12. NEUROKININ A AND SUBSTANCE P SERUM CONCENTRATIONS CORRELATE WITH MOTILITY METRICS PREDISPOSING TO REFLUX, BUT NOT WITH ESOPHAGITIS PRESENCE IN GERD

Abstract

Abstract Background Neurokinin A (NKA) and substance P (SP) may be responsible for airway hyper-reactivity and hypersensitization. Animal studies showed an increase of their blood concentration in response to acid installation into the esophagus, suggesting the presence of neurogenic inflammation in pathogenesis of asthma and chronic cough. Association between serum concentration of these cytokines and esophageal function testing parameters in patients with gastroesophageal reflux disease (GERD) is poorly studied. Aim of the study was to assess serum concentration of neurokinin A and substance P in patients with erosive esophagitis and non-erosive form of GERD and perform correlation analysis between concentrations of these substances and data of multichannel esophageal pH-impedance (MII-pH) and high-resolution esophageal manometry (HREM). Methods The data of examination of 88 subjects (31 with erosive esophagitis (EE); 57 with non-erosive form of GERD (NERD)) served as a source for the study. Diagnosis of GERD was established per Lyon criteria. Subjects with autoimmune disorders, receiving some medications able to affect esophageal motility were not eligible. Patients underwent HREM with the use of 36-channel solid-state catheters and MII-pH with 2-pH, 6-impedandce sensors. Serum concentrations of NKA and SP were measured with ELISA kits and biochemistry analyzer. Results Acid exposure time (AET), and number of high gastroesophageal refluxes were higher in EE compared to NERD, while number of refluxes and concentrations of NKA and SP were similar. Mean, minimal and residual lower esophageal sphincter resting pressures were lower in EE compared to NERD. There was direct correlation between serum concentration of SP and number of gastroesophageal refluxes (Spearman rank R = 0.26), AET (R = 0.25), and number of refluxes lasting >5 min (R = 0.35). NKA concentration correlated directly with number of refluxes >5 min long (R = 0.28), and inversely with levels of integrated relaxation pressure (R = –0.32), and contractile front velocity (R = –0.38). Conclusions In patients with GERD, serum concentrations of Neurokinin A and Substance P do not depend on the presence of esophagitis and probably are not caused by the influence of reflux content to sensory neurons of esophageal mucosa. Established correlations may support the involvement of Neurokinin A and Substance P in pathogenesis of gastroesophageal reflux disease.