Increased immunoreactivity of cathepsins in the rat esophagus under chronic acid reflux esophagitis.

We have designed a stable rat chronic acid reflux esophagitis (RE) model. In gastrointestinal lesions, several lysosomal cathepsins are known to participate in epithelial permeability in cell-cell connections, such as tight junctions in ulcerative colitis. However, very few studies have focused on the distribution of cathepsins in the esophageal multilayer squamous epithelium. Therefore to clarify the role of cathepsins in RE, we investigated their immunohistological localization in the esophageal epithelium under normal conditions and after RE. Of the cathepsins examined (cathepsins B, C, D, F, H, L, S, and X), granular immunoreactivity for cathepsins B, C, D and L was observed in the control esophageal epithelia; although, their distribution differed depending on the enzyme examined. In the RE model, immunoreactivity of these cathepsins was increased in esophageal epithelial cells and activated macrophages. The immunoreactivity for cathepsins F, H, S and X was barely detectable in the control esophageal epithelium. However, in the RE model, we noticed a slight increase in the expression of cathepsins H and X in the epithelial cells. Furthermore, activated macrophages of the RE model possessed intense immunoreactivity for these cathepsins, which may have been related to esophageal inflammatory mechanisms.

Analysis of brain activity during visceral stimulation.

BACKGROUND AND AIM: Functional magnetic resonance imaging (fMRI) is a useful technology for investigating regional metabolic activity in the brain. Many experiments using fMRI have been performed, but because of variations in protocols and analytic techniques, the results vary. When a priori information of the task is known, a model-based technique, such as statistical parametric mapping, is often used for analysis. In the case of acid stimulation of the esophagus the task model is unclear, so we analyzed brain activity during an acid or isotonic saline infusion to the esophagus using independent component analysis (ICA), which does not depend on a priori information of the task. METHODS: Six healthy male volunteers (29-45 years) participated in the study. A multi-lumen catheter was inserted transnasally and side-hole infusions ports were approximately 15 cm proximal to the lower esophageal sphincter. The experimental protocol was 5-min interval, 5-min saline infusion, 5-min interval, 5-min 0.1 N HCl, and a final 5-min interval. After magnetic resonance scanning, fMRI image data were analyzed using group ICA. RESULTS: The cerebral regions activated during the first interval, saline infusion, and HCl infusion were the thalamus, insula, cingulate gyri, temporal pole and some parts of the frontal, parietal, temporal and occipital lobes. Activation of the postcentral and precentral gyri occurred during both infusions, but was not observed during the first interval. CONCLUSION: ICA, which can show the cerebral areas activated in relation to liquid in the esophagus, may be a powerful technique for studying the brain's response to visceral stimulation.

Clinical feature of asymptomatic reflux esophagitis in patients who underwent upper gastrointestinal endoscopy.

BACKGROUND AND AIM: Prevalence of gastroesophageal reflux disease (GERD) varies in regions, but few reports on clinical features and quality of life (QOL) of asymptomatic GERD exist in Japan. METHODS: Endoscopy was performed in our department between April 2008 and September 2010. Among 6409 cases answering Frequency of Scale for the Symptoms of GERD (FSSG) and SF8 QOL (PCS: physical component summary; MCS: mental component summary), proton pump inhibitor or histamine 2 receptor antagonist users were excluded, and 388 cases diagnosed as reflux esophagitis (RE) (Los Angeles Classification grade A, B, C, D) were analyzed. Asymptomatic cases with FSSG total score = 0 were defined as asymptomatic RE (AsymRE) and FSSG total score ≥ 1 as symptomatic RE (SymRE). Each clinical feature was analyzed. RESULTS: The frequency of AsymRE was 11.6% of RE (AsymRE, n = 45; SymRE, n = 343). Patient characteristics in AsymRE, SymRE were male/female = 35/10; 239/104 (not significant), mean age (year) = 63.5 ± 14.3; 58.3 ± 12.7 (P < 0.01), body mass index = 23.9 ± 4.3; 23.5 ± 3.7 (ns), respectively. Regarding the grade of RE, grade A 80.0%, B 17.8%, C 2.2% and D 0% in AsymRE, and grade A 72.6%, B 24.8%, C 2.0% and D 0.6% in SymRE (ns). PCS in SF8 was AsymRE; SymRE = 51.8 ± 9.8; 49.0 ± 7.7 (P < 0.01) and MCS in SF8 was AsymRE; SymRE = 51.4 ± 9.4; 48.2 ± 7.6 (P < 0.01), respectively. CONCLUSION: The prevalence of asymptomatic RE was high, particularly in elderly subjects. Unlike symptomatic RE, QOL was not impaired at all with asymptomatic RE. No differences were seen between groups in clinical features such as endoscopic severity of RE, indicating that asymptomatic RE is a condition that should not be overlooked clinically.

Dissociation and dispersion of claudin-3 from the tight junction could be one of the most sensitive indicators of reflux esophagitis in a rat model of the disease.

BACKGROUND: The aim of this study was to characterize pathological lesions of the esophageal epithelial tight junction (TJ) complex in a rat reflux esophagitis (RE) model in a search for a reliable diagnostic indicator. METHODS: Rats underwent an operation to induce RE, with or without rabeprazole treatment (1.0 and 10.0 mg/kg/day). Sham-operated rats served as a control. Fourteen days after the operation, esophagi were isolated from the rats and submitted to double-label confocal immunofluorescence microscopy, and biochemical analyses. RESULTS: Immunofluorescence microscopy revealed that claudins-1, -3, and -4 were located on the surfaces of epithelial cells in the normal esophagus of the control group, although there were differences in the distribution patterns between claudin-3 and claudins-1 and -4 in the epithelial layer. However, in RE, the immunoreactivity of claudin-3 on the cell surface was decreased, and it appeared instead as a faint granular pattern within the epithelial cytoplasm. Claudin-3 expression in the entire esophageal epithelium was also decreased. The expression and location of claudins-1 and -4 in epithelial cells were basically unaffected in RE. Gastric acid-induced dissociation of claudin-3 elicited instability of the epithelial TJ complex, which was confirmed by sedimentation analysis using centrifugation in a sucrose density gradient. Rabeprazole (10.0 mg/kg/day) attenuated these alterations. CONCLUSIONS: Our data indicate that the dispersion of claudin-3 from esophageal epithelial plasma membranes to cytoplasm and the resulting instability of the TJ complex could be one of the most specific and sensitive indicators for monitoring inflammatory and recovery processes in RE.

Establishment of a reflux esophago-laryngitis model in rats.

BACKGROUND: To investigate the pathophysiology of reflux laryngitis, an experimental model is required. AIM: The aim of this study is to establish an animal model of reflux esophago-laryngitis, modifying our previously reported model of chronic acid reflux esophagitis. METHODS: The modified chronic acid reflux esophagitis (m-RE) group (n = 10), in which the duodenum was wrapped with 2.5 mm of Nelaton catheter, was not treated with any drugs. Also postoperatively, two treatment groups (n = 10 in each) received different dosages of rabeprazole (RPZ): 1.0 mg/kg/day (RPZ 1.0 group) or 10.0 mg/kg/day (RPZ 10.0 group). As a control group (n = 5), other rats underwent sham operation. The esophagus and larynx were resected on day 14 after the operation, and ulcer score of the esophagus was assessed. The epithelial thickness and leukocyte infiltration of the supraglottic and subglottic laryngeal mucosae were investigated. The number of interleukin (IL)-1ß-positive cells was also counted and defined as the IL-1ß labeling index. RESULTS: In the m-RE group, the epithelial thickness, leukocyte infiltration, and IL-1ß labeling index of the supraglottic and subglottic laryngeal mucosae were increased compared with controls (P < 0.01). In the RPZ groups, not only the ulcer score of esophagus but also the epithelial thickness, leukocyte infiltration, and IL-1ß labeling index of both the supraglottic and subglottic laryngeal mucosae were decreased dose-dependently relative to the m-RE group (P < 0.05). CONCLUSIONS: Our modified chronic acid reflux esophagitis model proved useful in establishing a rat reflux esophago-laryngitis model, with both pathological laryngeal findings and reflux esophagitis shown to be improved by administration of a proton pump inhibitor.

Observational comparative trial of the efficacy of proton pump inhibitors versus histamine-2 receptor antagonists for uninvestigated dyspepsia.

BACKGROUND AND AIMS: It is still controversial which drugs, proton pump inhibitors (PPI) or histamine-2 receptor antagonists (H2RA), are more effective for dyspepsia in the Japanese population. METHODS: Patients with uninvestigated dyspepsia (n = 104; male/female 41/63) were treated with either rabeprazole 10 mg o.d. (n = 62) or lafutidine 10 mg b.i.d. (n = 42) for 4 weeks. Questionnaires (modified Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease [mFSSG] and quality of life [QOL], SF-8) were administered before and after therapy. The mFSSG was classified into a total score (Q-T), reflux score (Q-R), dyspepsia score (Q-D) and pain score (Q-P). The SF-8 had a physical component summary (PCS) and mental component summary (MCS). The predominant type of symptom was reflux (R-S), pain (P-S) or dysmotility (D-S). RESULTS: R-S was 19.2%, P-S 48.1%, D-S 24.0% and overlap 8.7%. In the R-S, Q-T and Q-R significantly improved with rabeprazole, but neither scale improved with lafutidine. MCS significantly improved with rabeprazole. In P-S, Q-T, Q-R, Q-D and Q-P significantly improved with both drugs. PCS significantly improved with both, whereas the MCS significant improved with rabeprazole. In D-S, Q-R and Q-D significant improved with rabeprazole, but neither improved with lafutidine. QOL did not improve with either. With overlap, neither scale nor the QOL reached a significant difference. CONCLUSION: Both PPI and H2RA have a positive effect on P-S, but H(2)RA therapy is limited for R-S and D-S, whereas PPI therapy is generally effective. Therefore, careful prescription based on symptoms is important.

Characteristic pathological findings and effects of ecabet sodium in rat reflux esophagitis.

AIM: To explore the pathological findings in the entire esophagus in rats with reflux esophagitis, and the effects of ecabet sodium (ES). METHODS: A rat model of chronic acid reflux esophagitis was used. In the treatment group, ES was administered after surgery (n = 16). No drug was administered postoperatively to the esophagitis group (n = 9). Sham-operated rats were used as a control group (n = 5). Rats were sacrificed on day 7 after the operation. The epithelial thickness and leukocyte infiltration were examined in the upper, middle and lower areas of the esophagus. The survival rate, incidence of esophageal ulcer, and mean surface area and number of esophageal ulcers were determined in the esophagitis and ES groups. Esophageal histology was assessed in all three groups. RESULTS: Leukocyte infiltration in the esophagitis group was 26.3 +/- 22.0 in the middle esophagus and 8.2 +/- 4.9 in the upper esophagus, which was significantly greater than that in the controls (1.3 +/- 1.1 and 1.4 +/- 1.0, respectively) (P < 0.05). The thickness of the epithelium in the esophagitis group was 210.8 +/- 47.7 microm in the lower esophagus and 204.2 +/- 60.1 microm in the middle esophagus, which was significantly greater than that in the controls (26.0 +/- 5.5 and 21.0 +/- 6.5 microm, respectively) (P < 0.05). The mean number of ulcers per animal in the ES group in the entire esophagus was 5.4 +/- 2.5, which was significantly less than that in the esophagitis group (9.0 +/- 3.5) (P < 0.05). The epithelial thickness in the ES group was 97.5 +/- 32.2 microm in the lower esophagus, which was decreased compared with that in the esophagitis group (210.8 +/- 47.7 microm) (P < 0.05). CONCLUSION: Mucosal inflammation extended to the upper esophagus close to the hypopharynx. Our study suggested that ES may have a useful defensive role in reflux esophagitis.