Polycystic ovary syndrome influences the level of serum amyloid A and activity of phospholipid transfer protein in HDL2 and HDL3

Study question Is polycystic ovary syndrome (PCOS) associated with altered levels of pro-inflammatory high-density lipoproteins (HDL) and activity of HDL-associated enzymes? Summary answer In PCOS, HDL contained increased levels of the inflammatory marker serum amyloid A (SAA) and altered functioning of HDL-associated phospholipid transfer protein (PLTP), with these changes being independent of BMI, body fat and insulin resistance (IR). What is known already PCOS is associated with adipocyte-derived inflammation, which potentially increases the risk of cardiovascular disease and diabetes. SAA is an inflammatory marker that is released from hypertrophic adipocytes and interacts with HDL, reducing their anti-atherogenic properties. No studies have previously investigated if SAA-associated HDL influences the HDL-associated enzymes namely, PLTP and cholesterol ester transfer protein (CETP) in women with PCOS. Participants/materials, settings, methods Obese women with PCOS were matched with controls for BMI and percentage body fat (n = 100/group; cohort-1); a subset of these women (n = 64/group; cohort-2) were further matched for IR. HDL in blood samples was subfractionated into HDL₂ and HDL₃ by rapid ultracentrifugation. SAA was measured in serum, HDL₂ and HDL₃ by an enzyme-linked immunosorbent assay and the activities of PLTP and CETP were measured in HDL₂ and HDL₃ by fluorimetric assays. Main results and the role of chance In the PCOS women from cohort-1, SAA was increased in serum, HDL₂ and HDL₃ (P = 0.038, 0.008 and 0.001 versus control, respectively), as was the activity of PLTP in HDL₂ and HDL₃ (P = 0.006 and 0.009 versus controls, respectively). In the PCOS women from cohort-2, SAA was increased in serum, HDL₂ and HDL₃, although only significantly in HDL₃ (P = 0.083, 0.120 and 0.034 versus controls, respectively), as was the activity of PLTP in HDL₂ and HDL₃, although this was only significant in HDL₂ (P = 0.045 and 0.070 versus controls, respectively). Limitations, reasons for caution First, insulin sensitivity was not determined by the euglycaemic-hyperinsulinaemic clamp. Secondly, the method used to estimate body fat was not able to discriminate between visceral and peripheral fat. Thirdly, larger study groups would be required to confirm if PCOS independently contributed to SAA-related HDL and functional changes to this lipoprotein, independent of BMI, percentage body fat and IR. Wider implications of the findings This is the first study to highlight the usefulness of HDL-associated SAA as a marker to identify increased inflammation in women with PCOS. This study also identified that the functioning of HDL was altered in women with PCOS. These findings illustrate a mechanism through which cardiovascular disease may increase in PCOS. Study funding/competing interests Funded by the Irish Endocrinology Society. No competing interests. Clinical trial registration number NCT001195168.