1. Investigación

Myostatin is a growth factor related to muscular mass atrophy via mTOR pathway inhibition. Mutations in this gene have been correlated with high muscular mass development in different species of mammals, including human and dogs. Different studies have shown that sport practice increases myostatin gene expression. Some of them were conducted in canine breeds selected for different sport practices, including mushing sports. In this study, body weight, muscular mass, and serum levels of myostatin were analysed in different canine breeds, selected, and not selected for sprint and middle-distance racing, and the effect on epidemiological factors was evaluated. Sex, reproductive status, and canine breed affects body weight and muscular mass, being higher in males, and in sled canine breed. Age has an effect in body weight and myostatin serum levels, being lower in elder dogs. Sport practice and type of diet had an effect in muscular mass development but not in myostatin serum levels. Results showed a high positive correlation between muscular mass and body weight but not with myostatin levels. These results suggest that independent-myostatin mechanisms of mTOR pathway regulation could be related to muscular mass development in dogs.

Background The Ibizan Hound is a canine breed native to the Mediterranean region, where leishmaniasis is an endemic zoonosis. Several studies indicate a low prevalence of this disease in Ibizan Hound dogs, whereas other canine breeds present a high prevalence. However, the underlying molecular mechanisms still remain unknown. The aim of this work is to analyse the relationship between serum levels of cytokines and the genomic profiles in two canine breeds, Ibizan Hound (resistant canine breed model) and Boxer (susceptible canine breed model). Methods In this study, we analyse the haplotypes of genes encoding cytokines related to immune response of Leishmania infantum infection in twenty-four Boxers and twenty-eight Ibizan Hounds apparently healthy using CanineHD DNA Analysis BeadChip including 165,480 mapped positions. The haplo.glm extension of haplo.score was used to perform a General Linear Model (GLM) regression to estimate the magnitude of individual haplotype effects within each cytokine. Results Mean levels of interferon gamma (IFN-γ), interleukin 2 (IL-2) and IL-18 in Boxer dogs were 0.19 ± 0.05 ng/ml, 46.70 ± 4.54 ng/ml, and 36.37 ± 30.59 pg/ml, whereas Ibizan Hound dogs present 0.49 ± 0.05 ng/ml, 64.55 ± 4.54 ng/ ml, and 492.10 ± 31.18 pg/ml, respectively. The GLM regression shows fifteen haplotypes with statistically significant effect on the cytokine serum levels (P < 0.05). The more relevant are IL6-CGAAG and IFNG-GCA haplotypes, which increase and decrease the IL-2, IL-8 and IFN-γ serum levels, respectively. Conclusions Haplotypes in the IFNG and IL6 genes have been correlated to serum levels of IFN-γ, IL-2 and IL-18, and a moderate effect has been found on IL8 haplotype correlated to IL-8 and IL-18 serum levels. The results indicate that the resistance to L. infantum infection could be a consequence of certain haplotypes with a high frequency in the Ibizan Hound dog breed, while susceptibility to the disease would be related to other specific haplotypes, with high frequency in Boxer. Future studies are needed to elucidate whether these differences and haplotypes are related to different phenotypes in immune response and expression gene regulation to L. infantum infections in dogs and their possible application in new treatments and vaccines.

Canine malignant lymphoma is a common neoplasia in dogs, and some studies have used dogs as a research model for molecular mechanisms of lymphomas in humans. In two species, chemotherapy is the treatment of choice, but the resistance to conventional anticancer drugs is frequent. The knowledge of molecular mechanisms of development and progression of neoplasia has expanded in recent years, and the underlying epigenetic mechanisms are increasingly well known. These studies open up new ways of discovering therapeutic biomarkers. Histone deacetylases and demethylase inhibitors could be a future treatment for canine lymphoma, and the use of microRNAs as diagnosis and prognosis biomarkers is getting closer. This review summarises the epigenetic mechanisms underlying canine lymphoma and their possible application as treatment and biomarkers, both prognostic and diagnostic.

Dogs are considered the main reservoir of several zoonoses endemic to the Mediterranean Basin. In this study, a prevalence of infections and coinfections of canine vector-borne diseases was analyzed in apparently healthy dogs of different canine pure breeds in Sicily (Italy), where these diseases are endemic. The seroprevalence of Leishmania infantum, Ricketsia ricketsii, Anaplasma phagocytophilum, and Erlichia canis was assessed, as single and coinfections. Biochemical and hematological parameters were evaluated, and epidemiological factors, including sex, age, and canine breed, were recovered. The most frequent infection was L. infantum (45.61%), following R. ricketsii (36.84%), both as single, double, or triple coinfections. Coinfections change the biochemical and hematological parameters of the host, and canine breeds are related to the infection frequency and the parameters observed during infections. Changes in the complete blood count (CBC) and biochemical values also differ between canine breeds, with the Cirneco dell’Etna dogs infected with L. infantum being the animals presenting the most interesting results in our study. High values of RBC, hemoglobin, hematocrit, mean corpuscular hemoglobin (MCH), the albumin/globulin (A/G) ratio, and albumin and low levels of β-2 globulin and γ-globulin were found only in this canine breed, suggesting some resistance to infection in these dogs. Future studies about the immune response of this canine breed could be interesting to determine their possible resistance to zoonotic pathogens, such as L. infantum.

Background:Canine behaviour problems seen by speciality behaviouralmedicine services often involve chronic anxiety disorders that have resultedin maladaptation of the individual to its environment. Common stressorsinclude the presence of other individuals (other dogs or people), noise andbeing alone. The treatment of these behavioural problems usually includesa combination of behaviour modification, environmental modification andbiological therapies. Within the latter, anxiolytic drugs such as clomipramineor fluoxetine have proven useful.Methods:Here, we present a retrospectively analysed series of 32 cases thatwere treated with the anxiolytic drug mirtazapine, which is widely used inhuman medicine but has not previously been reported for the treatment ofbehavioural problems in dogs (although it is marketed as an appetite stimu-lant in cats). Cases included dogs with a range of anxiety-related behaviouralproblems.Results:Eighty-one percent of dogs that presented with a behavioural prob-lem showed improvement and suspected adverse effects were mild andtolerable.Limitations:Further studies are required to isolate this result from the othertherapeutic measures and to compare its efficacy with other drugs.Conclusion:Mirtazapine appears to be a suitable and safe option for thetreatment of anxiety-related behavioural problems in dogs.

Background:Ensuring patient safety during small animal anaesthesia is cru-cial. This study aimed to assess anaesthetic-related deaths in dogs globally,identify risks and protective factors and inform clinical practice.Methods:This prospective cohort multicentric study involved 55,022 dogsfrom 405 veterinary centres across various countries. Data on anaesthesia-related deaths from premedication to 48 hours post-extubation werecollected. Logistic regression was used to analyse patient demographics,American Society of Anesthesiologists (ASA) classification, procedure typeand anaesthetic drugs used.Results:Anaesthetic-related mortality was 0.69%. Most deaths occurred post-operatively (81%). Age, obesity and a higher ASA classification score wereassociated with increased mortality. Urgent procedures, non-urgent butunscheduled anaesthesias and short procedures also had higher mortality.Some sedatives, systemic analgesics, hypnotics and the use of locoregionalanaesthesia were linked to a decrease in mortality.Limitations:The limitations of the study include the non-randomised sam-ple, potential selection bias, lack of response rate quantification, variable dataquality control, subjectivity in classifying causes of death and limited analysisof variables.Conclusion:Careful patient evaluation, drug selection and monitoring canbe associated with reduced mortality. These findings can be used to developguidelines and strategies to improve patient safety and outcomes. Furtherresearch is needed to refine protocols, enhance data quality systems andexplore additional risk mitigation measures.

Leishmaniosis is considered the most important neglected tropical disease caused by protozoan parasites in Southern European countries such as Spain. Its main etiological agent is Leishmania infantum while Phlebotomus perniciosus and Phlebotomus ariasi are the main vectors in the country. During the first half of July 2021, an entomological survey was conducted in a dog shelter and its surroundings in the municipality of Toledo (Castilla-La Mancha). Sand fly sticky traps, made of A5-size white paper coated with castor oil, were placed in six different environments inside a 200 m (the mean flight distance of Phlebotomus sp.) radius from the animal shelter. Sticky traps were set for eleven consecutive trapping nights in each site. A total of 356 phlebotomine sand flies belonging to four species in two genera were identified. These species and their abundance in the traps were: Sergentomyia minuta (70.2%), Phlebotomus perniciosus (25.9%), Phlebotomus sergenti (2.8%), and Phlebotomus papatasi (1.1%). The following list gives a breakdown of the abundance of phlebotomine sand flies found in various locations: a burrow (45.1%), a maintenance warehouse (21.3%), a holm oak´s tree hole (15.6%), an abandoned cattle barnyard (10.3%), a dog kennels area (4.3%), and surroundings of a feral feline colony (3.3%). Phlebotomus papatasi, an anthropophagic species, was only found in crevices of the maintenance warehouse. Although dogs are considered the main Leishmania reservoir, this preliminary research shows the effect of different micro-environments in the surroundings of animal shelters on sand fly abundance and diversity, and the importance that other reservoirs could play as most documented captures were associated with glires (orders Rodentia and Lagomorpha) rather than dogs and cats.

Failure in antibiotic therapies due to the increase in antimicrobial-resistant (AMR) bacteria is one of the main threats to public and animal health. In recent decades, the perception of companion animals has changed, from being considered as a work tool to a household member, creating a family bond and sharing spaces in their daily routine. Hence, the aim of this study is to assess the current epidemiological situation regarding the presence of AMR and multidrug resistance (MDR) in companion animals in the Valencia Region, using the indicator bacteria Escherichia coli as a sentinel. For this purpose, 244 samples of dogs and cats were collected from veterinary centres to assess antimicrobial susceptibility against a panel of 22 antibiotics with public health relevance. A total of 197 E. coli strains were isolated from asymptomatic dogs and cats. The results showed AMR against all the 22 antibiotics studied, including those critically important to human medicine. Moreover, almost 50% of the strains presented MDR. The present study revealed the importance of monitoring AMR and MDR trends in companion animals, as they could pose a risk due to the spread of AMR and its resistance genes to humans, other animals and the environment they cohabit.