AIM:To assess whether glutamate plays a similar role to glutamine in preserving gut wall integrity.METHODS:The effects of glutamine and glutamate on induced hyperpermeability in intestinal cell lines were studied.Para...AIM:To assess whether glutamate plays a similar role to glutamine in preserving gut wall integrity.METHODS:The effects of glutamine and glutamate on induced hyperpermeability in intestinal cell lines were studied.Paracellular hyperpermeability was induced in Caco2.BBE and HT-29CL.19A cell lines by adding phorbol-12,13-dibutyrate(PDB) apically,after which the effects of glutamine and glutamate on horseradish peroxidase(HRP) diffusion were studied.An inhibitor of glutamate transport(L-trans-pyrrolidine-2,4-dicarboxylic acid:trans-PDC) and an irreversible blocker(acivicin) of the extracellular glutamine to glutamate converting enzyme,γ-glutamyltransferase,were used.RESULTS:Apical to basolateral HRP flux increased significantly compared to controls not exposed to PDB (n=30,P<0.001).Glutamine application reduced hyperpermeability by 19%and 39%in the respective cell lines.Glutamate application reduced hyperpermeability by 30%and 20%,respectively.Incubation of HT29CL.19A cells with acivicin and subsequent PDB and glutamine addition increased permeability levels.Incubation of Caco2.BBE cells with trans-PDC followed by PDB and glutamate addition also resulted in high permeability levels.CONCLUSION:Apical glutamate-similar to glutaminecan decrease induced paracellular hyperpermeability.Extracellular conversion of glutamine to glutamate and subsequent uptake of glutamate could be a pivotal step in the mechanism underlying the protective effect of glutamine.展开更多
基金Supported by VU University Medical Center,Amsterdam,The Netherlands
文摘AIM:To assess whether glutamate plays a similar role to glutamine in preserving gut wall integrity.METHODS:The effects of glutamine and glutamate on induced hyperpermeability in intestinal cell lines were studied.Paracellular hyperpermeability was induced in Caco2.BBE and HT-29CL.19A cell lines by adding phorbol-12,13-dibutyrate(PDB) apically,after which the effects of glutamine and glutamate on horseradish peroxidase(HRP) diffusion were studied.An inhibitor of glutamate transport(L-trans-pyrrolidine-2,4-dicarboxylic acid:trans-PDC) and an irreversible blocker(acivicin) of the extracellular glutamine to glutamate converting enzyme,γ-glutamyltransferase,were used.RESULTS:Apical to basolateral HRP flux increased significantly compared to controls not exposed to PDB (n=30,P<0.001).Glutamine application reduced hyperpermeability by 19%and 39%in the respective cell lines.Glutamate application reduced hyperpermeability by 30%and 20%,respectively.Incubation of HT29CL.19A cells with acivicin and subsequent PDB and glutamine addition increased permeability levels.Incubation of Caco2.BBE cells with trans-PDC followed by PDB and glutamate addition also resulted in high permeability levels.CONCLUSION:Apical glutamate-similar to glutaminecan decrease induced paracellular hyperpermeability.Extracellular conversion of glutamine to glutamate and subsequent uptake of glutamate could be a pivotal step in the mechanism underlying the protective effect of glutamine.
