Low activity of superoxide dismutase and high activity of glutathione reductase in erythrocytes from centenarians

Objective: to compare the activities of antioxidative enzymes in erythrocytes between centenarians and a younger group of elderly subjects. Design: cross-sectional study. Setting: county of Funen, Denmark. Subjects: 41 centenarians aged between 100 and 105 years and 52 community control subjects aged between 60 and 79 years. Measurements: enzyme activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase, catalase and glutathione reductase (GR) in erythrocytes. Functional capacity among the centenarians was evaluated by Katz' index of activities of daily living, the Physical Performance Test and Mini-Mental State Examination. Results: the mean CuZn-SOD activity was significantly lower and the mean GR activity was significantly higher in centenarians than in the group of elderly people. The centenarians with the lowest cognitive and physical functional capacity and who did not survive at least 1 year after blood sampling tended to have the lowest CuZn-SOD activities. The range of GR activity was shifted toward higher values in the centenarian group than in the younger group and those centenarians having the best functional capacity tended to have the highest GR activity. Conclusions: CuZn-SOD activity is decreased in centenarians, probably because of reduced demand for the enzyme at lower metabolic rate and oxygen consumption. Subjects with high GR activity occur more frequently among centenarians than expected, possibly due to their better survival. The role of GR in disease prevention and as a predictor for longevity deserves to be further explored.