Erythropoietin upregulates growth associated protein-43 expression and promotes retinal ganglion cell axonal regeneration in vivo after optic nerve crush

Outbreak of methanol-induced optic neuropathy in early COVID-19 era; effectiveness of erythropoietin and methylprednisolone therapy

BACKGROUND

Methanol is a highly toxic, non-potable alcohol. Outbreaks of methanol toxicity occur due to its fraudulent addition to alcoholic beverages as a cheaper substitute for ethanol. Recently, alongside the coronavirus disease 2019 (COVID-19) pandemic, rumors circulated on social media that consuming alcohol can prevent or cure the virus, leading to a COVID-19 and methanol-induced optic neuropathy (MON) syndemic.

AIM

To investigate the impact of erythropoietin (EPO) on the outcomes of patients diagnosed with MON.

METHODS

In this prospective study, 105 patients presenting with acute bilateral visual loss secondary to methanol intoxication were enrolled from March to May 2020 at Farabi Eye Hospital. A comprehensive ocular examination was conducted for all participants. Recombinant human EPO and methylprednisolone were administered intravenously to all patients for three consecutive days.

RESULTS

The mean age of the participants was 39.9 years (± 12.6). Ninety-four patients were male and eleven were female. The mean pre-treatment best corrected visual acuity (BCVA) improved from 2.0 ± 0.86 to 1.39 ± 0.69 logarithm of the minimum angle of resolution post-treatment (P < 0.001), with significant improvement observed in all age categories and genders (P < 0.001). Visual acuity improvement was also significant regardless of whether the patient presented before or after 72 h (P < 0.001), and the post-treatment BCVA remained significant at all monthly follow-up visits (P < 0.001).

CONCLUSION

EPO and methylprednisolone therapy have been shown to be effective in improving visual outcomes in patients with MON when administrated within the first month of exposure. Public awareness efforts are necessary to prevent further outbreaks of methanol toxicity in the current COVID-19 era.

The Role of Endogenous Neuroprotective Mechanisms in the Prevention of Retinal Ganglion Cells Degeneration

Retinal neurons are not able to undergo spontaneous regeneration in response to damage. A variety of stressors, i.e., UV radiation, high temperature, ischemia, allergens, and others, induce reactive oxygen species production, resulting in consecutive alteration of stress-response gene expression and finally can lead to cell apoptosis. Neurons have developed their own endogenous cellular protective systems. Some of them are preventing cell death and others are allowing functional recovery after injury. The high efficiency of these mechanisms is crucial for cell survival. In this review we focus on the contribution of the most recently studied endogenous neuroprotective factors involved in retinal ganglion cell (RGC) survival, among which, neurotrophic factors and their signaling pathways, processes regulating the redox status, and different pathways regulating cell death are the most important. Additionally, we summarize currently ongoing clinical trials for therapies for RGC degeneration and optic neuropathies, including glaucoma. Knowledge of the endogenous cellular protective mechanisms may help in the development of effective therapies and potential novel therapeutic targets in order to achieve progress in the treatment of retinal and optic nerve diseases.