Intravitreal erythropoietin injection in late-stage optic neuropathy: a safety study on human

Methanol Induced Optic Neuropathy: Molecular Mysteries, Public Health Perspective, Clinical Insights and Treatment Strategies

Methanol-induced optic neuropathy (MION) represents a critical public health issue, particularly prevalent in lower socioeconomic populations and regions with restricted alcohol access. MION, characterized by irreversible visual impairment, arises from the toxic metabolization of methanol into formaldehyde and formic acid, leading to mitochondrial oxidative phosphorylation inhibition, oxidative stress, and subsequent neurotoxicity. The pathogenesis involves axonal and glial cell degeneration within the optic nerve and potential retinal damage. Despite advancements in therapeutic interventions, a significant proportion of affected individuals endure persistent visual sequelae. The study comprehensively investigates the pathophysiology of MION, encompassing the absorption and metabolism of methanol, subsequent systemic effects, and ocular impacts. Histopathological changes, including alterations in retinal layers and proteins, Müller cell dysfunction, and visual symptoms, are meticulously examined to provide insights into the disease mechanism. Furthermore, preventive measures and public health perspectives are discussed to highlight the importance of awareness and intervention strategies. Therapeutic approaches, such as decontamination procedures, ethanol and fomepizole administration, hemodialysis, intravenous fluids, electrolyte balance management, nutritional therapy, corticosteroid therapy, and erythropoietin (EPO) treatment, are evaluated for their efficacy in managing MION. This comprehensive review underscores the need for increased awareness, improved diagnostic strategies, and more effective treatments to mitigate the impact of MION on global health.

Visual outcome of methanol toxic optic neuropathy after erythropoietin treatment in Riyadh, Saudi Arabia

PURPOSE

The purpose of this study is to evaluate the visual response of methanol-induced optic neuropathy to management with erythropoietin (EPO) along with conventional therapy.

METHODS

This retrospective case series examines the ophthalmological data of patients diagnosed with methanol-induced optic neuropathy between 2020 and 2021 at two centers, Riyadh, Saudi Arabia. Patients' characteristics and the results of initial and final ophthalmological examinations were documented and compared between patients who received EPO in addition to conventional management and those who received only conventional management.

RESULTS

A total of nine cases were reviewed, of which eight (88.9%) were males and one was female (11.1%). The mean age was 37.7 years. At presentation, funduscopic examination revealed optic disc edema in four eyes (two patients), and 14 eyes had normal appearance (seven patients). Among the nine patients who received conventional management, 5 (55.6%) additionally received intravenous EPO during the treatment course. There was no clinically or statistically significant difference in terms of visual outcome between the two groups. The mean visual acuity at the final presentation was 1.32 ± 0.79 logarithm of the minimum angle of resolution (LogMAR) in the EPO group and 1.36 ± 0.85 LogMAR in the non-EPO group. Optical coherence tomography indicated that the EPO group had an average retinal nerve fiber layer thickness of 48.13μm (±6.2), at the final assessment.

CONCLUSION

Managing the visual impairments in individuals with methanol-induced optic neuropathy using intravenous EPO resulted in similar final visual outcomes compared to conventional management.

Toxic and Nutritional Optic Neuropathies—An Updated Mini-Review

Optic neuropathies constitute a group of conditions with various etiologies and might be caused by different factors; we can distinguish the genetic and acquired causes of optic neuropathies. Even though the symptoms are not highly specific, this condition is primarily characterized by unilateral or bilateral vision loss with worsening color detection. The loss may be acute or gradual depending on the causation. In this article, we included a specification of toxic optic neuropathy (TON) mainly triggered by alcohol abuse and also the usage of other substances, including drugs or methanol, as well as intoxication by metals, organic solvents, or carbon dioxide. Nutritional deficiencies, vitamin absorption disorder, and anemia, which usually appear during excessive alcohol intake, and their effect on the etiology of the optic neuropathy have been likewise discussed.

Use of erythropoietin in ophthalmology: a review

Erythropoietin (EPO) is a glycoprotein hormone that regulates hematopoiesis in the human body. The presence of EPO and its receptors in different tissues indicates that this hormone has extramedullary effects in other tissues, including the eye. We focus on the biological roles of this hormone in the development and normal physiologic functions of the eye. Furthermore, we explore the role of EPO in the management of different ocular diseases - including diabetic retinopathy, retinopathy of prematurity, inherited retinal degeneration, branch and central retinal vein occlusion, retinal detachment, traumatic optic neuropathy, optic neuritis, methanol optic neuropathy, nonarteritic anterior ischemic optic neuropathy, glaucoma, and scleral necrosis.

A Promising Strategy for Non-Arteritic Anterior Ischemic Optic Neuropathy: Intravitreal Mesenchymal Stem Cell Exosome

Non-arteritic anterior ischemic optic neuropathy (NAION) is a leading cause of optic nerverelated permanent visual impairment among individuals of over 50 years of age after glaucoma. Due to perplexing disorder regarding its pathogenesis, there is still no widely accepted and established treatment plan. Mesenchymal stem cells (MSCs) are one of the rare stem cell types that therapeutic agents for immunomodulation and ischemic tissue repair in clinical practice. However, there are certain disadvantages in using MSCs, such as potential tumorigenicity, need for autologous collection, and short survival time. Previous evidence suggested that MSC-exosome significantly attenuated post-ischemic neuronal damage and induced long-term neuroprotection associated with enhanced angiogenesis in MSCs. Therefore, we hypothesized that the intravitreal administration of MSC-exosome could be a potentially effective therapeutic approach for NAION by using a similar mechanism via promoting angiogenesis, neuro-regeneration, and neurological recovery, suppressing oxidative stress and reducing apoptosis, and suppressing inflammation and immunity based on its biological structure and function in NAION. Questions that need to be answered before testing clinically include dose regimen, injection frequency, the optimal duration of treatment, and duration of medication.

Illicit drugs: Effects on eye

There is a myriad of changes that can be produced in the eye by toxic drugs ranging from mild/no symptoms to severe loss of vision from endophthalmitis. The routes of administration include oral ingestion, smoking, nasal inhalation, intravenous injection, topical application or application to other mucosal surfaces. It is important to recognize certain clinical signs and symptoms in the eye produced by these toxins. This article describes in brief some of the ocular effects of commonly abused drugs. For identification of a particular poisoning, in addition to the clinical presentation, pulse, blood pressure, respiration and body temperature, pupillary size, pupillary reaction to light, ocular convergence and nystagmus can be useful indicators of the type of drug the patient is exposed to. Unmasking these features help the clinician in an early and accurate diagnosis of the offending drug as well as timely management.

Controversies on neuroprotection therapy in non-arteritic anterior ischaemic optic neuropathy

OBJECTIVE

There has long been a great interest in neuroprotection therapy for ischaemic stroke and various types of optic neuropathies. In view of that, I reviewed the literature on the role of neuroprotection for non-arteritic anterior ischaemic optic neuropathy (NA-AION).

METHODS

The review is based on a PubMed search of literature about the use of neuroprotectors in stroke and optic neuropathies and about current clinical trials of RPh201 and QPI-1007 in NA-AION.

RESULTS

Several neuroprotection agents for ischaemic stroke and various types of optic neuropathies have been evaluated extensively in experimental studies in animals and benefits claimed. However, translation of therapeutic strategies for neuroprotection from experimental research to humans has invariably been fraught with failure. Two currently ongoing studies dealing with neuroprotection by RPh201 and QPI-1007 in NA-AION may have limitations in their rationale and study designs.

CONCLUSIONS

Unfortunately, in spite of all the experimental and clinical research on neuroprotection agents in NA-AION so far, we have no scientifically proven evidence of neuroprotection agents showing any benefit in the human clinical studies so far.

Visual-Evoked-Response-Supported Outcome of Intravitreal Erythropoietin in Management of Indirect Traumatic Optic Neuropathy

PURPOSE

Investigating the efficacy of intravitreal injection of erythropoietin (EPO) in managing indirect traumatic optic neuropathy (ITON) of different durations.

METHODS

A case series that included two groups of ITON patients: recent ITON group (<3 months trauma duration; 7 eyes) and old duration ITON group (3-36 months; 7 eyes). Diagnostic computerized tomography (CT) and baseline flash visual evoked response (VER) were performed at the presentation time. At the initial visit and each follow-up, all patients had undergone assessment of best-corrected visual acuity (BCVA), pupil reaction, and anterior and posterior segments. VER was repeated 1 and 3 months after injection. All patients received an intravitreal injection of 2000 IU EPO in 0.2 ml of commercially available sterile EPREX 4000 solution, Jansen Cilag, Zug, Switzerland. Five patients had received a second injection 3 months later.

RESULTS

Significant improvement was found in BCVA, VER amplitude, and latency (P < 0.0001, 0.0154, and 0.0291, respectively). Initial values of BCVA, VER amplitude, and latency correlated significantly to the final values. Differences between recent and old trauma groups were insignificant in the three parameters. In patients who received second injection, further clinical but statistically insignificant improvement was noted in BCVA in 60% of patients, VER amplitude in 50% of patients, and in VER latency in 100% of patients. No complications were recorded.

CONCLUSION

Intravitreal injection of EPO may be effective and safe in treatment of recent and old indirect traumatic optic neuropathy.