Photodynamic therapy for acne vulgaris: a critical review from basics to clinical practice: part II. Understanding parameters for acne treatment with photodynamic therapy

Effectiveness of 5-aminolevulinic acid photodynamic therapy in treating dissecting cellulitis of the scalp and pathological changes in skin lesions: A retrospective study

BACKGROUND

Dissecting cellulitis of the scalp (DCS) has a significant impact on the physical well-being and body image of the patient. Since DCS often responds poorly to conventional treatments, there is a need to identify alternative treatment strategies. This study aimed to explore the effectiveness of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in treating DCS.

METHODS

Twelve male patients with DCS treated solely with ALA-PDT between June 2022 and June 2023 at our institution were enrolled in this study. Two patients underwent a biopsy before and after treatment for comparison. The efficacy of the treatments was assessed 10 days after treatment by evaluating the symptom scores recorded on medical records and by assessing the photographs acquired before and after treatment. In addition, the impact of the treatment on pain relief and median recurrence rate were also extracted.

RESULTS

Out of the 12 enrolled patients, the majority of the patients (75%) had a significant reduction in the nodules or abscesses. The pain relief was significant in 3 patients (25%), and moderate in 7 patients (58.3%). For the subcutaneous sinus tract symptoms, 3 patients (27.3%) showed moderate improvement, and 7 (63.6%) had a mild improvement. Six patients (75%) had mild improvement in their alopecia. The pathology results showed a decrease in the number of lymphocytes, macrophages, and neutrophils within the skin lesions following the administration of ALA-PDT.

CONCLUSION

ALA-PDT can effectively reduce the DCS symptoms and the number of lymphocytes, macrophages, and neutrophils within the skin lesions.

The role of current synthetic and possible plant and marine phytochemical compounds in the treatment of acne

Acne is a long-standing skin condition characterized by plugged hair follicles due to the accumulation of dead skin cells, sebum, and Propionibacterium acnes (P. acnes) bacteria, causing inflammation, and the formation of pimples or lesions. Acne was recognized in the ancient times by the ancient Egyptians, Greeks, and Romans. Since ancient times, folk medicine from different cultures have comprised herbal and natural products for the treatment of acne. Current acne medications include antibiotics, keratolytics, corticosteroids, in addition to hormonal therapy for women. However, these conventional drugs can cause some serious side effects. And therefore, seeking new safe treatment options from natural sources is essential. Plants can be a potential source of medicinal phytochemicals which can be pharmacologically active as antibacterial, antioxidant, anti-inflammatory, keratolytic and sebum-reducing. Organic acids, obtained from natural sources, are commonly used as keratolytics in dermatology and cosmetology. Most of the promising phytochemicals in acne treatment belong to terpenes, terpenoids, flavonoids, alkaloids, phenolic compounds, saponins, tannins, and essential oils. These can be extracted from leaves, bark, roots, rhizomes, seeds, and fruits of plants and may be incorporated in different dosage forms to facilitate their penetration through the skin. Additionally, medicinal compounds from marine sources can also contribute to acne treatment. This review will discuss the pathogenesis, types and consequences of acne, side effects of conventional treatment, current possible treatment options from natural sources obtained from research and folk medicine and possible applied dosage forms.

Reactive Oxygen Species (ROS)-Mediated Antibacterial Oxidative Therapies: Available Methods to Generate ROS and a Novel Option Proposal

The increasing emergence of multidrug-resistant (MDR) pathogens causes difficult-to-treat infections with long-term hospitalizations and a high incidence of death, thus representing a global public health problem. To manage MDR bacteria bugs, new antimicrobial strategies are necessary, and their introduction in practice is a daily challenge for scientists in the field. An extensively studied approach to treating MDR infections consists of inducing high levels of reactive oxygen species (ROS) by several methods. Although further clinical investigations are mandatory on the possible toxic effects of ROS on mammalian cells, clinical evaluations are extremely promising, and their topical use to treat infected wounds and ulcers, also in presence of biofilm, is already clinically approved. Biochar (BC) is a carbonaceous material obtained by pyrolysis of different vegetable and animal biomass feedstocks at 200-1000 °C in the limited presence of O2. Recently, it has been demonstrated that BC's capability of removing organic and inorganic xenobiotics is mainly due to the presence of persistent free radicals (PFRs), which can activate oxygen, H2O2, or persulfate in the presence or absence of transition metals by electron transfer, thus generating ROS, which in turn degrade pollutants by advanced oxidation processes (AOPs). In this context, the antibacterial effects of BC-containing PFRs have been demonstrated by some authors against Escherichia coli and Staphylococcus aureus, thus giving birth to our idea of the possible use of BC-derived PFRs as a novel method capable of inducing ROS generation for antimicrobial oxidative therapy. Here, the general aspects concerning ROS physiological and pathological production and regulation and the mechanism by which they could exert antimicrobial effects have been reviewed. The methods currently adopted to induce ROS production for antimicrobial oxidative therapy have been discussed. Finally, for the first time, BC-related PFRs have been proposed as a new source of ROS for antimicrobial therapy via AOPs.

Photodynamic therapy alone or in combination to counteract bacterial infections

INTRODUCTION

Antibacterial photodynamic therapy presents a promising alternative to antibiotics, with potential against multidrug-resistant bacteria, offering broad-spectrum action, reduced resistance risk, and improved tissue selectivity.

AREAS COVERED

This manuscript reviews patent literature in the field of antibacterial photodynamic therapy through the period of 2019-2023. All data are from the US and European patent databases and SciFinder.

EXPERT OPINION

Antibacterial photodynamic therapy (PDT) is an appealing approach for treating bacterial infections, especially biofilm-related ones, by releasing reactive oxygen species (ROS) upon light activation. Its success is driven by a growing variety of photosensitizers (PSs) with tailored properties, like water solubility, controllable surface charge, and ROS generation efficiency. Among them, Aggregation Induced Emission (AIE)-type PSs are promising, demonstrating enhanced efficacy when aggregated in biological environments. However, the penetration of pristine PSs into bacterial biofilms within deep tissues or complex anatomical regions is limited, reducing their antibacterial effectiveness. To address this, nanotechnology has been integrated into antibacterial PDT to synthesize various nano-PSs. This adaptability allows seamless integration with other antimicrobial treatments, offering a comprehensive approach to combat localized infections, especially in dentistry and dermatology. By combining PSs with complementary therapies, antibacterial PDT offers a multifaceted strategy for effective microbial control and management.

5-aminolevulinic acid photodynamic therapy using 560-1200 nm followed by 420-1200 nm broadband light in the treatment of moderate-to-severe acne

BACKGROUND

Moderate-to-severe acne vulgaris, which is a chronic inflammatory skin disease, seriously impacts millions of people. However, traditional therapies may cause severe adverse reactions that are unacceptable to many patients, thus limiting the further application of these therapies. Novel therapeutic approaches to effectively treat moderate-to-severe acne vulgaris with minimal adverse reactions are urgently needed. In this retrospective study, we investigated the efficacy and adverse reactions of photodynamic therapy (PDT) using 560-1200 nm followed by 420-1200 nm broadband light (BBL).

METHODS

Twenty-four patients with moderate-to-severe acne vulgaris were included in the study and all patients expressed a strong desire for beauty. After aminolevulinic acid (ALA) gel applied, the entire face was sequentially irradiated by using BBL with a 560 nm cut-off filter (560-1200 nm), followed by BBL with a 420 nm cut-off filter (420-1200 nm). The clinical efficacy was evaluated by the proportion of patients achieving cured response and excellent response (effective rate), based on the percentage of lesions reduction (treatment rate). The fluorescent images and photographs of acne vulgaris were recorded. Pain and other common local adverse reactions during the treatment were also recorded and evaluated.

RESULTS

In patients with moderate acne, the mean treatment rates were 57.74 ± 16.40 (%) and 87.40 ± 8.521 (%) at the 6th week and 12th week of treatment, respectively. In patients with severe acne, the mean treatment rates were 60.95 ± 12.06 (%) and 85.04 ± 9.115 (%) at the 6th week and 12th week of treatment, respectively. At the 6th and 12th weeks of treatment, the effective rates of patients were 20.00 % and 93.33 % in patients with moderate acne, and 0.000 % and 88.89 % in patients with severe acne, respectively. Pain scores were significantly higher in patients with severe acne compared to patients with moderate acne when receiving 560-1200 nm BBL-PDT. Additionally, patients when receiving 420-1200 nm BBL-PDT exhibited significantly higher pain scores than those when receiving 560-1200 nm BBL-PDT. The degree of erythema was more severe in patients with severe acne than in those with moderate acne. The pigmentation was observed in one patient with moderate acne and one patient with severe acne.

CONCLUSION

The 560-1200 nm and 420-1200 nm BBL-PDT therapy can effectively treat moderate-to-severe acne vulgaris with tolerable adverse reactions, providing a new option for patients with higher esthetic requirements.

A preliminary study on the evaluation of photodynamic diagnosis for acne inflammatory skin lesions

OBJECTIVE

This study aimed to observe the fluorescence characteristics of acne inflammatory skin lesions in 5-aminolevulinic acid-based photodynamic diagnosis (ALA-PDD), and discuss the viability of using ALA-PDD to evaluate acne inflammatory skin lesions and explore the advantages of predicting subclinical skin lesions.

METHODS

The OBSERV facial skin detector collected photographs of 20 patients before and after optical intra-tissue fiber irradiation photodynamic therapy (OFI-ALA-PDT) in both ALA-PDD and white light patterns. The patients were treated once a week for four consecutive weeks in order to analyze the correlation between the two patterns in recognizing inflammatory skin lesions.

RESULTS

Before and after treatment, there was no significant difference between the two patterns for recognizing acne inflammatory skin lesions (p > 0.05). Both patterns demonstrated a strong correlation (r > 0.90) for the recognition of various types of inflammatory skin lesions at different treatment stages.

CONCLUSION

ALA-PDD is a feasible method for evaluating acne inflammatory lesions, guiding treatment and judging efficacy. It has advantages in predicting subclinical skin lesions and deserves further study.

The quantitative analysis of low-concentration (2%) ALA-PDT assisted with Q-switch 1064-nm Nd:YAG laser for acne vulgaris treatment

Conventional 5-aminolevulinic acid-photodynamic (ALA-PDT) therapy (10-20%) has been widely applied for moderate-to-severe acne. The aim of this study is to investigate the effects of non-ablative Q-switched 1064-nm Nd:YAG laser-assisted ALA-PDT with low concentration (2%) on the treatment of acne vulgaris. Enrolled patients were randomly assigned to 2 groups. One group received combined therapy of 2% ALA-PDT and non-ablative Q-switched 1064-nm Nd:YAG laser, and the other received only 2% ALA-PDT. Patients in each group had received 3-session treatments with 4-week intervals (week 0, 4, and 8). Sebum secretion, melanin index, erythema index, and transepidermal water loss (TEWL) were assessed at week 2, 8, 12, and 24. VISIA® skin image system score and global esthetic improvement scale (GAIS) were also evaluated. Twenty-four participants were enrolled and evenly randomized to two groups. Significant improvement in sebum secretion was noted in combined therapy group compared to the monotherapy group at week 12 (37.5% versus 16.3%), and the improvement would still be noted until week 24 (18.3% versus 17.4%). Combined group also showed more severe melanin index and erythema index after treatment. For VISIA® skin analysis, patients in combined group had better percentile ranking in porphyrins and red-light images. There were no significant differences in GAIS at the end of the follow-up between each group, whereas higher proportion of satisfaction was noted in combined group at week 2. With the assistance of laser, low concentrations (2%) of 5-ALA can provide effective phototoxic reactions in treating acne vulgaris. The satisfaction of patients is high with acceptable adverse effects.

Effect of various types of photodynamic therapy on inflammatory and non-inflammatory lesions in patients with acne: A network meta-analysis of randomized controlled trials

BACKGROUND

Recent studies have demonstrated that photodynamic therapy (PDT) is safe and effective in treating acne vulgaris. The present study aimed to evaluate various PDTs on inflammatory and non-inflammatory lesions in patients with acne by a network meta-analysis (NMA) of randomized controlled trials (RCTs).

METHODS

The researchers of this paper searched PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception to March 2022 to identify suitable RCTs. The included studies were evaluated for methodological quality using the Cochrane bias risk assessment tool. Twenty-one RCTs were included, with a total sample size of 898 participants.

RESULTS

Network meta-analysis (NMA) revealed that indocyanine green (ICG) + near-infrared (NIR) diode laser, ICG+830 nm light-emitting diode (LED), indole-3-acetic acid (IAA) + 520 nm LED, and 5-aminolevulinic acid (ALA) + sunlight demonstrated obvious curative effects in patients with acne vulgaris. Importantly, ICG+NIR diode laser provided the greatest improvement in both inflammatory and non-inflammatory acne lesions (surface under the cumulative ranking curve [SUCRA]: 84.4% and 93.5%, respectively).

CONCLUSIONS

Based on the NWM and SUCRA ranking, ICG + NIR diode laser can be considered more effective in treating acne than the other PDTs of the RCTs. However, this conclusion should be interpreted with caution due to the limitations of the present study.

What Are Reactive Oxygen Species, Free Radicals, and Oxidative Stress in Skin Diseases?

Oxygen in the atmosphere is a crucial component for life-sustaining aerobic respiration in humans. Approximately 95% of oxygen is consumed as energy and ultimately becomes water; however, the remaining 5% produces metabolites called activated oxygen or reactive oxygen species (ROS), which are extremely reactive. Skin, the largest organ in the human body, is exposed to air pollutants, including diesel exhaust fumes, ultraviolet rays, food, xenobiotics, drugs, and cosmetics, which promote the production of ROS. ROS exacerbate skin aging and inflammation, but also function as regulators of homeostasis in the human body, including epidermal keratinocyte proliferation. Although ROS have been implicated in various skin diseases, the underlying mechanisms have not yet been elucidated. Current knowledge on ROS-related and oxidative stress-related skin diseases from basic research to clinical treatment strategies are discussed herein. This information may be applied to the future treatment of skin diseases through the individual targeting of the ROS generated in each case via their inhibition, capture, or regulation.

Optimizing treatment of acne with photodynamic therapy (PDT) to achieve long-term remission and reduce side effects. A prospective randomized controlled trial

Photodynamic therapy with methyl aminolevulinate (MAL-PDT) is an effective treatment of acne vulgaris, but is associated with side effects. We performed a prospective randomized split-face study aimed at optimizing MAL-PDT treatment. Patients (n = 33) were randomized to two or four treatments of PDT with MAL on one cheek and placebo vehicle on the other cheek, 1-2 weeks apart. A 1.5-h pre-treatment with the MAL cream was followed by illumination with red light (20 J/cm²). Assessments were performed before treatment and 4, 10, and 20 weeks after the last treatment. In comparison to baseline, the number of inflammatory lesions at 20 weeks on cheeks treated with MAL-PDT showed a relative decrease of 74% in the group with two treatments and 85% in the group with four treatments. This new treatment regimen for both MAL-PDT and red-light-only PDT, with shortened pre-treatment and reduced light dose, could be an effective modality.

A prospective study of the effect of fire micro-needling plus 5% topical ALA-PDT for the treatment of dissecting cellulitis of the scalp

BACKGROUND

Different therapies have been used for dissecting cellulitis of the scalp (DCS) with poor results. Topical 5-aminolaevulinic acid photodynamic therapy (ALA-PDT) is effective for many inflammatory skin diseases.

OBJECTIVES

To evaluate the efficacy and safety of fire micro-needling plus 5% ALA-PDT on DCS.

METHODS

Forty-two male DCS patients were enrolled and treated by four sessions of fire micro-needling plus 5% ALA-PDT (occlusion time: 3 h, 100 mW/cm² for 20-32 min, 633 ± 10 nm LED) with an interval of 1-2 weeks. The reduction of lesions was evaluated at each follow-up visit. The patients` symptoms were evaluated by Dermatology Life Quality Index (DLQI). All of the side effects were recorded.

RESULTS

Forty-one DCS patients finished the treatments and the marked effective rate (MER) reached 65.85%. Ten patients (24.39%) were cured and 17 patients (41.46%) achieved excellent improvement. The median of lesion numbers decreased significantly from 25 to 7 (p < 0.001) with DLQI from 13 to 2 (p < 0.001). Although all the ten cured patients had a relapse during the 12-month follow-up, 5/10 patients had a remission of more than 6 months. All the patients tolerated PDT well with mild adverse effects.

CONCLUSIONS

Fire micro-needling plus 5% ALA-PDT is effective for Chinese male DCS patients without the need to take systemic drugs.

CRISPR/Cas9 mediated T7 RNA polymerase gene knock-in in E. coli BW25113 makes T7 expression system work efficiently

T7 Expression System is a common method of ensuring tight control and high-level induced expression. However, this system can only work in some bacterial strains in which the T7 RNA Polymerase gene resides in the chromosome. In this study, we successfully introduced a chromosomal copy of the T7 RNA Polymerase gene under control of the lacUV5 promoter into Escherichia coli BW25113. The T7 Expression System worked efficiently in this mutant strain named BW25113-T7. We demonstrated that this mutant strain could satisfactorily produce 5-Aminolevulinic Acid via C5 pathway. A final study was designed to enhance the controllability of T7 Expression System in this mutant strain by constructing a T7 Promoter Variants Library. These efforts advanced E. coli BW25113-T7 to be a practical host for future metabolic engineering efforts.

A split-face clinical trial of conventional red-light photodynamic therapy versus daylight photodynamic therapy for acne vulgaris

BACKGROUND

Photodynamic therapy (PDT) is considered an effective treatment for acne vulgaris. A significant drawback is pain during illumination. Daylight PDT (DL-PDT) is more tolerable.

OBJECTIVE

To assess and compare the efficacy and tolerability of DL-PDT and C-PDT for acne vulgaris through a prospective split-face trial.

METHODS AND MATERIALS

Fifteen patients underwent 4 treatment sessions at 3-week intervals. First, 5-aminolevulinic acid (ALA) was applied to the entire face, after which the face was divided into 2 symmetrical areas: The right side was exposed to sunlight, and the left half was illuminated with red light. Photographs were obtained and evaluated by two dermatologists blinded to the study protocol. The patients reported side effects and downtime.

RESULTS

There was a statistically significant decrease in the number and percent change of inflammatory and non-inflammatory lesions on both sides. Adverse effects were markedly decreased on the DL-PDT side compared to the C-PDT side (p < .01). The average downtime duration was longer for the C-PDT side (p < .001).

CONCLUSION

DL-PDT was at least as effective as C-PDT with fewer adverse effects and a shorter downtime duration.

The efficacy and safety of 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) as an adjunct therapy for symptoms in patients with dissecting cellulitis of the scalp: A retrospective study

BACKGROUND

Medicinal therapies such as systemic retinoids and antibiotics have shown efficacy in the treatment of dissecting cellulitis of the scalp (DCS), but refractory cases are common. 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) has been successfully used in medicine-resistant cases in recent years.

METHODS

A total of 12 patients who received ALA-PDT in addition to formally failed medicinal therapies were interviewed by telephone regarding improvement of symptoms, satisfaction, and side effects.

RESULTS

Overall, 58.3 % patients achieved greater than 50 % improvement of at least one symptom, and 16.7 % had little improvement for any symptom. The proportion of patients who had greater than 50 % improvement for pain, pruritus, swelling and suppuration were 36.4 %, 66.7 %, 33.3 % and 58.3 % respectively. 41.7 % patients were either satisfied or very satisfied with the ALA-PDT. The side effects were mainly pain and crusting that were mostly mild and recovered quickly.

CONCLUSION

ALA-PDT was safe and partially effective in reducing DCS symptoms as an adjunct to systemic medicinal therapies.

Visible light. Part I: Properties and cutaneous effects of visible light

Approximately 50% of the sunlight reaching the Earth's surface is visible light (400-700 nm). Other sources of visible light include lasers, light-emitting diodes, and flash lamps. Photons from visible light are absorbed by photoreceptive chromophores (e.g., melanin, heme, and opsins), altering skin function by activating and imparting energy to chromophores. Additionally, visible light can penetrate the full thickness of the skin and induce pigmentation and erythema. Clinically, lasers and light devices are used to treat skin conditions by utilizing specific wavelengths and treatment parameters. Red and blue light from light-emitting diodes and intense pulsed light have been studied as antimicrobial and anti-inflammatory treatments for acne. Pulsed dye lasers are used to treat vascular lesions in adults and infants. Further research is necessary to determine the functional significance of visible light on skin health without confounding the influence of ultraviolet and infrared wavelengths.

Cationic zinc (II) phthalocyanine nanoemulsions for photodynamic inactivation of resistant bacterial strains

BACKGROUND

The growing emergence of microbial resistance to antibiotics represents a worldwide challenge. Antimicrobial photodynamic inactivation (aPDI) has been introduced as an alternative technique, especially when combined with nanotechnology. Therefore, this study was designed to investigate the therapeutic merits of combined aPDI and nanoemulsion in infections caused by resistant bacterial strains.

METHODS

Cationic zinc (II) phthalocyanine nanoemulsions (ZnPc-NE) were prepared using isopropyl myristate (IPM) as oil phase, egg phosphatidylcholine (egg PC) as emulsifier, and N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB). Nanoemulsions were characterized for particle size, polydispersity, zeta potential, viscosity, and skin deposition. The in-vitro aPDI was investigated on human resistant pathogens; gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and gram-negative Multidrug-resistant strain of Escherichia coli (MDR E. coli), under different experimental conditions. In addition, in-vivo model of abrasion wound infected by MDR E. coli was induced in rats to investigate the therapeutic potential of the selected formulation.

RESULTS

It was evident that the selected ZnPc formulation (20 % IPM, 2 % egg PC and 0.5 % CTAB) displayed a particle size of 209.9 nm, zeta potential +73.1 mV, and 23.66 % deposition of ZnPc in skin layers. Furthermore, the selected formulation combined with light achieved almost 100 % eradication of the two bacterial strains, with superior bacterial load reduction and wound healing propertiesin-vivo, compared to either the nanoemulsion formulation or laser alone.

CONCLUSION

ZnPc nanoemulsion improved antimicrobial photodynamic therapy in inactivating resistant bacterial infections and provided a promising therapeutic means of treating serious infections, and hence could be applied in diseases caused by other bacterial strains.

The effects of ALA-PDT on microbiota in pilosebaceous units of patients with severe acne: A metagenomic study

BACKGROUND

5-aminolevulinic acid mediated photodynamic therapy (ALA-PDT) is increasingly used to control severe acne. However, its impact on skin microbiota remains uncertain.

OBJECTIVES

We aimed to compare the makeup, diversity, and function of the microbiota in pilosebaceous units of patients with severe acne before and after ALA-PDT.

METHODS

A longitudinal cohort study was performed on 11 participants with severe facial acne. All patients were given 5%ALA-PDT every two weeks for three sessions in total. The contents of lesions were sampled for metagenomic sequencing at baseline and two weeks after the first ALA-PDT session.

RESULTS

Cutibacterium acnes was the most dominant species followed by Staphylococcus epidermidis and Pseudomonas fluorescens. Treatment with ALA-PDT led to clinical improvements in acne severity concurrent with a significant reduction in the relative abundance of C. acnes, while P. fluorescens increased significantly after ALA-PDT. No significant change was identified in other species. ALA-PDT administration was associated with an increased microbiota diversity and reductions in the relative abundance of the functional genes involved in energy metabolism and DNA replication.

CONCLUSIONS

ALA-PDT plays a therapeutic role by killing C. acnes, increasing P. fluorescens and the microbiome diversity, while inhibiting the function of microbiota in pilosebaceous units of severe acne.

Dissecting Cellulitis of the Scalp: A Review and Case Studies of Surgical Reconstruction

Dissecting cellulitis of the scalp (DCS) is a part of the follicular occlusion tetrad (hidradenitis, acne conglobata, and pilonidal disease). It is a spectrum disorder that can be severe and refractory to medical management. The authors describe 3 such cases successfully treated with surgical resection and reconstruction and present a scoring system for timely referral of such patients to a reconstructive surgical team.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 1: treatment delivery and established indications - actinic keratoses, Bowen's disease and basal cell carcinomas

Topical photodynamic therapy (PDT) is a widely approved therapy for actinic keratoses, Bowen's disease (squamous cell carcinoma in situ), superficial and certain thin basal cell carcinomas. Recurrence rates when standard treatment protocols are used are typically equivalent to existing therapies, although inferior to surgery for nodular basal cell carcinoma. PDT can be used both as lesional and field therapies and has the potential to delay/reduce the development of new lesions. A protocol using daylight to treat actinic keratoses is widely practised, with conventional PDT using a red light after typically a 3-h period of occlusion employed for other superficial skin cancer indications as well as for actinic keratoses when daylight therapy is not feasible. PDT is a well-tolerated therapy although discomfort associated with conventional protocol may require pain-reduction measures. PDT using daylight is associated with no or minimal pain and preferred by patient. There is an emerging literature on enhancing conventional PDT protocols or combined PDT with another treatment to increase response rates. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical PDT in dermatology, prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 2: emerging indications - field cancerization, photorejuvenation and inflammatory/infective dermatoses

In addition to approved indications in non-melanoma skin cancer in immunocompetent patients, topical photodynamic therapy (PDT) has also been studied for its place in the treatment of, as well as its potential to prevent, superficial skin cancers in immune-suppressed patients, although sustained clearance rates are lower than for immune-competent individuals. PDT using a nanoemulsion of ALA in a daylight or conventional PDT protocol has been approved for use in field cancerization, although evidence of the potential of the treatment to prevent new SCC remained limited. High-quality evidence supports a strong recommendation for the use of topical PDT in photorejuvenation as well as for acne, refractory warts, cutaneous leishmaniasis and in onychomycosis, although these indications currently lack approvals for use and protocols remain to be optimized, with more comparative evidence with established therapies required to establish its place in practice. Adverse events across all indications for PDT can be minimized through the use of modified and low-irradiance regimens, with a low risk of contact allergy to photosensitizer prodrugs, and no other significant documented longer-term risks with no current evidence of cumulative toxicity or photocarcinogenic risk. The literature on the pharmacoeconomics for using PDT is also reviewed, although accurate comparisons are difficult to establish in different healthcare settings, comparing hospital/office-based therapies of PDT and surgery with topical ointments, requiring inclusion of number of visits, real-world efficacy as well as considering the value to be placed on cosmetic outcome and patient preference. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical photodynamic therapy in Dermatology prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

Comparative Study Of Photodynamic Therapy With Riboflavin-Tryptophan Gel And 13% 5-Aminolevulinic Acid In The Treatment Of Mild To Moderate Acne Vulgaris

Background

Non-invasive photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) has been used as an alternative acne treatment for many years. Riboflavin and tryptophan are newly introduced photosensitizers.

Objective

To compare the efficacy of PDT with riboflavin-tryptophan (RT) gel with that of 13% ALA for the treatment of facial acne.

Methods

We performed a double-blind, split-face study of 37 subjects with mild to moderate facial acne vulgaris. RT gel was applied to half of the face, and 13% ALA was applied to the other half. Then, the whole face was irradiated using a blue light-emitting diode for 20 mins. Four treatment sessions were performed over a 4-week duration, at 1-week interval. The acne lesion counts and acne severity were assessed. Sebum secretion, Propionibacterium acne colonization, pore size, and skin texture were also evaluated.

Results

PDT with RT gel demonstrated good efficacy, non-inferior to ALA for acne treatment, with a significant reduction in acne lesion counts, severity grading, porphyrin, and sebum output. The pore size and skin texture were improved. Side-effects were minimal and well tolerated in all subjects.

Conclusion

PDT therapy with RT gel is an effective alternative treatment for acne vulgaris.

Daylight photodynamic therapy with 5-aminolevulinic acid 5% gel for the treatment of mild-to-moderate inflammatory acne

BACKGROUND

Acne vulgaris is a chronic inflammatory disease that frequently occurs in adolescence. This common condition is often treated with topical or systemic therapies according to severity. Photodynamic therapy (PDT) with topical delta-aminolaevulinic acid is a novel drug-sparing, but time-consuming approach. Recently, sunlight exposure has been considered a quicker, safer, cheaper and more agreeable alternative light source for PDT, but efficacy has only been proven in the oncological field. This study aimed to evaluate the efficacy and tolerability of daylight PDT (DL-PDT) for the treatment of inflammatory acne vulgaris of face, chest and trunk lesions.

METHODS

Twenty patients with mild-to-moderate acne vulgaris were enrolled and treated with a topical gel based on 5% delta-aminolaevulinic acid, administered 4 times at 14-day intervals. Efficacy was assessed with mean lesion count, Physician Global Assessment (PGA), Investigator's Global Assessment (IGA) and patients' self-assessment (10-point scale).

RESULTS

Compared to T0, mean inflammatory lesions count decreased in all patients at FU1, from 16.7±4.4 to 5.2±3.3 (P). No adverse events were reported, and no patients were lost to follow-up. PGA results of "excellent" or "good" improvement were reported in 95% at T3 and 90% at FU1. Patients' self-assessments was 7.6±1.0 (T3). Discomfort was 0.5±0.2 (T3 and FU1).

CONCLUSIONS

DL-PDT seems to be an effective and tolerable therapy for the treatment of mild-to-severe inflammatory acne. This novel regimen seems to be a viable option in the panorama of acne therapies.

[Light-based inflammatory acne treatments]

Light-based acne treatments may represent a new emerging treatment for acne that does not increase the risk of bacterial resistance and they may be potentially effective with a favorable safety profile. Current data show that photodynamic therapy reduces inflammatory lesions and significantly improves acne. However, there is no consensus on the optimal implementation in the treatment of acne. In addition to topically applied photodynamic therapy, intense pulsed light, pulsed dye lasers, potassium-titanyl-phosphate lasers, infrared diode lasers, broad-spectrum continuous-wave light sources (red light, blue-red light) have been introduced as alternative treatments. Since well-designed studies to evaluate their efficacy versus traditional medical therapies are lacking and standardized regimens have not been agreed upon, procedures including laser, intense pulsed light, and photodynamic therapy should currently not be considered first-line treatment for inflammatory acne.

Optimization of hydrogel containing toluidine blue O for photodynamic therapy in treating acne

Antibiotics and photodynamic therapy (PDT) are widely employed in curing acne. However, antibiotics as an effective treatment would lead to bacterial resistance and severe side effects. In this study, we aimed to develop a novel TBO hydrogel, which could prolong the retention time of photosensitizer (TBO) at the lesion site and improve therapeutic effect. In vitro antibacterial experiments (against Staphylococcus aureus and Escherichia coli), the response surface methodology was used to optimize the formulation of TBO hydrogel. The results indicated that the optimal formulation was 0.5% (v/v) carbomer, 0.01 mg/mL TBO, 0.5% (v/v) ethanol concentration, 0.5% (v/v) Tween 80, the mass ratio of NaOH to carbomer of 0.4 (w/w). The TBO hydrogel formulation showed the strong antibacterial activity for Propionibacterium acnes. The stability, pH, and antibacterial activity of TBO hydrogel did not significantly change under 4 °C, 25 °C, and 40 °C during 6-week storage. Furthermore, TBO combined with carbomer hydrogel showed the 51.28% (4 h) and 69.80% (24 h) release. In summary, the hydrogel TBO might be a vital therapeutic strategy to promote the PDT applied in the topical therapy of acne. Graphical abstract A TBO hydrogel for photodynamic therapy in the treatment of acne.

Highly efficient and biocompatible nanoparticle-based photosensitizer for treatment of acne vulgaris

Aim: Nanoparticle-based photosensitizers containing silver core and mesoporous silica shell with hematoporphyrin IX embedded were developed to treat vulgaris photodynamically. Materials & methods: The hybrid photosensitizers were dispersed in 30% polyethylene glycol (PEG-200) solution and used for the photodynamic treatment of Staphylococcus epidermidis and Propionibacterium acnes under the illumination of a portable LED (∼410 nm). Results: After a 5 min illumination by the LED, the hybrid photosensitizers of 50 μg/ml displayed killing efficacy of approximately 5-log for S. epidermidis and approximately 4-log for P. acnes. Results indicated that hybrid photosensitizers in PEG-200 matrix perform better than in deionized (DI) water (∼1-log increase in killing efficacy).Conclusion: Under short illumination of a portable LED, hybrid photosensitizers demonstrated immense potential for treatment of acne vulgaris without involving antibiotics.

Fluorescence Resonance Energy Transfer-Based Wash-Free Bacterial Imaging and Antibacterial Application Using a Cationic Conjugated Polyelectrolyte

The increase in bacterial infection and antibiotic resistance has posed a severe threat to the human health. This threat has warranted an imperative demand for the development of a new and effective bactericidal material to eradicate the antibiotic-resistant pathogenic bacteria. In this work, we report the wash-free imaging of Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria using cationic conjugated polyelectrolyte[9,9-bis(6'-methylimidazoliumbromide)hexyl-fluorene- co-4,7-(2,1,3-benzothiadiazole)] (PFBT-MI) based on aggregation-induced fluorescence resonance energy transfer (FRET). Cationic imidazolium group strapped on the polymer side chain not only increases its solubility in water but also helps in binding with the negatively charged bacterial membrane via electrostatic interactions to turn on its bright yellow emission. The change in the fluorescence color of conjugated polyelectrolyte in the presence of bacteria could be visualized very easily via naked eyes under a UV lamp (365 nm). Furthermore, the antibacterial activity of PFBT-MI against both S. aureus and E. coli was observed because of the amphiphilic nature of the conjugated polyelectrolyte which in turn is due to the presence of ionic functionality and conjugated polymer backbone that can intercalate very proficiently into the bacterial membrane, which disrupts the membrane integrity and thus results in toxicity. Morphologically, the membrane damage was perceived via field emission scanning electron microscopy (FESEM) images, which clearly indicated the disruption of cell membrane upon exposure to PFBT-MI. The PFBT-MI acts as an effective antibacterial agent, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) value of (30 μM or 23.7 μg/mL) and (60 μM or 47.7 μg/mL) for S. aureus and for E. coli (60 μM or 47.7 μg/mL) and (100 μM or 79 μg/mL), respectively. Moreover, PFBT-MI shows less cytotoxicity against mammalian cells at concentration greater than MIC.

Comparison of efficacy of aminolaevulinic acid photodynamic therapy vs. adapalene gel plus oral doxycycline for treatment of moderate acne vulgaris-A simple, blind, randomized, and controlled trial

BACKGROUND

Although progress has been made in the study of photodynamic therapy for acne, studies using current recommended therapies as active comparators are lacking.

METHODS

Randomized, controlled trial involving 46 patients with moderate inflammatory facial acne, 23 patients received two sessions of PDT separated by 2 weeks (ALA 20% incubated 1.5 hours before red light irradiation with 37 J/cm² fluence) and 23 patients received doxycycline 100 mg/d plus adapalene gel 0.1%. In both groups, from the sixth week, we started adapalene gel 0.1% as maintenance therapy until 12 weeks of follow-up. Primary end point was the reduction of acne lesions at the 6-week follow-up, which was evaluated by 2 investigators blinded to the intervention.

RESULTS

The median percent reductions in noninflammatory lesion count (P = 0.013) and total lesions (P = 0.038) at 6 weeks was found to be significantly higher in the group receiving PDT. At 12 weeks there was a greater reduction of inflammatory lesions in PDT group with 84% vs. 74% for group who received doxycycline plus adapalene (P = 0.020) as well as in reducing total lesions with 79% vs. 67% respectively (P = 0.026). No severe side-effects were observed for either therapy.

CONCLUSIONS

ALA-PDT offers promise as an alternative treatment for moderately severe inflammatory acne that has a higher effectiveness than the combination of doxycycline and adapalene gel in reducing noninflammatory and total lesions at 6 weeks. There were significantly superior reductions at 12 weeks in the combination of PDT group followed by adapalene gel in total, inflammatory, and noninflammatory lesions.

A review of diagnosis and treatment of acne in adult female patients

This review focuses on the treatment options for adult female patients with acne. Acne in adult female patients may start during adolescence and persist or have an onset in adulthood. Acne has various psychosocial effects that impact patients’ quality of life. Treatment of acne in adult women specifically has its challenges due to the considerations of patient preferences, pregnancy, and lactation. Treatments vary widely and treatment should be tailored specifically for each individual woman. We review conventional therapies with high levels of evidence, additional treatments with support from cohort studies and case reports, complementary and/or alternative therapies, and new agents under development for the treatment of patients with acne.

Light therapies for acne: abridged Cochrane systematic review including GRADE assessments

We undertook a Cochrane review of randomized controlled trials (RCTs) evaluating the effects of light-based interventions for acne vulgaris. We searched the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, ISI Web of Science and grey literature sources (September 2015). We used the Grading of Recommendations Assessment, Development and Evaluation Working Group approach to assess the quality of evidence (QoE). We included 71 RCTs (4211 participants, median sample size 31). Results from a single study (n = 266, low QoE) showed little or no difference in effectiveness on participants' assessment of improvement between 20% aminolaevulinic acid (ALA) photodynamic therapy (PDT), activated by blue light, vs. vehicle plus blue light, whereas another study (n = 180) comparing ALA-PDT (red light) concentrations showed that 20% ALA-PDT was no more effective than 15% ALA-PDT but better than 10% and 5% ALA-PDT. Pooled data from three studies (n = 360, moderate QoE) showed that methyl aminolaevulinate PDT, activated by red light, had a similar effect on changes in lesion counts vs. placebo cream with red light. Several studies compared yellow light with placebo or no treatment, infrared light with no treatment, gold microparticle suspension with vehicle and clindamycin/benzoyl peroxide (C/BPO) combined with pulsed dye laser with C/BPO alone. None of these showed any clinically significant effects. Most studies reported adverse effects, but inadequately, with scarring reported as absent, and blistering only in studies on intense pulsed light, infrared light and PDT (very low QoE). Carefully planned studies, using standardized outcome measures and common acne treatments as comparators, are needed.

Topical 5-aminolevulinic photodynamic therapy with red light vs intense pulsed light for the treatment of acne vulgaris: A spilit face, randomized, prospective study

5-Aminolevulinic acid photodynamic therapy (ALA-PDT) has been an effective method for treating acne vulgaris. Red light is the most widely used light source while Intense pulsed lights (IPL) is reported effective and well-tolerated. The purpose of this study was to evaluate the efficacy and adverse reactions of ALA-PDT with red light on acne compared with ALA-PDT with IPL.12 patients were recruited in the randomized, prospective and split-face study. 5% ALA cream were applied on the whole face with 2 hours' incubation before narrow band LED(633 ± 10 nm, 36 ∼ 108J/cm²) on one side of face and IPL(590∼1200 nm, 15∼17J/cm²) on the other side. Three treatment sessions were administered with 2-week interval each time and 8 weeks' follow up. The number of the total acne lesions and inflammatory lesions of the side treated by red light-PDT showed a relatively higher reduction rate that that by IPL-PDT (P < 0.05). Significant PpIX fluorescence decrease was observed only for the group of red light (P < 0.05). Lower pain intensity numeric rating scale values and Investigator's Global Severity Assessment (IGA) grading for erythema of the IPL side were observed (P<0.05).The results suggested that both red light and IPL are effective for ALA-PDT on acne vulgaris. ALA-PDT with red light may achieve better efficacy by more effective photobleaching of protoporphyrin IX (PpIX), whereas IPL may accomplish less adverse reactions and better tolerance.

The Role of Photodynamic Therapy in Acne: An Evidence-Based Review

BACKGROUND

Acne vulgaris is a highly prevalent skin disorder that affects almost all adolescents and can persist into adulthood. Photodynamic therapy (PDT) is an emerging treatment for acne that involves the use of a photosensitizer in combination with a light source and oxygen.

METHODS

We performed a systematic review of the literature and critically evaluated the studies. Sixty-nine clinical trials, four case reports, and two retrospective studies met the inclusion criteria, and seven of the studies were high quality.

RESULTS

The most common photosensitizers used were 5-aminolevulinic acid and methyl aminolevulinate, and both showed similar response. Red light was the most frequently used light source, followed by intense pulsed light, and showed comparable results. Inflammatory and non-inflammatory lesions both responded to treatment, with inflammatory lesions showing greater clearance in most studies. Adverse events associated with PDT for acne were mild and included pain on illumination and post-procedural erythema and edema. PDT has been safely used in higher Fitzpatrick skin types (III-IV), although these patients had a higher risk of transient hyperpigmentation.

CONCLUSION

This review supports PDT as an efficacious treatment for acne and a good adjunctive treatment for mild to severe acne, especially in patients who have not responded to topical therapy and oral antibacterials, and are not great candidates for isotretinoin. Further studies are warranted to evaluate the optimal photosensitizers, light sources, incubation times, and number of treatments for PDT use in acne.

Toward Photopharmacological Antimicrobial Chemotherapy Using Photoswitchable Amidohydrolase Inhibitors

Photopharmacological agents exhibit light-dependent biological activity and may have potential in the development of new antimicrobial agents/modalities. Amidohydrolase enzymes homologous to the well-known human histone deacetylases (HDACs) are present in bacteria, including resistant organisms responsible for a significant number of hospital-acquired infections and deaths. We report photopharmacological inhibitors of these enzymes, using two classes of photoswitches embedded in the inhibitor pharmacophore: azobenzenes and arylazopyrazoles. Although both classes of inhibitor show excellent inhibitory activity (nM IC₅₀ values) of the target enzymes and promising differential activity of the switchable E- and Z-isomeric forms, the arylazopyrazoles exhibit better intrinsic photoswitch performance (more complete switching, longer thermal lifetime of the Z-isomer). We also report protein-ligand crystal structures of the E-isomers of both an azobenzene and an arylazopyrazole inhibitor, bound to bacterial histone deacetylase-like amidohydrolases (HDAHs). These structures not only uncover interactions important for inhibitor binding but also reveal conformational differences between the two photoswitch inhibitor classes. As such, our data may pave the way for the design of improved photopharmacological agents targeting the HDAC superfamily.

Low-Dose Topical 5-Aminolevulinic Acid Photodynamic Therapy in the Treatment of Different Severity of Acne Vulgaris

The objective of this article is to investigate the effectiveness and safety of photodynamic therapy (PDT) with 3.6 % topical aminolevulinic acid (ALA) and a short incubation time with red light in moderate to severe acne. One hundred and thirty-six patients with moderate to severe acne were treated with 3.6 % topical ALA-PDT for three sessions with an interval of 2 weeks. Patients were evaluated for efficacy and safety on week 2, 4, 6, 8, and 12 after the initial treatment. Most patients showed apparent clearance of acne lesions at the treated site after three sessions. The effective treatment rates were increased after the multiple therapies. The clinical outcomes are the best at 4 weeks after the final treatment. The total effectiveness rate and cure rate of the low-dose ALA-PDT procedure is 92.65 and 47.06 %, respectively. Thirty-one patients and nineteen patients showed apparent exacerbation of acne lesions before the 2nd and 3rd treatment, respectively, but all of them showed good or excellent improvement after a three-course treatment. A few patients showed mild relapse including papules and comedos at 8 weeks after the final treatment. No significant differences are found in the effects of different acne severity and different genders. Adverse reactions are mild and transient. A 3.6 % topical ALA-PDT with a short time incubation with red light is a simple and an effective treatment option for moderate to severe acne with mild side effects in Chinese people.

Photodynamic Therapy and Skin Appendage Disorders: A Review

Photodynamic therapy (PDT) is a noninvasive treatment that utilizes light treatment along with application of a photosensitizing agent. In dermatology, PDT is commonly used and approved for the treatment of oncological conditions such as actinic keratosis, Bowen disease and superficial basal cell carcinoma. In the last 2 decades however, PDT has also been used for the treatment of several nonneoplastic dermatological diseases. The present review summarizes published data on PDT application in skin appendage disorders. Our literature review shows that: (a) PDT may be a suitable treatment for acne, folliculitis decalvans, hidradenitis suppurativa, nail diseases, and sebaceous hyperplasia; (b) there is a lack of agreement on PDT features (type, concentrations and incubation period of used substances, number and frequency of PDT sessions, optimal parameters of light sources, and patient characteristics [e.g., failure to previous treatments, disease severity, body surface area involved, etc.] which should guide PDT use in these diseases);

Photoantimicrobials-are we afraid of the light?

Although conventional antimicrobial drugs have been viewed as miraculous cure-alls for the past 80 years, increasing antimicrobial drug resistance requires a major and rapid intervention. However, the development of novel but still conventional systemic antimicrobial agents, having only a single mode or site of action, will not alleviate the situation because it is probably only a matter of time until any such agents will also become ineffective. To continue to produce new agents based on this notion is unacceptable, and there is an increasing need for alternative approaches to the problem. By contrast, light-activated molecules called photoantimicrobials act locally via the in-situ production of highly reactive oxygen species, which simultaneously attack various biomolecular sites in the pathogenic target and therefore offer both multiple and variable sites of action. This non-specificity at the target circumvents conventional mechanisms of resistance and inhibits the development of resistance to the agents themselves. Photoantimicrobial therapy is safe and easy to implement and, unlike conventional agents, the activity spectrum of photoantimicrobials covers bacteria, fungi, viruses, and protozoa. However, clinical trials of these new, truly broad-spectrum, and minimally toxic agents have been few, and the funding for research and development is almost non-existent. Photoantimicrobials constitute one of the few ways forward through the morass of drug-resistant infectious disease and should be fully explored. In this Personal View, we raise awareness of the novel photoantimicrobial technologies that offer a viable alternative to conventional drugs in many relevant application fields, and could thus slow the pace of resistance development.

N-terminal engineering of glutamyl-tRNA reductase with positive charge arginine to increase 5-aminolevulinic acid biosynthesis

Five-Aminolevulinic acid (ALA), the universal precursor of all tetrapyrroles, has various applications in medicine and agriculture industries. Glutamyl-tRNA reductase (GluTR) as the first key enzyme of C5 pathway is feedback regulated by heme, and its N-terminus plays a critical role on its stability control. Here, the GluTR N-terminus was engineered by inserting different numbers of positively charged lysine and arginine residues. The results confirmed that insertion of lysine or arginine residues (especially one arginine residue) behind Thr2 significantly increased the stability of GluTR. By co-expression of the GluTR variant R1 and the glutamate-1-semialdehyde aminotransferase, ALA production was improved 1.76-fold to 1220 mg/L. The GluTR variant R1 constructed here could be used for engineering the C5 pathway to enhance ALA and other products.

Light therapies for acne

BACKGROUND

Acne vulgaris is a very common skin problem that presents with blackheads, whiteheads, and inflamed spots. It frequently results in physical scarring and may cause psychological distress. The use of oral and topical treatments can be limited in some people due to ineffectiveness, inconvenience, poor tolerability or side-effects. Some studies have suggested promising results for light therapies.

OBJECTIVES

To explore the effects of light treatment of different wavelengths for acne.

SEARCH METHODS

We searched the following databases up to September 2015: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase and LILACS. We searched ISI Web of Science and Dissertation Abstracts International (from inception). We also searched five trials registers, and grey literature sources. We checked the reference lists of studies and reviews and consulted study authors and other experts in the field to identify further references to relevant randomised controlled trials (RCTs). We updated these searches in July 2016 but these results have not yet been incorporated into the review.

SELECTION CRITERIA

We included RCTs of light for treatment of acne vulgaris, regardless of language or publication status.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 71 studies, randomising a total of 4211 participants.Most studies were small (median 31 participants) and included participants with mild to moderate acne of both sexes and with a mean age of 20 to 30 years. Light interventions differed greatly in wavelength, dose, active substances used in photodynamic therapy (PDT), and comparator interventions (most commonly no treatment, placebo, another light intervention, or various topical treatments). Numbers of light sessions varied from one to 112 (most commonly two to four). Frequency of application varied from twice daily to once monthly.Selection and performance bias were unclear in the majority of studies. Detection bias was unclear for participant-assessed outcomes and low for investigator-assessed outcomes in the majority of studies. Attrition and reporting bias were low in over half of the studies and unclear or high in the rest. Two thirds of studies were industry-sponsored; study authors either reported conflict of interest, or such information was not declared, so we judged the risk of bias as unclear.Comparisons of most interventions for our first primary outcome 'Participant's global assessment of improvement' were not possible due to the variation in the interventions and the way the studies' outcomes were measured. We did not combine the effect estimates but rated the quality of the evidence as very low for the comparison of light therapies, including PDT to placebo, no treatment, topical treatment or other comparators for this outcome. One study which included 266 participants with moderate to severe acne showed little or no difference in effectiveness for this outcome between 20% aminolevulinic acid (ALA)-PDT (activated by blue light) versus vehicle plus blue light (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.72 to 1.04, low-quality evidence). A study (n = 180) of a comparison of ALA-PDT (activated by red light) concentrations showed 20% ALA was no more effective than 15% (RR 1.05, 95% CI 0.96 to 1.15) but better than 10% ALA (RR 1.22, 95% CI 1.05 to 1.42) and 5% ALA (RR 1.47, 95% CI 1.19 to 1.81). The number needed to treat for an additional beneficial outcome (NNTB) was 6 (95% CI 3 to 19) and 4 (95% CI 2 to 6) for the comparison of 20% ALA with 10% and 5% ALA, respectively.For our second primary outcome 'Investigator-assessed changes in lesion counts', we combined three RCTs, with 360 participants with moderate to severe acne and found methyl aminolevulinate (MAL) PDT (activated by red light) was no different to placebo cream plus red light with regard to change in inflamed lesions (ILs) (mean difference (MD) -2.85, 95% CI -7.51 to 1.81), percentage change in ILs (MD -10.09, 95% CI -20.25 to 0.06), change in non-inflamed lesions (NILs) (MD -2.01, 95% CI -7.07 to 3.05), or in percentage change in NILs (MD -8.09, 95% CI -21.51 to 5.32). We assessed the evidence as moderate quality for these outcomes meaning that there is little or no clinical difference between these two interventions for lesion counts.Studies comparing the effects of other interventions were inconsistent or had small samples and high risk of bias. We performed only narrative synthesis for the results of the remaining trials, due to great variation in many aspects of the studies, poor reporting, and failure to obtain necessary data. Several studies compared yellow light to placebo or no treatment, infrared light to no treatment, gold microparticle suspension to vehicle, and clindamycin/benzoyl peroxide combined with pulsed dye laser to clindamycin/benzoyl peroxide alone. There were also several other studies comparing MAL-PDT to light-only treatment, to adapalene and in combination with long-pulsed dye laser to long-pulsed dye laser alone. None of these showed any clinically significant effects.Our third primary outcome was 'Investigator-assessed severe adverse effects'. Most studies reported adverse effects, but not adequately with scarring reported as absent, and blistering reported only in studies on intense pulsed light, infrared light and photodynamic therapies. We rated the quality of the evidence as very low, meaning we were uncertain of the adverse effects of the light therapies.Although our primary endpoint was long-term outcomes, less than half of the studies performed assessments later than eight weeks after final treatment. Only a few studies assessed outcomes at more than three months after final treatment, and longer-term assessments are mostly not covered in this review.

AUTHORS' CONCLUSIONS

High-quality evidence on the use of light therapies for people with acne is lacking. There is low certainty of the usefulness of MAL-PDT (red light) or ALA-PDT (blue light) as standard therapies for people with moderate to severe acne.Carefully planned studies, using standardised outcome measures, comparing the effectiveness of common acne treatments with light therapies would be welcomed, together with adherence to the Consolidated Standards of Reporting Trials (CONSORT) guidelines.

In situ production of ROS in the skin by photodynamic therapy as a powerful tool in clinical dermatology

Photodynamic therapy (PDT) is a clinical modality of photochemotherapy based on the accumulation of a photosensitizer in target cells and subsequent irradiation of the tissue with light of adequate wavelength promoting reactive oxygen species (ROS) formation and cell death. PDT is used in several medical specialties as an organ-specific therapy for different entities. In this review we focus on the current dermatological procedure of PDT. In the most widely used PDT protocol in dermatology, ROS production occurs by accumulation of the endogenous photosensitizer protoporphyrin IX after treatment with the metabolic precursors 5-methylaminolevulinic acid (MAL) or 5-aminolevulinic acid (ALA). To date, current approved dermatological indications of PDT include actinic keratoses (AK), basal cell carcinoma (BCC) and in situ squamous cell carcinoma (SCC) also known as Bowen disease (BD). With regards to AKs, PDT can also treat the cancerization field carrying an oncogenic risk. In addition, an increasing number of pathologies, such as other skin cancers, infectious, inflammatory or pilosebaceous diseases are being considered as potentially treatable entities with PDT. Besides the known therapeutic properties of PDT, there is a modality used for skin rejuvenation and aesthetic purposes defined as photodynamic photorejuvenation. This technique enables the remodelling of collagen, which in turn prevents and treats photoaging stygmata. Finally we explore a new potential treatment field for PDT determined by the activation of follicular bulge stem cells caused by in situ ROS formation.

Photodynamic therapy with methyl aminolaevulinate 80 mg g(-1) for severe facial acne vulgaris: a randomized vehicle-controlled study

BACKGROUND

Severe acne vulgaris has limited therapeutic options.

OBJECTIVES

To evaluate photodynamic therapy (PDT) using topical methyl aminolaevulinate (MAL, 80 mg g(-1) ) as the photosensitizer in severe facial acne.

METHODS

A double-blind, randomized, vehicle-controlled multicentre trial in 153 patients (aged 12-35 years) with severe facial acne [Investigator's Global Assessment (IGA) score 4; 25-75 inflammatory lesions with ≤ 3 nodules; 20-100 noninflammatory lesions]. Treatment (four treatments 2 weeks apart) involved incubation with MAL (n = 100) or vehicle cream (n = 53) for 1·5 h under occlusion, then illumination (635-nm red light, total dose 37 J cm(-2) ). IGA assessment and standardized lesion counts were performed before each treatment and 12 weeks after the first treatment. Treatment success was defined as improvement from baseline in IGA by ≥ 2 grades at 12 weeks. Safety assessments were for pain (10-cm visual analogue scale, immediately after illumination), erythema (four-point rating scale) and adverse events.

RESULTS

At 12 weeks, PDT using MAL 80 mg g(-1) reduced inflammatory lesions vs. vehicle PDT (mean change -15·6 vs. -7·8, P = 0·006; mean percentage change -37·3% vs. -16·2%, P = 0·003). However, noninflammatory lesions did not decrease significantly (mean change -11·8 vs. -10·7, P = 0·85; mean percentage change -28·6% vs. -24·9%, P = 0·72). Treatment success rates were greater with MAL-PDT 80 mg g(-1) (44% vs. 26%, P = 0·013). Pain was low and manageable by briefly pausing illumination. There was similar pain or erythema with successive treatments.

CONCLUSIONS

PDT using topical MAL 80 mg g(-1) and red light may offer promise for severe acne vulgaris.

The long-term effect of 1550 nm erbium:glass fractional laser in acne vulgaris

We evaluated the short-term and long-term effects of the 1550 nm erbium:glass (Er:glass) fractional laser in the treatment of facial acne vulgaris. Forty-five (9 male and 36 female) acne patients were treated 4 times at 4-week intervals with the following parameters: 169 spot density and 15-30 mJ/cm(2) fluence. There was no control group. The laser spots were adjustable (maximum overlap: 20%) according to the treatment area, and delivered in rows in order to cover all the face. Clinical photographs were taken. The IGA scores and lesion counts were performed for each treatment. Their current state was obtained by phone call follow-up to determine the long-term effect and photographs were offered by themselves or taken in hospital. After four treatments, all patients had an obvious reduction of lesion counts and IGA score and the peak lesion counts decreased to 67.7% after the initial four treatment sessions. For long-term effect, 8 patients lost follow-up, hence 37 patients were followed-up. 8 patients were 2-year follow up, 27 at the 1-year follow-up, and all patients at the half-year follow-up. The mean percent reduction was 72% at the half-year follow-up, 79 at the 1-year follow-up and 75% at the 2-year follow-up. Side effects and complications were limited to transient erythema and edema, and few patients suffered from transient acne flare-ups and sensitivity. All patients responded that their skin was less prone to oiliness. In conclusion, acne can be successfully treated by 1550 nm Er:glass fractional laser, with few side effects and prolonged acne clearing.

Daylight photodynamic therapy with 1.5% 3-butenyl 5-aminolevulinate gel as a convenient, effective and safe therapy in acne treatment: A double-blind randomized controlled trial

While daylight photodynamic therapy (PDT) is a simpler and more tolerable treatment procedure for both clinicians and patients, it has never been applied for acne treatment. In this study, we evaluated efficacy, safety and histological changes of facial acne after application of the novel variant of 5-aminolevulinate (ALA)-ester, 1.5% 3-butenyl ALA-bu gel, using daylight only as the potential visible light source. Forty-six acne patients were randomly assigned to either ALA-bu or vehicle application group in a double-blind fashion. Both groups applied the allocated gel to facial acne lesions every other day for 12 weeks. At the final 12 week, both inflammatory and non-inflammatory acne lesions had decreased significantly by 58.0% and 34.1% in the ALA-bu group, respectively. Only a few patients expressed mild adverse effects. In the histopathological analysis, attenuated inflammatory cell infiltrations were observed and immunostaining intensities for interleukin-8, interleukin-1β, matrix metalloproteinase-9 and phosphorylated nuclear factor-κB were reduced concomitantly. Changes of their mRNA expression demonstrated comparable patterns. In conclusion, this ambulatory PDT was effective, very well tolerated and convenient for treating inflammatory acne lesions. Experimental results correlated well with clinical results. This novel regimen would provide a viable option for acne therapy.

Dual Propionibacterium acnes therapy using skin penetration-enhanced liposomes loaded with a photosensitizer and an antibiotic

Various antibiotics and photosensitizers are used for Propionibacterium acnes therapy. However, the success rate of therapy is limited because of antibiotic resistance, side-effects of photodynamic therapy using photosensitizer and the low skin-penetration efficiency of antibiotics and photosensitizers. In this study, to enhance the skin penetration efficiency, maintain their photodynamic activity and induce dual antibacterial therapeutic effects, we prepare erythromycin and branched polyethyleneimin-hematoporphyrin (bPEI-HPP) conjugates were loaded into liposomes (cationic photosensitizer-erythromycin loaded liposomes, CP-L (bPEI-HPP 10 mg; CP-L 1 and 20 mg; CP-L 2)). The tissue penetration efficiency of CP-Ls was determined by the Franz cell diffusion system and fluorescence microscopy. The penetration efficiency of CP-Ls is greater than that of bPEI-HPP, unloaded cationic photosensitizer and free HPP because CP-Ls comprised phospholipids that are similar to the cell membrane lipid composition. For in vitro antibacterial effects, Propionibacterium acnes (P. acnes) were used. The loss of viability rate of P. acnes by CP-L 2 (95%) from the colony forming unit (CFU) assay, was 2.4-fold higher than erythromycin-loaded liposomes (39%) and 1.9-fold higher than bPEI-HPP-loaded liposomes (50%). Therefore, we suggest that polycationic photosensitizer and antibiotic-loaded liposomes have potential applications in clinical photodynamic anti-bacterial therapy.

Clinical efficacy of 5-aminolevulinic acid photodynamic therapy in the treatment of moderate to severe facial acne vulgaris

Acne vulgaris is considered as a therapeutic challenge in terms of managing ongoing symptoms and preventing scar formation. Although there are many available treatments for alleviating acne, therapies for resistant or moderate-to-severe forms have been limited to systemic agents that are accompanied by potentially severe side-effects. While, aminolevulinic acid (ALA) photodynamic therapy (PDT) has increasingly been used as a simple and safe therapeutic option of acne vulgaris, the clinical efficacy requires confirmation in further studies. The aim of this study was to investigate the efficacy and safety of 5-ALA-PDT in the treatment of moderate-to-severe facial acne vulgaris. A total of 50 patients with moderate-to-severe facial acne were enrolled in the study and randomly divided equally into a therapy group and a control group. In the therapy group, the patients were treated with 5% 5-ALA for 1.5 h, followed by three 20-min doses of infrared radiation once a week; in the control group, the patients were treated with three 20 min doses of infrared radiation without 5-ALA once a week. Both treatments lasted for 3 weeks. The clinical efficacy was determined by evaluating acne lesion counts at weeks 0, 2, 4 and 6. Total efficacy rate (TER) was the primary endpoint of the study, and was defined as the proportion of the patients whose treatment effectiveness evaluation was cured (≥90% of skin lesions improved) and excellent (60-89% improvement). Adverse effects were recorded throughout the study. The study was completed by 24 patients in the therapy group and 23 patients in the control group. The numbers of acne lesions significantly decreased. The TER of the therapy group was significantly higher than that of the control group at weeks 4 and 6. Adverse effects were observed in 12 patients of the therapy group and 2 patients of the control group. In the therapy group the most common adverse effect was a burning sensation (n=7), followed by transient hyperpigmentation (n=3) and acute acneform lesions (n=2), while in control group, the 2 patients experienced flushing and dryness. The adverse effects were all cured by a symptomatic approach prior to the end of the study. 5-ALA-PDT combined with infrared radiation is an effective and safe therapy for moderate-to-severe facial acne.

A new LED device used for photodynamic therapy in treatment of moderate to severe acne vulgaris

OBJECTIVE

This study investigated the efficacy and safety of a newly designed LED device used in photodiagnosis and photodynamic therapy of moderate to severe acne vulgaris in Chinese patients.

METHODS

Forty-six patients with moderate to severe facial acne showing high degrees of fluorescence by ultraviolet light examination were illuminated during ALA-PDT with two wavelengths of light (543-548 nm, and 630±6 nm, respectively) after 2 h of incubation with ALA. Each patient received treatment once every 30 days for two or three sessions. Two independent investigators assigned an acne severity score at baseline, one week after each treatment, as well as 4, 8, and 12 weeks after the completion of treatment. Adverse effects were recorded during and after each treatment. All patients rated their satisfaction with the results of treatment at a 12-week follow up visit.

RESULTS

The ALA-PDL treatment regimen showed an overall effectiveness rate of 89.13% (41/46 patients). Some degree of clinical efficacy was seen in 71.42%, 86.67%, and 95.83% of patients with grades IV, V, and VI acne, respectively, and the rate of clinical effectiveness increased with increasing acne severity. When compared with baseline scores, significant reductions in acne scores were obtained at 8, and 12 weeks after completion of treatment. Maximum efficacy was shown at the 12 week follow up. No severe adverse events were observed.

CONCLUSION

ALA-PDT administered with the newly designed LED device was an effective treatment for moderate to severe acne vulgaris, and side effects were mild and reversible.