Regeneration of gastric mucosa during ulcer healing is triggered by growth factors and signal transduction pathways

Thiamine Transporter Gene Expression and Exogenous Thiamine Modulate the Expression of Genes Involved in Drug and Prostaglandin Metabolism in Breast Cancer Cells

In previous studies, we have shown that RNA levels of the thiamine transporter THTR2 were down-regulated in breast cancer tumors in comparison with normal tissues and that THTR2-mediated increases in thiamine uptake activity contributed to increased apoptosis after exposure to ionizing radiation. To further understand the biological effects of the alteration of THTR2 expression, we conducted a DNA microarray study of gene expression in THTR2-transfected breast cancer cells and found that, in addition to increased expression of THTR2 attributable to the transgene, three other genes were up-regulated >2.5-fold in the transfected cells: cytochrome P450 isoform CYP4B1, 15-hydroxyprostaglandin dehydrogenase (15-PGDH), and transcription factor CRIP1. In addition, two genes were confirmed to be down-regulated in THTR2-transfected cells: trefoil factor 1 (TFF1) and Rho-GDP dissociation inhibitor (RGDI). Up-regulation of 15-PGDH and CYP4B1 expression was observed in other breast cancer cell lines transfected with THTR2, and down-regulation was observed after suppression of THTR2 with siRNA vectors. To determine the role of exogenous thiamine in the expression of these genes, we analyzed THTR2-transfected breast cancer cells grown in thiamine-depleted medium by quantitative reverse transcription-PCR and showed that three of these five genes showed evidence of regulation by exogenous thiamine in a manner concordant with the effects of THTR2 overexpression. One of the genes up-regulated by THTR2 transfection was down-regulated by thiamine depletion (CYP4B1), and two genes with decreased expression in THTR2-transfected breast cancer cells were up-regulated by thiamine depletion (TFF1 and RGDI). In summary, these studies show unexpected relationships between thiamine metabolism and genes that may be involved in the oncogenesis of breast and lung cancer.

Mucosal irritative and healing impairment action of risedronate in rat stomachs: comparison with alendronate

BACKGROUND AND AIM

We used alendronate and risedronate as bisphosphonates and examined whether or not these agents have a mucosal irritative action in the stomach and impair the healing of pre-existing gastric ulcers in rats.

METHODS

Male Sprague Dawley (SD) rats were used in the following two studies: (i) the effects of risedronate and alendronate on gastric potential difference (PD), gastric mucosal blood flow (GMBF) and acid back-diffusion in the stomach mounted on ex vivo chamber under urethane anesthesia and; (ii) the influence of daily treatment with these drugs on the healing of acetic acid-induced gastric ulcers was examined.

RESULTS

Mucosal application of risedronate produced PD reduction in the saline-perfused stomachs in a dose-dependent manner. Alendronate also produced a marked PD reduction, the effect being more potent than that of risedronate. In the stomach exposed to acid (100 mM HCl), both drugs produced a marked reduction in PD, followed by acid back-diffusion and a small increase in GMBF, resulting in hemorrhagic lesions, and the effects again were more pronounced with alendronate. These irritative effects were dependent on the pH of drug solution and the action was more potent at pH 7 than pH 4. Conversely, the healing of acetic acid-induced gastric ulcers was significantly delayed by daily administration of these drugs, yet this effect was less pronounced in the case of risedronate. The healing impairing effect of these bisphosphonates was potentiated by coadministration of indomethacin.

CONCLUSION

Both alendronate and risedronate have mucosal irritative and healing impairing effects in the stomach, yet the effect of risedronate was much less pronounced compared to alendronate. It is assumed that risedronate is safer than alendronate as the antiresorptive agent in patients with diseases related to bone remodeling.

Expression of basic fibroblast growth factor(bFGF) in healing human gastric ulcer

AIM: To investigate changes of basic fibroblast growth factor (bFGF) in the healing of human gastric ulcer.

METHODS: The expression of basic fibroblast growth factor (bFGF) in human gastric mucosa: normal (20 cases), active stage of gastric ulcer (24 cases), healing stage of gastric ulcer (26 cases) and scarring stage of gastric ulcer (20 cases) was detected by immunohistochemical methods and computerized image analysis.

RESULTS: The expression intensity of bFGF was different among normal gastric mucosa and mucosa at different stages of gastric ulcer. The expression in normal gastric mucosa was weakly positive, at the active stage of gastric ulcer was positive, at the healing stage and scarring stage was strongly positive. The positive signal of bFGF was localized in granulation tissues, extracellular matrix (ECM), fibroblasts and endothelial cells. There were significant differences in average integral optic density and area density among different stages of gastric ulcer and normal gastric mucosa (0.247±0.042, 0.321±0.096, 0.296±0.048 vs 0.125±0.062 P < 0.05; 0.131±0.024, 0.165±0.031, 0.162±0.028 vs 0.081±0.008, P < 0.05) They were significantly higher at the healing stage and scarring stage than that at the active stage in average integral optic density and area density (0.321±0.096, 0.296±0.048 vs 0.247±0.042, P < 0.05; 0.165±0.031, 0.162±0.028 vs 0.131±0.024, P < 0.05).

CONCLUSION: The changes of bFGF were closely related to the healing of human gastric ulcer, and rational use of bFGF can promote the healing of gastric ulcer.

Effect of polysaccharides from Angelica sinensis on gastric ulcer healing

Our previous study showed that a crude extract from Angelica sinensis (ASCE), which mainly consisted of polysaccharides, significantly promoted migration and proliferation of normal gastric epithelial cells. These results strongly suggest that ASCE has a direct wound healing effect on gastric mucosa. However, there is no report concerning the effect of ASCE on gastric ulcer healing in animal models. In this study, we found that ASCE promoted ulcer healing. The area of the ulcer was reduced. This was accompanied with a significant increase in mucus synthesis when compared with the control. Angiogenesis was inhibited by the treatment of ASCE. Cell proliferation, ODC and EGFR protein expression was not affected in this process. Thus, the mechanism of how ASCE accelerates ulcer healing in addition to its effect on mucus synthesis remains to be investigated.