Background and Aims: The GI tract is innervated by the autonomic enteric nervous system, mainly composed of submucosal Meissner’s plexus and myenteric Auerbach’s plexus, which is essential for motility, blood flow regulation, and secretory functions. In vivo visualization of the esophageal enteric nervous system (EENS) during endoscopy has not been possible without invasive mucosal resection. This study aimed to visualize the EENS without mucosal resection, in vivo by using the novel probe, needle-based confocal laserinduced endomicroscopy (nCLE) with a fluorescence neuronal probe, NeuroTrace, under EUS guidance and to evaluate the feasibility of ex vivo imaging of the neuronal network in submucosal biopsy samples acquired at endoscopy.
Methods: Four Yorkshire pigs were anesthetized and examined. In vivo experiment: During endoscopy, Neuro-Trace was injected into the submucosa and muscularis propria of the middle and distal esophagus under EUS guidance, and nCLE imaging was performed. Ex vivo experiment: Submucosal tissue biopsy specimens from the porcine esophagus were obtained for ex vivo evaluation by using a “through-the-needle” forceps technique. After incubation of the samples in NeuroTrace solution, pCLE was used to visualize the EENS elements in the tissue.
Results: Imaging of the EENS network by using EUS-guided nCLE was successful, both within the submucosa and the muscularis propria, and clearly visualized neuronal cells, glial cells, nerve bundles, and nerve fibers provided distinctive image patterns with excellent imaging quality. The use of the “through-the-needle” forceps technique achieved ex vivo images similar to those acquired in vivo.
Conclusions: EUS-guided in vivo imaging of the enteric nervous system is feasible without mucosal resection and provides a novel ex vivo imaging alternative for human application. These novel, minimally invasive imaging approaches could be of tremendous diagnostic value to better characterize and explore the EENS of the GI tract.