Vitamin E and carotenoids in gastric biopsies: the relation to plasma concentrations in patients with and without Helicobacter pylori gastritis.

The carotenoids--lycopene and alpha- and beta-carotene-- and alpha-tocopherol were measured in plasma and in mucosal biopsies in normal subjects and in those infected with Helicobacter pylori. Two indexes of the presence of the reactive oxygen species malondialdehyde and chemiluminescence were measured in biopsies taken from adjacent sites in the same patient. In general, plasma and mucosal concentrations of all antioxidants correlated well and were of a similar order or magnitude in plasma and mucosa. There was no significant difference between the slope of the regression lines nor an overall difference in the concentrations of these antioxidants between the H. pylori-positive and control groups, indicating an absence of effect of H. pylori infection. However, a marked difference was seen in chemiluminescence and malondialdehyde concentrations in biopsies. For chemiluminescence this was highly significant. These findings confirm the presence of free radicals in the mucosa of H. pylori-infected patients and suggest therefore that the lipid-soluble antioxidants have either no role in protecting mucosal cells from free radical damage or, if they are able to scavenge these species, they are then rapidly regenerated to their original forms by redox and other processes.