Department of Gastroenterology Division of Gastrointestinal Diseases

Departments of Clinical Sciences (Clinical Medicine)

Research Overview

1. Basic and clinical research into functional gastrointestinal disorders

Since functional dyspepsia is a syndrome with multiple causes, the pathology is complex, and possible causes include adaptive relaxation failure of the gastric fundus, delayed gastric emptying, hypersensitivity, sociopsychological factors, gastric acid, Helicobacter pylori infection, genetic factors, etc. We are conducting basic and clinical investigations into the relationship between each factor and the onset of symptoms.
We are attempting to grasp the pathology of adaptive relaxation failure of the gastric fundus and impaired gastric emptying by gastric scintigraphy and gastric barostat tests.
Because functional dyspepsia and irritable bowel syndrome can occur together, clinical trials are being conducted to determine the effects of drugs effective in treating each condition on the symptoms of each condition.
We are verifying the therapeutic effects of various drugs for functional dyspepsia and irritable bowel syndrome through clinical trials such as double-blind studies.
We perform specialized examinations such as esophageal pressure measurement tests for functional esophageal diseases such as achalasia, and also perform balloon dilation treatment.

2. Chemotherapy for gastrointestinal cancer

Malignant tumors account for a large proportion of upper gastrointestinal diseases, including esophageal and gastric cancer. While some patients benefit from minimally invasive treatments through early diagnosis, many patients are found to have advanced cancer that cannot be treated with surgery. Recently, not only cytotoxic anticancer drugs but also molecular targeted agents and immune checkpoint inhibitors have been used in second-line and later treatments, and it is expected that survival times will be extended. However, compared to colorectal cancer, this is still not sufficient, and clinical trials of new drugs or new administration methods are being conducted.
We are working on developing treatments aimed at further improving patients' quality of life by examining the safety and efficacy of various anticancer drugs. In particular, intraperitoneal chemotherapy, in which anticancer drugs are directly injected into the peritoneal cavity, is capable of strongly suppressing peritoneal dissemination, and is expected to lead to a cure for scirrhous gastric cancer. Our department is also participating in a physician-initiated clinical trial led by the University of Tokyo, "A randomized phase 3 comparison of systemic and intraperitoneal combined chemotherapy and systemic chemotherapy as postoperative or perioperative adjuvant chemotherapy for type 4 advanced gastric cancer (scirrhous gastric cancer)."

3. Clinical studies on gastroesophageal reflux disease and basic studies on the esophageal mucosal defense mechanism

Gastroesophageal reflux disease was previously said to be common in Europe and the United States, but in recent years, it has been increasing in Japan due to the Westernization of lifestyle habits, increased acid secretion, a decrease in the rate of Helicobacter pylori infection, an increase in obesity, etc. It has also been pointed out that the quality of life is declining significantly, and the development of more effective treatments is necessary, and the therapeutic effects of various drugs are being verified through clinical trials.
Esophageal sensory abnormalities have been noted in pathological conditions such as non-erosive gastroesophageal reflux disease, which does not show erosion, and we are attempting to clarify the pathological conditions using acid perfusion tests, esophageal barostat tests, and esophageal electrical stimulation tests. Furthermore, we are fundamentally investigating the expression analysis of pain-related proteins in the esophageal mucosa.
We have developed a normal human esophageal squamous epithelial cell layer model, and are attempting to determine the effects of acid and bile acid stimulation on the barrier function of the esophageal mucosal epithelium and to identify the cell layers and tight junction proteins that are important for the barrier function.

4. Endoscopic submucosal dissection for early cancer

In recent years, endoscopic submucosal dissection has become popular as a treatment for early cancer, and we are actively performing this treatment. Compared to previous mucosal resections, this treatment has problems with intraoperative and postoperative complications such as perforation and bleeding, and we are analyzing the causes of these complications and studying the necessary measures to prevent postoperative bleeding, such as post-resection hemostasis and drug administration methods. Furthermore, metachronous multiple cancer is also an important issue, and we are investigating the causes and control of this issue.
There is still much debate about the development of gastric cancer and gastric adenoma, and in recent years, many studies have been conducted based on differences in gastric mucus phenotypes, etc. We are focusing on the intercellular adhesion apparatus that may be related to proliferation and metastasis, and are investigating the relationship between its expression and adenoma/carcinoma.
The problem with endoscopic submucosal dissection for duodenal adenoma is that it has a high incidence of adverse events. It is important to perform the treatment safely and reliably. Therefore, we have begun a multi-institutional study on the efficacy and safety of cold polypectomy.

Treatment Overview

Our department diagnoses and treats gastrointestinal diseases, mainly functional gastrointestinal diseases and reflux esophagitis, endoscopic treatment of early cancer, and diagnosis and treatment of gastrointestinal cancer and intractable diseases. Our areas of expertise are as follows:

Diagnosis and treatment of gastroesophageal reflux disease (GERD)
Diagnosis and treatment of esophageal achalasia (24-hour pH monitoring, high resolution manometry)
Diagnosis and treatment of functional dyspepsia
Diagnosis and Treatment of Barrett's Esophagus
Diagnosis and treatment of Helicobacter pylori infection
Endoscopic treatment of early gastric cancer and early esophageal cancer (submucosal dissection)
Diagnosis and endoscopic treatment of early colorectal cancer (polypectomy, mucosal resection, submucosal dissection)
Endoscopic treatment for duodenal adenomas
Diagnosis and treatment of gastrointestinal submucosal tumors (EUS-FNA and incisional biopsy)
Diagnosis and treatment with double-balloon enteroscopy
Diagnosis using small and large intestine capsule endoscopy
Endoscopic procedures such as hemostasis and gastrostomy
Chemotherapy for advanced gastrointestinal cancer (esophagus, stomach, duodenum, small intestine, large intestine, GIST, etc.)
Diagnosis and treatment of inflammatory bowel disease
Treatment for drug-induced gastrointestinal mucosal injury
Diagnosis and Treatment of Irritable Bowel Syndrome
Diagnosis and Treatment of Constipation

Course Information

Professor: Shinichiro Shinzaki

Professor: Toshihiko Tomita

Clinical Professor: Hirokazu Fukui

Lecturer: Takuya Okugawa

TEL: 0798-45-6665

FAX: 0798-45-6661

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