Plasma YKL-40

Plasma YKL-40 A BMI-Independent Marker of Type 2 Diabetes Anders R. Nielsen 1 , Christian Erikstrup 1 , Julia S. Johansen 2 , Christian P. Fischer 1 , Peter Plomgaard 1 , Rikke Krogh-Madsen 1 , Sarah Taudorf 1 , Birgitte Lindegaard 1 and Bente K. Pedersen 1 1 Centre of Inflammation and Metabolism, Department of Infectious Diseases and Copenhagen Muscle Research Center, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark 2 Department of Rheumatology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark Corresponding author: Anders Rinnov Nielsen, rinnov{at}rh.dk 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. RESEARCH DESIGN AND 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 (β = 0.5, P = 0.0014) and plasma interleukin (IL)-6 (β = 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. Footnotes Published ahead of print at http://diabetes.diabetesjournals.org on 23 July 2008. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for d