Erythrocyte membrane alterations during ageing affect β-d-glucuronidase and neutral sialidase in elderly healthy subjects
ABSTRACT In this study, a comparison between elderly (>70 years) and young subjects reveals that elder people are subject to a higher oxidative stress, which causes an increase in plasma hydroperoxide levels (18%) and a decrease in antioxidant defenses (25%). Moreover, the marked decrease of the erythrocyte membrane fluidity observed in elderly subjects was likely to affect the behavior of some membrane glycohydrolases. In fact, a significant decrease of β-d-glucuronidase and neutral sialidase (30 and 50%, respectively) was detected. Activity differences were also observed when erythrocytes were further distinguished according to their biological age. Striking differences between young and elderly subjects were observed for β-d-glucuronidase and neutral sialidase in young and senescent erythrocytes, respectively. Overall β-d-glucuronidase decreases with the subjects' age, while neutral sialidase levels are higher in the elderly. This is presumably due to the localization of these enzymes in distinct plasma membrane micro-domains, which are differently peroxidized. A possible role of these enzymes in signaling praecox membrane alterations has also been evidenced.
Article: Age-dependent decline in erythrocyte acetylcholinesterase activity: correlation with oxidative stress.[show abstract] [hide abstract]
ABSTRACT: Oxidative stress hypothesis offers a mechanism for the aging process and its involvement in other pathologies such as diabetes and neurodegenerative diseases like Alzheimer. AChE activity in erythrocytes may be considered as a marker of central cholinergic status. The present study was undertaken to (i) determine the activity of erythrocyte AChE as a function of human process (ii) correlate AChE activity with oxidative stress during human aging. Blood was collected from healthy subjects (n = 37) 22-82 years. Erythrocyte AChE activity, MDA and plasma antioxidant capacity in terms of FRAP was measured spectrophotometrically. There was a marked decrease in AChE activity with increasing age. The reduction in activity of AChE correlated well with increased lipid peroxidation and a decrease in FRAP values. Decreased antioxidant defense, and alteration in membrane rheology during aging process both may contribute towards decreased activity of AChE in erythrocyte membrane. This finding may help in explaining the neuronal complications taking place under conditions of oxidative stress, aging, and dementia.Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia 09/2009; 153(3):195-8.