Avaliação das enzimas ectonucleotidases e do estresse oxidativo em pacientes com e sem elevação do segmento ST no eletrocardiograma

Abstract

Acute myocardial infarction (AMI) is one of the major public health problems worldwide. A blockage of the coronary arteries occurs in AMI, which that may be total with ST segment elevation (STEMI) or partial with no ST segment elevation (NSTEMI) depending on the size of the thrombus. This thrombus blocks the blood flow and consequent there is a lack of oxygen to the myocardium increasing the formation of reactive oxygen species (ROS) which cause oxidative damage to macromolecules and various cellular structures changing the functioning of vital organs. Also, in this process we see the release of adenine nucleotides ATP and ADP, which are hydrolyzed by ectonucleotidase enzymes and regulate the thrombus formation. In this context, this study aimed to evaluate the activity of ectonucleotidase enzymes in platelets of STEMI and NSTEMI patients and controls as well as to check the oxidative profile through markers of oxidative stress and antioxidant defenses. Blood samples were collected from 100 patients with AMI treated at the University Hospital of Santa Maria (HUSM). These patients were divided into two groups characterized by electrocardiogram: STEMI and NSTEMI. The control group consisted of 74 healthy subjects. Results demonstrated that STEMI patients had higher activity of ectonucleotidase enzymes and adenosine deaminase (ADA) as well as higher troponin levels when compared with NSTEMI patients. Regarding the oxidative profile, we observed an increase in protein carbonyl, thiobarbituric acid (TBARS) levels and ischemia modified albumin (IMA) in STEMI patients. The same occurred in the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). However, the levels of vitamin C were lower in STEMI patients compared with the control group and NSTEMI patients, suggesting less protection for these patients or exhaustion after fulfilling the defense function against ROS. In the NSTEMI patients, the statistical analysis of oxidative stress markers revealed increased levels of IMA as well as SOD and TBARS compared to the control group. According to our results we suggest that the analysis of the ectonucleotidase activities could be used as a new marker for differentiating STEMI and NSTEMI patients. Moreover, the markers of oxidative stress (IMA, protein carbonyl and TBARS) and enzymatic defenses (CAT and SOD) do not distinguish the condition of STEMI NSTEMI.