Decrease of ornithine decarboxylase activity in premalignant gastric mucosa and regression of small intestinal metaplasia in patients supplemented with high doses of vitamin E.

The effect of high doses of vitamin E (Vit.E; 400 units/ day) on ornithine decarboxylase (ODC) activity and regression of small intestinal metaplasia (SIM) was studied in a 1-year double-blind intervention trial. Biochemical and morphological parameters were estimated in 14 evaluable SIM patients of 18 in the Vit.E group and in 16 of 18 intestinal metaplasia patients enrolled in control group (placebo). In the control group, there were no statistically significant changes in Vit.E content in blood plasma, ODC activity, and the rate of SIM in multiple biopsies from antrum gastric mucosa. In the Vit.E group, after 6 and 12 months of intervention, the initial content of Vit.E in blood plasma increased from 6.4 +/- 0.9 up to 17.0 +/- 1.8 and 21.2 +/- 2.3 micrograms/ml, respectively, and the initial abnormally high activity of ODC, 62.6 +/- 7.8 units, decreased by 53 and 65%, respectively. Histological analysis of multiple biopsies, taken from the gastric antrum of patients supplemented with Vit.E, revealed that in 8 of 14 patients (57%) after 6 months and in 10 of 14 patients (71%) after 12 months, no signs of SIM were observed; gastroscopic dye procedure confirmed the regression of SIM in these cases and showed the presence of only small isolated stained areas identified as SIM.

Effect of prolonged beta-carotene or DL-alpha-tocopheryl acetate supplementation on ornithine decarboxylase activity in human atrophic stomach mucosa.

The effect of beta-carotene and DL-alpha-tocopheryl acetate (alpha-TAc) on the activity of ornithine decarboxylase (ODC) in human atrophic stomach mucosa and intestinal metaplasia (IM) was studied in a double-blind intervention trial. Persons (227) with upper gastrointestinal symptoms and/or atrophic gastritis (AG) were examined. It was found that ODC activity in the biopsies of antral mucosa increased gradually from normal mucosa (7.2 +/- 1.8 units) to superficial gastritis (22.7 +/- 5.9 units) and to AG (54.2 +/- 6.9 units). Enzyme activity in cases of IM did not differ from atrophic mucosa without IM (56.1 +/- 8.0 versus 51.4 +/- 5.6 units; P > 0.05). For the intervention trial, 3 groups of 20 patients with AG were studied. Patients were supplemented daily for 1 year with beta-C (20 mg; group 1), alpha-TAc (55 mg; group 2), or placebo (group 3). No significant change in ODC activity was observed in placebo-treated subjects during 1-year follow-up. During the first 3 months, beta-C supplementation resulted in about a 50% decrease in ODC activity in atrophic mucosa. A moderate decrease in ODC activity of approximately 18% was observed after 6 months supplementation with alpha-TAc. The possible role of ODC in gastric carcinogenesis is discussed.