Oxidative stress, endothelial function and coenzyme Q10

Six-month supplementation with high dose coenzyme Q10 improves liver steatosis, endothelial, vascular and myocardial function in patients with metabolic-dysfunction associated steatotic liver disease: a randomized double-blind, placebo-controlled trial

BACKROUND

Metabolic-dysfunction Associated Steatotic Liver Disease (MASLD) has been associated with increased cardiovascular risk. The aim of this Randomized Double-blind clinical Trial was to evaluate the effects of coenzyme-Q10 supplementation in patients with MASLD in terms of endothelial, vascular and myocardial function.

METHODS

Sixty patients with MASLD were randomized to receive daily 240 mg of coenzyme-Q10 or placebo. At baseline and at 6-months, the a)Perfused boundary region of sublingual vessels using the Sideview Darkfield imaging technique, b)pulse-wave-velocity, c)flow-mediated dilation of the brachial artery, d)left ventricular global longitudinal strain, e)coronary flow reserve of the left anterior descending coronary artery and f)controlled attenuation parameter for the quantification of liver steatosis were evaluated.

RESULTS

Six months post-treatment, patients under coenzyme-Q10 showed reduced Perfused boundary region (2.18 ± 0.23vs.2.29 ± 0.18 μm), pulse-wave-velocity (9.5 ± 2vs.10.2 ± 2.3 m/s), controlled attenuation parameter (280.9 ± 33.4vs.304.8 ± 37.4dB/m), and increased flow-mediated dilation (6.1 ± 3.8vs.4.3 ± 2.8%), global longitudinal strain (-19.6 ± 1.6vs.-18.8 ± 1.9%) and coronary flow reserve (3.1 ± 0.4vs.2.8 ± 0.4) compared to baseline (p < 0.05). The placebo group exhibited no improvement during the 6-month follow-up period (p > 0.05). In patients under coenzyme-Q10, the reduction in controlled attenuation parameter score was positively related to the reduction in Perfused boundary region and pulse wave velocity and reversely related to the increase in coronary flow reserve and flow-mediated dilation (p < 0.05 for all relations).

CONCLUSIONS

Six-month treatment with high-dose coenzyme-Q10 reduces liver steatosis and improves endothelial, vascular and left ventricle myocardial function in patients with MASLD, demonstrating significant improvements in micro- and macro-vasculature function.

TRIAL REGISTRATION

NCT05941910.

Improving mitochondrial function in preclinical models of heart failure: therapeutic targets for future clinical therapies?

INTRODUCTION

Heart failure is a complex clinical syndrome resulting from the unsuccessful compensation of symptoms of myocardial damage. Mitochondrial dysfunction is a process that occurs because of an attempt to adapt to the disruption of metabolic and energetic pathways occurring in the myocardium. This, in turn, leads to further dysfunction in cardiomyocyte processes. Currently, many therapeutic strategies have been implemented to improve mitochondrial function, but their effectiveness varies widely.

AREAS COVERED

This review focuses on new models of therapeutic strategies targeting mitochondrial function in the treatment of heart failure.

EXPERT OPINION

Therapeutic strategies targeting mitochondria appear to be a valuable option for treating heart failure. Currently, the greatest challenge is to develop new research models that could restore the disrupted metabolic processes in mitochondria as comprehensively as possible. Only the development of therapies that focus on improving as many dysregulated mitochondrial processes as possible in patients with heart failure will be able to bring the expected clinical improvement, along with inhibition of disease progression. Combined strategies involving the reduction of the effects of oxidative stress and mitochondrial dysfunction, appear to be a promising possibility for developing new therapies for a complex and multifactorial disease such as heart failure.

Coenzyme Q10 prevented Trypanosoma brucei rhodesiense-mediated breach of the blood brain barrier, inflammation and organ damage in late stage of Human African Trypanosomiasis

During the late stage of Human African Trypanosomiasis (HAT), there is severe cytokine-driven inflammation, oxidative stress and organ damage. Controlling inflammation and oxidative damage presents unique therapeutic opportunities to improve treatment outcome. The current study sought to determine the putative impact of Coenzyme-Q10 (Co-Q10), a potent antioxidant and anti-inflammatory, on adverse inflammatory and oxidative events during Trypanosoma brucei rhodesiense (T.b.r) infection. Group one constituted the control; the second group was infected with T.b.r; the third group was orally administered with 200 mg/kg Co-Q10 for two weeks; thereafter, Co-Q10 administration continued after infection with T.b.r. Co-Q10 improved the survival rate of infected mice and prevented full blown parasite driven splenomegaly and hepatomegaly. Co-Q10 prevented characteristic T.b.r-driven breach of the blood brain barrier and improved neurological integrity among T.b.r infected mice. Co-Q10 protected from T.b.r-induced microcytic hypochromic anaemia and thrombocytopenia. T.b.r-induced oxidative stress in the vital organs was assuaged following exposure to Co-Q10. Co-Q10 blocked T.b.r-induced derangement of high density lipoprotein and triglyceride levels. Co-Q10 significantly abrogated T.b.r-driven elevation of serum TNF-α and IFN-γ levels. Moreover, T.b.r-induced kidney and liver damage was assuaged by Co-Q10 administration. Co-Q10 administration downregulated T.b.r-induced elevation of uric acid and C-reactive protein. Likewise, T.b.r infected mice receiving Co-Q10 exhibited normal brain architecture. In conclusion, treatment with Co-Q10 may be useful in protecting against T.b.r-mediated organ injury, lethal inflammation and oxidative stress commonly present in severe late stage HAT; and presents unique opportunities for an adjunct therapy for late stage HAT.

Molecular mechanisms underlying the renal protective effects of coenzyme Q10 in acute kidney injury

Coenzyme Q10 (CoQ10), an endogenous antioxidant, has been reported frequently to exert an outstanding protective effect on multiple organ injury, including acute kidney injury (AKI). In this study, we aim to summarize all the current evidence of the protective action of CoQ10 against AKI as there are presently no relevant reviews in the literature. After a systematic search, 20 eligible studies, either clinical trials or experimental studies, were included and further reviewed. CoQ10 treatment exhibited a potent renal protective effect on various types of AKI, such as AKI induced by drugs (e.g., ochratoxin A, cisplatin, gentamicin, L-NAME, and nonsteroidal anti-inflammatory drug), extracorporeal shock wave lithotripsy (ESWL), sepsis, contrast media, and ischemia–reperfusion injury. The renal protective role of CoQ10 against AKI might be mediated by the antiperoxidative, anti-apoptotic, and anti-inflammatory potential of CoQ10. The molecular mechanisms for the protective effects of CoQ10 might be attributed to the regulation of multiple essential genes (e.g., caspase-3, p53, and PON1) and signaling cascades (e.g., Nrf2/HO-1 pathway). This review highlights that CoQ10 may be a potential strategy in the treatment of AKI.

Influence of Systemic Administration of Coq10 Nanoparticles on Ischemia-Reperfusion Injury on Ovaries in Rat

Using a rat ovary model, effects of COQ10 nanoparticles (NCOQ10) were studied on ischemia-reperfusion injury. In the present experimental study, following randomization of thirty healthy female Wistar rats ∼250 g, the animals were subjected to five experimental groups (n = 6): group SHAM : only laparotomy was performed, group IS: only a 3-hour ischemia was performed, group IS/REP: the procedure included a 3-hour ischemia followed by a 3-hour reperfusion, and 50 µL soybean oil (solvent of NCOQ10) was administered 30 min before cessation of reperfusion, group IS/NCOQ10: the procedure included a 3-hour ischemia only and 50 µL (0.3 mmol/lit/IP) of NCOQ10 30 min before cessation of ischemia, and group IS/REP/NCOQ10: the procedure included a 3-hour ischemia, a 3-hour reperfusion, and 20 µL (0.3 mmol/lit) of NCOQ10 30 min before cessation of ischemia. Significantly amended development of ischemia/reperfusion tissue injury was observed in animals treated with NCOQ10 compared to those of other groups (P=0.001). Mean values of biochemical indices were significantly higher than those observed for other groups (P=0.001). Significantly lower values of MDA were observed in IS/REP/NCOQ10 animals compared to those of other groups (P=0.001).Where ovarian tissue is exposed to ischemia, intraperitoneal administration of NCOQ10 could bear clinical benefits in diminishing ischemia-reperfusion injury.

How Robust is the Evidence for a Role of Oxidative Stress in Autism Spectrum Disorders and Intellectual Disabilities?

Growing interest in the pathogenesis of autism spectrum disorders (ASDs) and other intellectual and developmental disabilities (IDD) has led to emerging evidence implicating a role for oxidative stress. However, understanding the strength of this association is made challenging by the use of a variety of purported biomarkers of oxidative stress, many of which have either uncertain specificity or flawed methods of analysis. This review aims to address this issue, which is widespread in the ASD and IDD literature, by providing readers with information concerning the strengths and limitations of the choice and analysis of biomarkers of oxidative stress. We highlight that biomarkers and assays should be specific, sensitive, reproducible, precise, robust, and chosen with careful consideration. Future studies should be sufficiently powered and address sample collection, processing, and storage which are, additionally, poorly considered, sources of bad practice, and potential errors. Only with these issues considered, will the data lead to conclusions as to the precise role of oxidative stress in ASDs and IDD.

Coenzyme Q10 and Cardiovascular Diseases

Coenzyme Q₁₀ (CoQ₁₀), which plays a key role in the electron transport chain by providing an adequate, efficient supply of energy, has another relevant function as an antioxidant, acting in mitochondria, other cell compartments, and plasma lipoproteins. CoQ₁₀ deficiency is present in chronic and age-related diseases. In particular, in cardiovascular diseases (CVDs), there is a reduced bioavailability of CoQ₁₀ since statins, one of the most common lipid-lowering drugs, inhibit the common pathway shared by CoQ₁₀ endogenous biosynthesis and cholesterol biosynthesis. Different clinical trials have analyzed the effect of CoQ₁₀ supplementation as a treatment to ameliorate these deficiencies in the context of CVDs. In this review, we focus on recent advances in CoQ₁₀ supplementation and the clinical implications in the reduction of cardiovascular risk factors (such as lipid and lipoprotein levels, blood pressure, or endothelial function) as well as in a therapeutic approach for the reduction of the clinical complications of CVD.

Coenzyme Q10 for heart failure

BACKGROUND

Coenzyme Q10, or ubiquinone, is a non-prescription nutritional supplement. It is a fat-soluble molecule that acts as an electron carrier in mitochondria, and as a coenzyme for mitochondrial enzymes. Coenzyme Q10 deficiency may be associated with a multitude of diseases, including heart failure. The severity of heart failure correlates with the severity of coenzyme Q10 deficiency. Emerging data suggest that the harmful effects of reactive oxygen species are increased in people with heart failure, and coenzyme Q10 may help to reduce these toxic effects because of its antioxidant activity. Coenzyme Q10 may also have a role in stabilising myocardial calcium-dependent ion channels, and in preventing the consumption of metabolites essential for adenosine-5'-triphosphate (ATP) synthesis. Coenzyme Q10, although not a primary recommended treatment, could be beneficial to people with heart failure. Several randomised controlled trials have compared coenzyme Q10 to other therapeutic modalities, but no systematic review of existing randomised trials was conducted prior to the original version of this Cochrane Review, in 2014.

OBJECTIVES

To review the safety and efficacy of coenzyme Q10 in heart failure.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Web of Science, CINAHL Plus, and AMED on 16 October 2020; ClinicalTrials.gov on 16 July 2020, and the ISRCTN Registry on 11 November 2019. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials of either parallel or cross-over design that assessed the beneficial and harmful effects of coenzyme Q10 in people with heart failure. When we identified cross-over studies, we considered data only from the first phase.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods, assessed study risk of bias using the Cochrane 'Risk of bias' tool, and GRADE methods to assess the quality of the evidence. For dichotomous data, we calculated the risk ratio (RR); for continuous data, the mean difference (MD), both with 95% confidence intervals (CI). Where appropriate data were available, we conducted meta-analysis. When meta-analysis was not possible, we wrote a narrative synthesis. We provided a PRISMA flow chart to show the flow of study selection.

MAIN RESULTS

We included eleven studies, with 1573 participants, comparing coenzyme Q10 to placebo or conventional therapy (control). In the majority of the studies, sample size was relatively small. There were important differences among studies in daily coenzyme Q10 dose, follow-up period, and the measures of treatment effect. All studies had unclear, or high risk of bias, or both, in one or more bias domains. We were only able to conduct meta-analysis for some of the outcomes. None of the included trials considered quality of life, measured on a validated scale, exercise variables (exercise haemodynamics), or cost-effectiveness. Coenzyme Q10 probably reduces the risk of all-cause mortality more than control (RR 0.58, 95% CI 0.35 to 0.95; 1 study, 420 participants; number needed to treat for an additional beneficial outcome (NNTB) 13.3; moderate-quality evidence). There was low-quality evidence of inconclusive results between the coenzyme Q10 and control groups for the risk of myocardial infarction (RR 1.62, 95% CI 0.27 to 9.59; 1 study, 420 participants), and stroke (RR 0.18, 95% CI 0.02 to 1.48; 1 study, 420 participants). Coenzyme Q10 probably reduces hospitalisation related to heart failure (RR 0.62, 95% CI 0.49 to 0.78; 2 studies, 1061 participants; NNTB 9.7; moderate-quality evidence). Very low-quality evidence suggests that coenzyme Q10 may improve the left ventricular ejection fraction (MD 1.77, 95% CI 0.09 to 3.44; 7 studies, 650 participants), but the results are inconclusive for exercise capacity (MD 48.23, 95% CI -24.75 to 121.20; 3 studies, 91 participants); and the risk of developing adverse events (RR 0.70, 95% CI 0.45 to 1.10; 2 studies, 568 participants). We downgraded the quality of the evidence mainly due to high risk of bias and imprecision.

AUTHORS' CONCLUSIONS

The included studies provide moderate-quality evidence that coenzyme Q10 probably reduces all-cause mortality and hospitalisation for heart failure. There is low-quality evidence of inconclusive results as to whether coenzyme Q10 has an effect on the risk of myocardial infarction, or stroke. Because of very low-quality evidence, it is very uncertain whether coenzyme Q10 has an effect on either left ventricular ejection fraction or exercise capacity. There is low-quality evidence that coenzyme Q10 may increase the risk of adverse effects, or have little to no difference. There is currently no convincing evidence to support or refute the use of coenzyme Q10 for heart failure. Future trials are needed to confirm our findings.

Coenzyme Q10 Supplementation for the Reduction of Oxidative Stress: Clinical Implications in the Treatment of Chronic Diseases

Apart from its main function in the mitochondria as a key element in electron transport, Coenzyme Q₁₀ (CoQ₁₀) has been described as having multiple functions, such as oxidant action in the generation of signals and the control of membrane structure and phospholipid and cellular redox status. Among these, the most relevant and most frequently studied function is the potent antioxidant capability of its coexistent redox forms. Different clinical trials have investigated the effect of CoQ₁₀ supplementation and its ability to reduce oxidative stress. In this review, we focused on recent advances in CoQ₁₀ supplementation, its role as an antioxidant, and the clinical implications that this entails in the treatment of chronic diseases, in particular cardiovascular diseases, kidney disease, chronic obstructive pulmonary disease, non-alcoholic fatty liver disease, and neurodegenerative diseases. As an antioxidant, CoQ₁₀ has proved to be of potential use as a treatment in diseases in which oxidative stress is a hallmark, and beneficial effects of CoQ₁₀ have been reported in the treatment of chronic diseases. However, it is crucial to reach a consensus on the optimal dose and the use of different formulations, which vary from ubiquinol or ubiquinone Ubisol-Q₁₀ or Qter^®, to new analogues such as MitoQ, before we can draw a clear conclusion about its clinical use. In addition, a major effort must be made to demonstrate its beneficial effects in clinical trials, with a view to making the implementation of CoQ₁₀ possible in clinical practice.

Coenzyme Q10 nullified khat-induced hepatotoxicity, nephrotoxicity and inflammation in a mouse model

Ethnopharmacological relevance

The consumption of khat (Catha Edulis, Forsk) is on the rise despite the much publicized associated deleterious health effects. How chemicals present in khat, affect various physiological and biochemical processes requires further scrutiny. A clear understanding of these processes will provide an avenue for countering khat-driven negative effects using appropriate pharmacological and/or nutritional interventions.

Aim of the study

The current study investigated the effect of khat on vital physiological and biochemical processes such as oxidative stress, inflammation and immune responses and the role of Coenzyme-Q₁₀ (CoQ₁₀), a potent antioxidant and anti-inflammatory, in modulating any negative effects due to khat exposure.

Methodology

Three (3) weeks old forty (40) Swiss albino mice were randomly assigned into four treatment groups (n = 10). The first group was the control that was not administered with khat or CoQ₁₀. The second group received 200 mg/kg body weight (b/w) of CoQ₁₀, while the third group received 1500 mg/kg b/w of khat extract and finally the forth group was co-treated with 200 mg/kg b/w of CoQ₁₀ and 1500 mg/kg b/w of khat extract. The experiment was conducted for 90 days after which samples were collected for physiological and biochemical analyses.

Results

The effects of khat and CoQ₁₀ on the weights of brain, liver, kidney and spleen was determined. Administration of khat decreased the levels of RBCs and its subtypes (MCV, MCH, RDW-SD and RDW-CV), a clear indicator of khat-induced normochromic microcytic anemia. White blood cells (lymphocytes, monocytes, neutrophils and eosinophil) which are vital in responding to infections were markedly elevated by khat. Moreover, these results provide evidence for khat-induced liver and kidney injury as shown by increased biomarkers; AST, ALT, GGT and creatinine respectively. Standard histopathological analysis confirmed this finding for khat-driven liver and kidney injury. Further studies showed evidence for khat-induced inflammation and oxidative stress as depicted by increased levels of the pro-inflammatory cytokine TNF-alpha and elevation of GSH in the brain, liver and spleen. Remarkably, this is the first study to demonstrate the potential of CoQ₁₀ in ameliorating khat-induced negative effects as outlined. CoQ₁₀ supplementation restored the khat-induced reduction in RBC subtypes, and was protective against liver and kidney injury as shown by the appropriate biomarkers and standard histopathology analysis. The other significant finding was the CoQ₁₀-driven normalization of GSH and TNF-α levels, indicating a protective effect from khat-driven oxidative stress and inflammation respectively.

Conclusion

From this study, we conclude that CoQ₁₀ may be useful in nullifying khat-driven deleterious events among chronic khat users.

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.

Coenzyme Q10 mitigates ionizing radiation-induced testicular damage in rats through inhibition of oxidative stress and mitochondria-mediated apoptotic cell death

Radiotherapy is a common treatment modality for cancer patients; however, its use is limited by decreasing the probability of fertility in male cancer survivors. Therefore, this study aimed to define the capability of coenzyme Q10 (CoQ10), a potent stimulator of mitochondrial function, in attenuating ionizing radiation (IR)-induced spermatogenesis impairments. Male Sprague Dawley rats were exposed to a single dose of ϒ-rays (10 Gy) and/or treated with CoQ10 (10 mg/kg, orally, for 2 consecutive weeks). IR mediated irregular seminiferous tubules, which were emerged with typical morphological characteristics of apoptosis, and nuclear condensation, while CoQ10 significantly preserved the testicular structure and maintained spermatogenesis, which was displayed by higher levels of serum estradiol and testosterone. CoQ10 remarkably augmented sperm count, motility, and viability while diminished the rate of sperm-defects relatively to their counterparts after IR exposure. CoQ10 modulations in reproductive parameters were underpinned by attenuating IR-induced oxidative stress as evidenced by decreasing lipid peroxidation and increasing the antioxidant enzymes glutathione peroxidase and glutathione-s-transferase activities, and glutathione level. Supporting the involvement of CoQ10 in the anti-apoptotic response, the reduced mRNA expression levels of p53, Puma, and Bax accompanied by the increased Bcl-2 mRNA expression were observed. Subsequently, CoQ10 ameliorated the mitochondria dependent apoptotic pathway through diminishing Bax/Bcl-2 ratio, caspase-3 protein expression, and DNA fragmentation in testes of irradiated rats. Taken together, our findings showed that CoQ10 conserved against IR-induced steroidogenesis disruption through subsiding mitochondria-mediated oxidative stress injury in germinal cells.

Utilization of Complementary and Alternative Therapies in Youth with Developmental Disabilities

Oxidative stress is understood to be involved in the ontology and maintenance of different developmental disabilities. Some complementary and alternative medicine (CAM) therapies have been proposed to modify this relationship by affecting oxidative stress pathways. However, it is unclear which of these CAM therapies are used among children with different developmental disabilities. This study examines the use of these therapies among 10,218 children between the ages of 4 and 17 using the 2012 Child Complementary and Alternative Medicine (CAM) Supplement of the National Health Interview Survey (NHIS) to highlight a potential avenue for intervention and prevention efforts. The results suggest that children with developmental disabilities are more likely to utilize particular CAM therapies that may alter oxidative stress pathways. Future work is needed to assess the potential moderating effect of these CAM therapies and oxidative stress levels among children with different developmental disabilities.

Intracellular cholesterol accumulation and coenzyme Q10 deficiency in Familial Hypercholesterolemia

Familial Hypercholesterolemia (FH) is an autosomal co-dominant genetic disorder characterized by elevated low-density lipoprotein (LDL) cholesterol levels and increased risk for premature cardiovascular disease. Here, we examined FH pathophysiology in skin fibroblasts derived from FH patients harboring heterozygous mutations in the LDL-receptor. Fibroblasts from FH patients showed a reduced LDL-uptake associated with increased intracellular cholesterol levels and coenzyme Q₁₀ (CoQ₁₀) deficiency, suggesting dysregulation of the mevalonate pathway. Secondary CoQ₁₀ deficiency was associated with mitochondrial depolarization and mitophagy activation in FH fibroblasts. Persistent mitophagy altered autophagy flux and induced inflammasome activation accompanied by increased production of cytokines by mutant cells. All the pathological alterations in FH fibroblasts were also reproduced in a human endothelial cell line by LDL-receptor gene silencing. Both increased intracellular cholesterol and mitochondrial dysfunction in FH fibroblasts were partially restored by CoQ₁₀ supplementation. Dysregulated mevalonate pathway in FH, including increased expression of cholesterogenic enzymes and decreased expression of CoQ₁₀ biosynthetic enzymes, was also corrected by CoQ₁₀ treatment. Reduced CoQ₁₀ content and mitochondrial dysfunction may play an important role in the pathophysiology of early atherosclerosis in FH. The diagnosis of CoQ₁₀ deficiency and mitochondrial impairment in FH patients may also be important to establish early treatment with CoQ₁₀.

Potential Cardiovascular and Renal Protective Effects of Vitamin D and Coenzyme Q10 in l-NAME-Induced Hypertensive Rats

BACKGROUND

Hypertension is one of the primary modifiable risk factors for cardiovascular disease. Adequate vitamin D (vit D) levels have been shown to reduce vascular smooth muscle contraction and to increase arterial compliance, which may be beneficial in hypertension. Further, coenzyme Q10 (COQ10) through its action to lower oxidative stress has been reported to have beneficial effects on hypertension and heart failure. This study examined the possible cardiac and renal protective effects of vit D and COQ10 both separately and in combination with an angiotensin II receptor blocker, valsartan (vals) in l-NAME hypertensive rats.

MATERIALS AND METHODS

Hypertension was induced in rats by l-NAME administration. Following induction of hypertension, the rats were assigned into the following 6 subgroups: an l-NAME alone group and treated groups receiving the following drugs intraperitoneally for 6 weeks; vals, vit D, COQ10 and combination of vals with either vit D or COQ10. A group of normotensive rats were used as negative controls. At the end of the treatment period, blood pressure, serum creatinine, blood urea nitrogen, lipids and serum, cardiac and renal parameters of oxidative stress were measured.

RESULTS

Compared to the l-NAME only group, all treatments lowered systolic, diastolic, mean arterial pressure, total cholesterol, low-density lipoprotein cholesterol, and creatinine levels as well as TNF-α and malondialdehyde. Further, the agents increased serum, cardiac and renal total antioxidant capacity. Interestingly, the combination of agents had further effects on all the parameters compared to treatment with each single agent.

CONCLUSIONS

The study suggests that the additive protective effects of vit D and COQ10 when used alone or concurrent with vals treatment in hypertensive rats may be due to their effects as antioxidants, anticytokines and blood pressure conservers.

Effects of coenzyme q10 supplementation on serum lipoproteins, plasma fibrinogen, and blood pressure in patients with hyperlipidemia and myocardial infarction

BACKGROUND

Low plasma concentrations of coenzyme Q10 (CoQ10) have been associated with concentration of lipoproteins and other factors contributing to coronary heart diseases.

OBJECTIVES

The present investigation aimed to improve the blood pressure and serum lipoproteins concentration in patients with myocardial infarction (MI) by CoQ10 supplementation.

PATIENTS AND METHODS

In this randomized double-blinded controlled clinical trial, 52 Iranian patients with hyperlipidemia and MI were recruited to examine the effect of CoQ10 on serum total cholesterol (TC), LDL-C, HDL-C, triglyceride (TG), LDL-C/HDL-C ratio, TC/HDL-C ratio, fibrinogen, systolic blood pressure (SBP) and diastolic blood pressure (DBP). Individuals were randomly allocated to two groups for receiving either 200 mg/d of CoQ10 or placebo for 12 weeks.

RESULTS

There were not significant differences in serum LDL-C (2.70 ± 0.31 vs. 2.70 ± 0.35 mmol/L), TC (4.47 ± 0.33 vs. 4.93 ± 0.57 mmol/L), TG (2.48 ± 0.12 vs. 2.25 ± 0.69 mmol/L), and fibrinogen (2.08 ± 0.99 vs. 38.7 ± 0.64 mg/dL) between CoQ10 and placebo groups. After 12 weeks, a significant enhancement in serum HDL-C (1.44 ± 0.18 vs. 1.14 ± 0.18 mmol/L) level was observed between groups after the supplementation (P < 0.001). A significant reduction of TC, LDL-C, and fibrinogen and a significant increase in HDL-C concentration was observed in CoQ10 group after intervention (P < 0.001). Our assessment demonstrated statistically significant differences between the two groups in SBP and DBP after intervention (P < 0.001). ANCOVA also revealed significant differences in the ratio of LDL-C/HDL-C and TC/HDL-C between the two groups (1.89 ± 0.42 vs. 2.39 ± 0.38, P = 0.002; and 3.2 ± 0.5 vs. 4.24 ± 0.66, P = 0.01, respectively). A significant reduction of LDL-C/HDL-C and TC/HDL-C was observed in CoQ10 group (P < 0.001).

CONCLUSIONS

Twelve-week supplementation with CoQ10 in patients with hyperlipidemia and MI can improve blood pressure, serum HDL-C as well as LDL-C/HDL-C and TC/HDL-C ratios; therefore, it might decrease the risk of frequent MI.

Coenzyme Q10 for heart failure

BACKGROUND

Coenzyme Q10, or ubiquinone, is a non-prescription nutritional supplement. It is a fat-soluble molecule that acts as an electron carrier in mitochondria and as a coenzyme for mitochondrial enzymes. Coenzyme Q10 deficiency may be associated with a multitude of diseases including heart failure. The severity of heart failure correlates with the severity of coenzyme Q10 deficiency. Emerging data suggest that the harmful effects of reactive oxygen species are increased in patients with heart failure and coenzyme Q10 may help to reduce these toxic effects because of its antioxidant activity. Coenzyme Q10 may also have a role in stabilising myocardial calcium-dependent ion channels and preventing the consumption of metabolites essential for adenosine-5'-triphosphate (ATP) synthesis. Coenzyme Q10, although not a primary recommended treatment, could be beneficial to patients with heart failure. Several randomised controlled trials have compared coenzyme Q10 to other therapeutic modalities, but no systematic review of existing randomised trials has been conducted.

OBJECTIVES

To review the safety and efficacy of coenzyme Q10 in heart failure.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 12); MEDLINE OVID (1950 to January Week 3 2013) and EMBASE OVID (1980 to 2013 Week 03) on 24 January 2013; Web of Science with Conference Proceedings (1970 to January 2013) and CINAHL Plus (1981 to January 2013) on 25 January 2013; and AMED (Allied and Complementary Medicine) (1985 to January 2013) on 28 January 2013. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials of either parallel or cross-over design that assessed the beneficial and harmful effects of coenzyme Q10 in patients with heart failure. When cross-over studies were identified, we considered data only from the first phase.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the included studies onto a pre-designed data extraction form. We then entered the data into Review Manager 5.2 for analysis. We assessed study risk of bias using the Cochrane 'Risk of bias' tool. For dichotomous data, we calculated the risk ratio and for continuous data the mean difference (MD). Where appropriate data were available, we performed meta-analysis. For this review we prioritised data from pooled analyses only. Where meta-analysis was not possible, we wrote a narrative synthesis. We provided a QUOROM flow chart to show the flow of papers.

MAIN RESULTS

We included seven studies with 914 participants comparing conenzyme Q10 versus placebo. There were no data on clinical events from published randomised trials. The included studies had small sample sizes. Meta-analysis was only possible for a few physiological measures and there was substantial heterogeneity.Only one study reported on total mortality, major cardiovascular events and hospitalisation. Five trials reported on the New York Heart Association (NYHA) classification of clinical status, but it was impossible to pool data due to heterogeneity. None of the included trials considered quality of life, exercise variables, adverse events or cost-effectiveness as outcome measures. Pooled analysis suggests that the use of coenzyme Q10 has no clear effect on left ventricular ejection fraction (MD -2.26; 95% confidence interval (CI) -15.49 to 10.97, n = 60) or exercise capacity (MD 12.79; 95% CI -140.12 to 165.70, n = 85). Pooled data did indicate that supplementation increased blood levels of coenzyme Q10 (MD 1.46; 95% CI 1.19 to 1.72, n = 112). However, there are only a small number of small studies with a risk of bias, so these results should be interpreted with caution.

AUTHORS' CONCLUSIONS

No conclusions can be drawn on the benefits or harms of coenzyme Q10 in heart failure at this time as trials published to date lack information on clinically relevant endpoints. Furthermore, the existing data are derived from small, heterogeneous trials that concentrate on physiological measures: their results are inconclusive. Until further evidence emerges to support the use of coenzyme Q10 in heart failure, there might be a need to re-evaluate whether further trials testing coenzyme Q10 in heart failure are desirable.

Anti-inflammatory effect of ubiquinol-10 on young and senescent endothelial cells via miR-146a modulation

Clinical evidence demonstrates that ubiquinol-10, the reduced active form of coenzyme Q10 (CoQ10H₂), improves endothelial function through its antioxidant and probably its anti-inflammatory properties. We previously reported that a biomarker combination including miR-146a, its target protein IL-1 receptor-associated kinase (IRAK-1), and released interleukin (IL)-6, here collectively designated as MIRAKIL, indicates senescence-associated secretory phenotype (SASP) acquisition by primary human umbilical vein endothelial cells (HUVECs). We explore the ability of short- and long-term CoQ10H₂ supplementation to affect MIRAKIL in HUVECs, used as a model of vascular aging, during replicative senescence in the absence/presence of lipopolysaccharide (LPS), a proinflammatory stimulus. Senescent HUVECs had the same ability as young cells to internalize CoQ10 and exhibit an improved oxidative status. LPS-induced NF-κB activation diminished after CoQ10H₂ pretreatment in both young and senescent cells. However, short-term CoQ10H₂ supplementation attenuated LPS-induced MIRAKIL changes in young cells; in senescent cells CoQ10H₂ supplementation significantly attenuated LPS-induced miR-146a and IRAK-1 modulation but failed to curb IL-6 release. Similar results were obtained with long-term CoQ10H₂ incubation. These findings provide new insights into the molecular mechanisms by which CoQ10H₂ stems endothelial cell inflammatory responses and delays SASP acquisition. These phenomena may play a role in preventing the endothelial dysfunction associated with major age-related diseases.

Prophylactic and Antinociceptive Effects of Coenzyme Q10 on Diabetic Neuropathic Pain in a Mouse Model of Type 1 Diabetes

Background:

Oxidative stress is a key factor implicated in the development of diabetic neuropathy. This study evaluates the prophylactic and antinociceptive effects of the antioxidant coenzyme Q10 (CoQ10) on diabetes-induced neuropathic pain in a diabetic mouse model.

Methods:

Total 56 mice with type 1 diabetes induced by streptozotocin were used, 20 normal mice were used as control. Mechanical and thermal nociceptive behavioral assays were applied to evaluate diabetic neuropathic pain. Tissue lipid peroxidation, immunohistochemistry, reverse transcription, and polymerase chain reaction were used to evaluate the molecular mechanisms of CoQ10. Data are presented as mean ± SEM.

Results:

CoQ10 administration was associated with reduced loss of body weight compared with nontreated diabetic mice, without affecting blood glucose levels. Low dose and long-term administration of CoQ10 prevented the development of neuropathic pain. Treatment with CoQ10 produced a significant dose-dependent inhibition of mechanical allodynia and thermal hyperalgesia in diabetic mice. Dorsal root ganglia, sciatic nerve, and spinal cord tissues from diabetic mice demonstrated increased lipid peroxidation that was reduced by CoQ10 treatment. CoQ10 administration was also noted to reduce the proinflammatory factors in the peripheral and central nervous system.

Conclusions:

The results of this study support the hypothesis that hyperglycemia induced neuronal oxidative damage and reactive inflammation may be pathogenic in diabetic neuropathic pain. CoQ10 may be protective by inhibiting oxidative stress and reducing inflammation by down-regulating proinflammatory factors. These results suggest that CoQ10 administration may represent a low-risk, high-reward strategy for preventing or treating diabetic neuropathy.

Effect of coenzyme Q₁₀ supplementation on heart failure: a meta-analysis

BACKGROUND

Coenzyme Q₁₀ (CoQ₁₀; also called ubiquinone) is an antioxidant that has been postulated to improve functional status in congestive heart failure (CHF). Several randomized controlled trials have examined the effects of CoQ₁₀ on CHF with inconclusive results.

OBJECTIVE

The objective of this meta-analysis was to evaluate the impact of CoQ₁₀ supplementation on the ejection fraction (EF) and New York Heart Association (NYHA) functional classification in patients with CHF.

DESIGN

A systematic review of the literature was conducted by using databases including MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and manual examination of references from selected studies. Studies included were randomized controlled trials of CoQ₁₀ supplementation that reported the EF or NYHA functional class as a primary outcome. Information on participant characteristics, trial design and duration, treatment, dose, control, EF, and NYHA classification were extracted by using a standardized protocol.

RESULTS

Supplementation with CoQ₁₀ resulted in a pooled mean net change of 3.67% (95% CI: 1.60%, 5.74%) in the EF and -0.30 (95% CI: -0.66, 0.06) in the NYHA functional class. Subgroup analyses showed significant improvement in EF for crossover trials, trials with treatment duration ≤12 wk in length, studies published before 1994, and studies with a dose ≤100 mg CoQ₁₀/d and in patients with less severe CHF. These subgroup analyses should be interpreted cautiously because of the small number of studies and patients included in each subgroup.

CONCLUSIONS

Pooled analyses of available randomized controlled trials suggest that CoQ₁₀ may improve the EF in patients with CHF. Additional well-designed studies that include more diverse populations are needed.

Radiation protection following nuclear power accidents: a survey of putative mechanisms involved in the radioprotective actions of taurine during and after radiation exposure

There are several animal experiments showing that high doses of ionizing radiation lead to strongly enhanced leakage of taurine from damaged cells into the extracellular fluid, followed by enhanced urinary excretion. This radiation-induced taurine depletion can itself have various harmful effects (as will also be the case when taurine depletion is due to other causes, such as alcohol abuse or cancer therapy with cytotoxic drugs), but taurine supplementation has been shown to have radioprotective effects apparently going beyond what might be expected just as a consequence of correcting the harmful consequences of taurine deficiency per se. The mechanisms accounting for the radioprotective effects of taurine are, however, very incompletely understood. In this article an attempt is made to survey various mechanisms that potentially might be involved as parts of the explanation for the overall beneficial effect of high levels of taurine that has been found in experiments with animals or isolated cells exposed to high doses of ionizing radiation. It is proposed that taurine may have radioprotective effects by a combination of several mechanisms: (1) during the exposure to ionizing radiation by functioning as an antioxidant, but perhaps more because it counteracts the prooxidant catalytic effect of iron rather than functioning as an important scavenger of harmful molecules itself, (2) after the ionizing radiation exposure by helping to reduce the intensity of the post-traumatic inflammatory response, and thus reducing the extent of tissue damage that develops because of severe inflammation rather than as a direct effect of the ionizing radiation per se, (3) by functioning as a growth factor helping to enhance the growth rate of leukocytes and leukocyte progenitor cells and perhaps also of other rapidly proliferating cell types, such as enterocyte progenitor cells, which may be important for immunological recovery and perhaps also for rapid repair of various damaged tissues, especially in the intestines, and (4) by functioning as an antifibrogenic agent. A detailed discussion is given of possible mechanisms involved both in the antioxidant effects of taurine, in its anti-inflammatory effects and in its role as a growth factor for leukocytes and nerve cells, which might be closely related to its role as an osmolyte important for cellular volume regulation because of the close connection between cell volume regulation and the regulation of protein synthesis as well as cellular protein degradation. While taurine supplementation alone would be expected to exert a therapeutic effect far better than negligible in patients that have been exposed to high doses of ionizing radiation, it may on theoretical grounds be expected that much better results may be obtained by using taurine as part of a multifactorial treatment strategy, where it may interact synergistically with several other nutrients, hormones or other drugs for optimizing antioxidant protection and minimizing harmful posttraumatic inflammatory reactions, while using other nutrients to optimize DNA and tissue repair processes, and using a combination of good diet, immunostimulatory hormones and perhaps other nontoxic immunostimulants (such as beta-glucans) for optimizing the recovery of antiviral and antibacterial immune functions. Similar multifactorial treatment strategies may presumably be helpful in several other disease situations (including severe infectious diseases and severe asthma) as well as for treatment of acute intoxications or acute injuries (both mechanical ones and severe burns) where severely enhanced oxidative and/or nitrative stress and/or too much secretion of vasodilatory neuropeptides from C-fibres are important parts of the pathogenetic mechanisms that may lead to the death of the patient. Some case histories (with discussion of some of those mechanisms that may have been responsible for the observed therapeutic outcome) are given for illustration of the likely validity of these concepts and their relevance both for treatment of severe infections and non-infectious inflammatory diseases such as asthma and rheumatoid arthritis.

Therapeutic use of coenzyme Q10 and coenzyme Q10-related compounds and formulations

IMPORTANCE OF THE FIELD

Coenzyme Q(10) (CoQ(10)) is found in blood and in all organs. CoQ(10) deficiencies are due to autosomal recessive mutations, ageing-related oxidative stress and carcinogenesis processes, and also statin treatment. Many neurodegenerative disorders, diabetes, cancer and muscular and cardiovascular diseases have been associated with low CoQ(10) levels, as well as different ataxias and encephalomyopathies.

AREAS COVERED IN THIS REVIEW

We review the efficacy of a variety of commercial formulations which have been developed to solubilise CoQ(10) and promote its better absorption in vivo, and its use in the therapy of pathologies associated with low CoQ(10) levels, with emphasis in the results of the clinical trials. Also, we review the use of its analogues idebenone and MitoQ.

WHAT THE READER WILL GAIN

This review covers the most relevant aspects related with the therapeutic use of CoQ(10), including existing formulations and their effects on its bioavailability.

TAKE HOME MESSAGE

CoQ(10) does not cause serious adverse effects in humans and new formulations have been developed that increase CoQ(10) absorption. Oral CoQ(10) is a viable antioxidant strategy in many diseases, providing a significant to mild symptomatic benefit. Idebenone and MitoQ are promising substitutive CoQ(10)-related drugs which are well tolerated and safe.

Coenzyme Q10 improves diastolic function in children with idiopathic dilated cardiomyopathy

We aimed to determine the effect of supplementation with coenzyme Q10 on conventional therapy of children with cardiac failure due to idiopathic dilated cardiomyopathy. In a prospective, randomized, double-blinded, placebo-controlled trial, we randomized 38 patients younger than 18 years with idiopathic dilated cardiomyopathy to receive either coenzyme Q10, chosen for 17 patients, or placebo, administered in the remaining 21. Echocardiographic systolic and diastolic function parameters were determined for every patient at baseline, and after 6 months of supplementation. The index score for cardiac failure in children as established in New York was used for assessing the functional class of the patients. After 6 months supplementation, 10 patients randomized to receive coenzyme Q10 showed improvements in the grading of diastolic function, this being significantly more than that achieved by those randomized to the placebo group (p value = 0.011). The mean score for the index of cardiac failure index for those receiving coenzyme Q10 was also lower than the control group (p value = 0.024).Our results, therefore, indicate that administration of coenzyme Q10 is useful in ameliorating cardiac failure in patients with idiopathic dilated cardiomyopathy through its significant effect on improving diastolic function.

Coenzyme Q10 treatment reduces lipid peroxidation, inducible and endothelial nitric oxide synthases, and germ cell-specific apoptosis in a rat model of testicular ischemia/reperfusion injury

In this experimental study, we assessed the preventive effects of coenzyme Q(10) (CoQ(10)) in a rat model of ischemia/reperfusion injury. The results of this study show that CoQ(10) administration before the reperfusion period of testicular torsion provides a significant decrease in testicular lipid peroxidation products and expressions of inducible nitric oxide synthase, endothelial nitric oxide synthase, and germ cell-specific apoptosis.