Background and study aims: Adequate bowel preparation is key for the optimal quality of colonoscopy. The sodium
phosphate laxatives used for preparation may induce gastric injuries. However, in
vivo studies monitoring the effects of sodium phosphate on the gastric mucosa are
currently lacking. We aimed to characterize the effects of sodium phosphate tablets
(Colokit®; Mayoly Spindler, Chatou, France) on the gastric mucosa in a large-animal
model.
Methods: Fourteen anesthetized pigs were used for this study. Fundic mucosal sites were analyzed
at 1.5, 24, and 72 hours after the endoscopically guided application of sodium phosphate
tablets (NaPT) and placebo tablets (PlaT) and were compared with unexposed sites.
Different mucosal parameters were assessed with white light endoscopy, probe-based
confocal laser endomicroscopy (pCLE), histology, and ex vivo permeability measurements.
Results: At 90 minutes after the application of NaPT, significant increases in epithelial
irregularity and crypt pit intensity were observed with pCLE. These microscopic lesions
persisted at 24 hours but were resolved at 72 hours. In addition, white light endoscopy
revealed local exanthema in 57 % of the animals at 1.5 hours after NaPT application.
Such lesions were observed in 22 % of the pigs at 24 hours and disappeared at 72 hours
after application. After 1.5 hours, PlaT induced a slight but significant increase
in epithelial irregularity, as well as architectural scores that were significantly
lower than the ones induced by NaPT and that disappeared after 72 hours.
Conclusions: The direct and prolonged gastric application of NaPT in pigs can induce acute superficial
macroscopic and microscopic injuries that are reversible within 72 hours.