Cardiovascular risk prediction in the general population with use of suPAR, CRP, and Framingham Risk Score

New Cardiovascular Biomarkers in Ischemic Heart Disease-GDF-15, A Probable Predictor for Ejection Fraction

BACKGROUND

Various biomarkers have been associated with coronary artery disease (CAD) and ischemic heart failure. The aim of this study was to investigate the correlation of serum levels of soluble urokinase-type plasminogen activator receptor (suPAR), growth differentiation factor 15 (GDF-15), heart-type fatty acid-binding protein (H-FABP), and soluble suppression of tumorigenicity 2 (sST2) with left ventricular ejection fraction (EF) in CAD patients and controls.

METHODS AND RESULTS

CAD patients were divided into three groups according to their EF as measured by the biplane Simpson method (53-84%, 31-52%, ≤30%). Overall, 361 subjects were analyzed. In total, 155 CAD patients had an EF of 53-84%, 71 patients had an EF of 31-52%, and 23 patients had an EF of ≤30% as compared to 112 healthy controls (age 51.3 ± 9.0 years, 44.6% female). Mean ages according to EF were 62.1 ± 10.9, 65.2 ± 10.1, and 66.6 ± 8.2 years, respectively, with females representing 29.0, 29.6, and 13.0%. suPAR, GDF-15, H-FABP, and sST2 values were significantly higher in CAD patients and showed an exponential increase with decreasing EF. In a multiple logistic regression model, GDF-15 (p = 0.009), and NT-brain natriuretic peptide (p = 0.003) were independently associated with EF.

CONCLUSION

Biomarkers such as suPAR, GDF-15, H-FABP, and sST2 are increased in CAD patients, especially in highly impaired EF. Besides NT-proBNP as a well-known marker for risk prediction, GDF-15 may be an additional tool for diagnosis and clinical follow-up.

Soluble Urokinase Plasminogen Activator Receptor and Decline in Kidney Function in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Levels of soluble urokinase plasminogen activator receptor (suPAR), an inflammation marker, are strongly predictive of incident kidney disease. Patients with autosomal dominant polycystic kidney disease (ADPKD) experience progressive decline in renal function, but rates of decline and outcomes vary greatly. Whether suPAR levels are predictive of declining kidney function in patients with ADPKD is unknown.

METHODS

We assessed suPAR levels in 649 patients with ADPKD who underwent scheduled follow-up for at least 3 years, with repeated measurements of height-adjusted total kidney volume and creatinine-derived eGFR. We used linear mixed models for repeated measures and Cox proportional hazards to characterize associations between baseline suPAR levels and follow-up eGFR or incident ESRD.

RESULTS

The median suPAR level was 2.47 ng/ml and median height-adjusted total kidney volume was 778, whereas mean eGFR was 84 ml/min per 1.73 m². suPAR levels were associated with height-adjusted total kidney volume (β=0.02; 95% confidence interval, 0.01 to 0.03), independent of age, sex, race, hypertension, and eGFR. Patients in the lowest suPAR tertile (<2.18 ng/ml) had a 6.8% decline in eGFR at 3 years and 22% developed CKD stage 3, whereas those in the highest tertile (suPAR>2.83 ng/ml) had a 19.4% decline in eGFR at 3 years and 68% developed CKD stage 3. suPAR levels >2.82 ng/ml had a 3.38-fold increase in the risk of incident ESRD.

CONCLUSIONS

suPAR levels were associated with progressive decline in renal function and incident ESRD in patients with ADPKD, and may aid early identification of patients at high risk of disease progression.

Analytical, biochemical and clearance considerations of soluble urokinase plasminogen activator receptor (suPAR) in healthy individuals

BACKGROUND

Soluble urokinase plasminogen activator receptor (suPAR) is an emerging marker of cardiovascular disease burden. Appropriate assessment of assay performance and reference interval are required to enable interpretation of results to facilitate its clinical application.

METHODS

suPAR was measured using the suPARnostic® ELISA in 155 healthy volunteers. Assay performance was assessed for anticoagulant effect, recovery, interference, linearity and cross-reactivity. The identity of immunoreactive suPAR was confirmed by size-exclusion HPLC. To establish anatomical sites of release and uptake, we measured suPAR in regional samples from subjects undergoing cardiac catheterization.

RESULTS

The median concentration of suPAR was 2.1 ng/mL (IQR:1.7-2.3) in health. In comparison with EDTA, suPAR measurements were affected by lithium heparin (>10% change) and increased with serum usage. suPAR reactivity also increased in the presence of haemolysis (10 g/L), but was suppressed with urokinase and lipids (4 g/L). In multiple regression analyses, suPAR associated independently with body weight, NT-proBNP and MR-proADM (P = .03) for healthy individuals. Regional plasma sampling showed lower suPAR concentrations in the coronary sinus and renal vein compared with concentrations in femoral arterial samples. Immunoreactive circulating suPAR species had M_r of 10-39 kDa.

CONCLUSION

The suPARnostic® assay performs acceptably for a clinical assay but is limited in the presence of high levels of hemolysis, lipids and urokinase. We provide the first evidence for the heart and kidneys as organs of suPAR clearance in humans. Additional investigations are warranted to determine whether there is a need to compare the marker performance of differing circulating forms of suPAR.

Sudden Cardiac Death (SCD) - risk stratification and prediction with molecular biomarkers

Sudden cardiac death (SCD) is a sudden, unexpected death that is caused by the loss of heart function. While SCD affects many patients suffering from coronary artery diseases (CAD) and heart failure (HF), a considerable number of SCD events occur in asymptomatic individuals. Certain risk factors for SCD have been identified and incorporated in different clinical scores, however, risk stratification using such algorithms is only useful for health management rather than for early detection and prediction of future SCD events in high-risk individuals. In this review, we discuss different molecular biomarkers that are used for early detection of SCD. This includes genetic biomarkers, where the majority of them are genomic variants for genes that encode for ion channels. Meanwhile, protein biomarkers often denote proteins that play roles in pathophysiological processes that lead to CAD and HF, notably (i) atherosclerosis that involves oxidative stress and inflammation, as well as (ii) cardiac tissue damage that involves neurohormonal and hemodynamic regulation and myocardial stress. Finally, we outline existing challenges and future directions including the use of OMICS strategy for biomarker discovery and the multimarker panels.

Predictive value of soluble urokinase-type plasminogen activator receptor for mortality in patients with suspected myocardial infarction

BACKGROUND

Early risk stratification of patients with suspected acute myocardial infarction (AMI) constitutes an unmet need in current daily clinical practice. We aimed to evaluate the predictive value of soluble urokinase-type plasminogen activator receptor (suPAR) levels for 1-year mortality in patients with suspected AMI.

METHODS AND RESULTS

suPAR levels were determined in 1314 patients presenting to the emergency department with suspected AMI. Patients were followed up for 12 months to assess all-cause mortality. Of 1314 patients included, 308 were diagnosed with AMI. Median suPAR levels did not differ between subjects with AMI compared to non-AMI (3.5 ng/ml vs. 3.2 ng/ml, p = 0.066). suPAR levels reliably predicted all-cause mortality after 1 year. Hazard ratio for 1-year mortality was 12.6 (p < 0.001) in the quartile with the highest suPAR levels compared to the first quartile. The prognostic value for 6-month mortality was comparable to an established risk prediction model, the Global Registry of Acute Coronary Events (GRACE) score, with an AUC of 0.79 (95% CI 0.72-0.86) for the GRACE score and 0.77 (95% CI 0.69-0.84) for suPAR. Addition of suPAR improved the GRACE score, as shown by integrated discrimination improvement statistics of 0.036 (p = 0.03) suggesting a further discrimination of events from non-events by the addition of suPAR.

CONCLUSIONS

suPAR levels reliably predicted mortality in patients with suspected AMI.

STUDY REGISTRATION

http://www.clinicaltrials.gov (NCT02355457).

SuPAR correlates with mortality and clinical severity in patients with necrotizing soft-tissue infections: results from a prospective, observational cohort study

Necrotizing soft tissue infections (NSTI) have a 90-day mortality rate of 18–22%. Tools are needed for estimating the prognosis and severity of NSTI upon admission. We evaluated soluble urokinase-type plasminogen activator receptor (suPAR) levels at admission as a prognostic marker of NSTI severity and mortality. In a prospective, observational cohort study, suPAR was measured in 200 NSTI patients. We compared admission suPAR levels in survivors and non-survivors, patients with septic shock and non-shock, amputation and non-amputation, correlations with Simplified Acute Physiology Score II (SAPS II) and the Sequential Organ Failure Assessment (SOFA) score. Admission suPAR levels were higher in septic shock vs. non-septic shock patients (9.2 vs. 5.8 ng/mL, p-value < 0.001) and non-survivors vs. survivors (11 vs. 6.1 ng/mL, p-value < 0.001) and correlated with SAPS II (r = 0.52, p < 0.001) and SOFA score (r = 0.64, p < 0.001). Elevated suPAR upon admission was associated with 90-day mortality (log-rank test p < 0.001), however not after adjustment for age, sex, and SOFA score. The AUC for suPAR and 90-day mortality was 0.77. We found that suPAR is a promising candidate for prognosis and severity in patients with NSTI.

Soluble urokinase plasminogen activation receptor and long-term outcomes in persons undergoing coronary angiography

Soluble urokinase plasminogen activation receptor (suPAR) is risk factor for kidney disease and biomarker for cardiovascular outcomes but long term longitudinal analyses in a large European cohort have not been perfomed. To hus, we studied suPAR in participants of the Ludwigshafen Risk and Cardiovascular Health study over a very long follow-up time of nearly 10 years. We estimated overall risk of all-cause and cardiovascular death by Cox proportional hazards regression according to quartiles of suPAR, including age, sex, use of lipid-lowering drugs, body mass index, diabetes mellitus, hypertension, smoking, lipids, as well as glomerular filtration rate (eGFR), NT-proBNP, interleukin-6 and high-sensitive CRP as covariates. A total of 2940 participants (age 62.7 ± 10.5years) having a median eGFR of 83.8 mL/min/1.73 m² were included. The median suPAR concentration was 3010 pg/mL (interquartile range, 2250–3988 pg/mL). Using the lowest quartile of suPAR as the reference, crude hazard ratio for cardiovascular mortality were 1.58 (95% CI 1.16–2.16), 1.85 (95% CI 1.37–2.52) and 2.75 (95% CI 2.03–3.71) in the second, third and fourth quartile, respectively. Adjusting for NT-proBNPeGFR or inflammation (interleukin-6 and high-sensitive CRP) confirmed results. suPAR predicts all-cause and cardiovascular death over a period of ten years in persons undergoing coronary angiography, independent of the natriuretic peptide NT-proBNP, kidney function and of markers of systemic inflammation. Future investigation into a potential causal role of suPAR in cardiovascular disease is warranted.

Healthy lifestyles reduce suPAR and mortality in a Danish general population study

Background

The plasma level of the inflammatory biomarker soluble urokinase plasminogen activator receptor (suPAR) is a strong predictor of disease development and premature mortality in the general population. Unhealthy lifestyle habits such as smoking or unhealthy eating is known to elevate the suPAR level. We aimed to investigate whether change in lifestyle habits impact on the suPAR level, and whether the resultant levels are associated with mortality.

Results

Paired suPAR measurements from baseline- and the 5-year visit of the population-based Inter99 study were compared with the habits of diet, smoking, alcohol consumption, and physical activity. Paired suPAR measurements for 3225 individuals were analyzed by linear regression, adjusted for demographics and lifestyle habits. Compared to individuals with a healthy lifestyle, an unhealthy diet, low physical activity, and daily smoking were associated with a 5.9, 12.8, and 17.6% higher 5-year suPAR, respectively. During 6.1 years of follow-up after the 5-year visit, 1.6% of those with a low suPAR (mean 2.93 ng/ml) died compared with 3.8% of individuals with a high suPAR (mean 4.73 ng/ml), P <  0.001. In Cox regression analysis, adjusted for demographics and lifestyle, the hazard ratio for mortality per 5-year suPAR doubling was 2.03 (95% CI: 1.22-3.37).

Conclusion

Lifestyle has a considerable impact on suPAR levels; the combination of unhealthy habits was associated with 44% higher 5-year suPAR values and the 5-year suPAR was a strong predictor of mortality. We propose suPAR as a candidate biomarker for lifestyle changes as well as the subsequent risk of mortality.

Soluble urokinase plasminogen activator receptor in one-year prediction of major adverse cardiac events in patients after first myocardial infarction treated with primary percutaneous coronary intervention

INTRODUCTION

Soluble urokinase plasminogen activator receptor (suPAR) level reflects the general condition of the organism and was proved to give independent information in risk stratification of patients. The aim of this study was to assess the usefulness of suPAR in the prediction of adverse cardiac events in patients with first myocardial infarction (MI) undergoing primary percutaneous coronary intervention. Additionally, the diagnostic power of suPAR was assessed.

MATERIAL AND METHODS

One hundred and thirty-nine of 150 consecutive patients were included in the study. Serum suPAR level (ELISA, Virogates) as well as C-reactive protein (on admission and at discharge) and maximum troponin T (assessed from successive 6-hour periods of blood collection) were measured. In the 1-year follow-up study the following major adverse cardiac events were observed: myocardial infarction, revascularization, stroke and death.

RESULTS

Multi-variable analysis revealed prognostic usefulness only for suPAR and glomerular filtration rate: p < 0.0001 and p = 0.018; OR = 2.59 and OR = 0.98 respectively, with area under the curve in receiver operating characteristic analysis for both parameters simultaneously 0.89 (p < 0.0001). There was no correlation between suPAR level and the left ventricular dysfunction parameters or the MI type.

CONCLUSIONS

Soluble urokinase plasminogen activator receptor level appears to be an independent useful biomarker for the prediction of major adverse cardiac events early after first myocardial infarction. The biomarker's level seems to have more prognostic than diagnostic power.

Serum heart-type fatty acid-binding protein decreases and soluble isoform of suppression of tumorigenicity 2 increases significantly by long-term physical activity

The aim of this prospective study was to investigate the influence of long-term physical activity on biomarkers for myocyte ischemia (heart-type fatty acid-binding protein, H-FABP), matrix remodelling/vascular stress (soluble isoform of suppression of tumorigenicity 2, sST2) and inflammation (soluble urokinase-type plasminogen activator receptor, suPAR). In this prospective observational study 109 subjects were recruited, 98 completed the study. Subjects were asked to perform exercise within the calculated training pulse for 8 months. The performance gain was measured/quantified by bicycle stress tests at the beginning and end of the observation period. Twenty-seven subjects with a performance gain <2.9% were excluded. suPAR, H-FABP and sST2 were measured in serum at baseline and after 2, 4 and 8 months by ELISA. We found a significant decrease in H-FABP (1.86 (0.86) to 1.29 (0.98) ng/mL; p<0.01) and a significant increase in sST2 levels (6126 (2759) to 6919 (3720) pg/mL; p=0.045) during the observation period of 8 months while there was no remarkable change in suPAR levels. We interpret the activity-induced decrease in H-FABP as sign of lower subclinical myocardial ischemia and better perfusion, probably due to a more economic metabolization and electrolyte balance. The increase in sST2 might reflect physiological sports-induced vascular stress. As H-FABP and sST2 play an important role in the pathomechanism of ischemic cardiomyopathy (iCMP) further studies should investigate the influence of regular physical activity on these biomarkers in a population of patients with iCMP. TRIAL REGISTRATION NUMBER: NCT02097199.

Nontraditional Risk Factors in Cardiovascular Disease Risk Assessment: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Incorporating nontraditional risk factors may improve the performance of traditional multivariable risk assessment for cardiovascular disease (CVD).

OBJECTIVE

To systematically review evidence for the US Preventive Services Task Force on the benefits and harms of 3 nontraditional risk factors in cardiovascular risk assessment: the ankle-brachial index (ABI), high-sensitivity C-reactive protein (hsCRP) level, and coronary artery calcium (CAC) score.

DATA SOURCES

MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for studies published through May 22, 2017. Surveillance continued through February 7, 2018.

STUDY SELECTION

Studies of asymptomatic adults with no known cardiovascular disease.

DATA EXTRACTION AND SYNTHESIS

Independent critical appraisal and data abstraction by 2 reviewers.

MAIN OUTCOMES AND MEASURES

Cardiovascular events, mortality, risk assessment performance measures (calibration, discrimination, or risk reclassification), and serious adverse events.

RESULTS

Forty-three studies (N = 267 244) were included. No adequately powered trials have evaluated the clinical effect of risk assessment with nontraditional risk factors on patient health outcomes. The addition of the ABI (10 studies), hsCRP level (25 studies), or CAC score (19 studies) can improve both discrimination and reclassification; the magnitude and consistency of improvement varies by nontraditional risk factor. For the ABI, improvements in performance were the greatest for women, in whom traditional risk assessment has poor discrimination (C statistic change of 0.112 and net reclassification index [NRI] of 0.096). Results were inconsistent for hsCRP level, with the largest analysis (n = 166 596) showing a minimal effect on risk prediction (C statistic change of 0.0039, NRI of 0.0152). The largest improvements in discrimination (C statistic change ranging from 0.018 to 0.144) and reclassification (NRI ranging from 0.084 to 0.35) were seen for CAC score, although CAC score may inappropriately reclassify individuals not having cardiovascular events into higher-risk categories, as determined by negative nonevent NRI. Evidence for the harms of nontraditional risk factor assessment was limited to computed tomography imaging for CAC scoring (8 studies) and showed that radiation exposure is low but may result in additional testing.

CONCLUSIONS AND RELEVANCE

There are insufficient adequately powered clinical trials evaluating the incremental effect of the ABI, hsCRP level, or CAC score in risk assessment and initiation of preventive therapy. Furthermore, the clinical meaning of improvements in measures of calibration, discrimination, and reclassification risk prediction studies is uncertain.

Soluble Urokinase Plasminogen Activator Receptor (suPAR) and All-Cause and Cardiovascular Mortality in Diverse Hemodialysis Patients

Introduction

The soluble receptor of urokinase plasminogen activator (suPAR) is an innate immunity/inflammation biomarker predicting cardiovascular (CV) and non-CV events in various conditions, including type 2 diabetic patients on dialysis. However, the relationship between suPAR and clinical outcomes in the hemodialysis population at large has not been tested.

Methods

We measured plasma suPAR levels (R&D enzyme-linked immunosorbent assay [ELISA]) in 1038 hemodialysis patients with a follow-up of 2.9 years (interquartile range = 1.7−4.2) who were enrolled in the PROGREDIRE study, a cohort study involving 35 dialysis units in 2 regions in Southern Italy.

Results

suPAR was strongly (P < 0.001) and independently related to female gender (β = −0.160), age (β = 0.216), dialysis vintage (β = 0.264), CV comorbidities (β = 0.105), alkaline phosphatase (β = 0.136), albumin (β = −0.147), and body mass index (BMI; β = 0.174) (all P < 0.006). In fully adjusted analyses, suPAR tertiles predicted the risk of all-cause mortality (third tertile vs. first tertile hazard ratio (HR) = 1.91, 95% confidence interval (CI) = 1.47 – 2.48, P < 0.001), CV mortality (HR = 1.47, 95% CI = 1.03–2.09, P = 0.03), and non-CV mortality (HR = 1.94, 95% CI = 1.28–2.93, P = 0.002); these relationships were not modified by diabetes or other risk factors. suPAR added only modest prognostic risk discrimination and reclassification power for these outcomes to parsimonious models based on simple clinical variables.

Conclusion

In conclusion, suPAR robustly predicted all-cause and both CV and non-CV mortality in a large unselected hemodialysis population. Intervention studies are needed to definitively test the hypothesis that suPAR is causally implicated in clinical outcomes in this population.

Predicting Mortality in African Americans With Type 2 Diabetes Mellitus: Soluble Urokinase Plasminogen Activator Receptor, Coronary Artery Calcium, and High-Sensitivity C-Reactive Protein

BACKGROUND

Type 2 diabetes mellitus is a major risk factor for cardiovascular disease; however, outcomes in individual patients vary. Soluble urokinase plasminogen activator receptor (suPAR) is a bone marrow-derived signaling molecule associated with adverse cardiovascular and renal outcomes in many populations. We characterized the determinants of suPAR in African Americans with type 2 diabetes mellitus and assessed whether levels were useful for predicting mortality beyond clinical characteristics, coronary artery calcium (CAC), and high-sensitivity C-reactive protein (hs-CRP).

METHODS AND RESULTS

We measured plasma suPAR levels in 500 African Americans with type 2 diabetes mellitus enrolled in the African American-Diabetes Heart Study. We used Kaplan-Meier curves and Cox proportional hazards models adjusting for clinical characteristics, CAC, and hs-CRP to examine the association between suPAR and all-cause mortality. Last, we report the change in C-statistics comparing the additive values of suPAR, hs-CRP, and CAC to clinical models for prediction of mortality. The suPAR levels were independently associated with female sex, smoking, insulin use, decreased kidney function, albuminuria, and CAC. After a median 6.8-year follow-up, a total of 68 deaths (13.6%) were recorded. In a model incorporating suPAR, CAC, and hs-CRP, only suPAR was significantly associated with mortality (hazard ratio 2.66, 95% confidence interval 1.63-4.34). Addition of suPAR to a baseline clinical model significantly improved the C-statistic for all-cause death (Δ0.05, 95% confidence interval 0.01-0.10), whereas addition of CAC or hs-CRP did not.

CONCLUSIONS

In African Americans with type 2 diabetes mellitus, suPAR was strongly associated with mortality and improved risk discrimination metrics beyond traditional risk factors, CAC and hs-CRP. Studies addressing the clinical usefulness of measuring suPAR concentrations are warranted.

Telomerase RNA Component Genetic Variants Interact With the Mediterranean Diet Modifying the Inflammatory Status and its Relationship With Aging: CORDIOPREV Study

Background

Leukocyte telomere length (LTL) attrition has been associated with age-related diseases. Telomerase RNA Component (TERC) genetic variants have been associated with LTL; whereas fatty acids (FAs) can interact with genetic factors and influence in aging. We explore whether variability at the TERC gene locus interacts with FA profile and two healthy diets (low-fat diet vs Mediterranean diet [MedDiet]) modulating LTL, glucose metabolism, and inflammation status in coronary heart disease (CHD) patients.

Methods

Inflammation status (high-sensitivity C-reactive protein [hsCRP], glucose metabolism-glucose, insulin, and glycated hemoglobin [HbA1c], and homeostasis model assessment of insulin resistance [HOMA-IR]), LTL, FAs, and single nucleotide polymorphisms (SNPs) of the TERC gene (rs12696304, rs16847897, and rs3772190) were determined in 1,002 patients from the CORDIOPREV study (NCT00924937).

Results

We report an interaction of the TERC rs12696304 SNP with monounsaturated fatty acid (MUFA) affecting LTL (p interaction = .01) and hsCRP (p interaction = .03). Among individuals with MUFA levels above the median, CC individuals showed higher LTL and lower hsCRP than G-allele carriers. Moreover, MedDiet interacted with TERC rs12696304 SNP (p interaction = .03). Specifically, CC individuals displayed a greater decrease in hsCRP than G-allele carriers. These results were not adjusted for multiple statistical testing and p less than .05 was considered significant.

Conclusions

Our findings suggest that the TERC rs12696304 SNP interacts with MUFA improving inflammation status and telomere attrition related with CHD. Moreover, the MedDiet intervention improves the inflammatory profile in CC individuals compared with the G-allele carriers. These interactions could provide a right strategy for personalized nutrition in CHD patients.

Soluble Urokinase-type Plasminogen Activator Receptor Predicts All-cause 5-Year Mortality in Ischemic Stroke and TIA

AIM

We evaluated soluble urokinase-type plasminogen activator receptor (suPAR) levels in different stroke subtypes and assessed their prognostic value regarding 5-year outcomes.

MATERIALS AND METHODS

The study included 117 stroke patients (81 males; mean=age 61±11 years) with suspected cardioembolic stroke whose plasma suPAR concentration was assessed. Altogether, 20 (17.1%) patients suffered from stroke as a result of cardioembolism, 12 (10.3%) from large-artery atherosclerosis, 9 (7.7%) from small-vessel disease, 11 (9.4%) from both large-artery and cardioembolic etiology, and 65 (55.6%) had cryptogenic stroke. The mean follow-up period was 5 years.

RESULTS

suPAR concentration was higher in patients who suffered from stroke/transient ischemic attack due to large-artery atherosclerosis (3.2±0.9 ng/ml) compared to small-vessel disease (2.0±0.5 ng/ml, p<0.001). An elevated plasma suPAR concentration was associated with all-cause mortality during the follow-up period (p=0.003).

CONCLUSION

Elevated plasma suPAR concentrations predicted all-cause mortality during the 5-year follow-up after ischemic stroke. suPAR was not able to differentiate patients with cardioembolic stroke from those with other stroke types.

Soluble Urokinase-Type Plasminogen Activator Receptor Improves Risk Prediction in Patients With Chronic Heart Failure

OBJECTIVES

This study investigated the predictive value of soluble urokinase-type plasminogen activator receptor (suPAR) in patients with chronic heart failure (CHF).

BACKGROUND

SuPAR originates from proteolytic cleavage of the membrane-bound receptor from activated immune and endothelial cells and reflects the level of immune activation. As inflammation plays a crucial role in the complex pathophysiology of CHF, we hypothesized that suPAR might be a suitable prognostic biomarker in patients with CHF.

METHODS

SuPAR levels were determined in 319 patients with CHF admitted to our outpatient department for heart failure and in a second cohort consisting of 346 patients with CHF, for validation.

RESULTS

During a median follow-up time of 3.2 years, 119 patients (37.3%) died. SuPAR was a strong predictor of mortality with a crude hazard ratio (HR) per increase of 1 SD (HR per 1 SD) of 1.96 (95% confidence interval [CI]: 1.63 to 2.35; p < 0.001) in univariate analysis and remained significant after comprehensive multivariate adjustment with an adjusted HR per 1 SD of 1.38 (95% CI: 1.04 to 1.83; p = 0.026). SuPAR added prognostic value beyond the multivariate model indicated by improvements in C-statistics (area under the curve: 0.72 vs 0.74, respectively; p = 0.02), the category-free net reclassification index (24.9%; p = 0.032), and the integrated discrimination improvement (0.011; p = 0.05). Validation in the second cohort yielded consistent results.

CONCLUSIONS

SuPAR is a strong and independent predictor of mortality in patients with CHF, potentially suitable to refine risk assessment in this vulnerable group of patients. Our results emphasize the impact of immune activation on survival in patients with CHF.

Biomarkers to Predict Cardiovascular Death

This article reviews biomarkers that have been shown to identify subjects at increased risk for cardiovascular death within the general population, in those with established coronary artery disease, and in those with heart failure. Use of biomarkers for risk stratification for sudden cardiac death continues to evolve. It seems that a multimarker strategy for risk stratification using simple measures of circulating proteins and usual clinical risk factors, particularly in patients with known coronary artery disease, can be used to identify patients at near-term risk of death. Whether similar strategies in the general population will prove to be cost-effective needs to be investigated.

Pathway-Specific Aggregate Biomarker Risk Score Is Associated With Burden of Coronary Artery Disease and Predicts Near-Term Risk of Myocardial Infarction and Death

BACKGROUND

Inflammation, coagulation, and cell stress contribute to atherosclerosis and its adverse events. A biomarker risk score (BRS) based on the circulating levels of biomarkers C-reactive protein, fibrin degradation products, and heat shock protein-70 representing these 3 pathways was a strong predictor of future outcomes. We investigated whether soluble urokinase plasminogen activator receptor (suPAR), a marker of immune activation, is predictive of outcomes independent of the aforementioned markers and whether its addition to a 3-BRS improves risk reclassification.

METHODS AND RESULTS

C-reactive protein, fibrin degradation product, heat shock protein-70, and suPAR were measured in 3278 patients undergoing coronary angiography. The BRS was calculated by counting the number of biomarkers above a cutoff determined using the Youden's index. Survival analyses were performed using models adjusted for traditional risk factors. A high suPAR level ≥3.5 ng/mL was associated with all-cause death and myocardial infarction (hazard ratio, 1.83; 95% confidence interval, 1.43-2.35) after adjustment for risk factors, C-reactive protein, fibrin degradation product, and heat shock protein-70. Addition of suPAR to the 3-BRS significantly improved the C statistic, integrated discrimination improvement, and net reclassification index for the primary outcome. A BRS of 1, 2, 3, or 4 was associated with a 1.81-, 2.59-, 6.17-, and 8.80-fold increase, respectively, in the risk of death and myocardial infarction. The 4-BRS was also associated with severity of coronary artery disease and composite end points.

CONCLUSIONS

SuPAR is independently predictive of adverse outcomes, and its addition to a 3-BRS comprising C-reactive protein, fibrin degradation product, and heat shock protein-70 improved risk reclassification. The clinical utility of using a 4-BRS for risk prediction and management of patients with coronary artery disease warrants further study.

How biomarkers reflect the prognosis and treatment of necrotising soft tissue infections and the effects of hyperbaric oxygen therapy: the protocol of the prospective cohort PROTREAT study conducted at a tertiary hospital in Copenhagen, Denmark

INTRODUCTION

Not enough is known regarding the prognosis and treatment of necrotising soft tissue infections (NSTIs). Mortality has been shown to be 25%-35%, with survivors coping with amputations and prolonged rehabilitation. This study will evaluate soluble urokinase-type plasminogen activator receptor (suPAR) as a possible prognostic marker of NSTI severity and mortality, as well as whether hyperbaric oxygen therapy (HBOT) can modulate markers of endothelial damage during NSTI. We hypothesise that in patients with NSTI, suPAR can provide prognostic risk assessment on hospital admission and that HBOT can reduce the endothelial damage that these patients are exposed to.

METHODS AND ANALYSIS

This is a prospective observational study. Biomarkers will be measured in 150 patients who have been diagnosed with NSTI. On admission, baseline blood samples will be obtained. Following surgery and HBOT, daily blood samples will be obtained in order to measure endothelial and prognostic biomarkers (soluble thrombomodulin, syndecan-1, sE-selectin, vascular endothelial (VE)-cadherin, protein C and suPAR levels). Clinical data will be acquired during the first 7 days of stay in the intensive care unit. The primary outcomes in studies I and II will be endothelial biomarker levels after HBOT, and in study III suPAR levels as a marker of disease prognosis and severity.

ETHICS AND DISSEMINATION

The study has been approved by the Regional Scientific Ethical Committee of Copenhagen (H-16021845) and the Danish Data Protection Agency (RH-2016-199). Results will be presented at national and international conferences and published in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier NCT03147352. (Pre-results).

Soluble Urokinase Plasminogen Activator Receptor and the Risk of Coronary Artery Disease in Young Chinese Patients

Background

Soluble urokinase plasminogen activator receptor (suPAR) is a novel marker of chronic inflammation and is considered to be a risk factor for coronary artery disease (CAD) in Caucasians. This study investigated the role of suPAR in young Chinese patients with CAD.

Methods

The study involved a total of 196 consecutive young (age ≤ 55 years) patients with angiographically proven CAD and 188 age-matched non-CAD individuals as controls. Traditional risk factors were evaluated using conventional assays, and levels of suPAR were measured by sandwich enzyme-linked immunosorbent assays.

Results

Levels of suPAR were significantly correlated with age (r = 0.20, P = 0.04), smoking (r = 0.33, P = 0.008), body mass index (r = 0.21, P = 0.03), and high-sensitivity C-reactive protein (hs-CRP; r = 0.31, P = 0.01). Multivariate logistic regression analysis showed that male sex (odds ratio (OR) = 3.12; 95% confidence interval (CI) = 1.18–8.25, P = 0.02), smoking (OR = 3.41, 95% CI = 1.55–7.50, P = 0.002), triglyceride (OR = 1.89, 95% CI = 1.10–3.25, P = 0.02), high-sensitivity C-reactive protein (OR = 1.24, 95% CI = 1.02–0.03, P = 0.03), and suPAR (OR = 1.37, 95% CI = 1.09–1.72, P = 0.007) were independently associated with CAD risk in young patients.

Conclusions

SuPAR is a novel independent risk factor for CAD in young Chinese patients. Further studies evaluating the effect of anti-inflammatory treatment on the suPAR levels and the risk of CAD are needed.

Soluble Urokinase Plasminogen Activator Receptor and Outcomes in Patients with Diabetes on Hemodialysis

BACKGROUND AND OBJECTIVES

Soluble urokinase plasminogen activator receptor is a novel biomarker strongly predictive of cardiovascular outcomes implicated in the pathogenesis of kidney disease. Soluble urokinase plasminogen activator receptor levels, however, correlate with declining kidney function. It is unclear whether soluble urokinase plasminogen activator receptor levels remain associated with outcomes in patients with ESRD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We measured plasma soluble urokinase plasminogen activator receptor levels in 1175 patients (mean age =66±8 years old, 54% men) with type 2 diabetes mellitus on hemodialysis participating in the German Diabetes and Dialysis Study followed for a median of 4 years for outcomes including all-cause death, cardiovascular events, and infection-related mortality. Survival analysis was performed using stepwise Cox proportional hazards models adjusted for potential confounders. Also, adjustments were made for inflammatory markers (C-reactive protein and leukocyte count) and the oxidative stress marker asymmetric dimethyl arginine to investigate potential mediators of the relationship between soluble urokinase plasminogen activator receptor and outcomes.

RESULTS

Median soluble urokinase plasminogen activator receptor levels were 10,521 pg/ml (interquartile range, 9105-12,543 pg/ml). When stratified by tertiles, patients with soluble urokinase plasminogen activator receptor >11,633 pg/ml (third tertile) had adjusted 1.6-fold higher mortality (hazard ratio, 1.60; 95% confidence interval, 1.27 to 2.03) compared with those with low soluble urokinase plasminogen activator receptor <9599 pg/ml (first tertile). Risks of sudden death and stroke were higher (adjusted hazard ratio, 1.98; 95% confidence interval, 1.27 to 3.09 and adjusted hazard ratio, 1.74; 95% confidence interval, 1.05 to 2.90, respectively), together accounting for higher incidence of cardiovascular events (adjusted hazard ratio, 1.48; 95% confidence interval, 1.15 to 1.89). Associations with outcomes persisted after adjusting for C-reactive protein, leukocyte count, and asymmetric dimethyl arginine. Addition of soluble urokinase plasminogen activator receptor to a risk factor model modestly improved risk discrimination for all-cause death (ΔC statistic, 0.02; 95% confidence interval, 0.00 to 0.03) and cardiovascular events (ΔC statistic, 0.02; 95% confidence interval, 0.00 to 0.05).

CONCLUSIONS

The association of soluble urokinase plasminogen activator receptor levels with outcomes persists in patients on hemodialysis. Additional study is warranted to characterize the underlying pathways of that association, which may yield opportunities to develop new therapeutic strategies.

Elevated Soluble Urokinase Plasminogen Activator Receptor and Proenkephalin Serum Levels Predict the Development of Acute Kidney Injury after Cardiac Surgery

Acute kidney injury (AKI) develops in up to 40% of patients after cardiac surgery. The soluble urokinase plasminogen activator receptor (suPAR) has been identified as a biomarker for incident chronic kidney disease (CKD). Proenkephalin (proENK) also has been shown to be a biomarker for renal dysfunction. We hypothesized that pre-surgery suPAR and proENK levels might predict AKI in patients undergoing cardiac surgery. Consecutive patients (n = 107) undergoing elective cardiac surgery were studied prospectively. Clinical data, laboratory parameters, suPAR and proENK serum levels were assessed before operation, after operation and days one and four post-operatively. A total of 21 (19.6%) patients developed AKI within the first four days after elective surgery. Serum levels of suPAR and proENK, but not of creatinine, were significantly higher before surgery in these patients compared to those patients without AKI. This difference remained significant for suPAR, if patients with or without AKI were matched for risk factors (hypertension, diabetes, CKD). If cardiac surgery patients with pre-existing CKD (n = 10) were excluded, only pre-operative suPAR but not proENK serum levels remained significantly elevated in patients with subsequent AKI. Thus, our findings indicate that suPAR may be a predictive biomarker for AKI in the context of cardiac surgery, even in patients without underlying CKD.

Recent Treatment Advances and New Trials in Adult Nephrotic Syndrome

The etiology of nephrotic syndrome is complex and ranges from primary glomerulonephritis to secondary forms. Patients with nephrotic syndrome often need immunosuppressive treatment with its side effects and may progress to end stage renal disease. This review focuses on recent advances in the treatment of primary causes of nephrotic syndrome (idiopathic membranous nephropathy (iMN), minimal change disease (MCD), and focal segmental glomerulosclerosis (FSGS)) since the publication of the KDIGO guidelines in 2012. Current treatment recommendations are mostly based on randomized controlled trials (RCTs) in children, small RCTs, or case series in adults. Recently, only a few new RCTs have been published, such as the Gemritux trial evaluating rituximab treatment versus supportive antiproteinuric and antihypertensive therapy in iMN. Many RCTs are ongoing for iMN, MCD, and FSGS that will provide further information on the effectiveness of different treatment options for the causative disease. In addition to reviewing recent clinical studies, we provide insight into potential new targets for the treatment of nephrotic syndrome from recent basic science publications.

Cardiovascular Disease Biomarkers and suPAR in Predicting Decline in Renal Function: A Prospective Cohort Study

INTRODUCTION

Soluble urokinase-type plasminogen activator receptor (suPAR) strongly predicts outcomes and incident chronic kidney disease (CKD) in patients with cardiovascular disease (CVD). Whether the association between suPAR and CKD is a reflection of its overall association with chronic inflammation and poor CVD outcomes is unclear. We examined whether CVD biomarkers, including high-sensitivity C-reactive protein (hs-CRP), fibrin-degradation products (FDPs), heat-shock protein 70 (HSP-70), and high-sensitivity troponin I (hs-TnI) were associated with a decline in kidney function in the Emory Cardiovascular Biobank cohort, in which suPAR levels were shown to be predictive of both incident CKD and CVD outcomes.

METHODS

We measured suPAR, hs-CRP, HSP-70, FDP, and hs-TnI plasma levels in 3282 adults (mean age 63 years, 64% male, 75% estimated glomerular filtration rate [eGFR] >60 ml/min per 1.73 m2). Glomerular filtration rate was estimated using Chronic Kidney Disease-Epidemiology Collaboration (eGFR) at enrollment (n = 3282) and follow-up (n = 2672; median 3.5 years). Urine protein by dipstick at baseline was available for 1335 subjects.

RESULTS

There was a weak correlation among biomarkers (r range: 0.17-0.28). hs-CRP, FDPs, hs-TnI, and suPAR were independently associated with baseline eGFR and proteinuria. The median yearly decline in eGFR was -0.6 ml/min per 1.73 m2. hs-CRP (β: -0.04; P = 0.46), FDPs (β: -0.13; P = 0.08), HSP-70 (β: 0.05; P = 0.84), or hs-TnI (β: -0.01; P = 0.76) were associated with eGFR decline. suPAR remained predictive of eGFR decline even after adjusting for all biomarkers.

DISCUSSION

hs-CRP, FDP, HSP-70, and hs-TnI were not associated with eGFR decline. The specific association of suPAR with eGFR decline supported its involvement in pathways specific to the pathogenesis of kidney disease.

Effects of Acute Exercise on Circulating Soluble Form of the Urokinase Receptor in Patients With Major Depressive Disorder

Inflammation has been proposed to play a role in the generation of depressive symptoms. Previously, we demonstrated that patients with major depressive disorder (MDD) have increased plasma levels of the soluble form of the urokinase receptor (suPAR), a marker for low-grade inflammation. The aim of this study was to test the hypothesis that acute exercise would induce inflammatory response characterized by increased suPAR and elucidate whether patients with MDD display altered levels of suPAR in response to acute exercise. A total of 17 patients with MDD and 17 controls were subjected to an exercise challenge. Plasma suPAR (P-suPAR) was analyzed before, during, and after exercise. There was a significantly higher baseline P-suPAR in the patients with MDD, and the dynamic changes of P-suPAR during the exercise were significantly lower in the patients with MDD, compared with the controls. This study supports the hypothesis that an activation of systemic inflammatory processes, measured as elevated P-suPAR, is involved in the pathophysiology of depression. The study concludes that P-suPAR is influenced by acute exercise, most likely due to release from activated neutrophils.

Serum Soluble Urokinase-Type Plasminogen Activator Receptor Is Associated with Low Left Ventricular Ejection Fraction and Elevated Plasma Brain-Type Natriuretic Peptide Level

BACKGROUND

Recent studies have suggested that soluble urokinase plasminogen activator receptor (suPAR), a biomarker of subclinical levels of inflammation, is significantly correlated with cardiovascular events.

PURPOSE

We investigated the association between suPAR and left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), and plasma B-type natriuretic peptide (BNP) among cardiac inpatients.

METHODS AND RESULTS

In total, 242 patients (mean age 71.3 ± 9.8 years; 70 women) admitted to the cardiology department were enrolled in the study. suPAR was significantly correlated with LVEF (R = -0.24, P<0.001), LVMI (R = 0.16, P = 0.014) and BNP (R = 0.46, P<0.001). In logistic regression analysis, the highest suPAR tertile (> 3236 pg/mL) was associated with low LVEF (< 50%) and elevated BNP (> 300 pg/mL) with an odds ratio of 3.84 (95% confidence interval [CI], 1.22-12.1) and 5.36 (95% CI, 1.32-21.8), respectively, after adjusting for age, sex, log-transformed estimated glomerular filtration rate (log(eGFR)), C-reactive protein, and diuretic use. The association between suPAR and LVMI was not statistically significant. In multivariate receiver operating characteristic analysis, addition of log(suPAR) to the combination of age, sex, log(eGFR) and CRP incrementally improved the prediction of low LVEF (area under the curve [AUC], 0.827 to 0.852, P = 0.046) and BNP ≥ 300 pg/mL (AUC, 0.869 to 0.906; P = 0.029).

CONCLUSIONS

suPAR was associated with low LVEF and elevated BNP, but not with left ventricular hypertrophy, independent of CRP, renal function, and diuretic use among cardiac inpatients who were not undergoing chronic hemodialysis.

Soluble urokinase plasminogen activation receptor--An emerging new biomarker of cardiovascular disease and critical illness

Soluble urokinase plasminogen activation receptor (suPAR) is an emerging new biomarker, which has been shown to not only correlate with traditional biomarkers but also outperform CRP at prognosticating CVD. More clinical trials on suPAR is in the future research agenda.

Soluble Urokinase Receptor and the Kidney Response in Diabetes Mellitus

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD) worldwide. DN typically manifests by glomerular hyperfiltration and microalbuminuria; then, the disease progresses to impaired glomerular filtration rate, which leads to ESRD. Treatment options for DN include the strict control of blood glucose levels and pressure (e.g., intraglomerular hypertension). However, the search for novel therapeutic strategies is ongoing. These include seeking specific molecules that contribute to the development and progression of DN to potentially interfere with these "molecular targets" as well as with the cellular targets within the kidney such as podocytes, which play a major role in the pathogenesis of DN. Recently, podocyte membrane protein urokinase receptor (uPAR) and its circulating form (suPAR) are found to be significantly induced in glomeruli and sera of DN patients, respectively, and elevated suPAR levels predicted diabetic kidney disease years before the occurrence of microalbuminuria. The intent of this review is to summarize the emerging evidence of uPAR and suPAR in the clinical manifestations of DN. The identification of specific pathways that govern DN will help us build a more comprehensive molecular model for the pathogenesis of the disease that can inform new opportunities for treatment.

Renin angiotensin system blockade reduces urinary levels of soluble urokinase plasminogen activator receptor (suPAR) in patients with type 2 diabetes

Soluble urokinase plasminogen activator receptor (suPAR) is associated with faster decline in kidney function and the pathogenesis of diabetic nephropathy. However, little is known about the impact of treatment on plasma and urinary levels of suPAR. We aimed to investigate the impact of renin angiotensin system (RAS) single and dual blockade on suPAR levels in patients with type 2 diabetes and albuminuria. We conducted a post-hoc analysis of a randomized controlled crossover trial. Urine and plasma samples were analyzed for suPAR levels. The placebo period was considered reference and all treatment periods were compared to placebo. Patients (n = 22) were treated for 2-month periods with either placebo, irbesartan 300 mg once daily, aliskiren 300 mg once daily or irbesartan/aliskiren combination in random order. Placebo geometric mean plasma (SEM) levels of suPAR were 3.3 ng/mL (1.1) and urine levels were 4.0 ng/mL (1.1). None of the treatments had significant effects on plasma levels of suPAR compared to placebo. Compared to placebo, irbesartan and combination treatment decreased urinary levels of suPAR significantly (-1.3 ng/mL), while aliskiren did not. In patients with type 2 diabetes urinary levels of suPAR were reduced during RAS blockade treatment, which may contribute to renoprotection.

Soluble urokinase plasminogen activator receptor (suPAR) in acute care: a strong marker of disease presence and severity, readmission and mortality. A retrospective cohort study

Objective

Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory biomarker associated with presence and progression of disease and with increased risk of mortality. We aimed to evaluate the unspecific biomarker suPAR as a prognostic marker in patients admitted to acute care.

Methods

This registry-based retrospective cohort study included 4343 consecutively admitted patients from the Acute Medical Unit at a large Danish university hospital. Time to readmission and death were analysed by multiple Cox regression. Results were reported as HRs for 30-day and 90-day follow-up.

Results

During 30-day follow-up, 782 patients (18.0%) were readmitted and 224 patients (5.2%) died. Comparing 30-day readmission and mortality between patients in the highest and lowest suPAR quartiles yielded HRs of 2.11 (95% CI 1.70 to 2.62) and 4.11 (95% CI 2.46 to 6.85), respectively, when adjusting for age, sex, Charlson score and C reactive protein. Area under the curve for receiver operating characteristics curve analysis of suPAR for 30-day mortality was 0.84 (95% CI 0.81 to 0.86). Furthermore, in the entire cohort, women had slightly higher suPAR compared with men, and suPAR was associated with age, admission time, admission to intensive care unit and Charlson score.

Conclusions

In this large unselected population of acute medical patients, suPAR is strongly associated with disease severity, readmission and mortality after adjusting for all other risk factors, indicating that suPAR adds information to established prognostic indicators. While patients with low suPAR levels have low risk of readmission and mortality, patients with high suPAR levels have a high risk of adverse events.

Introduction of a prognostic biomarker to strengthen risk stratification of acutely admitted patients: rationale and design of the TRIAGE III cluster randomized interventional trial

Background

Several biomarkers have shown to carry prognostic value beyond current triage algorithms and may aid in initial risk stratification of patients in the emergency department (ED). It has yet to be established if information provided by biomarkers can be used to prevent serious complications or deaths. Our aim is to determine whether measurement of the blood level of the biomarker soluble urokinase plasminogen activator receptor (suPAR) can enhance early risk stratification leading to reduced mortality, lower rate of complications, and improved patient flow in acutely admitted adult patients at the ED. The main hypothesis is that the availability of suPAR can reduce all-cause mortality, assessed at least 10 months after admission, by drawing attention towards patients with an unrecognized high risk, leading to improved diagnostics and treatment.

Methods

The study is designed as a cross-over cluster randomized interventional trial. SuPAR is measured within 2 h after admission and immediately reported to the treating physicians in the ED. All ED physicians are educated in the prognostic capabilities of suPAR prior to the inclusion period. The inclusion period began January 11^th 2016 and ends June 6^th 2016. The study aims to include 10.000 patients in both the interventional and control arm. The results will be presented in 2017.

Discussion

The present article aims to describe the design and rationale of the TRIAGE III study that will investigate whether the availability of prognostic information can improve outcome in acutely admitted patients. This might have an impact on health care organization and decision-making.

Trial registration

The trial is registered at clinicaltrials.gov (ID NCT02643459, November 13, 2015) and at the Danish Data Protection agency (ID HGH-2015-042 I-Suite no. 04087).

Increased circulating soluble urokinase-type plasminogen activator receptor (suPAR) levels in patients with slow coronary flow

Introduction

Slow coronary flow (SCF) is an angiographic phenomenon characterized by delayed opacification of epicardial coronary arteries without an obstructive coronary disease. Serum soluble urokinase-type plasminogen activator receptor (suPAR) levels seem closely related to atherosclerosis due to increased inflammation and prothrombotic state. We studied whether circulating suPAR is related to SCF.

Material and methods

The present study was cross-sectional and observational. It included 75 individuals who underwent coronary angiography with suspected CAD and had angiographically normal coronary arteries of varying coronary flow rates. The relationship between suPAR, C-reactive protein (CRP) and SCF was investigated. Forty patients with isolated SCF (mean age: 46.0 ±4.14 years) and 35 age- and gender-matched control participants with normal coronary flow (NCF) and normal coronary arteries (NCA) (mean age: 46.0 ±5.7 years) were included in the study. We used logistic regression analysis to determine the predictors of SCF.

Results

The clinical characteristics were not statistically significantly different between SCF and NCA groups. Serum suPAR level was significantly higher in the SCF group than the control group (2.5–5.4 ng/ml vs. 0.1–1.4 ng/ml; p < 0.001). Also the serum CRP level was higher in the CSF group than the control group (1.57 ±0.43 mg/l vs. 0.53 ±0.23 mg/l; p < 0.001).

Conclusions

This study revealed significantly increased serum suPAR levels in patients with SCF. Although we cannot draw conclusions on the underlying pathological process of SCF, we believe that these findings may be pioneering for further studies investigating the specific roles of circulating suPAR in the SCF phenomenon in the coronary vasculature.

suPAR level is associated with myocardial impairment assessed with advanced echocardiography in patients with type 1 diabetes with normal ejection fraction and without known heart disease or end-stage renal disease

AIM

Heart disease is a common fatal diabetes-related complication. Early detection of patients at particular risk of heart disease is of prime importance. Soluble urokinase plasminogen activator receptor (suPAR) is a novel biomarker for development of cardiovascular disease. We investigate if suPAR is associated with early myocardial impairment assessed with advanced echocardiographic methods.

METHODS

In an observational study on 318 patients with type 1 diabetes without known heart disease and with normal left ventricular ejection fraction (LVEF) (biplane LVEF >45%), we performed conventional, tissue Doppler and speckle tracking echocardiography, and measured plasma suPAR levels. Associations between myocardial function and suPAR levels were studied in adjusted models including significant covariates.

RESULTS

Patients were 55±12 years (mean±s.d.) and 160 (50%) males. Median (interquartile range) suPAR was 3.4 (1.7) ng/mL and LVEF was 58±5%. suPAR levels were not associated with LVEF (P=0.11). In adjusted models, higher suPAR levels were independently associated with both impaired systolic function assessed with global longitudinal strain (GLS) and tissue velocity s', and with impaired diastolic measures a' and e'/a' (all P=0.034). In multivariable analysis including cardiovascular risk factors and both systolic and diastolic measures (GLS and e'/a'), both remained independently associated with suPAR levels (P=0.012).

CONCLUSIONS

In patients with type 1 diabetes with normal LVEF and without known heart disease, suPAR is associated with early systolic and diastolic myocardial impairment. Our study implies that both suPAR and advanced echocardiography are useful diagnostic tools for identifying patients with diabetes at risk of future clinical heart disease, suited for intensified medical therapy.

Circulating Permeability Factors in Primary Focal Segmental Glomerulosclerosis: A Review of Proposed Candidates

Primary focal segmental glomerulosclerosis (FSGS) is a major cause of the nephrotic syndrome and often leads to end-stage renal disease. This review focuses on circulating permeability factors in primary FSGS that have been implicated in the pathogenesis for a long time, partly due to the potential recurrence in renal allografts within hours after transplantation. Recently, three molecules have been proposed as a potential permeability factor by different groups: the soluble urokinase plasminogen activator receptor (suPAR), cardiotrophin-like cytokine factor-1 (CLCF-1), and CD40 antibodies. Both CLCF-1 and CD40 antibodies have not been validated by independent research groups yet. Since the identification of suPAR, different studies have questioned the validity of suPAR as a biomarker to distinguish primary FSGS from other proteinuric kidney diseases as well as suPAR's pathogenic role in podocyte damage. Researchers have suggested that cleaved molecules of suPAR have a pathogenic role in FSGS but further studies are needed to determine this role. In future studies, proposed standards for the research of the permeability factor should be carefully followed. The identification of the permeability factor in primary FSGS would be of great clinical relevance as it could influence potential individual treatment regimen.

Plasma suPAR is lowered by smoking cessation: a randomized controlled study

BACKGROUND

Soluble urokinase plasminogen activator receptor (suPAR) is a stable inflammatory biomarker. In patients, suPAR is a marker of disease presence, severity and prognosis. In the general population, suPAR is predictive of disease development, such as diabetes and cardiovascular disease and, in smokers, predictive of long-term lung cancer development. Whether smoking cessation impacts the suPAR level is unknown.

MATERIALS AND METHODS

Forty-eight smokers were randomized into three groups of 16: (i) continued to smoke 20 cigarettes per day, (ii) refrained from smoking and used transdermal nicotine patches and (iii) refrained from smoking and used placebo patches. Nonsmokers were included for comparison. suPAR and C-reactive protein (CRP) levels were measured by ELISA.

RESULTS

At baseline, the suPAR level was significantly higher in the 48 smokers (median 3·2 ng mL, IQR (2·5-3·9)) than in 46 never smokers (1·9 ng/mL (1·7-2·2)). In smokers randomized to smoking cessation, suPAR levels after 4 weeks of stopping were decreased and no longer significantly different from the never smokers values. SuPAR decreased in both those who received a placebo as well as nicotine patch. Interestingly, those with the highest suPAR level at time of smoking were also those with the highest level of suPAR after smoking cessation. In contrast, smoking or smoking cessation had no influence on CRP levels.

CONCLUSION

Our study suggests that the suPAR level may aid to personalize the risk of smoking by identifying those smokers with the highest risk of developing disease and who may have the most benefit of smoking cessation.

Soluble Urokinase Receptor and Chronic Kidney Disease

BACKGROUND

Relatively high plasma levels of soluble urokinase-type plasminogen activator receptor (suPAR) have been associated with focal segmental glomerulosclerosis and poor clinical outcomes in patients with various conditions. It is unknown whether elevated suPAR levels in patients with normal kidney function are associated with future decline in the estimated glomerular filtration rate (eGFR) and with incident chronic kidney disease.

METHODS

We measured plasma suPAR levels in 3683 persons enrolled in the Emory Cardiovascular Biobank (mean age, 63 years; 65% men; median suPAR level, 3040 pg per milliliter) and determined renal function at enrollment and at subsequent visits in 2292 persons. The relationship between suPAR levels and the eGFR at baseline, the change in the eGFR over time, and the development of chronic kidney disease (eGFR <60 ml per minute per 1.73 m(2) of body-surface area) were analyzed with the use of linear mixed models and Cox regression after adjustment for demographic and clinical variables.

RESULTS

A higher suPAR level at baseline was associated with a greater decline in the eGFR during follow-up; the annual change in the eGFR was -0.9 ml per minute per 1.73 m(2) among participants in the lowest quartile of suPAR levels as compared with -4.2 ml per minute per 1.73 m(2) among participants in the highest quartile (P<0.001). The 921 participants with a normal eGFR (≥ 90 ml per minute per 1.73 m(2)) at baseline had the largest suPAR-related decline in the eGFR. In 1335 participants with a baseline eGFR of at least 60 ml per minute per 1.73 m(2), the risk of progression to chronic kidney disease in the highest quartile of suPAR levels was 3.13 times as high (95% confidence interval, 2.11 to 4.65) as that in the lowest quartile.

CONCLUSIONS

An elevated level of suPAR was independently associated with incident chronic kidney disease and an accelerated decline in the eGFR in the groups studied. (Funded by the Abraham J. and Phyllis Katz Foundation and others.).

Soluble Urokinase Receptor and Chronic Kidney Disease

BACKGROUND

Relatively high plasma levels of soluble urokinase-type plasminogen activator receptor (suPAR) have been associated with focal segmental glomerulosclerosis and poor clinical outcomes in patients with various conditions. It is unknown whether elevated suPAR levels in patients with normal kidney function are associated with future decline in the estimated glomerular filtration rate (eGFR) and with incident chronic kidney disease.

METHODS

We measured plasma suPAR levels in 3683 persons enrolled in the Emory Cardiovascular Biobank (mean age, 63 years; 65% men; median suPAR level, 3040 pg per milliliter) and determined renal function at enrollment and at subsequent visits in 2292 persons. The relationship between suPAR levels and the eGFR at baseline, the change in the eGFR over time, and the development of chronic kidney disease (eGFR <60 ml per minute per 1.73 m(2) of body-surface area) were analyzed with the use of linear mixed models and Cox regression after adjustment for demographic and clinical variables.

RESULTS

A higher suPAR level at baseline was associated with a greater decline in the eGFR during follow-up; the annual change in the eGFR was -0.9 ml per minute per 1.73 m(2) among participants in the lowest quartile of suPAR levels as compared with -4.2 ml per minute per 1.73 m(2) among participants in the highest quartile (P<0.001). The 921 participants with a normal eGFR (≥ 90 ml per minute per 1.73 m(2)) at baseline had the largest suPAR-related decline in the eGFR. In 1335 participants with a baseline eGFR of at least 60 ml per minute per 1.73 m(2), the risk of progression to chronic kidney disease in the highest quartile of suPAR levels was 3.13 times as high (95% confidence interval, 2.11 to 4.65) as that in the lowest quartile.

CONCLUSIONS

An elevated level of suPAR was independently associated with incident chronic kidney disease and an accelerated decline in the eGFR in the groups studied. (Funded by the Abraham J. and Phyllis Katz Foundation and others.).

Soluble urokinase plasminogen activator receptor (suPAR) is a novel, independent predictive marker of myocardial infarction in HIV-1-infected patients: a nested case-control study

Objectives

Patients infected with HIV are at increased risk of myocardial infarction (MI). Increased plasma levels of the inflammatory biomarker soluble urokinase plasminogen activator receptor (suPAR) have been associated with increased risk of cardiovascular diseases (CVD), including MI in the general population. We tested suPAR as a predictive biomarker of MI in HIV‐1‐infected individuals.

Methods

suPAR levels were investigated in a nested case‐control study of 55 HIV‐1‐infected cases with verified first‐time MI and 182 HIV‐1‐infected controls with no known CVD. Controls were matched for age, gender, duration of antiretroviral therapy (ART), smoking and no known CVD. suPAR was measured in the four plasma samples available for each patient at different time‐points; 1, Before initiation of ART; 2, 3 months after initiation of ART; 3, 1 year before the case's MI; and 4, The last sample available before the case's MI.

Results

In unadjusted conditional regression analysis, higher levels of suPAR were associated with a significant increase in risk of MI at all time‐points. Patients in the third and fourth suPAR quartiles had a three‐ to 10‐fold higher risk of MI compared to patients in the lowest suPAR quartile at all time‐points. suPAR remained a strong significant predictor of MI, when adjusting for HIV‐1 RNA, total cholesterol, triglycerides and high‐density lipoprotein.

Conclusion

Elevated suPAR levels were associated with increased risk of MI in HIV‐infected patients, suggesting that suPAR could be a useful biomarker for prediction of first‐time MI in this patient group, even years before the event.