Aim: Small dense (sd)-low-density lipoprotein (LDL) is a potent atherogenic lipoprotein. The overall atherogenicity of this lipoprotein can be precisely assessed by quantifying sd-LDL rather than by measuring the LDL size. We studied the effects of representative lipid-lowering agents (statin and fibrate) on sd-LDL-cholesterol (C) in patients with type 2 diabetes.
Methods: Sd-LDL-C was measured by the precipitation method established by Hirano and Ito. Large buoyant (lb)-LDL-C was calculated by subtracting sd-LDL-C from LDL-C. Type 2 diabetes patients (n=72) were administered lipid-lowering agents for three months: patients with hypercholesterolemia received 1 mg of pitavastatin and those with hypertriglyceridemia received 100 mg of micronized fenofibrate.
Results: Pitavastatin reduced LDL-C by 25% and reduced TG by 8%. The statin decreased sd-LDL-C by 26%, and lb-LDL-C by 22%. Fenofibrate reduced TG by 38% and increased HDL-C by 14%. The fibrate decreased sd-LDL-C by 23% without changing LDL-C. The pitavastatin-induced reduction of sd-LDL-C was significantly correlated with the reduction of LDL-C and apo B, whereas the fenofibrate-induced reduction of sd-LDL-C was correlated with the reduction of TG.
Conclusion: Both statin and fibrate reduce the potency of atherogenic sd-LDL particles, but via different mechanisms: the former decreases total-LDL including sd-LDL, while the latter decreases sd-LDL specifically.