title: Apelin levels are increased in morbidly obese subjects with type 2 diabetes mellitus.
abstract: BACKGROUND
  The physiological role of apelin in obesity and diabetes remains unclear. Although apelin has been studied in persons with different conditions, no studies have yet examined the joint influence of obesity and diabetes on apelin levels. We measured the changes in apelin levels in morbidly obese subjects, with and without diabetes, and in the inverse situation of improvement in carbohydrate metabolism as a result of bariatric surgery.
  
  
  METHODS
  The study was undertaken in 54 morbidly obese persons, 16 of whom had type 2 diabetes mellitus, before and 7 months after undergoing bariatric surgery, and in 12 healthy, nonobese persons. Measurements were made of apelin levels and insulin sensitivity by an intravenous glucose tolerance test.
  
  
  RESULTS
  The apelin levels in the morbidly obese patients prior to surgery were significantly higher than those of the controls only when the morbidly obese subjects were diabetic (P < 0.005). Apelin levels correlated significantly in the morbidly obese patients with serum triglycerides (r = 0.292, P = 0.032) and glucose (r = 0.337, P = 0.039). Bariatric surgery resulted in a significant decrease in apelin levels only in the morbidly obese subjects with impaired fasting glucose or diabetes. The change in apelin levels correlated significantly in the morbidly obese patients with the changes in serum glucose (r = 0.338, P = 0.038) and insulin sensitivity (r = -0.417, P = 0.043).
  
  
  CONCLUSIONS
  This study demonstrates that obesity is not the main determinant of the rise in apelin levels. The association between apelin levels and glucose concentrations and insulin sensitivity provides evidence that apelin may play a role in the pathogenesis of diabetes.
authors.affiliation: Servicio de Endocrinología y Nutrición, Hospital Regional Universitario Carlos Haya, Málaga, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Soriguer
authors.forename: Lourdes
authors.initials: L
authors.lastname: Garrido-Sanchez
authors.forename: Sara
authors.initials: S
authors.lastname: Garcia-Serrano
authors.forename: Jose M
authors.initials: JM
authors.lastname: Garcia-Almeida
authors.forename: Juan
authors.initials: J
authors.lastname: Garcia-Arnes
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Tinahones
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia-Fuentes
mesh_terms: D000328:Adult; D000073861:Apelin; D050110:Bariatric Surgery; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood*; D008297:Male; D009767:Obesity, Morbid / Q000097:blood* / Q000150:complications / Q000601:surgery; D014280:Triglycerides / Q000097:blood; D015431:Weight Loss / Q000502:physiology*
chemical_list: C115436:APLN protein, human; D000073861:Apelin; D001786:Blood Glucose; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D014280:Triglycerides