Lipoprotein particles LpA-I, LpA-I: A-II and LpB in patients with coronaryartery disease

Background: High density lipoproteins are all heterogeneous population of p articles. Two main subpopulations have been identified, one contains Apo A- I and APo A-II and is denominated LPA-I:A-II and another one contains only, Apo A-I and is denominated LPA-I. Aim: To measure the concentrations of th ese particles in patients with stable coronary artery disease. Patients and Methods: Serum lipids, A-I and B apolipoproteins, LpA- I, LPA-I. A-I and L PB particles were measured in 73 melt aged 33 to 82 years with angiographic ally documented coronary artery disease (CAD) and 33 control subjects aged 39 to 76 years. LPA-I, LPA-I. A-II and LpB were measured by a noncompetitiv e enzyme linked immunoassay using previously characterized monoclonal antib odies against Apo A-I, APoA-II and apoB. Results: Patients with CAD had sig nificantly higher mean levels of LDL cholesterol than the control group (p= 0.038). The mean concentration of LPA-I particles in patients with CAD was significantly lower (p=0.031) than in control subjects, while the concentra tion of LpA-I:A-II particles was significantly, higher (p=0.016). The perce ntage of coronary stenosis correlated negatively with LPA-I and positively with LPA-I:A-II. The best relative risk (RR) indicator in these patients wa s LDL-cholesterol. The relative risk increases 2.5 fold when LPA-I falls be low the cut-off level. Likewise, the relative risk increases 3-fold when LP A-I:A-II raises over the cut-off level. Conclusions: Our findings indicate that the quantification of LPA-I and LPA-I:A-II particles might allow, a mo re accurate evaluation of the CAD risk than HDL cholesterol. LPA-I might re present the antiatherogenic fraction of HDL.