Tabriz University of Medical Sciences Advanced Pharmaceutical Bulletin 2228-5881 16 1 2026 05 19 The Effects of Coenzyme Q10 Supplementation on the Contrast Sensitivity Score, Biomarkers of Oxidative Stress, Inflammation, and β-Secretase Activity in the Blood and the Correlation Among these Factors in Diabetic Retinopathy Patients; Clinical Trial 189 205 10.34172/apb.46420 EN Mohammad Hossein Sharif https://orcid.org/0000-0002-2172-3043 Fatemeh Javadian Sarraf Ehsan Sharifipour Masumeh Zamanlu https://orcid.org/0000-0002-6326-8448 Parsa Gholipour Alireza Soltanian Siamak Shahidi Abdolrahman Sarihi https://orcid.org/0000-0002-2452-5210 Journal Article 10.34172/apb.46420 2025 09 21 2026 03 20 Introduction: Diabetic retinopathy (DR), the most common complication of diabetes and is recognized as the leading cause of visual impairment. Coenzyme Q10 (CoQ10) is a nonenzymatic antioxidant that restores other antioxidants, and its benefits in reducing inflammation in various disorders have been demonstrated. In this context, the primary aim of this survey was to evaluate the beneficial effects of CoQ10 on oxidative status, pro-inflammatory cytokines, β-secretase (BACE1) activity, and contrast sensitivity (CS) score in DR patients, and more importantly, the correlation of BACE1 with oxidative status and inflammatory parameters. Methods: 74 DR patients (38 females and 36 males) were divided into two groups as placebo and CoQ10. The treatment process took 12 weeks. One group received 200mg cellulose acetate as a placebo, and the other group received 200 mg CoQ10. Before and after finishing the treatment process, 10ml of venous blood samples were taken from all participants to measure changes in CoQ10, Total Antioxidant Capacity (TAC), Total Oxidant Status (TOS), Glutathione (GSH), Malondialdehyde (MDA), Catalase activity (CAT), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and BACE1 activity in the serum. Moreover, the CS scores were also evaluated. Results: all the measured oxidative stress and inflammatory parameters, BACE1 activity, and also CS score were attenuated after treatment with CoQ10 in the DR patients (P<0.05). Moreover, after evaluating the correlation between BACE1 activity with oxidative stress and inflammatory paradigms, it was shown that there were significant correlations. Conclusion: CoQ10 supplementation increases CS score in DR patients, which can be due to a decrease in BACE1 activity. Furthermore, the reduction in BACE1 activity in DR patients was partly related to the enhancement of the antioxidant defense system and a reduction in inflammation, as there was a high correlation between BACE1 activity and these parameters.