Neuropeptide innervation and neuroendocrine cells in allergic rhinitis and chronic hypertrophic rhinitis

Background: The neuropeptides and neuroendocrine cells are proven to exist in the human nasal mucosa. However, the pathophysiological and neuroimmunological roles of regulatory peptides in human nasal diseases require further investigation. Objectives: To investigate and compare the functional morphology and quantify the tissue concentration of regulatory peptides in the nasal mucosas of normal, allergic rhinitis (AR) and chronic hypertrophic rhinitis (CHR) subjects. Methods: Human inferior turbinate mucosa specimens from 28 patients with AR, 25 patients with CHR and 15 patients without any nasal diseases were investigated. Using immunohistochemistry and radioimmunoassays, we detected the presence, distribution and concentrations of various neuropeptides (vasoactive intestinal peptides [VIP], neuropeptide Y [NPY], substance P [SP], calcitonin gene-related peptides [CGRP]) and general neuroendocrine markers (neuronee- specific enolase, chromogranin A and somatostatin). Quantitative analysis of the stained fibres and cells were performed using a graphic AutoCAD program. Results: The presence and distribution of NPY, CGRP, and SP nerve fibres and neuroendocrine cells were similar among the three subject groups. AR subjects had significantly higher VIP and SP tissue concentrations. VIP fibres had highest density in AR subjects and these fibers predominantly innervated vessels. In CHR, VIP fibres primarily innervated glands. Conclusions: VIP and SP may play an important neuroimmunological role in the pathogenesis of AR. VIP may lead to the hypertrophic changes of submucosal glands in the pathogenesis of CHR.