Article

Erythrocyte membrane alterations during ageing affect β-d-glucuronidase and neutral sialidase in elderly healthy subjects

Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, Via Saldini, 50-20133 Milan, Italy; Department of Preclinical Sciences, L.I.T.A. Vialba, University of Milan, Italy; Department of Internal Medicine and Medical Therapy, School of Endocrinology and Metabolism and Chair of Geriatrics, ‘Instituto Santa Margherita’, University of Pavia, Italy
Experimental Gerontology DOI:10.1016/j.exger.2004.08.013 pp.219-225

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.

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    Rashmi Jha, Syed Ibrahim Rizvi
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Keywords

Activity differences
 
antioxidant defenses
 
biological age
 
distinct plasma membrane micro-domains
 
elder people
 
elderly
 
elderly subjects
 
erythrocyte membrane fluidity
 
erythrocytes
 
higher oxidative stress
 
membrane glycohydrolases
 
neutral sialidase
 
neutral sialidase levels
 
plasma hydroperoxide levels
 
possible role
 
senescent erythrocytes
 
signaling praecox membrane alterations
 
young subjects
 
β-d-glucuronidase
 
β-d-glucuronidase decreases