Feeding dogs a high-fat diet induces metabolic changes similar to natural aging, including dyslipidemia, hyperinsulinemia, and peripheral insulin resistance.

OBJECTIVE: The goal of this study was to characterize changes induced by a high-fat diet in body composition, insulin levels and sensitivity, blood lipids, and other key biomarkers also associated with the metabolic dysfunction that occurs with natural aging. ANIMALS: 24 male Beagle dogs, 3 to 7 years of age, of mixed castration status. METHODS: Dogs were randomly assigned to continue twice daily feeding of the commercial adult maintenance diet (n = 12, including 2 intact) that they were previously fed or to a high-fat diet (12, including 2 intact) for 17 weeks between December 1, 2021, and April 28, 2022. Assessments included body composition (weight, body condition score, and adipose mass determined by deuterium enrichment), clinical chemistries, plasma fatty acid quantification, oral glucose tolerance test, and histology of subcutaneous and visceral adipose biopsy samples. RESULTS: The high-fat diet led to increased body weight, body condition score, fat mass and adipocyte size, hyperinsulinemia and peripheral insulin resistance, and elevations in serum lipids, including cholesterol, triglycerides, and several species of free fatty acids. Leptin levels increased in dogs fed a high-fat diet but not in control dogs. There were no significant changes in routine clinical chemistry values in either group. CLINICAL RELEVANCE: Feeding a high-fat diet for 17 weeks led to potentially deleterious changes in metabolism similar to those seen in natural aging in dogs, including hyperinsulinemia, insulin resistance, and dyslipidemia. A high-fat diet model may provide insights into the similar metabolic dysfunction that occurs during natural aging.

Do it yourself or send for help? Considering specialty referral from a general practitioner perspective.

General practice veterinarians (GPs) are often faced with the question of which services they should provide themselves and which are more appropriately the province of board-certified specialists. The growing availability of specialty care, the expectations of many pet owners for advanced care resembling that which they receive, the expanding availability of new and more technologically sophisticated interventions, and many less easily defined shifts in the economic and cultural context of veterinary medicine all add to the pressure to limit services in general practice and refer more patients to specialists. However, the criteria for making decisions about referral are often ill-defined and controversial. Furthermore, most GPs are trained by specialists in secondary or tertiary care institutions, providing them with a perspective that may not reflect the realities of the general practice environment.While each referral decision for a specific patient must be made in the unique context of that case, reflection and discussion concerning relevant general principles can help GPs build a rational foundation for making such decisions. The principles and methods of evidence-based medicine and the expanding concept of a spectrum of care can usefully inform decision-making about referral. It is also critical that all stakeholders contribute to discussion of these questions and to the training of veterinarians so that the next generation will be prepared to shape and embody the role of GP in a manner that best meets the needs of patients, pet owners, and veterinarians themselves.

Body weight, gonadectomy, and other risk factors for diagnosis of osteoarthritis in companion dogs.

Objective: The aim of this study is to evaluate age, sex, body weight, breed, neuter status, and age at neutering as risk factors for diagnosis of osteoarthritis in companion dogs. Animals: Dogs seen as patients at Banfield Pet Hospital in the United States from 1998 to 2019 with a date of death in 2019. The final cohort consisted of 131,140 dogs. Methods: In this retrospective cohort study, Cox proportional hazard models were used to test for associations between osteoarthritis incidence and age at baseline, sex, maximum body weight, maximum body condition score, neuter status, and age at neutering. The same model was used to test these associations in 12 representative breeds, chosen based on breed weight and sample size. Results: Older age, higher adult body weight, gonadectomy, and younger age at gonadectomy were significantly associated with higher risks of osteoarthritis in the total cohort and in all 12 breeds evaluated. Higher body condition scores and sex were also significantly associated with osteoarthritis but with minimal effect sizes in the overall cohort, and these risk factors were not consistently significant in all breeds tested. Clinical relevance: These results will assist veterinarians in identifying dogs at higher risk for osteoarthritis and applying appropriate diagnostic, preventative, and treatment interventions. An understanding of potentially modifiable risk factors, such as body condition and neutering, will support evidence-based discussions with dog owners about risk management in individual patients.

Evaluating instruments for assessing healthspan: a multi-center cross-sectional study on health-related quality of life (HRQL) and frailty in the companion dog.

Developing valid tools that assess key determinants of canine healthspan such as frailty and health-related quality of life (HRQL) is essential to characterizing and understanding aging in dogs. Additionally, because the companion dog is an excellent translational model for humans, such tools can be applied to evaluate gerotherapeutics and investigate mechanisms underlying longevity in both dogs and humans. In this multi-center, cross-sectional study, we investigated the use of a clinical questionnaire (Canine Frailty Index; CFI; Banzato et al., 2019) to assess frailty and an owner assessment tool (VetMetrica HRQL) to evaluate HRQL in 451 adult companion dogs. Results demonstrated validity of the tools by confirming expectations that frailty score increases and HRQL scores deteriorate with age. CFI scores were significantly higher (higher frailty) and HRQL scores significantly lower (worse HRQL) in old dogs (≥ 7 years of age) compared to young dogs (≥ 2 and < 6 years of age). Body size (small < 11.3 kg (25 lbs) or large > 22.7 kg (50 lbs)) was not associated with CFI or total HRQL score. However, older, larger dogs showed faster age-related decline in HRQL scores specific to owner-reported activity and comfort. Findings suggest that the clinician-assessed CFI and owner-reported VetMetrica HRQL are useful tools to evaluate two determinants of healthspan in dogs: the accumulation of frailty and the progressive decline in quality of life. Establishing tools that operationalize the assessment of canine healthspan is critical for the advancement of geroscience and the development of gerotherapeutics that benefit both human and veterinary medicine. Graphical summary of the design, results, and conclusions of the study.

Assessment and Management of Declining Physical Function in Aging Dogs.

Aging is the leading cause of disability, disease, and death in adult dogs. One major consequence of aging is diminishing physical function. For normal functioning, basic elements such as strength, balance, and energy must be present. These must then be integrated to enable higher levels of function, from simple walking and feeding to the complex demands of social roles, such as family companion or working search-and-rescue dog. Biological aging processes, such as loss of muscle strength, diminished cardiorespiratory function, chronic inflammation, and age-associated diseases, as well as the adverse effects of medical treatments, all contribute to physical dysfunction. Contextual elements, such as lack of opportunity for physical exercise or restricted access to veterinary care due to owner socioeconomic circumstances, also influence age-associated functional decline in dogs. In humans, well-established clinical assessments are available to evaluate physical function, and these can predict disability, morbidity, and mortality. There are also well-supported interventions that preserve and restore function and reduce the risk of death and disease in the elderly. Because the fundamental biology and the clinical phenotype of aging are very similar in humans and dogs, these assessments and interventions can likely be adapted for use in mitigating declining physical function in geriatric canines. This review evaluates the decline in physical function with age in dogs and the potential utility in this species of clinical assessment tools and interventions developed for humans.

Canine Geriatric Syndrome: A Framework for Advancing Research in Veterinary Geroscience.

Biological aging is the single most important risk factor for disease, disability, and ultimately death in geriatric dogs. The effects of aging in companion dogs also impose significant financial and psychological burdens on their human caregivers. The underlying physiologic processes of canine aging may be occult, or early signs of aging may be ignored because of the misconception that biological aging is natural and therefore inevitable. The ability to detect, quantify, and mitigate the deleterious processes of canine aging would greatly enhance veterinary preventative medicine and animal welfare. In this paper we propose a new conceptual framework for aging in dogs, the Canine Geriatric Syndrome (CGS). CGS consists of the multiple, interrelated physical, functional, behavioral, and metabolic changes that characterize canine aging as well as the resulting clinical manifestations, including frailty, diminished quality of life, and age-associated disease. We also identify potential key components of a CGS assessment tool, a clinical instrument that would enable veterinarians to diagnose CGS and would facilitate the development and testing of interventions to prolong healthspan and lifespan in dogs by directly targeting the biological mechanisms of aging. There are many gaps in our knowledge of the mechanisms and phenotype of aging in dogs that must be bridged before a CGS assessment tool can be deployed. The conceptual framework of CGS should facilitate identifying these gaps and should stimulate research to better characterize the processes and effects of aging in dogs and to identify the most promising preventative strategies to target these.

Comparative veterinary geroscience: mechanism of molecular, cellular, and tissue aging in humans, laboratory animal models, and companion dogs and cats.

Aging is the single most important cause of disease, disability, and death in companion animal species. Contrary to the common view of aging as mysterious and inevitable, it is more usefully understood as a set of complex but comprehensible and modifiable biological processes that are highly conserved across species. The purpose of this Currents in One Health manuscript is to describe key mechanisms of aging at the cellular and molecular level and the manifestations of these in the tissues of the musculoskeletal system, adipose, and the brain. The characteristics of these processes as identified in common laboratory animal models and in humans will be described and compared with the much more limited information available concerning aging in dogs and cats. This will highlight important targets for future research in these species. The consistent patterns across species in the hallmarks of aging and their manifestations at the level of tissues, organ systems, and individual animals signify potential targets for interventions to mitigate the negative health impacts of aging and extend both life span and health span (the period of life free of significant disease or disability). Further research to elucidate aging mechanisms in companion dogs and cats will eventually support development, testing, and implementation of clinical therapies to prevent and ameliorate age-related dysfunction, disease, and death.

The phenotype of aging in the dog: how aging impacts the health and well-being of dogs and their caregivers.

Aging is the single most important cause of disease, disability, and death in adult dogs. Contrary to the common view of aging as a mysterious and inevitable natural event, it is more usefully understood as a set of complex but comprehensible biological processes that are highly conserved across species. Although the phenotypic expression of these processes is variable, there are consistent patterns both within and between species. The purpose of this feature is to describe the patterns currently recognized in the physical and behavioral manifestations of aging in the dog and how these impact the health and welfare of companion dogs and their human caregivers. Important gaps in our knowledge of the canine aging phenotype will be identified, and current research efforts to better characterize aging in the dog will be discussed. This will help set the context for future efforts to develop clinical assessments and treatments to mitigate the negative impact of aging on dogs and humans.