The potential neuroprotective effects of weekly treatment with glatiramer acetate in diabetic patients after panretinal photocoagulation

Abstract

Somaia Mitne1,2, Sergio Henrique Teixeira1, Michal Schwartz3, Michael Belkin4, Michel Eid Farah1, Nilva S Bueno de Moraes1, Luciana da Cruz Nóia1, Ângela Tavares Paes2, Cláudio Luiz Lottenberg2, Augusto Paranhos Júnior1,21Department of Ophthalmology, Federal University of São Paulo, 2Instituto Israelita de Ensino e Pesquisa Albert Einstein, HIAE, São Paulo, Brazil; 3Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 4Goldschleger Eye Research Institute, Tel-Aviv University, Sheba Medical Center, Tel HaShomer, IsraelPurpose: Evaluation of the neuroprotective effect of weekly glatiramer acetate (GA) on retinal structure and function in diabetic patients who underwent panretinal photocoagulation (PRP).Patients and methods: Patients with severe nonproliferative or early proliferative diabetic retinopathy and no previous laser treatment were randomly divided into two groups: (1) those who received four GA treatments and (2) those who received placebo treatment. The subcutaneous injections were administered 1 week prior to laser and weekly in the subsequent three sessions of PRP in both groups. All patients underwent a full ophthalmic examination (best-corrected logMAR visual acuity, slit lamp examination, applanation tonometry, fundus biomicroscopy and indirect fundus examination); functional examination (standard automated perimetry, electroretinography and frequency-doubling technology C-20 visual field) and anatomic examination (color photography, optical coherence tomography (OCT) and Heidelberg retinal tomography). The examinations were performed before the photocoagulation and repeated 1,3,6, and 12 months after treatment (in a double-masked manner). To compare the two groups, generalized estimating equation models were performed to account for the dependence between eyes of the same patient.Results: Thirteen patients (23 eyes) were included in the study group and 13 patients (24 eyes) were included in the control group. OCT showed a statistically significant difference in retinal nerve fiber layer (RNFL) thickness in the inferior peripapillary region and average thickness with thinner measurements in the control group at 1-year post-PRP. Functional analysis demonstrated a difference between groups, but it did not reach statistical significance.Conclusion: The results of this study suggest that weekly GA treatment has a potential neuroprotective effect on the RNFL following photocoagulation for diabetic retinopathy.Keywords: diabetic retinopathy, panretinal photocoagulation, glatiramer acetate, neuroprotection