A pilot study on the effect of oclacitinib on epicutaneous sensitization and transepidermal water loss in a colony of atopic beagle dogs.

BACKGROUND: Dogs with atopic dermatitis are prone to sensitization to environmental allergens due to increased skin permeability; the effect of treatments on epicutaneous sensitizations is unknown. HYPOTHESIS/OBJECTIVES: To evaluate if oclacitinib (i) prevents new sensitizations and (ii) affects skin barrier function. ANIMALS: Atopic beagle dogs. METHODS: Aim 1. Ten dogs were randomly assigned to placebo or oclacitinib while exposed epicutaneously to a novel allergen. Sensitization was assessed using serum allergen-specific IgE and clinically by development of skin reactions at the site of allergen application. Time to develop dermatitis and allergen-specific IgE were compared between groups. Aim 2. Eight dogs were randomly assigned to placebo or oclacitinib for four weeks and challenged with an allergen known to trigger flares. After a four week wash-out, dogs were crossed-over and the protocol repeated. Transepidermal water loss (TEWL) was measured on days 0 and 28 of each arm. RESULTS: Aim 1. Oclacitinib significantly increased (P = 0.006) time to develop skin reactions compared to placebo. Four (of five) dogs receiving oclacitinib failed to develop skin reactions, whereas all placebo dogs developed dermatitis. There were no significant differences in allergen-specific IgE between groups. Aim 2. TEWL results were difficult to interpret. Significantly higher values were detected from the axilla in placebo compared to oclacitinib-treated dogs (P = 0.047). TEWL values were significantly higher from the inguinal area in oclacitinib (P = 0.039) treated dogs but not placebo at the end of the study. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinically, oclacitinib delayed development of dermatitis at the site of allergen application. TEWL results were difficult to interpret and additional studies are required for clarification.

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.

A randomized, double-blind, placebo-controlled study to evaluate the effect of EFF1001, an Actinidia arguta (hardy kiwi) preparation, on CADESI score and pruritus in dogs with mild to moderate atopic dermatitis.

Canine atopic dermatitis (AD) is common and new therapies are beneficial. This multicentric, randomized, double-blind, placebo-controlled study tested the efficacy of Actinidia arguta (hardy kiwi) (EFF1001) in dogs with mild/moderate AD. The study was divided into two stages. Stage 1 lasted 6 weeks. In the first 2 weeks prednisolone [days 1-3: 0.2 mg/kg twice daily (BID), days 4-14: 0.2 mg/kg every other day (EOD)] was administered. Responsive dogs were placed on prednisolone 0.2 mg/kg EOD + assigned test article [either placebo or EFF1001 (30 mg/kg)] once daily for 4 weeks. Stage 1 responders were advanced to stage 2, which involved 4 weeks of just EFF1001. Clinicians scored lesions using Canine Atopic Dermatitis Extent and Severity Index (CADESI) and owners scored pruritus using a Pruritus Visual Analogue Scale. Seventy-seven dogs were enrolled, 76 were randomized on day 14, and 57 (57/76 = 75%) completed stage 1 (27 in EFF1001 and 30 in placebo). At the end of stage 1, 35 of 57 dogs (35/57 = 61%) responded (18 in EFF1001 and 17 in placebo) and advanced to stage 2. At completion of stage 1, CADESI scores did not significantly differ between groups while pruritus decreased in EFF1001 group and approached significance. At completion of stage 2, 19 dogs (19/35 = 54%) responded (15/19 = 79% had received EFF1001 and 4/19 = 21% placebo in stage 1). After completing stage 2, dogs placed on EFF1001 throughout the study were 3.5 times more likely to either maintain or improve scores than those that started it in stage 2. It is concluded that EFF1001 is beneficial adjunctive therapy after prolonged use.

Evaluation of Lactobacillus rhamnosus strain GG for the prevention of atopic dermatitis in dogs.

OBJECTIVE: To evaluate the efficacy of the probiotic Lactobacillus rhamnosus strain GG for the alleviation or prevention of clinical signs of atopic dermatitis (AD) in genetically predisposed dogs. ANIMALS: 2 adult Beagles with severe AD and 16 puppies. PROCEDURES: The 2 adult Beagles were bred twice, with a year between breedings. Lactobacillus rhamnosus GG was administered to the bitch during the second pregnancy and to the puppies of the second litter from 3 weeks to 6 months of age. Both litters were epicutaneously sensitized to Dermatophagoides farinae. Blood samples were collected from puppies every 6 weeks to measure serum titers of allergen-specific IgE. At 6 months of age, all puppies underwent intradermal allergen testing and environmental challenge with D farinae. Clinical signs were scored. RESULTS: In the first litter, at 6 months of age, 7 of 7 puppies were strongly seropositive for IgE against D farinae, 6 had a positive reaction to intradermal testing, and 7 developed severe clinical signs of AD after the environmental challenge. In the second litter, 7 of 9 puppies were seropositive, 3 had a positive reaction to intradermal testing, and 6 developed dermatitis and pruritus after the challenge. The second litter had a significantly lower serum titer of allergen-specific IgE and milder reaction to intradermal testing, compared with the first litter. Clinical scores did not differ between litters. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of L rhamnosus GG to puppies appeared to reduce immunologic indicators of AD, although no significant decrease in clinical signs was detected.

The effects of capsaicin topical therapy in dogs with atopic dermatitis: a randomized, double-blinded, placebo-controlled, cross-over clinical trial.

The efficacy of twice daily topical application of capsaicin (0.025%) for the management of pruritus in dogs with atopic dermatitis (AD) was evaluated in double-blinded, placebo-controlled study. Twelve dogs with AD were randomly assigned to either 0.025% capsaicin or vehicle lotion applied twice daily for 6 weeks. After a 4-week wash-out period, treatments were switched. Significant improvement was reported by owners (P = 0.0006), but not by investigators. Owners noted temporary worsening of pruritus after the first week of capsaicin therapy. Overall capsaicin was well tolerated. Substance P (SP) concentrations in the skin did not correlate with the severity of the pruritus and did not change significantly over time and between treatments. Lesional skin had less SP than nonlesional skin (P = 0.03). These observations suggest that topical capsaicin should be further evaluated as an adjunctive antipruritic agent in dogs with AD.