Erythrocyte membrane alterations during ageing affect beta-D-glucuronidase and neutral sialidase in elderly healthy subjects.
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 beta-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 beta-d-glucuronidase and neutral sialidase in young and senescent erythrocytes, respectively. Overall beta-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.
Goi
G
G
Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, Via Saldini, 50-20133 Milan, Italy. giancarlo.goi@unimi.it
Cazzola
R
R
Tringali
C
C
Massaccesi
L
L
Volpe
S Russo
SR
Rondanelli
M
M
Ferrari
E
E
Herrera
C J Baquero
CJ
Cestaro
B
B
Lombardo
A
A
Venerando
B
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D016022:Case-Control Studies; D004910:Erythrocyte Membrane / Q000201:enzymology*; D005260:Female; D005966:Glucuronidase / Q000378:metabolism*; D006801:Humans; D008297:Male; D008560:Membrane Fluidity; D009439:Neuraminidase / Q000378:metabolism*
D009439:Neuraminidase; D005966:Glucuronidase