Xian-En Wang

Basic fibroblast growth factor accelerates gastric mucosal restoration in vitro by promoting mesenchymal cell migration and proliferation.

It has been generally accepted that basic fibroblast growth factor is a potent stimulator of duodenal ulcer healing. However, the detailed mechanism and mode of action of growth factor on gastric ulcer healing is still controversial. Therefore, in the present study, the effects of basic fibroblast growth factor on gastric mucosal repair were studied using an in vitro cultured cell system. Artificial wounds were made in confluent monolayer rabbit gastric fibroblast and epithelial cell sheets by mechanical denudation. Changes in the size of the cell‐free area were analysed quantitatively. Cell proliferation was assessed by BrdU staining. For both cell types, mucosal restoration involved cell migration and proliferation. Although the speed of restoration of epithelial cells was not affected by the addition of basic fibroblast growth factor, it was much faster for epithelial cells than for fibroblasts. Basic fibroblast growth factor accelerated wound repair of fibroblasts but not epithelial cells. Basic fibroblast growth factor accelerated wound repair by stimulating both cell migration and proliferation. Therefore, the effects of basic fibroblast growth factor in peptic ulcer diseases may be mainly due to the stimulation of mesenchymal cells.

Effects of rebamipide on bile acid-induced inhibition of gastric epithelial repair in a rabbit cell culture model

Background: Anti‐ulcer agents exert various functional effects on gastric epithelial cells.

ACTIVATED STELLATE (ITO) CELLS POSSESS VOLTAGE-ACTIVATED CALCIUM CURRENT

We previously reported stellate (Ito) cells possess voltage-activated Ca2+ current. The activation of stellate cells has been indicated to contribute to liver fibrosis and the regulation of hepatic hemodynamics. The aim of this study was to investigate the relationship between voltage-activated Ca2+ current and activation of stellate cells. Voltage-activated Ca2+ current in stellate cells isolated from rats were studied using whole-cell patch clamp technique. L-type voltage-activated Ca2+ current was hardly detected in stellate cells cultured for less than 9 days. Ca2+ current was detected 12.5 and 69% of cells at the 10th and 14th day of culture, respectively. BrdU incorporation indicated cell proliferation was recognized over 50% of cells at the 3rd and 5th day of culture, respectively, then decreased significantly in a time-dependent manner. On the other hand, the expression of alpha-smooth muscle actin indicated cell activation increased from 7th day of culture and collagen type I mRNA appeared remarkably in cells cultured for more than 10 days. In this study, we concluded L-type voltage-activated Ca2+ current was recognized in activated stellate (myofibroblast-like) cells.

A neurotrophic pyrimidine compound, MS-818, enhances EGF-induced restoration of gastric epithelial wounds in vitro

MS-818 is a novel synthetic pyrimidine compound that stimulates nerve regeneration and promotes synthesis of various growth factors and differentiation of astrocytes. Effects of MS-818 on gastric epithelial cells were assessed using a wound repair model with primary cultured gastric epithelial cells from rabbits. A round wound with a constant cell-free area was created and the process of restoration was monitored by measuring wound size every 12 h. Cell proliferation was monitored by sequential staining with BrdU. As previously reported, EGF (10 ng/ml) accelerated wound repair by promoting cell migration and proliferation. Although MS-818 alone had no effects, MS-818 (10-100 microM) enhanced EGF-induced acceleration of gastric epithelial restoration, including cell migration and proliferation. Although the detailed mechanism of action of this agent is still unclear, MS-818 might have favorable effects on in vivo gastric mucosal repair.

Hepatic stellate cell contraction is inhibited by lipo-prostaglandin E1 in vitro

Prostaglandin E1 (PGE1) has been reported to have, experimentally and clinically, a protective effect against liver damage. This effect may result from the relaxation of hepatic stellate cells, whose contraction induces vasoconstriction of hepatic sinusoids. However, prostaglandins are unstable and a new drug delivery system is necessary to administer a sufficient amount of prostaglandin to achieve a protective effect in the liver. The aim of the study is to investigate the effects of lipo‐prostaglandin E1 (lipo‐PGE1) which has a novel drug delivery system on the stellate cell contraction induced by endothelin‐1 in vitro. Lipo‐PGE1 inhibited endothelin‐1‐induced stellate cell contraction in concentrations of 10, 30 and 50 ng/mL. Therefore, lipo‐PGE1 may show a cytoprotective effect in the liver through the relaxation of stellate cells and an increase in the hepatic sinusoidal blood flow.

Effect of nicotine in migration and proliferation of rabbit gastric mucosal cells in a culture cell model

Abstract The aim of this study was to assess the effects of nicotine on the gastric epithelial restoration using primary cultured rabbit gastric mucosal cell model.

Integrity of myosin light chain kinase is essential for Ito cell contraction

Hepatic sinusoidal Ito cells (fat storing cells) are believed to play a regulatory role on hepatic sinusoidal blood flow through their contraction. The detailed mechanism of contraction of Ito cells, however, is still unknown. The present study was undertaken to clarify the effect of new myosin light chain kinase inhibitor, wortmannin, on Ito cell contraction. Ito cells prepared from rat liver were cultured for 4 days before the study. The contraction of Ito cells, which was monitored and analysed by time‐lapse video tape recording, was triggered by addition of endothelin‐1. Wortmannin pretreatment for 1 h inhibited endothelin‐induced Ito cell contraction dose‐dependently. Therefore, the integrity of the actomyosin system is essential for Ito cell contraction and normal sinusoidal blood flow.

A WATER EXTRACT OF HELICOBACTER PYLORI INHIBITED GASTRIC EPITHELIAL RESTORATION IN VITRO.

Accumulated evidence shows that Helicobacter pylori(HP) plays a key role in the pathogenesis of active chronic gastritis and peptic ulceration. The detail mechanism by which HP elicits these lesions is still unclear but may include both direct and indirect effects. Recently, we established a new wound repair model which included cell migration and proliferation using primary cultured gastric epithelial cells. In this study, we assessed the direct effects of a water extract from CagA gone positive HP on gastric epithelial restoration. METHOD:Isolated rabbit gastric epithelial cells (92% mucous cells) were cultured in F-12 medium and formed complete monolayer cell sheet in 48h. A round shaped wound with constant Cell-free area (2mm 2) was created by mechanical cell denudation. The restoration process was monitored by the measuring wound size every 12h. The cell proliferation was monitored by the sequential staining for BrdU A water soluble HP extract was prepared from CagA gene positive strain. After centrifugation, the supematant (dilution: 50x, 100x) was added to the wounded gastric epithelial cell culture for 48h. RESULT: The change of the size of cell-free area during restoration in the presence or absence of HP extract was presented in a table. Data:mean--SD, n=4, number:ram 2, *p<0.05 vs control.

Effects of teprenone on gastric epithelial restoration in a rabbit cultured cell model

Abstract: The mechanism of action of gastrocytoprotective agents is not fully understood. We assessed the effects of an anti-ulcer agent, teprenone, and bile acid on epithelial restoration. Teprenone with or without deoxycholic acid was added to a complete confluent cultured gastric epithelial cell sheet after wounding. Restoration was monitored for 48 h, and the wound size was assessed. Migration velocity was measured, and proliferation was detected by sequential staining with bromodeoxyuridine. The labeling index was calculated. Restoration was completed within 48 h in controls, whereas deoxycholic acid retarded repair. The migration velocity was suppressed by deoxycholic acid treatment. The number of proliferative cells peaked at 36 h (labeling index, 1.7%) in controls. In the deoxycholic acid group, the maximal labeling index was 0.5% at 48 h. Teprenone abolished the bile acid-induced retardation. Teprenone showed cytoprotective effects against deoxycholic acid-induced inhibition of epithelial cell migration and proliferation.

The novel histamine H2 receptor antagonist FRG-8813 prevents delay of wound repair induced by hydrogen peroxide in a rabbit gastric epithelial cell system

Abstract The effects of a novel histamine H2 receptor antagonist (FRG‐8813) on the restoration process of gastric epithelial wounds were assessed using an in vitro wound healing model. FRG‐8813 (1, 10 mol/L) was added to a complete confluent monolayer cell sheet after artificial wounding. The restoration process was analysed by a time‐lapse video system and cell migration, proliferation and apoptosis were assessed. Hydrogen peroxide (1, 3 mmol/L) inhibited restoration after wounding by suppressing cell migration and proliferation and induced epithelial cell apoptosis around the wound. The addition of FRG‐8813 abolished the hydrogen peroxide‐induced retardation and prevented apoptosis, although FRG‐8813 itself did not enhance wound healing. FRG‐8813 may act as a radical scavenger as well as having an anti‐secretory action and may have favourable effects on peptic ulcer healing.