title: Changes of dipeptidyl peptidase IV (DPP-IV) in obese children with weight loss: relationships to peptide YY, pancreatic peptide, and insulin sensitivity.
abstract: OBJECTIVE
  Gastrointestinal (GI) hormones are involved in satiety regulation and in glucose metabolism. Most GI hormones are hydrolyzed and inactivated by the same enzyme, dipeptidyl peptidase IV (DPP-IV). We analyzed changes of DPP-IV after weight loss in obese children and its relationships to the GI hormones pancreatic peptide (PP), peptide YY (PYY), and insulin sensitivity.
  
  
  METHODS
  We measured at baseline and one year later anthropometrics, percentage body fat based on skinfold thickness, DPP-IV, PP, PYY, insulin, and glucose concentrations in 18 obese children (mean age 10.9 years, 44% male, mean BMI 28.5 kg/m2) who participated in a one-year lifestyle intervention program based on physical activity, nutrition course, and behavioral therapy. Insulin sensitivity was calculated using QUICKI.
  
  
  RESULTS
  Changes of DPP-IV correlated significantly to the changes of percentage body fat (r = 0.47) and BMI SDS (r = 0.60). In partial regression analysis adjusted for change in weight status, changes of DPP-IV correlated significantly to changes of PYY (r = -0.43), PP (r = -0.49), QUICKI (r = -0.53), and insulin (r = 0.57). The 10 children with substantial weight loss significantly reduced their DPP-IV and insulin concentrations, while QUICKI, PYY, and PP levels significantly increased. In children without substantial weight loss no significant changes were observed.
  
  
  CONCLUSIONS
  These findings suggest that the increase of fasting PP and PYY in weight loss is influenced at least in part by a decrease of their cleavage enzyme DPP-IV. Further research is necessary to evaluate the mechanisms in weight loss leading to a decrease of DPP-IV activity and consequently to an improvement of insulin sensitivity.
authors.affiliation: Department of Pediatric Nutrition Medicine, Vestische Hospital for Children and Adolescents Datteln, University of Witten/Herdecke, Germany. T.Reinehr@kinderklinik-datteln.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinehr
authors.forename: Christian L
authors.initials: CL
authors.lastname: Roth
authors.forename: Pablo J
authors.initials: PJ
authors.lastname: Enriori
authors.forename: Kai
authors.initials: K
authors.lastname: Masur
mesh_terms: D000293:Adolescent; D000553:Ambulatory Care; D001786:Blood Glucose / Q000378:metabolism; D002648:Child; D002662:Child Health Services; D018819:Dipeptidyl Peptidase 4 / Q000097:blood*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008019:Life Style; D008297:Male; D009765:Obesity / Q000097:blood* / Q000628:therapy*; D010191:Pancreatic Polypeptide / Q000097:blood*; D019894:Peptide YY / Q000097:blood*; D016896:Treatment Outcome; D015431:Weight Loss
chemical_list: D001786:Blood Glucose; D007328:Insulin; D019894:Peptide YY; D010191:Pancreatic Polypeptide; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4