Changes in neuropeptides and neutral endopeptidase levels in children with gastritis

Gastritis which is defined as the inflammation of gastric mucosa is one of the important causes of chronic abdominal pain in childhood. Gastritis is known to develop as the result of impaired balance between protective and aggressive factors of gastric mucosa. However protection mechanisms of gastric mucosa and pathogenesis of gastritis are still not fully known. Lamina propria of gatrointestinal tract include various neuropeptides like Vasoactive intestinal peptid (VIP), Substance P (SP), Calcitonin gene-related peptide (CGRP). SP is known to play a role in inflammatory process and VIP and CGRP have anti-inflammatory effects. Neutral endopeptidase (NEP) hydolysis SP and terminates biologic effect of SP. However roles of SP, VIP and CGRP in gastric mucosa have not been investigated in detail. In this study, it was aimed to investigate the roles of neuronal and non-neuronal peptides in pathogenesis of gastritis. In our study, SP levels were found high independently from Hp in the first (neuronal SP) and second extractions (non-neuronal SP) in diseased mucosa compared to the region with a mild lesion and the lesion free mucosa. This result indicates that SP has inflammatory effects in gastric mucosa. VIP levels were found higher in healthy gastric tissue samples compared to tissue with gastritis and it was higher in the diseased mucosa compared to mucosa with mild lesion. This result may be interpreted as an indicator of anti-inflammatory effect of VIP. CGRP levels were found lower in regions with a mild lesion or diseased mucosa compared to healthy control group and it was lower in the regions with diseased mucosa compared to the regions with mild lesion. This result indicates that CGRP is one of the protective neuropeptides of gastric mucosa like VIP. A substantial diffuse NEP staining was observed in lymphoplasmocytic cells of gastritis tissue. Finding NEP positive lymphoplasmocytic cells more in inflammation sites suggests that they may have a role in initiation or deterioration of inflammation. NEP is also known to have a role in termination of the effects of SP. In our study, finding SP and NEP positive cells high in lesion sites may be interpreted as a reactive outcome. In addition, diffuse NEP staining pattern was observed to be more predominant in duodenal mucosa of patients without gastritis compared to the ones with gastritis. This is the first study which evaluates NEP levels in inflammed gastric mucosa