Evaluation on the effects of 0.1% Peumus boldus leaf and Spiraea ulmaria plant extract combination on bacterial colonization in canine atopic dermatitis: A preliminary randomized, placebo controlled, double-blinded study.

Defective skin barrier characterize canine atopic dermatitis (AD). Pyoderma is the most common complication. Herbal compounds have been suggested as alternatives to control bacterial colonization for their effect on natural antimicrobial peptides (AMPs). This study evaluated the effects of 0.1% Peumus boldus leaf and Spiraea ulmaria plant extract combination on clinical signs, bacterial colonization and AMPs secretion in atopic dogs compared to placebo. Twenty privately-owned atopic dogs were randomly divided in 2 groups (treatment: n = 10; placebo: n = 10) and their abdomen was sprayed every 24 h for 4 weeks. Total and inguinal clinical scores (CADESI-03), manual bacterial count, and skin washes for AMPs (cBD3-like and cCath) were performed on days 0, 14 and 28. AMPs were detected using in-house, previously-validated, canine-specific ELISAs. Data were statistically analyzed and a p < 0.05 was considered significant. Clinical scores and AMPs secretion did not differ significantly between the two groups at any time point. A significant reduction of the clinical scores was seen in the placebo group at 14 and 28 days (p < 0.04). On days 14 and 28, a reduction in the bacterial count was seen in the treated group compared with placebo (p < 0.009 and p = 0.04, respectively). Compared to baseline, a reduction in Staphylococcus spp. was seen in the treated group after 14 days of treatment (p < 0.03). These results show the efficacy of this plant extract combination against bacterial colonization, suggesting its potential usefulness in preventing bacterial infection in atopic dogs. The influence of this compound on AMPs secretion or other mechanisms should be further evaluated.

Evaluation of the in vitro effect of Boldo and Meadowsweet plant extracts on the expression of antimicrobial peptides and inflammatory markers in canine keratinocytes.

Dogs with allergies are prone to skin infections and treatments/preventatives to boost innate immune-defenses are beneficial. The aim of this study was to evaluate the effects of Boldo and Meadowsweet extracts on the expression of ß-defensins (cBD), cathelicidin (cCath), and pro-inflammatory cytokines in canine keratinocyte. This study had two phases. Phase I evaluated mRNA expression of cBD103 and cCath, and secretion of cCath, IL-8 and TNF-α by keratinocytes harvested from healthy (n=5) and atopic (n=5) age-matched beagles exposed to Boldo (2% to 0.2%) and Meadowsweet (1% to 0.2%) extracts. Phase II focused on atopic keratinocytes (n=14) exposed to 0.2% Boldo, 0.2% Meadowsweet, and a mixture of 0.1% of both extracts. Phase I: cBD103 mRNA (all concentrations) and TNF-α secretion (2% Boldo) were increased in atopic compared with healthy keratinocytes. In atopic keratinocytes, cBD103 was increased after exposure to 1.5% and 0.2% Boldo. In healthy keratinocytes, 1% and 0.2% Meadowsweet, and 2% Boldo increased and decreased IL-8 secretion, respectively. In atopic keratinocytes, IL-8 increased after exposure to 1% and 0.4% Meadowsweet extract. Phase II: cBD103 mRNA increased after exposure to 0.2% Meadowsweet and to 0.1% mixture. cCath was increased after 0.2% Boldo, but decreased after 0.2% Meadowsweet or the 0.1% mixture. TNF-α secretion was decreased after 0.2% Boldo. It is concluded that low concentrations of both extracts and their combination may have some effects on cCath and cBD103 without stimulating an inflammatory response. However, more studies are needed to clarify the effects of these extracts on the local immunity.

Comparative palatability of five supplements designed for cats suffering from chronic renal disease.

BACKGROUND: Intestinal phosphate binders, uremic toxin binders and some other types of supplements are an integral part of the management of chronic kidney disease (CKD) in various species, including cats. This pathology in domestic carnivores requires life-long nutritional and medical management. In this context, the compliance of owners and patients cannot be achieved without an adequate level of palatability for oral medication or supplementation. Knowing that hyporexia and anorexia are among the most commonly seen clinical signs in cats suffering from CKD this is already, in itself, a serious obstacle to acceptable compliance in sick animals. The aim of the present study was to investigate the palatability of four commercially available products designed for cats suffering from CKD: Ipakitine® (Vetoquinol, France), Azodyl® (Vetoquinol, USA), Renalzin® (Bayer, France), Rubenal® (Vetoquinol, France) and an additional recently developed product: Pronefra® (Virbac, France). The study was performed with a group of previously-characterised cats, all living in an enriched and well-being securing environment of an independent centre housing panels of pets expert in palatability measurement. In total 172 monadic testings were performed. The palatability of each product was assessed by measuring their rates of prehension and consumption, and the consumption proportions were also analysed. RESULTS: The most palatable presentation (based on useful consumption) was Pronefra®, which was significantly higher than Azodyl® (p = 0.046), Ipakitine® (p < 0.0001), Renalzin® (p < 0.0001) and Rubenal® (p < 0.0001). The product with the highest rate of prehension was also Pronefra®, which was significantly higher than Azodyl® (p = 0.0019), Ipakitine® (p = 0.0023), Renalzin® (p = 0.0008) and Rubenal® (p < 0.0001). CONCLUSION: Pronefra® was the most palatable presentation tested, meaning it may be useful for improving ease of supplementation in CKD cats.

The natural antioxidants, pomegranate extract and soy isoflavones, favourably modulate canine endothelial cell function.

Cardiovascular disease, preceded by vascular endothelial dysfunction, is a prominent cause of death in dogs. L-carnitine and taurine, well known for their antioxidative capacity, beneficially affect cardiovascular disease as well as certain dog cardiomyopathies. It is well established that vascular endothelial dysfunction precedes cardiovascular disease and that "vasoprotective factors" (NO and antioxidants) prevent apoptosis, whereas "risk factors" such as oxidized LDL, hyperglycemia, and free fatty acids trigger it in cultured human vascular endothelial cells. Whereas human vascular cell in vitro models are widely established and used for the characterisation of potential vasoprotective substances, such models are not available for canine endothelial cells. In the present study we therefore developed an in vitro model, which allows the testing of the effects of different substances on proliferation and apoptosis in canine aortic endothelial cells. This model was used to test L-carnitine, taurine, pomegranate extract, and Soy Isoflavones in comparison to reference substances (glutathione and pioglitazone) previously shown to modulate human endothelial cell function. L-carnitine and taurine neither exhibited antiproliferative nor antiapoptotic activities in the context of this study. However extracts from pomegranate and soy isoflavones dramatically reduced proliferation and apoptosis in a dose dependent fashion, being in line with a vasoprotective activity in dogs.

Spot-on skin lipid complex as an adjunct therapy in dogs with atopic dermatitis: an open pilot study.

The purpose of this paper was to evaluate the efficacy of topical skin lipid complex (SLC) in canine atopic dermatitis (AD). Eight dogs with chronic AD and no improvement of main therapy in symptoms, erythema, lichenification, excoriation, and alopecia in the previous month were treated with SLC topically as adjunct therapy at lesion sites twice weekly for 12 weeks. A statistically significant reduction (26.0%, P < 0.05) in the third version of the Canine Atopic Dermatitis Extent and Severity Index (CADESI-03) modification from baseline was recorded 6 weeks after treatment, with marked reduction in the erythema subscore (36.2%, P < 0.005). A significant reduction in excoriation and alopecia subscores was observed 6 weeks after treatment (39.9%, P < 0.05 and 19.9%, P < 0.05, resp.). However, the lichenification subscore was not reduced significantly at 6 or 12 weeks. These findings suggest that topical SLC may have therapeutic and clinical benefits in dogs with AD.

Analysis of epidermal lipids in normal and atopic dogs, before and after administration of an oral omega-6/omega-3 fatty acid feed supplement. A pilot study.

Alterations of the lipid expression in the skin of human and canine atopic subjects may be one of the key factors in the disease development. We have analyzed the ultrastructure of the clinically uninvolved skin of atopic dogs and compared it with the lipid composition of their tape-stripped stratum corneum (SC). The effect of a 2 month treatment of atopic dogs by food supplementation with a mixture of essential fatty acids was evaluated on skin samples taken before and after the treatment period. Electron microscopy revealed that the non-lesional skin of atopic dogs exhibited an abnormal and largely incomplete structure of the lamellar lipids with little cohesion between the corneocyte strata. The SC of atopic dogs was characterized by a significant decrease in the lipid content when compared to the healthy controls. Following oral supplementation with the mixture of essential fatty acids, the overall lipid content of the SC markedly increased. This feature was observed both with the free and, most importantly, with the protein-bound lipids (cholesterol, fatty acids and ceramides), the latter constituting the corneocyte-bound scaffold for ordinate organisation of the extracellular lipid bi-layers. Indeed, the semi-quantitative electron microscopy study revealed that the treatment resulted in a significantly improved organization of the lamellar lipids in the lower SC, comparable to that of the healthy dogs. Our results indicate the potential interest of long-term alimentary supplementation with omega-6 and omega-3 essential fatty acids in canine atopic dermatitis.

Atopic dermatitis in dogs is associated with a high heterogeneity in the distribution of protein-bound lipids within the stratum corneum.

The stratum corneum (SC) was taken from five atopic dogs by tape stripping (12 strips) of non-lesional areas of the abdomen. The free and protein-bound lipids were extracted and analyzed by thin-layer chromatography after fractionation on aminopropyl-bonded silica gel columns. A very frequent feature was the heterogeneity in the lipid content of consecutive layers. This was even more accentuated for the covalently bound lipids, with variations from one layer to another in the concentrations of cholesterol, omega hydroxylated ceramides and omega hydroxylated long-chain fatty acids. Among the free lipids, large amounts of glucosylceramides were present in canine atopic SC although they are nearly absent from the SC of normal dogs. A heterogeneous distribution of lipids was seen in canine atopic SC. These results suggest that strikingly deep variations occur in the lipid metabolism of keratinocytes in the skin of atopic dogs. In order to gain insight into this phenomenon, further studies should be focused on the activity of enzymes involved in both biosynthetic and catabolic processes.

Analysis of free and protein-bound ceramides by tape stripping of stratum corneum from dogs.

The free and protein-bound ceramides of dog stratum corneum (SC) were analyzed by thin-layer chromatography after tape stripping of the abdomen of five dogs. The sphingoid bases were identified by gas-liquid chromatography as sphingosine, phytosphingosine, and 6-hydroxysphingosine. Electrospray ionization-ion trap mass spectrometry was used to characterize the protein-bound ceramides containing sphingosine and omega-hydroxy long-chain fatty acids. Although the molecular species were the same ones in all dogs, wide quantitative variations in the patterns of SC ceramides were observed in different breeds of dogs. The free ceramide concentration changed with the depth of SC, with a higher concentration in the deep layers, whereas the concentration of protein-bound ceramides remained constant. These results show that canine SC is close to that of humans with respect to ceramides.

Role of sugars in surface microbe-host interactions and immune reaction modulation.

Sugars in the form of monosaccharides, oligosaccharides, polysaccharides and glycoconjugates (glycoproteins, glycolipids) are vital components of infecting microbes and host cells, and are involved in cell signalling associated with modulation of inflammation in all integumental structures. Indeed, sugars are the molecules most commonly involved in cell recognition and communication. In skin, they are essential to epidermal development and homeostasis. They play important roles in microbial adherence, colonization and biofilm formation, and in virulence. Two groups of pathogen recognition receptors, C-type lectins (CTL) and their receptors (CTLR), and the Toll-like receptors enable the host to recognize pathogen-associated molecular patterns (PAMPs), which are mainly glycolipids. The CTLs can recognize a wide variety of bacteria, fungi and parasites and are important in phagocytosis and endocytosis. TLRs are expressed on the surfaces of a variety of cells, including keratinocytes, dendritic cells, monocytes and macrophages; they play a major role in innate immunity. Interaction of TLRs with PAMPs initiates a cascade of events leading to production of reactive oxygen intermediates, cytokines and chemokines, and promotes inflammation. Exogenous sugars can block carbohydrate receptors and competitively displace bacteria from attachment to cells, including keratinocytes. Thus sugars may provide valuable adjunctive anti-inflammatory and/or antimicrobial treatment. A promising approach is the use of a panel of carbohydrate derivatives with anti-adhesive efficacy against bacteria frequently involved in diseases affecting skin and other epithelia. More complete characterization of sugar receptors and their ligands will provide further keys to use of carbohydrates in immunomodulation and infection control in skin.

Comparative effects of 2 antioxidants, selenomethionine and epigallocatechin-gallate, on catabolic and anabolic gene expression of articular chondrocytes.

OBJECTIVE: . To determine the effects of selenomethionine (Se-met) and epigallocatechin-gallate (EGCg) on gene expression, activation of mitogen-activating kinases, and DNA binding of nuclear factor-kappaB (NF-kappaB) and apolipoprotein-1 (AP-1) in articular chondrocytes. METHODS: Chondrocytes, cultured in low-oxygen tension, were pretreated with L-selenomethionine or EGCg for 24 h, followed by interleukin 1 (IL-1beta) for 1 h (nuclear and cytoplasmic extracts) or 24 h (RNA extraction). Reverse transcription-polymerase chain reaction was performed to determine mRNA levels of matrix metalloproteinases (MMP-1, -3, -13), aggrecanases (-1, -2), IL-1beta, inducible nitric oxide synthase, cyclooxygenases (-1, -2), type II collagen and aggrecan, and transforming growth factor-beta (TGF-beta1, -2, -3) and their receptors I and II. Activity of mitogen-activating protein kinases (MAPK) was assayed by Western blot and AP-1/NF-kB DNA binding by electrophoretic mobility shift assay. RESULTS: Pretreatment with 0.5 microM Se-met prevented IL-1beta-induced MMP-1 and aggrecanase-1 expression, and reduced the cytokine inhibitory effect on type II collagen, aggrecan core protein, and TGF-beta receptor II (TGF-betaRII) mRNA levels. EGCg was more efficient in modulating the effects of IL-1beta on the genes studied. Whereas EGCg inhibited the IL-1beta-activated MAPK, NF-kappaB, and AP-1, Se-met stimulated that signaling pathway. This could account for the differential effects exerted by these antioxidants on chondrocytes. CONCLUSION: Our data provide insights into the mechanisms whereby ECGg and selenium modulate chondrocyte metabolism. Despite their differential mechanisms of action, the 2 compounds may exert global beneficial effects on articular cartilage.