BACKGROUND: The causes of increased cardiovascular risk in systemic lupus erythematosus
(SLE) are not understood thoroughly, although presence of traditional cardiovascular
risk factors and disease-specific agents were also proposed. In this study, we investigated
the quantitative changes in the lipid profile, as well as qualitative characteristics
of high-density lipoprotein (HDL) and markers of inflammation and disease activity
in SLE patients. METHODS: Lipoprotein levels were determined in 51 SLE patients and
49 healthy controls, matched in age and gender. HDL antioxidant capacity was determined
spectrophotometrically with a cell-free method of hemin-induced low-density lipoprotein
(LDL) oxidation. Polyacrylamide gel-electrophoresis was used for HDL subfraction analysis.
Human paraoxonase-1 (PON1) activity, apolipoprotein A1 (ApoA1) and oxidized LDL concentrations,
as well as interleukin-6, high-sensitivity C-reactive protein, serum amyloid A and
monocyte chemotactic protein-1 levels were determined. RESULTS: HDL-cholesterol and
ApoA1 concentrations decreased significantly in SLE subjects. Also, PON1 arylesterase
activity (125.65 +/- 26.87 vs. 148.35 +/- 39.34 U/L, p = 0.001) and total HDL antioxidant
capacity (165.82 +/- 58.28 % vs. 217.71 +/- 54.36 %, p < 0.001) were significantly
reduced in patients compared to controls. Additionally, all HDL subfraction concentrations
were significantly decreased in patients, while the levels of the examined inflammatory
markers were significantly elevated in SLE subjects. The latter correlated positively
with disease activity, and negatively with HDL concentration and total HDL antioxidant
capacity, respectively. PON1 arylesterase activity and erythrocyte sedimentation rate
were independent predictors of total HDL antioxidant capacity. CONCLUSIONS: Induced
by the systemic inflammation, altered composition and antioxidant activity may diminish
the anti-atherogenic effect of HDL and therefore may contribute to the increased cardiovascular
risk of SLE patients.
