Lipoprotein (a) concentration and apolipoprotein (a) phenotype in subjects with type 2 diabetes mellitus

To investigate the apolipoprotein (a) [apo(a)] polymorphism in the patients with type 2 diabetes mellitus and its relationship with complications.

In this study, we tested apo(a) phenotype via modified Utermann and Guo method in the 40 non-diabetic controls and 176 subjects with type 2 diabetes and analyzed the relationship between apo(a) phenotypes and micro- and macrovascular complications, including nephropathy, neuropathy, retinopathy, hypertension, coronary heart disease and cerebral infarction.

Among the 40 non-diabetic controls, the frequencies of S3S2, S4 and S4S2 were 20%, 70% and 10% respectively and the serum lipoprotein (a) [Lp(a)] level was 0.08 +/- 0.07 mg/L. While the frequencies of S2, S3, S3S2, S4, S4S2, S4S3 were 18.18%, 20.45%, 17.05%, 34.09%, 4.55% and 5.68% in the diabetics and the Lp(a) concentration was 0.13 +/- 0.11 mg/L, with significant difference between the diabetics and non-diabetic controls. In comparison with the diabetics without complications, the frequency of apo(a) phenotype significantly differed in patients with nephropathy, nephropathy, hypertension, coronary heart disease and cerebral infarction except for diabetic retinopathy. In comparison with patients with S2 phenotype, the levels of fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG) and glycated hemoglobin A1c (HbA1c) were lower in patients with S4 phenotype. The concentration of Lp(a) and urine albumin index (Alb/Cr) were significantly different among diabetics with different apo(a) phenotype, the highest being in patients with S2, secondly S3, and the lowest S4.

There were significant differences in the frequency of apo(a) phenotype between subjects with type 2 diabetes and non-diabetic controls, and also in diabetics with or without microvascular and macrovascular diseases. The underlying linkage might be microalbuminuria and insulin resistance.