Markers of inflammation and insulin resistance in dogs before and after weight loss versus lean healthy dogs

Abstract

ABSTRACT: Chronic low-grade inflammation in obesity is characterized by an increased production of pro-inflammatory cytokines that contribute to insulin resistance. For this study body composition, markers of inflammation and of insulin resistance in dogs before and after weight loss were compared to those of lean dogs. Eleven client-owned obese adult dogs underwent a weight loss program with commercial dry food for weight loss and reached an ideal body condition score (BCS) six months after the beginning of the weight loss program. A Control Group of nine dogs with ideal BCS were selected for the comparison. Shapiro-Wilk test was used to test for normality, Mann Whitney were used for non-normally distributes data, and Student t-test was used for normally distributed parameters. In the Obese Group body fat decreased from 41.6% (30.7-58.6) to 29.1% (18.6-46.3) (P<0.01) and dogs maintained lean body mass throughout the weight loss program (P>0.05). Obese dogs presented higher concentration of fructosamine, triglycerides, insulin, IGF-1 and leptin than the Control Group before weight reduction (P<0.05). Serum concentrations of triglycerides, IL-2, IL-6, TNF-α, insulin, leptin and IGF-1 decreased after weight loss (P<0.01), and these concentrations were similar to the Control Group (P>0.05), except for leptin (P<0.001). No alteration on peptide YY was found. Leptin (r=0.60, P=0.01), fructosamine (r=0.44, P=0.02) and triglycerides (r=0.40, P=0.04) concentrations correlated with the reduction of body fat. Weight loss reduced the concentrations of inflammatory and insulin resistance markers and most parameters became similar to dogs that have always been lean, reinforcing the importance of weight loss in small animal practice.