Is there a role for regenerative medicine in chronic rhinosinusitis with nasal polyps?

During the past five years, over than 1600 articles have been published on the subject of Chronic Rhinosinusitis with Nasal Polyps (CRSwNP). Despite this, its physiopathology remains incompletely understood. CRSwNP is an overt and reverberant inflammatory disease, which leads to the recruitment of several inflammatory cells, characterized by the presence of eosinophils, neutrophils, and mast cells.1 Although a Th2-driven response was initially thought to be the principal inflammatory mechanisms present in CRSwNP, it is now recognized that both Th1 and Th2 responses can be observed in patients with CRSwNP, depending on ethnicity or on associated diseases.1 As example, Asian patients and those with cystic fibrosis tend to present more of a Th1-skewed inflammatory profile as compared to European nasal polyps. It should be noted that the reason for such an intense inflammatory process, and the different inflammatory patterns is still poorly understood. An increased appreciation of the potential role of the nasal epithelium and its associated barrier and defensive functions may help improve our insights into CRS pathogenesis. Emerging evidence1--3 increasingly documents that nasal epithelial cells are not simply passive barriers between host interior and exterior environments, but instead play an active role in modulating and coordinating host responses to the external environment. They are capable of monitoring the environment for threats via pathogen detection, and can mount defensive responses by inducing signaling pathways, with generation of subsequent inflammation and cellular recruitment. The integrity of the epithelial barrier is determined by tight junctions (located more apically, and composed of