Salivary Vasopressin as A Potential Non-Invasive Biomarker of Anxiety in Dogs Diagnosed with Separation-Related Problems

Performance and overview of clinically relevant areas of application of saliva testing in the cat

Introduction

The cat represents an important model in order to investigate basic physiological knowledge of salivary secretion as well as pharmacokinetics of active substances.

Objective

The aim of the study was to review in which diagnostic application areas saliva testing is routinely used and in which areas it could be further explored in the future.

Materials and methods

Literature relevant to the research question was collected in March 2022 using the Pubmed database.

Results

The diagnosis of infectious diseases in cat saliva is one of the most important fields of application. Saliva diagnostics may also indicate dental diseases, allergies or kidney and other metabolic diseases. Sexual and stress hormones can also be measured in cat saliva. A number of clinically relevant allergens in cat saliva that may cause allergies in humans has been investigated and described, in addition to infectious agents that can be transmitted from cats to humans.

Conclusions

Saliva testing in cats can be useful in many areas, including the detection of infectious diseases, allergies and dental disease. However, it is far from being used to its full potential within veterinary medicine.

Saliva Malondialdehyde Concentration of Dogs With and Without Periodontal Disease

The study investigated whether malondialdehyde (MDA), a biomarker for oxidative stress, can be used as a viable parameter in dog saliva for the diagnosis or early detection of periodontal disease (PD). Saliva MDA concentrations were measured preoperatively in dogs diagnosed with PD during dental prophylaxis and compared with those of dentally healthy dogs. 35 dogs were included in the study. The average MDA concentration was 270 ng/ml (range 27-633) in the dogs without PD (n = 10) and 183 (36-833) ng/ml (ng/ml) in the dogs with PD (n = 25). The maximum MDA concentration in the study group (PD ≥1) was 833 ng/ml, which was significantly higher than in the study group (PD = 0) (p<0.05). The study showed that salivary MDA concentrations could not distinguish between healthy dogs and those with PD.

A six-month prospective, randomised, double-blinded, placebo-controlled, crossover, dietary trial design to investigate the potential of psychobiotics on seizure semiology and comorbidities in canine epilepsy: study protocol

BACKGROUND

Epilepsy is the most common chronic neurological disease in dogs. More than two-thirds of these patients suffer from associated behavioural comorbidities. The latter could have their origin in partially overlapping pathomechanisms, with the intestinal microbiome as a potential key link between them. The current arsenal of drugs for epilepsy management remains limited. Most canine patients continue to have seizures despite treatment and the occurrence of comorbidities is not sufficiently addressed, limiting quality of life of affected dogs and owners. Therefore, novel additional epilepsy management options are urgently needed. The microbiome-gut-brain axis may serve as a new target for the development of innovative multimodal therapeutic approaches to overcome current shortcomings in epilepsy management.

METHODS

A six-month prospective, randomised, double-blinded, placebo-controlled, crossover, dietary trial was designed to investigate the potential of the psychobiotic Bifidobacterium longum on behavioural comorbidities in canine epilepsy. Seizure semiology will be evaluated as a secondary outcome measure. Thirty-four privately owned dogs are planned to be included in the ongoing study meeting the following inclusion criteria: Dogs displaying increased anxiety/fear behaviour since the start of the idiopathic epilepsy. Tier II confidence level of the International Veterinary Epilepsy Task Force for the diagnosis of idiopathic epilepsy, with a maximum seizure interval of 3 month and a minimum of three generalised seizures within that period and chronically treated with at least one antiseizure drug without improvement in seizure frequency Each dog will receive the allocated supplement (probiotic vs. placebo) alongside its normal diet for a 3-month period. After a three-week wash out period, the second phase starts by administering the respective other supplement for another 3 months.

DISCUSSION

The current study considers modern high-quality standards for epilepsy medication trials. Common biasing effects should be limited to a possible minimum (regression-to-the mean effect, placebo effect, observer effect), ensuring a high validity and accuracy of the acquired results, thus enabling a representative nature of the efficacy of Bifidobacterium longum as add-on supplement for dogs suffering from epilepsy and its comorbidities. This publication should provide a description of the study procedure and data acquisition methods, including prognosed statistical analysis.

Pharmacokinetics and anti-nausea effects of intravenous ondansetron in hospitalized dogs exhibiting clinical signs of nausea

The purpose of this study was to evaluate the pharmacokinetics of intravenous (IV) ondansetron in a population of hospitalized dogs exhibiting clinical signs of nausea. The causes of nausea included pancreatitis, gastroenteritis, endocarditis, chemotherapy-induced nausea, diabetes mellitus and ketoacidosis, acute kidney injury with aspiration pneumonia, pyometra, uroabdomen, neoplasia, and hepatopathy. Twenty-four dogs were randomly assigned to one of the following IV ondansetron protocols: 1 mg/kg q12h, 0.5 mg/kg q12h, 1 mg/kg q8h, 0.5 mg/kg q8h. Serum was collected at 0, 0.25, 0.5, 1, 2, 4, 8, 16, and 24 h after the first dose, and nausea scores were recorded at multiple time points. Ondansetron and arginine vasopressin (AVP) concentrations were measured via high-performance liquid chromatography coupled to tandem mass spectrometry and ELISA, respectively. Noncompartmental pharmacokinetic modeling and dose interval modeling were performed. Ondansetron displayed linear pharmacokinetics. In the 0.5 mg/kg group, mean C_max  = 214 ng/ml, AUC_0-8h  = 463 ng/ml*h, and calculated half-life was 1.9 h. In the 1 mg/kg group, mean C_max  = 541 ng/ml, AUC_0-8h  = 1057 ng/ml*h and calculated half-life was 1.6 h. Serum ondansetron concentrations were not significantly different between dogs that required rescue anti-nausea medication (non-responders) and dogs that did not require rescue therapy (responders). In total, 83.3% of patients in the 0.5 mg/kg q8h, 0.5 mg/kg q12h, and 1 mg/kg q8h groups had improvement in nausea scores. In total, 66.7% of patients in the 1 mg/kg q12h group had improvement in nausea scores. In total, 33% of patients had resolution of nausea in the 0.5 mg/kg q8h, 1 mg/kg q8h, and 1 mg/kg q12h groups, and 16% of patients had resolution of nausea in the 0.5 mg/kg q12h group. AVP concentrations were highly variable and did not correlate with nausea scores. Nausea scores significantly decreased regardless of dosage protocol. AVP was not a reliable biomarker of nausea in this group of dogs.

Signs of Anxiety and Salivary Copeptin Levels in Dogs Diagnosed with Separation-Related Problems in a Short Separation Test

The need for faster diagnosis and more accurate treatment decisions in separation-related problems (SRPs) in dogs is urgent, and a more precise behavioral phenotyping and the development of biomarkers may be of great value. Vasopressin could be a potential non-invasive biomarker of anxiety in dogs with SRPs, but reliable measurement of its concentration is challenging. Here, we compared the behavior and salivary concentrations of copeptin, an arginine vasopressin surrogate, in dogs with SRPs (Case group, n = 13) and with no problems (Control group, n = 15) as they were introduced to a novel environment and subjected to a short episode of separation and reunion with the owner. Dogs in the Case group had greater odds of showing locomotory or oral behaviors during the pre- and post-separation than Controls, while the odds were significantly lower during separation. They also had greater odds of being persistent in seeking attention and proximity from the stranger during reunion. Overall, dogs with SRPs were more likely to express an anxiety-like state during the entire test than Controls, with separation from the owner, and even its anticipation, possibly accounting for this group difference. Although salivary copeptin concentrations did not differ between the two groups, a different trend was detected in Cases and Controls that is worth exploring in further validation studies involving a larger sample.

Randomized, Placebo-Controlled Prospective Clinical Trial Evaluating the Efficacy of the Assisi Anti-anxiety Device (Calmer Canine) for the Treatment of Canine Separation Anxiety

Introduction: Separation anxiety (SA) is among the most common canine behavior disorders and affects quality-of-life for dogs and their owners. Dogs with SA show signs of anxiety during absence or perceived absence of their owners. While psychoactive medications are often helpful for treating SA, dog and human factors may limit their utility. This study explored the efficacy of a pulsed electromagnetic field (PEMF) device for treatment of canine SA. Materials and Methods: In this double-blind randomized placebo-controlled study, a screening questionnaire and baseline video confirmed the diagnosis of SA. Owners treated their dog with the device twice daily for 6 weeks, completed weekly questionnaires, and noted adverse events. Videos were taken of the dog while alone at weeks 4 and 6. Behaviors were coded and categorized as negative and positive. Questionnaire and video data at weeks 4 and 6 were compared to baseline. Results: Forty client-owned dogs with moderate to severe SA completed the study. There were no differences between groups for age, weight, or sex. In owner questionnaires, no difference in behavior or overall score was found between the active and sham groups (p > 0.05). Videos of the active group compared to the sham group showed significant reduction in negative behaviors by week 6 (p = 0.036) and higher percentage of success at week 4 (Z = 2.83, p = 0.005), at week 6 (Z = 1.65, p = 0.098), and across the full study (Z = 1.99, p = 0.047). Adverse events were reported in eight dogs (6 active, 2 sham); all resolved and were unlikely to be related to treatment. Discussion: This study supports the efficacy and safety of this PEMF device for treatment of SA in dogs. Questionnaire results may not be sensitive enough to detect subtle negative behavioral states compared to video, and may not capture other owner observed behavioral changes. A caregiver placebo effect may account for some improvement seen in both groups. Video data appear better for diagnosis and monitoring dog's behavior when left alone. Future studies should assess PEMF's impact on other anxieties or combination of anxiety disorders in dogs.

Salivary stress markers in dogs: Potential markers of acute stress

Along with the growing awareness of psychological stress in companion animals, several treatments have become available to address fear- and anxiety-related behaviors in dogs. To detect vulnerable individuals and apply effective treatments, reliable evaluations that can quantify individual stress responses are in high demand. To develop measurable variables that have clinical applications, more investigations are needed to increase our knowledge. When stress responses are activated by the sympathetic-adrenal-medullary (SAM) and hypothalamic-pituitary-adrenal (HPA) axes, the immune system is also activated. Although the peripheral cortisol level is commonly used as a stress biomarker, it primarily reflects the HPA axis response and does not sufficiently reflect the complexity of the stress response. Thus, this review primarily focuses on the available salivary biomarkers that mainly reflect the acute stress response through the activity of the SAM axis and the immune system in dogs. We hope that this review will promote the validation of these biomarkers in dogs and aid in the development of future studies to evaluate stress responses in dogs.

Evaluation of salivary vasopressin as an acute stress biomarker in healthy dogs with stress due to noise and environmental challenges

Background

Stress is associated with various detrimental changes in physiological health that affect an animal’s quality of life. The hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic-adreno-medullar (SAM) axis are two main physiological pathways that constitute the stress response of an organism. Arginine vasopressin (AVP) is a mediator of the HPA axis and is known to be related to social behaviours and stress. The serum concentration of AVP is higher in more aggressive dogs and humans with post-traumatic stress disorder. Salivary biomarker analysis is a non-invasive method to assess stress. The purpose of this study was to evaluate the possibility of using salivary AVP as an acute stress biomarker in dogs. Salivary AVP concentration was measured before and after exposure to all relevant environmental stimuli (i.e. car trip to the lab, physical examination by the veterinarian, and sampling procedure,) and then after 30 min of vacuum noise exposure. Behavioural assessments, physiologic parameter assessments, and serum cortisol analysis were conducted in combination. Statistical analysis was conducted separately in the total study population, the less stressed group, and the more stressed group, respectively.

Results

Based on stress behaviour analysis scores, 28 dogs were classified into less or more stressed groups. All four physiologic parameters (blood pressure, body temperature, heart rate, and respiratory rate) were significantly increased after noise and environmental challenges, in the more stressed group. Serum cortisol did not show any significant change. Salivary AVP significantly decreased after noise and environmental stimulation in the more stressed group but not in the less stressed group. Salivary AVP and blood pressure changes were negatively correlated in the more stressed group.

Conclusion

Salivary AVP may be a potential acute stress biomarker in dogs.

Where Do We Stand in the Domestic Dog ( Canis familiaris ) Positive-Emotion Assessment: A State-of-the-Art Review and Future Directions

Although there have been a growing number of studies focusing on dog welfare, the research field concerning dog positive-emotion assessment remains mostly unexplored. This paper aims to provide a state-of-the-art review and summary of the scattered and disperse research on dog positive-emotion assessment. The review notably details the current advancement in dog positive-emotion research, what approaches, measures, methods, and techniques have been implemented so far in emotion perception, processing, and response assessment. Moreover, we propose possible future research directions for short-term emotion as well as longer-term emotional states assessment in dogs. The review ends by identifying and addressing some methodological limitations and by pointing out further methodological research needs.