The Effect of Dietary Antioxidant Supplementation in Patients with Glaucoma

Abstract

Purpose

Oxidative stress may be a risk factor for glaucoma, and many previous reports have suggested that antioxidants could be a promising treatment. Here, we investigated the effects of a novel supplement containing three food-derived antioxidants (hesperidin, crocetin, and Tamarindus indica) on markers of oxidative stress in patients with glaucoma.

Patients and Methods

This study had a prospective, single arm design. Thirty Japanese glaucoma patients were recruited and given 4 tablets with ample water twice a day for 8 weeks. The treatment was stopped, and the subjects were followed for an additional 8 weeks. We measured biological antioxidant potential (BAP) with a free radical analyzer. We also measured urinary 8-hydroxy-2ʹ-deoxyguanosine (8-OHdG; a marker of oxidative DNA damage). Clinical laboratory data were measured in venous blood samples. Clinical parameters were also recorded. Comparisons used a one-way analysis of variance (ANOVA) followed by Dunnett’s test.

Results

The 8-OHdG level was not reduced. We also divided the patients into groups with high or low oxidative stress. In patients with relatively high oxidative stress, the 8-OHdG level was significantly reduced at weeks 4, 8, 12, and 16 (P < 0.001, P < 0.01, P < 0.01, P < 0.01), and BAP was significantly elevated at weeks 8 and 12 (P = 0.03, P = 0.04). In patients with relatively low oxidative stress, the 8-OHdG level was not significantly reduced during supplement intake but was significantly elevated at weeks 12 and 16 (P =0.03, P = 0.04), while BAP was not significantly elevated.

Conclusion

An 8-week oral course of antioxidant supplementation was effective in patients with a high oxidative stress level. Dietary supplementation could hold promise in the treatment of systemic oxidative stress-related diseases.

Keywords:

• oxidative stress
• supplement
• glaucoma
• 8-OHdG

Abbreviations

ROS, reactive oxygen species; IOP, intraocular pressure; RGC, retinal ganglion cell; OAG, open-angle glaucoma; NTG, normal-tension glaucoma; BAP, biological antioxidant potential; MD, mean deviation; HFA, Humphrey field analyzer; 8-OHdG, 8-hydroxy-2ʹ-deoxyguanosine; NMDA, N-methyl-D-aspartate.

Data Sharing Statement

The authors do not intend to share participant level data.

Ethics Approval and Informed Consent

This study adhered to the Declaration of Helsinki and Clinical Trials Act was approved by the Clinical Research Review Board of Tohoku University (study 2019-6-068), which is certified by the Japanese Ministry of Health, Labor and Welfare. The trial was registered with the UMIN clinical trial registry, number 000032050. Written informed consent was obtained from all subjects before the start of the study.

Acknowledgments

The authors thank Mr. Tim Hilts for editing the language of the manuscript, and Ms. Ruriko Igarashi for providing excellent technical support with oxidative stress measurements. We thank Dr. Hisayo Kubota, Dr. Hideyo Kudo, Dr. Megumi Uematsu, Dr. Marika Sato, and Dr. Naoko Takada for their medical treatment support. We thank Orthmedico Inc. for analyzing the data.

Author Contributions

All authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects or the work.

Disclosure

Professor Toru Nakazawa reports grants from Wakamoto Pharmaceutical Co., Ltd. during the conduct of this study;  grants and personal fees from Santen Pharmaceutical Co., Ltd., Senju Pharmaceutical Co., Ltd., and Topcon Corporation, outside the submitted work;  grants from Nidek Co., Ltd.  This research was supported by Wakamoto Pharmaceutical Co., Ltd. The authors report no other conflicts of interest in this work.