Study on CYP2E1 gene polymorphism and the relationship between methylation level of its promoter region and liver injury induced by anti-tuberculosis drugs in Mongolian tuberculosis patients in Inner Mongolia / 医学研究生学报

ABSTRACT

ObjectiveThere are few studies on whether the occurrence of anti-tuberculosis drug-induced liver injury (ADIH) is associated with the polymorphism of CYP2E gene and methylation level. This study aims to CYP2E1 gene polymorphism and the relationship between the methylation level of the promoter region and ADIH in Mongolian tuberculosis (TB) patients.Methods A total of 135 Mongolian TB patients who received standardized treatment at the Tuberculosis Research Institute of Tongliao City, Inner Mongolia from November 2015 to June 2018 were selected. According to the ADIH criteria, TB patients with liver injury were selected as the ADIH group (n=45), and TB patients without liver injury were matched as the control group based on a ratio of 1∶2 (n=90). DNA extraction and polymerase chain reaction (PCR) were performed to amplify the CYP2E1 gene to determine the CYP2E1 rs2031920 genotype, and to analyze the CYP2E1 gene polymorphism and relationship between ADIH and promoter methylation level.Results There were no significant differences in the distribution of CYP2E1 rs2031920 genotype, C1 and C2 gene frequencies between the ADIH group and the control group (P>0.05). The overall methylation level in the promoter region of CYP2E1 gene in ADIH group (0.711±0.085) was significantly lower than that of the control group (0.759±0.062). Results of Logistic regression showed that the overall methylation level in the promoter region of CYP2E1 gene was the influencing factor for the occurrence of ADIH (P<0.005). For each 0.1 unit increase of methylation level, the risk of ADIH occurrence reduced by 0.388 times, and the OR (95% CI) value was 0.388 (between 0.204 and 0.739).Conclusion The overall methylation level in the promoter region of CYP2E1 gene was reduced in Mongolian ADIH patients, but the polymorphism of CYP2E1 gene was not related to the occurrence of ADIH. These results suggested that CYP2E1 methylation could be applied to the prevention and treatment of ADIH in patients with tuberculosis.