Ubiquinol reduces gamma glutamyltransferase as a marker of oxidative stress in humans

Abstract

BackgroundThe reduced form of Coenzyme Q10 (CoQ10), ubiquinol (Q10H2), serves as a potent antioxidant in mitochondria and lipid membranes. There is evidence that Q10H2 protects against oxidative events in lipids, proteins and DNA. Serum gamma-glutamyltransferase (GGT) activity is associated with cardiovascular diseases. In a physiological range, activity of GGT is a potential early and sensitive marker of inflammation and oxidative stress.In this study, we first examined the relationship between CoQ10 status and serum GGT activity in 416 healthy participants between 19 and 62 years of age in a cross-sectional study (cohort I). In the second step, 53 healthy males (21–48 years of age; cohort II) underwent a 14-day Q10H2 supplementation (150 mg/d) to evaluate the effect of Q10H2 supplementation on serum GGT activity and GGT1 gene expression.FindingsThere was a strong positive association between CoQ10 status and serum GGT activity in cohort I. However, a gender-specific examination revealed differences between male and female volunteers regarding the association between CoQ10 status and serum GGT activity. Q10H2 supplementation (cohort II) caused a significant decrease in serum GGT activity from T0 to T14 (p < 0.001). GGT1 mRNA levels declined 1.49-fold after Q10H2 supplementation. Of note, other liver enzymes (i.e., aspartate aminotransferase, AST) were not affected by Q10H2 supplementation.ConclusionsCoQ10 level is positively associated with serum GGT activity. Supplementation with Q10H2 reduces serum GGT activity. This effect might be caused by gene expression. Overall, we provide preliminary evidence that higher Q10H2 levels improve oxidative stress via reduction of serum GGT activity in humans.Trial registrationCurrent Controlled Trials ISRCTN26780329.

Persistence of the benefit of an antioxidant therapy in children and teenagers with Down syndrome

“…A possible explanation for this result might be a consequence of the increased GSH levels (ffi39%), since GGT promotes the turnover of GSH levels (Halliwell & Gutteridge, 2007). The vitamin E levels remained fairly constant in t 0 compared to controls, thus suggesting that the increased levels of GSH and UA are indeed playing their important role as ROS scavengers, since UA is responsible for approximately 60% of plasma ROS elimination, therefore preserving vitamin E plasma levels (Drozdz et al, 1998;Onur et al, 2014).…”

Functions of Coenzyme Q10 Supplementation on Liver Enzymes, Markers of Systemic Inflammation, and Adipokines in Patients Affected by Nonalcoholic Fatty Liver Disease: A Double-Blind, Placebo-Controlled, Randomized Clinical Trial

“…In our study, although serum leptin levels in the CoQ10-treated group were marginally reduced, this difference was not statistically significant compared to the control group, and it may be due to the low dose of CoQ10 and the short period of the study. Asker showed that coadministration of CoQ10 for 8 weeks in mice with monosodium glutamate modulated leptin gene expression [14] due to its role as a modulator of gene expression and inflammatory processes [34]. However, our literature review did not find any human studies in regard to this issue.…”

“…In a similar study, Yuvaraj et al showed that coadministration of CoQ10 and B vitamins (riboflavin and niacin) for 90 days reduced the serum activity levels of liver-related enzymes (i.e., GGT and AST) in Tamoxifen-treated women with breast cancer [35]. In another study, Onur et al [34] reported that 2 weeks' supplementation with 150 mg/day of CoQ10 in healthy subjects significantly reduced serum GGT activity as well as GGT1 gene expression. In their cross-sectional study, they found that GGT levels were strongly and positively associated with CoQ10 status.…”

“…The finding of the current study showed that CoQ10 supplementation for 12 weeks significantly decreases serum AST and GGT levels in patients with NAFLD compared to the control group but has no effect on serum ALT levels and AAR. Because liver enzymes GGT and AST are related to oxidative stress and elevated all-cause mortality [34], we assumed that the effectiveness of CoQ10 on serum GGT and AST activity may be specific for the oxidative stress suppressing effect of Q10 [34]. In a similar study, Yuvaraj et al showed that coadministration of CoQ10 and B vitamins (riboflavin and niacin) for 90 days reduced the serum activity levels of liver-related enzymes (i.e., GGT and AST) in Tamoxifen-treated women with breast cancer [35].…”

The Effects of Dark Chocolate Consumption on Lipid Profile, Fasting Blood Sugar, Liver Enzymes, Inflammation, and Antioxidant Status in Patients with Non-Alcoholic Fatty Liver Disease: A Randomized, Placebo-Controlled, Pilot study

“…One possible reason might be the oxidative stress suppressing effects of DC. Because liver enzyme AST is related to oxidative stress and elevated all-cause mortality [39] . In this regard, Abrokwah et al showed that oral gavage of aqueous cocoa suspension (1 ml/day) for 48 days had no effects on AST, ALT and Alkp in rat [40] .…”