Research Article: Correlation between various trace elements and ultramicroscopic structure of epiretinal macular membranes and glial cells

Date Published: September 28, 2018

Publisher: Public Library of Science

Author(s): Mario R. Romano, Gilda Cennamo, Daniela Montorio, Salvatore Del Prete, Mariantonia Ferrara, Giovanni Cennamo, Demetrios G. Vavvas.


Elements such as zinc, iron, copper, sulphur and phosphorus have been identified in retinal layers and implicated in vital retinal functions. Regarding mineral composition of epiretinal membranes (ERMs), literature is lacking. This study aimed to analyze both mineral composition and anatomical ultrastructure of ERMs to clarify the pathophysiology of this disease.

Twenty ERMs (10 diabetic ERMs and 10 idiopathic ERMs) from 20 patients were harvested during pars plana vitrectomy. Scanning Electron Microscopy (SEM) was used to investigate the anatomical ultrastructure of the peeled ERMs. Mineral composition was analyzed using energy-dispersive spectrometry (EDS). The most frequent elements were evaluated in relation to appearance of ERMs analyzed at SEM and at OCT images.

Sulphur was the most frequent element found (in 80% of the samples), followed by sodium (50%) and phosphorus (45%). The presence of these elements was not significantly different between diabetic and idiopathic ERMs (P >0.05). Using SEM we found a folded tissue in all ERMs, except in 4 ERMs, where we observed only a smooth tissue. There was a trend of sodium to be more frequent in ERMs with folded layers at SEM examination.

Several elements were identified in ERMs, and sulphur, sodium and phosphorus were the most frequent ones. This finding may help to understand their role in the physiopatology of epiretinal proliferation and in glial activation.

Partial Text

Epiretinal membrane (ERM) is the most common type of fibrocellular proliferation at the vitreoretinal interface and is significantly associated with aging [1–3].

In this prospective study we evaluated 20 ERMs of 20 consecutive patients enrolled in the Eye Clinic of the University of Naples “Federico II” from July to October 2016. Before undergoing surgery, all patients signed a written informed consent. The study was approved by the Institutional Review Board of the University of Naples “Federico II” and all investigations adhered to the tenets of the Declaration of Helsinki. We included 10 idiopathic ERMs (iERMs) and 10 ERMs secondary to diabetic retinopathy (dERMs). Exclusion criteria were previous ophthalmic laser and surgical treatment, intravitreal injection, vascular occlusions, inflammatory eye diseases, history of ocular trauma and significant ocular media opacities precluding an adequate fundus and optical coherence tomography (OCT) examination.

Twenty ERMs surgically removed from 20 eyes of 20 patients (10 females and 10 males) were examined. The mean age was 65.5 ± 9.77 years and the mean preoperative BCVA was 0.66 ±0.18 logMAR. Ten of 20 patients were affected by dERM and 10 by iERM.

To our knowledge, this is the first study analyzing both the mineral composition and anatomical ultrastructure in ERMs using SEM/EDS.




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