5-aminolevulinic Acid-based Photodynamic Therapy Research Articles

Liquid nitrogen cryotherapy effectively and safely improves response of thick Actinic Keratoses lesions by 5-aminolevulinic acid-based photodynamic therapy: a randomized, prospective, single-blind trial

BackgroundActinic keratoses (AK) may progress into squamous cell carcinoma. Many combination therapies were used to improve the clearance rate. However, there are limited studies on the efficacy and safety of lesion-directed Liquid nitrogen cryotherapy combined with field-directed photodynamic therapy (PDT). ObjectiveThis study is aimed to determine the efficacy and safety of Liquid nitrogen cryotherapy combined with PDT in Chinese patients with actinic keratosis. MethodsA total of 61 patients with AK were selected at the Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College between August 2018 and August 2023. They were randomly divided into PDT plus Liquid nitrogen cryotherapy group(LN-PDT)and control PDT group(C-PDT)with 30 patients and 31 patients, respectively. 27 patients in the LN-PDT group and 28 patients in the C-PDT group completed the clinical sessions. Efficacy, adverse effects, and cosmetic outcomes were recorded and compared between the two groups. Results3 months after the final treatment, the clearance rates for total AK lesions were 97.4%(449/461) in the LN-PDT group and 93.4%(456/488)in the C-PDT group (P < 0.05). For grade I AK lesions, the clearance rates were 99.2% (234/237) for the LN-PDT group and 98.3% (237/241) for the C-PDT group (P >0.05). For grade II lesions, the clearance rates were 97.5% (156/160) for the LN-PDT group and 91.9% (172/186) for the CPDT group (P < 0.05). For grade III lesions, the clearance rates of the LN-PDT and C-PDT groups were 87.5% (58/64) and 78.7% (47/61), respectively (P < 0.05). The two groups had no significant differences in pain, erythema, edema, hyperpigmentation and scarring. Cosmetic outcomes mainly were excellent or good in both groups with no significant difference. ConclusionLiquid nitrogen cryotherapy combined with PDT showed higher efficacy on grade II and grade III AK lesions than PDT alone. The two groups have similar adverse effects and cosmetic outcomes.

Studies related to the enhanced the effect of 5-aminolevulinic acid-based photodynamic therapy combined with tirapazamine

Objective5-aminolevulinic acid (5-ALA) is a precursor of the photosensitizer Protoporphyrin IX (PpIX) and photodynamic therapy (PDT) with 5-ALA has been used in clinical practice. However, tumor cellular hypoxia severely affects the efficiency of photodynamic therapy. In this study, photodynamic therapy was combined with tirapazamine to investigate the effects of the combined intervention and the related mechanisms it may involve. MethodsColony formation assays were used to demonstrate cell proliferation. Transwell assays were performed to observe the effect on cell invasion and metastasis after the corresponding intervention. DCFH-DA probe was used to detect the reactive oxygen species content. Flow cytometry was used to detect the effects of the interventions on apoptosis and cell cycle. The relevant pathways that may be involved are explored by examining the expression levels of the relevant proteins and genes. ResultsColony formation assays indicated that the combined intervention inhibited cell proliferation. Transwell assays demonstrated that PDT combined with TPZ effectively inhibited tumor cell invasion and metastasis. In addition, fluorescence intensity generated by DCFH-DA oxidation was detected indicating that the combined intervention increased the formation of reactive oxygen species. Flow cytometry clearly showed that the combination of PDT and TPZ further increased apoptosis and cell cycle arrest. The results of western blotting and qRT-PCR experiments confirmed that the combination therapy inhibited HIF-1α/VEGF axis and the PI3K/Akt/mTOR pathway activation. Conclusion5-ALA-PDT combined with TPZ can inhibit cell proliferation, increase apoptosis, and inhibit the PI3K/Akt/mTOR pathway, thus inhibiting tumor growth and metastasis and improving anti-cancer effects.

Long-term follow-up of photodynamic therapy of cervical intraepithelial neoplasia grade 2 (CIN2)

BackgroundTo determine the long-term efficacy and safety of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) for treating cervical intraepithelial neoplasia grade 2 (CIN2) as well as the suitability of ALA-PDT in treating of cervical lesions divided into cervical transformation zone type 3. MethodsWe included 81 patients diagnosed with CIN2 at the Department of Gynecology of the Affiliated Hospital of Qingdao University with data collected between January 2019 and January 2021 following ALA-PDT. Furthermore, we analyzed the superiority of ALA-PDT in fertility preservation among women of childbearing age based on follow-up data from 11 patients with fertility requirements. ResultsOur findings confirmed the long-term efficacy of ALA-PDT for CIN2 treatment, with an overall efficacy of 95.83 % (23/24) at follow-up of 25–36 months. Moreover, the cervical transformation zone type 3 improvement and human papillomavirus (HPV)-negative efficacy were 69.2 % (18/26) and 82.4 % (14/17), respectively. ALA-PDT is recommended for consenting patients with cervical transformation zone type 3. Additionally, women without primary infertility could experience natural pregnancy and full-term birth of more than one baby following ALA-PDT for CIN2 treatment, with a satisfaction rate of ≈100 %. ConclusionsALA-PDT is recommendable for treating high-grade squamous intraepithelial lesions, especially in patients with fertility requirements.

The efficacy and safety of local 5-aminolevulinic acid-based photodynamic therapy in the treatment of cervical high-grade squamous intraepithelial lesion: a single center retrospective observational study.

Typical treatments for cervical high-grade squamous intraepithelial lesion (HSIL) are invasive procedures. However, these procedures often come with several severe side effects, despite their positive effects on cervical HSIL. 5-aminolevulinic acid photodynamic therapy (ALA-PDT) is a non-invasive treatment that has been successfully used to treat cervical low-grade squamous intraepithelial lesion (LSIL). In this study, we aimed to further investigate the clinical efficacy and safety of ALA-PDT in the treatment of patients with cervical HSIL. A total of 40 patients aged 20 - 41 years with cervical HSIL and high-risk Human Papilloma Virus (HR-HPV) infections were enrolled in this retrospective study from January 2019 to December 2022. Patients were treated with six times of ALA-PDT at intervals of 7-14 days. Three months after the treatment, the efficacy was evaluated through HPV genotyping and cervical cytology examination. If the cytological result was worse than ASC -US, the patient underwent colposcopy-directed biopsy immediately. Otherwise, patients would receive rigorous follow-up observation. Three months after receiving ALA-PDT treatment, 65% (26/40) of cervical HSIL patients at our center showed complete regression (cytological result: normal; HR-HPV: negative). This rate increased to 82.5% (33/40) at the 12-month follow-up. None of the patients experienced disease progression after ALA-PDT therapy. The risk of persistent HR-HPV infection was 32.5% (13/40) at the 3-month follow-up after ALA-PDT. Multivariate analyses identified cervical canal involvement as an independent risk factor for persistent HR-HPV infection at the 3-month follow-up after ALA-PDT treatment. During the treatment of the 40 patients with ALA-PDT, there were no reports of severe adverse reactions. Only a limited number of patients experienced slight discomfort symptoms. ALA-PDT is safe and effective noninvasive therapy for patients with cervical HSIL and HR-HPV infections. It is particularly suitable for young women, who have been confirmed with cervical HSIL and have demand for fertility protection. Three months after ALA-PDT treatment, if a patient still has either ASC-US cervical cytological result and/or HR-HPV infection, rigorous observation is considered safe for her. Cervical canal involvement is an independent risk factor for persistent HR-HPV infection at the 3-month follow-up after ALA-PDT treatment.

ALA-PDT promotes the death and contractile capacity of hypertrophic scar fibroblasts through inhibiting the TGF-β1/Smad2/3/4 signaling pathway

BackgroundHypertrophic scars, an abnormal wound-healing response to burn injuries, are characterized by massive fibroblast proliferation and excessive deposition of extracellular matrix and collagen. 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) is a promising therapy for hypertrophic scar, details of the mechanisms remain to be elucidated. In this study, we aimed to investigate the molecular mechanisms involved in ALA-PDT against hypertrophic scar fibroblasts. MethodsThe morphologies of hypertrophic scar fibroblasts (HSFs) treated with ALA-PDT were observed under a light microscopy. The viability of HSFs was detected using the CCK-8 assay. HSFs-populated collagen gel contraction assays were conducted to examine the fibroblast contractility and the cytotoxicity of HSFs in 3D collagen tissues were observed using confocal microscopy. The effect of ALA-PDT on TGF-β1/Smad2/3/4 signaling pathway activation and effector gene expression were verified by immunoprecipitation, western blot and real-time quantitative PCR analysis. ResultsWe observed significant changes in cell morphology after ALA-PDT treatment of HSFs. As ALA concentration and light dose increased, the viability of HSFs significantly decreased. ALA-PDT can significantly alleviate the contractile capacity and promote the death of HSFs induced by TGF-β1 treatment in a three-dimensional collagen culture model. TGF-β1 treatment of HSFs can significantly induce phosphorylation of Smad2/3 (p-Smad2/3) in whole cells, as well as p-Smad2/3 and Smad4 proteins into the nucleus and increase the mRNA levels of collagen 1/3 and α-SMA. ALA-PDT hampers the TGF-β1-Smad2/3/4 signaling pathway activation by inducing K48-linked ubiquitination and degradation of Smad4. ConclusionsOur results provide evidence that ALA-PDT can inhibit fibroblast contraction and promote cell death by inhibiting the activation of the TGF-β1 signaling pathway that mediates hypertrophic scar formation, which may be the basis for the efficacy of ALA-PDT in the treatment of hypertrophic scars.

5-ALA-PDT induced ferroptosis in keloid fibroblasts via ROS, accompanied by downregulation of xCT, GPX4

Keloids display many cancerous properties, including uncontrolled and invasive growth, high rates of recurrence as well as similar bioenergetics. 5-aminolevulinic acid-based photodynamic therapy (5-ALA-PDT) is an effective treatment that performs cytotoxic effects by producing reactive oxygen species (ROS), which is linked to lipid peroxidation and ferroptosis. Herein, we explored underlying mechanisms of 5-ALA-PDT against keloids. We identified that 5-ALA-PDT led to elevated levels of ROS and lipid peroxidation in keloid fibroblasts, accompanied by downregulation of xCT and GPX4, which are associated with anti-oxidation effects and ferroptosis inhibition. These results may indicate that 5-ALA-PDT treatment increases ROS while inhibiting xCT and GPX4, thus promoting lipid peroxidation to induce ferroptosis in keloid fibroblasts.

High-frequency ultrasound assessment of vulvar lichen sclerosus treated with photodynamic therapy.

Patients with vulvar lichen sclerosus (VLS) are faced with a decreased quality of life and an increased risk of vulvar malignancy. 5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) can serve as an alternative for refractory VLS patients. However, high-frequency ultrasound (HFUS) has never been introduced in the ALA-PDT outcome assessment for VLS patients. A prospective study was conducted. Refractory VLS patients received two treatment courses of ALA-PDT (3 times of remedies at 2-week intervals for each course), and underwent clinical, HFUS and histopathological assessment. Statistical analysis comparing parameters at baseline and after ALA-PDT was performed. Thirty-one VLS patients were included. Both subjective symptoms (itch and burning pain) and objective severity (lesion size and hypopigmentation) were relieved significantly after ALA-PDT treatment. Hypoechoic dermal band (HDB) thickness revealed by HFUS decreased progressively with successive ALA-PDT treatment, and the reduction value had a positive correlation with the reduction of inflammatory infiltration depth in histopathology. Collagen homogenization depth decrease was also noticed. Besides, adverse effects were recorded, mainly as mild and transient post-treatment edema and pain. ALA-PDT is an effective and safe therapeutic option for refractory VLS patients. HFUS can act as a complement to the non-invasive treatment monitoring for its objectivity, quantifiability and precision in the distinct vertical perspective.

Clinical practice Guidelines for 5-Aminolevulinic acid photodynamic therapy for acne vulgaris in China.

A variety of evidence suggest that 5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) is clinically effective in management of acne vulgaris. Several clinical guidelines for acne recommend PDT as an alternative treatment modality for severe acne. However, there is a lack of detailed clinical guideline for PDT in acne treatment. To propose up-to-date, evidence-based and practical recommendations on application of ALA-PDT for acne vulgaris, dermatologists and PDT experts from the Photodynamic Therapy Research Center of the CMA and Photodynamic Therapy Rehabilitation Training Center of CARD achieved consensus and guidelines based on careful evaluation of published literature, expert opinions and experience. ALA-PDT plays a therapeutic role in all four major pathogenesis of acne, and is suitable for moderate to severe acne and scar-prone acne, especially for patients who cannot tolerate or refused systemic antibiotics and isotretinoin. The efficacy and adverse reactions of ALA-PDT are closely related to therapeutic parameters including ALA concentration, incubation time, light source and dosage. Proper pretreatment helps to improve transdermal absorption of ALA and enhances its efficacy. We reviewed and proposed recommended protocols for four PDT procedures including conventional PDT (C-PDT), modified painless PDT (M-PDT), intense pulsed light PDT (IPL-PDT) and daylight PDT (DL-PDT). M-PDT with lower ALA concentration (3-5%), shorter incubation time (30 mins), and lower dose but prolonged illumination (630nm, 40-60 mW/cm2, 150 J/cm2) can improve lesions of moderate to severe acne vulgaris effectively with minimal pain and easier manipulation, and thus was recommended by Chinese dermatologists. Lastly, management of adverse reactions were addressed.

CBMS-9 INFLUENCE OF HYPOXIA ON PHOTODYNAMIC THERAPY WITH 5-AMINOLEVULINIC ACID FOR MALIGNANT GLIOMA STEM CELLS

Abstract Background Glioblastoma is a highly malignant brain tumor refractory to standard treatment and its refractoriness is attributed to the presence of a small number of glioma stem cells (GSCs) that survive in a harsh microenvironment. The aim of this study was to investigate the effect of hypoxic conditions on the sensitivity of GSCs to 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT). Materials and Methods Six human GSClines: three GSCs classified as Mesenchymal subtype and three GSCs classified as Proneural subtype, were divided into normoxia-GSCs (O2: 21%) and hypoxia-GSCs (O2: 5%) groups. To compare the effects of different oxygen partial pressures on protoporphyrin-IX (PpIX) biosynthetic activity, the expression levels of PpIX biosynthetic enzymes and transporters were examined by qRT-PCR and intracellular PpIX concentration was measured by flow cytometry. In addition, the sensitivity of these two cell groups to ALA-PDT was assessed in vitro. Results Hypoxia-GSCs showed higher mRNA levels of FECH (ferrochelatase), which is required for iron synthesis to convert PpIX to haem, compared to Normoxia-GSCs. Flow cytometry revealed that the accumulation of PpIX from exogenous ALA in Hypoxia-GSCs was reduced compared to in Normoxia-GSCs. Despite this, no Hypoxia-GSC lines showed significantly reduced sensitivity to ALA-PDT compared to Normoxia-GSCs. Conclusion Hypoxia-GSCs had lower intracellular PpIX accumulation than Normoxia-GSCs due to increased gene expression of FECH, and that their sensitivity to ALA- PDT was reduced less, despite accumulating lower concentrations of PpIX. ALA-PDT is at least a potentially effective therapy for hypoxia-tolerant GSCs that exist in hypoxia at 5% oxygen concentration.

CBMS-10 INFLUENCE OF HYPOXIA ON PHOTODYNAMIC THERAPY WITH 5-AMINOLEVULINIC ACID FOR MALIGNANT GLIOMA STEM CELLS

Abstract Background Glioblastoma is a highly malignant brain tumor refractory to standard treatment and its refractoriness is attributed to the presence of a small number of glioma stem cells (GSCs) that survive in a harsh microenvironment. The aim of this study was to investigate the effect of hypoxic conditions on the sensitivity of GSCs to 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT). Materials and Methods Six human GSClines: three GSCs classified as Mesenchymal subtype and three GSCs classified as Proneural subtype, were divided into normoxia-GSCs (O2: 21%) and hypoxia-GSCs (O2: 5%) groups. To compare the effects of different oxygen partial pressures on protoporphyrin-IX (PpIX) biosynthetic activity, the expression levels of PpIX biosynthetic enzymes and transporters were examined by qRT-PCR and intracellular PpIX concentration was measured by flow cytometry. In addition, the sensitivity of these two cell groups to ALA-PDT was assessed in vitro.Results:Hypoxia-GSCs showed higher mRNA levels of FECH (ferrochelatase), which is required for iron synthesis to convert PpIX to haem, compared to Normoxia-GSCs. Flow cytometry revealed that the accumulation of PpIX from exogenous ALA in Hypoxia-GSCs was reduced compared to in Normoxia-GSCs. Despite this, no Hypoxia-GSC lines showed significantly reduced sensitivity to ALA-PDT compared to Normoxia-GSCs.Conclusion:Hypoxia-GSCs had lower intracellular PpIX accumulation than Normoxia-GSCs due to increased gene expression of FECH, and that their sensitivity to ALA- PDT was reduced less, despite accumulating lower concentrations of PpIX. ALA-PDT is at least a potentially effective therapy for hypoxia-tolerant GSCs that exist in hypoxia at 5% oxygen concentration.

Synthetic biology-instructed transdermal microneedle patch for traceable photodynamic therapy

5-Aminolevulinic acid-based photodynamic therapy heavily depends on the biological transformation efficiency of 5-aminolevulinic acid to protoporphyrin IX, while the lack of an effective delivery system and imaging navigation are major hurdles in improving the accumulation of protoporphyrin IX and optimizing therapeutic parameters. Herein, we leverage a synthetic biology approach to construct a transdermal theranostic microneedle patch integrated with 5-aminolevulinic acid and catalase co-loaded tumor acidity-responsive copper-doped calcium phosphate nanoparticles for efficient 5-aminolevulinic acid-based photodynamic therapy by maximizing the enrichment of intratumoral protoporphyrin IX. We show that continuous oxygen generation by catalase in vivo reverses tumor hypoxia, enhances protoporphyrin IX accumulation by blocking protoporphyrin IX efflux (downregulating hypoxia-inducible factor-1α and ferrochelatase) and upregulates protoporphyrin IX biosynthesis (providing exogenous 5-aminolevulinic acid and upregulating ALA-synthetase). In vivo fluorescence/photoacoustic duplex imaging can monitor intratumoral oxygen saturation and protoporphyrin IX metabolic kinetics simultaneously. This approach thus facilitates the optimization of therapeutic parameters for different cancers to realize Ca2+/Cu2+-interferences-enhanced repeatable photodynamic therapy, making this theranostic patch promising for clinical practice.

C5α secreted by tumor mesenchymal stem-like cells mediates resistance to 5-aminolevulinic acid-based photodynamic therapy against glioblastoma tumorspheres.

Advancements in photodynamic diagnosis (PDD) and photodynamic therapy (PDT) as a standard care in cancer therapy have been limited. This study is aimed to investigate the clinical availability of 5-aminolevulinic acid (5-ALA)-based PDD and PDT in glioblastoma (GBM) patient-derived tumorspheres (TSs) and mouse orthotopic xenograft model. PDT was performed using a 635nm light-emitting diode (LED). Transcriptome profiles were obtained from microarray data. For knockdown of C5α, siRNA was transfected into tumor mesenchymal stem-like cells (tMSLCs). The invasiveness of TSs was quantified using collagen-based 3D invasion assays. Treatment with 1mM 5ALA induced distinct protoporphyrin IX (PpIX) fluorescence in GBM TSs, but not in non-tumor cells or tissues, including tMSLCs. These observations were negatively correlated with the expression levels of FECH, which catalyzes the conversion of accumulated PpIX to heme. Furthermore, the 5-ALA-treated GBM TSs were sensitive to PDT, thereby significantly decreasing cell viability and invasiveness. Notably, the effects of PDT were abolished by culturing TSs with tMSLC-conditioned media. Transcriptome analysis revealed diverse tMSLC-secreted chemokines, including C5α, and their correlations with the expression of stemness- or mesenchymal transition-associated genes. By adding or inhibiting C5α, we confirmed that acquired resistance to PDT was induced via tMSLC-secreted C5α. Our results show substantial therapeutic effects of 5-ALA-based PDT on GBM TSs, suggesting C5α as a key molecule responsible for PDT resistance. These findings could trigger PDT as a standard clinical modality for the treatment of GBM.

The role of Shikonin in improving 5-aminolevulinic acid-based photodynamic therapy and chemotherapy on glioblastoma stem cells

Glioblastoma multiforme is a malignant neoplasia with a median survival of less than two years and without satisfactory therapeutic options. The so-called glioblastoma stem cells escape the established radio- and chemotherapies and lead to tumor recurrence in most cases. The alkaloid Shikonin with its various anti stem cell properties and the interstitial photodynamic therapy with 5-aminolevulinic acid seem to be promising new options in the therapy of glioblastoma. In this study, in vitro investigations were performed to observe the influence of Shikonin on viability, proliferation, induction of apoptosis and the capability of forming tumor spheres in U-87 MG and the primary glioblastoma cell line GB14. The combined effect with the chemotherapeutic temozolomide and photodynamic treatment on the mRNA expression of glioma specific stem cell markers and further examined intracellular protoporphyrin IX accumulation under Shikonin treatment was analyzed. Shikonin effectively inhibited the capability of forming tumor spheres and enhanced temozolomide effectiveness in the reduction of proliferation and in the induction of apoptosis. Additionally, Shikonin increased the mRNA expression of the tumor suppressing Neurofibromatosis type 1 (NF1) gene and showed modulating effects on intracellular protoporphyrin IX.

Vitamin D enhances the sensitivity of breast cancer cells to the combination therapy of photodynamic therapy and paclitaxel

PurposeGiven that Vitamin D (VD) has been confirmed to reinforce the toxic effects of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) towards breast cancer, this study was designed to decipher the combined effects of VD, ALA-PDT and paclitaxel (PTX). MethodsThiazolyl blue tetrazolium bromide assay was conducted to gauge the viability of breast cancer cells treated with ALA-PDT and PTX alone or in combination. The cell migration, invasion and apoptosis were measured by wound healing, transwell and flow cytometry assays, respectively. Xenograft tumor models were established and tumor volume and weight were recorded. The expression of Bcl-2, Bax and cleaved caspase-3 in cells and tumor tissues was determined by western blot assay. ResultsBoth ALA-PDT and PTX alone inhibited viability in a dose-dependent manner, blocked migration and invasion, boosted apoptosis, down-regulated Bcl-2 expression and upregulated the expression of Bax and cleaved caspase-3 in breast cancer cells. More significant effects on the above-mentioned factors were induced by ALA-PDT and PTX in combination. Moreover, ALA-PDT and PTX in combination also suppressed the growth of xenograft tumors and Bcl-2 expression while promoting the expression of Bax and cleaved caspase-3 in tumors. In contrast, VD had no effect on tumor growth and the expression of Bcl-2, Bax and cleavedcaspase-3, but intensified the combined effects of ALA-PDT and PTX. ConclusionVD could enhance the therapeutic effects of ALA-PDT combined with PTX on tumor growth and cell apoptosis.

Molecular characterization of gene expression changes in murine cutaneous squamous cell carcinoma after 5-aminolevulinic acid photodynamic therapy

5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) is an effective therapy in treating inoperable cutaneous squamous cell carcinoma (cSCC) in China. However, its exact mechanism in treating cSCC is still unclear. Here, we analyzed expression profiles of lncRNAs and mRNAs of cSCC after ALA-PDT in a mouse model using Mouse Transcriptome Assay 1.0 chip. A total of 592 and 828 differentially expressed genes were identified in comparisons of ALA-PDT after 3 h vs. control, ALA-PDT after 6 h vs. control respectively. Regarding the lncRNAs analysis, a total of 185 and 410 differentially expressed lncRNAs were sought out. Bioinformatics analyses including Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway, pathway relation network, and gene set enrichment analysis revealed that the pathways of ALA-PDT in treating cSCC were mainly associated with immune regulation, NF-κB signaling pathway, TLR signaling pathway, PI3K-Akt signaling pathway, TNF signaling pathway, and MAPK signaling pathway, which was validated by western blot analysis. Furthermore, a lncRNA-mRNA co-expression network revealed 118 network pairs comprising 36 lncRNAs and 68 mRNAs. These findings provide a basis for investigations into the treatment mechanisms of ALA-PDT in treating cSCC.

Daylight-PDT: everything under the sun.

5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) was first implemented over three decades ago and has since been mainly part of clinical practice for the management of pre-cancerous and cancerous skin lesions. Photodynamic therapy relies on the combination of a photosensitizer, light and oxygen to cause photo-oxidative damage of cellular components. 5-Aminolevulinic acid (ALA) is a natural precursor of the heme biosynthetic pathway, which when exogenously administered leads to the accumulation of the photoactivatable protoporphyrin IX. Although, effective and providing excellent cosmetic outcomes, its use has been restricted by the burning, stinging, and prickling sensation associated with treatment, as well as cutaneous adverse reactions that may be induced. Despite intense research in the realm of drug delivery, pain moderation, and light delivery, a novel protocol design using sunlight has led to some of the best results in terms of treatment response and patient satisfaction. Daylight PDT is the protocol of choice for the management of treatment of multiple or confluent actinic keratoses (AK) skin lesions. This review aims to revisit the photophysical, physicochemical and biological characteristics of ALA-PDT, and the underlying mechanisms resulting in daylight PDT efficiency and limitations.

Microarray Analysis Elucidates Potential Mechanism of 5-Aminolevulinic Acid-Based Photodynamic Therapy in Treating Cutaneous Squamous Cell Carcinoma

Microarray Analysis Elucidates Potential Mechanism of 5-Aminolevulinic Acid-Based Photodynamic Therapy in Treating Cutaneous Squamous Cell Carcinoma

Patterns of multiple human papillomavirus clearance during 5-aminolevulinic acid-based photodynamic therapy in patients with genital warts

BackgroundMultiple human papillomavirus infections are commonly encountered in genital warts. Infection can be eliminated using 5-aminolevulinic acid-based photodynamic therapy. The aim of this study was to identify the preponderant genotypes and patterns of human papillomavirus co-infection clearance during photodynamic therapy in patients with genital warts. MethodsWe conducted a retrospective study between January 2020 and February 2021 at two hospitals in Guangzhou, China. Human papillomavirus typing and quantitative detection were performed before starting treatment and after each session of photodynamic therapy. ResultsA total of 97 patients participated in the study. Co-infections with low-risk and high-risk types were common in genital warts. Types 6 was the most common type detected, followed by types 52, 11, 58, 51 and 56. Patients with multiple infections were more likely to have high-risk human papillomavirus infection. The viral load of high-risk human papillomavirus before treatment was significantly lower than that of low-risk human papillomavirus, and decreased faster during therapy. In addition, high-risk types were cleared more readily than low-risk types, and 51.4% of high-risk types were eliminated after three rounds of therapy. A transient increase in viral load, especially low-risk types, was observed after two sessions of therapy. ConclusionsLow-risk human papillomavirus was preponderant in patients co-infected with low-risk and high-risk types. Photodynamic therapy effectively eliminated multiple human papillomavirus infections. The response to photodynamic therapy was mainly determined by the low-risk types in patients infected with combinations of low-risk and high-risk types.

Predictors of therapeutic efficacy of 5-aminolevulinic acid-based photodynamic therapy in human prostate cancer

BackgroundPhotodynamic therapy (PDT) is a minimally invasive cancer therapy. However, its therapeutic efficacy for prostate cancer is not yet fully understood. In this study, the predictors of therapeutic efficacy of 5-aminolevulinic acid-based PDT (ALA-PDT) on prostate cancer cells are investigated. Materials and methodsThe human prostate cancer cell lines, PC-3, 22Rv1, DU145, and LNCap were used to investigate the effects of ALA-PDT on protoporphyrin IX (PpIX) intracellular accumulation, which was measured by flow cytometry. The cytotoxicity of ALA-PDT was evaluated by MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay. The levels of porphyrin metabolism-related enzyme and transporter mRNA were comprehensively evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was evaluated by Western blot. A xenograft model was created using PC-3 and 22Rv1, and then, pathological analysis was performed to determine the therapeutic effect of ALA-PDT ResultsPC-3 and LNCap cells showed high accumulation of PpIX and high sensitivity to ALA-PDT, while 22Rv1 and DU145 showed low accumulation of PpIX and low sensitivity to ALA-PDT. ALA-PDT-induced cytotoxicity correlated negatively with PpIX accumulation. The in vitro assays identified the ATP-binding cassette transporter subfamily G2 (ABCG2) transporter dimer as a predictor of treatment response. In vivo immunohistochemical staining of ABCG2 transporter showed low expression in PC-3 cells and high expression in 22Rv1 cells, and ALA-PDT-induced tumor tissue degeneration was greater in PC-3 cells than in 22Rv1 cells. ConclusionThe ABCG2 transporter is a useful predictor of the therapeutic effect of ALA-PDT on human prostate cancer cells.

A clinical study of carbon dioxide lattice laser-assisted or microneedle-assisted 5-aminolevulinic acid-based photodynamic therapy for the treatment of hypertrophic acne scars.

To study the clinical efficacy, recurrence rate and safety of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) combined with microneedle or CO2 lattice laser (CO2FL), in comparison with intrascar betamethasone injection in the treatment of hypertrophic acne scar. Fifty-two patients with hypertrophic acne scars at the mandibular angle were enrolled and assigned to different therapy groups. Sixteen patients were treated with microneedle-assisted incorporation of ALA. Twenty-eight patients underwent CO2FL-assisted incorporation of ALA. Eight patients received standard therapy with intrascar injection of glucocorticoid. Two dermatologists, blinded to the therapy groups, independently evaluated the scars in all patients using the average value of the Vancouver Scar Scale score, which was treated as an integer variable. After three rounds of treatment, there was no significant difference in therapeutic effective rate among the microneedle, laser and topical glucocorticoid groups (93.75% vs 100% vs 100%, P=.855). One out of 16 patients (6.25%) in the microneedle group, no patient (0%) in the laser group and two out of eight patients (25%) in the topical glucocorticoid group had recurrence. The laser group showed a higher rate of adverse effects, which were usually mild and reversible, except for pigmentation. Adverse reactions could be completely subsided within 3weeks. Either CO2FL or microneedle combined ALA-PDT for hypertrophic scar, as to topical glucocorticoid therapy, showed equivalent clinical effects but lower recurrence rate within 6months of follow-up period.