Ken Toshina

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.

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.

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.

Enprostil, a Prostaglandin‐E2 Analogue, Inhibits Interleukin‐8 Production of Human Colonic Epithelial Cell Lines

We previously reported that intracolonic administration of enprostil, a prostaglandin‐E2 (PGE2) analogue, had therapeutic effects on acute colitis induced in rodents by dextran sulfate sodium (DSS). In addition, production of growth‐regulated gene product/cytokine‐induced neutrophil chemoattractant‐1 [GRO/CINC‐1; an interleukin(IL)‐8 like cytokine] was suppressed in the inflamed tissues. In the present study we used a human colon cancer cell line (HT‐29) to investigate enprostil effects on the IL‐8 production of intestinal epithelial cells stimulated by various stimulants. In a MTT assay, concentrations of enprostil >10−5M had cytotoxitic effects on HT‐29 cells. Furthermore, 10−6 M enprostil suppressed IL‐8 production in HT‐29 cells, SW620 and CaCo2 stimulated with interleukin‐1β (IL‐1β) or lipopolysaccharide (LPS), but did not suppress this response when cells were stimulated with tumour necrosis factor (TNF)‐α. These results suggest that enprostil affects a point in the pathway between the IL‐1 receptor or LPS receptor and nuclear factor‐κB(NF‐κB), without affecting the pathway between the TNF receptor and NF‐κB, with the latter factor being required for the IL‐8 gene transcription. The therapeutic effect of exogenous enprostil on DSS colitis may involve the inhibition of IL‐8 production in colonic epithelial cells stimulated by IL‐1β or LPS.

Usefulness of polyethylene glycol solution with dimethylpolysiloxanes for bowel preparation before capsule endoscopy.

Background and Aim:  Capsule endoscopy (CE) is widely used for diagnosing small intestinal diseases. In some cases, however, observation of target sites is very poor during CE because of residues etc. Herein we report the usefulness of a preparation comprised of polyethylene glycol solution (PEG) for CE.

Therapeutic effect of nimesulide on colorectal carcinogenesis in experimental murine ulcerative colitis

Background:  Patients with ulcerative colitis (UC) exhibit an increased risk for the development of cancer of the colon and rectum. Cyclooxygenase (COX)‐2 inhibitors are known to suppress sporadic colorectal cancer, but it is unknown whether selective COX‐2 inhibitors exhibit a preventive effect in UC‐associated neoplasia. This study investigated the preventive effect of nimesulide, a selective COX‐2 inhibitor, on colorectal carcinogenesis in an experimental model of murine UC.

Primary CD56+ NK/T-cell lymphoma of the rectum accompanied with refractory ulcerative colitis.

A case of primary NK/T-cell lymphoma of the rectum accompanied with ulcerative colitis (UC) in a 73-year-old man is reported. He had a 6-year history of repeated admission to our hospital for UC. Total colonoscopy performed 4 months after resolution of refractory UC complicated by cytomegalovirus colitis showed a markedly submucosal tumor in the rectum, which was histologically diagnosed as malignant lymphoma. The findings of computed tomography of the chest and abdomen, gallium scintigraphy, abdominal ultrasonography, and upper gastrointestinal endoscopy showed no abnormal lesions. Therefore, based on a diagnosis of localized rectal lymphoma with UC, proctocolectomy was performed. The resected specimen showed three submucosal tumors in the rectum with local nodal involvement. Histologically, the tumors were characterized by diffusely infiltrating sheets of large atypical lymphoid cells, which were negative for CD4, CD8, and CD20 but were positive for CD56, CD3, and granzyme B. The presence of Epstein-Barr virus (EBV) infection in neoplastic cells was shown by in situ hybridization for EBV-encoded early small RNA1 (EBER-1). Based on these findings, the patient was diagnosed with primary CD56+ NK/T-cell lymphoma of the rectum (stage IIE). This is the first case report of primary rectal NK/T-cell lymphoma accompanied with UC.

Multiple Mesenteric Panniculitis as a Complication of Sjögren's Syndrome Leading to Ileus.

Mesenteric panniculitis (MP) is a benign fibroinflammatory process characterized by the presence of fat necrosis, chronic inflammation and fibrosis in the mesentery. Although various causal factors, such as malignancy, chronic inflammatory conditions and autoimmune processes, have been identified, the precise etiology remains unknown. We herein report a rare case of MP accompanying Sjögrens syndrome in which a mass lesion and intestinal stenosis were observed simultaneously. This condition led to ileus, which was effectively treated using prednisolone.