Histopathologic analysis of the internal limiting membrane surgically peeled from eyes with diffuse diabetic macular edema

Abstract

To investigate the pathogenesis of diffuse diabetic maculae edema (DME). Internal limiting membrane (ILM) specimens were surgically peeled from 16 eyes of 15 patients with diffuse DME (diabetic retinopathy (DR) group) and from 12 eyes of 12 patients without diabetes (non-DR group). The specimens were then examined by light microscopy (LM), transmission electron microscopy (TEM), and immunohistochemistry. Examination by LM revealed numerous cells on the inner surface of the ILM specimens in the DR-group, among which five different cell types (glial cell, fibroblast-like cell, macrophages, neutrophils, and lymphocytes) were confirmed. Examination by TEM revealed that the thickness of the peeled ILMs in the DR group was significantly greater, and four types of cellular element (glial, fibroblast-like, macrophages, and lymphocytes) were confirmed on the surface of the vitreous side of the specimens. The existence of glial cells and macrophages was confirmed by immunohistochemistry. In diffuse DME, the ILM is thickened and a variety of cellular elements, especially numerous kinds of inflammatory cell, adhere to the inner surface of the ILM. To attenuate diffuse DME, vitrectomy combined with ILM peeling to remove the inflammatory cells and the physical barrier might be effective.