geranylgeranylacetone and Hypertension--Portal

Portal hypertensive gastropathy (PHG) is now recognized as a distinct entity; however, the angiogenesis in the portal hypertensive gastric mucosa has yet to be elucidated. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor involved in both physiological and pathological angiogenesis. The aim of this study was thus to examine the function of VEGF in the portal hypertensive and non-portal hypertensive gastric mucosa.. Forty-five cirrhotic patients were divided into 3 groups as follows. Group I included 15 patients without PHG who were treated with 1.5 g teprenone/day for 8 weeks: PHG(-)-t. Group II included 15 patients with PHG who were not treated with teprenone: PHG(+)-n. Group III included 15 patients with PHG who were treated with teprenone for 8 weeks: PGH(+)-t. The gastric mucosal blood flow (GMBF), the concentration of gastric mucosal VEGF and hexosamine and the endoscopic findings were studied both before and after medication.. Before teprenone treatment, the GMBF in the antrum, fundus, fornix were significantly higher in PHG(+)-n than PHG(-)-t. After treatment, the GMBF in the fundus and fornix significantly decreased more than before treatment in the PHG(+)-t. After treatment, the GMBF in the antrum increased significantly more than before treatment in PHG(-)-t. The gastric VEGF and hexoxamine concentration in the antrum were significantly higher in PHG(+)-n than in PHG(-)-t. After treatment, the gastric VEGF and hexosamine concentration in the antrum significantly decreased in PHG(+)-t while no change in concentration was recognized in PHG(+)-n. In the endoscopic findings, a decrease in the PHG score was recognized in 2 patients in PHG(+)-t.. Portal hypertensive gastric mucosal change was thus found to trigger a high concentration of VEGF and hexosamine. Such increased activity of VEGF and hexosamine may thus account for the presence of active congestion in PHG.

Topics: Adult; Aged; Anti-Ulcer Agents; Biopsy, Needle; Diterpenes; Dose-Response Relationship, Drug; Endothelial Growth Factors; Female; Gastric Mucosa; Gastroscopy; Hexosamines; Humans; Hypertension, Portal; Liver Cirrhosis; Lymphokines; Male; Middle Aged; Probability; Reference Values; Regional Blood Flow; Stomach Diseases; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

We have evaluated gastric mucus generation (study 1) and the effects of tetraprenylacetone on gastric mucus generation (study 2) in cirrhotic patients with portal hypertension. Study 1: Included were 50 noncirrhotics (group A), 25 cirrhotics without portal hypertension (group B), and 25 cirrhotics with portal hypertension (group C). The antrum, corpus, and fundus mucus generation was assessed by hexosamine concentration using biopsy specimens. In groups A and B, the antrum hexosamine concentration was significantly higher compared with the corpus (P < 0.01, P < 0.01) and the fundus (P < 0.01). In contrast, the hexosamine concentration at each location was similar in group C. Furthermore, the antrum hexosamine concentration of group C was significantly lower compared with that of group A (P < 0.05). In study 2, a double-blind design, 300 mg of tetraprenylacetone was administered for four weeks in 10 cirrhotics with portal hypertension and placebo in 10. The regional hexosamine concentrations were measured before and after drug administration. Placebo administration did not change hexosamine concentration at each location. In contrast, tetraprenylacetone increased the antrum and corpus hexosamine concentration (P < 0.01, P < 0.05), although the fundus concentration did not change. These data suggest that cirrhotics with portal hypertension have reduced gastric antral mucus generation and tetraprenylacetone normalizes this.

Topics: Anti-Ulcer Agents; Diterpenes; Female; Gastric Mucosa; Hexosamines; Humans; Hypertension, Portal; Liver Cirrhosis; Male; Middle Aged; Mucus; Reference Values; Stomach

Portal hypertensive (PHT) gastropathy results in an increased susceptibility to damage. Adaptive cytoprotection against ethanol-induced damage is impaired in the gastric mucosa of rats with portal hypertension. Excessive nitric oxide (NO) production occurs in portal hypertension and is mediated in part via heat-shock protein (Hsp)90 production. The aim of this study was to investigate the relation between adaptive cytoprotection after exposure to ethanol and gastric expression of Hsp90 in PHT rats.. Portal hypertension was induced in rats by staged portal vein occlusion. Adaptive cytoprotection to 70% ethanol was evaluated by assessing the injury index of the gastric mucosa with or without pretreatment with 10% ethanol. Expression of Hsp90 mRNA was evaluated by real-time polymerase chain reaction, and expression of Hsp90 protein was evaluated by western blotting. The effect of Hsp90 inhibition in PHT rats was evaluated by administration of geldanamycin.. Gastric Hsp90 mRNA expression in PHT rats was significantly less than that in sham-operated (SO) controls. However, after 10% ethanol pretreatment, Hsp90 mRNA expression was significantly greater in PHT rats than in SO controls. In PHT rats, gastric Hsp90 protein expression after 10% ethanol pretreatment was significantly greater than that without the pretreatment. However, the pretreatment had no effect on the injury index compared to SO rats. Administration of geldanamycin prior to 10% ethanol pretreatment significantly decreased the injury index in response to 70% ethanol in the PHT rats.. These results show that 10% ethanol pretreatment markedly increases gastric Hsp90 expression in PHT rats. Excessive production of Hsp90 may contribute impaired adaptive cytoprotection.

Topics: Animals; Blotting, Western; Cytoprotection; Diterpenes; Ethanol; Gastric Mucosa; HSP90 Heat-Shock Proteins; Hypertension, Portal; Male; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction

Teprenone (geranylgeranylacetone) is a gastric mucosal protective drug used clinically in Japan for treatment of gastric ulcers and gastritis. Its effect on portal hypertensive (PHT) gastric mucosa which has impaired defensive mechanisms is not known. In 20 PHT and 20 sham-operated rats, we studied the effects of teprenone or placebo on: (1) portal pressure; (2) gastric pH; (3) gastric mucosal blood flow using laser doppler flowmetry, and (4) hexosamine content in gastric mucosa. The gastric mucosal blood flow was significantly higher in the PHT + teprenone group than in the PHT + placebo group (463 +/- 75 and 381 +/- 82 perfusion units, respectively; p < 0.05). The hexosamine content was significantly lower in PHT rats than in sham-operated controls (12.6 +/- 2.3 vs. 14.3 +/- 2.2 micrograms/mg, respectively). Teprenone treatment significantly increased the gastric mucosal hexosamine concentration in both sham-operated and PHT rats (17.2 +/- 3.1 and 15.6 +/- 3.6 micrograms/mg, respectively). These effects of teprenone, combined with its known prostaglandin-stimulating action, suggest a potential role for this agent in the treatment of PHT gastric mucosal abnormalities.

Topics: Animals; Anti-Ulcer Agents; Blood Flow Velocity; Diterpenes; Gastric Mucosa; Hexosamines; Hydrogen-Ion Concentration; Hypertension, Portal; Laser-Doppler Flowmetry; Male; Portal Pressure; Rats; Rats, Sprague-Dawley