Nerve Growth Factor (NGF) Gene Analysis in Menstrual Blood of Endometriosis: DNA Methylation and mRNA Expression Levels

Menstrual blood flow is reversed through the fallopian tubes during the menstrual process and implants outside the uterus, which is the theory of pathogenesis in endometriosis sufferers. This study aims to analyze the level of DNA methylation and mRNA expression of the Nerve Growth Factor (NGF) gene in menstrual blood in endometriosis patients and analyze the correlation. The study was conducted among 20 women in each group with and without Endometriosis (controls) of reproductive age. Filter paper pads were used to collect the menstrual blood sample, while the eutopic endometrium was collected by biopsy. Following that, NGF DNA methylation analysis of menstrual blood was performed using Methylation-Specific PCR (MS-PCR) and Pyrosequencing. Additionally, the study of NGF mRNA expression was conducted by RT-qPCR. Data analysis using independent T-test or Mann-Whitney, SPSS 22, and p<0.05 was considered statistically significant. We found that the DNA of NGF in the menstrual blood of endometriosis patients was hypomethylated; conversely, its mRNA expression was increased compared to that of women without Endometriosis. There was a statistically significant difference in the level of NGF DNA methylation and the relative mRNA expression level of the NGF gene in the menstrual blood of endometriosis patients compared to women without Endometriosis (p<0.05). However, there was no correlation between DNA methylation levels and NGF mRNA expression levels in menstrual blood samples of women with Endometriosis (p>0,05). Furthermore, the increased expression of NGF mRNA in the menstrual blood of women with Endometriosis is not driven by a decrease in DNA methylation. However, hypomethylation and an increase in mRNA expression of the NGF gene in menstrual blood have the potential to be a biomarker for the early diagnosis of non-invasive Endometriosis.