Aspirin effects on gastric epithelial cell proliferation and cytokine expression

Mitochondrial alterations in human gastric carcinoma cell line

We compared mitochondrial function, morphology, and proteome in the rat normal gastric cell line RGM-1 and the human gastric cancer cell line AGS. Total numbers and cross-sectional sizes of mitochondria were smaller in AGS cells. Mitochondria in AGS cells were deformed and consumed less oxygen. Confocal microscopy indicated that the mitochondrial inner membrane potential was hyperpolarized and the mitochondrial Ca(2+) concentration was elevated in AGS cells. Interestingly, two-dimensional electrophoresis proteomics on the mitochondria-enriched fraction revealed high expression of four mitochondrial proteins in AGS cells: ubiquinol-cytochrome c reductase, mitochondrial short-chain enoyl-coenzyme A hydratase-1, heat shock protein 60, and mitochondria elongation factor Tu. The results provide clues as to the mechanism of the mitochondrial changes in cancer at the protein level and may serve as potential cancer biomarkers in mitochondria.

Fibrin glue, healing of gastric mucosal injury, and expression of growth factors: results from a human in vivo study

BACKGROUND

Fibrin glue is used in the endoscopic therapy of bleeding ulcerations. Accelerated closure of ulcers has been attributed to this treatment; the biologic reason, however, remains unclear.

METHODS

Two artificial gastric lesions were induced in healthy, Helicobacter pylori negative volunteers and were treated by injection of either saline solution or fibrin glue. After 72 hours, resulting ulcers were measured and biopsy specimens were taken for immunohistochemistry (to identify proliferating cells and small vessels) and assessment of growth factor messenger RNA (mRNA) expression (platelet derived growth factor, vascular endothelial growth factor, fibroblast growth factor 2 [FGF-2]) by real-time reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

After 72 hours, most lesions exposed to fibrin glue were smaller than the corresponding ones treated with saline solution. The ulcer rim was more pronounced; immunohistochemistry revealed more proliferating cells (p < 0.02 compared with saline solution). The number of microvessels also increased, though this difference did not reach statistical significance (p = 0.10). FGF-2 mRNA expression markedly increased (about 7-fold compared with the control [ p < 0.001], and about 5-fold compared with saline solution [ p < 0.015]); whereas, with respect to platelet derived growth factor and vascular endothelial growth factor mRNAs, only small changes occurred.

CONCLUSIONS

Fibrin glue positively modulates gastric ulcer healing by causing an increase in the number of proliferating cells in the ulcer margin and also possibly enhances the density of microvessels. These changes are accompanied by an enhanced expression of FGF-2, which is known to exert beneficial effects on ulcer healing.

Dynamics and localization of activin A expression in rat gastric ulcers

BACKGROUND

Activin A, the homodimer of the activin/inhibin betaA subunit, has been shown to participate in cutaneous wound healing. In this study we intended to determine its part in gastric ulceration.

METHODS

Activin A expression was studied by immunohistochemistry and in situ hybridization in acetic-acid-induced chronic gastric ulcers in rat. The dynamics of this process were also assessed by quantitative real time RT-PCR and RNase protection assays (RPA). The effects of different doses of this cytokine on epithelial and mesenchymal cell proliferation were quantitated in vitro.

RESULTS

Low amounts of activin A and its mRNA were expressed by epithelia, endothelia and fibroblasts in intact gastric tissue. Granulation tissue of gastric ulcers and gastric glands adjacent to the ulcer rim expressed markedly increased amounts of activin protein as well as activin/inhibin betaA mRNA. RPA and RT-PCR studies revealed a more than 3-fold increase in the relative abundance of this mRNA. Activin A did not affect the proliferation rate of fibroblasts and epithelial cells in vitro.

CONCLUSIONS

Activin A participates in gastric ulcer healing in a similar fashion as in cutaneous wounding. Its expression on protein and mRNA level is markedly increased in ulcer base and rim.