Expression of metalloproteinase-9 in patients with mild and severe forms of gastroesophageal reflux disease.

BACKGROUND: Gastroesophageal reflux disease develops when the stomach contents causes troublesome symptoms and complications. Mild forms are non-erosive and erosive esophagitis, and severe forms are Barrett's esophagus and Esophageal adenocarcinoma. Matrix metalloproteinases are endopeptidases that can degrade components of the extracellular matrix, they play an important role in tumor invasion as well as in metastasis. OBJECTIVE: To correlate the expression of metalloproteinase 9 (MMP-9) in esophageal biopsies from patients with mild and severe forms of Gastroesophageal reflux disease. METHOD: Cross-sectional study. The expression of MMP-9 was determined in biopsies of esophageal tissue of patients with mild and severe GRD. The included variables were age, sex, diagnosis, smoking and alcoholic habits, body mass index (BMI) and expression of MMP-9. Descriptive statistics was performed, Kappa for concordance in diagnosis as well as X2. RESULTS: There were 50 patients, 32 (64%) men and 18 (36%) women, mean age 52.13 ± 14.75 years of age. 12 (24%) with smoking and 7 (14%) with alcoholism. Average BMI was 26.71 ± 4.07 kg/m2 (15 to 33); 40 (80%) with obesity. The inter observer concordance for histopathological diagnosis was 1.0 and 0.84 for esophagitis degrees. 27 (54%) patients had esophagitis, 16 (32%) Barrett's esophagus and 7 (14%) esophageal cancer. There was expression of MMP-9 in four patients with esophagitis, five with Barrett's esophagus and five with esophageal cancer. Statistical significance was found between the expression of MMP-9 and smoking (p = 0.011) and histopathological diagnosis (p = 0.052). CONCLUSIONS: The expression of MMP-9 is most common in severe forms compared to the mild forms of GRD.

ANTECEDENTES: La enfermedad por reflujo gastroesofágico (ERGE) se desarrolla cuando el contenido estomacal ocasiona síntomas molestos o complicaciones. Las formas leves son esofagitis no erosiva y erosiva; las graves, esófago de Barrett y adenocarcinoma esofágico. Las metaloproteinasas de la matriz degradan componentes de la matriz extracelular, y tienen un papel importante en la invasión tumoral y la metástasis. OBJETIVO: Relacionar la expresión de la metaloproteinasa-9 (MMP-9) en biopsias esofágicas de pacientes con formas leves y graves de ERGE. MÉTODO: Estudio transversal. Se determinó la expresión de MMP-9 en biopsias esofágicas de pacientes con ERGE grave y leve. Las variables fueron edad, sexo, diagnóstico, tabaquismo, alcoholismo, índice de masa corporal (IMC) y expresión de MMP-9. Se realizó estadística descriptiva, concordancia para el diagnóstico y prueba de ji al cuadrado. RESULTADOS: 50 pacientes, 32 (64%) hombres y 18 (36%) mujeres, con edad media de 52.13 ± 14.75 años. Doce (24%) fumadores y 7 (14%) con alcoholismo. El IMC promedio fue de 26.71 ± 4.07 kg/m2 (rango: 15-33); 40 (80%) eran obesos. La concordancia entre observadores para el diagnóstico histopatológico fue de 1.0, y de 0.84 para esofagitis. Veintisiete (54%) tuvieron esofagitis, 16 (32%) esófago de Barrett y 7 (14%) cáncer de esófago. Hubo expresión de MMP-9 en cuatro pacientes con esofagitis, cinco con esófago de Barrett y cinco con cáncer esofágico. Encontramos diferencia estadísticamente significativa entre la expresión de MMP-9 y el tabaquismo (p = 0.011) y el diagnóstico histopatológico (p = 0.052). CONCLUSIONES: La expresión de MMP-9 es más frecuente en las formas graves que en las leves de ERGE.

A sequence variant in the phospholipase C epsilon C2 domain is associated with esophageal carcinoma and esophagitis.

A single-nucleotide polymorphism (rs2274223: A5780G:His1927Arg) in the phospholipase C epsilon gene (PLCϵ) was recently identified as a susceptibility locus for esophageal cancer in Chinese subjects. To determine the underlying mechanisms of PLCϵ and this SNP in esophageal carcinogenesis, we analyzed PLCϵ genotypes, expression, and their correlation in esophageal cancer cell lines, non-transformed esophageal cells, 58 esophageal squamous cell carcinomas and 10,614 non-cancer subjects from China. We found that the G allele (AG or GG) was associated with increased PLCϵ mRNA and protein expression in esophageal cancer tissues and in esophageal cancer cell lines. G allele was also associated with higher enzyme activity, which might be associated with increased protein expression. Quantitative analysis of the C2 domain sequences revealed that A:G allelic imbalance was strongly linked to esophageal malignancy. Moreover, the analysis of 10,614 non-cancer subjects demonstrated that the G allele was strongly associated with moderate to severe esophagitis in the subjects from the high-incidence areas of China (OR 6.03, 95% CI 1.59-22.9 in high-incidence area vs. OR 0.74, 95% CI 0.33-1.64 in low-incidence area; P = 0.008). In conclusion, the PLCϵ gene, particularly the 5780G allele, might play a pivotal role in esophageal carcinogenesis via upregulating PLCϵ mRNA, protein, and enzyme activity, and augmenting inflammatory process in esophageal epithelium. Thus, 5780G allele may constitute a promising biomarker for esophageal squamous cell carcinoma risk stratification, early detection, and progression prediction.

Indomethacin but not a selective cyclooxygenase-2 inhibitor inhibits esophageal adenocarcinogenesis in rats.

AIM: To evaluate the effects of indomethacin [dual cyclooxygenase (COX)-1/COX-2 inhibitor] and 3-(3,4-difluorophenyl)-4-(4-(methylsulfonyl) phenyl)-2-(5H)-furanone (MF-tricyclic) (COX-2 selective inhibitor) in a rat experimental model of Barrett's esophagus and esophageal adenocarcinoma. METHODS: A total of 112 surviving post-surgery rats were randomly divided into three groups: the control group (n = 48), which did not receive any treatment; the indomethacin group (n = 32), which were given 2 mg/kg per day of the COX-1/COX-2 inhibitor; and the MF-tricyclic group (n = 32), which received 10 mg/kg per day of the selective COX-2 inhibitor. Randomly selected rats were killed either 8 wk or 16 wk after surgery. The timing of the deaths was in accordance with a previous study performed in our group. Only rats that were killed at the times designated by the protocol were included in the study. We then assessed the histology and prostaglandin E2 (PGE2) expression levels in the rat esophagi. An additional group of eight animals that did not undergo esophagojejunostomy were included in order to obtain normal esophageal tissue as a control. RESULTS: Compared to a control group with no treatment (vehicle-treated rats), indomethacin treatment was associated with decreases in ulcerated esophageal mucosa (16% vs 35% and 14% vs 17%, 2 mo and 4 mo after surgery, respectively; P = 0.021), length of intestinal metaplasia in continuity with anastomosis (2 ± 1.17 mm vs 2.29 ± 0.75 mm and 1.25 ± 0.42 mm vs 3.5 ± 1.54 mm, 2 mo and 4 mo after surgery, respectively; P = 0.007), presence of intestinal metaplasia beyond anastomosis (20% vs 71.4% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P = 0.009), severity of dysplasia (0% vs 71.4% and 20% vs 85.7% high-grade dysplasia, 2 mo and 4 mo after surgery, respectively; P = 0.002), and adenocarcinoma incidence (0% vs 57.1% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P < 0.0001). Treatment with the selective COX-2 inhibitor, MF-tricyclic, did not prevent development of intestinal metaplasia or adenocarcinoma. In parallel, we observed a significant decrease in PGE2 levels in indomethacin-treated rats, but not in those treated with MF-tricyclic, at both 2 mo and 4 mo. Compared to control rats that did not undergo surgery (68 ± 8 ng/g, P = 0.0022 Kruskal-Wallis test) there was a significant increase in PGE2 levels in the esophageal tissue of the rats that underwent surgery either 2 mo (1332 ± 656 ng/g) or 4 mo (1121 ± 1015 ng/g) after esophagojejunostomy. However, no differences were found when esophageal PGE2 levels were compared 2 mo vs 4 mo post-esophagojejunostomy. At both the 2- and 4-mo timepoints, we observed a significant decrease in PGE2 levels in indomethacin-treated rat esophagi compared to those in either the control or MF-tricyclic groups (P = 0.049 and P = 0.017, respectively). No differences in PGE2 levels were found when we compared levels in rats treated with MF-tricyclic to not-treated rats. CONCLUSION: In this rat model of gastrointestinal reflux, indomethacin was associated with a decrease in the severity of esophagitis and reduced development of esophageal intestinal metaplasia and adenocarcinoma.

Analysing the role of COX-2 in acute oesophagitis and in melatonin-exerted protection against experimental reflux oesophagitis in rats.

OBJECTIVES: Cyclooxygenase(COX)-2 is implicated in variety of pathophysiological processes, although its role in acute reflux oesophagitis is debatable. This study was designed to evaluate the role of COX-2 during oesophagitis and in melatonin-elicited protection in rats. METHODS: Reflux oesophagitis was induced in rats by ligating the pyloric end and the limiting ridge of the stomach for 5 h. Celecoxib (COX-2 blocker; 10 mg/kg), 16,16-dimethyl prostaglandinE(2) (dmPGE(2); a synthetic analogue of PGE(2) ; 10 µg/kg), melatonin (20 and 40 mg/kg) and omeprazole (10 mg/kg) were given intra-peritoneally 45 min before induction of oesophagitis in rats. Alterations in COX-1 and 2 gene expression and protein levels level were analysed via RT-PCR and Western blotting, respectively. Mucosal PGE(2) level and myeloperoxidase (MPO) activity were measured using an enzyme immunoassay (EIA) kit and spectrophotometrically, respectively. KEY FINDINGS: COX-2 over-expression during reflux oesophagitis promotes inflammation of the oesophagus as celecoxib pretreatment significantly reduced tissue damage and MPO activity in rats with reflux oesophagitis (RE-rats). By contrast, dmPGE(2) pretreatment significantly exacerbated tissue injury and simultaneously increased COX-2 expression, PGE(2) levels and MPO activity in RE-rats. Further, melatonin pretreatment significantly reduced the tissue injury, COX-2 over-expression, PGE(2) level and MPO activity in RE-rats. Melatonin offered more potent suppression of COX-2, PGE(2) and MPO activity than the proton-pump inhibitor omeprazole; however, both reduced the lesion injury to a similar extent. Melatonin at a dose of 20 mg/kg failed to inhibit significantly the dmPGE(2) -induced tissue damage, COX-2 expression, PGE(2) level and MPO activity in RE-rats while at a higher dose of 40 mg/kg it significantly attenuated these changes. CONCLUSION: Our results suggest that COX-2 plays an important pro-inflammatory role during acute reflux oesophagitis in rats and its inhibition contributes significantly to melatonin-exerted protection against reflux oesophagitis.

Aberrant expression of epidermal growth factor receptor and its interaction with protein kinase C δ in inflammation associated neoplastic transformation of human esophageal epithelium in high risk populations.

BACKGROUND AND AIM: Esophageal cancer is the second most common cancer among Indian males and is mostly associated with tobacco smoking and alcohol consumption. Epidermal growth factor receptor (EGFR) is a member of Type I tyrosine kinases. Its activation causes the docking of various proteins in its cytosolic tail. In the present study we have analyzed the expression pattern of EGFR, protein kinase C δ (PKCδ), tumor necrosis factor-α (TNF-α), nuclear factor κB (NFκB) and the interactions between EGFR and PKCδ in various pathological conditions. METHODS: Human esophageal biopsies were obtained from 93 patients with a past history of smoking and alcohol consumption: 20 showed normal mucosa, 40 with dysplasia and 33 squamous cell carcinoma (SCC). These pathological conditions were analyzed immunohistochemically for the presence of EGFR expression and then subsequently analyzed using immunoblot and immunoprecipitation. RESULTS: A statistically significant difference of EGFR overexpression was found between low- and high-grade dysplasia and carcinoma (χ² = 3.3, χ² = 3.42: P = 0.07, 0.33). A statistical significance was observed between dysplasia and SCC and in all histopathological types (χ² = 4, χ² = 4.9; P < 0.05, P = 0.18 and χ² = 26.3, 26.6; P < 0.001). EGFR tyrosine phosphorylation and its association with PKCδ was significantly higher in all histopathological types with χ² = 7.965; P < 0.05 and 4.0830; P = 0.2530. CONCLUSION: Altogether, our findings reveal that the activation of EGFR and its subsequent interaction with PKCδ under inflammatory conditions might positively be attributed to the transformation of normal esophageal epithelia to SCC, which could explain ongoing inflammation in normal mucosa in a population prone to smoking and alcoholism.

Expression of ki-67 antigen and caspase-3 protein in benign lesions and esophageal carcinoma.

BACKGROUND: The present study aimed to evaluate apoptosis and cell proliferation alterations in esophageal benign lesions in comparison to esophageal carcinomas. MATERIALS AND METHODS: Immunohistochemistry was performed for caspase-3 protein (CPP32) and Ki-67 antigen expression in the esophageal mucosa from patients with Chagas disease (CD) with and without megaesophagus (CM), chronic esophagitis (CE), esophageal carcinoma (ESCC) and in normal mucosa (NM). RESULTS: The Ki-67 labeling index (LI) was similar in all groups (range: 30%-48%), having no statistically significant difference among the groups. Positive CPP32 immunostaining was observed with similar frequency in the CD (30.8%), CM (30.4%) and CE (34.8%) groups, but it was increased in the ESCC group (55.5%); however, it was not statistically different from the other groups. No associations among the levels of CPP32 and Ki-67 expression were observed in the various groups, neither among parameters such as age, gender or alcohol and tobacco consumption. CONCLUSION: There were no evident changes in cell proliferation and apoptosis in benign lesions studied.

[Lipid peroxidation and antioxidant protection in patients with different variants of gastro-esophageal reflux disease].

UNLABELLED: AIM. To study features of lipids peroxide oxidation and function of antioxidant protection in patients with various variants of gastro-esophageal reflux disease (GERD). MATERIAL AND METHODS: 120 patients with GERD and 20 healthy persons were examinated. Diene conjugates, ketodienes, connected trienes, concentration of intermediants of peroxide oxidation, catalase activity and general antioxidizing activity index were investigated in blood serum and esophageal biopsy specimens by biochemical methods. RESULTS: The level of peroxide oxidation products in esophageal biopsy specimens in esophagitis and complicated GERD was 1.8-4.5 times higher then in control group. The level of catalase activity and general antioxidizing activity was 2-5 times lower in patients with the pathology in comparison to healthy persons. CONCLUSION: Patients with GERD had activation of lipids peroxide oxidation accompanied by deficiency of antioxidants in esophageal mucosa and blood serum proportionally to esophagus damage degree.

Marked deposition of eosinophil-derived neurotoxin in adult patients with eosinophilic esophagitis.

OBJECTIVES: Eosinophilic esophagitis (EoE) is characterized by infiltration of eosinophils into esophageal epithelium. Blood levels of an eosinophil granule protein, eosinophil-derived neurotoxin (EDN), have been proposed as a biomarker for EoE. However, information regarding localization of EDN in the diseased tissues has not been available. The goal of this study was to evaluate the magnitude and distribution of EDN deposition in tissue specimens from the esophagus of EoE patients. METHODS: We studied specimens from 10 adult EoE patients and eight histologically normal controls (three under age 17). Sections from mid-esophageal biopsy specimens were stained for EDN by immunofluorescence, using a polyclonal rabbit antibody to EDN. Cellular staining (i.e., infiltration of intact eosinophils) and extracellular staining (i.e., deposition of released EDN) were scored in a blinded manner on an established 7-point scale. RESULTS: Esophageal biopsy specimens from histologically normal controls showed no or few intact eosinophils and no or minimal extracellular EDN deposition. In contrast, EDN staining was clearly observed in specimens from all EoE patients. In some EoE patients, marked extracellular EDN deposition was observed despite relatively small numbers of intact eosinophils. Overall, there was no correlation between the eosinophil infiltration and the extracellular EDN staining scores. CONCLUSIONS: Marked tissue deposition of extracellular EDN is present in the esophagus of EoE patients. Tissue eosinophil counts may underestimate how extensively eosinophils are involved, particularly in individuals with marked eosinophil degranulation. Evaluation of EDN staining in esophageal biopsy specimens may be useful to diagnose and manage patients with EoE.

Evaluation of fatty acid synthase expression in oesophageal mucosa of patients with oesophagitis, Barrett's oesophagus and adenocarcinoma.

BACKGROUND AND AIM: To evaluate the expression of fatty acid synthase (FAS) in the oesophagitis-Barrett's oesophagus-oesophageal adenocarcinoma sequence compared with p53 and Ki67 expressions, retained for a long time reliable markers of oesophageal cells biological behaviour. METHODS: In Barrett's oesophagus, oesophagitis and oesophageal adenocarcinoma patients, biopsies were taken from pathologic sites of the mucosa for histological and immuno-histochemical detection of FAS, p53 and Ki67. FAS expression was positive, when a strong granular cytoplasmic staining was observed in oesophageal cells. Ki67 and p53 was defined positive, when nuclear staining was clearly detected at 10x magnification. RESULTS: A mild expression of FAS was found in 39% of patients with oesophagitis. The amount of FAS expression increased up to 70% in Barrett's oesophagus while this was present in all patients with oesophageal adenocarcinoma (p = 0.0001). In Barrett's oesophagus, p53 was mildly or intensely expressed in 77% and in 15% of cases, respectively, and mildly or intensely expressed in 33% and 67% of patients with oesophageal adenocarcinoma, respectively, (p = 0.0001). Ki67 was mildly expressed in 17% of oesophagitis cases and was absent in the majority of cases. In Barrett's oesophagus, a mild Ki67 expression was present in 46% of cases, and in oesophageal adenocarcinoma it was present prevalently in intense form (67%; p = 0.0001). CONCLUSIONS: The over-expression of p53, Ki67 and FAS in otherwise similar morphological groups may be useful to stratify patients into selected prognostic subgroups in order to achieve better clinical approaches.

Role of pancreatic trypsin in chronic esophagitis induced by gastroduodenal reflux in rats.

BACKGROUND: Reflux of the duodenal contents with gastric acid has been reported to contribute to the development of esophageal mucosal damage and inflammation. Recent studies show that pancreatic trypsin can stimulate the production of inflammatory mediators, including chemokines and prostaglandins from human esophageal epithelial cells in vitro. The aim of the present study was to investigate the role of pancreatic trypsin in the pathogenesis of chronic esophageal inflammation induced by gastroduodenal reflux in rats. METHODS: Esophagogastroduodenal anastomosis was carried out in male Wistar rats by anastomosing the jejunum to the gastroesophageal junction under diethyl ether inhalation anesthesia. The animals undergoing surgery were treated with the control diet, rabeprazole sodium, nizatidine, ecabet sodium, camostat mesilate (CMM), ONO-1714, a specific inducible nitric oxide synthase (iNOS) inhibitor, or meloxicam, a selective cyclooxygenase-2 (COX-2) inhibitor. Esophageal injury was evaluated by macroscopic and microscopic findings, and mRNA expression for CINC-1, COX-2, and iNOS was determined by real-time polymerase chain reaction (PCR). Trypsin activity within the esophageal lumen was measured 2 weeks after surgery, and the expression of protease-activated receptor (PAR)-1 and -2 was confirmed by reverse transcription (RT)-PCR. RESULTS: At 8 weeks after surgery, gastroduodenal reflux induced esophageal erosions and ulcer formation as well as marked thickening of the esophageal wall. Histological study showed an increase of thickness of the esophageal mucosa, hyperplasia of the epidermis and basal cells, ulcer formation, and marked infiltration of inflammatory cells. The macroscopic ulcer score and histological ulcer length were significantly reduced by treatment with rabeprazole or CMM but not by nizatidine or ecabet sodium, compared with each control. Rabeprazole, nizatidine, or ecabet sodium did not affect the severity of mucosal hyperplastic scores or histological parameters in esophagitis. In contrast, the CMM group showed a significant decrease in the mucosal hyperplastic and inflammatory scores. The enhanced expression of CINC-1, COX-2, and iNOS mRNA in the control group was also markedly inhibited in the CMM-treated group. ONO-1714 or meloxicam treatment significantly reduced the macroscopic scores of ulcer and hyperplasia. The trypsin activity in the esophageal lumen was significantly increased in the control diet group, and this increase was significantly inhibited in the CMM-treated group. The expression of PAR-1 and -2 mRNA was confirmed in rat esophageal epithelium. CONCLUSIONS: With this model, we have demonstrated that CMM significantly reduces inflammation and hyperplasia in the esophageal mucosa. These results indicate that trypsin, which is primarily inhibited by CMM, plays an important role in the mucosal damage induced by gastroduodenal reflux and that it can be a therapeutic target in patients with gastroduodenal reflux esophagitis.

DNA methylation in esophageal diseases including cancer: special reference to hMLH1 gene promoter status.

AIMS AND BACKGROUND: Chronic inflammation leading to malignancy in the esophagus may be due to errors in mismatch repair (MMR) genes such as hMLH1. Promoter hypermethylation has been suggested as the main cause of hMLH1 silencing. In this study we assessed hMLH1 promoter hypermethylation in a range of esophageal diseases. Further, we evaluated the role of factors affecting the methylation cycle: (1) methylenetetrahydrofolate reductase (MTHFR) C677T mutation and (2) serum homocysteine levels. METHODS: We endoscopically and histologically categorized 124 paired tissue and blood samples from patients into cancer, precancer, reflux esophagitis, other inflammatory esophagitis and controls (endoscopically normal). Restriction enzyme-based methylation analysis was carried out to assess hMLH1 promoter hypermethylation. RESULTS AND CONCLUSIONS: hMLH1 promoter hypermethylation in tissue was seen in 63.5% of patients with cancer and 53.8% of those with precancer, which was significantly increased when compared with controls (P < 0.001). There appears to be an increasing degree of hMLH1 hypermethylation with disease progression. Patients with gastroesophageal reflux disease (GERD) showed a high degree of hMLH1 hypermethylation (88.8%), indicating that local environment due to reflux may be promoting hypermethylation. We suggest that GERD is a progressive condition with an increased risk for developing into cancer. Only 14.5% of cases exhibited hypermethylation both in tissue and blood. Hence, we conclude that hMLH1 promoter hypermethylation is a tissue-specific change in the esophagus and blood testing cannot be used as a noninvasive tool to assess it. DNA methylation is dependent on the methylation cycle; MTHFR is a major enzyme in this pathway. MTHFR mutations did not correlate with hypermethylation or clinical pathology (P > 0.5). Elevated homocysteine levels, independent of MTHFR mutation, correlated significantly with hMLH1 hypermethylation in tissue (P < 0.005). Our study shows that hMLH1 hypermethylation in tissue may be the primary event caused by endogenous/exogenous factors in esophageal diseases, aiding disease progression.

A COX-2 inhibitor prevents the esophageal inflammation-metaplasia-adenocarcinoma sequence in rats.

Barrett's esophagus (BE) and esophageal adenocarcinoma (ADC) is associated with reflux of duodenal contents. Cyclooxygenase (COX)-2 is over-expressed in BE and ADC, and supposedly contributes to esophageal carcinogenesis. The aim of this study is to investigate what effect a COX-2 inhibitor has on esophageal adenocarcinogenesis in rats. A series of 90 rats underwent a duodenoesophageal reflux procedure and were divided into 2 groups. One group was given commercial chow (control group), and the other was given experimental chow containing celecoxib (celecoxib group). The animals were sacrificed sequentially, at the 10th, 20th, 30th and, finally, 40th week after surgery, and their esophagi were examined. In the control group, esophagitis, columnar-lined epithelium (CLE) and ADC were first observed at the 10th week, 20th week and 30th week, respectively. Their incidences sequentially increased and at the 40th week reached 100, 89 and 47%, respectively. In the celecoxib group, the esophagitis was mild and the incidence of CLE was significantly lower at each week (P < 0.001), compared with the control group, and ADC was not observed throughout the experiment (P < 0.05). COX-2 expression was observed predominantly in the stroma of inflamed esophageal epithelia, and up-regulated at the 10th and 20th week (P < 0.05, respectively). PGE2 level and proliferative activity were also up-regulated in both groups, but they were lower in the celecoxib group than in the control group (P < 0.05). Apoptosis was observed to increase with celecoxib treatment (P < 0.05). Celecoxib is effective in preventing CLE and ADC by suppressing esophagitis in rats.

Effects of nitric oxide synthase inhibitor to esophagus in a feline esophagitis model.

The present study explores the effects of nitric oxide synthase inhibitor on esophageal motility in a feline model with esophagitis. Perfusion of the esophagus with acid produced inflammatory changes of esophageal mucosa. The esophageal motility was measured before and after the perfusion. One group of cats was given nitric oxide inhibitor orally at the same time as the perfusion of acid. The control group was given water instead. Esophagitis impairs the motility of the esophagus. However, the esophageal motility of the cats that were given nitric oxide synthase inhibitor decreased less than that of the control group. The results suggested that during esophagitis there is an alteration of the nitric oxide synthase/nitric oxide pathway in the esophagus, which may be one of the important mechanisms of esophageal motility dysfunction.

COX-2 inhibition in esophagitis, Barrett's esophagus and esophageal cancer.

There is extensive evidence that cyclooxygenase-2 (COX-2) plays a significant role in the process of carcinogenesis in different tumors. Although most of these evidences derive from studies in colorectal cancer, data obtained from recent studies strongly suggest that COX-2 might play an important role in the neoplastic transformation of esophageal epithelium. NSAIDs use is associated with a reduction of the risk of developing esophageal cancer, including adenocarcinoma. Up-regulation of COX-2 has been reported in different stages of the carcinogenic sequence leading to esophageal adenocarcinoma. Treatment with selective COX-2 inhibitors has been shown to reduce the damage induced by acid and pepsin in the esophageal mucosa of rabbits, the incidence of tumors in an animal model of esophageal adenocarcinoma and to decrease proliferation and induce apoptosis in both Barrett's epithelial and adenocarcinoma cells. The first clinical study has shown that selective inhibition of COX-2 is followed by a significant decrease of cell proliferation in human Barrett's metaplasia. Clinical trials have begun in order to assess the efficacy of selective COX-2 inhibitors to prevent the progression of Barrett's esophagus to adenocarcinoma. Bile salts and acid are likely to early induce COX-2 in this sequence, although other factors, such as proinflammatory cytokines, inducible nitric oxide synthase and growth factors such as TGF-beta, are potential COX-2 inducers in the esophagus. Further studies are necessary in order to better understand factors involved in COX-2 up-regulation and mechanisms of COX-2 associated tumorigenesis in the esophagus.

Selective COX-2 inhibition is associated with decreased mucosal damage induced by acid and pepsin in rabbit esophagitis.

OBJECTIVE: To evaluate the effects of COX-1 and/or COX-2 inhibition in a model of chronic esophagitis in rabbits. METHODS: Both high- and low-grade esophagitis were induced in rabbits by the perfusion of acidified pepsin. Rabbits were treated with either a selective COX-2 inhibitor (DFU[3-(3-Fluorophenyl)-4-(4-Methanesulfonyl)-5,5-Dimethyl-5H-Furan-2-One];30 mg/Kg/day), a nonspecific COX inhibitor (indomethacin; 2 mg/Kg/day), or a COX-1 preferential inhibitor (piroxicam; 2 mg/Kg/12 h). RESULTS: Prostaglandins are derived from COX-1 activity in the normal esophagus. Both low- and high-grade esophagitis are associated with a progressive increase of COX activity, which is partially dependent on the COX-2 isoform. DFU reduced muscosal damage in both models of esophagitis. However, indomethacin did not affect significantly mucosal damage, and piroxicam increased damage in low-grade esophagitis. CONCLUSIONS: COX-1 activity is constitutive in the rabbit esophageal mucosa, but both COX-2 and COX-1 activity are increased under the impact of acidified pepsin. Treatment with the COX-2 inhibitor DFU is associated with improvement of mucosal damage, which may have therapeutic implications.

Esophageal dysmotility and the change of synthesis of nitric oxide in a feline esophagitis model.

The present study explores the changes of nitric oxide synthesis and esophageal dysmotility in a feline model of esophagitis. Perfusion of the esophagus with acid produced inflammatory changes of esophageal mucosa. The esophageal motility was measured before and after the perfusion. The nitric oxide synthase activity, the l-arginine uptake, and the content of cyclic guanine monophosphate of the muscle and the mucous membrane were determined and the NADPH-diaphorase was stained. Esophagitis impairs the motility of the esophagus. The nitric oxide synthase activity, the content of cyclic guanine monophosphate, the NADPH-diaphorase stain and the maximum velocity of l-arginine uptake of lower esophageal sphincter of the cats in the acid perfusion group were higher than those of the control group. The maximum velocity of l-arginine transport and the content of cyclic guanine monophosphate of the mucosa in the acid perfusion group were lower than those of the control group. The results suggested that during esophagitis there is an alteration of the l-arginine/nitric oxide synthase/nitric oxide pathway in the esophagus, which may be one of the important mechanisms of esophageal motility dysfunction.

[Role of endogenous cholinergic nerve in esophageal dysmotility with reflux esophagitis].

OBJECTIVE: To study the role of endogenous cholinergic nerve in esophageal dysmotility with reflux esophagitis in a feline model. METHODS: In 16 healthy cats under ketamine anesthesia (20 mg/kg), the abdominal parts of lower esophageal sphincter were cut open to establish the animal model for reflux esophagitis; esophageal motility was measured respectively preoperation and post-esophagitis. The activities of choline acetyltransferase (CHAT) and acetylcholinesterase(ACHE) in medial and distal esophageal body muscle was measured respectively with spectrophotometry, and compared to the normal cats(n = 8). RESULTS: Reflux esophagitis can make distal esophageal peristaltic amplitude decrease, the distal esophageal peristaltic amplitude of cats with reflux esophagitis [above LES 1 cm: (22.65 +/- 16.53) mm Hg; above LES 3 cm:(39.94 +/- 14.78) mm Hg, P < 0.0001] was significantly lower than that of normal cats [above LES 1 cm: (63.71 +/- 21.34) mm Hg; above LES 3 cm: (73.65 +/- 23.42) mm Hg] and the conducting velocity of distal esophagus was slower than that of normal cats [(1.04 +/- 0.36) cm/s vs (1.39 +/- 0.46) cm/s, P < 0.05]. In the esophagus of reflux esophagitis group, CHAT activity was lower in the model, especially in the distal part [(81.01 +/- 22.03) U/g vs (230.13 +/- 30.10) U/g, P < 0.0001] and ACHE activity remains unchanged. CONCLUSION: CHAT activity and pressure level were lower in the distal esophagus with reflux esophagitis compared to the normal cats. This study supported that reflux esophagitis can results in dysmotility of the distal esophagus and the abnormality of endogenous cholinergic innervation is one of the important mechanisms as far as the disorder of esophageal movement in reflux esophagitis.

Differential activation of a Candida albicans virulence gene family during infection.

The yeast Candida albicans is a harmless commensal in most healthy people, but it causes superficial as well as life-threatening systemic infections in immunocompromised patients. C. albicans can colonize or infect virtually all body sites because of its high adaptability to different host niches, which involves the activation of appropriate sets of genes in response to complex environmental signals. We have used an in vivo expression technology that is based on genetic recombination as a reporter of gene expression to monitor the differential activation of individual members of a gene family encoding secreted aspartic proteinases (Saps), which have been implicated in C. albicans virulence, at various stages of the infection process. Our results demonstrate that SAP expression depends on the type of infection, with different SAP isogenes being activated during systemic disease as compared with mucosal infection. In addition, the activation of individual SAP genes depends on the progress of the infection, some members of the gene family being induced immediately after contact with the host, whereas others are expressed only after dissemination into deep organs. In the latter case, the number of invading organisms determines whether induction of a virulence gene is necessary for successful infection. The in vivo expression technology allows the elucidation of gene expression patterns at different stages of the fungus-host interaction, thereby revealing regulatory adaptation mechanisms that make C. albicans the most successful fungal pathogen of humans and, at the same time, identifying the stage of an infection at which certain virulence genes may play a role.