Decreased activity of Ca(++)-ATPase and Na(+)/K(+)-ATPase during aging in humans

Aging is a biological process characterized by a progressive functional impairment which is associated with increased susceptibility to a variety of diseases. The main purpose of this study is to understand the gender-based relationship between human aging and activities of two erythrocyte membranes bound enzymes, Ca(++)-ATPase and Na(+)/K(+)-ATPase. Ca(++)-ATPase and Na(+)/K(+)-ATPase activities were determined as per the previous reports. Statistical differences were analyzed with Student's t test. Our results show a significant (p<0.0001) decrease in the Ca(++)-ATPase and Na(+)/K(+)-ATPase activities in males and females as a function of age. We also correlate the activities of ATPases with total antioxidant capacity of the plasma in term of ferric reducing ability of plasma values. The Ca(++)-ATPase and Na(+)/K(+)-ATPase activities positively correlated with ferric reducing ability of plasma value. No significant differences in the ATPase activity between males and females were observed. Decreased activity of Ca(++)-ATPase and Na(+)/K(+)-ATPase during human aging may be due to increased free radical generation which leads to oxidative stress and alter the erythrocyte membrane transport function and other activities. Our results emphasize the need to establish age-dependent reference values for membrane bound enzymes in studies involving its role in different disease conditions.