APOLIPOPROTEIN-E AND ACTIVITY OF TRANSPORT OF CHOLESTEROL ESTERS IN TYPE IIA AND IIB HYPERLIPOPROTEINEMIA

The authors studied the activity of cholesterol esters transport (CET) , concentrations of apolipoprotein E in the blood and high density lip oproteins (HDLP) in parallel with other parameters of lipoprotein meta bolism in 79 males and 62 females. 122 of them had ischemic heart dise ase (IHD) and primary hyperlipoproteinemia (HLP). 19 healthy controls were normolipidemic. Activation of CET and relative lowering of apoE c ontent in HDLP with relevant increase in lipoproteins containing apoB were seen only in type IIB HLP. CET activity in controls was related t o a significant positive correlation with concentrations of both chole sterol (CS) and CS esters (CSE) in HDLP and HDLP3 and negative correla tion with the proportion free CS/CSE in HDLP. Opposite to normolipidem ic subjects, in type IIB HLP there was a negative relationship between CET activity and HDLP3 CS level and positive - between free CS/CSE in HDLP but not with concentration of CSE and total CS in HDLP. In type IIA HLP patients no relationships were registered between CET activity and HDLP content of total CS and CSE as well as with HDLP3 CS level. In type IIB HLP a significant correlation was found between level of H DLP CS and CET activity. Concentration of apoE in HDLP correlated with apoB level in the serum but not with quantity of HDLP CS. Patients wi th type IIA HLP exhibited a significant negative correlation between C ET activity and HDLP apoE. These patients had no dependence of CET act ivity on HDLP CS but had positive correlation between HDLP apoE and HD LP CS in the serum. Thus, defects of reverse CS transport may be induc ed not only by changes in CET activity but also by apoE distribution a mong lipoproteins of different classes.