Treatment of Oxidative Stress in Primary Retinal Cells by Heme-Albumin as a Novel Therapeutic Approach for Age-Related Macular Degeneration

Abstract

Purpose : In age-related macular degeneration (AMD) disease progression, oxidative stress from accumulated reactive oxygen species (ROS) and inflammation propagate cellular and tissue damage, leading to retinal pigment epithelium (RPE) dysfunction and vision loss via loss of RPE and/or pathological angiogenesis. In this study, application of a novel heme-human serum albumin (heme-albumin) protein therapeutic is investigated for its potential to reduce oxidative stress in primary retinal cells. In addition, a polydopamine (PDA) nanoparticle (NP) extended-release delivery platform for heme-albumin was also investigated for prolonged therapeutic benefit.

Methods : Heme-albumin PDA NPs were synthesized through self-polymerization in basic conditions before protein loading and exchange into buffer. Primary Müller glial (pMüller) and retinal pigment epithelial (pRPE) cells were isolated from fresh porcine eyes, cultured, and used at passage 1. Cells were plated at 1.5x10⁵/mL for 24 hours before co-treatment of 200 μM hydrogen peroxide and heme-albumin or heme-albumin PDA NPs. Oxidative stress was measured by DCFDA/HDCFDA or Deep Red assay. Unloaded PDA NPs used as control when applicable.

Results : Compared to positive control, considered 100% oxidative stress, heme-albumin dose-dependently reduced oxidative stress with a maximum reduction of 39 ± 21% (p =0.1) in pRPE cells. Further antioxidant benefit against oxidative stress by heme-albumin PDA NPs showed a decrease in oxidative stress of 52 ± 11% (p<0.05) in pRPE cells (Figure 1), elucidating a combined antioxidant effect of heme-albumin and the sustained nanoparticle delivery system, beyond what is accomplished with heme-albumin alone.

Conclusions : Accumulation of reactive species generated within the retina from metabolic function results in cellular and tissue damage, causing the inflammation and vascularization associated with AMD. Heme-albumin has potential as an antioxidant protein therapeutic and its protective benefit against oxidative damage was investigated in primary retinal cells. Reduction in oxidative stress was achieved by heme-albumin and showed further reduction with heme-albumin PDA NPs.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Figure 1. Reduction in oxidative stress by heme-albumin and heme-albumin PDA NPs. Concentrations of heme-albumin PDA NPs above 500 μg/mL were not measured. Results presented as percentage compared to positive control.