title: Metformin restores the correlation between serum-oxidized LDL and leptin levels in type 2 diabetic patients.
abstract: BACKGROUND
  Leptin has lipid peroxidation properties in healthy individuals. Here we aimed to study the correlation between serum-oxidized low-density lipoprotein (ox-LDL) and leptin levels in patients with type 2 diabetes. We also studied the effect of metformin therapy  on the correlation between serum ox-LDL and leptin levels in patients with newly diagnosed diabetes.
  
  
  METHODS
  We performed a cross-sectional study on two groups of patients with type 2 diabetes stratified according to (1) patients with newly diagnosed diabetes and (2) patients  with long-standing diabetes plus healthy controls. Patients with newly diagnosed diabetes were followed for 3 months after the initiation of metformin therapy.
  
  
  RESULTS
  Patients with type 2 diabetes had a higher serum ox-LDL, ox-LDL/LDL ratio, waist circumference, fasting  blood sugars (FBSs), hemoglobin A1C (HbA1C), triglyceride, homeostatic model assessment of insulin resistance (HOMA-IR) and a lower serum leptin levels than controls. Serum ox-LDL, ox-LDL/LDL ratio (0.08 (0.08-0.12) vs. 0.06 (0.05-0.08), P<0.001) and HOMA-IR  (3.26±0.23 vs. 2.93±0.32; P<0.01) were decreased when serum leptin levels (15.9±1.6 vs. 21.4±2.5, P<0.01) were increased after 3 months of metformin therapy. This remained  significant after multiple adjustments for age, body mass index, FBS, HbA1c, and HOMA-IR. Leptin was significantly correlated with ox-LDL/LDL ratio in controls (r=0.78, P<0.01), and in patients with newly diagnosed diabetes (r=0.4,  P<0.05), after metformin therapy. There were not any correlation between leptin and ox-LDL/LDL ratio in patients with long-standing diabetes and patients with newly diagnosed diabetes before treatment.
  
  
  CONCLUSIONS
  Metformin restores the positive correlation  between serum ox-LDL and leptin levels in patients with type 2 diabetes.
authors: Endocrinology and Metabolism Research Center, Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran. nakhjavanim@tums.ac.ir
authors: Manouchehr
authors: M
authors: Nakhjavani
authors: Afsaneh
authors: A
authors: Morteza
authors: Firuzeh
authors: F
authors: Asgarani
authors: Abnoos
authors: A
authors: Mokhtari
authors: Alireza
authors: A
authors: Esteghamati
authors: Omid
authors: O
authors: Khalilzadeh
authors: Ghazaleh
authors: G
authors: Rahbari
mesh_terms: D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy*; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects
chemical_list: D020738:Leptin; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D008687:Metformin