RESUMO
BACKGROUND: Conflicting results were reported about the efficacy of vitamin E (E) treatment in porphyria cutanea tarda (PCT). We conducted a study in PCT patients to investigate whether E treatment has any additional beneficial effects compared with phlebotomy (P) treatment alone on rheological and oxidative stress parameters. METHODS: Twenty three patients with sporadic PCT in clinical remission and 10 healthy control patients were studied. All patients were treated with P prior to the study until clinical remission was achieved. Baseline routine laboratory [blood glucose, serum lipids, C-reactive protein (CRP), iron metabolism indices, liver function tests], oxidative stress [serum thiobarbituric acid reactive substances (TBARS), plasma H-donor activity, plasma free SH-groups, erythrocyte glutathion peroxidase activity] and rheological parameters (whole blood and plasma viscosity, cell transit time, clogging rate) were measured in both groups. Then all PCT patients received E (tocopherol acetate) 200 mg/day for 8 weeks and at the end of treatment measurements identical to those performed at baseline were repeated. RESULTS: Increased urine uroporphyrin, serum CRP, TBARS concentrations, whole blood and plasma viscosity and decreased plasma H-donor activity, free SH-group level, erythrocyte glutathione peroxidase activity were detected in PCT patients treated with P alone compared with control group consistent with residual oxidative stress in PCT patients. E treatment decreased urine uroporphyrin and serum TBARS concentrations; increased plasma H-donor activity and did not influence whole blood and plasma viscosity compared with P treatment alone. CONCLUSIONS: E treatment reduced the residual oxidative stress and did not influence increased plasma and whole blood viscosity present in PCT patients receiving P treatment prior to clinical remission.