Localization of Hematoporphyrin Derivative in Injured Bladder Mucosa. An Experimental Study

Abstract

Hematoporphyrin derivative [HpD], a fluorescent mixture of porphyrins, has the putative property of being retained in neoplastic tissue after systemic administration. This preferential retention is the basis for the use of this agent as a tumor localizer and tumor photosensitizer. The retention of hematoporphyrin derivative in non-neoplastic, but regenerating, urothelium was not reported. Thermal urothelial injury was induced in Fischer 344 rats. Animals were then injected i.v. with hematoporphyrin derivative at 3 days, 1, 2, 3 and 6 wk after injury. Photography under UV illumination was used to detect porphyrin fluorescence in the bladder mucosa. Up to 3 wk afer injury, porphyrin fluorescence was detectable in areas of inflammation and hyperplasia around the area of injury. In this experimental model, HpD fluorescence is not specific for neoplasia.