Distribution of neuropeptides in nasal and nasopharyngeal mucosa in patients with the post nasal drip syndrome

Abstract

OBJECTIVE The post nasal drip is a very common symptom of sinusitis, allergic rhinosinusopathy, the gastroesophageal reflux disease, but there are some patients, who have a post nasal drip, sensation of a foreign body in the nasopharynx and a non-specific irritant cough with no other symptoms or signs of sinus inflammations or allergy. In the posterior rhinoscopy mucus discharge is seen. Ethiology and pathogenesis of this syndrome evolution are still unclear. The aim of the study was to identify the neuropeptide appearance and distribution in nasal and nasopharyngeal mucosa in the patients with the isolated post nasal drip syndrome and the control group, for the comparison of the data. MATERIALS AND METHODS. We investigated the biopsies of nasal and nasopharyngeal mucosa from 11 adult patients, who had the isolated post nasal drip syndrome, and from 2 control group patients without post nasal drip, by conventional light microscopy and immunohistological techniques for the protein gene product 9.5 (PGP), Neuropeptide Y (NPY), serotonin, Substance P (SP), vasoactive intestinal peptide (VIP), Calcitonin gene related peptide (CGRP) and Chromogranin A (CgA). RESULTS. The conventional light microscopy showed a very thick basal membrane, the sclerosis of small blood vessels, the hyperplasia of mucosal glands- the neurogenic inflammation, mostly in nasopharyngeal mucosa. The abundance of PGP-containing nerve fibres was found around glands, sclerotic arterioles in almost all the cases. The main neuropeptides that were found in the mucosa of the patients were VIP, NPY, CgA, mostly in the nasopharyngeal mucosa. There were differences in PGP-containing structures and the selective neuropeptide (NPY, CgA, and VIP) distribution in nasal and nasopharyngeal mucosa in comparison with the control group. CONCLUSIONS. The main histological changes in the patients with the isolated post nasal drip syndrome are a thickened basal membrane, the hyperplasia of basal cells, pronounced hyperplasia of mucosal glands, the sclerosis of small arterioles. The main neuropeptides that are found in nasal and nasopharyngeal mucosa samples are PGP 9.5, vasoactive intestinal peptide, neuropeptide Y and chromogranin in the post nasal drip syndrome group. There is an imbalance of common neuropeptide-containing innervations, mainly sympathic nerves, the precursors of neuropeptides- chromogranins in the nasopharyngeal mucosa of the patients with the post nasal drip syndrome. SP and CGRP are not the most characteristic neuropeptides in the case of the post nasal drip syndrome pathogenesis.