Calcitonin Gene-Related Peptide relates with cough sensitivity in children with chronic cough

¹ Dept of Respiratory Medicine, Royal Children's Hospital, Brisbane, Queensland, Australia
² Hunter Medical Research Institute, John Hunter Hospital and University of Newcastle
³ Wellcome Research Labs, Royal Victoria Hospital, Belfast, BT 12 6BJ, N Ireland
⁴ The Queen's University of Belfast, Belfast, N Ireland

^* To whom correspondence should be addressed. E-mail: annechang{at}ausdoctors.net.

	Abstract

Airway neuropeptides, in particular calcitonin gene-related peptide (CGRP), are likely important in the pathogenesis of chronic cough. We evaluated (1) the relationship between cough sensitivity and bronchoalveolar lavage (BAL) neuropeptides, and (2) effect of reflux esophagitis (RE) on cough, cough sensitivity, and BAL neuropeptides in children not selected for cough. We hypothesised that CGRP would be increased in children with chronic cough and relate to cough sensitivity.

Capsaicin cough sensitivity was performed in children undergoing gastro-duodenal endoscopy. CGRP, substance-P (SP) and neurokinin-A (NKA) were measured in BAL obtained non-bronchoscopically. Children were defined as "coughers" if chronic cough was present.

Coughers (n=21) had significantly reduced cough sensitivity but were just as likely as non-coughers (n=19) to have RE. Median CGRP was significantly (p=0.02) higher in coughers with esophagitis (5.0, IQR 10.1) than in non-coughers with esophagitis (1.4, 4.0). CGRP significantly negatively correlated to cough sensitivity in coughers but not in non-coughers.

Elevated CGRP, but not SP or NKA, is associated with chronic cough in children only when esophagitis coexists. CGRP in BAL relates to cough sensitivity and is likely important in the pathophysiology of chronic cough.

This article has been cited by other articles:

				L.P.A. McGarvey, L. Polley, and J. MacMahon Review Series: Chronic cough: Common causes and current guidelines Chronic Respiratory Disease, November 1, 2007; 4(4): 215 - 223. [Abstract] [PDF]