Evidence That Hepatic Crystalline Deposits in a Patient with Protoporphyria Are Composed of Protoporphyrin

Abstract

The livers of patients with protoporphyria and hepatic disease typically contain pigment crystals which may be a factor in the pathogenesis of liver injury. We isolated and characterized these crystals from a patient who developed hepatic failure and underwent liver transplantation. The prophyrin concentration in the liver was 516 micrograms/g wet weight (normal is a trace amount), over 99% of which was protoporphyrin. Through a discontinuous sucrose density gradient, followed by tissue digestion with deoxycholate, pigment crystals were obtained that had ultrastructural features like those in the whole liver section. After the crystals were dissolved in perchloric acid-methanol, their fluorescence emission and excitation spectra were identical to those of an extract of whole liver tissue and to a protoporphyrin standard. This provides evidence that the pigment crystals in livers of patients with protoporphyria and hepatic disease are composed of protoporphyrin.