Taiji Takahashi

Overexpression of a 60-kDa heat shock protein enhances cytoprotective function of small intestinal epithelial cells.

AIMS With the advancement of small intestinal (double balloon and capsule) endoscopy technology, incidence of small intestinal lesion caused by nonsteroidal anti-inflammatory drugs (NSAIDs) has been known to be high. However, therapy for small intestinal mucosal lesion has not yet been developed. Previous studies have shown that heat shock proteins (HSPs) are involved in cytoprotection mediated by their function as a molecular chaperone. In this study, we examined the effect of HSP60 or HSP70 overexpression on hydrogen peroxide-induced (H2O2) or indomethacin-induced cell damage in the small intestinal epithelial cells. MAIN METHODS cDNA of human HSP60 or HSP70 was transfected to rat small intestinal (IEC-6) cells, and HSP60- or HSP70-overexpressing cells were cloned. IEC-6 cells transfected with vector only were used as control cells. These cells were treated with H2O2 (0-0.14mM) or indomethacin (0-2.5mM). The cell viability was determined by MTT-assay. Cell necrosis was evaluated by LDH-release assay. Further, apoptosis was evaluated by caspases-3/7 activity and TUNEL assay. KEY FINDINGS Cell viability after H2O2 or indomethacin treatment was significantly higher in HSP60-overexpressing cells compared with that in control cells and HSP60-overexpressing cells. Apoptotic cells were also reduced in HSP60-overexpressing. CONCLUSION These results indicate that HSP60 plays an important role in protecting small intestinal mucosal cells from H2O2-induced or indomethacin-induced cell injury. HSP70-overexpressing cells did not show anti-apoptotic ability. SIGNIFICANCE These findings possibly suggest that function of each HSP is different in the small intestine. Therefore, for the therapy of small intestinal mucosal lesion, HSP60-induction therapy could be a new therapeutic strategy.

Large Brunner’s Gland Hyperplasia Treated with Modified Endoscopic Submucosal Dissection

Brunner’s glands are mucosal and submucosal alkalinesecreting glands that are most commonly located in the duodenum, especially in the first part of the duodenum, although they are rarely found in the pylorus and jejunum. Hyperplasia of these glands is normally seen in 2% of upper gastrointestinal (GI) endoscopies [1]. Five percent to 10% of benign duodenal tumors are caused by lesions of Brunner’s gland [2]. They are usually asymptomatic and lesions are discovered incidentally but they can occasionally cause symptoms such as GI hemorrhage and obstruction when they reach sizes >2 cm [3, 4]. In this paper, we report a case of large hyperplasia of Brunner’s gland successfully treated by modified endoscopic submucosal dissection (ESD) technique.

Successful Treatment of Refractory Duodenal Crohn’s Disease with Infliximab

Since the introduction of the anti-tumor necrosis factor (TNF) monoclonal antibody infliximab 1997, the treatment of Crohn’s disease has changed dramatically [1]. Duodenal Crohn’s disease is rare and unique in that its clinical response to medical therapy is universally poor and usually requires surgical therapy such as gastrojejunal bypass [2]. We present one case of duodenal Crohn’s disease with severe stricture that was resolved by treatment with infliximab. In March 2004, a 17-year-old man presented with abdominal pain and diarrhea; he was diagnosed as having Crohn’s disease in the colon. He was treated with corticosteroid (predonisolone, 40 mg/day) and mesalazine (Pentasa, 3.0 g/day). His symptoms and colonic lesions resolved and he was discharged in June 2004. He was maintained on mesalazine (Pentasa, 3.0 g/day) and corticosteroid (predonisolone, 10 mg/day) to prevent recurrence. Also, he was on enteral nutrition therapy using an elemental diet. In August 2004, he suddenly developed severe upper abdominal pain, abdominal distension, nausea, and vomiting. Abdominal CT scan showed marked wall thickness of duodenum. An upper GI X-ray showed a stricture of duodenum (Fig. 1). Endoscopic examination revealed a stricture with a large ulceration and mucosal edema in the duodenum bulb. Histologically, the biopsy specimen of the duodenal mucosa revealed marked active chronic inflammation with

Target molecules of molecular chaperone (HSP70 family) in injured gastric mucosa in vivo

AIMS Several recent studies, including ours, have indicated the importance of heat shock proteins (HSPs) in cytoprotection against cytotoxic agents and environmental stresses mediated by the chaperone function of HSPs (molecular chaperones). However, the target molecule that is recognized by HSPs in damaged cells currently remains unknown. As HSPs rapidly recognize and bind to degenerated protein in cells, target molecules of HSPs might be key molecules for the initiation and pathogenesis of cellular damage. In the present study, gastric mucosal proteins that specifically bind to the HSP70 family (HSC70) were analyzed using HSC70-affinity chromatography. MAIN METHODS The gastric mucosa was removed from Sprague-Dawley rats after exposure to water immersion-stress for 0, 1, 3 or 5 h. Soluble fractions of each gastric mucosa were applied to the HSC70-affinity column separately. After washing off non-specific binding proteins, specific binding proteins were eluted by ATP-containing buffer. Binding proteins were analyzed by SDS-polyacrylamide gel electrophoresis. In addition, the amino acid sequence of purified proteins was also analyzed. KEY FINDINGS Specific HSC70-binding proteins with a molecular weight of 200-kDa and 45-kDa were eluted from an affinity column when gastric mucosal homogenate of 1-h stress exposure was applied. The amino acid sequencing showed that these binding proteins were cytoskeletal myosin (heavy chain) and actin, respectively. SIGNIFICANCE During the pathogenesis of stress-induced gastric mucosal damage, structurally degenerated cytoskeletal myosin (heavy chain) and actin may be key or initiation molecules which structural changes were firstly recognized by molecular chaperone.

Mallory-Weiss tear during gastric endoscopic submucosal dissection

A 78-year-old woman was referred to our department for treatment of an early gastric cancer. Esophagogastroduodenoscopy (EGD) demonstrated a flat elevated lesion and a polypoid lesion on the greater curvature of the antrum. Histological analysis of, endoscopic biopsy samples taken from these lesions revealed an adenocarcinoma and a hyperplastic polyp, respectively. ESD was conducted for removal of the lesions. Carbon dioxide (CO(2)) instead of room air was used for insufflation, and the patient was adequately sedated without struggling or vomiting during the treatment. No significant bleeding from the lesion was observed during ESD, but fresh blood was identified endoscopically. Surprisingly, a Mallory-Weiss tear with active bleeding was detected on the lesser curvature of the gastric corpus. A total of eight hemoclips were applied for hemostasis. Both lesions were completely removed en bloc, and no bleeding or perforation developed after ESD. Histologically, the first lesion was a papillary carcinoma limited to the mucosal layer and without lymphovascular invasion or involvement of the surgical margins, while the second lesion was a benign hyperplastic polyp.

Specific induction of a 72-kDa heat shock protein protects esophageal mucosa from reflux esophagitis

AIMS The aim of this study is to investigate the expression and cytoprotective function of a 72-kDa heat shock protein (HSP72) using a reflux esophagitis model in rats. MAIN METHODS Expression of HSP60, HSP72, and HSP90 in rat esophageal mucosa was evaluated by Western blot analysis before and after hyperthermia (42.5 degrees C, 20 min). Rats received the operation to produce reflux esophagitis with or without pretreatment with hyperthermia to induce HSPs. The esophageal mucosal damage was evaluated 12 h after the operation. KEY FINDINGS Expression of HSP72 was significantly increased by hyperthermia in rat esophageal mucosa. Reflux esophagitis was dramatically prevented when HSP72 was preinduced by hyperthermia. Furthermore, activation of TNF-alpha and IL-1beta in esophageal mucosa was also suppressed. SIGNIFICANCE These results suggested that hyperthermia protects the esophageal mucosa in reflux esophagitis model by inducing HSP72 and suppressing proinflammatory cytokine activation. These findings might suggest that HSP-inducing therapy could be a novel and unique therapy for reflux esophagitis.

Correlation of Heat Shock Protein Expression to Gender Difference in Development of Stress-Induced Gastric Mucosal Injury in Rats

Recent studies have indicated that heat shock proteins (HSPs), which function as molecular chaperones, play important roles in cellular responses to stress-related events. However, the gender difference in the expression of HSP in the gastric mucosa remains unclear. In order to understand the mechanism of gender difference in the prevalence or severity of gastric mucosal lesions, the expression level of HSP and the correlation of estrogen to HSP induction in the gastric mucosa were evaluated in this study. The basal expression levels of HSP60 and HSP90 in the gastric mucosa were significantly higher in females than those in males. The gastric ulcer index was significantly higher in male rats compared to female rats observed after 12 h water immersion stress exposure. At this time point, the expression levels of HSP60 and HSP90 in the gastric mucosa were significantly higher in females than those in males. An estrogen-treatment significantly induced the expression of HSP60, HSP70 and HSP90 in the gastric mucosa. Inversely, an ovariectomy dramatically reduced the expression of HSP60, HSP70 and HSP90 in the gastric mucosa. Our results suggested that estrogen might play an important role in gastric mucosal protection with the induction of gastric mucosal HSPs.

Rapid Regression of Multiple Gastric Carcinoid Tumors with Hypergastrinemia and Atrophic Gastritis after Renal Transplantation

To the Editor Gastric carcinoid tumors are rare. Nevertheless, when they occur, they are often found in patients diagnosed as having type A gastritis [1]. In patients with type A gastritis, the development of carcinoids and the widespread hyperplasia of enterochromaffin-like cells are related to atrophic changes of fundic mucosa and the trophic action of subsequently raised serum gastrin levels. In the past gastrectomy was the treatment of choice for carcinoid tumors; however, recent reports have shown that multiple gastric carcinoid tumors associated with type A gastritis are indolent and recommend that patients should receive more conservative treatment [1, 2]. We herein present one case where multiple gastric carcinoid tumors with hypergastrinemia and type A gastritis regressed after renal transplantation. In November 2000, a 51-year-old woman presented with epigastric pain and she received upper gastrointestinal endoscopy in our hospital. Endoscopic examination revealed multiple gastric polyps in the body and funds (Fig. 1). The polyps, measuring between 1 and 15 mm, were covered by intact mucosa identical to the surrounding tissue. The intervening gastric mucosa appeared atrophic with a pale shiny lining and visible submucosal vessels. Biopsies were taken for a histopathology of the polyps. Biopsies of the polyps showed gastric carcinoid tumors (Fig. 2), cells were positive for chromogranin A, synaptophysin, and neuron-specific enolase. Serum gastrin level was over 3,000 pg/ml (normal 0–90). Serum serotonin and urine 5-HIAA levels were normal. Antiparietal cell antibody was negative. Helicobacter pylori serology was negative. The patient was diagnosed as having multiple type I gastric carcinoid tumors. The question was how to manage this case. The patient did not want to receive surgical treatment, such as a total gastrectomy or antrectomy, because she had already received hemodialysis treatment for chronic renal failure. Therefore,with agreement of the patient, we decided to do an endoscopic follow-up. We performed endoscopic examination at six-month intervals. Between 2000 and 2004, follow-up endoscopy showed that the polyps had the same size as on the initial picture, and a histological examination of biopsies specimens revealed a residual carcinoid tumor in the mucosal layer. In December 2004, she received renal transplantation. After renal transplantation, she was treated with corticosteroid ( prednisolone, 10 mg/day) and Tacrolimus (Prograf, 4 mg/day) to prevent kidney graft rejection. The endoscopic examination at three months after renal transplantation showed marked regression of the carcinoid tumors. Furthermore, the endoscopic examination at six months after renal transplantation showed complete regression of the disease, though the serum gastrin level was still high (over 3,000 pg/ml) (Fig. 3). The endoscopic examination showed no progression of tumors at the end of the follow-up. Gastric carcinoid tumors fall under the broad classification of foregut carcinoid tumors. However, it is well known that these tumors are clinically and biologically distinct from the carcinoid tumors involving the rest of the gastrointestinal tract. In 1993, Rindi et al. classified gastric carcinoid tumor into three subtypes, based on pathogenesis [3]: type I and type II gastric carcinoids develop under the trophic influence of gastrin, whereas type III carcinoids are M. Odashima (&) M. Otaka M. Jin Y. Horikawa T. Matsuhashi R. Ohba N. Mimori S. Koizumi N. Kinoshita T. Takahashi S. Watanabe Department of Gastroenterogy, Akita University School of Medicine, 1-1-1, Hondo, Akita city, Akita 010-8543, Japan e-mail: odashima@doc.med.akita-u.ac.jp