Protoporphyrin IX formation and photobleaching in different layers of normal human skin: Methyl- and hexylaminolevulinate and different light sources

RANDOMIZED CONTROLLED TRIAL FOR EVALUATION OF EFFICACY AND PAIN DURING PHOTODYNAMIC THERAPY FOR ACTINIC KERATOSIS OF FACE AND SCALP COMPARING TWO IRRADIATION PROTOCOLS

BACKGROUND

Pain is a frequent adverse event during photodynamic therapy, which can limit treatment acceptance. This study aimed to evaluate the efficacy and pain during photodynamic therapy with two irradiation protocols in patients with actinic keratosis on the face and scalp.

METHODS

In this intra-patient randomized controlled trial, participants were randomly allocated to receive photodynamic therapy with methyl aminolevulinate and red light on the right or left side with protocol 1 (irradiation device in contact with the skin) and protocol 2 (device 3 cm away from the skin). There was a 15-day interval between the protocols. The primary outcome was the frequency of mean intensity of moderate or severe pain during photodynamic therapy. Secondary outcomes were actinic keratosis clearance rate, protoporphyrin IX consumption, participant preference, skin appearance, and adverse events.

RESULTS

Forty-one participants were included, yielding 47 and 50 randomized sites for protocols 1 and 2. There was no difference in the frequency of moderate and severe pain, with a relative risk of 1.09 (95% CI 0.70-1.70), p>0.05. An actinic keratosis count reduction >60% was observed in both protocols (p<0.01), with no difference between them. There was no difference in protoporphyrin IX consumption. Most treated sites were of good to excellent quality. There was a greater patient preference for protocol 2 (p<0.01).

CONCLUSIONS

The pain intensity was similar between the protocols, and the protocols were equally effective for actinic keratosis clearance, protoporphyrin IX consumption, and improvement in the quality of the treated areas. Both protocols can be considered safe.

How Much Protoporphyrin IX Must Be Activated to Obtain Full Efficacy of Methyl Aminolevulinate Photodynamic Therapy? Implication for Treatment Modifications

Photodynamic therapy (PDT) with methyl aminolevulinate (MAL) is a popular treatment for actinic keratoses (AK), and several PDT treatment modalities with similar cure rates are in use. The effect relies on the activation of protoporphyrin IX (PpIX) in premalignant cells. This study aimed to measure PpIX during each treatment modality to determine the minimal PpIX activation and shortest exposure time for optimal cure rate. In four different treatment modalities, we established the PpIX formation up to three hours after MAL application without illumination and measured the speed of PpIX photoactivation during 9 min of red light (37 J/cm²). The level of PpIX three hours after MAL application was set to 100 PpIX units. In comparison, 85 PpIX units were formed during daylight PDT, 57 PpIX units during pulse PDT, and 52 PpIX units without any curettage prior to MAL. The activation of 50 PpIX units should, therefore, be enough to obtain a full effect on AK. Further, red light illumination may be shortened from 9 min to 1–2 min. The results indicate that PDT can be performed successfully with half the illumination time used in daylight PDT today and with one fourth of the illumination time used in classical PDT.

Update Dermatologische Lasertherapie II – Weiterentwicklung der photodynamischen Therapie durch Laser‐assistierte transkutane Applikation von Topika

Die technische Fortentwicklung der jüngeren Vergangenheit bietet dem Dermatologen Zugriff auf neue Laser, Strahlquellen und Behandlungskonzepte. Seit langem eingeführte Wellenlängen zur Ablation sind nunmehr fraktioniert applizierend verfügbar und stehen nunmehr für eine wirksamere und effizientere Behandlung von zahlreichen Hautveränderungen zur Verfügung. Das gezielte Einbringung von Topika (laser assisted drug delivery; LADD) ist das wichtigste Beispiel. Die LADD erfordert eine spezifische Weiterbildung, um sicher und wirksam zur Therapie (prä-)maligner nichtmelanozytärer Neoplasien der Haut wie der Feldkanzerisierung in Form der Laser-assistierten photodynamischen Therapie angewandt werden zu können. Bisher verfügbare Daten weisen auf eine höhere Effektivität im Vergleich zu konventionell verwendeten Topika hin, wobei anhaltend über Weiterentwicklungen berichtet wird. Unter anderem wurde die Kombination mit Tageslicht oder alternativen tageslichtähnlichen Strahlquellen bekannt. Dieses Update basiert wie zitiert gekürzt und aktualisiert auf "Paasch, U. 2019. Laser-assistierte photodynamische Therapie. p. 226-239. In G. Kautz (ed.) Energie für die Haut. Springer Nature, Springer Nature.".

Update on dermatologic laser therapy II - advances in photodynamic therapy using laser-assisted drug delivery

Technical advances in recent years have led to the development of new dermatologic laser systems, light sources, and treatment concepts. With the introduction of ablative fractional lasers (using common wavelengths) in the field of dermatology, it is now possible to more effectively and efficiently treat a variety of skin disorders. One important example of these advances is laser-assisted drug delivery (LADD). A type of LADD, laser-assisted photodynamic therapy has been successfully employed in the treatment of non-melanoma skin cancer including field cancerization. This treatment concept has been continually modified and today includes the use of daylight as well as artificial daylight systems. This update is based as cited, shortened and updated according to "Paasch,U. 2019. Laser-assistierte photodynamische Therapie. p. 226-239. In G.Kautz (ed.) Energie für die Haut. Springer Nature, Springer Nature".

Thermo-Mechanical Fractional Injury Enhances Skin Surface- and Epidermis- Protoporphyrin IX Fluorescence: Comparison of 5-Aminolevulinic Acid in Cream and Gel Vehicles

BACKGROUND AND OBJECTIVES

Thermo-mechanical fractional injury (TMFI) impacts the skin barrier and may increase cutaneous drug uptake. This study investigated the potential of TMFI in combination with 5-aminolevulinic acid (ALA) cream and gel formulations to enhance Protoporphyrin IX (PpIX) fluorescence at the skin surface and in the skin.

STUDY DESIGN/MATERIALS AND METHODS

In healthy volunteers (n = 12) a total of 144 test areas were demarcated on the upper back. Test areas were randomized to (i) TMFI (6 milliseconds, 400 µm at a single pass) or no pretreatment and (ii) 20% ALA in cream or gel formulations. Skin surface PpIX fluorescence was quantified by PpIX fluorescence photography and photometry in 30-minute intervals until 3 hours. PpIX fluorescence microscopy quantified separate PpIX fluorescence in the epidermis, and in superficial-, mid-, and deep- dermis from punch biopsies sampled after 3 hours of ALA incubation. Local skin reactions (LSR) and pain intensities (numerical rating scale 0-10) were evaluated immediately, at 3 hours and 14 days after the intervention.

RESULTS

TMFI exposure before photosensitizer application significantly increased skin surface PpIX fluorescence, both for ALA cream (TMFI-ALA-cream 7848 arbitrary units [AU] vs. ALA-cream 5441 AU, 3 hours, P < 0.001) and ALA gel (TMFI + ALA-gel 4591 AU vs. ALA-gel 3723 AU, 3 hours, P < 0.001). The TMFI-mediated increase in PpIX fluorescence was similar for ALA-cream and -gel formulations (P = 0.470) at the skin surface. In the epidermis, PpIX fluorescence intensities increased from combination treatment with TMFI and ALA-cream (TMFI + ALA-cream 421 AU vs. ALA-cream 293 AU, P = 0.034) but not from combination with TMFI and ALA-gel (TMI + ALA-gel 264 AU vs. ALA-gel 261 AU, P = 0.791). Dermal fluorescence intensities (superficial-, mid-, or deep dermis) were unaffected by TMFI pretreatment in both ALA-cream and ALA-gel exposed skin (P = 0.339). ALA-cream generally induced higher PpIX fluorescence intensities than ALA-gel (skin surface P < 0.001 and epidermis P < 0.03). TMFI induced low pain intensities (median 3) and mild LSR that were resolved at 14 days follow-up.

CONCLUSION

Given the present study design, TMFI, in combination with the standardized application of 20% ALA cream and gel formulations, significantly enhanced skin surface PpIX fluorescence compared to no pretreatment. Additionally, TMFI increased epidermal PpIX fluorescence combined with 20% ALA cream vehicle. Thus, TMFI pretreatment and formulation characteristics exert influence on PpIX fluorescence intensities in normal skin. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Hexyl aminolevulinate, 5-aminolevulinic acid nanoemulsion and methyl aminolevulinate in photodynamic therapy of non-aggressive basal cell carcinomas: A non-sponsored, randomized, prospective and double-blinded trial

BACKGROUND

In the photodynamic therapy (PDT) of non-aggressive basal cell carcinomas (BCCs), 5-aminolevulinic acid nanoemulsion (BF-200ALA) has shown non-inferior efficacy when compared with methyl aminolevulinate (MAL), a widely used photosensitizer. Hexyl aminolevulinate (HAL) is an interesting alternative photosensitizer. To our knowledge, this is the first study using HAL-PDT in the treatment of BCCs.

OBJECTIVES

To compare the histological clearance, tolerability (pain and post-treatment reaction) and cosmetic outcome of MAL, BF-200 ALA and low-concentration HAL in the PDT of non-aggressive BCCs.

METHODS

Ninety-eight histologically verified non-aggressive BCCs met the inclusion criteria, and 54 patients with 95 lesions completed the study. The lesions were randomized to receive LED-PDT in two repeated treatments with MAL, BF-200 ALA or HAL. Efficacy was assessed both clinically and confirmed histologically at three months by blinded observers. Furthermore, cosmetic outcome, pain, post-treatment reactions fluorescence and photobleaching were evaluated.

RESULTS

According to intention-to-treat analyses, the histologically confirmed lesion clearance was 93.8% (95% confidence interval [CI] = 79.9-98.3) for MAL, 90.9% (95% CI = 76.4-96.9) for BF-200 ALA and 87.9% (95% CI = 72.7-95.2) for HAL, with no differences between the arms (P = 0.84). There were no differences between the arms as regards pain, post-treatment reactions or cosmetic outcome.

CONCLUSIONS

Photodynamic therapy with low-concentration HAL and BF-200 ALA has a similar efficacy, tolerability and cosmetic outcome compared to MAL. HAL is an interesting new option in dermatological PDT, since good efficacy is achieved with a low concentration.

Skin surface Protoporphyrin IX fluorescence is associated with epidermal but not dermal fluorescence intensities

BACKGROUND

Photodynamic therapy with Protoporphyrin IX (PpIX) is well-established for keratinocyte dysplasia. PpIX fluorescence can be quantified at the skin surface and within skin layers, but their relation is previously undescribed. The study objective was to assess the relation between skin surface PpIX fluorescence and PpIX fluorescence in epidermis and dermis.

METHODS

Normal buttocks skin was tape-stripped and incubated with 20 % methyl aminolevulinate cream and 20 % hexyl aminolevulinate cream under occlusion. After 3 h, skin surface PpIX fluorescence photographs were captured and 4 mm punch biopsies sampled. PpIX fluorescence microscopy was measured in regions of interest (ROI) in epidermis and superficial dermis. All PpIX fluorescence intensities were calculated in arbitrary units (AU).

RESULTS

Skin surface PpIX fluorescence intensity expressed a positive, linear relation to ROI-epidermis PpIX fluorescence (HAL- and MAL-incubated skin, p < 0.001, r² = 0.60), but not to PpIX fluorescence intensities in ROI-superficial dermis (p = 0.112). PpIX fluorescence microscopy identified higher fluorescence intensities in ROI-epidermis (median 92 AU) compared to lower fluorescence intensities in ROI-superficial dermis (median 37 AU) (p < 0.001). HAL reached higher median PpIX fluorescence intensities than MAL when measured by skin surface photographs (10230 vs. 5630 AU, p < 0.001), andbyfluorescence microscopy in ROI-epidermis (107 vs. 52.5 AU, p < 0.001) or ROI-superficial dermis (40 vs. 30.5 AU, p = 0.04).

CONCLUSION

The positive linear relation between skin surface PpIX fluorescence photographs and epidermal PpIX fluorescence microscopy indicates that skin surface PpIX fluorescence predominantly derives from epidermis.

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.

Update of Ablative Fractionated Lasers to Enhance Cutaneous Topical Drug Delivery

Ablative fractional lasers (AFXL) enhance uptake of therapeutics and this newly emerging field is called laser-assisted drug delivery (LAD). This new science has emerged over the past decade and is finding its way into clinical practice. LAD is poised to change how medicine delivers drugs. Topical and systemic application of pharmaceutical agents for therapeutic effect is an integral part of medicine. With topical therapy, the stratum corneum barrier of the skin impairs the ability of drugs to enter the body. The purpose of LAD is to alter the stratum corneum, epidermis, and dermis to facilitate increased penetration of a drug, device, or cell to its respected target. AFXL represents an innovative, non-invasive strategy to overcome the epidermal barrier. LAD employs three steps: (1) breakdown of the skin barrier with a laser, (2) optional use a laser for a therapeutic effect, (3) delivery of the medicine through laser channels to further enhance the therapeutic effect. The advantages of using lasers for drug delivery include the ease of accessibility, the non-invasive aspect, and its effectiveness. By changing the laser settings, one may use LAD to have a drug remain locally within the skin or to have systemic delivery. Many drugs are not intended for use in the dermis and so it has yet to be determined which drugs are appropriate for this technique. It appears this developing technology has the ability to be a new delivery system for both localized and systemic delivery of drugs, cells, and other molecules. With responsible development AFXL-assisted drug delivery may become a new important part of medicine.

Photodynamic Therapy: A Clinical Consensus Guide

BACKGROUND

The American Society of Dermatologic Surgery (ASDS) periodically develops consensus documents for its members concerning various aspects of dermatologic surgery. Advances in photodynamic therapy (PDT) have been many and PDT use has been established in a variety of skin conditions.

OBJECTIVE

The ASDS board of directors proposed a committee of experts in the field to develop consensus documents on different treatments. An expert panel reviewed the literature on PDT and discussed the findings. The consensus was reached with evidence-based recommendations on different clinical applications for PDT.

PATIENTS AND METHODS

This consensus document includes discussions regarding PDT, including different photosensitizers and various light source activators, historical perspective, mechanism of action, various therapeutic indications and expected outcomes, pre- and post-care, and management of adverse outcomes.

RESULTS

Photodynamic therapy is highly effective for pre-cancerous lesions, superficial nonmelanoma skin cancers, inflammatory acne vulgaris and other conditions. New protocols including laser mediated PDT significantly improve results for several indications.

CONCLUSION

The ASDS consensus document on PDT will be helpful for educating members on safe and effective PDT for a variety of indications.

Multiple sequential light and laser sources to activate aminolevulinic acid for rosacea

BACKGROUND AND AIMS

The use of multiple, sequential light and laser sources for topical ALA activation in photodynamic therapy (PDT) of rosacea has been largely absent from the literature. The aim of this study was to evaluate ALA-PDT for rosacea using blue light sequentially with red light, pulsed-dye laser (PDL), and/or intense pulsed light (IPL).

PATIENTS/METHODS

Thirty patients (39 treatments) were enrolled in this retrospective, single-center study. Treatment groups included blue light + PDL, blue light + IPL, blue light + PDL + IPL, or blue light + red light + PDL + IPL. Patient-reported outcome measures (incidence of adverse events, improvement in rosacea, and improvement in overall skin quality) were obtained via a telephone questionnaire and graded on a 4-point scale.

RESULTS

There was no statistically significant difference in patient-reported rosacea or overall skin quality improvement. Apart from decreased peeling following blue light + IPL compared to blue light + PDL (P = 0.041) and blue light + IPL + PDL (P = 0.005), there were no other statistically significant differences in postprocedure adverse events.

CONCLUSIONS

The use of multiple, sequential light and laser sources with ALA-PDT for rosacea, while well tolerated, did not lead to statistically significant improvements in patient-reported efficacy. Although this retrospective study is limited by a small sample size with disparate patient numbers between groups and no physician-evaluated outcome criteria, it does demonstrate that multiple light sources with PDT can be safely used in a single session.

Evidence and conjecture about mechanisms of cutaneous disease in photodermatology

Photosensitivity disorders are caused by a variety of mechanisms. Three common themes are as follows: excess chromophore allowing visible light energy to cause photodynamic damage, reduced DNA repair capacity to UV-induced DNA damage, and enhanced sensitivity to light-induced allergens mediated immunologically. Although the cause of each condition may be known, the precise pathogenesis underlying the photosensitivity has taken longer to understand. By focussing on three clinical disorders under each of these themes, we have explored the following: why erythropoietic protoporphyria differs so markedly from the other cutaneous porphyrias; how a DNA repair defect was eventually revealed to be the underlying cause of the vitamin B3 deficiency disorder of pellagra; an immunological explanation for the over reactivity to photoallergens in chronic actinic dermatitis.

Oncologic photodynamic therapy: clinical strategies that modulate mechanisms of action

Photodynamic therapy (PDT) is an elegant minimally invasive oncologic therapy. The clinical simplicity of photosensitizer (PS) drug application followed by appropriate illumination of target leading to the oxygen dependent tumor ablative Photodynamic Reaction (PDR) has gained this treatment worldwide acceptance. Yet the true potential of clinical PDT has not yet been achieved. This paper will review current mechanisms of action and treatment paradigms with critical commentary on means to potentially improve outcome using readily available clinical tools.