a novel vitamin e derivative (tmg) protects gastric mucosal damage induced by ischemia and...
TRANSCRIPT
April 2000
phoresis. The signals were quantified by spot-densitometry, relative to 18srRNA values. Both CAT-l and Pep'I'l were expressed at equivalent levelsin the duodenum and ileum of control animals. ASCT2 expression wasapproximately two-fold higher in the ileum than in the duodenum. CAT-lexpression was not affected by TPN in either duodenum or ileum. Expression of both Pep'TI and ASCT2 was significantly increased in the ileum ofTPN fed animals. Pep'I'l transcripts were increased to 296% of controlvalues (p<0.OO5) and ASCT2 transcripts to 220% (p<0.OO5). Expressionof both transcripts was not significantly altered in the duodenum (Pep'I'l:145%, p>0.05; ASCT2: 84%, p>O.4). The results demonstrate that expression of these transporters is not solely dependent on the presence ofluminal contents. In these calorifically-maintained animals, up-regulationof Pep'I'l and ASCT2 may reflect adaptational response to maintaining themetabolic requirements of the enterocytes in the absence of luminal nutrition. Supported by BBSRC
562A NOVEL VITAMIN E DERIVATIVE (TMG) PROTECTS GASTRIC MUCOSAL DAMAGE INDUCED BY ISCHEMIA ANDREPERFUSION.Hiroshi Ichikawa, Hirohisa Takano, Yuji Naito, Norimasa Yoshida,Toshikazu Yoshikawa, Motoharu Kondo, Kyoto Prefectural Univ of Medicine, Kyoto, Japan.
The antioxidative defense effect of a novel vitamin E derivative, 2-(a-Dglucopyranosyl) methyl-2,5,7,8-tetramethylchroman-6-01 (TMG), whichhas excellent water-solubility (> 1 x 103 mglml), was investigated using thereperfusion-induced rat gastric mucosal injury model in vivo. It has beenreported that TMG is somewhat located within the membrane surface andacts as a powerful antioxidant by scavenging radicals generated either inthe aqueous or in the lipid phase. Clamping the celiac artery for 30 mininduced ischemia, and reoxygenation was produced by removal of theclamp 60 min after ischemia. Just before removal of the vascular clamp,TMG at a dose of 0.4 - 4 mglkg dissolved in physiological saline wereinjected intravenously. The area of gastric mucosal erosion or ulcerativelesion (ulcer index) significantly increased from mean basal levels after 60min of reperfusion. This ulcer index was significantly inhibited by pretreatment with TMG. The concentration of thiobarbituric acid-reactivesubstances (TBA-RS) in the gastric mucosa, an index of lipid peroxidation,were also significantly higher than basal level after 60 min of reperfusion.This increase in TBA-RS in the gastric mucosa after ischemia-reperfusionwas inhibited by the pretreatment with TMG. Furthermore, myeloperoxidase (MPO) activity in the gastric mucosa, an index of neutrophil infiltration, significantly increased by ischemia reperfusion, and pretreatment ofTMG significantly reduced this increase of MPO activity in gastric mucosa.These results suggest that TMG may have protective effects against theoxidative stress in the reperfusion-induced injury models.
563THE MECHANISM OF GERMINATED BARLEY FOODSTUFF INATTENUATING INTESTINAL INFLAMMATION IN COLITIS.Osamu Kanauchi, Akira Andoh, Yoshio Araki, Keiichi Mitsuyama, Atsushi Toyonaga, Michio Sata, Toshifumi Hibi, Toshihiko Iwanaga, TadaoBamba, Kirin Brewery Co, Takasaki, Japan; Shiga Univ of Med Sci, Ohtsu,Japan; Kurume Univ Sch of Medicine, Kurume, Japan; Keio Univ Sch ofMedicine, Tokyo, Japan; Hokkaido Univ, Sch of Veternary Medicine,Sapporo, Japan.
Background and Aims: Germinated barley foodstuff (GBF) contains protein and insoluble dietary fiber. We have previously shown in ulcerativecolitis patients and colitis model that GBF feeding attenuates mucosaldamage by increasing luminal butyrate levels (Aliment Pharmacol Ther12:1225, 1998). However, the detailed mechanism remains unclear becauseof its heterogeneous nature. The present study was carried out to (1)evaluate the active ingredient in GBF, (2) to examine its effect on the repairprocess in colonic inflammation, and (3) to estimate its effect on luminalmicroflora by using a dextran sulfate sodium (DSS) colitis model. Methods: Colitis was induced by feeding a 0.5 % to 3.5 % DSS containing dietto male SD rats. (1) Active ingredient: GBF was fractionated enzymaticallyinto fiber- and protein-rich fractions. Each fraction was administered toDSS-colitis rats. Clinical signs, cecal short chain fatty acid (SCFA) concentrations and serum aI-acid glycoprotein (AAG) were determined. (2)Effect on mucosal repair: GBF with or without sulfasalazine (SASP), orSASP alone was administered to rats after the onset of colitis. Seven daysafter initial treatment, the number of epithelial cells in H&E sections wereevaluated morphologically in a blind fashion and serum AAG was determined. (3) Effect on microflora: Bacterial microflora and SCFA measurements in the luminal content was performed in colitis rats treated with orwithout GBF. Results: (1) GBF and GBF-fiber significantly attenuatedclinical signs of colitis (p<0.05) and decreased serum AAG (35.7 in GBF,43.6 in GBF-fiber vs 262.3 in control; p.g/ml p<O.OOl), with a significantincrease in cecal butyrate production (20.1 in GBF, 23.4 in GBF-fiber, 2.1in control p. moll g, p<0.05), while GBF-protein did not. (2)Treatment ofGBF alone and GBF with SASP significantly accelerated colonic epithelialrepair (76% in GBF, 70% in GBF with SASP vs 41% in control, p<0.05)and improved clinical signs (p<0.05). These effects were more potent thanwith SASP alone. (3) GBF feeding led to a significant increase in Eubacterium (8.2 in GBF vs 6.8 in control; log Ig, p<0.05) and a decrease inBacteroidaceae (p<0.05) were observed. Furthermore, Bifidobacteriumwas also increased along with a significant increase on butyrate production
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(p<0.05). Conclusions: These findings suggest that the fiber fraction ofGBF may effectively enhance luminal butyrate production by Eubacteriumand Bifidobacterium, and thereby accelerate colonic epithelial repair incolitis.
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A NON-TOXIC HEAT SHOCK PROTEIN 70 INDUCER, GERANYLGERANYLACETONE, EFFECTIVELY RESTORES THEHEAT SHOCK RESPONSE IN GASTRIC MUCOSA OF PROTEINMALNOURISHED RATS.Kazuhito Rokutan, Tomoko Kawai, Shigetada Teshima, Tsukasa Kawahara, Takeshi Nikawa, Kyoichi Kishi, Sch of Medicine, Univ of Tokushima, Tokushima, Japan.
Background: Protein malnutrition is inevitable for chronically ill patientswith wasting diseases and is linked to cachexia, immune dysfunction, andpoor prognosis. Protein-malnourished patients occasionally suffer fromsevere gastric mucosal damage when confronted with additionally stressfulsituations. However, it is usually difficult to effectively improve the nutritional state due to the underlying diseases. We report here that proteinmalnutrition inhibits heat shock protein (HSP) 70 induction in rat gastricmucosa and impairs the mucosal defense against stress ulcer. We alsoexamined whether a non-toxic HSP70 inducer, geranylgeranylacetone(GGA), effectively improved the mucosal integrity by stimulating HSP70induction under protein malnutrition. Methods: The present experimentswere approved by the Animal Care Committe, University of Tokushima.Male Wistar rats fed a 5% or a 20% casein diet for 3 weeks were exposedto restraint and water-immersion stress, and the ulcer index was measured.The activation of heat shock factor 1 (HSFl) was examined by gel mobilityshift assay with the heat shock element oligonucleotide. The level s ofHSP70 mRNA and protein were measured by Northern blotting andWestern blotting, respectively. Results and Conclusion: Protein malnutrition did not change the HSFllevel in the gastric mucosa, while the proteindeficiency attenuated the HSFI activation and inhibited the HSP70 mRNAexpression and HSP70 induction after exposure to the stress, leading toaggravate mucosal damage. A single or short-term administration of GGA(200 mglkg twice a day) to the protein-malnourished rats for up to oneweek failed to stimulate the heat shock response, while administration ofGGA for longer than 2 weeks restored the HSP70 induction, and 3 weekslater, the HSP70-inducing capacity of gastric mucosa of the proteinmalnourished rats recovered to the level of normally nourished rats. Theteatment of protein deficient rats with GGA for 3 weeks induced higherresistance against stress ulcer than that in control rats, suggesting othermechanism besides HSP70-inducing action may be involved in the enhanced mucosal integrity by GGA. GOA has been widely used in Japan asan antiulcer drug for more than 15 years without any serious adverseeffects. Our results suggest that GOA may have a potential benefit for theprevention of stress ulcer in chronically and/or critically ill patients withprotein malnutrition.
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FERMENTATION PRODUCTS OF ALCOHOLIC BEVERAGESMALEIC AND SUCCINIC ACID STIMULATE CCK RELEASE.Karlheinz Kiehne, Jan H. Egberts, Cornelia Wilgus, Stephan Teyssen,Ulrich R. Folsch, Karl-Heinz Herzig, I. Dept of Internal Medicine, Christian-Albrechts-Univ, Kiel, Germany; Univ of Heidelberg, Mannheim, Germany.
Alcoholic beverages with low ethanol content are powerful stimulants ofgastrin release and gastric acid output in humans (Singer et al. 1991).Subsequent studies revealed that fermentation but not distillation producedthe stimulators (Teyssen et al. 1997). Recently, maleic and succinic acidhave been identified as stimulants of gastric acid secretion from fermentedalcoholic beverages (Teyssen et al. 1999). Furthermore, wine and beersignificantly increased meal-stimulated pancreatic secretion in humans(Hajnal et al. 1990). Therefore, in this study we investigated the effect ofmaleic and succinic acid on CCK release using isolated perfused mucosalcells and the neuroendocrine cell line STC-l. Methods: Isolated cells wereobtained by incubation of rat prox. small bowel in Ca2+ -free buffer. Aftercentrifugation, washing, filtration the cells were mixed with Sephadex G50and transferred into a perfusion apparatus and continously perfused. Theneuroendocrine cell line STC-l was seeded (l05 cells/ml) into 6-well platesreaching more than 90% confluence after 3-4 days. CCK determination wasmeasured using a pancreatic bioassay system. Maleic and succinic acid didnot affect amylase secretion from isolated acini. Results: In isolated duodenal cells, maleic and succinic acid dose-dependently stimulated CCKrelease from 2,7:t0,3 to B,I:tl,7 and 27,1:t3,4pM at lmM, an amount,which is found in finished beer (Piendl 1980). At lOOnM succinic but notmaleic acid still stimulated CCK release to 8±0,9pM. In addition, in theneuroendocrine cell line STC-I maleic and succinic acid dose-dependentlystimulated CCK release from 3,1:to,3 to 8,9:t 1,5 and Il,7:t2,3pM at100nM, respectively. Pretreatment of the cells with the voltage-gatedL-type calcium channel blocker diltiazem significantly inhibited maleicand succinic acid stimulated CCK release. Conclusion: These data identifymaleic and succinic acid as potent direct stimuli of CCK release viaincreases in intracellular calcium mediated by voltage-gated L-type calcium channels.