Chen Xiao-Fei, Guo Yun, Lu Xing-Qi, Qi Le, Xu Kuang-Hui, Chen Yong, Li Guo-Xiong, Ding Jian-Ping, Li Jie
Department of Radiology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
Department of Gastroenterology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
Front Neurosci. 2021 Sep 3;15:721822. doi: 10.3389/fnins.2021.721822. eCollection 2021.
The appearance and aggravation of diarrhea-predominant irritable bowel syndrome (IBS-D) have proven to be closely related to psychosocial factors. We aimed to measure altered spontaneous brain activity and functional connectivity (FC) in patients with IBS-D using resting-state functional magnetic resonance imaging (RS-fMRI) and to analyze the relationship between these parameters and emotional symptoms.
Thirty-six adult IBS-D patients and thirty-six demographic-matched healthy controls (HCs) underwent RS-fMRI scans. After processing RS-fMRI data, the values of the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) of the two groups were compared. The abnormal regions were selected as the regions of interest to compare whole-brain seed-based FC between the groups. The relationships between RS-fMRI data and mood and gastrointestinal symptoms were analyzed using correlation and mediation analyses.
Compared with HCs, IBS-D patients showed increased ALFF in the right cerebellum posterior lobe, the right lingual gyrus/calcarine, the right postcentral gyrus, the right superior frontal gyrus (SFG), and middle frontal gyrus (MFG), with decreased ALFF in the right inferior parietal lobule, the right striatum, the right anterior cingulated cortex, the right insula, the right hippocampus, the right thalamus, the right midbrain, and the left precuneus. IBS-D patients showed increased ReHo in the bilateral lingual gyrus/calcarine, the bilateral SFG, the right MFG, and the right postcentral gyrus, with decreased ReHo in the orbital part of the left inferior frontal gyrus and the right supplementary motor area. Patients showed enhanced FC between the left precuneus and the bilateral orbitofrontal cortex (OFC). There was a positive correlation between increased ALFF values in the right midbrain and anxiety-depression symptoms in IBS-D patients, and the mediating effect of gastrointestinal symptoms indirectly caused this correlation.
IBS-D patients had dysregulated spontaneous activity and FC in regions related to pain regulation and emotional arousal involved in prefrontal-limbic-midbrain circuit and somatosensory processing. The development of mood disorders in IBS-D patients may be partly related to the dysfunction of components in the dopamine pathway (especially the midbrain, OFC) due to visceral pain.
已证实腹泻型肠易激综合征（IBS - D）的出现及加重与心理社会因素密切相关。我们旨在使用静息态功能磁共振成像（RS - fMRI）测量IBS - D患者大脑自发活动和功能连接（FC）的改变，并分析这些参数与情绪症状之间的关系。
36例成年IBS - D患者和36例人口统计学匹配的健康对照者（HCs）接受了RS - fMRI扫描。对RS - fMRI数据进行处理后，比较两组的低频振幅（ALFF）和局部一致性（ReHo）值。选择异常区域作为感兴趣区，比较两组间基于全脑种子点的FC。使用相关性和中介分析来分析RS - fMRI数据与情绪及胃肠道症状之间的关系。
与HCs相比，IBS - D患者右侧小脑后叶、右侧舌回/距状裂、右侧中央后回、右侧额上回（SFG）和额中回（MFG）的ALFF增加，而右侧顶下小叶、右侧纹状体、右侧前扣带回皮质、右侧岛叶、右侧海马、右侧丘脑、右侧中脑和左侧楔前叶的ALFF降低。IBS - D患者双侧舌回/距状裂、双侧SFG、右侧MFG和右侧中央后回的ReHo增加，而左侧额下回眶部和右侧辅助运动区的ReHo降低。患者左侧楔前叶与双侧眶额皮质（OFC）之间的FC增强。IBS - D患者右侧中脑ALFF值增加与焦虑抑郁症状呈正相关，胃肠道症状的中介作用间接导致了这种相关性。
IBS - D患者在与疼痛调节和情绪唤起相关的区域存在自发活动和FC失调，这些区域涉及前额叶 - 边缘系统 - 中脑回路和体感处理。IBS - D患者情绪障碍的发生可能部分与内脏痛导致的多巴胺通路（尤其是中脑、OFC）成分功能障碍有关。
