Marina Venturini

Photodynamic therapy: update 2006. Part 1: Photochemistry and photobiology.

Photodynamic therapy (PDT) is a two‐step therapeutic technique in which the topical or systemic delivery of photosensitizing drugs is followed by irradiation with visible light. Activated photosensitizers transfer energy to molecular oxygen, generating reactive oxygen species (ROS). The subsequent oxidation of lipids, amino acids and proteins induces cell necrosis and apoptosis. In addition, ROS indirectly stimulate the transcription and release of inflammatory mediators. The photosensitizers are selective, in that they penetrate and accumulate in tumour cells or in the endothelium of newly formed vessels while generally avoiding the surrounding healthy tissue. The mechanisms of penetration through the cell membrane and the pattern of subcellular localization strongly influence the type of cellular effect.

Reflectance Confocal Microscopy for In Vivo Skin Imaging

Reflectance confocal microscopy (RCM) is a novel noninvasive technique for “in vivo” examination of the skin. In a confocal microscope, near‐ infrared light from a diode laser is focused on a microscopic skin target. As this light passes between cellular structures having different refraction indexes, it is naturally reflected, and this reflected light is then captured and recomposed into a two‐dimensional gray scale image by computer software. Focusing the microscope (adjusting the focal point on the z‐axis) allows images to be obtained of different levels within the skin. Commercially available microscope systems of this type can create images with enough detail for use in histological analysis. The first investigations using these microscopes served to identify the appearance of the various cell populations living in the different layers of normal skin. Today, the main interest has become focused on the use of these microscopes as a diagnostic tool: a means of investigating benign and malignant tumors of melanocytes and keratinocytes, and, more importantly, the findings of this field of study can be used to develop a diagnostic algorithm which would be not only highly sensitive but specific as well. The aim of the paper is to provide an updated literature review and an in‐depth critique of the state‐of‐the‐art of RCM for skin cancer imaging with a critical discussion of the possibilities and limitations for clinical use.

Methylaminolaevulinate‐based photodynamic therapy of Bowen’s disease and squamous cell carcinoma

Background  Photodynamic therapy (PDT) with methylaminolaevulinate (MAL) is an approved noninvasive treatment option for actinic keratosis and Bowen’s disease (BD), two precursors of invasive squamous cell carcinoma (SCC).

Cutaneous distribution of plasmacytoid dendritic cells in lupus erythematosus. Selective tropism at the site of epithelial apoptotic damage

Recent evidences suggest a significant role of Plasmacytoid dendritic cells (PDC) role in the pathogenesis of lupus erythematosus (LE) via production of type I IFN. Taking advantage on the availability of multiple reagents (CD123, BDCA2, and CD2ap) specifically recognizing PDC on fixed tissues, we investigated the occurrence of PDC in a cohort of 74 LE patients. The large majority of LE biopsies (67/74; 90.5%) showed cutaneous infiltration of PDC. PDC were more frequently observed (96.4 vs 72.2) and numerous in cutaneous LE compared to systemic LE (SLE) and correlated with the density of the inflammatory infiltrate (r=0.40; p<0.001). PDC reduction in SLE might be related to a broader tissue distribution of this cellular population, as indicated by their occurrence in kidneys in 11 out of 24 (45.8%) cases studied. The distribution of cutaneous PDC showed two distinct patterns. More commonly, PDC were observed within perivascular inflammatory nodules in the dermis, associated with CD208+ mature DC and T-bet+ cells [D-PDC]. A second component was observed along the dermal-epithelial junction [J-PDC], in association with cytotoxic T-cells in areas of severe epithelial damage. Notably, chemerin reactivity was observed in 64% of LE biopsies on endothelial cells and in the granular layer keratinocytes. Cutaneous PDC in LE strongly produced type I IFN, as indicated by the diffuse MxA expression, and the cytotoxic molecule granzyme B. This study confirms cutaneous PDC infiltration as hallmark of LE. The topographical segregation in D-PDC and J-PDC suggests a novel view of the role of these cells in skin autoimmunity.

Photodynamic Antifungal Chemotherapy

The growing resistance against antifungal drugs has renewed the search for alternative treatment modalities, and antimicrobial photodynamic therapy (PDT) seems to be a potential candidate. Preliminary findings have demonstrated that dermatophytes and yeasts can be effectively sensitized in vitro and in vivo by administering photosensitizers (PSs) belonging to four chemical groups: phenothiazine dyes, porphyrins and phthalocyanines, as well as aminolevulinic acid, which, while not a PS in itself, is effectively metabolized into protoporphyrin IX. Besides efficacy, PDT has shown other benefits. First, the sensitizers used are highly selective, i.e., fungi can be killed at combinations of drug and light doses much lower than that needed for a similar effect on keratinocytes. Second, all investigated PSs lack genotoxic and mutagenic activity. Finally, the hazard of selection of drug resistant fungal strains has been rarely reported. We review the studies published to date on antifungal applications of PDT, with special focus on yeast, and aim to raise awareness of this area of research, which has the potential to make a significant impact in future treatment of fungal infections.

Photodynamic therapy of interdigital mycoses of the feet with topical application of 5-aminolevulinic acid

Background: Findings of in vitro studies have demonstrated that dermatophytes and yeasts can be effectively photosensitized after topical delivery of 5‐aminolevulinic acid (ALA). This procedure, called photodynamic therapy (PDT), seems to lack mutagenic activity and hazard of selection of drug‐resistant strains.

Photodynamic therapy for basal cell carcinoma: clinical and pathological determinants of response

Background  Photodynamic therapy (PDT) is increasingly used in the treatment of basal cell carcinoma (BCC). However, scant information is available about the impact of both patient‐ and lesion‐related characteristics on the effectiveness of therapy. Therefore, on the basis of the current data, it is difficult to draw clear‐cut indications to use PDT for treatment of BCC in clinical practice.

Clinical and molecular characterization of 40 patients with classic Ehlers–Danlos syndrome: identification of 18 COL5A1 and 2 COL5A2 novel mutations

BackgroundClassic Ehlers–Danlos syndrome (cEDS) is a rare autosomal dominant connective tissue disorder that is primarily characterized by skin hyperextensibility, abnormal wound healing/atrophic scars, and joint hypermobility. A recent study demonstrated that more than 90% of patients who satisfy all of these major criteria harbor a type V collagen (COLLV) defect.MethodsThis cohort included 40 patients with cEDS who were clinically diagnosed according to the Villefranche nosology. The flowchart that was adopted for mutation detection consisted of sequencing the COL5A1 gene and, if no mutation was detected, COL5A2 analysis. In the negative patients the presence of large genomic rearrangements in COL5A1 was investigated using MLPA, and positive results were confirmed via SNP-array analysis.ResultsWe report the clinical and molecular characterization of 40 patients from 28 families, consisting of 14 pediatric patients and 26 adults. A family history of cEDS was present in 9 patients. The majority of the patients fulfilled all the major diagnostic criteria for cEDS; atrophic scars were absent in 2 females, skin hyperextensibility was not detected in a male and joint hypermobility was negative in 8 patients (20% of the entire cohort). Wide inter- and intra-familial phenotypic heterogeneity was observed. We identified causal mutations with a detection rate of approximately 93%. In 25/28 probands, COL5A1 or COL5A2 mutations were detected. Twenty-one mutations were in the COL5A1 gene, 18 of which were novel (2 recurrent). Of these, 16 mutations led to nonsense-mediated mRNA decay (NMD) and to COLLV haploinsufficiency and 5 mutations were structural. Two novel COL5A2 splice mutations were detected in patients with the most severe phenotypes. The known p. (Arg312Cys) mutation in the COL1A1 gene was identified in one patient with vascular-like cEDS.ConclusionsOur findings highlight that the three major criteria for cEDS are useful and sufficient for cEDS clinical diagnosis in the large majority of the patients. The borderline patients for whom these criteria fail can be diagnosed when minor signs of connective tissue diseases and family history are present and when genetic testing reveals a defect in COLLV. Our data also confirm that COL5A1 and COL5A2 are the major, if not the only, genes involved in cEDS.

Photodynamic therapy: update 2006 Part 2: Clinical results

In several randomized, controlled studies, the application of a standard preparation containing methyl‐aminolevulinate (MAL; Metvix®, Galderma, F), followed by red light irradiation proved effective and well tolerated in the treatment of actinic keratosis and basal cell carcinoma, and has now been approved for clinical use in European countries. A brand name aminolevulinic acid (ALA) solution (Levulan Kerastick®, Dusa Pharmaceuticals Inc., Wilmington, MA) plus blue light exposure has been approved for the treatment of actinic keratosis in the USA. Randomized and controlled studies have shown that MAL as well as ALA are also effective in the treatment of Bowens disease. In addition, a large and growing number of open studies or case reports have evaluated its use in the treatment of a broad range of other neoplastic, inflammatory and infectious skin diseases. However, efficacy and definite advantages over standard therapies remain to be clarified because the experimental design of these studies was often poor, the number of enrolled patients was generally low, and the follow‐up was shorter than 12 months. However, these studies have suggested a few possible clinical applications worthy of further investigation. A growing number of laboratory and clinical findings suggest that several new synthetic sensitizers, besides ALA and MAL, may be helpful in the treatment of non‐melanoma skin cancers, melanoma metastasis, and selected inflammatory and infective skin diseases. These compounds are deliverable intravenously, have short half‐lives both in the blood and skin, and are highly efficient. However, they are as of yet not approved for clinical use.

Oral administration of a hydrophilic extract of Polypodium leucotomos for the prevention of polymorphic light eruption

BACKGROUND Polymorphic light eruption (PLE) is the most common idiopathic photodermatosis. Reactive oxygen species have been implicated in the pathogenesis of PLE. Polypodium leucotomos (PL) is a natural extract from tropical fern leaves with potent antioxidant and anti-inflammatory properties. OBJECTIVE In this study we sought to evaluate whether a concentrated hydrophilic extract of PL might prevent or delay the photoinduction of typical PLE lesions by artificial ultraviolet (UV) radiation. METHODS A total of 35 patients with long-standing PLE were included in this open, uncontrolled bicenter study. PLE was induced by photoprovocation with artificial UVB and UVA light, thereafter oral treatment with PL was initiated. Two weeks later a second photoprovocation was performed while the patients were still taking PL. RESULTS Thirty patients developed PLE lesions after repeated irradiation with UVA. Of these, 18 patients also responded to UVB. After PL treatment, 9 (30%) and 5 (28%) patients, respectively, were unresponsive to repeated UVA and UVB exposure. In the remaining patients, the mean number of UVA and UVB irradiations required to elicit PLE increased significantly from 1.95 to 2.62 (P = .005) and from 2.38 to 2.92 (P = .047), respectively. LIMITATIONS The study was open and uncontrolled and included a relatively small number of patients. CONCLUSION Our data indicate that oral PL treatment might be beneficial for the prevention of PLE.