Apoptosis in chronic gastritis: evaluation of the gastric mucosa by DNA flow cytometry and the expression of the high molecular weight cytokeratin.

BACKGROUND/AIMS: A series of premalignant lesions, including chronic gastritis (CG), intestinal metaplasia (IM) and dysplasia are associated with gastric carcinogenesis. The present study aimed to define these precancerous gastric lesions further by the study of the cellular DNA using flow cytometry, and the expression of the high molecular weight (68 KDa) Cytokeratin "CK1" proposed as a marker for epithelial cells dying by apoptosis.

MATERIAL AND METHODS

Multiple antral biopsies from each of 92 cases with gastric dyspepsia were subjected for DNA content analysis using flow cytometry, and immunostaining using anti-CK1 monoclonal antibody.

RESULTS

Chronic gastritis (CG) was present in 85 (92.4%) of cases, 14/85 (16.5%) cases showed chronic superficial gastritis (CSG), and 71/85 (83.5%) cases were chronic atrophic gastritis (CAG). Sixty two of the 85 (74.7%) cases with CG revealed variable degrees of activities. A hypodiploid "Sub-G1" peak was detected in 35 of 85 cases with CG. This peak was significantly higher in active chronic gastritis (ACG) than in the inactive (ICG) cases (p < 0.005). Proliferative activity of cases with CG was higher than in normal cases (p < 0.05) and in cases with ACG than in ICG (p < 0.05). Abnormal DNA-content (aneuploidy) was present in 16 (18.8%) of the 85 cases with CG. The presence of gastric epithelial cells with morphological changes typical of apoptosis in cases showing hypodiploid "Sub-G1" peak, high proliferation, and DNA-aneuploidy, suggests that these cells may be apoptotic bodies. Mild degree of apoptosis was present in some cases (57%) with histologically normal mucosa, while dense apoptotic bodies occurred in 87% of cases with chronic gastritis. These apoptotic bodies were constantly expressing CK1, except those in normal mucosa, suggesting that CK1 can be used as a marker for dying epithelial cells by apoptosis. CK1 was detected in 16 (100%) aneuploid cases which also showed apoptosis.

CONCLUSION

The presence of apoptotic bodies in cases with chronic gastritis especially in those showing DNA-aneuploidy, may accounts for the deletion of cells with altered DNA.