A COMPARATIVE STUDY OF ANTI-PHOSPHATIDYL INOSITOLE ANTIBODIES IN PATIENTS WITH MYOCARDIAL INFARCTION AND HEALTHY SUBJECTS

Immune system and inflamation is widely known to pl ay a key role in the development and progression of cardiovascular diseases. Anti-Phospholipid (aPL) an tibodies may act in the induction of immunological response leading to the development of Acute Myocar dial Infarction (AMI). Anti-Phosphatidyl Inositole (PI) Antibody (Ab) has been seen in various diseases inc luding rheumatoid arthritis, systemic lupus erythem atosus and anti-phospholipid antibody syndrome. Although t here are a few studies on the association of some autoantibodies with AMI, more epidemiological data re required to confirm their significance as indep endent risk factors in cardiovascular diseases. Moreover, th data on the relationship of autoantibodies with traditional risk factors of AMI is rare. The study of anti-PI A b in AMI may lead to understand of etiology of isch emic heart disease. This study was conducted to determin whether prevalence of anti-PI Abs, in patients wh o had AMI and to analyze their association with tradition al cardiovascular risk factors. The prevalence of a nti-PI IgG and IgM in a well characterized group of patients w ith AMI as a case group and in age and sex matched healthy subjects as control group. Sera from the ca se and the control groups were tested to evaluate t he presence of IgG and IgM isotypes to anti-PI by ELIS A method. The prevalence of anti-PI IgG and also Ig M in the case group resulted significantly higher than i n the control group with AMI (p<0.005). The finding s of this study suggest that anti-PI Abs seemed to have a rol e in AMI independent risk factors for AMI and may represent a link between autoimmunity and atheroscl erosis in patients with AMI. Comprehensive studies are recommended to explore the exact role of anti-PI Ab s in AMI.

Cardiovascular ischemia is the combined result of environmental factors and personal predispositions. Factors Science Publications AJI such as low serum adiponectin (Shojaie et al., 2009a;Elham et al., 2012) and low annexin V levels (Shojaie et al., 2009b;Youssef et al., 2013) and infectious diseases such as Mycoplasma pneumonia (Pourahmad et al., 2009) are a part of involving factors in AMI. It has been demonstrated that the immunopathological factors such as anti-beta2 glycoprotein-I Ab (Shojaie and Jahromi, 2011) and Inflammatory processes (Jahromi et al., 2010b) have an important role in the initiation and development of AMI.
The results of some studies also demonstrated an association between anti-PL Ab and Ischemic Heart Disease (IHD) (Shojaie and Jahromi, 2011;Jafarzadeh et al., 2001;Jahromi et al., 2013b;2013c). It should be noted that genetic factors as well as other traditional risk factors such as smoking, hypercholesterolemia, diabetes mellitus and hypertension may contribute to IHD development and these parameters differ among various population. Although there are a few studies on the association of some autoantibodies with AMI, more epidemiological data are required to confirm their significance as independent risk factors in cardiovascular diseases. Moreover, the data on the relationship of autoantibodies with traditional risk factors of AMI is rare.
Therefore, this case control study was conducted to assess the serum levels of Anti-Phosphatidyl Inositol (PI) Abs (IgG and IgM) in Iranian patients with AMI and healthy subjects, also to elucidate their association with traditional risk factors of the disease.

MATERIALS AND METHODS
Subjects: A total of 90 consecutive patients (aged 39-69 years) with AMI including 67 men and 23 women who were admitted to Peymanieh Hospital of Jahrom in southwest of Iran, were enrolled to this cross-sectional, case-control study.
AMI was diagnosed by the presence of two of the following criteria: (i) prolonged chest pain well-matched with AMI, (ii) typical ECG changes, (iii) rising of cardiac enzymes such as creatine kinase and lactate dehydrogenase (Antman et al., 2004).
Exclusion criteria were valvular heart disease, surgery, trauma during the prior month, cardiomyopathy, liver disease, renal failure, arthritis, malignant diseases, other inflammatory diseases (such as SLE and RA) and oral anticoagulant therapy.
A age, sex and other CAD risk factors such as Hypertension (HTN), Diabetes Mellitus (DM) and Hyper Lipidemia (HLP) matched subjects (n = 90) with similar geographic and socioeconomic backgrounds without any IHD were enrolled as a control group. All control subjects were basically healthy, with no acute or chronic illnesses and did not use any drugs. The healthy control group was recruited from blood donors attending Jahrom Blood Transfusion Center. Peripheral blood (3 cc) was collected from the two groups and the serum was separated and stored at -20°C.
The study protocol was permitted by research ethics committee of Jahrom University of Medical Sciences and informed consents were obtained from all participants before enrollment.
Historical, demographic and clinical data were obtained through a review of medical records and interviews with patients and their families. Some risk factors for MI were as follow I. Age, sex; II. History of hypertension (diagnosis confirmed when the systolic or diastolic pressures were >160 or 95 mmHg, respectively, or when the patient was using antihypertensive medication); III. Smoking, according to the criteria of the British Council for Medical Research; IV. History of heart disease (atrial fibrillation or coronary heart disease, defined as previous myocardial infarction, angina, or revascularization procedure); V. History of diabetes mellitus, according to the medical history or the use of insulin or an oral anti-diabetes drug; VI. Hypercholesterolemia, based on total cholesterol >200 mg dL −1 , LDL-cholesterol >130 mg dL −1 , or total cholesterol/HDL-cholesterol ratio >5 (Donahue et al., 1988).
Venous blood samples (3 cc) were collected on admission before starting any IV medications. Isolated sera were frozen within 2 h after collection and stored at -20°C until laboratory tests.
Serum anti-PI IgG and anti-PI IgM levels was determined by quantitative and qualitative ELISA method respectively, using commercial kit ORGENTEC Diagnostika company, REF: ORG 536, following the manufacturer instructions.
Statistical analyses were performed by SPSS (version 17; SPSS, Inc., Chicago, IL). Data were definited as mean ± SD. Continuous variables with little-to-mild skewness were summarized as mean ± SD and compared using Student's t-test. Table 1 shows age, sex, laboratory findings and frequencies of each risk factor in the study and the control groups. There was no significant difference between the two groups regarding the following variables: Age, sex, HTN, DM, LDL, HDL, total cholesterol and TG.
The association between positive anti-PI IgG and IgM tests and selected cardiovascular risk factors were assessed.  Statistically significant associations between positive anti-PI IgG and IgM tests with type hypertension were found, but there was not found any significant association between positive anti-PI IgG and IgM test with type 1 DM, type 2 DM, age, sex, LDL, HDL, TG, total cholesterol and adjusted smoking.

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There was not seen significant difference between positive anti-PI IgG test in patients with STEMI and those with NSTEMI (73.30 Vs 25.90%), (p = 0.186) and also there was not found significant difference between positive anti-PI IgM test in patients with STEMI and those with NSTEMI (74.10 Vs 26.70%), (p = 0.324).

DISCUSSION
The results of the present study indicated that positive anti-PI IgG and also IgM Abs in patients with AMI were significantly more prevalent than that observed in healthy control group. These statistically significant differences were independent of traditional risk factors and consistent with current concepts on the immune pathogenesis of atherosclerosis. However, the precise mechanisms of participation of anti-PI Abs in the pathogenesis of AMI stay to be clarified.
We could not find any research data on anti-PI Abs in AMI for comparing with the results of present study. Other aPLs have been reported to have association with CAD and AMI (Shojaie and Jahromi, 2011;Jafarzadeh et al., 2011;Greco et al., 2010;Urbanus et al., 2009;Jahromi et al., 2013b;2013c).
There was not found correlation between anti-PI Abs (IgG, IgM) and standard cardiovascular risk factors such as smoking, hypertension and diabetes which is agreement with previous studies (Shojaie and Jahromi, 2011;Jahromi et al., 2010a;2010b;2013b;2013c).
In present study there was a significant association between anti-PI IgG with HTN in the case and the control groups. The same results were found about anti-PL IgG in AMI in other studies (Yamada et al., 2010;Jahromi et al., 2013b;2013c).
As there were not significant differences between positive anti-PI Abs test in patients with STEMI and those with NSTEMI, it can be concluded that anti-PI IgG and IgM do not participate in kind of AMI (STEMI Vs NSTEMI), which is parallel with our previous studies (Jahromi et al., 2013b;2013c).

CONCLUSION
Present study may have some limitations. The patients and the healthy subjects were not matched case to case and both groups matched overally.
These results display a statistically significant association between AMI and anti-PI Abs. The results of present study is support by the data from other studies (Shojaie and Jahromi, 2011;Jafarzadeh et al., 2011;Greco et al., 2009;Urbanus et al., 2009;Jahromi et al., 2013b;2013c) support the potential important role of aPL Abs in AMI.
Comprehensive studies with larger sample size of patients and healthy subjects are recommended to explore the precise role of anti-PI IgG and IgM in IHD.

ACKNOWLEDGEMENT
This study was financed by Student Research Committee of Jahrom University of Medical Sciences. The authors are grateful to the patients and the control individuals who accepted to enter this study.