Current status of photodynamic therapy in dermatology

Epigenetically Enhanced PDT Induces Significantly Higher Levels of Multiple Extrinsic Pathway Apoptotic Factors than Standard PDT, Resulting in Greater Extrinsic and Overall Apoptosis of Cutaneous T-cell Lymphoma

Aminolevulinate-based photodynamic therapy (ALA-PDT) selectively eliminates diseased tissues primarily through the induction of intrinsic apoptotic pathway. ALA-PDT is a first-line therapy for actinic keratosis, however, it is less effective for cutaneous T-cell lymphoma (CTCL). We have previously demonstrated that the resistance of CTCL to apoptosis correlates with decreased expression of death receptors such as FAS, and that methotrexate functions as an epigenetic regulator that reestablishes the susceptibility of CTCL to extrinsic pathway apoptosis. We showed previously that MTX augments the effectiveness of PDT by sensitizing cells to apoptosis by induction of apoptotic factors, a process we call "epigenetically enhanced" PDT (ePDT). Here, in CTCL cell lines, leukemic CTCL cells, and normal blood T cells, we analyzed multiple components of the FAS, TRAIL, and TNF families using multispectral imaging of immunostained cytopreparations, a quantitative technique with five-fold greater sensitivity than standard immunocytology. ePDT induced significantly greater FAS, FASL, TRAIL-R1 & -R2, and TNFα levels than standard PDT. This correlated with significantly greater induction of extrinsic pathway apoptosis and/or overall apoptosis in all CTCL samples. There was no appreciable effect on normal T cells. These data set the stage for clinical trials of ePDT as a novel localized treatment of CTCL.

Epigenetically Enhanced Photodynamic Therapy (ePDT) is Superior to Conventional Photodynamic Therapy for Inducing Apoptosis in Cutaneous T-Cell Lymphoma

Conventional photodynamic therapy with aminolevulinate (ALA-PDT) selectively induces apoptosis in diseased cells and is highly effective for treating actinic keratoses. However, similar results are achieved only in a subset of patients with cutaneous T-cell lymphoma (CTCL). Our previous work shows that the apoptotic resistance of CTCL correlates with low expression of death receptors like Fas cell surface death receptor (FAS), and that methotrexate upregulates FAS by inhibiting the methylation of its promoter, acting as an epigenetic derepressor that restores the susceptibility of FAS-low CTCL to caspase-8-mediated apoptosis. Here, we demonstrate that methotrexate increases the response of CTCL to ALA-PDT, a concept we refer to as epigenetically enhanced PDT (ePDT). Multiple CTCL cell lines were subjected to conventional PDT versus ePDT. Apoptotic biomarkers were analyzed in situ with multispectral imaging analysis of immunostained cells, a method that is quantitative and 5× more sensitive than standard immunohistology for antigen detection. Compared to conventional PDT or methotrexate alone, ePDT led to significantly greater cell death in all CTCL cell lines tested by inducing greater activation of caspase-8-mediated extrinsic apoptosis. Upregulation of FAS and/or tumor necrosis factor-related apoptosis-inducing ligand pathway components was observed in different CTCL cell lines. These findings provide a rationale for clinical trials of ePDT for CTCL.

Intralesional therapy for psoriasis

Localized resistant plaques of psoriasis often remain despite highly effective anti-psoriasis treatment. Intralesional therapy is often used to treat various malignant, infectious or inflammatory cutaneous diseases, including psoriasis. Despite the presence of many review articles on the treatment of psoriasis, no articles exist which review the use of intralesional therapy for psoriasis. In this article, we review the published literatures of intralesional therapy for psoriasis. Corticosteroids, methotrexate, cyclosporin, biologics, botulinum toxin type-A, 15-hydroxyeicosatetraenoic acid, and chemotherapy agents such as 5-fluorouracil are discussed. Also, agents which may be used intralesionally and have the potential to treat psoriasis will also be reviewed such as bleomycin, vincristine or vinblastine, mitomycin-C, aminophylline, 5-aminolevulinic acid, rituximab, bevacizumab and pentoxifylline are included.

Photodynamic therapy using a methyl ester of 5-aminolevulinic acid in recurrent Paget's disease of the vulva: a pilot study

OBJECTIVE

In the past, treating vulvar Paget's disease through surgery has resulted in a high recurrence rate of the disease. Photodynamic therapy (PDT) using 5-aminolevulinic acid (5 ALA) is an effective treatment for some conditions such as Bowen's disease, subsets of basal cell carcinomas and vulvar carcinoma. Methyl 5-aminolevulinate (MAL) is an ester of 5 ALA that seems to be more effective and produces fewer side effects than 5 ALA. This paper outlines a pilot study designed to test the feasibility of using MAL-PDT in the treatment of recurrent vulvar Paget's disease.

METHODS

5 MAL-PDT was applied for 3 h and than irradiated with red-light (620 nm) using a total light dose of 37 J/cm2 for a period of 10 min. Patients taking part in the study were treated once every 3 weeks, for a total of three treatments. Vulvar biopsies were obtained before and 1 month after the PDT-treatment.

RESULTS

Seven patients were enrolled in the study. Four cases had a complete clinical response, and this was pathologically confirmed in two of the cases. The cosmetic outcome was acceptable and the treatment was well tolerated. All the patients developed local edema and mild local pain, controlled with non-steroidal antiinflammatory drugs (NSAIDS). One patient experienced severe pain and a mild local phototoxicity reaction.

CONCLUSIONS

MAL-PDT is a feasible treatment and seems to offer a reliable strategy in the control of vulvar Paget's disease and of its symptoms.

Development and characterization of multi-sensory fluence rate probes

Multi-sensory fluence rate probes (MSPs) yield several simultaneous measurements of photodynamic therapy (PDT) treatment light fluence from a single interstitial probe. Fluorescent sensors are embedded at desired positions along the axis of the optical fibre. A single fluorescence emission spectrum is obtained and decomposed using a partial least squares (PLS)-based analysis to yield the fluence at each sensor's location. The responsivity, linearity and possible photodegradation of each fluorophore chosen for the MSPs were evaluated using single-sensor probes. The performance of two- and three-sensor MSPs was evaluated experimentally. Individual fluorescence spectra collected from each sensor on the MSP were used to construct the training set necessary for the PLS-based analysis. The MSPs' responsivity, spatial resolution and accuracy were evaluated relative to a single scattering-tip detector. Three-fluorophore MSPs permitted three simultaneous measurements of the fluence rate gradient in a tissue-like phantom, with an average accuracy of 6.7%. No appreciable photodegradation or cross-talk was observed.

Therapeutic effects of 5-ALA-induced photodynamic therapy in vulvar lichen sclerosus

BACKGROUND

Lichen sclerosus (LS) is a rarely diagnosed, chronic inflammatory skin and mucosal condition. Its therapy is difficult and frequently not satisfactory. The data on photodynamic therapy (PDT) of vulva are promising but scanty. The aim of our study was to evaluate the therapeutic efficacy of photodynamic therapy in genital LS in women.

METHODS

Twenty-four patients with clinical and histopathological diagnosis of lichen sclerosus accompanied with chronic vulvar itching, lasting between 3 months and 11 years, with human papillomavirus (HPV), bacterial and mycotic infections excluded, received three to six PDT cycles (180J, 700mW/cm(2)) in 14 days long intervals. Simultaneously they received no topical corticosteroids. Photodynamic diagnosis (PDD) was conducted prior to therapy and 4 weeks after its completion.

RESULTS

In 17 patients, the itching ceased completely, in 6 women it decreased, in 1 patient the itching continued, none of the patients presented exacerbation of itching. PDD after completion of therapy revealed in 10 patients normal, green fluorescence of vulva and in 14 women pathological, red fluorescence, usually fainter than before PDT.

CONCLUSION

PDT is an effective therapeutic modality for chronic itching in lichen sclerosus.

Erythroplasia of Queyrat treated with topical methyl aminolevulinate photodynamic therapy

An 82-year-old man presented with invasive squamous cell carcinoma of the glans penis arising in erythroplasia of Queyrat. He underwent Mohs' micrographic surgery for the invasive carcinoma. Seven weeks later, the residual erythroplasia of Queyrat was treated using photodynamic therapy. Methyl aminolevulinate cream was applied to the glans of the penis under occlusion for 3 hours and then, after local anaesthesia, irradiated with a 630-nm red-light-emitting diode lamp at a dose of 37 J/cm(2) for 8 min. The patient experienced some mild swelling, redness and pain, which subsided over the following 5 days. Eighteen weeks after photodynamic therapy, there had been no recurrence of the lesion, when the patient died from an unrelated cause.

5-aminolevulinic acid photodynamic therapy: where we have been and where we are going

BACKGROUND

Photodynamic therapy, utilizing the topical administration of 20% 5-aminolevulinic acid, has generated a great deal of interest in the dermatology community over the past several years.

OBJECTIVE

The purpose of this article is to review the history of photodynamic therapy in dermatology and to review recent new advances with this technology that will increase its appeal to all dermatologists.

METHODS

A literature review and results of new clinical trials with regards to photorejuvenation and acne vulgaris treatments with 5-aminolevulinic acid photodynamic therapy are presented.

RESULTS

Short-contact, full-face 5-aminolevulinic acid photodynamic therapy treatments with a variety of lasers and light sources have shown to be successful in treating all facets of photorejuvenation and the associated actinic keratoses as well as disorders of sebaceous glands, including acne vulgaris. The treatments are relatively pain-free, efficacious, and safe. They are also making already available laser/light source therapies work better for acne vulgaris and photorejuvenation.

CONCLUSIONS

The use of 5-aminolevulinic acid photodynamic therapy with short-contact, full-face broad-application therapy is now able to bridge the world of medical and cosmetic dermatologic surgery. This therapy is available for all dermatologists to utilize in the care of their patients.

Irradiance and light dose influence histological localization of photodamage induced by photodynamic therapy with aminolaevulinic acid

BACKGROUND

Photodynamic therapy (PDT) with aminolaevulinic acid (ALA) is used in many countries for the treatment of actinic keratoses.

OBJECTIVES

The objectives of the current study were to evaluate the influence of irradiance and light dose on the localization and extent of photodamage to mouse skin following ALA-PDT.

METHODS

In this study we evaluated the influence of irradiance and light dose on epidermal photodamage following ALA-PDT. Groups of hairless mice received an intraperitoneal injection of ALA followed 2 h later by exposure to 12 J cm(-2), 24 J cm(-2) or 48 J cm(-2) of unfiltered light from a slide projector. For each of these fluences, groups of mice were exposed at the following irradiances: 5 mW cm(-2), 20 mW cm(-2) or 40 mW cm(-2). Skin biopsies were performed 24 h and 72 h later.

RESULTS

Histological localization of photodamage was influenced by irradiance and light dose. At high irradiance and low fluence, PDT photodamaged cells were mostly located in the upper area of the epidermis whereas at lower irradiance and high fluence the complete epidermis was necrotic and often absent 24 h after light exposure. Protoporphyrin IX (PpIX) fluorescence intensity was similar in the upper and lower region of the epidermis 2 h after ALA injection. The decrease in PpIX fluorescence intensity immediately after light exposure was also similar in both regions of the epidermis.

CONCLUSIONS

The localization of photodamage following ALA-PDT is influenced by irradiance and light dose. This phenomenon cannot be explained by differences in PpIX intensity in the epidermis either before or after light exposure.

Lasers in dermatology: four decades of progress

Advances in laser technology have progressed so rapidly during the past decade that successful treatment of many cutaneous concerns and congenital defects, including vascular and pigmented lesions, tattoos, scars, and unwanted hair-can be achieved. The demand for laser surgery has increased substantially by patients and dermatologists alike as a result of the relative ease with which many of these lesions can be removed, combined with a low incidence of adverse postoperative sequelae. Refinements in laser technology and technique have provided patients and practitioners with more therapeutic choices and improved clinical results. In this review, the currently available laser systems with cutaneous applications are outlined, with primary focus placed on recent advancements and modifications in laser technology that have greatly expanded the cutaneous laser surgeon's armamentarium and improved overall treatment efficacy and safety.

Fiber optic probes for biomedical optical spectroscopy

Fiber optic probes are a key element for biomedical spectroscopic sensing. We review the use of fiber optic probes for optical spectroscopy, focusing on applications in turbid media, such as tissue. The design of probes for reflectance, polarized reflectance, fluorescence, and Raman spectroscopy is illustrated. We cover universal design principles as well as technologies for beam deflecting and reshaping.

Photodynamic therapy and topical aminolevulinic acid: an overview

Photodynamic therapy is a non-invasive technique used in the treatment of skin diseases which has various advantages, one being the ability to localize treatment to the area being treated, which is common among most photosensitizers. Aminolevulinic acid is a prodrug that is metabolized intracellularly to form the photosensitizing molecule protoporphyrin IX (PpIX). When PpIX is activated by light, cytotoxic reactive oxygen species and free radicals are generated. This phototoxic effect may cause malignant and non-malignant hyperproliferative tissue to be destroyed, to decrease in size, and to eventually disappear. The application of topical aminolevulinic acid 20% followed by the use of a blue light photodynamic therapy illuminator is indicated in the US for the treatment of non-hyperkeratotic actinic keratoses of the face or scalp. There are data suggesting that aminolevulinic acid/photodynamic therapy may also be beneficial in acne vulgaris, verrucae, psoriasis, mycosis fungoides, and human papillomavirus. This treatment modality has also proven effective in the management of skin cancer such as, Bowen disease and basal cell carcinoma. Further experience in the use of photodynamic therapy will help define its utility in the management of actinic keratosis and other dermatoses.

Systemic photodynamic therapy with aminolevulinic acid induces apoptosis in lesional T lymphocytes of psoriatic plaques

Photodynamic therapy (PDT) is a recently approved treatment modality that involves the sequential administration of a photosensitizer or its precursor and light to generate singlet oxygen for treating diseased tissue. The use of topical aminolevulinic acid (ALA) and blue light for nonhypertrophic actinic keratoses currently represents the only approved dermatologic application for PDT in the U.S.A. ALA is a photosensitizer precursor that is metabolized by cells into protoporphyrin IX (PpIX), which can be subsequently activated by visible light. PDT with topical ALA has been shown to improve psoriasis, but post-treatment hyperpigmentation as well as inconsistent clinical responses despite repeated PDT sessions have limited the development of this treatment approach for psoriasis. Furthermore the use of topical PDT photosensitizers becomes somewhat impractical for treating larger body surface areas in patients with extensive psoriasis. We have recently shown that oral administration of ALA induces preferential accumulation of PpIX in psoriatic plaques. The objectives of this study were to evaluate the effects of PDT with blue light on psoriatic plaques after systemic ALA administration as well as to determine whether systemic ALA-PDT induces apoptosis in lesional T lymphocytes. It has been suggested that induction of apoptosis in lesional T lymphocytes may be indicative of longer remission time following treatment of psoriasis.

Monitoring photoproduct formation and photobleaching by fluorescence spectroscopy has the potential to improve PDT dosimetry with a verteporfin-like photosensitizer

In current clinical practice, photodynamic therapy (PDT) is carried out with prescribed drug doses and light doses as well as fixed drug-light intervals and illumination fluence rates. This approach can result in undesirable treatment outcomes of either overtreatment or undertreatment because of biological variations between different lesions and patients. In this study, we explore the possibility of improving PDT dosimetry by monitoring drug photobleaching and photoproduct formation. The study involved 60 mice receiving the same drug dose of a novel verteporfin-like photosensitizer, QLT0074, at 0.3 mg/kg body weight, followed by different light doses of 5, 10, 20, 30, 40 or 50 J/cm2 at 686 nm and a fluence rate of 70 mW/cm2. Photobleaching and photoproduct formation were measured simultaneously, using fluorescence spectroscopy. A ratio technique for data processing was introduced to reliably detect the photoproduct formed by PDT on mouse skin in vivo. The study showed that the QLT0074 photoproduct is stable and can be reliably quantified. Three new parameters, photoproduct score (PPS), photobleaching score (PBS) and percentage photobleaching score (PBS%), were introduced and tested together with the conventional dosimetry parameter, light dose, for performance on predicting PDT-induced outcome, skin necrosis. The statistical analysis of experimental results was performed with an ordinal logistic regression model. We demonstrated that both PPS and PBS improved the prediction of skin necrosis dramatically compared to light dose. PPS was identified as the best single parameter for predicting the PDT outcome.

Systemic photodynamic therapy with aminolaevulinic acid delays the appearance of ultraviolet-induced skin tumours in mice

BACKGROUND

Photodynamic therapy (PDT) with topical aminolaevulinic acid (ALA) has recently been approved by the US Food and Drug Administration for the treatment of actinic keratoses.

OBJECTIVES

To determine whether weekly systemic suberythemogenic ALA-PDT could prevent the appearance of ultraviolet (UV) -induced skin tumours in hairless mice.

METHODS

One group of 20 mice received daily UV radiation from FS 20 tubes, and weekly intraperitoneal injections of ALA 40 mg kg(-1), each followed 3 h later by 12 J cm(-2) of white light (ALA-PDT). Control groups consisted of mice exposed only to UV, to UV and ALA without white light, or UV and white light without ALA, as well as untreated mice.

RESULTS

The tumour-free survival was significantly longer for mice exposed to daily UV and weekly ALA-PDT as compared with the control groups. Neither the mortality nor the incidence of large skin tumours was higher in the UV/ALA-PDT group than in mice exposed only to UV. In vivo fluorescence spectroscopy showed that the 635-nm fluorescence emission within tumours was lower than in normal skin 3 h after ALA administration. This was also confirmed by quantitative fluorescence microscopy.

CONCLUSIONS

Systemic ALA-PDT can delay the appearance of UV-induced skin tumours in mice without increasing mortality or the incidence of large tumours.

Photodynamic therapy with 5-aminolevulinic acid induces apoptosis and caspase activation in malignant T cells

BACKGROUND

Preliminary studies have suggested that photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) can improve psoriasis and mycosis fungoides, two diseases where normal or malignant T cells play a central role.

OBJECTIVES

To determine if ALA-PDT induces apoptosis and caspase activation in Jurkat cells, a malignant T-cell line.

METHODS

Jurkat cells were incubated with ALA in the presence of [14C]-thymidine followed by red light exposure. DNA fragmentation was measured 24 hours later with a DNA elution assay. The influence on DNA fragmentation of ALA concentration, time between ALA addition and light exposure, as well as light fluence were studied. The occurrence of oligonucleosome-sized DNA fragmentation was also studied with DNA electrophoresis. Caspase-3-like activity was monitored by measuring Ac-DEVD-AMC hydrolysis.

RESULTS

DNA fragmentation as high as 88% was observed 24 hours after ALA-PDT. The percentage of DNA fragmentation increased with increasing doses of ALA, red light fluence, as well as longer incubation time with ALA. DNA fragmentation was observed as early as 3 hours after ALA-PDT. The presence of apoptosis after ALA-PDT was confirmed by DNA electrophoresis. An increase in caspase-3-like activities was detected following ALA-PDT.

CONCLUSION

ALA-PDT induces apoptosis and caspase-3-like activation in Jurkat cells.

Topical photodynamic therapy with 5-aminolaevulinic acid does not induce hair regrowth in patients with extensive alopecia areata

BACKGROUND

Photodynamic therapy (PDT) is a new modality involving the administration of a photosensitizer, or photosensitizer precursor, followed by its activation with light to generate a therapeutic effect. 5-Aminolaevulinic acid (ALA) is a photosensitizer precursor that is transformed by cells into protoporphyrin IX (PpIX), which can in turn be activated by red light.

OBJECTIVES

To investigate the effect of PDT in alopecia areata (AA).

METHODS

In six patients with extensive AA, topical ALA lotion at 5%, 10% and 20% as well as the vehicle lotion alone were applied separately to different scalp areas, followed 3 h later by exposure to red light at each treatment session.

RESULTS

No significant hair growth was observed after 20 twice-weekly treatment sessions. A significant increase in erythema and pigmentation was observed for the three concentrations of ALA lotion vs. the vehicle, implying that a phototoxic PDT effect was achieved in the skin. In vivo fluorescence spectroscopy in one patient showed an increase in red PpIX fluorescence 3 h after ALA application followed by a decrease after light exposure. On fluorescence microscopy, bright red fluorescence was present in the epidermis and sebaceous glands, but not in the inflammatory infiltrate surrounding the hair follicle following ALA application.

CONCLUSIONS

PDT was ineffective in the treatment of AA.

Photodynamic therapy in dermatology

The combination of light and chemicals to treat skin diseases is widely practiced in dermatology. Within this broad use of light and drugs, in recent years the concept of photodynamic therapy (PDT) has emerged. PDT is a promising modality for the management of various tumors and nonmalignant diseases, based on the combination of a photosensitizer that is selectively localized in the target tissue and illumination of the lesion with visible light, resulting in photodamage and subsequent cell death. Moreover, the fluorescence of photosensitizing compounds is also utilized as a helpful diagnostic tool for the detection of neoplastic tissue. Intensive basic and clinical research culminated in the worldwide approval of PDT for bladder, esophageal, and lung cancer. The expanding use of this relatively new therapeutic modality in dermatology at many centers around the world has revealed its efficacy for the treatment of cutaneous precancer and cancer, as well as selected benign skin disorders. The following article summarizes the main principles of PDT considering the most recent developments and provides a comprehensive synopsis of the present status of the use of PDT in dermatology. (J Am Acad Dermatol 2000;42:389-413.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be able to describe the basic concepts of PDT, including fundamental knowledge of the most relevant photosensitizers, the light sources, the mechanisms involved in PDT-mediated cell destruction, as well as the indications and limitations of photodynamic treatment of skin diseases.

In vitro and in vivo evaluation of hypericin for photodynamic therapy of equine sarcoids

The therapeutic potential of the photodynamic compound, hypericin, in the treatment of equine sarcoids was evaluated. The in vitro cytotoxicity was assessed using three equine cell lines and the observed phototoxic effect was comparable to that on different highly sensitive human cell lines and significantly influenced by the energy density used although independent of the cell type. The in vivo antitumoural action of photodynamic therapy using hypericin was evaluated on three equine sarcoids in a donkey. Four intratumoural injections were given and the tumours were illuminated daily during 25 days. An 81% reduction in tumour volume was obtained at the end of therapy and 2 months later, a 90% reduction was observed. Further experimental work should be performed, but these results suggest that photodynamic therapy using hypericin has a potential for the non-invasive treatment of equine sarcoids.

Skin photosensitization with topical hypericin in hairless mice

Hypericin, a naturally occurring photosensitizer, exhibits interesting in vitro photobiological activities, which suggest that the compound is a potential antipsoriatic agent. In this study, the possibility of hypericin penetrating the skin in photo-active concentrations has been studied. Hypericin is incorporated in either emulsifying ointment supplemented with solketal (hypericin content: 0.05%) or in polyethylene glycol (PEG) ointment (hypericin content: 0.5%) and applied to the skin of hairless mice for 4 h. After removing excess ointment, the mice are then irradiated with different light doses using a 500 W halogen lamp. As a positive control, intraperitoneally (i.p.) administered hypericin (10 and 40 mg/kg) has also been tested. Erythema, desquamation and erosions are demonstrated in the mice treated with hypericin in emulsifying ointment with solketal using a light dose of at least 4.5 J/cm2. In general, these reactions correlate well with those of i.p. administered hypericin (40 mg/kg), indicating that hypericin incorporated in emulsifying ointment with solketal is well absorbed by the skin of the mice. However, for the i.p. administered hypericin (40 mg/kg), we could not evaluate phototoxic reactions in the group of animals that received a light dose of 108 J/cm2, as they all died 12-24 h after irradiation, indicating extreme photosensitization with systemic hypericin at higher light doses. On the contrary, there is no measurable skin photosensitivity induced by hypericin when incorporated in PEG ointment or when 10 mg/kg hypericin is i.p. administered. Our results show that hypericin incorporated in a suitable vehicle can be delivered to the skin in photo-active concentrations. Using a vehicle such as emulsifying ointment with solketal, it will be possible to explore the photo-activity of hypericin in the treatment of psoriasis and other skin diseases.

Advances in dermatologic lasers

Lasers continue to fundamentally redefine the nature of dermatologic practice. Recent advances in dermatologic lasers have focused on refining the process of selective photothermolysis, as well as evaluating new devices and treatment indications. Despite the current multiplicity of available lasers and associated marketing claims, what is perhaps most lacking are data comparing the efficacy of different lasers that can be used to treat the same condition, and data on the long term benefits of laser treatment.