Urea uptake enhances barrier function and antimicrobial defense in humans by regulating epidermal gene expression

Micro/Nanomotor-Driven Intelligent Targeted Delivery Systems: Dynamics Sources and Frontier Applications

Micro/nanomotors represent a promising class of drug delivery carriers capable of converting surrounding chemical or external energy into mechanical power, enabling autonomous movement. Their distinct autonomous propulsive force distinguishes them from other carriers, offering significant potential for enhancing drug penetration across cellular and tissue barriers. A comprehensive understanding of micro/nanomotor dynamics with various power sources is crucial to facilitate their transition from proof-of-concept to clinical application. In this review, micro/nanomotors are categorized into three classes based on their energy sources: endogenously stimulated, exogenously stimulated, and live cell-driven. The review summarizes the mechanisms governing micro/nanomotor movements under these energy sources and explores factors influencing autonomous motion. Furthermore, it discusses methods for controlling micro/nanomotor movement, encompassing aspects related to their structure, composition, and environmental factors. The remarkable propulsive force exhibited by micro/nanomotors makes them valuable for significant biomedical applications, including tumor therapy, bio-detection, bacterial infection therapy, inflammation therapy, gastrointestinal disease therapy, and environmental remediation. Finally, the review addresses the challenges and prospects for the application of micro/nanomotors. Overall, this review emphasizes the transformative potential of micro/nanomotors in overcoming biological barriers and enhancing therapeutic efficacy, highlighting their promising clinical applications across various biomedical fields.

Mechanisms of penetration and diffusion of drugs and cosmetic actives across the human Stratum corneum

Based on the structure of the Stratum corneum (SC) the potential penetration/diffusion pathways of drugs and cosmetic actives through the SC are presented and discussed. The well-known lipophilic pathway across the SC is presented and relevant examples are used to show that highly lipophilic molecules such as glucocorticoids, coenzyme Q10 etc. are accumulated in the SC and penetrate into the inner liquid like layer of the SC lipid bilayer by lateral diffusion. The diffusion into and across the SC of highly hydrophilic drugs and active substances such as urea, amino acids and peptides is still under discussion. Another diffusion pathway for the highly hydrophilic molecules via the corneocytes and the corneodesmosomes is presented and discussed, the corneocytary diffusion pathway.

Delivery of small hydrophilic molecules across the stratum corneum: Identification of model systems and parameters to study topical delivery of free amino acids

Free amino acids (FAAs) constitute the largest component (∼40 %) of the so-called natural moisturizing factors of the skin. Their level declines in dry skin conditions and one strategy to overcome this problem may involve the topical delivery of FAAs through appropriate strategy. The objective of the present study was therefore to identify alternative skin models and study the corneocyte-water partition coefficients (KCOR/W) and permeation coefficient (KP) of 18 FAAs. The KCOR/W was studied using standard protocols and the permeation studies were conducted using Franz diffusion cell. The results indicate that the FAAs have high partitioning behavior to the corneocytes. The KCOR/W values of the human COR and that of pig ear skin were better correlated with each other than that of keratin isolated from chicken feathers. The presence of lipid in the stratum corneum (SC), initial concentration of the FAAs, and permeation enhancers affect the KCOR/W. The FAAs have low permeation into the SC which suggests the need for permeation enhancers in designing dosage form containing these compounds. Even though the investigated mathematical models show good prediction of the Kp values, better prediction could be obtained by considering factors such as the possible entrapment of the FAAs by the CORs.

Randomized Double-blind Cost-effectiveness Comparison of Two 10% Urea Creams in Patients with Diabetic Foot Syndrome

OBJECTIVE

To evaluate the cost-effectiveness of two 10% urea creams in patients with diabetic foot syndrome.

METHODS

This was a prospective, longitudinal, single-center, randomized, double-blind, prospective clinical trial that evaluated the skin quality of 20 feet belonging to 10 patients with diabetic foot syndrome after the application of two 10% urea creams purchased from pharmacies and supermarkets.

RESULTS

At follow-up, 19 (95%) of the participants' feet showed improved skin quality, irrespective of the cream applied. On visual inspection, participants had a decreased presence of xerosis, hyperkeratosis, and preulcerative signs such as subkeratotic bruising and areas of redness on the dorsum of the toes. At the 3-month follow-up, nine (90%) of the participants stated that they had continued to apply the cream as a method of self-management to prevent complications.

CONCLUSIONS

Creams containing 10% urea purchased in supermarkets improve foot skin quality in patients with diabetic foot syndrome, regardless of their cost. Based on these findings, the authors recommend creams containing 10% urea as a self-management tool for patients with diabetic foot syndrome.

Overview of popular cosmeceuticals in dermatology

The eternal pursuit to prevent ageing and maintain a youthful appearance has resulted in a rapidly expanding cosmeceutical industry. Cosmeceutical products, particularly of natural origin, are in high demand due to claims of efficacy for signs of ageing and other skin conditions. Consumers often include cosmeceutical products in their skin care regime as they are readily available, and a more affordable option compared to prescription products. However, many cosmeceutical ingredients lack clinical evidence regarding their efficacy and safety as these products are not regulated by the U.S. Food and Drug Administration. This review provides a brief overview of several popular cosmeceutical ingredients with regards to their potential indications, targets and mechanisms of action.

Effects of a leave-on product on the strength of the dermoepidermal junction: An exploratory, intraindividual, randomized controlled trial in older adults with dry skin

Background and Aims

Skin aging is associated with dry skin and a decrease of the strength of the dermoepidermal adhesion, which increases the risk for lacerations (skin tears). Application of leave-on products improves dry skin and seems to reduce skin tear incidence. The aim of this study was to measure the effects of a humectant containing leave-on product on the strength of the dermoepidermal junction in older adult participants with dry skin.

Methods

A randomized controlled trial using a split body design was conducted. One forearm was randomly selected and treated with a lipophilic leave-on product containing 5% urea for 8 weeks. The other forearm was the control. The parameters stratum corneum hydration (SCH), transepidermal water loss, pH, roughness, epidermal thickness and skin stiffness were measured at the baseline, Weeks 4 and 8. At Week 8, suction blisters were created and time to blistering was measured. Blister roofs and interstitial fluid were analyzed for Interleukin-1α, 6 and 8.

Results

Twelve participants were included. After 8 weeks treatment, SCH was higher (median difference 11.6 AU), and the overall dry skin score (median difference -1) and median roughness (Rz difference -12.2 µm) were lower compared to the control arms. The median group difference for Interleukin-1α was -452 fg/µg total protein (TP) in the blister roofs and -2.2 fg/µg TP in the blister fluids. The median time to blister formation was 7.7 min higher compared to the control arms.

Conclusion

The regular application of humectant containing leave-on products improves dry skin and seems to lower inflammation and contribute to the strengthening of the dermoepidermal adhesion. This partly explains how the use of topical leave-on products helps to prevent skin tears.

0.5-5% Supramolecular Salicylic Acid Hydrogel is Safe for Long-Term Topical Application and Improves the Expression of Genes Related to Skin Barrier Homeostasis in Mice Models

Background

As a keratolytic, salicylic acid (SA) can be topically applied in various formulations and doses in dermatology. Supramolecular SA hydrogel, a new SA formulation with higher bioavailability, is developed and commercially available nowadays. However, there still remain concerns that the long-term and continual application of SA at low concentrations may jeopardize the cutaneous barrier properties.

Aim of the Study

To reveal the long-term effects of 0.5-5% supramolecular SA hydrogel on the skin barrier in normal mice models.

Materials and Methods

The 0.5%, 1%, 2%, and 5% supramolecular SA hydrogel or hydrogel vehicle without SA was applied to mice's shaved dorsal skin once per day respectively. Tissue samples of the dorsal skin were harvested on day 14 and 28 of the serial application of SA for histopathological observation and transcriptomic analysis.

Results

Following topical supramolecular SA hydrogel therapy with various concentrations of SA (0.5%, 1%, 2%, and 5%) for 14 days and 28 days, there were no obvious macroscopic signs of impaired cutaneous health and no inflammatory or degenerative abnormalities were observed in histological results. Additionally, the transcriptomic analysis revealed that on day 14, SA dramatically altered the expression of genes related to the extracellular matrix structural constituent. And on day 28, SA regulated gene expression profiles of keratinization, cornified envelope, and lipid metabolism remarkably. Furthermore, the expression of skin barrier related genes was significantly elevated after the application of SA based on RNA-seq results, and this is likely to be associated with the PPAR signaling pathway according to the enrichment analysis.

Conclusion

Our findings demonstrated that the sustained topical administration of the 0.5-5% supramolecular SA hydrogel for up to 28 days did no harm to normal murine skin and upregulated the expression of genes related to the epidermal barrier.

The foot in diabetes - a reminder of an ever-present risk

The term 'diabetic foot disease' (DFD) often signifies the presence of foot ulceration and infection, but one must also be wary of the rarer occurrence of Charcot foot disease. The worldwide prevalence of DFD is 6.3% (95%CI: 5.4-7.3%). Foot complications present a major challenge to both patients and healthcare systems, with increased rates of hospitalisation and an almost trebled 5-year mortality. The Charcot foot often occurs in patients with long-standing diabetes, presenting as an inflamed or swollen foot or ankle, following unrecognised minor trauma. This review focuses on the prevention and early identification of the 'at-risk' foot. DFD is best managed by a multi-disciplinary foot clinic team consisting of podiatrists and healthcare professionals. This ensures a combination of expertise and provision of a multi-faceted evidence-based treatment plan. Current research using endothelial progenitor cells (EPC) and mesenchymal stem cells (MSC) offers a new dimension in wound management.

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.

The Effects of Mucopolysaccharide Polysulfate on Steroid-Induced Tight Junction Barrier Dysfunction in Human Epidermal Keratinocytes and a 3D Skin Model

INTRODUCTION

The long-term use of topical corticosteroids (TCS) is associated with side effects such as skin atrophy and barrier deterioration. Moisturizers, such as mucopolysaccharide polysulfate (MPS), have been reported to prevent relapses in atopic dermatitis (AD) when used in combination with TCS. However, the mechanisms underlying the positive effects of MPS in combination with TCS in AD are poorly understood. In the present study, we investigated the effects of MPS in combination with clobetasol 17-propionate (CP) on tight junction (TJ) barrier function in human epidermal keratinocytes (HEKa) and 3D skin models.

METHODS

The expression of claudin-1, which is crucial for TJ barrier function in keratinocytes, and transepithelial electrical resistance (TEER) was measured in CP-treated human keratinocytes incubated with and without MPS. A TJ permeability assay, using Sulfo-NHS-Biotin as a tracer, was also conducted in a 3D skin model.

RESULTS

CP reduced claudin-1 expression and TEER in human keratinocytes, whereas MPS inhibited these CP-induced effects. Moreover, MPS inhibited the increase in CP-induced TJ permeability in a 3D skin model.

CONCLUSION

The present study demonstrated that MPS improved TJ barrier impairment induced by CP. The improvement of TJ barrier function may partially be responsible for the delayed relapse of AD induced by the combination of MPS and TCS.

Efficacy and tolerability of a repairing moisturizing cream containing amino-inositole and urea 10% in adults with chronic eczematous dermatitis of the hands

BACKGROUND

Patients suffering from eczematous dermatitis always required moisturizing cream as a background therapy with the aim to reduce flares and minimize steroids use. The term emollients plus (EP) refers to a topical formulations with vehicle-type substances and additional active, non-medicated substances. We have conducted a study with a topical emollient containing urea 10% and amino-inositole on 20 patients affected from chronic eczematous dermatitis. Primary outcomes were to evaluate effectiveness, in term of Investigator Global Assessment (IGA), and tolerability of EP. Secondary aims included the comparison of NRS (numerical rating scale) itch and NRS-pain, DLQI (Dermatological Life Quality Index) between day one and day 28 and to evaluate the characteristics of EP.

METHODS

Subjects were instructed to apply the EP twice daily for 4 weeks on affected skin and use a soft soap while not to put any other topical or systemic product. Statistical analysis was conducted through the test t-Student by comparing IGA, itch-NRS, pain-NRS and DLQI at time 0 and day 28.

RESULTS

High statistically significant difference (P=0.0038) between IGA value at T0 and T4 has been demonstrated as for itch and pain (respectively P=0.0203 and P=0.0146). Almost all the patients (89.5%) have declared a good or better tolerability of EP. Two patients did not complete the study.

CONCLUSIONS

Patients with chronic eczema could often resolve the dermatitis with the correct choice of emollient without steroids use, especially if it is an EP.

Transport Characteristics of Aquaporins

Aquaporins (AQP) are a class of the integral membrane proteins. The main physiological function of AQPs is to facilitate the water transport across plasma membrane of cells. However, the transport of various kinds of small molecules by AQPs is an interesting topic. Studies using in vitro cell models have found that AQPs mediated transport of small molecules, including glycerol, urea, carbamides, polyols, purines, pyrimidines and monocarboxylates, and gases such as CO2, NO, NH3, H2O2 and O2, although the high intrinsic membrane permeabilities for these gases make aquaporin-facilitated transport not dominant in physiological mechanism. AQPs are also considered to transport silicon, antimonite, arsenite and some ions; however, most data about transport characteristics of AQPs are derived from in vitro experiments. The physiological significance of AQPs that are permeable to various small molecules is necessary to be determined by in vivo experiments. This chapter will provide information about the transport characteristics of AQPs.

Aquaporins in Skin

The skin is the largest organ of our body and plays a protective role against the external environment. The skin functions as a mechanical and water permeability barrier, assisting with thermoregulation and defending our body against a variety of stresses such as ultraviolet radiation, microbial infection, physical injuries, and chemical hazards. The structure of the skin consists of three main layers: the hypodermis, the dermis, and the epidermis. Aquaporins (AQPs) are a family of integral membrane proteins whose function is to regulate intracellular fluid hemostasis by facilitating the transportation of water, and in some cases small molecules, across the cell membranes. Up to six different AQPs (AQP1, 3, 5, 7, 9, and 10) are expressed in a variety of cell types in the skin. The AQP family plays an important role in these various locations, contributing to many key functions of the skin including hydration, wound healing, and immune responses. The involvement of different aquaporin family members in skin is discussed.

The Use of Urea Cream for Hand Eczema and Urea Foam for Seborrheic Dermatitis and Psoriasiform Dermatoses of the Scalp

PURPOSE

Urea as an ingredient in topical skin applications can aid skin integrity and hydration and have keratolytic, anti-fungal, anti-bacterial, and anti-pruritic effects. Skin conditions that urea-containing formulations have been utilized to treat include hand eczema/dermatitis, seborrheic dermatitis and psoriasiform dermatoses of the scalp. Two monocentric, simple blind, observational studies were carried out in healthy participants to examine the efficacy and safety of two urea-containing products in these skin conditions.

PATIENTS AND METHODS

Study 1 tested the actions of a commercially available 30% urea topical cream on hand eczema. The product was applied ≥2/day for 28 ±2 days. Transepidermal water loss, skin redness, skin hydration, and participant ratings of efficacy and qualities were assessed prior to first product application and on days 14 and 29. Study 2 tested the actions of a commercially available foaming product containing 10% urea on seborrheic dermatitis and scalp psoriasiform dermatoses. The product was applied ≥2/day for 28 ±2 days. Desquamation index and surface occupied by squames, analysis of extracted squames, microscopic assessment of scalp photos and participant ratings of product efficacy and qualities was carried out prior to first product application and on days 14 and 29.

RESULTS

In Study 1 (n = 20 females), results showed a significant (p < 0.05) decrease in transepidermal water loss, with an increase in hydration level of the upper skin layers, and a decrease in skin redness. In Study 2 (n = 13 females, 7 males), product use led to significant (p < 0.05) decreases in desquamation measures and dryness. In both studies, the majority of participants "agreed" or "slightly agreed" that the product had good efficacy and was easy to apply. No adverse reactions were reported.

CONCLUSION

These findings point to the utility of urea in topically applied vehicles for hand eczema, seborrheic dermatitis, and psoriasiform dermatoses.

The use of urea for skin barrier correction

The review summarizes information about the main causes and pathogenesis of xerosis cutis as one of the conditions indicating a violation of the epidermal barrier. Xerosis cutis is a clinical sign of a decrease in the amount and/or quality of lipids and/or hydrophilic substances in the stratum corneum of the epidermis. The modern approach to the treatment of dermatoses accompanied by violations of the epidermal barrier includes basic moisturizers. Urea not only moisturizes the skin. It is involved in the regulation of barrier function and antimicrobial protection. It is a low-molecular regulator of protein synthesis in keratinocytes, such as filaggrin, loricrin, involucrin and transglutaminase 1, cathelicidin, beta-defensin-2, water and urea carrier proteins into the cell, as well as proteins that promote the synthesis of intercellular matrix lipids. The main dermatotropic pharmacological effects of urea (hydration of the epidermis, strengthening of the barrier function of the skin, keratolytic effect, increased penetration of drugs into the skin) have been used in dermatological practice for many years. External agents with urea are used to treat skin diseases accompanied by dryness and excessive keratinization, to correct the deformation of nail plates of various genesis, to facilitate the local penetration of medicines. The use of topical UrocrEM5, UrocrEM10, Uroderm ointments containing 5%, 10% and 30% urea, respectively, is effective and safe.

Skin Care Product Rich in Antioxidants and Anti-Inflammatory Natural Compounds Reduces Itching and Inflammation in the Skin of Atopic Dermatitis Patients

The atopic dermatitis (AD) complex pathogenesis mechanism reveals marked changes of certain signaling factors as well as some morphological alterations in the epidermis. Reduced resilience against environmental factors and oxidative stress often makes the treatment with corticosteroids or tacrolismus ointments indispensable. In view of the correlation between oxidative stress and AD pathological factors, antioxidants can be incorporated into AD management strategies. This study investigates a curly kale, apple and green tea-containing natural extract rich in antioxidants for its effects on signaling inflammatory molecules and skin barrier enhancement in human epidermal keratinocytes- (NHEKs) based cell assays. Furthermore, the skin penetration on porcine ears was measured ex vivo using Raman micro spectroscopy. Finally, in a double-blind half-side, placebo-controlled clinical study, the effects of a formulation containing this extract were analyzed for the influence of lesion severity, epidermal barrier function, and pruritus in mild to moderately AD patients. Summarizing our results: The extract reduces expression of inflammatory cytokines in keratinocytes and increases barrier-related molecules. The verum formulation with a very high antioxidant capacity used in AD patients with mild to moderate lesions reduces itching, local SCORAD, and improves barrier function and the hydration of skin lesions.

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.

Potential Mechanisms of the Sparing of Atopic Dermatitis in the Diaper Region: A Scoping Review

Atopic dermatitis (AD) is a chronic, inflammatory skin condition commonly affecting infants with notable sparing of the diaper region. Though sources anecdotally attribute this sparing to the physical barrier formed by the diaper and the subsequent retention of moisture, urine, sweat and feces, no studies have formally investigated the factors contributing to this sparing phenomenon. We performed a scoping literature review to investigate the factors involved in sparing of AD in the diaper region, namely humidity, scratching, urine, sweat, feces, and microbiome composition. A total of 130 papers met the inclusion criteria, and extracted data were analyzed in an iterative manner. Increased local humidity facilitates protective changes at the cellular level and offsets transepidermal water loss. Exposure to urea from both sweat and urine may contribute to improved moisturization of the skin through its natural humectant properties and ability to modulate gene expression. Introduction of flora in feces contributes to the generation of protective immune responses and outcompetes growth of pathogens such as Staphylococcus aureus. Finally, diapers physically prevent scratching, which directly interrupts the itch-scratch cycle classically implicated in AD. Our study reviews factors that may contribute to the sparing of AD in the diaper region in infants. A limitation to our findings is that the studies reviewed here explore the impacts of these factors on AD broadly, and not explicitly in the diaper region. Additional studies investigating this may further our understanding of AD pathogenesis and contribute to the development of effective therapeutics.

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.

The impact of external factors on psoriasis

Psoriasis is one of the most common chronic inflammatory skin diseases, constituting a significant health and socioeconomic problem. Despite numerous therapeutic options, the results of treatment very often remain insufficient. It is extremely important to remember that many external factors impact the effectiveness of therapy. This article discusses the importance of emollients in therapy and the influence of infectious agents and injuries on the course of psoriasis. Understanding the above-mentioned factors in the treatment of psoriasis is critical to achieve satisfactory therapeutic effects.

Beyond Ca2+ signalling: the role of TRPV3 in the transport of NH4. Pflugers Arch 2021;473:1859-1884. [PMID: 34664138 PMCID: PMC8599221 DOI: 10.1007/s00424-021-02616-0]

Mutations of TRPV3 lead to severe dermal hyperkeratosis in Olmsted syndrome, but whether the mutants are trafficked to the cell membrane or not is controversial. Even less is known about TRPV3 function in intestinal epithelia, although research on ruminants and pigs suggests an involvement in the uptake of NH₄⁺. It was the purpose of this study to measure the permeability of the human homologue (hTRPV3) to NH₄⁺, to localize hTRPV3 in human skin equivalents, and to investigate trafficking of the Olmsted mutant G573S. Immunoblotting and immunostaining verified the successful expression of hTRPV3 in HEK-293 cells and Xenopus oocytes with trafficking to the cell membrane. Human skin equivalents showed distinct staining of the apical membrane of the top layer of keratinocytes with cytosolic staining in the middle layers. Experiments with pH-sensitive microelectrodes on Xenopus oocytes demonstrated that acidification by NH₄⁺ was significantly greater when hTRPV3 was expressed. Single-channel measurements showed larger conductances in overexpressing Xenopus oocytes than in controls. In whole-cell experiments on HEK-293 cells, both enantiomers of menthol stimulated influx of NH₄⁺ in hTRPV3 expressing cells, but not in controls. Expression of the mutant G573S greatly reduced cell viability with partial rescue via ruthenium red. Immunofluorescence confirmed cytosolic expression, with membrane staining observed in a very small number of cells. We suggest that expression of TRPV3 by epithelia may have implications not just for Ca²⁺ signalling, but also for nitrogen metabolism. Models suggesting how influx of NH₄⁺ via TRPV3 might stimulate skin cornification or intestinal NH₄⁺ transport are discussed.

A Biomimetic Combination of Actives Enhances Skin Hydration and Barrier Function via Modulation of Gene Expression: Results of Two Double-Blind, Vehicle-Controlled Clinical Studies

INTRODUCTION

Xerosis cutis is characterized by a decreased stratum corneum (SC) hydration and an impaired skin barrier function. Urea, the most prevalent natural moisturizing factor (NMF), is currently considered the gold standard. Its efficacy can further be increased by combining urea with other NMF and skin barrier lipids (SBLs).

OBJECTIVE

We set out to evaluate physiological effects of a novel functional moisturizer containing 10% urea, additional NMF components, and a combination of SBLs on skin hydration and skin barrier integrity on a cellular and phenotypic level in female volunteers suffering from xerosis.

METHODS

Two double-blind, vehicle-controlled clinical studies were conducted. In the first study, 44 female subjects having very dry body skin applied the moisturizer or its vehicle twice daily to their volar forearms. Twenty-four hours after a single product application as well as 24 h after 2 weeks of treatment, SC hydration was measured by corneometry. Skin barrier function was assessed by transepidermal water loss 24 h and 48 h after 2 weeks of regular use. Twenty-four hours after 2 weeks of application, skin tape stripping was performed, and urea content was determined in the 3rd strip by means of high-performance liquid chromatography/tandem mass spectrometry. In the second study, 22 women with self-reported very dry skin applied the moisturizer or vehicle twice daily to their volar forearms for 2 weeks. Then, suction blister samples were obtained for gene expression analysis using RT-PCR.

RESULTS

Application of the actives led to significantly improved skin hydration and barrier function at all points in time. Compared to the vehicle, application of the moisturizer for 2 weeks resulted in a significant increase in SC urea content. Relative gene expression data revealed significant upregulation of genes associated with skin barrier function, hydration, differentiation, and lipid metabolism compared to the vehicle-treated area.

CONCLUSIONS

Overall, our data demonstrate that the functional moisturizer provides an adequate bioavailability of urea and a beneficial biophysical impact on xerotic skin. Topical treatment with a combination of urea and additional NMF as well as SBL can modify mRNA expression of important epidermal genes stimulating cellular processes and functions. The well-tolerated novel functional moisturizer stimulates molecular mechanisms involved in skin hydration and barrier function and is a profoundly effective treatment option for xerosis cutis.

Urea in Dermatology: A Review of its Emollient, Moisturizing, Keratolytic, Skin Barrier Enhancing and Antimicrobial Properties

Urea is a hygroscopic molecule (capable of absorbing water) present in the epidermis as a component of the natural moisturizing factor (NMF) and is essential for the adequate hydration and integrity of the stratum corneum. Urea improves skin barrier function including antimicrobial defense by regulating gene expression in keratinocytes relevant for their differentiation and antimicrobial peptide production. It also plays a fundamental role in regulating keratinocyte proliferation. One of the first uses of urea in modern medicine was the topical treatment of wounds due to its proteolytic and antibacterial properties. At present, urea is widely used in dermatology to improve skin barrier function and as one of the most common moisturizers and keratolytic agents. Urea-containing formulations are available in diverse formulations and concentrations. Multiple clinical trials on the use of urea-containing formulations have shown significant clinical improvement in many of the dermatosis presenting with scaly and dry skin such as atopic dermatitis, ichthyosis, xerosis, seborrheic dermatitis and psoriasis, among others. Furthermore, urea can increase skin penetration and optimize the action of topical drugs. Urea-based products are well tolerated; their side effects are mild and are more frequent at high concentration. Here, we present a review of the use of urea in dermatology, discussing its mechanism of action, safety profile and frequent indications.

Biomarkers for Ehlers-Danlos Syndromes: There Is a Role?

Ehlers-Danlos syndromes (EDS) are an inherited heterogeneous group of connective tissue disorders characterized by an abnormal collagen synthesis affecting skin, ligaments, joints, blood vessels, and other organs. It is one of the oldest known causes of bruising and bleeding, and it was described first by Hippocrates in 400 BC. In the last years, multiple gene variants involved in the pathogenesis of specific EDS subtypes have been identified; moreover, new clinical diagnostic criteria have been established. New classification models have also been studied in order to differentiate overlapping conditions. Moreover, EDS shares many characteristics with other similar disorders. Although distinguishing between these seemingly identical conditions is difficult, it is essential in ensuring proper patient care. Currently, there are many genetic and molecular studies underway to clarify the etiology of some variants of EDS. However, the genetic basis of the hypermobile type of EDS (hEDS) is still unknown. In this review, we focused on the study of two of the most common forms of EDS—classic and hypermobile—by trying to identify possible biomarkers that could be of great help to confirm patients’ diagnosis and their follow up.

Metformin inhibits MAPK signaling and rescues pancreatic aquaporin 7 expression to induce insulin secretion in type 2 diabetes mellitus

Metformin is the first-line antidiabetic agent for type 2 diabetes mellitus (T2DM) treatment. Although accumulated evidence has shed light on the consequences of metformin action, the precise mechanisms of its action, especially in the pancreas, are not fully understood. Aquaporin 7 (AQP7) acts as a critical regulator of intraislet glycerol content, which is necessary for insulin production and secretion. The aim of this study was to investigate the effects of different doses of metformin on AQP7 expression and explore the possible mechanism of its protective effects in the pancreatic islets. We used an in vivo model of high-fat diet in streptozocin-induced diabetic rats and an in vitro model of rat pancreatic β-cells (INS-1 cells) damaged by hyperglycemia and hyperlipidemia. Our data showed that AQP7 expression levels were decreased, whereas p38 and JNK mitogen-activated protein kinases (MAPKs) were activated in vivo and in vitro in response to hyperglycemia and hyperlipidemia. T2DM rats treated with metformin demonstrated a reduction in blood glucose levels and increased regeneration of pancreatic β-cells. In addition, metformin upregulated AQP7 expression as well as inhibited activation of p38 and JNK MAPKs both in vivo and in vitro. Overexpression of AQP7 increased glycerol influx into INS-1 cells, whereas inhibition of AQP7 reduced glycerol influx, thereby decreasing subsequent insulin secretion. Our findings demonstrate a new mechanism by which metformin suppresses the p38 and JNK pathways, thereby upregulating pancreatic AQP7 expression and promoting glycerol influx into pancreatic β-cells and subsequent insulin secretion in T2DM.

Antimicrobial peptides and proteins: Interaction with the skin microbiota

The cutaneous microbiota comprises all living skin microorganisms. There is increasing evidence that the microbiota plays a crucial role in skin homeostasis. Accordingly, a dysbiosis of the microbiota may trigger cutaneous inflammation. The need for a balanced microbiota requires specific regulatory mechanisms that control and shape the microbiota. In this review, we highlight the present knowledge suggesting that antimicrobial peptides (AMPs) may exert a substantial influence on the microbiota by controlling their growth. This is supported by own data showing the differential influence of principal skin-derived AMPs on commensal staphylococci. Vice versa, we also illuminate how the cutaneous microbiota interacts with skin-derived AMPs by modulating AMP expression and how microbiota members protect themselves from the antimicrobial activity of AMPs. Taken together, the current picture suggests that a fine-tuned and well-balanced AMP-microbiota interplay on the skin surface may be crucial for skin health.

[Influence of an adjuvant treatment with an emollient containing 10 % urea, ceramides, glycerin und glyceryl glucoside in patients with psoriasis vulgaris]

BACKGROUND

Guidelines generally recommend an adjuvant treatment with emollients for patients suffering from psoriasis. However evidence for this purpose is limited.

PATIENTS AND METHODS

We performed a prospective observational study with an emollient containing 10% urea, ceramides, glycerin and glyceryl glucoside in patients suffering from mild to moderate psoriasis. The patients had to be stable for at least 12 weeks on prior antipsoriatic therapy including topical therapy, systemic treatment or phototherapy which was continued during the trial.

RESULTS

A 4-week daily application of the emollient resulted in significant improvement regarding quality of life (measured by DLQI, Dermatology Life Quality Index) and clinical outcome (measured by local PASI, Psoriasis Area and Severity Index) among the treated patients.

CONCLUSION

The trial results show that a daily adjuvant treatment with emollients can support a basic antipsoriatic therapy both in aspects of clinical efficacy and quality of life in mild to moderate patients suffering from psoriasis.

Skin aquaporins as druggable targets: Promoting health by addressing the disease

Skin is the most vulnerable organ of the human body since it is the first line of defense, covering the entire external body surface. Additionally, skin has a critical role in thermoregulation, sensation, immunological surveillance, and biochemical processes such as Vitamin D₃ production by ultraviolet irradiation. The ability of the skin layers and resident cells to maintain skin physiology, such as hydration, regulation of keratinocytes proliferation and differentiation and wound healing, is supported by key proteins such as aquaporins (AQPs) that facilitate the movements of water and small neutral solutes across membranes. Various AQP isoforms have been detected in different skin-resident cells where they perform specific roles, and their dysregulation has been associated with several skin pathologies. This review summarizes the current knowledge of AQPs involvement in skin physiology and pathology, highlighting their potential as druggable targets for the treatment of skin disorders.

New Treatments for Atopic Dermatitis Targeting Skin Barrier Repair via the Regulation of FLG Expression

Atopic dermatitis (AD) is one of the most common chronic, inflammatory skin disorders with a complex etiology and a broad spectrum of clinical phenotypes. Despite its high prevalence and effect on the quality of life, safe and effective systemic therapies approved for long-term management of AD are limited. A better understanding of the pathogenesis of atopic dermatitis in recent years has contributed to the development of new therapeutic approaches that target specific pathophysiological pathways. Skin barrier dysfunction and immunological abnormalities are critical in the pathogenesis of AD. Recently, the importance of the downregulation of epidermal differentiation complex (EDC) molecules caused by external and internal stimuli has been extensively emphasized. The purpose of this review is to discuss the innovations in the therapy of atopic dermatitis, including biologics, small molecule therapies, and other drugs by highlighting regulatory mechanisms of skin barrier-related molecules, such as filaggrin (FLG) as a crucial pathway implicated in AD pathogenesis.

Mode of action of urea

Urea is a major component of many daily skincare products which is widely used. Its role in the treatment of, for example atopic skin, atopic eczema, psoriasis and ichthyosis, is undisputed. However, the mode of action of urea is partly still elusive and goes far beyond its assumed passive role. This article shall elucidate biophysical characteristics and properties of molecular biology that explain how urea affects healthy skin and exerts efficacy in various skin diseases. Knowledge about the mode of action of urea enables physicians to better understandthe appropriate use of urea in clinical routine.

Atopic dermatitis epidemiology and unmet need in the United Kingdom

Atopic dermatitis (AD), also known as atopic eczema, is a chronic inflammatory skin condition associated with a significant health-related and socioeconomic burden, and is characterized by intense itch, disruption of the skin barrier, and upregulation of type 2-mediated immune responses. The United Kingdom (UK) has a high prevalence of AD, affecting 11-20% of children and 5-10% of adults. Approximately 2% of all cases of childhood AD in the UK are severe. Despite this, most AD treatments are performed at home, with little contact with healthcare providers or services. Here, we discuss the course of AD, treatment practices, and unmet need in the UK. Although the underlying etiology of the disease is still emerging, AD is currently attributed to skin barrier dysfunction and altered inflammatory responses. Management of AD focuses on avoiding triggers, improving skin hydration, managing exacerbating factors, and reducing inflammation through topical and systemic immunosuppressants. However, there is a significant unmet need to improve the overall management of AD and help patients gain control of their disease through safe and effective treatments. Approaches that target individual inflammatory pathways (e.g. dupilumab, anti-interleukin (IL)-4 receptor α) are emerging and likely to provide further therapeutic opportunities for patient benefit.

Clinical evidences of urea at medium concentration

Urea-based topical compounds at medium concentrations (15%-30%) represent useful dermatological agents for their humectant and keratolytic effects by enhancing stratum corneum hydration and by loosening epidermal keratin, respectively. The aim of this paper is to review the clinical evidences of the use of 15%-30% urea as single topical agent. Although limited evidence supports the use of these concentrations of urea in skin disorders characterised by xerosis and hyperkeratosis, in clinical practice they are largely used especially in xerosis of limited skin areas, in which the side effects are tolerable, or hyperkeratosis involving large or more sensitive (eg, face, genital region, etc) areas, in which higher concentration may be irritant. In addition, urea at medium concentrations is used in combination with other substances including topical antifungals as penetration enhancer.

History of urea as a dermatological agent in clinical practice

Urea, also known as carbamide, is a polar, hygroscopic molecule produced by the human body that was first discovered in urine in 1773 by the French chemist Hilaire Rouelle and was artificially synthesised from inorganic precursors in 1828 by the German chemist Friedrich Wöhler. The importance of urea in dermatology is twofold: it primarily has a physiological key role for the maintenance of skin hydration, and it secondarily has been used for more than a century in different topical preparation and concentration in various skin conditions. One of the first uses of urea was the topical treatment of wounds because of its antibacterial and proteolytic properties. Since the second part of the 20th century, urea became one of the most common moisturisers and keratolytic agents, useful for the treatment of xerosis, atopic dermatitis, ichthyosis and psoriasis.

Hair Follicle Targeting and Dermal Drug Delivery with Curcumin Drug Nanocrystals-Essential Influence of Excipients

Many active pharmaceutical ingredients (API) possess poor aqueous solubility and thus lead to poor bioavailability upon oral administration and topical application. Nanocrystals have a well-established, universal formulation approach to overcome poor solubility. Various nanocrystal-based products have entered the market for oral application. However, their use in dermal formulations is relatively novel. Previous studies confirmed that nanocrystals are a superior formulation principle to improve the dermal penetration of poorly soluble API. Other studies showed that nanocrystals can also be used to target the hair follicles where they create a drug depot, enabling long acting drug therapy with only one application. Very recent studies show that also the vehicle in which the nanocrystals are incorporated can have a tremendous influence on the pathway of the API and the nanocrystals. In order to elucidate the influence of the excipient in more detail, a systematic study was conducted to investigate the influence of excipients on the penetration efficacy of the formulated API and the pathway of nanocrystals upon dermal application. Results showed that already small quantities of excipients can strongly affect the passive dermal penetration of curcumin and the hair follicle targeting of curcumin nanocrystals. The addition of 2% ethanol promoted hair follicle targeting of nanocrystals and hampered passive diffusion into the stratum corneum of the API, whereas the addition of glycerol hampered hair follicle targeting and promoted passive diffusion. Propylene glycol was found to promote both pathways. In fact, the study proved that formulating nanocrystals to improve the bioefficacy of poorly soluble API upon dermal application is highly effective. However, this is only true, if the correct excipient is selected for the formulation of the vehicle. The study also showed that excipients can be used to allow for a targeted dermal drug delivery, which enables to control if API should be delivered via passive diffusion and/or as drug reservoir by depositing API in the hair follicles.

Effect of urea cream on sorafenib-associated hand-foot skin reaction in patients with hepatocellular carcinoma: A multicenter, randomised, double-blind controlled study

BACKGROUND

Hand-foot skin reaction (HFSR) is the most common adverse event during sorafenib treatment in patients with hepatocellular carcinoma (HCC). In the present study, we aimed to investigate the role of urea cream in the prevention of HFSR or amelioration of HFSR severity.

PATIENTS AND METHODS

Patients with HCC were treated with either placebo cream or urea cream for 12 weeks concomitantly with sorafenib treatment. HFSR development, the Hand-Foot Skin Reaction and Quality of Life (HF-QoL) questionnaire score, and adverse events were assessed at 2, 4, 8 and 12 weeks.

RESULTS

Of the 288 patients, 247 patients, with 117 patients in the placebo control group and 130 patients in the urea cream group, were analysed. The urea cream group showed a trend towards a lower cumulative incidence of any-grade HFSR (log-rank, P = 0.247) and severe HFSR of grade II or higher (log-rank, P = 0.394) without statistical significance. In the incidence by time point, the incidence of severe HFSR of grade II or higher was significantly lower in the urea cream group than in the placebo control group at 2 weeks (13.8% versus 23.9%, P = 0.042). The urea cream group showed a significantly better HF-QoL questionnaire score than the placebo control group (11.8 versus 19.7, P = 0.014) at 12 weeks.

CONCLUSIONS

Treatment with urea cream showed a lower incidence of severe sorafenib-induced HFSR at 2 weeks and reduced the tendency of HFSR development in HCC patients. Therefore, treatment with urea cream may be considered for prophylaxis or improvement of HFSR grade in HCC patients treated with sorafenib.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03212625).

GC-MS-Based Metabolomics Analysis of Prawn Shell Waste Co-Fermentation by Lactobacillus plantarum and Bacillus subtilis

GC-MS-based metabolomics were used to investigate metabolic changes in prawn shell waste during fermentation. Microbial strains Lactobacillus plantarum and Bacillus subtilis were co-fermented in a shake flask comprising of 5% (w/v) prawn shell waste and 20% (w/v) glucose as a carbon source. Analysis of the prawn shell waste fermentation showed a total of 376 metabolites detected in the culture supernatant, including 14 amino acids, 106 organic acids, and 90 antimicrobial molecules. Results show that the liquid fraction of the co-fermentation is promising for harvesting valuable metabolites for probiotics application.

Psoriasis and Antimicrobial Peptides

Psoriasis is a systemic inflammatory disease caused by crosstalk between various cells such as T cells, neutrophils, dendritic cells, and keratinocytes. Antimicrobial peptides (AMPs) such as β-defensin, S100, and cathelicidin are secreted from these cells and activate the innate immune system through various mechanisms to induce inflammation, thus participating in the pathogenesis of psoriasis. In particular, these antimicrobial peptides enhance the binding of damage-associated molecular patterns such as self-DNA and self-RNA to their receptors and promote the secretion of interferon from activated plasmacytoid dendritic cells and keratinocytes to promote inflammation in psoriasis. Neutrophil extracellular traps (NETs), complexes of self-DNA and proteins including LL-37 released from neutrophils in psoriatic skin, induce Th17. Activated myeloid dendritic cells secrete a mass of inflammatory cytokines such as IL-12 and IL-23 in psoriasis, which is indispensable for the proliferation and survival of T cells that produce IL-17. AMPs enhance the production of some of Th17 and Th1 cytokines and modulate receptors and cellular signaling in psoriasis. Inflammation induced by DAMPs, including self-DNA and RNA released due to microinjuries or scratches, and the enhanced recognition of DAMPs by AMPs, may be involved in the mechanism underlying the Köbner phenomenon in psoriasis.

Vehicles for atopic dermatitis therapies: more than just a placebo

A topical vehicle is a 'carrier system' for an active pharmaceutical (or cosmetic) substance, referred to hereafter as the drug, but a vehicle may also be used on its own as an emollient to ameliorate dry skin. It is well established that the vehicle plays an important role in determining the bioavailability of a given drug at its ultimate target within the skin. Yet in the treatment of atopic eczema/dermatitis (AD), wherein the structure and function of the skin's outer barrier play a pivotal role in the development and course of the condition, the interaction of the vehicle with this barrier carries a particular importance. It is now clear that the often-considered inert excipients of a vehicle bring about changes within the skin at the molecular level that promote barrier restoration and enhance innate immune defenses with therapeutic value to AD patients. Moreover, the vehicle control in randomized controlled trials (RCTs) increasingly displays significant efficacy. In light of this, we consider the implications of vehicle design in relation to AD pathophysiology and the role vehicles play as controls in RCTs of new drug treatments for this condition.

Diagnosis and treatment of xerosis cutis - a position paper

BACKGROUND AND RATIONALE

Xerosis cutis (also referred to as xeroderma, dry skin, asteatosis) affects more than 10 million individuals in Germany. It is among the most common dermatological diagnoses and a cardinal symptom of many dermatological, internal and neurological diseases. Even though it has been established that basic skin care plays a significant role in the management of patients with xerosis cutis, there are as yet no evidence-based algorithms for diagnosis and treatment.

OBJECTIVE

The present position paper provides physicians across all specialties with a practical, symptom-based approach to the prevention, diagnosis and treatment of xerosis cutis.

METHODS

Within a structured decision-making process, a panel of experienced dermatologists first defined questions relevant to everyday clinical practice, which were then addressed by a systematic review of the literature. Based on the evidence available as well as expert consensus, diagnostic and treatment algorithms were subsequently developed and agreed upon.

RESULTS

Xerosis cutis is generally diagnosed on clinical grounds. Possible trigger factors must be avoided, and comorbidities should be adequately and specifically treated. Suitable skin care products should be chosen with a view to improving skin hydration and restoring its barrier function. They should therefore contain both rehydrating and lipid-replenishing components. The "drier" the skin appears, the greater the lipid content should be (preferably using water-in-oil formulations). The choice of ingredients is based on a patient's individual symptoms, such as scaling (e.g., urea), fissures/rhagades (e.g., urea or dexpanthenol), erythema (e.g., licochalcone A) and pruritus (e.g., polidocanol). Other factors to be considered include the site affected and patient age. Ingredients or rather combinations thereof for which there is good clinical evidence should be preferentially used. The best evidence by far is available for urea, whose efficacy in the treatment of xerosis is further enhanced by combining it with other natural moisturizing components and ceramides. The "xerosimeter" is a tool developed in an effort to facilitate patient management and for training purposes. It not only includes practical tools for diagnosis and follow-up but also a classification of ingredients and a structured treatment algorithm.

CONCLUSION

The structured symptom- and evidence-based approach proposed herein contains a road map for diagnosis and treatment of xerosis cutis. It aims to raise awareness in terms of prevention and early treatment of this condition and may thus improve quality of life and prevent potential sequelae.

Ethanol-Based Disinfectants Containing Urea May Reduce Soap Sensitivity

BACKGROUND

The use of disinfectants is crucial to preventing the spread of nosocomial infections in health care workers. As many as 25 applications of hand disinfectants is a realistic default value during a working day. However, alcohol-based hand disinfectants may weaken skin barrier function and induce dryness and eczema, which decrease their acceptance.

OBJECTIVE

To evaluate the effect of ethanol-containing disinfectants with 5% urea on skin barrier function and on sensitivity to an irritant soap (sodium lauryl sulfate [SLS]).

METHODS

Twenty healthy volunteers treated one of their forearms twice daily for 17 days with an ethanol-containing gel with 5% urea. Two types of gels with urea were tested. Treatment was randomized to left or right forearm, and the contralateral forearm served as untreated control. Transepidermal water loss, skin capacitance (dryness), and sensitivity to SLS were evaluated.

RESULTS

Twice-daily application of the urea-containing ethanol gels lowered transepidermal water loss, prevented dryness, and reduced sensitivity to SLS compared with the untreated control skin.

CONCLUSIONS

Improved barrier function using this ethanol gel with urea may have relevance in daily disinfectant procedures.

Hygiene and emollient interventions for maintaining skin integrity in older people in hospital and residential care settings

BACKGROUND

Ageing has a degenerative effect on the skin, leaving it more vulnerable to damage. Hygiene and emollient interventions may help maintain skin integrity in older people in hospital and residential care settings; however, at present, most care is based on "tried and tested" practice, rather than on evidence.

OBJECTIVES

To assess the effects of hygiene and emollient interventions for maintaining skin integrity in older people in hospital and residential care settings.

SEARCH METHODS

We searched the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL, up to January 2019. We also searched five trials registers.

SELECTION CRITERIA

Randomised controlled trials comparing hygiene and emollient interventions versus placebo, no intervention, or standard practices for older people aged ≥ 60 years in hospital or residential care settings.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane. Primary outcomes were frequency of skin damage, for example, complete loss of integrity (tears or ulceration) or partial loss of integrity (fissuring), and side effects. Secondary outcomes included transepidermal water loss (TEWL), stratum corneum hydration (SCH), erythema, and clinical scores of dryness or itch. We used GRADE to assess the quality of evidence.

MAIN RESULTS

We included six trials involving 1598 residential care home residents; no included trial had a hospital setting. Most participants had a mean age of 80+ years; when specified, more women were recruited than men. Two studies included only people with diagnosed dry skin. Studies were conducted in Asia, Australasia, Europe, and North America. A range of hygiene and emollient interventions were assessed: a moisturising soap bar; combinations of water soak, oil soak, and lotion; regular application of a commercially available moisturiser; use of two different standardised skin care regimens comprising a body wash and leave-on body lotion; bed bath with "wash gloves" containing numerous ingredients; and application of a hot towel after usual care bed bath. In five studies, treatment duration ranged from five days to six months; only one study had post-treatment follow-up (one to eight days from end of treatment). Outcomes in the hot towel study were measured 15 minutes after the skin was wiped with a dry towel. Three studies each had high risk of attrition, detection, and performance bias. Only one trial (n = 984) assessed frequency of skin damage via average monthly incidence of skin tears during six months of treatment. The emollient group (usual care plus twice-daily application of moisturiser) had 5.76 tears per month per 1000 occupied bed-days compared with 10.57 tears in the usual care only group (ad hoc or no standardised skin-moisturising regimen) (P = 0.004), but this is based on very low-quality evidence, so we are uncertain of this result. Only one trial (n = 133) reported measuring side effects. At 56 ± 4 days from baseline, there were three undesirable effects (itch (mild), redness (mild/moderate), and irritation (severe)) in intervention group 1 (regimen consisting of a moisturising body wash and a moisturising leave-on lotion) and one event (mild skin dryness) in intervention group 2 (regimen consisting of body wash and a water-in-oil emulsion containing emollients and 4% urea). In both groups, the body wash was used daily and the emollient twice daily for eight weeks. There were zero adverse events in the usual care group. This result is based on very low-quality evidence. This same study also measured TEWL at 56 ± 4 days in the mid-volar forearm (n = 106) and the lower leg (n = 105). Compared to usual care, there may be no difference in TEWL between intervention groups, but evidence quality is low. One study, which compared application of a hot towel for 10 seconds after a usual care bed bath versus usual care bed bath only, also measured TEWL at 15 minutes after the skin was wiped with a dry towel for one second. The mean TEWL was 8.6 g/m²/h (standard deviation (SD) 3.2) in the hot towel group compared with 8.9 g/m²/h (SD 4.1) in the usual care group (low-quality evidence; n = 42), showing there may be little or no difference between groups. A lower score is more favourable. Three studies (266 participants) measured SCH, but all evidence is of very low quality; we did not combine these studies due to differences in treatments (different skin care regimens for eight weeks; wash gloves for 12 weeks; and single application of hot towel to the skin) and differences in outcome reporting. All three studies showed no clear difference in SCH at follow-up (ranging from 15 minutes after the intervention to 12 weeks from baseline), when compared with usual care. A clinical score of dryness was measured by three studies (including 245 participants); pooling was not appropriate. The treatment groups (different skin care regimens for eight weeks; a moisturising soap bar used for five days; and combinations of water soak, oil soak, and lotion for 12 days) may reduce dryness compared to standard care or no intervention (results measured at 5, 8, and 56 ± 4 days after treatment was initiated). However, the quality of evidence for this outcome is low. Outcomes of erythema and clinical score of itch were not assessed in any included studies.

AUTHORS' CONCLUSIONS

Current evidence about the effects of hygiene and emollients in maintaining skin integrity in older people in residential and hospital settings is inadequate. We cannot draw conclusions regarding frequency of skin damage or side effects due to very low-quality evidence. Low-quality evidence suggests that in residential care settings for older people, certain types of hygiene and emollient interventions (two different standardised skin care regimens; moisturising soap bar; combinations of water soak, oil soak, and lotion) may be more effective in terms of clinical score of dryness when compared with no intervention or standard care. Studies were small and generally lacked methodological rigour, and information on effect sizes and precision was absent. More clinical trials are needed to guide practice; future studies should use a standard approach to measuring treatment effects and should include patient-reported outcomes, such as comfort and acceptability.

Insights into atopic dermatitis gained from genetically defined mouse models

Atopic dermatitis (AD) is characterized by severe pruritus and recurrent eczema with a chronic disease course. Impaired skin barrier function, hyperactivated T_H2 cell-type inflammation, and pruritus-induced scratching contribute to the disease pathogenesis of AD. Skin microbial alterations complicate the pathogenesis of AD further. Mouse models are a powerful tool to analyze such intricate pathophysiology of AD, with a caution that anatomy and immunology of the skin differ between human subjects and mice. Here we review recent understanding of AD etiology obtained using mouse models, which address the epidermal barrier, skin microbiome, T_H2 immune response, and pruritus.

Cellular and Molecular Mechanisms in the Pathogenesis of Classical, Vascular, and Hypermobile Ehlers‒Danlos Syndromes

The Ehlers‒Danlos syndromes (EDS) constitute a heterogenous group of connective tissue disorders characterized by joint hypermobility, skin abnormalities, and vascular fragility. The latest nosology recognizes 13 types caused by pathogenic variants in genes encoding collagens and other molecules involved in collagen processing and extracellular matrix (ECM) biology. Classical (cEDS), vascular (vEDS), and hypermobile (hEDS) EDS are the most frequent types. cEDS and vEDS are caused respectively by defects in collagen V and collagen III, whereas the molecular basis of hEDS is unknown. For these disorders, the molecular pathology remains poorly studied. Herein, we review, expand, and compare our previous transcriptome and protein studies on dermal fibroblasts from cEDS, vEDS, and hEDS patients, offering insights and perspectives in their molecular mechanisms. These cells, though sharing a pathological ECM remodeling, show differences in the underlying pathomechanisms. In cEDS and vEDS fibroblasts, key processes such as collagen biosynthesis/processing, protein folding quality control, endoplasmic reticulum homeostasis, autophagy, and wound healing are perturbed. In hEDS cells, gene expression changes related to cell-matrix interactions, inflammatory/pain responses, and acquisition of an in vitro pro-inflammatory myofibroblast-like phenotype may contribute to the complex pathogenesis of the disorder. Finally, emerging findings from miRNA profiling of hEDS fibroblasts are discussed to add some novel biological aspects about hEDS etiopathogenesis.

Enhanced In Situ Availability of Aphanizomenon Flos-Aquae Constituents Entrapped in Buccal Films for the Treatment of Oxidative Stress-Related Oral Diseases: Biomechanical Characterization and In Vitro/Ex Vivo Evaluation

In recent years, the key role of oxidative stress in pathogenesis of oral diseases has been emphasized and the use of antioxidant agents has been encouraged. Aphanizomenon flos-aquae (AFA) is a unicellular blue-green alga with antioxidant and anti-inflammatory properties. The aim of this study was the formulation and characterization of mucoadhesive thin layer films loaded with AFA, finalized to the treatment of oxidative stress (OS)-related oral diseases. First, to enhance the bioavailability of AFA constituents, the raw food grade material was appropriately treated by a high frequency homogenization able to disrupt cell walls. Thus, Eudragit^® E100-based buccal films were produced by the solvent casting method, containing 7% and 18% of AFA. The films, characterized by uniformity in thickness, weight, and drug content, showed low swelling degree, good muco-adhesiveness and controlled drug release. The mechanical tests showed elastic moduli of films of almost 5 MPa that is well-suitable for human buccal applications without discomfort, besides biaxial tests highlighted a marked material isotropy. Permeation studies through porcine mucosae demonstrated the ability of films to promote AFA penetration in the tissues, and when sublingually administered, they produced a drug flux up to six-fold higher than an AFA solution. The new formulations represent an interesting alternative for the development of cosmetics and nutraceuticals with a functional appeal containing plant extracts.

Pathomechanism of 'skin-originated' allergic diseases

The skin is outermost barrier of the body and protects us from various kinds of external stimuli. The barrier function of the skin is, however, not wholly perfect but include some 'security holes' where external antigen invades in. Further, external antigens themselves have some specific shunt pathways to breach the skin barrier. Recent studies revealed that percutaneous sensitization is a strong inducer of systemic immune responses and it is now considered that majority of food allergy is sensitized through body surfaces. Thus, to know about the fundamental structure of the skin barrier and its potential weak spots must be important for understanding the pathomechanism of 'skin-originated' allergic diseases. In this review, I overview the fundamental features of the skin barrier, and then, will discuss the pathomechanism how external antigens breach the barrier and induce subsequent systemic allergic reactions.

Up-regulated mRNA expression of some anti-inflammatory mediators in bovine oviduct epithelial cells by urea in vitro: Cellular pathways by Reactome analysis

Increased urea concentration is a major cause of low fertility in dairy cows fed high-protein diets. A strong correlation exists between the urea concentration in the blood and oviduct fluid of dairy cows. In this study, bovine oviduct epithelial cells (BOECs) were incubated with varying concentrations of urea (0, 20, 40, and 80 mg/dL) in the absence of ovarian sex steroids (estradiol and progesterone) and luteinizing hormone. The 80 mg/dL urea reduced the cell viability, and thus was excluded in further analysis. Compared to the control (U0), the 20 mg/dL urea (U20) increased the mRNA expression of Toll-like receptor (TLR) 4, interleukin (IL) 10, IL4, and prostaglandin (PG) E synthase (mPGES) but decreased the mRNA expression of tumor necrosis factor α (TNFA). Compared to U0, the 40 mg/dL urea (U40) decreased the mRNA expression of TNFA and increased alpha-1-acid glycoprotein (AGP). U40 also increased TLR2, IL10, and IL4 mRNA expression compared to U0. In addition, compared to U20, the U40 decreased the mRNA expression of TLR4 and IL1B but increased that of AGP and TLR2. Subsequently, the mRNA expression data were then projected into the Reactome database. The Reactome analysis showed that pathways, including cytokine signaling in the immune system (i.e., TNFs bind their physiological receptors) and death receptor signaling (i.e., TNF signaling), were down-regulated in the presence of urea compared to the U0 group. These in vitro data implied that high urea level can alter the balance between pro- and anti-inflammatory responses in BOECs, thus providing a suboptimal environment for the early reproductive events or a weakened innate immune system, predisposing the oviduct to infections.

Topical urea in skincare: A review

Alterations in barrier function are associated with a number of skin diseases, including xerosis, atopic dermatitis, and psoriasis. Urea, a component of the natural moisturizing factor of the skin, plays an important role in the preservation of skin hydration and integrity. Several studies have investigated the effects of urea in the clinical setting. Here, we summarize the available clinical evidence regarding the effects of urea in the maintenance of healthy skin and management of skin disorders. At lower doses (≤10%), urea-containing topical formulations act as a skin moisturizer, while at higher concentrations (>10% urea), urea-based preparations exert a keratolytic action. Urea is also useful in combination therapies with anti-inflammatory and anti-fungal drugs, due to its activity as a penetration enhancer.