Application of leukotriene B4 and reflectance confocal microscopy as a noninvasive in vivo model to study the dynamics of skin inflammation

Noninvasive analysis and minimally invasive in vivo experimental challenges of the skin barrier

In this review, we aim to give a concise and selective overview of noninvasive biophysical analysis techniques for skin barrier analysis (transepidermal water loss, electrical methods, confocal Raman microspectroscopy, sebumeter, reflectance spectrophotometry, tristimulus colorimetry, diffuse reflectance spectroscopy and reflectance confocal microscopy), including advantages and limitations. Rather than giving an exhaustive description of the many techniques currently available, we show the usefulness of a representative selection of techniques in the functional and morphological evaluation of the skin barrier. Furthermore, we introduce human minimally invasive skin challenging models as a means to study the mechanisms regulating skin homoeostasis and disease and subsequently show how biophysical analysis techniques can be combined with these in vivo skin challenging models in the functional and morphological evaluation of the skin barrier in healthy human skin. We are convinced that the widespread application of biophysical analysis techniques in dermatological practice and in cosmetic sciences will prove invaluable in offering personalized and noninvasive skin treatment solutions. Furthermore, combining the human in vivo challenging models with these novel noninvasive techniques will provide valuable methodology and tools for detailed characterization of the skin barrier in health and disease.

Current and future applications of confocal laser scanning microscopy imaging in skin oncology

Confocal laser scanning microscopy (CLSM) is a modern imaging technique that enables the in vivo or ex vivo characterization of skin lesions located in the epidermis and superficial dermis with a high quasi-microscopic resolution. Currently, it is considered to be the most promising imaging tool for the evaluation of superficial skin tumors. The in vivo mode adds the advantage of noninvasive, dynamic, in real-time assessment of the tumor associated vasculature and inflammation. It offers the possibility to repeatedly examine the same skin area without causing any damage and to monitor disease progression and treatment outcome. Furthermore, this novel technology allows the evaluation of the entire lesion and can be used to guide biopsies and to define tumor margins before surgical excision or other invasive therapies. CLSM diagnostic features may differentiate between the various histologic subtypes of skin tumors and therefore helps in choosing the best therapeutic approach. In this study, we present the CLSM characteristic features of the most common melanocytic and non-melanocytic skin tumors, as well as future possible CLSM applications in the study of experimental skin tumorigenesis on animal models.

Noninvasive Skin Barrier Assessment: Multiparametric Approach and Pilot Study

The epidermal barrier function is disrupted in various inflammatory skin diseases. Accurate methods to measure skin barrier function are needed to assess the effect of therapeutic agents. Therefore, we developed a noninvasive multiparametric approach to measure four different parameters regarding the skin barrier. In the current pilot study, we evaluate this method in 14 healthy volunteers. We assessed erythema, transepidermal water loss (TEWL), water content, and epidermal thickness at both cheeks before and 30 min after application of Lanette and Vaseline-Lanette cream. For this, we used spectrophotometry, the Aquaflux device, the Epsilon device, and reflection confocal microscopy, respectively. Stratum corneum (SC) thickness was significantly increased after application of both creams (p < 0.05), and this increase was larger after Lanette cream compared to after Vaseline-Lanette cream (p = 0.035). Erythema, TEWL, and water content did not significantly change after cream application. Our multiparametric approach is promising and offers a feasible and practical way to quickly obtain multifaceted information about skin barrier function. Further exploration of this approach after prolonged use of cream and in conditions of disrupted skin barrier are recommended areas for future research.

In vivo confocal laser scanning microscopy imaging of skin inflammation: Clinical applications and research directions

In vivo confocal laser scanning microscopy (CLSM) is a novel imaging technique that provides noninvasive, morphological characterization of skin structures with a resolution that is very close to that of light microscopy. Moreover, as it allows repeated imaging of the same skin area at different time-points, it is an excellent method for monitoring disease course, response to treatment or specific stimuli and a path to study dynamic phenomena in real-time. To date, two different variants of in vivo CLSM have been authorized in dermatological field, namely the reflectance confocal microscopy predominantly for clinical diagnosis and the fluorescence confocal microscopy mainly for research purposes. This study describes the principles of in vivo CLSM technique, its role in the diagnosis and monitoring of inflammatory skin diseases, as well as some promising research directions to study the dynamics of skin inflammation using this method. In vivo CLSM evaluation of inflammatory dermatoses and of the skin inflammatory component in various diseases has an undoubted potential with broad applications ranging from clinical, morphological to experimental, functional studies involving the skin.

Identification of Objective Morphometric Markers of Xerostomia in the Oral Mucosa Epithelium with In Vivo Confocal Microscopy

The purpose of this work was to determine whether the morphology of the oral mucosa epithelium (OME) of patients with xerostomia differ from patients without xerostomia. In total, 34 patients with dry eye disease (DED) with or without xerostomia were examined at The Norwegian Dry Eye Disease Clinic with in vivo confocal microscopy of the lower lip. In addition, age- and gender-matched healthy controls (HC) were included. DED patients with xerostomia had a higher superficial to deep backscatter ratio compared with DED patients without xerostomia (p=0.002) and HC (p=0.001). Regression analysis demonstrated that this ratio was related to xerostomia independently of gender and age (p<0.001). Sensitivity and specificity of detecting xerostomia were 0.78 and 0.85, respectively, when using a superficial to deep backscatter ratio cut-off value of 0.995 (p=0.004). The mean nucleus to cytosol backscatter ratio in the superficial OME was lower in patients with xerostomia than in those without xerostomia (p=0.034). In vivo confocal microscopy is a potential tool for evaluating the oral cavity and to assess changes in the OME associated with xerostomia, objectively and quantitatively. The cause of the increased backscatter in the superficial OME in xerostomia, however, remains to be elucidated.

Effect of Radix Stemonae concentrated decoction on the lung tissue pathology and inflammatory mediators in COPD rats

Background

Chronic obstructive pulmonary disease (COPD) is a common and frequently occurring respiratory disease. At present, western medicine treatment of COPD mainly focuses on symptomatic treatment. Using Chinese medicines or integrated Chinese and Western medicines to treat stable COPD has significant efficacy. In this study, we aimed to observe the effect of Radix Stemonae concentrated decoction on the lung tissue pathology and inflammatory mediators in COPD rats and explore its possible mechanism.

Methods

SD rats were randomized into blank group, COPD model group and Radix Stemonae group, 10 cases in each group. Rats were fed for 112 days. Before the rats were sacrificed, lung function of the animals was tested. The right lower lung was fixed for morphologic observation. The inflammatory mediators in serum were determined using enzyme-linked immuno sorbent assay.

Results

Body weight of animals in the model group was significantly decreased compared with blank group (P < 0.05). After gavage therapy with Radix Stemonae, body weight was significantly increased (P < 0.05). Compared with the blank group, pulmonary functions of rats in the model group were significantly abnormal (P < 0.05), while in Radix Stemonae group, these indicators turned much better than model group (P < 0.05). As for pathological changes in lungs, airway inflammation in the model group was aggravated. In the Radix Stemonae group, inflammation and emphysema were much milder. The concentrations of TNF-α, IL-8 and LTB4 in both model group and Radix Stemonae group were increased significantly (P < 0.05). But the levels in Radix Stemonae group were decreased significantly than model group (P < 0.05).

Conclusion

Radix Stemonae concentrated decoction may mitigate and improve airway rebuilding in the lungs of COPD rats by inhibiting the release of inflammatory mediators.

Diagnosis of Basal Cell Carcinoma by Reflectance Confocal Microscopy: Study Design and Protocol of a Randomized Controlled Multicenter Trial

Background

Skin cancer, including basal cell carcinoma (BCC), has become a major health care problem. The limitations of a punch biopsy (at present the gold standard) as diagnostic method together with the increasing incidence of skin cancer point out the need for more accurate, cost-effective, and patient friendly diagnostic tools. In vivo reflectance confocal microscopy (RCM) is a noninvasive imaging technique that has great potential for skin cancer diagnosis.

Objective

To investigate whether in vivo RCM can correctly identify the subtype of BCC and to determine the cost-effectiveness of RCM compared with punch biopsy (usual care). Study design: Randomized controlled multicenter trial.

Methods

On the basis of 80% power and an alpha of 0.05, 329 patients with lesions clinically suspicious for BCC will be included in this study. Patients will be randomized for RCM or for a punch biopsy (usual care). When a BCC is diagnosed, surgical excision will follow and a follow-up visit will be planned 3 months later. Several questionnaires will be filled in (EQ-5D, EQ-5D VAS, iMTA PCQ, and TSQM-9). We will perform statistical analysis, cost-effectiveness, and patient outcome analysis after data collection.

Results

This research started in January 2016 and is ethically approved. We expect to finish this study at the end of 2018.

Conclusions

In this study, we will investigate whether RCM is at least as good in identifying BCC subtypes as conventional pathological investigation of skin biopsies. Anticipating that RCM is found to be a cost-effective alternative, it saves on direct medical consumption like labor of the pathologist and other medical personnel as well as materials related to treatment failure with at least equal effectiveness.

Trial Registration

Clinicaltrials.gov NCT02623101; https://clinicaltrials.gov/ct2/show/NCT02623101 (Archived by WebCite at http://www.webcitation.org/6id54WQa2)