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Alternative Tumor-Targeting Strategies
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
At first sight, aminolevulinic acid (ALA) and methyl aminolevulinate (MetvixTM) appear to be in a completely different structural family to the porphyrin-based agents as a photosensitizers. However, they act as prodrugs that undergo metabolic conversion to photoactive porphyrins (i.e., protoporphyrin IX) which accumulate in the skin lesions to which it is applied.
Aminolevulinic Acid
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Aminolevulinic acid is a topically administered metabolic precursor of protoporphyrin IX. After topical administration, aminolevulinic acid is converted to protoporphyrin IX, which is a photosensitizer. When the proper wavelength of light activates protoporphyrin IX, singlet oxygen is produced, resulting in a local cytotoxic effect. Aminolevulinic acid is indicated for use in photodynamic therapy to treat actinic keratoses and superficial basal cell carcinomas. In pharmaceutical products, aminolevulinic acid is employed as aminolevulinic acid hydrochloride (CAS number 5451-09-2, EC number 226-679-5, molecular formula C5H10ClNO3) (1).
Photodynamic Therapy
Published in Henry W. Lim, Nicholas A. Soter, Clinical Photomedicine, 2018
The potential toxicities of topical δ-aminolevulinic acid also need to be defined. In human volunteers, the only described systemic toxicity from relatively large oral dosages of δ-aminolevulinic acid was transient photosensitivity (1–2 days) (49, 50). After limited topical administration, the systemic burden is likely to be negligible.
Comparison of the efficacy of focused ultrasound at different focal depths in treating vulvar lichen sclerosus
Published in International Journal of Hyperthermia, 2023
Ru Jia, Can Wu, Xiaoxu Tang, Miaomiao He, Xinglin Liu, Chang Su, Chengzhi Li
Physical treatment for VLS includes PDT and FxCO2 therapy. PDT remains a clinical challenge, and no standardized treatment protocol regarding the concentration of aminolevulinic acid, incubation time, light source (power and wavelength), exposure time (energy and power density) and number and frequency of VLS treatment repetitions has been established [22,23]. For FxCO2 therapy, randomized controlled trials with large sample sizes and standardized measurement criteria are still lacking. Recent short-term follow-up studies showed that the recurrence rate of symptoms increases with the prolongation of operative time after treatment, thus requiring repeated treatment. Therefore, further data collection is still needed to investigate the effectiveness and recurrence rate of laser technology for VLS [24].
Suppression of resistance to aminolevulinic acid-based photodynamic therapy in esophageal cell lines by administration of iron chelators in collagen type I matrices
Published in International Journal of Radiation Biology, 2023
Beata Čunderlíková, Adriana Kalafutová, Pavel Babál, Peter Mlkvý, Tibor Teplický
When colonies of cells in plastic dishes and cellular clusters in collagen type I gels were formed, the culture medium was replaced with a fresh one. Aminolevulinic acid-based PDT efficacy was evaluated in samples of cell colonies in plastic dishes in two culture media, DMEM and RPMI 1640, the composition of which differ in iron content. Iron chelators, either DFO (Sigma, Germany) or pyridoxal isonicotinoyl hydrazone (PIH; Abcam, UK), were added to final concentrations of 100 µM and 40 µM, respectively. Subsequently, aminolevulinic acid (ALA; Acros Organics, Geel, Belgium) was added from a 10 mM stock solution freshly prepared in a culture medium with 10% FBS to final concentrations specified in the Results section and consistent with our previous studies (Mateašík et al. 2017). Following a four-hour incubation period in the incubator in the darkness, the culture medium was replaced with a fresh medium without ALA and iron chelators. The dishes with cell colonies or with 3 D cell cultures were then illuminated with a red light for time periods indicated in the Results section.
A retrospective study comparing different injection approaches of 5-aminolevulinic acid in patients with non-melanoma skin cancer
Published in Journal of Dermatological Treatment, 2022
Weihong Zhao, Jun Wang, Ying Zhang, Baoyong Zheng
Needle-free injection of intralesional 5-aminolevulinic acid followed by irradiation with red light reported high treatment response for non-melanoma skin cancer patients of advanced age, patients with squamous cell carcinoma and Paget’s disease. Also, it showed higher patients’ satisfaction, manageable post-treatment pain, and fewer treatment-emergent adverse effects during the treatment of non-melanoma skin cancer than intralesional 5-aminolevulinic acid through the traditional needle or plum-blossom needle followed by irradiation with the red light. Moreover, intralesional 5-aminolevulinic acid through the Chinese dermal needle also has promising results for non-melanoma skin cancer compared to conventional intralesional 5-aminolevulinic acid injection therapy. Large, randomized trials are required for verification.