Glutathione Peroxidase as an Oxidative Stress and Insulin Resistance Marker in a group of Egyptian Patients with Normoglycemic Sickle Cell Disease

Abstract

Background: Sickle cell disease (SCD) which is characterized by abnormal hemoglobin structure has a carrier rate of 9-20% in Egypt. Reactive oxygen species (ROC) in SCD cause multiple organ injuries, endocrine complications and metabolic alteration such as insulin resistance (IR) in children and young adults. We aimed to determine the presence of IR in normoglycemic SCD patients and also assessing the concentration of glutathione peroxidase (GPX) and its correlation with insulin resistance in patients with SCD. Methods: Sixty patients were enlisted from pediatric hematology outpatient clinic, Cairo university hospital together with 31 age and sex-matched healthy children not suffering SCD or other hematological disorders. Oral glucose tolerance test (OGTT) was checked at the beginning. Serum fasting insulin levels and glutathione peroxidase measurement was done using enzyme-linked immunosorbent assay (ELISA). Beta cell function and insulin resistance was calculated using the “Homeostasis Model of Assessment” according to the following equation (fasting insulin x fasting glucose)/22.5. Calculations are based on mmol/l for glucose and mU/ml for insulin considering values more than 1.4 as insulin resistance (IR) Results: There were no impaired glucose tolerance in both patients and control group. On calculating HOMA-IR, 34 (56.7%) had IR compared to the absence of IR in 26 (43.3%) and all the subjects in the control group (P<0.001). Patients with SCD had lower GPX concentration than the control group with negative correlation with serum insulin and insulin resistance. Conclusion: The correlation between oxidative stress markers represented by GPX and the development of insulin resistance despite normal serum glucose levels.