Angiotensin-Converting Enzyme Gene Insertion/Deletion Polymorphism in Patients with Pulmonary Thromboembolism

The aim of the present study is to investigate the relationship between angiotensin-converting enzyme (ACE) gene polymorphism and pulmonary embolism by comparing the frequency of ACE gene polymorphism between cases diagnosed with pulmonary embolism with that of the control group. The study included 73 patients and 73 healthy subjects as the control group. Isolated DNAs were genotyped using the polymerase chain reaction (PCR) method for the identification of the ACE insertion/deletion (I/D) polymorphism. The genotypes were determined according to the bands observed in the agarose gel electrophoresis. The frequency of ID genotype was 39.7 percent, the frequency of insertion/insertion (II) genotype was 17.8 percent, and the frequency of the deletion/deletion (DD) genotype was 42.5 percent in the patient group. In the control group, the frequency of the II genotype was 21.9 percent, the frequency of the ID genotype was 38.4 percent, and the frequency of the DD genotype was 39.7 percent. There were no statistically significant differences between the patient group and the control group in terms of the frequencies of II, ID, and DD genotypes (p> 0.05). The findings of the present study showed no association between ACE gene polymorphism and the risk of developing the pulmonary embolism. Due to the limited number of patients however, these results must be confirmed by further studies incorporating larger series of patients. *Address for correspondence: Hikmet Çoban Sakarya University Training and Research Hospital for Pulmonary Diseases, Turkey Telephone: 02644445400 E-mail: [email protected] INTRODUCTION The term venous thromboembolism (VTE) is used to express deep vein thrombosis (DVT) and pulmonary embolism (PE). Approximately ten percent of patients who suffer from deep venous thrombosis develop PE later in their life, and ten percent of these patients die (Moser 1990). Despite the improvements in diagnostic methods, pulmonary embolism continues to be associated with high morbidity and mortality rates due to delays in diagnosis. It was reported that two-thirds of cases with pulmonary thromboembolism cases are misdiagnosed, and mortality rate is as high as thirty percent in these patients, whereas the rate of mortality decreases to three percent if appropriate treatment and prophylactic therapies are instituted following accurate diagnosis (Carson et al. 1992; Goldhaber et al. 2000). Angiotensin-converting enzyme (ACE) is a dipeptidase produced in the pulmonary vascular area and it is found at various levels in several diseases of the lungs. The ACE gene plays an important role in the regulation of serum ACE levels. This observable difference in ACE between individuals is due to the polymorphisms of the ACE gene. Although polymorphisms do not cause damage to the DNA, they are predisposing factors for the disease. The most frequently studied polymorphism in the renin-angiotensin system is the ACE insertion/deletion (ID) polymorphism. This polymorphism is defined by the presence (insertion, I) or absence (deletion, D) of the 287th base pair (bp) of the 184 SELMA YESILKAYA, MUTLU KARKUCAK, HIKMET COBAN ET AL. Alu repeat sequence within intron 16 of the ACE gene located on chromosome 17 (Hooper et al. 2002). Therefore, there are three genotypes of this polymorphism: deletion/deletion (DD), insertion/insertion (II), and insertion/deletion (ID) (Della et al. 2001; Tseng et al. 2002; Plati et al. 2004). One of these three genotypes is present in diseases. The distributions of the ACE I and D alleles are almost equal in healthy people. The distribution of these genotypes in Caucasian individuals is as follows: twenty-five percent II, fifty percent ID, and twenty-five percent DD genotypes (Hessner et al. 2001). Plasma ACE activity, while being stable in one person, shows considerable differences between individuals. This observable variance in ACE levels between individuals is due in particular, to the genetic polymorphism of the ACE gene. The ID polymorphism of the ACE gene is responsible for fifty percent of the changes in serum ACE concentrations (Hessner et al. 2001). Although most studies on the pathophysiological effects of the renin-angiotensin system are limited to arterial vascular pathologies, there are accumulating studies showing that the venous system may also be affected (Chae et al. 2014; Mogielnicki et al. 2014). In addition to the disturbances in fibrinolysis, inhibition of the fibrinolytic system caused by the changes in the renin-angiotensin system can also lead to venous thromboembolism. In previous studies, research groups included only patients with DVT or VTE (DVT+PE) (Gohil et al. 2009; Kaya et al. 2013). The goal of the present study is to investigate the presence of the ACE gene polymorphism in patients with pulmonary embolism. The present study aimed to investigate whether this genetic difference creates a predisposition for the disease. MATERIAL AND METHODS The study included 73 patients with pulmonary embolism, who underwent testing and received treatment at Uludag University Medical Faculty Pulmonary Medicine Clinic, and 73 healthy volunteers as the control subjects. Particular care was given to the inclusion of patients who were diagnosed with pulmonary embolism based on the clinical findings, and laboratory and/or imaging methods, and the control group did not have any known systemic diseases. Age, gender, body mass index, comorbidities, predisposing factors, symptoms, and findings of the patients with pulmonary embolism together with the results of high-contrast thoracic tomography, lung perfusion scintigraphy, lower limb venous Doppler ultrasonography, Ddimer levels, and ECHO findings were recorded. The approval of the Uludag University Faculty of Medicine Medical Research Ethics Committee was obtained, and the subjects in the study were requested to sign an informed consent form. The patients with diabetic nephropathy, cardiomyopathy, and coronary and carotid atherosclerosis were excluded from the study. DNA Isolation and Identification of ACE