Clinical Trial of the Effects of Coenzyme Q10 Supplementation on Biomarkers of Inflammation and Oxidative Stress in Diabetic Hemodialysis Patients

The Effects of Curcumin Administration on Carotid Intima-Media Thickness and Pulse Wave Velocity in Diabetic Hemodialysis Patients: A Randomized, Double-Blinded, Placebo-Controlled Trial

Background

Prior studies have reported that curcumin is inversely associated with reduced markers of atherosclerosis risk, including carotid intima-media thickness (CIMT). This study was designed to assess the effects of curcumin on CIMT and pulse wave velocity (PWV) in diabetic hemodialysis (HD) patients.

Methods

This randomized, double-blinded, placebo-controlled trial was conducted on 39 diabetic HD patients. People were assigned to receive curcumin or placebo (starch) for 24 weeks. Individuals in the curcumin group (n = 26) received 80 mg/day. CIMT and PWV levels were taken at baseline and after 24 weeks of intervention.

Results

After 24 weeks of intervention, curcumin intake did not affect mean levels of left (P = 0.83) and right (P = 0.47) CIMT and maximum levels of left (P = 0.84) and right (P = 0.11) CIMT, and PWV (P = 0.12) compared to the placebo. Furthermore, within-group difference demonstrated a significant reduction in mean levels of PWV (P = 0.01) in the curcumin group. We did not observe any significant change in C-reactive protein (CRP) concentrations after curcumin intake (P = 0.69).

Conclusions

Curcumin intake did not affect mean levels of left and right CIMT and maximum levels of left and right CIMT, PWV, and CRP levels compared to the placebo. Additionally, within-group difference demonstrated a significant reduction in mean levels of PWV in the curcumin group.This trial was registered at www.irct.ir as http://www.irct.ir: IRCT20200527047584N1.

Antioxidants for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for cardiovascular disease (CVD) and death. Increased oxidative stress in people with CKD has been implicated as a potential causative factor. Antioxidant therapy decreases oxidative stress and may consequently reduce cardiovascular morbidity and death in people with CKD. This is an update of a Cochrane review first published in 2012.

OBJECTIVES

To examine the benefits and harms of antioxidant therapy on death and cardiovascular and kidney endpoints in adults with CKD stages 3 to 5, patients undergoing dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies until 15 November 2022 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials investigating the use of antioxidants, compared with placebo, usual or standard care, no treatment, or other antioxidants, for adults with CKD on cardiovascular and kidney endpoints.

DATA COLLECTION AND ANALYSIS

Titles and abstracts were screened independently by two authors who also performed data extraction using standardised forms. Results were pooled using random effects models and expressed as risk ratios (RR) or mean difference (MD) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 95 studies (10,468 randomised patients) that evaluated antioxidant therapy in adults with non-dialysis-dependent CKD (31 studies, 5342 patients), dialysis-dependent CKD (41 studies, 3444 patients) and kidney transplant recipients (21 studies, 1529 patients). Two studies enrolled dialysis and non-dialysis patients (153 patients). Twenty-one studies assessed the effects of vitamin antioxidants, and 74 assessed the effects of non-vitamin antioxidants. Overall, the quality of included studies was moderate to low or very low due to unclear or high risk of bias for randomisation, allocation concealment, blinding, and loss to follow-up. Compared with placebo, usual care, or no treatment, antioxidant therapy may have little or no effect on cardiovascular death (8 studies, 3813 patients: RR 0.94, 95% CI 0.64 to 1.40; I² = 33%; low certainty of evidence) and probably has little to no effect on death (any cause) (45 studies, 7530 patients: RR 0.95, 95% CI 0.82 to 1.11; I² = 0%; moderate certainty of evidence), CVD (16 studies, 4768 patients: RR 0.79, 95% CI 0.63 to 0.99; I² = 23%; moderate certainty of evidence), or loss of kidney transplant (graft loss) (11 studies, 1053 patients: RR 0.88, 95% CI 0.67 to 1.17; I² = 0%; moderate certainty of evidence). Compared with placebo, usual care, or no treatment, antioxidants had little to no effect on the slope of urinary albumin/creatinine ratio (change in UACR) (7 studies, 1286 patients: MD -0.04 mg/mmol, 95% CI -0.55 to 0.47; I² = 37%; very low certainty of evidence) but the evidence is very uncertain. Antioxidants probably reduced the progression to kidney failure (10 studies, 3201 patients: RR 0.65, 95% CI 0.41 to 1.02; I² = 41%; moderate certainty of evidence), may improve the slope of estimated glomerular filtration rate (change in eGFR) (28 studies, 4128 patients: MD 3.65 mL/min/1.73 m², 95% CI 2.81 to 4.50; I² = 99%; low certainty of evidence), but had uncertain effects on the slope of serum creatinine (change in SCr) (16 studies, 3180 patients: MD -13.35 µmol/L, 95% CI -23.49 to -3.23; I² = 98%; very low certainty of evidence). Possible safety concerns are an observed increase in the risk of infection (14 studies, 3697 patients: RR 1.30, 95% CI 1.14 to 1.50; I² = 3%; moderate certainty of evidence) and heart failure (6 studies, 3733 patients: RR 1.40, 95% CI 1.11 to 1.75; I² = 0; moderate certainty of evidence) among antioxidant users. Results of studies with a low risk of bias or longer follow-ups generally were comparable to the main analyses.

AUTHORS' CONCLUSIONS

We found no evidence that antioxidants reduced death or improved kidney transplant outcomes or proteinuria in patients with CKD. Antioxidants likely reduce cardiovascular events and progression to kidney failure and may improve kidney function. Possible concerns are an increased risk of infections and heart failure among antioxidant users. However, most studies were of suboptimal quality and had limited follow-up, and few included people undergoing dialysis or kidney transplant recipients. Furthermore, the large heterogeneity in interventions hampers drawing conclusions on the efficacy and safety of individual agents.

Diabetic Nephropathy: Significance of Determining Oxidative Stress and Opportunities for Antioxidant Therapies

Diabetes mellitus (DM) belongs to the category of socially significant diseases with epidemic rates of increases in prevalence. Diabetic nephropathy (DN) is a specific kind of kidney damage that occurs in 40% of patients with DM and is considered a serious complication of DM. Most modern methods for treatments aimed at slowing down the progression of DN have side effects and do not produce unambiguous positive results in the long term. This fact has encouraged researchers to search for additional or alternative treatment methods. Hyperglycemia has a negative effect on renal structures due to a number of factors, including the activation of the polyol and hexosamine glucose metabolism pathways, the activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, the accumulation of advanced glycation end products and increases in the insulin resistance and endothelial dysfunction of tissues. The above mechanisms cause the development of oxidative stress (OS) reactions and mitochondrial dysfunction, which in turn contribute to the development and progression of DN. Modern antioxidant therapies for DN involve various phytochemicals (food antioxidants, resveratrol, curcumin, alpha-lipoic acid preparations, etc.), which are widely used not only for the treatment of diabetes but also other systemic diseases. It has also been suggested that therapeutic approaches that target the source of reactive oxygen species in DN may have certain advantages in terms of nephroprotection from OS. This review describes the significance of studies on OS biomarkers in the pathogenesis of DN and analyzes various approaches to reducing the intensity of OS in the prevention and treatment of DN.

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.

Discovering the Potential Value of Coenzyme Q10 in Oxidative Stress: Enlightenment From a Synthesis of Clinical Evidence Based on Various Population

Background: Oxidative stress (OS) is associated with ferroptosis. Coenzyme Q10 (CoQ10), as an adjuvant treatment, has shown to be beneficial against OS. However, the efficacy of CoQ10 as a therapeutic agent against OS has not been promptly updated and systematically investigated.

Methods: A systematic literature search was performed using the Medline, EMBASE, Web of science, Cochrane Central Register of Controlled Trials, CNKI, CBM, Science direct and clinical trial. gov to identify randomized clinical trials evaluating the efficacy of CoQ10 supplementation on OS parameters. Standard mean differences and 95% confidence intervals were calculated for net changes in OS parameters using a random-effects model.

Results: Twenty-one randomized clinical studies met the eligibility criteria to be included in the meta-analysis. Overall, CoQ10 supplementation increased the levels of antioxidant enzymes [including superoxide dismutase (SOD) (SMD = 0.63; 95% CI: 0.38 to 0.88; p < 0.001), catalase (CAT) (SMD = 0.44; 95% CI:0.16 to 0.72; p = 0.002)] significantly and the levels of malondialdehyde (MDA) (SMD = -0.68; 95% CI: 0.93 to -0.43; p < 0.001) was decreased considerably. However, significant associations were not observed between this supplement and total antioxidant capacity (TAC), glutathione peroxidase (GPx) activity.

Conclusion: CoQ10 can improve OS as indicated by statistical significance in CAT and MDA concentrations, as well as SOD activity. Future studies focusing on long-term results and specific valuation of OS parameters are required to confirm the efficacy of CoQ10 on OS. We also believe that with the further research on ferroptosis, CoQ10 will gain more attention.

Systematic Review Registration: [https://inplasy.com/], identifier [INPLASY2021120123].

Effects of Coenzyme Q10 Supplementation on Biomarkers of Oxidative Stress in Adults: A GRADE-Assessed Systematic Review and Updated Meta-Analysis of Randomized Controlled Trials

Evidence shows that exogenous CoQ10 supplementation may potentially attenuate oxidative stress status. However, its effective dose and evidence certainty require further evaluation in the general population via more updated randomized controlled trials (RCTs). Databases (PubMed, Embase and Cochrane Library) were searched up to 30 March 2022. Evidence certainty was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Thirty-four RCTs containing 2012 participants were included in this review. Pooled effects of significant increase in total antioxidant capacity (TAC) (standardized mean difference: 1.83, 95%CI: [1.07, 2.59], p < 0.001) and significant reduction in malondialdehyde (MDA) concentrations (−0.77, [−1.06, −0.47], p < 0.001) were shown after CoQ10 supplementation compared to placebo. However, we could not determine that there was a significant increase in circulating superoxide dismutase (SOD) levels yet (0.47, [0.00, 0.94], p = 0.05). Subgroup analyses implied that CoQ10 supplementation was more beneficial to people with coronary artery disease or type 2 diabetes. Additionally, taking 100−150 mg/day CoQ10 supplement had better benefits for the levels of TAC, MDA and SOD (all p < 0.01). These results to a statistically significant extent lent support to the efficacy and optimal dose of CoQ10 supplementation on attenuating oxidative stress status in adults.

The effects of coenzyme Q10 supplementation on metabolic profiles and parameters of mental health in women with polycystic ovary syndrome

OBJECTIVE

Evaluating the impact of coenzyme Q10 (CoQ10) supplementation on hormonal indices, mental health, and biomarkers of inflammatory responses and oxidative stress among female patients suffering from polycystic ovary syndrome (PCOS).

METHODS

The present double-blinded, placebo-controlled randomized clinical trial consisted of 55 PCOS women (aged 18-40 years old), who were randomized into groups receiving 100 mg/day of CoQ10 (28 cases) or placebo (27 cases) for 12 weeks.

RESULTS

The supplementation of CoQ10 decreased significantly the scores of Beck Depression Inventory (BDI) (p = .03) and Beck Anxiety Inventory (BAI) (p = .01) and high-sensitivity C-reactive protein (hs-CRP) level (p = .005) when comparing with the placebo group. Moreover, CoQ10 group exhibited a significant drop in total testosterone (p = .004), dehydroepiandrosterone sulfate (DHEAS) (p < .001), hirsutism (p = .002) and malondialdehyde (MDA) (p = .001) levels in the serum, and a significant rise in sex hormone-binding globulin (SHBG) (p < .001) and total antioxidant capacity (TAC) (p < .001) levels in the serum than the placebo group.

CONCLUSIONS

12-week supplementation of CoQ10 to PCOS women showed beneficial impact on BDI, BAI, hs-CRP, total testosterone, DHEAS, hirsutism, SHBG, TAC and MDA levels.

Ubisol Coenzyme Q10 promotes mitochondrial biogenesis in HT22 cells challenged by glutamate

Glutamate-induced excitotoxicity is a well-recognized cause of neuronal cell death. Nutritional supplementation with Coenzyme Q10 (CoQ10) has been previously demonstrated to serve neuro-protective effects against glutamate-induced excitotoxicity. The aim of the present study was to determine whether the protective effect of CoQ10 against glutamate toxicity could be attributed to stimulating mitochondrial biogenesis. Mouse hippocampal neuronal HT22 cells were incubated with glutamate with or without ubisol Q10. The results revealed that glutamate significantly decreased levels of mitochondrial biogenesis related proteins, including peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α and nuclear respiratory factor (NRF)2. Additionally, glutamate reduced mitochondrial biogenesis, as determined using a mitochondrial biogenesis kit. Pretreatment with CoQ10 prevented decreases in phosphorylated (p)-Akt, p-cAMP response element-binding protein, PGC-1α, NRF2 and mitochondrial transcription factor A, increasing mitochondrial biogenesis. Taken together, the results described a novel mechanism of CoQ10-induced neuroprotection and indicated a central role for mitochondrial biogenesis in protecting against glutamate-induced excitotoxicity.

Does Coenzyme Q10 Supplementation Improve Testicular Function and Spermatogenesis in Male Mice with Chronic Kidney Disease?

Simple Summary

Chronic kidney disease (CKD) is found to be linked to elevated apoptosis, oxidative stress and inflammation. Moreover, lower testosterone, poorer sperm quality and lower reproductive function have also been observed. Coenzyme Q10 (CoQ10), a widely used antioxidant involved in mitochondrial energy production, is indispensable for maintaining the efficient energy system of spermatozoa and protecting their membranes from lipid peroxidation, yet there are few studies focusing on the effects of CoQ10 on CKD-induced male infertility. This study suggests that CoQ10 increases testosterone levels and improves spermatogenesis in CKD mice.

Abstract

The aim of the study was to examine the potential effects of coenzyme Q10 (CoQ10) on reproductive function in a chronic kidney disease (CKD) mouse model. Nine-week-old mice were randomly assigned to two groups: sham surgery (n = 18) and CKD surgery (n = 18). After surgery, the study groups received CoQ10 (10 mg/kg body weight dissolved in corn oil by oral gavage) or corn oil as a vehicle daily for 8 weeks. The groups that underwent 5/6 nephrectomy developed significant elevations of serum BUN and creatinine levels. The CoQ10 treatment significantly increased the serum and testicular CoQ10 levels and alleviated the poor semen quality from incomplete spermatogenesis. The testosterone concentration, in addition to the protein expression of enzymes related to testosterone biosynthesis, was also elevated, and the CKD-induced decrease in antioxidant activity in the testes was significantly ameliorated. The results suggest that CoQ10 could act against CKD-induced testicular dysfunction through improvements in the sperm function, testicular morphology, testosterone levels and related biosynthesis pathways, in addition to antioxidant activity.

Impact of coenzyme Q10 on inflammatory biomarkers and its role in future therapeutic strategies

Coenzyme Q (CoQ) is an important component of the mitochondrial electron transport chain. The finding that multiple chronic diseases show lower levels of CoQ10 has led to the possibility that CoQ10 supplementation could be an effective approach to ameliorate or prevent disease progression. In this review, we discuss the state of the art regarding the role of CoQ10 in health and disease and describe the latest clinical studies which have tested the effects of CoQ10 supplementation in inflammatory diseases. The results of these studies indicate that individuals suffering from inflammation-related diseases show improvement under the CoQ10 supplementation protocol. However, these results have been inconsistent, leading to the need for additional studies at the preclinical and clinical levels, involving a greater number of subjects and different treatment regimes.

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.

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.

Effects of coenzyme Q10 on endothelial and cardiac function in patients undergoing haemodialysis: study protocol for a pilot randomised controlled trial

INTRODUCTION

Endothelial and cardiac dysfunction are highly prevalent and are associated with cardiovascular morbidity and mortality among patients undergoing dialysis. For patients undergoing dialysis, no study has explored the effect of supplementation of coenzyme Q10 (CoQ10) on endothelial function. To our best of knowledge, only two small sample studies focused on the efficacy of supplementation of CoQ10 on cardiac function. However, the effect of CoQ10 supplementation on cardiac function remains uncertain in patients who undergo haemodialysis. The aim of this study is to explore whether CoQ10 supplementation can improve endothelial and cardiac function in patients undergoing haemodialysis.

METHODS AND ANALYSIS

This is a pilot randomised controlled study. Eligible patients undergoing haemodialysis in our haemodialysis centre will be randomly allocated to the CoQ10 and control groups. The follow-up time is 12 months. The primary outcome is to assess the change of brachial artery endothelial-dependent flow-mediated dilation, left ventricular systolic function, diastolic function and Myocardial Performance Index at 12 months from baseline. Secondary outcomes are death or hospitalisation due to cardiovascular events, all-cause mortality, change of CoQ10 concentration, the ratio of ubiquinol to ubiquinone, the change of oxidative stress markers (including malondialdehyde and 8-hydroxy-deoxyguanosine) and Left Ventricular Mass Index.

ETHICS AND DISSEMINATION

Risks associated with CoQ10 are minor, even at doses as high as 1800 mg according to previous studies. The trial has received ethics approval from the Medical Ethics Committee for Clinical Trials of Drugs, the 306th Hospital of Chinese PLA. The results of the study are expected to be published in a peer-reviewed journal and presented at academic conferences.

TRIAL REGISTRATION NUMBER

ChiCTR1900022258.

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.

Endothelial dysfunction and inflammatory biomarkers as a response factor of concurrent coenzyme Q10 add-on metformin in patients with type 2 diabetes mellitus

OBJECTIVES

The objective of the study was to evaluate the effect of metformin alone or in combination with coenzyme Q10 (CoQ10) on inflammatory changes and endothelial dysfunction in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

A total numbers of 54 patients with T2DM compared to 30 healthy subjects were divided into three groups: Group A (n = 30): healthy subjects without any medications; Group B (n = 24): T2DM patients treated with metformin 1 g/day; and Group C (n = 30): T2DM patients treated with metformin 1 g/day plus CoQ10, 300 mg/day. The duration of the study was 8 weeks. Fasting blood glucose, glycated hemoglobin, lipid profile, blood pressure variables, fasting insulin, insulin resistance, homeostatic model assessment of insulin resistance, vascular cell adhesion molecule 1 (VCAM-1), and E-selectin were measured before and after therapy.

RESULTS

Metformin and/or CoQ10 therapy illustrated an insignificant effect on the fody mass index. This combination produced a significant improvement of metabolic changes in patients with T2DM (P < 0.01). sVCAM-1 serum level was decreased significantly after the initiation of metformin and/or CoQ10 therapy compared to the baseline P < 0.05. E-selectin was declined significantly following metformin monotherapy and after metformin plus CoQ10 therapy (P = 0.0001).

CONCLUSION

CoQ10 add-on metformin therapy improves endothelial dysfunction and inflammatory changes in patients with T2DM alongside with amelioration of metabolic profile.

The effect of coenzyme Q10 supplementation on oxidative stress: A systematic review and meta-analysis of randomized controlled clinical trials

Some evidence exists in supporting the beneficial effects of coenzyme Q10 (CoQ10) on oxidative stress. Since the findings of studies over the impact of CoQ10 supplementation on oxidative stress are contradictory, this study was conducted. The aim was to evaluate CoQ10 supplementation effect on total antioxidant capacity (TAC), malondialdehyde (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) levels using data collected from randomized controlled trials (RCTs). Several databases including PubMed, Web of Science, Google Scholar, and Scopus were comprehensively searched up to 23 January 2019 to identify RCTs. A random-effects model, standardized mean difference (SMD), and 95% confidence interval (CI) were applied for data analysis. According to the meta-analysis results on 19 eligible studies, CoQ10 increased the levels of TAC (SMD = 1.29; 95% CI = 0.35-2.23; p = .007), GPX (SMD = 0.45; 95% CI = 0.17-0.74; p = .002), SOD (SMD = 0.63; 95% CI = 0.29-0.97; p < .0001), and CAT (SMD = 1.67; 95% CI = 0.29-3.10; p = .018) significantly. This supplementation also caused a significant reduction in MDA levels (SMD = -1.12; 95% CI = -1.58 to -0.65; p < .0001). However, the results of SOD and CAT should be stated carefully due to the publication bias. In conclusion, this research indicated that CoQ10 supplementation had beneficial effects on oxidative stress markers. However, further studies are needed to confirm these findings.

Characteristics of Selected Antioxidative and Bioactive Compounds in Meat and Animal Origin Products

Meat and meat products have a high nutritional value. Besides major components, meat is rich in bioactive components, primarily taurine, l-carnitine, choline, alpha-lipoic acid, conjugated linoleic acid, glutathione, creatine, coenzyme Q10 and bioactive peptides. Many studies have reported their antioxidant and health-promoting properties connected with their lipid-lowering, antihypertensive, anti-inflammatory, immunomodulatory activity and protecting the organism against oxidative stress. The antioxidant activity of meat components results, among others, from the capability of scavenging reactive oxygen and nitrogen species, forming complexes with metal ions and protecting cells against damage. This review is focused to gather accurate information about meat components with antioxidant and biological activity.