A functional mechanistic study of the effect of emollients on the structure and function of the skin barrier

A Programmable Handheld Extrusion-Based Bioprinting Platform for In Situ Skin Wounds Dressing: Balance Mobility and Customizability

Bioprinting technology plays a crucial role for constructing tissue substitutes. However, the mismatched scaffold shapes and the poor treatment timeliness limit its clinical translational application. In situ printing technology that prints bioregenerants directly inside patient's body can meet the needs of specific tissue repair. This study develops a smartphone controlled handheld bioprinter for in situ skin wounds dressing. The mini bioprinter can be handheld and placed on any printing surface to create strips, complex patterns, and 3D structures, and can be equipped with microchannel needles to expand functionality. The size of the strips as well as the printing path can be programmed and controlled by the smartphone to ensure the precision of the printed product quality. Furthermore, the device not only allows for smooth switching between different bioinks for printing heterogeneous structure, but also allows for fast and uniform coverage of large wound surfaces. When dealing with complex wounds in vitro & vivo, the printer can effectively fill and precisely close wounds, promoting wound healing. The programmable handheld bioprinter can balance mobility and customizability in the management of skin wounds and is expected to realize its potential for emergency medical treatment in condition-constrained scenarios, such as battlefields or disaster areas.

Emollient application from birth to prevent eczema in high-risk children: the BEEP RCT

Background

Atopic eczema is a common childhood skin problem linked with asthma, food allergy and allergic rhinitis that impairs quality of life.

Objectives

To determine whether advising parents to apply daily emollients in the first year can prevent eczema and/or other atopic diseases in high-risk children.

Design

A United Kingdom, multicentre, pragmatic, two-arm, parallel-group randomised controlled prevention trial with follow-up to 5 years.

Setting

Twelve secondary and four primary care centres.

Participants

Healthy infants (at least 37 weeks' gestation) at high risk of developing eczema, screened and consented during the third trimester or post delivery.

Interventions

Infants were randomised (1 : 1) within 21 days of birth to apply emollient (Doublebase Gel®; Dermal Laboratories Ltd, Hitchin, UK or Diprobase Cream®) daily to the whole body (excluding scalp) for the first year, plus standard skin-care advice (emollient group) or standard skin-care advice only (control group). Families were not blinded to allocation.

Main outcome measures

Primary outcome was eczema diagnosis in the last year at age 2 years, as defined by the UK Working Party refinement of the Hanifin and Rajka diagnostic criteria, assessed by research nurses blinded to allocation. Secondary outcomes up to age 2 years included other eczema definitions, time to onset and severity of eczema, allergic rhinitis, wheezing, allergic sensitisation, food allergy, safety (skin infections and slippages) and cost-effectiveness.

Results

One thousand three hundred and ninety-four newborns were randomised between November 2014 and November 2016; 693 emollient and 701 control. Adherence in the emollient group was 88% (466/532), 82% (427/519) and 74% (375/506) at 3, 6 and 12 months. At 2 years, eczema was present in 139/598 (23%) in the emollient group and 150/612 (25%) in controls (adjusted relative risk 0.95, 95% confidence interval 0.78 to 1.16; p = 0.61 and adjusted risk difference -1.2%, 95% confidence interval -5.9% to 3.6%). Other eczema definitions supported the primary analysis. Food allergy (milk, egg, peanut) was present in 41/547 (7.5%) in the emollient group versus 29/568 (5.1%) in controls (adjusted relative risk 1.47, 95% confidence interval 0.93 to 2.33). Mean number of skin infections per child in the first year was 0.23 (standard deviation 0.68) in the emollient group versus 0.15 (standard deviation 0.46) in controls; adjusted incidence rate ratio 1.55, 95% confidence interval 1.15 to 2.09. The adjusted incremental cost per percentage decrease in risk of eczema at 2 years was £5337 (£7281 unadjusted). No difference between the groups in eczema or other atopic diseases was observed during follow-up to age 5 years via parental questionnaires.

Limitations

Two emollient types were used which could have had different effects. The median time for starting emollients was 11 days after birth. Some contamination occurred in the control group (< 20%). Participating families were unblinded and reported on some outcomes.

Conclusions

We found no evidence that daily emollient during the first year of life prevents eczema in high-risk children. Emollient use was associated with a higher risk of skin infections and a possible increase in food allergy. Emollient use is unlikely to be considered cost-effective in this context.

Future research

To pool similar studies in an individual patient data meta-analysis.

Trial registration

This trial is registered as ISRCTN21528841.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 12/67/12) and is published in full in Health Technology Assessment; Vol. 28, No. 29. See the NIHR Funding and Awards website for further award information.

Skin-centered strategies in food allergy prevention

While the early introduction of food allergens in the infant diet has been shown to be effective at preventing the development of food allergy (FA), its implementation in real life has been associated with various challenges. Interventions aimed at correcting skin barrier dysfunction have been explored in recent decades as a distinct or complementary mean to prevent allergic sensitization through the skin and subsequent development of FA. Studies assessing the application of emollient from birth have yielded conflicting results, and meta-analyses have demonstrated either no effect or only a slight positive effect on FA prevention. However, a careful review of the clinical trials reveals that different emollients were used, which may have explained some of the discrepancies between study results. Emollient application protocols also varied widely between studies. While firm conclusions cannot be drawn with regard to their overall efficacy at preventing FA, the available data provide valuable insight into the characteristics that could be associated with a more effective intervention. Namely, successful trials tended to use emollients with an acidic pH of 5.5, applied over the entire body, and combined with topical corticosteroids in affected areas. Consensus on the optimal strategy to restore skin barrier function could help improve the homogeneity and clinical relevance of future trials on this topic. In the meantime, clinicians should avoid products associated with worse outcomes.

Revitalizing the skin: Exploring the role of barrier repair moisturizers

BACKGROUND

Moisturizers are designed to maintain skin health and treat dermatological conditions associated with impaired skin barrier function. However, differences in their composition account for the differences in their effect.

AIMS

This narrative review aims to discuss the role of barrier repair moisturizers, highlight the role of different components in a moisturizer and their role in impaired skin conditions (e.g., dry, itchy, inflamed, sensitive skin, atopic eczema), and thereby empower dermatologists and pediatricians in selecting the right moisturizer.

METHODS

PubMed, Embase, and Scopus electronic databases were searched from January 2000 to June 2023 for publications on skin barrier repair and use of barrier repair moisturizers for the treatment of dry, itchy, inflamed, sensitive skin, or atopic eczema. Studies conducted in humans, published in English for which full texts were freely available were included.

RESULTS

The structure and composition of lipid lamellae within the stratum corneum play an important role in maintaining an effective skin barrier and protecting the body from various external assaults. Endocannabinoid mediators play an active role in maintaining skin barrier function. Moisturizers containing physiological lipids and functional ingredients (e.g., endocannabinoids such as palmitoylethanolamide [PEA]) and based on the principles of biomimic technology are demonstrated to be beneficial for the management of conditions associated with a disrupted skin barrier.

CONCLUSIONS

Moisturizer based on the innovative biomimic formulation has good cosmetic efficacy and is generally well tolerated, and the addition of PEA might represent a new generation of compounds that may be beneficial for long-term management of impaired skin conditions.

Skin Barrier in Atopic Dermatitis

A compromised permeability barrier is a hallmark of atopic dermatitis (AD). Localized to the outermost skin layer, the stratum corneum (SC) is critically dependent on terminal differentiation of epidermal keratinocytes, which transform into protein-rich corneocytes surrounded by extracellular lamellae of unique epidermal lipids, conferring permeability barrier function. These structures are disrupted in AD. A leaky barrier is prone to environmental insult, which in AD elicits type 2-dominant inflammation, in turn resulting in a vicious cycle further impairing the SC structure. Therapies directed at enforcing SC structure and anti-inflammatory strategies administered by topical and systemic route as well as UV therapy have differential effects on the permeability barrier. The expanding armamentarium of therapeutic modalities for AD treatment warrants optimization of their effects on permeability barrier function.

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.

Evaluation of Scalp Hydration and pH Values in Hijab-Wearing and Non-Hijab-Wearing Women

Introduction

Indonesia is the most populous Muslim-majority country, where some women wear hijab covering their scalp and neck. Some hijab-wearing women complain of scalp problems eg, itch, dandruff, and hair loss, which might be related to severe and chronic skin barrier impairment due to occlusion. Excessive water accumulation in the occluded stratum corneum might result in increased permeability, followed by increased skin pH values. This study aimed to evaluate scalp hydration and pH values in hijab-wearing and non-hijab-wearing women.

Material and Methods

This was a cross-sectional comparative analytical study using stratified random sampling methods conducted on 63 subjects, who were divided into two groups, consisting of 33 hijab-wearing and 30 non-hijab-wearing women. Both groups underwent physical examination and their medical history recorded. Scalp hydration was measured using a Corneometer (Courage + Khazaka, Koln, Germany), and scalp pH value was measured using a Skin & Scalp pH Tester (Hanna Instruments® HI981037, Rumania). This study was conducted at the Dermatology and Venereology Clinic of Hasan Sadikin General Hospital Bandung.

Results

The mean scalp hydration and pH values were 18.34 ± 2.91 AU and 4.93 ± 0.17, respectively, in hijab-wearing women. Meanwhile, the mean scalp hydration and pH values were 17.71 ± 3.35 AU and 4.91 ± 0.16, respectively, in non-hijab-wearing women. The difference of scalp hydration and pH values between the groups was not statistically significant based on the independent t-test, with p-values of 0.430 and 0.597, respectively.

Conclusion

Scalp hydration and pH values in hijab-wearing and non-hijab-wearing women did not differ significantly. Hijab-wearing women should not worry about scalp barrier impairment as long as they do not have any history of underlying scalp and skin disorders, and do not wear hijab in wet condition.

Targeting Skin Barrier Function in Atopic Dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in the general population. Skin barrier dysfunction is the central abnormality leading to AD. The cause of skin barrier dysfunction is complex and rooted in genetic mutations, interactions between the immune pathway activation and epithelial cells, altered host defense mechanisms, as well as environmental influences that cause epithelial cell activation and release of alarmins (such as thymic stromal lymphopoietin) that can activate the type 2 immune pathway, including generation of interleukins 4 and 13, which induces defects in the skin barrier and increased allergic inflammation. These inflammatory pathways are further influenced by environmental factors including the microbiome (especially Staphylococcus aureus), air pollution, stress, and other factors. As such, AD is a syndrome involving multiple phenotypes, all of which have in common skin barrier dysfunction as a key contributing factor. Understanding mechanisms leading to skin barrier dysfunction in AD is pointing to the development of new topical and systemic treatments in AD that helps keep skin borders secure and effectively treat the disease.

Epicutaneous Sensitization and Food Allergy: Preventive Strategies Targeting Skin Barrier Repair-Facts and Challenges

Food allergy represents a growing public health and socio-economic problem with an increasing prevalence over the last two decades. Despite its substantial impact on the quality of life, current treatment options for food allergy are limited to strict allergen avoidance and emergency management, creating an urgent need for effective preventive strategies. Advances in the understanding of the food allergy pathogenesis allow to develop more precise approaches targeting specific pathophysiological pathways. Recently, the skin has become an important target for food allergy prevention strategies, as it has been hypothesized that allergen exposure through the impaired skin barrier might induce an immune response resulting in subsequent development of food allergy. This review aims to discuss current evidence supporting this complex interplay between the skin barrier dysfunction and food allergy by highlighting the crucial role of epicutaneous sensitization in the causality pathway leading to food allergen sensitization and progression to clinical food allergy. We also summarize recently studied prophylactic and therapeutic interventions targeting the skin barrier repair as an emerging food allergy prevention strategy and discuss current evidence controversies and future challenges. Further studies are needed before these promising strategies can be routinely implemented as prevention advice for the general population.

Moisturizer therapy in prevention of atopic dermatitis and food allergy: To use or disuse?

OBJECTIVE

To critically appraise the evidence for the role of regular moisturizer application in early life to prevent atopic dermatitis (AD) and food allergy (FA).

DATA SOURCES

Primary peer-reviewed literature.

STUDY SELECTIONS

Original research articles based on systematic reviews, interventional studies, retrospective studies, case-control studies, and cohort studies related to the subject matter.

RESULTS

There is good evidence to show that epicutaneous sensitization through a defective skin barrier is important in the development of AD and FA. This supports moisturizer use in prevention because some of them have been proven to restore skin barrier with clear benefits in AD, whereas there is some limited evidence that these products may reduce allergic sensitization. However, moisturizers have varied effects depending on ingredients and formulation, some of which are paradoxical, such as increasing transepidermal water loss and enhancing penetration of substances in the skin. These effects may be responsible for some of the conflicting outcomes of prevention studies, some of which suggest that moisturizers are not useful in prevention of AD and FA, whereas others show a positive trend. Interestingly, there is some suggestion that moisturizers may increase the risk for allergy development perhaps through these paradoxical effects.

CONCLUSION

Although moisturizer use is beneficial in the management of AD, current evidence suggests that it may be ineffective in prevention of AD and FA. Further studies are needed to determine the effects of moisturization on allergic sensitization and inflammation and to investigate whether moisturizer type, frequency, duration, and age of application substantially affect the prevention and development of these allergies.

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.

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 atopic dermatitis (AD) patients is characterised by abnormal stratum corneum (SC) lipid levels. Consequently, the lamellar matrices are disrupted and skin barrier function is diminished, increasing skin sensitivity to irritants and allergens.

OBJECTIVE

To determine whether a cream containing ceramides, triglycerides and cholesterol in a multi-vesicular emulsion can reinforce the skin barrier, and protect against skin irritation.

METHODS

A randomized observer-blind intrasubject-controlled study in 34 adults with dry, eczema-prone, skin was conducted. Each participant underwent 4 weeks 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 FTIR spectroscopy using a novel interface.

RESULTS

Skin barrier integrity was greater at sites treated with the Test cream (effect size -161.9 area-under-the-TEWL-curve, 95% CI -205.5, -118.3), and skin sensitivity to sodium lauryl sulfate reduced (-0.5 points [97.57% CI -1.00, -0.25] visual redness and -15.34 g/m² /h [95% CI -20.28, -10.40] TEWL) compared to the reference. Sites treated with the test cream displayed enhanced lipid chain ordering, which was significantly associated with skin barrier integrity (r0.606). Compared to the reference, treatment with the Test cream increased hydration (8.61 capacitance units, 95% CI 6.61 to 10.60) and decreased signs of dryness.

CONCLUSION

The Test cream facilitates skin barrier restoration and protects the skin from dryness and irritation. Compared to a commonly prescribed emollient in the UK, the Test cream is highly suited to the management of dry, sensitive, skin.

Validation of a novel patient-operated device for measuring skin barrier function in atopic dermatitis

BACKGROUND

Transepidermal water loss (TEWL) and capacitance are used in atopic dermatitis (AD) trials to provide objective data on clinical change and response to therapy. Many barrier devices are costly, limiting their utility. GPSkin is a novel low-cost, patient-operable device that measures both TEWL and capacitance via smartphone application.

OBJECTIVE

This validation study investigated the correlation of GPSkin with the AquaFlux and Corneometer, and the reliability of these devices, in patients with AD.

METHODS

Fifty AD patients with varying disease severity performed self-measurements with GPSkin, while investigators collected data with all 3 devices, on both nonlesional and lesional skin.

CONCLUSION

GPSkin and AquaFlux demonstrated strong correlation for TEWL on nonlesional and lesional skin by Spearman's correlation (r_s ), independent of device user. For capacitance, GPSkin and the Corneometer showed moderate correlation when obtained by patients, yet a strong correlation when obtained by a clinician. Despite good correlation, GPSkin showed poor agreement with both the AquaFlux and Corneometer in Bland-Altman plots. GPSkin underestimated both TEWL and capacitance. Overall, the devices had good test-retest reliability. None of the devices could discriminate between AD severity states. While GPSkin marks an exciting advancement in barrier technology, further study is needed for validation on AD skin.

Effects of skin moisturizer on the skin barrier dysfunction model: An evaluation of the heel via tape-stripping in healthy, young adults

BACKGROUND

This study seeks to establish the skin barrier dysfunction model at the heel via tape-stripping (TS) by evaluating the skin moisturizing effects.

MATERIALS AND METHODS

Nineteen young, female participated in the study. A sequence of TS was performed at the heel and trans-epidermal water loss (TEWL), stratum corneum (SC) hydration, and surface pH were measured. Following TS, the subjects were divided into three groups: moisturizer, emollient, and overcoat. These agents were applied daily at night, and the skin parameters were measured the next morning for a week.

RESULTS

The TEWL value of TS immediately and 5 min after TS were significantly higher than what was obtained before TS, while the SC hydration after TS was significantly lower than what was obtained before TS. However, there were no significant differences in the skin parameters among the three agents on day 7 after application, with the two-way ANOVA showing no interaction among the agents and number of days.

CONCLUSION

The skin barrier dysfunction model at the heel was established by TS in healthy, young adults. However, the physiological function of the skin at the heel did not change drastically and showed no differences even after continuous application for 7 days.

Topical corticosteroid vehicle composition and implications for clinical practice

This narrative review highlights the therapeutic significance of topical corticosteroid (TCS) vehicles and provides subsequent guidance to improve clinical and research outcomes. A greater understanding of the relationship between the topical vehicle, corticosteroid and skin is needed to ensure safer, more effective treatment for patients. Topical vehicles are not inert and can affect TCS bioavailability, due to the ability of their composition to positively or negatively influence skin status and change the physiochemical characteristics of an inherent corticosteroid. However, this principle is not commonly understood, and has contributed to inconsistencies in potency classification systems. This review provides an insight into the research methods and standardization needed to determine TCS product bioavailability. It identifies formulation components responsible for vehicle composition that underpin the quality, stability, compounding and functionalities of vehicle ingredients. This helps to contextualize how topical vehicles can be responsible for clinically significant effects, and how their composition gives products unique properties. In turn, this facilitates a more in-depth understanding of which resources offer information to inform the best selection of TCS products and why products should be prescribed by brand or manufacturer. This review will better equip clinicians and formulary teams to appraise products. It will also inform prescribing of Specials and why products should not be manipulated. The recommendations, accompanied by patient perspectives on using TCS products, assist clinical decision-making. They also identify the need for research into concomitant application of TCS products with other topical therapies.

Evidence of Skin Barrier Damage by Cyclic Siloxanes (Silicones)-Using Digital Holographic Microscopy

Cyclic siloxanes (D4, D5, D6) are widely used in skin products. They improve skin sensory properties and alleviate dry skin, but there is still one report (published 2019), which regards their effects on the destruction of the skin barrier, by using fluorescence microscopy and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). A new skin-imaging technique, digital holographic microscopy (DHM), was used for the first time to investigate the impact of D4, D5, and D6 on the skin barrier. We observed irreversible damage of the stratum corneum due to the interaction with cyclic siloxanes. These substances changed: (a) the first level of the skin barrier through destabilization of the intercellular lipid lamellae and destruction of the corneocyte structure (measured with axial nanometer resolution), (b) the second level by collapse of not only corneocytes but also of a significant part of the clusters, leading to the loss of the stratum corneum integrity and formation of the lacunae, (c) the third level as an effect of the change in the surface geometrical topography of the stratum corneum and disruption of the integrity of this skin layer, measured with lateral micrometer resolution. DHM allowed also to identify an important pathway for substances to penetrate into the skin through canyons surrounding the clusters. Our investigations provide advanced information for understanding the mechanisms by which various substances pass the skin barrier, including uncontrolled diffusion into the skin.

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.

A randomized half-body, double blind, controlled trial on the effects of a pH-modified moisturizer vs. standard moisturizer in mild to moderate atopic dermatitis

Background

Higher skin pH in atopic dermatitis contributes to impaired epidermal barrier. A moisturizer compatible with physiological pH could improve atopic dermatitis.

Objective

To determine the effect of a physiologically compatible pH moisturizer in atopic dermatitis.

Methods

A randomized half body, double blind, controlled trial involving patients with stable atopic dermatitis was performed. pH-modified moisturizer and standard moisturizer were applied to half body for 6 weeks.

Results

A total of 6 (16.7%) males and 30 (83.3%) females participated. Skin pH reductions from week 0, week 2 and 6 were significant at the forearms (5.315 [0.98] to 4.85 [0.54] to 5.04 [0.78], p = 0.02) and abdomen (5.25 [1.01], 4.82 [0.64], 5.01 [0.59], p = 0.00) but not at the shins (5.01 [0.80], 4.76 [0.49], 4.85 [0.79], p = 0.09) with pH-modified moisturizer. Transepidermal water loss (TEWL) at the forearms decreased (4.60 [2.55] to 3.70 [3.10] to 3.00 [3.55], p = 0.00), abdomen (3.90 [2.90] to 2.40 [3.45] to 2.70 [2.25], p = 0.046). SCORAD improved from 14.1 ± 12.75 to 10.5 ± 13.25 to 7 ± 12.25, p = 0.00. In standard moisturizer group, pH reductions were significant at the forearms (5.29 [0.94] to 4.84 [0.55] to 5.02 [0.70], p = 0.00) and abdomen (5.25 [1.09], 4.91 [0.63], 5.12 [0.66], p = 0.00). TEWL at the forearm were (4.80 [2.95], 4.10 [2.15], 4.60 [3.40], p = 0.67), shins (3.80 [1.40], 3.50 [2.35], 4.00 [2.50], p = 0.91) and abdomen (3.70 [2.45], 4.10 [3.60], 3.40 [2.95], p = 0.80). SCORAD improved from 14.2 ± 9.1 to 10.9 ± 10.65 to 10.5 ± 11, p = 0.00. Reduction in pH was observed with both moisturizers while TEWL significantly improved with pH-modified moisturizer. pH-modified moisturizer resulted in greater pH, TEWL and SCORAD improvements however the differences were not significant from standard moisturizer.

Study limitation

Skin hydration was not evaluated.

Conclusion

Moisturization is beneficial for atopic dermatitis; use of physiologically compatible pH moisturizer is promising.

Daily emollient during infancy for prevention of eczema: the BEEP randomised controlled trial

BACKGROUND

Skin barrier dysfunction precedes eczema development. We tested whether daily use of emollient in the first year could prevent eczema in high-risk children.

METHODS

We did a multicentre, pragmatic, parallel-group, randomised controlled trial in 12 hospitals and four primary care sites across the UK. Families were approached via antenatal or postnatal services for recruitment of term infants (at least 37 weeks' gestation) at high risk of developing eczema (ie, at least one first-degree relative with parent-reported eczema, allergic rhinitis, or asthma, diagnosed by a doctor). Term newborns with a family history of atopic disease were randomly assigned (1:1) to application of emollient daily (either Diprobase cream or DoubleBase gel) for the first year plus standard skin-care advice (emollient group) or standard skin-care advice only (control group). The randomisation schedule was created using computer-generated code (stratified by recruiting centre and number of first-degree relatives with atopic disease) and participants were assigned to groups using an internet-based randomisation system. The primary outcome was eczema at age 2 years (defined by UK working party criteria) with analysis as randomised regardless of adherence to allocation for participants with outcome data collected, and adjusting for stratification variables. This trial is registered with ISRCTN, ISRCTN21528841. Data collection for long-term follow-up is ongoing, but the trial is closed to recruitment.

FINDINGS

1394 newborns were randomly assigned to study groups between Nov 19, 2014, and Nov 18, 2016; 693 were assigned to the emollient group and 701 to the control group. Adherence in the emollient group was 88% (466 of 532) at 3 months, 82% (427 of 519) at 6 months, and 74% (375 of 506) at 12 months in those with complete questionnaire data. At age 2 years, eczema was present in 139 (23%) of 598 infants with outcome data collected in the emollient group and 150 (25%) of 612 infants in the control group (adjusted relative risk 0·95 [95% CI 0·78 to 1·16], p=0·61; adjusted risk difference -1·2% [-5·9 to 3·6]). Other eczema definitions supported the results of the primary analysis. Mean number of skin infections per child in year 1 was 0·23 (SD 0·68) in the emollient group versus 0·15 (0·46) in the control group; adjusted incidence rate ratio 1·55 (95% CI 1·15 to 2·09).

INTERPRETATION

We found no evidence that daily emollient during the first year of life prevents eczema in high-risk children and some evidence to suggest an increased risk of skin infections. Our study shows that families with eczema, asthma, or allergic rhinitis should not use daily emollients to try and prevent eczema in their newborn.

FUNDING

National Institute for Health Research Health Technology Assessment.

Research Techniques Made Simple: Transepidermal Water Loss Measurement as a Research Tool

Transepidermal water loss (TEWL) is the most widely used objective measurement for assessing the barrier function of skin in healthy individuals but also patients with skin diseases that are associated with skin barrier dysfunction, such as atopic dermatitis. TEWL is the quantity of condensed water that diffuses across a fixed area of stratum corneum to the skin surface per unit time. The water evaporating from the skin is measured using a probe that is placed in contact with the skin surface and contains sensors that detect changes in water vapor density. TEWL can be measured using an open-chamber, unventilated-chamber, or condenser-chamber device. It is a sensitive measure that is affected by properties of the surrounding microclimate such as environmental humidity, temperature, and airflow and should be measured under controlled conditions. TEWL varies significantly across different anatomical sites and also depends on sweat gland activity, skin temperature, and corneocyte properties. Here we describe how to optimally use TEWL measurements as a skin research tool in vivo and in vitro.

Novel confocal Raman microscopy method to investigate hydration mechanisms in human skin

BACKGROUND

Skin hydration is essential for maintaining stratum corneum (SC) flexibility and facilitating maturation events. Moisturizers contain multiple ingredients to maintain and improve skin hydration although a complete understanding of hydration mechanisms is lacking. The ability to differentiate the source of the hydration (water from the environment or deeper skin regions) upon application of product will aid in designing more efficacious formulations.

MATERIALS AND METHODS

Novel confocal Raman microscopy (CRM) experiments allow us to investigate mechanisms and levels of hydration in the SC. Using deuterium oxide (D₂ O) as a probe permits the differentiation of endogenous water (H₂ O) from exogenous D₂ O. Following topical application of D₂ O, we first compare in vivo skin depth profiles with those obtained using ex vivo skin. Additional ex vivo experiments are conducted to quantify the kinetics of D₂ O diffusion in the epidermis by introducing D₂ O under the dermis.

RESULTS

Relative D₂ O depth profiles from in vivo and ex vivo measurements compare well considering procedural and instrumental differences. Additional in vivo experiments where D₂ O was applied following topical glycerin application increased the longevity of D₂ O in the SC. Reproducible rates of D₂ O diffusion as a function of depth have been established for experiments where D₂ O is introduced under ex vivo skin.

CONCLUSION

Unique information regarding hydration mechanisms are obtained from CRM experiments using D₂ O as a probe. The source and relative rates of hydration can be delineated using ex vivo skin with D₂ O underneath. One can envision comparing these depth-dependent rates in the presence and absence of topically applied hydrating agents to obtain mechanistic information.

Comprehensive mapping of human body skin hydration: A pilot study

BACKGROUND

Previous studies analyzed a series of representative anatomical regions in the human body; however, there is a wide structural and cellular variability in the constitution of the skin. Our objective was to perform a comprehensive assessment of human skin hydration throughout the largest possible area.

MATERIALS AND METHODS

Hydration was registered by Corneometer^® CM825 probe in 23 anatomical regions of five healthy men. Each zone was analyzed by 2-cm segments in the supine, prone, and lateral positions. A total of 7863 measurements were registered.

RESULTS

Differences in the degree of hydration among the prone, supine, and lateral regions were observed. The chest and back showed a pattern of increased hydration toward the neck area. Higher levels of hydration were evidenced in the proximal areas and in the regions near the elbow and knee. The regions of greater mechanical wear and with greater exposure to the sun exhibited a lower degree of hydration.

CONCLUSION

The human skin exhibited hydration patterns influenced by anatomical function and the degree of sun exposure. Detailed information of the hydration patterns could serve as reference for the design of topical products, as an indicator of their effectiveness, and for the monitoring of skin pathologies.

Systemic Pharmacokinetics, Safety, and Preliminary Efficacy of Topical AhR Agonist Tapinarof: Results of a Phase 1 Study

Tapinarof cream is a novel topical nonsteroidal agent that represents a unique class of anti-inflammatory molecules targeting the aryl hydrocarbon receptor. Study 201851 was an open-label, 2-cohort sequential study that assessed the systemic pharmacokinetics, safety, and efficacy of tapinarof in adults with moderate to severe atopic dermatitis. A total of 11 participants were enrolled: 5 received 2% cream, and 6 received 1% cream. Tapinarof was systemically absorbed, and measurable amounts were detected in both cohorts. Generally, plasma exposure was greater with the 2% cream and decreased from day 1 to day 21. Median T_max ranged from 1 to 4 hours. Preliminary efficacy results were similar between the 1% and 2% concentrations, with the 1% cream showing better tolerability based on 3 subjects in the 2% cohort who discontinued treatment because of systemic AEs. The efficacy and safety of 1% tapinarof support results of previous positive studies that used a different formulation. However, conclusions in the present study are limited because of the open-label design and small number of participants. The 1% cream was selected as the concentration for use in future studies because of its lower AE incidence and efficacy comparable to the 2% cream.

Emollients and moisturizers for eczema: abridged Cochrane systematic review including GRADE assessments

Eczema is a chronic inflammatory skin disorder with considerable impact on quality of life. Emollients or moisturizers are widely recommended, but are these effective and safe? We searched for randomized controlled trials (RCTs) in the Cochrane Skin Group Specialised Skin Register, CENTRAL in The Cochrane Library, MEDLINE, Embase, LILACS, the GREAT database and five trial registers to December 2015. We included 77 RCTs with 6603 participants. Seven studies (9%) were at low risk of bias, 34 (44%) had unclear risk and 36 (47%) were at high risk. The quality of the evidence was mainly low or moderate for the prespecified outcomes. The most important comparison, 'moisturizer vs. no moisturizer', showed improved Scoring Atopic Dermatitis values in the moisturizer group compared with no moisturizer [mean difference -2·42, 95% confidence interval (CI) -4·55 to -0·28], but did not meet the minimal important difference of 8·7. Fewer flares were seen (risk ratio 0·40, 95% CI 0·23-0·70) and the rate of flares was reduced (hazard ratio 3·74, 95% CI 1·86-7·50). The groups applying moisturizer used less topical corticosteroids over 6-8 weeks (mean difference -9·30 g, 95% CI 15·3 to -3·27). Glycyrrhetinic acid-, urea- and glycerol-containing creams worked better than their controls (vehicle, placebo or no moisturizer) according to both participants and physicians. More flares were reported with moisturizer alone than when combined with twice-weekly fluticasone propionate (risk ratio 2·17, 95% CI 1·55-3·11). Adding moisturizers to topical anti-inflammatory treatment was more effective than anti-inflammatory treatment alone and resulted in fewer flares.

Effectiveness and cost-effectiveness of daily all-over-body application of emollient during the first year of life for preventing atopic eczema in high-risk children (The BEEP trial): protocol for a randomised controlled trial

BACKGROUND

Atopic eczema (AE) is a common skin problem that impairs quality of life and is associated with the development of other atopic diseases including asthma, food allergy and allergic rhinitis. AE treatment is a significant cost burden for health care providers. The purpose of the trial is to investigate whether daily application of emollients for the first year of life can prevent AE developing in high-risk infants (first-degree relative with asthma, AE or allergic rhinitis).

METHODS

This is a protocol for a pragmatic, two-arm, randomised controlled, multicentre trial. Up to 1400 term infants at high risk of developing AE will be recruited through the community, primary and secondary care in England. Participating families will be randomised in a 1:1 ratio to receive general infant skin-care advice, or general skin-care advice plus emollients with advice to apply daily to the infant for the first year of life. Families will not be blinded to treatment allocation. The primary outcome will be a blinded assessment of AE at 24 months of age using the UK Working Party Diagnostic Criteria for Atopic Eczema. Secondary outcomes are other definitions of AE, time to AE onset, severity of AE (EASI and POEM), presence of other allergic diseases including food allergy, asthma and hay fever, allergic sensitisation, quality of life, cost-effectiveness and safety of the emollients. Subgroup analyses are planned for the primary outcome according to filaggrin genotype and the number of first-degree relatives with AE and other atopic diseases. Families will be followed up by online and postal questionnaire at 3, 6, 12 and 18 months with a face-to-face visit at 24 months. Long-term follow-up until 60 months will be via annual questionnaires.

DISCUSSION

This trial will demonstrate whether skin-barrier enhancement through daily emollient for the first year of life can prevent AE from developing in high-risk infants. If effective, this simple and cheap intervention has the potential to result in significant cost savings for health care providers throughout the world by preventing AE and possibly other associated allergic diseases.

TRIAL REGISTRATION

ISRCTN registry; ID: ISRCTN21528841 . Registered on 25 July 2014.

Emollients and moisturisers for eczema

BACKGROUND

Eczema is a chronic skin disease characterised by dry skin, intense itching, inflammatory skin lesions, and a considerable impact on quality of life. Moisturisation is an integral part of treatment, but it is unclear if moisturisers are effective.

OBJECTIVES

To assess the effects of moisturisers for eczema.

SEARCH METHODS

We searched the following databases to December 2015: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, the GREAT database. We searched five trials registers and checked references of included and excluded studies for further relevant trials.

SELECTION CRITERIA

Randomised controlled trials in people with eczema.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 77 studies (6603 participants, mean age: 18.6 years, mean duration: 6.7 weeks). We assessed 36 studies as at a high risk of bias, 34 at unclear risk, and seven at low risk. Twenty-four studies assessed our primary outcome 'participant-assessed disease severity', 13 assessed 'satisfaction', and 41 assessed 'adverse events'. Secondary outcomes included investigator-assessed disease severity (addressed in 65 studies), skin barrier function (29), flare prevention (16), quality of life (10), and corticosteroid use (eight). Adverse events reporting was limited (smarting, stinging, pruritus, erythema, folliculitis).Six studies evaluated moisturiser versus no moisturiser. 'Participant-assessed disease severity' and 'satisfaction' were not assessed. Moisturiser use yielded lower SCORAD than no moisturiser (three studies, 276 participants, mean difference (MD) -2.42, 95% confidence interval (CI) -4.55 to -0.28), but the minimal important difference (MID) (8.7) was unmet. There were fewer flares with moisturisers (two studies, 87 participants, RR 0.40, 95% CI 0.23 to 0.70), time to flare was prolonged (median: 180 versus 30 days), and less topical corticosteroids were needed (two studies, 222 participants, MD -9.30 g, 95% CI -15.3 to -3.27). There was no statistically significant difference in adverse events (one study, 173 participants, risk ratio (RR) 15.34, 95% CI 0.90 to 261.64). Evidence for these outcomes was low quality.With Atopiclair (three studies), 174/232 participants experienced improvement in participant-assessed disease severity versus 27/158 allocated to vehicle (RR 4.51, 95% CI 2.19 to 9.29). Atopiclair decreased itching (four studies, 396 participants, MD -2.65, 95% CI -4.21 to -1.09) and achieved more frequent satisfaction (two studies, 248 participants, RR 2.14, 95% CI 1.58 to 2.89), fewer flares (three studies, 397 participants, RR 0.18, 95% CI 0.11 to 0.31), and lower EASI (four studies, 426 participants, MD -4.0, 95% CI -5.42 to -2.57), but MID (6.6) was unmet. The number of participants reporting adverse events was not statistically different (four studies, 430 participants, RR 1.03, 95% CI 0.79 to 1.33). Evidence for these outcomes was moderate quality.Participants reported skin improvement more frequently with urea-containing cream than placebo (one study, 129 participants, RR 1.28, 95% CI 1.06 to 1.53; low-quality evidence), with equal satisfaction between the two groups (one study, 38 participants, low-quality evidence). Urea-containing cream improved dryness (investigator-assessed) more frequently (one study, 128 participants, RR 1.40, 95% CI 1.14 to 1.71; moderate-quality evidence) with fewer flares (one study, 44 participants, RR 0.47, 95% CI 0.24 to 0.92; low-quality evidence), but more participants in this group reported adverse events (one study, 129 participants, RR 1.65, 95% CI 1.16 to 2.34; moderate-quality evidence).Three studies assessed glycerol-containing moisturiser versus vehicle or placebo. More participants in the glycerol group noticed skin improvement (one study, 134 participants, RR 1.22, 95% CI 1.01 to 1.48; moderate-quality evidence), and this group saw improved investigator-assessed SCORAD (one study, 249 participants, MD -2.20, 95% CI -3.44 to -0.96; high-quality evidence), but MID was unmet. Participant satisfaction was not addressed. The number of participants reporting adverse events was not statistically significant (two studies, 385 participants, RR 0.90, 95% CI 0.68 to 1.19; moderate-quality evidence).Four studies investigated oat-containing moisturisers versus no treatment or vehicle. No significant differences between groups were reported for participant-assessed disease severity (one study, 50 participants, RR 1.11, 95% CI 0.84 to 1.46; low-quality evidence), satisfaction (one study, 50 participants, RR 1.06, 95% CI 0.74 to 1.52; very low-quality evidence), and investigator-assessed disease severity (three studies, 272 participants, standardised mean difference (SMD) -0.23, 95% CI -0.66 to 0.21; low-quality evidence). In the oat group, there were fewer flares (one study, 43 participants, RR 0.31, 95% CI 0.12 to 0.7; low-quality evidence) and less topical corticosteroids needed (two studies, 222 participants, MD -9.30g, 95% CI 15.3 to -3.27; low-quality evidence), but more adverse events were reported (one study, 173 participants; Peto odds ratio (OR) 7.26, 95% CI 1.76 to 29.92; low-quality evidence).All moisturisers above were compared to placebo, vehicle, or no moisturiser. Participants considered moisturisers more effective in reducing eczema (five studies, 572 participants, RR 2.46, 95% CI 1.16 to 5.23; low-quality evidence) and itch (seven studies, 749 participants, SMD -1.10, 95% CI -1.83 to -0.38) than control. Participants in both treatment arms reported comparable satisfaction (three studies, 296 participants, RR 1.35, 95% CI 0.77 to 2.26; low-quality evidence). Moisturisers led to lower investigator-assessed disease severity (12 studies, 1281 participants, SMD -1.04, 95% CI -1.57 to -0.51; high-quality evidence) and fewer flares (six studies, 607 participants, RR 0.33, 95% CI 0.17 to 0.62; moderate-quality evidence), but there was no difference in adverse events (10 studies, 1275 participants, RR 1.03, 95% CI 0.82 to 1.30; moderate-quality evidence).Topical active treatment combined with moisturiser was more effective than active treatment alone in reducing investigator-assessed disease severity (three studies, 192 participants, SMD -0.87, 95% CI -1.17 to -0.57; moderate-quality evidence) and flares (one study, 105 participants, RR 0.43, 95% CI 0.20 to 0.93), and was preferred by participants (both low-quality evidence). There was no statistically significant difference in number of adverse events (one study, 125 participants, RR 0.39, 95% CI 0.13 to 1.19; very low-quality evidence). Participant-assessed disease severity was not addressed.

AUTHORS' CONCLUSIONS

Most moisturisers showed some beneficial effects, producing better results when used with active treatment, prolonging time to flare, and reducing the number of flares and amount of topical corticosteroids needed to achieve similar reductions in eczema severity. We did not find reliable evidence that one moisturiser is better than another.

A programme of research to set priorities and reduce uncertainties for the prevention and treatment of skin disease

Background

Skin diseases are very common and can have a large impact on the quality of life of patients and caregivers. This programme addressed four diseases: (1) eczema, (2) vitiligo, (3) squamous cell skin cancer (SCC) and (4) pyoderma gangrenosum (PG).

Objective

To set priorities and reduce uncertainties for the treatment and prevention of skin disease in our four chosen diseases.

Design

Mixed methods including eight systematic reviews, three prioritisation exercises, two pilot randomised controlled trials (RCTs), three feasibility studies, two core outcome initiatives, four funding proposals for national RCTs and one completed national RCT.

Setting

Secondary care, primary care and the general population.

Participants

Patients (and their caregivers) with eczema, vitiligo, SCC and PG, plus health-care professionals with an interest in skin disease.

Interventions

Our three intervention studies included (1) barrier enhancement using emollients from birth to prevent eczema (pilot RCT); (2) handheld narrowband ultraviolet light B therapy for treating vitiligo (pilot RCT); and (3) oral ciclosporin (Neoral®, Novartis Pharmaceuticals) compared with oral prednisolone for managing PG (pragmatic national RCT).

Results

Systematic reviews included two overarching systematic reviews of RCTs of treatments for eczema and vitiligo, an umbrella review of systematic reviews of interventions for the prevention of eczema, two reviews of treatments for SCC (one included RCTs and the second included observational studies), and three reviews of outcome measures and outcome reporting. Three prioritisation partnership exercises identified 26 priority areas for future research in eczema, vitiligo and SCC. Two international consensus initiatives identified four core domains for future eczema trials and seven core domains for vitiligo trials. Two pilot RCTs and three feasibility studies critically informed development of four trial proposals for external funding, three of which are now funded and one is pending consideration by funders. Our pragmatic RCT tested the two commonly used systemic treatments for PG (prednisolone vs. ciclosporin) and found no difference in their clinical effectiveness or cost-effectiveness. Both drugs showed limited benefit. Only half of the participants’ ulcers had healed by 6 months. For those with healed ulcers, recurrence was common (30%). Different side effect profiles were noted for each drug, which can inform clinical decisions on an individual patient basis. Three researchers were trained to PhD level and a dermatology patient panel was established to ensure patient involvement in all aspects of the programme.

Conclusions

Findings from this programme of work have already informed clinical guidelines and patient information resources. Feasibility studies have ensured that large national pragmatic trials will now be conducted on important areas of treatment uncertainty that address the needs of patients and the NHS. There is scope for considerable improvement in terms of trial design, conduct and reporting for RCTs of skin disease, which can be improved through wider collaboration, registration of trial protocols and complete reporting and international consensus over core outcome sets. Three national trials have now been funded as a result of this work. Two international initiatives to establish how best to measure the core outcome domains for eczema and vitiligo are ongoing.

Trial registration

Current Controlled Trials Barrier Enhancement for Eczema Prevention (BEEP) (ISRCTN84854178 and NCT01142999), Study of Treatments fOr Pyoderma GAngrenosum Patients (STOP GAP) (ISRCTN35898459) and Hand Held NB-UVB for Early or Focal Vitiligo at Home (HI-Light Pilot Trial) (NCT01478945).

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 4, No. 18. See the NIHR Journals Library website for further project information.