Changes Of Heme Oxygenase-1 Expression In Circulating Monocytes And Lymphocytes From Patients With Coronary Heart Disease

Backgroud: Heme oxygenase(HO) is a rate-limiting enzyme ofendogenetic carbon monoxide (CO) that degrades heme into carbon monoxide, bilirubin and iron. These products have important physiological effects: bilirubin is a potent antioxidant which can act against ischemia/reperfusion injury, there is a negative correlation between the content of bilirubin and the incidence of coronary heart disease~[1,2]. Carbon monoxide was regarded as a poisonous gas previously. However, recent studies have shown carbon monoxide is a factor acting as a potent vasodilator within its physiological concentration. In addition, CO inhibits platelet aggregation and proliferation of vascular smooth muscle cells, inhibits endothelial cell apoptosis, and stimulates angiogenesis for regulation of cardiovascular function. There are three reported HO isoforms, HO-1, HO-2 and HO-3. HO-1 is inducible and ubiquitously expressed, particularly after induction by oxidative stress, but HO-2 and HO-3 are constitutively expressed in cells. HO-1 plays an important role in the conservancy of the cardiovascular system ~[3]: protecting cardiocytes and endothelial cell by antioxidant, blocking the growth and proliferation of vascular smooth muscle cells (VSMC), maintaining tissue homeostasis and inhibiting endothelial cell apoptosis, lightening vascular bad remodeling after injury, restraining directly cardiocytes hypertrophy.Objective: To investigate the expression level of HO-1 in patients with coronary heart disease(CHD); To find out the association betweem HO-1 expression and clinical types of CHD; To observe the relation betweem HO-1 expression level and coronary lesions and angiographic morphology.Methods: 110 consecutive patients with CHD were diagnosed by coronaryangiography. Each one had greater than or equal to 50% stenoses of greater than or equal to one coronary artery. The patients were divided into groups by different ways.Firstly, they were divided clinically into 3 groups: Acute myocardial infarction group (AMI), 40 cases; Unstable angina pectoris group (UAP), 40 cases; Stable angina pectoris group (AP), 30 cases. Secondly, the patients were split into single vessel group (SV, 38 cases), double-vessel group (DV, 44 cases) and multi-vessel group (MV, 28 cases) according to quantity of coronary lesions according to their angiographic results. Thirdly, according to their angiographic morphology of coronary lesions' ' , 110 patients were categorized into type I group, 36 cases; type II group, 48 cases; and type III group, 26 cases. Another 30 cases with normal coronary artery diagnosed by angiography were selected as control group.Lymphocytes and monocytes were isolated by lymphocyte separation medium. HE staining was done to make sure that the cells separated are lymphocytes and monocytes. The levels of HO-1 protein expression in monocyte and lymphocyte coming from the subjects were tested by immunohistochemistry and western blot. Computer picture analyzing system was also used to measure the levels of HO-1 protein expression. We used Philips Type 5000 digital vasography machine to fulfill our coronary angiography, using Judkins method, results were analyzed by at least two experienced cardiologists. Data were analyzed using professional statistical software (SPSS, version 11.0). P=$ 0.05 was taken as significant. All reported P values were two-sided.Results: The positive immunohistochemical staining of HO-1 proteins wasshown as brown signals in the cytoplasm. There was little HO-1 expression in the cytoplasm in the control group. The levels of HO-1 protein expression in patients with coronary heart disease were significantly higher than those without coronary heart disease (PO.01). There was a maximum expression of HO-1 in patients with AMI, and a minimum expression in AP group. Expression of HO-1 in patients with Type III was much higher than Type II and Type I (PO.01) with a minimum expression in Type I. Patients with multi-vessel lesions also showed a higher expression of HO-1 than double-vessel group and single-vessel group (PO.01), and single-vessel group only expressed a little HO-1 protein.We measured expression of HO-1 by Western blot and Immunohistochemistry and compared the results. Expression of HO-1 increased significantly as it progressed from the AP to the UAP and to the AMI team; from the Type I to the Type II and to the Type III team; from the SV to the DV and to the MV team. The expression of HO-1 was low in the controls, slightly increased in group with AP, Type I or SV, markedly increased in group with UAP, Type II or DV, and further increased in group with AMI , Type III or MV. This pattern of change was similar to that of immunohistochemistry.Conclusions: There is a higher expression of HO-1 in patients with CHD; Thelevels of HO-1 protein are associated with severity of CHD, the more serious the CHD is, the higher expression of HO-1 protein; The more coronary lesions, the higher expression of HO-1; There is a relation betweem HO-1 expression level and angiographic morphology of coronary lesions. HO-1 expression in type III is higher than type II and type I.