尽管人们普遍缺乏认识，但污染因其对人类健康的不同影响而成为现代社会的一个重要关注点。环境污染物通过不同的分子机制促进多种病理。污染物会影响免疫系统和相关途径，扰乱其调节并引发促炎症反应。接触多种污染物还会导致肠道微生物群发生变化，有益微生物（例如产生短链脂肪酸的细菌）丰度减少，促炎物种过度生长。随后的肠道屏障功能障碍，加上氧化应激和炎症反应增加，在胃肠道炎症性疾病的发病机制中发挥着重要作用。此外，污染物通过多种机制促进炎症-不典型增生-癌的发生，例如氧化应激、细胞信号通路失调、细胞周期损伤和基因组不稳定。在这篇叙述性评论中，我们将描述污染物、肠道微生物群和免疫系统之间的相互作用，重点关注它们与炎症性肠病和结直肠癌的关系。了解健康向疾病转变的生物学机制可能有助于设计旨在减轻与污染物相关的疾病负担的公共卫生政策。版权所有 © 2024 Rio、Gasbarrini、Gambassi 和 Cianci。

Pollution is a critical concern of modern society for its heterogeneous effects on human health, despite a widespread lack of awareness. Environmental pollutants promote several pathologies through different molecular mechanisms. Pollutants can affect the immune system and related pathways, perturbing its regulation and triggering pro-inflammatory responses. The exposure to several pollutants also leads to alterations in gut microbiota with a decreasing abundance of beneficial microbes, such as short-chain fatty acid-producing bacteria, and an overgrowth of pro-inflammatory species. The subsequent intestinal barrier dysfunction, together with oxidative stress and increased inflammatory responses, plays a role in the pathogenesis of gastrointestinal inflammatory diseases. Moreover, pollutants encourage the inflammation-dysplasia-carcinoma sequence through various mechanisms, such as oxidative stress, dysregulation of cellular signalling pathways, cell cycle impairment and genomic instability. In this narrative review, we will describe the interplay between pollutants, gut microbiota, and the immune system, focusing on their relationship with inflammatory bowel diseases and colorectal cancer. Understanding the biological mechanisms underlying the health-to-disease transition may allow the design of public health policies aimed at reducing the burden of disease related to pollutants.Copyright © 2024 Rio, Gasbarrini, Gambassi and Cianci.