Soluble urokinase plasminogen activator receptor levels are elevated and associated with complications in patients with type 1 diabetes.

OBJECTIVES: Soluble urokinase plasminogen activator receptor (suPAR) is a marker of inflammation and endothelial dysfunction. We investigated the associations between suPAR and diabetes, including diabetes duration and complications, in patients with type 1 diabetes. DESIGN, SETTING AND SUBJECTS: From 2009 to 2011, 667 patients with type 1 diabetes and 51 nondiabetic control subjects were included in a cross-sectional study at Steno Diabetes Center, Gentofte, Denmark. suPAR levels were measured with an enzyme-linked immunosorbent assay. MAIN OUTCOME MEASURES: The investigated diabetic complications were cardiovascular disease (CVD: previous myocardial infarction, revascularisation, peripheral arterial disease and stroke), autonomic dysfunction (heart rate variability during deep breathing <11 beats min(-1) ), albuminuria [urinary albumin excretion rate (UAER) ≥30 mg/24 h] or a high degree of arterial stiffness (pulse wave velocity ≥10 m s(-1) ). Analyses were adjusted for gender, age, systolic blood pressure, estimated glomerular filtration rate, UAER, glycated haemoglobin (HbA1c ), total cholesterol, body mass index, C-reactive protein, antihypertensive treatment and smoking. RESULTS: Soluble urokinase plasminogen activator receptor levels were lower in control subjects versus all patients, in control subjects versus normoalbuminuric patients (UAER <30 mg/24 h), in normoalbuminuric patients with short (<10 years) versus long diabetes duration and were increased with degree of albuminuria (adjusted P < 0.001 for all). Furthermore, suPAR levels were higher in patients with versus without CVD (n = 144; 21.3%), autonomic dysfunction (n = 369; 59.2%), albuminuria (n = 357; 53.1%) and a high degree of arterial stiffness (n = 298; 47.2%) (adjusted P ≤ 0.024). The adjusted odds ratio (95% confidence interval) values per 1 ln unit increase in suPAR were as follows: 2.5 (1.1-5.7) for CVD: 2.7 (1.2-6.2) for autonomic dysfunction; 3.8 (1.3-10.9) for albuminuria and 2.5 (1.1-6.1) for a high degree of arterial stiffness (P ≤ 0.039). CONCLUSION: The suPAR level is higher in patients with type 1 diabetes and is associated with diabetes duration and complications independent of other risk factors. suPAR is a potential novel risk marker for the management of diabetes.

Soluble urokinase plasminogen activator receptor is associated with subclinical organ damage and cardiovascular events.

OBJECTIVE: The soluble urokinase plasminogen activator receptor (suPAR) is a plasma marker of low grade inflammation and has been associated with cardiovascular risk. We wanted to investigate whether suPAR was associated with markers of subclinical organ damage. METHODS: In a population sample of 2038 individuals, aged 41, 51, 61 and 71 years, without diabetes, prior stroke or myocardial infarction, not receiving any cardiovascular, anti-diabetic or lipid-lowering medications, we measured urine albumin/creatinine ratio (UACR), carotid atherosclerotic plaques and carotid/femoral pulse wave-velocity (PWV) together with traditional cardiovascular risk factors and high sensitivity C-reactive protein (hsCRP). RESULTS: suPAR was significantly associated with the presence of plaques (P = 0.003) and UACR (P < 0.001), but not PWV (P = 0.17) when adjusting for age, gender, systolic blood pressure, cholesterol, plasma glucose, waist/hip ratio, smoking and hsCRP. However, suPAR explained only a small part of the variation in the markers of subclinical organ damage (R(2) 0.02-0.04). During a median follow-up of 12.7 years (5th-95th percentile 5.1-13.4 years) a total of 174 composite endpoints (CEP) of cardiovascular death, non-fatal myocardial infarction and stroke occurred. suPAR was associated with CEP independent of plaques, PWV, UACR, and hsCRP as well as age, gender, systolic blood pressure, cholesterol, plasma glucose, waist/hip ratio and smoking with a standardized hazard ratio of 1.16 (95% confidence interval 1.04-1.28, P = 0.006). CONCLUSION: suPAR was associated with subclinical organ damage, but predicted cardiovascular events independent of subclinical organ damage, traditional risk factors and hsCRP. Further studies must investigate whether suPAR plays an independent role in the pathogenesis of cardiovascular disease.

Circulating soluble urokinase plasminogen activator receptor predicts cancer, cardiovascular disease, diabetes and mortality in the general population.

BACKGROUND: Low-grade inflammation is thought to contribute to the development of cardiovascular disease (CVD), type-2 diabetes mellitus (T2D), cancer and mortality. Biomarkers of inflammation may aid in risk prediction and enable early intervention and prevention of disease. OBJECTIVE: The aim of this study was to investigate whether plasma levels of the inflammatory biomarker soluble urokinase plasminogen activator receptor (suPAR) are predictive of disease and mortality in the general population. DESIGN: This was an observational prospective cohort study. Cohort participants were included from June 1993 to December 1994 and followed until the end of 2006. SETTING: General adult Caucasian population. PARTICIPANTS: The MONICA10 study, a population-based cohort recruited from Copenhagen, Denmark, included 2602 individuals aged 41, 51, 61 or 71 years. MEASUREMENTS: Blood samples were analysed for suPAR levels using a commercially available enzyme-linked immunosorbent assay. Risk of cancer (n = 308), CVD (n = 301), T2D (n = 59) and mortality (n = 411) was assessed with a multivariate proportional hazards model using Cox regression. RESULTS: Elevated baseline suPAR level was associated with an increased risk of cancer, CVD, T2D and mortality during follow-up. suPAR was more strongly associated with cancer, CVD and mortality in men than in women, and in younger compared with older individuals. suPAR remained significantly associated with the risk of negative outcome after adjustment for a number of relevant risk factors including C-reactive protein levels. LIMITATION: Further validation in ethnic populations other than Caucasians is needed. CONCLUSION: The stable plasma protein suPAR may be a promising biomarker because of its independent association with incident cancer, CVD, T2D and mortality in the general population.

Modeling the interactions of a peptide-major histocompatibility class I ligand with its receptors. I. Recognition by two alpha beta T cell receptors.

A three-dimensional model of the complex between an Influenza Hemagglutinin peptide, Ha255-262, and its restricting element, the mouse major histocompatibility complex (MHC) class I molecule, Kk, was built by homology modeling and subsequently refined by simulated annealing and restrained molecular dynamics. Next, three-dimensional models of two different T cell receptors (TCRs) both specific for the Ha255-262/Kk complex were generated based on previously published TCR X-ray structures. Finally, guided by the recently published X-ray structures of ternary TCR/peptide/MHC-I complexes, the TCR models were successfully docked into the Ha255-262/Kk model. We have previously used a systematic and exhaustive panel of 144 single amino acid substituted analogs to analyze both MHC binding and T cell recognition of the parental viral peptide. This large body of experimental data was used to evaluate the models. They were found to account well for the experimentally obtained data, lending considerable support to the proposed models and suggesting a universal docking mode for alpha beta TCRs to MHC-peptide complexes. Such models may also be useful in guiding future rational experimentation.