Epithelial barrier dysfunction, type 2 immune response, and the development of chronic inflammatory diseases

The prevalence of many chronic noncommunicable diseases has been steadily rising over the past six decades. During this time, humans have been increasingly exposed to substances toxic for epithelial cells, including air pollutants, laundry and dishwashers, household chemicals, toothpaste, food additives, microplastics, and nanoparticles, introduced into our daily lives as part of industrialization, urbanization, and modernization. These substances disrupt the epithelial barriers and lead to microbial dysbiosis and cause immune response to allergens, opportunistic pathogens, bacterial toxins, and autoantigens followed by chronic inflammation due to epigenetic mechanisms. Recent evidence from studies on the mechanisms of epithelial barrier damage has demonstrated that even trace amounts of toxic substances can damage epithelial barriers and induce tissue inflammation. Further research in this field is essential for our understanding of the causal substances and molecular mechanisms involved in the initiation of leaky epithelial barriers that cascade into chronic inflammatory diseases.