Serum cystatin C and Chemerin levels in diabetic retinopathy

Objective: To investigate the levels of serum cystatin C (CysC) and chemokine (Chemerin) in patients with diabetic retinopathy (DR) and their roles in the onset and progression of DR. Methods: A total of 150 diabetic patients were enrolled as subjects and randomly divided into three groups: the proliferative DR (PDR) group (n=50), the non-proliferative DR (NPDR) group (n=50) and the control group (diabetes mellitus (DM) alone, n=50). In addition, 50 healthy adults were selected as normal controls. The four groups of patients were compared in demographic characteristics and biomarkers including gender, age, body mass index (BMI), glycosylated hemoglobin (HbA1c), homeostasis model assessment of insulin resistance (HOMA-IR), fasting plasma glucose (FPG), triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high sensitive C reactive protein (hsCRP), as well as serum cystatin C and Chemerin levels. Besides, Pearson correlation analysis and Logistics regression analysis were performed. Results: The control group was associated with a significant increase in serum CysC and Chemerin levels as compared with the normal control group; the patients with PDR or NPDR showed significantly higher levels than those with diabetes mellitus (DM) alone; and the ones with PDR had significantly higher levels than those with NPDR. The serum CysC and Chemerin levels were significantly different across groups and increased with the severity of the disease (P<0.05). Pearson correlation analysis showed that the serum CysC levels were positively associated with systolic blood pressure (SBP), HbA1c, HOMA-IR, FPG, TG, TC and LDL-C (P<0.05), and the serum Chemerin levels were positively associated with BMI, HOMA-IR, urinary albumin and hsCRP (P<0.05). What's more, the serum CysC levels were also positively associated with the serum Chemerin levels (P<0.05). Multivariate logistic regression analysis indicated that serums CysC and Chemerin were independent risk factors for DR. Conclusion: Elevated serum CysC and Chemerin levels are risk factors for DR, and they play a role in the pathogenesis of DR. Thus they are likely to become potential markers for assessment of DR.