Relationship between plasma insulin concentration and plasma remnant lipoprotein response to an oral fat load in patients with type 2 diabetes

OBJECTIVES The goal of this study was to evaluate the relative effects of h yperglycemia and hyperinsulinemia on postprandial remnant lipoprotein (RLP) concentrations in newly diagnosed type 2 diabetics. BACKGROUND Increases in fasting RLP concentration have been described in ty pe 2 diabetics, as well as in insulin-resistant nondiabetics. Given the ath erogenicity of RLPs, we have extended these observations by assessing postp randial RLP concentrations and observing that hyperglycemia was necessary f or the increase in RLP concentrations. METHODS Patients with type 2 diabetes were subdivided on the basis of their plasma insulin response to oral glucose into hyperinsulinemic (H-DM) and n ormoinsulinemic (N-DM) groups of 15 patients each. Plasma triglyceride (TG) , RLP-TG and RLP cholesterol (RLP-C) concentrations were determined before and 2 and 4 h after an oral fat load in these patients and 10 control (CTL) subjects. RESULTS Plasma TG, RLP-TG and RLP-C concentrations peaked 2 h after the fat load in the CTL group, returning to baseline within 4 h. In contrast, conc entrations of these variables increased throughout the 4-h study in both gr oups of patients with type 2 diabetes. Total integrated plasma RLP-TG and R LP-C responses above baseline after the oral fat load were significantly hi gher in the H-DM group compared with the CTL (p = 0.019 and 0.009, respecti vely) or N-DM (p = 0.026 and 0.029, respectively) groups Post-heparin lipop rotein lipase activities and apo E phenotypes were similar in the H-DM and N-DM groups. CONCLUSIONS Remnant lipoprotein response to an oral fat load is significant ly increased in hyperinsulinemic patients with type 2 diabetes. These chang es may increase the risk of coronary heart disease in these individuals. (C ) 2001 by the American College of Cardiology.