Pneumomediastinum is a frequent but minor complication during esophageal endoscopic submucosal dissection.

BACKGROUND AND STUDY AIM: Esophageal perforation caused by endoscopic submucosal dissection (ESD) induces serious pneumomediastinum. In the absence of endoscopically detected perforation, postprocedural pneumomediastinum may occur. The aim of this study was to evaluate the association between the clinical factors/courses and pneumomediastinum revealed by chest computed tomography (CT) with special reference to an exposed muscle layer during esophageal ESD. PATIENTS AND METHODS: A total of 58 patients undergoing ESD for esophageal neoplasms between February 2003 and June 2007 also underwent both chest radiography and chest CT within 1 hour after ESD. We studied the association between findings on CT scan and tumor-related and technical factors of esophageal ESD by uni- and multivariate analyses. We also analyzed the clinical factors/courses experienced by all patients. RESULTS: Pneumomediastinum was detected in 18 / 58 patients (31 %) by chest CT compared with only 1 / 58 patients (1.7 %) by chest radiography. ESD-induced exposure of the muscular layer (32 patients) was the only significant factor for pneumomediastinum (18 / 32; P < 0.0001). Clinical factors such as fever, white blood cell count, and C-reactive protein were significantly increased in the group positive for both endoscopically exposed muscular layer and pneumomediastinum (+/+, n = 18) compared with the (-/-) group (n = 26) in the early phase (day 1) after ESD. However, these factors did not affect the length of the fasting period or the length of hospital stay. CONCLUSIONS: In esophageal ESD, pneumomediastinum detected by chest CT only does not cause clinically significant complication. Endoscopic muscle exposure during ESD is a significant risk factor for pneumomediastinum, which causes mild inflammation in the early post-ESD phase.

STAT3 activation via interleukin 6 trans-signalling contributes to ileitis in SAMP1/Yit mice.

BACKGROUND AND AIMS: SAMP1/Yit mice spontaneously develops intestinal inflammation. Previously, we demonstrated that the signal transducer and activator of transcription (STAT)-3/suppressor of cytokine signalling (SOCS)-3 pathway is pivotal in human inflammatory bowel disease. In our studies in SAMP1/Yit mice, the aim was to investigate whether STAT3 activation contributes to ileitis and to examine the therapeutic effects of this signal blockade. METHODS: Intestinal expression of phospho-STAT3 in SAMP1/Yit mice and control AKR/J mice was examined by western blotting and immunohistochemistry. SOCS3 and interleukin 6 (IL-6) mRNA were determined by northern blotting and reverse transcription-polymerase chain reaction, respectively. We also examined the effects of intravenously injected hyper-IL-6, an IL-6/soluble IL-6 receptor fusion protein, and of soluble gp130-Fc, a specific inhibitor of soluble IL-6 receptor signalling, on STAT3 phosphorylation and disease severity in SAMP1/Yit mice. RESULTS: Phospho-STAT3 was expressed strongly during the disease course in SAMP1/Yit mice but only transiently in AKR/J mice. Phospho-STAT3 was localised to epithelial and mononuclear cells in the diseased intestine of SAMP1/Yit mice. SOCS3 as well as IL-6 mRNAs were expressed in affected intestine. Administration of hyper-IL-6 caused disease exacerbation and enhancement of STAT3 phosphorylation. In contrast, soluble gp130-Fc administration ameliorated the disease and suppressed STAT3 phosphorylation. CONCLUSION: STAT3 signalling is critical in the development of intestinal inflammation in SAMP1/Yit mice. Blockade of this signalling pathway by soluble gp130-Fc may have therapeutic effects in inflammatory bowel disease.

Attenuation of experimental colonic injury by thiazolidinedione agents.

OBJECTIVE: We investigated the potential use and action mechanisms of thiazolidinedione (TZD) agonists for peroxisome proliferator-activated receptor-gamma, namely pioglitazone and netoglitazone, during dextran sulfate sodium (DSS)-induced colitis in mice. METHODS: Colitis was induced by the drinking of 2.5% DSS for 7 days. In the prophylactic protocol, pioglitazone or netoglitazone was administered 2 days before the first DSS exposure and repeated daily for a total of 10 doses. In the therapeutic protocol, pioglitazone was administered 2 days after the first DSS exposure and repeated daily for a total of 10 doses. The effect of pioglitazone on proinflammatory cytokine signaling was examined both in vivo and in vitro. RESULTS: Colitis was significantly attenuated by both pioglitazone and netoglitazone in the prophylactic protocol and by pioglitazone in the therapeutic protocol. The improvement of colitis by pioglitazone was associated with decreased colonic interleukin-6, and phospho-signal transducer and activator of transcription-3 levels. In vitro experiments revealed that culturing lamina propria mononuclear cells in the presence of pioglitazone down-regulated the production of interleukin-6. CONCLUSIONS: These TZD agents should be considered for use as new therapeutic agents in intestinal inflammation such as inflammatory bowel disease. TZD-induced improvement in inflammation is explained, in part, by down-regulation of proinflammatory cytokine signaling.

Activation of c-Jun N-terminal kinase (JNK) signalling in experimentally induced gastric lesions in rats.

The c-Jun N-terminal kinase (JNK) participates in intracellular signalling cascades that mediate inflammatory responses. Therefore, the JNK signalling may be involved in gastric injury and inhibition of this pathway may form the basis of a new strategy for the treatment of gastric injury. The aim of this study was to determine whether JNK participates in the formation of gastric lesions in an experimental model. Acute gastric injury was induced in Sprague-Dawley rats by intragastric administration of 100% ethanol. The amount of phospho-JNK in the rat stomach was determined using immunohistochemistry and Western analysis. Animals received subcutaneous injections of a specific JNK inhibitor SP600125 or vehicle and the extent of mucosal damage in the stomach was determined. Western analysis revealed early phosphorylation of JNK and, to a lesser extent, p38 as well as late phosphorylation of the p42/44 extracellular signal-related kinases during the development of gastric lesions. JNK was phosphorylated in epithelial cells and in occasional mononuclear cells present at lesion sites. These cells were rarely found in samples from control specimens. Treatment with SP600125 significantly reduced the extent of gastric lesions. These findings indicate that experimental gastric injury is associated with activation of the JNK signalling pathway, and also suggest that JNK inhibitors may play a role in the treatment of gastric injury in humans.

A form of circulating interleukin-6 receptor component soluble gp130 as a potential interleukin-6 inhibitor in inflammatory bowel disease.

The presence and the role of soluble gp130, the soluble form of a component of the interleukin (IL)-6 receptor complex, were investigated in inflammatory bowel disease. The serum concentrations of soluble gp130 were increased in ulcerative colitis (active disease, median, 93.5 ng/ml; interquartile range, 26-125 ng/ml; inactive disease, 81 ng/ml, 24.8-137.3 ng/ml) and to a lesser extent in Crohn's disease (active disease, 66 ng/ml, 44.4-87.6 ng/ml; inactive disease, 63 ng/ml, 43.5-82.5 ng/ml) compared to normal controls (43 ng/ml, 27-59 ng/ml). Paired analysis of serum samples showed a decrease of IL-6 and soluble IL-6 receptor concentrations in both diseases and an increase of soluble gp130 concentrations, especially in ulcerative colitis, just after the resolution of disease exacerbation. Size fractionation of the serum revealed that a part of the IL-6 co-eluted with soluble gp130 and soluble IL-6 receptor. The IL-6-induced proliferation of murine B9 hybridoma was enhanced by recombinant soluble IL-6 receptor, whereas the proliferation was inhibited by recombinant soluble gp130. These results indicate that soluble gp130 may function as a natural inhibitor of the IL-6 actions in inflammatory bowel disease.

Diminished cytokine signalling against bacterial components in mononuclear leucocytes from ulcerative colitis patients after leukocytapheresis.

Infiltration by circulating inflammatory cells is a prominent local inflammatory feature of ulcerative colitis (UC). Several trials have suggested that leukocytapheresis by filtration can benefit patients with active UC. We investigated how this therapy might modulate the inflammatory response. Patients with active UC who were beginning repeated filtration leukocytapheresis were studied. Mononuclear cell preparations were obtained from blood before and after the first treatment, and expression of cytokine signalling components and the cell-proliferative response were analysed in vitro. Leukocytapheresis reduced lipopolysaccharide-induced production of proinflammatory cytokines (interleukin-1, -6, -8 and tumour necrosis factor-alpha, P < 0.05 for all) and activation of intracellular signalling components (nuclear factor-kappaB, mitogen-activated protein kinases, and signal transducer and activator of transcription-3), as well as surface expression of toll-like receptor-4 (P < 0.05) in mononuclear cells. The therapy also reduced the cell-proliferative response by mononuclear cells stimulated with sonicated bacterial preparations from autologous intestine (P < 0.05). These results indicate that activated mononuclear cells in the peripheral blood of patients with active UC are removed by leukocytapheresis and replaced by cells with a lower activation status. This replacement may partly explain the therapeutic benefit.

Radiographic observation of a case of gastrointestinal stromal tumor in stomach.

A case of gastrointestinal stromal tumor (GIST) in stomach was presented. Serial barium meal x-ray examinations revealed an enlarging elevated lesion on the fornix of the stomach. Tumor volume doubling time was found to be 299 days. Microscopic and immunohistochemical studies of the resected tumor disclosed GIST, uncommitted type, low grade malignant/potentially malignant. A radiographic feature of this rare type of gastric submucosal tumor was demonstrated in this report.