Cholesterol concentrations in lipoprotein fractions separated by anion-exchange–high-performance liquid chromatography in healthy dogs and dogs with hypercholesterolemia

Abstract

Anion-exchange (AEX)–high-performance liquid chromatography (HPLC) for measurement of cholesterol can be used to separate serum lipoproteins (high-density lipoprotein (HDL); low-density lipoprotein (LDL); intermediate-density lipoprotein (IDL); very-low-density lipoprotein (VLDL)) in humans. However, AEX–HPLC has not been applied in veterinary practice. We had three objectives: (i) the validation of AEX-HPLC methods including the correlation of serum cholesterol concentration in lipoprotein fraction measured by AEX–HPLC and gel permeation–HPLC (GP–HPLC) in healthy dogs and those with hypercholesterolemia was investigated; (ii) the reference intervals of lipoprotein fractions measured by AEX–HPLC from healthy dogs (n=40) was established; (iii) lipoprotein fractions from the serum of healthy dogs (n=12) and dogs with hypercholesterolemia (n=23) were compared. Analytic reproducibility and precision of AEX–HPLC were acceptable. Positive correlation between serum concentrations of total cholesterol (Total-Chol), HDL cholesterol (HDL-Chol), LDL cholesterol (LDL-Chol)+IDL cholesterol (IDL-Chol), and VLDL cholesterol (VLDL-Chol) was noted for AEX–HPLC and GP–HPLC in healthy dogs and dogs with hypercholesterolemia. Reference intervals measured by AEX–HPLC for serum concentrations of Total-Chol, HDL-Chol, and LDL-Chol were determined to be 2.97–9.32, 2.79–6.57, 0.16–3.28mmol/L (2.5–97.5% interval), respectively. Furthermore, there was significant difference in lipoprotein profiles between healthy and dogs with hypercholesterolemia. These results suggest that AEX–HPLC can be used to evaluate lipoprotein profiles in dogs and could be a new useful indicator of hyperlipidemia in dogs.