Clinical and experimental studies showed that the inflammatory reaction resulting from ischemia and reperfusion is associated with the induction of cytokines such as tumor necrosis factor (TNF)-alpha,
interleukin (IL)-1b, and IL-6, which are thought to act in a cascade fashion (Gwechenberger et al .,1999). Early investigations suggested that PMNs modulate coronary endothelial cell injury, myocardial necrosis,and
reductions in coronary blood flow that occur after myocardial ischemia and reperfusion (MI/R). Clinical investigations have provided some preliminary evidence that PMNs and endothelial cell adhesion molecules are activated in the coronary circulation under conditions of unstable angina, coronary vasospasm,and acute myocardial infarction in humans, and the involvement of CAMs in ischemic-reperfused myocardial tissue participates in the firm adhesion of activated PMNs to cardiac myocytes via interactions with CAMs, resulting in myocyte injury and necrosis (Palazzo et al., 1998). Sixty four patients were included in this study, their age range (40-73) year, 44 from them were lived patients who they admitted to cardiac care unite in AL-Kadhumyia Teaching Hospital in Baghdad from 1st of April 2005 to 30th September 2005 and diagnosed clinically as either MI or unstable angina, and the rest of patients (i.e.20) were dead patients who were
died from heart attack results from ischemia depending on medicolegal diagnosis. Regarding to control groups, three dead individuals used as a control group for dead patients who they appeared healthy before death, and eighteen aged and sex matched apparently healthy individuals were also included in this study as a control group to the lived patients. Autopsies of patients and controls were taken and then fixed with
formalin, and then embedded in paraffin.They were cut into sections and then the sections were fixed on positively charge slides in order to study the expression of cell adhesion molecules (CAMs) and the local expression of the cytokines (TNF-alpha, INF-gamma, IL-10). Sera were taken from lived patients at three time: at admission, after 24hrs and at discharge, and also were taken from apparently healthy individuals (control group), then aliquted and stored in freezing until using for estimation of systemic levels of cytokines (TNF-alpha, IL-10), C-reactive protein (CRP), and anticholesterol autoantibodies.The dead patients in our study were classified in to four groups according to the histomorphological changes that occurred within
myocardial tissue during ischemia/reperfusion injury, they were: no changes group (n=4), early ischemic changes group (n=6), advanced infarction group (n= 4), and old infarction group (n=6). While lived patients were classified clinically as myocardial infarction (MI) and unstable angina. The expression of cell adhesion molecules was studied by the immunohistochemistry technique which was suitable for tissue fixed by formalin and paraffin embedded in the cases of intracellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) by the immuno-alkaline phosphetase immnostaining technique which amplified by avidine- biotin complex interaction . Cytokines expression was studied using in situ hybridization technique using long chain of cDNA probes specific for mRNA of interleukin-10 (IL-10), interferon gamma (INF-gamma), and tumor necrosing factor-alpha (TNF-alpha). We used an enzyme linked immunosorbant assay (ELISA) technique for the estimation of the systemic levels of cytokines(TNF-alpha,IL-10) and the levels of anti-cholesterol autoantibodies(IgM, IgG), whereas, latex agglutination test was used for Creactive
protein (CRP). The Results of this study showed that the average age of lived patients with myocardial infarction (MI) was 59 years and 45 years with unstable angina while the average age of the dead patients was 65 years, and 55 (86%) of our patients were male and 9(14%) were female. Serological tests showed that serum levels of CRP were elevated in patients with ischemic heart disease, and the anti-cholesterol auto-antibodies were present in healthy individuals but elevated in patients with ischemic heart disease especially, the IgG auto-antibodies. The systemic levels of TNF-alpha and IL-10 were elevated in sera of ischemic heart disease patients and reach its peak within few hours after infarction (i.e. at the time of the admission). Immunohistochemical study showed that the expression of CAMs reach its peak in early stages and their expression become very low in old stages, and the main cells that expressed cell adhesion molecules (CAMs) were the endothelial cells and the survived myocytes mainly around the infracted area.
In situ hybridization detection of the cytokine’s mRNA showed that the high expression of TNF-alpha mRNA was seen in early stages of infarction while very low expression in old infarction and the highest expression was seen in advanced infarction, the main cells that expressed TNF alpha were cardiomyocytes and inflammatory cells, while INF-gamma weakly expressed in early stages but high in advanced infarction, in addition, a high level of IL-10 was seen in early stages and higher than INF-gamma, and the highest expression for IL-10 was in advanced infarction and low expression in old myocardial infarction patients group. Our results demonstrate a possible prognostic role for systemic cytokines levels especially for TNF-alpha and IL-10. Moreover, this study showed that the main player in the ischemia/reperfusion is the TNF-alpha, through its effect on the size of cellular infiltration via enhancing CAMs expression and its proinflammatory function were possibly counteracted by locally produced IL-10 which possibly mediates such effects through its negative regulation of CAM- expression. Thus, we concluded that TNF-alpha and IL-10 are important factors in tissue remodeling after ischemia/reperfusion injury especially in first few days
after infarction and the using of drugs that interfere with their function at these stages may interfere with proper remodeling and in-turn in the prognosis of the patient in addition, we suggest the possible used of IgG anticholestrol autoantibodies serum level in follow up of the individual at risk of ischemia. Our study also provides the insights into the factors that involved in pathogenesis of IHD and may provide additional targets for diagnosis, prognosis and a guide for the immunological treatment and other therapeutic intervention.