title: Plasma YKL-40: a BMI-independent marker of type 2 diabetes.
abstract: OBJECTIVE
  YKL-40 is produced by macrophages, and plasma YKL-40 is elevated in patients with diseases characterized by inflammation. In the present study, YKL-40 was examined in relation to obesity, inflammation, and type 2 diabetes.
  
  
  METHODS
  Plasma YKL-40 and adipose tissue YKL-40 mRNA levels were investigated in 199 subjects who were divided into four groups depending on the presence or absence of type 2 diabetes and obesity. In addition, plasma YKL-40 was examined in healthy subjects during a hyperglycemic clamp, in which the plasma glucose level was kept at 15 mmol/l for 3 h, and during a hyperinsulinemic-euglycemic clamp.
  
  
  RESULTS
  Patients with type 2 diabetes had higher plasma YKL-40 (76.7 vs. 45.1 ng/ml, P = 0.0001) but not higher expression in adipose tissue YKL-40 mRNA (1.20 vs. 0.98, P = 0.2) compared with subjects with a normal glucose tolerance. Within the groups with normal glucose tolerance and type 2 diabetes, obesity subgroups showed no difference with respect to either plasma YKL-40 or adipose tissue YKL-40 mRNA levels. Multivariate regression analysis showed that plasma YKL-40 was associated with fasting plasma glucose (beta = 0.5, P = 0.0014) and plasma interleukin (IL)-6 (beta = 0.2, P = 0.0303). Plasma YKL-40 was not related to parameters of obesity. There were no changes in plasma YKL-40 in healthy subjects during either hyperglycemic or hyperinsulinemic-euglycemic clamps.
  
  
  CONCLUSIONS
  Plasma YKL-40 was identified as an obesity-independent marker of type 2 diabetes related to fasting plasma glucose and plasma IL-6 levels.
authors.affiliation: Department of InfectiousDiseases, Facultyof Health Sciences, Centre of Inflammation and Metabolism, Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. rinnov@rh.dk
authors.forename: Anders R
authors.initials: AR
authors.lastname: Nielsen
authors.forename: Christian
authors.initials: C
authors.lastname: Erikstrup
authors.forename: Julia S
authors.initials: JS
authors.lastname: Johansen
authors.forename: Christian P
authors.initials: CP
authors.lastname: Fischer
authors.forename: Peter
authors.initials: P
authors.lastname: Plomgaard
authors.forename: Rikke
authors.initials: R
authors.lastname: Krogh-Madsen
authors.forename: Sarah
authors.initials: S
authors.lastname: Taudorf
authors.forename: Birgitte
authors.initials: B
authors.lastname: Lindegaard
authors.forename: Bente K
authors.initials: BK
authors.lastname: Pedersen
mesh_terms: D054392:Adipokines; D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D015703:Antigens, CD / Q000235:genetics; D015214:Antigens, Differentiation, Myelomonocytic / Q000235:genetics; D015415:Biomarkers / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D016022:Case-Control Studies; D000071451:Chitinase-3-Like Protein 1; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000175:diagnosis / Q000235:genetics; D005260:Female; D015309:Glucose Clamp Technique; D006023:Glycoproteins / Q000097:blood* / Q000235:genetics; D006801:Humans; D037102:Lectins; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012044:Regression Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000097382:CD68 Molecule
chemical_list: D054392:Adipokines; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D001786:Blood Glucose; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins; D012333:RNA, Messenger; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C084533:CHI3L1 protein, human