Impairment of plasma nitric oxide availability in senescent healthy individuals: apparent involvement of extracellular superoxide dismutase activity.
To verify the potential involvement of the age-dependent modifications of EC-SOD activity in the impairment of plasma NO availability with advancing age, 40 healthy men divided into 4 age groups for the purpose of comparison (young: 27.4 +/- 1.5 years; middle: 50.8 +/- 2.2, years; old: 70.0 +/- 1.8 years; very old: 86.1 +/- 1.1 years) were enrolled in this study. Plasma samples were used for measurements of the stable end-product nitrite/nitrate (NOx), as an expression of NO availability, EC-SOD activity, thiobarbituric acid reactive substances (TBARS) as a marker of lipid peroxidation, low density lipoprotein (LDL) copper-mediated oxidation in vitro and total antioxidant capacity (TEAC). Our results indicated a significant age-related progressive decrease of plasma NOx content and EC-SOD activity and their values were positively correlated (r = 0.713, p < 0.001). Increased TBARS amount together with reduced lag time for in vitro oxidation of LDL and decreased content of TEAC were observed with advancing age. Finally, EC-SOD values were negatively correlated with plasma TBARS values (r = -0.855, p < 0.001). Findings of the present study suggest that the decrease of antioxidant defence strategies play a primary role by compromising NO availability in normally aged individuals, particularly through a progressive decrease of EC-SOD activity.
Di Massimo
C
C
Area of Human Physiology, Department of STB, University of L'Aquila, Italy.
Lo Presti
R
R
Corbacelli
C
C
Pompei
A
A
Scarpelli
P
P
De Amicis
D
D
Caimi
G
G
Tozzi Ciancarelli
M G
MG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D006801:Humans; D015227:Lipid Peroxidation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000097:blood* / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis*
D017392:Thiobarbituric Acid Reactive Substances; D009569:Nitric Oxide; C441642:SOD3 protein, human; D013482:Superoxide Dismutase