Importance of the Use of Oxidative Stress Biomarkers and Inflammatory Profile in Aqueous and Vitreous Humor in Diabetic Retinopathy

Abstract

Diabetic retinopathy is one of the leading causes of visual impairment and morbidity worldwide, being the number one cause of blindness in people between 27 and 75 years old. It is estimated that ~191 million people will be diagnosed with this microvascular complication by 2030. Its pathogenesis is due to alterations in the retinal microvasculature as a result of a high concentration of glucose in the blood for a long time which generates numerous molecular changes like oxidative stress. Therefore, this narrative review aims to approach various biomarkers associated with the development of diabetic retinopathy. Focusing on the molecules showing promise as detection tools, among them we consider markers of oxidative stress (TAC, LPO, MDA, 4-HNE, SOD, GPx, and catalase), inflammation (IL-6, IL-1ß, IL-8, IL-10, IL-17A, TNF-α, and MMPs), apoptosis (NF-kB, cyt-c, and caspases), and recently those that have to do with epigenetic modifications, their measurement in different biological matrices obtained from the eye, including importance, obtaining process, handling, and storage of these matrices in order to have the ability to detect the disease in its early stages.

Evaluation of Redox Profiles of the Serum and Aqueous Humor in Patients with Primary Open-Angle Glaucoma and Exfoliation Glaucoma

“…The activities of superoxide dismutase (SOD) 1 and SOD2 in the AH and serum were measured using the multiplex bead immunoassay system, MILLIPLEX TM MAP Kit (Merck Millipore, Darmstadt, Germany), according to the manufacturer’s instructions, as we previously reported [ 30 ]. SOD1 is a copper- and zinc-dependent form of SOD that is expressed predominantly in the cytosol, and SOD2, a manganese-dependent form of SOD that is expressed predominantly in the mitochondria; SOD1 and SOD2 had been found in serum [ 36 ] and SOD1 in AH [ 37 ]. Based on the information provided by the manufacturer, the multiplex assay kit can quantitatively measure concentrations of analytes as fluorescent reporter signals from as little as 25 µL of bodily fluids.…”

Hub Genes Associated with the Diagnosis of Diabetic Retinopathy

“… 68 In the KEGG pathways of methylation markers enriched, the balance of Notch signaling controls the formation and degeneration of retinal vessels. 9 H 2 O 2 caused a decrease in the concentration of glycine in retina, which is involved in the process of DR. 69 Hyperglycemia induced activation of serine/threonine kinase family proteins is one of the factors involved in microvascular alterations in DM that can lead to DR. 70 …”

Local Inflammatory Biomarkers and Potential Inflammation-Targeting Therapies in Diabetic Retinopathy

“…A positive correlation between IL-6 levels and DR stage was found. IL-6 is involved in synthesis and the release of acute phase reactants and matrix metalloproteinase 9 (MMP-9), decreased tear production, having also a role in the release of IL-1β [26]. TNF-α is a cytokine able to induce the disruption of BRB by loosening the tight junctions between endothelial cells and between RPE cells, with a role in the leukocytes adhesion to the endothelium [13].…”