The Association of Serum Iron-Binding Proteins and the Antioxidant Parameter Levels in Age-Related Macular Degeneration

ABSTRACT

Purpose: Age-related macular degeneration (AMD) is the leading cause of the irreversible central visual loss among the elderly in the developed countries. Iron is considered a potent generator of the oxidative damage whose levels increase with age, potentially exacerbating the age-related diseases. The aim of this study was to assess the serum values of iron, and iron-binding proteins (transferrin, ferritin, and haptoglobin) in patients with AMD along with the parameters of the antioxidant defense: superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase, and total antioxidant status (TAS), in order to analyze the possible impact of iron and iron-binding proteins to the development of oxidative stress in AMD patients, and the association of the selected parameters with the AMD. In addition, the aim was to examine the gender differences and calculate the cutoff points of tested parameters that could be associated with AMD.

Material and methods: A cross-sectional study included 55 AMD patients aged 71.7 ± 7.36 years and 65 aged-matched control subjects aged 70.25 ± 6.46 years.

Results: Significantly lower ferritin (P = 0.025), SOD (P = 0.026), GPx (P = 0.019), and TAS (P < 0.004) values were found in patients with AMD compared to the controls (P < 0.05). Significant association of GPx < 27 U/gHb (odds ratio [OR]: 1.13; 95% confidence interval [CI] 0.78–2.10; P = 0.049), TAS < 1.25 mmol/L (OR: 5.77; 95% CI 0.98–367.0; P < 0.000), ferritin < 84.8 pg/mL (OR: 2.52; 95% CI 1.37–4.62; P = 0.002), and haptoglobin<1.51 g/L (OR: 1.94; 95% CI 1.05–3.56; P = 0.031) was found with the AMD. According to receiver operating characteristic curve analysis, ferritin concentration <84.8 pg/L, GPx < 27 U/gHb, and TAS < 1.25 mmol/L have sufficient predictive ability for AMD.

Conclusion: Significantly reduced capacity of the antioxidant defense system and iron-binding storage proteins (ferritin) found in AMD could have an important role in the development of increase oxidative stress in AMD patients.

KEYWORDS:

• Oxidative stress
• antioxidant defense parameters
• iron
• iron-binding proteins

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Informed consent

Informed consent was obtained from all individual participants included in the study.

Ethical approval

This study was performed according to the Declaration of Helsinki, and the local ethics committee approved this study.

Declaration of interest

The authors report no conflicts of interest.

Additional information

Funding

This study was conducted as a part of the project No. 175036 financially supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia.