Thromboxane A(2) receptor stimulation promotes closure of the rat ductus arteriosus through enhancing neointima formation.

Ductus arteriosus (DA) closure follows constriction and remodeling of the entire vessel wall. Patent ductus arteriosus occurs when the DA does not close after birth, and this condition is currently treated using cyclooxygenase inhibitors. However, the efficacy of cyclooxygenase inhibitors is often limited. Our previous study demonstrated that low-dose thromboxane A2 receptor (TP) stimulation constricted the DA with minimal adverse effects in rat neonates. However, its effect on DA remodeling remains unknown. In this study, we focused on the impact of the exogenous TP stimulation on the DA remodeling, especially intimal thickening. Using DA explants from rat fetuses at embryonic day 19 as a ex vivo model and primary cultured rat DA smooth muscle cells from embryonic day 21 as a in vitro model, we evaluated the effect of TP stimulation on the DA remodeling. The selective TP agonists U46619 and I-BOP promoted neointima formation in the ex vivo DA explants, and TP stimulation increased DA SMC migration in a dose-dependent manner. Both effects were inhibited by the selective TP antagonist SQ29548 or the siRNA against TP. TP stimulation also increased DA SMC proliferation in the presence of 10% fetal bovine serum. LC/MS/MS analysis revealed that TP stimulation increased secretion of several extracellular matrix proteins that may contribute to an increase in neointima formation. In conclusion, we uncovered that exogenous administration of TP agonist promotes neointima formation through the induction of migration and proliferation of DA SMC, which could contribute to DA closure and also to its vasoconstrictive action.

Feeding with olive oil attenuates inflammation in dextran sulfate sodium-induced colitis in rat.

Chronic inflammation of long-term ulcerative colitis contributes to an increased risk of colon cancer. Few studies address whether extra-virgin olive oil (EVOO) intake suppresses inflammation, cell proliferation and signal transducers and activators of transcription (STAT) in the experimental colitis model. The aim of this study was to assess whether a 5% EVOO suppressed inflammation, increased cell proliferation and the expressions of STAT3 and STAT3 phosphorylation (pSTAT3) in dextran sulfate sodium (DSS)-induced colitis. Rats were administered DSS via drinking water (weight percentage: 4%) for 1 week with a 1-week recovery period for three cycles. Rats were divided into three groups: control group, standard diet without DSS; DSS group, standard diet+DSS; and DSS+EVOO group, EVOO diet (weight percentage: 5%)+DSS. Rats were sacrificed 5 weeks after DSS was first administered, and colonic damage was histologically and biochemically evaluated. As a result, chronic feeding of 5% EVOO attenuated inflammation. This was evaluated using a disease activity index, body weight loss and a histological score. Enhanced expressions of STAT3, pSTAT3, COX-2 and iNOS by DSS was attenuated by EVOO. In addition, EVOO attenuated increases in cell proliferation (PCNA) caused by DSS and recovered decreases in apoptosis (cleaved caspase-3). In conclusion, the study indicated that chronic feeding of 5% EVOO inhibited chronic inflammation in DSS-induced colitis in rats and also attenuated cell proliferation and recovered apoptosis in DSS colitis.

Perforation and postoperative bleeding of endoscopic submucosal dissection in gastric tumors: analysis of 1190 lesions in low- and high-volume centers in Saga, Japan.

BACKGROUND: This retrospective study aimed to determine risk factors associated with serious complications of endoscopic submucosal dissection of gastric tumors in multicenters compared between high- and low-volume centers. METHODS: Between 2001 and 2010, gastric endoscopic submucosal dissection was performed in 1190 lesions of 1082 patients in five hospitals in Saga, three high-volume and two low-volume centers. Risk factors for serious complications were evaluated. Patients' background characteristics were evaluated, including anticoagulants use and underlying diseases. RESULTS: Postoperative bleeding was detected in 75 patients (6.9%), and perforation was detected in 40 patients (3.7%). Most postoperative bleeding and perforation cases were recovered with endoscopic procedures, although one case of each complication was treated by emergency surgery. Multivariate analysis indicated that risk factors for perforation were tumor location, massive submucusal invasion, endoscopists' experience of 100-149 cases and hypertension, and that risk factors for postoperative bleeding were tumor location, resected tumor size, and scar lesion. The serious complications were not different between high- and low-volume centers. CONCLUSIONS: The present study indicated that risk factors for perforation during endoscopic submucosal dissection were tumor, endoscopist and patient related, although risk factors for postoperative bleeding were tumor related. There was no difference in complications between high- and low-volume centers.

Expression patterns of the tumor suppressor PDCD4 and correlation with ß-catenin expression in gastric cancers.

The expression patterns of PDCD4, a tumor suppressor, and ß-catenin were immunohistologically investigated in gastric carcinoma tissues. In normal gastric tissues, PDCD4 was strongly expressed in the cell nuclei, but weakly expressed in the cytoplasm. In gastric adenocarcinoma tissues, nuclear PDCD4 expression was decreased, while cytoplasmic PDCD4 expression was unchanged or somewhat increased. In gastric signet ring cell carcinoma tissues, PDCD4 expression patterns were different from the expression patterns of the adenocarcinoma tissues, and PDCD4 was localized in the nuclei of the carcinoma cells as a belt in the middle of the epithelial layer. The nuclear localization of PDCD4 in the adenocarcinoma tissues was correlated with the membrane localization of ß-catenin, the activation of which stimulates invasion of colon cancer cells. PDCD4 expression was correlated with ß-catenin expression in gastric carcinoma cell lines, but not with E-cadherin, as the binding partner in the cell membrane.

Chemopreventive effect of mofezolac on beef tallow diet/azoxymethane-induced colon carcinogenesis in rats.

BACKGROUND/AIMS: We have previously shown that long-term consumption of 10% beef tallow diet promotes colon carcinogenesis in both saline- and azoxymethane (AOM)-treated rats. Here, we investigated the effects of mofezolac, a selective COX-1 inhibitor, on beef tallow-fed rats with saline- or AOM treatment. METHODOLOGY: Male SD rats were intraperitoneally injected with saline or AOM and fed 10% beef tallow diet with or without 1200 ppm mofezolac. At 12 weeks, aberrant crypt foci (ACF) were examined. At 44 weeks, tumors were counted, the proliferation and expression of COX-1 and 8-catenin on normal-appearing colonic mucosa was evaluated using the BrdU incorporation assay and Western blotting respectively. RESULTS: Mofezolac decreased the number of ACF at 12 weeks (p < 0.05) and reduced tumor multiplicity and incidence at 44 weeks in beef tallow-fed rats with AOM treatment (p < 0.05). At 44 weeks, reduction of the BrdU-positive cells (p < 0.05) and beneficial distribution changes of these cells within the colon crypts in both groups with mofezolac supplementation were observed. The expression of COX-1 and beta-catenin also reduced in mofezolac-added groups simultaneously (p < 0.05). CONCLUSIONS: This study suggested that mofezolac suppressed beef tallow-promoted colon carcinogenesis in rats, which probably was, appropriate for populations with high fat intake.

Conjugated linoleic acid suppresses colon carcinogenesis in azoxymethane-pretreated rats with long-term feeding of diet containing beef tallow.

BACKGROUND: We have indicated previously that long-term feeding of beef tallow increases colorectal cancer in rats. In this study, we investigated the effects of conjugated linoleic acid (CLA) on colon carcinogenesis in rats under long-term feeding of beef tallow diets, pretreated with azoxymethane (AOM). METHODS: Six-week-old male Sprague-Dawley rats were fed with 10% beef tallow diet only, 10% beef tallow with 1% CLA in triglyceride form (CLA-TG), or 10% beef tallow with 1% CLA in free fatty acid form (CLA-FFA). Colon carcinogenesis was induced by two intraperitoneal injections of AOM. Aberrant crypt foci (ACFs) were examined at 12 weeks. Cancer, cell proliferation, apoptosis, Wnt signaling, and the arachidonic acid cascade were examined at 44 weeks. RESULTS: At 12 weeks, CLA-TG and CLA-FFA attenuated the increase in ACFs induced by 10% beef tallow and AOM pretreatment. At 44 weeks, both forms of CLA attenuated multiple colon cancers, and CLA-FFA reduced the incidence of colon cancer to 50% of that seen with CLA-TG. CLA-TG and CLA-FFA decreased the number of 5-bromo-2'-deoxyuridine-positive cells in AOM-pretreated rats fed with 10% beef tallow. CLA-FFA increased the number of apoptotic cells and the activity of caspase-3 in the colon mucosa, and CLA-TG enhanced the activity of caspase-3. Both forms of CLA suppressed Wnt signaling and the arachidonic acid cascade in rats treated with beef tallow and AOM. CONCLUSION: These results suggested that CLA-TG and CLA-FFA suppressed colon carcinogenesis in rats with long-term feeding of a 10% beef tallow diet, through several mechanisms. The results of the present study with rats might be applicable to humans.

Evaluation of hemostasis with soft coagulation using endoscopic hemostatic forceps in comparison with metallic hemoclips for bleeding gastric ulcers: a prospective, randomized trial.

BACKGROUND: Endoscopic high-frequency soft coagulation, recently developed in Japan, is available for the management of gastric bleeding in cases of bleeding gastric ulcers and bleeding during endoscopic submucosal dissection. The aim of this study was to evaluate the efficacy of hemostasis with soft coagulation for bleeding gastric ulcers by comparing it with hemoclips in a prospective, randomized trial. METHODS: During the period of April 2006 to March 2008, 96 patients that had gastric ulcers with bleeding or nonbleeding visible vessels were enrolled in this study. All of the 96 patients were randomly divided into two groups: endoscopic hemostasis with soft coagulation (Group I) or endoscopic hemoclipping (Group II). RESULTS: A total of 41 (85%) out of 48 patients in Group I and 38 (79%) out of 48 patients in Group II were successfully treated with soft coagulation or clipping alone, respectively. The endoscopic hemostasis rate for the initial modality in combination with another endoscopic procedure performed after the initial method was 98% in both groups. One patient in Group I (2%) and five patients in Group II (10%) experienced recurrent bleeding. The time required to achieve hemostasis was shorter in Group I compared with Group II (9.2 +/- 11.1 vs. 13.6 +/- 9.4 min; P < 0.05). CONCLUSIONS: This study revealed that soft coagulation is as effective as hemoclipping for treating bleeding gastric ulcers. The time required to achieve hemostasis was shorter with the soft coagulation procedure.

Endoscopic hemostasis with metallic hemoclips for iatrogenic Mallory-Weiss tear caused by endoscopic examination.

AIM: Applied endoscopic techniques including mucosal resection, sclerotherapy and endoscopic retrograde cholangiopancreatography (ERCP) have been advanced and iatrogenic complications including Mallory-Weiss tear (MWT) occasionally occur in daily endoscopic procedures. The present study aimed to examine the advantages of clipping for MWT complications that occur during endoscopic examination. METHODS: Over 10 years, we experienced 47 patients with bleeding caused by MWT. Metallic hemoclips were applied for 38 patients for hemostasis. These patients were categorized into two groups: 18 patients in group A whose bleeding tear occurred during endoscopic examination in an iatrogenic condition, and 20 patients in group B visited the emergency unit due to other etiology of MWT. RESULTS: The background characteristics, including length of tears, were not different between the two groups. Initial hemostasis was 100% in groups A and B. Rebleeding was 0/18 (0%) in group A and 1/20 (5 %) in group B. Number of patients who received blood transfusion was significantly higher in group B (group A: 0/18, group B: 4/20). Hemoglobin level before hemostasis was 12.5 g/dL in group A which was not different to that in group B, 10.9 g/dL. CONCLUSION: Application of hemoclips was effective for bleeding MWT during endoscopic procedures, which warranted prophylactic application of hemoclips on MWT during endoscopic examination.

Long-term ingestion of reduced glutathione suppressed an accelerating effect of beef tallow diet on colon carcinogenesis in rats.

PURPOSE: We have shown previously that long-term feeding of beef tallow increases colorectal cancer in rats. This study investigated the effects of enzymic antioxidant, reduced glutathione (GSH), on colon carcinogenesis in rats fed with beef tallow. METHODS: Colon carcinogenesis was induced by intraperitoneal injection of azoxymethane (AOM) to rats. Rats were fed with 10% beef tallow supplemented with or without 1% GSH in drinking water. Aberrant crypt foci (ACF) and expression of beta-catenin in colonic mucosa were examined at 12 weeks. Cancers, related substances of oxidative stress and arachidonic acid cascade in plasma and normal colonic mucosa were determined at 44 weeks. RESULTS: GSH attenuated the number of ACF increased by beef tallow, but GSH had no influence on expression of beta-catenin increased by AOM. Incidence of colon cancer was no different with or without GSH, but GSH attenuated the number of colon cancers in each rat. GSH suppressed plasma malondialdehyde concentration. GSH increased GSH concentration and activities of catalase, glutathione peroxidase and superoxide dismutase in colonic mucosa, and decreased cyclooxygenase-2, prostaglandin E2 and thromboxane B2 levels. CONCLUSIONS: This study indicated that GSH suppressed the number of ACF, but the attenuation of colon carcinogenesis was limited to the number of colon cancers, although anti-oxidative effects and suppressive effects of arachidonic acid cascade were demonstrated by several indexes. These results suggested that colon carcinogenesis enhanced by beef tallow was partly caused by oxidative stress and arachidonic acid cascade, which were reduced by GSH.

Case series of endoscopic balloon dilation to treat a stricture caused by circumferential resection of the gastric antrum by endoscopic submucosal dissection.

BACKGROUND: Endoscopic submucosal dissection (ESD) plays an important role in the management of gastric neoplasms. There are few reports regarding stricture development caused by ESD of gastric neoplasms. OBJECTIVE: The present study aimed to determine the incidence of gastric stricture formation after ESD of gastric neoplasms and to report on the outcome and management of this complication: endoscopic intervention (ie, balloon dilation) versus surgery; the outcome of balloon dilation (success or failure/perforation). DESIGN: A case series from a retrospective review of gastric ESDs performed at Saga Medical School over a defined period of time. SETTING: Double-center territory, referral hospital. PATIENTS: An evaluation was performed in 532 patients with gastric mucosal tumors treated by ESD. A stricture was reported in 5 patients. All the 5 cases were located in the antrum. ESD that was performed in the cardia or the proximal stomach did not induce a stricture. RESULTS: Of the 5 cases of symptomatic gastric outlet obstruction, 1 patient required surgical intervention because of a near total gastric outlet obstruction not amenable to endoscopic intervention. The 4 patients underwent step-serial through-the-scope balloon dilations; in 2 patients, the procedure was successful, but in the other 2 patients, the procedure was complicated by a gastric perforation (50% incidence of perforation). LIMITATION: A retrospective study. CONCLUSIONS: Circumferential or subcircumferential resection by ESD in the antrum caused a stricture. Balloon dilation of the ESD gastric outlet obstruction might be a choice, but it is a risky treatment.

Indigestible material attenuated changes in apoptosis in the fasted rat jejunal mucosa.

We have previously demonstrated that fasting induced apoptosis and decreased cell proliferation in the rat intestinal mucosa. The aim was to investigate the effect of expanded polystyrene as indigestible material on apoptosis and cell proliferation in rat small intestinal mucosa during fasting. Male SD rats were divided into 3 groups. The first group was fed with chow and water ad libitum. The second group fasted for 72 hrs. The third group was fasted for 24 hrs and was fed expanded polystyrene. Intestinal apoptosis was evaluated by percent fragmented DNA assay, terminal deoxynucleotidyl transferase-mediated dUDP-biotin nick end-labeling (TUNEL) staining, and caspase-3 assay. Cell proliferation was analyzed by 5-bromo-2'-deoxyuridine (5-BrdU) uptake. Truncal vagotomy was performed to evaluate a role of the central nervous system. In the 72-hr fasted rat, mucosal height of the rat jejunum was decreased to 73% of that in rats fed ad libitum, and this decrease was partly restored to 90% in rats fed expanded polystyrene. The fragmented DNA was increased in fasted rats (28.0%) when compared with that in rats fed ad libitum (2.6%). The increase in fragmented DNA in fasted rats was recovered by feeding them expanded polystyrene (8.3%). TUNEL staining confirmed this result. The effect of polystyrene on apoptosis was decreased by truncal vagotomy. Expression of cleaved caspase-3 was increased in fasted rats, which was then decreased by feeding of expanded polystyrene. In contrast to apoptosis, feeding of expanded polystyrene had no reconstructive effect on 5-BrdU uptake in the intestinal epithelium, which was decreased by fasting to 60% of that in rats fed ad libitum. In conclusion, feeding of indigestible material partly restored the decrease in intestinal mucosal length in the fasted rats through the apoptotic pathway without any influence on BrdU uptake. Further exploration focused on the mechanism of this effect of indigestible material is required.

Suppression of intestinal mucosal apoptosis by ghrelin in fasting rats.

Ghrelin is mainly produced in the stomach and has several physiologic functions. The aim of this study was to investigate whether ghrelin regulates apoptosis in the small intestinal mucosa of fasting rats. Intestinal mucosal apoptosis was evaluated as the percentage of fragmented DNA, villus height, and terminal deoxynucleotidyl transferase-mediated dUDP-biotin nick end-labeling (TUNEL) staining and by Western blot analysis of caspase-3 in 48-hr fasting rats. Crypt cell proliferation was evaluated by counting the number of 5-bromo-2-deoxyuridine (BrdU) positive cells. Ghrelin was administered intraperitoneally at dosages of 2.5, 25, and 250 microg/kg per 48 hrs by continuous infusion via an Alzet micro-osmotic pump or injections at 12-hr intervals. Ghrelin was also infused in rats that underwent truncal vagotomy. The lowest dosage of ghrelin (2.5 microg/kg per 48 hrs) was administered into the third cerebroventricle. Ghrelin treatment attenuated the percentage of fragmented DNA in the small intestinal mucosa in 48-hr fasting rats in a dose-dependent manner. Continuous infusion of ghrelin and injections of ghrelin at 12-hr intervals suppressed intestinal apoptosis almost equally. This effect on apoptosis was not attenuated by truncal vagotomy. Cerebroventricular infusion of ghrelin also attenuated intestinal apoptosis. The antiapoptotic effect of ghrelin was confirmed by decreased TUNEL staining, recovery of the villus height, and decreased expression of caspase-3. BrdU uptake indicated that ghrelin enhanced cell proliferation in the intestinal crypt. Taken together, these data indicate that ghrelin enhanced intestinal growth with the suppression of small intestinal mucosal apoptosis in 48-hr fasting rats, suggesting that ghrelin controls intestinal function through the regulation of intestinal apoptosis.

Dysphagia in adult Japanese is not equivalent to the grade of endoscopic reflux esophagitis.

OBJECTIVE: This study was aimed to evaluate the correlation between dysphagia, detected by nursing staff in a brief interview and endoscopic findings in reflux esophagitis. PATIENTS AND METHODS: A total of 8,031 Japanese subjects without medication for gastrointestinal disease were briefly asked about the presence of heartburn, dysphagia, odynophagia, and acid regurgitation by nursing staff before endoscopy for assessment of esophagitis utilizing the Los Angeles Classification. RESULTS: The grade of endoscopic esophagitis was not equivalent to symptoms of dysphagia in 8,031 subjects. We evaluated the characteristics of subjects who complained of only dysphagia. Univariate analysis indicated that non-smoking, and non-drinking females were associated with a higher risk for dysphagia, and multivariate analysis indicated the gender was associated with dysphagia. There was no association of dysphagia with herniation and distribution of age. CONCLUSION: This study indicated that dysphagia was not equivalent to the endoscopic findings according to a brief interview by nursing staff and that dysphagia might be more common in females and those who do not smoke or drink.

Differentiation of gastric surface mucous cells (GSM06) induced by air-liquid interface is regulated partly through mitogen-activated protein kinase pathway.

BACKGROUND AND AIM: The aim of the present study was to examine the role of mitogen-activated protein (MAP) kinase pathway on gastric surface epithelium using an established cell culture model in which differentiation is promoted in GSM06 cells by air-liquid interface. METHODS: A double-dish culture system of mouse gastric surface mucous cell line GSM06 in Ham's F12 medium supplemented with 10% fetal calf serum and 50 microg/mL gentamicin at 37 degrees C in a humidified atmosphere of 5% CO(2) in air was used for an air-liquid interface. Culture cells were examined on histology, cell proliferation was evaluated by bromodeoxy-uridine (BrdU) uptake, and western blot analysis of extracellular signal-regulated kinase (ERK)1/2 and phosphate ERK1/2. On day 3, U0126, an inhibitor of MAP kinase kinase (MEK), was added to medium of incubated cells. RESULTS: GSM06 cells were differentiated with an air-liquid interface for 3 weeks. Compared to immersion control culture, phosphorylated ERK 1/2 expression increased significantly. This increase was completely suppressed with U0126, and tall columnar cells developed by air-liquid interface in GSM06 were not observed in U0126-treated cells. Increase in BrdU uptake with air-liquid interface was suppressed by U0126. CONCLUSION: These results suggested that MAP kinase signaling, activated by air-liquid interface, was, at least in part, related to cell differentiation in GSM06 cells induced by air-liquid interface.

Long-term feeding of various fat diets modulates azoxymethane-induced colon carcinogenesis through Wnt/beta-catenin signaling in rats.

The Wnt signaling pathway plays an essential role in carcinogenesis, and the amount of fat intake and composition of dietary fatty acids are crucial factors for colon carcinogenesis. We investigated whether various dietary fats affected the Wnt signaling pathway of colon tumorigenesis in azoxymethane (AOM)-treated rats. Male Sprague-Dawley rats were given intraperitoneal injections of AOM and supplemented with 10% corn, olive, beef, and fish oil for 44 wk. Aberrant crypt foci (ACF) and tumors were examined at 12 and 44 wk. Normal appearing colon mucosal proliferation and apoptosis were evaluated by 5-bromo-2'-deoxyuridine (BrdU) incorporation and percentages of fragmented DNA, respectively. Expressions of beta-catenin, cyclin D(1), Wnt2, Wnt3, and Wnt5a of normal appearing colon mucosa were analyzed by Western blot analysis. Long-term dietary corn oil and beef tallow increased ACF, tumor incidence, and tumor numbers in AOM-treated rats. In contrast, both olive and fish oil inhibited them. Dietary corn oil and beef tallow increased BrdU incorporation and the expression of cytosolic beta-catenin and cyclin D(1) and decreased apoptosis in the colon mucosa. Expressions of Wnt2 and Wnt3 in rats fed with beef tallow and Wnt5a in rats fed with corn oil increased with or without AOM-treatment. BrdU-incorporated cells were often observed at the tops of crypts in rats fed with beef tallow, whereas this was not observed in rats fed with the other diet. Long-term high intake of corn oil and beef tallow enhanced cell proliferation through Wnt signaling and modulated the distribution of proliferating cells, which might contribute to promoting effects in colon tumorigenesis.

Adipocytes and preadipocytes promote the proliferation of colon cancer cells in vitro.

Obesity, a risk factor for colon cancer, is associated with elevated serum levels of leptin, a protein produced by adipocytes. The aim of the present study was to clarify the effects of adipose tissue on colon cancer proliferation by using cultured cell lines. To achieve this, colon cancer cells (CACO-2, T84, and HT29) were cocultured with adipose tissue, isolated mature adipocytes, and isolated preadipocytes in a three-dimensional collagen gel culture system. The adipocytes and preadipocytes used were isolated from C57BL/6J and leptin-deficient ob/ob mice. Proliferation of the cancer cells was evaluated by nuclear bromodeoxyuridine uptake. The adipose tissue, mature adipocytes, and preadipocytes isolated from C57BL/6J mice significantly increased the proliferation of the colon cancer cells. This trophic effect of mature adipocytes on the cancer cell lines was observed only for cells from lean littermates and not for those from ob/ob mice. In contrast, the trophic effect of preadipocytes was not abolished in ob/ob mice, and this finding was supported by the result that leptin had a trophic effect on cancer cells. In conclusion, adipocytes were able to enhance the proliferation of colon cancer cells in vitro, partly via leptin, suggesting that adipose tissues, including mature adipocytes and preadipocytes, may promote the growth of colorectal cancer.