Aminolevulinic Acid-based Photodynamic Therapy Research Articles

Comparison of blue laser and red light-emitting diode-mediated aminolevulinic acid-based photodynamic therapy for moderate and severe acne vulgaris: A prospective, split-face, nonrandomized controlled study

BackgroundAcne is a chronic inflammatory skin disease. Photodynamic therapy (PDT) is a highly effective and safe drug-device combination treatment, typically using red and blue light. However, direct comparisons of aminolevulinic acid (ALA)-based PDT using these two light sources are lacking. Therefore, we compared the efficacy and adverse effects of ALA-based 450 nm blue laser-mediated PDT (BL-PDT) and 630 ± 10 nm red light-emitting diode-mediated PDT (RL-PDT) in the treatment of moderate-to-severe acne vulgaris, including analyses of different lesion types. MethodsSixteen patients with moderate-to-severe acne vulgaris were recruited. All patients underwent BL-PDT on the left side of the face and RL-PDT on the right side. Treatments were administered thrice at 2-week intervals, and follow-up continued for 2 weeks after the final treatment. The average rates of improvement in inflammatory and non-inflammatory acne lesions, IGA (Investigator's Global Assessment) scales, and IGA success rates were calculated. In addition, adverse effects during and after each treatment were recorded. ResultsAt the 2-week follow-up after the final treatment, the average rates of improvement in total acne, inflammatory, and non-inflammatory lesions were 48.0 %, 63.0 %, and 30.0 % in the BL-PDT group and 42.2 %, 58.1 %, and 27.5 % in the RL-PDT group, respectively. The IGA scores for the two groups decreased by 1.8 and 1.7 points, respectively, and the IGA success rate was 53.3 % in both groups. There were no significant differences between the BL-PDT and RL-PDT groups in any measure of effectiveness. However, the BL-PDT group exhibited more severe adverse effects, especially pain and hyperpigmentation. ConclusionsBL-PDT and RL-PDT have similar efficacies in moderate-to-severe acne vulgaris and are particularly effective for inflammatory acne lesions. RL-PDT benefits from milder adverse effects than those of BL-PDT.

Modifications of DAMPs levels in extracellular environment induced by aminolevulinic acid-based photodynamic therapy of esophageal cancer cells

Purpose Immunogenic cell death plays an important role in anticancer treatment because it combines cell death with appearance of damage associated molecular patterns that have the potential to activate anticancer immunity. Effects of damage associated molecular patterns induced by aminolevulinic acid-based photodynamic therapy were studied mainly on dendritic cells. They have not been deeply studied on macrophages that constitute the essential component of the tumor microenvironment. The aim of this study was to analyze features of esophageal cancer cell death in relation to release capacity of damage associated molecular pattern species, and to test the effect of related extracellular environmental alterations on macrophages. Material and methods Esophageal Kyse 450 carcinoma cells were subjected to aminolevulinic acid-based photodynamic therapy at different concentrations of aminolevulinic acid. Resting, IFN/LPS and IL-4 macrophage subtypes were prepared from monocytic THP-1 cell line. Cell death features and macrophage modifications were analyzed by fluorescence-based live cell imaging. ATP and HMGB1 levels in cell culture media were determined by ELISA assays. The presence of lipid peroxidation products in culture media was assessed by spectrophotometric detection of thiobarbituric acid reactive substances. Results Aminolevulinic acid-based photodynamic therapy induced various death pathways in Kyse 450 cells that included features of apoptosis, necrosis and ferroptosis. ATP amounts in extracellular environment of treated Kyse 450 cells increased with increasing aminolevulinic acid concentration. Levels of HMGB1, detectable by ELISA assay in culture media, were decreased after the treatment. Aminolevulinic acid-based photodynamic therapy induced lipid peroxidation of cellular structures and increased levels of extracellular lipid peroxidation products. Incubation of resting and IL-4 macrophages in conditioned medium from Kyse 450 cells treated by aminolevulinic acid-based photodynamic therapy induced morphological changes in macrophages, however, comparable alterations were induced also by conditioned medium from untreated cancer cells. Conclusion Aminolevulinic acid-based photodynamic therapy leads to alterations in local extracellular levels of damage associated molecular patterns, however, comprehensive studies are needed to find whether they can be responsible for macrophage phenotype modifications.

Expert consensus on the clinical application of aminolevulinic acid-based photodynamic therapy for acne vulgaris (2022)#

Aminolevulinic acid-based photodynamic therapy (ALA⁃PDT) is a safe and effective physical therapy for acne vulgaris that is widely used in clinical practice. To further standardize the clinical application of ALA⁃PDT in the treatment of acne, we created this updated consensus based on the 2011 version of the consensus on ALA⁃PDT for the treatment of acne vulgaris. In this document, we summarize the mechanisms of action of ALA-PDT and provide practical standards for patient selection, treatment parameters, administration procedures, and management of adverse reactions. Our aim was to provide guidance and treatment regimens for using ALA-PDT for acne vulgaris in clinical practice.

ALA-PDT combined with oral acitretin in the treatment of refractory condyloma acuminatum in anal canal

BackgroundCondyloma acuminatum (CA) of the anal canal is difficult to treat and subject to relapse.. We investigated the effects of aminolevulinic acid-based photodynamic therapy (ALA-PDT) combined with oral acitretin during therapy of refractory CA in the anal canal. We also conducted a clinical retrospective study for the treatment of intra-anal CA. MethodsA total of 101 patients diagnosed with intra-anal CA were enrolled. All patients underwent liquid nitrogen cryotherapy as a basic treatment until visible wart clearance. Patients were divided into two groups depending on the treatment modality after cryotherapy. ALA-PDT group with 51 patients was given ALA-PDT treatment, and ALA-PDT plus acitretin group with 50 patients was given ALA-PDT treatment combined with oral acitretin. The cure rate, recurrence rate, and adverse reactions of the two groups were analyzed and recorded. ResultsThe cure rate in the ALA-PDT plus acitretin group was 94% (47/50), which was significantly higher than 80.4% (41/51) in ALA-PDT group. The recurrence rate in the ALA-PDT plus acitretin group was 6% (3/50), which was lower than 19.6% (10/51) in ALA-PDT group (P<0.05). ConclusionALA-PDT combined with oral acitretin is effective and safe in the treatment of refractory CA in anal canal, and with further study may become an option for these patients.

Suppression of resistance to aminolevulinic acid-based photodynamic therapy in esophageal cell lines by administration of iron chelators in collagen type I matrices

Purpose Photodynamic therapy (PDT) utilizes visible light to activate the cytotoxic effects of photosensitizing drugs. PDT protocols require optimization to overcome treatment resistance and induce a beneficial anti-tumor immune response. The aim of this study was to examine the possibility to suppress the resistance of esophageal cell lines to aminolevulinic acid (ALA)-PDT by administration of iron chelators to induce sufficient cell cytotoxicity under pathophysiologically relevant conditions, mimicking the advanced stages of cancer. Materials and methods Effects of ALA-PDT in combination with iron chelators were compared in three esophageal cell lines in conventional monolayers and in 3 D cultures based on collagen type I. Modified colony assay and fluorescence-based live cell imaging, respectively were applied. The latter was used also to test the capability of pre-polarized macrophages to interact with cancer cells subjected to ALA-PDT with or without iron chelators. Results Iron chelators were effective in the enhancement of ALA-PDT in all cell lines under both culture conditions. Fluorescence evaluation of cell viability in 3 D cultures indicated the contribution of apoptotic cell death after ALA-PDT, both with and without iron chelators. Engulfment of remnants of dead cancer cells by macrophages in 2 D cultures was indicated, however, the interaction between macrophages and cancer cells in 3 D cultures subjected to ALA-PDT with or without iron chelators was not present. Conclusions The potential of iron chelators to enhance ALA-PDT was maintained in 3 D collagen matrices. Although PDT dose (ALA concentration, light exposure time) required modification in a cell line-dependent manner to achieve a comparable effect of PDT alone in conventional monolayers and in collagen matrices, the potential of iron chelators to suppress the resistance of esophageal cells to ALA-PDT was not influenced by a fibrillar collagen matrix.

氨基酮戊酸光动力成功治疗合并再生障碍性贫血的重度痤疮一例

氨基酮戊酸光动力成功治疗合并再生障碍性贫血的重度痤疮一例

Modulation of aminolevulinic acid-based photoinactivation efficacy by iron in vitro is cell type dependent

Iron availability to cells may be modified in the tumour microenvironment, which may be involved in treatment response. Iron availability affects the conversion of protoporphyrin IX to heme, which likely determines the efficacy of aminolevulinic acid-based photodynamic therapy (ALA-based PDT). We compared photoinactivation efficacy in three oesophageal cell lines in culture media differing in iron content, DMEM and RPMI 1640, and in RPMI 1640 supplemented with iron to understand the importance of iron presence for ALA-based PDT outcome. ALA-based PDT was more efficacious in DMEM than in RPMI 1640 in all tested cell lines. Consistently, the highest protoporphyrin IX fluorescence signals, indicating the highest level of protoporphyrin IX production, were detected from cell colonies incubated in DMEM compared to those incubated in RPMI 1640 irrespective of iron presence. Components in the culture media other than iron ions are likely to be responsible for the observed differences in two culture media. Nevertheless, iron supplementation to RPMI 1640 showed that the presence of ferric ions in the concentration range 0–8 mg/l affected ALA-based PDT efficacy in a cell type-dependent manner. In poorly differentiated carcinoma cells, the increased efficacy of ALA-induced photoinactivation in the presence of 0.1 mg/l of supplemented iron was found. At the same iron concentration, the slightly different mitochondrial potential at no modifications of the iron labile pool was observed. The efficacy of ALA-based PDT in vitro depends on the choice of culture medium and the presence of iron ions in culture medium depending on intrinsic properties of cells.

Fundamentals of 5‐aminolevulinic acid photodynamic therapy and diagnosis: An overview

Abstract5‐Aminolevulinic acid‐based photodynamic therapy (ALA‐PDT) comprises photochemical and biological reactions, finally generating tumor destruction. Tumor selectivity of ALA‐PDT relies on the disturbed heme synthesis pathway in neoplastic cells. Tumor pretreatment with ALA induces two reactions: the first, self‐activation of the key enzyme porphobilinogen synthase and then protoporphyrin (PpIX) synthesis at low Fe++ availability. We emphasize that the toxic mechanism of ALA‐PDT triggered by 1O2 targets intracellular organelle destruction death pathways. PpIX fluorescence of tumors, particularly in glioblastoma, is used clinically for fluorescence guidance during neurosurgery. Targeting residual and metastatic cancer stem cells is a crucial challenge of ALA‐PDT, plausibly combined with other therapeutic modalities to encounter metastatic recurrences. We overview the different aspects of ALA‐PDT mechanism and future research and prospects.

氨基酮戊酸-光动力疗法对尖锐湿疣组织中血管内皮生长因子和增殖细胞核抗原表达的影响

Objective To evaluate the effect of aminolevulinic acid-based photodynamic therapy (ALA-PDT) on the expression of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) in condyloma acuminatum (CA) tissues. Methods A total of 56 patients with CA were enrolled from Department of Dermatology, The First Affiliated Hospital of Zhengzhou University from October 2016 to September 2017, and skin lesions were obtained before and 1 week after the first ALA-PDT treatment. Immunohistochemical SP method was used to determine the expression of VEGF and PCNA in keratinocytes in the CA tissues. Chi-square test and rank sum test were carried out to analyze differences between pre- and post-treatment expression rate and intensity of VEGF and PCNA, and Spearman correlation analysis was conducted to analyze the correlations between the protein expression of VEGF and PCNA. Results The expression rates of VEGF and PCNA in keratinocytes in the CA tissues were 71.43% (40/56) and 73.21% (41/56) respectively before ALA-PDT, and 44.64% (25/56) and 41.07% (23/46) respectively after ALA-PDT. There were significant differences between pre- and post-treatment expression rate and intensity of VEGF and PCNA (expression rate: χ2 = 8.25, 11.81 respectively, both P < 0.05; expression intensity: H = 11.29, 12.22 respectively, both P < 0.05) . The expression of VEGF was positively correlated with the expression of PCNA in the CA tissues before and after the ALA-PDT treatment (rs = 0.202, 0.273, respectively, both P < 0.05) . Conclusion The expression of VEGF and PCNA decreased in CA tissues after ALA-PDT treatment, which may be one of the mechanisms underlying the treatment of CA with ALA-PDT. Key words: Condylomata acuminata; Photochemotherapy; Aminolevulinic acid; Vascular endothelial growth factors; Proliferating cell nuclear antigen

Novel strategy to increase specificity of ALA-Induced PpIX accumulation through inhibition of transporters involved in ALA uptake.

Aminolevulinic acid-based photodynamic therapy (ALA-PDT) has emerged as a cancer treatment due to its high specificity and low side effects. In this study, we aimed to identify possible new drugs targeting transporters highly expressed in normal cells but not in cancer cells, to increase the specificity of ALA-PDT. We used a total of seven cell lines, consisting of two gastric, three prostate, and two lung cell lines, for this purpose. siRNAs and inhibitors of these transporters were added, and PpIX production was evaluated using HPLC to examine the roles of transporters in ALA uptake. No correlation in the expression of transporters was observed among cell lines of the same origin. Two major findings were obtained: PEPT1 and PAT1 were expressed only in normal lung and prostate cells, respectively, but not in their cancerous counterparts. The inhibition of these transporters saw a significant decrease in PpIX production only in normal cells, but not in cancer cells. These findings show that the usage of drugs targeted specifically to highly expressed transporters in normal cells is essential for reducing PpIX accumulation in normal cells in order to increase the specificity of ALA-PDT in cancer.

Painless versus conventional photodynamic therapy for treatment of actinic keratosis: Comparison of cell death and immune response in a murine model.

Aminolevulinic acid based photodynamic therapy (ALA-PDT) is a popular and efficacious treatment for actinic keratosis (AK). However, standard PDT can elicit stinging pain during illumination, and hence is not always favored by patients. In a new regimen called metronomic PDT (mPDT), similar to daylight PDT but using blue light, the illumination is delivered concurrently with ALA application rather than after a 1-hour pre-incubation (conventional regimen, cPDT). In the clinic, mPDT is not only painless but also nearly as effective as cPDT for AK lesion clearance. In this investigation, a murine AK model (generated by repeated UVB exposure) was treated with either mPDT or cPDT. Lesion clearance was followed by area measurement, and samples were harvested for mechanistic analyses. Compared to pretreatment (100%), the average lesion area was reduced to 47% and 32% in cPDT, and to 57% and 40% in mPDT at 1- and 2-weeks post PDT, respectively. Relative to untreated controls, enhanced cell death (histomorphology by H&E staining and apoptosis by TUNEL assay), and generation of Reactive Oxygen Species (ROS; CM-H2DCFDA staining) were observed in both cPDT and mPDT samples. Activation of cleaved Caspase-3 was specifically observed only in cPDT samples. Immunomodulation by inflammatory cells was observed by enhanced infiltration/retention of neutrophils and macrophages in metronomic PDT samples. Our results suggest that metronomic PDT can be just as effective as conventional PDT for treatment of AK, but the mechanisms may be quite different.

Effects of aminolevulinic acid-based photodynamic therapy on the Toll-like receptor 2 signaling pathway in the murine macrophage line RAW264.7

Objective To evaluate the effect of aminolevulinic acid-based photodynamic therapy (ALA-PDT) on the expression of Toll-like receptor 2 (TLR2) and downstream signaling pathway molecules, and secretion of cytokines in murine RAW264.7 cells. Methods The RAW264.7 murine macrophages were induced by inactivated Propionibacterium acnes suspension for the establishment of a cell model of inflammation. The cultured RAW264.7 cells were divided into 5 groups: blank control group receiving normal culture followed by the treatment with phosphate buffer saline (PBS) , model group treated with inactivated Propionibacterium acnes suspension followed by the treatment with PBS, and three ALA groups treated with inactivated Propionibacterium acnes suspension followed by the treatment with 0.03, 0.06 and 0.12 mmol/L ALA, respectively, and infrared radiation at a dose of 16 J/cm2. Enzyme-linked immunosorbent assay (ELISA) was performed to detect levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the culture supernatant of RAW264.7 cells, and Western blot analysis to determine the protein expression of TLR2 and myeloid differentiation factor 88 (MyD88) , as well as p38, c-Jun N-terminal kinase (JNK) , extracellular signal-regulated kinase (ERK) , inhibitor of κB kinase α (IκBα) and their phosphorylated forms (p-p38, p-JNK, p-ERK and p-IκBα) . Results Compared with the blank control group, the model group showed significantly higher levels of TNF-α ([0.34 ± 0.02]ng/L, P 0.05) , but a significantly lower level of IL-6 ([0.07 ± 0.01]ng/L, F= 114.813, P < 0.01) . The protein expression of TLR2, MyD88, p-p38, p-IκBα, p-JNK and p-ERK was all significantly higher in the model group (0.90 ± 0.14, 1.11 ± 0.13, 0.84 ± 0.04, 1.45 ± 0.20, 2.56 ± 0.06, 3.70 ± 0.40) than in the blank control group (all P < 0.01) , and gradually decreased along with the increase of ALA concentration in a dose-dependent manner. Conclusion Photodynamic therapy can suppress the expression of TLR2 in RAW264.7 murine macrophages, and decrease the secretion of cytokines likely by the TLR2 signaling pathway. Key words: Propionibacterium acnes; Acne vulgaris; Aminolevulinic acid; Photochemotherapy; Toll-like receptor 2; Signal transduction

Effect of aminolevulinic acid-based photodynamic therapy on the expression of protein kinase D1 and its phosphorylation sites in a cutaneous squamous cell carcinoma cell line A431

Objective To evaluate the effect of aminolevulinic acid-based photodynamic therapy (ALA-PDT) on the expression of protein kinase D1 (PKD1) in a cutaneous squamous cell carcinoma cell line A431, and to explore the mechanism underlying ALA-PDT-induced apoptosis of A431 cells. Methods A431 cells were cultured in vitro, and cell counting kit-8 (CCK-8) assay was performed to select the optimal combination of ALA concentration and PDT dose with the strongest proliferation inhibitory effect. A431 cells at exponential growth phase were randomly divided into 4 groups: control group receiving no treatment, ALA group treated with ALA solution alone, PDT group treated with PDT alone, and ALA-PDT group treated firstly with ALA solution and then with PDT. After 12-, 24-, 36- and 48-hour additional culture, CCK-8 assay was conducted to evaluate the cellular proliferation inhibition, and the apoptosis rate at the time point of the strongest proliferation inhibitory effect was measured by flow cytometry. RT-PCR was performed to determine the expression of protein kinase D1 gene (PRKD1) in A431 cells at different time points after the ALA-PDT treatment, and Western blot analysis to measure protein expression of PKD1 and its phosphorylation at Tyr463 (pTyr463) and Ser916 (pSer916) in A431 cells. Results The combi-nation of ALA at the concentration of 1.5 mmol/L with PDT at an irradiation dose of 2 J/cm2 was optimal due to its strongest proliferation inhibitory effect. After 12-, 24-, 36- and 48-hour additional culture, there were significant differences in the proliferation inhibition rate among the 4 groups (F= 39.56, P 0.05) . No significant difference in the Ser916-phosphorylated PKD1 expression was found among the 4 groups (F= 1.53, P > 0.05) , while there were significant differences in the expression of PKD1 and Tyr463-phosphorylated PKD1 among the 4 groups (F= 10.04, 8.27, both P < 0.05) . Additionally, the ALA-PDT group showed significantly lower expression of PKD1 and Tyr463-phosphorylated PKD1 compared with the control group, ALA group and PDT group (all P < 0.05) . Conclusion PKD1 may be involved in the photochemical process of A431 cell apoptosis induced by ALA-PDT, and may promote the occurrence of squamous cell carcinoma by Tyr463 phosphorylation. Key words: Photochemotherapy; Aminolevulinic acid; Neoplasms, Squamous Cell; Protein kinases; Primary cell culture; A431 cell

The use of animal models in researches on aminolevulinic acid-based photodynamic therapy for the treatment of skin diseases

Aminolevulinic acid-based photodynamic therapy (ALA-PDT) , a kind of non-invasive and effective treatment strategy with less adverse effects, has been widely applied in the treatment of various diseases in dermatology. Animal models are an important means to assess therapeutic effects and mechanisms of ALA-PDT. In recent years, the use of animal models for skin neoplasms, photoaging, acne, scar and psoriasis have optimized treatment parameters of ALA-PDT, further clarified therapeutic mechanisms of ALA-PDT, and provided theoretical basis for the development and application of sensitizers in ALA-PDT. Key words: Skin diseases; Aminolevulinic acid; Photochemotherapy; Models, animal; Mice; Rabbits

Photodynamic therapy for the treatment of 18 cases of skin tumors

Objective To evaluate the efficacy of photodynamic therapy in the treatment of skin tumors unsuitable for surgery. Methods Totally, 8 cases of actinic keratosis (AK) , 6 cases of squamous cell carcinoma (SCC) , 3 cases of Bowen's disease, and 1 case of basal cell carcinoma (BCC) were treated with aminolevulinic acid-based photodynamic therapy. Aminolevulinic acid 20% solution was prepared, and applied to skin lesions. After 4-6 hours, the lesions were irradiated with red light at an energy density of 80 to 100 J/cm2 for 20 minutes. Totally, 3 to 6 sessions of photodynamic therapy were given at a frequency of once a week. The therapeutic effect was evaluated at the end of the course of treatment. Results Eight patients with AK, 4 SCC and 3 Bowen's disease achieved complete remission, and another 2 patients with SCC and 1 BCC achieved partial remission. No recurrence was observed in any of the 18 patients at 1, 2, 3 and 6 months after the end of treatment. Conclusion Aminolevulinic acid-based photodynamic therapy is a kind of non-invasive approach to the treatment of skin tumors unsuitable for surgery with no risk of obvious scar formation. Key words: Skin neoplasms; Photochemotherapy; Treatment outcome; Aminolevulinic acid; Surgical procedures, elective

Surgical operation combined with aminolevulinic acid-based photodynamic therapy for the treatment of giant condyloma acuminatum: 12 case reports

Objective To evaluate the clinical efficacy of surgical operation combined with aminolevulinic acid-based photodynamic therapy (ALA-PDT) for the treatment of giant condyloma acuminatum. Methods Totally, 12 patients with giant condyloma acuminatum of the external genitalia and/or perianal region were enrolled, including 7 males and 5 females. Firstly, the warts were removed by surgical operation and bipolar electrocoagulation cautery. After wound healed, ALA-PDT was carried out at the lesional sites once every 7-10 days for 2-4 sessions. Results Within 6 months of follow-up, warts completely disappeared, and the acetowhitening test turned negative in all the 12 patients. Mild erythematous swelling occurred with pain and burning sensation after the operation, but no other adverse reactions such as infection, ulcer, or obvious scarring were observed. Conclusion Surgical operation combined with ALA-PDT is a relatively good choice for the treatment of condyloma acuminatum. Key words: Condylomata acuminata; Photochemotherapy; Aminolevulinic acid; Surgical procedures, operative; Clinical protocols

Effects of photodynamic therapy on the proliferation and apoptosis of human papillomavirus type 16 E7 protein-expressing HaCaT cells

Objective To explore the effects of aminolevulinic acid-based photodynamic therapy (ALA-PDT) on the proliferation and apoptosis of HaCaT cells stably expressing human papillomavirus type 16 E7 protein (HaCaT/HPVl6 E7 cells) . Methods Cultured HaCaT/HPV16 E7 cells were divided into several groups: blank control group receiving no treatment, ALA group treated with ALA alone, irradiation group irradiated with 630-nm red laser (30 mW/cm2, 12 J/cm2) , ALA-PDT groups pretreated with ALA for 5 hours followed by 630-nm red laser radiation at 4, 8, 12 J/cm2 respectively. CCK8 assay was performed to determine the survival rate of cells at 24 hours after PDT, and flow cytometry and confocal microscopy were conducted to detect cell apoptosis and observe cell morphology respectively at 3 hours. Results At 24 hours, the survival rate of cells was 68.98% ± 1.03%, 46.03% ± 2.96% and 23.57% ± 3.83% in the 4-, 8- and 12-J/cm2 ALA-PDT groups respectively, significantly lower than that in the blank control group, ALA group and irradiation group (99.15% ± 0.64%, 98.13% ± 0.83% and 96.85% ± 1.37% respectively, all P< 0. 05). With the increase in radiation dose, cell apoptosis was accelerated with obvious morphological changes and shrinkage of cells in the ALA-PDT groups. Conclusion ALA-PDT can inhibit the proliferation, and promote the apoptosis of HPV-infected HaCaT cells in a dose-dependent manner within a certain range of radiation dose. Key words: Aminolevulinic acid; Photochemotherapy; Cell proliferation; Apoptosis; Alphapapillomavirus; HPV16 E7

Effects of aminolevulinic acid-based photodynamic therapy on chicken combs, an animal model for port wine stains

Objective To investigate the effects of aminolevulinic acid-based photodynamic therapy (ALA-PDT) on chicken combs, an animal model for port wine stains (PWS), and to explore the feasibility of PWS treatment with ALA-PDT. Methods A total of 80 leghorns were randomly and equally divided into 10 groups: blank control group receiving no treatment, ALA group treated with ALA alone, four single laser groups irradiated with 630-nm red laser at 75, 100, 150 and 200 J/cm2 respectively, four ALA-PDT groups pretreated with ALA followed by 630-nm red laser radiation at 75, 100, 150 and 200 J/cm2 respectively. An area sized 1 cm×1 cm were marked at one side of combs in all these leghorns, and served as the experiment area to receive corresponding treatment, with that in the other side as the control area. Tissue specimens were obtained on the 14th and 28th days after treatment followed by the observation of morphological and histological changes, calculation of decrement rate in capillary number, and determination of apoptosis index in vascular endothelial cells (VECs) in chicken combs. Results In all the four ALA-PDT groups, the combs became lighter in color with apoptosis of some VECs as well as a decrease in capillary count and diameter in the dermis of the experiment areas. The decrement rate in capillary number was 33.53%±4.89%, 52.02%±2.77%, 67.48%±5.58% and 88.96%±2.47% respectively, and apoptosis index in VECs was 63.44±1.09, 88.50±6.11, 94.32±3.67 and 113.76±10.57 respectively, in the 75-, 100-, 150- and 200-J/cm2 ALA-PDT groups on the 14th day after treatment, and both the decrement rate and apoptosis index in each of these groups were significantly different from those in the blank control group, ALA group, single laser groups receiving red laser radiation at the corresponding dose, and the other ALA-PDT groups (all P<0.01) separately. The apoptosis depth of VECs, defined as the vertical distance from the basal layer to the deepest level at which VEC apoptosis occurred, was 201.19±0.33 μm, 266.15±1.02 μm, 546.09±2.45 μm and 766.37±1.08 μm respectively in the 75-, 100-, 150- and 200-J/cm2 ALA-PDT groups on the 14th day, with significant differences between these four groups (all P<0.01). Conclusions ALA-PDT can markedly damage capillaries in the animal model of port wine stains, chicken combs, with the degree and depth of capillary damage associated with red light energy density. The induction of VEC apoptosis may be an action mechanism of ALA-PDT in the treatment of PWS. Key words: Port-wine stain; Aminolevulinic acid; Photochemotherapy; Apoptosis; Models, animal; Chicken comb

Dermabrasion combined with aminolevulinic acid-based photodynamic therapy for the treatment of nasal nodular basal cell carcinoma: 25 case reports

Objective To investigate the efficacy of dermabrasion combined with aminolevulinic acid-based photodynamic therapy (ALA-PDT) for the treatment of nasal nodular basal cell carcinoma (nBCC). Methods Twenty-five patients who were pathologically diagnosed as nasal nBCC with lesion area>1 cm2 but no bone or cartilage involvement, were included in this study and treated with dermabrasion combined with ALA-PDT. At first, the part of tumor protruding outside the skin was removed by artherectomy, then dermabrasion was carried out. The wound surface was topically treated with 20% aminolevulinic acid solution for 3- 4 hours away from light immediately after surgery, then irradiated with LED light at a mean dose of 100 J/cm2 for 20 minutes. ALA-PDT was performed once a week for 3 consecutive weeks. The degree of and time required for wound healing were assessed, and tumor recurrence, cicatrization and appearance outcomes were observed during 1 year after surgery. Efficacy was assessed comprehensively. Results No postoperative wound infection occurred in these patients, and the average time for wound healing was (11.2±1.3) days. During 1 year after the treatment, no recurrence was found, while cicatricial contracture developed in 1 case, mild proliferative scar in 3 cases, and depressed scar in 4 cases. All the patients were satisfied with the treatment outcomes, except 1 patient who was basically satisfied. Conclusions Dermabrasion combined with ALA-PDT is easy to operate with rapid wound healing, low postoperative recurrence rate and high degree of patient satisfaction, and is worthy of clinical promotion. Key words: Carcinoma, basal cell; Dermabrasion; Aminolevulinic acid; Photochemotherapy

Aminolevulinic acid-based photodynamic therapy induces apoptosis of prematurely senescent fibroblasts induced by ultraviolet B stress

Objective To study the effect of aminolevulinic acid-based photodynamic therapy (ALA-PDT) on oxidative damage to and apoptosis of prematurely senescent fibroblasts induced by ultraviolet B stress (UVB-SIPS-FB). Methods Both normal fibroblasts and UVB-SIPS-FB were divided into 2-hour and 6-hour groups with the duration of incubation with ALA away from light being 2 and 6 hours respectively, and each group was divided into 7 subgroups: control subgroup receiving no treatment, ALA subgroup treated with ALA alone, red laser group treated with 100 J/cm2 red laser alone, 3 ALA-PDT subgroups pretreated with ALA followed by red laser radiation at 25, 50 and 100 J/cm2 respectively, NAC+ALA-PDT subgroup sequentially pretreated with ALA and NAC (5 mmol/L) followed by red laser radiation at 50 J/cm2. The wavelength and power density of red laser was 635 nm and 50 mW/cm2 respectively in this study. Fluorescence microscopy and flow cytometry were performed to determine the levels of reactive oxygen species (ROS) and mitochondrial membrane potentials (MMPs), and Hoechst staining and flow cytometry to detect cell apoptosis. Statistical analysis was carried out with the software SPSS 13.0 by one-way analysis of variance (ANOVA) and q test. Results The apoptosis rate of UVB-SIPS-FB was significantly higher in the 25-, 50-, 100-J/cm2 ALA-PDT subgroups (2-hour group: 7.34%±0.87%, 8.39%±1.16% and 17.03%±1.29% vs. 3.81%±0.59%,F=102.70, P<0.05; 6-hour group: 13.85%±1.71%, 23.40%±2.14% and 41.02%±2.73% vs. 5.09%±1.64%, F=106.00, P<0.05) than in the control subgroups, but lower in the NAC+ALA-PDT subgroups (2-hour group: 5.35%±0.58%, 6-hour group: 9.97%±3.23%, both P<0.05) than in the 50-J/cm2 ALA-PDT subgroups. There was no significant difference in the apoptosis rate of UVB-SIPS-FB between the ALA subgroups or red laser subgroups and control subgroups. ALA-PDT subgroups showed significantly increased ROS level and MMP, and the degree of increase was dependent on the duration of incubation with ALA and dose of red laser, while the pretreatment with the antioxidant NAC could reduce the ALA-PDT induced increase in ROS level and MMP, which was consistent with the changes of apoptosis rate following the treatment. Conclusion ALA-PDT can induce marked apo ptosis of UVB-SIPS-FB, likely through the oxidative damage to cells. Key words: Aminolevulinic acid; Ultraviolet rays; Fibroblasts; Cell aging; Photochemotherapy; Oxidative stress; Apoptosis