ORIGINAL RESEARCH article

Front. Aging Neurosci.

Sec. Parkinson’s Disease and Aging-related Movement Disorders

Volume 17 - 2025 | doi: 10.3389/fnagi.2025.1607791

Clinical Mechanisms of Repetitive Transcranial Magnetic Stimulation in Improving Constipation in Parkinson's Disease Patients through the Gut-Brain Axis

Provisionally accepted
Qianlan  BoQianlan BoYanmin  LiYanmin Li*Xiayue  WangXiayue WangHuijun  WangHuijun WangHuimiao  LiuHuimiao Liu
  • The First hospital of Hebei Medical University, Shijiazhuang, China

The final, formatted version of the article will be published soon.

Objective: This study investigates the clinical efficacy of repetitive transcranial magnetic stimulation (rTMS) in alleviating constipation in patients with Parkinson's disease (PD) via the gut-brain axis. Methods: Fifty-eight PD patients with constipation, admitted from May 2023 to December 2024, were randomly assigned to an rTMS treatment group or a sham rTMS control group (29 patients each). Chronic constipation severity was assessed using the Chronic Constipation Severity Score (CSS) before and 14 days after treatment. Additional measures included weekly spontaneous bowel movements (SBM), complete spontaneous bowel movements (CSBM), the Bristol Stool Scale (BSS), and serum levels of gut-brain peptides (5-HT, BDNF, VIP) and cytokines (IL-6, IFN-γ, TNF-α, IL-4, IL-10). Results: Baseline characteristics, including CSS scores, were similar between groups (P > 0.05). After 14 days, the study group exhibited significantly lower CSS scores compared to the control group (e.g., CSS post-treatment: study group 4.03 ± 1.01 vs. control group 6.23 ± 1.03, P < 0.001). Both groups showed increased SBM and CSBM frequencies; however, the study group demonstrated significantly higher counts (e.g., CSBM post-treatment: study group 4.67 ± 0.04 vs. control group 4.16 ± 0.06, P < 0.001). BSS scores improved in both groups, with the study group achieving significantly higher scores (P < 0.05). Post-treatment, the study group had significantly higher serum 5-HT (P < 0.001) and BDNF (P = 0.001) levels, and lower VIP levels (P = 0.041) compared to the control group. Cytokine analysis revealed significantly lower pro-inflammatory IL-6 (P < 0.001), IFN-γ (P = 0.034), TNF-α (P < 0.001) and higher anti-inflammatory IL-4 (P < 0.001), IL-10 (P < 0.001) levels in the study group, with corresponding Cohen's d values indicating medium to very large effect sizes. Conclusion: rTMS effectively improves constipation symptoms in PD patients over a 14-day period. These benefits are associated with favorable modulations of gut-brain peptides and cytokine profiles, suggesting a therapeutic mechanism involving the gut-brain axis. However, direct causality and the long-term effects require further investigation.

Keywords: repetitive transcranial magnetic stimulation, gut-brain axis, Parkinson's disease, Constipation, non-motor symptoms, Neuromodulation

Received: 08 Apr 2025; Accepted: 15 Jul 2025.

Copyright: © 2025 Bo, Li, Wang, Wang and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Yanmin Li, The First hospital of Hebei Medical University, Shijiazhuang, China

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.