Background Premature atherosclerosis is a well recognised comorbidity in patients with SLE (1). Elevated levels of circulating Oxidised Low Density Lipoprotein (OxLDL) have been described in SLE patients, especially in those with a history of cardiovascular disease (2). Paraoxonase 3 (PON 3) is believed to play a role in prevention of atherosclerosis by contributing towards the anti oxidant actions of high density lipoprotein (HDL).

Objectives To determine serum PON3 levels and PON 3 activity in patients with SLE and compare them with healthy controls.

Methods Serum PON 3 levels and PON3 activity were determined in 100 patients of SLE with no prior history of coronary artery disease and they were compared with those of 50 healthy controls who did not have diabetes, hypertension or coronary artery disease. Serum PON3 concentration was determined by enzyme-linked immunosorbent assay (ELISA) using anti-PON3 antibody specific for human PON3. PON 3 activity was estimated using Spectrophotometric assay which quantified the hydrolysis of dihydrocoumarin at 270 nm (3).

Results PON 3 levels were lower in SLE patients (P<0.001) and PON 3 activity was reduced (p<0.001) as compared to healthy controls. In subgroup analysis of SLE patients, PON 3 activity and levels did not correlate with disease activity. On Univariate analysis, serum creatinine (r²=0.06, p<0.002), age (r²=0.03, p=0.035), and SLE status (r²=0.27, p<0.001) contributed to PON3 levels. On Univariate analysis, serum creatinine (r²=0.15, p<0.001), AST (r²=0.04, p=0.01), ALT (r²=0.16, p<0.001) and SLE status (r²=0.77, p<0.001) contributed to PON3 levels. On multivariate analysis, only SLE status predicted PON 3 levels (P<0.001) and PON 3 activity (p<0.001).

Conclusions PON3 levels are reduced and PON 3 activity is decreased in patients with SLE as compared to healthy controls, the difference was attributable to the disease itself. This may contribute to premature atherosclerosis in these patients.

References

1. Nikpour M, Urowitz MB, Gladman DD. Premature atherosclerosis in systemic lupus erythematosus. Rheum Dis Clin North Am. 2005;31:329–54.

2. Frostegard J, Svenungsson E, Wu R et al. Lipid peroxidation is enhanced in patients with systemic lupus erythematosus and is associated with arterial and renal disease manifestations. Arthritis Rheum. 2005;52:192–200.

3. Draganov DI, Teiber JF, Speelman A et al. Human paraoxonases (PON1, PON2, and PON3) are lactonases with overlapping and distinct substrate specificities. J Lipid Res. 2005;46:1239–47.

References

Acknowledgements None.

Disclosure of Interest None declared