Vaccine impedes the development of reflux-induced esophageal cancer in a surgical rat model: efficacy of the vaccine in a post-Barrett's esophagus setting

Preventive effect of oral hangeshashinto (TJ-14) on the development of reflux-induced esophageal cancer

BACKGROUND

Prostaglandin E2 is one of the potential products that promotes development of tumors and also is a strong inducer of M2 phenotype macrophages, which contribute to tumor development in the immunosuppressed microenvironment. Hangeshashinto (TJ-14), a Japanese traditional medicine (Kampo medicine), has been reported to be effective in preventing chemotherapy-induced oral mucositis through the reduction of prostaglandin E2. We previously developed a surgical rat reflux model of esophageal cancer and used this well-established animal model to investigate the action of TJ-14 in preventing esophageal cancer. We also assessed the effect of TJ-14 on the downregulation of prostaglandin E2 production, utilizing esophageal squamous cell carcinoma cell line exposed to bile acid.

METHODS

An end-to-side esophagojejunostomy was performed for the reflux model. A daily oral diet was subsequently administered, consisting of either diet-incorporated TJ-14 or standard diet as a control group. The rats were killed at 40 weeks after surgery. The incidence of esophageal cancer, Barrett's metaplasia, and proliferative hyperplasia were assessed histologically. CD163, a M2 phenotype macrophage marker, was assessed with immunohistochemistry. Prostaglandin E2 enzyme immunoassay and lactate dehydrogenase assay were performed on chenodeoxycholic acid or gastroesophageal reflux contents exposed to esophageal squamous cell carcinoma cell line.

RESULTS

Sixty-seven percent of the controls (n = 12) developed esophageal cancer, but animals that received TJ-14 (n = 10) had a cancer incidence of 10% (P=.007). Barrett's metaplasia was found in 83% of the rats in the control group and 50% of the rats in the TJ-14 indicating a protective tendency of TJ-14 (P=.095). All of the rats developed proliferative hyperplasia. The number of M2 phenotype macrophage were significantly decreased in the TJ-14 group compared to the control group in both Barrett's metaplasia and esophageal cancer lesions. TJ-14 inhibited chenodeoxycholic acid or gastroesophageal reflux content-induced prostaglandin E2 production in esophageal squamous cell carcinoma cell.

CONCLUSION

TJ-14 reduced the incidence of reflux-induced esophageal cancer and the infiltration of M2 macrophages in a surgical rat model or suppressed prostaglandin E2 production in esophageal squamous cell carcinoma cell. Further investigation is required regarding the potential clinical use of TJ-14 as an esophageal cancer chemopreventive agent.

Post-surgical gastrointestinal reflux disease: Status quo and treatment

Reflux is a common and tricky morbidity after gastrointestinal surgery which is caused by the destruction of physiological anti-reflux barriers, greatly affecting patients' postoperative quality of life. Gastroenterologists are now actively trying very hard to explore feasible, effective, and safe anti-reflux approaches. Conservative medical treatment, typically with proton pump inhibitors, is easily accepted by patients, however, its long-term adverse events are noteworthy. In the surgical aspect, laparoscopic anti-reflux surgery is gaining more and more popularity, after the first case of fundoplication. Besides, other operations, such as bariatric surgery, pediatric surgery, and pulmonary transplantation, are also frequently complicated by post-operative digestive reflux. Herein we systematically review the status quo and treatment modalities for post-surgical reflux disease, with the hope to facilitate surgeons to cope with this challenging issue appropriately.

Impact of inflammation-metaplasia-adenocarcinoma sequence and inflammatory microenvironment in esophageal carcinogenesis using surgical rat models

BACKGROUND AND AIMS

Chronic inflammation has been demonstrated to correlate with tumor onset and progression. Tumor-associated macrophages (TAMs) play an important role in inflammatory tumor microenvironment. We hypothesized that an inflammatory microenvironment around TAMs may promote the development of esophageal carcinomas when induced by duodenal content reflux without carcinogens.

ANIMALS AND METHODS

A total gastrectomy followed by esophagojejunostomy was performed on rats in order to induce chronic duodenal content reflux esophagitis. The animals were sacrificed sequentially, at the 20th, 30th, 40th and 50th week after surgery, and their esophagi were examined. The primary antibodies against CD68, CD163, pStat3 and Foxp3 were used. Expression and localization of infiltrated cells was assessed by immunohistochemical analysis.

RESULTS

At 20-weeks' post-surgery, squamous proliferative hyperplasia (PHP) and Barrett's metaplasia (BM) were observed. Adenocarcinoma (ADC) associated with BM, and squamous cell carcinoma (SCC) were observed 30-50 weeks' post-surgery. Numerous CD68 and pStat3-positive cells were identified surrounding PHP and BM after 20 weeks, and around ADC and SCC after 30 weeks. Moderate infiltration of CD163-positive macrophages was seen with BM, ADC, and SCC after 30 weeks. However, very few Foxp3-positive cells were observed around ADC and SCC.

CONCLUSION

Macrophages infiltrate the esophagus and activate the pStat3 pathway in stromal cells and epithelium. M2 phenotype macrophages infiltrate following infiltration of M1 macrophage and contribute to tumor development through regulatory T cells (Tregs). The involvement of immune cells such as TAMs and Tregs in the inflammatory microenvironment promotes esophageal carcinogenesis.

Rabeprazole impedes the development of reflux-induced esophageal cancer in a surgical rat model

BACKGROUND

The role of proton pump inhibitors in Barrett's metaplasia and esophageal adenocarcinoma has been an area of controversy.

AIMS

We evaluated the effectiveness of the proton pump inhibitor rabeprazole as a chemoprevention agent in a surgical rat reflux model of esophageal cancer.

METHODS

The rat reflux model was created by performing a jejuno-esophagostomy on Sprague-Dawley rats. The surgery promoted the reflux of gastro-duodenal contents into the esophagus. Rabeprazole sodium (Eisai, Tokyo, Japan) was dissolved in 0.9% physiological saline to a desired concentration of 1.5% (W/V). Beginning 4 weeks post-surgery, all animals were administered either 0.2 ml per 100 g body weight injections of rabeprazole or equivalent injections of saline 3 days per week into the subcutaneous tissue of the back. Forty animals were killed 40 weeks after surgery and their esophagi were examined. Of these, 23 were included in the control group, while the remaining 17 were subjected to rabeprazole.

RESULTS

While 74% (17/23) of the controls developed esophageal cancer, animals administered rabeprazole had an incidence of cancer of 29% (5/17) (p < 0.05, Fisher's exact test). Barrett's metaplasia was found on 100% (23/23) of the rats in the placebo group, but there was a protective effect in the rabeprazole group with 65% (11/17) of the rats displaying signs of Barrett's metaplasia (p < 0.05, Fisher's exact test). All of the rats developed proliferative hyperplasia.

CONCLUSIONS

Rabeprazole protected against the development of esophageal cancer in a clinically relevant surgical reflux model. Rabeprazole warrants further investigation for potential clinical use as a chemoprevention agent.

Barrett's esophagus: where do we stand?

Barrett's esophagus (BE) is a precursor for esophageal adenocarcinoma, which has an increased incidence rate over the last few decades. Its importance stems from the poor five-year survival of esophageal adenocarcinoma and current data that suggest a survival benefit when surveillance programs are implemented. In this review, we will cover the pathophysiology and natural history of BE and the different endoscopic findings. The prevalence of BE in different geographic areas and the incidence of high-grade dysplasia and adenocarcinoma in this patient population is reviewed. Recent recommendation for screening and surveillance of BE has been covered in this review as well as the efficacy of nonconventional imaging modalities and endoscopic ablation therapies.