PEG-Arginase 1: A Novel Therapy for Optic Nerve Injury

Traumatic optic neuropathy (TON) is a major cause of visual impairment, resulting from direct or indirect damage to the optic nerve. Researchers have investigated the role of the arginase 1 (A1) enzyme in this condition, finding that treatment with a long-acting form, PEG-A1, can reduce inflammation and protect visual function. To confirm these findings, they conducted studies on mouse models of direct and indirect TON, administering PEG-A1 systemically or intravitreally at various intervals post-injury.

By analyzing cellular mechanisms, they discovered that PEG-A1 limits retinal inflammation and injury, promoting visual recovery and neuronal survival. This protective effect is attributed to the activation of the ornithine/polyamine pathway, where PEG-A1 facilitates the conversion of L-ornithine to polyamines, which promote reparative functions.

Importantly, inhibiting the ornithine decarboxylase (ODC) enzyme with difluoromethylornithine (DFMO) negated these protective effects, confirming the critical role of the A1-induced ornithine/polyamine pathway in PEG-A1's therapeutic efficacy. The study reveals PEG-A1 as a novel approach to mitigate trauma-induced vision loss and support retinal repair after optic nerve injury.