Increased urinary coproporphyrin excretion observed in patients with differently staged Hodgkin's disease treated...

It has been reported that patients with Hodgkin's disease (HD) show altered porphyrin metabolism, and suggested that the cause is the neoplastic process itself. If this is true, disease progression should be associated with higher levels of porphyrin excretion. The aim of this study was to evaluate urinary coproporphyrin levels in patients with Hodgkin's disease at different stages. As many of the patients received chemotherapy, another aim was to verify experimentally whether chemotherapeutic agents might increase porphyrin levels in rabbits. All of the patients had above-normal urinary coproporphyrin levels. On the other hand, rabbits receiving the porphyrin precursor 5-aminolevulinic acid (5-ALA), and also treated with doxorubicin, showed very high plasma porphyrin levels. The increased levels of urinary coproporphyrins seem to be due to the disease itself, since the patients in stages III and IV had higher excretion values, presumably due to biochemical heme synthesis lesions that lead to the availability of the porphyrin precursor, as well as coproporphyrin accumulation and excretion. The altered porphyrin synthesis may be attributable to the cytotoxic oxygen species generated in the presence of NADH and iron. As the patients also received extensive chemotherapy regimes, the altered porphyrin metabolism may be affected by antineoplastic treatment generating oxygen reactive radicals. The alterations in porphyrin metabolism induced by chemotherapeutic agents appear to be demonstrated in rabbits in which doxorubicin increases porphyrin synthesis after porphyrin precursor treatment.