Topical Corticosteroids Normalize both Skin and Systemic Inflammatory Markers in Infant Atopic Dermatitis

Background: Atopic dermatitis (AD) is the most common inflammatory skin disease. It is highly heterogeneous in clinical presentation, treatment response, disease trajectory and associated atopic comorbidities. Immune biomarkers are dysregulated in skin and peripheral blood. Aims: We used noninvasive skin and peripheral biomarkers to observe the effects of real-world topical corticosteroid (TCS) treatment in infants with AD, by measuring skin and blood biomarkers before and after therapy. Methods: Seventy-four treatment-naïve infants with AD underwent 6 weeks of TCS treatment. Stratum corneum (SC) and plasma blood biomarkers as well as SC natural moisturizing factor (NMF) were measured before and after TCS therapy. Immune markers included innate, T helper (Th)1 and Th2 immunity, angiogenesis, and vascular factors. AD severity was assessed by the Scoring Atopic Dermatitis index, and skin barrier function by transepidermal water loss (TEWL). Twenty healthy infants were recruited as controls. Results: TCS therapy predictably led to improvement in disease severity. Levels of immune markers in the skin and in the peripheral blood showed significant change from baseline, though most did not reach healthy control levels. The most prominent change from baseline in the SC was in markers of innate immune activation, interleukin (IL)-18, IL-8 and IL-1α, and the Th2 chemokines C-C motif chemokine (CCL)17 and CCL22. In blood, the largest changes were in Th2-skewed biomarkers: CCL17, IL-13, CCL22, IL-5, and CCL26. TEWL decreased after therapy; no significant changes from baseline were found for NMF. Conclusions: The profound impact of topical therapy on systemic biomarkers suggests that the skin compartment generates a major component of dysregulated systemic cytokines in infant AD. There may be long-term beneficial effects of correcting systemic immune dysregulation through topical therapy

A minimally invasive tool to study immune response and skin barrier in children with atopic dermatitis

Background: Atopic dermatitis (AD) affects children of all skin types. Most research has focused on light skin types. Studies investigating biomarkers in people with AD with dark skin types are lacking. Objectives: To explore skin barrier and immune response biomarkers in stratum corneum (SC) tape strips from children with AD with different skin types. Methods: Tape strips were collected from lesional and nonlesional forearm skin of 53 children with AD and 50 controls. We analysed 28 immunomodulatory mediators, and natural moisturizing factors (NMF) and corneocyte morphology. Results: Interleukin (IL)-1β, IL-18, C-X-C motif chemokine (CXCL) 8 (CXCL8), C-C motif chemokine ligand (CCL) 22 (CCL22), CCL17, CXCL10 and CCL2 were significantly higher (P < 0·05) in lesional AD skin compared with nonlesional AD skin; the opposite trend was seen for IL-1α. CXCL8, CCL2 and CCL17 showed an association with objective SCORing Atopic Dermatitis score. NMF levels showed a gradual decrease from healthy skin to nonlesional and lesional AD skin. This gradual decreasing pattern was observed in skin type II but not in skin type VI. Skin type VI showed higher NMF levels in both nonlesional and lesional AD skin than skin type II. Corneocyte morphology was significantly different in lesional AD skin compared with nonlesional AD and healthy skin. Conclusions: Minimally invasive tape-stripping is suitable for the determination of many inflammatory mediators and skin barrier biomarkers in children with AD. This study shows differences between children with AD with skin type II and skin type VI in NMF levels, suggesting that some aspects of pathophysiological mechanisms may differ in AD children with light versus dark skin types

Current knowledge on biomarkers for contact sensitization and allergic contact dermatitis.

Contact sensitization is common and affects up to 20% of the general population. The clinical manifestation of contact sensitization is allergic contact dermatitis. This is a clinical expression that is sometimes difficult to distinguish from other types of dermatitis, for example irritant and atopic dermatitis. Several studies have examined the pathogenesis and severity of allergic contact dermatitis by measuring the absence or presence of various biomarkers. In this review, we provide a non-systematic overview of biomarkers that have been studied in allergic contact dermatitis. These include genetic variations and mutations, inflammatory mediators, alarmins, proteases, immunoproteomics, lipids, natural moisturizing factors, tight junctions, and antimicrobial peptides. We conclude that, despite the enormous amount of data, convincing specific biomarkers for allergic contact dermatitis are yet to be described

A mechanistic target of rapamycin complex 1/2 (mTORC1)/V-Akt murine thymoma viral oncogene homolog 1 (AKT1)/cathepsin H axis controls filaggrin expression and processing in skin, a novel mechanism for skin barrier disruption in patients with atopic dermatitis

Background Filaggrin, which is encoded by the filaggrin gene (FLG), is an important component of the skin's barrier to the external environment, and genetic defects in FLG strongly associate with atopic dermatitis (AD). However, not all patients with AD have FLG mutations. Objective We hypothesized that these patients might possess other defects in filaggrin expression and processing contributing to barrier disruption and AD, and therefore we present novel therapeutic targets for this disease. Results We describe the relationship between the mechanistic target of rapamycin complex 1/2 protein subunit regulatory associated protein of the MTOR complex 1 (RAPTOR), the serine/threonine kinase V-Akt murine thymoma viral oncogene homolog 1 (AKT1), and the protease cathepsin H (CTSH), for which we establish a role in filaggrin expression and processing. Increased RAPTOR levels correlated with decreased filaggrin expression in patients with AD. In keratinocyte cell cultures RAPTOR upregulation or AKT1 short hairpin RNA knockdown reduced expression of the protease CTSH. Skin of CTSH-deficient mice and CTSH short hairpin RNA knockdown keratinocytes showed reduced filaggrin processing, and the mouse had both impaired skin barrier function and a mild proinflammatory phenotype. Conclusion Our findings highlight a novel and potentially treatable signaling axis controlling filaggrin expression and processing that is defective in patients with AD

Analytical techniques for multiplex analysis of protein biomarkers

Introduction: The importance of biomarkers for pharmaceutical drug development and clinical diagnostics is more significant than ever in the current shift toward personalized medicine. Biomarkers have taken a central position either as companion markers to support drug development and patient selection, or as indicators aiming to detect the earliest perturbations indicative of disease, minimizing therapeutic intervention or even enabling disease reversal. Protein biomarkers are of particular interest given their central role in biochemical pathways. Hence, capabilities to analyze multiple protein biomarkers in one assay are highly interesting for biomedical research. Areas covered: We here review multiple methods that are suitable for robust, high throughput, standardized, and affordable analysis of protein biomarkers in a multiplex format. We describe innovative developments in immunoassays, the vanguard of methods in clinical laboratories, and mass spectrometry, increasingly implemented for protein biomarker analysis. Moreover, emerging techniques are discussed with potentially improved protein capture, separation, and detection that will further boost multiplex analyses. Expert commentary: The development of clinically applied multiplex protein biomarker assays is essential as multi-protein signatures provide more comprehensive information about biological systems than single biomarkers, leading to improved insights in mechanisms of disease, diagnostics, and the effect of personalized medicine

Analytical techniques for multiplex analysis of protein biomarkers

Introduction: The importance of biomarkers for pharmaceutical drug development and clinical diagnostics is more significant than ever in the current shift toward personalized medicine. Biomarkers have taken a central position either as companion markers to support drug development and patient selection, or as indicators aiming to detect the earliest perturbations indicative of disease, minimizing therapeutic intervention or even enabling disease reversal. Protein biomarkers are of particular interest given their central role in biochemical pathways. Hence, capabilities to analyze multiple protein biomarkers in one assay are highly interesting for biomedical research. Areas covered: We here review multiple methods that are suitable for robust, high throughput, standardized, and affordable analysis of protein biomarkers in a multiplex format. We describe innovative developments in immunoassays, the vanguard of methods in clinical laboratories, and mass spectrometry, increasingly implemented for protein biomarker analysis. Moreover, emerging techniques are discussed with potentially improved protein capture, separation, and detection that will further boost multiplex analyses. Expert commentary: The development of clinically applied multiplex protein biomarker assays is essential as multi-protein signatures provide more comprehensive information about biological systems than single biomarkers, leading to improved insights in mechanisms of disease, diagnostics, and the effect of personalized medicine.</div

Evaluation of in-vivo animal and in-vitro models for prediction of dermal absorption in man

Risk assessment of dermal exposure to chemicals requires percutaneous absorption data to link the external exposure to the systemic uptake. The most reliable data on percutaneous absorption are obtained from in-vivo human volunteer studies. In addition to ethical constrains, the conduct of these studies is not feasible for the large number of industrial chemicals in use today. Therefore, there is an increasing need for alternative methods to determine percutaneous absorption such as in-vitro assays and methods performed in vivo in experimental animals. In this article, recent comparative in-vitro and in-vivo studies on percutaneous absorption have been addressed with emphasis on the factors that may affect the predictive value of the in-vitro models. Furthermore, the use of animal models, in particular the rat skin, in prediction of percutaneous absorption in the human skin has been reviewed. In-vitro assays showed to be largely influenced by the experimental circumstances, such as type and thickness of the skin, receptor fluid, and the way in which percutaneous absorption is calculated. Rat skin showed consistently to be more permeable than human skin. However, the difference between human and rat skin does not show a consistent pattern between chemicals hampering prediction of human percutaneous absorption. To increase predictive value of in-vitro and animal models, the influence of experimental factors on the percutaneous absorption should be systematically investigated by comparison with human in-vivo data, resulting in more prescriptive guideline

Determination of polyethylene glycols of different molecular weight in the stratum corneum

We developed a sensitive method for determination of polyethylene glycols (PEGs) of different molecular weight (MW) in the human stratum corneum (SC) obtained by tape stripping. The analysis is based on derivatization with pentafluoropropionic anhydride (PFPA) and gas chromatography-electron capture detection (GC-ECD). The identification and quantification of PEGs was done using individual oligomers. The method showed to be suitable for studying permeability in normal and impaired skin with respect to MW in the range of 150-600 Da. (C) 2004 Elsevier B.V. All rights reserve