No description available.

The prevalence of allergic diseases, including atopic dermatitis (AD; also known as atopic eczema), food allergy, hay fever, asthma, atopic eye disease and eosinophilic eosophagitis has increased dramatically in the developed world and in urbanised parts of the developing world over the past several decades. Atopic dermatitis is the most common chronic inflammatory disease of children, affecting 15-20% of children in the US and Europe. In many cases, infantile AD is associated with significant allergies to common foods such as peanut, hen’s egg and cow’s milk. Atopic dermatitis is followed in approximately 50% of cases by development of asthma and in 70%, hay fever in later childhood. The clustering of these conditions that often occurs in sequence has been termed the ‘atopic march’. The basis for the remarkable increase in the prevalence of these diseases is not well understood. For most of the latter half of the 20th Century the pathogenesis of atopic dermatitis was assumed to be primarily due to immune dysregulation. In the first decade of the 21st century, however, several lines of evidence emerged that placed the epithelial barrier as a central player in the pathogenesis of AD and of atopic disease in general. Several key discoveries that contributed to this change in understanding are included in the collection of publications presented for this DSc submission. The publications can be broadly grouped into studies on single gene disorders, their relevance to complex disease, subphenotyping of complex disease, mechanistic work and finally, some early translational approaches.

No description available.

The nail plate is a thick, tightly bound structure that protects the underlying nail bed from water loss, physical abrasion and infections. Despite its barrier properties, organisms are capable of traversing across and around the plate causing infection to the nail unit. Nail disease represents a time and cost intensive problem for the healthcare industry, with current topical and systemic treatment methods failing to stop the rise in incidence. Physical poration of the nail plate is discussed here with the first use of a femtosecond pulsed, fibre optic delivered, visible-light laser for drilling. Optical, Scanning Electron (SEM) and Atomic Force (AFM) microscopies were used to characterise the physical appearance of the nail plate before drilling. In addition, Fourier Transform Infrared (FTIR) and Raman spectroscopies were employed to investigate variation in the chemical structure of the nail plate across its thickness. Poration of the nail plate was facilitated using a dye to increase absorption of the laser radiation. Pores were drilled to various depths and widths by varying the amplitude of light pulses and exposure time. Incorporation of an optical chopper into the setup reduced thermal damage to the surrounding nail tissue. The geometry of pores, and the damage to the tissue surrounding them, was characterised with optical, electron and confocal microscopies. A novel technique to measure thermal damage surrounding the pore was developed. An empirical relationship between the Raman scattering and the temperature was established for nail pieces heat-treated at specific temperatures. This relationship was used to create temperature maps across porated areas. It was revealed the centre of pores were drilled by plasma-mediated poration, whilst thermal effects were responsible for removing material around the edges and damage to the remaining tissue. Verification of drilling as a suitable technique to reduce the resistance of the nail to topical delivery, was demonstrated with the delivery of caffeine across nail samples. Poration through the entirety of the plate effectively circumvented the barrier provided by an intact, untreated sample. Partial poration reduced the lag time for diffusion across the plate thus speeding up the drug delivery process.

Diverse pharmacological activities and the solid clinical performance of Chinese herbal medicines have attracted worldwide attention in terms of its modernization. Here, a hexaherbal Chinese formula (HHCF) for treating atopic dermatitis (AD) topically has been studied from chemical and biological perspectives. The HHCF comprises the rootstock of Scutellaria baicalensis Georgi (SCU), Rheum tanguticum Maxim. Ex Balf. (RHE), Sophora flavescens Aiton (SOP); the root bark of Dictamnus dasycarpus Turcz. (DIC); the bark of Phellodendron chinense C.K. Schneid. (PHE) and the fruit of Kochia scoparia (L.) Schrad. (KOC). In this thesis the chemical composition of the HHCF has been profiled and characterized using liquid-chromatography (LC) coupled with triple quadruple mass spectrometry (MS). 68 chemical compounds including alkaloids, anthraquinones, coumarins, flavonoids, naphthalene derivatives, phenylbutanone glucosides, phenolic acids, pterocarpans, stilbenes and tannins were putatively identified in the LC-MS profile of the HHCF based on mass measurement and characteristic fragment ions. The source(s) of these chemical compounds has been analyzed using the developed EXCEL template and PHE, RHE and SOP contributed the largest number of chemical compounds identified in the HHCF, while KOC seems to contribute very little. To evaluate the anti-inflammatory effects of the HHCF for treating AD/skin inflammation, the thymus and activation-regulated chemokine (CCL17), Prostaglandin E2 (PGE2), IL-8, IL-6 and hyaluronidase inhibitory effects were studies in vitro. Results showed that the HHCF inhibited hyaluronidase activity, TNF-α- plus IFN--induced CCL17 production in spontaneously immortalized human epidermal keratinocytes (HaCaT) and IL-1β-induced PGE2 in human fibroblasts with no effects on IL-8 and IL- 6. Among the chemical compounds characterized in LC-MS profile of the HHCF, multivariate regression models indicated the major contributor to the CCL17 inhibition were berberine, catechin dimers, gallic acid, galloylglucose, 4-(4'-hydroxylphenyl)-2- butanone 4'-O-β-D-glucoside, pyrogallol and resveratrol 4'-O-β-D-(6''-O-galloyl) glucoside. The effects of the HHCF against other pathogenesis-related targets need to be further study to ascertain its therapeutic efficacy against AD.

Studies have shown that capacitance sensors can be used for skin hydration imaging, surface analysis and skin micro relief measurements. In this report, development of a hardware measurement instrument and accompanying software that was made is discussed. Work then focussed on stratum corneum (SC) dynamic water concentration measurements using the capacitance sensor. To further validate the measurement results, the capacitance sensors SC surface hydration results are compared with the optoAthermal transient emission radiometry (OTTER) and transA epidermal water loss (TEWL) results measured by using the condenserAchamber TEWL method. To achieve the aim of this project, a handAheld probe, based on the FingerPrint Card area sensor development kit (FPCASMD 5410, FPCAAMD 6410 and then on the FUJITSU MBFA200), has been developed and used in this research. The development kit contains an array area sensor chip, a processor board and a serial/USB connecting cable for connecting to a PC. Dedicated JAVA, C++ and Mathworks MatLab programs have also been developed, which can capture the images, process the images, perform grayscale value calculation and display the images. A secondary program was developed in MatLab that allows extraction of data from raw image files created by the sensor. These data are then processed to show mathematical calculations and image profiling of the subject skin site. Additionally, the MBFA200 sensor is able to record live video files of the skin. The precision of the resulting data is analysed and multiple experiments are conducted to test the viability and usage of the capacitance sensor in different areas of research such as skin hydration, occlusion, depilation and scar measurement. Further test were also conducted on a multitude of hydrated surfaces both live an nonAlive.

The aim of this study is to develop new data analysis techniques and new measurement methodologies for skin hydration and solvent penetration measurements by using Opto-Thermal Transient Emission Radiometry (OTTER), AquaFlux and capacitive contact imaging based on Fingerprint sensor, three novel technologies developed by our research group. This research work is divided into three aspects: the theoretical work, the experimental work and the portable opto-thermal radiometry hardware design work. In the theoretical work, a) an effective image retrieval method based on Gabor wavelet transform has been developed, the results show that it is particularly useful for retrieving the grayscale capacitive skin images; b) an algorithm based on Grey Level Co-occurrence Matrix (GLCM) has been developed to analyze the grayscale capacitive skin images; c) a comparison study of Gabor wavelet transform, Grey level co-occurrence matrix (GLCM) and Principal Component Analysis (PCA) has been conducted in order to understand the performance of each algorithm, and to find out which algorithm is suitable for what type of images. In the opto-thermal radiometry hardware design work, a new, low cost, portable opto-thermal radiometry instrument, based on a broadband Infrared emitter and a room temperature PbS detector, has been designed and developed. The results show that it can work on any unprepared sample surfaces. In the experimental work, various in-vivo and in-vitro measurements were performed in order to study skin hydration and solvent penetration through skin and membranes. The results show that, combined with tape stripping, capacitive skin imaging can be a powerful tool for skin hydration, skin texture and solvent penetration measurements. The effect of three different parameters of Fingerprint sensor and its detection depth are also studied. The outcomes of this work have provided a better understanding for skin hydration and solvent penetration measurements and have generated several publications.

XP is considered a disease of failed repair of direct UVR-induced DNA photoproducts, leading to severe sunburn, extremely high rates of skin cancer, and death in young adulthood from complications relating to malignancy and neurodegeneration. Most experiments in the literature on XP cells, both for diagnosis and interpretation of photobiological processes, have used non-solar UVC radiation. Discernable differences in clinical phenotype have emerged from long-term follow-up of XP patients in the UK National XP clinic. The development of a sunburn severity score revealed that XP-C, XP-E and XP-V patients have normal sunburn reactions; a cohort of milder XP-A patients has been identified, arising from a likely founder mutation yielding less than 5% read-through of normal XPA protein. Deep phenotyping, including the development of ocular and neurological severity scores, has resulted in precise correlation of XP phenotype with the causal mutation, enabling the development of personalized prognostic advice for XP patients worldwide. Based on XP phenotype patterns, molecular experiments were conducted on skin fibroblasts from a range of XP complementation groups using environmentally relevant 385nm UVA-1 compared with 254nm UVC. UVA-1 was a more effective inducer of MMP mRNA and protein than UVC, by a mechanism independent of CPD. MMP upregulation was proportional with ROS generation, and this effect was attenuated when vitamin E was added to cell culture, providing indirect evidence that UVA-1-induced ROS was the main cause of MMP upregulation. The effects of UVA in XP literature have been largely ignored; studies here highlight that XP is a disease of impaired defenses against direct and indirect UVR-induced damage, which may explain sunburn, photoageing, skin cancer and neurological phenotype. These studies demonstrate the importance of translational research in this rare genetic disease. Photoprotection from solar-UVA, together with antioxidants, may provide a future gold standard for photoageing in the general population.

Solar radiation has numerous effects on the skin. Some are beneficial, however the majority are negative and contribute to development of skin cancer. Most studies have focused on ultra violet radiation (UVR ~290-400nm), however there is growing evidence to suggest that visible light (400-700nm) also causes skin damage. The main way of preventing solar damage is with the use of sunscreens, however these absorb in the UVR region with poor protection in the UVA/visible boundary waveband. There is growing evidence to suggest that synthetic UVR filters damage fragile marine environments, causing bleaching of corals and hormonal changes in fish. There is also evidence that some filters may damage human health, acting as exogenous oestrogens and inducing oxidative stress. The aim of this thesis was to assess biomarkers of skin damage with a range of in vitro and in vivo endpoints: DNA photodamage, inflammation/ immunoregulation, photoageing, oxidative stress and pigmentation. The focus was on broadband solar simulated UVR and its boundary with visible radiation (385-405nm). It was determined whether current sunscreen formulations provided adequate protection in this region, and if the addition of a new synthetic filter, could improve photoprotection. Furthermore, the ability of naturally occurring marine UVR filters, mycosporine-like amino acids (MAAs) was assessed, with a view to the development of a new generation of biocompatible alternatives to eco-toxic synthetic UVR filters. The results demonstrate that there is substantial damage in the UVR/visible boundary region for all biomarkers tested, and sunscreens using currently available filters do not provide sufficient protection; however the addition of the new filter significantly improved the protection offered. The MAA provided significant protection against all endpoints induced by solar simulated UVR. Furthermore, it demonstrated anti-oxidant capacity when added post UVR exposure. These results demonstrate that further investigation into the effects of visible radiation on the skin is required and the importance of improving sunscreens from an efficacy and environmental standpoint.

Epidermolysis bullosa (EB) is a group of inherited mechanobullous disorders characterised by trauma induced blistering. One of the most severe subtypes is recessive dystrophic epidermolysis bullosa (RDEB). RDEB is due to loss of function mutations in the gene encoding type VII collagen (COL7A1), one of the main constituents of anchoring fibrils anchoring the basement membrane to the underlying dermis. There is no cure for this devastating condition although promising pre-clinical studies for strategies using genetic correction, protein replacement, cell therapy or drug therapies are underway. Reconstitution of COL7A1 expression in both keratinocyte and fibroblast cell populations has been demonstrated using ex vivo gene therapy and hypothesised to lead to new anchoring fibril formation and amelioration of disease phenotype. Feasibility of this approach had been demonstrated in pre-clinical studies using a retroviral vector, and this work details the development of a phase 1 clinical trial to graft an autologous gene corrected skin equivalent graft. Detailed analysis of a cohort of adult patients with RDEB was performed in order to identify suitable trial candidates. In addition, an alternative strategy using a lentiviral vector encoding codon-optimised COL7A1 developed in order to transduce fibroblasts to be administered intradermally was developed. Expression and secretion of full-length de novo C7 was confirmed, with transduced cells exhibiting increased levels of protein expression despite only modest transduction efficiencies. This work details the journey and obstacles encountered in developing gene therapy clinical trials for RDEB, both through the development of a phase 1 study for an autologous gene corrected skin equivalent graft as well as a phase I study of intradermal autologous gene corrected fibroblasts.