The autoantibody expression against different source of oxidized low density lipoprotein in patients with acute myocardial infarction

Adaptive immunity is related to coronary artery disease severity after acute coronary syndrome in subjects with metabolic syndrome

Metabolic syndrome (MetS) is an inflammatory state associated with high coronary disease risk. Inflammation and adaptive immunity modulate atherosclerosis and plaque instability. We examined early changes in anti-oxidized low-density lipoprotein (LDL) (anti-oxLDL) autoantibodies (Abs) in patients with MetS after an acute coronary syndrome (ACS). Patients of both genders (n=116) with MetS were prospectively included after an acute myocardial infarction (MI) or hospitalization due to unstable angina. Anti-oxLDL Abs (IgG class) were assayed at baseline, three and six weeks after ACS. The severity of coronary disease was evaluated by the Gensini score. We observed a decrease in anti-oxLDL Abs titers (p<0.002 vs. baseline), mainly in males (p=0.01), in those under 65 y (p=0.03), and in subjects with Gensini score above median (p=0.04). In conclusion, early decrease in circulating anti-oxLDL Abs is associated with coronary disease severity among subjects with MetS.

Circulating oxidized low density lipoprotein, autoantibodies against them and homocysteine serum levels in diagnosis and estimation of severity of coronary artery disease

The oxidative hypothesis of atherosclerosis proposes that oxidative modification of low density lipoprotein (LDL) plays a critical role in atherogenesis. The evaluation of LDL oxidation in vivo is therefore very important. However, data concerning the evaluation of the above biochemical marker is very limited in clinical practice. This study was conducted to test the hypothesis that plasma levels of ox-LDL reflect atherosclerosis and determine the clinical significance in the measurement of circulating ox-LDL and autoantibodies against them as well as their correlation with homocysteine and lipid parameters in the diagnosis and severity of coronary heart disease. A total of 273 individuals were examined: 41 suffering from unstable angina pectoris (UAP), 62 from stable angina pectoris (SAP) and 170 healthy control subjects. We used a sensitive method for detecting ox-LDL that is based on a direct sandwich technique (ELISA) in which two monoclonal antibodies are directed against separate antigenic determinants on the oxidized apolipoprotein-B molecule along with another enzyme immunoassay designed to determine human antibodies to oxidized LDL (anti-oxLDL) directly in serum. Total homocysteine (HCY) was evaluated by means of a fully automated fluorescence polarization immunoassay. Patients with UAP exhibited marked elevations in oxLDL levels as compared to patients with SAP (161.2 +/- 28.4 vs. 119.2 +/- 26.6, p < 0.001) and the control subjects (67 +/- 18.8, p < 0.001). The difference in oxLDL levels between patients with SAP and the control group was also statistically significant. Similarly, patients with UAP showed marked elevations in anti-oxLDL antibodies compared to both patients with SAP (602.2 +/- 62.2 vs. 510.8 +/- 50.3,p < 0.001) and control subjects (368 +/- 79.6, p < 0.001). The difference in anti-oxLDL levels between patients with SAP and the controls was also statistically significant. OxLDL levels were not correlated with age in any of the groups studied. Triglycerides, LDL-cholesterol and total cholesterol were elevated in patients with UAP as opposed to patients with SAP and the control subjects, while HDL levels were elevated in the control subjects when compared to patients with SAP and UAP. Homocysteine levels were elevated in patients suffering from UAP and SAP when compared to healthy subjects. Patients with UAP or SAP did not differ on homocysteine levels. Our findings demonstrate the presence of oxLDL in vivo, its strong association with coronary artery disease as well as with the severity of the clinical presentation.

Influence of age and sex on levels of anti-oxidized LDL antibodies and anti-LDL immune complexes in the general population

Most studies of antibodies to oxidized LDL have been undertaken in patients with different diseases and cardiovascular risk factors. However, very few studies have researched the distribution and determining factors of antibodies to oxidized LDL in the general population. A total of 1,354 persons (817 females and 537 males) aged 5-65 years were included in this study. They were selected randomly from the population census of Málaga, in southern Spain. The females had lower levels of total cholesterol and triglycerides and higher levels of HDL-cholesterol and a very significant increase (P < 0.0001) in levels of anti-oxidized LDL [low density lipoprotein modified by malondialdehyde (MDA-LDL)] antibodies but no difference in levels of immune complexes consisting of LDL and IgG antibodies (anti-LDL immune complex). Younger persons (16-35 years) had higher levels of anti-oxidized LDL (MDA-LDL) antibodies than persons older than 35 years (P = 0.05). Levels of immune complexes were significantly higher (P = 0.05) in persons aged 5-15 years than in persons older than 40 years. A very weak association was found between levels of anti-oxidized LDL (MDA-LDL) antibodies and anti-LDL immune complexes. The higher prevalence of anti-oxidized LDL (MDA-LDL) antibodies in females and young persons is in agreement with studies that found an inverse association between atherosclerosis and the level of these antibodies.