Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium.

Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.

Therapeutic Penetrating Keratoplasty Button Cultures in The Mycotic Ulcer Treatment Trial II: A Randomized Trial Comparing Oral Voriconazole Versus Placebo.

OBJECTIVE: To compare oral voriconazole vs placebo in addition to topical antifungals in the treatment of filamentous fungal keratitis. DESIGN: Non-prespecified, secondary case-control analysis from a multicenter, double-masked, randomized placebo-controlled clinical trial. METHODS: Study Participants: Patients with smear-positive filamentous fungal ulcers and visual acuity of 20/400 or worse who eventuated to therapeutic penetrating keratoplasty (TPK). INTERVENTION: Study participants were randomized to oral voriconazole vs oral placebo; all received topical antifungal drops. MAIN OUTCOME MEASURES: TPK button culture positivity. RESULTS: A total of 95 of 194 (49.5%) study participants enrolled at Madurai, Coimbatore, or Pondicherry, India eventuated to TPK in an average of 20.9 days (standard deviation 15.2 days, range 2-71 days). TPK button cultures were available for 67 of 95 (71%) of the TPKs performed and were positive for filamentous fungus in 45 of 67 (67%) cases. For each 1-day increase in the time to TPK there was 0.94-fold decreased odds of fungal culture positivity (95% confidence interval [CI] 0.90-0.98, P = .005). Those randomized to oral voriconazole had 1.26-fold increased odds of TPK button culture positivity after controlling for time to TPK and baseline organism, but this was not statistically significant (95% CI 0.32-4.87; P = .74). Those who underwent TPK for lack of response to medical therapy were 10.64-fold more likely to be culture positive than if the indication for surgery was perforation and this was statistically significant (95% CI 2.16-51.70; P = .003). CONCLUSIONS: There appears to be no benefit to adding oral voriconazole to topical antifungal agents in the treatment of severe filamentous fungal ulcers. Infection rather than inflammation appears to be the reason for the worsening clinical picture in many of these patients.