Calpain and Caspase-12 Expression in Lens Epithelial Cells of Diabetic Cataracts

PURPOSE: To compare the expression of calpain and caspase-12 in human lens epithelial cells (LECs) of cataract patients with or without diabetic retinopathy (DR). DESIGN: Prospective, comparative case series. METHODS: Patients were divided into 4 groups: patients without diabetes mellitus (DM) (Group 1), patients with DM and without diabetic retinopathy (DR) (Group 2), diabetic patients with nonprolifeative DR (NPDR) (Group 3), and diabetic patients with proliferative DR (PDR) (Group 4). Data on DM duration and glycated hemoglobin (HbA1c) level were collected. The LECs were obtained during cataract surgery and immunohistochemical staining was performed for calpain and caspase-12. The reactivity score of each specimen was determined using confocal microscopy. RESULTS: A total of 40 patients (40 eyes) were evaluated, and each group was composed of 10 patients. The expression of calpain and caspase-12 was highest in Group 4, followed by Group 3, Group 2, and Group 1 (P <.001). The expressions were significantly higher with a longer duration of DM, increased HbA1c level, or advanced DR. CONCLUSIONS: Endoplasmic reticulum stress may be associated with apoptosis of LECs, resulting in cataract formation in diabetic patients. (C) 2016 Elsevier Inc. All rights reserved.