Objective: To examine the relation between plasma lipoprotein (a) (Lp[a]) levels and oxidative stress biomarkers, serum cytokines, and atherosclerotic burden among individuals recently diagnosed as having metabolic syndrome (MS).
Methods: Eighty-four white patients with MS were classified according to two Lp(a) levels (normal Lp[a]: < 30 mg/dL or high Lp[a]: > 30 mg/dL) and were compared with 42 healthy controls. Oxidative stress biomarkers (oxidized low-density lipoprotein, antibodies to oxidized low-density lipoprotein, and nitric oxide metabolites) and proinflammatory cytokines (interleukin [IL]-2, IL-4, IL-5, IL-6, IL-10, IL-12P70, IL-13, and interferon-γ) were measured in plasma. Atherosclerotic significance was determined using carotid ultrasound and endothelial function by standardized protocols.
Results: Patients with MS had higher levels of serum cytokines, oxidative stress markers, and C-reactive protein, and greater atherosclerosis burden as compared with controls. Among the group members, 58 patients had normal Lp(a) levels and 26 had high Lp(a) levels. Cytokines and C-reactive protein levels were significantly higher in patients with high Lp(a) compared with those with normal Lp(a) (P < 0.01 for IL-2 and P < 0.001 for the others). Nitric oxide metabolites were significantly lower in patients with high Lp(a) as compared with those with normal Lp(a) (P < 0.05). No differences were found in oxidized low-density lipoprotein and atherosclerotic burden between the two groups of patients with MS with respect to Lp(a) levels.
Conclusions: Elevated Lp(a) plasma levels are associated with higher proinflammatory markers in patients newly diagnosed as having MS.