Study I Patients with BMI> 30 and metabolic syndrome. Patient with BMI> 30 without metabolic syndrome. Normal healthy controls. Study II Patients with CKD stage III and uric acid < 7 mg/dl Patients with CKD stage III and uric acid > 7 mg/dl Patient with asymptomatic hiperuricemia and eGFR > 90 ml/min/1.73 m2, , uric acid > 7 mg/dl Hemodialysis patients