A simple method for the measurement of total and glycated apolipoprotein B and its relevance to apolipoprotein-B metabolism in diabetes mellitus.

By the combination of boronate affinity chromatography on micro columns and immunoturbidimetry, a method was developed for the measurement of glycated apoliprotein B (Apo-B). The overall precision of the method was 11%. The sensitivity was 0.3 mg/l Apo-B or 0.05% glycated Apo-B, which is far below physiological levels. The recovery after column separation was 95 +/- 7%. In vitro incubation of plasma with 90 mmol/l D-glucose showed an increase in the percentage glycated Apo-B of 0.58% per hour. The simplicity of the method makes it suitable for screening purposes. Non-diabetic patients (n = 21) and diabetic patients (n = 35) were screened for glycated and total Apo-B. Total Apo-B in diabetics (1.02 +/- 0.53 g/l) was increased (controls: 0.75 +/- 0.18 g/l; p less than 0.05) and a positive correlation between HbA1 and Apo-B (r = 0.36, p less than 0.05) was present in this group. However, no significant difference of glycated Apo-B was measured between diabetics and controls (10.4 +/- 2.8 and 11.5 +/- 1.4%, respectively). The possible implications of these findings are discussed.