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.

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.

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.

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.

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.

Hamartomatous inverted polyp successfully treated by endoscopic submucosal dissection.

We report a case of gastric hamartomatous inverted polyps that are a rare histological type of gastric polyp and difficult to diagnose. Gastric submucosal tumor was detected by upper gastrointestinal X-ray series in 37-year-old man. Endoscopy revealed a submucosal tumor (SMT) , which eroded with a depression on its surface in the fornix. Endoscopic ultrasonography showed a heterogeneous tumor in the third layer. Endoscopic submucosal dissection (ESD) was performed to resect the tumor completely. The pathological diagnosis was a gastric hamartomatous inverted polyp. The patient was later discharged without any complications. Hamartomatous inverted polyps without a stalk are classified as the SMT type because the tumor is inverted down growth into the submucosal layer, otherwise polyps with a stalk are classified as the polyp type. All of the polyps were resected endoscopically, however, surgical resection was performed for those of the SMT type, because it is difficult to remove this type completely by en-block resection using conventional EMR technique. ESD method may be indicated for SMT-type hamartomatous inverted polyps.