Association between skin barrier development and early-onset atopic dermatitis: A longitudinal birth cohort study.

BACKGROUND: A diagnosis of atopic dermatitis (AD) is common during infancy; however, it is unclear whether differential skin barrier development defines this period and signals disease onset in predisposed individuals. OBJECTIVE: We sought to study (NCT03143504) and assess the feasibility of remote skin testing from birth to monitor skin barrier maturation and model association with an AD diagnosis by age 12 months. METHODS: Biophysical testing and infrared spectroscopy were conducted at the maternity ward and family home. Tape stripping collected samples for desquamatory protease and natural moisturizing factor analysis. The 4 common European filaggrin risk alleles were screened. RESULTS: A total of 128 infants completed the study, with 20% developing mild disease. Significant changes in permeability barrier function, desquamatory protease activity, and molecular composition assessed spectroscopically were observed longitudinally, but only subtle evidence of differential skin barrier development was noted between infant subgroups. Common filaggrin risk alleles were strongly associated with early-onset disease and conferred a significant reduction in natural moisturizing factor and water content by age 4 weeks. Accounting for a family history of atopy, these parameters alongside a greater lipid/protein ratio and reduced chymotrypsin-like activity at birth were associated with AD. Measured in ambient conditions, transepidermal water loss did not signal disease risk at any stage. CONCLUSIONS: Skin barrier dysfunction lacked an acquired modality but was considered proportional to cohort severity and suggests that a portfolio of tests used in a community setting has the potential to improve current AD risk evaluations from birth.

Characterisation of skin barrier defects in atopic dermatitis patients using Infrared Spectroscopy.

INTRODUCTION: Atopic dermatitis (AD) is characterised by skin barrier defects often measured by biophysical tools that observe stratum corneum (SC) functional properties. OBJECTIVE: To employ in vivo infrared spectroscopy alongside biophysical measurements to analyse changes in chemical composition of the SC in relation to AD severity. METHODS: We conducted an observational cross-sectional cohort study where attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy measurements were collected on the forearm alongside surface pH, capacitance, erythema and transepidermal water loss (TEWL) combined with tape stripping (STS) in a cohort of 75 participants; 55 AD patients stratified by phenotypic severity, compared to 20 healthy controls. Common filaggrin (FLG) variant alleles were genotyped. RESULTS: Reduced hydration, elevated TEWL and redness all associated with greater AD severity. Spectral analysis showed a reduction in 1465cm-1 (full width half maximum) and 1340 cm-1 peak areas indicative of less orthorhombic lipid ordering and reduced carboxylate functional groups that correlated with clinical severity (lipid structure r=-0.59, carboxylate peak area r=-0.50). CONCLUSION: ATR-FTIR spectroscopy is a suitable tool for the characterisation of structural skin barrier defects in AD and has potential as a clinical tool for directing individual treatments based on chemical structural deficiencies.

Enhancement of stratum corneum lipid structure improves skin barrier function and protects against irritation in adults with dry, eczema-prone skin.

BACKGROUND: The skin of patients with atopic dermatitis is characterized by abnormal stratum corneum lipid levels. Consequently, the lamellar matrices are disrupted and skin barrier function is diminished, increasing skin sensitivity to irritants and allergens. OBJECTIVES: To determine whether a cream containing ceramides, triglycerides and cholesterol in a multivesicular emulsion can reinforce the skin barrier and protect against skin irritation. METHODS: A randomized observer-blind intrapatient-controlled study in 34 adults with dry, eczema-prone skin was conducted. Each participant underwent 4 weeks of treatment with the test cream on one forearm and lower leg and a reference emollient cream on the other. Skin properties were determined before and after treatment. Lipid structure was assessed by Fourier-transform infrared spectroscopy using a novel interface. RESULTS: Skin barrier integrity was greater at sites treated with the test cream [effect size for area under the transepidermal water loss curve -162, 95% confidence interval (CI) -206 to -118]. Skin sensitivity to sodium lauryl sulfate was reduced (-0·5 points visual redness, 97·57% CI -1·00 to -0·25), as was transepidermal water loss (-15·3 g m-2 h-1 , 95% CI -20·3 to -10·4) compared with the reference. Sites treated with the test cream displayed enhanced lipid chain ordering, which was significantly associated with skin barrier integrity (r = 0·61). Compared with the reference, treatment with the test cream increased hydration (8·61 capacitance units, 95% CI 6·61-10·6) and decreased signs of dryness. CONCLUSIONS: The test cream facilitates skin barrier restoration and protects the skin from dryness and irritation. Compared with a commonly prescribed emollient in the UK, the test cream is highly suited to the management of dry, sensitive skin.

Different types of emollient cream exhibit diverse physiological effects on the skin barrier in adults with atopic dermatitis.

BACKGROUND: Eczema (atopic dermatitis; AD) is a very common itchy skin condition affecting 1 in 5 children and up to 1 in 10 adults worldwide. The skin of eczema sufferers is prone to redness, irritation and dryness because it does not form an effective barrier, i.e. the ability of the skin to stop irritants, allergens and microorganisms getting into the body. Skin barrier dysfunction is a hallmark of AD. The regular and liberal (600 g/week for an adult) use of emollients is recommended for all patients with eczema), even between episodes of itching and redness, to soften and soothe the skin. In England alone, almost 9 million prescriptions for emollient creams were issued in 2018, at a cost of over £50 million. Despite this widespread use, relatively little is known about how commonly prescribed emollient creams affect the skin's barrier, and thus the role of moisturizers in AD development and progression remains unclear. We set out to compare three different types of emollient cream and a no-treatment control. AIM: To compare the barrier-strengthening properties of a new moisturizer containing urea and glycerol (urea-glycerol cream; UGC), with those of a glycerol-containing moisturizer (glycerol cream; GC), a simple paraffin cream (PC) with no humectant, and a no-treatment control (NTC). METHODS: This was an observer-blinded prospective Phase 2 within-subject multilateral single-centre randomized controlled trial in adults with AD (Clinical Trials #NCT03901144). The intervention involved 4 weeks of treatment, twice daily, with the three products applied to one of four areas on the forearms the (the fourth area was the untreated control, randomized allocation). Skin properties [dryness, transepidermal water loss (TEWL), hydration and natural moisturizing factor (NMF) levels] were assessed before, during and after treatment to see what happened to the skin's barrier. The primary outcome was skin sensitivity to the irritant sodium lauryl sulfate (SLS) after treatment. We performed tests on the skin before and after treatment to see what happened to the skin's barrier. RESULTS: In total, 49 patients were randomized, completed treatment and included in the analysis. UGC significantly reduced the response to SLS as indicated by a reduction in TEWL compared with NTC (-9.0 g/m2 /h; 95% CI -12.56 to -5.49), with PC (-9.0 g/m2 /h; 95% CI -12.60 to -5.44) and with GC -4.2 g/m2 /h; 95% CI 7.76 to -0.63). Skin moisturization improved at sites treated with UGC compared with NTC and PC, and this was accompanied by concordant changes in dryness and NMF levels. Subgroup analysis suggested FLG-dependent enhancement of treatment effects. CONCLUSION: The study showed that not all emollient creams for eczema are equal. The simple paraffin-based emollient, which represents the most widely prescribed type of emollient cream in England, had no effect on the skin's barrier and reduced the skin's NMF. UGC markedly improved the skin's barrier and protected against irritation. GC performed better than PC, but not as well as UGC. UGC strengthened the skin barrier through a mechanism involving increased NMF levels in the skin, and imparted protection from SLS-induced irritation. By helping correct a major pathophysiological process, UGC has the potential to improve the long-term control of AD. The results show that different emollient creams have different effects on our skin, and only certain types have the ability to improve the skin's barrier and protect against irritants that trigger eczema.

Olive Oil, Sunflower Oil or no Oil for Baby Dry Skin or Massage: A Pilot, Assessor-blinded, Randomized Controlled Trial (the Oil in Baby SkincaRE [OBSeRvE] Study).

Topical oils on baby skin may contribute to development of childhood atopic eczema. A pilot, assessor-blinded, randomized controlled trial assessed feasibility of a definitive trial investigating their impact in neonates. One-hundred and fifteen healthy, full-term neonates were randomly assigned to olive oil, sunflower oil or no oil, twice daily for 4 weeks, stratified by family history of atopic eczema. We measured spectral profile of lipid lamellae, trans-epidermal water loss (TEWL), stratum corneum hydration and pH and recorded clinical observations, at baseline, and 4 weeks post-birth. Recruitment was challenging (recruitment 11.1%; retention 80%), protocol adherence reasonable (79-100%). Both oil groups had significantly improved hydration but significantly less improvement in lipid lamellae structure compared to the no oil group. There were no significant differences in TEWL, pH or erythema/skin scores. The study was not powered for clinical significance, but until further research is conducted, caution should be exercised when recommending oils for neonatal skin.

The Effect of an Emollient Containing Urea, Ceramide NP, and Lactate on Skin Barrier Structure and Function in Older People with Dry Skin.

Xerosis affects up to 75% of older people and develops as a result of a skin barrier defect. Emollients are widely used to treat xerosis; however, there is limited understanding of the differences between them and their effects on the skin barrier in older people. This study aimed to compare the effect of a commercially available emollient containing 5% urea, ceramide NP and lactate (test emollient) to an alternative emollient without these additives (control emollient) on the properties of the skin barrier in older people. Two cohorts of 21 volunteers aged >60 years with dry skin were recruited. The first applied the test emollient to one forearm and no treatment to the other for 28 days. The second compared the test emollient to the control emollient observing the same parameters. Effects on the skin barrier were determined by measuring skin barrier function, hydration, skin surface pH and by analysing Fourier transform infrared spectra before and after treatment. A third cohort of 6 young adults was recruited to investigate the effect of a single treatment with the test emollient on the molecular structure of the skin barrier at greater depths by employing the tape-stripping technique. The test emollient hydrated the skin to a significantly greater extent and for a longer period of time compared to the control emollient, an effect associated with a significant elevation of carboxylate groups (a marker of natural moisturizing factor content) within the stratum corneum. Furthermore, the test emollient imparted additional benefits to the structure and function of the skin barrier not exhibited by the control emollient. In conclusion, the test emollient addressed the pathological features of xerotic aged skin, supporting its use as first-line therapy for xerotic skin conditions in this population.

Comparing the Effect of a Twice-weekly Tacrolimus and Betamethasone Valerate Dose on the Subclinical Epidermal Barrier Defect in Atopic Dermatitis.

The proactive use of topical anti-inflammatory (TAI) therapy to address subclinical inflammation is an effective, contemporary clinical strategy for the management of atopic dermatitis (AD). The interaction of a proactive TAI dose with the subclinical epidermal barrier defect in AD is yet to be determined. A randomised, observer-blind, functional mechanistic study in 17 subjects with quiescent AD was performed to compare the effect of a twice-weekly dose of betamethasone valerate (0.1%) cream (BMVc), against tacrolimus (0.1%) ointment (TACo) on the biophysical and biological properties of the epidermal barrier. Application of BMVc preserved epidermal barrier function and stratum corneum (SC) integrity, but significantly elevated skin-surface pH with concomitant loss of SC cohesion. By contrast, TACo improved SC integrity, exerted an overall hydrating action, and significantly reduced caseinolytic and trypsin-like protease activity. The differential effects reported support the proactive use of TACo to promote reparation of the subclinical barrier defect in AD.

Maintenance of an Acidic Skin Surface with a Novel Zinc Lactobionate Emollient Preparation Improves Skin Barrier Function in Patients with Atopic Dermatitis.

INTRODUCTION: The skin of patients with atopic dermatitis (AD) is characterised by elevated pH. As a central homeostatic regulator, an increased pH accelerates desquamation and suppresses lipid processing, resulting in diminished skin barrier function. The aim of this study was to determine whether a novel zinc lactobionate emollient cream can strengthen the skin barrier by lowering skin surface pH. METHODS: A double-blind, forearm-controlled cohort study was undertaken in patients with AD. Participants applied the test cream to one forearm and a vehicle cream to the other (randomised allocation) twice daily for 56 days. Skin surface pH and barrier function (primary outcomes) were assessed at baseline and after 28 days and 56 days of treatment, amongst other tests. RESULTS: A total of 23 adults with AD completed the study. During and after treatment, a sustained difference in skin surface pH was observed between areas treated with the test cream and vehicle (4.50 ± 0.38 versus 5.25 ± 0.54, respectively, p < 0.0001). This was associated with significantly reduced transepidermal water loss (TEWL) on the test cream treated areas compared with control (9.71 ± 2.47 versus 11.20 ± 3.62 g/m2/h, p = 0.0005). Improvements in skin barrier integrity, skin sensitivity to sodium lauryl sulphate, skin hydration, and chymotrypsin-like protease activity were all observed at sites treated with the test cream compared with the control. CONCLUSION: Maintenance of an acidic skin surface pH and delivery of physiologic lipids are beneficial for skin health and may help improve AD control by reducing sensitivity to irritants and allergens.

Effect of olive and sunflower seed oil on the adult skin barrier: implications for neonatal skin care.

Natural oils are advocated and used throughout the world as part of neonatal skin care, but there is an absence of evidence to support this practice. The goal of the current study was to ascertain the effect of olive oil and sunflower seed oil on the biophysical properties of the skin. Nineteen adult volunteers with and without a history of atopic dermatitis were recruited into two randomized forearm-controlled mechanistic studies. The first cohort applied six drops of olive oil to one forearm twice daily for 5 weeks. The second cohort applied six drops of olive oil to one forearm and six drops of sunflower seed oil to the other twice daily for 4 weeks. The effect of the treatments was evaluated by determining stratum corneum integrity and cohesion, intercorneocyte cohesion, moisturization, skin-surface pH, and erythema. Topical application of olive oil for 4 weeks caused a significant reduction in stratum corneum integrity and induced mild erythema in volunteers with and without a history of atopic dermatitis. Sunflower seed oil preserved stratum corneum integrity, did not cause erythema, and improved hydration in the same volunteers. In contrast to sunflower seed oil, topical treatment with olive oil significantly damages the skin barrier, and therefore has the potential to promote the development of, and exacerbate existing, atopic dermatitis. The use of olive oil for the treatment of dry skin and infant massage should therefore be discouraged. These findings challenge the unfounded belief that all natural oils are beneficial for the skin and highlight the need for further research.

An Investigation of the Skin Barrier Restoring Effects of a Cream and Lotion Containing Ceramides in a Multi-vesicular Emulsion in People with Dry, Eczema-Prone, Skin: The RESTORE Study Phase 1.

INTRODUCTION: The replenishment of skin lipids depleted in the dry skin state is a desirable therapeutic target to restore skin moisturization; however, there is limited evidence demonstrating the success of this approach through the use of topical emollients. The purpose of this study was to provide evidence of the benefits of a cream and equivalent lotion containing skin lipids in a multi-vesicular emulsion for the management of dry skin. The hypothesis was that the test cream and test lotion could sustain skin moisturization for longer than traditional emollients by sustainably delivering skin lipids. METHODS: A double-blind intra-subject vehicle-controlled single open-application test on the lower legs in people with dry, atopic dermatitis (atopic eczema)-prone, skin was conducted. There were six treatment sites, three per lower leg in each participant, which were treated with the test cream, the test lotion, three reference creams commonly prescribed in the UK and no treatment as a control. After baseline measurements of skin hydration, 100 µl of the test/reference creams was applied to each of the relevant treatment sites (random site allocation). Following treatment, measurements of skin hydration and scoring of visual dryness was conducted at timed intervals (3, 6, 12 and 24 h post-product application). RESULTS: The test cream and lotion both significantly increased skin hydration and reduced skin dryness for at least 24 h following a single application compared to a no treatment control site. Compared to three reference emollient creams the test cream and test lotion were the only products capable of sustaining clinically meaningful improvements in skin moisturization for 24 h. CONCLUSION: The sustained moisturization imparted by the test products reduces the need for frequent emollient application, often requiring 3-4 applications per day for traditional emollients, and should reduce the high burden of managing dry skin conditions like atopic dermatitis.

Pedigree-free animal models: the relatedness matrix reloaded.

Animal models typically require a known genetic pedigree to estimate quantitative genetic parameters. Here we test whether animal models can alternatively be based on estimates of relatedness derived entirely from molecular marker data. Our case study is the morphology of a wild bird population, for which we report estimates of the genetic variance-covariance matrices (G) of six morphological traits using three methods: the traditional animal model; a molecular marker-based approach to estimate heritability based on Ritland's pairwise regression method; and a new approach using a molecular genealogy arranged in a relatedness matrix (R) to replace the pedigree in an animal model. Using the traditional animal model, we found significant genetic variance for all six traits and positive genetic covariance among traits. The pairwise regression method did not return reliable estimates of quantitative genetic parameters in this population, with estimates of genetic variance and covariance typically being very small or negative. In contrast, we found mixed evidence for the use of the pedigree-free animal model. Similar to the pairwise regression method, the pedigree-free approach performed poorly when the full-rank R matrix based on the molecular genealogy was employed. However, performance improved substantially when we reduced the dimensionality of the R matrix in order to maximize the signal to noise ratio. Using reduced-rank R matrices generated estimates of genetic variance that were much closer to those from the traditional model. Nevertheless, this method was less reliable at estimating covariances, which were often estimated to be negative. Taken together, these results suggest that pedigree-free animal models can recover quantitative genetic information, although the signal remains relatively weak. It remains to be determined whether this problem can be overcome by the use of a more powerful battery of molecular markers and improved methods for reconstructing genealogies.

The Effect of Water Hardness on Surfactant Deposition after Washing and Subsequent Skin Irritation in Atopic Dermatitis Patients and Healthy Control Subjects.

Living in a hard water area is associated with an increased risk of atopic dermatitis (AD). Greater skin barrier impairment after exposure to surfactants in wash products, combined with the high calcium levels of hard water and/or high chlorine levels, is a compelling mechanism for this increase. The purpose of this study was to investigate this mechanism in individuals with and without a predisposition to skin barrier impairment. We recruited 80 participants: healthy control subjects and AD patients with and without FLG mutations. The skin of each participant was washed with sodium lauryl sulfate in water of varying hardness levels and chlorine concentrations, rinsed, and covered with chambers to determine the effects of surfactant residues. Sites washed with hard water had significantly increased sodium lauryl sulfate deposits. These deposits increased transepidermal water loss and caused irritation, particularly in AD patients carrying FLG mutations. A clear effect of chlorine was not observed. Water softening by ion-exchange mitigated the negative effects of hard water. Barrier impairment resulting from the interaction between hard water and surfactants is a contributory factor to the development of AD. Installation of a water softener in early life may be able to prevent AD development. An intervention study is required to test this hypothesis.