Atopic dermatitis, AD (synonym eczema) is a chronic inflammatory skin disease. It affects between 10 to 20% of children and 1 to 3% of adults worldwide. It is an important cause of morbidity and is estimated to cost £465 million per annum to the UK. AD is part of a family of Th-2 driven diseases and is often the first of these atopic diseases to manifest. The development of AD is often followed by asthma and allergic rhinitis later in life (a phenomenon known as the ‘atopic march’). Up to 50% of moderate to severe AD cases have been associated with genetic mutations affecting the epidermal barrier protein filaggrin. Filaggrin aggregates keratin filaments during terminal keratinocyte differentiation, allowing normal epidermal stratification. The role of filaggrin in maintaining a functional skin barrier is further supported by a clinical study conducted by ourselves. This is the first clinical study on a European cohort (58 participants) which showed that FLG mutations were associated with experimentally demonstrable defects of skin barrier function (increased baseline transepidermal water loss), more so following exposure to a chemical irritant. However, the majority of patients with AD, especially the milder cases, do not have FLG mutations. Some of the wild-type patients in our study were noticed to have accumulation of the large filaggrin proprotein and a lack of filaggrin monomers, indicating defective proteolysis of profilaggrin into the functional monomers. Our study also found disproportionately raised protease inhibitory activities amongst the AD participants. This inappropriately raised protease inhibition may interfere with profilaggrin proteolysis, leading to the development of AD in some wild-type patients. Having demonstrated that deficiency of filaggrin monomers is associated with a defective skin barrier, we focused on the function of filaggrin in the skin and attempted to improve the skin barrier function. In addition to keratin aggregation, filaggrin constitutes the natural moisturizing factors in the epidermis following its natural breakdown into amino acids. We note that filaggrin is disproportionately rich in amino acid histidine, implying that this amino acid may have a particular significance in maintaining a functional epidermal barrier. Using an in-house skin-equivalent model, we have shown that by increasing the histidine content in the cell culture media, we could increase the expression of filaggrin monomers and reduce the penetration of a fluorescent dye into the skin-equivalents. The latter indicates improved barrier function. Finally, we conducted a pilot human study which showed that histidine, when applied to mechanically damaged skin in AD and healthy participants, was associated with a faster recovery of the skin barrier function. These studies suggest that histidine is of therapeutic benefits in AD. A histidine-based treatment may be developed as an alternative to current anti-inflammatory and immunosuppressive agents used to treat AD.

Aims and objectives: The research aims and objectives of this study were: Firstly to determine the positive effects and possible disadvantages of three types of barrier creams on skin barrier function by determining skin barrier function by measuring stratum corneum hydration transepidermal water loss (TEWL) and skin surface pH. Secondly to compare different racial skin types (African skin to Caucasian skin) by determining the effects of barrier cream on skin barrier function. Finally to compare the effect of the three different barrier creams on four different anatomical areas. Methods: Thirty eight non-smoking male test subjects took part in this study where three different types of barrier creams were tested on their arms and hands in a controlled laboratory environment. The thirty eight test subjects consisted of nineteen African and nineteen Caucasian test subjects. Three parameters were measured namely TEWL, stratum corneum hydration and pH condition of the skin. TEWL was measured using a Vapometer (Delfin Technology Ltd. Finland). The Multi probe Adapter system (MPA) (Courage and Khazaka, Germany) was used with a temperature and humidity sensor and with the following probes all from Courage and Khazaka, Germany: a Corneometer measuring skin hydration and a pH-Meter measuring skin surface pH. The measurements were repeated on each of the four sampling areas (forearm, wrist, back of hand and palm) with a reasonable time interval between each measurement. After the baseline measurement the barrier cream was applied by the researcher on the test subjects’ dominant arm. The long term effects were determined after the baseline measurement in intervals of 2 hours. Directly after each measurement the barrier cream was reapplied. Results: Gloves In A Bottle™ increased stratum corneum hydration, had no effect on TEWL and increased skin surface pH, whereas Reinol™ increased stratum corneum hydration and decreased TEWL and had no effect on pH values. Travabon™ decreased stratum corneum hydration and TEWL and had no effect on skin surface pH. The results indicated that there were significant differences between Caucasian and African test subjects with the use of barrier creams, because of the baseline differences and the reaction to barrier creams showed different results. There were also statistically significant differences in the four different anatomical areas where the barrier creams were applied. Conclusion: Barrier creams are beneficial in the workplace, although it should be taken into consideration that different ethnicities react differently to barrier creams under different workplace situations and therefore this should be taken into account when selecting a barrier cream. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013

Aims and objectives: The research aims and objectives of this study were: Firstly to determine the positive effects and possible disadvantages of three types of barrier creams on skin barrier function by determining skin barrier function by measuring stratum corneum hydration transepidermal water loss (TEWL) and skin surface pH. Secondly to compare different racial skin types (African skin to Caucasian skin) by determining the effects of barrier cream on skin barrier function. Finally to compare the effect of the three different barrier creams on four different anatomical areas. Methods: Thirty eight non-smoking male test subjects took part in this study where three different types of barrier creams were tested on their arms and hands in a controlled laboratory environment. The thirty eight test subjects consisted of nineteen African and nineteen Caucasian test subjects. Three parameters were measured namely TEWL, stratum corneum hydration and pH condition of the skin. TEWL was measured using a Vapometer (Delfin Technology Ltd. Finland). The Multi probe Adapter system (MPA) (Courage and Khazaka, Germany) was used with a temperature and humidity sensor and with the following probes all from Courage and Khazaka, Germany: a Corneometer measuring skin hydration and a pH-Meter measuring skin surface pH. The measurements were repeated on each of the four sampling areas (forearm, wrist, back of hand and palm) with a reasonable time interval between each measurement. After the baseline measurement the barrier cream was applied by the researcher on the test subjects’ dominant arm. The long term effects were determined after the baseline measurement in intervals of 2 hours. Directly after each measurement the barrier cream was reapplied. Results: Gloves In A Bottle™ increased stratum corneum hydration, had no effect on TEWL and increased skin surface pH, whereas Reinol™ increased stratum corneum hydration and decreased TEWL and had no effect on pH values. Travabon™ decreased stratum corneum hydration and TEWL and had no effect on skin surface pH. The results indicated that there were significant differences between Caucasian and African test subjects with the use of barrier creams, because of the baseline differences and the reaction to barrier creams showed different results. There were also statistically significant differences in the four different anatomical areas where the barrier creams were applied. Conclusion: Barrier creams are beneficial in the workplace, although it should be taken into consideration that different ethnicities react differently to barrier creams under different workplace situations and therefore this should be taken into account when selecting a barrier cream. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013

Des formes galéniques spécialement étudiées permettent l'administration topique d'un médicament ou d'un actif cosmétique afin d'obtenir un effet local ou une action systémique. Les excipients présents dans la formulation, comme les tensioactifs dans les solutions micellaires, émulsions, microémulsions, nanoémulsions, nanostructures, peuvent être alors des éléments influençant la pénétration et la perméation de l'actif. L'étude de leurs effets sur la barrière cutanée peut être utile afin de choisir au mieux les différents composés de la formulation. L'objectif de cette thèse a été d'étudier l'effet de différents tensioactifs (alkylpolyglucosides, lipoaminoacides, alcools gras éthoxylés et copolymères à blocs de type Poloxamer) en solution aqueuse sur la structure et la fonction barrière de la peau, grâce à des techniques d'infrarouge à transformée de Fourier, de calorimétrie différentielle à balayage, de mesure de la perte insensible en eau et de microscopie électronique à transmission. L'objectif spécifique de ce travail a porté sur l'étude de l'absorption cutanée ex vivo de trois principes actifs de lipophilie différente (caféine, kétoprofène et progestérone) à travers un modèle de peau animale co-traitée par différents tensioactifs. Plus spécifiquement, la pénétration de la progestérone au sein des différentes couches de la peau a été étudiée compte tenu de sa lipophilie élevée limitant son passage dans les couches cutanées plus hydrophiles. A l'issue de ces travaux, nous montrons que les tensioactifs peuvent exercer non seulement des effets sur l'organisation lamellaire des lipides intercornéocytaires mais aussi sur les cornéocytes du stratum corneum (SC). Par ailleurs, ces différents résultats ont permis de définir les structures chimiques des tensioactifs favorisant l'absorption cutanée de principes actifs. Les tensioactifs anioniques comportant une chaîne aliphatique de 12 carbones augmentent sélectivement la perméation cutanée de principes actifs hydrophiles et la pénétration de principes actifs lipophiles dans les tissus cutanés. La pénétration cutanée de principes actifs est étroitement corrélée à la taille des micelles de tensioactif susceptible de s'incorporer dans les espaces intercornéocytaires du SC. Enfin, la valeur de concentration micellaire critique est une propriété physico-chimique permettant d'expliquer en partie l'effet des tensioactifs sur leur perméabilité cutanée / Dosage forms specially designed allow the topical administration of drugs or cosmetic active ingredients to obtain a local effect or a systemic action. Excipients, such as surfactants in micellar solutions, emulsions, microemulsions, nanoemulsions, nanostructures can influence the drug penetration and permeation. Understanding their effects on skin barrier is helpful in the choice of surfactant. The aim of this thesis was to study the effect of different surfactants (alkylpolyglucosides, lipoaminoacids, ethoxylated fatty alcohol and copolymers blocks) in aqueous solution on the skin barrier structure and function, using techniques like infrared Fourier transform, differential scanning calorimetry, transepidermal water loss measurement and transmission electron microscopy. The specific aim of this work focused on the ex vivo cutaneous absorption of three drugs showing different lipophilicity (caffeine, ketoprofen and progesterone) through animal skin co-treated by different surfactants. More specifically, the penetration of progesterone in the different skin layers has been studied due to its high lipophilicity limiting its permeation in the most hydrophilic layers (viable epidermis and dermis). At the outset, we showed that surfactants could provide not only an effect on lamellar organization of intercorneocyte lipids but also on the corneocytes into the stratum corneum (SC). Moreover, these different results allowed to define surfactant chemical structure increasing drug cutaneous absorption. Anionic surfactant with a C12 chain length increased significantly cutaneous permeation of hydrophilic drug and penetration of lipophilic drug into cutaneous tissue. Drug penetration is correlated with micelle size allowed its incorporation into SC intercorneocyte spaces. Finally, the value of its critical micellar concentration is a physico-chemical properties allowed to partially explain the surfactant effect on their cutaneous permeability

Background: The differential effects of using topical oils for the prevention or treatment of baby dry skin on skin barrier function may contribute to the development of childhood atopic eczema. Prevalence of atopic eczema has increased from 5% of children aged 2 to 15 years in the 1940s, to approaching 30% more recently. This increase cannot be attributed to genetic changes. It is likely that increases stem from environmental factors, including the increased use of some inappropriately formulated commercial and natural baby skincare products. Midwives, health visitors and other maternity service health professionals, in the UK, routinely recommend the use of olive oil and sunflower oil for baby dry skin or massage, but the effect of these oils on newborn baby skin has not been studied. Aim: The aim of this research was to assess the feasibility and acceptability of testing the hypothesis that the regular application of sunflower oil, when compared to no oil or olive oil, had an effect on skin barrier function of newborn term babies. Study Design: A pilot, assessor-blinded, single centre, three-arm, randomised controlled trial, with nested qualitative component, underpinned by post-positivism. Methods: Quantitative methods were used to establish proof of concept that the use of topical oils had some effect on newborn baby skin barrier function, and to assess the feasibility of trial processes and parameters. Qualitative methods were used to explore the acceptability to parents of having a newborn baby participating in a randomised controlled trial, and trial design and procedures. The study was conducted in St. Mary’s hospital, a large teaching hospital in North West England. Data were collected between September 2013 and August 2014.The randomised controlled trial included 115 babies who were randomised to three groups: sunflower oil, olive oil and no oil, using a computer-generated varied size block randomisation with concealed allocation. Parents of babies randomised to the oil groups were blinded to which oil they were allocated. Data were collected using standardised case report forms for demographic and clinical observation data, weekly telephone questionnaires and a follow-up questionnaire, informed by previous baby skincare trials. The qualitative study encompassed semi-structured interviews, conducted within six months of birth. The sample was a subset of the trial participants, purposively sampled to incorporate a mix of treatment groups and positive and negative experiences derived from the follow-up questionnaire. Data also included two open-text questions from the follow-up questionnaire. Quantitative data were managed using IBM SPSS Statistics versions 20 and 22 and analysed descriptively. Qualitative data were managed in NVivo 10 and analysed using Framework Analysis. Results: The pilot study found that a definitive randomised controlled trial is not the optimal next step. A longitudinal observational study and further mechanistic work is recommended. Recruitment was challenging and loss to follow-up was higher than anticipated. Protocol adherence was reasonable and the study was acceptable to parents. Some statistically significant results were obtained, which must be interpreted with caution as the study was not powered to detect such a difference. These results showed that both oils may impede the development of the skin barrier function from birth; clinical importance of the results is not known. Conclusion: A longitudinal observational study is required, which maps the diagnosis of atopic eczema with environmental factors such as the use of baby skincare products from birth. Mechanistic work is also required to consider the optimal skincare formulation. As any intervention should do more good than harm, it would be wrong to support the recommendation of topical olive oil or sunflower oil for newborn baby dry skin or massage, based on the study data.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21804号 / 農博第2317号 / 新制||農||1065(附属図書館) / 学位論文||H31||N5176(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 菅原 達也, 教授 佐藤 健司, 教授 松井 徹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23940号 / 農博第2489号 / 新制||農||1090(附属図書館) / 学位論文||R4||N5375(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 菅原 達也, 教授 佐藤 健司, 教授 松井 徹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

No / Transmembrane pore formation is central to many biological processes such as ion transport, cell fusion, and viral infection. Furthermore, pore formation in the ceramide bilayers of the stratum corneum may be an important mechanism by which penetration enhancers such as dimethylsulfoxide (DMSO) weaken the barrier function of the skin. We have used the potential of mean constraint force (PMCF) method to calculate the free energy of pore formation in ceramide bilayers in both the innate gel phase and in the DMSO-induced fluidized state. Our simulations show that the fluid phase bilayers form archetypal water-filled hydrophilic pores similar to those observed in phospholipid bilayers. In contrast, the rigid gel-phase bilayers develop hydrophobic pores. At the relatively small pore diameters studied here, the hydrophobic pores are empty rather than filled with bulk water, suggesting that they do not compromise the barrier function of ceramide membranes. A phenomenological analysis suggests that these vapor pores are stable, below a critical radius, because the penalty of creating water-vapor and tail-vapor interfaces is lower than that of directly exposing the strongly hydrophobic tails to water. The PMCF free energy profile of the vapor pore supports this analysis. The simulations indicate that high DMSO concentrations drastically impair the barrier function of the skin by strongly reducing the free energy required for pore opening. / EPSRC

Moisturizers are used in various types of dry skin disorders, but also by people with healthy skin. It is not unusual that use of moisturizers is continued for weeks, months, or even years. A number of moisturizers have been shown to improve the skin barrier function, while others to deteriorate it, but the reason for observed effects remains unknown. Further understanding of the mechanism by which long-term treatment with moisturizers influences the skin barrier would have clinical implications, as barrier-deteriorating creams may enhance penetration of allergens or irritants and predispose to dry skin and eczema, while barrier-improving ones could reduce many problems. The present research combined non-invasive techniques with analyses of skin biopsies, allowing studies of the epidermis at molecular and cellular level. Test moisturizers were examined on healthy human volunteers for their effect on the skin barrier, with regard to such factors as pH, lipid type, and presence of a humectant, as well as complexity of the product. After a 7-week treatment with the moisturizers, changes in transepidermal water loss, skin capacitance, and susceptibility to an irritant indicated a modified skin barrier function. Moreover, the mRNA expression of several genes involved in the assembly, differentiation and desquamation of the stratum corneum, as well as lipid metabolism, was altered in the skin treated with one of the moisturizers, while the other moisturizer induced fewer changes. In conclusion, long-term use of moisturizers may strengthen the barrier function of the skin, but also deteriorate it and induce skin dryness. Moisturizers have also a significant impact on the skin biochemistry, detectable at molecular level. Since the type of influence is determined by the composition of a moisturizer, more careful selection of ingredients could help to design moisturizers generating a desired clinical effect, and to avoid ingredients with a negative impact on the skin.

Atopic dermatitis (AD), ichthyosis vulgaris (IV), and X-linked recessive ichthyosis (XLRI) are characterized by dry skin and impaired skin barrier. AD and IV are related to loss-of-function mutations in FLG (encoding filaggrin), whereas XLRI is caused by deletions or inactivating mutations in the steroid sulphatase gene (STS). Patients regularly use moisturizing creams, but little is known about the creams’ effects on the skin barrier. The present work combines objective scorings, non-invasive techniques, and molecular analyses of skin biopsies to characterize the skin in 57 patients with AD, IV, or XLRI, and in 14 healthy controls. Patients were classified according to their FLG and STS mutation status: AD with FLG+/+ (n = 14), AD with FLG+/– (n = 14), AD/IV with FLG–/– (n = 15), and XLRI with STS– (n = 14), as well as one man with a novel point mutation. Assessments were conducted at baseline and after four weeks of treatment with three different moisturizers applied to volar forearm skin. At baseline, dryness scoring and non-invasive assessments verified impaired skin barrier function in all patients. In patients with AD/IV, microarray analysis identified 300–3000 up- or downregulated mRNA transcripts involved in signalling pathways important for inflammation and barrier repair. The skin phenotype and number of altered transcripts were correlated with the FLG mutation status, with FLG–/– patients displaying the highest transepidermal water loss (TEWL) and the most altered transcript levels. In contrast, despite an equally dysfunctional skin barrier, only limited changes in mRNA transcripts occurred in XLRI patients. Treatment with moisturizers improved skin dryness similarly in all groups, but TEWL behaved differently: it decreased slightly in the AD/IV group and increased in the XLRI group, especially after urea treatment. Only minute effects on skin pH and mRNA expression were observed. In conclusion, FLG mutations elicit pro-inflammatory mechanisms probably aimed at restoring barrier competence. This does not occur in patients with XLRI, presumably because STS deficiency automatically increases the barrier thickness. Moisturizing treatment improves skin dryness in patients with AD, IV, or XLRI, but does not seem to normalize the altered epidermal gene expression profile in AD/IV patients.