CD4+/CD8+ Ratio and Growth Differentiation Factor 8 Levels in Peripheral Blood of Large Canine Males Are Useful Parameters to Build an Age Prediction Model

Abstract

Purpose To build an age prediction model, we measured CD4+ and CD8+ cells, and humoral components in canine peripheral blood. Materials and Methods Large Belgian Malinois (BGM) and German Shepherd Dog (GSD) breeds (n=27), aged from 1 to 12 years, were used for this study. Peripheral bloods were obtained by venepuncture, then plasma and peripheral blood mononuclear cells (PBMCs) were separated immediately. Six myokines, including interleukin (IL)-6, IL-8, IL-15, leukemia inhibitory factor (LIF), growth differentiation factor 8 (GDF8), and GDF11 were measured from plasma and CD4+/CD8+ T-lymphocytes ratio were measured from PBMC. These parameters were then tested with age prediction models to find the best fit model. Results We found that the T-lymphocyte ratio (CD4+/CD8+) was significantly correlated with age (r=0.46, p=0.016). Among the six myokines, only GDF8 showed a significant correlation with age (r=0.52, p=0.005). Interestingly, these two markers showed better correlations in male dogs than females, and BGM breed than GSD. Using these two age biomarkers, we could obtain the best fit in a quadratic linear mixed model (r=0.77, p=3×10 -6 ). Conclusions Age prediction is a challenging task because of complication with biological age. Our quadratic linear mixed model using CD4+/CD8+ ratio and GDF8 level showed a meaningful age prediction.

Effect of Aging on the Immune Response to Core Vaccines in Senior and Geriatric Dogs

“…This unavoidable thymus involution is regarded as one of the main factors contributing to the loss of immune function typical of the elderly and is considered in turn a genetically programmed event (the so-called “thymus clock”) [ 15 , 17 , 21 , 29 ]. In a recent study (2022), Lee et al proposed both CD4/CD8 ratio and Growth Differentiation Factor 8 (GDF8) levels in canine blood as useful factors to use as an age prediction model for dogs, as these parameters were found to be significantly correlated with age [ 30 ].…”