Non-invasive evaluation of cytokine expression using the cerumen of dogs with otitis externa.

The development of a non-invasive method to analyze cytokine expression in the skin will provide further understanding of inflammatory skin disorders. This study aimed to evaluate cytokine expression in the skin through cerumen swabbing in dogs with otitis externa (OE) and to investigate whether increased cytokine expression in infected OE reflects the inflammatory status of the ear canal. Three groups consisting of control dogs (n = 24), dogs with ceruminous Malassezia OE (n = 25), and dogs with suppurative bacterial OE (n = 15) were included in the study. The concentrations of keratinocyte-derived cytokines including Interleukin (IL)-8/chemokine ligand (CXCL)8, IL-10, IL-6, Tumor necrosis factor (TNF)-α, and IL-1ß in the cerumen of the ear canal of the included patients were analyzed using commercial ELISA kits. Additionally, correlations between cytokine levels and cytology scores (of Malassezia yeasts, cocci/rod-shaped bacteria, and inflammatory cells) were assessed. IL-8/CXCL8 concentrations were significantly higher in dogs with ceruminous Malassezia OE and dogs with suppurative bacterial OE than in control dogs. Furthermore, IL-8/CXCL8 concentrations positively correlated with Malassezia scores in dogs with ceruminous OE (r = 0.630) and with bacterial scores in dogs with suppurative OE (r = 0.601). In addition, increased expression of IL-6 and IL-1ß were detected in dogs with suppurative bacterial OE compared to those with Malassezia OE and control dogs, and showed positive correlation with inflammatory cell scores IL-6 r = 0.520, IL-1ß; r = 0.680). Therefore, keratinocyte-derived cytokines could be evaluated using non-invasive methods such as cerumen swabbing in dogs with OE.

Hematological differentiation of bladder rupture and complete/partial urethral obstruction in castrated Hanwoo (Korean indigenous cattle) with urolithiasis.

This case report describes the hematological and radiological examination of urinary bladder rupture and complete urethral obstruction. associated with urolithiasis in Hanwoo. Hyponatremia, hypochloremia, azotemia, and hyperglycemia were observed in both urethral obstruction and urinary bladder rupture. However, cattle with urethral obstruction showed hyperkalemia and mild hyperglycemia, whereas cattle with bladder rupture showed marked hyperglycemia and normal potassium levels. In ultrasonography, the urethral obstruction showed a dilated bladder with a thick bladder wall. In contrast to previous literature, in this study, severe electrolyte changes such as severe hyponatremia, hypochloremia, and hyperkalemia occurred in a case of complete urethral obstruction.

A Canine Case of Nocardia africana Infection Detected by Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry.

Nocardiosis, a rare infectious disease in dogs and cats, is caused by Gram-positive aerobic actinomycetes of the genus Nocardia. A one-year-old castrated male Great Dane was presented with clinical signs of an ulcerated nodule on the right ear, which was observed after two weeks of treatment with cyclosporine and prednisolone due to idiopathic hepatitis. Cytological examination revealed pyogranulomatous inflammatory cells and blanched filamentous rods. To detect infectious agents, serosanguinous discharge of the nodule was subjected to bacterial and fungal cultures. For phenotyping of the infectious agents, colonies on blood agar culture plates were further analyzed by matrix-assisted laser desorption ionization (MALDI)-time-of-flight (TOF) mass spectrometry (VITEK MS). The MALDI-TOF spectra were identified as N. africana. Thus, the present case was diagnosed as cutaneous nocardiosis. The skin lesions of ulcerated nodules with fistulous tracts were gradually resolved by the administration of meropenem (8 mg/kg TID, IV) and doxycycline (5 mg/kg BID, PO). Although complete resolution of the skin lesions was observed on day 91 after the initial presentation, single administration of doxycycline was continued until day 198 after the initial presentation to prevent recurrence. To the best of our knowledge, this is the first report of Nocardia africana infection in a dog. In addition, our results show that MALDI-TOF mass spectrometry analysis could be a useful tool for the detection of Nocardia. spps.

A case of leukaemia cutis in a dog with T-cell chronic lymphocytic leukaemia.

Leukaemia cutis (LC) is the infiltration of neoplastic leukocytes into the skin, characterised by haemorrhagic papules, nodules, and plaques. LC has been reported in human leukaemia patients, but it is extremely rare in dogs. A 13-year-old spayed female Golden Retriever that was previously diagnosed with chronic lymphocytic leukaemia was managed with chlorambucil (20 mg/m2 orally, every 2 weeks) and prednisolone (2 mg/kg orally, every other day) for 8 months; however, immunosuppression was temporarily discontinued because of a bacterial urinary tract infection. Cutaneous signs, including multifocal ecchymosis and white plaques, appeared 1 month after cessation of chemotherapy. Histopathological examination revealed small- to intermediate-sized lymphocytes with mild atypia in a perivascular to interstitial pattern within the superficial dermis. The bands of atypical cells within the superficial dermis were strongly and extensively positive for CD3 on immunohistochemistry. Polymerase chain reaction analysis of the biopsied skin revealed clonal rearrangement of the T-cell receptor gamma locus gene. Given the evidence of clinical signs, peripheral immunophenotyping, histopathology, immunohistochemistry, and clonal gene arrangement, LC was diagnosed. The lesions disappeared when chemotherapy was restarted but were occasionally observed when chemotherapy was stopped. To the authors' best knowledge, this is the first case report of LC in a dog.

Effects of age, sex, and breed on the composition of free extractable ceramides in the stratum corneum of healthy dogs.

Ceramide (CER), an important component of the extracellular lamellar lipids in the stratum corneum (SC), plays a critical role in maintaining the cutaneous barrier function. This study aimed to determine whether the quantity of free extractable SC CERs in dogs was affected by the age, sex, or breed. Fifty-eight dogs from the breeds Shiba Inu, beagle, miniature dachshund, shih tzu, and golden retriever, without any history of skin problems, were enrolled in this study. Lipid extracts from the SC were subjected to high-performance thin-layer chromatography to quantify the free extractable CERs. There were weak negative correlations between the age and the amount of free extractable CERs, CER [NP] (non-hydroxy fatty acids linked to phytosphingosines), CER [AS/NH] (α-hydroxy fatty acids linked to sphingosines/non-hydroxy fatty acids linked to 6-hydroxysphingosines), and CER [AP] (α-hydroxy fatty acids and phytosphingosines). There were no significant sex- or breed-related differences in the amounts of free extractable SC CERs in the dogs. These findings imply that aging causes a decline in the amount of free extractable SC CERs in dogs, similar to that observed in humans. The sex or breed of the dogs investigated in this study did not influence the amount of free extractable SC CERs.

Changes in the Serum Protein Electrophoresis Profile in Dogs With Pyometra.

Serum proteins are involved in the regulation of inflammation, and therefore, serum protein profiling provides important insights in diverse inflammatory reactions. Accordingly, concentrations of single APPs, such as the C-reactive protein (CRP), serum amyloid A (SAA), and haptoglobin (Hp), have been described as indicators of inflammatory response in canine pyometra. However, there is little information regarding the overall serum protein profile obtained by SPE in canine pyometra. The present study was thus aimed to identify changes in the serum protein profile to monitor inflammation in dogs with pyometra using serum protein electrophoresis (SPE), in addition to the analysis of the concentration of single acute phase proteins (APPs). By SPE analysis, decreased levels of albumin and elevated levels of α2-globulin and ß-globulin were noted in dogs with pyometra. In addition, the concentration of APPs, including the C-reactive protein (CRP), serum amyloid A (SAA), and haptoglobin (Hp), were also elevated in dogs with pyometra. The present study provides fundamental data for inflammatory indicators of canine pyometra.

Biophysical characteristics of dandruff-affected scalp categorized on the basis of sebum levels.

BACKGROUND: Various sebum levels can be detected in dandruff-affected scalps. However, few studies have compared the biophysical characteristics of dandruff scalps categorized based on sebum levels. AIMS: To investigate and compare the biophysical characteristics of dandruff-affected scalps categorized based on sebum levels. METHODS: Fifty-four Korean women with dandruff and 30 healthy Korean women underwent physiological measurements, including evaluation of sebum and hydration levels, pH, and transepidermal water loss (TEWL) in the scalp. The levels of the biomarkers of interleukin-8 (IL-8) and kallikrein 5 (KLK5) and corneodesmosomes were investigated in the stratum corneum (SC) of the scalp. RESULTS: Dandruff was categorized as dry (low-sebum, n = 25) or oily (high-sebum, n = 29) based on a sebum cutoff level of 97.82 µg/cm2 . Both dry and oily dandruff-affected scalps showed significantly decreased hydration levels and increased pH and TEWL compared with healthy subjects, with hydration levels being lower in dry dandruff-affected scalps. IL-8 expression was significantly increased in the oily dandruff-affected scalp. In addition, both dry and oily dandruff-affected scalps showed significantly increased KLK5 levels in the SC, with the levels being higher in oily dandruff-affected scalps. Altered distribution of corneodesmosomes, present on the entire surface area of the corneocytes, was notable in oily dandruff-affected scalps. CONCLUSION: The biophysical characteristics of the two types of dandruff represent the influence of different characteristics, including hydration levels, expression of IL-8 and KLK5, and corneodesmosome distribution. Thus, strategies to reduce dandruff levels should differ according to sebum levels.

Supplementation with eicosapentaenoic acid and linoleic acid increases the production of epidermal ceramides in in vitro canine keratinocytes.

BACKGROUND: Few studies have investigated the effects of essential fatty acids on the production of epidermal ceramide (CER) in canine keratinocytes. HYPOTHESIS/OBJECTIVES: To investigate the effects of eicosapentaenoic acid (EPA) and linoleic acid (LA) supplementation on the production of CERs using an in vitro canine keratinocyte culture system. METHODS AND MATERIALS: Canine keratinocyte cells (MSCEK) were incubated with high Ca2+ [1.8 mM calcium chloride (CaCl2 )] serum-free medium, supplemented with 3 µM EPA and 15 µM LA when the cells showed confluency. On Day 8 of application, lipid analysis using high-performance thin layer chromatography and real-time PCR for detecting glucosylceramide synthase and ceramidase were performed. RESULTS: It was revealed that the amounts of CER (EOS) (combination of ω-hydroxy fatty acids and sphingosines), CER [EOP] (combination of ω-hydroxy fatty acids and phytosphingosines) and a mixture of CER [NS] (combination of nonhydroxy fatty acids and sphingosines) and [NDS] (combination of nonhydroxy fatty acids and dihydrosphingosines), as well as total CERs, were significantly increased in cells incubated with EPA and LA compared to those of the vehicle, with increased mRNA expression of glucosylceramide synthase. CONCLUSIONS AND CLINICAL IMPORTANCE: These findings suggest that EPA and LA can potentially alter the CER profile of the skin and this may contribute to its epidermal barrier function in canine skin.

Alterations in serum protein electrophoresis profiles during the acute phase response in dogs with acute pancreatitis.

The quantification of serum proteins is a useful tool for diagnosing and monitoring various diseases that involve changes in the concentrations of these proteins. As canine acute pancreatitis (AP) accompanies the systemic inflammatory response syndrome, serum proteins such as C-reactive protein (CRP) have been used as inflammatory markers for dogs with AP. The goal of this study was to investigate the overall profiles of serum proteins by serum protein electrophoresis (SPE) and to determine the concentration of acute phase proteins (APPs) in dogs with AP in order to better understand serum protein profiles as diagnostic markers in these dogs. Decreased levels of albumin and increased levels of alpha-2 globulin were observed in dogs with AP by SPE. Among APPs, elevated concentrations of CRP, serum amyloid A (SAA), and haptoglobin were detected. The concentration of SAA was positively correlated with that of CRP, which suggests that SAA could be a sensitive marker of inflammation in dogs with AP, similar to CRP.

La quantification des protéines sériques est un outil utile pour diagnostiquer et suivre différentes pathologies qui impliquent des changements dans les concentrations de ces protéines. Comme la pancréatite aiguë (AP) accompagne le syndrome de réponse inflammatoire systémique, les protéines sériques telles que la protéine C-réactive (CRP) ont été utilisées comme marqueurs d'inflammation chez les chiens avec AP. L'objectif de la présente étude était d'examiner les profils globaux des protéines sériques par électrophorèse des protéines sériques (SPE) et de déterminer les concentrations des protéines de phase aiguë (APPs) chez les chiens avec AP afin de mieux comprendre les profils de protéines sériques comme marqueurs diagnostiques chez ces chiens. Des niveaux diminués d'albumine et des niveaux augmentés de globuline alpha-2 furent observés par SPE chez des chiens avec AP. Parmi les APPs, des concentrations élevées de CRP, d'amyloïde sérique A (SAA), et d'haptoglobine furent détectées. La concentration de SAA était corrélée positivement avec celle de CRP, ce qui suggère que SAA pourrait être un marqueur sensible d'inflammation chez les chiens avec AP, de manière similaire à la CRP.(Traduit par Docteur Serge Messier).

Priming mobilization of hair follicle stem cells triggers permanent loss of regeneration after alkylating chemotherapy.

The maintenance of genetic integrity is critical for stem cells to ensure homeostasis and regeneration. Little is known about how adult stem cells respond to irreversible DNA damage, resulting in loss of regeneration in humans. Here, we establish a permanent regeneration loss model using cycling human hair follicles treated with alkylating agents: busulfan followed by cyclophosphamide. We uncover the underlying mechanisms by which hair follicle stem cells (HFSCs) lose their pool. In contrast to immediate destructive changes in rapidly proliferating hair matrix cells, quiescent HFSCs show unexpected massive proliferation after busulfan and then undergo large-scale apoptosis following cyclophosphamide. HFSC proliferation is activated through PI3K/Akt pathway, and depletion is driven by p53/p38-induced cell death. RNA-seq analysis shows that HFSCs experience mitotic catastrophe with G2/M checkpoint activation. Our findings indicate that priming mobilization causes stem cells to lose their resistance to DNA damage, resulting in permanent loss of regeneration after alkylating chemotherapy.

UVB-induced depletion of donor-derived dendritic cells prevents allograft rejection of immune-privileged hair follicles in humanized mice.

Dendritic cells (DCs) are key targets for immunity and tolerance induction; they present donor antigens to recipient T cells by donor- and recipient-derived pathways. Donor-derived DCs, which are critical during the acute posttransplant period, can be depleted in graft tissue by forced migration via ultraviolet B light (UVB) irradiation. Here, we investigated the tolerogenic potential of donor-derived DC depletion through in vivo and ex vivo UVB preirradiation (UV) combined with the injection of anti-CD154 antibody (Ab) into recipients in an MHC-mismatched hair follicle (HF) allograft model in humanized mice. Surprisingly, human HF allografts achieved long-term survival with newly growing pigmented hair shafts in both Ab-treated groups (Ab-only and UV plus Ab) and in the UV-only group, whereas the control mice rejected all HF allografts with no hair regrowth. Perifollicular human CD3+ T cell and MHC class II+ cell infiltration was significantly diminished in the presence of UV and/or Ab treatment. HF allografts in the UV-only group showed stable maintenance of the immune privilege in the HF epithelium without evidence of antigen-specific T cell tolerance, which is likely promoted by normal HFs in vivo. This immunomodulatory strategy targeting the donor tissue exhibited novel biological relevance for clinical allogeneic transplantation without generalized immunosuppression.

Nonpigmented hair removal using photodynamic therapy in animal model.

BACKGROUND AND OBJECTIVE: Lasers have been successfully used for decades to remove dark hair. However, laser removal of nonpigmented hair is challenging due to the lack of chromophores. The aim of this study was to use photodynamic therapy (PDT) to remove nonpigmented hair. STUDY DESIGN/MATERIAL AND METHODS: We compared the efficacy of permanent hair reduction in white BALB/c and black C57BL/6 mice treated with PDT or an 800-nm diode laser. We collected skin biopsy specimens and investigated post-PDT histologic changes and molecular changes. RESULTS: We observed keratin 15 staining in the bulge area and alkaline phosphatase staining in the dermal papilla following PDT. We observed a temporary, catagen-like transformation in nonpigmented hair follicles after PDT. We observed apoptotic cells in the hair matrix after PDT. Irradiation with an 800-nm diode laser did not achieve nonpigmented hair removal. Multiple PDT sessions achieved permanent reduction of nonpigmented hair. Interestingly, removal of black hair using PDT was less efficient. CONCLUSION: Our results suggest that PDT can damage the nonpigmented hair matrix, but not stem cells or dermal papillae. Repeated PDT may impair the hair-regeneration capacity via a bystander effect on bulge stem cells or dermal papillae. In this study, we found it was possible to remove nonpigmented hair using PDT. Lasers Surg. Med. 48:748-762, 2016. © 2016 Wiley Periodicals, Inc.

Development of a Model for Chemotherapy-Induced Alopecia: Profiling of Histological Changes in Human Hair Follicles after Chemotherapy.

Optimized research models are required to further understand the pathogenesis and prophylaxis of chemotherapy-induced alopecia. Our aim was to develop a mouse model for chemotherapy-induced alopecia by follicular unit transplantation of human hair follicles onto immunodeficient mice. Twenty-two weeks after transplantation, a single dose of cyclophosphamide (Cph) was administered to mice in the Cph100 (100 mg/kg) and Cph150 (150 mg/kg) groups. On day 6, hair follicles showed dystrophic changes, with swollen dermal papilla and ectopic melanin clumping in the hair bulb. In addition, upregulated expression of apoptotic regulators [P53, Fas/Fas-ligand, tumor necrosis factor-related apoptosis-inducing ligand/tumor necrosis factor-related apoptosis-inducing ligand receptor (TRAIL/TRAIL receptor), and Bax], increased apoptotic matrix keratinocytes, downregulated Ki67 expression, and decreased melanogenic protein in the hair bulb were noted in both groups. After 12 treatment days, hair follicles in Cph100 mice appeared to diminish dystrophic changes. In contrast, hair follicles of Cph150 mice prematurely entered a dystrophic catagen phase after 9 treatment days, and immunofluorescence staining for Ki67 and melanogenic protein expressions was barely visible. Two hair follicle damage response pathways were observed in this model, namely dystrophic anagen (Cph100) and catagen (Cph150) pathways. Our model might be useful for further understanding the impact of chemotherapy on human hair follicles.

A role of placental growth factor in hair growth.

BACKGROUND: The dermal papilla (DP) comprises specialized mesenchymal cells at the bottom of the hair follicle and plays a pivotal role in hair formation, anagen induction and the hair cycle. In this study, DPs were isolated from human hair follicles and serially subcultured. From each subculture at passages 1, 3, and 5 (n=4), we compared gene expression profiles using mRNA sequencing. Among the growth factors that were down-regulated in later passages of human DP cells (hDPCs), placental growth factor (PlGF) was selected. OBJECTIVE: To elucidate the effect of PlGF on hair growth. METHODS: We evaluated the effect of PlGF on hDPCs and on ex vivo hair organ culture. We investigated the effect of PlGF on an in vivo model of depilation-induced hair regeneration. RESULTS: We confirmed that the mRNA and protein expression levels of PlGF significantly decreased following subculture of the cells. It was shown that PlGF enhanced hair shaft elongation in ex vivo hair organ culture. Furthermore, PlGF significantly accelerated hair follicle growth and markedly prolonged anagen hair growth in an in vivo model of depilation-induced hair regeneration. PlGF prevented cell death by increasing the levels of phosphorylated extracellular signal-regulated kinase (ERK) and cyclin D1 and promoted survival by up-regulation of phosphorylated Akt and Bcl2, as determined by Western blotting. CONCLUSION: Our results suggest that PlGF plays a role in the promotion of hair growth and therefore may serve as an additional therapeutic target for the treatment of alopecia.

Pretreatment of epidermal growth factor promotes primary hair recovery via the dystrophic anagen pathway after chemotherapy-induced alopecia.

Epidermal growth factor (EGF) is not only a cell growth stimulant but also has a catagen-inducing effect. Because chemotherapeutic agents primarily damage anagen hair follicles, it would be important to investigate whether catagen inducers have beneficial effects in chemotherapy-induced alopecia (CIA). We pretreated hair follicles with topical EGF-liposomal solution in the C57BL/6 mouse model of cyclophosphamide-induced alopecia and observed the catagen-inducing property and damage response pathway after CIA. We confirmed that topical EGF application induced a catagen-like stage and found that these catagen-like hairs were protected from chemotherapy-mediated damage. Moreover, our results showed that EGF treatment favoured primary hair recovery via the dystrophic anagen pathway after CIA. Given that hair follicles subjected to less severe chemotherapeutic insult enter the dystrophic anagen pathway followed by primary recovery, the results of this study suggest that catagen inducers could be useful as a new alopecia-protection strategy, especially in the context of CIA.

The stratum corneum: the rampart of the mammalian body.

BACKGROUND: The stratum corneum (SC) is the outermost region of the epidermis and plays key roles in cutaneous barrier function in mammals. The SC is composed of 'bricks', represented by flattened, protein-enriched corneocytes, and 'mortar', represented by intercellular lipid-enriched layers. As a result of this 'bricks and mortar' structure, the SC can be considered as a 'rampart' that encloses water and solutes essential for physiological homeostasis and that protects mammals from physical, chemical and biological assaults. STRUCTURES AND FUNCTIONS: The corneocyte cytoskeleton contains tight bundles of keratin intermediate filaments aggregated with filaggrin monomers, which are subsequently degraded into natural moisturizing compounds by various proteases, including caspase 14. A cornified cell envelope is formed on the inner surface of the corneocyte plasma membrane by transglutaminase-catalysed cross-linking of involucrin and loricrin. Ceramides form a lipid envelope by covalently binding to the cornified cell envelope, and extracellular lamellar lipids play an important role in permeability barrier function. Corneodesmosomes are the main adhesive structures in the SC and are degraded by certain serine proteases, such as kallikreins, during desquamation. CLINICAL RELEVANCE: The roles of the different SC components, including the structural proteins in corneocytes, extracellular lipids and some proteins associated with lipid metabolism, have been investigated in genetically engineered mice and in naturally occurring hereditary skin diseases, such as ichthyosis, ichthyosis syndrome and atopic dermatitis in humans, cattle and dogs.

Epidermal structure created by canine hair follicle keratinocytes enriched with bulge cells in a three-dimensional skin equivalent model in vitro: implications for regenerative therapy of canine epidermis.

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.

Skin lipid profiling in normal and seborrhoeic shih tzu dogs.

BACKGROUND: Seborrhoea is a clinical condition resulting in excessive lipid and/or scale on the skin and is a common and important skin disease of dogs. However, there is little information on the skin surface lipid composition of dogs with seborrhoea. HYPOTHESIS/OBJECTIVES: To compare skin surface lipid profiles in normal and seborrhoeic shih tzu dogs. METHODS: Fourteen client-owned dogs (seven seborrhoeic and seven normal) were investigated. Lipids in sebaceous glands (SGs) were extracted from homogenized tissues of SG hyperplasia. Surface lipid was collected by tape stripping [stratum corneum (SC)-enriched fraction] and acetone-wetted cotton swab (acetone-extracted fraction). Lipids in SGs, SC-enriched fractions and acetone-extracted fractions were evaluated by high-performance thin-layer chromatography. RESULTS: Lipids in SGs mainly consisted of cholesterol esters, wax esters and triglycerides, whereas lipids in the SC-enriched fraction mainly consisted of ceramides. The acetone-extracted fraction contained a mixture of lipid classes recognized in SG- and SC-enriched fractions. In seborrhoeic dogs, concentrations of wax esters and triglycerides in the acetone-extracted fraction were significantly higher than in control dogs (P = 0.0285). Amounts of total ceramides (in micrograms) per milligram of SC were not significantly different between the two groups (P = 0.5204). Interestingly, two unknown ceramide fractions, which accounted for 20% of the total ceramides, were recognized exclusively in seborrhoeic dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: These results provide evidence that the skin surface lipid profiles are altered in shih tzu dogs with seborrhoea.

Alteration of stratum corneum ceramide profiles in spontaneous canine model of atopic dermatitis.

Ceramides (CERs) in the stratum corneum (SC) are thought to play a key role in cutaneous barrier function. It has been reported that human SC contains 11 free CER classes and that their profiles are altered in humans with atopic dermatitis (AD). Although decreased proportions of free CERs or quantities of protein-bound CERs in the SC have been reported in dogs with AD, the overall profile of CERs in the canine SC has not been fully elucidated. The aim of this study was thus to investigate the profile of free CERs in the canine SC and to identify alterations in the CER profiles in dogs with AD. Normal-phase liquid chromatography-electrospray ionization-mass spectrometry indicated 11 clusters of peaks for free CER classes, similar to those recognized in the human SC. The fractions of free SC CER in dogs with AD and in breed- and age-matched healthy dogs were quantitatively compared using high-performance thin-layer chromatography. CER[EOS], CER[EOP] and CER[NP], which are known to be decreased in the skin of humans with AD, were also decreased in the skin of dogs with AD. These findings highlight canine AD as a spontaneous animal model for investigating the disruption of CER-associated cutaneous barrier functions in the corresponding human disease.