Serum levels of ischemia modified albumin in overweight/obese postmenopausal women: a potential biomarker of atherosclerotic burden associated with oxidative stress.

OBJECTIVE: Menopause is associated with weight gain and an increase of cardiovascular risk. The aim of the present study was to estimate serum ischemia-modified albumin (IMA) levels in postmenopausal women and evaluate their association with body mass index (BMI) and coronary artery disease (CAD). METHODS: The study included 130 non-smoker postmenopausal women aged 43-80: 40 with BMI 26-32 kg/m(2) (Group A), 60 with BMI 21-25 kg/m(2) (Group B), and 30 with documented CAD and BMI 23-29 kg/m(2) (Group C). Serum IMA, albumin, hsCRP and NT-proBNP, glucose and insulin were measured. Homeostasis assessment model score (HOMA) and Quantitative insulin sensitivity index (QUICKI) were co-estimated. RESULTS: Serum IMA and IMA to albumin ratio were significantly elevated in Group A as compared to Group B (p<0.001) and similar to those of Group C. hsCRP and NT-proBNP did not differ between Groups A and B while they were lower in comparison to Group C (p<0.001). Glucose, insulin and HOMA were elevated in Group A compared to Group B (p<0.001) while QUICKI was lower (p<0.001). In Group A, IMA was positively correlated with BMI, hsCRP, insulin, HOMA and negatively with QUICKI. In postmenopausal women, multivariable regression analysis revealed that obesity was the strongest significant determinant of circulating IMA levels (p<0.001) contributing, therefore, to the elevated serum IMA concentration. CONCLUSIONS: Postmenopausal obesity is associated with elevated serum IMA possibly due to obesity associated oxidative stress. IMA measurement could provide an assessment of atherosclerotic burden in postmenopausal women. Further clinical evaluation is under investigation.

Ischemia modified albumin, high-sensitivity c-reactive protein and natriuretic peptide in patients with coronary atherosclerosis.

BACKGROUND: Ischemia modified albumin (IMA), is a new biomarker of oxidative processes involved with coronary artery disease (CAD). We determined serum IMA, high-sensitivity C-reactive protein (hsCRP), and natriuretic peptide (NT-proBNP), and evaluated their correlation with severity of coronary atherosclerosis in patients undergoing coronary angiography (CA). Cardiac troponin T (cTnT), CK-MB mass, albumin and Total Antioxidant Status (TAS) were also evaluated. METHODS: The study included 114 patients (88 men and 30 women) aged 43-80 years with documented CAD without evidence of acute coronary syndrome undergoing CA and 163 controls (131 men and 32 women) similarly aged. RESULTS: IMA, hsCRP and NT-proBNP were higher (p<0.001 and p=0.008 for NT-proBNP) while TAS was lower (p<0.001) in patients than in controls. IMA and TAS were negatively correlated in all subjects (p<0.01). Among patients, there was no correlation between IMA and the number of diseased vessels. For CAD diagnosis the best cut-off point for IMA was 101.5 KU/L with a sensitivity and a specificity of 87.7% and a negative predictive value of 83.3%. IMA was associated with an increased risk for CAD (OR=1.23, 95% CI: 1.16-1.31; p<0.001). CONCLUSIONS: IMA determination may provide earlier information of CAD presence before hsCRP or NT-proBNP elevation, contributing to early assessment of overall patient risk.

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.