Gastrokine mRNA expression in gastric tissue from dogs with helicobacter colonisation but without inflammatory change during treatment

Gastrokines (GKNs) are bioactive substances secreted by gastric cells. Evidence supports functional roles for GKNs in gastric homeostasis, immune responses and tumour suppression. Down-regulation has been reported in Helicobacter pylori associated gastritis and other inflammatory gastrointestinal conditions in mice and people. The aim of this study was to evaluate GKN gene expression in dogs positive for other Helicobacter spp. both before and after treatment. Expression of Gkn-1 and Gkn-2 mRNA was studied in endoscopic biopsy samples collected from seven healthy dogs over three time-points pre- (T0) and at 1 and 18 weeks post-treatment for Helicobacter spp. colonisation (T1 & T2). The relative expression software tool (REST) was used to provide efficiency corrected expression ratios for comparisons between groups and these results were compared to a standard 2ΔΔCT methodology. Compared with T1 Gkn1 and Gkn2 mRNA expression was greater at T0 by a mean factor of 2.53 (SE = 1.83–3.54) for Gkn1 (P = 0.000) and 2.85 (SE = 2.23–3.75) for Gkn2 (P = 0.000). This difference was attenuated when comparisons were made between T0 and T2. Histopathological evidence of gastritis was not present in any Helicobacter spp. positive sample. When compared to post-eradication samples Gkn gene expression is increased in the presence of Helicobacter spp. in dogs without evidence for concurrent inflammation. Further evaluation is required to determine the relevance of this finding, however given a suspected role in gastric homeostasis, up-regulation of GKN1 and GKN2 could limit development of gastritis in Helicobacter spp. positive dogs.