Elevated remnant-like lipoprotein particles in impaired glucose tolerance and type 2 diabetic patients

Impaired glucose tolerance (IGT) in association with insulin resistance is considered to be a risk factor for atherosclerosis. Thus, patients with IGT may have abnormal lipid and lipoprotein profiles. The purpose of this study was to investigate presence of remnant-type hyperlipoproteinemia in patients with IGT.

Serum levels of remnant-like lipoprotein particles (RLP) were measured in 541 subjects (362 men and 179 women, age 53 +/- 7.9 years) who visited our health center for routine medical examinations. We measured RLP cholesterol (RLP-C) and RLP triglycerides (RLP-TG) using immunoaffinity gel containing monoclonal anti-human apoproteins A-I (H-12) and B-100 (JI-H) antibodies. After a 75-g oral glucose tolerance test, subjects were divided into three groups: normal, IGT, and type 2 diabetic.

After matching for sex, age, and body weight, serum RLP-C in normal, IGT, and diabetic groups were 4.2 +/- 1.7, 6.2 +/- 3.4, and 6.2 +/- 4.2 mg/dl, respectively. The corresponding RLP-TG values were 16.7 +/- 9.2, 28.0 +/- 19.1, and 29.0 +/- 27.2 mg/dl. We found that RLP-C and RLP-TG values were significantly higher in the IGT and diabetic groups compared with the normal group (P < 0.001). In the same order, total serum cholesterol levels were 206 +/- 29, 205 +/- 34, and 206 +/- 34 mg/dl and LDL cholesterol levels were 127 +/- 27, 124 +/- 34, and 123 +/- 34 mg/dl, showing no marked difference in these groups. However, serum levels of triglyceride were higher in the IGT and diabetes groups (155 +/- 76 and 151 +/- 81 mg/dl vs. 106 +/- 41 mg/dl; P < 0.0001). Further, the incidence of remnant hyperlipoproteinemia in normocholesterolemic subjects was up to four times higher in IGT and diabetic groups compared with the normal group.

High serum RLP-C and RLP-TG levels in IGT and diabetic patients may represent an increased risk of atherosclerosis in these patients.