Oxidized low-density lipoprotein in children with familial hypercholesterolemia and unaffected siblings: effect of pravastatin.
OBJECTIVE
To assess the role of oxidized phospholipids (OxPLs) in children with familial hypercholesterolemia (FH) and the effect of pravastatin.


BACKGROUND
Oxidized phospholipids are a major component of oxidized low-density lipoprotein (OxLDL) and are bound to lipoprotein (a) [Lp(a)]. The significance of OxPL markers in children is unknown.


METHODS
Children with FH were randomized to placebo (n = 88) or pravastatin (n = 90) after instruction on American Heart Association step II diet. Unaffected siblings (n = 78) served as controls. The OxPL content on apolipoprotein B-100 (apoB) detected by antibody E06 (OxPL/apoB ratio), immunoglobulin (Ig)G and IgM immune complexes per apoB (IC/apoB) and on all apoB particles (total apoB-IC = IC/apoB multiplied by plasma apoB levels), autoantibodies to malondialdehyde (MDA)-low-density lipoprotein (LDL), Lp(a), and apoB levels were measured at baseline and after two years of treatment.


RESULTS
Compared with unaffected siblings, children with FH had significantly lower levels of OxPL/apoB but higher levels of IgG and IgM total apoB-IC and IgM MDA-LDL autoantibodies. From baseline to two-year follow-up, compared with placebo pravastatin treatment resulted in a greater mean percentage change in apoB (-18.7% vs. 0.3%; p = 0.001), total IgG apoB-IC (-31.9% vs. -12.2%; p < 0.001), and total IgM apoB-IC (-25.5% vs. 13.2%; p = 0.001). Interestingly, pravastatin also resulted in higher OxPL/apoB (48.7% vs. 29.3%; p = 0.028) and Lp(a) levels (21.9% vs. 10.7%; p = 0.044).


CONCLUSIONS
Compared with unaffected siblings, children with FH are characterized by elevated levels of apoB-IC and IgM MDA-LDL autoantibodies. Compared with placebo, pravastatin led to a greater reduction in apoB-IC but also to a greater increase in OxPL/apoB and Lp(a), which may represent a novel mechanism of mobilization and clearance of OxPL.
Rodenburg
Jessica
J
Department of Vascular Medicine, University of Amsterdam, Amsterdam, The Netherlands.
Vissers
Maud N
MN
Wiegman
Albert
A
Miller
Elizabeth R
ER
Ridker
Paul M
PM
Witztum
Joseph L
JL
Kastelein
John J P
JJ
Tsimikas
Sotirios
S