Öhlmann Hanna, Koenen Laura Ricarda, Labrenz Franziska, Engler Harald, Theysohn Nina, Langhorst Jost, Elsenbruch Sigrid
Department of Medical Psychology and Medical Sociology, Ruhr University Bochum, Bochum, Germany.
Institute of Medical Psychology and Behavioral Immunobiology, Center for Translational Neuro-and Behavioral Sciences, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
Front Neurol. 2021 Oct 20;12:733035. doi: 10.3389/fneur.2021.733035. eCollection 2021.
Structural brain alterations in chronic pain conditions remain incompletely understood, especially in chronic visceral pain. Patients with chronic-inflammatory or functional bowel disorders experience recurring abdominal pain in concert with other gastrointestinal symptoms, such as altered bowel habits, which are often exacerbated by stress. Despite growing interest in the gut-brain axis and its underlying neural mechanisms in health and disease, abnormal brain morphology and possible associations with visceral symptom severity and chronic stress remain unclear. We accomplished parallelized whole-brain voxel-based morphometry analyses in two patient cohorts with chronic visceral pain, i.e., ulcerative colitis in remission and irritable bowel syndrome, and healthy individuals. In addition to analyzing changes in gray matter volume (GMV) in each patient cohort vs. age-matched healthy controls using analysis of covariance (ANCOVA), multiple regression analyses were conducted to assess correlations between GMV and symptom severity and chronic stress, respectively. ANCOVA revealed reduced GMV in frontal cortex and anterior insula in ulcerative colitis compared to healthy controls, suggesting alterations in the central autonomic and salience networks, which could however not be confirmed in supplemental analyses which rigorously accounted for group differences in the distribution of sex. In irritable bowel syndrome, more widespread differences from healthy controls were observed, comprising both decreased and increased GMV within the sensorimotor, central executive and default mode networks. Associations between visceral symptoms and GMV within frontal regions were altered in both patient groups, supporting a role of the central executive network across visceral pain conditions. Correlations with chronic stress, on the other hand, were only found for irritable bowel syndrome, encompassing numerous brain regions and networks. Together, these findings complement and expand existing brain imaging evidence in chronic visceral pain, supporting partly distinct alterations in brain morphology in patients with chronic-inflammatory and functional bowel disorders despite considerable overlap in symptoms and comorbidities. First evidence pointing to correlations with chronic stress in irritable bowel syndrome inspires future translational studies to elucidate the mechanisms underlying the interconnections of stress, visceral pain and neural mechanisms of the gut-brain axis.
慢性疼痛状况下大脑结构的改变仍未被完全理解，尤其是在慢性内脏痛方面。患有慢性炎症性或功能性肠病的患者会反复出现腹痛，并伴有其他胃肠道症状，如排便习惯改变，这些症状常因压力而加重。尽管人们对肠-脑轴及其在健康和疾病中的潜在神经机制越来越感兴趣，但大脑形态异常以及与内脏症状严重程度和慢性应激的可能关联仍不清楚。我们对两个慢性内脏痛患者队列（即缓解期溃疡性结肠炎和肠易激综合征患者）以及健康个体进行了基于体素的全脑形态计量学平行分析。除了使用协方差分析（ANCOVA）分析每个患者队列与年龄匹配的健康对照相比灰质体积（GMV）的变化外，还进行了多元回归分析，以分别评估GMV与症状严重程度和慢性应激之间的相关性。ANCOVA显示，与健康对照相比，溃疡性结肠炎患者额叶皮质和前岛叶的GMV减少，这表明中枢自主神经和突显网络发生了改变，然而在严格考虑性别分布组间差异的补充分析中未能得到证实。在肠易激综合征中，观察到与健康对照更广泛的差异，包括感觉运动、中央执行和默认模式网络内GMV的减少和增加。两个患者组额叶区域内内脏症状与GMV之间的关联均发生了改变，支持中央执行网络在各种内脏痛状况中的作用。另一方面，仅在肠易激综合征中发现了与慢性应激的相关性，涉及多个脑区和网络。总之，这些发现补充并扩展了慢性内脏痛现有的脑成像证据，支持慢性炎症性和功能性肠病患者尽管在症状和合并症方面有相当大的重叠，但大脑形态存在部分不同的改变。肠易激综合征与慢性应激相关性的首个证据激发了未来的转化研究，以阐明应激、内脏痛和肠-脑轴神经机制之间相互联系的潜在机制。
