The effect of coenzyme Q10 administration on metabolic control in patients with type 2 diabetes mellitus

Coenzyme Q10 and Endocrine Disorders: An Overview

Mitochondrial dysfunction and oxidative stress have been implicated in the pathogenesis of a number of endocrine disorders; this, in turn, suggests a potential role for the vitamin-like substance coenzyme Q10 (CoQ10) in the pathogenesis and treatment of these disorders, on the basis of its key roles in mitochondrial function, and as an antioxidant. In this article we have therefore reviewed the role of CoQ10 deficiency and supplementation in disorders of the thyroid, pancreas, gonads, pituitary and adrenals, with a particular focus on hyperthyroidism, type II diabetes, male infertility and polycystic ovary syndrome.

CoQ Regulates Brown Adipose Tissue Respiration and Uncoupling Protein 1 Expression

Coenzyme Q (CoQ, aka ubiquinone) is a key component of the mitochondrial electron transport chain (ETC) and membrane-incorporated antioxidant. CoQ10 deficiencies encompass a heterogeneous spectrum of clinical phenotypes and can be caused by hereditary mutations in the biosynthesis pathway or result from pharmacological interventions such as HMG-CoA Reductase inhibitors, and statins, which are widely used to treat hypercholesterolemia and prevent cardiovascular disease. How CoQ deficiency affects individual tissues and cell types, particularly mitochondrial-rich ones such as brown adipose tissue (BAT), has remained poorly understood. Here we show that pharmacological and genetic models of BAT CoQ deficiency show altered respiration that can only in part be explained by classical roles of CoQ in the respiration chain. Instead, we found that CoQ strongly impacts brown and beige adipocyte respiration via the regulation of uncoupling protein 1 (UCP1) expression. CoQ deficiency in BAT robustly decreases UCP1 protein levels and uncoupled respiration unexpectedly, resulting in increased inner mitochondrial membrane potential and decreased ADP/ATP ratios. Suppressed UCP1 expression was also observed in a BAT-specific in vivo model of CoQ deficiency and resulted in enhanced cold sensitivity. These findings demonstrate an as yet unappreciated role of CoQ in the transcriptional regulation of key thermogenic genes and functions.

Effects of Coenzyme Q10 Supplementation on Lipid Profiles in Adults: A Meta-analysis of Randomized Controlled Trials

CONTEXT

Previous meta-analyses have suggested that the effects of coenzyme Q10 (CoQ10) on lipid profiles remain debatable. Additionally, no meta-analysis has explored the optimal intake of CoQ10 for attenuating lipid profiles in adults.

OBJECTIVE

This study conducted a meta-analysis to determine the effects of CoQ10 on lipid profiles and assess their dose-response relationships in adults.

METHODS

Databases (Web of Science, PubMed/Medline, Embase, and the Cochrane Library) were systematically searched until August 10, 2022. The random effects model was used to calculate the mean differences (MDs) and 95% CI for changes in circulating lipid profiles. The novel single-stage restricted cubic spline regression model was applied to explore nonlinear dose-response relationships.

RESULTS

Fifty randomized controlled trials with a total of 2794 participants were included in the qualitative synthesis. The pooled analysis revealed that CoQ10 supplementation significantly reduced total cholesterol (TC) (MD -5.53 mg/dL; 95% CI -8.40, -2.66; I2 = 70%), low-density lipoprotein cholesterol (LDL-C) (MD -3.03 mg/dL; 95% CI -5.25, -0.81; I2 = 54%), and triglycerides (TGs) (MD -9.06 mg/dL; 95% CI -14.04, -4.08; I2 = 65%) and increased high-density lipoprotein cholesterol (HDL-C) (MD 0.83 mg/dL; 95% CI 0.01, 1.65; I2 = 82%). The dose-response analysis showed an inverse J-shaped nonlinear pattern between CoQ10 supplementation and TC in which 400-500 mg/day CoQ10 largely reduced TC (χ2 = 48.54, P < .01).

CONCLUSION

CoQ10 supplementation decreased the TC, LDL-C, and TG levels, and increased HDL-C levels in adults, and the dosage of 400 to 500 mg/day achieved the greatest effect on TC.

Effects of curcumin and/or coenzyme Q10 supplementation on metabolic control in subjects with metabolic syndrome: a randomized clinical trial

Background

Metabolic syndrome (MetS) as a cluster of conditions including hyperlipidemia, hypertension, hyperglycemia, insulin resistance, and abdominal obesity is linked to cardiovascular diseases and type 2 diabetes. Evidence suggested that intake of curcumin and coenzyme Q10 may have therapeutic effects in the management of MetS.

Aims

We investigated the effects of curcumin and/or coenzyme Q10 supplementation on metabolic syndrome components including systolic blood pressure (SBP), diastolic blood pressure (DBP), waist circumference (WC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-c) and fasting plasma glucose (FPG) as primary outcomes, and total cholesterol (TC), low density lipoprotein-cholesterol (LDL-c) and body mass index (BMI) as secondary outcomes in subjects with MetS.

Methods

In this 2 × 2 factorial, randomized, double-blinded, placebo-controlled study, 88 subjects with MetS were randomly assigned into four groups including curcumin plus placebo (CP), or coenzyme Q10 plus placebo (QP), or curcumin plus coenzyme Q10 (CQ), or double placebo (DP) for 12 weeks.

Results

The CP group compared with the three other groups showed a significant reduction in HDL-c (P = 0.001), TG (P <  0.001), TC (P <  0.001), and LDL-c (P <  0.001). No significant differences were seen between the four groups in terms of SBP, DBP, FPG, WC, BMI and weight.

Conclusion

Curcumin improved dyslipidemia, but had no effect on body composition, hypertension and glycemic control. Furthermore, coenzyme Q10 as well as the combination of curcumin and coenzyme Q10 showed no therapeutic effects in subjects with MetS. The trial was registered on 09/21/2018 at the Iranian clinical trials website (IRCT20180201038585N2), URL: https://www.irct.ir/trial/32518.

Effects of coenzyme Q10 supplementation on glycemic control: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

Background

Previous reviews reported that the effects of CoQ10 on glycemic control were inconsistent. There is no review exploring the optimal intake of CoQ10 for glycemic control. We aimed to investigate the efficacy of CoQ10 on glycemic control and evaluate the dose-response relationship via integrating the existing evidence from randomized control trials (RCTs).

Methods

Databases (PubMed, Embase, and Cochrane Library) were searched to identify RCTs for investigating the efficacy of CoQ10 on fasting glucose, fasting insulin, HbA1c, and HOMA-IR up to March 12, 2022. We performed a meta-analysis on 40 RCTs of CoQ10. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated for net changes. Evidence certainty was assessed using GRADE. Dose-response relationships were evaluated using 1-stage restricted cubic spline regression model. The protocol was registered in PROSPERO (CRD42021252933).

Findings

Forty studies (n = 2,424 participants) were included in this meta-analysis. CoQ10 significantly reduced fasting glucose (WMD: -5.22 [95% CI: -8.33, -2.11] mg/dl; P <0.001; I2 =95.10%), fasting insulin (-1.32 [-2.06, -0.58] μIU/ml; P < 0.001; I2 =78.86%), HbA1c (-0.12% [-0.23, -0.01]; P =0.04; I2 =49.10%), and HOMA-IR (-0.69 [-1.00, -0.38]; P <0.001; I2 =88.80%). The effect of CoQ10 on outcomes was greater in diabetes with lower heterogeneity. A "U" shape dose-response relationship curve revealed that 100-200 mg/day of CoQ10 largely decreased fasting glucose (χ 2 = 12.08, P nonlinearity =0.002), fasting insulin (χ 2 = 9.73, P nonlinearity =0.008), HbA1c (χ 2 = 6.00, P nonlinearity =0.049), HOMA-IR (χ 2 = 25.89, P nonlinearity <0.001).

Interpretation

CoQ10 supplementation has beneficial effects on glycemic control, especially in diabetes, and 100-200 mg/day of CoQ10 could achieve the greatest benefit, which could provide a basis for the dietary guidelines of CoQ10 in patients with glycemic disorders.

Funding

This work was supported by the National Natural Science Foundation of China (No. 82030098, 81872617 and 81730090), Shenzhen Science, Technology, and Innovation Commission (No. JCYJ20180307153228190), CNS Research Fund for DRI, and National innovation and entrepreneurship training program for undergraduate student (No. 202210558161).

Dose-Response Effect of Coenzyme Q10 Supplementation on Blood Pressure among Patients with Cardiometabolic Disorders: A Grading of Recommendations Assessment, Development, and Evaluation (GRADE)-Assessed Systematic Review and Meta-Analysis of Randomized Controlled Trials

Previous studies have shown beneficial effects of coenzyme Q10 (CoQ10) supplementation on blood pressure (BP). However, the optimal intake of CoQ10 for BP regulation in patients with cardiometabolic disorders is unknown, and its effect on circulating CoQ10 is also unclear. We aimed to assess the dose-response relation between CoQ10 and BP, and quantify the effect of CoQ10 supplementation on the concentration of circulating CoQ10 by synthesizing available evidence from randomized controlled trials (RCTs). A comprehensive literature search was performed in 3 databases (PubMed/MEDLINE, Embase, and Cochrane Library) to 21 March, 2022. A novel 1-stage restricted cubic spline regression model was used to evaluate the nonlinear dose-response relation between CoQ10 and BP. Twenty-six studies comprising 1831 subjects were included in our meta-analysis. CoQ10 supplementation significantly reduced systolic blood pressure (SBP) (-4.77 mmHg, 95% CI: -6.57, -2.97) in patients with cardiometabolic diseases; this reduction was accompanied by a 1.62 (95% CI: 1.26, 1.97) μg/mL elevation of circulating CoQ10 compared with the control group. Subgroup analyses revealed that the effects of reducing SBP were more pronounced in patients with diabetes and dyslipidemia and in studies with longer durations (>12 wk). Importantly, a U-shaped dose-response relation was observed between CoQ10 supplementation and SBP level, with an approximate dose of 100-200 mg/d largely reducing SBP (χ2 = 10.84, Pnonlinearity = 0.004). The quality of evidence was rated as moderate, low, and very low for SBP, diastolic blood pressure (DBP), and circulating CoQ10 according to the Grading of Recommendations, Assessment, Development, and Evaluation approach (GRADE), respectively. The current finding demonstrated that the clinically beneficial effects of CoQ10 supplementation may be attributed to the reduction in SBP, and 100-200 mg/d of CoQ10 supplementation may achieve the greatest benefit on SBP in patients with cardiometabolic diseases. This study was registered on PROSPERO as CRD42021252933.

Could nutrient supplements provide additional glycemic control in diabetes management? A systematic review and meta-analysis of randomized controlled trials of as an add-on nutritional supplementation therapy

This systematic review and meta-analysis assessed the antidiabetic effect of pharmaconutrients as an add-on in type 2 diabetes mellitus patients by pooling data from currently available randomized controlled trials (RCTs). Data sources included the PubMed and EMBASE, Cochrane Central Register of Controlled Trials. RCTs reporting changes in glycosylated hemoglobin (HbA1c), fasting blood glucose (FBG), or homeostasis model assessment of insulin resistance (HOMA-IR) levels following add-on pharmaconutritional therapies for T2DM patients consuming antidiabetic drugs were targeted. Using random-effects meta-analyses, we identified pharmaconutrients with effects on glycemic outcomes. Heterogeneity among studies was presented using I² values. Among 9537 articles, 119 RCTs with nine pharmaconutrients (chromium; coenzyme Q10; omega-3 fatty acids; vitamins C, D, and E; alpha-lipoic acid; selenium; and zinc) were included. Chromium (HbA1c, FBG, and HOMA-IR), coenzyme Q10 (HbA1c and FBG), vitamin C (HbA1c and FBG), and vitamin E (HbA1c and HOMA-IR) significantly improved glycemic control. Baseline HbA1c level and study duration influenced the effects of chromium and vitamin E on HbA1c level. Sensitivity analyses did not modify the pooled effects of pharmaconutrients on glycemic control. Administration of chromium, coenzyme Q10, and vitamins C and E for T2DM significantly improved glycemic control. This study has been registered in PROSPERO (CRD42018115229).

Coenzyme Q10 in COPD: An Unexplored Opportunity?

COPD represents a major cause of mortality and morbidity worldwide, is linked to systemic inflammation and tends to coexist with a variety of comorbidities. Inflammation, oxidative stress and protease-antiprotease imbalance represent the pathogenic triad of COPD. Even though oxidative stress and mitochondrial dysfunction is a well-studied phenomenon in COPD and there is a variety of studies that aim to counteract its effect, there is limited data available on the use of coenzyme Q10 in COPD. The aim of the current review is to analyze the current data on the use of coenzyme Q10 in the management of COPD and frequently encountered comorbidities.

Effects of Coenzyme Q10 Supplementation on Anthropometric Indices in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background:

Obesity is related to increase in the incidence of morbidity and mortality. Previous studies have led to conflicting results regarding the effect of coenzyme Q10 (CoQ10) supplementation on anthropometric indices. This study aimed to evaluate the efficacy of CoQ10 supplementation on body weight, body mass index (BMI), and waist circumference (WC) through a systematic review and meta-analysis of randomized controlled trials (RCTs).

Methods:

PubMed, Scopus, Web of Science, and Cochrane Library as well as the reference lists of the identified relevant RCTs were searched up to March 2019, and weighted mean differences (WMDs) were pooled by using the random-effects model.

Results:

Twenty RCTs (976 participants) were eligible to be included in the systematic review. The meta-analysis revealed that CoQ10 supplementation had no effect on body weight (WMD = −0.04 kg; 95% confidence interval [CI]: −1.96, 1.6; I² = 0.0%), BMI (WMD = −0.06 kg/m²; 95% CI: −0.54, 0.42; I² = 0.0%), and WC (WMD = 0.79 cm; 95% CI: −2.83, 0.04; I² = 0.0%).

Conclusions:

CoQ10 supplementation might not improve anthropometric indices. Future well-designed trials are still needed to confirm these results.

Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD.

Effect of Q10 supplementation on body weight and body mass index: A systematic review and meta-analysis of randomized controlled clinical trials

AIMS

This meta-analysis study was carried out to assess the effects of coenzyme Q10 supplementation on body weight and body mass index of patients in randomized controlled clinical trial studies.

MATERIALS AND METHODS

A comprehensive systematic search of literature was performed through ISI web of sciences, PubMed, Scopus and Cochrane library databases up to February 2018 which was supplemented by manual search of the references list of included studies. From a total of 1579 identified articles, only 17 trials with 14 and 14 effect-sizes were included for pooling the effects of co-enzyme Q10 supplementation on body weight and body mass index, respectively.

RESULTS

Results of random-effect size meta-analysis showed that supplementation with coenzyme Q10 had no significant decreasing effects on body weight (WMD: 0.28 kg; 95% CI = -0.91, 1.47; P = 0.64) and BMI (WMD: -0.03; 95% CI = -0.4, 0.34; P = 0.86) of study participants. Subgroup analysis revealed that dosage of Q10 and trial duration could not differ the results of Q10 supplementation.

CONCLUSION

Results of this meta-analysis study failed to show any beneficial effect of coenzyme Q10 supplementation on body weight and BMI of patients in clinical trial studies.

Coenzyme Q10 and Degenerative Disorders Affecting Longevity: An Overview

Longevity is determined by a number of factors, including genetic, environmental and lifestyle factors. A major factor affecting longevity is the development of degenerative disorders such as cardiovascular disease, diabetes, kidney disease and liver disease, particularly where these occur as co-morbidities. In this article, we review the potential role of supplementation with coenzyme Q10 (CoQ10) for the prevention or management of these disorders. Thus, randomised controlled clinical trials have shown supplementation with CoQ10 or CoQ10 plus selenium reduces mortality by approximately 50% in patients with cardiovascular disease, or in the normal elderly population, respectively. Similarly, CoQ10 supplementation improves glycaemic control and vascular dysfunction in type II diabetes, improves renal function in patients with chronic kidney disease, and reduces liver inflammation in patients with non-alcoholic fatty liver disease. The beneficial role of supplemental CoQ10 in the above disorders is considered to result from a combination of its roles in cellular energy generation, as an antioxidant and as an anti-inflammatory agent.

Effect of Coenzyme Q10 on Insulin Resistance in Korean Patients with Prediabetes: A Pilot Single-Center, Randomized, Double-Blind, Placebo-Controlled Study

Introduction

This study aimed to examine whether administration of coenzyme Q10, an antioxidant, improves insulin resistance in patients with prediabetes. The study design was a pilot single-center, randomized, double-blind, placebo-controlled trial.

Methods

This pilot single-center, randomized, double-blind, placebo-controlled trial included a total of 80 adults (aged ≥20 years) with impaired glucose tolerance. After the initial screening visit, subjects were assigned to either the experimental (n = 40) or placebo (n = 40) group via simple randomization. Insulin resistance was represented as the insulin resistance index estimated by homeostasis model assessment (HOMA-IR).

Results

After the 8-week treatment period, the coenzyme group exhibited a significant decrease in the HOMA-IR (P < .001). The free oxygen radical and coenzyme Q10 concentrations were found to correlate significantly (P < .001). However, no significant changes in fasting blood glucose, insulin, and glycated hemoglobin levels were observed in either group. Additionally, no adverse events occurred in either group.

Conclusion

Patients with prediabetes who were administered coenzyme Q10 showed a significant reduction in HOMA-IR values. Therefore, administration of coenzyme Q10 in patients with impaired glucose tolerance may slow the progression from prediabetes to overt diabetes.

The Effects of Coenzyme Q10 Supplementation on Glucose Metabolism, Lipid Profiles, Inflammation, and Oxidative Stress in Patients With Diabetic Nephropathy: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE

Data on the effects of coenzyme Q10 (CoQ10) supplementation on glucose metabolism, lipid profiles, inflammation, and oxidative stress in subjects with diabetic nephropathy (DN) are scarce. This research was done to determine the effects of CoQ10 supplementation on metabolic status in subjects with DN.

METHODS

This randomized double-blind placebo-controlled clinical trial was done in 50 subjects with DN. Participants were randomly assigned into two groups to intake either 100 mg/day CoQ10 supplements (n = 25) or placebo (n = 25) for 12 weeks. Fasting blood samples were obtained at first and after 12-week intervention to quantify metabolic profiles.

RESULTS

After 12 weeks of treatment, compared with the placebo, CoQ10 supplementation resulted in significant decreases in serum insulin levels (-3.4 ± 6.8 vs +0.8 ± 6.4 µIU/mL, p = 0.02), homeostasis model of assessment-estimated insulin resistance (-1.0 ± 2.0 vs +0.2 ± 1.8, p = 0.03), homeostasis model of assessment-estimated B cell function (-12.3 ± 26.3 vs +3.5 ± 23.1, p = 0.02) and HbA1c (-1.1 ± 1.0 vs -0.1 ± 0.2%, p < 0.001), and a significant improvement in quantitative insulin sensitivity check index (+0.009 ± 0.01 vs -0.006 ± 0.01, p = 0.01). In addition, CoQ10 supplementation significantly decreased plasma malondialdehyde (MDA) (-0.6 ± 0.5 vs +0.5 ± 1.0 µmol/L, p < 0.001) and advanced glycation end products levels (AGEs) (-316.4 ± 380.9 vs +318.6 ± 732.0 AU, p < 0.001) compared with the placebo. Supplementation with CoQ10had no significant impacts on fasting plasma glucose (FPG), lipid profiles, and matrix metalloproteinase-2 (MMP-2) compared with the placebo.

CONCLUSIONS

Taken together, our study demonstrated that CoQ10 supplementation for 12 weeks among DN patients had favorable effects on glucose metabolism, MDA, and AGEs levels, but unchanged FPG, lipid profiles, and MMP-2 concentrations.

Mitochondrial CoQ deficiency is a common driver of mitochondrial oxidants and insulin resistance

Insulin resistance in muscle, adipocytes and liver is a gateway to a number of metabolic diseases. Here, we show a selective deficiency in mitochondrial coenzyme Q (CoQ) in insulin-resistant adipose and muscle tissue. This defect was observed in a range of in vitro insulin resistance models and adipose tissue from insulin-resistant humans and was concomitant with lower expression of mevalonate/CoQ biosynthesis pathway proteins in most models. Pharmacologic or genetic manipulations that decreased mitochondrial CoQ triggered mitochondrial oxidants and insulin resistance while CoQ supplementation in either insulin-resistant cell models or mice restored normal insulin sensitivity. Specifically, lowering of mitochondrial CoQ caused insulin resistance in adipocytes as a result of increased superoxide/hydrogen peroxide production via complex II. These data suggest that mitochondrial CoQ is a proximal driver of mitochondrial oxidants and insulin resistance, and that mechanisms that restore mitochondrial CoQ may be effective therapeutic targets for treating insulin resistance.

After we eat, our blood sugar levels increase. To counteract this, the pancreas releases a hormone called insulin. Part of insulin’s effect is to promote the uptake of sugar from the blood into muscle and fat tissue for storage. Under certain conditions, such as obesity, this process can become defective, leading to a condition known as insulin resistance. This condition makes a number of human diseases more likely to develop, including type 2 diabetes. Working out how insulin resistance develops could therefore unveil new treatment strategies for these diseases.

Mitochondria – structures that produce most of a cell’s energy supply – appear to play a role in the development of insulin resistance. Mitochondria convert nutrients such as fats and sugars into molecules called ATP that fuel the many processes required for life. However, ATP production can also generate potentially harmful intermediates often referred to as ‘reactive oxygen species’ or ‘oxidants’. Previous studies have suggested that an increase in the amount of oxidants produced in mitochondria can cause insulin resistance.

Fazakerley et al. therefore set out to identify the reason for increased oxidants in mitochondria, and did so by analysing the levels of proteins and oxidants found in cells grown in the laboratory, and mouse and human tissue samples. This led them to find that concentrations of a molecule called coenzyme Q (CoQ), an essential component of mitochondria that helps to produce ATP, were lower in mitochondria from insulin-resistant fat and muscle tissue. Further experiments suggested a link between the lower levels of CoQ and the higher levels of oxidants in the mitochondria. Replenishing the mitochondria of the lab-grown cells and insulin-resistant mice with CoQ restored ‘normal’ oxidant levels and prevented the development of insulin resistance.

Strategies that aim to increase mitochondria CoQ levels may therefore prevent or reverse insulin resistance. Although CoQ supplements are readily available, swallowing CoQ does not efficiently deliver CoQ to mitochondria in humans, so alternative treatment methods must be found. It is also of interest that statins, common drugs taken by millions of people around the world to lower cholesterol, also lower CoQ and have been reported to increase the risk of developing type 2 diabetes. Further research is therefore needed to investigate whether CoQ might provide the link between statins and type 2 diabetes.

The Effects of Coenzyme Q10 Supplementation on Blood Pressures Among Patients with Metabolic Diseases: A Systematic Review and Meta-analysis of Randomized Controlled Trials

INTRODUCTION

Although several trials have assessed the effect of coenzyme Q10 (CoQ10) supplementation on blood pressures among patients with metabolic diseases, findings are controversial.

AIM

This review of randomized controlled trials (RCTs) was performed to summarize the evidence on the effects of CoQ10 supplementation on blood pressures among patients with metabolic diseases.

METHODS

Randomized-controlled trials (RCTs) published in PubMed, EMBASE, Web of Science and Cochrane Library databases up to 10 August 2017 were searched. Two review authors independently assessed study eligibility, extracted data, and evaluated risk of bias of included studies. Heterogeneity was measured with a Q-test and with I₂ statistics. Data were pooled by using the fix or random-effect model based on the heterogeneity test results and expressed as standardized mean difference (SMD) with 95% confidence interval (CI).

RESULTS

A total of seventeen randomized controlled trials (684 participants) were included. Results showed that CoQ10 supplementation significantly decreased systolic blood pressure (SBP) (SMD - 0.30; 95% CI - 0.52, - 0.08). However, CoQ10 supplementation decreased diastolic blood pressure (DBP), but this was not statistically significant (SMD - 0.08; 95% CI - 0.46, 0.29).

CONCLUSIONS

CoQ10 supplementation may result in reduction in SBP levels, but did not affect DBP levels among patients with metabolic diseases. Additional prospective studies regarding the effect of CoQ10 supplementation on blood pressure in patients with metabolic diseases are necessary.

Effects of coenzyme Q10 on cardiovascular and metabolic biomarkers in overweight and obese patients with type 2 diabetes mellitus: a pooled analysis

BACKGROUND

The potential effects of coenzyme Q10 (CoQ₁₀) supplementation in overweight/obese patients with type 2 diabetes mellitus are not fully established. In this article, we aimed to perform a pooled analysis to investigate the effects of CoQ₁₀ intervention on cardiovascular disease (CVD) risk factors in overweight/obese patients with type 2 diabetes mellitus (T2DM).

METHODS

MEDLINE, Embase, and Cochrane databases were searched for randomized controlled trials that evaluated the changes in CVD risk factors among overweight and obese patients with T2DM following CoQ₁₀ supplementation. Two investigators independently assessed articles for inclusion, extracted data, and assessed risk of bias. Major endpoints were synthesized as weighted mean differences (WMDs) with 95% CIs. Subgroup analyses were performed to check the consistency of effect sizes across groups. Publication bias and sensitivity analysis were also performed.

RESULTS

Fourteen eligible trials with 693 overweight/obese diabetic subjects were included for pooling. CoQ₁₀ interventions significantly reduced fasting blood glucose (FBG; -0.59 mmol/L; 95% CI, -1.05 to -0.12; P=0.01), hemoglobin A1c (HbA1c; -0.28%; 95% CI-0.53 to -0.03; P=0.03), and triglyceride (TG) levels (0.17 mmol/L; 95% CI, -0.32 to -0.03; P=0.02). Subgroup analysis also showed that low-dose consumption of CoQ₁₀ (<200 mg/d) effectively reduces the values of FBG, HbA1c, fasting blood insulin, homeostatic model assessment of insulin resistance, and TG. CoQ₁₀ treatment was well tolerated, and no drug-related adverse reactions were reported.

CONCLUSION

Our findings provide substantial evidence that daily CoQ₁₀ supplementation has beneficial effects on glucose control and lipid management in overweight and obese patients with T2DM.

Effectiveness of Coenzyme Q10 Supplementation for Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the effectiveness and safety of coenzyme Q10 for patients with type 2 diabetes mellitus (T2DM).

METHODS

Data from randomized controlled trials were obtained to assess the effects of coenzyme Q10 versus placebo or western medicine on patients with T2DM. The study's registration number is CRD42018088474. The primary outcomes included glycosylated hemoglobin, fasting blood glucose, and fasting insulin.

RESULT

Thirteen trials involving 765 patients were included. Compared with the control group, coenzyme Q10 may decrease the HbA1c (WMD -0.29; 95% CI -0.54, -0.03; P = 0.03) and the fasting blood glucose (WMD -11.21; 95% CI -18.99, -3.43; P = 0.005). For fasting insulin, there is also not strong evidence that confirms which one is better because there was no statistical difference (WMD -0.48; 95% CI -2.54, 1.57; P = 0.65).

CONCLUSION

Based on current evidence, coenzyme Q10 may assist glycemic control, decrease TG, and improve HDL-C in patients with T2DM.

The effects of coenzyme Q10 supplementation on glucose metabolism and lipid profiles in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Data on the effects of coenzyme Q10 (CoQ10) supplementation on metabolic profiles among subjects with polycystic ovary syndrome (PCOS) are scarce.

OBJECTIVE

This study was carried out to evaluate the effects of CoQ10 supplementation on glucose metabolism and lipid profiles in subjects with PCOS.

DESIGN, PATIENTS AND MEASUREMENTS

This randomized, double-blind, placebo-controlled trial was conducted on 60 women diagnosed with PCOS. Subjects were randomly assigned into two groups to intake either 100 mg CoQ10 supplements (N = 30) or placebo (N = 30) per day for 12 weeks. Markers of insulin metabolism and lipid profiles were assessed at first and 12 weeks after the intervention.

RESULTS

After 12 weeks of intervention, compared to the placebo, subjects who received CoQ10 supplements had significantly decreased fasting plasma glucose (-0·24 ± 0·51 vs +0·01 ± 0·44 mmol/l, P = 0·04), serum insulin concentrations (-7·8 ± 14·4 vs +6·0 ± 15·0 pmol/l, P < 0·001), the homeostasis model of assessment-estimated insulin resistance (-0·3 ± 0·6 vs +0·2 ± 0·6, P = 0·001), the homeostasis model of assessment-estimated B-cell function (-5·4 ± 9·5 vs +4·5 ± 9·9, P < 0·001) and increased the quantitative insulin sensitivity check index (+0·006 ± 0·009 vs -0·006 ± 0·01, P < 0·001). In addition, changes in serum total- (-0·10 ± 0·48 vs +0·19 ± 0·50 mmol/l, P = 0·02) and LDL-cholesterol concentrations (-0·15 ± 0·40 vs +0·14 ± 0·49 mmol/l, P = 0·01) in supplemented women were significantly different from those of women in the placebo group. When we adjusted the analysis for baseline values of biochemical parameters, age and baseline BMI, serum LDL-cholesterol (P = 0·05) became nonsignificant, and other findings did not alter.

CONCLUSIONS

Overall, CoQ10 supplementation for 12 weeks among subjects with PCOS had beneficial effects on glucose metabolism, serum total- and LDL-cholesterol levels.

A meta-analysis of randomized and placebo-controlled clinical trials suggests that coenzyme Q10 at low dose improves glucose and HbA1c levels

The influence of coenzyme Q10 (CoQ10) on blood glucose (BGL) and HbA1c (HL) levels has been previously investigated; however, the results are inconsistent. Therefore, the purpose of this meta-analysis was to determine if CoQ10 could affect BGL and HL levels based on the existing evidence. PubMed, Cochrane Library, Web of Science, Embase, and Scopus databases were searched for randomized clinical trials from September 1, 1956, to March 01, 2016. To calculate pooled overall effects, a random effect model was used. Because of the presence of heterogeneity, the subgroup analysis and the meta-regression were performed. In total, 18 studies (19 study arms) were included in our investigation focusing on the effects of CoQ10 on BGL (17 arms) and HL (12 arms) changes. CoQ10 significantly reduced BGL, whereas it was ineffective in the reduction of the HL. Because of the significant heterogeneity, in the arms involving BGL, we found that lower doses of CoQ10 (<200 mg/d) and a shorter duration of study created a positive effect on BGL. Also, it appeared that CoQ10 could reduce BGL in patients with a glucose level >6 mmol/L as well as in certain ethnic groups. However, because the meta-regression failed to support the subgroup analysis, the result related to the ethnic group should be used only to generate a hypothesis, which is planned in the future. In conclusion, CoQ10 can reduce BGL, particularly when used in lower doses (< 200 mg/d) and when administration was not longer than 12 weeks, in patients both with and without high BGL.

The effect of ubiquinone and combined antioxidant therapy on oxidative stress markers in non-proliferative diabetic retinopathy: A phase IIa, randomized, double-blind, and placebo-controlled study

Objective

To evaluate the effect of ubiquinone (Coenzyme Q10) and combined antioxidant therapy (CAT) on oxidative stress markers in non-proliferative diabetic retinopathy (NPDR) under clinical management.

Study design

In a randomized, double-blind, phase IIa, placebo-controlled, clinical trial, three study groups were formed and administered medications as follows: Group 1, Coenzyme Q10; Group 2, CAT; and Group 3, placebo.

Methods

Serum levels of the products of lipid peroxidation (LPO) and nitrites/nitrates, as markers of oxidative/nitrosative stress, were measured. As antioxidants, the total antioxidant capacity (TAC), catalase activity, and glutathione peroxidase (GPx) activity were measured.

Results

Baseline serum levels of LPO and nitrites/nitrates were significantly elevated in the three groups vs. healthy group (P < 0.0001), while final levels in the Coenzyme Q10 and CAT groups were decreased vs. normal levels (P < 0.0001). The baseline TAC was consumed in the three groups (P < 0.0001), while final results in the Coenzyme Q10 and CAT groups improved (P < 0.0001). Baseline catalase activity was increased in all groups vs. normal values (P < 0.001), while final levels in the Coenzyme Q10 (P < 0.001) and CAT groups (P < 0.0001) were decreased. GPx behaved similarly to catalase and improved in the final results (P < 0.0001).

Discussion

Adjunctive antioxidant treatment for 6 months was effective and safe for improving the oxidative stress in NPDR.

Supplementation of Coenzyme Q10 among Patients with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a major cause of morbidity and mortality with ever increasing prevalence in the United States and worldwide. There is growing body of evidence suggesting that mitochondrial dysfunction secondary to oxidative stress plays a critical role in the pathogenesis of T2DM. Coenzyme Q10 is an important micronutrient acting on the electron transport chain of the mitochondria with two major functions: (1) synthesis of adenosine triphosphate (ATP); and (2) a potent antioxidant. Deficiency in coenzyme Q10 is often seen in patients with T2DM. Whether restoration of coenzyme Q10 will help alleviate oxidative stress, preserve mitochondrial function, and thus improve glycemic control in T2DM is unclear. This article reviews the relationships among oxidative stress, mitochondrial dysfunction, and T2DM and examines the evidence for potential use of coenzyme Q10 as a supplement for the treatment of T2DM.

Effects of coenzyme Q10 supplementation on metabolic profile in diabetes: a systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

CoenzymeQ10 (CoQ10 ), or ubiquinone, is an endogenous enzyme cofactor produced by most human cells. It is a potent antioxidant and is necessary for energy production in mitochondria. Diabetes mellitus is a chronic disease with multiple metabolic abnormalities, principally resulting from the inflammation and oxidative stress associated with mitochondrial dysfunctions. Clinical trials of the effects of supplementary CoQ10 on metabolic control in diabetes have reported inconsistent results. We undertook a systematic review and meta-analysis of randomized controlled trials to assess the effects of CoQ10 supplementation on glycaemic control, lipid profile and blood pressure in patients with diabetes.

METHODS

A systematic search was conducted on MEDLINE, The Cochrane Library, CINAHL, NCCAM, Web of Science, Scopus, ClinicalTrials.gov and historical search of reference lists of relevant articles. The bibliographic databases were searched from inception to February 2015. We included randomized, placebo-controlled trials of CoQ10 in diabetes lasting at least 12 weeks. HbA1c or fasting plasma glucose had to be reported. Primary outcome was glycemic control, and secondary outcomes were lipid profile and blood pressure. Treatment effect was estimated with mean difference.

RESULTS AND DISCUSSION

Seven trials were included in the meta-analysis, involving 356 patients. Neither CoQ10 alone nor CoQ10 plus fenofibrate improved glycemic control. In addition, CoQ10, alone or in combination with fenofibrate, did not alter LDL-C, HDL-C and blood pressure. Triglycerides levels were significantly reduced with CoQ10 (mean difference -0·26 mmol/L, 95% CI -0·05 mmol/L to -0·47 mmol/L, P = 0·02) and CoQ10 plus fenofibrate (mean difference -0·72 mmol/L, 95% CI -0·32 mmol/L to -1·12 mmol/L, P = 0·0004). CoQ10 plus fenofibrate also effectively reduced total cholesterol (mean difference: -0·45 mmol/L, 95% CI -0·06 mmol/L to -0·84 mmol/L, P = 0·02).

WHAT IS NEW AND CONCLUSIONS

CoQ10 supplementation has no beneficial effects on glycemic control, lipid profile or blood pressure in patients with diabetes. However, it may reduce triglycerides levels. Due to limited data availability, well-powered and well-designed randomized controlled trials are needed to clearly determine the effect of CoQ10 on metabolic profile in diabetes. Dosage effects should also be explored.

Strategies for oral delivery and mitochondrial targeting of CoQ10

Coenzyme Q10 (CoQ10), also known as ubiquinone or ubidecarenone, is a powerful, endogenously produced, intracellularly existing lipophilic antioxidant. It combats reactive oxygen species (ROS) known to be responsible for a variety of human pathological conditions. Its target site is the inner mitochondrial membrane (IMM) of each cell. In case of deficiency and/or aging, CoQ10 oral supplementation is warranted. However, CoQ10 has low oral bioavailability due to its lipophilic nature, large molecular weight, regional differences in its gastrointestinal permeability and involvement of multitransporters. Intracellular delivery and mitochondrial target ability issues pose additional hurdles. To maximize CoQ10 delivery to its biopharmaceutical target, numerous approaches have been undertaken. The review summaries the current research on CoQ10 bioavailability and highlights the headways to obtain a satisfactory intracellular and targeted mitochondrial delivery. Unresolved questions and research gaps were identified to bring this promising natural product to the forefront of therapeutic agents for treatment of different pathologies.

Effects of CoQ10 Supplementation on Lipid Profiles and Glycemic Control in Patients with Type 2 Diabetes: a randomized, double blind, placebo-controlled trial

Background

Low grade inflammation and oxidative stress are the key factors in the pathogenesis and development of diabetes and its complications. Coenzyme Q10 (CoQ10) is known as an antioxidant and has a vital role in generation of cellular energy providing. This study was undertaken to evaluate the effects of CoQ10 supplementation on lipid profiles and glycemic controls in patients with diabetes.

Methods

Fifty patients with diabetes were randomly allocated into two groups to receive either 150 mg CoQ10 or placebo daily for 12 weeks. Before and after supplementation, fasting venous blood samples were collected and lipid profiles containing triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) and glycemic indices comprising of fasting plasma glucose (FPG), insulin and hemoglobin A₁C (HbA₁C) were measured. Insulin resistance was calculated using HOMA-IR index.

Results

Forty patients completed the study. After intervention FPG and HbA₁C were significantly lower in the CoQ10 group compared to the placebo group, but there were no significant differences in serum insulin and HOMA-IR between the two groups. Although total cholesterol did not change in the Q10 group after supplementation, triglyceride and HDL-C significantly decreased and LDL-C significantly increased in the CoQ10 group.

Conclusion

The present study showed that treatment with Q10 may improve glycemic control with no favorable effects on lipid profiles in type 2 patients with diabetes.

Trial registration

IRCT registry number: IRCT138806102394N1

Mitochondrial dysfunction in obesity: potential benefit and mechanism of Co-enzyme Q10 supplementation in metabolic syndrome

Co-enzyme Q10 (Co-Q10) is an essential component of the mitochondrial electron transport chain. Most cells are sensitive to co-enzyme Q10 (Co-Q10) deficiency. This deficiency has been implicated in several clinical disorders such as heart failure, hypertension, Parkinson's disease and obesity. The lipid lowering drug statin inhibits conversion of HMG-CoA to mevalonate and lowers plasma Co-Q10 concentrations. However, supplementation with Co-Q10 improves the pathophysiological condition of statin therapy. Recent evidence suggests that Co-Q10 supplementation may be useful for the treatment of obesity, oxidative stress and the inflammatory process in metabolic syndrome. The anti-inflammatory response and lipid metabolizing effect of Co-Q10 is probably mediated by transcriptional regulation of inflammation and lipid metabolism. This paper reviews the evidence showing beneficial role of Co-Q10 supplementation and its potential mechanism of action on contributing factors of metabolic and cardiovascular complications.

The reduced form of coenzyme Q10 improves glycemic control in patients with type 2 diabetes: an open label pilot study

Coenzyme Q10 (CoQ10) provides the energy for vital cellular functions and is known to act as an antioxidant. We conducted an open label study to examine the clinical effects of supplementation of the reduced form of CoQ10, ubiquinol, in addition to conventional glucose-lowering agents in patients with type 2 diabetes. Nine subjects (3 males and 6 females) with type 2 diabetes and receiving conventional medication were recruited. The subjects were assigned to receive an oral dose of 200 mg ubiquinol daily for 12 weeks. The effect of ubiquinol on blood pressure, lipid profile, glycemic control, oxidative stress, and inflammation were examined before and after ubiquinol supplementation. In addition, five healthy volunteers were also assigned to receive an oral dose of 200 mg ubiquinol daily for 4 weeks to examine the effects of ubiquinol on insulin secretion. In patients with diabetes, there were no differences with respect to blood pressure, lipid profile, oxidative stress marker, and inflammatory markers. However, there were significant improvements in glycosylated hemoglobin (53.0 ± 4.3 to 50.5 ± 3.7 mmol/mol, P = 0.01) (7.1 ± 0.4 to 6.8 ± 0.4%, P = 0.03). In healthy volunteers, the insulinogenic index (0.65 ± 0.29 to 1.23 ± 0.56, P = 0.02) and the ratio of proinsulin to insulin were significantly improved (3.4 ± 1.8 to 2.1 ± 0.6, P = 0.03). The results of our study are consistent with the suggestion that the supplementation of ubiquinol in subjects with type 2 diabetes, in addition to conventional antihyperglycemic medications, improves glycemic control by improving insulin secretion without any adverse effects

Hypertension

Hypertension is responsible for roughly one-in-six adult deaths annually in the United States and is associated with five of the top nine causes of death.(1) Ten trillion dollars is the estimated annual cost worldwide of the direct and indirect effects of hypertension.(2,3) In the U.S. alone, costs estimated at almost $74 billion in 2009 placed a huge economic burden on the health care system.(4) The prevalence of hypertension increases with advancing age to the point where more than half of people 60 to 69 years of age and at least three-fourths of those 70 years of age and older are affected.(5) Most individuals with hypertension do not have it adequately controlled.(1,6) Medication noncompliance due to avoidance of side effects is suggested to be a primary factor.(6) The epidemic incidence of hypertension and its significant cost to society indicate that a well-tolerated, cost-effective approach to treatment is urgently needed.

Supplementation of coenzyme Q10 and alpha-tocopherol lowers glycated hemoglobin level and lipid peroxidation in pancreas of diabetic rats

The importance of nutritional supplementation in diabetes remains an unresolved issue. The present study was undertaken to examine the effects of alpha-tocopherol and CoQ(10), powerful antioxidants, on metabolic control and on the pancreatic mitochondria of GK rats, a model of type 2 diabetes. We also evaluated the efficacy of these nutrients in preventing the diabetic pancreatic lesions observed in GK rats. Rats were divided into 4 groups, a control group of diabetic GK rats and 3 groups of GK rats administered with alpha-tocopherol and CoQ(10) alone or both in association, during 8 weeks. Fasting blood glucose levels were not significantly different between the groups, nor were blood glucose levels at 2 hours after a glucose load. HbA1c level was significantly reduced in the group supplemented with both antioxidants. Diabetes induced a decrease in coenzyme Q plasma levels that prevailed after treatment with antioxidants. In addition, the plasma alpha-tocopherol levels were higher after treatment with the antioxidants. An increment in some components of the antioxidant defense system was observed in pancreatic mitochondria of treated GK rats. Moreover, the antioxidants tested either alone or in association failed to prevent the pancreatic lesions in this animal model of type 2 diabetes. In conclusion, our results indicate that CoQ(10) and alpha-tocopherol decrease glycated HbA1c and pancreatic lipid peroxidation. These antioxidants increase some components of the antioxidant defense system but do not prevent pancreatic lesions. Thus, we cannot rule out the potential benefit of antioxidant treatments in type 2 diabetes in the prevention of their complications.

Diabetic neuropathy: mechanisms to management

Neuropathy is the most common and debilitating complication of diabetes and results in pain, decreased motility, and amputation. Diabetic neuropathy encompasses a variety of forms whose impact ranges from discomfort to death. Hyperglycemia induces oxidative stress in diabetic neurons and results in activation of multiple biochemical pathways. These activated pathways are a major source of damage and are potential therapeutic targets in diabetic neuropathy. Though therapies are available to alleviate the symptoms of diabetic neuropathy, few options are available to eliminate the root causes. The immense physical, psychological, and economic cost of diabetic neuropathy underscore the need for causally targeted therapies. This review covers the pathology, epidemiology, biochemical pathways, and prevention of diabetic neuropathy, as well as discusses current symptomatic and causal therapies and novel approaches to identify therapeutic targets.

The role of oral coenzyme Q10 in patients undergoing coronary artery bypass graft surgery

OBJECTIVE

Cardiopulmonary bypass (CPB) is known to induce oxidative stress. Because total antioxidant level is reduced during CPB, the supplementation of an antioxidant might help in attenuating the oxidative stress response. The authors sought to evaluate the efficacy of oral coenzyme Q10, in attenuating the oxidative stress to CPB and altering the clinical outcome in patients undergoing coronary artery bypass graft (CABG) surgery.

DESIGN

A prospective, randomized, single-center clinical study.

SETTING

A cardiothoracic center of a tertiary hospital.

PARTICIPANTS

Thirty patients scheduled for elective CABG surgery.

INTERVENTIONS

The study group (n = 15) received oral coenzyme Q10, 150 to 180 mg/d, for 7 to 10 days preoperatively, whereas the control group (n = 15) did not receive any antioxidant or placebo. The anesthesia technique was standardized in both groups. Blood samples for total antioxidant level, blood glucose level, and clinical outcome parameters up to 24 hours postoperatively were compared.

MEASUREMENTS AND MAIN RESULTS

There was no difference in the antioxidant level between the 2 groups at any point of time. However, in the study group, 24 hours after aortic clamp release, it was significantly higher than baseline (p < 0.05). The blood glucose was significantly lower in the study group at aortic clamp removal and 4 hours after clamp removal as compared with the control group (p = 0.01). The study group had significantly fewer reperfusion arrhythmias, lower total inotropic requirement, mediastinal drainage, blood product requirement, and shorter hospital stays compared with the control group.

CONCLUSION

Oral coenzyme Q10 therapy for 7 to 10 days preoperatively could improve clinical outcome in patients undergoing CABG surgery. A larger study group is recommended for confirmation.

Controlling the sucrose concentration increases Coenzyme Q10 production in fed-batch culture of Agrobacterium tumefaciens

The production yield of Coenzyme Q(10) (CoQ(10)) from the sucrose consumed by Agrobacterium tumefaciens KCCM 10413 decreased, and high levels of exopolysaccharide (EPS) accumulated after switching from batch culture to fed-batch culture. Therefore, we examined the effect of sucrose concentration on the fermentation profile by A. tumefaciens. In the continuous fed-batch culture with the sucrose concentration maintained constantly at 10, 20, 30, and 40 g l(-1), the dry cell weight (DCW), specific CoQ(10) content, CoQ(10) production, and the production yield of CoQ(10) from the sucrose consumed increased, whereas EPS production decreased as maintained sucrose concentration decreased. The pH-stat fed-batch culture system was adapted for CoQ(10) production to minimize the concentration of the carbon source and osmotic stress from sucrose. Using the pH-stat fed-batch culture system, the DCW, specific CoQ(10) content, CoQ(10) production, and the product yield of CoQ(10) from the sucrose consumed increased by 22.6, 13.7, 39.3, and 39.3%, respectively, whereas EPS production decreased by 30.7% compared to those of fed-batch culture in the previous report (Ha SJ, Kim SY, Seo JH, Oh DK, Lee JK, Appl Microbiol Biotechnol, 74:974-980, 2007). The pH-stat fed-batch culture system was scaled up to a pilot scale (300 l), and the CoQ(10) production results obtained (626.5 mg l(-1) of CoQ(10) and 9.25 mg g DCW(-1) of specific CoQ(10) content) were similar to those obtained at the laboratory scale. Thus, an efficient and highly competitive process for microbial CoQ(10) production is available.

Clinical response of myelodysplastic syndromes patients to treatment with coenzyme Q10

The myelodysplastic syndromes (MDS) are a collection of hematopoietic disorders with varying degrees of mono- to trilineage cytopenias and bone marrow dysplasia. In recent years much progress has been made in the treatment of MDS and there are now several therapeutic compounds used with varying levels of success. These compounds typically cause side effects that make them unattractive for treatment of patients in the early stages of MDS. Naturally occurring compounds that are not toxic may provide a means to treat patients in the initial stages of disease. We conducted a pilot study to test the efficacy of coenzyme Q10 (coQ10) in MDS patients with low to intermediate-2 risk disease. A variety of responses were observed in 7 of 29 patients including two trilineage and two cytogenetic responses. Sequencing mitochondrial DNA (mtDNA) from pretreatment bone marrows showed multiple mutations, some resulting in amino acid changes, in 3/5 nonresponders, 1/4 responders and in two control samples. We conclude that coQ10 may be of clinical benefit in a subset of MDS patients, but responders cannot be easily pre-selected on the basis of either the conventional clinical and pathologic characteristics or mtDNA mutations.

Serum coenzyme Q10 concentrations in healthy men supplemented with 30 mg or 100 mg coenzyme Q10 for two months in a randomised controlled study

Serum coenzyme Q10 (Q10) concentrations were evaluated in healthy male volunteers supplemented with 30 mg or 100 mg Q10 or placebo as a single daily dose for two months in a randomised, double-blind, placebo-controlled study. Median baseline serum Q10 concentration in 99 men was 1.26 mg/l (10%, 90% fractiles: 0.82, 1.83). Baseline serum Q10 concentration did not depend on age, while borderline significant positive associations were found for body weight and smoking 1-10 cigarettes/d. Supplementation with 30 mg or 100 mg Q10 resulted in median increases in serum Q10 concentration of 0.55 mg/l and 1.36 mg/l, respectively, compared with a median decrease of 0.23 mg/l with placebo. The changes in the Q10 groups were significantly different from that in the placebo group, and the increase in the 100 mg Q10 group was significantly greater than that in the 30 mg Q10 group. The change in serum Q10 concentration in the Q10 groups did not depend on baseline serum Q10 concentration, age, or body weight.

Coenzyme Q10 improves blood pressure and glycaemic control: a controlled trial in subjects with type 2 diabetes

OBJECTIVE

Our objective was to assess effects of dietary supplementation with coenzyme Q10 (CoQ) on blood pressure and glycaemic control in subjects with type 2 diabetes, and to consider oxidative stress as a potential mechanism for any effects.

SUBJECTS AND DESIGN

Seventy-four subjects with uncomplicated type 2 diabetes and dyslipidaemia were involved in a randomised double blind placebo-controlled 2x2 factorial intervention.

SETTING

The study was performed at the University of Western Australia, Department of Medicine at Royal Perth Hospital, Australia.

INTERVENTIONS

Subjects were randomly assigned to receive an oral dose of 100 mg CoQ twice daily (200 mg/day), 200 mg fenofibrate each morning, both or neither for 12 weeks.

MAIN OUTCOME MEASURES

We report an analysis and discussion of the effects of CoQ on blood pressure, on long-term glycaemic control measured by glycated haemoglobin (HbA(1c)), and on oxidative stress assessed by measurement of plasma F2-isoprostanes.

RESULTS

Fenofibrate did not alter blood pressure, HbA(1c), or plasma F2-isoprostanes. There was a 3-fold increase in plasma CoQ concentration (3.4+/-0.3 micro mol/l, P<0.001) as a result of CoQ supplementation. The main effect of CoQ was to significantly decrease systolic (-6.1+/-2.6 mmHg, P=0.021) and diastolic (-2.9+/-1.4 mmHg, P=0.048) blood pressure and HbA(1c) (-0.37+/-0.17%, P=0.032). Plasma F2-isoprostane concentrations were not altered by CoQ (0.14+/-0.15 nmol/l, P=0.345).

CONCLUSIONS

These results show that CoQ supplementation may improve blood pressure and long-term glycaemic control in subjects with type 2 diabetes, but these improvements were not associated with reduced oxidative stress, as assessed by F2-isoprostanes.

SPONSORSHIP

This study was supported by a grant from the NH&MRC, Australia.

Biochemical functions of coenzyme Q10

Coenzyme Q is well defined as a crucial component of the oxidative phosphorylation process in mitochondria which converts the energy in carbohydrates and fatty acids into ATP to drive cellular machinery and synthesis. New roles for coenzyme Q in other cellular functions are only becoming recognized. The new aspects have developed from the recognition that coenzyme Q can undergo oxidation/reduction reactions in other cell membranes such as lysosomes. Golgi or plasma membranes. In mitochondria and lysosomes, coenzyme Q undergoes reduction/oxidation cycles during which it transfers protons across the membrane to form a proton gradient. The presence of high concentrations of quinol in all membranes provides a basis for antioxidant action either by direct reaction with radicals or by regeneration of tocopherol and ascorbate. Evidence for a function in redox control of cell signaling and gene expression is developing from studies on coenzyme Q stimulation of cell growth, inhibition of apoptosis, control of thiol groups, formation of hydrogen peroxide and control of membrane channels. Deficiency of coenzyme Q has been described based on failure of biosynthesis caused by gene mutation, inhibition of biosynthesis by HMG coA reductase inhibitors (statins) or for unknown reasons in ageing and cancer. Correction of deficiency requires supplementation with higher levels of coenzyme Q than are available in the diet.