Plasma proprotein convertase subtilisin kexin type 9 is a heritable trait of familial combined hyperlipidaemia

The aim of the present study was to investigate the relationship between circulating PCSK9 (proprotein convertase subtilisin kexin type?9) and FCHL (familial combined hyperlipidaemia) and, when positive, to determine the strength of its heritability. Plasma PCSK9 levels were measured in FCHL patients (n=45), NL (normolipidaemic) relatives (n=139) and their spouses (n=72). In addition, 11 FCHL patients were treated with atorvastatin to study the response in PCSK9 levels. PCSK9 levels were higher in FCHL patients compared with NL relatives and spouses: 96.1 compared with 78.7 and 82.0?ng/ml (P=0.004 and P=0.002 respectively). PCSK9 was significantly associated with both TAG (triacylglycerol) and apolipoprotein B levels (P<0.001). The latter relationship was accounted for by LDL (low-density lipoprotein)-apolipoprotein B (r=0.31, P=0.02), not by VLDL (very-low-density lipoprotein)-apolipoprotein B (r=0.09, P=0.49) in a subgroup of subjects (n=59). Heritability calculations for PCSK9 using SOLAR and FCOR software yielded estimates of 67-84% respectively (P<0.0001). PCSK9 increased from 122 to 150?ng/ml in 11 FCHL patients treated with atorvastatin (40?mg) once daily for 8?weeks (P=0.018). In conclusion, plasma PCSK9 is a heritable trait associated with both FCHL diagnostic hallmarks. These results, combined with the significant rise in PCSK9 levels after statin therapy, warrant further studies in order to unravel the exact role of PCSK9 in the pathogenesis and treatment of this highly prevalent genetic dyslipidaemia.     

Carotid intima media thickness is related positively to plasma pre ß-high density lipoproteins in non-diabetic subjects

BackgroundLipid-poor or lipid-free high density lipoprotein (HDL) particles, designated pre ß-HDL, stimulate removal of cell-derived cholesterol to the extracellular compartment, which is an initial step in the reverse cholesterol transport pathway. Pre ß-HDL levels may be elevated in subjects with established cardiovascular disease. We determined the relationship of carotid intima media thickness (IMT), a marker of subclinical atherosclerosis, with pre ß-HDL in subjects without clinically manifest cardiovascular disease.MethodsIMT and plasma pre ß-HDL, assayed by crossed immuno-electrophoresis, were determined in 70 non-diabetic subjects (aged 56 ± 9 years; non-smokers only; 27 women).ResultsIMT was correlated positively with pre ß-HDL, both expressed as plasma apolipoprotein (apo) A-I concentration (r = 0.271, p = 0.023) and as% of apo A-I (r = 0.341, p = 0.004). In contrast, IMT was correlated inversely with HDL cholesterol (r = ? 0.253, p = 0.035). IMT was also related positively to pre ß-HDL after adjustment for age, sex, systolic blood pressure (in apoA-I concentration, ß = 0.203, p = 0.043; in% of plasma apoA-I, ß = 0.235, p = 0.023). IMT remained associated with pre ß-HDL after additional adjustment for either body mass index, plasma glucose, cholesterol, triglycerides, HDL cholesterol, apoA-I and apoB.ConclusionSubclinical atherosclerosis may relate to higher plasma pre ß-HDL independently of apoA-I and HDL cholesterol levels.