DNA hydroxymethylation modification is an important part of genome epigenetic regulation.The demethylation process from 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC) is catalyzed by Tet protein.Abnormal genomic methylation leads to the occurrence of a variety of tumors.Hydroxymethylation is modified as a kind of demethylation and is inseparable from tumorigenesis.The expression of 5-hmC changes accompanied with the development and progression of digestive system tumors,which may be associated with the TET protein family and IDH mutation.It suggested that DNA hydroxymethylation is involved in the development and progression of digestive system tumors.This paper reviews the relationship between DNA hydroxymethylation and digestive system tumors,and aims to provide a new direction for the study of Hydroxymethylation modification in digestive system tumors.

Objective: To investigate the mid-term efficacy of sacral nerve stimulation (SNS) for chronic constipation. Methods: A descriptive case series study was conducted. Patients with chronic constipation were treated in Xijing Hospital of Digestive Disease from February 2013 to December 2018 were retrospectively enrolled. The types of constipation were confirmed based on colon slow transit test, anorectal manometry and defecography in Xi'an Mayinglong Coloproctological Hospital. This study has been registered in China clinical trial registry (Registration No.: ChiCTR-ROC-16008945). Case inclusion criteria: (1) constipation was diagnosed according to Rome III criteria; (2) traditional treatment, including education, diet adjustment, laxative, biofeedback treatment, failed for at least 1 year; (3) there were no constipation-related organic diseases. After excluding neurogenic diseases, including spinal cord injury and multiple sclerosis, 21 patients were included in this study. There were 10 males and 11 females, with an average age of 50.9 (14-76) years. After the relevant examination and evaluation of patients, they underwent percutaneous nerve evaluation (PNE). If patient experienced a good response to PNE after 2 or 3 weeks (≥50%), permanent SNS implantation was performed. The improvement of clinical symptoms and quality of life between the baseline, PNE, and latest follow-up time points were compared. Improvement of clinical symptoms, including autonomic stool frequency per week, autonomic stool days per week, defecation time, visual analogue scale (VAS, lower score indicates more serious symptoms) score and Cleveland clinic constipation score (CCCS, higher score indacates more serious symptoms) criteria. The change of quality of life was scored by SF-36 questionnaires (the higher score indicates better quality of life). Results: Of 21 patients, 18 (85.7%) experienced significant improvement in symptoms with PNE, and 2 patients discontinued treatment due to their dissatisfaction. Sixteen patients (76.2%) received permanent SNS implantation, two of whom underwent bilateral PNE implantation. These patients were followed-up for mean 56 (34-72) months. The treatment was continuously effective in 13 patients (61.9%), including 3 of ODS, 1 of STC and 9 of mixed constipation. Compared with baseline, the score of constipation patients receiving permanent SNS implantation at latest follow-up was shown. The median autonomic stool frequency per week increased from 1.0 (0-7) to 7.5 (0-10) (P<0.001), the median autonomic stool days per week increased from 1.0 (0-7) d to 4.5 (0-7) d (P<0.001), the median defecation time decreased from 19.0 (8-40) minutes to 4.0 (3-31) minutes (P<0.001), the median CCCS decreased from 20.0 (13-30) to 9.0 (6-30) (P<0.001), and the median VAS score increased from 9.0 (7-40) to 80.0 (15-90) (P<0.001). The values of the 8 parts of the SF-36 questionnaire increased (all P<0.05). Conclusion: SNS implantation is safe and has obvious effects on severe constipation with stable mid-term efficacy.
China ; Constipation/therapy* ; Humans ; Middle Aged ; Quality of Life ; Retrospective Studies

Sacral neuromodulation (SNM) procedure has become a new therapy to treat chronic constipation and fecal incontinence. The surgical procedure is easy and safe. It has a small incision compared with traditional surgery and is mainly used in patients whose traditional treatment was unsuccessful. Chronic constipation is one of the most common digestive symptoms. The quality of life in patients with severe constipation has decreased greatly. Although the incidence of fecal incontinence in China is not as high as that of constipation, it also seriously affects the life of the patients, resulting in a decline in the quality of life. Although the mechanism of SNM is uncertain, with more studies conducted, understanding has become more profound, and the curative effect has been recognized. SNM can improve the symptoms and the quality of life. Many studies have reported SNM treatment. Furthermore, some trials on SNM have been conducted. It is used after colorectal resections to promote symptoms of bowel dysfunction. However, few studies reported regarding SNM for constipation and fecal incontinence in China, and knowledge regarding SNM is limited. In this article, we will mainly discuss SNM in the treatment of chronic constipation and fecal incontinence, and its research progress on the mechanism and method, surgical procedure, effectiveness, complications, postoperative contraindications, and the population who need to pay attention, in order to provide reference for the treatment of SNM in China.