Disturbed Epidermal Barrier Research Articles

A review of biological agents and small molecules in the management of atopic dermatitis

Atopic dermatitis (AD) is a recurrent, chronic, and non-infectious inflammatory dermatoses characterized by persistent itching of the skin. It has multifactorial causes characterized by a tetrad of a (i) genetic predisposition, (ii) disturbed epidermal barrier, (iii) immune dysregulation, and (iv) deranged skin microbiome. At present, treatment is aimed at maintaining the epidermal barrier function by the use of emollients, sedative, and non-sedative antihistamines targeting the itch pathway, immunosuppressants in the form of steroids as well as steroid sparing agents to control the chronic persistent inflammatory response. However, newer emerging therapy in the form of biologics gives a promising approach to control the chronic, persistent inflammatory response by targeting the specific cytokines involved in pathogenesis of AD.

Epidermal barrier function in patients after allogeneic hematopoietic stem cell transplantation - a pilot study.

The skin is the typically and predominantly affected organ in patients after allogeneic hematopoietic stem cell transplantation (alloHSCT). The supportive therapy in patients after alloHSCT includes especially ultraviolet protection and the use of emollients. Due to the lack of studies regarding epidermal barrier function in patients with alloHSCT, our aims were to monitor dermatologically patients 1 year after the procedure with special emphasis on epidermal barrier function and to evaluate the properties of epidermal barrier function in patients with confirmed chronic GvHD (cGvHD). Our pilot study included 30 patients after alloHSCT and 20 healthy controls. In the group of patients after alloHSCT there were 10 individuals who were monitored dermatologically (including evaluation of skin, mucosae, nails and hair) within 1 year after the procedure (subgroup 1) and 20 patients with previously confirmed cGvHD (subgroup 2). We evaluated transepidermal water loss (TEWL), skin hydration and skin color. The clinical assessment and all noninvasive evaluations in patients included in subgroup 1 were performed before (at baseline) and 3, 6, 9 and 12 months after the procedure, while in subgroup 2 they were performed once. In subgroup 1 we did not observe significant differences between baseline results and periods of assessments in TEWL values or corneometry, erythema and melanin measurements. In subgroup 2 the highest TEWL values and the lowest corneometry results were observed in patients with sclerodermoid chronic cutaneous GvHD in comparison to patients with lichenoid chronic cutaneous GvHD and patients with cGvHD but without skin lesions. TEWL values and melanin level were significantly higher in patients with cGvHD than in controls. Our pioneer observations proved the disturbed epidermal barrier function among patients after alloHSCT. Therefore it seems that proper skin care, including photoprotection, should be recognized as a crucial component in long-term management of these patients.

Analysis of Results of Specific IgE in 100 Atopic Dermatitis Patients with the Use of Multiplex Examination ALEX2-Allergy Explorer.

Background and aim: Progress in laboratory diagnostics of IgE-mediated allergy is the use of component-resolved diagnosis. Our study analyses the results of specific IgE to 295 allergen reagents (117 allergenic extracts and 178 molecular components) in patients suffering from atopic dermatitis (AD) with the use of ALEX2 Allergy Explorer. Method: The complete dermatological and allergological examination, including the examination of the sensitization to molecular components with ALEX2 Allergy Explorer testing, was performed. The statistical analysis of results was performed with these methods: TURF (total unduplicated reach and frequency), best reach and frequency by group size, two-sided tests, Fisher’s exact test, and chi-square test (at an expected minimum frequency of at least 5). Results: Altogether, 100 atopic dermatitis patients were examined: 48 men, 52 women, the average age 40.9 years, min. age 14 years, max. age 67 years. The high and very high level of specific IgE was reached in 75.0% of patients to 18 molecular components: from PR-10 proteins (Aln g 1, Bet v 1, Cor a1.0103, Cor a1.0401, Fag s 1), lipocalin (Can f 1), NPC2 family (Der f 2, Der p 2), uteroglobin (Fel d 1), from Alternaria alternata (Alt a 1), Beta expansin (Lol p 1, Phl p 1), molecular components from Timothy, cultivated rye (Secc pollen) and peritrophin-like protein domain Der p 23. The high and very high level of specific IgE to other lipocalins (Fel d 7, Can f 4), to arginine kinase (Bla g 9, German cockroach), and to allergen extracts Art v (mugwort), and Cyn d (Bermuda grass) reached 52.0% of patients. The severity of AD is in significant relation to the sensitization to molecular components of storage mites (Gly d 2, Lep d 2—NPC2 family), lipocalins (Can f 1, Can f 2, Can f 4, and Can f 6), arginine kinase (Asp f 6, Bla g 9, Der p 20, Pen m 2), uteroglobin (Fel d 1, Ory c 3), Mn superoxide dismutase (Mala s 11), PR-10 proteins (Fag s 1, Mal d 1, Cor a 1.0401, Cor a 1.0103), molecular components of the peritrophin-like domain (Der p 21, Der p 23), and to Secc pollen. In the subgroup of patients suffering from bronchial asthma, the significant role play molecular components from house dust mites and storage mites (Lep d 2, Der p 2, Der f 2—NPC2 family), cysteine protease (Der p 1), peritrophin-like protein domain (Der p 21, Der p 23), enolase from Alternaria alternata (Alt a 6), and Beta expansin Phl p 1. Conclusion: The results of our study demonstrate the detailed profile of sensitization to allergens reagents (allergen extract and molecular components) in patients with atopic dermatitis. We show the significance of disturbed epidermal barrier, resulting in increased penetration of allergens. We confirmed the significant relationship between the severity of AD, the occurrence of bronchial asthma and allergic rhinitis, and high levels of specific IgE to allergen reagents. Our results may be important for regime measures and immunotherapy; Der p 23 shall be considered as an essential component for the diagnosis and specific immunotherapy of house dust mite allergy.

The knowledge of skin care rules in patients with acne vulgaris

Acne vulgaris is one of the most common dermatological disease which may present with disturbed epidermal barrier function, exacerbated by drugs used to treat acne, both general and local. The instructing patients with acne in the selection of appropriate cosmetic products, significantly improves their quality of life. The aim of the study was to gain the knowledge of acne patients about the skin care principles. The study involved 80 patients suffering from acne vulgaris and showed the need to conduct education in the field of proper care of the acne skin.

Birch pollen influence the severity of atopic eczema - prospective clinical cohort pilot study and ex vivo penetration study.

There is little clinical evidence for a correlation between the severity of atopic eczema (AE) and pollen exposition. To obtain more data, we performed a clinical cohort pilot study about the influence of pollen on AE between sensitized and nonsensitized subjects and an experimental study addressing the cutaneous penetration of pollen into the skin. Fifty-five patients were monitored during birch pollen season. To study the cutaneous penetration, grass pollen allergens were applied on excised skin and the uptake in CD1c-expressing dendritic cells was investigated. The correlation between environmental pollen load and severity of the Scoring Atopic Dermatitis (SCORAD) score and pruritus was observed, regardless of the status of sensitization. The sensitized group recovered significantly worse after the birch pollen season. Remarkably higher amounts of pollen allergens taken up by CD1c cells were detected in epidermal cells derived from skin explants with a disturbed epidermal barrier. These findings suggest an exacerbating role of pollen in AE utilizing the epidermal route.

Analysis of Filaggrin Mutations and Expression in Corneal Specimens from Patients with or without Atopic Dermatitis

Background: Filaggrin is expressed in the epidermis and is essential for the maintenance of the epidermal barrier. Null mutations within the filaggrin gene (FLG) lead to a disturbed epidermal barrier and are associated with a significantly increased risk of atopic dermatitis (AD). The association of AD with ocular surface disorders prompted us to speculate that common FLG mutations may be particularly prevalent in AD patients with ocular comorbidities. Methods: Corneal buttons and biopsies from AD patients with ocular involvement (n = 11) and from non-atopic patients (n = 9) with a histological diagnosis of keratitis were included in the study. DNA samples obtained from paraffin-embedded corneal specimens were genotyped for the two most common FLG mutations (R501X and 2282del4). Filaggrin protein expression was analysed by immunohistochemistry. Results: Normal skin and corneal specimens (n = 6) were positive for filaggrin, which could be detected in the stratum corneum of the skin and in the basal epithelial layer of the cornea. Interestingly, all AD corneal specimens as well as the specimens from keratitis patients without AD were negative for filaggrin expression. Genotyping of the FLG mutations R501X and 2282del4 revealed wild-type alleles in all analysed samples. Conclusions: The lack of filaggrin expression observed in the analysed corneal specimens from AD patients is not due to the two most common FLG mutations (R501X, 2282del4) but is most likely secondary to inflammation, as all keratitis specimens of non-AD patients showed lack of filaggrin expression as well.

Defects of filaggrin-like proteins in both lesional and nonlesional atopic skin

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by a disturbed epidermal barrier. In a subset of patients, this is explained by nonsense mutations in the gene encoding filaggrin (FLG). We sought to evaluate the respective role of FLG mutations and proinflammatory cytokines and to assess the expression of FLG, hornerin (HRNR), and FLG2, 2 FLG-like proteins, which are involved in epidermal barrier functions, in normal skin and both lesional and nonlesional skin of patients with AD. An FLG-genotyped cohort of 73 adults with AD and 73 aged-matched control subjects was analyzed by using immunohistochemistry and immunoblotting. Normal primary human keratinocytes were differentiated in either the absence or presence of IL-4, IL-13, and IL-25. Compared with control subjects, FLG, HRNR, and FLG2 were detected at significantly lower levels in the skin of patients with AD, irrespective of their FLG genotype. The reduction was greater in lesional compared with nonlesional skin. In addition, the proFLG/FLG ratio was found to be higher in the skin of wild-type patients than in control subjects. Cytokine treatment of keratinocytes induced a dramatic reduction in FLG, FLG2, and HRNR expression both at the mRNA and protein levels. The stratum corneum of lesional but also clinically unaffected skin of adults with AD is abnormal, with reduced expression of FLG and FLG-like proteins. In addition to nonsense mutations, proinflammatory cytokines and some defects in the proFLG processing can contribute to the FLG downregulation. Our study suggests that skin inflammation reduces the expression of FLG-like proteins, contributing to the AD-related epidermal barrier dysfunction.

The Clinical Impact of Vitamin D in Children With Atopic Dermatitis

The Clinical Impact of Vitamin D in Children With Atopic Dermatitis

Susceptibility of Staphylococcus aureus bacteremia strains to different skin-derived antimicrobial proteins

Staphylococcus aureus is a major human pathogen causing cutaneous infections to life-threatening bacteremia. These infections are often caused by strains derived from the own microflora suggesting that a disturbed epidermal barrier may promote invasion of S. aureus. Antimicrobial peptides and proteins (AMP) such as human beta-defensin-3 and RNase 7 contribute to control the colonization of S. aureus on the skin surface. This leads to the hypothesis that strains with a decreased susceptibility toward skin-derived AMP may better overcome the innate cutaneous defence barrier increasing the possibility of invading into the blood stream. To address this hypothesis we determined whether S. aureus strains from bacteremia patients are less susceptible to various skin-derived AMP than strains from healthy carriers. No differences in the AMP-killing activity against bacteremia-derived S. aureus and control strains were detected suggesting that the onset of S. aureus bacteremia is not based on the varying susceptibilities against skin-derived AMP.

Loss-of-Function Variants of the Filaggrin Gene Are Not Major Susceptibility Factors for Psoriasis Vulgaris or Psoriatic Arthritis in German Patients

Psoriasis vulgaris and atopic dermatitis share a number of features such as chronic cutaneous inflammation and disturbed epidermal barrier function. Genome-wide scans have revealed a conspicuous overlap of susceptibility loci for both diseases involving chromosomal regions 1q21, 3q21, 17q25, and 20p12. Recently, two loss-of-function variants in the gene encoding filaggrin at 1q21 were shown to be strongly associated with atopic dermatitis. In view of a possible genetic overlap of the two skin diseases, we investigated 375 patients suffering from psoriasis vulgaris, 375 patients with psoriatic arthritis, and 376 control probands. Moreover we directly studied expression of filaggrin in 10 patients suffering from psoriasis vulgaris. Our immunohistochemical analysis revealed a checkered pattern with alternating positive broadened or almost absent filaggrin expression. However, no association was found for the two variants of filaggrin (FLG). We conclude that despite a markedly altered filaggrin expression in psoriatic skin, loss-of-function variants of the FLG gene are neither associated with psoriasis vulgaris nor with psoriatic arthritis. The abnormal staining might reflect the altered epidermal differentiation. Our findings imply that the genetic background underlying the epidermal barrier defect in psoriasis is distinct from that found in atopic dermatitis.

Disturbed Epidermal Structure in Mice with Temporally Controlled Fatp4 Deficiency

So far, little is known about the physiological role of fatty acid transport protein 4 (Fatp4, Slc27a4). Mice with a targeted disruption of the Fatp4 gene display features of a human neonatally lethal restrictive dermopathy with a hyperproliferative hyperkeratosis, a disturbed epidermal barrier, a flat dermal-epidermal junction, a reduced number of pilo-sebaceous structures, and a compact dermis, demonstrating that Fatp4 is necessary for the formation of the epidermal barrier. Because Fatp4 is widely expressed, it is unclear whether intrinsic Fatp4 deficiency in the epidermis alone can cause changes in the epidermal structure or whether the abnormalities observed are secondary to the loss of Fatp4 in other organs. To evaluate the functional role of Fatp4 in the skin, we generated a mouse line with Fatp4 deficiency inducible in the epidermis. Mice with epidermal keratinocyte-specific Fatp4 deficiency developed a hyperproliferative hyperkeratosis with a disturbed epidermal barrier. These changes resemble the histological abnormalities in the epidermis of newborn mice with total Fatp4 deficiency. We conclude that Fatp4 in epidermal keratinocytes is essential for the maintenance of a normal epidermal structure.

Mice with targeted disruption of the fatty acid transport protein 4 (Fatp 4, Slc27a4) gene show features of lethal restrictive dermopathy.

The fatty acid transport protein family is a group of evolutionarily conserved proteins that are involved in the cellular uptake and metabolism of long and very long chain fatty acids. However, little is known about their respective physiological roles. To analyze the functional significance of fatty acid transport protein 4 (Fatp4, Slc27a4), we generated mice with a targeted disruption of the Fatp4 gene. Fatp4-null mice displayed features of a neonatally lethal restrictive dermopathy. Their skin was characterized by hyperproliferative hyperkeratosis with a disturbed epidermal barrier, a flat dermal–epidermal junction, a reduced number of pilo-sebaceous structures, and a compact dermis. The rigid skin consistency resulted in an altered body shape with facial dysmorphia, generalized joint flexion contractures, and impaired movement including suckling and breathing deficiencies. Lipid analysis demonstrated a disturbed fatty acid composition of epidermal ceramides, in particular a decrease in the C26:0 and C26:0-OH fatty acid substitutes. These findings reveal a previously unknown, essential function of Fatp4 in the formation of the epidermal barrier.

In vitro and in vivo assessment of the irritation potential of different spin traps in human skin

No clinical data are available on the acute cutaneous toxicity of spin traps which are frequently used in combination with the electron paramagnetic resonance (EPR) technique for detection of free radicals and reactive oxygen/nitrogen species. The purpose of this study was to evaluate the acute dermatotoxicity of the following spin traps in human skin: C-phenyl- N-tert.-butyl nitrone (PBN), C-(4-pyridinyl- N-oxide)- N-tert.-butylnitrone (POBN), 5,5-dimethyl-l-pyrroline- N-oxide(DMPO), 5 diethoxyphosphoryl-5-methyl-l-pyrroline- N-oxide (DEPMPO), diethyldithiocarbamate (DDC) and N-methyl- d-glucamine dithiocarbamate (MGD). The corrosivity of the test substances was first assessed in human skin in vitro by measurement of transcutaneous electrical resistance (TER). In this assay all spin traps were non-corrosive at 500 mM concentration. Subsequently cutaneous irritation of the spin traps was determined at different concentrations (50, 250 and 500 mM) in human skin according to a routine four h human patch test in comparison to the standardized irritant sodium laurylsulfate (SLS, 20%). The response was evaluated clinically as well as by a biophysical method analyzing transepidermal water loss (TEWL). PBN and DEPMPO caused a transient and weak inflammatory reaction at 500 mM in four of 17 and in two of 17 volunteers, respectively. DMPO, POBN, DDC, MGID, and the iron complexes of DDC and MGD were clinically non-irritant at all concentrations tested and no delayed-acute inflammatory reactions were observed. However, the TEWL values were significantly increased by all spin traps except DMPO at 500 mM, indicating disturbed epidermal barrier function. We conclude that the spin traps investigated have a low potential to cause acute skin toxicity and may be used safely for in vivo EPR studies in human skin.