Biomarkers of Ageing in Dogs

Abstract Gerontology is a major research topic in veterinary medicine. Although several reports have shown that aging in companion dogs is similar to human aging, there are few reports on changes in biomarker levels in aged dogs. The purpose of this preliminary study was to evaluate the differences in biomarker levels between young and old companion dogs, focusing on cardiovascular and musculoskeletal biomarkers. The young dogs included those aged under 36 months (n = 16, 19.8 ± 9.3 months), while the old ones included those aged over 108 months (n = 16, 155.8 ± 22.8 months). All dogs were referred to our university due to patellar luxation. The mean weight of the young and old dogs was 2.9 ± 0.9 kg and 4.0 ± 1.1 kg, respectively. We measured the serum concentrations of brain-derived neurotrophic factor (BDNF), osteoprotegerin (OPG), angiotensin II (ANGII), and endothelin-1 (ET-1) in both groups. Although the concentrations of BDNF did not differ between the two groups, the OPG, ANGII, and ET- 1 levels were significantly higher in the old companion dogs than in the young dogs. The results showed that the concentration of some biomarkers may increase as dogs age, especially OPG, ANGII, and ET- 1. This may inspire further research on osteoporosis and cardiovascular diseases in elderly dogs.