Characterization of a water-soluble chitosan derivative and its potential for submucosal injection in endoscopic techniques

To examine the potential of chitosan-based agents for submucosal injection in endoscopic techniques, a chitosan derivative was prepared with lactose moieties linked to the amino groups of its glucosamine units (CH-LA). After dissolving CH-LA in neutral pH solutions, including physiological saline (CH-LA-S), its response to different concentrations of anionic glycosaminoglycans and proteins in the surrounding environment was examined. The CH-LA-S form changed in the presence of sulfated glycosaminoglycans (heparin, chondroitin sulfate, and mucin) and protein (fibrinogen). High concentrations of sulfated substrates in the solution caused the formation of larger structures. In contrast, in the presence of hyaluronan, 30 mg/mL CH-LA-S did not form any large structures. Submucosal injection of 30 mg/mL CH-LA-S into extracted swine stomachs showed a strong lifting effect of the gastric mucosa. These results indicate the potential utility of CH-LA-S as a submucosal injection for endoscopic techniques such as endoscopic submucosal dissection and mucosal resection of tumors.