Publications

PURPOSE

Colonic lipomas are benign, submucosal tumours that are usually asymptomatic. Typically, they are incidentally diagnosed during colonoscopy. Due to a low prevalence, the natural history of lipomas remains largely unknown. While large (>2 cm) lesions can cause symptoms and complications, their endoscopic treatment is not routinely recommended because of prior reports of a high rate of perforation.

METHODS

We used a standardized technique of polypectomy, using endoscopic looping to resect large colonic lipomas in 8 patients and followed their clinical outcomes.

RESULTS

The mean lipoma size was 3.8+/-1.2 cm (range 2.5-6 cm). No patient developed bleeding or perforation. On follow-up (mean=13.5 months, range 2-29), there was one small residual lesion.

CONCLUSION

Colonic lipomas larger than 2 cm can be safely and efficaciously removed using endoloop assisted polypectomy technique.

BACKGROUND

We hypothesized that laparoscopic adjustable gastric banding (LAGB) reduces weight and modulates ghrelin production, but largely spares gastrointestinal endocrine function. To examine this hypothesis, we determined plasma concentrations of appetite-control, insulinotropic, and digestive hormones in relation to LAGB.

METHODS

Twenty-four patients undergoing LAGB were prospectively enrolled. Body mass index (BMI) was measured and blood samples obtained at baseline and 6 and 12 months post-surgery. Plasma concentrations of leptin, acylated and total ghrelin, pancreatic polypeptide (PP), insulin, glucose-dependent insulinotropic peptide (GIP), active glucagon-like peptide-1 (GLP-1), gastrin, and pepsinogens I and II were measured using enzyme-linked immunoassays.

RESULTS

Median percent excess weight loss (%EWL) over 12 months was 45.7% with median BMI decreasing from 43.2 at baseline to 33.8 at 12 months post-surgery (p < 0.001). Median leptin levels decreased from 19.7 ng/ml at baseline to 6.9 ng/ml at 12 months post-surgery (p < 0.001). In contrast, plasma levels of acylated and total ghrelin, PP, insulin, GIP, GLP-1, gastrin, and pepsinogen I did not change in relation to surgery (p > 0.05). Pepsinogen II levels were significantly lower 6 months after LAGB but returned to baseline levels by 12 months.

CONCLUSIONS

LAGB yielded substantial %EWL and a proportional decrease in plasma leptin. Our results support the hypothesis that LAGB works in part by suppressing the rise in ghrelin that normally accompanies weight loss. Unchanged concentrations of insulinotropic and digestive hormones suggest that gastrointestinal endocrine function is largely maintained in the long term.

Macrophage recognition of Salmonella enterica serovar Typhimurium leads to a cascade of signaling events, including the activation of Src family and Syk kinases and the production of reactive oxygen species (ROS), which are critical for host innate defense during early stages of bacterial infection. ROS production depends on the NADPH oxidase, but little is known about the innate immune receptors and proximal adapters that regulate Salmonella-induced ROS. Herein, we demonstrate that serovar Typhimurium induces ROS through a pathway that requires both triggering receptor expressed on myeloid cells 2 (TREM2) and DAP12. This pathway is highly analogous to the pathways utilized by Fc receptors and integrins to regulate ROS production. Oral infection of mice with serovar Typhimurium demonstrates that the DAP12-dependent pathway regulates cecal colonization during early stages of Salmonella infection. Thus, DAP12 is an important regulator of Salmonella-induced ROS production in macrophages, and TREM2 is essential for linking DAP12 to the innate response to serovar Typhimurium.