Immunohistochemccal approach reveals localizatin of cystathionine--lyase and ccystathionine--synthetase in ethanol-induced gastric mucosa damage in mice

Context Hydrogen sulphide (H2S) has been proved to be a neuromodulator and contributes to the maintenance of gastric mucosal integrity in damage caused by anti-inflammatory nonsteroidal drugs. Previously, we demonstrated that H2S synthesis is essential to gastric protection against ethanol. Objective To better understanding the role of H2S and the detailed localization of its production in both normal and injured stomach due to ethanol injection, we studied the expression of cystathionine-γ-lyase (CSE) and cystathionine-β-synthetase (CBS) isoforms in gastric mucosa of mice treated with saline or 50% ethanol. Methods Mice were treated by gavage with saline or 50% ethanol (0.5 mL/25 g). After 1 hour, mice were sacrificed, and gastric tissue was evaluated by histological and immunohistochemical analysis specific for CSE and CBS. Results We have demonstrated a non-specific expression of CBS in the normal gastric mucosa and expression of CSE occurring mainly in the parietal cells of the animals treated with ethanol. Conclusion Thus, we demonstrated that the expression of CBS appears to be constitutive and diffuse across the gastric epithelium, while the expression of CSE appears to be induced in parietal cells by damage agents such as ethanol. .

Contexto O sulfeto de hidrogênio (H2S) tem sido mostrado como um neuromodulador e contribuidor para a manutenção da integridade da mucosa gástrica na lesão causada por drogas antiinflamatórias não esteroidais. Previamente, demonstramos que a síntese de H2S é essencial para a proteção da mucosa gástrica contra a administração de etanol. Objetivo Para compreender o papel do H2S e a localização detalhada de sua produção no estômago normal e após lesão induzida pela administração de etanol, estudou-se a expressão das isoformas cistationina-γ-liase (CSE) e cistationina-β-sintetase (CBS) na mucosa gástrica de camundongos tratados com salina ou etanol 50%. Métodos Os camundongos foram tratados por gavagem com salina ou etanol 50% (0,5 mL/25 g). Após 1 hora, os camundongos foram sacrificados e os tecidos gástricos foram avaliados por análise histológica e imunoistoquímica específica para CBS e CSE. Resultados Foi demonstrado expressão não específica de CBS na mucosa gástrica normal e expressão de CSE ocorrendo principalmente nas células parietais dos animais tratados com etanol. Conclusão Assim, demonstramos que a expressão de CBS parece ser constitutiva e difusa através do epitélio gástrico, enquanto a expressão de CSE parece ser induzida nas células parietais por agentes lesivos como o etanol. .

Effect of Pertussis Toxin and Herbimycin A on Proteinase-Activated Receptor 2-Mediated Cyclooxygenase 2 Expression in Helicobacter pylori-Infected Gastric Epithelial AGS Cells

Helicobacter pylori (H. pylori) is an important risk factor for chronic gastritis, peptic ulcer, and gastric cancer. Proteinase-activated receptor 2 (PAR2), subgroup of G-protein coupled receptor family, is highly expressed in gastric cancer, and chronic expression of cyclooxygenase-2 (COX-2) plays an important role in H. pylori-associated gastric carcinogenesis and inflammation. We previously demonstrated that H. pylori induced the expression of PAR2 and COX-2 in gastric epithelial cells. Present study aims to investigate whether COX-2 expression induced by H. pylori in Korean isolates is mediated by PAR2 via activation of Gi protein and Src kinase in gastric epithelial AGS cells. Results showed that H. pylori-induced COX-2 expression was inhibited in the cells transfected with antisense oligonucleotide for PAR2 or treated with Gi protein blocker pertussis toxin, Src kinase inhibitor herbimycin A and soybean trypsin inbitor, indicating that COX-2 expression is mediated by PAR2 through activation of Gi protein and Src kinase in gastric epithelial cells infected with H. pylori in Korean isolates. Thus, targeting the activation of PAR2 may be beneficial for prevention or treatment of gastric inflammation and carcinogenesis associated with H. pylori infection.

The Change of Cyclooxygenase-2 and Inducible Nitric Oxide Synthase in the Gastric Mucosa One Year after Eradication of Helicobacter pylori / 대한소화기학회지

BACKGROUND/AIMS: The cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), the proteins that have the role in the gastric carcinogenesis, are stimulated by H. pylori infection in the gastric mucosa. The aim of this study was to evaluate the expression of COX-2 and iNOS proteins one year after the eradication of H. pylori. METHODS: Gastric antral mucosa from fifty eight patients with chronic gastritis who were all infected with H. pylori was examined for the expression of COX-2 and iNOS proteins before and one year after the eradication of H. pylori by immunohistochemical stain. RESULTS: COX-2 and iNOS proteins were expressed in the epithelial cells and interstitial inflammatory cells of gastric mucosa. Percent expressions of COX-2 and iNOS were significantly decreased one year after the eradication in the patients with cured infection, but not in those having persistent H. pylori. COX-2 and iNOS expressions were well correlated with H. pylori density, acute and chronic inflammation of gastric mucosa. CONCLUSIONS: The eradication of H. pylori can decrease the expression of COX-2 and iNOS in the gastric mucosa in long-term period. This seems to be due to the removal of H. pylori itself and related regression of gastric inflammation.

Over-expression of cyclooxygenase-2 in endoscopic biopsies of ectopic gastric mucosa

Ectopic gastric mucosa (EGM) is considered to be a congenital condition. Rare cases of adenocarcinoma have been described. There are no data justifying regular biopsies or follow-up. Cyclooxygenase-2 (COX-2) is a protein involved in gastrointestinal tumor development by inhibiting apoptosis and regulating angiogenesis. The aim of this prospective study was to evaluate COX-2 expression in EGM and compare it with normal tissue and Barrett's esophagus. We evaluated 1327 patients. Biopsies were taken from the inlet patch for histological evaluation and from the gastric antrum to assess Helicobacter pylori infection. Biopsies taken from normal esophageal, gastric antrum and body mucosa and Barrett's esophagus were retrieved from a tissue bank. EGM biopsies were evaluated with respect to type of epithelium, presence of H. pylori, and inflammation. COX-2 was detected by immunohistochemistry using the avidin-biotin complex. EGM islets were found in 14 patients (1.1 percent). Histological examination revealed fundic type epithelium in 58.3 percent of cases, H. pylori was present in 50 percent and chronic inflammation in 66.7 percent. Expression of COX-2 was negative in normal distal esophagus, normal gastric antrum and normal gastric body specimens (10 each). In contrast, EGM presented over-expression of COX-2 in 41.7 percent of cases and Barrett's esophagus in 90 percent of cases (P = 0.04 and 0.03, respectively). COX-2 immunoexpression in EGM was not related to gender, age, epithelium type, presence of inflammation or intestinal metaplasia, H. pylori infection, or any endoscopic finding. Our results demonstrate up-regulation of COX-2 in EGM, suggesting a possible malignant potential of this so-called harmless mucosa.

Inhibition of N-Methyl N'-nitro-N-nitrosoguanidine (MNNG) induced gastric carcinogenesis by Phyllanthus amarus extract.

Chemopreventive activity of Phyllanthus amarus Schum & Thonn (Euphorbiaceae) extract was studied with regard to N-methyl N'-nitro-N-nitrosoguanidine (MNNG) induced stomach cancer in Wistar rats. Administration of the extract with MNNG significantly reduced the incidence of gastric neoplasms in rats (44%) as well as their numbers. Moreover, elevated levels of enzymes in the stomach were found to be reduced by P. amarus administration. For example, gamma-glutamyl transpeptidase activity was decreased from 20.3 +/- 6.7 mmol/min/mg protein to almost normal levels (2.8 +/- 0.9) by 750 mg/kg body weight of the extract. Similarly glutathione S-transferase activity (1317.6 +/- 211 n mol/min/mg protein) and glutathione reductase (368 +/- 66) levels in the MNNG treated group were found to be lowered to 494.8 +/- 76 and 192 +/- 45, respectively, while reduced glutathione (GSH) was increased from 4.6+/- 0.9 to 8.5+/-1.4 n mol/min/mg protein. AgNOR dots and clusters, indicators of cellular proliferation, which were increased by MNNG treatment, became near to normal in P. amarus treated animals.

Alterações gastrointestinais no diabetes mellitus: estresse oxidativo e fluxo sangüíneo da artéria mesentérica - estudo experimental / Gastrointestinal alterations in diabetes mellitus: oxidative stress and blood flow in the superior mesenteric artery - experimental study

RACIONAL: Os sintomas gastrointestinais são freqüentes no diabetes mellitus e podem estar relacionados com o estresse oxidativo, que é definido pelo desequilíbrio entre os sistemas pró-oxidante e o antioxidante. OBJETIVO: Avaliar algumas das alterações gastrointestinais no modelo de diabetes mellitus, como o estresse oxidativo no estômago e no fígado de animais diabéticos e o fluxo sangüíneo na artéria mesentérica superior em diferentes tempos de estudo. MATERIAL E MÉTODOS: Os parâmetros utilizados para verificar o estresse oxidativo no fígado e no estômago foram a mensuração da lipoperoxidação, através das técnicas das substâncias reativas ao ácido tiobarbitúrico e da quimiluminescência e a avaliação da atividade das enzimas antioxidantes catalase, superóxido dismutase e glutationa transferase. Utilizaram-se ratos machos Wistar, pesando entre 250-350 g, que foram divididos em quatro grupos: grupo I - 7 dias de diabetes, grupo II- 30 dias de diabetes, grupo III - 60 dias de diabetes e grupo IV - 90 dias de diabetes. O diabetes foi induzido por administração de estreptozotocina 70 mg/kg intraperitonialmente. RESULTADOS: Houve aumento significativo na lipoperoxidação no estômago e no fígado de animais diabéticos somente no tempo de 90 dias. No estômago, foi encontrada significativa diminuição na atividade das enzimas antioxidantes catalase e glutationa transferase. No fígado, somente a enzima glutationa transferase apresentou diminuição significativa. Houve aumento no fluxo da artéria mesentérica superior dos animais diabéticos com 90 dias, quando comparados aos animais-controle. CONCLUSÕES: É possível supor que o aumento no estresse oxidativo no estômago e no fígado e a alteração no fluxo sangüíneo da artéria mesentérica superior sejam influenciados pelo tempo de diabetes e pela hiperglicemia encontrada nos animais estudados, o que determinaria as alterações gastrointestinais.

The Changes of Matrix Metalloproteinase-9 Expression in the Gastric Antral Mucosa after Helicobacter pylori Eradication: Immunohistochemical Study / 대한소화기학회지

BACKGROUND/AIMS: In this study, we analysed the changes of matrix metalloproteinase-9 (MMP-9) expression in the gastric antral epithelium in respect to H. pylori eradication. METHODS: Twenty patients with H. pylori-positive chronic gastritis or peptic ulcer were studied. The expression of MMP-9 in the gastric antral biopsy specimens were compared before and after H. pylori eradication using immunohistochemical study. The positive rates and intensity of MMP-9 staining were evaluated at surface mucous cells and pyloric gland cells. RESULTS: The positive rate of MMP-9 staining in antral mucosal epithelial cells of H. pylori chronic gastritis is 63.8%. The positive rates of MMP-9 staining in the surface mucous cells and pyloric gland cells were 75.5% and 52.0% before H. pylori eradication, respectively. On the contrary, the rates were 85.5% and 82.0% after eradication. The MMP-9 overexpression in the pyloric gland cells were noticeably increased after H. pylori eradication. Strong positive staining of MMP-9 was increased significantly after H. pylori eradication in the pyloric gland cells. CONCLUSIONS: These results suggest that MMP-9 over-expression is associated with H. pylori infection as a host inflammatory response. The increased expression after H. pylori eradication indicates that MMP-9 may have a important role in remodeling or early tissue repairing process of gastric mucosa.

Effect of malnutrition on the digestive enzymes of the upper gastrointestinal tract of young rhesus monkeys.

The present study was planned to observe the effect of protein-energy malnutrition on the gastric and duodenal mucosa. The activities of digestive enzymes (i.e. lactase, sucrase, maltase, trehalase, glucoamylase, leucine aminopeptidase, alkaline phosphatase and gamma-glutamyl transpeptidase) from the gastric (fundus, body and antrum) and duodenal mucosa [i.e. first (D1) and second (D2) part of the duodenum] were determined in 6 control, 6 protein-energy malnourished (PEM) and 6 rehabilitated young rhesus monkeys. There was a significant increase in the activity of the lactase enzyme in the antrum, and D1 and D2 portions of the duodenum of PEM monkeys, while the activity of all other enzymes was significantly increased in the D1 and D2 portions only. The increase in the activity of the above-mentioned enzymes became normal upon rehabilitation. There was no change in the enzyme activities of the gastric mucosa in mild-to-moderate PEM states. This study demonstrates that even mild-to-moderate malnutrition states affect the activity of enzymes in the gastric and duodenal mucosa. Enzyme activity recovers on rehabilitation.

Measurement of Telomerase Activity and Telomerase Reverse Transcriptase Expression in Gastric Fluid and Tissue for Early Diagnosis of Stomach Cancer / 대한소화기학회지

BACKGROUND/AIMS: Telomerase activity and telomerase reverse transcriptase (TERT) expression have been proposed as a marker for malignancy. However, little is known about those markers in intestinal metaplasia (IM). This study was performed to evaluate the usefulness of telomerase activity in gastric washing fluid and TERT expression in tissue as a marker for early diagnosis of stomach cancer. METHODS: Gastric washing fluid and biopsies were taken endoscopically. We examined the telomerase activity by telomeric repeat amplification protocol (TRAP) and the TERT expression by semiquantitative reverse transcription-polymerase chain reaction in 26, 21 and 15 cases of cancer, IM, and normal mucosa respectively. RESULTS: The telomerase activity was positive in 65% of cancer, 44% of incomplete IM, and 33% of complete IM. The TERT was expressed in 89% of cancer, 81% of IM, but not in normal mucosa. The TERT expression level was higher in cancer and incomplete IM than in complete IM and normal mucosa (p<0.05). CONCLUSIONS: Telomerase activity in gastric washing fluid and TERT expression in tissue may have limited usefulness as a marker for the early diagnosis of stomach cancer. However, the increased levels of TERT expression in IM and cancer suggest that TERT expression may be associated with carcinogenesis in stomach cancer.

Metaplasia intestinal e carcinoma gástrico: correlação com os subtipos histológicos da neoplasia / Intestinal metaplasia and gastric carcinoma: a correlation with the neoplasm histological subtypes

Introdução: O papel da metaplasia intestinal (MI) como lesão pré-cancerosa gástrica não está completamente esclarecido. Objetivos: Analisar a distribuição e o tipo de MI em relação aos tipos de carcinoma gástrico (CG). Material e Método: Analisaram-se 71 peças de gastrectomia por CG. Amostras da neoplasia e da mucosa a intervalos regulares de toda a peça foram processadas rotineiramente; os cortes histológicos foram corados por HE e histoquímica para mucinas. A gastrite crônica atrófica (GCA) e a MI foram analisadas quanto a topografia, intensidade e tipo e correlacionadas com o subtipo da neoplasia. Resultados: Diagnosticaram-se 42 (59 por cento) CGs do tipo intestinal (Cal), 17 (24 por cento) difusos (CaD) e 12 (17 por cento) não foram classificáveis. A GCA e a MI foram mais intensas no Cal do que no CaD (p = 0,02; p = 0,004). Observaram-se focos de Ml dos tipos I, II e III em 21 Cal (50 por cento), enquanto que 5/17 (29 por cento) CaD com MI apresentavam focos de MI de tipos I e II. A MI do tipo III foi diagnosticada em 21 Cal(50 por cento) e em seis CaD (35 por cento) (p = 0,04); nas áreas peritumorais com MI, a do tipo III foi detectada em 13/34 (38 por cento) Cal e 3/10 (30 por cento) CaD. Houve correlação entre a intensidade da MI e o tipo da lesão (p = 0,005), observando-se MI de tipo III predominantemente quando as lesões eram de intensidade moderada a acentuada. Conclusões: A MI de tipo III pode ser considerada um marcador da intensidade do processo metaplásico. Sua presença em 50 por cento dos Cal limita seu papel como lesão de risco e reforça a hipótese da existência de diversas vias carcinogênicas para o CG

Effect of thyroid hormone on the alcohol dehydrogenase activities in rat tissues

The effects of thyroid hormone on hepatic and gastric alcohol dehydrogenase (ADH) activities (nM of NADH/min/mg of cytosolic protein) have been investigated in male Sprague Dawley rats treated with thyroxine (1 mg/kg, po) for 14 days. Whereas hepatic ADH activity in thyroxine-treated rats decreased by 61.3% of control rats (26.4 vs 43.2, p<0.001), gastric ADH activity increased by 262.9% of control rats (4.9 vs 1.9, p<0.001). As for the activities of the lung and kidney, thyroxine treatment did not produce any statistically significant changes. These data suggest that thyrotoxicosis causes a decrease of hepatic alcohol metabolism, and that the increase of gastric ADH activity in thyrotoxic rats can partly restore the first-pass metabolism of ethanol.

Transporte na+ -dependiente de l- alanina en glándulas gástricas aisladas de ratas alimentadas con dieta normal y pobre en proteína kwashiorkor / Na+ dependent transport of l- alanine by isolated gastric glands from rats fed with a normal- protein or a low protein diet kwashiorkor

El objetivo del presente trabajo fue estudiar y comparar el transporte sodio-dependiente de l-alanina en la membrana basolateral de las glándulas gástricas aisladas de ratas alimentadas tanto con una dieta normal y otras con una dieta pobre en proteina (kwashiorkor). Se observóun componente saturable del transporte sodio-dependiente de alanina en ambos grupos de animales, siendo el transporte bastante mayor en las glándulas gástricas de las ratas desnutridas. Tal incremento se debió a un significativo aumento (p< 0.001) en la velocidad máxima del transporte de alanina (control= 3.49 ñ 0.23 nmol/mg de proteína en 20 segundos; Kwashiorkor = 11,86 ñ 0.35 nmol/mg proteína en 20 segundos), mientras que la Km aparente del transporte fue similar en los dos grupos de ratas. Se concluye que la desnutrición está asociada con un incremento en el número y/o actividad intrínseca de los transportadores sodio-dependientes de alanina

Changes of gastroduodenal peroxidase activity of rats by cerebellar modulation.

The effect of vestibulo-cerebellar lesion and its stimulation by rotation on gastric and duodenal peroxidase activity of rats was studied. Vestibulocerebellar lesion by kainic acid produced gastroduodenal ulceration and peroxidase activity of these tissues were decreased. Mucosal thickness of gastric and duodenal tissue were also decreased. It was observed that when vestibulo-cerebellar lesioned rats were subjected to vestibular stimulation, the peroxidase activity was increased together with increased mucosal thickness of gastric and duodenal tissue. At the same time, it was noted that the severity of ulceration was decreased. We conclude that the study of peroxidase activity is a sensitive and potentially useful estimate of gastric and duodenal injury produced by cerebellar lesion that can be valuable in assessing ulcerogenesis and healing.

Papel del calcio en la regulacion de la oxidacion del oxoglutarato en la mucosa gastrica del conejo / Role of calcium in regulation of oxoglutarate oxidation in the rabbit gastric mucosa

The stimulation of the oxyntic cell by gastric secretagogues is associated to the activation of oxidative metabolism. The mechanisms of this activation are not exactly known. In the present work, we investigated the possible direct effect of Ca2+ on both oxoglutarate oxidation in rabbit gastric glands and oxoglutarate dehydrogenase activity (OGDH) is isolated gastric mitochondria. Both carbachol and Ca2+ ionophores +(A23187 and ionomycin) significantly stimulated oxoglutarate oxidation in a dose-dependent manner. This effect was only observed in the presence of low substrate concentrations. BAPTA-AM, an intracellular calcium chelator, significantly inhibited the rate of oxoglutarate oxidation. OGDH activity was stimulated by physiological concentrations of Ca2+ in a dose-depentent manner. This effect was reduced by ruthenium red, an inhibitor of mitochondrial Ca2+ uptake, and it was additionally increased by spermine, a stimulant of Ca2+ influx to the mitochondria. Results support the hypothesis that Ca2+ plays a direct role in the activation of oxidative metabolism in the oxyntic cell

Rol de la oxido nitrico sintetasa inducible en el dano agudo de la mucosa gastrica en el estres, en ratas / Role of the inducible nitric oxide synthase in the acute gastric mucosal damage in the stress, in rats

En diferentes grupos de ratas Wistar, sometidas a estrés por inmovilización e inmersión en agua a 18 graus Celsius durante 6hs, fue estudiado el rol del óxido nítrico (NO) en su fisiopatología; donde fueron usados agonistas y antagonistas de las isoenzimas NO Sintetasa Constitutiva (NOSc) y de la NO Sintetasa inducible (NOSi). Como agonistas de la NOSc se usaron dosis de L-arginina y como antagonistas de la L-NMMA. Se comprobó que la sobredosis de L-arginina agravó las lesiones agudas gastricas. Como agonistas de la NOSi se usó la NMDA y como antagonista la dexametasona y la aminoguanidina. Se comprobó que el agonista agravó las lesiones g stricas del estrés, en contraste, tanto dexametasona como aminoguanidina dieron una marcada protección de la mucosa gastrica. Se concluyó que la producción del NO dado por la NOSi, desempeña un papel preponderante en la fisiopatologia de las lesiones agudas gastricas en el estrés.

Efectos de la administración de cortisol sobre la actividad proteolítica de la mucosa gástrica en ratas desnutridas / Effects of cortisol administration on the proteolytic activity of the gastric mucosa in undernourished rats

Se estudió el efecto de la administración de cortisol a ratas desnutridas sobre la actividad proteolítica de la mucosa gástrica. Se restringió la administración a ratas al 60 % de sus requerimientos durante 4 semanas. Para la determinación de la actividad proteolítica se utilizó el método clásico de Anson y Mirsky, con algunas modoficaciones realizadas en nuestro laboratorio. El tratamiento con cortisol produjo disminución en dicha actividad en los animales desnutridos, no así en el grupo control. Se resalta la importancia del hecho de que el efecto de la administración de cortisol sobre la actividad proteolítica de la mucosa gástrica en ratas está en dependencia del estado nutricional del organismo

Catepsina D de próstata humana / Cathepsin D from human prostate

En este trabajo se ha desarrollado una metódica simple que ha permitido la obtención de catepsina D de próstata humana en cantidades apreciables para estudios enzimáticos y químicos, empleando cromatografías combinadas de intercambio en DEAE celulosa y cromatoenfoque en gel PBE-94. La síntesis química de un nuevo sustrato sintético permitió comparar la actividad hidrolítica de la catepsina D con las gastricsinas de próstata y líquido seminal humano, así como con pepsina y gastricsina de mucosa gástrica. La actividad de la catepsina prostática sobre el sustrato sintético N-acetil-L-fenilalanil-L-diyodotirosil-L-valina metil éster (APDTV) fué similar a la de las gastricsinas y mucho mayor con respecto a la pepsina. Las relaciones ácido glutámico/ácido aspártico (Glu/Asp) y leucina/isoleucina (Leu/Ile) de la catepsina D son semejantes a las presentes en las gastricsinas y no en las pepsinas, en cuyo caso estos aminoácidos se encuentran en una razón inversa