Study Of Relationship Between DNA Methylation Of Estrogen Receptor-α Gene And Ischemic Stroke

ObjectiveTo investigate the DNA methylation status of ER-a gene promoter between normal and ischemic stroke patients. And to determine whether the DNA methylation status of ER-αgene promoter is related to ischemic stroke.Methods83 ischemic stroke patients and 94control subjects were selected for ER-αgene methylation research. The clinical data and risk factors should be recorded. The carotid colorized ultrasound examination results of 52 patients and magnetic resonance angiography (MRA) examination results of 57 patients were recorded. We calculate the Carotid plaque score and plaque index, and evaluate the severity of intracranial atherosclerosis. The infarct size was recorded by brain computed tomography (CT) scan or magnetic resonance imaging (MRI). The severity of neurological impairment was assessed by National Institutes of Health Stroke Scale (NIHSS) and Barthel Index (BI).Peripheral blood samples were taken for DNA extraction. The methylation status of ER-a gene promoter was measured by methylation specific PCR (MSP) method. Placental tissue was methylated by CpG methyltransferase (M.SssI) and acted as MSP reaction controls. SPSS 17.0 was used for data analysis.Results1.The age and gender of two groups were matched and comparable. There were statistical significance in hypertension, diabetes, smoking, drinking, diet, movement, waist circumference, systolic blood pressure, triglyceride and cholesterol between ischemic stroke and control groups(P<0.05).2.The ER-αgene promoter methylation frequencies of two groups were 42.2%(35/83) and 19.1%(18/94) respectively. The methylation frequency of ischemic stroke group was higher than that of the control groups (P<0.05).3.The ER-αgene promoter methylation frequencies of male and female patients in ischemic stroke group were 42.2%(19/45) and 42.1%(16/38). And the methylation frequencies of male and female subjects in control group werel7.3%(9/52) and 21.4%(9/42) respectively. There were no statistical differences between male and female subjects in both goups (P>0.05).4.The ER-a gene promoter methylation frequencies of three age subgroups in ischemic stroke group were 31.6%(12/38),45.8%(11/24) and 57.1%(12/21). And the methylation frequencies of three age subgroups in control group were 14.6%(6/41),17.5%(7/40) and 38.5%(5/13).The methylation frequency tended to increase with age in both groups, but there was no statistical significance (P>0.05).5.The carotid colorized ultrasound examination results of 52 patients were recorded. There were statistically differences in carotid intima-media thickness (CIMT), Crouse score and plaque index among full-methylation, half-methylation and non-methylation subgroups (P<0.05).6.The MRA examination results of 57 patients were recorded. The methylation frequencies of four subgroups were 40.9%(9/22),42.9%(3/7),52.4%(11/21) and 57.1%(4/7). The methylation frequency had tendency to increase with the severity of intracranial atherosclerosis, but there was no statistical significance (P>0.05).7.The methylation frequencies of three infarct size subgroups were 32.8%(19/58), 56.3%(9/16) and 77.8%(7/9). The methylation frequency increased with the infarct size (P<0.05).8.There were statistically differences in NIHSS score and Barthel index among full-methylation, half-methylation and non-methylation subgroups (P<0.05).Conclusions1.The ER-αgene promoter methylation frequency is higher in ischemic stroke patients than in control group.2.We don't observe the relationship between ER-αgene promoter methylation and gender or age.3.The ER-αgene promoter methylation status is related to the severity of carotid atherosclerosis, which may suggest an involvement of aberrant ER-αgene promoter methylation in development of ischemic stroke. The methylation frequency tends to increase with the severity of intracranial atherosclerosis, but we don't observe the relationship between them.4.The ER-αgene promoter methylation status is related to the infarct size.5.The ER-αgene promoter methylation status is related to NIHSS score and BI, which represent the severity of neurological impairment. The NIHSS score increases and the BI decreases with the increase of methylation frequency.