Relationship of apolipoprotein A5 and apolipoprotein C3 levels to serum triglycerides in patients with type 2 diabetes

The role of apolipoprotein A5 (ApoA5) in modulating triglyceride levels in humans is incompletely understood. Some researchers have reported modest positive correlations of ApoA5 with triglycerides while others have reported negative correlations. A recent report suggested that ApoA5 gene expression may be influenced by insulin. In type 2 diabetes, some groups have reported higher levels of ApoA5 compared to normals while others have reported lower levels. To better understand the relationships between ApoA5, apolipoprotein C3 (ApoC3), and triglycerides in type 2 diabetes, ApoA5 levels were measured and correlated with triglyceride, insulin, and HbA1c levels. ApoC3 levels were measured and correlated with triglycerides. In patients with type 2 diabetes, ApoA5 levels were elevated compared to normals, with several patients having markedly increased levels confirmed by Western blotting. ApoA5 levels were positively correlated with triglycerides ( r = 0.60) but were not correlated with either HbA1c or serum insulin levels. ApoC3 levels were highly positively correlated with triglycerides ( r = 0.88). These data indicate that in patients with type 2 diabetes ApoA5 levels are positively correlated with triglycerides but are not correlated with HbA1c or insulin levels. ApoC3 levels are strongly positively correlated with triglycerides in these patients.