Ameliorating effects and mechanisms of transcutaneous auricular vagal nerve stimulation on abdominal pain and constipation
Xiaodan Shi, Yedong Hu, Bo Zhang, Wenna Li, Jiande DZ Chen, Fei Liu
Xiaodan Shi, Yedong Hu, Bo Zhang, Wenna Li, Jiande DZ Chen, Fei Liu
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Clinical Research and Public Health Gastroenterology

Ameliorating effects and mechanisms of transcutaneous auricular vagal nerve stimulation on abdominal pain and constipation

Abstract

Background Abdominal pain and constipation are 2 main symptoms in patients with constipation-predominant irritable bowel syndrome (IBS-C). This study aimed to investigate the effects and possible mechanisms of transcutaneous auricular vagal nerve stimulation (taVNS) in patients with IBS-C.Methods Forty-two patients with IBS-C were randomized into a 4-week sham-taVNS or taVNS treatment. The primary outcomes were complete spontaneous bowel movements per week (CSBMs/week) and visual analog scale (VAS) for abdominal pain. High-resolution anorectal manometry (HRAM) was performed to evaluate anorectal motor and sensory function. Cytokines and brain gut peptides were analyzed in blood samples. ECG was recorded for the assessment of autonomic function.Results Compared with sham-taVNS, (a) taVNS increased CSBMs/week (P = 0.001) and decreased VAS pain score (P = 0.001); (b) improved quality of life (P = 0.020) and decreased IBS symptom score (P = 0.001); (c) improved rectoanal inhibitory reflex (P = 0.014) and improved rectal sensation (P < 0.04); (d) decreased a number of proinflammatory cytokines and serotonin in circulation; and (e) enhanced vagal activity (P = 0.040). The vagal activity was weakly correlated with the CSBMs/week (r = 0.391; P = 0.010) and the VAS pain score (r = –0.347; P = 0.025).Conclusions Noninvasive taVNS improves both constipation and abdominal pain in patients with IBS-C. The improvement in IBS-C symptoms might be attributed to the integrative effects of taVNS on intestinal functions mediated via the autoimmune mechanisms.Trial registration www.chictr.org.cn, no. ChiCTR2000029644.Funding National Natural Science Foundation of China (grant no. 81970538 for FL).

Authors

Xiaodan Shi, Yedong Hu, Bo Zhang, Wenna Li, Jiande DZ Chen, Fei Liu

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Figure 9

Effects of taVNS on autonomic function and its correlation with CSBMs/week, VAS score, and plasma 5-HT level.

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Effects of taVNS on autonomic function and its correlation with CSBMs/we...
taVNS enhanced vagal activity compared with sham-taVNS, as well as compared with baseline after treatment (A). (B–D) HF was positively correlated with CSBMs/week (B) and negatively correlated with VAS score (C) and plasma 5-HT level (D). The independent sample t test was used to assess the difference between the sham-taVNS and taVNS groups. The paired Student’s t test was applied to evaluate the differences before and after the taVNS or sham-taVNS treatment. Mean ± SD is presented (versus sham-taVNS, *P < 0.05; versus baseline, ##P < 0.01). At baseline, both groups, n = 21. After treatment, taVNS group, n = 21; sham-taVNS group, n = 19. Pearson’s correlation analysis was performed to determine the correlation of the autonomic functions and CSBMs/week, VAS, and 5-HT in the taVNS group (before and after treatment, n = 42). HF, high-frequency band.