Antioxidants restore protoporphyrinogen oxidase in variegate porphyria patients.

BACKGROUND: Variegate porphyria (VP) is the result of decreased protoporphyrinogen oxidase (PPOX) activity and results in the accumulation of porphyrins and porphyrin precursors. Our aims were to analyse the basal antioxidant defences and oxidative damage markers and the effects of a diet supplementation with vitamins E and C on the oxidant/antioxidant status and PPOX gene expression in lymphocytes of variegate porphyria (VP) patients. MATERIALS AND METHODS: Twelve women affected by VP and 12 control women participated in a randomized and double-blind crossover study. Each participant took either 50 mg/day vitamin E and 150 mg/day vitamin C or a placebo for 6 months. RESULTS: Lymphocyte PPOX gene expression, together with catalase and glutathione peroxidase activities, was reduced in VP women. No differences were observed in the levels of malondialdehyde and protein carbonyl derivatives. Stimulated lymphocyte H2 O2 production was higher in porphyric women. Supplementation with antioxidant vitamins increased PPOX expression in VP patients. Glutathione reductase (GRd) and superoxide dismutase (SOD) activities were higher in the treatment groups. CONCLUSIONS: Lymphocytes from VP patients show reduced PPOX expression and present a greater susceptibility to producing H2 O2 and impaired H2 O2 detoxifying mechanisms. Supplementation with vitamins E and C restores PPOX expression in VP patients and enhances GRd and SOD activity, suggesting the potential benefits of a diet rich in vitamins E and C in these patients.

Impaired lymphocyte mitochondrial antioxidant defences in variegate porphyria are accompanied by more inducible reactive oxygen species production and DNA damage.

This study aimed to analyse lymphocyte reactive oxygen species (ROS) production and detoxification mechanisms and the appearance of oxidative damage in variegate porphyria (VP) patients. Twelve women affected by VP and 12 pair-matched healthy control women participated in the study. VP women presented impaired expression of the mitochondrial proteins protoporphyrinogen oxidase, uncoupling protein-3, Bcl-2 and sirtuin 3. Lymphocytes from VP women presented higher H(2)O(2) production than controls after stimulation with phorbol myristate acetate. The inhibition of H(2)O(2) production after in vitro lymphocyte treatment with myxothiazol pointed towards complex III of the mitochondrial respiratory chain as the main contributor of the higher ROS production in porphyric subjects. No differences were observed between VP and control subjects in the levels of DNA damage, assessed by the comet assay method in un-treated lymphocytes. However, DNA damage, expressed both as a percentage of DNA in tail and as the tail moment, was greater in VP women than controls after lymphocyte treatment with H(2)O(2). In conclusion, lymphocytes from VP women showed impaired expression of mitochondrial antioxidant defences but no significant signs of oxidative stress were evidenced in basal, non-stressing conditions; however, lymphocytes of VP women were more susceptible to producing mitochondrial ROS and to suffering oxidative damage when submitted to stressful situations.

Variegate porphyria induces plasma and neutrophil oxidative stress: effects of dietary supplementation with vitamins E and C.

Our aim was to analyse the influence of variegate porphyria (VP) on the antioxidant defenses and markers of oxidative damage and inflammation in plasma and neutrophils and the effects of dietary supplementation with vitamins E and C on these parameters in plasma, neutrophils and erythrocytes. Twelve women affected by VP and twelve pair-matched healthy control women participated in a double-blind crossover study. Each participant took 50 mg/d of vitamin E and 150 mg/d of vitamin C, or a placebo, for 6 months, by consuming an almond-based beverage as the vehicle. Women affected by VP presented higher C-reactive protein and malondialdehyde (MDA) circulating levels. Plasma antioxidant defenses were not different between porphyric and control women. Neutrophils from VP women presented decreased catalase (CAT) and glutathione reductase (GR) activities together with increased protein carbonyl levels. Reactive oxygen species (ROS) production from stimulated neutrophils was also higher in porphyric women than their controls. Dietary supplementation was effective in increasing alpha-tocopherol levels in neutrophils and in reducing MDA levels in plasma. Erythrocyte CAT and GR activities were enhanced by the enriched beverage only in the control subjects. In conclusion, women affected by VP present a situation of inflammation, plasma oxidative damage and neutrophils more primed to the oxidative burst, with decreased antioxidant activities and increased ROS production capabilities and protein oxidative damage. Dietary supplementation with vitamin E (50 mg/d) and vitamin C (150 mg/d) for 6 months decreased plasma oxidative damage and enhanced the erythrocyte activities of CAT and GR.

Enzyme antioxidant defences and oxidative damage in red blood cells of variegate porphyria patients.

Variegate porphyria is the result of decreased protoporphyrinogen oxidase (PPOX) activity, the penultimate enzyme of haem biosynthesis. Haem precursors can produce free radicals and activate oxygen-inducing oxidative stress. Our aim was to analyse the effects of variegate porphyria on haemoglobin levels, antioxidant enzyme activities and oxidative damage in circulating erythrocytes. Twelve women affected by variegate porphyria and 12 control healthy women participated in the study. Women affected by variegate porphyria presented reduced PPOX content and delta-aminolevulinic acid dehydratase activity in erythrocytes. Haemoglobin content and mean corpuscular volume were higher in the porphyric group. Erythrocyte glutathione reductase and superoxide dismutase activities and catalase content were higher in porphyric women, although MDA levels were also higher in the erythrocytes of the porphyric group. In conclusion, the determination of PPOX could be a useful method to detect variegate porphyria. Despite having higher antioxidant defences, erythrocytes of porphyric women have greater oxidative damage and higher corpuscular volume, which are both indices of a situation of higher oxidative stress.