The over-the-scope clip system--a novel technique for gastrocutaneous fistula closure: the first North American experience.

BACKGROUND: The mainstay of therapy for gastrocutaneous (GC) fistulas has been surgical intervention. However, endoclips are currently used for management of perforations and fistulas but are limited by their ability to entrap and hold the tissue. OBJECTIVE: To report the first North American experience with a commercially available over-the-scope clip (OTSC) device, a novel and new tool for the endoscopic entrapment of tissue for the closure of fistula and perforations. METHODS: The present single-centre study was conducted at a tertiary referral academic gastroenterology unit and centre for advanced therapeutic endoscopy and involved patients referred for endoscopic treatment for the closure of a GC fistula. The OTSC device was mounted on the tip of the endoscope and passed into the stomach to the level of the fistula. The targeted site of the fistula was grasped with the tissue anchoring tripod and pulled into the cap with concomitant scope channel suction. Once the tissue was trapped in the cap, a 'bear claw' clip was deployed. RESULTS: The patients recovered with fistula closure. No complication or recurrence was noted. Fistula sizes >1 cm, however, were difficult to close with the OTSC system. The length of stay of the bear claw clip at the fistula site is unpredictable, which may lead to incomplete closure of the fistula. CONCLUSION: Closure of a GC fistula using a novel 'bear claw' clip system is feasible and safe.

Endothelial cells stimulate self-renewal and expand neurogenesis of neural stem cells.

Neural stem cells are reported to lie in a vascular niche, but there is no direct evidence for a functional relationship between the stem cells and blood vessel component cells. We show that endothelial cells but not vascular smooth muscle cells release soluble factors that stimulate the self-renewal of neural stem cells, inhibit their differentiation, and enhance their neuron production. Both embryonic and adult neural stem cells respond, allowing extensive production of both projection neuron and interneuron types in vitro. Endothelial coculture stimulates neuroepithelial cell contact, activating Notch and Hes 1 to promote self-renewal. These findings identify endothelial cells as a critical component of the neural stem cell niche.