Direct contribution of obesity to oxidative damage to macromolecules.

BACKGROUND: Obesity constitutes a common modifiable risk factor for certain non-communicable diseases (NCDs) associated with enhanced oxidative stress. OBJECTIVES AND METHODS: The aim of the study was to examine serum concentrations of malondialdehyde + 4-hydroxyalkenals (MDA+4-HDA), as an index of lipid peroxidation (LPO), and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) concentration in peripheral blood lymphocytes, as an index of nuclear DNA damage, in overweight and obese adult patients. LPO and 8-oxodG, as well as clinical and laboratory parameters, which are frequently affected by obesity, were evaluated in 58 overweight and obese adult patients, and in 20 healthy volunteers. RESULTS: Both LPO and 8-oxodG levels were increased in overweight and obese patients, with further increase observed with the increasing body mass index (BMI). LPO correlated positively with body mass, BMI, waist circumference, hip circumference, waist:hip ratio, systolic or diastolic blood pressure, glucose, C-reactive protein and ferritin concentrations. 8-oxodG correlated positively with body mass, BMI, hip circumference and triglyceride concentration, whereas it correlated negatively with iron concentration. Expectedly, positive correlation between LPO and 8-oxodG was also found. CONCLUSIONS: BMI constituted the only independent determinant (predictor) of LPO in overweight and obese patients. Consistently, LPO did constitute the only independent determinant of obesity. Overweight and obesity in adults are directly associated with increased oxidative damage to macromolecules.

External hydrogen peroxide is not indispensable for experimental induction of lipid peroxidation via Fenton reaction in porcine ovary homogenates.

OBJECTIVE: Substrates of Fenton reaction (Fe(2+)+H(2)O(2)-->Fe(3+)+*OH+OH-) may be used to experimentally induce oxidative damage to macromolecules. The study aimed at evaluating effects of Fe(2+) and/or H(2)O(2) on lipid peroxidation in porcine ovary homogenates. MATERIALS AND METHODS: Ovary homogenates were incubated in the presence of either H2O2 (100, 50, 25, 10, 5.0, 2.5, 1.0, 0.5, 0.25, 0.01, 0.001 mM) or FeSO(4) (Fe2+) (300, 150, 75, 30, 15, 7.5, 3.0, 1.5, 0.75 microM), or of those two factors used together: Fe(2+) (30 microM) plus H(2)O(2) (concentrations as above), or H(2)O(2) (0.5 mM) plus Fe(2+) (concentrations as above). The concentration of malondialdehyde+4-hydroxyalkenals constituted the lipid peroxidation index. RESULTS: H(2)O(2) alone did not affect lipid peroxidation in porcine ovary homogenates at all, whereas Fe(2+) (300, 150, 75, 30, and 15 microM) alone increased lipid peroxidation in a concentration dependent manner. When Fe(2+) and H(2)O(2) were applied together, lipid peroxidation increased significantly without any concentration related effect of H(2)O(2), but with a clear concentration dependent effect of Fe(2+); the damaging effect of Fe(2+), used together with H(2)O(2), was the same as the one, obtained after Fe(2+) was applied alone. CONCLUSIONS: In conclusion, external H(2)O(2) is not indispensable for experimental induction of lipid peroxidation by Fenton reaction in porcine ovary homogenates.