Autophagy Protects Ocular Cells From Dye Toxicity

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Indocyanine green (ICG) and brilliant blue G (BBG) are 2 vital dyes commonly used to highlight and help remove the internal limiting membrane (ILM) during vitreoretinal surgery. However, researchers have found them toxic to both retinal pigment epithe­lium and photoreceptor cells. Now, researchers in Taiwain have reported that autophagy—a process occurring in cells in response to oxidative stress—may play a role in protecting some types of ocular cells when exposed to these dyes.¹

Autophagy’s role. In the study, genetic and pharmacological ablation of autophagy worsened cytotoxicity of ICG and BBG in mouse ocular cells, indicating that autophagy might act as a survival mechanism in ocular cells exposed to the dyes. Use of dietary sup­plements—such as resveratrol, lutein, and coenzyme Q₁₀ (CoQ₁₀)—induced autophagy, reducing the dyes’ cytotoxic effects.

The results suggest that it is prudent to protect the hole area during stain­ing, said lead researcher Shwu-Jiuan Sheu, MD, at the Kaohsiung Veterans Hospital in Kaohsiung, Taiwan. “This is especially true in macular hole retinal detachment, which allows more direct contact between the dye and photore­ceptors,” she said. “Low doses and short exposure times remain critical during chromovitrectomy.”

Although the researchers found that dietary supplements may play a pro­tective role by boosting autophagy, Dr. Sheu said it was premature to suggest their use for this purpose. “It would be more practical to develop a local agent to help protect against these dyes,” she said. An autophagy inducer might be used in a similar way as rapamycin is used to protect cardiac cells during ischemia/reperfusion injury.

—Annie Stuart

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1 Sheu S-J et al. PLoS ONE. 2017;12(3):e0174736. doi:10.1371/journal.pone.0174736.

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Relevant financial disclosures—Dr. Sheu: This work was supported by Kaohsiung Veterans General Hospital and the Ministry of Science and Technology in Taiwan.

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