肠易激综合征（IBS）及其腹泻型亚型（IBS-D）：微生物-肠-脑轴的新视角

肠易激综合征 (IBS) 是一种胃肠功能紊乱，以腹痛伴随排便或其他肠道习惯改变为特征 [1-2]。腹泻型肠易激综合征 (IBS-D) 是其最常见的亚型。目前，尚未有权威机构对其发病原因及发病机制做出明确解释，也未有明确疗效的治疗药物，只知其可能与内脏的敏感性增高、脑-肠轴的功能异常、消化道微生物的紊乱、胃肠道动力学的异常、精神心理等有关。

近年来，随着研究的深入，‘微生物-肠-脑’轴 (Microbiota-gut-brain axis, MGBA) 越发得到认可，肠道微生物通过多种渠道与中枢神经系统 (Central Nervous System, CNS) 沟通，包括神经、内分泌和免疫信号通路，微生物群可以独立产生或促进许多神经活性分子的产生，包括γ-氨基丁酸、5-羟色胺 (serotonin，5-HT) 和多巴胺等。[3] 可见针对 IBS-D 的治疗已经从针对胃肠道自身的治疗上升为针对与其相关的 ‘微生物-肠-脑’ 轴神经内分泌调节系统，从局部逐渐向整体入手，中医优势更为凸显。

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain and changes in bowel habits. The diarrhea-predominant subtype (IBS-D) is the most common form of IBS. The exact cause and mechanism of IBS-D are not well understood, but it may be related to increased visceral sensitivity, abnormal brain-gut axis function, dysbiosis of the gut microbiota, abnormal gastrointestinal motility, and psychological factors. In recent years, the microbiota-gut-brain axis (MGBA) has gained recognition in IBS-D research. The gut microbiota communicates with the central nervous system through various channels, including neural, endocrine, and immune signaling pathways. The microbiota can independently produce or promote the production of many neuroactive molecules, including gamma-aminobutyric acid, serotonin, and dopamine.

Treatment for IBS-D has shifted from targeting the gastrointestinal tract itself to targeting the MGBA neuroendocrine regulatory system, gradually moving from local to whole-body approaches, highlighting the advantages of traditional Chinese medicine.