Background and Aims: The Pharmacovigilance Risk Assessment Committee (PRAC) proposed measures to address severe side effects linked to Janus kinase inhibitors (JAKi) in immune-mediated inflammatory... Show moreBackground and Aims: The Pharmacovigilance Risk Assessment Committee (PRAC) proposed measures to address severe side effects linked to Janus kinase inhibitors (JAKi) in immune-mediated inflammatory diseases (IMID). Use of these medications in individuals aged 65 and older, those at high cardiovascular risk, active or former long-term smokers, and those with increased cancer risk should be considered only if no alternatives exist. Caution is advised when administering JAKi to patients at risk of venous thromboembolism. We aim to implement recommendations from regulatory guidelines based on areas of uncertainty identified. Methods: A two-round modified Research and Development/University of California Los Angeles appropriateness methodology study was conducted. A panel of 21 gastroenterologists, dermatologists and rheumatologists used a 9-point Likert scale to rate the appropriateness of administering a JAKi for each proposed clinical scenario. Scores for appropriateness were categorized as appropriate, uncertain, or inappropriate. Two rounds were performed, each with online surveys and a virtual meeting to enable discussion and rating of each best practice. Results: Round 1 involved participants rating JAKi appropriateness and suggesting descriptors to reduce uncertainty. Survey results were discussed in a virtual meeting, identifying areas of disagreement. In round 2, participants rated their agreement with descriptors from round 1, and the level of uncertainty and disagreement reduced. Age flexibility is recommended in the absence of other risk factors. Active counseling on modifiable risks (e.g., overweight, mild hyperlipidemia and hypertension) and smoking cessation is advised. Uncertainty persists regarding cancer risk due to various factors. Conclusions: We outlined regulatory guidance without a personalized evaluation of the patient's risk profile might lead to uncertainty and become an arid technicality. Therefore, we identified gaps and implemented PRAC recommendations to help health professionals in clinical practice. Show less
Barrier function is the natural role of the skin. The lipid matrix present in the outermost layer of the skin, the stratum corneum is important for this function. Barrier impairment and altered... Show moreBarrier function is the natural role of the skin. The lipid matrix present in the outermost layer of the skin, the stratum corneum is important for this function. Barrier impairment and altered lipid composition are observed in several inflammatory skin diseases including atopic dermatitis and psoriasis. However, the relationship between the lipid properties and barrier function is not comprehended.In this project, a lipid model was prepared from synthetic lipids that closely resemble the stratum corneum lipid composition and organization. Subsequently, diseased skin models were developed to mimic various abnormalities in lipid composition observed in atopic dermatitis patients’ skin. Biophysical methods were used to monitor the changes in lipid organization in these models. Diffusion studies and trans-epidermal water loss measurements were performed to monitor the barrier function. This allowed the determination of the changes in lipid properties that were most instrumental in reducing the lipid barrier.This thesis further describes the use of simple skin lipid model membranes incorporating fewer components to provide a detailed insight into the relationship between lipid composition, lipid organization, and the skin barrier. The information gained in this project offers the opportunity to develop a new generation of formulations to treat these patients. Show less
In this thesis, a new approach for rational drug development in inflammatory skin disease was described by focusing on three important cornerstones: I) developing skin inflammation models for early... Show moreIn this thesis, a new approach for rational drug development in inflammatory skin disease was described by focusing on three important cornerstones: I) developing skin inflammation models for early phase proof-of-pharmacology, II) integrating objective clinical endpoints and III) profiling disease in a multimodal fashion to more thoroughly evaluate drug effects. The results of this thesis show that integration of this approach in a clinical development program can directly influence the next steps in clinical development of the drug candidate. While each new drug needs a tailored approach, these general aspects need to be considered when designing dermatological drug development programs. This will lead to a more rational, efficient and less expensive way of dermatological drug development. Show less
The human body is colonized by microorganisms, collectively referred to as the human microbiota. Microbiota disturbance has been associated with a wide range of diseases and is the focus of many... Show moreThe human body is colonized by microorganisms, collectively referred to as the human microbiota. Microbiota disturbance has been associated with a wide range of diseases and is the focus of many research initiatives. The most widely used approach is based on sequencing of the 16S rRNA gene. This method can also be very valuable for clinical microbiology as it enables identification of a theoretically unlimited number of bacteria present in a specimen and permits (semi)quantitative information about the composition of a microbial community. In this thesis we investigated whether 16S rRNA gene profiling would have added value for direct diagnostics and/or as an indirect tool for evaluating cheaper diagnostic tests or evaluating treatments. The studies in this thesis were focused on respiratory tract infections, bacterial vaginosis, atopic dermatitis or male genital lichen sclerosus. The main challenge of 16S rRNA gene profiling is the clinical interpretation of relative abundance of the identified bacteria in clinical specimens. More clinical studies with appropriate control groups are needed to define and validate clinically relevant cut-off values, to measure microbiota variability over time and to determine microbial phenotypes. The clinical value of 16S rRNA gene profiling will probably become clear in the forthcoming years. Show less
The skin is our natural barrier and lipids are a key part of this barrier. In the outer skin layer, the stratum corneum (SC), lipids form a densely organized structure dependent on the composition... Show moreThe skin is our natural barrier and lipids are a key part of this barrier. In the outer skin layer, the stratum corneum (SC), lipids form a densely organized structure dependent on the composition of these lipids. Multiple skin diseases are characterized by alterations in SC lipid composition. These alterations are related to pathological barrier defects. This thesis describes the next steps towards a treatment modifying the lipid composition and thereby restoring this barrier. We developed a novel method to quantify a key SC lipid group called ceramides. This method was applied to compare SC regeneration of skin models to healthy volunteers. Regeneration in such an ex vivo skin model proved to be a potent model for formulation development. Ensuing, a clinical study was performed to determine the mechanistic effects of a formulation on barrier repair in healthy skin. The results warranted follow up analysis of the formulation in atopic dermatitis patients. This thesis also describes a detailed analysis of the ceramide fraction that is covalently attached to the cells in the SC. It was shown that a selected group of ceramides becomes bound. Further analysis showed that this group of ceramides was also affected in atopic dermatitis patients SC. Show less
Helder, R.W.J.; Boiten, W.A.; Dijk, R. van; Gooris, G.S.; El Ghalbzouri, A.; Bouwstra, J.A. 2019
Full thickness models (FTMs) are 3D-cultured human skin models that mimic many aspects of native human skin (NHS). However, their stratum corneum (SC) lipid composition differs from NHS causing a... Show moreFull thickness models (FTMs) are 3D-cultured human skin models that mimic many aspects of native human skin (NHS). However, their stratum corneum (SC) lipid composition differs from NHS causing a reduced skin barrier. The most pronounced differences in lipid composition are a reduction in lipid chain length and increased monounsaturated lipids. The liver-X-receptor (LXR) activates the monounsaturated lipid synthesis via stearoyl-CoA desaturase-1 (SCD-1). Therefore, the aim was to improve the SC lipid synthesis of FTMs by LXR deactivation. This was achieved by supplementing culture medium with LXR antagonist GSK2033. LXR agonist T0901317 was added for comparison. Subsequently, epidermal morphogenesis, lipid composition, lipid organization and the barrier functionality of these FTMs were assessed. We demonstrate that LXR deactivation resulted in a lipid composition with increased overall chain lengths and reduced levels of monounsaturation, whereas LXR activation increased the amount of monounsaturated lipids and led to a reduction in the overall chain length. However, these changes did not affect the barrier functionality. In conclusion, LXR deactivation led to the development of FTMs with improved lipid properties, which mimic the lipid composition of NHS more closely. These novel findings may contribute to design interventions to normalize SC lipid composition of atopic dermatitis patients. Show less
Danso, M.; Boiten, W.; Drongelen, V. van; Meijling, K.G.; Gooris, G.; Ghalbzouri, A. el; ... ; Bouwstra, J. 2017
The studies in this thesis describes the barrier defects in Atopic Dermatitis (AD) skin and various techniques to develop AD Human Skin Equivalents (HSEs) which can be used to better... Show more The studies in this thesis describes the barrier defects in Atopic Dermatitis (AD) skin and various techniques to develop AD Human Skin Equivalents (HSEs) which can be used to better understand the role of several factors in the pathogenesis of AD skin. The results described show that Inflammation plays a pivotal role in the development of epidermal and SC features of AD skin and that AD epidermal features can be maintained in vitro when AD skin biopsies are used to generate explant-HSEs. These AD-HSEs can also serve as a tool to screen potential therapeutics for AD and skin barrier repair. However, limitations exist in the complexity and full representation of all possible factors known to influence the development of AD e.g. FLG mutations, other aspects of inflammatory micro-environment, microbe colonization etc. Show less
Drongelen, V. van; Danso, M.O.; Out, J.J.; Mulder, A.; Lavrijsen, A.P.M.; Bouwstra, J.A.; Ghalbzouri, A. el 2015
Atopic Dermatitis (AD) is a frequent occurring inflammatory skin disease causing physical discomfort, social embarrassment and stress. This skin disease is characterized by decreased skin barrier... Show moreAtopic Dermatitis (AD) is a frequent occurring inflammatory skin disease causing physical discomfort, social embarrassment and stress. This skin disease is characterized by decreased skin barrier function and various other epidermal changes, as well as immunological changes. A decreased skin barrier function allows environmental factors such as allergens and pathogens to penetrate through the skin and evoke an immunological response, which in turn may negatively affect the skin barrier function. The skin barrier is composed of cornified keratinocytes, extracellular lipids and multiple proteins, including filaggrin. The discovery of mutations in the filaggrin gene as a major risk factor for development of AD has intensified research on this protein and its role in AD development, but its exact role in AD is still not clarified. This thesis describes the development of several reconstructed human skin equivalents (HSEs) which recapitulate various characteristics of AD. They display for example reduced filaggrin expression or alterations in epidermal characteristics due to the presence of AD-related inflammatory cytokines. These HSEs are a powerful tool that in the future might be used for screening purposes and/or development of new therapies for this life disabling skin disease. Show less
UVA 1 therapy is a relatively new form of light therapy for atopic dermatitis. We describe that after 4 weeks of UVA-1 patients were better capable to maintain clinical improvement than after 3... Show moreUVA 1 therapy is a relatively new form of light therapy for atopic dermatitis. We describe that after 4 weeks of UVA-1 patients were better capable to maintain clinical improvement than after 3 weeks of therapy. Furthermore, UVA 1 therapy proved to be better than placebo therapy in patients with dyshidrotic eczema. Also, we described the favorable effect of UVA 1 therapy in chronic, generalized lichen ruber planus. Because of deep penetration of UVA 1, it could not only influence dermal inflammatory infiltrates in T-cell mediated diseases mentioned above, but also reach circulating activated B-cells in dermal capillaries in SLE. We investigated the effect of 6 and 12 J/cm2 UVA 1 in SLE patients, in a double-blinded, placebo-controlled, cross over study. Three weeks of 12 J/cm2 resulted in improved disease activity and proved to be more effective than placebo. Furthermore, a decrease of auto-antibody titers was observed in several patients. In vitro we showed that 40% of UVA 1 reached the dermis and increasing numbers of PBMCs died after rising doses of UVA-1. Also, immunoglobulin production by activated B cells decreased after increasing doses of UVA 1. It would be interesting to investigate UVA 1 therapy for other auto immune diseases. Show less
