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A defective skin barrier occurs in dogs with atopic dermatitis, and there is controversy over whether this defect pre-exists, or is secondary to allergic inflammation.To study if an allergen challenge decreases the natural moisturising factor (NMF), which contains the main filaggrin degradation products.Four house dust mite (HDM)-sensitised adult atopic dogs from a research colony.Dogs were challenged epicutaneously with HDMs on the right lateral abdomen while the left thorax served as control. We swabbed the skin surface before, and at days (D)1, D2, D3, D7 and D28 after challenge, on both selected sites; swabs were soaked in detergent and frozen until assayed. The NMF components were measured by liquid chromatography-tandem mass spectrometry (LC/MS-MS).The allergen challenge induced moderate skin lesions at the application sites, and also mild erythema at the control areas. The allergen provocation led to significant decreases in the total NMF and its components trans-urocanic acid (t-UCA), pyrrolidone carboxylic acid (PCA) and serine on both sites. Lesion scores abated by D7 and the NMF concentrations had re-increased by D28. Skin lesion scores correlated negatively with the total NMF, t-UCA and PCA concentrations.In this experimental model, a single epicutaneous allergen challenge led to a transient and reversible decrease in skin surface NMF and its components, and concentrations were negatively correlated with skin lesion scores. These observations suggest that some of the skin barrier anomalies seen in atopic dogs likely develop secondarily to the underlying cutaneous allergic inflammation.Un défaut de barrière cutanée existe chez le chien atopique et il y a controverse si ce défaut préexiste ou s’il est secondaire à une inflammation allergique.Etudier si une provocation allergénique diminue le NMF (natural moisturising factor) qui contient les principaux produits de dégradation de la filaggrine.Quatre chiens atopiques sensibilisés aux acariens de poussière de maison (HDM) d’une colonie de recherche. MÉTHODES: Les chiens ont été provoqués par test épicutanés avec HDMs sur l’abdomen latéral droit pendant que le thorax gauche servait de contrôle. Nous avons prélevés la surface de la peau avant et après provocation à D1, D2, D3, D7 et D28 sur les deux faces sélectionnées; les écouvillons ont été trempés dans un détergent et congelés jusqu’aux tests. Les composés NMF ont été mesurés par LC/MS-MS (liquid chromatography-tandem mass spectrometry). RÉSULTATS: La provocation allergénique a induit des lésions modérées aux sites d’application, et aussi un érythème modéré aux zones contrôles. Le test de provocation à mené à des diminutions significatives du NMF total et ses composés t-UCA (trans-urocanic acid), PCA (pyrrolidone carboxylic acid) et sérine sur les deux sites. Les scores lésionnels se calmaient à D7 et les concentrations de NMF ré-augmentaient à D28. Les scores de lésions cutanées corrélaient négativement avec les concentrations de NMF total, t-UCA et PCA.Dans ce modèle expérimental, un test allergénique epicutané unique mène à une diminution réversible et transitoire de NMF de la surface cutanée et de ses composés et les concentrations sont négativement corrélées avec les scores de lésion cutanée. Ces observations suggèrent que certaines des anomalies de barrière cutanée observées chez les chiens atopiques pourraient se développer secondairement à l’inflammation cutanée allergique sous jacente.INTRODUCCIÓN: en perros con dermatitis atópica se observa una barrera cutánea defectuosa, y existe controversia sobre si este defecto existe antes o es secundario a la inflamación alérgica. OBJETIVOS: Estudiar si una exposición con alérgenos disminuye el factor de hidratación natural (NMF), que contiene los principales productos de degradación de la filagrina. ANIMALES: cuatro perros adultos atópicos sensibilizados contra los ácaros del polvo doméstico (HDM) de una colonia de investigación. MÉTODOS: los perros fueron expuestos epicutáneamente con HDM en el abdomen lateral derecho mientras que el tórax izquierdo sirvió como control. Limpiamos la superficie de la piel antes y en los días (D) 1, D2, D3, D7 y D28 después de la exposición, en ambos sitios seleccionados; los hisopos se empaparon en detergente y se congelaron hasta su análisis. Los componentes de NMF se midieron mediante cromatografía líquida-espectrometría de masas en tándem (LC/MS-MS). RESULTADOS: la exposición al alérgeno indujo lesiones cutáneas moderadas en los lugares de aplicación y también eritema leve en las áreas de control. La provocación del alérgeno condujo a disminuciones significativas en el NMF total y en sus componentes ácido transurocánico (t-UCA), ácido pirrolidona carboxílico (PCA) y serina en ambos sitios. Las puntuaciones de las lesiones disminuyeron al D7 y las concentraciones de NMF habían vuelto a aumentar en el D28. Las puntuaciones de las lesiones cutáneas se correlacionaron negativamente con las concentraciones totales de NMF, t-UCA y PCA. CONCLUSIONES E IMPORTANCIA CLÍNICA: en este modelo experimental, una sola exposición a alérgeno epicutáneo condujo a una disminución transitoria y reversible en el NMF de la superficie de la piel y sus componentes, y las concentraciones se correlacionaron negativamente con las puntuaciones de las lesiones cutáneas. Estas observaciones sugieren que algunas de las anomalías de la barrera cutánea observadas en perros atópicos probablemente se desarrollen de forma secundaria a la inflamación alérgica cutánea subyacente.Bei Hunden mit atopischer Dermatitis besteht eine defekte Hautbarriere und es besteht eine Kontroverse darüber, ob dieser Defekt wirklich vor-existiert oder ob er sekundär durch die allergische Entzündung verursacht wird.Es sollte untersucht werden, ob eine Provokation mit dem Allergen den natürlichen Feuchthalte-Faktor (NMF), der die hauptsächlichen Abbauprodukte von Filaggrin enthält, reduziert.Vier erwachsene atopische Hunde aus einer Forschungskolonie, die mit Hausstaubmilben (HDM) sensibilisiert worden waren.Die Hunde wurden epikutan mit den HDMs rechts lateral am Abdomen provoziert, während der linke Thorax als Kontrolle diente. Wir entnahmen vorher und an den Tagen (D) 1, D2, D3, D7 und D28 nach der Provokation von beiden ausgewählten Seiten Tupferproben; die Tupfer wurden in Detergens getränkt und bis zur Untersuchung eingefroren. Die NMF Komponenten wurden mittels Hochleistungsflüssigkeitschromatografie Tandem Massenspektrometrie (LC/MS-MS) gemessen.Die Allergen Provokation induzierte moderate Hautveränderungen an den Applikationsstellen, sowie ein mildes Erythem an den Kontrollstellen. Die Allergen Provokation führte auf beiden Seiten zu signifikanten Abnahmen der totalen NMF und seiner Komponenten Trans-Urocaninsäure (t-UCA), Pyrrolidoncarbonsäure (PCA) und Serin. Die Läsionswerte nahmen mit D7 ab und die NMF Konzentrationen hatten mit D28 wieder zugenommen. Die Werte der Hautläsionen korrelierten negativ mit den Gesamt NMF, t-UCA und PVA Konzentrationen.In diesem experimentellen Modell führt eine einzige epikutane Allergenprovokation zu einer vorübergehenden und reversiblen Zunahme der NMF der Hautoberfläche und seiner Komponenten, die Konzentrationen waren mit den Hautwerten negativ korreliert. Diese Beobachtungen weisen darauf hin, dass einige der Anomalien der Hautbarriere, die bei atopischen Hunden gesehen werden, sich sekundär aufgrund der zugrundeliegenden allergischen Hautentzündung entwickeln.背景: アトピー性皮膚炎の犬では皮膚バリアの欠損が見られるが、この欠損が以前から存在していたのか、あるいはアレルギー性炎症に二次的に生じたものなのかについては議論が分かれている。 目的: 本研究の目的は、アレルゲン負荷が、主なフィラグリン分解産物を含む天然保湿因子 (NMF) を減少させるかどうかを研究することであった。 被験動物: 研究用コロニーのハウスダストマイト (HDM) 感作アトピー成犬4頭。 方法: 犬の右側腹部にHDMを付着させ、左胸部はコントロールとした。負荷前、負荷後1日目、2日目、3日目、7日目、28日目に、選択した両部位の皮膚表面を綿棒で採取し、綿棒は洗剤に浸して測定するまで凍結させた。NMFの成分は、液体クロマトグラフィー・タンデム質量解析法 (LC/MS-MS) で測定した。 結果: アレルゲン負荷は、塗布部位に中程度の皮膚病を誘発し、コントロール部位にも軽度の紅斑が見られた。アレルゲンの誘発により、両部位のNMFおよびその成分であるtrans-urocanic acid (t-UCA)、pyrrolidone carboxylic acid (PCA)、serineが有意に減少した。皮膚病変のスコアはD7までに減少し、NMFの濃度はD28までに再び上昇した。皮膚病変のスコアは、NMF、t-UCAおよびPCAの合計濃度と負の相関があった。 結論と臨床上の重要性: この実験モデルでは、アレルゲンの単回外皮投与により、皮膚表面のNMFとその成分が一過性かつ可逆的に減少し、その濃度は皮膚病変のスコアと負の相関を示した。これらの観察結果は、アトピー犬に見られる皮膚バリアの異常のいくつかは、根底にある皮膚のアレルギー性炎症に続いて発症する可能性が高いことを示唆している。.背景: 特应性皮炎犬的皮肤屏障存在缺陷, 对于该缺陷是预先存在还是继发于过敏性炎症存在争议。 目的: 研究过敏原激发是否会降低含有主要丝聚蛋白降解产物的天然保湿因子(NMF)。 动物: 来自一个研究种群的4只屋尘螨(HDM)致敏的成年特应性犬。 方法: 在犬右侧腹部用HDM进行皮外激发, 同时左胸作为对照。我们在激发前和激发后第(D)1、D2、D3、D7和D28天, 在两个选定部位擦拭皮肤表面; 将拭子浸泡在洗涤剂中并冷冻直至测定。通过液相色谱-串联质谱法(LC/MS-MS)测定NMF组分。 结果: 过敏原激发在用药部位引起中度皮肤病变, 在对照区域也引起轻度红斑。过敏原激发导致两个位点的总NMF及其组分反式尿烷酸(t-UCA)、吡咯烷酮羧酸(PCA)和丝氨酸显著降低。病变评分在D7时减轻, NMF浓度在D28时重新增加。皮肤病变评分与总NMF、t-UCA和PCA浓度呈负相关。 结论和临床重要性: 在该实验模型中, 单次表皮过敏原激发导致皮肤表面NMF及其组分一过性和可逆性降低, 且浓度与皮肤病变评分呈负相关。这些观察结果表明, 在特应性犬中观察到的一些皮肤屏障异常可能继发于潜在的皮肤过敏炎症。.Defeitos de barreira cutânea ocorrem em cães com dermatite atópica, e há controvérsias se esse defeito é pré-existente, ou secundário à inflamação alérgica.Estudar se um desafio alergênico é capaz reduzir o fator hidratante natural (NMF), que contém os principais produtos de degradação de filagrina.Quatro cães atópicos adultos sensibilizados por ácaros da poeira doméstica (HDM) de uma colônia de pesquisa. MÉTODOS: Os cães foram desafiados por via epicutânea com HDMs no abdômen lateral direito, enquanto o tórax esquerdo serviu como controle. Friccionamos a superfície da pele com swabs antes, e nos dias (D) 1, D2, D3, D7 e D28 após o desafio, em ambos os locais selecionados; os swabs permaneceram embebidos em detergente e congelados até serem processados. Os componentes NMF foram medidos por espectrometria de massa de cromatografia líquida-tandem (LC/MS-MS).O desafio alergênico induziu lesões de pele moderada nos locais de aplicação, e também eritema discreto nas áreas de controle. O desafio alergênico levou a diminuições significativas no NMF total e em seus componentes ácido trans-urocânico (t-UCA), ácido carboxílico pirrolidona (PCA) e serina em ambos os locais. Os escores de lesão diminuíram no D7 e as concentrações de NMF aumentaram novamente no D28. Os escores de lesão de pele correlacionaram negativamente com as concentrações de NMF total, t-UCA e PCA. CONCLUSÕES E IMPORTÂNCIA CLÍNICA: Neste modelo experimental, um único desafio de alergênico epicutâneo levou a uma redução transitória e reversível NMF superficial e seus componentes, e as concentrações foram negativamente correlacionadas com as pontuações da lesão da pele. Essas observações sugerem que algumas das anomalias de barreira da pele observadas em cães atópicos provavelmente se desenvolvem secundariamente à inflamação alérgica cutânea subjacente.

Summary: Chronic allergic itch is a common symptom affecting millions of people and animals, but its pathogenesis is not fully explained. Herein, we show that periostin, abundantly expressed in the skin of patients with atopic dermatitis (AD), induces itch in mice, dogs, and monkeys. We identify the integrin αVβ3 expressed on a subset of sensory neurons as the periostin receptor. Using pharmacological and genetic approaches, we inhibited the function of neuronal integrin αVβ3, which significantly reduces periostin-induced itch in mice. Furthermore, we show that the cytokine TSLP, the application of AD-causing MC903 (calcipotriol), and house dust mites all induce periostin secretion. Finally, we establish that the JAK/STAT pathway is a key regulator of periostin secretion in keratinocytes. Altogether, our results identify a TSLP-periostin reciprocal activation loop that links the skin to the spinal cord via peripheral sensory neurons, and we characterize the non-canonical functional role of an integrin in itch. : Mishra et al. demonstrate periostin-induced itch in mice, dogs, and monkeys and identify the integrin αVβ3 as the periostin neuronal receptor. They find that keratinocytes release periostin in response to TSLP, thus identifying a possible reciprocal vicious circle implicating the cytokine TSLP and periostin in chronic allergic itch. Keywords: atopic dermatitis, AD, chronic allergic itch, integrin, JAK/STAT, keratinocytes, NPPB, periostin, sensory neuron, TRPV1, TRPA1, TSLP

Chronic allergic itch is a major symptom that affects millions of people and animals, but its pathogenesis is not fully explained. Here, we show that one of the mediators abundantly present in the skin of patients with atopic dermatitis, periostin, induces itch via sensory neurons in mice, dogs, and monkeys. We identified the periostin receptor, the integrin αvβ3 expressed on a subset of sensory neurons. Using pharmacological and genetic approaches, we inhibited the function of this neuronal integrin αvβ3, which significantly reduced periostin-mediated itch in mice. Furthermore, we showed that the cytokine TSLP, and the application of the AD-causing MC903 (calcipotriol) and house dust mites induced periostin secretion. Finally, we established that the JAK/STAT pathway is a key regulator of periostin secretion in keratinocytes. Overall, our results identified a TSLP-periostin reciprocal activation that links the skin to the central nervous system via peripheral sensory neurons, and we characterized the non-canonical functional role of a neuronal integrin in itch behavior.

Background As prednisone and ciclosporin can have immunosuppressive effects and have been considered potential predisposing factors for skin infections, we investigated the impact of these drugs on the diversity of the cutaneous microbiota, the abundance of Malassezia and infection with Papillomaviruses. Results Six atopic, asymptomatic Maltese-beagle dogs were treated with ciclosporin for one month and then with prednisone for another month, with a one-month wash-out between treatments. The dogs were sampled on the abdomen and pinna before and after each treatment using a swab. Samples for Papillomavirus detection were obtained with cytobrush sticks. The bacterial microbiota was characterized using 16S amplicon high-throughput sequencing. Malassezia populations were quantified with nested real-time PCR targeting the ribosomal internal transcribed spacer 1. The diversity and composition of cutaneous microbiota was not impacted in a detectable manner by any of the treatments. As observed for the bacterial microbiota, Malassezia populations were not affected by treatment. Three dogs were positive for Papillomavirus at more than one timepoint, but an association with treatment was not apparent. Conclusions Ciclosporin and prednisone at doses used for the treatment of atopic dermatitis do not impact the canine cutaneous microbiota in a detectable manner. Electronic supplementary material The online version of this article (10.1186/s12917-018-1370-y) contains supplementary material, which is available to authorized users.

Background Diluted sodium hypochlorite represents an inexpensive and widely available topical antiseptic, but there are no tolerability and efficacy data in veterinary dermatology. Objectives To determine the in vivo antibacterial effect and tolerability of topical diluted bleach application and to assess its in vitro effect on skin barrier lipids and anti-inflammatory properties on keratinocytes. Methods Topical hypochlorite at 0.05% and tap water were applied to both sides of the thorax of four healthy dogs. The anti-inflammatory effect on canine keratinocytes was determined by real-time polymerase chain reaction; skin barrier integrity was assessed by evaluating stratum corneum lipid changes in canine stratified epidermal constructs. Results The cell viability of primary keratinocytes treated with water and diluted hypochlorite at 0.005 and 0.01%, reduced the percentage of viable cells by 10%. The exposure of primary keratinocytes to 0.005% diluted hypochlorite significantly reduced the induction of inflammatory genes chemokine ligand-2 (CCL2; P = 0.015) and thymus and activation-regulated chemokine (TARC/CCL17, P = 0.032). There were no changes in skin lipid ceramide and nonceramide fractions in stratified epidermal constructs cultured for 17 days with 0.05% hypochlorite. Topical hypochlorite at 0.05% and tap water were well-tolerated without signs of skin irritation. Although a marked reduction in bacterial counts was seen within 20 min of diluted bleach application compared to the tap water control, this was only marginally significant (P = 0.06). Conclusions and clinical importance The results indicate that a topical diluted bleach solution, at either 0.05 or 0.005% hypochlorite concentrations, is a well-tolerated antiseptic that also exhibits anti-inflammatory properties.

Background Allergen immunotherapy is currently the only intervention proposed to specifically prevent clinical flares after allergen challenges. The low molecular weight Der f 2 (Df2) is a major allergen in Japanese dogs sensitized to Dermatophagoides farinae house dust mites. Objectives Pilot, blinded, placebo-controlled experiment testing the efficacy of subcutaneous immunotherapy (SCIT) with high doses of recombinant Df2 conjugated to the maltotriose pullulan (rDf2-P). Methods Eight Maltese beagle atopic dogs were sensitized to rDf2 then randomized to SCIT with rDf2-P (six dogs) or placebo (two). The immunotherapy consisted of six weekly injections of increasing doses (0.1–10.0 μg) of rDf2-P followed by four monthly injections of 10 μg of this allergen. Epicutaneous rDf2 challenges, rDf2-specific IgE serology and intradermal reactivity, as well as serum cytokine level measurements, were performed throughout the study. Results Subcutaneous injections of placebo did not alter the cutaneous reactivity after rDf2 challenge, while that of the dogs treated with rDf2-P SCIT disappeared in five of six dogs (83%) and was reduced in one of six (17%). During SCIT maintenance, skin lesion scores were significantly lower in dogs receiving SCIT compared to those treated with placebo. This clinical improvement was accompanied by a concurrent, yet not significant, decrease in rDf2-specific IgE serology and immediate intradermal reactivity. Cytokine serum levels were inconclusive. There were no adverse events seen with rDf2-P SCIT. Conclusions and clinical importance The new mono-allergen SCIT appears safe and effective for reducing skin lesions after allergen challenges; it deserves further testing in dogs with spontaneous atopic dermatitis.

In humans with atopic dermatitis and in mouse models of IgE-mediated allergic diseases, evidence is mounting that the stratum corneum (SC) provides an important barrier against environmental allergens. At this time, it is not known whether the SC has a similar role in dogs, especially in those with atopic dermatitis. The objectives of this pilot study were to determine whether SC removal led to earlier and stronger sensitization of atopic dogs to Dermatophagoides farinae (Df) house dust mites. Five Maltese-beagle atopic (MBA) dogs were sensitized epicutaneously after the SC was removed with ten tape strips (TS group), while sensitization was done without tape strips in five other MBA dogs (nontape stripping; NTS group). During this 16 week study, sensitization was assessed with allergen-specific IgE serology, intradermal testing with Df allergens and determination of stimulation indices of blood mononuclear cells cultured with Df and stained for CD4 and the activation markers CD25 or CD30. Compared with dogs from the NTS group, those of the TS group exhibited earlier rises in Df-specific IgE serum levels, usually had higher allergen-specific IgE titres, showed higher intradermal test reactivity and had earlier increases and higher percentages of CD25- or CD30-positive activated allergen-specific peripheral CD4-positive T lymphocytes. These observations implicate a role of the SC as a barrier limiting sensitization to exogenous allergens in this experimental atopic dog model.

Determining inflammation and itch pathway activation in patients with atopic dermatitis (AD) is fraught with the inability to precisely assess the age of skin lesions, thus affecting the analysis of time-dependent mediators. To characterize inflammatory events occurring during early experimental acute AD lesions, biopsy samples were collected 6, 24, and 48 hours after epicutaneous application of Dermatophagoides farinae house dust mites to sensitized atopic dogs. The skin transcriptome was assessed using a dog-specific microarray and quantitative PCR. Acute canine AD skin lesions had a significant up-regulation of genes encoding T helper (Th) 2 (e.g., IL4, IL5, IL13, IL31, and IL33), Th9 (IL9), and Th22 (IL22) cytokines as well as Th2-promoting chemokines such as CCL5 and CCL17. Proinflammatory (e.g., IL6, LTB, and IL18) cytokines were also up-regulated. Other known pruritogenic pathways were also activated: there was significant up-regulation of genes encoding proteases cathepsin S (CTSS), mast cell chymase (CMA1), tryptase (TPS1) and mastin, neuromedin-B (NMB), nerve growth factor (NGF), and leukotriene-synthesis enzymes (ALOX5, ALOX5AP, and LTA4H). Experimental acute canine house dust mite-induced AD lesions exhibit an activation of innate and adaptive immune responses and pruritogenic pathways similar to those seen in humans with acute AD, thereby validating this model to test innovative therapeutics modalities for this disease.

Aminoprotect Care (APC) is a novel diet composed of aminoacids, potato proteins and corn starch. The objectives of this study were to determine whether Maltese-Beagle atopic (MBA) dogs hypersensitive to corn exhibited clinical signs and changes in immunological markers after being fed APC. The study was designed as a blinded randomized controlled crossover experiment. Ten MBA dogs with signs of allergy within five days of ingesting corn were selected. Dogs were randomized to be fed either their maintenance diet with corn or APC for five days. After a washout of two weeks, diets were switched. Before and daily during each intervention, skin lesions were graded by an investigator while pruritus was assessed by another. Before and at the end of each intervention, the percentage of circulating CD4+CCR4+, corn-activated CD4+ T-lymphocytes and serum corn-specific IgE levels were measured and ratios of post:pre values calculated. During this trial, pruritus and skin lesions increased significantly in MBA dogs when ingesting corn while no such increase occurred when fed APC. Total, median and maximal pruritus values were significantly higher in MBA dogs ingesting corn compared to APC. There were no significant differences between interventions in the immunological parameters assessed. In summary, even though APC contains corn starch to which corn-sensitive MBA dogs often react, the ingestion of APC did not lead to significant increases in skin lesions or pruritus. Aminoprotect Care might prove valuable for management of food allergies. These experimental observations must be validated in large field studies.

Background – Ceramides are essential stratum corneum (SC) lipids and they play a pivotal role in maintaining effective cutaneous barrier function. Objectives – The present study aimed at determining the effect of a Dermatophagoides farinae house dust mite (Df-HDM) allergen challenge on SC ceramides of atopic dogs experimentally sensitized to these allergens. Animals – Six Df-HDM-sensitized atopic Maltese–beagle dogs were used. Methods – Prechallenge SC was obtained by cyanoacrylate stripping. One week later, the dogs were challenged topically with Df-HDM allergens, which resulted in mild to moderate inflammation 24 h later. Two weeks after challenge, SC of lesional and nonlesional skin was obtained. Finally, SC was collected from challenge sites 2 months after lesion resolution. The different SC lipids were quantified blindly by thin-layer chromatography. Results – Significantly lower amounts of ceramides [AH], [AP], [AS], [NP], [EOP], [NS] and [EOS] were observed in lesional SC compared with prechallenge samples, while no significant effect was found on the amount of other lipids, including cholesterol and free fatty acids. The ceramide profile of nonlesional skin generally showed the same postchallenge reduction pattern. Ceramide amounts returned to normal within 2 months after lesion remission. Conclusion and clinical importance – These findings suggest that the allergic reactions caused by Df-HDM allergens lead to a selective reduction of SC ceramides, not only at sites of inflammation but also at sites away from those of allergen application. There is normalization of ceramide amounts after inflammation subsides. These observations suggest that the deficiency of ceramides observed in canine atopic skin occurs, at least in part, secondary to inflammation.