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Different types of photosensitizers (PSs) have different dynamics and intensities of accumulation, depending on the type of tumor or different areas within the same tumor. This determines the effectiveness of fluorescence diagnostics and photodynamic therapy (PDT). This paper studies the processes of 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) and chlorin e6 (Ce6) accumulation in the central and border zones of a tumor after combined administration of two PSs into the patient's body. Fluorescence diagnostic methods have shown that sublingual administration of 5-ALA leads to the more intense accumulation of PpIX in a tumor compared to oral administration. Differences have been identified in the dynamics of 5-ALA-induced PpIX and Ce6 accumulation in the central and border zones of the tumor, as well as normal tissues. Ce6 accumulates mainly in the central zone of the tumor while PpIX accumulates in the border zone of the tumor. All patients with combined PDT experienced complete therapeutic pathomorphosis and relapse-free observation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Background: Female vulvar lichen sclerosus (VLS) is a chronic inflammatory skin disease of the vulva and its etiology is unknown. The main clinical symptoms are itching, burning and dyspareunia, and there is a lack of effective treatment., Methods: Clinical and follow-up data of women with VLS who underwent 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) from January 2023 to December 2023 in the department of obstetrics and gynecology, Qilu Hospital of Shandong University, were retrospectively analyzed. According to the inclusion and exclusion criteria, 36 patients with VLS who received ineffective conventional treatment (intractable VLS) were enrolled. Objective signs and subjective symptoms of vulvar lesions were recorded before treatment and 6 months after the end of treatment according to corresponding scoring criteria. Quality of life was evaluated using the Dermatology Life Quality Index (DLQI)., Results: All patients received six sessions of ALA-PDT treatment and follow-up visits. After ALA-PDT treatment, 24 of 36 (66.67 %) patients' itching symptoms completely disappeared, 10 of 36 (27.78 %) patients' itching symptoms were relieved from severe to mild, and only 2 of 36 (5.56 %) patients' symptoms were not significantly relieved. 16 of 36 (44.4 %) patients' itching symptoms completely disappeared, 9 of 36 (25 %) patients' itching symptoms were relieved from severe to mild, and only 2 of 36 (5.56 %) patients still had severe pain. Compared to 22 patients with dyspareunia before treatment, only 9 patients still had dyspareunia with varying degrees of dyspareunia relief after treatment. Clinical signs improved significantly in the patients after ALA-PDT treatment. The total scores of clinical signs were (5.31 ± 1.67 vs 3.67 ± 1.71) before and after treatment. All patients showed improvement in DLQI after treatment. The main side effects of ALA-PDT were pain, erythema and swelling which were transient and tolerable. All patients were "satisfied" or "very satisfied" with the results of the treatment., Conclusions: ALA-PDT is a safe and effective treatment for women with intractable vulva lichen sclerosus., Competing Interests: Declaration of competing interest No conflict of interest exits in the submission of this manuscript, and manuscript is approved by all authors for publication., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Oral 5-aminolevulinic acid for transurethral resection of bladder tumor reduces bladder cancer recurrence compared with standard white-light transurethral resection of bladder tumor. However, data regarding risks of adverse events with this drug are unclear. The aim of the present study was to identify risk factors associated with oral 5-aminolevulinic acid induced adverse events in photodynamic diagnosis-transurethral resection of bladder tumor., Methods: We studied 104 cases of 5-aminolevulinic acid-photodynamic diagnosis-transurethral resection of bladder tumor from October 2021 to April 2023, administering 20 mg/kg 5-aminolevulinic acid orally at least 2 h pre-surgery. Four major adverse events associated with 5-aminolevulinic acid were selected to identify risk factors for their occurrence, including perioperative hypotension, nausea and/or vomiting, photosensitivity, and liver dysfunction. Univariate and multivariate analyses were conducted to identify the risk factors of those adverse events., Results: Perioperative hypotension (11.5 %), nausea and/or vomiting (37.5 %) photosensitivity (31.7 %), and liver dysfunction (51.9 %) were observed. Multivariate analyses revealed that spinal anesthesia was associated with hypotension (p = 0.02), whereas advanced age (p < 0.01) and higher body mass index (p < 0.01) were associated with nausea and/or vomiting. Also, male sex (p < 0.01) and longer operative time (p = 0.01) were associated with photosensitivity, and renin-angiotensin system inhibitors use was associated with postoperative liver dysfunction (p < 0.01)., Conclusions: For elderly male obese patients taking renin-angiotensin system inhibitors, particular attention is needed during the perioperative period of photodynamic diagnosis-transurethral resection of bladder tumor under spinal anesthesia due to the higher risk of onset of the adverse events involved in oral administration of 5-aminolevulinic acid., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Candidiasis is a common fungal infection, with Candida tropicalis infections being relatively rare. These infections develop into skin fungal infections under conditions such as broad-spectrum antibiotic use, diabetes, and immunosuppression. Traditionally, antifungal drugs have been the primary treatment; however, issues like hepatotoxicity and the need for long-term use persist. Consequently, new treatment approaches are essential. Most previous reports have focused on Candida albicans, with fewer addressing Candida tropicalis. This study reports a case where a patient with a skin Candida tropicalis infection was treated with a combination of surgery and ALA photodynamic therapy(635 nm, 120 J/cm 2 , 177 mW/cm 2 ). After just one session of this combined treatment, the patient achieved significant clinical remission. Therefore, the combination of surgery and ALA-PDT may offer a safe and effective treatment option., (Copyright © 2024. Published by Elsevier B.V.)

As a precursor of protoporphyrin IX (PpIX), an endogenous pro-apoptotic and fluorescent molecule, 5-Aminolevulinic acid (5-ALA) has gained substantial attention for its potential in fluorescence-guided surgery as well as photodynamic therapy (PDT). Moreover, 5-ALA-PDT has been suggested as a promising chemo-radio sensitization therapy for various cancers. However, insufficient 5-ALA-induced PpIX fluorescence and the induction of multiple resistance mechanisms may hinder the 5-ALA-PDT clinical outcome. Reduced efficacy and resistance to 5-ALA-PDT can result from genomic alterations, tumor heterogeneity, hypoxia, activation of pathways related to cell surveillance, production of nitric oxide, and most importantly, deregulated 5-ALA transporter proteins and heme biosynthesis enzymes. Understanding the resistance regulatory mechanisms of 5-ALA-PDT may allow the development of effective personalized cancer therapy. Here, we described the mechanisms underlying resistance to 5-ALA-PTD across various tumor types and explored potential strategies to overcome this resistance. Furthermore, we discussed future approaches that may enhance the efficacy of treatments using 5-ALA-PDT., Competing Interests: Declaration of competing interest The authors declare no conflict of interest. All authors have been participated in the preparation of the manuscript, and have given their agreement to submit this manuscript in the present format., (Copyright © 2024. Published by Elsevier Inc.)

Dermatosis papulosa nigra (DPN) is a type of benign epidermal hyperplasia that affects the appearance of patients and poses a threat to their physical and mental health. Photodynamic therapy (PDT) has been shown to have the advantages of non-invasiveness, efficacy, and low recurrence in the treatment of skin disorders. However, no studies have been reported on the use of PDT for the treatment of DPN. Therefore, we used PDT for the first time to treat DPN and monitor its efficacy. Forty-five patients with DPN diagnosed at the outpatient clinic of Changzhou First People's Hospital were treated with 10 % 5-aminolevulinic acid (ALA) once a week for four consecutive weeks and followed for 3 months. After four treatment sessions, the cure rate among the 45 patients was 71.1 %, and the overall efficacy rate was 93.3 %. The most common adverse reactions were mild erythema, edema, and temporary pigmentation. PDT is expected to become a new and effective treatment for DPN., Competing Interests: Declaration of competing interest None declared., (Copyright © 2024. Published by Elsevier B.V.)

Objectives: In a primary analysis of data from the BRIGHT study (UMIN000035712), photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT) using oral 5-aminolevulinic acid hydrochloride reduced residual tumors in high-risk non-muscle invasive bladder cancer (NMIBC). We aimed to evaluate the effectiveness of PDD-TURBT for intravesical recurrence after a second transurethral resection for high-risk NMIBC., Methods: High-risk NMIBC patients initially treated with PDD-TURBT (PDD group) were prospectively registered between 2018 and 2020. High-risk patients with NMIBC who were initially treated with white-light TURBT (WL group) were retrospectively registered. Intravesical recurrence-free survival after the second transurethral resection was compared between the PDD and WL groups using propensity score matching analysis., Results: In total, 177 patients were enrolled in the PDD group, and 306 patients were registered in the WL group. After propensity score matching (146 cases in each group), intravesical recurrence within 1 year was significantly less frequent in the PDD group than in the WL group (p = 0.004; hazard ratio [HR] 0.44, 95% confidence interval [CI]: 0.25-0.77). In subgroup analysis, PDD-TURBT showed a particularly high efficacy in reducing intravesical recurrence within 1 year, especially in cases of tumors measuring less than 3 cm (p = 0.003; HR 0.31, 95% CI: 0.14-0.67), absence of residual tumor at second transurethral resection (p = 0.020; HR 0.37, 95% CI: 0.16-0.86), and no postoperative intravesical Bacillus Calmette-Guérin therapy (p < 0.001; HR 0.27, 95% CI: 0.13-0.58)., Conclusions: PDD-TURBT may reduce short-term intravesical recurrence in patients with high-risk NMIBC., (© 2024 The Authors. International Journal of Urology published by John Wiley & Sons Australia, Ltd on behalf of The Japanese Urological Association.)

Objective: Intraoperative hypotension remains a serious adverse event of photodynamic diagnosis-assisted transurethral resection of bladder tumor with oral administration of 5-aminolevulinic acid. We conducted a re-analysis of perioperative hypotension in photodynamic diagnosis-assisted transurethral resection of the bladder tumor with oral 5-aminolevulinic acid to ascertain its safety., Methods: A total of 407 cases who underwent transurethral resection of bladder tumors in our institution were reviewed (274 cases for the PDD group with photodynamic diagnosis and 133 for the white light (WL) group without). A classification of hypotension severity was devised to identify risk factors for clinically troublesome hypotension. The distribution of hypotension severity in each of the PDD and WL groups was compared. Additionally, the patient background and perioperative data by hypotension severity were compared only in the PDD group., Results: More patients with moderate and severe hypotension were noted in the PDD group. The renal function was lower with increasing hypotension severity in the PDD group. More patients on general anesthesia were included in the mild and moderate hypotension group, whereas more patients on spinal anesthesia were included in the severe hypotension group. Furthermore, the frequency of side effects other than hypotension tended to increase with hypotension severity., Conclusions: Renal function impairment and the other adverse effects of 5-aminolevulinic acid may be risk factors for severe hypotension. Mild or moderate hypotension may be caused by general anesthesia and severe hypotension may be caused by spinal anesthesia. To elucidate specific risk factors, further case-control studies are warranted., (© 2024 The Japanese Urological Association.)

Background and Aim: The diagnostic accuracy for cholangiocarcinoma (CCA) is inadequate, necessitating the exploration of novel diagnostic approaches. Protoporphyrin IX (Pp IX), a metabolic product of 5-aminolevulinic acid (5-ALA), emits red fluorescence upon blue light exposure. Because it accumulates selectively in cancer cells, photodynamic diagnosis using 5-ALA (5-ALA-PDD) has been integrated into clinical practice for diverse cancer types. Nevertheless, there is currently no device capable of capturing Pp IX-derived fluorescence for real-time 5-ALA-PDD within the biliary tract, largely due to challenges in device miniaturization., Methods: To investigate the feasibility of real-time 5ALA-PDD in CCA, we developed two essential components of the cholangioscopy system: a small-diameter flexible camera and a light guide for emitting blue light. We evaluated the detectability of Pp IX fluorescence using these devices in experimental gels and animal models., Results: Our camera and light guide were smoothly inserted into the lumen of existing cholangioscopes. Incorporating a long-pass filter at the camera tip enabled efficient detection of red fluorescence without significantly impacting white-light observation. The integration of these devices facilitated clear visualization of red fluorescence from gels containing Pp IX at concentrations of 5 μM or higher. Additionally, when observing subcutaneous human CCA tumor models in nude mice treated with 5-ALA, we successfully demonstrated distinct red fluorescence from Pp IX accumulation in tumors compared to peritumoral subcutaneous areas., Conclusion: The integration of our device combination holds promise for real-time 5-ALA-PDD in human CCA, potentially enhancing the diagnostic accuracy for this complex condition., Competing Interests: Declaration of competing interest Shiho Furudate and Yuki Kodama are employees of Japan Lifeline Co., Ltd., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Photodynamic therapy (PDT) has been utilized as a promising alternative cancer treatment due to its minimum invasiveness over the years. Exogenous 5-aminolevulinic acid (ALA) triggers protoporphyrin IX (PpIX) accumulation, which happens in cancer cells. However, certain types of cancer exhibit reduced effectiveness in the PpIX accumulation mechanism. This study aimed to determine the effect of ALA-PDT combination with hemin on gastric carcinoma TMK-1 cells., Methods: This study utilized TMK-1 gastric cancer cell line to evaluate PpIX, ROS, and Fe 2+ accumulation following the administration of ALA, hemin, and a combination of ALA and hemin PDT. We also evaluate the mRNA expressions related to iron homeostasis and treatment impacts on cell viability., Results: The co-addition of ALA and hemin PDT for 4 h of treatment resulted in a significant decrease in cell viability by up to 18 %. While ALA-PDT enhanced PpIX metabolism, the addition of hemin influenced both the production of reactive oxygen species (ROS) and cellular iron homeostasis by inducing Fe 2+ accumulation and affecting mRNA levels of IRP, Tfr1, Ferritin, NFS1, and SDHB., Conclusion: These findings suggest that the addition of ALA and hemin enhances phototoxicity in TMK-1 cells. The combination of ALA and hemin with PDT induces cell death, evidenced by increased cytotoxicity properties such as PpIX and ROS, along with significant changes in TMK-1 gastric cancer iron homeostasis. Therefore, the combination of ALA and hemin could be one of the alternatives in photodynamic therapy for cancer in the future., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Periodontitis, a chronic infectious disease leading to gingival atrophy and potential tooth loss through alveolar bone resorption, is closely linked to the oral microbiome. Fusobacterium nucleatum, known to facilitate late-stage bacterial colonization in the oral microbiome, plays a crucial role in the onset of periodontitis. Controlling F. nucleatum abundance is vital for preventing and treating periodontal disease. Photodynamic therapy combined with 5-aminolevulinic acid (ALA-PDT) has been reported to be bactericidal against Pseudomonas aeruginosa and Staphylococcus aureus. We aimed to investigate the bactericidal potential of ALA-PDT against F. nucleatum, which was evaluated by examining the impact of varying 5-ALA concentrations, culture time, and light intensity. After ALA-PDT treatment, DNA was extracted from interdental plaque samples collected from 10 volunteers and sequenced using the Illumina MiSeq platform. To further elucidate the bactericidal mechanism of ALA-PDT, porphyrins were extracted from F. nucleatum following cultivation with 5-ALA and subsequently analyzed using fluorescence spectra. ALA-PDT showed a significant bactericidal effect against F. nucleatum. Its bactericidal activity demonstrated a positive correlation with culture time and light intensity. Microbiota analysis revealed no significant alteration in α-diversity within the ALA-PDT group, although there was a noteworthy reduction in the proportion of the genus Fusobacterium. Furthermore, fluorescence spectral analysis indicated that F. nucleatum produced an excitable photosensitive substance following the addition of 5-ALA. Overall, if further studies confirm these results, this combined therapy could be an effective strategy for reducing the prevalence of periodontitis., Competing Interests: Declaration of Competing Interest T.N. and O.T. signed a joint research agreement with SBI Pharmaceuticals Co., Ltd. relevant to this article., (Copyright © 2023. Published by Elsevier B.V.)

Background: Nodulocystic acne is a severe form of acne, which is commonly treated with oral isotretinoin, hormones, or antibiotics. However, drug therapy often has some side effects and poor compliance. Fire needle combined with 5-aminolevulinic acid photodynamic therapy (ALA-PDT) is a simple, effective, short-term treatment with few adverse reactions, which is expected to be an effective physiotherapy for nodulocystic acne. Moreover, the combination with isotretinoin can reduce the dosage of the drug, thereby reducing the side effects of isotretinoin., Objectives: To evaluate the safety and efficacy of fire-needle pretreated ALA-PDT combined with low-dose isotretinoin in the treatment of severe refractory nodulocystic acne., Methods: This study reported 10 patients with refractory nodulocystic acne who received combined treatment. During the treatment period, all patients received a low dose of oral isotretinoin capsules daily. The acne lesions were pretreated with fire needle before ALA-PDT treatment. The number of acne lesions, including papules, pustules, and nodular cysts, was documented at weeks 0, 2, 4, 8, and 12 to assess the therapeutic efficacy. Concurrently, adverse reactions such as pain, pruritus, and pigmentation changes were recorded and evaluated throughout the treatment course., Results: After combined treatment, all patients achieved good therapeutic effects, with an overall effective rate of 90 % at week 12. After treatment, skin lesions such as nodules, and cysts subsided significantly. The combination therapy has no serious adverse effects and has a favorable safety profile., Conclusion: Fire needle pretreatment ALA-PDT combined with low-dose isotretinoin is effective and safe in the treatment of severe refractory nodular cystic acne, which is worthy of clinical promotion and research., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Acne vulgaris is one of the most prevalent skin disorders; it affects up to 85% of adolescents and often persists into adulthood. Topical 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) provides an alternative treatment for acne; however, its efficacy is greatly undermined by the limited skin permeability of ALA. Herein, biocompatible ionic liquids (ILs) based on aliphatic acid/choline were employed to enhance the dermal delivery of ALA, thereby improving the efficacy of PDT. In addition to the one-step delivery of ALA by utilizing ILs as carriers, a two-step strategy of pretreating the skin with blank ILs, followed by the administration of free ALA, was employed to test the IL-facilitated dermal delivery of ALA in vitro . The cumulative permeation of ALA through the excised rat skin after IL pretreatment was significantly greater than that in the untreated group, the 20% dimethyl sulfoxide (DMSO) penetration enhancer group, and the one-step group. The penetration efficiency was influenced by formulation and treatment factors, including the type of IL, pretreatment duration, water content in the ILs, and concentration of ALA. In rats, IL pretreatment facilitated faster, greater, and deeper ALA-induced protoporphyrin IX (PpIX) accumulation. Moreover, the IL pretreatment regimen significantly improved the efficacy of ALA-based PDT against acne vulgaris in a rat ear model. The model IL choline citrate ([Ch] 3 [Cit] 1 ) had a moderate effect on the skin barrier. Trans-epidermal water loss could be recovered 1 h after IL treatment, but no irritation to the rat skin was detected after 7 days of consecutive treatment. It was concluded that biocompatible IL pretreatment enhances the penetration of ALA and thus facilitates the transformation of PpIX and improves the efficacy of PDT against acne vulgaris.

Objective: The study aimed to compare the clinical efficacy and safety of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) and surgery in treating recurrent cervical high-grade squamous intraepithelial lesions (HSIL) after surgery due to precancerous lesions., Methods: A total of 41 patients with recurrent cervical HSIL after surgery for precancerous lesions were studied retrospectively. Patients underwent ALA-PDT or surgery and were followed up at 3, 6, 9 and 12 months and then every six months after that. Clinical data were collected and the efficacy and safety of the two treatment methods were compared., Results: Of the 41 patients with recurrent cervical HSIL after conization, 15 cases received ALA-PDT and 26 received surgery. At the six-month follow-up, the lesions' complete remission (CR) rate was 93.33 % in ALA-PDT group and 88.46 % in the surgery group. The human papillomavirus (HPV) clearance rates were 66.67 % and 73.08 %, respectively. No significant differences concerning the lesions' CR rate and the HPV clearance rate were observed between the two groups (P>0.05). At the twelve-month follow-up, the HPV clearance rates were 80.00 % and 91.67 %. No significant differences concerning the HPV clearance rate were observed between the two groups (P>0.05). In the surgery group, the HPV clearance rate and the lesions' CR rate were lower in patients over 45 years of age (25.00% vs. 81.82 %, P = 0.031; 50.00% vs. 95.45 %, P = 0.052). During the follow-up, there was no significant difference in the recurrence rate between the two groups (P>0.05). In addition, none of the patients progressed. In women treated with ALA-PDT, there was no vaginal bleeding, and no harmful effects on the cervical organizational structure or functions compared to the surgery group, and two women delivered successfully after ALA-PDT treatment., Conclusions: The efficacy of ALA-PDT was similar to that of surgery in treating recurrent cervical HSIL following surgery, with fewer side effects., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Vaginal intraepithelial neoplasia (VaIN) is a group of diseases of squamous epithelial dysplasia and carcinoma in situ occurring in the vagina, which is associated with high-risk human papillomavirus (HR-HPV) infection., Objectives: To evaluate the efficacy and safety of Carbon dioxide (CO 2 ) laser, 5-aminolevulinic acid photodynamic therapy (PDT) and PDT combined with CO 2 laser pretreatment for VaIN1 with HR-HPV infection, and analyze the factors affecting the clearance of HR-HPV., Methods: Patients with HR-HPV infection and pathological diagnosis of VaIN1 and received laser or PDT or PDT combined with laser pretreatment were recruited. A total of 45 patients received one to three times CO 2 laser (laser Group), 15 patients received three times PDT (PDT Group) and 15 patients received CO 2 laser once and PDT three times (laser + PDT Group). HPV testing, cytology and colposcopy examinations at 3-6 months and 9-12 months after treatment were analyzed to assess the outcomes of the treatment., Results: There was no significant difference in regression rate of VaIN1 among the laser Group, the PDT Group and the laser + PDT Group (3-6 month follow-up: 57.78% vs 73.3% vs 80 %, 9-12 month follow-up: 68.89% vs 80% vs 86.67 %, P>0.05). HR-HPV remission rates were also similar in the three groups (3-6 month follow-up: 26.67% vs 46.67% vs 46.67 %, 9-12 month follow-up: 40 % in all groups, P>0.05). Compared to HR-HPV negative group, patients in the HR-HPV positive group were older and had more pregnancies. Menopause and multiple vaginal lesions were more common in the HR-HPV positive group. Adverse reactions were mild in the PDT Group. The laser Group and the laser + PDT Group had more adverse effects, such as increased vaginal secretion, vaginal bleeding, scarring and local pain., Conclusion: For patients with VaIN1 at risk of progression, ALA-PDT presents itself as a viable choice for those who are well-informed and can consent to its costs and benefits. The addition of CO 2 laser pretreatment may not increase the benefit of ALA-PDT treatment of VaIN1. Older age, menopause, more times of pregnancies, and multiple vaginal lesions might affect HR-HPV regression., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Background: Chronic wounds refer to those that can't reconstruct anatomical and physical functional integrity, and are usually associated with signs of microbial infection. Current therapies include debridement and dressing change, local or systemic application of antibiotics, and medical dressing care, which are not ideal for the healing of chronic wounds., Objective: To explore the efficacy and safety of photodynamic therapy (ALA-PDT) for the treatment of chronic infectious wounds., Materials and Methods: ALA-PDT was used in ten patients with persistent wound infections and systemic complications who did not respond to conventional treatment. 5 % ALA solution was applied to the wound surface after debridement, incubated for 3 h with light protection, and then irradiated with red light for 20 min. This procedure was repeated every two weeks, and any adverse reactions were recorded. After the end of three treatments, the patients were followed up for 3 months., Results: Patients who exhibit resistance to traditional therapies demonstrate a favorable therapeutic outcome with ALA-PDT, although complications may impede wound healing. All participants successfully underwent ALA-PDT treatment and subsequent monitoring, with 90 % achieving complete healing. Common adverse reactions to ALA-PDT encompass treatment-related pain, temporary erythema, and swelling, all of which are well-tolerated by patients without enduring severe consequences., Conclusions: ALA-PDT proves to be an efficacious intervention for managing chronic wounds, irrespective of the presence of localized infections or systemic complications., Competing Interests: Conflict of Interest Disclosures Dr. Rui Yin received the supports by Chongqing medical scientific research project (Joint Project of Chongqing Health Commission and Science and Technology Bureau) (NO. 2022ZDXM014) and the National Natural Science Foundation of China (No. 82172203). No authors hold stock or receive royalties from any companies., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Significance: Photodynamic therapy (PDT) can be targeted toward different subcellular localizations, and it is proposed that different subcellular targets vary in their sensitivity to photobiological damage. Since singlet oxygen ( 1 O 2 ) has a very short lifetime with a limited diffusion length in cellular environments, measurement of cumulative 1 O 2 luminescence is the most direct approach to compare the PDT sensitivity of mitochondria and plasma membrane., Approach: PDT-generated near-infrared 1 O 2 luminescence at 1270 nm was measured together with cell viability for 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) and exogenous PpIX, at different incubation times. Confocal fluorescence microscopy indicated that ALA-induced PpIX (2 h) localized in the mitochondria, whereas exogenous PpIX (1 h) mainly localized to the plasma membrane. Cell viability was determined at several time points during PDT treatments using colony-forming assays, and the surviving fraction correlated well with cumulative 1 O 2 luminescence counts from PpIX in mitochondria and plasmas membrane, respectively., Results: The mitochondria are more sensitive than the plasma membrane by a factor of 1.7., Conclusions: Direct 1 O 2 luminescence dosimetry's potential value for comparing the PDT sensitivity of different subcellular organelles was demonstrated. This could be useful for developing subcellular targeted novel photosensitizers to enhance PDT efficiency., Competing Interests: Declaration of competing interest The authors have declared that there are no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Background: Selective accumulation of photosensitizers into cancerous cells is one of the most important factors affecting photodynamic therapy (PDT) efficacy. 5-aminolevulinic acid (5-ALA) is the precursor of a strong photosensitizer, protoporphyrin-IX; but it has poor permeability into the cells. Folate receptors are overexpressed on the surface of many tumor cells. In the present study, folic acid (FA) and 5-ALA conjugated bismuth oxide nanoparticles were synthesized; and used in PDT, radiotherapy (RT), and concurrent PDT & RT against nasopharyngeal carcinoma (KB cell line)., Methods: The KB cells were incubated with the synthesized nanoparticles (NPs) for 2 h; then illuminated using a custom-made LED lamp at the light dose of 26 J/cm 2 . Irradiation of the cells was carried out using X-ray 6 MV (2 Gy); and synergistic effect of the simultaneous RT and PDT treatments was evaluated using fractional product values. Efficacy of the treatments was determined using MTT and Caspase-3 enzyme activity assays., Results: Targeting of folic acid receptors enables the selective endocytosis of the conjugated NPs. RT results in the presence of Bi 2 O 3 NPs showed a significant radiosensitizer potential of these NPs. Fractional product values of 1.49±0.05, 1.36±0.06, and 1.05±0.06 obtained in the presence of FA-5-ALA conjugated NPs, 5-ALA conjugated NPs, and in the absence of the NPs, respectively. Therefore, simultaneous RT and PDT in the presence of these conjugated NPs is superior to RT in the presence of the NPs., Conclusion: Simultaneous PDT and RT in the presence of FA-5-ALA conjugated bismuth oxide NPs can be introduced as a promising therapeutic approach in controlling KB cancer cells., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Background: Mitochondrial dysfunction is considered an important mechanism in the pathogenesis of various diseases. Therefore, mitochondria are currently being considered as subjects for targeted therapies, particularly, phototherapy using 5-aminolevulinic acid. This study aimed to investigate the activity of mitochondria in cells with different mutation loads., Materials and Methods: The study was conducted using 11 cybrid lines obtained from the THP-1 cell line (a human monocytic leukemia cell line) and platelets of patients with different mitochondrial mutations., Results: Our results illustrate that 5-aminolevulinic acid was metabolized equally in all cell lines, however, there was a significant decrease in mitochondrial potential, which differed among lines., Conclusions: The results of this study can be used to develop a personalized therapeutic approach based on different mitochondrial activities., Competing Interests: The authors declare no conflict of interest., (© 2023 The Author(s). Published by IMR Press.)

Psoriasis does not respond adequately to the monotherapy, tailoring combined strategies for synergistical treatment remains challenging. We fabricated chitosan/hyaluronan nanogels to co-load methotrexate (MTX) and 5-aminoleavulinic acid (ALA), i.e., MTX-ALA NGs, for a combined chemo-photodynamic therapy for psoriasis. Compared with MTX-ALA suspension, the NGs enhanced the penetration and retention of MTX and ALA through and into the skin in vitro and in vivo (p < 0.001). NGs enhanced the cellular uptake (p < 0.001), protoporphyrin IX conversion (p < 0.001), and reactive oxygen species generation (3.93-fold), subsequently exerted the synergistical anti-proliferation and apoptosis on lipopolysaccharide-irritated HaCaT cells with the apoptosis rate of 78.6%. MTX-ALA NGs efficiently ameliorated the skin manifestations and down-regulated the proinflammatory cytokines of TNF-α and IL-17A in imiquimod-induced psoriatic mice (p < 0.001). Importantly, MTX-ALA NGs reduced the toxicities of oral MTX to the liver and kidney. The results support that MTX-ALA NG is a convenient, effective, and safe combined chemo-photodynamic strategy for psoriasis treatment., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: To compare 5-aminolevulinic acid (5-ALA)-mediated photodynamic diagnosis (PDD) with narrow-band imaging (NBI) for cancer detection during transurethral resection of bladder tumour (TURBT)., Methods: Between June 2018 and October 2020, 114 patients and 282 lesions were included in the analysis. Patients were orally administered 5-ALA (20 mg/kg) 2 h before TURBT. The bladder was inspected with white light (WL), PDD, and NBI for each patient, and all areas positive by at least one method were resected or biopsied. The imaging data were then compared to the pathology results., Results: The sensitivities of WL, PDD, and NBI for detecting urothelial carcinoma were 88.1%, 89.6%, and 76.2%, respectively. The specificity, positive predictive value, and negative predictive value for detecting urothelial carcinoma were 47.5%, 80.9%, and 61.3%, respectively, for WL; 22.5%, 74.5%, and 46.2%, respectively, for PDD; and 46.3%, 78.2%, and 43.5%, respectively, for NBI. PDD was significantly more sensitive than NBI for all lesions (p < 0.001) and carcinoma in situ (CIS) lesions (94.6% vs. 54.1%, p < 0.001)., Conclusions: PDD can increase the detection rate of bladder cancer, compared to NBI, by greater than 10%. Therefore, 100% of CIS lesions can be detected by adding PDD to WL., (© 2021. The Author(s).)

Background: To investigate risk factors for orally administered 5-aminolevulinic acid (ALA)-induced hypotension for bladder cancer patients receiving photodynamic diagnosis (PDD)-assisted transurethral resection of bladder tumor (TURBT)., Methods: Patients were categorized into two groups intraoperatively: a hypotensive group (minimum systolic blood pressure (SBP) ≤80 mmHg) and a non-hypotensive group (minimum SBP > 80 mmHg). We examined differences between the hypotensive group and non-hypotensive groups to identify clinical risk of ALA-induced hypotension using multivariate logistic regression analysis and decision tree analysis., Results: Among 282 cases with ALA-PDD-assisted TURBT from three institutions who were screened, 245 patients were included in the final analysis. In total, 156 patients (63.7%) showed any grade of hypotension during ALA-PDD-assisted TURBT. General anesthesia and spinal anesthesia were induced intraoperatively in 113 patients (46.1%) and 132 patients (53.9%), respectively. Median SBP at baseline (before taking ALA) and at the beginning of anesthesia was 127 mmHg (range, 69-186 mmHg) and 124 mmHg (range, 69-186 mmHg), respectively. Median minimum SBP during ALA-PDD-assisted TURBT was 75 mmHg (range, 43-140 mmHg). Multivariate logistic regression analysis revealed that history of hypertension (odds ratio (OR) 7.568, p < 0.05) and general anesthesia (OR 14.435, p < 0.05) as significantly associated with an increased risk of hypotension incidence. Use of calcium antagonist showed significant negative associations with hypotension (OR 0.183, p < 0.05). Decision tree analysis showed presence of general anesthesia, age ≥ 74 years and American Society of Anesthesiologists physical status (ASA-PS) ≥2 as the most important discriminators., Conclusions: General anesthesia and hypertension were independent risk factors related to ALA-induced hypotension. In contrast, use of calcium antagonists was identified as a factor associated with reduced risk of ALA-induced hypotension., (© 2021. The Author(s).)

To treat malignant glioma, standard fractionated radiotherapy (RT; 60 Gy/30 fractions over 6 weeks) was performed post-surgery in combination with temozolomide to improve overall survival. Malignant glioblastoma recurrence rate is extremely high, and most recurrent tumors originate from the excision cavity in the high-dose irradiation region. In our previous study, protoporphyrin IX physicochemically enhanced reactive oxygen species generation by ionizing radiation and combined treatment with 5-aminolevulinic acid (5-ALA) and ionizing radiation, while radiodynamic therapy (RDT) improved tumor growth suppression in vivo in a melanoma mouse model. We examined the effect of 5-ALA RDT on the standard fractionated RT protocol using U251MG- or U87MG-bearing mice. 5-ALA was orally administered at 60 or 120 mg/kg, 4 h prior to irradiation. In both models, combined treatment with 5-ALA slowed tumor progression and promoted regression compared to treatment with ionizing radiation alone. The standard fractionated RT protocol of 60 Gy in 30 fractions with oral administration of 120 and 240 mg/kg 5-ALA, the human equivalent dose of photodynamic diagnosis, revealed no significant increase in toxicity to normal skin or brain tissue compared to ionizing radiation alone. Thus, RDT is expected to enhance RT treatment of glioblastoma without severe toxicity under clinically feasible conditions.

Background: Tumors that take up and metabolize 5-aminolevulinic acid emit bright pink fluorescence when illuminated with blue light, aiding surgeons in identifying the margin of resection. The adoption of this method is hindered by the blue light illumination, which is too dim to safely operate under and therefore necessitates switching back and forth from white-light mode. The aim of this study was to examine the addition of an optimized secondary illuminant adapter to improve usability of blue-light mode without degrading tumor contrast., Methods: Color science methods were used to evaluate the color of the secondary illuminant and its impact on color rendering index as well as the tumor-to-background color contrast in data collected from 7 patients with high-grade gliomas (World Health Organization grade III and IV). A secondary illuminant adapter was built to provide 475-600 nm light the intensity of which can be controlled by the surgeon and was evaluated in 2 additional patients., Results: Secondary illuminant color had opposing effects on color rendering index and tumor-to-background color contrast; providing surgeon control of intensity allows this trade-off to be balanced in real time. Demonstration in 2 high-grade glioma cases confirms this, showing that additional visibility adds value when intensity can be controlled by the surgeon., Conclusions: Addition of a secondary illuminant may mitigate surgeon complaints that the operative field is too dark under the blue light illumination required for 5-aminolevulinic acid fluorescence guidance by providing improved color rendering index without completely sacrificing tumor-to-background color contrast., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Sono-photodynamic therapy is a promising anticancer technique based on the combination of sonodynamic and photodynamic therapy to improve the cancer treatment effectiveness. This study was aimed at analyzing the effects of the sono-photodynamic (SPD) activity on protoporphyrin IX (PpIX) solution and PpIX-loaded rat liver. In vitro, PpIX 5 μM solutions were irradiated with light (635 nm, 30-50 mW/cm 2 ), ultrasound (1 MHz, 1-2 W/cm 2 ) and both. The PpIX absorption spectra recorded over exposure time revealed that the PpIX decay rate induced by SPD activity (combined irradiation) was approximately the sum of those induced by photodynamic and sonodynamic activity. In vivo, rats were intraperitoneally injected with 5-aminolevulinic acid at the dose of 500 mg/kg weight. After 3 h of injection, the PpIX-loaded livers were irradiated with light (635 nm, 180 ± 9 J/cm 2 ), ultrasound (1.0 MHz, 770 ± 40 J/cm 2 ) and both using a single probe capable of illuminating and sonicating the liver simultaneously. After 30 h, the liver damage induced by each protocol was analyzed histologically. It was found that a greater necrosis depth was induced by the SPD activity. These results suggest that the SPD activity could improve the PpIX decay rate and have greater scope than photodynamic or sonodynamic activity. Further studies should be performed to gain a better understanding of this protocol., Competing Interests: Conflict of interest disclosure The authors declare that they have no conflict of interest., (Copyright © 2020 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Introduction: Radiodynamic therapy (RDT) involves administration of a radiosensitizing agent and its subsequent activation by ionizing radiation for destruction of neoplastic cells., Materials and Methods: A comprehensive evaluation of the literature was performed to review the history of RDT using porphyrins for solid tumors, the cellular mechanisms of action, immunomodulatory effects, and both preclinical and clinical studies for use in high-grade gliomas (HGGs). This manuscript was prepared in accordance with the PRISMA guidelines., Results: A total of 271 articles were considered for initial review. After removal of duplicates, articles not unrelated to specific topic, and exclusion of commentary articles, a total of 11 articles were subject to full analysis that included in vivo, in vitro, and human studies. Porphyrins such as 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) selectively accumulate in neoplastic cells and are currently used for fluorescent-guided surgical resection and photodynamic therapy (PDT) of HGG and other brain tumors. 5-ALA is also shown to act as a radiosensitizer by increasing oxidative stress in neoplastic cell mitochondria and enhancing the host immune response. Postoperative radiation therapy is currently the standard of care for treatment of HGG., Conclusion: RDT remains a promising adjuvant therapy for HGGs and requires further investigation. Clinical trials of 5-ALA RDT for HGG are needed to evaluate the optimum timing, dosing and effectiveness., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Photodynamic therapy (PDT) is an effective treatment for actinic keratoses (AK). PDT is usually performed with occlusion of the photosensitizer prior to subsequent illumination., Objectives: This study aimed to compare the efficacy and tolerability of occlusive versus non-occlusive application of a 5-aminolevulinic gel (BT-200 ALA) for PDT of multiple AK on the scalp or face., Methods: Prospective, investigator-blinded, within-patient comparison study on 45 patients. PDT with occlusion of ALA was performed in a target area on one randomized side of the scalp or face. One week later a contralateral target area received the same treatment except that no occlusion of the ALA gel was performed. 3 and 6 months after PDT, the clearance rate of a predetermined target lesion and the total clearance rate of all AK within the treated areas were determined. PDT-induced pain and skin phototoxicity and cosmetic outcome were also recorded., Results: Clearance rate of the target AK and total AK clearance rate at 3 months after PDT was 88.4% and 90.6% for occlusive PDT and 58.1% (P = .001) and 70.4% (P = .04) for non-occlusive PDT. The corresponding values at 6 months after PDT were 69.7% and 72.1% for occlusive PDT and 30.2% (P < .001) and 35.6% (P = .001) for non-occlusive PDT. Pain score and skin phototoxicity were significantly higher after occlusive ALA application. No difference was observed with respect to cosmetic outcome., Conclusions: Occlusive application of ALA significantly improves the efficacy of PDT but is associated with more pain and increased phototoxicity., (© 2020 The Authors. Photodermatology, Photoimmunology & Photomedicine Published by John Wiley & Sons Ltd.)

Background: Photodynamic therapy with 5-aminolevulinic acid (5-ALA PDT) is a promising novel therapeutic approach in the therapy of malignant brain tumors. 5-ALA occurs as a natural precursor of protoporphyrin IX (PpIX), a tumor-selective photosensitizer. The ATP-binding cassette transporter ABCG2 plays a physiologically significant role in porphyrin efflux from living cells. ABCG2 is also associated with stemness properties. Here we investigate the role of ABCG2 on the susceptibility of glioblastoma cells to 5-ALA PDT., Methods: Accumulation of PpIX in doxycycline-inducible U251MG glioblastoma cells with or without induction of ABCG2 expression or ABCG2 inhibition by KO143 was analyzed using flow cytometry. In U251MG cells, ABCG2 was inducible by doxycycline after stable transfection with a tet-on expression plasmid. U251MG cells with high expression of ABCG2 were enriched and used for further experiments (sU251MG-V). PDT was performed on monolayer cell cultures by irradiation with laser light at 635 nm., Results: Elevated levels of ABCG2 in doxycycline induced sU251MG-V cells led to a diminished accumulation of PpIX and higher light doses were needed to reduce cell viability. By inhibiting the ABCG2 transporter with the efficient and non-toxic ABCG2 inhibitor KO143, PpIX accumulation and PDT efficiency could be strongly enhanced., Conclusion: Glioblastoma cells with high ABCG2 expression accumulate less photosensitizer and require higher light doses to be eliminated. Inhibition of ABCG2 during photosensitizer accumulation and irradiation promises to restore full susceptibility of this crucial tumor cell population to photodynamic treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: The usefulness of 5-aminolevulinic acid (5-ALA)-mediated fluorescence-guided surgery (FGS) in meningiomas is intensely discussed. However, data about kinetics of 5-ALA and protoporphyrin (Pp) IX in meningiomas are lacking., Methods: As the first study so far, we performed longitudinal intraoperative real-time ex situ measurements of fluorescence intensity and PpIX concentrations during FGS of ten benign and two atypical meningiomas. Kinetics were subsequently compared with data from 229 glioblastomas., Results: Spectroscopy revealed fluorescence (median 2945.65 a.u.) and PpIX accumulation (median 18.31 μg/ml) in all 43 analyzed samples. Fluorescence intensity (2961.50 a.u. vs 118.41 a.u.; p < .001) and PpIX concentrations (18.72 μg/ml vs .98 μg/ml; p < .001) were higher in samples with (N = 30) than without (N = 2) visible intraoperative tumor fluorescence. ROC curve analyses revealed a PpIX cut-off concentration of 3.85 μg/ml (AUC = .992, p = .005) and a quantitative fluorescence cut-off intensity of 286.73 a.u. (AUC = .983, p = .006) for intraoperative visible tumor fluorescence. Neither fluorescence intensity (p = .356) nor PpIX (p = .631) differed between atypical and benign meningiomas. Fluorescence and PpIX peaked 7-8 h following administration of 5-ALA. Meningiomas displayed a higher fluorescence intensity (p = .012) and PpIX concentration (p = .005) than glioblastomas 5-6 h after administration of 5-ALA. Although fluorescence was basically maintained, PpIX appeared to be cleared faster in meningiomas than in glioblastomas., Conclusions: Kinetics of PpIX and fluorescence intensity differ between meningiomas and glioblastomas in the early phase after 5-ALA administration. Modification of the timing of drug administration might impact visibility of intraoperative fluorescence and helpfulness of FGS and should be investigated in future analyses.

Photodynamic therapy induced by protoporphyrin IX (PpIX) is widely used to treat precancerous skin lesions. The penetration depth of the prodrug 5-aminolevulinic acid (5-ALA) using topical application is currently limited, which hampers the production of PpIX in deep seated lesions. To enhance 5-ALA delivery in deep skin layers, a soluble microneedles patch (MN-patch) containing 5-ALA has been successfully developed by using a fast solvent casting molding method which could be easily up-scaled. The shape, number and height of the needles have been designed according to the medical application and the mechanical strain necessary for skin insertion. Hyaluronic acid (HA) has been chosen as the needle materials due to its biocompatibility, fast solubility and biodegradation and was mixed with 5-ALA prior to casting. HA-based MN-patch containing 5-ALA have exhibited mechanical properties enabling a good insertion into the skin without significant damages to MN. Interactions between HA and 5-ALA were evaluated by Fourier transform infrared spectroscopy (FTIR) and carbon nuclear magnetic resonance ( 13 C NMR), stability of 5-ALA in the MN-patch was monitored by proton nuclear magnetic resonance ( 1 H NMR) and exhibited a good stability over 5 months after manufacturing. Dissolution rate of the whole patch was completed in 1 hour in ex vivo rat skin without cytotoxicity. Overall, the MN-patch can be a promising technique to enhance 5-ALA penetration and produce PpIX in deeper skin lesions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

New diagnostic techniques based on photodynamic medicine, such as near-infrared fluorescence using indocyanine green (NIR-ICG) and 5-aminolevulinic acid-mediated photodynamic diagnosis (ALA-PDD), are aiding navigation tasks across various fields of surgery. Specifically, NIR-ICG is being used for the intraoperative identification of sentinel lymph nodes or blood vessels in organ resection and for blood flow evaluation in surgery. These ICG-fluorescent imaging techniques could provide an additional and potentially valuable way to identify vascular and lymphatic structures in surrounding tissue. 5-Aminolevulinic acid is a precursor of a photosensitizing substance with affinity for tumors; thus, diagnostic laparoscopy using ALA-PDD in combination should improve the accuracy of detecting peritoneal dissemination in patients with advanced gastric cancer. The ability to overlay fluorescent imaging with conventional color images in real time using ALA-PDD and NIR with ICG would be of immense benefit to surgeons, providing good visualization and detection of target lesions not seen with the naked eye. A multi-center clinical study examining the safety and efficacy of ALA-PDD during laparoscopic examination for patients with advanced gastric cancer is currently underway in the form of doctor-initiated trials, and further verification studies will be conducted. Such imaging capability could have broad potential across cancer and vascular surgery.

Background: 5-aminolevulinic acid (5-ALA) has been utilized for cancer diagnosis as a fluorescence probe. We have reported the feasibility of 5-ALA-induced protoporphyrin IX (PpIX) fluorescence for detecting lymph node (LN) metastasis in gastrointestinal malignancies. However, a major barrier to the fluorescence diagnosis has been that the evaluation has been highly dependent on the observers. In this study, we examined the validity of a developed device for automated detection without subjectivity., Methods: Gastric cancer patients who received oral administration of 5-ALA (20 mg/kg) prior to surgery were enrolled. For a total of 323 LNs obtained from 64 patients, the diagnostic results of the device were compared to those of conventional histopathological examination based on hematoxylin-and-eosin-stained slides. The accuracy with the device was compared to that of stereoscopic detection with conventional fluorescence microscopy for 211 LNs from 42 patients. We used two types of image processing that we previously developed to eliminate autofluorescence of background tissues: differential and ratio methods., Results: For detection of metastasis in 323 LNs, the areas under the receiver operating characteristic curves with the differential method and ratio method were 0.921 and 0.909, respectively. The sensitivity, specificity, and accuracy with the differential method were 78.0%, 96.8%, and 94.4%; while those with the ratio method were 78.0%, 96.1%, and 93.8%, respectively. In 211 LN analysis, the diagnostic accuracy with the device was comparable to that of stereoscopic examination., Conclusion: Our device for automated detection of LN metastasis using 5-ALA can be a useful tool for intraoperative diagnosis.

Bacterial photodynamic inactivation (PDI) employing endogenous production of porphyrins from 5-aminolevulinic acid (ALA) - named ALA-PDI-, is a new promising tool to achieve bacteria control in non-spread infections. The technique combines the action of the porphyrins acting as photosensitisers with light, to produce reactive oxygen species to target the pathogen. To date, some clinical applications of ALA-PDI have been reported although variable responses ranging from total eradication to absence of photokilling were found. ALA-PDI conducted at suboptimal conditions may lead to misleading results and the complexity of haem synthesis in bacteria hinders the optimization of the treatment. The present work aimed to gain insight on the variables affecting ALA-PDI in Gram-positives and Gram-negatives bacteria growing on planktonic and biofilm cultures and to correlate the degree of the response with the amount and type of porphyrin synthesised. Staphylococcus epidermidis and Escherichia coli clinical isolates and Pseudomonas aeruginosa ATCC27853 and Staphylococcus aureus ATCC25923 strains were utilised, and the optimal conditions of concentration and time exposure of ALA, and light dose were set. In both Gram-positive species analysed, a peak of porphyrin synthesis was observed at 1-2 mM ALA in biofilm and planktonic cultures, which fairly correlated with the decrease in the number of CFU after PDI (5 to 7 logs) and porphyrin content was in the same order of magnitude. In addition, ALA-PDI was similarly effective for planktonic and biofilm S. aureus cultures, and more effective in S. epidermidis planktonic cultures at low light doses. Beyond a certain light dose, it was not possible to achieve further photosensitization. Similarly, a plateau of cell death was attained at a certain ALA incubation time. Accumulation of hydrophilic porphyrins at longer incubation periods was observed. The proportion of porphyrins changed as a function of ALA concentration and incubation time in the Gram-positive bacteria, though we did not find a clear correlation between the porphyrin type and PDI response. As a salient feature was the presence of isococroporphyrin isoforms in both Gram-positive and Gram-negative bacteria. Gram-negative bacteria were quite refractory to the treatment: P. aeruginosa was slightly inactivated (4-logs reduction) at 40 mM ALA, whereas E. coli was not inactivated at all. These species accumulated high ALA quantities and the amount of porphyrins did not correlate with the degree of photoinactivation. Our microscopy studies show that porphyrins are not located in the envelopes of Gram-negative bacteria, reinforcing the hypothesis that endogenous porphyrins fail to attack these structures., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background/aim: We evaluated urinary levels of porphyrin metabolites, such as uroporphyrin (UP) and coproporphyrin (CP), after 5-Aminolevulinic acid (ALA) administration in patients with or without pancreatic cancer (PaC)., Patients and Methods: Sixty-seven subjects with PaC, 11 with pancreatitis, and 9 with normal pancreas (NP) were enrolled. Urine samples from all subjects were collected prior to ALA administration and at more than 4 hours after ALA administration. We measured the urinary levels of UP and CP by high-performance liquid chromatography analysis., Results: The PaC group showed significantly higher UP levels compared to NP groups (104.9 nmol/g Cre vs. 53.4 nmol/g Cre, p=0.014). Moreover, PaC patients with long-term survival had significantly lower urinary levels of UP at diagnosis (98.8 nmol/gCre) than the short-term survival group (125.2 nmol/gCre) (p=0.042)., Conclusion: The urinary levels of UP after ALA administration might serve as a promising biomarker for diagnosis and prognosis prediction of PaC., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

The complex biology of glioma compromises therapeutic efficacy and results in poor prognosis. Photodynamic therapy (PDT) has emerged as a promising modality for localized tumor ablation with limited damage to healthy brain tissues. However, low photosensitizer concentration and hypoxic microenvironment in glioma tissue hamper the practical applications of PDT. To address the challenges, biocompatible periodic mesoporous organosilica coated Prussian blue nanoparticles (PB@PMOs) are constructed to load a biosafe prodrug 5-aminolevulinic acid (5-ALA), which is pronouncedly converted to protoporphyrin IX (PpIX) in malignant cells. PB@PMO-5-ALA induces a higher accumulation of PpIX in glioma cells compared to free 5-ALA. Meanwhile, the PB@PMOs, with a mean edge length of 81 nm and good biocompatibility, effectively decompose hydrogen peroxide to oxygen in a temperature-responsive manner. Oxygen supply further contributes to the promotion of 5-ALA-PDT. Thus, the photodynamic effect of PB@PMO-5-ALA is significantly improved, imposing augmented cytotoxicity to glioma U87MG cells. Furthermore, ex vivo fluorescence imaging elucidates the tumor PpIX increases by 75% in PB@PMO-5-ALA treated mice than that in 5-ALA treated ones post 12 h injection. Magnetic resonance imaging (MRI) and iron staining strongly demonstrate the accumulation of PB@PMO-5-ALA in glioma tissues with negative contrast enhancement and blue staining deposits, respectively. The nanoparticle accumulation and high PpIX level collaboratively enhance PDT efficacy through PB@PMO-5-ALA, which efficiently suppresses tumor growth, providing a promising option with safety for local glioma ablation., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To investigate the diagnostic accuracy of 5- aminolevulinic acid-mediated photodynamic diagnosis (ALA-PDD) for upper urinary tract tumor (UTUC) including carcinoma in situ (CIS) lesions using flexible fluorescence ureterorenoscopy., Methods: A solution of ALA was orally administrated at 20 mg/kg body weight at 3 h prior to surgery. Fluorescence observation was carried out with IMAGE1S OPAL1 PDD system. Positive lesions that were identified as abnormal changes under white light and/or blue light were biopsied, followed by cold-cup biopsy of negative lesions that were normal-looking mucosa under white light and/or blue light. Diagnostic accuracy was analysed by comparing ureterorenoscopic observations under white light or blue light with pathological analysis results., Results: A total of 31 biopsy specimens were obtained from 10 patients. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PDD to detect UTUC was 100 %, 50 %, 52.4 % and 100 %, respectively. The sensitivity of PDD ureterorenoscopy was significantly higher than that of white light ureterorenoscopy by statistics (p < 0.05). Especially, 5 CIS lesions were detected only by ALA-PDD ureterorenoscopy (p < 0.05). Of 10 patients, one patient (10 %) experienced hypotension during the ALA-PDD., Conclusions: ALA-PDD for UTUC is a feasible and safe techniques with acceptable adverse events. Additional advantage of ALA-PDD for UTUC is the high sensitivity to detect CIS lesions with blue light mode., Competing Interests: Declaration of Competing Interest 5-aminolevulinic acid was provided by SBI Pharma CO., Ltd., (Copyright © 2019 The Author(s). Published by Elsevier B.V. All rights reserved.)

The effect of 5-aminolevulinic acid (5-ALA) on a postoperative increase in liver enzymes (PILE) has not been clearly investigated in patients with elevated preoperative liver enzymes. The aim of this study was to evaluate the safety of 5-ALA in brain tumor patients with elevated preoperative liver enzymes by investigating the incidence, severity, and duration of PILE. This retrospective study was conducted in patients with a brain tumor who received 5-ALA preoperatively and had a preoperative increase in liver enzymes. Laboratory data on serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin (TB) levels were collected preoperatively and through postoperative day (POD) 30. The incidence and severity of PILE was evaluated based on the Common Terminology Criteria for Adverse Events. Among 134 patients, 61 (45.5%) developed 97 episodes (grade 1/2/3: 80/10/7) of PILE. Postoperative increases in ALT, AST, ALP, and TB were observed in 41 (30.6%), 33 (24.6%), 6 (4.5%), and 17 (12.7%) patients respectively. Five (3.7%) and two (1.5%) patients showed grade 3 increases in ALT and AST respectively. The maximum liver enzyme levels shown in 97 episodes resolved to preoperative baseline or normal (n = 70), grade 1 (n = 24), and grade 2 (n = 3) levels within POD 30. The incidence of PILE after 5-ALA-guided brain tumor surgery in patients with increased preoperative liver enzymes was 45.5%. However, most PILEs were temporary and the incidence of severe PILE was low, suggesting that administering 5-ALA is relatively safe even in patients with elevated preoperative liver enzymes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: 5-aminolevulinic acid (5-ALA) use is well established in the resection of adult high-grade gliomas. There is growing interest in its usefulness in the paediatric population. The potential benefit of 5-ALA-guided resection motivated our unit to offer the established adult protocol as off-label use., Objective: to determine if 5-ALA guided resection was routinely useful and offered increased gross total resection (GTR) results., Methods: Nineteen patients harbouring a posterior fossa tumour suggestive of either an ependymoma or medulloblastoma (MB) underwent surgery between January 2018 and October 2019. The mean age was 5 years (range 2-12 years). A dose of 20 mg/kg of 5-ALA (Gliolan®) was given 4 h preoperatively. Intraoperatively, the tumours were viewed under violet-blue light and the presence of fluorescence was recorded. Fluorescence status was compared with histopathological classification and grade, Ki-67 index, GTR rate, and a subjective determination of "usefulness" was determined., Results: The case series included ependymoma grade II (n = 6), ependymoma grade III (n = 4), and MB grade IV (n = 9). For the combined cohort, the strong fluorescence rate was 68% (n = 13), the heterogenous fluorescence rate was 26% (n = 5), and the completely negative fluorescence rate was 5% (n = 1). The strong fluorescence rate of 90% found in the combined ependymoma group compared to the 45% strong fluorescence rate in the MB group was statistically significant (p = 0.05). Within the MB group the Ki-67 index was found to be significantly higher in the strongly fluorescent group as opposed to the patchy or non-fluorescent group (77.5 vs. 40%, p = 0.016). Fluorescence was determined to be useful in 63% of all cases. There was no significant relationship between fluorescence and GTR. The relationship between perceived usefulness and resection was not statistically significant. No adverse drug reactions were recorded., Conclusion: This case series adds to the growing body of evidence demonstrating the safety of 5-ALA in the paediatric population. 5-ALA guided resection was found to be useful in the majority of cases but this did not correlate with GTR status. Ependymomas reliably fluoresce in 90% of cases, and 5-ALA-guided resection should be considered when a preoperative diagnosis of ependymoma is suspected., (© 2020 S. Karger AG, Basel.)

Interstitial photodynamic therapy (iPDT) with 5-aminolevulinic acid (ALA) is a possible alternative treatment for malignant brain tumors. Further evaluation is, however, required before it can be clinically applied. Computational simulation of the photophysical process in ALA-iPDT can offer a quantitative tool for understanding treatment outcomes, which depend on various variables related to clinical treatment conditions. We propose a clinical simulation method of ALA-iPDT for malignant brain tumors using a singlet oxygen (O1 2 ) model and O1 2 threshold to induce cell death. In this method, the amount of O1 2 generated is calculated using a photosensitizer photobleaching coefficient and O1 2 quantum yield, which have been measured in several previous studies. Results of the simulation using clinical magnetic resonance imaging data show the need to specify the insertion positions of cylindrical light diffusers and the level of light fluence. Detailed analysis with a numerical brain tumor model demonstrates that ALA-iPDT treatment outcomes depend on combinations of photobleaching and threshold values. These results indicate that individual medical procedures, including pretreatment planning and treatment monitoring, will greatly benefit from simulation of ALA-iPDT outcomes.

Background: Photodynamic therapy (PDT) and diagnosis (PDD) using 5-aminolevulinic acid (ALA) to control the production of an intracellular photosensitizer, protoporphyrin IX (PpIX), are in common clinical use. Although various studies have been published regarding cell death analysis after photoirradiation by ALA-PDT, the changes in gene expressions induced by it are yet unclear. Here, we focused on studying gene expression and cell proliferation changes in cancer cells that survive photoirradiation., Methods: HEK293 human embryonic kidney cells, MKN45 human gastric cells, and PC-3 human prostate cancer cells were selected for this research. Cell viability was measured using trypan blue and MTT assays. ALA-PDT experiments were performed using a calibrated LED irradiation module. Furthermore, mRNA and protein gene expression analysis were performed using our previously reported methods., Results: mRNAs of PAI-1, HO-1, and p21 were upregulated after photoirradiation of HEK293, which was suppressed by N-acetyl-L-cysteine, a reactive oxygen species (ROS) scavenger. Primer array results in PC-3 cells and p21 and Ki-67 expression results in both PC-3 and MKN45 cells suggested that photoirradiation suppressed cell proliferation. Cell numbers post-photoirradiation revealed that the proliferation of surviving cells was suppressed in PC-3 and MKN45 cells., Conclusion: ALA-PDD or ALA-PDT can result in rapid ROS-induced cell death and may decrease long-term recurrence rates through several pathways including the HO-1/p21 pathway., (Copyright © 2019. Published by Elsevier B.V.)

The emergence of drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), has brought great difficulties to clinical treatment. Antibacterial photodynamic therapy (aPDT) is a new non-antibiotic treatment strategy for a variety of drug-resistant bacteria. However, there are few studies on the antimicrobial mechanism of a PDT mediated by 5-aminolevulinic acid (ALA-PDT) for MRSA. In this study, we observed the bactericidal effect of ALA-PDT on MRSA. We found that ALA-PDT had the strongest bactericidal effect when ALA was at 0.05 mM, and the bactericidal activity of aPDT increased with the increase of light dose. MRSA was almost completely eliminated at 0.05 mM and 384 Jcm -2 . In addition, the bactericidal morphology was also observed under a fluorescence microscope using a LIVE/DEAD® BacLight™ Bacterial Viability Kit and an electron microscope. It was also found that proteins and DNA were damaged by ALA-PDT. Finally, the transcription level of the specific gene of MRSA, nuc, was decreased by 0.74-fold (P < 0.05) after ALA-PDT treatment by qRT-PCR analysis. The findings suggest that ALA-PDT can effectively inhibit MRSA by damaging cell membrane, cytoplasm, proteins and nucleic acid., (Copyright © 2019. Published by Elsevier B.V.)

5-Aminolevulinic acid (5-ALA) and its two ester derivatives (5-ALA-OMe and 5-ALA-OHex) have been approved for photodiagnosis and photodynamic therapy (PDT) of tumors in the clinical. However, their pharmacological activities are limited by their instability under physiological conditions and lack of tumor selectivity. With the aim to overcome these shortcomings, a glutathione-responsive 5-ALA derivative (SA) was designed based on the fact that many types of tumor cells have higher intracellular glutathione level than normal cells. SA was synthesized by masking the 5-amion group of 5-ALA methyl ester (5-ALA-OMe) with a self-immolative disulfide linker. Compared with 5-ALA and 5-ALA-OMe, SA exhibited higher stability under physiological conditions, and it can efficiently release the parent compound 5-ALA-OMe in response to glutathione. In tumor cells, SA displayed excellent protoporphyrin IX (PpIX) production activity at low concentrations while 5-ALA and 5-ALA-OMe were ineffective at the same concentration. The SA-induced PpIX production was positively correlated with the intracellular glutathione level, and SA exhibited enhanced phototoxicity due to its excellent PpIX generation activity. This study indicates that modification of the amino group in 5-ALA derivatives with a self-immolative disulfide linker is an effective strategy to improve their chemical stability and pharmacological activities, and SA is a potential photosensitizer for photodiagnosis and PDT of tumors., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Objective: To analyze perioperative blood pressure in patients undergoing transurethral resection of bladder tumor with photodynamic diagnosis., Methods: A total of 109 consecutive patients who underwent photodynamic diagnosis-assisted transurethral resection of bladder tumor at Kanazawa University, Kanazawa, Ishikawa, Japan, were included in this study and considered as the photodynamic diagnosis group. Clinical data were collected, and perioperative systolic bladder pressure and vasopressor usage were analyzed. In contrast, consecutive patients who previously underwent conventional transurethral resection of bladder tumor (without the use of oral 5-aminolevulinic acid) were used as the control group., Results: The systolic blood pressure before anesthesia, lowest systolic blood pressure from the anesthesia induction to the start of operation and lowest systolic blood pressure during operation were significantly lower in the photodynamic diagnosis group. The rate of vasopressor use was significantly higher in the photodynamic diagnosis group. On multivariate analysis, we found that general anesthesia and regular use of renin-angiotensin system inhibitor were associated with an increased risk of hypotension (lowest systolic blood pressure from the anesthesia induction to the start of operation <80 mmHg)., Conclusions: Oral intake of 5-aminolevulinic acid can obviously cause a drop in intraoperative blood pressure in patients undergoing transurethral resection of bladder tumor. Therefore, urologists and anesthesiologists should consider withdrawal of renin-angiotensin system inhibitors and monitor the blood pressure during photodynamic diagnosis-assisted transurethral resection of bladder tumor., (© 2019 The Japanese Urological Association.)

Objective: Extent of resection of glioblastoma is an important predictor for overall survival, and 5-aminolevulinic acid fluorescence-guided surgery can improve outcomes. However, the technique requires the installation of a blue light module on operative microscopes and may be cost prohibitive. A novel and economical blue light-emitting headlamp was designed, and its clinical utility was explored., Methods: A remote-controlled dual light emitting diode headlamp system was constructed with 1 diode emitting white light and the other blue. Spectrographic analysis of the blue light emitted from a commercial operative microscope and the headlamp was performed. A comparative evaluation of the 2 illumination systems was conducted for 3 patients who underwent craniotomy for glioblastoma resection. Histologic examination of the fluorescing tissue detected by the headlamp was performed, and the extent of resection was assessed by postoperative day 1 magnetic resonance imaging., Results: Spectrography of blue light emitted from the headlamp system was wavelength specific with a single emission peak at 416 nm and a linewidth of 35 nm. In contrast, blue light from the microscope (peak: 426 nm) had a wider linewidth of 54 nm and was not wavelength specific with additional infrared radiation detected. Gross or near-total resection of contrast-enhancing glioblastoma was performed for all 3 patients. Intraoperatively, comparable tumor fluorescence was observed under microscope and headlamp blue light illumination. Histologic examination of tissue fluorescing under headlamp blue light confirmed the presence of glioblastoma., Conclusions: This novel proof-of-concept blue light-emitting headlamp device may offer an opportunity for institutions with limited resources to implement 5-aminolevulinic acid fluorescence-guided glioblastoma resections., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Thiosemicarbazone derivatives are known for their broad biological activity including their antitumor potency. The aim of the current study was to examine the effect of a novel series of non-toxic iron chelators on the accumulation of protoporphyrin IX after external 5-aminolevulonic acid administration. From this series we selected one the most promising derivative which causes a pronounced increase in the concentration of protoporphyrin IX. The increase of the photosensitizer concentration is necessary for the trigger the efficient therapeutic effect of the photodynamic reaction. For selected compound 2 we performed an examination of a panel of the genes that are involved in the heme biosynthesis and degradation. Results indicated the crucial roles of ferrochelatase and heme oxygenase in the described processes. Surprisingly, there was a strict dependence on the type of the tested cell line. A decrease in the expression of the two aforementioned enzymes after incubation with compound 2 and 5-aminolevulonic acid is a commonly known fact and we detected this trend for the MCF-7 and HCT 116 cell lines. However, we noticed the upregulation of the tested targets for the Hs683 cells. These unconventional results prompted us to do a more in-depth analysis of the described processes. In conclusion, we found that compound 2 is a novel, highly effective booster of photodynamic therapy that has prospective applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: 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., Method: 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., Results: 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., Conclusion: 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., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Surgical resection for atypical polypoid adenomyoma (APA) is an option for fertility preservation. Due to the high recurrence rate of APA, studies have been conducted to improve total resection of tumors. Photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) improves tumor resection, but this has not been applied for APA. The patient was 35-year-old. After initial treatment, the APA lesion did not disappear. We performed hysteroscopic tumor resection using 5-ALA-PDD. Only one PDD-positive lesion was found and histopathologically diagnosed as APA. Other areas were PDD-negative and showed no histopathologic APA or malignant findings. This is the first report of hysteroscopic 5-ALA-PDD for APA. This method makes it easy to identify morbid lesions, and may lead to improved total resection and decreased recurrence., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Cutaneous warts are an extremely common problem, whose eradication can be challenging. Topical PDT involves applying a porphyrin precursor, 5-aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) to the affected area. ALA-PDT has been well documented to be successful in the treatment of recalcitrant warts. PDT has a limited role in the treatment of thicker lesions because the photosensitizer does not penetrate keratotic lesions well, though this is vehicle dependent., Objective: The aim of this study was to evaluate the efficacy and safety of curettage + microneedling + ALA-PDT for the treatment of resistant acral warts. We hypothesized that microneedling may increase the efficacy of PDT, providing a channel to deliver the ALA to deeper areas of warts., Methods: Our study was carried out between November 2017 and July 2018. Eligible participants had one or more resistant plantar or palmar warts. Thirteen patients were recruited. They underwent a thorough curettage, followed by the application of 5-ALA 10% cream on the wart, and by microneedling. Later, the pricked skin was covered for three hours by an occlusive polyurethane dressing, and finally irradiated with a red-light source. Patients performed one session every three weeks for a total of three cycles., Results: After 3 treatments of curettage + microneedling + ALA-PDT, 11 patients (84.6%) showed complete remission (defined as complete disappearance of their warts). One patient (7.7%) showed partial remission (defined as greater than 50% decrease in the wart area) after 3 sessions; this patient needed other 2 sessions to achieve complete remission. The mean follow-up period after healing was 4.3 months. Adverse effects were recorded., Conclusion: We have demonstrated, for the first time to our knowledge, that the combination of curettage + microneedling + topical ALA-PDT may offer an effective and safe alternative for the treatment of acral resistant warts, even when PDT alone has already been insufficient., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Photodynamic therapy (PDT) is a cancer treatment involving the generation of reactive oxygen species (ROS) by laser irradiation of porphyrins that accumulate in cancer tissues. 5-aminolevulinic acid (ALA), a porphyrin precursor, is often used as a photosensitizer. ALA is imported into cells via peptide transporter 1 (PEPT1), and porphyrin is exported via ATP-binding cassette member 2 of subfamily G (ABCG2). Thus, cancer cell-specific porphyrin accumulation involves regulation of both transporters to enhance the ALA-PDT effect. We reported previously that mitochondrial ROS (mitROS) upregulated PEPT1 expression and downregulated ABCG2 expression. Therefore, we propose that increasing mitROS production will enhance ALA-PDT cytotoxicity. Cisplatin is a chemotherapeutic drug that induces intracellular ROS generation. In this study, we investigated whether cisplatin-increased mitROS production in gastric cancer cell lines (RGK36 and RGK45) enhanced the cytotoxicity of ALA-PDT by regulation the expression of both PEPT1 and ABCG2. The results showed that cisplatin increased intracellular mitROS production in cancer but not normal cells (RGM1). PEPT1 was upregulated and ABCG2 downregulated in cancer cells treated with cisplatin. Moreover, intracellular porphyrin accumulation and ALA-PDT cytotoxicity increased. We conclude that cisplatin treatment increases the intracellular mitROS concentration and upregulates PEPT1 and downregulates ABCG2 expression.

Photodynamic therapy (PDT) induced by protoporphyrin IX (PpIX) has been widely used in dermatological practices such as treatment of skin cancers. Clearance rate depends on different factors such as light irradiation, skin oxygenation and drug penetration. The poor penetration of 5-aminolevulinic acid (5-ALA) with topical application is limited and restrains the production of PpIX which could restrict PDT outcomes. This review will focus on techniques already used to enhance drug penetration in human skin, and will present their results, advantages, and drawbacks. Chemical and physical pretreatments will be discussed. Chemical pre-treatments comprise of drug formulation modification, use of agents that modify the heme cycle, enhance PpIX formation, and the combination of differentiation-promoting agent prior to PDT. On the other hand, physical pretreatments affect the skin barrier by creating holes in the skin or by removing stratum corneum. To promote drug penetration, iontophoresis and temperature modulation are interesting alternative methods. Cellular mechanisms enrolled during chemical or physical pretreatments have been investigated in order to understand how 5-ALA penetrates the skin, why it is preferentially metabolized in PpIX in tumour cells, and how it could be accumulated in deeper skin layers. The objective of this review is to compare clinical trials that use innovative technology to conventional PDT treatment. Most of these pretreatments present good or even better clinical outcomes than usual PDT., (Copyright © 2019 Elsevier B.V. All rights reserved.)