Mitsuyuki Murano

Present status and strategy of NSAIDs-induced small bowel injury

Non-steroidal anti-inflammatory drugs (NSAIDs) are well known to cause gastroduodenal mucosal lesions as an adverse effect. Recently, the serious problem of NSAID-induced small intestinal damage has become a topic of great interest to gastroenterologists, since capsule endoscopy and balloon enteroscopy are available for the detection of small intestinal lesions. Such lesions have been of great concern in clinical settings, and their treatment and prevention must be devised as soon as possible. The prevalence of NSAIDs-induced small intestinal injury is higher than had been expected. Recent studies show that more than 50% of patients taking NSAIDs have some mucosal damage in the small intestine. The gross appearance of NSAID-induced enteropathy varies, appearing variously as diaphragm-like strictures, ulcers, erosions, and mucosal redness. To investigate NSAID-induced enteropathy, and to rule out other specific enteropathies, other useful methods (in addition to capsule endoscopy and balloon enteroscopy) include such modalities as radiological examination of the small intestine, the permeability test, scintigraphy or the fecal excretion test using 111Indium-labeled white blood cells, and measurement of the fecal calprotectin concentration. Diaphragm-like strictures and bleeding from mucosal breaks may be treatable with interventional enteroscopy. Misoprostol, metronidazole, and sulfasalazine are frequently used to treat NSAID-induced enteropathy, but have undesirable effects in some cases. In the experimental model, we confirmed that several existing drugs for gastroduodenal ulcers prevented indomethacin-induced small intestinal injury. Such drugs may be useful for preventing the adverse effects of NSAIDs not only in the stomach but also in the small intestine. We hope to examine these drugs in future clinical studies.

Therapeutic effect of intracolonically administered nuclear factor kappa B (p65) antisense oligonucleotide on mouse dextran sulphate sodium (DSS)-induced colitis.

Cytokines such as IL‐1, tumour necrosis factor‐alpha (TNF‐α), IL‐6 and IL‐8 are increased in inflamed colonic mucosa after administration of mouse DSS. Nuclear factor κB (NF‐κB) is a transcription factor which regulates the expression of these cytokine genes. The effect of intracolonically administered NF‐κB (p65) antisense phosphorothioate oligonucleotide was examined in mouse DSS‐induced colitis using drinking water containing 5% DSS. When antisense oligonucleotide was given on day 0, the disease activity index (DAI) representing clinical symptoms improved and the histological score decreased; furthermore, IL‐1, IL‐6, and TNF‐α concentrations in rectal mucosa were lower compared with the control group. Clinical and histological improvement was also observed when antisense oligonucleotide was begun on day 2 but not on day 7. In addition, the distribution of antisense oligonucleotides was investigated by confocal laser microscopy. In colonic mucosa, oligonucleotides were predominantly localized to cells in the lamina propria, but also in the epithelium. Western blot analysis using homogenized rectal mucosa showed the decreased expression of NF‐κB p65 in the antisense oligonucleotide‐treated group, although it was increased in the colitis group. These results suggest that intracolonic administration of NF‐κB antisense oligonucleotide may be effective in ulcerative colitis.

Comparative study of conventional colonoscopy and pan-colonic narrow-band imaging system in the detection of neoplastic colonic polyps: a randomized, controlled trial.

Background. Detection and removal of adenomas by colonoscopy is an important means for preventing cancer; however, small adenomas may be missed during colonoscopy. The narrow-band imaging (NBI) system clearly enhances the microvasculature in neoplastic lesions, making it appear as a dark complex. Therefore, the NBI system may improve the detection of colonic neoplasias. However, no randomized, controlled trials have evaluated the efficacy of a pan-colonic NBI system in adenoma detection. We conducted a randomized, controlled trial to determine the efficacy of the pancolonic NBI system in adenoma detection. Methods. Two hundred forty-three patients were randomized, 121 to conventional colonoscopy and 122 to pan-colonic NBI system. Demographics, indication for colonoscopy, and quality of preparation were similar between groups. Results. Extubation time was not significantly different between the conventional colonoscopy and pan-colonic NBI system. The proportions of patients with at least one adenoma and those with multiple adenomas were not significantly different between groups. However, the pan-colonic NBI system significantly increased the total number of adenomas detected (P < 0.05) and the number of diminutive (<5 mm) adenomas detected (P < 0.05). The pan-colonic NBI system allowed detection of more diminutive adenomas in the distal colon than did conventional colonoscopy (P < 0.01), and more patients in the NBI group had at least one diminutive adenoma than in the control group (P < 0.05). Conclusions. The pan-colonic NBI system improves the total number of adenomas detected, including significantly more diminutive adenomas, without prolongation of extubation time. These results indicate that routine use of the NBI system for surveillance of diminutive adenomas may be recommended.

Inhibition of dextran sulphate sodium (DSS)-induced colitis in mice by intracolonically administered antibodies against adhesion molecules (endothelial leucocyte adhesion molecule-1 (ELAM-1) or intercellular adhesion molecule-1 (ICAM-1)).

We examined the effect of intracolonic administration of anti‐adhesion molecule antibodies on DSS‐induced colitis in mice. Immunohistochemical staining in mice with colitis showed increased expression of ELAM‐1 and ICAM‐1 on endothelial cells of vessels in the lamina propria and submucosa at sites of inflamed lesions. Intracolonic administration of anti‐ELAM‐1 or anti‐ICAM‐1 antibody decreased bloody stools, anaemia, and histologically evident damage, as well as myeloperoxidase activity and IL‐1β content. We concluded that adhesion molecule expression is important in the development of DSS‐induced colitis in mice and that intracolonic administration of anti‐adhesion molecule antibodies, especially anti‐ELAM‐1 antibody, effectively inhibits the colonic inflammation. Intracolonic administration of anti‐adhesion molecule antibodies may show therapeutic promise in ulcerative colitis.

Expression of the EP4 Prostaglandin E2 Receptor Subtype with Rat Dextran Sodium Sulphate Colitis: Colitis Suppression by a Selective Agonist, ONO-AE1-329

Expression of the EP4 receptor, a prostaglandin (PG)E2 receptor subtype, as well as disease suppression by the administration of a selective EP4 agonist (ONO‐AE1‐329) was investigated in the colorectal mucosa of rats with dextran sodium sulphate (DSS)‐induced colitis. Rats were given drinking water containing 3% DSS for 2 weeks. Expression of EP4 receptor mRNA was barely detectable under normal conditions according to reverse transcription‐polymerase chain reaction (RT‐PCR). By 1 week after the initial administration of DSS, the receptor mRNA was strongly expressed. After ONO‐AE1‐329 was administered intracolonically to rats with DSS colitis for 7 consecutive days, erosion and ulceration decreased. Peripheral white blood cell (WBC) counts became less elevated. Interleukin (IL)‐1β and growth‐regulated gene product/cytokine‐induced neutrophil chemoattractant (GRO/CINC‐1) concentrations in colorectal mucosa were lower than in colitis control group (IL‐1β: 12.8 ± 4.6 and 30.8 ± 6.2 µg/mg protein, P < 0.05; GRO/CINC‐1: 15.5 ± 3.0 and 39.2 ± 5.4 µg/mg protein, P < 0.05), and the expression of the corresponding cytokine mRNA was strongly suppressed. IL‐10 concentration was higher than in control group (14.5 ± 1.7 and 7.9 ± 1.2 µg/mg, P < 0.05), and the mRNA was more strongly expressed. These results suggest that the EP4 receptor is important in colonic inflammation, and that PGE2 suppresses DSS colitis at least partly via the EP4 receptor and the above cytokine changes. Intracolonic administration of selective EP4 agonist might have therapeutic applicability in inflammatory bowel disease such as ulcerative colitis.

Estimation of Mucosal Inflammatory Mediators in Rat DSS-Induced Colitis

In order to investigate the mucosal injury mechanism in UC, we made dextran sulfate sodium (DSS)-induced colitis in rat and examined pathological findings, MPO activity, PGE2 level, and local mRNA expression and secretion of IL-1β, TNF-α, GRO/CINC-1 and IL-10 in DSS colitis mucosa. Moreover, we estimated the correlation between the severity of mucosal damage and changes of these local inflammatory mediators’ values. Neutrophil infiltration was marked and MPO activity was locally increased in proportion to the severity of mucosal damage. The mRNA expression and secretion of IL-1β, GRO/CINC-1 and IL-10 were increased. Especially, the secretions of IL-1β and GRO/CINC-1 were increased in proportion to the severity of mucosal damage. However, those of TNF-α were not increased in the colitis mucosa. An abnormal macrophage function and the presence of macrophage subtypes producing different cytokines would be predicted from our TNF-α data. The lesion was less severe in the colonic mucosa with higher levels of endogenous PGE2, while it was more severe in the colonic mucosa with lower levels of endogenous PGE2, implicating this compound as an inhibitory factor against the development of inflammation in the affected mucosa. Our results suggest that PGE2 might have therapeutic applicability to UC.

In vivo trial of a driving system for a self-propelling capsule endoscope using a magnetic field (with video).

BACKGROUND A capsule endoscope does not allow the examiner to observe a lesion from the desired direction in real time. OBJECTIVE To develop a driving system for a self-propelling capsule endoscope (SPCE) by using a magnetic field. SETTING Experimental endoscopic study in a live dog model. DESIGN AND INTERVENTIONS A microactuator was developed with the aim of remote-control operation. We developed a driving system for SPCE by attaching a capsule endoscope to this medical microactuator and performed the following experiments. (1) We operated this SPCE by remote control in the stomach of a dog under sedation and obtained endoscopic images using a real-time monitoring system only. (2) We placed a hemostatic clip on the gastric mucosa and recorded images of this clip with the SPCE. (3) We also placed clips at 2 other sites in the stomach and asked the SPCE operator, who was unaware of the location of the clips, to identify the site, number, and color of the clips. MAIN OUTCOME MEASUREMENTS Evaluation of performance of a driving system for SPCE. RESULTS The operator was able to obtain endoscopic images with the SPCE in the stomach of a dog in vivo, in any desired direction, by remote control. SPCE produced clear images of the clips placed in the stomach. The operator was able to easily identify the site, number, and color of the clips. LIMITATIONS Animal model. CONCLUSIONS Our trial suggests the possibility of clinical application of the driving system for an SPCE using a magnetic field.

A simple method of detecting K-ras point mutations in stool samples for colorectal cancer screening using one-step polymerase chain reaction/restriction fragment length polymorphism analysis

BACKGROUND We examined a technique for detecting point mutations of K-ras codon 12 in stool samples using one-step polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis, in order to determine whether it could be used to screen for colorectal cancer. METHODS DNA was extracted from 200-mg stool specimens of 5 healthy controls and 31 colorectal cancer patients. A 107-base-pair fragment of exon 1 of K-ras was amplified by PCR using mismatched primers. PCR products were digested with Bst NI and analyzed by gel electrophoresis followed by silver staining. Specificity of one-step PCR/RFLP was examined by using synthetic oligonucleotides. The detection limit of K-ras codon 12 mutations was determined by using SW480 and HT29 cells. RESULTS The K-ras gene was successfully amplified from all healthy controls and colorectal cancer patients studied. Mutations of K-ras codon 12 were not detected in any of the healthy controls, but were identified in 13 (41.9%) of the 31 patients with colorectal cancer. Mutations were detectable in all six synthetic mutant DNAs, while none were detected among the wild type. The detection limit of this method was > or = 0.1%. CONCLUSIONS PCR/RFLP analysis could be used in mass screening for colorectal cancer, because it is highly specific, has a low detection limit, and is simpler than conventional methods for detecting genetic abnormalities.

Prevention of NSAID-Induced Small Intestinal Mucosal Injury: Prophylactic Potential of Lansoprazole

Non-steroidal anti-inflammatory drugs (NSAIDs), which are used for the treatment of several inflammatory disorders including rheumatoid arthritis, are well known to cause gastroduodenal mucosal lesions as an adverse effect. Recently, the serious problem of NSAID-induced small intestinal damage has become a topic of great interest to gastroenterologists, since capsule endoscopy and double-balloon enteroscopy are available for the detection of small intestinal lesions. Such lesions have been of great concern in clinical settings, and their treatment and prevention must be devised as soon as possible. Proton pump inhibitors (PPI), such as lansoprazole and omeprazole, show a potent anti-secretory effect. PPIs also have a gastroprotective effect, independent of their anti-secretory actions, which is probably mediated by inhibition of neutrophil functions as well as antioxidant actions. Administration of lansoprazole reduced the severity of the intestinal lesions in a dose-dependent manner, but omeprazole had no effect. The amount of heme oxygenase-1 (HO-1) protein in the intestinal mucosa was significantly increased by lansoprazole, but not by omeprazole. These results suggest that lansoprazole, but not omeprazole, ameliorates indomethacin-induced small intestinal ulceration through upregulation of HO-1/carbon monoxide. Therefore, lansoprazole may be useful for preventing the adverse effects of NSAIDs not only in the stomach but also in the small intestine.

Role of Chymase-Dependent Matrix Metalloproteinase-9 Activation in Mice with Dextran Sodium Sulfate-Induced Colitis

Matrix metalloproteinase (MMP)-9 plays an important role in the pathogenesis of colitis. Recent studies have demonstrated that chymase is involved in the conversion of promatrix metalloproteinase (proMMP)-9 to MMP-9. However, whether chymase contributes to the activation of proMMP-9 in colitis has remained unclear. In this study, we administered 5% dextran sodium sulfate (DSS) solution to mice for 7 days. At 7 days after starting administration, both chymase activity and MMP-9 activity were significantly increased. In extract from colitis in DSS-treated mice, MMP-9 activity was significantly increased after 8 h of incubation, but increased activity was almost completely suppressed in the presence of a chymase inhibitor, 2-(5-formylamino-6-oxo-2-phenyl-1,6-dihydropyrimidine-1-yl)-N-[{3,4-dioxo-1-phenyl-7-(2-pyridyloxy)}-2-heptyl] acetamide (NK3201). At 7 days after starting administration, intestinal length was significantly shorter in DSS-treated mice than in normal mice, but these changes were significantly prevented by NK3201 (10 mg/kg per day i.p.). Disease activity index and histological damage score were also significantly reduced by NK3201. The filtrated neutrophil number was significantly decreased by NK3201. Furthermore, NK3201 significantly attenuated not only chymase activity but also MMP-9 activity in DSS-treated mice. These findings suggest that chymase plays an important role in the development of colitis via MMP-9 activation.