Enhanced Functional Recovery in MRL/MpJ Mice after Spinal Cord Dorsal Hemisection

Adult MRL/MpJ mice have been shown to possess unique regeneration capabilities. They are able to heal an ear-punched hole or an injured heart with normal tissue architecture and without scar formation. Here we present functional and histological evidence for enhanced recovery following spinal cord injury (SCI) in MRL/MpJ mice. A control group (C57BL/6 mice) and MRL/MpJ mice underwent a dorsal hemisection at T9 (thoracic vertebra 9). Our data show that MRL/MpJ mice recovered motor function significantly faster and more completely. We observed enhanced regeneration of the corticospinal tract (CST). Furthermore, we observed a reduced astrocytic response and fewer micro-cavities at the injury site, which appear to create a more growth-permissive environment for the injured axons. Our data suggest that the reduced astrocytic response is in part due to a lower lesion-induced increase of cell proliferation post-SCI, and a reduced astrocytic differentiation of the proliferating cells. Interestingly, we also found an increased number of proliferating microglia, which could be involved in the MRL/MpJ spinal cord repair mechanisms. Finally, to evaluate the molecular basis of faster spinal cord repair, we examined the difference in gene expression changes in MRL/MpJ and C57BL/6 mice after SCI. Our microarray data support our histological findings and reveal a transcriptional profile associated with a more efficient spinal cord repair in MRL/MpJ mice

EUS-Guided Gallbladder Drainage

High-risk non-surgical candidates with acute cholecystitis are traditionally treated with the placement of a percutaneous cholecystostomy tube. However, in recent years, transmural gallbladder drainage via an endoscopic ultrasound-guided approach (EUS-GBD) has emerged as a feasible and potential equally efficacious option that obviates the need for an external drainage catheter. Among expert endoscopists, technical and clinical success rates for EUS-GBD are greater than 90% with similar adverse event rates to percutaneous drainage. Early adopters of EUS-GBD used plastic or fully covered metal self-expandable metal biliary stents (FCSEMS), but more recently, the use of a lumen-apposing metal stent (LAMS) has become widespread due to ease of deployment and lower concern for biliary leakage. Furthermore, LAMS provides continued access to the gallbladder for cholecystoscopy or other advanced interventions such as stone removal. Nevertheless, EUS-GBD remains a relatively new procedure and optimal techniques and best practices are still being defined. As such, endoscopists have yet to reach consensus on issues such as optimal location of drainage (transgastric vs. transduodenal), ideal duration for stents to be left in, and whether patients should receive routine cholecystectomy after resolution of symptoms. Until prospective trials address these issues, EUS-GBD should only be reserved for carefully selected patients in tertiary care centers

Animal models of axon regeneration after spinal cord injury

With advances in genetic and imaging techniques, investigating axon regeneration after spinal cord injury in vivo is becoming more common in the literature. However, there are many issues to consider when using animal models of axon regeneration, including species, strains and injury models. No single particular model suits all types of experiments and each hypothesis being tested requires careful selection of the appropriate animal model. in this review, we describe several commonly-used animal models of axon regeneration in the spinal cord and discuss their advantages and disadvantages