Anti-reflux anastomosis following esophagectomy for adenocarcinoma of the esophagogastric junction: impact of duodenogastroesophageal reflux and expression of cyclooxygenase-2 in the remnant esophagus

OBJECTIVE

Reflux is the principal complication for patients after esophagectomy with gastric reconstruction. The aim of this study was to investigate the effect of the modified Nissen fundoplication after resection of adenocarcinoma from the esophagogastric junction (AEG) on controlling the reflux and the role of duodenogastroesophageal reflux (DGER) and cyclooxygenase-2 (COX-2) expression level in the remnant esophagus.

PATIENTS AND METHODS

Sixty patients with AEG were randomly divided into two groups: (i) the conventional anastomosis group and (ii) the anti-reflux anastomosis group. Fifty esophagectomized patients were invited to participate in postoperative follow-up after 6 to 12 months. Among those we had 29 cases in the conventional anastomosis group and 21 in the anti-reflux anastomosis group. We used endoscopy, simultaneous 24 hours esophageal pH and bilirubin monitoring in this study. The COX-2 expression level in the remnant esophagus was detected using real-time PCR.

RESULTS

The reflux esophagitis prevalence in anti-reflux anastomosis group was comparable to that in the conventional group (p = 0.154). DeMeester score and fraction time of bilirubin abs >0.14 decreased more intensely in the anti-reflux anastomosis group (p < 0.05). The COX-2 expression level in of anti-reflux anastomosis group was evidently lower than that in the conventional anastomosis group (p = 0.022) while it was meaningfully higher compared to the normal control group (p = 0.046). COX-2 up-regulation as well as high prevalence of esophagitis were observed in simultaneous acid reflux and DGER (p < 0.05).

CONCLUSIONS

Although modified fundoplication following resection of AEG did not achieve an optimal effect on controlling reflux, it was very effective in decreasing the reflux. COX-2 expression monitoring can be considered as a possible new way to evaluate the impact of anti-reflux surgery. DGER occurring in acidic environment could develop severe reflux esophagitis and up-regulate the COX-2 expression.

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.

Duodenal reflux induces cyclooxygenase-2 in the esophageal mucosa of rats: evidence for involvement of bile acids

BACKGROUND & AIMS

Reflux of duodenal contents including bile acids is believed to contribute to esophageal injury and Barrett's esophagus. Cyclooxygenase (COX)-2, an inducible form of COX, has been implicated in both inflammation and carcinogenesis. In this study, we investigated the effects of bile acids and duodenal reflux on COX-2 expression in cultured esophageal cells and tissue, respectively.

METHODS

Immunoblotting and Northern blotting were used to assess the effects of bile acids on COX-2 expression in esophageal cell lines. Immunoblotting and immunohistochemistry were performed to evaluate the effects of duodenal reflux on COX-2 expression and cell proliferation in esophageal tissue.

RESULTS

Unconjugated bile acids were about fivefold more potent inducers of COX-2 messenger RNA, COX-2 protein, and prostaglandin synthesis than conjugated bile acids. Acidifying the culture medium sensitized esophageal cells to bile acid-mediated induction of COX-2. The induction of COX-2 by bile acids was mediated by phosphatidylinositol-3 kinase and extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases. In experimental animals, duodenoesophageal reflux led to esophagitis, marked thickening of the esophageal mucosa, and enhanced expression of COX-2. Increased immunoreactivity for Ki-67 and cyclin D1 indicated that enhanced cell proliferation contributed to mucosal thickening.

CONCLUSIONS

Reflux of duodenal contents into the esophagus led to increased COX-2 expression and mucosal thickening. Bile acids are likely to contribute to these effects.

Variability in the composition of physiologic duodenogastric reflux

Duodenogastric reflux has long been associated with various diseases of the foregut. Even though bile is often used as a marker, duodenogastric reflux consists of other components such as pancreatic juice and duodenal secretions. The aim of this study was to investigate the occurrence of duodenogastric reflux, its components, and the variability of its composition in normal subjects. Twenty healthy volunteers (7 men and 13 women) whose median age was 24 years underwent combined 24-hour bilirubin and gastric pH monitoring and intraluminal gastric aspiration. All probes were placed at 5 cm below the lower border of the lower esophageal sphincter. Aspiration was performed hourly and at any time when bilirubin and/or pH monitoring showed signs of duodenogastric reflux. Elastase and amylase were measured in the aspirate. All volunteers had episodes of physiologic duodenogastric reflux. A total of 70 episodes of duodenogastric reflux were registered with a median of three episodes (range 1 to 8) per subject. Most bile reflux occurred separately from pancreatic enzyme reflux. Pancreatic enzyme aspirate was significantly more often associated with a rise in pH in comparison to bile reflux (P <0.01). Duodenogastric reflux is a physiologic event with varying composition. Both bile and pancreatic enzyme reflux frequently occur separately. These findings could explain the disagreement regarding assessment and interpretation of duodenogastric reflux in the past. Thus monitoring of duodenogastric reflux requires more than the detection of just one component.

Bile acids as components of the duodenogastric refluxate: detection, relationship to bilirubin, mechanism of injury, and clinical relevance

Excessive reflux of bile into the stomach or esophagus has been associated with a variety of benign and malignant foregut disorders. The interaction of gastric acid with bile acids and the development of mucosal damage has been studied extensively in in vitro and in vivo animal models. These studies show that soluble bile acids can enter mucosal cells when in their non-ionized lipophilic form, accumulate there up to eight times the luminal concentration, and thus cause injuries to cell membranes and tight junctions. Entrance of mucosal cells and accumulation are pH-dependent and more pronounced at acidic pH ranges. The noxious effect of bile on intestinal mucosa is thus related not only to the concentration of luminal bile acids but also to the pH and the mucosal exposure time. Due to the lack of objective and accurate tests to quantitate reflux of bile acids in vivo over prolonged periods of time, the concept of bile reflux as a pathogenic factor in the clinical situation has been controversial. Recent studies indicate that intraluminal bilirubin can be used as a reliable marker of bile reflux into the stomach or esophagus. Combined 24-hour monitoring of intraluminal pH and bilirubin with the newly-developed Bilitec system, despite some system-inherent shortcomings, therefore has the potential to clarify the interactions between bile reflux, mucosal injury and gastroesophageal carcinogenesis.

[The ornithine decarboxylase activity of the gastric remnant mucosa: the effect of the duodenal juice with bile on the gastric mucosa]

Using male Wister rats, the ornithine decarboxylase (ODC) activity in the fundic mucosa has been determined from the duodenal juice with bile of a reflux model. The activity at 24 hours postoperatively presented a value approximately 18 times higher than the preoperative level. Though this level declined subsequently, it still was approximately two times higher four weeks later. The ODC activity in the corporal mucosa of humans was compared in 25 normal persons, in 21 patients with a gastric adenoma in 29 patients with a gastric cancer, in 20 patients who had undergone a Billroth I operation and in 20 patients who had undergone a Billroth II operation. No differences in ODC activity were observed among those with a gastric adenoma, a gastric cancer, and normal cases but significantly higher values were seen in cases with a remnant stomach, particularly those who had undergone Billroth II reconstructive surgery. Further, this activity tended to be especially high from 5 to 15 years postoperatively in cases with a gastric remnant.