Ursolic Acid Induces Beneficial Changes in Skeletal Muscle mRNA Expression and Increases Exercise Participation and Performance in Dogs with Age-Related Muscle Atrophy

Muscle atrophy and weakness are prevalent and debilitating conditions in dogs that cannot be reliably prevented or treated by current approaches. In non-canine species, the natural dietary compound ursolic acid inhibits molecular mechanisms of muscle atrophy, leading to improvements in muscle health. To begin to translate ursolic acid to canine health, we developed a novel ursolic acid dietary supplement for dogs and confirmed its safety and tolerability in dogs. We then conducted a randomized, placebo-controlled, proof-of-concept efficacy study in older beagles with age-related muscle atrophy, also known as sarcopenia. Animals received placebo or ursolic acid dietary supplements once a day for 60 days. To assess the study's primary outcome, we biopsied the quadriceps muscle and quantified atrophy-associated mRNA expression. Additionally, to determine whether the molecular effects of ursolic acid might have functional correlates consistent with improvements in muscle health, we assessed secondary outcomes of exercise participation and T-maze performance. Importantly, in canine skeletal muscle, ursolic acid inhibited numerous mRNA expression changes that are known to promote muscle atrophy and weakness. Furthermore, ursolic acid significantly improved exercise participation and T-maze performance. These findings identify ursolic acid as a natural dietary compound that inhibits molecular mechanisms of muscle atrophy and improves functional performance in dogs.

Effect of l-theanine tablets in reducing stress-related emotional signs in cats: an open-label field study

Background

L-theanine is an aminoacid found in tea leaves which has relaxing effects in humans and animals. It is a structural analogue of glutamate which can bind glutamate receptors. Although the relaxing action of L-theanine has been shown in humans, laboratory animals and dogs, it has never been published in cats. The goal of this open-label, multicentre and prospective trial was to determine whether an L-theanine based oral supplement (Anxitane®, Virbac, France) could attenuate manifestations of stress in cats under field conditions.

Case presentation

Thirty-three privately owned cats presenting signs associated with stress or fear (inappropriate urination/defecation, fear-induced aggressiveness, hypervigilance/tenseness or physical/functional manifestations of stress) for at least 1 month, were included in the study. They were given L-theanine (Anxitane®, 25 mg twice a day) for 30 days and 20 stress-related parameters were scored at Days 0, 15 and 30. The evolution of some parameters was also rated relative to Day 0. All median scores of the 20 parameters were significantly reduced at D30, and 30/33 cats (91%) had a reduced global score at the end of the study, including 21/33 with ≥50% score reduction. The median (IQR) global scores went from 18 (13-23) at D0 to 11 (8-13) at D15 and 5 (3-12) at D30 (p < 0.0001; Friedman test; significant reduction starting from D15). All the stress-related signs were significantly improved compared to D0, according to the owners, especially inappropriate elimination. Tablet palatability was judged good or very good in 94% of cases with spontaneous intake by cats when given by hand or in food. Tolerance was satisfactory as well, and no side effects were reported, so that most owners (27/33; 82%) were satisfied with the product.

Conclusions

Despite the lack of a placebo group, it can be concluded that L-theanine (Anxitane®) helped to improve the undesirable manifestations of stress in cats in as soon as 15 days, though better results could be seen after 30 days of administration. These encouraging results show that L-theanine can help manage stress-related behaviour, but additional trials with a placebo group should be run to confirm this effect.

The use of recombinant omega interferon therapy in canine atopic dermatitis: a double-blind controlled study

This double-blind controlled study assessed whether reduced doses of omega interferon (rFeIFN-omega) (Virbagen Omega) could improve the clinical signs of canine atopic dermatitis (CAD) over a 6-month period, in comparison with cyclosporin. Thirty-one dogs diagnosed with CAD were entered in the study. Complicating infections were treated prior to entry. Dogs received 10 injections of rFeIFN-omega (1-5 million units according to bodyweight) or placebo over 6 months, and placebo capsules or cyclosporin (5 mg/kg) once daily for 2 months and then twice weekly for 4 months in groups 1 and 2 respectively. Flea control, non-medicated shampooing and ear cleansing were performed regularly. If a bacterial infection or Malassezia overgrowth developed, it was treated with oral cephalexin or with 3% chlorhexidine shampoo respectively. Oral prednisolone was used before day 90 to relieve pruritus when required for humane reasons (1 mg/kg once daily for 7 days). The CADESI-03 and a pruritus index were evaluated on day (D) 0, D14, D35, D56, D90, D120 and D180. No significant difference was detected between the groups for the time courses of lesions or pruritus over 6 months. On D90, the proportions of dogs with > or =50% improvement of pruritus and lesion scores were 56% and 72% respectively with interferon, 75% and 75% respectively with cyclosporin. Five dogs from group 1 and two dogs from group 2 were withdrawn from the study for treatment failure. Both products were well tolerated. Treatment with rfeIFN-omega at low doses may help for the long-term management of CAD.

Monosaccharide inhibition of adherence by Pseudomonas aeruginosa to canine corneocytes

The effect of D-galactose, D-mannose, L-rhamnose and dextrose on the adhesion to canine corneocytes by three strains of Pseudomonas aeruginosa was studied in six healthy dogs. Canine corneocytes were collected from the inner aspect of the pinna using adhesive discs (D-Squame). Half millimetre of bacterial suspension in phosphate-buffered saline (PBS) with or without the addition of a monosaccharide was placed over the corneocyte layer and incubated in moist chambers. Image analysis was used to quantify bacterial adherence to corneocytes. The three strains of Pseudomonas adhered well to canine corneocytes. All monosaccharides tested inhibited the adherence of Pseudomonas to canine corneocytes. The mean reduction in adhesion for individual sugars at a concentration of 0.1% was 40.2% (dextrose), 30.8% (L-rhamnose), 25.6% (D-galactose) and 19.4% (D-mannose). When D-galactose, D-mannose and L-rhamnose were used in combination at 0.1% concentration, the mean reduction in adherence was 52.9%. The monosaccharides studied may have a potential role in the management of Pseudomonas infections in dogs.

Effects of a topically applied preparation of epidermal lipids on the stratum corneum barrier of atopic dogs

Canine atopic dermatitis (AD) is characterized ultrastructurally by disorganization of the lamellar lipids (LLs) in the stratum corneum (SC), similar to that seen in the human disease. This study, based on the examination of biopsy samples, was designed to investigate the expression of canine epidermal lipids and to evaluate quantitatively, by means of electron microscopy and ruthenium tetroxide post-fixation, the effect of a new topical skin lipid complex (SLC) on the structural deficit in the skin of five dogs with AD. The non-lesional skin of atopic dogs differed from the skin of healthy dogs in that the LLs were reduced in number and highly disorganized. After repeated applications of SLC to the non-lesional skin of dogs with AD, numerous LLs were observed in the deepest part of the SC, occupying 74% of the inter-corneocyte space, while they accounted for only 31.8% of the inter-corneocyte space in comparable biopsy samples from untreated (control) skin of the same dogs. In contrast, the LLs filled 89.5% of the deepest inter-corneocyte spaces in the SC of healthy dogs. Many keratinosomes were observed at the interface between living epidermis and SC after treatment of non-lesional AD skin. Stacks of short LL discs represented 57.6% of the total LLs found in the newly formed SC compactum in the treated atopic dogs. It is suggested that the treatment with SLC stimulated the production and secretion of endogenous SC lipids, contributing to the formation of an improved epidermal barrier.

Effect of S-adenosylmethionine tablets on the reduction of age-related mental decline in dogs: a double-blinded, placebo-controlled trial

Oral S-adenosylmethionine (SAMe) tosylate supplementation (Novifit tablets, Virbac) was evaluated as a dietary aid for the management of age-related mental impairment in dogs. Thirty-six dogs older than 8 years that had displayed signs of cognitive dysfunction for at least 1 month were selected for the study. The dogs were administered 18 mg/kg SAMe tosylate (n=17) or identical placebo tablets (n=19) for 2 months. Concurrent behavioral treatment was forbidden. A 14-item standardized questionnaire evaluated behavior and locomotion difficulties. Compared with the placebo group, SAMe-treated dogs showed greater improvement in activity (41.7% versus 2.6% after 4 weeks, P<.0003; 57.1% versus 9.0% after 8 weeks, P<.003) and awareness (33.3% versus 17.9% after 4 weeks, P<.05; 59.5% versus 21.4% after 8 weeks, P<.01). The aggregate mental impairment score was reduced by more than 50% in 41.2% and 15.8% of dogs treated with SAMe and placebo, respectively, at week 8. SAMe tosylate tablets proved safe and effective in improving signs of age-related mental decline in dogs.

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.

The efficacy of an antiseptic and microbial anti-adhesive ear cleanser in dogs with otitis externa

A new antimicrobial ear cleanser was evaluated for the treatment of bacterial and yeast ear infection in dogs. Forty-five dogs with erythemato-ceruminous or purulent otitis externa were randomly allocated to two treatment groups: reference ear cleanser (Epiotic, Virbac) or test ear cleanser (Epiotic Advanced, Virbac). Ear cleansing was performed twice daily for 2 weeks, and no other treatment was allowed. By week 2, clinical (exudate quantity, erythema, stenosis, excoriation, and odor) and discomfort (pain, ear scratching, and head shaking) scores were significantly decreased (P < .0001 for all) and no microbial overgrowth could be detected in 25 (64.1%) and 32 (68.1%) ears treated with Epiotic and Epiotic Advanced, respectively. The new pH-balanced, propylene glycol-free test ear cleanser, which incorporates microbial adhesin-blocking carbohydrates, proved as effective as the reference acidic formula.