Serum levels of SOCS6 are decreased in diabetic retinopathy and are related to severity of the disease.

Abstract

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes mellitus (DM). A recent in vitro study found that the suppressor of cytokine signaling 6 (SOCS6) plays a protective role in DR and DM. However, to date, no clinical studies have focused on the role of SOSC6 in DR development. The present study aimed to investigate the expression and clinical significance of serum SOCS6 in DR. A total of 159 DR patients were enrolled in the study. Additionally, 156 type 2 DM (T2DM) patients without DR were recruited as controls. Serum levels of SOCS6, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), vascular endothelial growth factor (VEGF), and angiopoietin-2 (ANG-2) were measured using enzyme-linked immunosorbent assay (ELISA). Demographic and clinical data were collected. Age, the course of DM, systolic blood pressure (SBP), diastolic blood pressure (DBP), and the levels of low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) were significantly higher in proliferative DR (PDR) patients. Serum SOCS6 levels in PDR patients were remarkably lower than in non-PDR patients or non-DR T2DM patients. The Pearson's analysis showed that SOCS6 was negatively correlated with CRP, IL-6, TNF-α, IL-1β, VEGF, and ANG-2. The serum levels of CRP, IL-6, TNF-α, IL-1β, VEGF, and ANG-2 in the SOCS6 low expression group were significantly increased compared to patients with high SOCS6 levels. Receiver operating characteristic (ROC) curves showed that SOCS6 could be a potential diagnostic biomarker for DR. For logistic regression, 3 models were used. It was found that SOCS6, the course of DM, SBP and DBP in model 1, IL-1β and TNF-α in model 2, and VEGF and ANG-2 in model 3 were risk factors for DR. The SOCS6 is decreased in DR patients and is related to severity and clinical outcomes, including inflammatory and angiogenic factors.