Polyamines and ornithine decarboxylase activity in intestinal metaplasia and dysplasia of gastric mucosa

Purpose: In a rural area of Northern-Eastern Italy, where we operate, there is a higher incidence for gastric cancer than in other sides of our country. Epithelial dysplasia and intestinal metaplasia are considered pre-neoplastic lesions of gastric mucosa. Polyamines (PA)—Spermine (SPM), Spermidine (SPD), Putrescine (PUT)—as well as Ornithine decarboxylase (ODC), their rate limiting enzyme, have been suggested to be sensitive markers of cell proliferation because closely linked to DNA regulation, RNA, protein synthesis and membrane stability. Thus we have determined both PA and ODC activity in gastric epithelial metaplasia and dysplasia. Methods: Selected informed patients were admitted to the study, during their endoscopical follow-up, since either gastric metaplasia (n 5 10) or dysplasia (n 5 10) had been within 6 months ascertained by means of histological examination. Two experienced endoscopists obtained the biopsy specimens from the appropriate sites. Ten subjects with suspected gastric disease but unconfirmed were used as controls. From the obtained tissues both histological pattern verification and PA-ODC assessments were performed. Four biopsy specimens were frozen with liquid nitrogen and stored at 280°C up to the determinations. PA (SPD, SPM, PUT) were determined with HPLC and ODC with radiometric technique according to Stefanelli (1986). Wilcoxon’s test has been used for statistical analysis. PA values are expressed as nmol/g protein; ODC acitivity as pmol 14CO2/ hr/mg protein. Results: The obtained values, expressed as means and ranges, are reported in the table. The bold typed values are significantly different (p , 0.05) vs. the group of patients with intestinal metaplasia; the underlined values are significantly different (p , 0.05) vs. controls. Conclusions: ODC activity as well as PA have been suggested to be elevated in different gastrointestinal cancers. Our results have evidenced a significant increase of both ODC and PA, mostly for PUT, in those patients affected by gastric dysplasia. This pattern would confirm the key role of such markers in biologic changes of gastric mucosa displaying the high risk of neoplastic transformatio