Munich atopy prediction study (MAPS): protocol for a prospective birth cohort addressing clinical and molecular risk factors for atopic dermatitis in early childhood.

INTRODUCTION: The pathogenesis of atopic diseases is highly complex, and the exact mechanisms leading to atopic dermatitis (AD) onset in infants remain mostly enigmatic. In addition to an interdependent network of components of skin development in young age and skin barrier dysfunction underlying AD development that is only partially understood, a complex interplay between environmental factors and lifestyle habits with skin barrier and immune dysregulation is suspected to contribute to AD onset. This study aims to comprehensively evaluate individual microbiome and immune responses in the context of environmental determinants related the risk of developing AD in the first 4 years of a child's life. METHODS AND ANALYSES: The 'Munich Atopic Prediction Study' is a comprehensive clinical and biological investigation of a prospective birth cohort from Munich, Germany. Information on pregnancy, child development, environmental factors, parental exposures to potential allergens and acute or chronic diseases of children and parents are collected by questionnaires together with a meticulous clinical examination by trained dermatologists focusing on allergies, skin health, and in particular signs of AD at 2 months after birth and then every 6 months. In addition, skin barrier functions are assessed through cutometry, corneometry and transepidermal water loss at every visit. These measurements are completed with allergy diagnostics and extensive microbiome analyses from stool and skin swabs as well as transcriptome analyses using skin microbiopsies.The aim is to assess the relevance of different known and yet unknown risk factors of AD onset and exacerbations in infants and to identify possible accessible and robust biomarkers. ETHICS AND DISSEMINATION: The study is approved by the Ethical Committee of the Medical Faculty of the Technical University of Munich (reference 334/16S). All relevant study results will be presented at national and international conferences and in peer-reviewed journals.

Pre-digest of unprotected DNA by Benzonase improves the representation of living skin bacteria and efficiently depletes host DNA.

BACKGROUND: The identification of microbiota based on next-generation sequencing (NGS) of extracted DNA has drastically improved our understanding of the role of microbial communities in health and disease. However, DNA-based microbiome analysis cannot per se differentiate between living and dead microorganisms. In environments such as the skin, host defense mechanisms including antimicrobial peptides and low cutaneous pH result in a high microbial turnover, likely resulting in high numbers of dead cells present and releasing substantial amounts of microbial DNA. NGS analyses may thus lead to inaccurate estimations of microbiome structures and consequently functional capacities. RESULTS: We investigated in this study the feasibility of a Benzonase-based approach (BDA) to pre-digest unprotected DNA, i.e., of dead microbial cells, as a method to overcome these limitations, thus offering a more accurate assessment of the living microbiome. A skin mock community as well as skin microbiome samples were analyzed using 16S rRNA gene sequencing and metagenomics sequencing after DNA extraction with and without a Benzonase digest to assess bacterial diversity patterns. The BDA method resulted in less reads from dead bacteria both in the skin mock community and skin swabs spiked with either heat-inactivated bacteria or bacterial-free DNA. This approach also efficiently depleted host DNA reads in samples with high human-to-microbial DNA ratios, with no obvious impact on the microbiome profile. We further observed that low biomass samples generate an α-diversity bias when the bacterial load is lower than 105 CFU and that Benzonase digest is not sufficient to overcome this bias. CONCLUSIONS: The BDA approach enables both a better assessment of the living microbiota and depletion of host DNA reads. Video abstract.

Therapeutisches Management bei Vitiligo.

Vitiligo ist eine erworbene Hauterkrankung, an der weltweit 0,5 % der Bevölkerung erkranken und die eine große Herausforderung in der dermatologischen Versorgung darstellt. Die Erkrankung geht für Betroffene oftmals aufgrund der fleckigen Depigmentierung mit einer kosmetischen Entstellung und großem Leidensdruck einher. Pathophysiologisch werden als Hauptursachen für den Verlust funktionierender Melanozyten eine genetische Prädisposition, autoimmune Mechanismen und oxidativer Stress angesehen. Vorgestellt werden die Therapieempfehlungen der europäischen Leitlinie in Ergänzung mit Empfehlungen aus aktuellen Übersichtsarbeiten zu Vitiligo. Bisherige therapeutische Optionen greifen auf drei Wegen: (1.) Regulation der Autoimmunantwort mit topischen und systemischen immunmodulierenden Pharmaka (Kortikosteroide und Calcineurininhibitoren), (2.) Reduktion des melanozytären, oxidativen Stress mittels topischer und systemischer Antioxidantien sowie (3.) Aktivierung der Melanozytenregeneration durch Phototherapie (v. a. UVB) und Transplantation von pigmentierten Zellen. Darüber hinaus sollten dem Patienten Techniken zur Camouflage angeboten werden. Nach erfolgreicher Repigmentierung ist eine Rezidivprophylaxe mit Calcineurininhibitoren sinnvoll. Kombinationstherapien oben genannter Therapieansätze werden generell als erfolgreicher angesehen als Monotherapien. Auch ist ein möglichst früher Therapiebeginn prognostisch günstig. Mit Hilfe der genannten Therapieansätze kann es gelingen das Fortschreiten der Erkrankung aufzuhalten, depigmentierte Herde zu stabilisieren und eine Repigmentierung zu erreichen. Nur in Ausnahmefällen kommt eine dauerhafte Depigmentierung in Frage. Weiterreichende Erkenntnisse zur Pathogenese der Erkrankung lassen auf neue Therapieansätze hoffen.

Therapeutic management of vitiligo.

Affecting 0.5 % of the world's population, vitiligo is an acquired skin disorder that poses major challenges in terms of dermatological care. Characterized by patchy depigmentation, the disease is frequently associated with cosmetic disfigurement and considerable psychological distress. The primary pathophysiological causes for the loss of functional melanocytes are thought to include genetic predisposition, autoimmune mechanisms, and oxidative stress. The present article highlights treatment recommendations contained in the European guidelines as well as those provided by recent reviews on vitiligo. Current therapeutic options are based on three approaches: (1) Regulation of the autoimmune response using topical and systemic immunomodulatory agents (corticosteroids and calcineurin inhibitors); (2) decrease in oxidative stress in melanocytes by means of topical and systemic antioxidants; and (3) activation of melanocyte regeneration using phototherapy (UVB in particular) and transplantation of pigment cells. In addition, patients should be educated in techniques for cosmetic camouflage. Following successful repigmentation, application of calcineurin inhibitors is recommended to prevent recurrences. Combination therapies of the aforementioned approaches are generally considered to be more successful than monotherapies. Early initiation of treatment is associated with a more favorable prognosis. Using the above treatment options, it may be possible to halt disease progression, stabilize depigmented lesions, and achieve repigmentation. Only in exceptional cases should permanent depigmentation be considered as a possible option. New insights into the pathogenesis of vitiligo will likely give rise to novel therapeutic approaches.