Mediterranean diet supplemented with coenzyme Q10 induces postprandial changes in p53 in response to oxidative DNA damage in elderly subjects

Abstract

Coenzyme Q10 (CoQ) is a powerful antioxidant that reduces oxidative stress. We explored whether the quality of dietary fat alters postprandial oxidative DNA damage and whether supplementation with CoQ improves antioxidant capacity by modifying the activation/stabilization of p53 in elderly subjects. In this crossover study, 20 subjects were randomly assigned to receive three isocaloric diets during 4 weeks each: (1) Mediterranean diet (Med diet), (2) Mediterranean diet supplemented with CoQ (Med+CoQ diet), and (3) saturated fatty acid-rich diet (SFA diet). Levels of mRNAs were determined for p53, p21, p53R2, and mdm2. Protein levels of p53, phosphorylated p53 (Ser20), and monoubiquitinated p53 were also measured, both in cytoplasm and nucleus. The extent of DNA damage was measured as plasma 8-OHdG. SFA diet displayed higher postprandial 8-OHdG concentrations, p53 mRNA and monoubiquitinated p53, and lower postprandial Mdm2 mRNA levels compared with Med and Med+CoQ diets (p < 0.05). Moreover, Med+CoQ diet induced a postprandial decrease of cytoplasmatic p53, nuclear p-p53 (Ser20), and nuclear and cytoplasmatic monoubiquitinated p53 protein (p < 0.05). In conclusion, Med+CoQ diet improves oxidative DNA damage in elderly subjects and reduces processes of cellular oxidation. Our results suggest a starting point for the prevention of oxidative processes associated with aging.

Fig. 1

Flow chart of subjects who were recruited at the beginning of the study, the number of subjects who were excluded, and the number of subjects who participated in each 4-week feeding trial. Med diet Mediterranean diet, Med+CoQ diet Mediterranean diet supplemented with CoQ, SFA diet saturated fatty acid-rich diet

Fig. 2

Fasting and postprandial plasma levels of CoQ (a) and 8-OHdG (b) and nuclear p53 (c) and cytoplasmic p53 (d) in peripheral mononuclear cells of healthy elderly subjects at the end of the three diets. Representative immunoblot of nuclear and cytoplasmatic p53, and actin. Depicted bands are different parts of the same blot stained for each antigen (e). Results are means ± SEM, n = 20. Results were analyzed using ANOVA for repeated measures. ^#p < 0.001 Med diet vs Med+CoQ diet at fasting; ⁺p < 0.001 Med+CoQ diet vs SFA diet at fasting; ^‡p < 0.001 Med diet vs SFA diet at fasting; ^§p < 0.05 Mediterranean diet vs SFA-rich diet; ^§§p < 0.05 Med+CoQ diet vs SFA diet; ^††p < 0.05 Med+CoQ diet vs Med diet; *p < 0.05 decreased postprandial of Med+CoQ diet (fasting vs 4 h). ^¥p < 0.05 increased postprandial of Med+CoQ diet (fasting vs 2 h). P1 diet effect, P2 time effect, P3 diet by time interaction, Med+CoQ Mediterranean diet supplemented with CoQ, Med Mediterranean diet, SFA saturated fatty acid-rich diet

Fig. 3

Fasting and postprandial nuclear phosphorylated p53 (Ser20) (a), cytoplasmic phosphorylated p53 (Ser20) (b), nuclear monoubiquitinated p53 (c), and cytoplasmic monoubiquitinated p53 (d) in peripheral mononuclear cells of healthy elderly subject at the end of the three diets. Representative immunoblots of nuclear and cytoplasmic p-p53, nuclear and cytoplasmic monoubiquitinated p53, and actin. Depicted bands are different parts of the same blot stained for each antigen (e). Results are mean ± SEM, n = 20. Results were analyzed using ANOVA for repeated measures. *p < 0.05 decreased postprandial Med+CoQ diet (fasting vs 4 h); ^§§p < 0.05 Med+CoQ diet vs SFA diet; ^‡p < 0.05 Med diet vs SFA diet; **p < 0.05 decreased postprandial of Med diet (fasting vs 4 h). Med+CoQ Mediterranean diet supplemented with CoQ, Med Mediterranean diet, SFA saturated fatty acid-rich diet

Fig. 4

Fasting and postprandial p53 mRNA (a), mdm2 mRNA (b), p21 mRNA (c), and p53R2 mRNA (d) in peripheral mononuclear cells of healthy elderly subject at the end of the three diets. Results are means ± SEM, n = 20. Results were analyzed using ANOVA for repeated measures. ^§p < 0.05 Med diet vs SFA diet; ^¶p < 0.05 postprandial increase with SFA diet. ^#p < 0.01 Med+CoQ diet vs Med diet at fasting. ⁺p < 0.05 Med diet vs SFA diet at fasting. ^†p < 0.05 Med diet vs SFA diet at postprandial (4 h). P1 diet effect, P2 time effect, P3 diet by time interaction, Med+CoQ Mediterranean diet supplemented with CoQ, Med Mediterranean diet, SFA saturated fatty acid-rich diet

Fig. 5

Correlation between plasma 8-OHdG concentration and the increase of mRNA p53 levels at 2 h of postprandial period (a). Correlation between nuclear p53 levels and mRNA p53 at fasting (b). Correlation between mRNA Mdm2 and nuclear p53 levels at fasting (c). Correlation between mRNA Mdm2 and nuclear monoubiquitinylated p53 levels at fasting (d). Correlation between mRNA Mdm2 and mRNA p53 at postprandial period (4 h) (e). Correlation between nuclear phosphorylated p53 (Ser20) levels and mRNA Mdm2 at postprandial period (4 h) (f)