CoQ10

Authors:

Brittany Sood, Michael Keenaghan, Preeti Patel

Findings:

Coenzyme Q10, an endogenous antioxidant essential for cellular energy production, has shown potential to stimulate the immune system and protect the heart from anthracycline-induced cardiotoxicity in some studies. Low blood levels have been observed in patients with certain cancers. However, no peer-reviewed randomized clinical trial supports its use as a cancer treatment, and one observational study suggested antioxidant use (including CoQ10) during chemotherapy may be associated with increased recurrence and decreased survival. Clinical trials investigating CoQ10 for cancer treatment-related fatigue yielded mixed/negative results.

Participants:

Studies involved animal models (rats, mice, monkeys, rabbits, poultry), healthy humans (hepatitis B vaccinated volunteers, 'ordinary subjects'), and patients with various conditions including cancer (breast, myeloma, lymphoma, lung, prostate, pancreas, colon, kidney, head/neck, acute lymphoblastic leukemia, non-Hodgkin lymphoma), cardiovascular disease (heart failure), Huntington's disease, and diabetes. Specific human trials mentioned N=20, N=32, N=59, N=236, N=1134 participants.

Dosage:

Human studies typically used oral doses ranging from 90 to 390 mg/day. Specific trials used 90 mg/day, 300 mg/day (sometimes combined with 300 IU vitamin E), or 30 mg/day (in a combination supplement). Higher doses (300 mg/day and 390 mg/day) were used in follow-up case reports. Doses of 100 mg/day or higher have caused mild insomnia; doses of 300 mg/day for extended periods were associated with elevated liver enzymes (no liver toxicity reported).

Study Quality Assessment:

Includes laboratory, animal (including xenograft), and human/clinical studies. Mentions randomized controlled trials (RCTs), placebo-controlled trials, double-blind (one fatigue study), single-blind (hepatitis B study), open-label nonblinded uncontrolled studies, observational studies (SWOG S0221, N=1134), and case series. Explicitly states 'No report of a randomized clinical trial of coenzyme Q10 as a treatment for cancer has been published in a peer-reviewed scientific journal'. Notes 'important design flaws' in some human studies (e.g., absence of a control group, possible selection bias, multiple confounding variables). Mentions NCI Levels of Evidence analysis applied to human studies. Notes FDA regulation as a dietary supplement (not requiring premarket evaluation unless specific claims made, GMPs apply). Mentions IND application requirement for clinical drug research.

All Effects:

Authors:

Lara Testai

Findings:

This review summarizes CoQ10's clinical applications beyond cardiovascular disease. Evidence supports its use in migraine prophylaxis (Level C evidence mentioned) and suggests benefits for fatigue reduction (in CFS, fibromyalgia, statin myopathy, athletes, MS). Findings are mixed, limited, or inconclusive for neurodegenerative diseases (potential benefit in PD debated, negative in HD/AD), cancer (variable effects on biomarkers/fatigue, potential recurrence reduction in melanoma, no effect on PSA), fertility (improves metabolic/endocrine aspects in PCOS, unclear in male infertility), diabetic neuropathy symptoms, and glaucoma (some positive biomarker/functional changes noted).

Participants:

Review covers studies involving patients with migraine, Chronic Fatigue Syndrome (CFS), fibromyalgia, statin-associated myopathy, Parkinson's Disease (PD), Huntington's Disease (HD), Alzheimer's Disease (AD), Multiple Sclerosis (MS), diabetic neuropathy, glaucoma, various cancers (breast, HCC, prostatic, melanoma), infertility (male and female/PCOS), Dupuytren's Disease, healthy volunteers, and athletes. Sample sizes (N=X) and specific characteristics (e.g., early-stage disease, relapsing-remitting MS, type 2 diabetes) are noted for individual cited studies.

Study Quality Assessment:

This is a review article. Its methodology involved searching PubMed, MEDLINE, Cochrane, Scopus, EMBASE, ClinicalTrials.gov (Jan 1970-Feb 2021) using specified keywords, preferring English-language RCTs but including other designs (open-label, quasi-experimental, pilot trials, meta-analyses). The review cites studies with various designs (RCT, double-blind, placebo-controlled, open-label, systematic review, meta-analysis, etc.) and mentions specific assessment tools (questionnaires like FIS/FIQ/VAS/FSS/BDI, clinical scales like UPDRS/HDRS/HDFCS/TFC/MMSE, biomarker assays like TNFα/GCPR/ATP/hsCRP/CEA/CA 15-3/PSA, electromyography, electroretinogram). The authors acknowledge limitations in the reviewed literature, including frequently undersized RCTs, short durations, low methodological quality, insufficient standardization, lack of dosage titration based on blood levels, and reliance on surrogate endpoints. Declaration of Interest forms were compiled.

All Effects:

Findings:

This article serves as an introduction to systematic reviews and meta-analyses, explaining them as methods to combine and analyze data from different studies on similar topics, particularly RCTs. It outlines the standard procedures, including formulating research questions (PICO), protocol registration, literature searching, study selection, quality assessment (e.g., GRADE, Cochrane risk of bias), data extraction, and statistical analysis (fixed vs. random-effect models, heterogeneity, publication bias). The article stresses that while powerful, these methods require rigorous application and critical interpretation to avoid misleading conclusions due to biases or poor study quality.

Study Quality Assessment:

The text describes methods for conducting systematic reviews and meta-analyses, emphasizing the importance of evaluating study quality. It mentions using randomized controlled trials (RCTs) for higher evidence levels, following guidelines like QUOROM and PRISMA, registering protocols (e.g., PROSPERO), defining PICO, using specific inclusion/exclusion criteria, conducting comprehensive literature searches (e.g., Medline, Embase, CENTRAL), independent study selection by multiple investigators, assessing quality of evidence (e.g., GRADE system, Newcastle-Ottawa Scale for non-randomized studies, Cochrane's 'risk of bias' tool for RCTs covering sequence generation, allocation concealment, blinding, incomplete data, selective reporting, other biases), performing sensitivity analyses, assessing heterogeneity (Forest plot, Cochrane's Q test, I2 statistics), and checking for publication bias (Funnel plot, Begg and Mazumdar's test, Egger's test, trim-and-fill method). It notes that including studies with biases or low quality can yield misleading results.

All Effects:

Findings:

This review discusses Coenzyme Q10's neuroprotective potential in neurological disorders (AD, depression, MS, epilepsy, PD, LHON, ARCA2, SCAR9, stroke) based on its antioxidant, anti-inflammatory, energy production, and mitochondria-stabilizing roles. Reviewed studies suggest CoQ10 can reduce oxidative stress, inflammation, apoptosis, and improve outcomes, though some effects are dose-dependent or controversial, warranting further research. CoQ10 deficiency is linked to the pathogenesis of these conditions.

Participants:

Review article summarizing studies on both Animal models (rats, mice) and Human models (adults, women and men, patients with AD, PD, MS, epilepsy, depression, stroke, LHON, ARCA2, SCAR9, BD, CAD).

Dosage:

Review covers a wide range of dosages from multiple studies: Animal models used doses like 10 mg/kg, 50 mg/kg, 200 mg/kg, up to 1600 mg/kg via various routes (i.p., p.o., gavage, drinking water) for durations from minutes to months. Human studies reviewed used doses such as 60-150 mg/day, 90-200 mg/day, 300 mg/day, 400 mg/day, 500 mg/day, 1200 mg/day, and 500 mg twice daily, for durations from weeks to over a year. Safety noted up to 1200 mg/day; some effects are dose-dependent.

Study Quality Assessment:

Systematic review article searching Scopus, Google Scholar, Web of Science, PubMed/MEDLINE up to Dec 2020. References specific study designs like 'randomized clinical trials', 'double-blinded, placebo-controlled trial'. Mentions specific methods (e.g., HPLC, field potential recording) and models (e.g., APP/PS1 mouse, MPTP model, kainate model). Acknowledges controversial findings, dose-dependency, and areas needing more research. Funding source mentioned (Hamadan University of Medical Sciences). Published in open-access journal 'Front Neurosci'.

All Effects:

Findings:

Supplementation with CoQ10 significantly increased plasma CoQ10 levels compared to placebo over 24 weeks. However, there were no significant differences between the CoQ10 and placebo groups in self-reported fatigue, depression, or quality of life scores at 24 weeks.

Participants:

N=236 women with newly diagnosed breast cancer (pathologic stage 0: 91%; stage 1: 8%; stage II: 1%) and planned adjuvant chemotherapy. Age range 28-85 years. Ethnicity: white (87%), black (11%), Hispanic (2%).

Dosage:

300 mg CoQ10 (or placebo) combined with 300 IU vitamin E, divided into 3 daily doses, for 24 weeks.

Study Quality Assessment:

Randomized, double-blind, placebo-controlled study. N=236 enrolled. Methods included blood tests, QOL measures (Profile of Mood States-Fatigue, Functional Assessment of Chronic Illness Therapy-Fatigue, Functional Assessment of Cancer Therapy-Breast Cancer, Center for Epidemiologic Studies-Depression scale), plasma CoQ10 and vitamin E level measurements, and mixed-effects models for analysis. Trial registration: ClinicalTrials.gov NCT00096356.

All Effects: