New analytical strategies applied to the determination of Coenzyme Q10 in biological matrix

Coenzyme Q10 deficiency in patients with hereditary hemochromatosis

AIM

Hereditary hemochromatosis (HH) is a group of inherited disorders that causes a slow and progressive iron deposition in diverse organs, particularly in the liver. Iron overload induces oxidative stress and tissue damage. Coenzyme Q10 (CoQ10) is a cofactor in the electron-transport chain of the mitochondria, but it is also a potent endogenous antioxidant. CoQ10 interest has recently grown since various studies show that CoQ10 supplementation may provide protective and safe benefits in mitochondrial diseases and oxidative stress disorders. In the present study we sought to determine CoQ10 plasma level in patients recently diagnosed with HH and to correlate it with biochemical, genetic, and histological features of the disease.

METHODS

Plasma levels of CoQ10, iron, ferritin, transferrin and vitamins (A, C and E), liver tests (transaminases, alkaline phosphatase and bilirubin), and histology, as well as three HFE gene mutations (H63D, S654C and C282Y), were assessed in thirty-eight patients (32 males, 6 females) newly diagnosed with HH without treatment and in twenty-five age-matched normolipidemic healthy subjects with no HFE gene mutations (22 males, 3 females) and without clinical or biochemical signs of iron overload or liver diseases.

RESULTS

Patients with HH showed a significant decrease in CoQ10 levels respect to control subjects (0.31 ± 0.03 µM vs 0.70 ± 0.06 µM, p < 0.001, respectively) independently of the genetic mutation, cirrhosis, transferrin saturation, ferritin level or markers of hepatic dysfunction. Although a decreasing trend in CoQ10 levels was observed in patients with elevated iron levels, no correlation was found between both parameters in patients with HH. Vitamins C and A levels showed no changes in HH patients. Vitamin E was significantly decreased in HH patients (21.1 ± 1.3 µM vs 29.9 ± 2.5 µM, p < 0.001, respectively), but no correlation was observed with CoQ10 levels.

CONCLUSION

The decrease in CoQ10 levels found in HH patients suggests that CoQ10 supplementation could be a safe intervention strategy complementary to the traditional therapy to ameliorate oxidative stress and further tissue damage induced by iron overload.

Neuroprotective effects of coenzyme Q10 in Parkinson's model via a novel Q10/miR-149-5p/MMPs pathway

Parkinson's disease (PD) is a complex neurodegenerative disease in which the understanding of the underlying molecular mechanisms can be constructive in the diagnosis and treatment. Matrix metalloproteinase (MMPs) elevation and damage to the blood-brain barrier (BBB) are critical mechanisms involved in the PD separation. Studies have revealed that changes in miR-149-5p and CoQ10 are associated with BBB damage, and CoQ10 can affect the levels of some miRs. Hence, in the present study, we aimed to evaluate CoQ10 and miR-149-5p mimic on miR-149-5p, MMPs and TH expression, and behavioral functions of the PD models. PD was induced by injection of 6-OHDA into the rats' Medial Forbrain Bundle (MFB). The behavioral tests, including the Rotation test, Rotarod test, and Open field test, have been directed two weeks after PD induction. Next, the MiR-149-5p mimic (miR-mimic) and CoQ10 have been administered to rats. The same behavioral tests have been evaluated two weeks after administration to investigate the effect of miR-149-5p mimic and CoQ10. The rats were followed extra four weeks, and the behavioral tests have performed again. Finally, the expression of MMPs and miR-149-5p genes was measured using RT-qPCR, and tyrosine hydroxylase (TH) was assessed through immunohistochemistry analysis. According to the obtained results, the level of miR-149-5p has decreased, followed by PD induction in rats. RT-qPCR analysis has represented upregulation and downregulation of miR-149-5p and MMP-2,9, respectively, after miR-mimic and CoQ10 treatment. The treated rats have also represented improved motor function and increased TH +  cells in the striatum according to the behavioral tests and immunohistochemistry assay. Taking together miR-149 and CoQ10 has shown to have an impressive potential to prevent damage to dopaminergic neurons caused by 6-OHDA injection through reducing MMP-2,9, increased TH expression, and improved motor function.

Coenzyme Q 10 supplementation: A potential therapeutic option for the treatment of intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy specific liver disease characterized by pruritus, elevated serum bile acids and abnormal liver function that may be associated with severe adverse pregnancy outcomes. We previously reported that plasma coenzyme Q10 (CoQ10) is decreased in women with ICP as it is its analogue coenzyme Q9 (CoQ9) in rats with ethinyl estradiol (EE)-induced cholestasis. The aim of the present study was to evaluate the possible therapeutic role of CoQ10 in experimental hepatocellular cholestasis and to compare it with ursodeoxycholic acid (UDCA) supplementation. Bile acids, CoQ9, CoQ10, transaminases, alkaline phosphatase, retinol, α-tocopherol, ascorbic acid, thiobarbituric acid reactive substances, carbonyls, glutathione, superoxide dismutase and catalase were assessed in plasma, liver and/or hepatic mitochondria in control and cholestatic rats supplemented with CoQ10 (250 mg/kg) administered alone or combined with UDCA (25 mg/kg). CoQ10 supplementation prevented bile flow decline (P < 0.05) and the increase in serum alkaline phosphatase and bile acids, particularly lithocholic acid (P < 0.05) in cholestatic rats. Furthermore, it also improved oxidative stress parameters in the liver, increased both CoQ10 and CoQ9 plasma levels and partially prevented the fall in α-tocopherol (P < 0.05). UDCA also prevented cholestasis, but it was less efficient than CoQ10 to improve the liver redox environment. Combined administration of CoQ10 and UDCA resulted in additive effects. In conclusion, present findings show that CoQ10 supplementation attenuated EE-induced cholestasis by promoting a favorable redox environment in the liver, and further suggest that it may represent an alternative therapeutic option for ICP.

Analytical Method Development for Coq10 Determination in Human Plasma Using HPLC-UV and HPLC/MS/MS

Background:

CoQ10 is a very important compound which is found in every tissue of our organism. It participates in the processes of cellular respiration and ATP production. Also, it acts as a strong antioxidant. In an organism, it is represented in two forms: oxidized (ubiquinone) and reduced (ubiquinol). Its low blood level may be a signal for a list of diseases.

Materials and Methods:

This study developed and compared two methods of CoQ10 determination in order to find the fastest and the most convenient one. The first one involved HPLC-UV with the wavelength of ubiquinone determination equivalent to 290 nm and 275 nm for ubiquinol, respectively. The second one was carried out on an HPLC/MS/MS system utilizing Electrospray Ionization (ESI) and triple quadrupole mass analyzer for quantification in MRM positive mode.

Results:

Two methods of ubiquinol and ubiquinone determination were developed and validated. HPLC-UV included sample preparation based on liquid-liquid extraction. The LLOQ was 0.50 µg/ml. HPLC-MS/MS method sample preparation was based on protein precipitation. The LLOQ was 0.10 µg/ml.

Conclusion:

During the investigation, a conclusion was drawn that the HPLC-UV method is too insensitive for simultaneous determination of ubiquinol and ubiquinone. Furthermore, ubiquinol is very unstable and during exogenous factors’ exposure, it rapidly turns into ubiquinone. While, the HPLCMS/ MS method turned out to be sensitive, selective, rapid as it provides an accurate determination of both forms of CoQ10 in spiked human plasma.

Attenuation of Oxidative Damage by Coenzyme Q10 Loaded Nanoemulsion Through Oral Route for the Management of Parkinson's Disease

Coenzyme Q₁₀ (CoQ₁₀) is a well-known antioxidant molecule which is used in the treatment of neurodegenerative disorders, but due to poor solubility it suffers with the drawback of low oral bioavailability. The aim of present study was to prepare and characterize CoQ₁₀ loaded nanoemulsion to improve the oral bioavailability. Prepared formulation was studied for droplet size, polydispersity index (PDI), percentage transmittance, refractive index, viscosity, zeta potential, surface morphology by transmission electron microscopy, and in vitro release study. Optimized formulation (A10) showed spherical droplets with mean diameter of 60.00 ± 15 nm, PDI of 0.121 ± 0.053, and zeta potential values of -24.40 ± 0.16 mV. Prepared nanoemulsion exhibited good transmittance (100.50% ± 0.86%), refractive index (1.41 ± 0.02), and viscosity (30.54 ± 2.86 cP). Various behavioral tests like forced swimming test, locomotor activity test, catalepsy, muscle coordination test, and akinesia test performed in haloperidol challenged rats and treated with CoQ₁₀ nanoemulsion significantly improved the behavioral activities in comparison to CoQ₁₀ suspension by reducing nigrostriatal dopamine depletion and thereby helping in the treatment of Parkinson's disease. Biochemical estimation data showed that CoQ₁₀ nanoemulsion was helpful in elevating the decreased content of glutathione and reducing the increased content of thiobarbituric acid reactive substances. Improved CoQ₁₀ release was obtained with nanoemulsions. Pharmacokinetic study results revealed that nanoemulsion exhibited 1.81 times enhancement in bioavailability in comparison to CoQ₁₀ suspension.

Relative bioavailability of coenzyme Q10 formulation for paediatric individualized therapy

OBJECTIVES

Conduct a preliminary comparison of the bioavailability between two formulations: commercial grade coenzyme Q10 (CoQ10) powder (solid formulation) and a new oil-in-water liquid emulsion and their effect on other antioxidants.

METHODS

Six healthy individuals participated in a randomized, crossover, open, consecutive design, with a 2-week washout period. Pharmacokinetic parameters were assessed after a single and multiple intakes of 250 mg CoQ10 given daily for 1 week.

KEY FINDINGS

The differences in the pharmacokinetic parameters of maximum plasma concentration, area under the curve between 0-360 and 0-4 h, elimination half-life were statistically significant with a relative bioavailability of 489% increase over solid CoQ10 formulation. A multiple dose supplementation increased plasma CoQ10 levels in both formulations, liquid emulsion performing better (2.4- vs 3.9-fold for solid and liquid formulation, respectively) without modifications on other antioxidants. Furthermore, the plasma CoQ10 at 7th day was statistically different between formulations (P < 0.05).

CONCLUSIONS

The results obtained showed that liquid emulsion improves the bioavailability of CoQ10 respect to solid form which not only facilitates the individualized administration for the child but in turn could increase the therapeutic efficacy, which should be confirmed by further studies.