The Role of Neuropeptides and Neurogenic Inflammation in the Isolated Postnasal Drip Syndrome. Summary of the Doctoral Thesis

Abstract

The post nasal drip as a symptom is well known in many diseases like an allergy, a sinusitis, a gastroesophageal reflux disease, but there are patients, who have excluded those conditions, but still, they have complaints abut discharges in the nasopharynx, a foreign body sensation in the nasopharynx and a dry cough. A physician can confirm mucus discharges in the nasopharynx by objective investigations of the patient. It is so called isolated postnasal drip syndrome. Usually, the patients haven’t had an improvement of the common empiric therapy with topical nasal steroids, antihistamines, and proton pump inhibitors. The etiology and pathogenesis of the isolated post nasal syndrome remain unclear; this syndrome affects patients’ life quality, so it is crucial to have more studies to elucidate the etiology and pathogenesis of this syndrome to get therapy for it. The aim of this study was to identify the role of neurohumoral innervation and neuropeptides in the nasal and nasopharyngeal mucosa of the patients suffering from isolated postnasal drip syndrome. For this purpose, we have made two groups, 20 people each. The control group was formed from voluntary patients, undergoing nasal septum surgery, without any complaints about post nasal drip and without any signs of that in the examination of the patient. The study group was formed from 20 isolated post nasal drip syndrome patients suffering from post nasal discharges, foreign body sensation, and dry cough ad least for six months, they all have had previous, unsuccessful therapy with topical nasal steroids, and antihistamines, proton pump inhibitors. All of the study group patients have had excluded allergies by the conclusion of the allergologist (negative skin prick test and IgE level in the blood), gastroesophageal reflux disease by the conclusion of the gastroenterologist and sinus inflammation performing CT scan in the axial and coronal cuts. The biopsies of nasal (the middle part of inferior nasal turbinate) and nasopharyngeal (the middle of the nasopharyngeal arch area) mucosa were taken from both groups and stained in the Morphology Laboratory of the Institute of Anatomy and Anthropology of Rīga Stradiņš University with hematoxylin and eosin and immunochemistry methods to reveal neuropeptides. The semiquantitative counting method and nonparametric statistic were used for the data analysis. The isolated post nasal syndrome patients nasal and nasopharyngeal mucosa showed a picture of nonspecific chronic inflammation with hyperplasia of epithelium and submucosal glands, infiltrations of lymphocytes in the lamina propria and thickening of the basal membrane. And there was a statistically significantly higher level of PGP 9.5, chromogranin A, VIP, NPY, CGRP, caspase, NFkB, TNFα, B-defensin. The results of our study suggest about chronic active inflammation, activation of neuroendocrine and parasympathetic nerve system, the involvement of Il-6 and Il-10 in the regulation of the inflammatory process with subsequent apoptosis and tissue remodellation in the case of isolated postnasal drip syndrome.