CARDIOLOGY DEPARTMENT, GHAEM HOSPITAL, MASHHAD UNIVERSITY OF MEDICAL SCIENCES, MASHHAD, IRAN
Background-Selenium (Se) is part of the enzyme glutathione peroxidase (GSH - Px) that plays an important role in the antioxidant defense of the body. Evidence has demonstrated that populations with low intake of selenium in the diet have a 2-3 fold risk of ischemic heart disease. Positive statistically significant correlations have been found between trace element concentrations (Cu, Zn, Se) of heart tissue with physiological parameters (CO: cardiac output, EF: ejection fraction) of the heart. Increased plasma concentration of TNF-a has been found in patients with coronary artery disease. Stressed myocardium activates pro-inflammatory cytokines, such as TNF-a, which produce abnormalities in myocyte contractile function. This study was done to determine the circulating levels of Cu, Zn, Se, IL- 6, TNF - a, and erythrocyte GSH - PX activity in two groups of patients with chronic coronary artery disease (CCAD), acute myocardial infarction (AMI) and normal individuals (IHD-free).
Methods- Patients were divided into two groups: 25 with chronic CAD (CCAD) and 25 with acute myocardial infarction (AMI). The control group was 50 normal individuals that did not have any symptoms for IHD, and was gender and age-matched with the patients. Blood samples were collected during the first hours after the onset of chest pain in the acute MI group. Serum levels of Se, Cu, and Zn were determined by atomic absorption spectrometry, TNF-a and IL-6 were measured with ELISA and erythrocyte GSH-PX activity with Paglia and Valentine methods.
Results- In both groups of patients, there was a significant reduction of Se in the serum (82.36±11.31 micg/l in CCAD, 74.08±11.31 in AMI vs. 105±32.52 in control group, P-value=0.03). No statistically significant difference was found in Zn and Cu serum levels (0.98±0.22 and 112±18 in CCAD and 0.98±0.4 and 115±20 in AMI vs. 0.96±0.24 and 114±17 in control group). TNF-a titers showed a significant difference in AMI patients compared to CCAD and control groups (mean TNF-a level 37.44 pg/ml in CCAD, 914.32 pg/ml in AMI and 4.80 pg/ml in control group, P value 0.01). Serum levels of IL-6 in the two groups of CCAD and AMI patients were 3.28 15.55 and 472 207.88 pg/ml, respectively, compared to 1.28 pg/ml in the control group, P= 0.001).
Conclusion- These findings confirm the previous studies and demonstrate that patients suffering from AMI exhibit a lower plasma concentration of selenium and TNF-a and IL - 6 significantly increase during the first hours of AMI. Selenium concentration of whole blood was lower in the two patient groups (CCAD, AMI) compared to the control group GSH - PX activity has a strong inverse association with CAD.