Metabolism of triglyceride-rich lipoproteins and lipid transfer to high-density lipoprotein in young obese and normal-weight patients with polycystic ovary syndrome.

OBJECTIVE: To clarify whether the metabolism of triglyceride-rich lipoproteins and lipid transfer to high-density lipoprotein (HDL) are altered in patients with polycystic ovary syndrome (PCOS).

DESIGN: Case-control study.

SETTING: Endocrinology clinics.

PATIENT(S): Eight normal-weight (NW) and 15 obese (Ob) patients with PCOS were compared with 10 NW and 10 Ob women without PCOS paired for age and body mass index.

INTERVENTION(S): Determination of triglyceride-rich lipoprotein metabolism and lipid transfer to HDL.

MAIN OUTCOME MEASURE(S): Participants were injected triglyceride-rich emulsions labeled with (14)C-cholesteryl esters and (3)H-triglycerides and the fractional clearance rate (FCR, in min(-1)) of labels was determined. Lipid transfer from artificial nanoemulsions to HDL was performed by incubating radioactively labeled lipid nanoemulsions with plasma during 1 hour, followed by radioactive counting of HDL-containing supernatant after chemical precipitation.

RESULT(S): Lipolysis estimated by triglyceride FCR was equal in PCOS groups (NW = 0.043 +/- 0.032, Ob = 0.033 +/- 0.009) and respective controls (NW = 0.039 +/- 0.015, Ob = 0.044 +/- 0.019). However, the remnant removal as estimated by cholesteryl ester FCR was reduced in both PCOS groups (NW = 0.005 +/- 0.006, Ob = 0.005 +/- 0.005) compared with controls (NW = 0.016 +/- 0.006, Ob = 0.011 +/- 0.072). Lipid transfer rates were not different among groups, but triglyceride transfer rates were positively correlated with homeostasis model assessment estimate of insulin resistance in PCOS.

CONCLUSION(S): PCOS patients showed decreased removal of atherogenic remnants even when fasting glucose was <100 mg/dL. This reinforces the usefulness of the measures taken to prevent cardiovascular events in PCOS patients.