Dimethyloxalyglycine stimulates the early stages of gastrointestinal repair processes through VEGF-dependent mechanisms

Dimethyloxalylglycine (DMOG) is an inhibitor of prolyl-4-hydroxylase domain enzymes. Its potential value and mechanism of actions in preventing/treating gastrointestinal injury are, however, poorly understood. We, therefore, examined the effect of DMOG on influencing gut injury and repair using a variety of in vitro and in vivo models. We performed in vitro studies utilising pro-migratory (wounded monolayer) and proliferation (using DNA quantitation) assays of human stomach (AGS) and colonic (HT29) carcinoma cells. Time course studies examined changes in hypoxia-inducible factor (HIF) and vascular endothelial growth factor (VEGF) levels, a growth factor known to be regulated via HIF. In vivo studies utilised a rat gastric (indomethacin, 20 mg/kg and 3 h restraint) damage model. DMOG stimulated migration in a dose-dependent manner, increasing migration twofold when added at 25μM (P<0.01). Additive effects were seen when DMOG was added to cells in hypoxic conditions. DMOG stimulated proliferation dose dependently, increasing proliferation threefold when added at 70 μM (P<0.01). DMOG caused upregulation of both HIF and VEGF within 4 h of administration. Addition of VEGF neutralising antibody truncated migratory and proliferative activity of DMOG by about 70%. Both oral and subcutaneous administration of DMOG decreased gastric injury without influencing intragastric pH (50% reduction in injury when 1 ml gavaged at 0.57 mM, P < 0.01). Indomethacin reduced tissue HIF and VEGF levels but this was prevented if DMOG was present. In conclusion, DMOG stimulates the early phases of gut repair and VEGF-dependent processes appear relevant. Non-peptide factors such as this may be useful to stabilise or repair gut mucosa.