Plasma YKL-40: a BMI-independent marker of type 2 diabetes.
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.
Nielsen
Anders R
AR
Department of InfectiousDiseases, Facultyof Health Sciences, Centre of Inflammation and Metabolism, Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. rinnov@rh.dk
Erikstrup
Christian
C
Johansen
Julia S
JS
Fischer
Christian P
CP
Plomgaard
Peter
P
Krogh-Madsen
Rikke
R
Taudorf
Sarah
S
Lindegaard
Birgitte
B
Pedersen
Bente K
BK
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
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