Biological Effects of Ingenol Mebutate Gel in Moderate to Severe Actinic Fields Assessed by Reflectance Confocal Microscopy: A Phase I Study.

Ingenol mebutate represents a topical treatment for fields with actinic keratosis (AK). The biological effects of ingenol mebutate in AK, subclinical (SC)-AK, and reference-skin were assessed and graded by in vivo reflectance confocal microscopy (RCM) and histology. Patients with AK and SC-AK lesions in one 25 cm2 field on hands or forearms, and with an area of reference skin on the inner upper arm, were included. The two fields were each treated with ingenol mebutate 0.05% gel (n=16), or vehicle (n=8), on 2 consecutive days; clinical and RCM assessments were performed on days 1, 2, 3, 8, and 57, and biopsies on day 3. Local skin responses were more pronounced in AK fields (6.1 (mean) ± 2.6 (SD)) compared with reference skin (3.5 ± 1.5). The clinical AK lesion reduction was 43.8% and 6.3% with ingenol mebutate and vehicle, respectively. RCM and histology evaluations showed that ingenol mebutate induced a significant pronounced cell death and immune response in AK and SC-AK lesions, compared with reference skin. Ingenol mebutate induced RCM-measured reduction in (investigator-1/investigator-2): AK lesions (34/28%), SC-AK lesions (72/56%), and solar elastosis in AK fields (mean, -0.22/-0.25). In conclusion, ingenol mebutate showed selective pronounced biological responses in AK and SC-AK as compared with reference skin.

J Drugs Dermatol. 2016;15(10):1181-1189.

In vivo confocal microscopy in dermatology: from research to clinical application.

Confocal laser scanning microscopy (CLSM) represents an emerging technique for the noninvasive histomorphological analysis of skin in vivo and has shown its applicability for dermatological research as well as its value as an adjunct tool in the clinical management of skin cancer patients. Herein, we aim to give an overview on the current clinical indications for CLSM in dermatology and also highlight the diverse applications of CLSM in dermatological research.

Applicability of confocal laser scanning microscopy for evaluation and monitoring of cutaneous wound healing.

There is a high demand for noninvasive imaging techniques for wound assessment. In vivo reflectance confocal laser scanning microscopy (CLSM) represents an innovative optical technique for noninvasive evaluation of normal and diseased skin in vivo at near cellular resolution. This study was designed to test the feasibility of CLSM for noninvasive analysis of cutaneous wound healing in 15 patients (7 male/8 female), including acute and chronic, superficial and deep dermal skin wounds. A commercially available CLSM system was used for the assessment of wound bed and wound margins in order to obtain descriptive cellular and morphological parameters of cutaneous wound repair noninvasively and over time. CLSM was able to visualize features of cutaneous wound repair in epidermal and superficial dermal wounds, including aspects of inflammation, neovascularisation, and tissue remodelling in vivo. Limitations include the lack of mechanic fixation of the optical system on moist surfaces restricting the analysis of chronic skin wounds to the wound margins, as well as a limited optical resolution in areas of significant slough formation. By describing CLSM features of cutaneous inflammation, vascularisation, and epithelialisation, the findings of this study support the role of CLSM in modern wound research and management.

Consistency and distribution of reflectance confocal microscopy features for diagnosis of cutaneous T cell lymphoma.

Reflectance confocal microscopy (RCM) represents a noninvasive imaging technique that has previously been used for characterization of mycosis fungoides (MF) in a pilot study. We aimed to test the applicability of RCM for diagnosis and differential diagnosis of MF in a clinical study. A total of 39 test sites of 15 patients with a biopsy-proven diagnosis of either MF, parapsoriasis, Sézary syndrome, or lymphomatoid papulosis were analyzed for presence and absence of RCM features of MF. Cochran and Chi(2) analysis were applied to test the concordance between investigators and the distribution of RCM features, respectively. For selected parameters, the Cochran analysis showed good concordance between investigators. Inter-observer reproducibility was highest for junctional atypical lymphocytes, architectural disarray, and spongiosis. Similarly, Chi(2) analysis demonstrated that selected features were present at particularly high frequency in individual skin diseases, with values ranging from 73% to 100% of all examined cases.

The use of reflectance confocal microscopy for monitoring response to therapy of skin malignancies.

SUMMARY: Reflectance confocal microscopy (RCM) is a new non-invasive imaging technique that enables visualizing cells and structures in living skin in real-time with resolution close to that of histological analysis. RCM has been successfully implemented in the assessment of benign and malignant lesions. Most importantly, it also enables monitoring dynamic changes in the skin over time and in response to different therapies, e.g., imiquimod, photodynamic therapy, and others. Given the often traumatic nature of skin cancer that affects both the physiology and the psychology of the patients, it is crucial to have methods that enable monitoring the response to treatment but that minimize the distress and discomfort associated with such process. This article provides a very brief overview of the fundamentals of RCM and then focuses on its recent employment as a monitoring tool in skin cancer and other pathologies that may require frequent follow-up.

Reflectance confocal microscopy for the evaluation of acute epidermal wound healing.

The dynamic process of wound healing is routinely evaluated by clinical or histological evaluation. Recently, a number of non-invasive imaging techniques have been evaluated for their clinical applicability in dermatology. Among them, reflectance confocal microscopy (RCM) represents a non-invasive imaging technique that allows the in vivo characterization of the skin at near-histological resolution. The aim of this study was to monitor epidermal wound repair using RCM in a model of tissue damage induced by cryosurgery. For this purpose, contact cryosurgery was performed at -32 °C for 10 seconds on the volar forearm of five healthy volunteers. Clinical and RCM evaluations were performed at nine consecutive time points. RCM allowed the visualization of edema formation and blood vessel dilatation immediately after cryosurgery, as well as morphologic features of wound repair, including the formation of finger-like protusions of keratinocytes into the wound bed, the appearance of hairpin-like vessels, and inflammatory cells. This pilot study illustrates that RCM represents a promising technique for quasi-real-time monitoring the kinetics of wound repair non-invasively and over time, thus offering new insights into in vivo processes of cutaneous wound repair and angiogenesis, as well as potential effects of topically applied drugs on the process of tissue repair.

Modes of action of diclofenac 3%/hyaluronic acid 2.5% in the treatment of actinic keratosis.

BACKGROUND: The efficacy of topically applied diclofenac 3 % in combination with hyaluronic acid 2.5 % in the treatment of actinic keratoses (AKs) has been demonstrated in several clinical studies, but the exact mode of action is still unclear. This study evaluates the potential molecular and cellular main modes of action of topically applied diclofenac in the treatment of AKs. PATIENTS AND METHODS: In this prospective study 20 male patients with AKs were treated for 90 days with topically applied diclofenac 3 %/hyaluronic acid 2.5 %. Before and after treatment, skin biopsies were taken from the treatment area and were investigated histologically and immunohistochemically as well as compared to healthy skin. For this purpose, markers for inflammation (COX-2, CD3, CD8), apoptosis (p53), cell cycle arrest (p53, p21), proliferation (Ki67), and angiogenesis (CD31) were examined. RESULTS: The immunohistochemical analysis demonstrated a significant decrease in expression of COX-2, CD3 and CD8. Furthermore, there was a clear reduction of CD31 expression as a marker for angiogenetic processes. Additionally, there was a tendency toward a reduction in markers for proliferation and apoptosis. CONCLUSIONS: The efficacy of diclofenac 3 %/hyaluronic acid 2.5 % in the treatment of AKs is probably due to anti-inflammatory and anti-angiogenic effects, potentially associated with anti-proliferative and apoptosis-inducing underlying mechanisms.

Clinical application of multiphoton tomography in combination with confocal laser scanning microscopy for in vivo evaluation of skin diseases.

Multiphoton tomography (MPT) is an in vivo imaging technique with very high spatial resolution and efforts are made to combine MPT with other non-invasive imaging methods. The goals of the present study were the description of the features of different dermatological entities as seen in MPT and confocal laser scanning microscopy (CLSM) comparison of these two novel techniques and the 'classical' diagnostic measures visual inspection, dermoscopy and histology with respect to the strengths and weaknesses of the different methods and the potential benefit from their combined implementation. After study approval by the local Ethics Committee, 47 patients (31 male, 16 female, age range: 24-88 years) were recruited from the Department of Dermatology of the University Hospital Jena. In this work, we present an illustrative selection of eleven cases from a clinical study combining in vivo MPT with in vivo CLSM. The patients presented with a broad range of dermatological disorders including seborrheic keratoses, angioma, actinic keratoses, melanocytic nevi, malignant melanoma, psoriasis, pemphigus vulgaris and scarring. Both methods, CLSM and MPT, were found to be suitable for in vivo imaging of superficial skin layers and may therefore be useful in dermatological practice for the diagnosis of skin diseases. However, both methods differ in their technical and physical principles. Thus, despite of many similarities concerning the morphological presentation of cells and tissues, important differences are recognized. Synergies of the combination of CLSM and MPT may be obtained by combined implementation in order to benefit from the fast overview given by CLSM and the detailed imaging of skin structures by MPT.

Non-invasive imaging techniques in the diagnosis of skin diseases.

INTRODUCTION: In recent years, there has been an increasing interest in non-invasive imaging techniques in clinical and investigational dermatology. Besides the growing number of biophysical methods for the assessment of skin properties, novel imaging tools have emerged and classical imaging methods are substantially improved. AREAS COVERED: This review focuses on well established and some of the most promising imaging techniques for application in dermatology and cutaneous research. These comprise dermoscopy, sonography, confocal microscopy, multiphoton tomography and optical coherence tomography. Non-invasive imaging techniques are presented concerning their functional principles, the history of their development and their current clinical and research application. Advantages and limitations of each of the methods are discussed. EXPERT OPINION: Available non-invasive imaging techniques in dermatology show substantial differences concerning their limitations and opportunities, potential clinical applicability and practicability. Also, the current data available differ largely between these methods due to different levels of experience in research and clinical application. Future research will not only aim at improving current technical limitations, but also investigate the potential synergistic effects of combining two or more techniques in order to enhance their diagnostic impact.