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Since the patients suffering from female lower genital tract diseases are getting younger and younger and the human papilloma virus (HPV) infection is becoming more widespread, the novel non-invasive precise modalities of diagnosis and therapy are required to remain structures of the organ and tissue, and fertility as well, by which the less damage to normal tissue and fewer adverse effects are able to be achieved. In all nucleated mammalian cells, 5-Aminolevulinic acid (5-ALA) is an amino acid that occurs spontaneously, which further synthesizes in the heme biosynthetic pathway into protoporphyrin IX (PpIX) as a porphyrin precursor and photosensitizing agent. Exogenous 5-ALA avoids the rate-limiting step in the process, causing PpIX buildup in tumor tissues. This tumor-selective PpIX distribution after 5-ALA application has been used successfully for tumor photodynamic diagnosis (PDD) and photodynamic therapy (PDT). Several ALA-based drugs have been used for ALA-PDD and ALA-PDT in treating many (pre)cancerous diseases, including the female lower genital tract diseases, yet the ALA-induced fluorescent theranostics is needed to be explored further. In this paper, we are going to review the studies of the mechanisms and applications mainly on ALA-mediated photodynamic reactions and its effectiveness in treating female lower genital tract diseases.

Background: Photodynamic therapy (PDT) has become one of the most effective therapies for the treatment of actinic keratosis, allowing the removal of more than one lesion in a single session. However, the pain sustained by the patient during treatment and local skin reactions can limit its use. Objectives: To determine the efficacy and safety of combined PDT (daylight PDT followed by conventional PDT) vs conventional PDT 12 weeks after treatment. Methods: The study was performed as a randomized, single‐center, non‐inferiority clinical trial with two parallel groups. A total of 51 patients with grade I and II AKs on the scalp or face were randomized. Twenty‐five patients received one session of combined PDT (combPDT), and 26 patients received one session of conventional PDT (cPDT). The primary endpoint was the reduction of AKs, 12 weeks after treatment. The secondary endpoint was the reduction in pain and local skin reaction. Results: The reduction rate of grade I and II AKs was similar in combPDT and cPDT, showing no statistically significant differences between both groups, 76.67% vs 86.63% [P =.094] and 80.48% vs 83.08% [P =.679], respectively. However, pain was significantly lower in the combPDT group (2.56 vs 5, P <.01), as were local skin reactions. Conclusions: CombPDT has proven to be as effective as cPDT for the treatment of grade I and II AKs located on the scalp and face. Furthermore, combPDT has been shown to be considerably more tolerable than cPDT, causing only mild local skin reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] 5-Aminolevulinic acid (ALA) and its derivatives, serving as the endogenous precursor of the photosensitizer (PS) protoporphyrin IX (PpIX), successfully applied in tumor imaging and photodynamic therapy (PDT). ALA and its derivatives have been used to treat actinic keratosis (AK), basal cell carcinoma (BCC), and improve the detection of superficial bladder cancer. However, the high hydrophilicity of ALA and the conversion of PpIX to heme have limited the accumulation of PpIX, hindering the efficiency and potential application of ALA-PDT. This study aims to evaluate the PDT activity of three rationally designed series of ALA-HPO prodrugs, which were based on enhancing the lipophilicity of the prodrugs and reducing the labile iron pool (LIP) through HPO iron chelators to promote PpIX accumulation. Twenty-four ALA-HPO conjugates, incorporating amide, amino acid, and ester linkages, were synthesized. Most of the conjugates, exhibited no dark-toxicity to cells, according to bioactivity evaluation. Ester conjugates 19a-g showed promoted phototoxicity when tested on tumor cell lines, and this increased phototoxicity was strongly correlated with elevated PpIX levels. Among them, conjugate 19c emerged as the most promising (HeLa, IC 50 = 24.25 ± 1.43 μM; MCF-7, IC 50 = 43.30 ± 1.76 μM; A375, IC 50 = 28.03 ± 1.00 μM), displaying superior photodynamic anticancer activity to ALA (IC 50 > 100 μM). At a concentration of 80 μM, the fluorescence intensity of PpIX induced by compound 19c in HeLa, MCF-7, and A375 cells was 18.9, 5.3, and 2.8 times higher, respectively, than that induced by ALA. In conclusion, cellular phototoxicity showed a strong correlation with intracellular PpIX fluorescence levels, indicating the potential application of ALA-HPO conjugates in ALA-PDT. [ABSTRACT FROM AUTHOR]

Since the patients suffering from female lower genital tract diseases are getting younger and younger and the human papilloma virus (HPV) infection is becoming more widespread, the novel non-invasive precise modalities of diagnosis and therapy are required to remain structures of the organ and tissue, and fertility as well, by which the less damage to normal tissue and fewer adverse effects are able to be achieved. In all nucleated mammalian cells, 5-Aminolevulinic acid (5-ALA) is an amino acid that occurs spontaneously, which further synthesizes in the heme biosynthetic pathway into protoporphyrin IX (PpIX) as a porphyrin precursor and photosensitizing agent. Exogenous 5-ALA avoids the rate-limiting step in the process, causing PpIX buildup in tumor tissues. This tumor-selective PpIX distribution after 5-ALA application has been used successfully for tumor photodynamic diagnosis (PDD) and photodynamic therapy (PDT). Several ALA-based drugs have been used for ALA-PDD and ALA-PDT in treating many (pre)cancerous diseases, including the female lower genital tract diseases, yet the ALA-induced fluorescent theranostics is needed to be explored further. In this paper, we are going to review the studies of the mechanisms and applications mainly on ALA-mediated photodynamic reactions and its effectiveness in treating female lower genital tract diseases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chen, Guo, Chen and He.)

BackgroundPhotodynamic diagnosis and narrow-band imaging could help improve the detection rate in transurethral resection (TUR) of bladder cancer. It remained controversial that the novel visualization method assisted transurethral resection (VA-TUR) could elongate patients’ survival compared to traditional TUR.MethodsWe performed electronic and manual searching until December 2020 to identify randomized controlled trials comparing VA-TUR with traditional TUR, which reported patients’ survival data. Two reviewers independently selected eligible studies, extracted data, assessed the risk of bias. Meta-analysis was conducted according to subgroups of types of visualization methods (A) and clinical stage of participants. Publication bias was detected.ResultsWe included 20 studies (reported in 28 articles) in this review. A total of 6,062 participants were randomized, and 5,217 participants were included in the analysis. Only two studies were assessed at low risk of bias. VA-TURB could significantly improve the recurrence-free survival (RFS) (HR = 0.72, 95% CI: 0.66 to 0.79, P 0.05).ConclusionVA-TUR could improve RFS and PFS in NMIBC patients. No significant difference is found among different types of VA-TUR. VA-TUR may be not indicated to MIBC patients.

Background: Photodynamic diagnosis and narrow-band imaging could help improve the detection rate in transurethral resection (TUR) of bladder cancer. It remained controversial that the novel visualization method assisted transurethral resection (VA-TUR) could elongate patients' survival compared to traditional TUR. Methods: We performed electronic and manual searching until December 2020 to identify randomized controlled trials comparing VA-TUR with traditional TUR, which reported patients' survival data. Two reviewers independently selected eligible studies, extracted data, assessed the risk of bias. Meta-analysis was conducted according to subgroups of types of visualization methods (A) and clinical stage of participants. Publication bias was detected. Results: We included 20 studies (reported in 28 articles) in this review. A total of 6,062 participants were randomized, and 5,217 participants were included in the analysis. Only two studies were assessed at low risk of bias. VA-TURB could significantly improve the recurrence-free survival (RFS) (HR = 0.72, 95% CI: 0.66 to 0.79, P <0.00001, I2 = 42%) and progression-free survival (PFS) (HR = 0.62, 95% CI: 0.46 to 0.82, P <0.0008, I2 = 0%) compared with TUR under white light. The results remain stable whatever the type of visualization method. The difference could be observed in the non-muscle-invasive bladder cancer (NMIBC) population (P <0.05) but not in the mixed population with muscle-invasive bladder cancer (MIBC) participants (P >0.05). Conclusion: VA-TUR could improve RFS and PFS in NMIBC patients. No significant difference is found among different types of VA-TUR. VA-TUR may be not indicated to MIBC patients. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is an effective treatment option for the treatment of superficial basal cell carcinoma (sBCC). Recent publications have demonstrated that PDT with 7.8% 5‐aminolaevulinic acid nanoemulsion‐based gel (BF‐200 ALA‐PDT) is an effective and safe alternative for the treatment of sBCC). To investigate the efficacy and safety of 7.8% 5‐aminolaevulinic acid nanoemulsion‐based gel (BF‐200 ALA)‐PDT for the treatment of sBCC. A non‐controlled, open‐label single centre study was conducted. Patients received one PDT cycle with two PDT sessions one‐week apart. In case that clinical‐dermoscopy evaluation of treatment outcome revealed remaining lesions, a second PDT cycle was performed. The clinical results at the dermoscopy and fluorescence diagnosis level were histologically confirmed in all patients. Treatment response was evaluated 3, 6, and 12 months after last PDT session. A total of 31 patients (12 men and 19 women), with a median age of 63.74 years were included in this study. 3‐month after PDT‐session, 23/31 patients were complete responders (74.19%) after two BF‐200 ALA ‐PDT sessions. Esthetic outcome was considered good‐to‐excellent. 5 Aminolevulinic acid 7.8% nanoemulsion‐based gel (BF‐200 ALA) PDT is an effective therapy option for the treatment of sBCC. Complete clearance rates were higher in those patients who received only one PDT cycle. These results show a similar tendency as shown in other publications. [ABSTRACT FROM AUTHOR]

ALA-mediated Photodynamic Therapy (ALA-PDT) is one of the most promising fields in Photodynamic therapy (PDT) research for cancer treatment. 5-aminolaevulinic acid (ALA) is the prodrug of the photosensitiser Protoporphyrin IX (PpIX). After ALA administration, cells generate PpIX through the haem biosynthetic pathway. Although the exact reasons for ALA/PpIX selectivity are unknown, it is believed that due to the special regulation of haem enzymes, PpIX is accumulated in the tumours. Both ALA and its derivative ALA Methyl ester, are mainly used in dermatology. Besides, ALA-PDT has been employed for palliative and even curative treatment of endoscopically accessible tumours. Lung, oesophagus, gastric and bladder carcinomas, and also oral premalignant lesions, gynaecological intraepithelial neoplasias and Barrett's oesophagus are the conditions mostly treated with ALA-PDT. However, due to the limited penetration of ALA and light, non-dermatologic uses of ALA-PDT have not moved beyond phase I clinical trials. On the other hand, ALA-induced PpIX fluorescence is successfully employed for the Photodynamic Diagnosis (PDD) or assistance in cytoreductive surgery (Fluorescence-guided Resection, FGR). ALA has been approved for the FGR of high-grade gliomas and ALA Hexyl ester, for fluorescence cystoscopy in the diagnosis of bladder cancer. ALA-FGR is currently applied in brain, bladder, lung, colon cancers, etc. and ALA-PDD for oral premalignancies, gynaecological intraepithelial lesions and peritoneal metastases, among others. Besides, PDT can be applied concomitantly in the same diagnostic procedure. This review aimed to analyse the state of the art of clinical uses of ALA in the areas of treatment and detection in the non-dermatologic oncology fields. [ABSTRACT FROM AUTHOR]

5-aminolaevulinic acid (ALA)-based photodynamic therapy (ALA-PDT) is an effective treatment for proliferative skin diseases. Many studies revealed that ALA-PDT induces apoptosis of cancer cells. However, the mechanism of PDT in warts is not fully elucidated. This study was designed to explore the efficacy of ALA-PDT for plantar warts and its possible mechanism. Twenty-five patients with plantar warts underwent four rounds of ALA-PDT at weekly intervals. Therapeutic effects were observed 1 month since last treatment. The adverse reactions were also recorded during and after the procedure. To observe histological changes, 5 patients accepted tissue biopsies before and 24 h after first PDT treatment. Twenty-two patients (88%) showed a complete response. Twenty patients complained of a mild burning sensation during treatment, and four patients developed local edema immediately after red light exposure. Five patients had burns after treatment, which disappeared within 24 h. Histologically, epidermal keratinocytes demonstrated remarkable necrocytosis and apoptosis after PDT. ALA-PDT is highly effective for treatment of plantar warts. The most common adverse effects observed in patients are pain and edema. ALA-PDT might eradicate plantar warts by activating both necrosis and apoptosis to trigger the death of proliferating keratinocytes. [ABSTRACT FROM AUTHOR]

Topical photodynamic therapy has become an established therapy option for superficial non-melanoma skin cancers with a substantial evidence base. In this update the increased choice in photosensitizers and light sources are reviewed as well as novel protocols to move beyond lesional treatment and address field therapy. Daylight PDT is emerging as an alternative to conventional office/hospital-based PDT that offers the advantage of much reduced pain. Although most studies have assessed efficacy of PDT in immune-competent patients, there is accumulating evidence for topical PDT being considered an option to assist in reducing the skin cancer burden in organ transplant recipients. The fluorescence associated with photosensitizer application can help delineate lesions prior to full treatment illumination and offers a useful adjunct to treatment in patients where diagnostic uncertainty or poor lesion outline complicates clinical care. PDT may also offer significant benefit in delaying/preventing new cancer development and combined with its recognized photo-rejuvenating effects, is emerging as an effective therapy capable of clearing certain superficial skin cancers, potentially preventing new lesions as well as facilitating photo-rejuvenating effects in treated areas.

Abstract Background Cyclosporine-A (CsA) is an immunosuppressant indicated for various immunological diseases; however, it can induce chronic kidney injury. Oxidative stress and apoptosis play a crucial role in CsA-induced nephrotoxicity. The present study evaluated the protective effect of combining 5-aminolaevulinic acid with iron (5-ALA/SFC), a precursor of heme synthesis, to enhance HO-1 activity against CsA-induced chronic nephrotoxicity. Methods Mice were divided into three groups: the control group (using olive oil as a vehicle), CsA-only group, and CsA+5-ALA/SFC group. After 28 days, the mice were sacrificed, and blood and kidney samples were collected. In addition to histological and biochemical examination, the mRNA expression of proinflammatory and profibrotic cytokines was assessed. Results Renal function in the 5-ALA/SFC treatment group as assessed by the serum creatinine and serum urea nitrogen levels was superior to that of the CsA-only treatment group, demonstrating that 5-ALA/SFC significantly attenuated CsA-induced kidney tissue inflammation, fibrosis, apoptosis, and tubular atrophy, as well as reducing the mRNA level of TNF-α, IL-6, TGF-β1, and iNOS while increasing HO-1. Conclusion The activity of 5-ALA/SFC has important implications for clarifying the mechanism of HO-1 activity in CsA-induced nephrotoxicity and may provide a favorable basis for clinical therapy. Highlights • 5-ALA/SFC improved histological and biochemical index in kidney by CsA. • 5-ALA/SFC up-regulated HO-1 and Bcl-2 expression in the injured kidney. • 5-ALA/SFC inhibited expression of inflammatory and fibrotic cytokines in the injured kidney. • 5ALA/SFC inhibited the elevation of serum 8-OHdG in CsA-induced kidney injured mice. [ABSTRACT FROM AUTHOR]

• Laser+ALA-PDT cures cervical HSIL lesions better than ALA-PDT in cervical HSIL. • Laser+ALA-PDT improves HPV regression compared with ALA-PDT. • HPV16/18 and multi-infection may be risk factors for ineffective treatment with ALA-PDT. To evaluate the effect of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) combined with CO2 laser pretreatment (Laser+ALA-PDT) on patients with cervical high-grade squamous intraepithelial lesions (HSILs). A total of 114 patients treated by ALA-PDT or Laser+ALA-PDT at 3 centers were retrospectively reviewed. The effective rate, cure rate of lesions as well as high-risk human papillomavirus (HR-HPV) regression rate and persistent infection rate in the 2 groups were compared according to 3–6 month and 9–12 months follow-ups. The characteristics and risk factors for ineffective cases were evaluated by regression analysis. At the 3–6month follow-up, the effective rate was significantly higher in the Laser+ALA-PDT group than in the ALA-PDT group (96.6% vs. 81.3%, p = 0.048). A total of 79.3% of the laser+ALA-PDT patients achieved cure rate compared with 61.3% of the ALA-PDT patients (p = 0.082). In the Laser+ALA-PDT group, the HR-HPV-negative rate was significantly higher (72.4% vs. 50.7%, p = 0.045), while the persistence rate was significantly lower (20.7% vs. 42.7%, p = 0.037). At the 9–12month follow-up, the cure rate was 83% in the ALA-PDT group, 17% lower than that in the Laser+ALA-PDT group (p = 0.055). A total of 20.8% of patients in the ALA-PDT group and 5.3% in the Laser+ALA-PDT group showed persistent HR-HPV infection (p = 0.120). Pretreatment HR-HPV type, multiple infections and treatment modality were relevant factors for PDT outcome. For patients with cervical HSIL, laser+ALA-PDT shows better efficiency and HPV regression compared with ALA-PDT. HPV16/18 and multi-infection may be risk factors for ineffective treatment with ALA-PDT. [ABSTRACT FROM AUTHOR]

• Bowen´s disease (BD) is an intraepidermal squamous cell carcinoma (SCC). • There are several alternatives for treatment of BD, including photodynamic therapy (PDT). • Photosensitizer precursors used in Europe include methyl-5-aminolaevulinate (MAL) and 5-aminolaevulinic acid (BF-200 ALA). • We designed a study with 171 patients to investigate the efficacy and safety of PDT in BD. • PDT is an effective and safe treatment option in BD. Our analysis suggests a higher rate of healing with ALA-PDT over MAL-PDT. An observational study was carried out in the photodynamic therapy (PDT) section of Fuenlabrada's hospital (Madrid, Spain). Our goal was to investigate the efficacy and safety of PDT in Bowen's disease (BD). Between June 2011-June 2017 171 patients (191 lesions) with diagnosis of BD were enrolled in the study (95 women and 76 men; average age of 74.31 years). Lesions were treated with one 5-aminolaevulinic acid (BF-200 ALA)-PDT or methyl-5-aminolaevulinate (MAL)-PDT cycle of two sessions in one week. A second treatment cycle was performed in cases of clinical persistence at 12 weeks. Our results showed that 47/55 lesions were resolved (84.75%) after one or two ALA-PDT cycle and 75/136 lesions (55.15%) after one or two MAL-PDT cycles, in the 12-month follow-up. In conclusion PDT is a safe and non-invasive treatment option in BD. In addition, our results suggest a better response with ALA-PDT over MAL-PDT. Limits: observational study with a limited number of patients. [ABSTRACT FROM AUTHOR]

Background Actinic cheilitis ( AC) is a common disease caused by chronic ultraviolet exposure. Objective Alacare is a self-adhesive, skin coloured 5-aminolaevulinic acid ( ALA) patch that has been developed for the treatment of mild to moderate actinic keratosis ( AK). Considering the good results in the treatment of AK, the standardized delivery of ALA and the simple application Alacare patch- photodynamic therapy ( PDT) appears as an interesting treatment option for AC. Methods We retrospectively assessed the efficacy, tolerability and cosmetic outcome of Alacare patch- PDT in eleven patients with AC. After occlusion with the Alacare patches for 4 hours, the AC lesions were illuminated with narrowband red light and a dose of 37 J/cm2. All patients were clinically assessed for efficacy, side effects and cosmetic outcome at 3, 6, 9 and 12 months after treatment. Results Complete clinical response at the 3-month follow-up was achieved in eight of 11 patients (72,7%) and 12 of 15 AC lesions (80,0%), respectively. Up to the final 12-month follow-up, a recurrence was observed in two lesions. The complete clinical cure rate at 1 year after Alacare patch- PDT, thus, was 66,6% (10/15 lesions). The cosmetic outcome of the treatment was excellent in all cases. Conclusion Alacare patch- PDT was found to have substantial efficacy in the treatment of mild to moderate AC. Given its ease of use, absence of long-term side effects and the excellent cosmetic results Alacare patch- PDT might be considered as a promising new treatment option for the management of AC. [ABSTRACT FROM AUTHOR]

• Superficial basal cell carcinoma (sBCC) is, after nodular, the second subtype in frequency of basal cell carcinoma. • In the last years PDT is being used as an effective alternative, especially in sBCC unsuitable for surgical treatment. • We design an observational study to investigate the efficacy and security of BF-200 ALAMAL in the treatment of sBCC. • Our results suggest a better response with BF-200 ALA-PDT over MAL-PDT in the treatment of sBCC, at 12 months of follow-up. Background: There is limited literature on efficacy in 5-aminolaevulinic acid (BF-200 ALA) and methyl-5-aminolaevulinate (MAL) for superficial basal cell carcinoma (sBCC). Aims: To investigate the efficacy and safety of PDT in sBCC. Methods: Analytical observational study between January 2014 and January 2017. Follow-up at 12, 24 and 52 weeks. Lesions were treated with one BF-200 ALA-PDT or MAL-PDT cycle of two sessions in one week. A second treatment cycle, with the same photosensitizer precursor, was performed in cases of clinical persistence at 12 weeks. Results: A total of 22 patients (30 lesions) were enrolled in the study. By sex, 13 men and 9 women. Average age of 72,14 years. In the 12-month follow-up 15/16 lesions were resolved (93,75%) after one or two BF-200 ALA-PDT cycle and 7/14 lesions (50%) after one or two MAL-PDT cycles. In most patients, tolerance to the therapy was good or regular, with no differences between the two groups. No long-term adverse effects were reported. Limitations: The observational nature and the low number of patients. Conclusion: PDT is a safe and non-invasive treatment option in sBCC. Our results suggest a better response with BF-200 ALA-PDT over MAL-PDT, at 12 months of follow-up. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is the most frequent and lethal primary brain tumor in adults. Despite multimodal therapy combining resection, radio- and alkylating chemotherapy, disease recurrence is universal and prognosis of patients is poor. Glioblastoma stem-like cells (GSC), which can be grown as neurospheres from primary tumors in vitro, appear to be resistant to the established therapies and are suspected to be the driving force for disease recurrence. Thus, efficacy of emerging therapies may depend on targeting GSC. 5-aminolaevulinic acid-mediated photodynamic therapy (5-ALA/PDT) is a promising therapeutic approach in GBM. It utilizes the selective accumulation of the photosensitizer protoporphyrin IX (PPIX) in GBM cells after application of 5-ALA. When exposed to laser light of 635 nm wavelength, PPIX initiates a photochemical reaction resulting in the generation of reactive oxygen species, which kill the tumor cells. Whether GSC accumulate PPIX and are sensitive to 5-ALA/PDT is currently unknown. Therefore, human GSC were derived from primary tumors and grown as neurospheres under serum free conditions. When subjected to exogenous 5-ALA, a dose- and time-dependent accumulation of PPIX in GSC was observed by flow cytometry, which varied between individual GSC preparations. Subsequent exposure to laser light of 635 nm wavelength substantially killed GSC, whereas treatment with 5-ALA or exposure to laser light only had no effect. LD 50 values differed between GSC preparations, but were negatively correlated with PPIX accumulation in GSC. In summary, we report for the first time that glioblastoma stem-like cells accumulate PPIX when subjected to 5-aminolaevulinic acid and are sensitive to 5-aminolaevulinc acid based photodynamic therapy. [ABSTRACT FROM AUTHOR]

Canine mammary gland tumors (CMGTs) are heterogeneous tumors and share many similar features with human breast cancer. Despite the improvement of current treatment options, new treatment modalities are required to effectively kill tumor cells without general toxicity in the treatment of CMGTs. Photodynamic therapy (PDT) is a promising method for cancer treatment. However, there is a limited study evaluating the therapeutic efficacy of PDT in the treatment of CMGTs. In this context, we, for the first time, investigated the therapeutic potential of 5-aminolaevulinic acid (5-ALA) mediated PDT at 6 and 12 J/cm2 in two different subtypes [Tubulopapillary carcinoma (TPC) and carcinosarcoma (CS)] cells via different molecular analysis. The cytotoxic effects of 5-ALA/PDT on these cells were analyzed by intracellular PpIX level, WST-1 and ROS analysis. Furthermore, the underlying moleculer mechanism of 5-ALA/PDT mediated apoptotic effects on TPC and CS cells were evaluated Annexin V, AO/PI, RT-PCR and western blot analysis. The 5-ALA/PDT treatment upon irradiation considerably inhibited the viability of both TPC and CS cells (p <0.01) and caused apoptotic death through elevated ROS levels, the activation of Caspase-9, and Caspase-3, and the overexpression of Bax. However, the response of TPC and CS cells to 5-ALA/PDT was different. Our preliminary in vitro findings provide novel insights into the molecular mechanisms underlying 5-ALA/PDT mediated apoptosis in both TPC and CS cells. However, the therapeutic response of CMGT cells to 5-ALA/PDT is limited. • 5-ALA/PDT significantly reduces the viability of TPC and CS cells. • 5-ALA/PDT causes apoptosis in CMGT cells via the activation of pro-apoptotic genes and increased intracellular ROS levels. • PpIX concentration and light fluence affect 5-ALA/PDT response of TPC and CS cells. [ABSTRACT FROM AUTHOR]

5-Aminolaevulinic acid (ALA) prodrugs have been widely used in photodynamic therapy (PDT) as precursors to the natural photosensitizer, protoporphyrin IX (PpIX). The main disadvantage of this therapy is that ALA is poorly absorbed by cells due to its high hydrophilicity. In order to improve the therapeutical effect and induce higher yields of PpIX, a range of prodrugs of ALA conjugated to 3-hydroxypyridin-4-ones (HPO) were synthesized. Pharmacokinetic studies indicated that some of the ALA–HPO conjugates are more efficient than ALA for PpIX production in the human breast adenocarcinoma cell line (MDA-MB-468). The intracellular porphyrin fluorescence levels showed good correlation with cellular phototoxicity following light exposure, suggesting the potential application of the ALA–HPO conjugates in photodynamic therapy. [ABSTRACT FROM AUTHOR]

[english] Actinic keratosis is one of the most commonly treated skin conditions. A number of studies have recently been published on the treatment of this ailment using photodynamic therapy. The authors of this letter are concerned about the interpretation of some of these studies and would like to outline possible misinterpretations which may arise due to an incomplete analysis of the study reports available. Clearly, the “ideal” therapy for actinic keratosis should be a carefully chosen compromise between undesired side-effects and therapeutic efficacy and needs to be based on a consideration of all of the relevant clinical studies.[german] Aktinische Keratosen gehören zu den meistbehandelten Hautschäden. Eine Reihe der in den letzten Jahren veröffentlichten Studien beschäftigte sich mit ihrer Behandlung durch photodynamische Therapie. Die Bewertungen einiger dieser Studien veranlassten die Autoren dieses Briefes, mögliche Missinterpretationen der Daten herauszustellen, die infolge unvollständiger Analyse der einbezogenen Studienberichte und unvollständiger Berücksichtigung ihrer Randbedingungen auftreten können. Unbestritten ist dabei, dass die „ideale“ Therapie der aktinischen Keratose ein sorgfältig abgewogener Kompromiss zwischen therapeutischer Wirkung und unerwünschter Nebenwirkung sein muss, der auf der Berücksichtigung aller relevanten klinischen Studien und ihrer Randbedingungen basiert.

The European Commission has recently issued a marketing authorisation valid throughout the European Union for 5-aminolaevulinic acid (Ameluz). The decision was based on the favorable opinion of the CHMP recommending a marketing authorization for 5-aminolaevulinic acid for treatment of actinic keratosis of mild to moderate intensity on the face and scalp. The active substance is a sensitizer used in photodynamic/radiation therapy (ATC code L01XD04). The gel should cover the lesions and approximately 5 mm of the surrounding area with a film of about 1 mm thickness. The entire treatment area should be illuminated with a red light source, either with a narrow spectrum around 630 nm and a light dose of approximately 37 J/cm2 or a broader and continuous spectrum in the range between 570 and 670 nm with a light dose between 75 and 200 J/cm2. One session of photodynamic therapy should be administered for single or multiple lesions. Non- or partially responding lesions should be retreated in a second session 3 months after the first treatment. 5-aminolaevulinic acid is metabolized to protoporphyrin IX, a photoactive compound which accumulates intracellularly in the treated actinic keratosis lesions. Protoporphyrin IX is activated by illumination with red light of a suitable wavelength and energy. In the presence of oxygen, reactive oxygen species are formed which causes damage of cellular components and eventually destroys the target cells. The benefit with 5-aminolaevulinic acid is its ability to improve the complete response rate of actinic keratosis lesions. The most common side effects are reactions at the site of application. The objective of this article is to summarize the scientific review of the application. The detailed scientific assessment report and product information, including the summary of product characteristics (SmPC), are available on the EMA website (). [ABSTRACT FROM AUTHOR]

Competing Interests: Competing interests: None.

Introduction: Aquaporin channels (AQPs) are a group of integral membrane proteins that regulate the transport of water through cell membranes. Previous studies have shown that up-regulation of AQP1 and AQP4, two of the predominant AQPs in the human brain, in high grade glial tumors contribute to cerebral edema. Others link AQPs to the regulation of human glioma cell migration and invasion. The aim of this study was to determine AQPs expression in tumor tissue harboring 5-aminolevulinic acid (ALA)-induced porphyrin fluorescence with flow cytometry and compare it to the expression in normal brain tissue. Methods: Tissue samples were obtained from fluorescing brain tumors of 26 patients treated with ALA prior to surgery (20 mg/kg b.w.). Expression levels of aquaporin channels were measured in primary tissue cultures using a FACS CANTO I flow cytometer. A control group consisted of four non-fluorescing tissue samples, the C6 and the U87 cell line. Results: Nineteen gliomas (14 high grade, 5 low grade) and 7 metastases were analyzed. On the 4th postoperative day, expression levels of AQP4 channels, but not of AQP1 channels, were significantly increased in samples from fluorescing tissue compared to non-fluorescing tissue. In addition we could see how ALA induces fluorescence in metastases. Conclusion: Flow cytometry appears to be an auspicious method for the analysis of porphyrins and AQPs in primary brain cell tumor cultures. ALA fluorescing tissue showed higher AQP4 expression compared to normal brain tissue. The demonstrated expression in a context with ALA could open a targeted therapeutic spectrum, for example to selectively target AQP4. [ABSTRACT FROM AUTHOR]

Objective This meta-analysis was designed to assess the efficacy of topical 5-aminolaevulinic acid ( ALA) photodynamic therapy ( PDT) in Chinese patients with condylomata acuminata ( CA). Methods Electronic literature databases ( Medline, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang database) were searched for relevant randomized controlled trials ( RCTs) published prior to October 2012. Only RCTs that compared ALA-PDT to non- ALA- PDT for patients with genital condylomata were selected. The outcomes included the recurrence rate and adverse events. The risk ratios ( RRs) and 95% confidence intervals ( CIs) were calculated as the ALA-PDT vs. without ALA-PDT. Results Twenty RCTs composed of 1903 patients ( ALA-PDT, n = 1106; non- ALA- PDT, n = 797) were included in the meta-analysis. ALA-PDT decreased the recurrence rate within 12 week after treatment (vs. without ALA-PDT, RR: 0.28, 95% CI: 0.22-0.35) and 24 week after treatment (vs. without ALA-PDT, RR: 0.24, 95% CI: 0.17-0.34) in a fixed-effect model. The common adverse events related ALA-PDT included a mild burning and/or stinging sensation, erythema, mild edema, erosion, and hyperpigmentation. Conclusion Local application of ALA-PDT reduced recurrence rate vs. without ALA-PDT. The use of ALA- PDT should be considered as a feasible therapy for the treatment of CA. [ABSTRACT FROM AUTHOR]

ABSTRACT Serum/plasma concentrations of 5-aminolaevulinic acid (ALA) and porphobilinogen (PBG) are elevated in patients with acute hepatic porphyrias, especially during acute attacks. Current assays require lengthy sample pre-treatment and derivatization steps. We report here a rapid, sensitive and specific hydrophilic interaction liquid chromatography-tandem mass spectrometry method for the direct and simultaneous quantitation of ALA and PBG in serum or plasma following simple protein precipitation with acetonitrile and centrifugation prior to injection. ALA and PBG were detected using selected reaction monitoring mode, following positive atmospheric pressure chemical ionization. Calibration was linear from 0.05 to 50 µmol/L for ALA and PBG. For both analytes, imprecision (relative standard deviation) was <13% and accuracy (percentage nominal concentrations) was between 92 and 107%. The method was successfully applied to the measurement of ALA and PBG in serum or plasma samples for the screening, biochemical diagnosis and treatment monitoring of patients with acute hepatic porphyrias. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Urinary concentrations of 5-aminolaevulinic acid (ALA) and porphobilinogen (PBG) are elevated in patients with acute hepatic porphyrias, especially during acute attacks. Current assays require lengthy sample pre-treatment and derivatisation steps. We report here a rapid, sensitive and specific hydrophilic interaction liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, for the direct and simultaneous quantitation of ALA and PBG in urine following simple dilution with acetonitrile and centrifugation prior to injection. ALA and PBG were detected using selected reaction monitoring mode, following positive electrospray ionisation. Urine samples ( N = 46) from active and latent mutation-confirmed acute hepatic porphyria patients and normal subjects ( N = 45) were analysed and the results compared with those of a commercially available spectrophotometric method. The validated calibration range was 3-3000 µmol/L for ALA and 2-2000 µmol/L for PBG. For both analytes, imprecision (relative standard deviation) was less than 5% and accuracy (percentage nominal concentrations) was between 88 and 109%. The lower limit of quantitation was 0.1 μmol/L for both analytes. The calculated LC-MS/MS and spectrophotometric results from patient samples compared well [Pearson correlation ( r2) of 0.99 and 0.95, for ALA and PBG, respectively]. The method was successfully applied to the measurement of ALA and PBG in urine samples for the screening, biochemical diagnosis and treatment monitoring of patients with acute hepatic porphyrias. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT This article discusses the separation, analysis and characterisation of intermediates and oxidative by-products of the haem biosynthetic pathway by liquid chromatography and mass spectrometry. Techniques reviewed include high-performance liquid chromatography, ultra-high-performance liquid chromatography, capillary electrophoresis, ion mobility spectrometry, mass spectrometry and tandem mass spectrometry. The emphasis was on the analysis of biological and clinical samples. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To assess the diagnostic accuracy of photodynamic diagnostic (PDD) ureterorenoscopy for detecting upper-urinary tract transitional cell carcinoma (UUT-TCC) in our initial 3years, and compare the results with that of white light ureterorenoscopy (WLU). Patients and methods: Between August 2007 and March 2010, 32 patients underwent PDD flexible ureterorenoscopy for UUT-TCC. Oral 5-aminolaevulinic acid (5-ALA) was used as the photosensitiser. The sensitivity, specificity and detection rate of PDD were calculated. Results: The sensitivity, specificity, positive and negative predictive values of PDD for detecting abnormal tissue were 96%, 100%, 100% and 88%, compared to the results of WLU of 80%, 86%, 95% and 55%, respectively. PDD was able to detect 96% (24/25) of the abnormal tissue and 96% (21/22) of cancerous tissue, while WLU detected 80% (20/25) of abnormal tissue and 91% (20/22) of the tumour tissue. Three patients of the 32 (10%) developed side-effects related to 5-ALA; two patients developed a facial-skin photosensitive reaction and one developed hypotension. All were treated conservatively, with no long-term effects. Conclusion: PDD can be used safely in the UUT, and with a higher sensitivity, specificity and detection rate than standard WLU for detecting UUT tumours. [Copyright &y& Elsevier]

Summary: Background: Although discovered over a century ago it is only in the last 25 years that photodynamic therapy (PDT) has been the focus of intense research. This versatile treatment modality has been shown to be effective in treating a wide variety of malignancies, and with the increasing incidence of non-melanoma skin cancer (NMSC) is a recognised treatment in dermatology clinics worldwide. There is little known as to whether different body sites influence the uptake and conversion of 5-aminolaevulinic acid (ALA) or methyl aminolaevulinate (MAL) to protoporphyrin IX (PpIX). In this study we investigated the characteristics of PpIX fluorescence within normal skin following the application of both ALA and MAL to four different body sites and the effect of tape stripping. Methods: A total of 17 healthy volunteers were recruited, and both ALA and MAL were applied to the inner forearm, outer forearm, lower leg and back for 4h. PpIX fluorescence was detected using a non-invasive spectroscopy system. Results and conclusions: PpIX fluorescence (following the application of either ALA or MAL) does vary significantly at different body sites with the lower leg producing the least. Following the application of ALA, peak fluorescence was noted at all body sites at 24h, except the lower leg, which peaked at 7h. In contrast MAL induced fluorescence at all body sites, peaked earlier at 7h and had significantly decreased by 24h. Removal of the stratum corneum by tape stripping was also shown to significantly increase PpIX fluorescence but did not alter the time course. [Copyright &y& Elsevier]

Summary: Background: Topical photodynamic therapy (PDT) using 5-aminolaevulinic acid (ALA) and its methylated ester, methyl aminolevulinate (MAL) is widely used to treat superficial non-melanoma skin cancer (NMSC). It has been proposed that ALA PDT is more painful than MAL PDT. The aim of this paper was to compare pain scores of MAL PDT with ALA PDT in our patients and to analyse the relationship between various parameters and pain during PDT. Methods: We retrospectively reviewed case notes and electronic records for all patients with superficial NMSC treated with PDT from June 2007 to March 2009. Results: On univariate analysis of patients with single lesions only, we observed no association between pain and lesion diameter or pro-drug or dose or diagnosis. Pre-treatment PpIX fluorescence was significantly associated with pain. However on univariate analysis of all patients (whether single or multiple lesions) treated with PDT, MAL was associated with significantly less pain than ALA. When all the recorded variables were taken into account (multivariate analysis), diagnosis, pre-treatment PpIX fluorescence and lesion diameter were associated with pain. Conclusions: Our data lends some support to previous published reports suggesting that the MAL PDT regime is less painful than that for ALA PDT. However, PDT pain is multifactorial and choice of photosensitiser is probably not a major pain determining factor. A prospective randomised study, with the same incubation periods for each pro-drug, is needed to definitively answer the question as to whether or not MAL PDT causes less pain than ALA PDT. [Copyright &y& Elsevier]

Abstract: In photodynamic therapy (PDT) a combination of visible light and a sensitising drug causes the destruction of selected cells. Aminolaevulinic acid (ALA) has been widely used in topical PDT for over 15years. However, ALA does not possess favourable physicochemical properties for skin penetration. Consequently, the clearance rates for difficult to treat lesions, such as nodular basal cell carcinomas are relatively low. For the first time, equimolar concentrations of ALA, methyl-ALA (m-ALA) and hexyl-ALA (h-ALA) have been incorporated into a bioadhesive patch-based system. In vitro penetration studies into excised porcine skin revealed that ALA patches containing relatively high loadings (226.7μmolcm−2) were associated with significantly greater tissue concentrations (70.7μmolcm−3) than patches containing m-ALA (16.3μmolcm−3) or h-ALA (17.4μmolcm−3). ALA was also found to be the most efficient inducer of protoporphyrin (PpIX) fluorescence in mice, in vivo (maximum mean fluorescence: ALA=236.2a.u., m-ALA=175.1a.u., h-ALA=193.5a.u.). However, when the lipophilic hexylester was formulated in a pressure sensitive adhesive (PSA) patch, significantly higher PpIX levels were achieved compared to all bioadhesive systems tested. Of major importance, PSA patches containing relatively low h-ALA loadings induced high PpIX levels, which were localised to the application area. This study has highlighted the importance of rational selection of both the active agent and the delivery system. Bioadhesive preparations containing ALA are ideal for delivery to moist environments; whereas h-ALA-loaded PSA systems may facilitate enhanced delivery to dry areas of skin. In addition, owing to the relatively low loadings of h-ALA required in PSA patches, the costs of clinical PDT may potentially be reduced. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Penetration enhancement of two topical 5-aminolaevulinic acid formulations for photodynamic therapy by erbium:YAG laser ablation of the stratum corneum: continuous versus fractional ablation. Experimental Dermatology 2010; 19: 806–812. 5-Aminolaevulinic acid (ALA) is used in photodynamic therapy (PDT). Response rates of PDT vary widely, which may be because of the limited uptake of topically applied photosensitisers. We investigated skin penetration and fluorescence induction of protoporphyrin IX (PpIX) after applying either 20% ALA cream or 20% aminolaevulinic acid solution on laser-stripped stratum corneum (SC) in an ex vivo full-thickness porcine skin model. Both formulations are used in clinical practice. To enhance the skin penetration of ALA, we used two different 2940-nm erbium:yttrium–aluminium–garnet (Er:YAG) laser systems to partially ablate the SC: continuous and fractional ablation. Different fluences were applied ranging from 0.5 to 1.5 J/cm2 (continuous ablation) and from 4 to 24 J/cm2 (fractional ablation). Fluorescence microscopy was used for detecting PpIX-induced fluorescence. Compared to skin without laser pretreatment, mean fluorescence intensity (MFI) of PpIX was enhanced 13.8-fold after continuous ablation with 1.0 J/cm2 and 7.3-fold after fractional ablation with 4 J/cm2; each laser procedure was followed by 4-h incubation with lipophilic ALA cream. Optimal parameters for continuous ablation without damage to the epidermis were 1 J/cm2 for both formulations, fractional ablation was best with 4 J/cm2. Histological evaluations of laser-treated skin showed necrosis and apoptosis, depending on light dose. In laser-stripped skin, PpIX fluorescence was detected earlier and reached deeper epidermal layers than in untreated skin. Continuous laser ablation induced higher PpIX fluorescence levels than fractional ablation. This method offers a promising new tool for enhancing ALA penetration in PDT without damaging the underlying tissue. [ABSTRACT FROM AUTHOR]

Abstract: Background: Ultrasound therapy is a new modality in the control of malignant cancers. The aim of the present study was to investigate the effect of 5-aminolaevulinic acid on the ultrasonic killing action in the cancer cells. Materials/methods: The K562 cells as a cancer cell model were subjected to investigate the effect of 5-aminolaevulinic acid (5-ALA) on the ultrasonic killing action, in which the 5-ALA concentration was 2mM and the ultrasound exposure was 15 s at the intensity of 0.46W/cm2 and the frequency of 1.7MHz. Cytotoxicity was investigated 24h after ultrasound exposure using the trypan blue exclusion test. Ultrastructural cell morphology and mitochondrial changes were observed using transmission electron microscopy (TEM). Mitochondrial membrane potential (ΔΨm) was evaluated using Rhodamine 123 assay. Results: The death rates of the K562 cells in the controls including sham radiation and 5-ALA treatment alone were 1.81±0.13%, 1.27±0.20%, respectively. Those in ultrasound radiation alone and 5-ALA-ultrasound treatment were 12.61±2.63%, 46.87±4.09%, respectively. There were significant differences between 5-ALA-ultrasound treatment, ultrasound radiation alone and the controls (P <0.05). TEM showed that the mitochondria expanding and some vacuoles were found in the ultrasound-treated cells. After the treatment of ultrasound and 5-ALA together some cells presented typical characteristics of apoptotic cells, such as nuclear condensation and crescent formation. Mitochondria of the cells were damaged more seriously than those treated by ultrasound alone, there were obvious swollen mitochondria and mitochondria in which cristae were almost perfectly disappeared, and more vacuolar mitochondria were founded. Mitochondrial membrane potential (ΔΨm) was more significantly collapsed when the K562 cells were exposed to 2mM 5-ALA for 4h and then 0.46W/cm2 irradiation of ultrasound than ultrasound radiation alone. Conclusion: 5-ALA pretreatment significantly enhanced the cytotoxicity of ultrasound radiation in K562 cells. The damage of mitochondria structure and function might be an important cause of cell death in K562 cells induced by the treatment of ultrasound radiation and 5-ALA together. [Copyright &y& Elsevier]

Aminolaevulinic acid (ALA) is known to poorly penetrate into thick lesions, such as nodular basal cell carcinomas. Short chain ALA esters, possessing increased lipophilicity relative to their hydrophilic parent, have previously been shown to be highly efficient at inducing protoporphyrin IX (PpIX) production in cell culture, at equimolar concentrations. In contrast, in vitro skin permeation and in vivo animal studies, which up to now have compared prodrugs on a % w/w basis, have failed to demonstrate such benefits. For the first time, equimolar concentrations of ALA, methyl-ALA (m-ALA) and hexyl-ALA (h-ALA) have been incorporated into an o/w cream preparation. In vitro penetration studies into excised porcine skin revealed that increased levels of h-ALA, compared to ALA and m-ALA were found in the upper skin layers, at all drug loadings studied. Topical application of the formulations to nude murine skin in vivo, revealed that creams containing h-ALA induced significantly higher levels of peak PpIX fluorescence (Fmax = 289.0) at low concentrations compared to m-ALA (Fmax = 159.2) and ALA (Fmax = 191.9). Importantly, this study indicates that when compared on an equimolar basis, h-ALA has improved skin penetration, leading to enhanced PpIX production compared to the parent drug and m-ALA. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:3486–3498, 2010 [ABSTRACT FROM AUTHOR]

Background/purpose: Based on the observation that increasing skin temperature could improve 5-aminolevulinic acid (ALA) penetration and accumulation of protoporphyrin IX (PpIX) in the ALA-based photodynamic therapy (PDT), this study was designed to investigate how temperature change varied the therapeutic effect of ALA-based PDT in vitro. Methods: HaCat cells were cultured with or without ALA at various temperatures. ALA uptake and PpIX accumulation were analyzed before laser irradiation as the baseline. After irradiation, cell death and cytokine secretions in the media, including interleukin (IL)-1α, tumor necrosis factor (TNF)-α and basic fibroblast growth factor (bFGF) were assayed, and the morphological changes were recorded. Results: With increasing temperature, the amount of ALA uptake, intracellular PpIX concentration and cell death increased in both the PDT and the non-PDT groups. Secretions of IL-1α, TNF-α and bFGF also increased and reached a peak around 44–47 °C and then declined at a higher temperature. This biphasic response might be due to protein thermolysis that occurs when cells reach beyond thermal tolerance. Conclusions: Elevating temperature could augment photodynamic reactions to a certain extent, but adverse effects occurred when cells were overheated. [ABSTRACT FROM AUTHOR]

Summary: Photodynamic therapy (PDT) is based on the association of a light source and light sensitive agents in order to cause the selective death of tumor cells. To evaluate topical 5-aminolaevulinic acid (5-ALA) and diode laser photodynamic single session therapy single session for non-melanoma skin cancer (NMSC), a long-term follow-up was performed. Nineteen Bowen''s disease (BD) and 15 basal cell carcinoma (BCC) lesions were submitted to 6-h topical and occlusive 20% 5-ALA plus DMSO and EDTA, and later were exposed to 630nm diode laser, 100 or 300Jcm−2 dose. At 3 months tumor-free rate was 91.2% (31/34) whereas at 60 months, 57.7% (15/26), slightly higher in BCC (63.6%; 7/11). The relation between the reduction of the clinical response and the increase of tumor dimension observed at 18 months was lost at 60 months. The sBCC recurrence was earlier compared to the nBCC one. ALA-PDT offered important advantages: it is minimally invasive, an option for patients under risk of surgical complications; clinical feasibility; treatment of multiple lesions in only one session or lesions in poor healing sites and superior esthetical results. However, the recurrence rate increase after ALA-PDT diode laser single session can be observed at long-term follow-up, and the repetitive sessions, an additional advantage of the method, is strongly recommended. The clinical response and recurrence time seem to be related to the laser light dose and NMSC types/sub-types, thickness and dimension, which must be considered for the choice of the ALA-PDT. [Copyright &y& Elsevier]

Background: Allergic contact dermatitis to methyl aminolaevulinate (Metvix™) after topical application in photodynamic therapy (PDT) has previously been described in case reports. Objective: To compare the frequency of sensitization to Metvix® cream in a group of patients previously treated at least five times with Metvix-PDT with the frequency observed in an unexposed control group. Methods: Twenty patients treated five times or more with Metvix-PDT and 60 controls with no prior exposure to Metvix® were patch tested with Metvix® cream and Metvix® placebo cream. Subsequently, the patients were interviewed to determine the relevance of a positive patch test reaction to Metvix®. Results: Of 20 patients treated with Metvix-PDT, 7 were sensitized to Metvix® cream, giving a sensation risk of 35%. In the control group, 1 of 60 became sensitized after a single exposure to Metvix® cream (1.7%). There was no reaction to the placebo cream. The positive patch tests to Metvix® were considered relevant in four of seven patients (57%). Conclusions: This study demonstrates a considerable risk of sensitization after Metvix-PDT. We suggest that the patients are interviewed to detect late or persistent local reactions after PDT. These reactions are often considered to be local infections but may represent allergic contact dermatitis, and therefore, patients should be offered patch testing with Metvix® cream. [ABSTRACT FROM AUTHOR]

Abstract: The structurally related tetrapyrrolic pigments are a group of natural products that participate in many of the fundamental biosynthetic and catabolic processes of living organisms. Porphobilinogen synthase catalyzes a rate-limiting step for the biosyntheses of tetrapyrrolic natural products. In the present study, a variety of new substrate analogs and reaction intermediate analogs were synthesized, which were used as probes for studying the active site of rat porphobilinogen synthase. The compounds 1, 3, 6, 9, 14, 16, and 28 were found to be competitive inhibitors of rat porphobilinogen synthase with inhibition constants ranging from 0.96 to 73.04mM. Compounds 7, 10, 12, 13, 15, 17, 18, and 26 were found to be irreversible enzyme inhibitors. For irreversible inhibitors, loose-binding inhibitors were found to give stronger inactivation. The amino group and carboxyl group of the analogs were found to be important for their binding to the enzyme. This study increased our understanding of the active site of porphobilinogen synthase. [Copyright &y& Elsevier]

• 5-aminolevulinic acid photodynamic therapy is a non-invasive and highly effective therapeutic method for remission of cervical HSIL/CIN2 in women with fertility requirements. • 5-aminolevulinic acid photodynamic therapy can a highly effective therapeutic procedure for removing high risk HPV infection rapidly and maintain the effect for a long time. • HPV16/18-infected women need more sessions of 5-aminolevulinic acid photodynamic therapy to eradicate cervical lesion and HPV infection. To evaluate the histologic response rate of high-grade squamous intraepithelial lesion (HSIL)/cervical intraepithelial neoplasia 2 (CIN2) of the cervix after photodynamic therapy (PDT) treatment in women with fertility requirements. A retrospective study was carried out comprising 31 female patients aged 20–38 years with histologically confirmed HSIL/CIN2 with high-risk human papillomavirus (hrHPV) infection. Patients were treated with three sessions of 20% 5-aminolevulinic acid (5-ALA) PDT at intervals of 7–14 days. All patients had a follow-up including cytology, HPV testing and colposcopy-directed biopsy after PDT treatment at the 6-month and 12-month follow-up points. The main outcome measure was efficacy, defined as complete histologic remission 12 months after PDT. Secondary outcomes were the remission of HPV infection and the adverse effects of PDT treatment. At the 12-month follow-up, 21 out of 27 patients (77.78%) and 4 out of 27 patients (14.81%) showed histologic disappearance and histologic regression, respectively. Only 7.41% (2/27) patients persisted with HSIL/CIN2. In addition, no patients progressed to CIN3 or carcinoma. The total baseline HPV remission rate was 62.96% (17/27). The remission rate of HPV16/18 was statistically significant compared to the other hrHPV (57.14% vs. 100%, p = 0.016) in the group with HISL/CIN2 disappearance. Adverse events were mild, with increased vaginal secretion and abdominal pain being the most common complaints. There was no report of adverse events such as vaginal bleeding, colporrhagia, ulcer, or abdominal pain after PDT treatment. 5-ALA-PDT shows a favorable efficacy and safety profile and represents a promising alternative to observation and surgical procedures in patients with HSIL/CIN2 who have fertility requirements. [ABSTRACT FROM AUTHOR]

Multicentre randomized controlled studies now demonstrate high efficacy of topical photodynamic therapy (PDT) for actinic keratoses, Bowen’s disease (BD) and superficial basal cell carcinoma (BCC), and efficacy in thin nodular BCC, while confirming the superiority of cosmetic outcome over standard therapies. Long-term follow-up studies are also now available, indicating that PDT has recurrence rates equivalent to other standard therapies in BD and superficial BCC, but with lower sustained efficacy than surgery in nodular BCC. In contrast, current evidence does not support the use of topical PDT for squamous cell carcinoma. PDT can reduce the number of new lesions developing in patients at high risk of skin cancer and may have a role as a preventive therapy. Case reports and small series attest to the potential of PDT in a wide range of inflammatory/infective dermatoses, although recent studies indicate insufficient evidence to support its use in psoriasis. There is an accumulating evidence base for the use of PDT in acne, while detailed study of an optimized protocol is still required. In addition to high-quality treatment site cosmesis, several studies observe improvements in aspects of photoageing. Management of treatment-related pain/discomfort is a challenge in a minority of patients, and the modality is otherwise well tolerated. Long-term studies provide reassurance over the safety of repeated use of PDT. [ABSTRACT FROM AUTHOR]

Abstract: The development of a reliable sensitive method for the HPLC determination of 5-aminolaevulinic acid (ALA) and ALA esters in cell lysates is described. The method relies on the quantification of a fluorescent derivative of ALA following its derivatisation with acetylacetone and formaldehyde. Following this procedure it is possible to quantify ALA in cell lysates with no need for pre-purification of the sample. The method has been validated in two ranges of concentration (0.6–65μM, 0.1–10μg/mL, and 30–600μM, 5–100μg/mL), and has also been extended and validated for the determination of ALA released from ALA prodrugs after acidic hydrolysis. [Copyright &y& Elsevier]

Background: Squamous cell carcinomas (SCCs) are common skin tumors in cats. We investigated photodynamic therapy (PDT) using the photosensitizing agent 5-aminolaevulinic acid (5-ALA) topically and a high-intensity red light source. Hypothesis: PDT is a safe and effective treatment for feline SCCs. Animals: Fifty-five client-owned cats with superficial nasal planum SCCs. Methods: Prospective, uncontrolled clinical trial. PDT was performed using topical 5-ALA and light of peak wavelength 635 nm. Adverse effects, response, and tumor control were evaluated. Results: 53/55 (96%) cats responded to therapy, and there was a complete response in 47/55 (85%). Six cats (11%) had a partial response. Of the 47 cats with complete response to a single treatment, 24 recurred (51%), with a median time to recurrence of 157 days (95% confidence interval, 109–205 days). Repeat PDT was performed in 22 cats, and at a median follow-up of 1,146 days, 23 (45%) cats were alive and disease free, 17 (33%) had to be euthanized due to tumor recurrence, and 11 (22%) were euthanized for other reasons. Only transient mild local adverse effects were observed after treatment. Conclusions and Clinical Importance: PDT using 5-ALA and a red light source was safe, well tolerated, and effective in the treatment of superficial nasal planum SCCs of cats and offers an alternative to conventional therapy. Although initial response rates were high, this treatment did not lead to a durable remission or cure in all cases. [ABSTRACT FROM AUTHOR]

Background: Photodynamic therapy (PDT) involves the use of a photosensitizing agent, which may require metabolic synthesis (i.e. a prodrug), followed by light activation. Numerous studies have advanced PDT as a means for treating bacteria, fungi and viruses. In this study, the photoinactivation of Herpes simplex virus type 1 (HSV-1) in human keratinocytes using 5-aminolaevulinic acid (5-ALA) was investigated. Methods: HaCat cells were infected with HSV-1 and treated with 5-ALA to verify its antiviral effect during the stages of adsorption and penetration to host cells. Immunoblot analysis was used to estimate the effect of ALA–PDT on the production of viral proteins glycoprotein D (gD), infected cell proteins (ICP) 27 and virion protein (VP) 16. We also investigated whether the effect of ALA–PDT was associated with a cellular apoptotic mechanism through DNA fragmentation and the study of p53, PARP and caspase-3 protein expression. Results: While the treatment of ALA–PDT after the viral adsorption period reduced HSV-1 replication by about 70%, it did not act on the virus in the first phase of infection. The viral proteins' expressions were reduced by ALA–PDT treatments. There was no evidence of ALA–PDT-induced apoptosis. Conclusion: Our data suggest that the target of photoinactivation appears to be viral replication and not a cellular response. [ABSTRACT FROM AUTHOR]

Background 5-Aminolaevulinic acid (ALA) and its esters act as precursors to the fluorescent photosensitizer protoporphyrin IX (PpIX) in photodynamic therapy (PDT). There is little information about how ALA and its esters induce PpIX synthesis and photodynamic effects in cell lines derived from the skin. Objectives We compared the amount of PpIX synthesis induced by ALA and its esters in skin cell lines, and evaluated the relationship of PpIX synthesis to photodynamic effects by ALA and its esters in vitro. Methods Four cell lines, including human epidermal keratinocytes (HEK), human dermal fibroblast (hF), A431, and TXM13 were used. Cell survival was evaluated by the MTT assay. Fluorescence spectroscopy was used to measure the amount of PpIX synthesis induced by ALA and its esters. Flow cytometry measured cell death induced by ALA- and its esters-mediated PDT. Results ALA and its esters were not toxic at concentrations lower than 2 mmol L−1 in all cell lines. PpIX synthesis was dose-dependent at low doses (0·01–0·1 mmol L−1), and ALA esters were more effective than ALA. Cell death occurred from necrosis rather than apoptosis just after light irradiation illumination on both ALA and its esters-treated cells. Cell death related more to PpIX synthesis than the irradiation light dose. Conclusions PpIX production by ALA and its esters was induced on both normal and malignant cell lines derived from the skin, and cell death of PDT responses is closely related to the amount of PpIX synthesis rather than to the irradiation dose. [ABSTRACT FROM AUTHOR]

Abstract: The relation between haem biosynthesis and intestinal iron absorption is not well understood, we therefore investigated the effect of compounds that alter haem metabolism on duodenal iron absorption. CD1 mice were treated with either an inhibitor (succinyl acetone (SA)) or stimulator (2-allyl-2-isopropylacetamide (AIA)) of haem biosynthesis. 5-Aminolaevulinic acid (ALA) dehydratase and urinary ALA and porphobilinogen (PBG) levels, were determined. Intestinal iron absorption was assayed with in vivo and in vitro techniques. Liver hepcidin (Hamp1) and duodenal iron transporter mRNA levels were measured using RT-PCR. AIA caused increased hepatic ALA synthase (1.6-fold) and ALA dehydratase (1.4-fold, both p <0.005) activities and increased urinary ALA and PBG excretion (2.1- and 1.4-fold, p <0.005, p <0.05, respectively). In vivo intestinal iron absorption was reduced to 49% of control (p <0.005). Mice treated with SA showed decreased urinary ALA and PBG levels (75 and 55% control, both p <0.005) and reductions in both ALA synthase and ALA dehydratase activities (77 and 56% control, p <0.05, p <0.005, respectively) in the liver. Liver and duodenal haem and cytochrome oxidase levels were not significantly decreased. Iron absorption was enhanced (1.26-fold, p <0.05) and hepatic Hamp1 mRNA was reduced (53% of control, p <0.05). In vitro duodenal iron uptake after mice were injected with SA also demonstrated an increase in Fe(III) reduction and uptake (1.27- and 1.41-fold, p <0.01 respectively). Simultaneous injections of SA and ALA blocked the enhancing effect on iron absorption seen with SA alone. We conclude that alterations in haem biosynthesis can influence iron absorption and in particular, the intermediate ALA seems to be an inhibitor of iron absorption. [Copyright &y& Elsevier]

Background/purpose: 5-aminolaevulinic acid-based photodynamic therapy (ALA-PDT) is widely performed in the clinical setting for superficial skin cancers, giving favorable results, but residual tumor and recurrence occur occasionally. Thioredoxin is a common antioxidant that suppresses apoptosis and facilitates cell growth. We investigated the expression of thioredoxin following ALA-PDT in human skin squamous cell carcinoma cell line, HSC-5. Methods: ALA-PDT was performed in HSC-5 cells using low-dose (5 J/cm2, 100 mW/cm2) or high-dose (30 J/cm2, 100 mW/cm2) irradiation, and the expression of thioredoxin was measured by Western blotting. An MTT assay was used to assess cell growth following a low dose of multiple irradiations. Cell death was examined by Western blotting for caspase-3 and PARP. Immunofluorescence double staining using annexin V and propidium iodine was also performed. Results: Expression of thioredoxin was only observed following low-dose exposure ALA-PDT. Multiple low-dose exposure ALA-PDT significantly proliferated cell growth. With high-dose exposure ALA-PDT, caspase-3 and PARP expression were seen, and cell death due to apoptosis and/or necrosis was observed, but thioredoxin was barely detected. Conclusion: Low-dose exposure ALA-PDT increased the expression of thioredoxin and facilitated the growth of HSC-5 cells. [ABSTRACT FROM AUTHOR]

Abstract: The first example of the synthesis of a peptide incorporating 5-aminolaevulinic acid (5-ALA) using standard Fmoc solid-phase chemistry is reported. The synthesised peptide contains residues 52–58 of the cell-permeable peptide Penetratin and represents a prototype for the enhanced topical delivery of 5-ALA using such oligopeptide vectors. Effective intracellular conversion of the peptide to the endogenous photosensitiser, protoporphyrin IX, is observed in PAM212 cells, thus demonstrating the potential of this approach for the development of novel peptide prodrugs for use in photodynamic therapy. [Copyright &y& Elsevier]