Ubiquinol Improves Endothelial Function in Patients with Heart Failure with Reduced Ejection Fraction: A Single-Center, Randomized Double-Blind Placebo-Controlled Crossover Pilot Study

Effects of Pemafibrate and Eicosapentaenoic Acid Ethyl Ester on Endothelial Function in Patients With Hypertriglyceridemia and Coronary Artery Disease: A Study Protocol for a Multicenter, Open-Label Randomised Controlled Trial

Despite intensive low-density lipoprotein cholesterol-lowering therapies effectively reducing cardiovascular events, residual cardiovascular risks remain significant, with hypertriglyceridemia being an important contributing factor. Pemafibrate, a novel selective peroxisome proliferator-activated receptor alpha modulator, has shown strong triglyceride-lowering effects and potential vascular benefits. Similarly, eicosapentaenoic acid ethyl ester (EPA) has demonstrated cardiovascular protective effects, particularly in patients with hypertriglyceridemia. However, the comparative impact of these agents on endothelial function, a key marker of atherosclerotic progression, has not been thoroughly evaluated in patients with coronary artery disease (CAD). The PRIME (PRospective comparIson of peMafibrate and Eicosapentaenoic acid ethyl ester on vascular functions for hypertriglyceridemia) trial is a multi-center, open-label, randomised trial designed to compare the effects of pemafibrate and EPA on endothelial function in patients with CAD and hypertriglyceridemia. Patients receiving statin therapy with fasting triglyceride levels ≥150 mg/dL will be randomised into two groups: pemafibrate (0.2 mg/day, with possible dose escalation to 0.4 mg/day) or EPA (1800 mg/day, with possible dose escalation to 2700 mg/day). Endothelial function will be assessed with reactive hyperemia index (RHI). The primary endpoint is the change in RHI at 12 weeks. The secondary endpoints include the changes in RHI at 24 weeks, correlations between changes in RHI and changes in lipid biomarkers, and changes in biochemical parameters at 12 and 24 weeks. This study investigates the comparative effects of pemafibrate and EPA on endothelial function, addressing an unmet need in managing residual cardiovascular risk in patients with CAD. The findings will contribute to the optimisation of treatment strategies in patients with CAD and hypertriglyceridemia.

Efficacy and safety of coenzyme Q10 in heart failure: a meta-analysis of randomized controlled trials

BACKGROUND

The effectiveness and adverse effects of coenzyme Q10 for heart failure remain unclear owing to small sample sizes and variations in the quality of existing studies in literature.

METHODS

The databases of EMBASE, PubMed, Web of Science, CINAHL databases, Scopus, Cochrane Central Register of Controlled Trials, VIP, Wanfang, and CNKI were searched for randomized controlled trials on the coenzyme Q10-assisted treatment of heart failure. Relevant literature was retrieved, data were extracted, and the risk of bias of the included studies was evaluated by two investigators independently using the Review Manager 5.4 software and the STATA 15 software.

RESULTS

In total, 33 studies were included in this meta-analysis, which showed that all-cause mortality [RR = 0.64, 95% CI (0.48, 0.85), P = 0.002; GRADE: moderate quality], hospitalization for heart failure [RR = 0.50, 95% CI (0.37, 0.67), P < 0.00001; GRADE: moderate quality], New York Heart Association classification [MD = - 0.29, 95% CI (- 0.39, - 0.19), P < 0.00001; GRADE: low quality], and brain natriuretic peptide level [MD = - 91.97, 95% CI (- 103.11, - 80.83), P < 0.00001; GRADE: low quality] were lower in the coenzyme Q10 group than in the control group. Meanwhile, left ventricular ejection fraction [MD = 0.51, 95% CI (0.31, 0.71), P < 0.00001; GRADE: low quality] and 6-min walk test result [MD = 31.70, 95% CI (19.96, 43.43), P < 0.00001; GRADE: moderate quality] were better than those in the control group.

CONCLUSIONS

According to the existing evidence, coenzyme Q10 reduces all-cause mortality, hospitalization for heart failure, New York Heart Association classification, and brain natriuretic peptide level and improves left ventricular ejection fraction and 6-min walk test result in those with heart failure without major adverse effects.

TRIAL REGISTRATION

This study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO, http://www.crd.york.ac.uk/prospero ), with the registration number CRD42023493184.

Dietary strategies and nutritional supplements in the management of heart failure: a systematic review

Background and objective

Heart failure (HF) is a syndrome of increased intracardiac pressure or decreased cardiac output. There is a lack of conclusive evidence to recommend the regular use of any dietary supplement in patients with HF. However, certain studies have shown nutritional interventions to be beneficial for patients with HF. Therefore, the purpose of this systematic review was to understand and map the updates of dietary interventions and nutritional supplementation measures related to patients with HF over the past 5 years.

Study design

A systematic review.

Methods

The PubMed, Web of Science, Scopus, and Cochrane Library databases were searched for randomized clinical trials on the association between dietary interventions and nutritional supplements and HF published between 2018 and 2023. A total of 1755 documents were retrieved, of which 19 were finalized for inclusion.

Results

The findings suggest that individualized nutritional support reduces mortality and risk of major cardiovascular events in chronic heart failure inpatients at high nutritional risk. The Mediterranean diet improves functionality, quality of life, and cardiac function. Additionally, supplementation with thiamine, ubiquinol, D-ribose, and L-arginine enhances left ventricular ejection fraction. Probiotic yogurt may effectively improve the inflammatory and antioxidative status of chronic heart failure. Whey protein and melatonin have a positive effect on improving endothelial function in HF patients.

Conclusion

Certain dietary interventions and nutritional supplements may provide some benefit to patients with HF. However, there is no relevant definitive evidence on the impact of nutritional interventions on the prognosis of HF, and more high-quality clinical trials are needed for further in-depth studies.

Systematic review registration

Identifier, CRD42024510847.

The Association between Food Groups, Nutraceuticals, and Food Supplements Consumption on Vascular Health Outcomes: A Literature Review

Vascular aging, marked by alterations in the structure and function of blood vessels, including heightened arterial stiffness and impaired endothelial function, is linked to a higher likelihood of developing cardiovascular and age-associated pathological conditions. Oxidative stress and inflammation are key stimulation factors in vascular aging. Engaging in healthy dietary habits could enhance the functioning of blood vessels. The aim of this study was to conduct a literature review of the evidence regarding the relationship between food regimens, nutraceuticals, and dietary supplements and vascular health. A search of electronic databases, including PubMed, Scopus, and Web of Science Core Collection, was performed. Experimental and observational studies evaluating the association between food groups, nutraceuticals, supplements, and endothelial function and/or arterial stiffness were deemed eligible for this narrative review. Based on the current body of the included studies, food groups, nutraceuticals, and dietary supplements may not demonstrate superiority over placebos in enhancing markers of vascular health. To obtain more reliable evidence on the effectiveness of interventions in vascular health, additional RCTs with larger sample sizes, extended follow-up periods, and multi-center participation are necessary. Enhancing the credibility of these RCTs requires better control of dietary variables and more precise measurement of vascular health markers.

Effect of Coenzyme Q10 on early wound healing after recession coverage surgery with the modified coronally advanced tunnel technique and a connective tissue graft: A 6-month, triple-blinded, randomized, placebo-controlled pilot trial

OBJECTIVES

Coenzyme Q10 (CoQ10) or ubiquinone is one of a cell's most important electron carriers during oxidative phosphorylation and many other cellular processes. As a strong anti-oxidant with further anti-inflammatory effects CoQ10 is of potential therapeutical value. The aim of this randomized controlled clinical trial was to investigate the effect of topical CoQ10 on early wound healing after recession coverage surgery using the modified coronally advanced tunnel (MCAT) and palatal connective tissue graft (CTG).

MATERIALS AND METHODS

Thirty patients with buccal gingival recessions were evaluated after being randomly allocated to: 1) MCAT and CTG with topical application of a coenzyme Q10 spray for 21 days or 2) MCAT and CTG with placebo spray. Wound healing was evaluated by the early wound healing index (EHI). Patient-reported pain was analyzed by a 100-mm visual analogue scale (VAS) at day 2, 7, 14 and 21 post-surgically. Mean recession coverage, gain of keratinized tissue and esthetic outcomes were assessed at 6 months.

RESULTS

EHI and pain scores showed no significant differences. Time to recovery defined as VAS<10 mm was shorter in the test group. Mean root coverage after 6 months was 84.62 ± 26.57% and 72.19 ± 26.30% for test and placebo, p=0.052. Complete root coverage was obtained in 9 (60%) test and in 2 (13.3%) placebo patients. Increase in keratinized tissue width and esthetical outcomes were similar for both groups.

CONCLUSION

CoQ10 had no significant effect on early wound healing and on mean root coverage after 6 months.

CLINICAL RELEVANCE

Early wound healing: in young healthy patients with no inflammatory oral conditions topical CoQ10 does not improve early healing.

Comparison of Coenzyme Q10 (Ubiquinone) and Reduced Coenzyme Q10 (Ubiquinol) as Supplement to Prevent Cardiovascular Disease and Reduce Cardiovascular Mortality

PURPOSE OF REVIEW

According to the World Health Organization (WHO), cardiovascular disease is the leading cause of death worldwide. Heart failure has been defined as a global pandemic leading to millions of deaths. Recent research clearly approved the beneficial effect of Coenzyme Q10 supplementation in treatment and prevention of cardiovascular disease in patients with heart failure in clinical trials but did not distinguish between the oxidised form CoQ10 and reduced form CoQH2 of Coenzyme Q10. The aim of this study is to determine differences in medical application of CoQ10 and CoQH2 supplementation and evaluate the efficacy of CoQ10 and CoQH2 supplementation to prevent cardiovascular disease in patients with heart failure.

RECENT FINDINGS

A PubMed search for the terms "ubiquinone" and "ubiquinol" was conducted, and 28 clinical trials were included. Our findings go along with the biochemical description of CoQ10 and CoQH2, recording cardiovascular benefits for CoQ10 and antioxidative and anti-inflammatory properties for CoQH2. Our main outcomes are the following: (I) CoQ10 supplementation reduced cardiovascular death in patients with heart failure. This is not reported for CoQH2. (II) Test concentrations leading to cardiovascular benefits are much lower in CoQ10 studies than in CoQH2 studies. (III) Positive long-term effects reducing cardiovascular mortality are only observed in CoQ10 studies. Based on the existing literature, the authors recommend CoQ10 instead of CoQH2 to treat and prevent cardiovascular disease in patients with heart failure.

Ubiquinol preserves immune cells in gamma-irradiated rats: Role of autophagy and apoptosis in splenic tissue

Radiation has been applied in cancer treatment to eradicate tumors and displayed great therapeutic benefits for humans. However, it is associated with negative impacts on normal cells, not only cancer cells. Irradiation can trigger cell death through several mechanisms, such as apoptosis, necrosis, and autophagy. This study aimed to investigate the radioprotective efficacy of ubiquinol against radiation-induced splenic tissue injury in animals and the related involved mechanisms. Animals were classified into four groups: group 1 (normal untreated rats) received vehicle 5 % Tween 80; group 2 received 7 Gy γ-radiation; group 3 received 10 mg/Kg oral ubiquinol post-irradiation; and group 4 received 10 mg/Kg oral ubiquinol before and after (pre/post-) irradiation. Ubiquinol restored the spleen histoarchitecture, associated with improved immunohistochemical quantification of B and T lymphocyte markers and ameliorated hematological alterations induced by irradiation. Such effects may be due to an enhanced antioxidant pathway through stimulation of p62, Nrf2, and GSH, associated with reduced Keap1 and MDA. Moreover, ubiquinol decreased mTOR, thus enhanced autophagy markers viz. LC3-II. Furthermore, ubiquinol showed an antiapoptotic effect by enhancing Bcl-2 and reducing caspase-3 and Bax. Consequently, ubiquinol exerts a splenic-protective effect against irradiation via enhancing antioxidant, autophagic, and survival pathways.

Combined Supplementation of Coenzyme Q10 and Other Nutrients in Specific Medical Conditions

Coenzyme Q10 (CoQ10) is a compound with a crucial role in mitochondrial bioenergetics and membrane antioxidant protection. Despite the ubiquitous endogenous biosynthesis, specific medical conditions are associated with low circulating CoQ10 levels. However, previous studies of oral CoQ10 supplementation yielded inconsistent outcomes. In this article, we reviewed previous CoQ10 trials, either single or in combination with other nutrients, and stratified the study participants according to their metabolic statuses and medical conditions. The CoQ10 supplementation trials in elders reported many favorable outcomes. However, the single intervention was less promising when the host metabolic statuses were worsening with the likelihood of multiple nutrient insufficiencies, as in patients with an established diagnosis of metabolic or immune-related disorders. On the contrary, the mixed CoQ10 supplementation with other interacting nutrients created more promising impacts in hosts with compromised nutrient reserves. Furthermore, the results of either single or combined intervention will be less promising in far-advanced conditions with established damage, such as neurodegenerative disorders or cancers. With the limited high-level evidence studies on each host metabolic category, we could only conclude that the considerations of whether to take supplementation varied by the individuals' metabolic status and their nutrient reserves. Further studies are warranted.

Effects of Ubiquinol and/or D-ribose in Patients With Heart Failure With Preserved Ejection Fraction

Patients with heart failure with preserved ejection fraction (HFpEF) have few pharmacologic therapies, and it is not known if supplementing with ubiquinol and/or d-ribose could improve outcomes. The overall objective of this study was to determine if ubiquinol and/or d-ribose would reduce the symptoms and improve cardiac performance in patients with HFpEF. This was a phase 2 randomized, double-blind, placebo-controlled trial of 216 patients with HFpEF who were ≥ 50 years old with a left ventricular ejection fraction (EF) ≥ 50%. A total of 4 study groups received various supplements over 12 weeks: Group 1 received placebo ubiquinol capsules and d-ribose powder, Group 2 received ubiquinol capsules (600 mg/d) and placebo d-ribose powder, Group 3 received placebo ubiquinol capsules with d-ribose powder (15 g/d), and Group 4 received ubiquinol capsules and d-ribose powder. There were 7 outcome measures for this study: Kansas City Cardiomyopathy Questionnaire (KCCQ) clinical summary score, level of vigor using a subscale from the Profile of Mood States, EF, the ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity (septal E/e' ratio), B-type natriuretic peptides, lactate/adenosine triphosphate ratio, and the 6-minute walk test. Treatment with ubiquinol and/or d-ribose significantly improved the KCCQ clinical summary score (17.30 to 25.82 points), vigor score (7.65 to 8.15 points), and EF (7.08% to 8.03%) and reduced B-type natriuretic peptides (-72.02 to -47.51) and lactate/adenosine triphosphate ratio (-4.32 to -3.35 × 10^-4). There were no significant increases in the septal E/e' or the 6-minute walk test. In conclusion, ubiquinol and d-ribose reduced the symptoms of HFpEF and increased the EF. These findings support the use of these supplements in addition to standard therapeutic treatments for patients with HFpEF.

Heart Failure—Do We Need New Drugs or Have Them Already? A Case of Coenzyme Q10

Heart failure (HF) is a global epidemic that contributes to the deterioration of quality of life and its shortening in 1–3% of adult people in the world. Pharmacotherapy of HF should rely on highly effective drugs that improve prognosis and prolong life. Currently, the ESC guidelines from 2021 indicate that ACEI, ARNI, BB, and SGLT2 inhibitors are the first-line drugs in HF. It is also worth remembering that the use of coenzyme Q10 brought many benefits in patients with HF. Coenzyme Q10 is a very important compound that performs many functions in the human body. The most important function of coenzyme Q10 is participation in the production of energy in the mitochondria, which determines the proper functioning of all cells, tissues, and organs. The highest concentration of coenzyme Q10 is found in the tissue of the heart muscle. As the body ages, the concentration of coenzyme Q10 in the tissue of the heart muscle decreases, which makes it more susceptible to damage by free radicals. It has been shown that in patients with HF, the aggravation of disease symptoms is inversely related to the concentration of coenzyme Q10. Importantly, the concentration of coenzyme Q10 in patients with HF was an important predictor of the risk of death. Long-term coenzyme Q10 supplementation at a dose of 300 mg/day (Q-SYMBIO study) has been shown to significantly improve heart function and prognosis in patients with HF. This article summarizes the latest and most important data on CoQ10 in pathogenesis.

Coenzyme Q10 to manage chronic heart failure with a reduced ejection fraction: a systematic review and economic evaluation

BACKGROUND

Chronic heart failure is a debilitating condition that accounts for an annual NHS spend of £2.3B. Low levels of endogenous coenzyme Q10 may exacerbate chronic heart failure. Coenzyme Q10 supplements might improve symptoms and slow progression. As statins are thought to block the production of coenzyme Q10, supplementation might be particularly beneficial for patients taking statins.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of coenzyme Q10 in managing chronic heart failure with a reduced ejection fraction.

METHODS

A systematic review that included randomised trials comparing coenzyme Q10 plus standard care with standard care alone in chronic heart failure. Trials restricted to chronic heart failure with a preserved ejection fraction were excluded. Databases including MEDLINE, EMBASE and CENTRAL were searched up to March 2020. Risk of bias was assessed using the Cochrane Risk of Bias tool (version 5.2). A planned individual participant data meta-analysis was not possible and meta-analyses were mostly based on aggregate data from publications. Potential effect modification was examined using meta-regression. A Markov model used treatment effects from the meta-analysis and baseline mortality and hospitalisation from an observational UK cohort. Costs were evaluated from an NHS and Personal Social Services perspective and expressed in Great British pounds at a 2019/20 price base. Outcomes were expressed in quality-adjusted life-years. Both costs and outcomes were discounted at a 3.5% annual rate.

RESULTS

A total of 26 trials, comprising 2250 participants, were included in the systematic review. Many trials were reported poorly and were rated as having a high or unclear risk of bias in at least one domain. Meta-analysis suggested a possible benefit of coenzyme Q10 on all-cause mortality (seven trials, 1371 participants; relative risk 0.68, 95% confidence interval 0.45 to 1.03). The results for short-term functional outcomes were more modest or unclear. There was no indication of increased adverse events with coenzyme Q10. Meta-regression found no evidence of treatment interaction with statins. The base-case cost-effectiveness analysis produced incremental costs of £4878, incremental quality-adjusted life-years of 1.34 and an incremental cost-effectiveness ratio of £3650. Probabilistic sensitivity analyses showed that at thresholds of £20,000 and £30,000 per quality-adjusted life-year coenzyme Q10 had a high probability (95.2% and 95.8%, respectively) of being more cost-effective than standard care alone. Scenario analyses in which the population and other model assumptions were varied all found coenzyme Q10 to be cost-effective. The expected value of perfect information suggested that a new trial could be valuable.

LIMITATIONS

For most outcomes, data were available from few trials and different trials contributed to different outcomes. There were concerns about risk of bias and whether or not the results from included trials were applicable to a typical UK population. A lack of individual participant data meant that planned detailed analyses of effect modifiers were not possible.

CONCLUSIONS

Available evidence suggested that, if prescribed, coenzyme Q10 has the potential to be clinically effective and cost-effective for heart failure with a reduced ejection fraction. However, given important concerns about risk of bias, plausibility of effect sizes and applicability of the evidence base, establishing whether or not coenzyme Q10 is genuinely effective in a typical UK population is important, particularly as coenzyme Q10 has not been subject to the scrutiny of drug-licensing processes. Stronger evidence is needed before considering its prescription in the NHS.

FUTURE WORK

A new independent, well-designed clinical trial of coenzyme Q10 in a typical UK heart failure with a reduced ejection fraction population may be warranted.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018106189.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 4. See the NIHR Journals Library website for further project information.

Coenzyme Q at the Hinge of Health and Metabolic Diseases

Coenzyme Q is a unique lipidic molecule highly conserved in evolution and essential to maintaining aerobic metabolism. It is endogenously synthesized in all cells by a very complex pathway involving a group of nuclear genes that share high homology among species. This pathway is tightly regulated at transcription and translation, but also by environment and energy requirements. Here, we review how coenzyme Q reacts within mitochondria to promote ATP synthesis and also integrates a plethora of metabolic pathways and regulates mitochondrial oxidative stress. Coenzyme Q is also located in all cellular membranes and plasma lipoproteins in which it exerts antioxidant function, and its reaction with different extramitochondrial oxidoreductases contributes to regulate the cellular redox homeostasis and cytosolic oxidative stress, providing a key factor in controlling various apoptosis mechanisms. Coenzyme Q levels can be decreased in humans by defects in the biosynthesis pathway or by mitochondrial or cytosolic dysfunctions, leading to a highly heterogeneous group of mitochondrial diseases included in the coenzyme Q deficiency syndrome. We also review the importance of coenzyme Q levels and its reactions involved in aging and age-associated metabolic disorders, and how the strategy of its supplementation has had benefits for combating these diseases and for physical performance in aging.

Role of Coenzyme Q10 in Health and Disease: An Update on the Last 10 Years (2010-2020)

The present review focuses on preclinical and clinical studies conducted in the last decade that contribute to increasing knowledge on Coenzyme Q₁₀'s role in health and disease. Classical antioxidant and bioenergetic functions of the coenzyme have been taken into consideration, as well as novel mechanisms of action involving the redox-regulated activation of molecular pathways associated with anti-inflammatory activities. Cardiovascular research and fertility remain major fields of application of Coenzyme Q₁₀, although novel applications, in particular in relation to topical application, are gaining considerable interest. In this respect, bioavailability represents a major challenge and the innovation in formulation aspects is gaining critical importance.

Effect of Dietary Coenzyme Q10 Plus NADH Supplementation on Fatigue Perception and Health-Related Quality of Life in Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, multisystem, and profoundly debilitating neuroimmune disease, probably of post-viral multifactorial etiology. Unfortunately, no accurate diagnostic or laboratory tests have been established, nor are any universally effective approved drugs currently available for its treatment. This study aimed to examine whether oral coenzyme Q10 and NADH (reduced form of nicotinamide adenine dinucleotide) co-supplementation could improve perceived fatigue, unrefreshing sleep, and health-related quality of life in ME/CFS patients. A 12-week prospective, randomized, double-blind, placebo-controlled trial was conducted in 207 patients with ME/CFS, who were randomly allocated to one of two groups to receive either 200 mg of CoQ10 and 20 mg of NADH (n = 104) or matching placebo (n = 103) once daily. Endpoints were simultaneously evaluated at baseline, and then reassessed at 4- and 8-week treatment visits and four weeks after treatment cessation, using validated patient-reported outcome measures. A significant reduction in cognitive fatigue perception and overall FIS-40 score (p < 0.001 and p = 0.022, respectively) and an improvement in HRQoL (health-related quality of life (SF-36)) (p < 0.05) from baseline were observed within the experimental group over time. Statistically significant differences were also shown for sleep duration at 4 weeks and habitual sleep efficiency at 8 weeks in follow-up visits from baseline within the experimental group (p = 0.018 and p = 0.038, respectively). Overall, these findings support the use of CoQ10 plus NADH supplementation as a potentially safe therapeutic option for reducing perceived cognitive fatigue and improving the health-related quality of life in ME/CFS patients. Future interventions are needed to corroborate these clinical benefits and also explore the underlying pathomechanisms of CoQ10 and NADH administration in ME/CFS.

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.

The Use of Coenzyme Q10 in Cardiovascular Diseases

CoQ10 is an endogenous antioxidant produced in all cells that plays an essential role in energy metabolism and antioxidant protection. CoQ10 distribution is not uniform among different organs, and the highest concentration is observed in the heart, though its levels decrease with age. Advanced age is the major risk factor for cardiovascular disease and endothelial dysfunction triggered by oxidative stress that impairs mitochondrial bioenergetic and reduces NO bioavailability, thus affecting vasodilatation. The rationale of the use of CoQ10 in cardiovascular diseases is that the loss of contractile function due to an energy depletion status in the mitochondria and reduced levels of NO for vasodilatation has been associated with low endogenous CoQ10 levels. Clinical evidence shows that CoQ10 supplementation for prolonged periods is safe, well-tolerated and significantly increases the concentration of CoQ10 in plasma up to 3–5 µg/mL. CoQ10 supplementation reduces oxidative stress and mortality from cardiovascular causes and improves clinical outcome in patients undergoing coronary artery bypass graft surgery, prevents the accumulation of oxLDL in arteries, decreases vascular stiffness and hypertension, improves endothelial dysfunction by reducing the source of ROS in the vascular system and increases the NO levels for vasodilation.

CoenzymeQ in cellular redox regulation and clinical heart failure

Coenzyme Q (CoQ) is ubiquitously embedded in lipid bilayers of various cellular organelles. As a redox cycler, CoQ shuttles electrons between mitochondrial complexes and extramitochondrial reductases and oxidases. In this way, CoQ is crucial for maintaining the mitochondrial function, ATP synthesis, and redox homeostasis. Cardiomyocytes have a high metabolic rate and rely heavily on mitochondria to provide energy. CoQ levels, in both plasma and the heart, correlate with heart failure in patients, indicating that CoQ is critical for cardiac function. Moreover, CoQ supplementation in clinics showed promising results for treating heart failure. This review provides a comprehensive view of CoQ metabolism and its interaction with redox enzymes and reactive species. We summarize the clinical trials and applications of CoQ in heart failure and discuss the caveats and future directions to improve CoQ therapeutics.

A systematic review for the efficacy of coenzyme Q10 in patients with chronic kidney disease

BACKGROUND

The effects of coenzyme Q10 (CoQ10) supplementation in chronic kidney disease (CKD) patients remain controversial.

OBJECTIVE

A systematic review of current evidence was performed to systematically and comprehensively summarize the effects of CoQ10 on cardiovascular outcomes, oxidative stress, inflammation, lipid profiles, and glucose metabolism.

METHODS

MEDLINE, EMBASE, and the Cochrane Library database (Cochrane Central Register of Controlled Trials) were searched to identify eligible studies investigating the effects of CoQ10 supplementation on patients with CKD.

RESULTS

Twelve independent studies (including seventeen publications) were included in this systematic review. For CKD patients, six studies reported variable cardiovascular outcomes, which yielded inconsistent results. Regarding oxidative stress and inflammation, pooled analysis showed that CoQ10 supplementation significantly reduced malonaldehyde (WMD: - 1.15 95% CI - 1.48 to - 0.81) and high-sensitivity C reactive protein levels (WMD: - 1.18 95% CI - 2.21 to - 0.15). Regarding glucose metabolism, we found that CoQ10 supplementation resulted in significant improvements in HbA1c (WMD: - 0.80; 95% CI: - 1.35 to - 0.24) and QUICKI (WMD: 0.02; 95% CI: 0.01 to 0.03). The pooled results indicated that CoQ10 supplementation had no effects on total cholesterol, or LDL-cholesterol, or on HDL-cholesterol, and triglycerides.

CONCLUSIONS

Our systematic review demonstrated that CoQ10 supplementation might have promising effects on oxidative stress. This work provided some clues that CoQ10 supplementation might have the potential to improve inflammation levels, glucose metabolism, cardiac structure, and cardiac biomarkers. However, the effects of CoQ10 supplementation should be confirmed in larger high-quality studies.

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.

Associations of coenzyme Q10 with endothelial function in hemodialysis patients

BACKGROUND

Endothelial dysfunction is common in patients undergoing hemodialysis (HD). However, little is known about the relationship between endothelial dysfunction and coenzyme Q10 (CoQ10) levels in HD patients.

METHODS

Eligible HD patients were enrolled in this study according to prespecified inclusion and exclusion criteria. Endothelial function was assessed by brachial artery flow-mediated dilation (FMD). Plasma CoQ10, serum malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) levels were measured. The potential confounders identified by univariate analyses (P < 0.15) were selected in a stepwise multiple regression model.

RESULTS

In total, 111 HD patients were enrolled in this study. The mean CoQ10 level was 633.53 ± 168.66 ng/mL, and endothelial dysfunction was prevalent (91.0%) using a cut-off value of 10% FMD. A significant correlation was observed between FMD and plasma CoQ10 level (r = 0.727, P < 0.001). After adjusting for potential parameters, a stepwise multivariate linear regression analysis revealed that CoQ10 level was an independent predictor of FMD (β = 0.018, P < 0.001). When CoQ10 was dichotomized using the median value (639.74 ng/mL), the conclusion remained unchanged (β = 0.584, P < 0.001). Pearson's correlation analyses revealed that plasma CoQ10 level was negatively correlated with MDA (r = -0.48, P < 0.001) and 8-OHdG (r = -0.43, P < 0.001) levels.

CONCLUSION

Our data demonstrate that impaired brachial artery FMD was common in HD patients. CoQ10 level was independently associated with FMD, and oxidative stress may constitute a link between CoQ10 level and endothelial dysfunction in these patients.