Phospholipid transfer protein activity in two cholestatic patients.
BACKGROUND
Plasma phospholipid transfer protein mediates the transfer of phospholipids from triglyceride-rich lipoproteins, very low density lipoproteins and low density lipoproteins to high density lipoproteins, a process that is also efficient between high density lipoprotein particles. It promotes a net movement of phospholipids, thereby generating small lipid-poor apolipoprotein AI that contains particles and subfractions that are good acceptors for cell cholesterol efflux.


METHODS
We measured the activity of plasma phospholipid transfer protein in two cholestatic patients, assuming that changes in activity would occur in serum that was positive for lipoprotein X. Both patients presented severe hypercholesterolemia, high levels of low density lipoprotein cholesterol and, in one case, low levels of high density lipoprotein cholesterol and high levels of phospholipid serum. The phospholipid transfer activity was close to the lower limit of the reference interval. To our knowledge, this is the first time such results have been presented. We propose that phospholipid transfer protein activity becomes reduced under cholestasis conditions because of changes in the chemical composition of high density lipoproteins, such as an increase in phospholipids content. Also, lipoprotein X, which is rich in phospholipids, could compete with high density lipoproteins as a substrate for phospholipid transfer protein.
de Faria
Eliana Cotta
EC
Department of Internal Medicine, Lipids Laboratory and Experimental Medicine and Surgery Center, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil. cotta@fcm.unicamp.br
Gebrin
Adriana Celeste
AC
Nadruz Júnior
Wilson
W
Castilho
Lucia Nassi
LN
D000328:Adult; D001053:Apolipoproteins / Q000097:blood; D002779:Cholestasis / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood; D004587:Electrophoresis, Agar Gel; D005260:Female; D006801:Humans; D008073:Lipoprotein-X / Q000097:blood*; D008297:Male; D008875:Middle Aged; D049294:Phospholipid Transfer Proteins / Q000378:metabolism*; D010743:Phospholipids / Q000097:blood
D001053:Apolipoproteins; D008073:Lipoprotein-X; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids; D002784:Cholesterol