STUDY OF SOME CARDIAC BIOMARKERS AND OXIDATIVE STRESS MARKERS IN PATIENTS WITH ACUTE CORONARY SYNDROMES

Hassan A. Hussein BSC, Diploma, Director of Laboratories Departmen in Al-Imamain Al-Kadhimain City Hospital. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 25 November 2019 Final Accepted: 27 December 2019 Published: January 2020


Introduction:-
Coronary atherosclerosis is the cause of CHD (Davies et al., 1985, Fuster et al., 1992. Typical symptoms are chest pain and dyspnoea on exertion and are the result of reduced blood flow to myocardium. The reduction in blood flow is, in turn, caused by atherosclerotic plaques narrowing the coronary vascular lumen and thus decreasing the nutritional blood flow. In the event of sudden rupture or erosion of the plaque, a thrombogenic mass bulges into the arterial lumen, activates thrombocytes and the coagulation system. The result of this cascade of events is an occlusive thrombus which immediately reduces or discontinues the blood flow to the myocardium and leads to acute coronary syndromes (ACS) including unstable angina, acute myocardial infarction or sudden cardiac death (Davies et al., 1985, Fuster et al., 1992, and Falk et al., 1995.Plaque rupture is the main cause of fatal acute myocardial infarction and / or sudden cardiac death. These three conditions share a very similar pathology, although treatment differ (Jones et al., 2003).
Acute myocardial infarction (AMI) is one of the major causes of mortality and morbidity in the world. (Ojha et al., 2008). The most common cause of an AMI is atherosclerotic coronary artery disease (CAD) with erosion or rupture of a plaque causing transient, partial or complete arterial occlusion.
Heart cannot continue to function without adequate blood flow, and if it is severely compromised, death is inevitable. ).several risk factors for coronary heart disease have been well documented, including hypertension, hyperlipidemia,diabetes, appositive family history,smoking,obesity and inactivity.However,these factors explain only part of attributable cardiovascular disease. (Kasap et al.,2007,Pasupathi et al.,2009). Myocardial antioxidants inhibit or delay the oxidative damage to sub cellular proteins, carbohydrates, lipids and DNA. There is evidence that antioxidants can protect against free radical defense, which is responsible for reperfusion-induced damage and lipid peroxidation, and may thereby inhibit thrombosis, myocardial damage and arrhythmias during AMI. Antioxidant status is a critical tool for assessing redox status (Giselli et al., 2000). The antioxidant status or related antioxidants may play an important role in protecting the organism from free-radicals-mediated damage (Patra et al., 2001). The role that such compounds play in AMI development is important, since their presence may decrease the damage resulting from blood ROS during reperfusion.
In recent years, there has been a growing interest in studying the role of lipid peroxidation and ant ioxidant status in shock patients. There is evidence that antioxidants can protect against free radical production, which is responsible for reperfusion-induced damage and lipid peroxidation, and may thereby inhibit thrombosis, myocardial damage and arrhythmias during AMI. , the present study was undertaken to assess the serum levels of C-RP,lipid profile,Oxidative stress(MDA),and Cardiac biomarker(CKMB) in patients with ACS.

Subjects and Methods:-
The population consisted of 140 subjects divided into three groups, 39 with UA their age range (21-70), 62 with AMI their age range (39-70). The other 39 subjects age and sex matched healthy subjects were studied as controls (This group includes 39 subjects who had no history or clinical evidence of cardiac diseases or any chronic disease).All patients had been admitted to the Coronary Care Units (CCU) of Ibn alnafees Hospital and Al kindy Hospital, between July 2013 and March 2014.The clinical examination and diagnosis were performed by physician specialized in in Ibn Al-Nafees Cardiac Specialty Teaching hospital and AL-KindyTeaching hospital.
CK-MB was measured by CK-MB Kit (Fluid Stable), on photometric systems using optimized UV test according to DGKC (German Society of Clinical Chemistry) and IFCC (International Federation of Clinical Chemistry and Laboratory Medicine).
C-RP was determined in serum using commercially available ELISA and performed as recommended in leaflet with kit. (Wiesbaden.Germany) Lipid peroxides were estimated by measurement of thiobarbituric acid reactive substances in plasma by the method of Buege and Aust (1978). The pink chromogen produced by the reaction of thiobarbituric acid with malondialdehyde, a secondary product of lipid peroxidation was estimated. The absorbance of clear supernatant was measured against reference blank at 535 nm.

385
Statistical Analysis: All data were expressed as mean ± SEM. The statistical significance was evaluated by Student's ttest using Statistical Package for the Social Sciences (SPSS Cary, NC, USA) version 12.0.
As expected, the patients had significantly higher level of total cholesterol, triglyceride, LDL-cholesterol and VLDL-cholesterol levels but lower HDL-cholesterol levels than the healthy controls. The level of CK-MB and CRP in normal healthy subjects and ACS subjects was depicted in Table 1.The significantly increases in the level of CK-MB and CRP seen in ACS patients when compare to control subjects.
The concentrations of serum level MDA, are presented in Table 1.Total Lipid peroxidation MDA are significantly higher in ACS patients as compared with normal subjects.

Discussion:-
Oxidative stress has been regarded as one of the most important contributors to the progression of atherosclerosis (Halliwell, 1994). Increased lipid peroxidation is thought to be a consequence of oxidative stress, which occurs when the dynamic balance between prooxidant and antioxidant mechanism is impaired. In ischemia, the ATP is drastically reduced and is converted to hypoxanthine and then to uric acid by xanthine oxidase upon reperfusion. It has been suggested that increased lipid peroxides levels in blood of patients with AMI (Chamblee et al., 2000). We observed that increased concentrations of MDA in the circulation of total ACS patients indicating increased lipid peroxidation. Our results agreement with previous study done by ( Peking et al., 2004) who showed that plasma levels of malondiaaldehyde were significantly increased in unstable angina and acute myocardial infarction., patients when compared with control subjects. Our Data also in accordance with previous reports (Senthil et al., 2004). Changes in the concentration of plasma lipids including cholesterol are complications frequently observed in patients with MI and certainly contribute to the development of vascular disease. Cholesterol has been singled out as the primary factor in the development of atherosclerosis. HDL is regarded as one of the most important protective factors against arteriosclerosis. HDL's protective function has been attributed to its active participation in the reverse transport of cholesterol.

386
Numerous cohort studies and clinical trials have confirmed the association between a low HDL and an increased risk of coronary heart disease (Tomas et al, 2004). The concentration of LDL correlates positively whereas HDL correlates inversely to the development of coronary heart disease. Smokers have significantly higher serum cholesterol, triglyceride, and LDL levels, but HDL is lower in smokers than in non-smokers (Ambrose and Barua, 2004). Evidence suggests that oxidatively modified LDL contribute to the pathogenesis of atherosclerosis. Increased oxidative stress and the generation of the free oxygen radicals can result in modification of LDL to oxidized LDL that could lead to atherosclerotic lesions (Kharb and Singh, 2000).
Elevated levels of CK-MB have been regarded as biochemical markers of myocyte necrosis (Yilmaz et al., 2006). CK and more particularly its isoenzyme CK-MB still have a formal place in defining myocardial infarction. These enzymes normally exist in cellular compartment and leak out into the plasma during myocardial injury due to disintegration of contractile elements and sarcoplasmic reticulum (Hamm and Braunwald 2000; Kasap et al., 2007). The cardiac-specific troponins are highly sensitive and specific markers of myocardial damage and therefore cardiac troponins are the preferred markers for the diagnosis of myocardial infarction (Kasap et al., 2007;Gupta et al., 2008). In this study, increased CK-MB levels were found in patients with UA and AMI as compared to healthy controls. The mean CK-MB value was just above the reference range that adapted from the kit. This is considered reliable because peak activity of CK-MB is usually seen at 18 to 24 hours and return to baseline level by 36 to 40 hours (Puleo et al 1990).
In sixty two patients with AMI, another sample was collected from them; the mean CK-MB values of this group was significantly high and in some cases reach 9times more than the upper normal value. The CK-MB values of this group confirm the diagnosis of MI as the mode of release of CK-MB in this group suggest myocardial injury because non cardiac release of CK generally follows a flatter curve, with elevations that both rise and disappear more slowly than seen with an acute MI (Adams et al 1993).
Inflammation plays a role in the development of atherosclerosis and coronary heart disease (Lind, 2003). Elevated markers of inflammation, in particular CRP, are associated with an increased risk of future cardiovascular events in healthy subjects, in patients with stable or unstable coronary artery disease and acute myocardial infarction (Buffon et al., 2002;Zairis et al., 2002). Although the prognostic value of CRP in patients with acute coronary syndromes has not been tested in large studies, several data indicate that CRP is an important marker of risk also in this clinical setting (Tomoda et al., 2000;Nikfardjam et al., 2000). CRP has been reported to be elevated during AMI (Zebrack et al., 2002). In this study, we observed increased CRP levels in UA and AMI patients as compared to healthy controls. Moreover, CRP concentrations in each patient groups were found higher than the control group. We have observed highest concentrations of CRP in patient group : Patients with acute coronary syndrome have elevation in CRP in association with their presenting symptoms , in patients with AMI , CRP levels correlated with the presences of plaque rapture and an early study examine CRP in acute coronary syndrome found that CRP identified a subset of patients with sever unstable angina at increased risk for death and MI (Armstrong et al., 2006) and that agree with our results ,which also showed that our lived patients have elevated level of CRP in circulation, and in patients with acute MI is higher than unstable angina, (Libby et al., 1999).
Elevated CRP levels were also observed in cardiovascular, hypertension group, respectively.
In our study significant rise in MDA levels (p<0.001), a lipid peroxidation product, in our patients is indicative of elevated oxidative stress in ACS patients, whereas lipid peroxides were significantly higher in ACS patients, compared with controls. This indicates severe damage to antioxidant system, which is unable to combat oxidative stress and inflammation (Kurtul et al., 2004).
In conclusion, our study shows a significant increase in total lipid peroxidation (MDA) and cardiac biomarkers (CKMB) in the circulation of patients with Acute Coronary Syndromes.Therefore these biomarkers may be useful diagnosis of patients with ACS. 387