title: Association between hyperleptinemia and oxidative stress in obese diabetic subjects.
abstract: BACKGROUND
  Obesity is a worldwide metabolic disorder affecting all types of people. The mechanism by which increased body fat mass that leads to insulin resistance and type 2 diabetes is not yet clearly known. There is a possible crosstalk between leptin, an adipokine and insulin signaling. Leptin mediates insulin sensitivity in hepatocytes; however, its concentration has found to be increased in obese and diabetic subjects. These subjects also have high incidence of oxidative stress status. Therefore, knowing the level of leptin present in obese diabetic subjects will be informative along with its relation to oxidative stress.
  
  
  METHODS
  A small population study was performed to explore the association between leptin concentration and oxidative stress status in control and obese type 2 diabetic subjects. Oxidative stress status parameters like malondialdehyde (MDA), superoxide dismutase activity (SOD), glutathione peroxidase activity (GSH-Px), and protein carbonyl (PCO) groups content was measured spectrophotometrically in serum of 43 subjects. Serum Leptin concentration was measured by quantikine sandwich ELISA assay.
  
  
  RESULTS
  The strong positive correlation between MDA (malondialdehyde) and leptin in obese diabetic patients (ρ = 0.787, P < 0.05) suggests close association between lipid peroxidation and hyperleptinemia. In addition, observed positive correlation between protein carbonyl groups and leptin level in obese diabetic subjects (ρ = 0.599, P = 0.001) suggest that hyperleptinemia might also be associated with increased protein oxidation. In multiple logistic regression analysis, leptin has shown a significant association with obese type 2 diabetes [odds ratio (OR): 1.161, 95% confidence interval (Cl): 1.027-1.312, P < 0.05], but the significance is lost after adjusting for Age, BMI, MDA and anti-oxidant parameters.
  
  
  CONCLUSIONS
  In the subjects with both obesity and diabetes, there is a significant degree of association between hyperleptinemia and oxidative stress. This association reinforces the existing understanding that obese subjects who also have diabetes are vulnerable to cardiovascular complications driven by increased oxidative stress and hyperleptinemia.
authors.affiliation: Centre for Biomedical Research, School of Bio Sciences & Technology, 206, Structural Biology Lab, VIT University, Vellore, India.
authors.forename: Gautam
authors.initials: G
authors.lastname: Pandey
authors.affiliation: Centre for Biomedical Research, School of Bio Sciences & Technology, 206, Structural Biology Lab, VIT University, Vellore, India.
authors.forename: Mohamed Sham
authors.initials: MS
authors.lastname: Shihabudeen
authors.affiliation: Centre for Biomedical Research, School of Bio Sciences & Technology, 206, Structural Biology Lab, VIT University, Vellore, India.
authors.forename: Hansi Priscilla
authors.initials: HP
authors.lastname: David
authors.affiliation: Palar Hospital, Senthil Clinic & Lab, Gudiyattam, India.
authors.forename: Ethirajan
authors.initials: E
authors.lastname: Thirumurugan
authors.affiliation: Centre for Biomedical Research, School of Bio Sciences & Technology, 206, Structural Biology Lab, VIT University, Vellore, India.
authors.forename: Kavitha
authors.initials: K
authors.lastname: Thirumurugan
keywords: Glutathione peroxidase; Leptin; Malondialdehyde; Obesity; Protein carbonyl groups; Superoxide dismutase; Type 2 diabetes