A kinetic study of LDL-apoB100, using stable isotopes, was performed in 38 individuals (20 men, 18 women) including 23 non-diabetic normolipidemic subjects and 15 patients with type 2 diabetes.
In the non-diabetic group, plasma PCSK9 was positively correlated with LDL-C (r = 0.64, p = 0.001), apoB (r = 0.67, p < 0.001), and inversely correlated with LDL-apoB FCR (r = ?.61, p = 0.002). In contrast, in type 2 diabetic patients, plasma PCSK9 was not associated with LDL-C, apoB and LDL-apoB FCR. However, the lack of association between PCSK9 and LDL-apoB FCR seemed to be limited to the patients with ¡°uncontrolled?diabetes (HbA1c > 7 % ) since a borderline significant negative correlation between PCSK9 and LDL FCR (r = ?.70, p = 0.08) was retrieved in patients with HbA1c ?7 % . In multivariate analysis, LDL-apoB FCR was independently associated with PCSK9 (p = 0.001) and fasting glycaemia (log) (p = 0.030) in the non-diabetic population and with PCSK9 (p = 0.040) and HbA1c (p = 0.029) in diabetic patients.
Our data indicate that both PCSK9 and glycaemia are independent factors influencing LDL catabolism. Plasma PCSK9 influences significantly the catabolism of LDL-apoB100 in individuals without diabetes, but not in patients with uncontrolled type 2 diabetes. Thus, the influence of diabetes on LDL-apoB FCR catabolism may overwhelm the influence of PCSK9.