Affiliations: Department of Mental Health and Alcohol Research,
National Public Health Institute, Helsinki, Finland | Department of Anatomy, University of Tampere, Tampere,
Finland | Department of Respiratory Medicine, University of
Tampere, Tampere, Finland
Abstract: Oxidative damage to DNA and other macromolecules accumulates with
age and has been postulated to be one of the major forms of endogenous damage
leading to aging and has been implicated also in initiation of cancer and over a
hundred other diseases. The human body has developed an antioxidant (AOX)
defense system which contains enzymatic, metal chelating, and free radical
scavenging properties. Thus, it is essential to consider the concentration of
all AOXs in plasma and CSF when investigating the relationship between diet,
oxidative stress, and disease. In the present study a luminometric TRAP-method
(total peroxyl radical-trapping potential) was used to determine the activity
of all chain breaking AOXs in several clinical states. We have measured TRAP of
plasma, cerebrospinal fluid (CSF) and of low density lipoprotein (LDL,
TRAPLDL), and the concentrations of main AOX-components (uric acid, protein
SH-groups, a-tocopherol, ascorbic acid, ubiquinone and the fraction of unknown
antioxidants) to study the effect of: 1) aging, 2) acute infection, 3)
diabetes, 4) immobilization and 5) cancer. TRAP of CSF is five times lower than
of plasma, mainly due to the low urate concentration in CSF. We have observed
that plasma antioxidant defenses respond to the basic metabolic rate and the
challenges caused by physiological or pathological stress: i) in a healthy
normal population TRAP and TRAPLDL change with age and a substantial proportion
of TRAP cannot be attributed to any known AOXs thus indicating the existence of
unmeasured an unidentified antioxidant(s); ii) during acute infection and
immobilization the exogenous AOXs (vitamin C and E) remained unchanged, whereas
the activity of unidentified AOXs of plasma declined sharply; iii) in those
NIDDM patients with coronary heart disease plasma TRAP is reduced. In
conclusion, TRAP has revealed important information for evaluating the AOX
status of human plasma, CSF and LDL. According to our studies, important,
possibly endogenous AOXs still remain to be identified.
Keywords: antioxidants, total peroxyl radical-trapping potential, aging, cancer, chemiluminescence
