The Activities of NADH-MethB Reductase and Glucose-6 – Phosphate Dehydrogenase (G-6-Pd) in the Red Cells of Malaria Patients

Abstract

The activities of NADH-MetHB reductase and G-6-PD were investigated in malaria patients in Calabar, Nigeria. Seventy malaria patients were selected for this study. Sixty-two age, sex – matched apparently healthy children were used as controls. Ages of subjects ranged from 6 months to 12 years (Mean = 5±1.3 years). Blood samples were collected from the patients before the commencement of treatment. The controls were confirmed to be malaria parasite negative. Blood samples were examined for the presence and type of malaria parasite. Plasmodium falciparum was the commonest infection encountered. NADH-MetHB reductase activity in malaria patients was 46% of the activity in controls. This indicates a lower enzyme activity in malaria patients than in controls (p<0.001). Severely infected and mild/moderate infected subjects showed 1.49% and 49.5% of the enzyme activity in controls respectively. This also indicates a significantly lower (p<0.001) activity of this enzyme in severe malaria than in other subjects. Glucose-6-phosphate dehydrogenase (G6PD) activity was also observed to be lower in malaria patients (83.9±47.5mU/1012 RBC) than in controls (110.5±42.1 m/U/1012 RBC). Malaria patients with severe infection had a significantly lower (p<0.001) G-6-PD activity (44.1±24.6mU/1012 RBC compared with the enzyme activity in mild/moderate infection (101±38.4mU/1012 RBC) and control subjects. It is concluded that malaria infection induces reductive changes, leading to reduced NADH-MetHB reductase activity which could consequently cause increased MetHb formation. In addition, G-6-PD activity is reduced, most significantly in severe malaria infection which may also result in decreased GSH formation. These changes may contribute significantly to their potentials to cause cell damage is apparent. The maintenance of intact reductive system in these patients and a possible correction of these factors could enhance the treatment and management of the disease.


Mary Slessor Journal of Medicine Vol.3(2) 2003: 66-71