Purpose: Plasma apolipoproteinM(apoM) is potentially anti-atherogenic, and has been found to be associated positively with plasma total, LDL and HDL cholesterol in humans.ApoMmay, therefore, be intricately related to cholesterol metabolism. Here, we determined whether plasma apoM is affected by statin or fibrate administration in patients with diabetes mellitus. Methods: Fourteen type 2 diabetic patients participated in a placebo-controlled crossover study which included three 8-week treatment periods with simvastatin (40mg daily), bezafibrate (400mg daily), and their combination. Results: ApoM was decreased by 7% in response to simvastatin (P < 0.05 from baseline and placebo), and remained unchanged during bezafibrate and combined simvastatin + bezafibrate administration. Plasma apoM concentrations correlated positively with apoB-containing lipoprotein measures at baseline and during placebo (P < 0.02 to P < 0.001), but these relationships were lost during all lipid lowering treatment periods. Conclusions: This study suggests that, even though plasma apoM is lowered by statins, apoM metabolism is to a considerable extent independent of statin- and fibrate-affected pathways involved in cholesterol
homeostasis.