Veterinary dermatology最新文献

Background: In bearded dragons (Pogona vitticeps), nannizziomycosis can cause skin lesions, ulceration and lethargy. Formally known as yellow fungal disease (YFD), nannizziomycosis has traditionally been attributed to various Nannizziopsis spp. identified via culture and referred to as Chrysosporium anamorph of Nannizziopsis (CANV).

Hypothesis/objectives: We hypothesized that the presence of Nannizziopsis does not always lead to nannizziomycosis, and that this disease may be caused by multiple pathogens or interactions between microbes (known as the cross-kingdom effect).

Animals: Thirty-one bearded dragons with suspected nannizziomycosis (unhealthy group) and 20 healthy bearded dragons.

Materials and methods: Next-generation sequencing (NGS) was used to explore the microbial interactions within the cutaneous microbiota of 51 bearded dragons.

Results: One unidentified species within the Nannizziopsis genus (Nannizziopsis sp.) was included in a co-occurrence analysis between 877 bacterial and 78 fungal species in the unhealthy group. Forty-one positive co-occurrences with Nannizziopsis spp. were seen, including Salmonella enterica (p = 0.001), an unidentified species within the Clostridiales order (p < 0.001) and a fungal species from the Cladosporium genus (p = 0.0261). Forty-nine negative interactions with Nannizziopsis spp. were seen, including Bifidobacterium adolescentis (p = 0.0478) and Corynebacterium durum (p = 0.0478).

Conclusions and clinical relevance: These findings suggest that commensal microbes may change in response to counteract Nannizziopsis, while pathogenic microbes may help facilitate it. Further research should clarify microbial interactions in bearded dragons with nannizziomycosis.

Background: The identification of the activation of the mammalian target of rapamycin (mTOR) signalling pathway as a frequent molecular event in canine cutaneous papillomas (CPs) has provided the rational foundation to explore novel molecular-targeted therapies. Recent evidence indicates that metformin reduces the size of CPs in mice by inhibiting the mTOR signalling pathway. These effects require the expression of the organic cation transporter 3 (OCT3/SLC22A3), a well-known metformin uptake transporter.

Hypothesis/objectives: The aim of the present study was to characterise the expression pattern of the metformin uptake transporter OCT3 in canine samples of CP that have shown activation of the mTOR signalling pathway in order to predict if this hyperplastic epidermal lesion is potentially sensitive to metformin.

Methods: The expression of OCT3 was evaluated by immunohistochemical investigation in sections of a previously constructed tissue microarray containing 28 samples of canine CP and compared with that previously evaluated for the mTOR activation marker pS6.

Results: OCT3 was highly expressed in the membrane and cytoplasm of the basal and suprabasal epidermal cells in all samples of canine CP. This OCT3 expression was localised at similar epidermal compartments to those observed for pS6.

Conclusions and clinical relevance: These results show that canine CPs exhibit the expression of surrogate markers that suggest sensitivity to metformin, such as upregulated OCT3 and pS6 expression. Taken together, these findings provide the rationale for the early assessment of the use of metformin as a mechanism-based therapeutic approach for treating canine patients with persistent or multiple CPs.

Background: Canine aural cholesteatoma (more appropriately named tympanokeratoma) is an epidermoid cyst whose aetiopathogenesis remains poorly recognised in veterinary medicine. There are a few reports published, possibly because it may be underdiagnosed.

Objectives: To characterise the clinical aspects of dogs with tympanokeratoma, to describe the otoendoscopic, advanced imaging and histopathological findings of tympanokeratoma and to report the best approach to diagnose canine auricular tympanokeratoma in a retrospective study.

Material and methods: Of 890 dogs with suspected tympanokeratoma and otitis media, 100 animals underwent advanced imaging and otoendoscopy at radiology and dermatology reference centres in Brazil.

Results: Most affected dogs were male (71%) neutered (95%) with an average age of 6.8 years. Ninety-one of the 100 affected dogs were brachycephalic. Otitis externa (OE; 81%) was the main non-neurological manifestation observed. The main neurological clinical manifestations observed were: "head tilt" (66%), ataxia (31%) and nystagmus (25%). Advanced imaging findings could not propose a presumptive diagnosis of tympanokeratoma in 60 of 100 (60%) of the dogs. The absence of tympanic membrane and the presence of a dense pearly yellowish material resembling keratin in the tympanic bulla, after myringotomy, was the main otoendoscopic finding. The advanced imaging findings did not correlate with otoendoscopy and histopathological findings in more than half of the dogs.

Conclusions and clinical relevance: Tympanokeratoma should be suspected in brachycephalic dogs with OE and peripheral vestibular syndrome, and samples of keratinous material from the middle ear associated with histopathological results may be the best approach for the diagnosis.

Background: Canine atopic dermatitis (cAD) is a chronic, inflammatory, multifactorial and pruritic disease. The presence of skin barrier impairment (e.g. filaggrin alterations), along with abnormal immune responses, can negatively impact cutaneous barrier function.

Objectives: To evaluate the filaggrin 2 (FLG2) expression in atopic dogs before and after the administration of oclacitinib maleate.

Animals: Sixteen privately owned dogs with a diagnosis of cAD and 10 healthy control dogs.

Materials and methods: Oclacitinib maleate monotherapy at 0.5 mg/kg, orally, twice-daily for the first 14 days and once-daily for 16 additional days, was administered to the atopic dogs. Skin biopsies from lesional and nonlesional skin were obtained from atopic dogs on Day(D)0 and D30 and from the same anatomical locations from the control group on D0. Immunohistochemical investigation was performed using a primary custom-made anti-canine-filaggrin 2 polyclonal antibody. Immunolabelled slides were scanned and FLG2 expression was measured. Data were analysed and a p-value ≤0.05 was considered statistically significant.

Results: There was a higher FLG2 expression in control skin when compared with atopic skin (lesional and nonlesional) on D0 (p = 0.033). FLG2 expression comparison between control and D30 (nonlesional) did not show a significant difference (p = 0.509). A significant increase in FLG2 expression in atopic nonlesional skin on D30 compared with nonlesional skin on D0 was also observed (p = 0.014).

Conclusions and clinical relevance: Oclacitinib maleate could have a positive impact on cutaneous barrier structure, improving FLG2 expression by decreasing inflammation and cutaneous trauma.

Background: Epicutaneously house dust mite-sensitised (HDM-S) healthy dogs are commonly used as canine atopic dermatitis (cAD) models; however, the exact mechanisms of HDM-induced AD immune activation in HDM-S and HDM-nonsensitised (NS) dogs remain unclear.

Objectives: To characterise the inflammatory and pruritogenic transcriptome of acute epicutaneous HDM-induced skin lesions at 6 h and 24 h in HDM-NS and HDM-S dogs; untreated skin at 0 h from each dog served as control.

Animals: Six HDM-S and six HDM-NS laboratory beagles.

Materials and methods: Processed expression data from GEO deposited by Schamber et al. (G3 (Bethesda), 2014, 4 and 1787) (GSE58442) were downloaded and analysed using R and the Bioconductor package. Significance analysis was performed with the limma package; genes with false discovery rate <0.05 and fold-change ≤/≥1.5 were considered significantly differentially expressed (DEGs).

Results: A 2D principal component analysis revealed no clear separation between HDM-NS and HDM-S dogs at 6 h and 24 h time points. HDM-induced skin lesions in sensitised and nonsensitised dogs at the 24 h time point showed significant upregulation of T helper cell (Th)2 genes (interleukin [IL]-4R, IL-5, IL-13, CCL13 and CCL17), as well as proinflammatory- (LTB, IL-1A and IL-18), Th1- (CXCL10, OASL and MX-1) and Th17-related markers (IL-17B, IL-17F, CCL19 and CCL20). The key Th22-related maker, IL-22, was upregulated only in the HDM-S group at the 24 h time point. Both groups at 24 h featured significant upregulation of several noncytokine pruritogens, such as trypsin, chymase, cathepsin S, periostin and neuromedin B.

Conclusions and clinical relevance: Taken together, we establish that epicutaneous HDM patch application induces immune changes in HDM-NS dogs with Th2 dominance and activates several itch-promoting pathways.

Background: Erythritol, a sugar alcohol, has been reported to suppress the in vitro growth of Staphylococcus pseudintermedius and Staphylococcus coagulans.

Objectives: To determine whether erythritol suppresses the growth of Staphylococcus hyicus, a major pathogen causing porcine exudative epidermitis, and to investigate the molecular mechanisms involved in erythritol-induced S. hyicus growth suppression.

Materials and methods: An in vitro turbidity assay was performed to assess the effect of erythritol on the growth of 26 S. hyicus strains, including a reference strain JCM 2423 and the 25 wild strains isolated from pigs. Differentially expressed genes in response to erythritol in JCM 2423 were identified by RNA-Seq and quantitative reverse transcription-PCR. The impact of trehalose, glucose and arginine supplementation on erythritol-induced growth suppression of the 25 S. hyicus wild strains was also investigated.

Results: Erythritol suppressed the in vitro growth of JCM 2423 and the 25 S. hyicus wild strains. Moreover, erythritol upregulated the transcription of multiple genes in JCM 2423, including those encoding ATP-binding cassette transporter enzymes (potB, potC and potD), arginine biosynthetic pathway enzymes (argF, argG and argH), l-arginine deiminase pathway enzymes (arcA, arcC and arcD), fatty acid metabolism pathway enzymes (fabH and fabF) and trehalose metabolism-related proteins (treC, treR and treP). Supplementation of trehalose or glucose in aerobic conditions or arginine supplementation in anaerobic conditions restored in vitro growth of the 25 S. hyicus wild strains treated by erythritol.

Conclusions and clinical relevance: Erythritol suppresses the in vitro growth of S. hyicus by inhibiting intracellular sugar and arginine metabolism under aerobic and anaerobic conditions, respectively.

Background: Sporotrichosis is a chronic, mycotic infection caused by fungi of the genus Sporothrix. Zoonotic sporotrichosis occurs mainly through S. brasiliensis transmission, resulting from the organism's traumatic introduction via scratches or bites, or contact with exudate from contaminated cats. The loop-mediated isothermal amplification (LAMP) assay is a viable molecular alternative for detecting Sporothrix in veterinary low-resource settings.

Hypothesis/objectives: To develop a LAMP method for Sporothrix identification using fungal isolates and clinical samples of domestic cats (Felis catus).

Materials and methods: DNA samples were collected from Sporothrix isolates and clinical samples of cats positive for sporotrichosis. Six LAMP primers were designed to amplify the 28S ribosomal RNA region of S. schenckii and S. brasiliensis. Colorimetric assay and agarose gel electrophoresis were used to analyse the LAMP amplification. Isolated samples were sequenced using the Sanger technique, employing the amplification of genetic material by conventional PCR with the external primers of LAMP.

Results: A sensitivity of 96.77% for isolated Sporothrix samples was found using the LAMP method, confirmed by Sanger sequencing. The detection limit of LAMP was between 1 and 10 pg of Sporothrix DNA according to the sample matrix. LAMP showed a sensitivity of 100% using blood samples, 77.78% using intranasal swabs and 92.31% and 100% using swab and adhesive tape samples of cutaneous lesions, respectively.

Conclusions and clinical relevance: These findings support a simple and quick LAMP-based screening tool for detecting Sporothrix in isolated and clinical samples. This accessible test can aid in disease management when standard culture analysis is unavailable or impractical.

Background: The types of skin lesions in canine epitheliotropic cutaneous T-cell lymphoma (ECTCL) vary markedly; however, the mechanisms underlying this diversity remain unclear. Human ECTCL exhibits clonal heterogeneity, with different clones of neoplastic lymphocytes being observed in skin lesions from the same patients. Therefore, we hypothesised that diversity in skin lesions may be attributed to clonal heterogeneity.

Objectives: To evaluate clonality and its association with skin lesions.

Materials and methods: PCR for T-cell receptors was performed on 25 formalin-fixed paraffin-embedded lesional skin samples derived from eight ECTCL cases. A fragment analysis was performed to establish whether clonal patterns were identical or nonidentical between lesions. The associations of clonal patterns with the types and histopathological features of skin lesions were investigated by statistical analyses. A transcription analysis was also conducted to examine the expression of recombination-activating gene (RAG)1 in skin lesions.

Results: The fragment analysis identified only one case with an identical clonal pattern in all skin lesions. Nonidentical clonal patterns were detected in the seven other cases. Clonal patterns were not associated with the types of skin lesions or histopathological features. The transcription analysis did not detect RAG1 in any skin lesions.

Conclusions and clinical relevance: The present study is the first to report clonal heterogeneity in canine ECTCL that was not associated with the clinical or histopathological features of skin lesions. The results obtained also suggested that clonal heterogeneity originated not in the skin.