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1.
Background – Recurrent urticaria (RU) is a common skin disease of horses, but little is known about its pathogenesis. Hypothesis/Objective – The aim of this study was to characterize the inflammatory cell infiltrate and cytokine expression pattern in the skin of horses with RU. Animals – Biopsies of lesional and nonlesional skin of horses with RU (n = 8) and of skin from healthy control horses (n = 8) were evaluated. Methods – The inflammatory cell infiltrate was analysed by routine histology. Immunohistochemistry was used to identify T cells (CD3), B cells (CD79), macrophages (MAC387) and mast cells (tryptase). Expression of T‐helper 2 cytokines (interleukins IL‐4, IL‐5 and IL‐13), a T‐helper 1 cytokine (interferon‐γ), IL‐4 receptor α and thymic stromal lymphopoietin was assessed by quantitative RT‐PCR. Results – In subepidermal lesional skin of RU‐affected horses, increased numbers of eosinophils (P ≤ 0.01), CD79‐positive (P ≤ 0.01), MAC387‐positive (P ≤ 0.01) and tryptase‐positive cells (P ≤ 0.05) were found compared with healthy horses. Subepidermal lesional skin of RU‐affected horses contained more eosinophils (P ≤ 0.05) and tryptase‐positive cells (P ≤ 0.05) compared with nonlesional skin. There was no significant difference in infiltrating cells between nonlesional skin and skin of healthy horses. Expression of IL‐4 (P ≤ 0.01), IL‐13 (P ≤ 0.05), thymic stromal lymphopoietin (P ≤ 0.05) and IL‐4 receptor α (P ≤ 0.05) was increased in lesional skin of RU‐affected horses compared with control horses. Expression of IL‐4 was higher (P ≤ 0.05) in lesional compared with nonlesional RU skin. Conclusions and clinical importance – Analysis of cytokine expression and inflammatory infiltrate suggests that T‐helper 2 cytokines, eosinophils, mast cells and presumptive macrophages play a role in the pathogenesis of equine RU.  相似文献   

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3.
This study investigated the effects of allergic skin disease on the penetration kinetics of hydrocortisone through canine skin in vitro. Full-thickness lesional and nonlesional (normal) skin was removed from the dorsal lumbosacral and dorsocaudal thoracic regions, respectively, of five canine cadavers. The dogs were suspected of having flea allergy dermatitis based on their distribution and types of skin lesions. Nonlesional skin was confirmed to be histologically normal, and the histopathology of the lesional skin was consistent with allergic dermatitis. Excised skin was clipped, mounted in Franz-type diffusion cells, and the transdermal penetration of a saturated, radiolabelled hydrocortisone solution was measured over 30 h. When the penetration data for all five dogs were pooled, a restricted (or residual) maximal likelihood mixed model predicted that the permeability coefficient and pseudosteady-state flux of hydrocortisone was more than twice as great (95% confidence interval 1.55-2.71 times as great; P < 0.0001) through lesional compared with nonlesional skin. There was no significant difference in the lag time for hydrocortisone penetration through lesional compared with nonlesional skin of the dogs. This study has confirmed that the transdermal penetration of hydrocortisone may be altered, typically increased twofold, but could be as high as 10-fold, through lesional compared with nonlesional skin of dogs with suspected flea allergy dermatitis. This is likely to be affected by variables such as disease severity, concurrent infections and interindividual differences in skin characteristics.  相似文献   

4.
Chemokines are important regulators of the selective recruitment of inflammatory cells into sites of allergic inflammation. Since canine atopic dermatitis (AD) shares many clinical features of human AD, patterns of chemokine production in dogs may also be similar with those in humans. The aim of this study was to examine mRNA expression of CCL27 and CCL28 in lesional skin of dogs with AD to demonstrate similarity of chemokine production with human counterparts. RNA was extracted from skin biopsy specimens of 12 dogs with AD. The mRNA expression of CC chemokines (CCL4, CCL19, CCL20, CCL21, CCL24, CCL27 and CCL28) was analyzed by quantitative real-time PCR and was compared between lesional and non-lesional skin. Seven types of chemokines examined were constitutively expressed in both lesional and non-lesional skin. It was found that mRNA expression levels of CCL27 and CCL28 among the chemokines were significantly different between lesional and non-lesional skin (P<0.05). Expression level of CCL27 mRNA in lesional skin was significantly lower than that in non-lesional skin. On the other hand, CCL28 mRNA expression in lesional skin was found to be higher than that in non-lesional skin. These results suggest that CCL28 but not CCL27 may play important roles in immunopathogenesis of canine AD, indicating that experimental canine study may provide additional information that can be extrapolated to human AD.  相似文献   

5.
Atopic dermatitis (AD) is very common in dogs, but its pathogenesis is not yet fully understood. It has been suggested that a Th2‐dominant status may be associated with the occurrence of canine AD. IL‐12 is thought to be important for the differentiation of Th1 cells. The IL‐12 receptor β2 (IL‐12Rβ2) gene is considered to play a critical role in signal transduction and is attracting attention as one of the causative genes of AD in humans. The purpose of this study was to investigate the relationship between IL‐12Rβ2 gene expression and canine AD. The canine IL‐12Rβ2 gene was cloned by RT‐PCR and its nucleotide sequences were determined. Canine IL‐12Rβ2 showed 76.8% homology at the amino acid level with human IL‐12Rβ2, and its structural motifs were well conserved. cDNA with a 91 bp deletion including the transmembrane region was also cloned, which consequently produced a frame shift and an early stop codon. The deletion region corresponded to exon 14 of the human IL‐12Rβ2 gene on chromosome 1. The expression of deleted canine IL‐12Rβ2 mRNA in phytohemagglutinin‐stimulated peripheral blood mononuclear cells was examined in seven healthy dogs and 11 AD dogs. Both deleted and intact mRNAs were expressed at constant ratios in healthy and AD dogs. The results indicate that the deletion of the transmembrane region is not associated with the occurrence of AD, and that the expression of the deleted mRNA may be constitutive and produced by alternative splicing. Funding: Self‐funded.  相似文献   

6.
Stem cell factor (SCF) influences mast cell activation and inflammatory mediator release, and is elevated in tissues undergoing allergic inflammation. Wheal formation in response to the injection of SCF or anti-immunoglobulin (Ig)E antibody injection was compared between normal (n = 10) and nonlesional atopic (n = 10) canine skin. In situ SCF secretion was compared between lesional and nonlesional skin using immunohistochemistry. Histamine release by skin cell suspensions after stimulation with SCF, concanavalin A (ConA) or rabbit anticanine IgE antibodies was compared between normal and atopic dogs. All dogs exhibited strong responses to intradermal SCF injection at 10 and 50 ng mL(-1). Atopic dogs had significantly (P = 0.002) larger wheal responses to anti-IgE than normal dogs; but there was no difference in numbers of skin mast cells bearing IgE as detected by immunohistochemistry. Only atopic dogs exhibited interstitial deposition of SCF in both lesional and nonlesional skin specimens. Median histamine release stimulated by SCF in the absence of IgE from lesional skin cells was higher in atopic than normal dogs (P = 0.04). These experiments suggest that dermal SCF secretion could potentiate histamine release following IgE receptor cross-linking and thus, could be one of the explanations for the inherent mast cell hyperexcitability observed in canine atopic dermatitis.  相似文献   

7.
The purpose of this study was to determine whether tacrolimus ointment (Protopic) decreased the severity of localized lesions of canine atopic dermatitis (AD). Twenty dogs with AD were enrolled if they exhibited skin lesions localized to both front metacarpi. Each foot was randomized to be treated either with 0.1% tacrolimus or placebo (vaseline) ointment twice daily for 6 weeks. The nature of treatment for each foot lesion was concealed from the clinician. Before, and every 2 weeks during the study, erythema, lichenification, oozing and excoriations each were graded on a 10‐point scale (maximal total score: 40). The primary outcome measures consisted of the percentage reduction from baseline of lesional scores, and the number of subjects whose scores had decreased by 50% or greater by the end of the study. Intent‐to‐treat analyses were used. At the beginning of the study, lesional scores were not significantly different between treatment groups. After 6 weeks, the percentage reduction from baseline scores was higher for tacrolimus‐treated sites [median: 63% (95% CI: 39–67)] than for placebo‐treated feet [3% (‐2‐13)] (paired t‐test; P < 0.0001). When tacrolimus was applied, lesions decreased by 50% or greater in 15 dogs (75%), while this benchmark was not reached for any placebo‐treated feet (Fisher's exact test; P < 0.0001). Adverse drug events consisted of minor irritation in some dogs treated with tacrolimus. Results of this randomized, controlled trial suggest that the daily application of 0.1% tacrolimus ointment is useful for reducing the severity of localized skin lesions of canine AD. Funding: Self‐funded.  相似文献   

8.
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.  相似文献   

9.
Background – Antimicrobial peptides (AMPs) are small immunomodulatory peptides produced by epithelial and immune cells. β‐Defensins (BDs) and cathelicidins (Caths) are the most studied AMPs. Recently, increased cutaneous expression of AMPs was reported in atopic humans and in beagles with experimentally induced atopy. Hypothesis/Objectives – Our goal was to analyse mRNA expression and protein levels of canine (c)BD1‐like, cBD2‐like/122, cBD3‐like, cBD103 and cCath in healthy and naturally affected atopic dogs, with and without active skin infection, along with their distribution in the epidermis using indirect immunofluorescence. Animals – Skin biopsies were taken from 14 healthy and 11 atopic privately owned dogs. Methods – The mRNA levels of cBD1‐like, cBD2‐like/122, cBD3‐like, cBD103 and cCath were quantified using quantitative real‐time PCR. The protein levels of cBD3‐like and cCath were analysed by relative competitive inhibition enzyme‐linked immunosorbent assay, while the distributions of cBD2‐like/122, cBD3‐like and cCath were detected by indirect immunofluorescence. Results – Dogs with atopic dermatitis had significantly greater mRNA expression of cBD103 (P = 0.04) than control dogs. Furthermore, atopic skin with active infection had a higher cBD103 mRNA expression (P = 0.01) and a lower cBD1‐like mRNA expression (P = 0.04) than atopic skin without infection. No significant differences in protein levels (cBD3‐like and cCath) or epidermal distribution of AMPs (cBD2‐like/122, cBD3‐like and cCath) were seen between healthy and atopic dogs. Conclusions and clinical importance – Expression of cBD103 mRNA was greater, while expression of cBD1‐like mRNA was lower in dogs with atopic dermatitis that had active infections. Work is needed to clarify the biological mechanisms and possible therapeutic options to maintain a healthy canine skin.  相似文献   

10.
Background – Keratinocytes in the hair follicle bulge region have a high proliferative capacity, with characteristics of epithelial stem cells. This cell population might thus be an ideal source for generating the interfollicular epidermis in a canine skin equivalent. Hypothesis/Objectives – This study was designed to determine the ability of canine hair follicle bulge cell‐enriched keratinocytes to construct canine living skin equivalents with interfollicular epidermis in vitro. Animals – Four healthy beagle dogs from a research colony. Methods – Bulge cell‐enriched keratinocytes showing keratin 15 immunoreactivity were isolated from canine hair follicles and cultured on dermal equivalent containing canine fibroblasts. Skin equivalents were subjected to histological, immunohistochemical, western blot and RT‐PCR analyses after 10–14 days of culture at the air–liquid interface. Results – The keratinocyte sheets showed an interfollicular epidermal structure comprising four to five living cell layers covered with a horny layer. Immunoreactivities for keratin 14 and desmoglein 3 were detected in the basal and immediate suprabasilar layers of the epidermis, while keratin 10 and desmoglein 1 occurred in more superficial layers. Claudin 1 immunoreactivity was seen in the suprabasalar layer of the constructed epidermis, and filaggrin monomers and loricrin were detected in the uppermost layer. Basal keratinocytes in the skin equivalent demonstrated immunoreactivity to antibodies against basement membrane zone molecules. Conclusions and clinical importance – A bulge stem cell‐enriched population from canine hair follicles formed interfollicular epidermis within 2 weeks in vitro, and thus represents a promising model for regenerative therapy of canine skin.  相似文献   

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12.
A monoclonal antibody to canine thymus and activation-regulated chemokine (TARC/CCL17) was developed to examine the association of TARC with the immunopathogenesis of canine atopic dermatitis (AD). Recombinant canine TARC was prepared using an E. coli expression system. Results of transwell chemotaxis assay demonstrated that the recombinant canine TARC showed chemotactic activity for canine lymphoid cells expressing CC chemokine receptor 4 (CCR4). Mice were then immunized with the recombinant canine TARC to obtain monoclonal antibodies. Among the monoclonal antibodies thereby obtained, one monoclonal antibody (CTA-1) was found to react with both recombinant and authentic canine TARC in ELISA and flowcytometric assays, respectively. Immunohistochemical analysis using the monoclonal antibody CTA-1 demonstrated that keratinocytes were major TARC producing cells in lesional skin of dogs with AD.  相似文献   

13.
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14.
Background – Filaggrin (FLG) is a key protein for skin barrier formation and hydration of the stratum corneum. In humans, a strong association between FLG gene mutations and atopic dermatitis has been reported. Although similar pathogenesis and clinical manifestation have been argued in canine atopic dermatitis, our understanding of canine FLG is limited. Hypothesis/Objectives – The aim of this study was to determine the structure of the canine FLG gene and to raise anti‐dog FLG antibodies, which will be useful to detect FLG protein in dog skin. Methods – The structure of the canine FLG gene was determined by analysing the publicly available canine genome DNA sequence. Polyclonal anti‐dog FLG antibodies were raised based on the canine FLG sequence analysis and used for defining the FLG expression pattern in dog skin by western blotting and immunohistochemistry. Results – Genomic DNA sequence analysis revealed that canine FLG contained four units of repeated sequences corresponding to FLG monomer protein. Western blots probed with anti‐dog FLG monomer detected two bands at 59 and 54 kDa, which were estimated sizes. The results of immunohistochemistry showed that canine FLG was expressed in the stratum granulosum of the epidermis as a granular staining pattern in the cytoplasmic region. Conclusions and clinical importance – This study revealed the unique gene structure of canine FLG that results in production of FLG monomers larger than those of humans or mice. The anti‐dog FLG antibodies raised in this study identified FLG in dog skin. These antibodies will enable us to screen FLG‐deficient dogs with canine atopic dermatitis or ichthyosis.  相似文献   

15.
Background – Interleukin‐31 (IL‐31) is a member of the gp130/interleukin‐6 cytokine family that is produced by cell types such as T helper 2 lymphocytes and cutaneous lymphocyte antigen positive skin homing T cells. When overexpressed in transgenic mice, IL‐31 induces severe pruritus, alopecia and skin lesions. In humans, IL‐31 serum levels correlate with the severity of atopic dermatitis in adults and children. Hypothesis/Objective – To determine the role of IL‐31 in canine pruritus and naturally occurring canine atopic dermatitis (AD). Animals – Purpose‐bred beagle dogs were used for laboratory studies. Serum samples were obtained from laboratory animals, nondiseased client‐owned dogs and client‐owned dogs diagnosed with naturally occurring AD. Methods – Purpose‐bred beagle dogs were administered canine interleukin‐31 (cIL‐31) via several routes (intravenous, subcutaneous or intradermal), and pruritic behaviour was observed/quantified via video monitoring. Quantitative immunoassay techniques were employed to measure serum levels of cIL‐31 in dogs. Results – Injection of cIL‐31 into laboratory beagle dogs caused transient episodes of pruritic behaviour regardless of the route of administration. When evaluated over a 2 h period, dogs receiving cIL‐31 exhibited a significant increase in pruritic behaviour compared with dogs that received placebo. In addition, cIL‐31 levels were detectable in 57% of dogs with naturally occurring AD (≥13 pg/mL) but were below limits of quantification (<13 pg/mL) in normal, nondiseased laboratory or client‐owned animals. Conclusions – Canine IL‐31 induced pruritic behaviours in dogs. Canine IL‐31 was detected in the majority of dogs with naturally occurring AD, suggesting that this cytokine may play an important role in pruritic allergic skin conditions, such as atopic dermatitis, in this species.  相似文献   

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17.
Background – It is unproven that all dogs harbour Demodex mites in their skin. In fact, several microscopic studies have failed to demonstrate mites in healthy dogs. Hypothesis/Objectives – Demodex canis is a normal inhabitant of the skin of most, if not all, dogs. This hypothesis was tested using a sensitive real‐time PCR to detect Demodex DNA in the skin of dogs. Animals – One hundred dogs living in a humane society shelter, 20 privately owned and healthy dogs and eight dogs receiving immunosuppressive or antineoplastic therapy. Methods – Hair samples (250–300 hairs with their hair bulbs) were taken from five or 20 skin locations. A real‐time PCR that amplifies a 166 bp sequence of the D. canis chitin synthase gene was used. Results – The percentage of positive dogs increased with the number of sampling points. When a large canine population was sampled at five cutaneous locations, 18% of dogs were positive for Demodex DNA. When 20 skin locations were sampled, all dogs tested positive for mite DNA. Our study indicates that Demodex colonization of the skin is present in all dogs, independent of age, sex, breed or coat. Nevertheless, the population of mites in a healthy dog appears to be small. Demodex DNA was amplified from all 20 cutaneous points investigated, without statistically significant differences. Conclusions and clinical importance – Using a real‐time PCR technique, Demodex mites, albeit in very low numbers, were found to be normal inhabitants of haired areas of the skin of healthy dogs.  相似文献   

18.
Background – In dogs, flea infestation (FI), flea bite hypersensitivity (FBH) and canine atopic dermatitis (CAD) have been mainly characterized by their lesions but never by their pruritus. In clinical practice, many of these dogs exhibit only pruritus. Hypothesis/Objectives – The purpose of this study was to evaluate the characteristics of pruritus in these dermatoses and their potential usefulness for diagnosis. Animals – Dogs included were selected from the Oniris clinical data. Cases were selected in which the dogs had only one of the three dermatoses diagnosed. The diagnosis of CAD was based on Prélaud’s criteria and positive intradermal tests except flea; for FBH by compatible clinical signs and a response to an intradermal test with flea allergen; and for FI by the presence of fleas. Moreover, in each group, other primary pruritic skin diseases were excluded. Methods – Location, behavioural manifestations, seasonality and quantification of the pruritus were evaluated. The statistical analysis used chi‐squared test with a P‐value <0.05. Results – Three hundred and forty‐six dogs were analysed, 91 with CAD, 110 FI and 145 FBH. The period (season) of onset was not statistically different either for each dermatosis or among the three dermatoses. Some locations were highly specific for one dermatosis as follows: ventral abdomen/medial surface of thigh (chewing) and radius/carpus/tibia/tarsus (chewing) in FI; back/dorsolumbar area (chewing) and tail (chewing) in FBH; and paws (chewing/licking) and face/neck (rubbing) in CAD. Conclusions and clinical importance – Some features of pruritus could be suggestive of the causal disease, with possible diagnostic value in pruritic dogs.  相似文献   

19.
CC chemokine receptor 4 (CCR4) is a G protein-coupled seven transmembrane receptor that is selectively expressed on Th2 cells and plays an important role in the trafficking of Th2 cells into inflammatory sites. In this study, a full-length canine CCR4 cDNA was cloned and characterized in order to examine the potential role of CCR4 in allergic responses that produce skin lesions in canine atopic dermatitis (AD). The canine CCR4 cDNA reported in this study contained an open reading frame of 1083 nucleotides encoding 360 amino acids. The predicted amino acid sequence of canine CCR4 showed 91.9, 85.3 and 84.5% similarity with those of the human, mouse and guinea pig counterparts, respectively. Expression of CCR4 mRNA was detected in various tissues including thymus, spleen, heart, small intestine and lymph node. Furthermore, it was found that CCR4 mRNA was preferentially expressed in lesional skin of dogs with AD, together with the mRNA of thymus and activation-regulated chemokine (TARC), which is a ligand for CCR4. The present study demonstrates that CCR4 contributes strongly to the immunopathogenesis of canine AD.  相似文献   

20.
Background – Dogs and humans with atopic dermatitis (AD) are predisposed to colonization and recurrent infection with Staphylococcus spp. Studies in humans suggest that staphylococcus‐specific immunoglobulin E (IgE) plays a key role in disease pathogenesis. Few such studies have been undertaken in dogs. Hypothesis/Objectives – The aim of this study was to compare levels of staphylococcus‐specific IgE and immunoglobulin G (IgG) in dogs with AD, nonatopic dogs with staphylococcal pyoderma, and nonatopic and noninfected control dogs. Animals – Sera were collected from 108 dogs with AD, 39 nonatopic dogs with staphylococcal pyoderma secondary to different underlying conditions, 67 age‐matched nonatopic control dogs, and nine control dogs reared in minimal disease conditions. Methods – Serum Staphylococcus pseudintermedius‐specific IgE and IgG antibodies were measured by enzyme‐linked immunosorbent assay. Results – Dogs with AD had significantly higher levels of anti‐staphylococcal IgE than nonatopic dogs with staphylococcal pyoderma and the two groups of control dogs. Levels of anti‐staphylococcal IgG were significantly higher in atopic dogs and nonatopic dogs with pyoderma compared with nonatopic control dogs and control dogs reared in minimal disease conditions, but there was no significant difference in levels of anti‐staphylococcal IgG between dogs with AD and nonatopic dogs with pyoderma. Conclusions and clinical importance – A significantly increased IgE response to S. pseudintermedius antigens in atopic dogs suggests an immunopathogenic role for anti‐staphylococcal IgE. The finding of elevated IgE and IgG in atopic dogs is also important as a prelude to studies on antigenic specificity and possible correlations with disease phenotype.  相似文献   

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