Photodiagnosis and Photodynamic Therapy

Published by Elsevier
Print ISSN: 1572-1000
Photodynamic effect was a chance discovery early in the 1900s, demonstrating the lethal effects of light activated chemicals on living cells. Although the application of the principles of photodynamic effect to patients' treatment and what became photodynamic therapy (PDT) was practiced in 1960s and 1970s, clinical trials were only started in the 1980s, following successful synthesis of clinically usable photosensitisers (drugs) and the manufacturing of light sources. We briefly review and highlight some of the landmarks of the development of clinical PDT in Europe.
Photodynamic therapy, the fourth oncological interventional modality has proved its success in the management of variety of pathologies involving the human body. Our aim in this prospective clinical study was to continue evaluating the outcome following ultrasound-guided interstitial PDT of pathologies involving the human body. Patients' reports on quality of life with clinical and radiological evaluation were the main end point parameters used to assess the outcome. One hundred and ten patients were referred to the UCLH Head and Neck Centre, London for treatment of various deep-seated pathologies. These included tumours in the head and neck as well as vascular anomalies of the limbs. After multidisciplinary discussion, all patients underwent interstitial photodynamic therapy (iPDT) under general anaesthesia, using 0.15mg/kg mTHPC as the photosensitising agent. Following treatment, patients were followed-up for a mean of 26 months. Four out of five patients who presented with visual problems reported improvement after treatment. Also, 27/32 reported improvement of breathing. Improvement of swallowing was reported by 30/37 patients; while speech improvement was evident in 22/29 patients and 43/52 reported reduction in the disfigurement caused by their pathology. Seven out of nine patients with impeded limb function reported some degree of improvement. Clinical assessment showed that nearly half of the patients had "good response" to the treatment and 5 became disease free. Moderate clinical response was reported by 39 patients. Radiological assessment comparing radiological imaging 6-week post-PDT to the baseline showed moderate response in 45 patients and significant response in 32 patients. This study on 110 patients with deep-seated pathologies undergoing interstitial photodynamic therapy provided further evidence that PDT is a useful modality in the management of these pathologies that are otherwise resistant to conventional treatments, and with minimal side effects.
Photodynamic therapy (PDT) was investigated using the phthalocyanine photosensitizer Zinc (II) 2,9,16,23-tetrakis (methoxy) phthalocyanine (ZnPc(OCH(3))(4)) on BALB/c mice. Animals bearing tumor were treated with 0.2mg/kg body weight (bw) ZnPc(OCH(3))(4) and 24h later were irradiated with 70, 140 and 210 J/cm(2) of visible light from a source delivering 39 mW/cm(2). In this study, we have tested the efficiency of ZnPc(OCH(3))(4) liposomal formulation on mice. Biodistribution studies were performed in tumor-free mice and tumor-bearing mice at various time points up to 24h after ZnPc(OCH(3))(4)-PDT treatment. The tumor sizes were evaluated over different period in parallel experiments. The maximal efficiency and selectivity of photosensitizer accumulation in tumor tissue take place at 24h after drug administration of 0.2mg/kg bw ZnPc(OCH(3))(4). In the tumor sections for biochemical studies, apoptosis was visualized by activation of caspase-3. ZnPc(OCH(3))(4)-PDT tumors showed a significant delay in growth as compared to untreated control mice. In all cases, ZnPc(OCH(3))(4)-PDT-treated tumors showed a significant regression. The results indicated a dramatic decrease of tumors size after 10 days post-irradiation with 210 J/cm(2) and no recurrence of the disease was detectable within at least 90 days. The phototherapeutic agent ZnPc(OCH(3))(4) demonstrated preferential accumulation in tumor in comparison with skin tissues, except in the case of kidney. The ratio of tumor/skin tissues ranged a value of 8. These results suggest that ZnPc(OCH(3))(4)-PDT may be of particular importance in the treatment of accessible malignancies.
Photodynamic therapy (PDT) is an innovative minimally invasive therapy that has great potential for both tumor ablation and normal tissue preservation. However, while in recent years the standards of surgery, radiation and chemotherapy have dramatically improved in terms of outcomes and morbidity, the same cannot be said of PDT in general and Photofrin((R))-based PDT in particular. As currently practiced PDT dosimetry has not really improved tumor ablation and diminished side effects over reports from two decades ago. We critically examine the clinical variables available for PDT dosimetry and conclude that the simple maneuver of diminishing drug dose, with an appropriate increase in light dose, can enhance disease control with a significantly lower risk of morbidity. This conclusion should also be applicable to most systemically introduced photosensitizer.
Photodynamic therapy is an established cancer treatment in which a photosensitizing agent is activated by exposure to light thus generating cytotoxic reactive oxygen species that cause cellular damage. A new photosensitizer synthesized at Curie Institute was used to treat retinoblastoma xenografts in mice, a glycoconjugated meso substituted porphyrin derivative, that showed some retinoblastoma cell affinity. The longitudinal follow-up of the tumors was carried out by (23)Na MRI (without adding exogenous contrast agents) to map the extracellular compartment and to characterize cell packing. Two regimens were followed to target either blood vessels alone or blood vessels and cancer cells simultaneously. Only the protocol targeting both cancer cells and blood vessels effectively induces cellular death, confirmed by histology at the end of the experiment. Sodium MRI evidences a huge change in the cellular density of tumors only 24h after a double targeting (vascular and cellular) PDT treatment. We suggest that this change was possibly due to a bystander effect that can be promoted by the intercellular signaling favored by the high cellular density of retinoblastoma. These results indicate that non-invasive (23)Na imaging (which detects the tumor response to treatment from very early stages) in association with non-mutagenic therapies represents an effective option for tailored and individualized clinical treatments.
Hyperbranched polymers represent a new class of drug-delivery vehicle that can be used to prepare nanoparticles with uniform size distribution. In this study we prepared covalent conjugates between the photosensitizer chlorin(e6) and hyperbranched poly(ether-ester), HPEE. HPEE-ce6 nanoparticles were synthesized by carbodiimide-mediated reaction between HPEE and ce6, and characterized by ultraviolet-visible absorption spectroscopy (UV-Vis), and transmission electron microscopy (TEM). The uptake and phototoxicity of HPEE-ce6 nanoparticles towards human oral tongue cancer CAL-27 cells was detected by confocal laser scanning microscopy (CLSM) and MTT assay, respectively. The absorption peak of HPEE-ce6 nanoparticles was red-shifted 12-nm compared with ce6, and TEM showed uniform nanoparticles with a diameter of 50-nm. HPEE-ce6 nanoparticles were taken up by CAL-27 cells after 4h incubation and localized in the cytoplasm. The MTT assay showed a significantly (P<0.05) higher phototoxicity compared to free ce6 after 12 J/cm² of 660-nm laser illumination. This is the first time to our knowledge that hyperbranched polymers have been used in PDT drug delivery.
Background: Fluorescence diagnostics uses the ability of tissues to fluoresce after exposition to a specific wavelength of light. The change in fluorescence between normal and progression to cancer allows to see early cancer and precancerous lesions often missed by white light. Aim: To improve by computer image processing the sensitivity of fluorescence images obtained during examination of skin, oral cavity, vulva and cervix lesions, during endoscopy, cystoscopy and bronchoscopy using Xillix ONCOLIFE. Methods: Function of image f(x,y):R2 --> R3 was transformed from original color space RGB to space in which vector of 46 values refers to every point labeled by defined xy-coordinates- f(x,y):R2 --> R46. By means of Fisher discriminator vector of attributes of concrete point analalyzed in the image was reduced according to two defined classes defined as pathologic areas (foreground) and healthy areas (background). As a result the highest four fisher's coefficients allowing the greatest separation between points of pathologic (foreground) and healthy (background) areas were chosen. In this way new function f(x,y):R2 --> R4 was created in which point x,y corresponds with vector Y, H, a*, c2. In the second step using Gaussian Mixtures and Expectation-Maximisation appropriate classificator was constructed. This classificator enables determination of probability that the selected pixel of analyzed image is a pathologically changed point (foreground) or healthy one (background). Obtained map of probability distribution was presented by means of pseudocolors. Results: Image processing techniques improve the sensitivity, quality and sharpness of original fluorescence images. Conclusion: Computer image processing enables better visualization of suspected areas examined by means of fluorescence diagnostics.
Our previous studies found that topical 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (ALA-PDT) with a light dose of 100J/cm(2) is very effective for human oral precancerous lesions. In this study, 20 7,12-dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch precancerous lesions were treated by topical ALA-PDT with a light dose of either 75J/cm(2) (n=10) or 100J/cm(2) (n=10) using a 640-nm light-emitting diode (LED) light to test which light dose could achieve a better clinical outcome. The 10 precancerous lesions treated by 75-J ALA-PDT showed complete response in 8 after an average of 3.4 (range, 2-6) treatments and partial response in 2. The 10 precancerous lesions treated by 100-J ALA-PDT demonstrated complete response in 7 after an average of 4.4 (range, 3-6) treatments and partial response in 3. Fisher exact test showed no significant difference in clinical outcome between these two treatment modalities (p=1.000). One complete-response precancerous lesion in the 75-J ALA-PDT group recurred at the end of 19-week follow-up and another complete response precancerous lesion in the 100-J ALA-PDT group recurred at the end of 16-week follow-up. Both recurrence lesions were treated by the original topical ALA-PDT regimen and demonstrated complete response after 3 PDT treatments. Furthermore, the 5 partial-response precancerous lesions developed into squamous cell carcinomas after 30-week follow-up. Our findings indicate that both the 75-J and 100-J topical ALA-PDT treatment modalities are very effective for DMBA-induced hamster buccal pouch precancerous lesions and no significant difference in clinical outcome between these two treatment modalities.
The efficiency of photodynamic therapy (PDT) used in combination with Indocyanine green (ICG) and the light emitting diode (LED) on oral cancer was evaluated. The safety risk of ICG is known to be very low and ICG has a strong peak in the vicinity of 700-800nm range which is thought to be a good candidate as a photosensitizer for PDT due to the deep penetration depth into the oral cancer tissue. The radiation intensity of homemade LED array was 50mW/cm(2) at 0.5A. To evaluate the maximum efficiency of ICG-PDT on oral cancer, different wavelengths, ICG concentrations, irradiation interval times after administering ICG, and the time durations after PDT were tested. The cytotoxicity was determined by MTT assay, and apoptosis and necrosis were also observed by double staining with SYTO 16 green and PI. The IC(50) value was 10μM when 785nm was irradiated, while it was very low in comparison with 630nm and 895nm. The values were not very different with varying interval time. The percentage of apoptotic cells increased gradually to 84% at 6h after 20μM ICG-PDT and the percentage of necrotic cells dramatically increased to 65% at 3h after 200μM ICG-PDT. Using ICG-PDT with 785nm LED light, the LED is regarded as a satisfying light source since cancer treatments in the oral region do not require focusing and increased depth of penetration due to longer wavelength enhances treatment effectiveness.
Immediate response of ICG-PDT measured by MTT cell viability assay at time 0 (right after treatment). Human MDA-MB231 breast cancer cells incubated in 96-well plates were divided into 4 groups, 16 wells each (Control, ICG, Light, and ICG-PDT). After light exposure the viability of cells in each well was measured by MTT analysis right after treatment. The effect of ICG-PDT treatment is significantly different (p < 0.01, n = 16) than other groups.
Response of ICG-PDT measured by MTT cell viability assay at time 3, 6, 9, 12, 24, 48 h after treatment. Human MDAMB231 breast cancer cells incubated in 96-well plates were divided into 4 groups (Control, ICG, Light, and PDT). After light exposure the viability of cells in each well were measured my MTT analysis 3, 6, 9, 12, 24 and 48 h. ICG-PDT is significantly different from other three groups at all time points (p < 0.01, n = 16).
Relative viability of MDA-MB231 human breast cancer cells treated with ICG-PDT according to control groups at time 3-48 h. Cell viability decreased to 4.6%, 48 h after treatment.
Photodynamic therapy (PDT), due to its positive outcomes in clinical applications, easiness of practice and few side effects, is a good candidate for an efficient treatment of cancer. Indocyanine green (ICG), a water-soluble, anionic tricarbocyanine and non-toxic molecule is a promising photosensitive agent for PDT applications on tumor cells. ICG exhibits strong maximum absorption at around 805 nm which will be an advantage for its use in PDT; light at that wavelength can be used to treat deeper tumors. In this study the inhibitory growth effects of ICG-PDT on MDA-MB231 human breast cancer cells were investigated in a time course experiment. Cells were irradiated with a continuous wave diode laser (lambda=809 nm, 60 mW, 24 J cm(-2)). Cell viability was measured by MTT assay 0, 3, 6, 9, 12, 24 and 48h after light irradiation. The results showed that ICG-PDT application exerted its photo-oxidative effect on MDA-MB231 breast cancer cells immediately. Relative cell viability was determined throughout the 48h time course, and a consistent decrease was observed after ICG-PDT applications. In conclusion, ICG when used in combination with near-infrared light showed a very fast (within 3h) and persistent (up to 48h) photo-toxic effect on MDA-MB231 human breast cancer cells.
Photodynamic therapy (PDT) is based on the preferential accumulation of photosensitizer in cancer cells with subsequent cytotoxicity mediated by singlet oxygen production after light excitation. As photosensitizers accumulate also in the surrounding non-cancer cells, the risk of damaging them by photosensitization is a limitation of PDT. Thus, minimizing the side-effects of PDT on normal cells is one of the challenging problems in medical practice. This paper studies the PDT side-effects of PVP-Hypericin (PVP: polyvinylpyrrolidone) photosensitizer excited with continuous or pulsed irradiation, on combined cell lines of human lung carcinoma epithelial cells (A549) and normal primary human lung fibroblast cells (HLF). In vitro PDTs are performed using pulsed or continuous irradiation with irradiance intensities I(*)=1.59, 6.34 and 14.27mW/cm(2). The LED pulse lengths L are 0.127, 1.29, 13, 54.5 and 131ms. Then fluorescence and phototoxicity of PVP-Hypericin in the A549 cancer cells are compared with those of HLF normal cells. Although, PVP-Hypericin accumulates more in A549 cancer cells, the results show that HLF cells produce dose-dependent photoreactions in the presence of photosensitizer. PVP-Hypericin induces the most optimized anticancer efficacy with moderate side-effects for I(*)=14.27mW/cm(2) and L=131ms.
Photodynamic therapy (PDT) is a therapeutic modality used for treating cancerous cells. It has been previously shown that mixed sulfonated metallophthalocyanine complex, zinc sulfophthalocyanine (ZnPcS(mix)) is effective in destroying lung cancer cells. This study aimed to determine subcellular localization of ZnPcS(mix) and its effect on two cancer cell lines. ZnPcS(mix) was activated at a wavelength of 680 nm with 5 J/cm². Colon (DLD-1) and lung (A549) cancer cell lines were used. Subcellular localization of ZnPcS(mix) was determined by fluorescence microscopy. Toxicity of PS alone and combination of light and PS (PDT) was determined by cell morphology, viability, proliferation and cytotoxicity. Cells which received no irradiation (0 J/cm²), irradiation alone (5 J/cm²) or treated with PS alone (no irradiation) served as controls. ZnPcS(mix) localized in both lysozomes and mitochondria in both A549 and DLD-1 cells. A549 cells treated with PDT showed a significant decrease in viability and proliferation in all PS concentrations used, while in DLD-1 cells a significant decrease was seen with concentrations of 10, 20 and 40 μM. In absence of light, ZnPcS(mix) did not result in cellular toxicity in A549 cells whereas in DLD-1 cells it resulted in a reduction in cell proliferation only at a concentration of 40 μM. ZnPcS(mix) was effective in inducing cell death in both cell lines when localized in vital organelles such mitochondria and lysozomes which are essential for cell functioning. Photoactivated ZnPcS(mix) affected the cells at different concentration and yielded good therapeutic results in vitro.
Recently, 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) is being widely used in cancer therapy owing to the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX) after the administration of ALA. In the present study, by focusing on genes involved in the porphyrin biosynthesis pathway, we aimed to explore biomarkers that are predictive for the efficacy of ALA-PDT. We used five lines of human gastric cancer cells to measure the ALA-based photocytotoxicity. ALA-induced production of PpIX in cancer cells was quantified by fluorescence spectrophotometry. To examine the potential involvement of PEPT1 and ABCG2 in the ALA-PDT sensitivity, stable cell lines overexpressing PEPT1 were established and ABCG2-specific siRNA used. We observed that three cell lines were photosensitive, whereas the other two cell lines were resistant to ALA-based photocytotoxicity. The ALA-based photocytotoxicity was found to be well correlated with intracellular PpIX levels, which suggests that certain enzymes and/or transporters involved in ALA-induced PpIX production are critical determinants. We found that high expression of the peptide transporter PEPT1 (ALA influx transporter) and low expression of the ATP-binding cassette transporter ABCG2 (porphyrin efflux transporter) determined ALA-induced PpIX production and cellular photosensitivity in vitro. PEPT1 and ABCG2 are key players in regulating intracellular PpIX levels and determining the efficacy of ALA-based photocytotoxicity against gastric cancer cells in vitro. Evaluation of the expression levels of PEPT1 and ABCG2 genes could be useful to predict the efficacy of ALA-PDT. Primers specific to those target genes are practical and useful biomarkers for predicting the photo-sensitivity to ALA-PDT.
Currently, 5-aminolevulinic acid-based photodynamic diagnosis (ALA-PDD) is used to detect tumors during surgery and exploit tumor-specific accumulation of protoporphyrin IX (PpIX) after administration of ALA. In a recent study, we showed that the human ATP-binding cassette transporter ABCG2 plays a key role in the regulation of PpIX as a specific exporter. However, coproporphyrin III (CPIII) was also detected in urine after ALA administration in patients with tumor, indicating the presence of a CPIII transporter. We used two lines of human gastric cancer cells to measure the ALA-induced porphyrin metabolism. Intracellular and extracellular porphyrin levels and expressions of transporter were determined. In the present study, we showed that although ABCG2 did not transport CPIII, plasma membrane ABCB6 did. Moreover, under conditions of hypoxia, the expression of ABCB6 in plasma membrane was upregulated, resulting in increased extracellular CPIII concentrations. These data indicate that the expression of ABCB6 in plasma membrane is important for porphyrin accumulation after ALA administration, including hypoxic conditions. Copyright © 2015. Published by Elsevier B.V.
A detection method widely used of late in cancer surgery is 5-aminolevulinic acid-based photodynamic diagnosis (ALA-PDD), which relies on the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX) after the administration of ALA. In this regard, we recently reported that peptide transporter PEPT1 and human ATP-binding cassette transporter ABCG2 are key players in regulating intracellular PpIX levels. In the present study, we re-evaluated in vivo the expression of genes involved in the porphyrin biosynthesis pathway. Using quantitative real-time (qRT)-PCR, we measured the mRNA levels in a clinical specimen of bladder cancer from a patient who had been subjected to ALA-PDD. We confirmed that PEPT1 and ABCG2 are major contributors to the regulation of tumor-specific PpIX accumulation. qRT-PCR analysis revealed a predominantly high level of PEPT1 mRNA and a very low level of ABCG2 mRNA in the bladder cancer, corresponding to the roles of these genes in vitro. These findings were further confirmed by immunohistochemical studies with PEPT1- and ABCG2-specific antibodies. The induction of PEPT1 gene and the suppression of ABCG2 gene expression are among the key molecular mechanisms underlying tumor-specific PpIX accumulation after the administration of ALA in bladder cancer.
Barrett's high grade dysplasia (HGD) is a pre-malignant condition which requires treatment with either oesophagectomy or ablative endoscopic therapy. Endoscopic ablative techniques have evolved through Photodynamic Therapy (PDT) to more recently radiofrequency ablation (RFA). Although RFA has superseded PDT due to improved efficacy and safety profile there remains a significant cohort of patients previously treated by PDT where the long term outcome is unclear. This study's aim was to assess the long term efficacy of PDT in patients with Barrett's HGD. Between June 2002 and 2007 21 patients (16 male, median age 70) underwent PDT for HGD in Barrett's oesophagus. Patients received intravenous photosensitiser Photofrin (Porfimer sodium) forty eight hours prior to endoscopic light activation by laser light at 630nm. The patients returned at 6-12 weekly intervals for repeat endoscopy and biopsy. Sixteen patients remained free of HGD at median 62 (range 36-114) months. Three patients developed adenocarcinoma at 47, 48 and 54 months (15%). Two patients were treated endoscopically with RFA and YAG laser, while one patient had surgical resection. Four patients developed recurrent HGD treated with repeat PDT. There was a significant reduction in length of Barrett's segment (from 5cm to 3cm) post PDT. The stricture rate requiring endoscopic therapy was 37% and 10% of patients developed photosensitivity reactions. PDT successfully ablated HGD in 84% of patients and could therefore still be considered an effective salvage treatment for this condition in patients with co-morbidities precluding them for surgical resection.
There have been considerable efforts to develop photodynamic therapy (PDT) for cancer, in which photoirradiation of a sensitizer delivered near cancer cells results in the conversion of oxygen into active species, causing cell destruction. Aiming at the best cancer selectivity, one PDT method employed protoporphyrin IX (PPIX), which selectively accumulated in cancer cells after oral administration of 5-aminolevulinic acid (ALA). The drawback, however, is that blue incident lights are required to excite PPIX, resulting in low tissue penetrability, and therefore limiting its application to surface cancers. To overcome the low penetrability of the incident light, we employed a light energy upconverter, lanthanide nanoparticle (LNP), which, upon irradiation with highly penetrative near-infrared (NIR) radiation, emits visible light within the Q-band region of PPIX absorbance allowing its sensitization. To discover the optimum conditions for the LNP-assisted PDT, the cytotoxicity and PPIX-sensitizability of LNPs were first studied. Then, the LNP-assisted PDT was validated using the MKN45 cell line: cells were pretreated with ALA and LNP, irradiated with a 975-nm diode laser, and subjected to MTT assay to measure cell viability. The singlet oxygen generation on NIR-irradiation of the PPIX-LNP mixture was proved, indicating that the emission from LNP could excite the PPIX sensitizer. An intermittent NIR-irradiation for 32min of MKN45, pretreated with LNP (1mg/mL) and ALA (2mM), caused 87% cell destruction. The potential applicability of the NIR-irradiation PDT with ALA- and LNP-pretreated cancer cells was demonstrated.
Dermatological methyl-aminolevulinate photodynamic therapy (MAL-PDT) is utilized to successfully treat dermatological conditions. This study monitored fluorescence changes attributed to the accumulation and destruction of the photosensitizer, protoporphyrin IX (PpIX), at several different stages during the first and second treatments of clinical dermatological MAL-PDT. A commercially available, non-invasive, fluorescence imaging system (Dyaderm, Biocam, Germany) was utilized to monitor fluorescence changes during the first and second MAL-PDT treatments in seventy-five lesions. The clinical data indicated statistically significant increases in fluorescence within lesions following the application of MAL for both treatments (P<0.001 and P<0.01 respectively) and subsequent statistically significant decreases in fluorescence within the lesions following light irradiation for both treatments (P<0.001 and P<0.01 respectively) whilst normal skin fluorescence remained unaltered. Lesions receiving a second treatment accumulated and dissipated significantly less PpIX (P<0.05) than during the first treatment. No significant differences were noted in PpIX accumulation or dissipation during MAL-PDT when gender, age, lesion type and lesion surface area were considered. It can therefore be concluded that PpIX fluorescence imaging can be used in real-time to assess PpIX levels during dermatological PDT. Similar observations were recorded from the three currently licensed indications indicating that the standard 'one size fits all' protocol currently employed appears to allow adequate PpIX accumulation, which is subsequently fully utilized during light irradiation regardless of patient age, gender or lesion surface area.
Acne vulgaris is a common dermatological disorder. Topical photodynamic therapy (PDT)-mediated with aminolevulinic acid (ALA) or methyl aminolevulinic acid (MAL) has been successfully used in the treatment of moderate to severe acne. The purpose of this case report is to highlight the feasibility of using a repeat weekly short-cycle ALA-PDT to treat severe facial acne lesions refractory to systemic retinoid and antibiotics.
To evaluate the effectiveness of topical 5-aminolevulinic acid (ALA)-medicated photodynamic therapy (PDT) for the treatment of severe acne vulgaris. A total of 78 Chinese patients with Grade 4 severe facial acne were treated with 1-3 courses of ALA PDT. ALA cream (10%) was applied topically to acne lesions for 3 h. The lesions were irradiated by a LED light of 633 nm at dose levels of 50-70 J/cm(2) at 66 mW/cm(2). Clinical assessment was conducted before and after treatment up to 6 months. 22% of patients showed excellent improvement after one-course treatment and another 34% showed excellent improvement after two-course. The rest (44%) required three-course treatment to further reduce the number and size of residual lesions. Adverse effects were minimal. The symptoms and signs in recurrent cases (14%) were much milder and responded well to conventional topical medication. ALA PDT is a simple, safe and effective therapeutic option for the treatment of severe acne. Further studies to fully understand its mechanisms and optimize its effectiveness are needed.
To investigate the efficacy and safety of low-concentration 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in the treatment of different severity of acne vulgaris and optimize the treatment regimen. A self-controlled multicenter clinical trial was carried out in 15 centers throughout China. A total of 397 acne patients of grade II-IV received 3- or 4-session PDT treatment. 5% ALA gel was applied topically to acne lesions for 1h incubation. The lesions were irradiated by a LED light of 633nm at dose levels of 96-120J/cm(2). Clinical assessment was conducted before and after every treatment up to 8 weeks. The effective rate overall and of grade II, III and IV are 82.1%, 71.6%, 79.6% and 88.2%, respectively. The effective rate rises significantly proportionally to the severity of acne (P<0.01). No significant differences are found in the efficacy between patients received 3-session and 4-session PDT treatments (P>0.05). The count of inflammatory and non-inflammatory acne lesions gradually decrease after each treatment (P<0.01) and during the 8-week follow up (P<0.01 or P<0.05). Maximum efficacy is obtained at 8 weeks after the treatment completion. A low-dose topical ALA-PDT regimen using 5% ALA, 1h incubation and red light source of 3 treatment sessions is suggested as optimal scheme for the treatment of different severity of acne vulgaris in Chinese patients. Superior efficacy is found in severe cystic acne of grade IV with mild side effects.
Photodynamic therapy (PDT) is a promising treatment modality for skin malignancies. Aminolevulinic acid (ALA)-PDT for the treatment of actinic keratosis (AK) has been well studied in Europe and North America. However, there have only been a few clinical studies that have evaluated ALA-PDT for the treatment of AK in Chinese patients. The objective of our study was to determine the therapeutic response of Chinese patients with AK lesions to photodynamic therapy (PDT), and the histologic changes associated with PDT. Forty-two patients with a total of 56 AK lesions on the face were enrolled in this study. After the application of 20% ALA under occlusion for 5h, the lesions were illuminated by diode laser (λ=630nm; intensity 100mW/cm(2)) for 30min. All patients were reviewed at intervals of at least 2 weeks. One month after therapy, response to PDT was evaluated and treatment repeated if necessary. At 1 month after PDT, a complete response was achieved in 85.71% of treated lesions. The remaining lesions received one or two additional PDT treatments, and were eventually cleared. Clinically, there was no significant scarring or pigmentary changes after therapy. In this small study, PDT using topical ALA was demonstrated to be a safe and effective therapy for AK lesions with excellent cosmetic outcome. It is a promising treatment that merits further study in China.
Hypericin is a photo-active dye originating from the St. John's wort. Two patients with disseminated superficial actinic porokeratosis (DSAP) were treated with photodynamic therapy (PDT) using topical hypericin. Although a partial response was obtained in one patient topical hypericin-PDT does not emerge as a promising treatment for DSAP.
The aim of this study was to clarify the mechanism of accumulation of 5-aminolevulinic acid (ALA)-dependent protoporphyrin IX (PpIX), ALA-photodynamic therapy (PDT)-induced cell death and enhanced efficiency by a ferrochelatase inhibitor in prostate cancer PC-3 cells. The accumulation of ALA-induced PpIX in PC-3 cells was observed by fluorescence microscopy and measured by flow cytometry analysis. The efficiency of ALA-PDT was analyzed by flow cytometry and assessed by cell death, caspase-3 activity and mitochondrial membrane potential. The ALA-PDT-promoting effects of ferrochelatase inhibitors, such as deferoxamine and NOC-18, were also analyzed. We confirmed the results obtained in vivo with an animal model using nude mice. ALA-induced PpIX accumulation increased in time- and ALA concentration-dependent manners. ALA-PDT decreased the levels of mitochondrial membrane potential, and induced cell death occurred by both apoptosis and necrosis. Inhibition of ferrochelatase by deferoxamine and NOC-18 led to increase of PpIX accumulation and enhanced effect of ALA-PDT in PC-3 cells. In vivo, the degeneration of tumor tissue by ALA-PDT was observed within a broader range and led to apoptosis and necrosis. This study demonstrated ALA-PDT induced PC-3 cell death by the mechanisms of both necrosis and apoptosis through a caspase-independent mitochondrial pathway. Inhibition of ferrochelatase enhanced these effects, suggesting that ferrochelatase played an important role in ALA-PDT. ALA-PDT could be a new modality for focal therapy of prostate cancer.
Photodynamic therapy (PDT) is an elegant minimally invasive oncologic therapy. The clinical simplicity of photosensitizer (PS) drug application followed by appropriate illumination of target leading to the oxygen dependent tumor ablative Photodynamic Reaction (PDR) has gained this treatment worldwide acceptance. Yet the true potential of clinical PDT has not yet been achieved. This paper will review current mechanisms of action and treatment paradigms with critical commentary on means to potentially improve outcome using readily available clinical tools.
The purpose of this study was to investigate the photoefficacies of protoporphyrin IX (PpIX) generated by drug precursor 5-aminolevulinic acid (ALA) and its hexyl ester (H-ALA) on two human non-small lung carcinoma cell lines (H460/Bcl-2 and H460/neo). Drug uptake and the photoefficacies of PpIX were measured by flow cytometry and MTT assay; while the mode of cell death and alternation of signal transduction pathways were studied with 4',6-diamidino-2-phenylindole (DAPI) staining and Western blot analysis, respectively. The flow cytometric analysis of H-ALA (5μM) uptake revealed optimal fluorescent intensity at 8h incubation, while ALA (0.5mM) was still far from saturation. The LD(30) of H-ALA-PDT was 30μM, 2J/cm(2), while the LD(30) of ALA-PDT was 3mM, 2J/cm(2). The dark toxicities mediated by both pro-drug H-ALA and ALA were negligible. By DAPI staining, apoptotic cell death was observed. In addition, by Western blot analysis, H-ALA- and ALA-mediated PDT initiated apoptotic cell death via the up-regulation and activation of p38 mitogen activated protein kinase (MAPK), the stress-activated c-jun N-terminal kinases (JNK) and ERK. These results suggested that H-ALA and ALA mediated PDT displayed similar photocytotoxicities towards the two non-small lung cancer cells. Our present study also demonstrates H-ALA or ALA mediated PDT in H460 cells are closely related to the activation of p38 MAPK and JNK signalling pathway.
There are proteins, responsible for many basic cell functions (transmission of extracellular signals to cytoplasm or nucleus, cell growth, proliferation, migration, survival), which are activated and overexpressed in response to acute oxidative stress, especially tyrosine kinases. The oxidative stress-associated Src activator/Homo sapiens chromosome 9 open reading frame 10 protein (Ossa/C9orf10) protects cancer cells from oxidative stress-induced apoptosis by Src family kinases activation. In this study precursor of protoporphyrin IX, 5-aminolevulinic acid and its encapsulated form were used in treating MCF-7 human breast cancer cells. After light illumination, cells were collected at different time points and used for evaluation (immunocytochemistry, Western blot analysis) of expression of above proteins, c-Src and Ossa. Our results showed that 5-aminolevulinic acid-mediated photodynamic therapy caused decrease of c-Src expression at 7hours after irradiation. The strongest expression was observed at 24hours after treatment. Encapsulated form of 5-aminolevulinic acid in terms of PDT caused similar changes of expression of c-Src protein. Furthermore, we observed strong Ossa expression at 7hours after treatment in comparison to very low expression at time points 0, 18 and 24hours. We would like to emphasize that our results showed high expression of Ossa at early time interval after PDT, which was accompanied by a low expression of c-Src kinase, what could protect cancer cells from PDT through activation of c-Src in response to oxidative stress.
Cystoid macular edema is a common retinal disorder with the potential for significant vision-related morbidity, and intravitreal lucentis® injection is confirmed to be an effective therapy approach. In the present study, we investigated the discrepancy between central foveal thickness and best corrected visual acuity in such lesions and infered that intravitreal lucentis® injection may help the visual function, related to the renewal of cells.
Introduction: PDT is a safe procedure with most post procedural complications reported as minor. We report a case of severe acute stridor and trachea-bronchial airway obstruction with mucosal sloughing and fibrous plugs resulting in respiratory failure within three hours following PDT. To our knowledge this is the first reported case where stridor and acute respiratory failure resulted within hours following PDT treatment. Case report: A 65 year old female with previous right pneumonectomy presented with followup bronchoscopy confirming reoccurrence of carcinoma proximal and distal to the anastomosis. A standard photofrin (Porfimer sodium) was administered at 2mg/kg body weight 48 hours prior to her PDT treatment. Three hours following the procedure, patient become acutely stridurous and was subsequently intubated. Bedside bronchoscopy was performed through the endotracheal tube. During the bronchoscopy thick tracheal plugs were retrieved and slough adjacent to the treatment site was noticed which was debrided. Patient underwent 7 bronchoscopies with debridement before she was discharged. Conclusion: Airway obstruction (with NSCLA) is an indication as well as complication (with mucosal debris) of PDT. FDA has advised bronchoscopy at 48-72 hours post procedure, however early intervention with bronchoscopy and debridement should be considered to relieve tracheal bronchial airway obstruction and removal of accessory debris and mucosal slough.
We report two cases of acute urinary retention (AUR) occurred after intra-urethral aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) in elderly females (>66 years old) with urethral condylomas.
In a previous study it is shown that for topically applied ALA-PDT, PpIX concentration correlates with vascular changes including vasoconstriction and/or vascular leakage of small vessels and arterioles in the mouse epidermis and dermis. In this study we report on vascular responses induced by ALA-PDT for different fluence rates, including both changes in vessel diameter and dynamics in RBC velocity in arterioles, imaged using intra-vital confocal microscopy in skinfold chambers in hairless mice. Our interest is in the dynamics of vascular changes in the early stages of illumination. We have determined the total PDT dose to be relatively low, 13Jcm(-2), and fluence rates of 26, 65 and 130 mW cm(-2) were investigated. Local vascular effects occurred very soon after the start of the therapeutic illumination in ALA-PDT. In this study, we did not find a significant difference between fluence rates. Arterioles were particularly sensitive to vasoconstriction during low dose PDT, often resulting in complete vasoconstriction. When we observed complete vasoconstriction, this coincided with changes in RBC velocity. Since the therapeutic effects of PDT are dependent on a fine balance between the need for oxygen during illumination and disruption of the vasculature, the results of the present study add to our understanding of acute vascular effects during ALA-PDT and aid our efforts to optimize PDT using porphyrin pre-cursors.
A case of adenocarcinoma in the pharyngo oesophageal junction extending to the upper cervical oesophagus is described. In this case the neo-plastic changes had occurred from columnar epithelium of gastric and intestinal type: Barrett's oesophagus. The Barrett's mucosa involved the whole length of the oesophagus. Because of the general condition of the patient and advanced stage of the tumour surgical treatment was considered inappropriate. Endoscopic Photofrin Photodynamic Therapy was used with good palliation of dysphagia. The patient survived for 9 months, dying form carcinomatosis and oesophago-airway fistula. As far as can be documented only one such case has been previously reported in the literature.
Background: Photodynamic therapy (PDT) is used for the treatment of many types of predominantly epithelial cancers. Photosensitizer is taken up by fast growing tumor cells more actively than by other body cells and is activated by light, generating reactive oxygen species that cause cell death by necrosis or apoptosis. This study aimed to evaluate the efficacy of PDT with indocyanine green (ICG) through the investigation of TP53, HER-2 and TOP2A genes signals as breast cancer gene markers by interphase fluorescence in situ hybridization (nuc-FISH). Methods: The photosynthetizer ICG (200 μM) was applied to breast cancer cell line MCF-7 cells (adenocarcinoma) in combination with laser irradiation (807 nm) exposure for 20 min and then incubated for 12, 24 and 48 h. Cell viability was evaluated using trypan blue. The signals for nuc-FISH was investigated and counted for probes specific for the genes TP53 (17p13), HER-2 (17q11.2-q12), and TOP2A (17q21-q22), and BAC-probes RP11-746M1 in 17p11.2 and RP11-403E9 in 17q11.2. Results: The cell viability of MCF-7 did not reduced significantly when the cells were treated with ICG (200 μM) or exposed to laser irradiation for 20 min followed by incubation for 24 h. ICG/PDT treatment with laser irradiation exposure for 20 min reduced the cell viability after incubating cells for 12, 24 and 48 h highly significantly in a time dependent manner. For nuc-FISH analysis, TP53, HER-2, TOP2A, RP11-746M1 and RP11-403E9 signals did not reduce or increase in a significant manner when the cells were treated with ICG or exposed to laser irradiation for 20 min then incubated for 24h. PDT enhanced amplification of TP53 signals from nuc ish 17p13(TP53×2) to nuc ish 17p13(TP53×3) or nuc ish 17p13(TP53×4). However, the signals of HER-2 gene, TOP2A gene and BAC probes were reduced highly significantly when MCF-7 cells were treated with PDT with all time intervals. Conclusion: ICG/PDT and laser induced cytotoxic effect in MCF-7 cells. Also, PDT enhanced TP53 gene amplification, and reduced HER-2, TOP2A, and BAC probes RP11-746M1 and RP11-403E9 signals. Therefore ICG/PDT can be used for breast cancer treatment. It has the potential to induce apoptotic effect and reduce HER-2 and TOP2A genes propagation. Further in vivo studies are needed to evaluate ICG/PDT as a promising therapeutic approach for breast cancer.
Top-cited authors
Michael Hamblin
  • University of Johannesburg
Ana Castano
  • Massachusetts General Hospital
Ron R Allison
Xin Hu
  • East Carolina University
Fahim Vohra
  • King Saud University