Spectrophotometry and Ultracentrifugation for Measurement of Plasma Lipids in Dogs with Diabetes Mellitus

BACKGROUND There are conflicting reports of plasma lipoprotein lipid content in dogs with diabetes mellitus (DM). OBJECTIVES To determine lipoprotein lipid content of plasma of dogs with DM by spectrophotometry and ultracentrifugation; to compare lipoprotein lipid content in diabetic and healthy dogs; and to quantify apolipoprotein B-100 (ApoB) in dogs with DM. ANIMALS 22 dogs with DM and 9 healthy dogs. METHODS Cross-sectional study. Triglyceride (TG), total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) concentrations were measured by spectrophotometry. Very low-density lipoprotein cholesterol (VLDL-C) and low-density lipoprotein cholesterol (LDL-C) concentrations were calculated after ultracentrifugation. Non-HDL-C cholesterol was calculated by subtracting HDL-C from TC. ApoB was quantified by ELISA. The Mann-Whitney test was used for comparison of median lipoprotein concentrations, and Spearman's correlation was used to assess associations between ApoB and lipoprotein fractions. RESULTS All values are reported in mg/dL. Median TG (122), TC (343.5), HDL-C, (200), VLDL-C, (27) LDL-C (68), non-HDL-C (114), and ApoB (320) were significantly higher in dogs with DM, compared to healthy dogs (57, 197, 168, 12, 16, 31, and 258, respectively, P-values 0.0079, <0.001, 0.029, 0.011, <0.001, <0.001, 0.025, respectively). A significant association was found between ApoB and LDL-C (Spearman's rho = 0.41, P = 0.022) and between ApoB and non-HDL-C (Spearman's rho = 0.40, P = 0.027). CONCLUSIONS AND CLINICAL IMPORTANCE Dyslipidemia of dogs with DM is characterized by pronounced increases in LDL-C and non-HDL-C concentrations, although all lipoprotein fractions are significantly increased. Knowledge of specific lipoprotein fraction alterations in dogs with DM can enhance treatment options for diabetic dyslipidemia in dogs.