Yoshimasa Hirata

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, suppresses CXCL5 and SDF-1 and does not accelerate intestinal neoplasia formation in ApcMin/+ mice fed a high-fat diet

The relationship between type 2 diabetes mellitus and intestinal neoplasia has been shown epidemiologically. A high-fat diet (HFD) is also known to promote insulin resistance, which is a risk factor for intestinal neoplasia. Dipeptidyl peptidase-4 (DPP-4) inhibitors are used in the clinic for the treatment of type 2 diabetes and also to prolong the effects of glucagon-like peptide-1 (GLP-1). However, since the intestinotrophic hormone GLP-2 and chemokines, such as CXCL5 and stromal cell-derived factor-1 (SDF-1), are also substrates of DPP-4, DPP-4 inhibitors may increase the risk of intestinal carcinogenesis. In this study, we evaluated the impact of a DPP-4 inhibitor on intestinal tumorigenesis in ApcMin/+ mice fed a HFD. Six-week-old male ApcMin/+ mice were randomized to either a normal diet (10 kcal% fat) group, a HFD (60 kcal% fat) group, or a HFD group treated with sitagliptin (STG). The mice were euthanized nine weeks after the start of treatment. Daily treatment with STG did not increase number of intestinal tumors in the HFD group; however, this increase was not statistically significant. The mucosal concentration of total GLP-2 was significantly increased in the HFD group. The chemokine protein array showed elevated plasma concentrations of CXCL5 and SDF-1 in the HFD group. The administration of STG significantly suppressed the levels of plasma CXCL5 and SDF-1 in mice fed a HFD. Since CXCL5 expression is increased in patients with type 2 diabetes, and GLP-2, CXCL5 and SDF-1 are associated with tumor progression, DPP-4 inhibition may have potential as an agent for decreasing the risk of cancer in obese or diabetic patients.

Reocclusion after Self-Expandable Metallic Stent Placement for Relieving Malignant Colorectal Obstruction as a Palliative Treatment

Self-expandable metallic stent (SEMS) placement has been practiced in several hospitals in Japan, including ours, since January 2012. Here, we report the case of an 82-year-old Japanese man who presented to the hospital with a 1-week history of right hypochondrial pain. Computed tomography (CT) findings indicated colorectal cancer. The laboratory findings on admission indicated severe anemia (red blood cell count, 426 × 104/μL; hemoglobin, 7.9 g/dL). We performed SEMS placement because the patient refused to undergo surgery. He did not attend any of the scheduled follow-up visits after SEMS placement. However, a year and a half after the SEMS placement, the patient attended the hospital because of difficulty in passing stool. A plain abdominal CT scan showed bowel reobstruction due to the ascending colon cancer after SEMS placement. We performed an emergency operation, ascending colostomy, on the same day. Colorectal stent placement may be a good treatment option for patients who refuse to undergo conventional therapeutic treatments or in those with unresectable colorectal cancer. Patients should be carefully followed up every few months after SEMS placement because of the risk of reocclusion.

Thoracic Aorto-Esophageal Fistula Following Endovascular Aneurysm Repair

An 84-year-old woman who underwent an endovascular aneurysm repair for a thoracic aortic aneurysm six months previously presented with hematemesis. Emergency upper gastrointestinal endoscopy revealed a nonspecific esophageal ulcer (10 mm in diameter, base covered with thrombi) at a site 20 cm from the incisors (Picture 1). Hemostasis was not performed because there was no active bleeding during the endoscopic examination. Enhanced computed tomography after endoscopy revealed emphysema around the thoracic aorta (Picture 2, red arrows). The esophageal lumen was seen to be connected to the thoracic aorta through a fistula. We considered that this fistula may have been formed by the persistent inflammation caused by a stent graft that had been inserted into the thoracic aorta. Surgery was considered to be the only viable treatment; however, the patient refused to undergo surgery.

Cytomegalovirus infection in ulcerative colitis assessed by quantitative polymerase chain reaction: risk factors and effects of immunosuppressants

We investigated the risk factors of and appropriate treatment for cytomegalovirus colitis in patients with ulcerative colitis, using quantitative polymerase chain reaction analysis to detect cytomegalovirus in the colonic mucosa. Between February 2013 and January 2017, patients with exacerbated ulcerative colitis who were admitted to our hospital were consecutively enrolled in this retrospective, single-center study. Patients were evaluated for cytomegalovirus using serology (antigenemia) and quantitative polymerase chain reaction analyses of the colonic mucosa, which were sampled during colonoscopy. Of 86 patients, 26 (30.2%) had positive quantitative polymerase chain reaction results for cytomegalovirus; only 4 were also positive for antigenemia. The ages of the cytomegalovirus DNA-positive patients were significantly higher than those of negative patients (p = 0.002). The mean endoscopic score of cytomegalovirus DNA-positive patients was significantly higher than that of cytomegalovirus DNA-negative patients. Treatment with combined immunosuppressants was associated with an increased risk of cytomegalovirus. Fourteen of 15 (93.3%) cytomegalovirus DNA-positive patients who were negative for antigenemia showed a clinical response to treatment with additional oral tacrolimus, without ganciclovir. cytomegalovirus reactivation in active ulcerative colitis is associated with age and combined immunosuppressant therapy. Because additional treatment with tacrolimus was effective, patients who are negative for antigenemia and cytomegalovirus DNA-positive colonic mucosa may recover without antiviral therapy.

Augmented O -GlcNAcylation alleviates inflammation-mediated colon carcinogenesis via suppression of acute inflammation

Colon cancer prevalence is high worldwide. O-GlcNAcylation has been associated with tumor growth in various tissues, including the colon; however, its link to carcinogenesis is not fully understood. We investigated the association of O-GlcNAcylation with colon carcinogenesis using a 1,2-dimethylhydrazine/dextran sodium sulfate-induced colon carcinogenesis model in wild type and O-GlcNAc transferase-transgenic (Ogt-Tg) mice. The incidence of colon cancer was significantly lower in Ogt-Tg than in wild type mice. The colonic length was not shortened in Ogt-Tg mice, and NF-κB p65 phosphorylation was strongly suppressed, indicating that reduction of inflammation might be related to the alleviation of colon carcinogenesis. Dextran sodium sulfate-induced acute colitis mice were used to evaluate the effect of O-GlcNAcylation on inflammation at the maximal inflammation period. In Ogt-Tg mice, NF-κB p65 phosphorylation and interleukin-1β mRNA expression were suppressed. Histochemical staining demonstrated shedding of colon epithelial cells in wild type mice a few days after dextran sodium sulfate treatment, whereas they remained essentially intact in Ogt-Tg mice. There were no significant differences on histochemical staining in the remaining epithelia between groups. These data suggest that O-GlcNAcylation could prevent colon carcinogenesis through reducing acute maximum inflammation, suggesting modulation of O-GlcNAcylation as a novel therapeutic option.