Fluorescence tissue distribution of methylene blue used for photodynamic therapy of Helicobacter Pylori

Helicobacter pylori is associated with a wide range of pathologies in the upper gastrointestinal tract. Current treatments employing antibiotics are disappointing, and an endoscopic PDT might offer a better alternative. Methylene blue is a widely known histological dye and has been in use for photodynamic therapy experimentally for some years. A prospective application of MB is photosensitization of Helicobacter pylori, but little is known about its effect with light on normal mucosa of the stomach. We studied the fluorescence microscopy of the stomachs of 3 ferrets which had been sensitized by oral route with three different concentrations of MB 1 hour prior to sacrifice. MB at all doses was seen to concentrate on the surface of the mucosa and shows little deeper penetration. As Helicobacter lie on the superficial mucosa, this study suggests that oral dosing with MB should sensitize these bacteria. These findings are an important preliminary to an in vivo trial of PDT for the treatment of H pylori.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.