In this analysis plasma calprotectin did not show any significant association with autonomic neuropathy (adjusted OR 1.00; 95% CI: 0.958-1.045, p=0.991), PAD (adjusted OR: 1.00; 95% CI: 1.00-1.00, p=0.052), MI (adjusted OR: 1.00; 95% CI: 1.00-1.00, p=0.413) nor CVD (adjusted OR: 1.00; 95% CI: 1.00-1.00, p=0.857). == Discussion == The major findings in our present study were (1) higher levels of plasma calprotectin in T2DM patients compared with a general population, (2) plasma calprotectin levels correlated with BMI, triglyceride, HDL cholesterol (inversely), hs-CRP, insulin and C-peptide levels as well as HOMA-IR in T2DM patients, (3) plasma calprotectin was independently associated with BMI, hs-CRP and HDL cholesterol (inversely), (4) higher levels of plasma calprotectin were found in patients with MetS compared to patients without, and (5) the plasma level of calprotectin was not associated with CVD in T2DM patients but higher levels of plasma calprotectin were found in patients with autonomic neuropathy, PAD and myocardial ischemia compared with patients without. < 0.001, p = 0.021 and p = 0.043, respectively). Plasma calprotectin was by linear regression analysis found independently associated with BMI, C-reactive protein, and HDL cholesterol. However, plasma calprotectin did not predict autonomic neuropathy, PAD, MI or CVD when these variables entered the multivariable regression analysis as separate outcome variables. == Conclusion == T2DM patients had higher concentrations of plasma calprotectin, which were associated with obesity, MetS status, autonomic neuropathy, PAD, and MI. However, plasma calprotectin was not an independent predictor of CVD, MI, autonomic neuropathy or PAD. == Trial registration number == NCT00298844 Keywords:Calprotectin, MRP8/14, Cardiovascular disease, Inflammation, Type 2 diabetes, Obesity, Metabolic syndrome, Automated assay, Reference range == Background == The inflammatory myeloid-related protein complex calprotectin, also known as MRP8/14, is a heterodimer comprised of two intracellular calcium-binding proteins, S100A8 (MRP8) and S100A9 (MRP14), predominantly expressed in activated human neutrophils, monocytes and macrophages. Calprotectin is actively secreted during the stress response of phagocytes [1] and was found to be associated with inflammation more than 20 years ago [2]. Recently, calprotectin was identified as an endogenous activator of Toll-like receptor 4 and as receptor for advanced glycation end products (RAGE) [3] and calprotectin is believed to function both as an intracellular differentiation marker for phagocytes and as an extracellular protein complex (a damage-associated molecular pattern (DAMP) molecule) [4]. Elevated plasma levels of calprotectin have been reported in a variety of chronic inflammatory conditions, including rheumatoid arthritis, allograft rejection, inflammatory bowel disease, cancer and lung diseases [5]. In vivostudies in mice have shown that calprotectin promote atherosclerosis [6]. Furthermore, TSHR elevated calprotectin levels have been reported to predict microvascular alterations in type 2 diabetes (T2DM) patients [7] and was found to be an early and sensitive marker of NSC 185058 acute coronary syndrome [8] and nonfatal myocardial infarction [9]. In a screening approach among healthy individuals, increased plasma concentrations of calprotectin were found to predict the risk of future cardiovascular events [10]. Furthermore, levels of plasma calprotectin appear to increase earlier than other markers of myocardial necrosis (myoglobin, creatine kinaseMB, and troponin), and high levels are associated with an increased risk of recurrent cardiovascular events [9]. T2DM is a disease characterized by increasing insulin resistance over time and is commonly associated with hypertension, hyperlipidemia, and obesity. These patients often has a number of discrete CVD risk factors that together with insulin resistance is known as the metabolic syndrome as defined by the World Health Organization and the NCEP Adult Treatment Panel III [11]. The major death cause in T2DM patients is cardiovascular disease (CVD) [12]. Early identification and characterization of the risk of a cardiovascular event in T2DM patients is therefore important in order to prevent these events. The identification of a biomarker that can predict CVD would therefore be useful in routine clinical use. The aim of the present study was to investigate the association of plasma calprotectin levels with CVD and other complications associated with T2DM in a well-characterized T2DM cohort. == Methods == == Control cohort for establishment of a reference range == Serum samples were obtained from a cohort of 120 adult Danish blood donors in August and September 2011 at Odense University Hospital. All 120 individuals were healthy and fulfilled the general demands for blood donation. Serum samples were obtained from 62 females and 58 males with an age ranging from 19 to 66 years. They were stratified into subgroups by gender and age (<40 years and 40 years). Informed consent was obtained prior to donation of blood and the study was performed according to the Declaration of Helsinki. All samples were aliquoted and stored at 80C until analysis. == Patient cohort == We consecutively evaluated 753 T2DM patients referred to the Diabetes Clinic at Odense University Hospital, Denmark, from January 2006 to December 2007 of which 305 patients met the inclusion criteria as previously reported [13]. Briefly, the inclusion criteria were (1) age >20 years, and (2) fasting C-peptide >250 pmol/L, while the exclusion criteria were (1) any NSC 185058 medical history of CVD (stroke, NSC 185058 myocardial infarction, coronary or peripheral revascularization, or ankle/toe systolic blood pressure <50/30 mmHg), (2) suspected short lifespan due to malignant disease and/or end-stage kidney disease, (3) pregnancy or planned pregnancy during the.