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Biomarkers of exposure to vitamins A, C, and E and their relation to lipid and protein oxidation markers.Since antioxidant vitamins may affect an organism's capacity for defence against reactive oxygen species, biological markers of the dietary exposure to these vitamins is of importance. There is also a need of effect biomarkers for determining the ability of these and other antioxidants to increase the overall antioxidant capacity and decrease the oxidative damage occurring in biological samples. This review is concerned with exposure markers and markers of lipid- or protein damage following intervention with vitamins A, C and E. While there are several high quality exposure markers available it is not possible to identify functional markers of lipid or protein oxidation, which respond reliably to human dietary intervention with vitamins A, C or E.
DNA repair phenotype and dietary antioxidant supplementation.Phytochemicals may protect cellular DNA by direct antioxidant effect or modulation of the DNA repair activity. We investigated the repair activity towards oxidised DNA in human mononuclear blood cells (MNBC) in two placebo-controlled antioxidant intervention studies as follows: (1) well-nourished subjects who ingested 600 g fruits and vegetables, or tablets containing the equivalent amount of vitamins and minerals, for 24 d; (2) poorly nourished male smokers who ingested 500 mg vitamin C/d as slow- or plain-release formulations together with 182 mg vitamin E/d for 4 weeks. The mean baseline levels of DNA repair incisions were 65.2 (95 % CI 60.4, 70.0) and 86.1 (95 % CI 76.2, 99.9) among the male smokers and well-nourished subjects, respectively. The male smokers also had high baseline levels of oxidised guanines in MNBC. After supplementation, only the male smokers supplemented with slow-release vitamin C tablets had increased DNA repair activity (27 (95 % CI 12, 41) % higher incision activity). These subjects also benefited from the supplementation by reduced levels of oxidised guanines in MNBC. In conclusion, nutritional status, DNA repair activity and DNA damage are linked, and beneficial effects of antioxidants might only be observed among poorly nourished subjects with high levels of oxidised DNA damage and low repair activity.
Oxidative stress and oxidative DNA damage is characteristic for mixed Alzheimer disease/vascular dementia.Oxidative DNA damage may contribute to neuronal cell loss and may be involved in pathogenesis of some neurodegenerative diseases. We assessed the broad spectrum of oxidative DNA damage biomarkers and antioxidants in mixed Alzheimer disease/vascular dementia (MD) and in control patients. The amount of the products of oxidative DNA damage repair (8-oxo-2'-deoxyguanosine and 8-oxoguanine) excreted into urine and cerebrospinal fluid (CSF) was measured by gas chromatography/mass spectrometry with HPLC pre-purification. The level of 8-oxo-2'-deoxyguanosine in leukocytes' DNA, antioxidant vitamins and uric acid concentrations in blood plasma were analyzed by the mean of HPLC technique. For the first time we demonstrated oxidative DNA damage on the level of whole organism and in CSF of MD patients. Urinary excretion of oxidative DNA damage repair products were higher in patients with MD than in the control group. The level 8-oxoguanine in cerebrospinal fluid of MD patients almost doubled the level found in the control group. Also the concentrations of ascorbic acid and retinol in plasma were reduced in MD patients. Oxidative stress/DNA damage is an important factor that may be involved in pathogenesis of mixed dementia. It is likely that treatment of these patients with antioxidants may slow down the progression of the disease.
Urinary excretion rates of 8-oxoGua and 8-oxodG and antioxidant vitamins level as a measure of oxidative status in healthy, full-term newborns.The aim of the present study was to evaluate the oxidative status in healthy full-term children and piglets. Urinary excretion of 8-oxoGua (8-oxoguanine) and 8-oxodG (8-oxo-2'-deoxyguanosine) were determined using HPLC/GS/MS methodology and concentrations of vitamins A, C and E with HPLC technique. The levels of 8-oxoGua in urine samples were about 7-8 times higher in newborn children and piglets when compared with the level of adult subjects, while in the case of 8-oxodG the difference was about 2.5 times. The levels of vitamin C and E in umbilical cord blood of newborn children significantly depend on the concentration of these compounds in their mother's blood. However, the values of vitamin C in human's cord blood were about 2-times higher than in respective mother blood, while the level of vitamin E showed an opposite trend. The results suggest that: (i) healthy, full-term newborns are under potential oxidative stress; (ii) urinary excretion of 8-oxoGua and 8-oxodG may be a good marker of oxidative stress in newborns; and (iii) antioxidant vitamins, especially vitamin C, play an important role in protecting newborns against oxidative stress.