ubiquinol and Carcinoma--Hepatocellular

To assess the degree of oxidative stress, we measured plasma ubiquinone-10 percentage (%CoQ-10) in total amounts of ubiquinone-10 in patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma, and in age-matched control subjects, %CoQ-10 values were 12.9 +/- 10.3 (n = 28), 10.6 +/- 6.8 (n = 28), 18.9 +/- 11.1 (n = 20), and 6.4 +/- 3.3 (n = 16), respectively, showing a significant increase in oxidative stress in patient groups as compared to control subjects. There were no differences in total amounts of ubiquinone-10 and ubiquinol-10 among the four groups. We next measured %CoQ-10 in plasmas obtained from nine patients treated with percutaneous transluminal coronary angioplasty (PTCA). Plasmas were collected when hospitalized, and at the time (0, 4, 8, 12, 16, and 20 hr, and 1, 2, 3, 4, and 7 days) after the PTCA. %CoQ-10 values before and right after PTCA were 9.9 +/- 2.8 and 11.4 +/- 2.0, respectively, reached a maximum (20-45) at 1 or 2 days later, and decreased to 7.9 +/- 2.7 at 7 days after PTCA, indicating an increase in oxidative stress in patients during coronary reperfusion.

Topics: Adult; Aged; Aged, 80 and over; Angioplasty, Balloon, Coronary; Ascorbic Acid; beta Carotene; Bilirubin; Biomarkers; Carcinoma, Hepatocellular; Carotenoids; Female; Hepatitis; Humans; Liver Cirrhosis; Liver Neoplasms; Lycopene; Male; Middle Aged; Oxidative Stress; Reference Values; Ubiquinone; Uric Acid; Vitamin E

We have applied our method for the simultaneous detection of plasma ubiquinol-10 (reduced form) and ubiquinone-10 (oxidized form) (S. Yamashita and Y. Yamamoto, Anal. Biochem. 250, 66-73, 1997) to plasmas of normal subjects (n = 16) and patients with chronic active hepatitis (n = 28), liver cirrhosis (n = 16), and hepatocellular carcinoma (n = 20) to evaluate the pressure of oxidative stress in these patients. The average ubiquinone-10 percentages (+/- S.D.) in total ubiquinone-10 and ubiquinol-10 in the four groups were 6.4 +/- 3.3, 12.9 +/- 10.3, 10.6 +/- 6.8, and 18.9 +/- 11.1, respectively, indicating a significant increase in ubiquinone-10 percentage in patient groups in comparison to normal subjects. These results and a significant decrease in the plasma ascorbate level in patient groups indicate that oxidative stress is evident after the onset of hepatitis and the subsequent cirrhosis and liver cancer.

Topics: Adult; Aged; Aged, 80 and over; Antioxidants; Ascorbic Acid; beta Carotene; Biomarkers; Carcinoma, Hepatocellular; Carotenoids; Cholesterol; Cholesterol Esters; Female; Hepatitis, Chronic; Humans; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Lycopene; Male; Middle Aged; Oxidative Stress; Ubiquinone; Vitamin E

Oxidative stress is defined as a disturbance in the prooxidant-antioxidant balance in favor of the former and has been suggested to be a relevant factor in aging as well as in different pathological conditions, such as heart attack, diabetes, and cancer. Ubiquinol is very sensitive against oxygen radicals and gives ubiquinone as an oxidation product. Therefore, the ratio of ubiquinol to ubiquinone should be a good marker of oxidative stress because of its definition. A method for the simultaneous detection of ubiquinol-10 and ubiquinone-10 in human plasma is described. Heparinized human plasma was mixed with 5 volumes of methanol and 10 volumes of hexane. After vigorous shaking and centrifugation, the hexane phase (5 microliters) was injected immediately and directly on to reverse-phase HPLC equipped with an on-line reduction column and an electrochemical detector in order to avoid the oxidation of ubiquinol to ubiquinone. It was found that the ratio of ubiquinol-10 to ubiquinone-10 was about 95/5 in human plasma from healthy donors. A significant increase in the oxidized form (ubiquinone-10) content was observed in plasmas of patients with hepatitis, cirrhosis, and hepatoma when compared with normal subjects, suggesting increased oxidative stress in these patients.

Topics: Biomarkers; Carcinoma, Hepatocellular; Chromatography, High Pressure Liquid; Coenzymes; Electrochemistry; Hepatitis; Hexanes; Humans; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species; Solvents; Ubiquinone; Vitamin E

Ubiquinol-10 (CoQ10H2) is present in human low density lipoproteins (LDL) where it contributes significantly to the antioxidant defenses against radical-mediated oxidative damage. As CoQ10H2 becomes oxidized to ubiquinone-10 (CoQ10) during the earliest stages of in vitro oxidation of LDL, we investigated a possible cellular recycling of oxidized CoQ10H2, adding CoQ10 or its ambiphilic, short-chain analogue ubiquinone-1 (CoQ1), to cells that are exposed to LDL in vivo. Whole blood, isolated red blood cells and human hepatoma Hep G2 cells (used as a model of hepatocytes) rapidly and efficiently reduced added CoQ1 to ubiquinol-1 (CoQ1H2) detectable outside the cells. In whole blood the same steady-state level of CoQ1H2 was reached whether an equimolar amount of CoQ1 or CoQ1H2 was added. Red cell membranes also showed some reducing activity, whereas CoQ1 added to human blood plasma remained largely in its oxidized form. Cell- and membrane-mediated reduction of CoQ1 was enhanced by NADH, FAD, or human plasma. In comparison to this rapid reduction of extracellular CoQ1, formation of CoQ10H2 from CoQ10 incorporated into human LDL by red blood and Hep G2 cells was slow. Our results show that although human blood cells and Hep G2 cells are endowed with a highly reducing activity for CoQ1, the natural CoQ10 does not appear to represent an efficient substrate for this activity.

Topics: Adult; Blood Cells; Carcinoma, Hepatocellular; Humans; Kinetics; Lipoproteins, LDL; Liver; Oxidation-Reduction; Tumor Cells, Cultured; Ubiquinone