA?PDT对白念珠菌抑制效应同孵育时间密切相关。这为临床ALA?PDT治疗白念珠菌疾病提供了理论依据。     

光动力疗法对体外培养人胰腺癌细胞株PANC-1作用

目的:探讨血卟啉注射液(Hematoporphyrin Derivative,HPD)光动力疗法(Photodynamic Therapy,PDT)对体外培养的人胰腺癌细胞株PANC-1的生物作用。方法:实验分为4组,空白对照组、单纯HPD组、单纯光照组及HPD+PDT组。采用MTT法检测光动力作用后细胞的存活率,并用Annexin V-FITC/P I双染法检测其凋亡率。结果:在光敏剂浓度为5mg/L,光照剂量为10J/cm2时,光动力对PANC-1细胞达到最佳的实验效果,与对照组相比差异有显著性。在此实验参数条件下,流式细胞术(FCM)检测各组人胰腺癌细胞PANC-1凋亡率:HPD+PDT实验组达(36.40±4.21)%,明显高于单纯HPD(6.76±0.44)%,单纯PDT组(8.30±0.32)%及空白组(5.00±0.53)%三个对照组(P<0.05),三个对照组间差异无统计学意义(P>0.05)。结论:PDT光动力作用对体外培养人胰腺癌细胞PANC-1有明确抑制效应,并与HPD浓度及光照强度相关。     

光动力学疗法的单态氧剂量学研究进展

单态氧(1O2)是光动力学疗法(photodynamic therapy,PDT)过程中Ⅱ型光化学反应的主要细胞毒性物质.通过直接测量1O2发光强度预测PDT疗效已成为PDT剂量学研究的前沿热点,这种方法的最大优点在于能够克服现有其它剂量学方法中的光、光敏剂、氧分子,以及组织光学特性等因素之间的复杂相互影响,将PDT的...     

光动力学疗法治疗肝胆肿瘤的研究现状

介绍了光动力学疗法治疗肝胆肿瘤的实验室和临床研究现状,提出了光动力学疗法在治疗肝胆肿瘤面临的问题,并建议在腹腔镜手术中引入光动力学疗法,认为随着新型光敏剂及光源的开发应用,PDT将会成为治疗肝胆肿瘤的切实可行方法。     

Animal models for photodynamic therapy (PDT)

Photodynamic therapy (PDT) employs non-toxic dyes called photosensitizers (PSs), which absorb visible light to give the excited singlet state, followed by the long-lived triplet state that can undergo photochemistry. In the presence of ambient oxygen, reactive oxygen species (ROS), such as singlet oxygen and hydroxyl radicals are formed that are able to kill cancer cells, inactivate microbial pathogens and destroy unwanted tissue. Although there are already several clinically approved PSs for various disease indications, many studies around the world are using animal models to investigate the further utility of PDT. The present review will cover the main groups of animal models that have been described in the literature. Cancer comprises the single biggest group of models including syngeneic mouse/rat tumours that can either be subcutaneous or orthotopic and allow the study of anti-tumour immune response; human tumours that need to be implanted in immunosuppressed hosts; carcinogen-induced tumours; and mice that have been genetically engineered to develop cancer (often by pathways similar to those in patients). Infections are the second biggest class of animal models and the anatomical sites include wounds, burns, oral cavity, ears, eyes, nose etc. Responsible pathogens can include Gram-positive and Gram-negative bacteria, fungi, viruses and parasites. A smaller and diverse group of miscellaneous animal models have been reported that allow PDT to be tested in ophthalmology, atherosclerosis, atrial fibrillation, dermatology and wound healing. Successful studies using animal models of PDT are blazing the trail for tomorrow''s clinical approvals.     

Photodynamic therapy: a new antimicrobial approach to infectious disease?

Photodynamic therapy (PDT) employs a non-toxic dye, termed a photosensitizer (PS), and low intensity visible light which, in the presence of oxygen, combine to produce cytotoxic species. PDT has the advantage of dual selectivity, in that the PS can be targeted to its destination cell or tissue and, in addition, the illumination can be spatially directed to the lesion. PDT has previously been used to kill pathogenic microorganisms in vitro, but its use to treat infections in animal models or patients has not, as yet, been much developed. It is known that Gram-(-) bacteria are resistant to PDT with many commonly used PS that will readily lead to phototoxicity in Gram-(+) species, and that PS bearing a cationic charge or the use of agents that increase the permeability of the outer membrane will increase the efficacy of killing Gram-(-) organisms. All the available evidence suggests that multi-antibiotic resistant strains are as easily killed by PDT as naive strains, and that bacteria will not readily develop resistance to PDT. Treatment of localized infections with PDT requires selectivity of the PS for microbes over host cells, delivery of the PS into the infected area and the ability to effectively illuminate the lesion. Recently, there have been reports of PDT used to treat infections in selected animal models and some clinical trials: mainly for viral lesions, but also for acne, gastric infection by Helicobacter pylori and brain abcesses. Possible future clinical applications include infections in wounds and burns, rapidly spreading and intractable soft-tissue infections and abscesses, infections in body cavities such as the mouth, ear, nasal sinus, bladder and stomach, and surface infections of the cornea and skin.     

In vitro and in vivo matrix metalloproteinase expression after photodynamic therapy with a liposomal formulation of aminolevulinic acid and its methyl ester

Photodynamic therapy (PDT) is a well-known method for the treatment of malignant tumors, and its principles have been well established over the past 30 years. This therapy involves the application of a chemical called a photosensitizer and its subsequent excitation with light at the appropriate wavelength and energy. Topical photodynamic therapy with aminolevulinic acid (5-ALA) is an alternative therapy for many malignant processes, including nonmelanoma skin cancers such as basal-cell carcinoma (BCC). Our novel approach for this study was to use a liposomal formulation of 5-ALA and its methyl ester (commercially available as metvix) both in vitro and in vivo, and to check whether the liposome-entrapped precursors of photosensitizers can induce the expression of metalloproteinases (MMPs) in animal tumor cells and in other tissues from tumor-bearing rats and in selected cell lines in vitro. We also checked whether the application of tissue inhibitors of matrix metalloproteinases (TIMPs) has any effect on MMPs in the above-mentioned experimental models, and if they can cause complete inhibition of MMP expression. Immunohistochemical studies revealed that after the PDT, the intensity of expression of MMPs in healthy animals was very low and seen in single cells only. After the PDT in tumor-bearing rats, MMP-3 was expressed in the tumor cells with the highest intensity of staining in the tissues directly adjacent to the tumors, while MMP-2 and -9 were not found. In the control groups, there was no observed expression of MMPs. In vitro studies showed that MMP-3 was expressed in MCF-7 cells after PDT, but MMP-9 was not observed and MMP-2 was only seen in single cases. Our studies confirmed that the application of an MMP-3 inhibitor may block an induction of MMP-3 expression which had previously been initiated by PDT. The preliminary data obtained from cancer patients revealed that new precursors are effective in terms of PDT, and that using MMP inhibitors should be considered as a potential enhancing factor in clinical PDT.     

光动力疗法诱导增生滑膜细胞凋亡的初步研究

目的：观察光动力疗法（PDT）诱导类风湿性关节炎（RA）动物模型的增生滑膜细胞的凋亡情况。方法：兔AIA模型在关节类出现第七天进行PDT治疗,随机治疗一侧膝关节,另一侧作自身对照,免耳静脉注入HMME10mg/Kg,20分钟后,膝关节用金蒸气激光照射,激光波长627.8nm,功率密度100mW/cm^2,能量密度100J/cm^2,24小时后取膝关节滑膜作病理检查,并用脱氧核苷酸末端转移酶介导的缺口末端标记法（TUNEL）原位检测凋亡结论。结果：PDT治疗组凋亡阳性细胞较对照组明显增多,图像分析结果单位视野内阳性细胞数和面密度PDT治疗组高于对照组,统计学检验差异有显著性,凋亡细胞核直径PDT治疗组较小,与对照组相比,统计学检验差异有显著性。结论：PDT有可能通过诱发滑膜细胞的凋亡,使增生的滑膜细胞减少。     

Targeted photodynamic therapy of established soft-tissue infections in mice.

The worldwide rise in antibiotic resistance necessitates the development of novel antimicrobial strategies. Although many workers have used photodynamic therapy (PDT) to kill bacteria in vitro, the use of this approach has seldom been reported in vivo in animal models of infection. We have previously described the first use of PDT to treat excisional wound infections by Gram-(-) bacteria in living mice. However, these infected wound models involved a short timespan between infection (30 min) and treatment by PDT. We now report on the use of PDT to treat an established soft-tissue infection in mice. We used Staphylococcus aureus stably transformed with a Photorhabdus luminescenslux operon (luxABCDE) that was genetically modified to be functional in Gram-(+) bacteria. These engineered bacteria emitted bioluminescence, allowing the progress of the infection to be monitored in both space and time with a low light imaging charge-coupled device (CCD) camera. One million cells were injected into one or both thigh muscles of mice that had previously been rendered neutropenic by cyclophosphamide administration. Twenty-four hours later, the bacteria had multiplied more than one hundredfold; poly-L-lysine chlorin e6 conjugate or free chlorin e6 was injected into one area of infected muscle and imaged with the CCD camera. Thirty minutes later, red light from a diode laser was delivered as a surface spot or by interstitial fiber into the infection. There was a light dose dependent loss of bioluminescence (to <5% of that seen in control infections) not seen in untreated infections or those treated with light alone, but in some cases, the infection recurred. Treatment with conjugate alone led to a lesser reduction in bioluminescence. Infections treated with free chlorin e6 responded less well and the infection subsequently increased over the succeeding days, probably due to PDT-mediated tissue damage. PDT-treated infected legs healed better than legs with untreated infections. This data shows that PDT may have applications in drug-resistant soft-tissue infections.     

Low‐dose angiostatic tyrosine kinase inhibitors improve photodynamic therapy for cancer: lack of vascular normalization

Photodynamic therapy (PDT) is an effective clinical treatment for a number of different cancers. PDT can induce hypoxia and inflammation, pro‐angiogenic side effects, which may counteract its angio‐occlusive mechanism. The combination of PDT with anti‐angiogenic drugs offers a possibility for improved anti‐tumour outcome. We used two tumour models to test the effects of the clinically approved angiostatic tyrosine kinase inhibitors sunitinib, sorafenib and axitinib in combination with PDT, and compared these results with the effects of bevacizumab, the anti‐VEGF antibody, for the improvement of PDT. Best results were obtained from the combination of PDT and low‐dose axitinib or sorafenib. Molecular analysis by PCR revealed that PDT in combination with axitinib suppressed VEGFR‐2 expression in tumour vasculature. Treatment with bevacizumab, although effective as monotherapy, did not improve PDT outcome. In order to test for tumour vessel normalization effects, axitinib was also applied prior to PDT. The absence of improved PDT outcome in these experiments, as well as the lack of increased oxygenation in axitinib‐treated tumours, suggests that vascular normalization did not occur. The current data imply that there is a future for certain anti‐angiogenic agents to further improve the efficacy of photodynamic anti‐cancer therapy.     

Adjuvant treatment for complement activation increases the effectiveness of photodynamic therapy of solid tumors.

Phototoxic lesions generated in tumor tissue by photodynamic therapy (PDT) are recognized by the host as a threat to the integrity and homeostasis at the affected site. Among the canonical pathways invoked by the host for dealing with this type of challenge is the activation of the complement system, integrating proteins that serve as molecular sensors of danger signals produced by PDT and those initiating signalling cascades coupled into the network of inflammatory and immune responses. Since the activated complement system is a salient participant of the antitumor response produced by PDT, it is worth exploring whether its manipulation can be exploited for the therapeutic benefit. Using mouse tumor models, the present study examined the potential of representative complement-activating agents to act as effective adjuvants to PDT. Tumor-localized treatment with zymosan, an alternative complement pathway activator, reduced the recurrence-rate of PDT-treated tumors, markedly increasing the percentage of permanent cures. In contrast, a similar treatment with heat aggregated gamma globulin (complement activator via the classical pathway) was of no significant benefit as a PDT adjuvant. Systemic complement activation with streptokinase treatment had no detectable effect on complement deposition at the tumor site without PDT, but it augmented the extent of complement activity in PDT-treated tumors. This finding based on immunohistochemistry analysis explains the results of tumor therapy experiments, which showed that systemic treatment with streptokinase or a similar agent, urokinase, enhances the PDT-mediated tumor response. Zymosan and streptokinase administrations produced no beneficial results with PDT of tumors growing in complement-deficient mice. This study, therefore, establishes the potential of complement-activating agents to serve as effective adjuvants to PDT for cancer treatment.     

Photodynamic therapy combined with a cysteine proteinase inhibitor synergistically decrease VEGF production and promote tumour necrosis in a rat mammary carcinoma

OBJECTIVES: Photodynamic therapy (PDT) and inhibition of cathepsin B proteases by cystatin (cysteine proteinase inhibitor, CPI) are potential new tumour treatment modalities. We have investigated the efficacy of PDT and CPI alone and in combination on a solid mammary carcinoma transplanted into Wistar rats. MATERIALS AND METHODS: Intraperitoneally injected single doses of chlorine e6 or HpD as photosensitizers were excited at 630 nm (90 J/cm(2)). CPI (500 micro g per animal) was injected around the tumour daily during the 8-day treatment. Inoculation of tumour was either on day 1 of the protocol, or 8 days before. On day 8, tumour size was measured, tumour necrosis and vascularization were determined based on haematoxylin and eosin (H&E)-stained sections and serum vascular endothelial growth factor (VEGF) levels measured using an enzyme-linked immunosorbent assay kit. RESULTS: No differences (two-way anova) were found for treatments started with various time lags. At doses where CPI or PDT alone had no or negligible effect, their combination caused a marked (P < 0.001) decrease in serum VEGF, paralleled by a significant decrease in tumour size and number of capillary vessels, and a significant increase in necrosis (up to 80% of the tumour tissue). CONCLUSIONS: The combination of PDT and CPI could be a useful approach in tumour therapy as the two agents appear to be synergistic and probably decrease VEGF production by the tumour tissue.     

Synthesis and photobiological study of a novel chlorin photosensitizer BCPD-18MA for photodynamic therapy

This paper reports synthesis and photobiological properties of a novel chlorin photosensitizer BCPD-18MA. Cytotoxicity, cellular uptake, subcellular location, biodistribution, photodynamic therapy (PDT) efficiency, cell apoptosis as well as histological analysis of the liposomal-delivered BCPD-18MA (L-BCPD-18MA) was studied using mammary adenocarcinoma MDA-MB-231 cells and Lewis lung carcinoma (LLC) implanted in C57BL/6 mice as experimental models. The results showed that L-BCPD-18 was incorporated rapidly into MDA-MB-231 cells and localized partially in mitochondria. L-BCPD-18 induced cell apoptosis by PDT. In addition, biodistribution of L-BCPD-18MA in LLC-bearing mice demonstrated a fast clearance rate of the drug and good skin-related tumor selectivity. Finally, entrapment of BCPD-18 into liposomes resulted in a dramatic impairment of dark toxicity and a notable improvement of PDT antitumor efficacy in vitro. Compared with liposomal-delivered BPDMA (L-BPDMA), L-BCPD-18MA exhibited low dark toxicity and high PDT efficiency on MDA-MB-231 cells. The photodynamic efficacy of L-BCPD-18MA on LLC-bearing mice is comparable to that of L-BPDMA, implying that L-BCPD-18MA is a potential antitumor candidate for PDT.     

Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro

In recent years, there has been the difficulty in finding more effective therapies against cancer with less systemic side effects. Therefore Photodynamic Therapy is a novel approach for a more tumor selective treatment.Photodynamic Therapy (PDT) that makes use of a nontoxic photosensitizer (PS), which, upon activation with light of a specific wavelength in the presence of oxygen, generates oxygen radicals that elicit a cytotoxic response¹. Despite its approval almost twenty years ago by the FDA, PDT is nowadays only used to treat a limited number of cancer types (skin, bladder) and nononcological diseases (psoriasis, actinic keratosis)².The major advantage of the use of PDT is the ability to perform a local treatment, which prevents systemic side effects. Moreover, it allows the treatment of tumors at delicate sites (e.g. around nerves or blood vessels). Here, an intraoperative application of PDT is considered in osteosarcoma (OS), a tumor of the bone, to target primary tumor satellites left behind in tumor surrounding tissue after surgical tumor resection. The treatment aims at decreasing the number of recurrences and at reducing the risk for (postoperative) metastasis.In the present study, we present in vitro PDT procedures to establish the optimal PDT settings for effective treatment of widely used OS cell lines that are used to reproduce the human disease in well established intratibial OS mouse models. The uptake of the PS mTHPC was examined with a spectrophotometer and phototoxicity was provoked with laser light excitation of mTHPC at 652 nm to induce cell death assessed with a WST-1 assay and by the counting of surviving cells. The established techniques enable us to define the optimal PDT settings for future studies in animal models. They are an easy and quick tool for the evaluation of the efficacy of PDT in vitro before an application in vivo.