Global environmental changes and the epithelial barrier hypothesis

Abstract

The global burden of noncommunicable diseases (NCD) has seen astrong increase in recent decades and attributable to the influence of environmental factors. For amultitude of diseases an association with epithelial barrier damage has been reported. This article provides an overview of the health effects of environmental pollution in the context of the epithelial barrier hypothesis of Cezmi Akdis. Additionally, exemplary mechanisms of abarrier damage are described. Finally, possible preventive and therapeutic consequences are discussed. The PubMed database was searched for the relevant topics and selected literature was reviewed. Awide variety of substances can damage the epithelial barriers of the skin, lungs and gastrointestinal tract. The rise in the prevalences of atopic diseases could (partly) be due to an increased exposure to barrier-damaging substances, such as particulate matter and laundry detergents. Apossible pathogenetic mechanism is the initiation and maintenance of an immune response by subepithelial penetration of microorganisms through damaged epithelia. Based on the epithelial barrier hypothesis new therapeutic and prevention strategies can be developed. The regulation of hazardous chemicals and the fight against environmental pollution and climate change are necessary to reduce the burden of disease.