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

Abstract

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.