Relationship between cobalamin-dependent metabolites and both serum albumin and alpha1 -proteinase inhibitor concentrations in hypocobalaminemic dogs of 7 different breeds.

BACKGROUND Increased serum concentrations of homocysteine (HCY) and methylmalonic acid (MMA), the 2 main cobalamin-dependent metabolites, as well as decreased serum albumin and canine alpha1 -proteinase inhibitor (cα1 -PI) concentrations have previously been described in hypocobalaminemic dogs with gastrointestinal disease. However, no studies have been conducted to evaluate potential relationships between these serum biomarkers. OBJECTIVE The aim of this study was to evaluate the relationship between HCY and MMA, 2 cobalamin-dependent metabolites, and both serum albumin and cα1 -PI concentrations in hypocobalaminemic dogs. METHODS Serum samples from 285 dogs including 7 different breeds (Beagle, Boxer, Cocker Spaniel, German Shepherd, Labrador Retriever, Chinese Shar-Pei, and Yorkshire Terrier) with hypocobalaminemia were used. Serum HCY, MMA, albumin, and cα1 -PI concentrations were determined. RESULTS There was a significant correlation between serum HCY and albumin concentrations, as well as serum HCY and cα1 -PI concentrations (ρ = 0.62 and ρ = 0.37, respectively; P < .0001). No correlations were observed between serum MMA and albumin concentrations, or cα1 -PI concentrations (ρ = 0.01 and ρ = 0.08, respectively; P > .05). In addition, significant breed-specific correlations were observed between serum MMA and albumin concentrations in German Shepherds, and serum HCY and MMA concentrations in Chinese Shar-Peis with hypocobalaminemia. CONCLUSIONS This study shows a correlation between serum albumin and cα1 -PI and HCY concentrations, but not with serum MMA concentration in dogs with hypocobalaminemia. In addition, significant breed-specific correlations were observed between serum MMA and albumin concentrations in German Shepherds, as well as serum HCY and MMA concentrations in Chinese Shar-Peis, emphasizing the unique metabolic interactions in those dog breeds affected by hypocobalaminemia.