Effects of coenzyme Q10 supplementation on inflammation, angiogenesis, and oxidative stress in breast cancer patients: a systematic review and meta-analysis of randomized controlled- trials.

BACKGROUND/OBJECTIVE Systemic inflammation and oxidative stress (OS) are associated with breast cancer. CoQ10 as an adjuvant treatment with conventional anti-cancer chemotherapy has been demonstrated to help in the inflammatory process and OS. This systematic review and meta-analysis of randomized clinical trials (RCTs) aimed to evaluate the efficacy of CoQ10 supplementation on levels of inflammatory markers, OS parameters, and matrix metalloproteinases/tissue inhibitor of metalloproteinases (MMPs/TIMPs) in patients with breast cancer. METHODS A systematic literature search was carried out using electronic databases, including PubMed, Web of Science, Scopus, Google Scholar, and Embase, up to December 2020 to identify eligible RCTs evaluating the effect of CoQ10 supplementation on OS biomarkers, inflammatory cytokines, and MMPs/TIMPs. From 827 potential reports, 5 eligible studies consisting of 9 trials were finally included in the current meta-analysis. Quality assessment and heterogeneity tests of the selected trials were performed using the PRISMA checklist protocol and the I2 statistic, respectively. Fixed and random-effects models were assessed based on the heterogeneity tests, and pooled data were determined as the standardized mean difference (SMD) with a 95% confidence interval (CI). RESULTS Our meta-analysis of the pooled findings for inflammatory biomarkers of OS and MMPs showed that CoQ10 supplementation (100 mg/day for 45-90 days) significantly decreased the levels of VEGF [SMD: - 1.88, 95% CI: (- 2. 62 to - 1.13); I2 = 93.1%, p < 0.001], IL-8 [SMD: - 2.24, 95% CI: (- 2.68 to - 1.8); I2 = 79.6%, p = 0.001], MMP-2 [SMD: - 1.49, 95% CI: (- 1.85 to - 1.14); I2 = 76.3%, p = 0.005] and MMP-9 [SMD: - 1.58, 95% CI: (- 1.97 to - 1.19); I2 = 79.6%, p = 0.002], but no significant difference was observed between CoQ10 supplementation and control group on TNF-α [SMD: - 2.30, 95% CI: (- 2.50 to - 2.11); I2 = 21.8%, p = 0.280], IL-6 [SMD: - 1.56, 95% CI: (- 1.73 to - 1.39); I2 = 0.0%, p = 0.683], IL-1β [SMD: - 3.34, 95% CI: (- 3.58 to - 3.11); I2 = 0.0%, p = 0.561], catalase (CAT) [SMD: 1.40, 95% CI: (1.15 to 1.65); I2 = 0.0%, p = 0.598], superoxide dismutase (SOD) [SMD: 2.42, 95% CI: (2.12 to 2.71); I2 = 0.0%, p = 0.986], glutathione peroxidase (GPx) [SMD: 2.80, 95% CI: (2.49 to 3.11); I2 = 0.0%, p = 0.543]], glutathione (GSH) [SMD: 4.71, 95% CI: (4.26 to 5.16); I2 = 6.1%, p = 0.302] and thiobarbituric acid reactive substances (TBARS) [SMD: - 3.20, 95% CI: (- 3.53 to - 2.86); I2 = 29.7%, p = 0.233]. CONCLUSION Overall, the findings showed that CoQ10 supplementation reduced some of the important markers of inflammation and MMPs in patients with breast cancer. However, further studies with controlled trials for other types of cancer are needed to better understand and confirm the effect of CoQ10 on tumor therapy.