ABSTRACT
Purpose: To explore the vitreous humor proteome from type 2 diabetes subjects with proliferative diabetic retinopathy (PDR) in the Indian population. Methods: We performed mass spectrometry?based label?free quantitative analysis of vitreous proteome of PDR (n = 13) and idiopathic macular hole (IMH; control) subjects (n = 14). Nine samples of PDR and 10 samples of IMH were pooled as case and control, respectively, and compared. Four samples each of PDR and IMH were analyzed individually without pooling to validate the results of the pooled analysis. Comparative quantification was performed using Scaffold software which calculated the fold changes of differential expression. Bioinformatics analysis was performed using DAVID and STRING software. Results: We identified 469 proteins in PDR and 517 proteins in IMH vitreous, with an overlap of 172 proteins. Also, 297 unique proteins were identified in PDR and 345 in IMH. In PDR vitreous, 37 proteins were upregulated (P < 0.05) and 19 proteins were downregulated compared to IMH. Protein distribution analysis clearly demonstrated a separation of protein expression in PDR and IMH. Significantly upregulated proteins included fibrinogen gamma chain, fibrinogen beta chain, and carbonic anhydrase 1 and downregulated proteins included alpha?1?antitrypsin, retinol?binding protein 3, neuroserpin, cystatin C, carboxypeptidase E and cathepsin?D. Conclusion: Diabetic retinopathy pathogenesis involves proteins which belong to inflammation, visual transduction, and extracellular matrix pathways. Validation?based experiments using enzyme?linked immunosorbent assay (ELISA) or western blotting are needed to establish cause and effect relationships of these proteins to the disease state, to develop them as biomarkers or drug molecules
ABSTRACT
We aimed to study the histopathological and immunohistochemistry features in clinically diagnosed cases of nanophthalmos using light microscopy. This was an observational comparative study. We enrolled four eyes of four consecutive patients with nanophthalmos and visually significant cataract, who underwent cataract surgery with prophylactic posterior sclerostomy. Histological analysis of the excised scleral tissue was done and compared with age-matched cadaver controls between January 2021 and October 2021. Hematoxylin and Eosin (H&E) stains were used for histological analysis, and was further supplemented with immunohistochemistry (IHC) and immunofluorescence (IF) analyses using a simple light microscope. The immunostained sections were analyzed using confocal microscope for the fibronectin expression level. The main outcome measure was demonstration of histological changes of sclera in nanophthalmic eyes undergoing cataract surgery. Light microscopic features of nanophthalmos revealed thick fibers with fraying and lightly stained cores, irregular serrated edges, and randomly interspersed fibroblasts compared to regular arrangement of collagen fibers seen in cadaver controls. Immunohistochemistry analysis with anti-fibronectin antibody showed strong positivity in clustered fibers in nanophthalmos, and less intense diffuse staining in cadaver tissue. Histoclinical correlation was observed in one nanophthalmic scleral tissue with axial length less than 17 mm showing severe disorganization with diffuse collagenization, loss of fibrillary architecture compared to another specimen with axial length more than 17 mm. Simple, cost-effective light microscopy using basic stains was effective in identifying the characteristic histopathological features in nanophthalmic eyes, and this was further highlighted by immunohistochemistry and immunofluorescence analyses.