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

The Soluble Urokinase Plasminogen Activator Receptor as a Severity Biomarker in Children With Acute COVID-19 or Multisystem Inflammatory Syndrome

BACKGROUND

Elevated soluble urokinase plasminogen activator receptor (suPAR) has been associated with a poor prognosis in serious infections. The aim of this study was to evaluate the clinical value of suPAR in children with acute coronavirus disease 2019 (COVID-19) or multisystem inflammatory syndrome (MIS-C).

METHODS

Serum suPAR was measured using the suPARnostic AUTO Flex enzyme-linked immunosorbent assay in hospitalized children with COVID-19, MIS-C, bacterial pneumonia, and healthy controls.

RESULTS

A total of 211 children with a mean (±SD) age of 6.9 ± 4.96 years were tested; with COVID-19: 59 (28%), MIS-C: 36 (17%), pneumonia: 78 (37%) and healthy controls: 38 (18%). In the acute phase, the levels of suPAR (mean ± SD) were: MIS-C: 8.11 ± 2.80 ng/mL, COVID-19: 4.91 ± 1.90 ng/mL, pneumonia: 4.25 ± 1.44 ng/mL and controls: 2.09 ± 0.47 ng/mL ( P < 0.001). Children with acute COVID-19 and a severe or moderate clinical presentation had higher values than those with mild symptoms: 5.79 ± 1.58 versus 5.40 ± 1.94 versus 3.19 ± 0.73 ng/mL, respectively ( P < 0.001). In the MIS-C group, children hospitalized in the intensive care unit and in need of mechanical ventilation had higher suPAR than those who were not admitted to an intensive care unit: 9.32 ± 3.06 versus 7.13 ± 2.19 ng/mL, respectively ( P = 0.023). In children with COVID-19 or MIS-C, a correlation was detected between suPAR values and length of hospitalization ( rs = 0.418, P < 0.001).

CONCLUSIONS

The findings suggest that suPAR may be a valuable biomarker of disease severity in children with COVID-19 or MIS-C. This could facilitate the identification of children in need of intensive anti-inflammatory treatment, as it has been shown in adults with severe COVID-19.

Intestinal Permeability, Gut Inflammation, and Gut Immune System Response Are Linked to Aging-Related Changes in Gut Microbiota Composition: A Study in Female Mice

Aging entails changes at the cellular level that increase the risk of various pathologies. An association between gut microbiota and age-related diseases has also been attributed. This study aims to analyze changes in fecal microbiota composition and their association with genes related to immune response, gut inflammation, and intestinal barrier impairment. Fecal samples of female mice at different ages (2 months, 6 months, 12 months, and 18 months) and gene expression in colon tissue were analyzed. Results showed that the older mice group had a more diverse microbiota than the younger group. Additionally, the abundance of Cyanobacteria, Proteobacteria, Flavobacteriaceae, Bacteroides, Parabacteroides, Prevotellaceae_UCG-001, Akkermansia, and Parabacteroides goldsteinii increased with age. In contrast, there was a notable decline in Clostridiaceae, Lactobacillaceae, Monoglobaceae, Ligilactobacillus, Limosilactobacillus, Mucispirillum, and Bacteroides faecichinchillae. These bacteria imbalances were positively correlated with increased inflammation markers in the colon, including Tnf-α, Ccl2, and Ccl12, and negatively with the expression of tight junction genes (Jam2, Tjp1, and Tjp2), as well as immune response genes (Cd4, Cd72, Tlr7, Tlr12, and Lbp). In conclusion, high levels of diversity did not result in improved health in older mice; however, the imbalance in bacteria abundance that occurs with aging might contribute to immune senescence, inflammation, and leaky gut disease.

Mesenchymal stem cell-derived exosomes: a promising alternative in the therapy of preeclampsia

Preeclampsia (PE) is a common morbid complication during pregnancy, affecting 2%-8% of pregnancies globally and posing serous risks to the health of both mother and fetus. Currently, the only effective treatment for PE is timely termination of pregnancy, which comes with increased perinatal risks. However, there is no effective way to delay pathological progress and improve maternal and fetal outcomes. In light of this, it is of great significance to seek effective therapeutic strategies for PE. Exosomes which are nanoparticles carrying bioactive substances such as proteins, lipids, and nucleic acids, have emerged as a novel vehicle for intercellular communication. Mesenchymal stem cell-derived exosomes (MSC-Exos) participate in various important physiological processes, including immune regulation, cell proliferation and migration, and angiogenesis, and have shown promising potential in tissue repair and disease treatment. Recently, MSC-Exos therapy has gained popularity in the treatment of ischaemic diseases, immune dysfunction, inflammatory diseases, and other fields due to their minimal immunogenicity, characteristics similar to donor cells, ease of storage, and low risk of tumor formation. This review elaborates on the potential therapeutic mechanism of MSC-Exos in treating preeclampsia, considering the main pathogenic factors of the condition, including placental vascular dysplasia, immunological disorders, and oxidative stress, based on the biological function of MSC-Exos. Additionally, we discuss in depth the advantages and challenges of MSC-Exos as a novel acellular therapeutic agent in preeclampsia treatment.

Role of Soluble Urokinase-Type Plasminogen Activator Receptor in Cardiovascular Disease

PURPOSE OF REVIEW

Chronic inflammation is a major contributor to cardiovascular disease (CVD) risk. Soluble urokinase plasminogen activator receptor (suPAR) is an immune-derived glycoprotein that is strongly associated with atherosclerotic disease. This review summarizes evidence on suPAR's role in CVD pathogenesis and its potential as a prognostic indicator and therapeutic target.

RECENT FINDINGS

Clinical, genetic, and experimental evidence supports suPAR's role as a pathogenic factor in atherosclerosis. suPAR promotes atherosclerosis through modulation of monocyte activation and function. Clinically, elevated suPAR levels are linked to increased cardiovascular risk across diverse populations. Ongoing clinical trials are evaluating therapies targeting suPAR signaling. Current evidence positions suPAR as a regulator of myeloid cell function that contributes to vascular inflammation and subsequent cardiovascular events. Additional research is needed to determine whether suPAR measurement can improve CVD risk prediction and enable personalized management. Overall, suPAR is a promising immune-derived biomarker and target for reducing inflammation and cardiovascular risk.

New insights of miRNA molecular mechanisms in breast cancer brain metastasis and therapeutic targets

Brain metastases in breast cancer (BC) patients are often associated with a poor prognosis. Recent studies have uncovered the critical roles of miRNAs in the initiation and progression of BC brain metastasis, highlighting the disease's underlying molecular pathways. miRNA-181c, miRNA-10b, and miRNA-21, for example, are all overexpressed in BC patients. It has been shown that these three miRNAs help tumors grow and metastasize by targeting genes that control how cells work. On the other hand, miRNA-26b5p, miRNA-7, and miRNA-1013p are all downregulated in BC brain metastasis patients. They act as tumor suppressors by controlling the expression of genes related to cell adhesion, angiogenesis, and invasion. Therapeutic miRNA targeting has considerable promise in treating BC brain metastases. Several strategies have been proposed to modulate miRNA expression, including miRNA-Mimics, antagomirs, and small molecule inhibitors of miRNA biogenesis. This review discusses the aberrant expression of miRNAs and metastatic pathways that lead to the spread of BC cells to the brain. It also explores miRNA therapeutic target molecular mechanisms and BC brain metastasis challenges with advanced strategies. The targeting of certain miRNAs opens a new door for the development of novel therapeutic approaches for this devastating disease.

Role of soluble urokinase type plasminogen activator receptor (suPAR) in predicting mortality, readmission, length of stay and discharge in emergency patients: A systematic review and meta analysis

BACKGROUND

Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory biomarker that is used to predict mortality, readmission, early discharge, and LOS, thus, serves as a useful tool for ED physicians. Our study aims to analyze the efficacy of suPAR in predicting these prognostic markers in ED.

METHODS

We performed a comprehensive search on 6 databases from the inception to 30th November 2022, to select the following eligibility criteria; a) observation or triage trial studies investigating the role of suPAR levels in predicting: 30 day and 90-day mortality, 30-day readmission, early discharge (within 24hr), and LOS in patients coming to AMU.

RESULTS

A total of 13 studies were included, with a population size of 35,178, of which 52.9% were female with a mean age of 62.93 years. Increased risk of 30-day mortality (RR = 10.52; 95% CI = 4.82-22.95; I2 = 38%; P < .00001), and risk of 90-day mortality (RR = 5.76; 95% CI = 3.35-9.91; I2 = 36%; P < .00001) was observed in high suPAR patients. However, a slightly increased risk was observed for 30-day readmission (RR = 1.50; 95% CI = 1.16-1.94; I2 = 54%; P = .002). More people were discharged within 24hr in the low suPAR level group compared to high suPAR group (RR = 0.46; 95% CI = 0.40-0.53; I2 = 41%; P < .00001). LOS was thrice as long in high suPAR level patients than in patients with low suPAR (WMD = 3.20; 95% CI = 1.84-4.56; I2 = 99%; P < .00001).

CONCLUSION

suPAR is proven to be a significant marker in predicting 30-day and 90-day mortality in ED patients.

SuPAR in major depression: Association with 26 weeks antidepressant response and 10-year depression outcomes

Introduction

Inflammation has been associated with depression and differential antidepressant (AD) treatment response. Soluble urokinase plasminogen activator receptor (suPAR) is a novel measure of chronic inflammation. We investigated whether suPAR is associated with depression severity and AD response.

Methods

We included 90 patients with major depressive disorder (MDD) who participated in a part-randomized clinical trial of 26 weeks of treatment with escitalopram or nortriptyline. suPAR levels were measured in serum samples collected at baseline and after 8, 12 and 26 weeks. Mixed effects models for the association between suPAR levels and AD response were performed. By merging with Danish nationwide registers, we included information on psychiatric hospital contacts during ten years after the GENDEP trial. Cox regression analyses calculated the hazard rate ratios between suPAR levels and subsequent hospitalizations.

Results

At baseline, higher suPAR levels were not associated with overall depression severity but with greater severity of neurovegetative depressive symptoms, specifically appetite and weight changes. 57 (63.3%) patients responded positively to treatment. Among 57 (63.3%) patients who achieved response, those who responded had significantly higher baseline suPAR levels levels, and response was associated with a significant decrease in suPAR during AD treatment. Remitters decreased from 3.1 ng/ml at baseline to 2.8 ng/ml after 26 weeks (p = 0.003) and responders from 3.0 to 2.8 ng/ml (p = 0.02), whereas non-remitters and non-responders showed unchanged suPAR levels. We found no correlation between a change in suPAR and a change in MADRS, but a lowering of suPAR correlated with a decrease in neurovegetative symptoms. We found no association between suPAR levels and 10-year risk for hospitalizations.

Discussion

The present study suggests that an elevated level of chronic inflammation, measured as the suPAR level, is associated with better response to AD treatment.

Associations between plasma inflammatory markers and psychotic disorder, depressive disorder and generalised anxiety disorder in early adulthood: A nested case-control study

BACKGROUND

Low-grade inflammation may occur in association with several mental disorders of early adulthood, though associations with markers of chronic inflammation such as soluble urokinase plasminogen activator receptor (suPAR) are less well-established. We aimed to examine associations between acute and chronic inflammatory markers and mental disorders, as well as psychiatric co-morbidity, in young adults aged 24 years in the Avon Longitudinal Study of Parents and Children.

METHODS

Included were 781 participants (of 4019 who attended at age 24 years) who completed psychiatric assessments and provided plasma samples. Of these, 377 met criteria for psychotic disorder, depressive disorder or generalised anxiety disorder and 404 did not. Plasma concentrations of IFN-γ, IL-6, IL-8, IL-10, TNF-α, CRP, sVCAM1, sICAM1, suPAR and alpha-2-macroglobulin were measured using immunoassays. Logistic regression compared standardised inflammatory marker levels in cases and controls. Negative binomial regression evaluated associations between inflammatory markers and co-morbidity (number of mental disorders). Models were adjusted for sex, body mass index, cigarette smoking, cannabis use and employment status, then additionally for childhood trauma.

RESULTS

For psychotic disorder, there was evidence for associations with IL-6 (odds ratio[OR] 1.68, 95 %CI 1.20-2.34) and suPAR (OR 1.74, 95 %CI 1.17-2.58). There was weaker evidence for an association between suPAR and depressive disorder (OR 1.31, 95 %CI 1.05-1.62). There was little evidence for associations between inflammatory markers and generalised anxiety disorder. There was weak evidence for an association between suPAR and co-morbidity (β 0.10, 95 %CI 0.01-0.19). There was little evidence for additional confounding by childhood trauma.

CONCLUSIONS

There was evidence that 24-year-olds with psychotic disorder had raised plasma IL-6 and suPAR concentrations compared to controls. These findings have implications regarding the role of inflammation in mental disorders in early adulthood.

Soluble Urokinase-Type Plasminogen Activator Receptor as a Prognostic Marker of Ugandan Children at Risk of Severe and Fatal Malaria

BACKGROUND

Current malaria diagnostic tests do not reliably identify children at risk of severe and fatal infection. Host immune and endothelial activation contribute to malaria pathogenesis. Soluble urokinase-type plasminogen activator receptor (suPAR) is a marker of these pathways. We hypothesized that measuring suPAR at presentation could risk-stratify children with malaria.

METHODS

Plasma suPAR levels were determined in consecutive febrile children with malaria at presentation to hospital in Jinja, Uganda. We evaluated the accuracy of suPAR in predicting in-hospital mortality, and whether suPAR could improve a validated clinical scoring system (Lambaréné Organ Dysfunction Score [LODS]).

RESULTS

Of the 1226 children with malaria, 39 (3.2%) died. suPAR concentrations at presentation were significantly higher in children who went on to die than in those who survived (P < .0001). suPAR levels were associated with disease severity (LODS: 0 vs 1, P = .001; 1 vs 2, P < .001; 2 vs 3, 0 vs 2, 1 vs 3, and 0 vs 3, P < .0001). suPAR concentrations were excellent predictors of in-hospital mortality (area under the receiver operating characteristic curve [AUROC], 0.92 [95% confidence interval {CI}, .91-.94]). The prognostic accuracy of LODS (AUROC, 0.93 [95% CI, .91-.94]) was improved when suPAR was added (AUROC, 0.97 [95% CI, .96-.98]; P < .0001).

CONCLUSIONS

Measuring suPAR at presentation can identify children at risk of severe and fatal malaria. Adding suPAR to clinical scores could improve the recognition and triage of children at risk of death. suPAR can be detected with a point-of-care test and can now be evaluated in prospective trials.

Concentrations of urinary neopterin, but not suPAR, positively correlate with age in rhesus macaques

Identifying biomarkers of age-related changes in immune system functioning that can be measured non-invasively is a significant step in progressing research on immunosenescence and inflammaging in free-ranging and wild animal populations. In the present study, we aimed to investigate the suitability of two urinary compounds, neopterin and suPAR, as biomarkers of age-related changes in immune activation and inflammation in a free-ranging rhesus macaque (Macaca mulatta) population. We also investigated age-associated variation in gene transcription from blood samples to understand the underlying proximate mechanisms that drive age-related changes in urinary neopterin or suPAR. Neopterin was significantly positively correlated with age, and had a moderate within-individual repeatability, indicating it is applicable as a biomarker of age-related changes. The age-related changes in urinary neopterin are not apparently driven by an age-related increase in the primary signaler of neopterin, IFN-y, but may be driven instead by an age-related increase in both CD14+ and CD14− monocytes. suPAR was not correlated with age, and had low repeatability within-individuals, indicating that it is likely better suited to measure acute inflammation rather than chronic age-related increases in inflammation (i.e., “inflammaging”). Neopterin and suPAR had a correlation of 25%, indicating that they likely often signal different processes, which if disentangled could provide a nuanced picture of immune-system function and inflammation when measured in tandem.

suPAR to Risk-Stratify Patients With Malaria

Severe malaria (SM) is a leading cause of global morbidity and mortality, particularly in children in sub-Saharan Africa. However, existing malaria diagnostic tests do not reliably identify children at risk of severe and fatal outcomes. Dysregulated host immune and endothelial activation contributes to the pathogenesis of SM. Current research suggests that measuring markers of these pathways at presentation may have clinical utility as prognostic indicators of disease progression and risk of death. In this review, we focus on the available evidence implicating soluble urokinase-type plasminogen activator receptor (suPAR) as a novel and early predictor of severe and fatal malaria and discuss its potential utility for malaria triage and management.

Soluble Urokinase Plasminogen Activator Receptor (suPAR) in the Emergency Department (Ed): A Tool for the Assessment of Elderly Patients

Emergency department (ED) overcrowding is a global issue setting challenges to all care providers. Elderly patients are frequent visitors of the ED and their risk stratification is demanding due to insufficient assessment methods. A prospective cohort study was conducted to determine the risk-predicting value of a prognostic biomarker, soluble urokinase plasminogen activator receptor (suPAR), in the ED, concentrating on elderly patients. SuPAR levels were determined as part of standard blood sampling of 1858 ED patients. The outcomes were assessed in the group of <75 years (=younger) and ≥75 years (=elderly). The elderly had higher median suPAR levels than the younger (5.4 ng/mL vs. 3.7 ng/mL, p < 0.001). Increasing suPAR levels were associated with higher probability for 30-day mortality and hospital admission in all age groups. SuPAR also predicted 30-day mortality when adjusted to other clinical factors. SuPAR acts successfully as a nonspecific risk predictor for 30-day mortality, independently and with other risk-assessment tools. Low suPAR levels predict positive outcomes and could be used in the discharging process. A cut-off value of 4 ng/mL could be used for all ED patients, 5 ng/mL being a potential alternative in elderly patients.

Relationship Between Soluble Urokinase Plasminogen Activator Receptor (suPAR) and Disease Outcome in Adult-Onset Asthma

Background

Objective

Methods

Results

Conclusion

Longitudinal associations between adolescents' individualised risk for depression and inflammation in a UK cohort study

Inflammation is associated with poor physical and mental health including major depressive disorder (MDD). Moreover, there is evidence that childhood adversity - a risk factor for MDD - becomes biologically embedded via elevated inflammation. However, the risk of developing MDD arises from multiple sources and yet there has been little investigation of the links between individuals' constellation of MDD risk and subsequent inflammation. We therefore examined associations between individual risk for MDD calculated in early adolescence and levels of inflammation six years later. We use data from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative UK birth cohort of 2,232 children followed to age 18 with 93% retention. Participants' individual risk for developing future MDD was calculated at age 12 using a recently developed prediction model comprising multiple psychosocial factors. Plasma levels of three inflammation biomarkers were measured at age 18: C-reactive protein (CRP), interleukin-6 (IL-6), and a newer biomarker, soluble urokinase plasminogen activator receptor (suPAR), which is thought to reflect the level of systemic chronic inflammation. MDD risk scores calculated at age 12 were positively associated with levels of suPAR (but not CRP or IL-6) at age 18 after adjusting for key covariates (b = 1.70, 95% CI = 0.46 - 2.95, p = 0.007). Adolescents at high risk of MDD (risk scores ≥ 90th centile) had significantly higher mean levels of suPAR six years later than adolescents who had been identified as low risk (risk scores ≤ 10th centile) (b = 0.41, 95% CI = 0.18 - 0.64, p < 0.001). Findings support the notion that childhood psychosocial risk for MDD leads to increased levels of low-grade inflammation. If replicated in studies with repeated assessments of inflammation biomarkers throughout childhood and adolescence, these findings would support targeted interventions to reduce inflammation, as measured by suPAR, for adolescents at high risk of MDD to potentially prevent development of depression and physical health problems related to chronic inflammation.

Chronic inflammation markers and cytokine-specific autoantibodies in Danish blood donors with restless legs syndrome

Restless Legs Syndrome (RLS) is a neurological sensorimotor disorder negatively impacting sufferers’ quality of sleep and health-related quality of life. The pathophysiology of RLS is poorly understood and research focusing on the link between RLS and inflammation has been limited. Our study aimed to investigate whether chronic inflammation markers C-reactive protein (CRP) and soluble urokinase-type plasminogen activator receptor (suPAR), as well plasma levels of five different cytokine-specific autoantibodies (c-aAb), i.e. modulators of inflammation, associate with RLS in otherwise healthy individuals. CRP, suPAR and c-aAb were measured in plasma samples of participants from the Danish Blood Donor Study in 2010. Returning donors between 2015 and 2018 completed the validated Cambridge-Hopkins RLS-questionnaire for RLS assessment, resulting in datasets with RLS assessment and values for CRP (N = 3564), suPAR (N = 2546) and c-aAb (N = 1478). We performed logistic regression models using the CRP, suPAR or c-aAb as the independent variable and RLS status as the dependent variable, adjusted for appropriate covariates. Our study indicates that a high concentration of CRP is associated with RLS, while an increased probability of experiencing frequent RLS symptoms in those with an elevated plasma suPAR level appears to be mediated through lifestyle factors. We additionally report that a high titer of autoantibodies specific against the cytokine interferon-alpha was associated with RLS. Our results support the existence of links between systemic inflammation and RLS, though further RLS studies on CRP, suPAR and c-aAb in larger cohorts are warranted to confirm our findings and further reveal the hitherto underexplored links between RLS and inflammation.

Soluble Urokinase Plasminogen Activator Receptor (suPAR) as a Biomarker of Systemic Chronic Inflammation

Systemic chronic inflammation (SCI) is persistent, health-damaging, low-grade inflammation that plays a major role in immunosenescence and in development and progression of many diseases. But currently, there are no recognized standard biomarkers to assess SCI levels alone, and SCI is typically measured by combining biomarkers of acute inflammation and infection, e.g., CRP, IL-6, and TNFα. In this review, we highlight 10 properties and characteristics that are shared by the blood protein soluble urokinase plasminogen activator receptor (suPAR) and SCI, supporting the argument that suPAR is a biomarker of SCI: (1) Expression and release of suPAR is upregulated by immune activation; (2) uPAR and suPAR exert pro-inflammatory functions; (3) suPAR is associated with the amount of circulating immune cells; (4) Blood suPAR levels correlate with the levels of established inflammatory biomarkers; (5) suPAR is minimally affected by acute changes and short-term influences, in contrast to many currently used markers of systemic inflammation; (6) Like SCI, suPAR is non-specifically associated with multiple diseases; (7) suPAR and SCI both predict morbidity and mortality; (8) suPAR and SCI share the same risk factors; (9) suPAR is associated with risk factors and outcomes of inflammation above and beyond other inflammatory biomarkers; (10) The suPAR level can be reduced by anti-inflammatory interventions and treatment of disease. Assessing SCI has the potential to inform risk for morbidity and mortality. Blood suPAR is a newer biomarker which may, in fact, be a biomarker of SCI since it is stably associated with inflammation and immune activation; shares the same risk factors as many age-related diseases; is both elevated by and predicts age-related diseases. There is strong evidence that suPAR is a prognostic marker of adverse events, morbidity, and mortality. It is associated with immune activity and prognosis across diverse conditions, including kidney disease, cardiovascular disease, cancer, diabetes, and inflammatory disorders. Thus, we think it likely represents a common underlying disease-process shared by many diseases; that is, SCI. We review the supporting literature and propose a research agenda that can help test the hypothesis that suPAR indexes SCI, with the potential of becoming the new gold standard for measuring SCI.

Elevated preoperative suPAR is a strong and independent risk marker for postoperative complications in patients undergoing major noncardiac surgery (SPARSE)

BACKGROUND

Patients undergoing major surgery are often at risk of developing postoperative complications. We investigated whether a preoperative marker of chronic inflammation, soluble urokinase plasminogen activator receptor, can aid in identifying patients at high risk for postoperative complications, morbidity, and mortality.

METHODS

In this prospective observational study (ClinicalTrials.gov identifier: NCT03851965), EDTA blood was collected from consecutive adult White patients scheduled for major noncardiac surgery with expected duration ≥2 hours under general anesthesia. Inclusion criteria were age ≥18 years and American Society of Anesthesiologists physical status I to IV. Plasma soluble urokinase plasminogen activator receptor levels were determined using the suPARnostic quick triage lateral flow assay. The primary endpoint was postoperative complications defined as presence of any complication and/or admission to intensive care unit and/or mortality within the first 90 postoperative days.

RESULTS

Preoperative soluble urokinase plasminogen activator receptor had an odds ratio of 1.50 (95% confidence interval: 1.24-1.82) for every ng/mL increase. When including age, sex, American Society of Anesthesiologists score, C-reactive protein, and grouped soluble urokinase plasminogen activator receptor in multivariate analysis, patients with soluble urokinase plasminogen activator receptor between 5.5 and 10 ng/mL had an odds ratio of 11.2 (confidence interval: 3.1-40.8) and patients with soluble urokinase plasminogen activator receptor >10 ng/mL had an odds ratio of 19.9 (95% confidence interval: 4.3-92.9) compared to patients with soluble urokinase plasminogen activator receptor ≤5.5 ng/mL, respectively. Receiver operating characteristic analysis of soluble urokinase plasminogen activator receptor showed an area under the curve of 0.82 (confidence interval: 0.72-0.91). Receiver operating characteristic analysis combining age, sex, C-reactive protein levels, and American Society of Anesthesiologists score and had an area under the curve of 0.71 (95% confidence interval: 0.61-0.82). Adding soluble urokinase plasminogen activator receptor to this model increased the area under the curve to 0.83 (95% confidence interval: 0.74-0.92) (P = .033).

CONCLUSION

Preoperative soluble urokinase plasminogen activator receptor provided strong and independent predictive value on postoperative complications in White patients undergoing major noncardiac surgery.

Exploring low grade inflammation by soluble urokinase plasminogen activator receptor levels in schizophrenia: a sex-dependent association with depressive symptoms

BACKGROUND

There is evidence of increased low grade inflammation (LGI) in schizophrenia patients. However, the inter-individual variation is large and the association with demographic, somatic and psychiatric factors remains unclear. Our aim was to explore whether levels of the novel LGI marker soluble urokinase plasminogen activator receptor (suPAR) were associated with clinical factors in schizophrenia and if such associations were sex-dependent.

METHOD

In this observational study a total of 187 participants with schizophrenia (108 males, 79 females) underwent physical examination and assessment with clinical interviews (Positive and Negative Syndrome Scale (PANSS), Calgary Depression Scale for Schizophrenia (CDSS), Alcohol Use Disorder Identification Test (AUDIT), and Drug Use Disorder Identification Test (DUDIT)). Blood levels of suPAR, glucose, lipids, and high sensitivity C-reactive protein (hsCRP) were determined and body mass index (BMI) calculated. Multivariable linear regression analyses were used adjusting for confounders, and sex interaction tested in significant variables.

RESULTS

Adjusting for sex, age, current tobacco smoking and BMI, we found that levels of hsCRP and depressive symptoms (CDSS) were positively associated with levels of suPAR (p < 0.001). The association between suPAR and CDSS score was significant in females (p < 0.001) but not in males. Immune activation measured by hsCRP was not associated with depressive symptoms after adjusting for BMI.

CONCLUSION

Our findings indicate that increased suPAR levels are associated with depressive symptoms in females with schizophrenia, suggesting aberrant immune activation in this subgroup. Our results warrant further studies, including longitudinal follow-up of suPAR levels in schizophrenia and experimental studies of mechanisms.

Soluble urokinase plasminogen activator receptor (suPAR) predicts critical illness and kidney failure in patients admitted to the intensive care unit

Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory biomarker and risk factor for kidney diseases, with a potential prognostic value in critically ill patients. In this monocentric prospective study, we measured plasma suPAR levels immediately after ICU admission in unselected 237 consecutive patients using a turbidimetric assay. Primary objective was the prognostic value for ICU- and 28-day mortality. Secondary objectives were association with sequential organ failure assessment (SOFA) score, coagulation and inflammation markers, AKI-3 and differences in prespecified subgroups. Median suPAR levels were 8.0 ng/mL [25th-75th percentile 4.3-14.4], with lower levels in ICU survivors than non-survivors (6.7 vs. 11.6 ng/mL, p < 0.001). SuPAR levels were higher in COVID-19, kidney disease, moderate-to-severe liver disease, and sepsis. ICU mortality increased by an odds ratio (OR) of 4.7 in patients with the highest compared to lowest quartile suPAR. Kaplan-Meier overall survival estimates at 3 months were 63% and 49%, in patients with suPAR below/above 12 ng/mL (log-rank p = 0.027). Due to an observed interaction between SOFA score and suPAR, we performed a random forest method identifying cutoffs. ICU mortality was 53%, 17% and 2% in patients with a SOFA score > 7, SOFA ≤ 7 & suPAR > 8 ng/mL, and SOFA score ≤ 7 & suPAR ≤ 8 ng/mL, respectively. suPAR was a significant predictor for AKI-3 occurrence (OR per doubling 1.89, 95% CI: 1.20-2.98; p = 0.006). suPAR levels at ICU admission may offer additional value for risk stratification especially in ICU patients with moderate organ dysfunction as reflected by a SOFA score ≤ 7.

A Low-Sodium DASH Dietary Pattern Affects Serum Markers of Inflammation and Mineral Metabolism in Adults with Elevated Blood Pressure

BACKGROUND

The blood pressure-lowering effects of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and reduced sodium intake are well established. The effects on other biomarkers related to vascular health are of interest and might assist in explaining the effects of the DASH diet and sodium reduction.

OBJECTIVES

We hypothesized that a low-sodium DASH diet improves (lowers) biomarkers of inflammation [C-reactive protein (CRP) and soluble urokinase plasminogen activator receptor (suPAR)] and mineral metabolism [phosphorus and fibroblast growth factor-23 (FGF23)].

METHODS

We conducted a secondary analysis of the DASH-Sodium trial using frozen serum samples. This controlled feeding study randomly assigned 412 adults (≥22 y) with elevated blood pressure (120-159/80-95 mmHg) to consume either a DASH diet or control diet. Within each arm, participants received 3 sodium levels [low (1150 mg), intermediate (2300 mg), high (3450 mg)] in random sequence, each for 30 d. To maximize contrast, samples collected at the end of the low-sodium DASH (n = 198) and high-sodium control (n = 194) diets were compared. Between-diet differences in serum CRP, suPAR, phosphorus, and FGF23 concentrations were assessed using linear regression adjusted for age, sex, race, income, education, smoking status, and BMI.

RESULTS

CRP concentrations did not differ between groups (P = 0.83), but suPAR was higher after the low-sodium DASH diet than the high-sodium control [geometric mean 2470 pg/mL (95% CI: 2380, 2560 pg/mL), compared with 2290 pg/mL (95% CI: 2210, 2380 pg/mL); P = 0.006]. Phosphorus was higher after the low-sodium DASH diet [geometric mean 3.50 mg/dL (95% CI: 3.43, 3.57 mg/dL)] compared with the high-sodium control diet [geometric mean 3.39 mg/dL (95% CI: 3.33, 3.46 mg/dL); P = 0.04]. FGF23 was also higher after the low-sodium DASH diet [geometric mean 35.3 pg/mL (95% CI: 33.3, 37.3 pg/mL) compared with 28.2 pg/mL (95% CI: 26.6, 29.8 pg/mL); P < 0.001].

CONCLUSIONS

Contrary to our hypothesis, biomarkers of inflammation and mineral metabolism were increased or unchanged by a low-sodium DASH diet compared with a high-sodium control diet in adults with elevated blood pressure.

Association Between Elevated suPAR, a New Biomarker of Inflammation, and Accelerated Aging

Background

To understand and measure the association between chronic inflammation, aging, and age-related diseases, broadly applicable standard biomarkers of systemic chronic inflammation are needed. We tested whether elevated blood levels of the emerging chronic inflammation marker soluble urokinase plasminogen activator receptor (suPAR) were associated with accelerated aging, lower functional capacity, and cognitive decline.

Methods

We used data from the Dunedin Study, a population-representative 1972–1973 New Zealand birth cohort (n = 1037) that has observed participants to age 45 years. Plasma suPAR levels were analyzed at ages 38 and 45 years. We performed regression analyses adjusted for sex, smoking, C-reactive protein, and current health conditions.

Results

Of 997 still-living participants, 875 (88%) had plasma suPAR measured at age 45. Elevated suPAR was associated with accelerated pace of biological aging across multiple organ systems, older facial appearance, and with structural signs of older brain age. Moreover, participants with higher suPAR levels had greater decline in physical function and cognitive function from childhood to adulthood compared to those with lower suPAR levels. Finally, improvements in health habits between ages 38 and 45 (smoking cessation or increased physical activity) were associated with less steep increases in suPAR levels over those years.

Conclusions

Our findings provide initial support for the utility of suPAR in studying the role of chronic inflammation in accelerated aging and functional decline.

Influenza vaccination in the elderly boosts antibodies against conserved viral proteins and egg-produced glycans

Seasonal influenza vaccination elicits a diminished adaptive immune response in the elderly, and the mechanisms of immunosenescence are not fully understood. Using Ig-Seq, we found a marked increase with age in the prevalence of cross-reactive (CR) serum antibodies that recognize both the H1N1 (vaccine-H1) and H3N2 (vaccine-H3) components of an egg-produced split influenza vaccine. CR antibodies accounted for 73% ± 18% of the serum vaccine responses in a cohort of elderly donors, 65% ± 15% in late middle-aged donors, and only 13% ± 5% in persons under 35 years of age. The antibody response to non-HA antigens was boosted by vaccination. Recombinant expression of 19 vaccine-H1+H3 CR serum monoclonal antibodies (s-mAbs) revealed that they predominantly bound to non-HA influenza proteins. A sizable fraction of vaccine-H1+H3 CR s-mAbs recognized with high affinity the sulfated glycans, in particular sulfated type 2 N-acetyllactosamine (Galβ1-4GalNAcβ), which is found on egg-produced proteins and thus unlikely to contribute to protection against influenza infection in humans. Antibodies against sulfated glycans in egg-produced vaccine had been identified in animals but were not previously characterized in humans. Collectively, our results provide a quantitative basis for how repeated exposure to split influenza vaccine correlates with unintended focusing of serum antibody responses to non-HA antigens that may result in suboptimal immunity against influenza.

Eleven genomic loci affect plasma levels of chronic inflammation marker soluble urokinase-type plasminogen activator receptor

Soluble urokinase-type plasminogen activator receptor (suPAR) is a chronic inflammation marker associated with the development of a range of diseases, including cancer and cardiovascular disease. The genetics of suPAR remain unexplored but may shed light on the biology of the marker and its connection to outcomes. We report a heritability estimate of 60% for the variation in suPAR and performed a genome-wide association meta-analysis on suPAR levels measured in Iceland (N = 35,559) and in Denmark (N = 12,177). We identified 13 independently genome-wide significant sequence variants associated with suPAR across 11 distinct loci. Associated variants were found in and around genes encoding uPAR (PLAUR), its ligand uPA (PLAU), the kidney-disease-associated gene PLA2R1 as well as genes with relations to glycosylation, glycoprotein biosynthesis, and the immune response. These findings provide new insight into the causes of variation in suPAR plasma levels, which may clarify suPAR's potential role in associated diseases, as well as the underlying mechanisms that give suPAR its prognostic value as a unique marker of chronic inflammation.

Plasma levels of soluble urokinase plasminogen activator receptor (suPAR) and high-sensitivity C-reactive protein after Roux-en-Y gastric bypass or sleeve gastrectomy: a 1-year prospective observational study

PURPOSE

Low-grade inflammation in obesity contributes to the development of cardiovascular disease, diabetes mellitus and cancer, and is associated with increased mortality. The purpose of this 1-year prospective observational study was to examine the weight loss effect of bariatric surgery on plasma concentrations of two inflammatory markers, namely high-sensitivity C-reactive protein (hsCRP) and soluble urokinase-type plasminogen activator receptor (suPAR), in patients with obesity.

METHODS

Sixteen subjects without obesity and 32 patients with obesity class III, who had already settled upon Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) were included in the study. Subjects without obesity were examined once, at baseline; patients with obesity were examined preoperatively (baseline) and 3, 6 and 12 months postoperatively.

RESULTS

Plasma suPAR and hsCRP concentrations at baseline were higher in patients with obesity than in lean participants (2.68 ± 0.86 vs 1.86 ± 0.34 ng/mL, p < 0.001 and 9.83 ± 9.55 vs 1.36 ± 1.95 mg/dL, p < 0.001). Levels of suPAR following bariatric surgery increased significantly 3 months after either RYGB or SG (3.58 ± 1.58 vs 3.26 ± 0.7 ng/mL, respectively) and declined at 6 (3.19 ± 1.75 vs 2.8 ± 0.84 ng/mL, respectively) and 12 months (2.6 ± 1.5 vs 2.22 ± 0.49 ng/mL, respectively; p < 0.05 for the effect of time on suPAR levels during the study), whereas those of hsCRP declined consistently after bariatric surgery (3 months: 5.44 ± 3.99 vs 9.47 ± 11.98 mg/dL, respectively; 6 months; 5.39 ± 5.6 vs 10.25 ± 17.22 mg/dL, respectively; and 12 months: 2.23 ± 2.5 vs 3.07 ± 3.63 mg/dL, respectively; p < 0.001 for the effect of time on hsCRP levels during the study). 1-year change in BMI was negatively associated with suPAR levels at 12 months.

CONCLUSION

Our findings support an association between obesity and low-grade inflammation. Weight loss following bariatric surgery is associated with a consistent decline in plasma hsCRP, while plasma suPAR levels increase at 3 months and decline by 12 months.

Index of Body Inflammation for Maxillofacial Surgery Purpose-to Make the Soluble Urokinase-Type Plasminogen Activator Receptor Serum Level Independent on Patient Age

Background: The serum suPAR level is affected in humans by it increases with age. Therefore it makes difficult interpretation and any comparison of age varied groups. The aim of this study is to find simple way to age independent presentation of suPAR serum level for maxillofacial surgery purpose. Methods: In generally healthy patients from 15 to 59 y.o. suPAR level was tested in serum before orthognathic or minor traumatologic procedures. Five ways to make the suPAR serum level assessment independent of age are proposed. Results: One way of making suPAR levels independent of age led to the result with the same statistical distribution as in the raw suPAR serum material and this distribution is the normal. Conclusion: The simple way for suPAR serum level analysis without its dependence on patient age is calculation of the index of body inflammation understood as square root of squared suPAR serum level divided by logarithm of patient age to base 10.

Soluble urokinase plasminogen activator receptor level in individuals of advanced age

Soluble urokinase plasminogen activator receptor (suPAR) is a biomarker whose clinical value has been tested in various groups of patients. The aim of the present study was to determine the suPAR level in a previously uninvestigated population of 182, generally healthy, community-dwelling seniors aged 74–89 years. In addition to suPAR level, selected laboratory parameters of heart and kidney function, lipid and C-reactive protein levels were determined. A group of 45 younger individuals aged 24–66 years was used for comparison. The seniors had higher suPAR levels than younger controls: 3.79 ng/mL (95% CI 3.64–3.96 ng/mL) vs. 3.16 ng/mL (95% CI 2.86–3.45 ng/mL). These levels increased further with advancing age, and were similar in women and men. A multiple regression model confirmed that biomarker level was related to cardiac function, renal function and inflammation, and this remained after adjusting for age. These correlation patterns were similar in older women and men.

The effect of circadian-adjusted LED-based lighting on sleep, daytime sleepiness and biomarkers of inflammation in a randomized controlled cross-over trial by pragmatic design in elderly care home dwellers

AIM

Elderly multimorbid care home dwellers are a heterogenic group of frail individuals that exhibit sleep disturbances and a range of co-morbidities. The project aimed to study the possible effect of indoor circadian-adjusted LED-lighting (CaLED) in the elderly residents' care home on their sleeping patterns and systemic biomarkers associated with inflammation.

METHODS

A 16-week trial study was performed to follow the intervention and control groups using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) to monitor sleep and daytime sleepiness, and biomarkers IL-6, TNF-α and suPAR, to estimate the levels of inflammation.

RESULTS

There was no significant impact on sleep improvement after the short intervention time when analyzing the PSQI and ESS results. However, we found several challenges using these tools for this specific group of individuals. Thus, important knowledge was gained for future studies in elderly care home dwellers. The inflammation state throughout the entire study period was stable for most of the elderly and no significant change was detected from before to after the intervention. This study represents a first-to-date attempt to ameliorate the adverse effects of sleep disturbances that characterize a randomly chosen group of elderly multimorbid subjects, by using circadian-adjusted LED-lighting in a natural care home environment.

CONCLUSION

In this pragmatic randomized study of home dwelling individuals we were not able to demonstrate an improved sleep pattern as judged by PSQI, ESS or a change in inflammatory state.

Elevated suPAR Is an Independent Risk Marker for Incident Kidney Disease in Acute Medical Patients

Introduction

Identifying patients at high risk of developing kidney disease could lead to early clinical interventions that prevent or slow disease progression. Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory biomarker thought to be involved in the pathogenesis and development of kidney disease. We aimed to determine whether elevated plasma suPAR measured at hospital admission is associated with incident kidney disease in patients presenting to the emergency department.

Materials and Methods

This was a retrospective registry-based cohort study performed at the Emergency Department of Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark. Patients were included in the study from November 2013 to March 2017 and followed until June 2017. Patients were excluded if they were diagnosed with kidney disease or died prior to index discharge. Plasma suPAR was measured at hospital admission, and the main outcome was time to incident kidney disease, defined by ICD-10 diagnosis codes for both chronic and acute kidney conditions. Association between suPAR and time to incident kidney disease was assessed by Cox proportional hazard regression analysis.

Results

In total, 25,497 patients (median age 58.1 years; 52.5% female) were admitted to the emergency department and followed for development of kidney disease. In multivariable Cox regression analysis adjusting for age, sex, eGFR, CRP, cardiovascular disease, hypertension, and diabetes, each doubling in suPAR at hospital admission was associated with a hazard ratio of 1.57 (95% CI: 1.38–1.78, P < 0.001) for developing a chronic kidney condition and 2.51 (95% CI: 2.09–3.01, P < 0.001) for developing an acute kidney condition.

Discussion

In a large cohort of acutely hospitalized medical patients, elevated suPAR was independently associated with incident chronic and acute kidney conditions. This highlights the potential for using suPAR in risk classification models to identify high-risk patients who could benefit from early clinical interventions. The main limitation of this study is its reliance on accurate reporting of ICD-10 codes for kidney disease.

Soluble urokinase plasminogen activator receptor (suPAR) is lower in disease-free patients but cannot rule out incident disease in patients with suspected cancer

BACKGROUND

Accurate first-line diagnostics are essential for early recognition of cancer but also to identify patients free of disease. The biomarker soluble urokinase plasminogen activator receptor (suPAR) is elevated in patients with cancer or non-malignant disease compared to disease-free patients. We tested if low suPAR could be used to identify disease-free patients in an accelerated cancer diagnostics program, including ruling out cancer.

METHODS

Patients with serious nonspecific symptoms and signs of cancer (NSSC) were included at the Diagnostic Outpatient Clinic, Copenhagen University Hospital Hvidovre, Denmark. Data from a clinical examination, including blood tests and imaging, was combined with national registry data on diagnoses and mortality. The association between blood suPAR and the primary outcome of disease-free (i.e., absence of incident disease and mortality) within 1-year follow-up was analysed with logistic regression analysis.

RESULTS

Of 1583 patients included, 349 (22.0%) were diagnosed with cancer, 837 (52.9%) with non-malignant disease, and 392 (25.8%) were disease-free within one year. Admission suPAR was significantly lower in disease-free patients compared to patients with cancer or non-malignant disease (P < 0.001), area under the curve 0.67 (95% confidence interval (CI): 0.64-0.70). The highest positive predictive value (PPV) for the outcome of disease-free was 0.55 (95% CI: 0.41-0.68) at a suPAR of 1.65 ng/mL. Patients who died had significantly higher suPAR compared to patients who survived in all disease subgroups. The AUC of suPAR for 1-year mortality was 0.80 (95% CI: 0.77-0.83).

CONCLUSIONS

suPAR was significantly lower in disease-free individuals compared to patients with cancer or other conditions, but the PPV was not sufficiently high to terminate further clinical investigation with appropriate safety. Elevated suPAR may be a useful prognostic marker for adverse outcomes.

Effects of a highly controlled carbohydrate-reduced high-protein diet on markers of oxidatively generated nucleic acid modifications and inflammation in weight stable participants with type 2 diabetes; a randomized controlled trial

Carbohydrate-restricted diets are increasingly recognized as options for dietary management of type 2 diabetes mellitus (T2DM). We investigated the effects of a carbohydrate-reduced high-protein (CRHP) and a conventional diabetes (CD) diet on oxidative stress and inflammation in weight stable individuals with T2DM. We hypothesized that the CRHP diet would improve markers of oxidatively generated RNA and DNA modifications as well as inflammatory parameters. Thirty participants with T2DM were randomized to 6 weeks of CRHP or CD dietary treatment (30/50 energy percentage (E%) carbohydrate, 30/17E% protein, 40/33E% fat), followed by a cross-over to the opposite diet for a subsequent 6-week period. All meals were provided during the study and body weight was controlled. Diurnal urine samples were collected after 4 weeks on each diet and oxidatively generated RNA and DNA modifications were measured as 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), respectively. Fasting concentrations of soluble urokinase plasminogen activator receptor, high-sensitivity C-reactive protein, tumor necrosis factor alpha and interleukin-6 were measured before and after 6 weeks of interventions. Compared with the CD diet, the CRHP diet increased 24-hour urinary excretion of 8-oxoGuo by 9.3% (38.6 ± 12.6 vs. 35.3 ± 11.0 nmol/24 h, p = .03), whereas 8-oxodG did not differ between diets (24.0 ± 9.5 vs. 24.8 ± 11.1 nmol/24 h, p = .17). Changes in plasma inflammatory parameters did not differ between CRHP and CD diets, all p ≥ .2. The clinical implications of increased RNA oxidation following a CRHP diet as well as long-term effects of carbohydrate-restriction on markers of oxidatively generated nucleic acid modifications should be a field of future study.

Increased level of circulating cell-free mitochondrial DNA due to a single bout of strenuous physical exercise

Purpose

Physical exercise is reported to affect the immune response in various ways. Thus, the levels of pro-inflammatory cytokines as well as the abundance of circulating leukocytes are changed. In this study, the occurence of circulating cell-free mitochondrial DNA (cfmtDNA) and nuclear DNA (nDNA) was investigated in connection with a single bout of strenuous physical exercise.

Methods

Healthy volunteers performed a controlled ergo-spirometry cycle test and venous blood samples were taken at different time-points to analyze the concentration of blood components before, during and after the test. The number of circulating leukocytes was measured, as well as secretion of the soluble urokinase activator receptor (suPAR).

Results

Cf-mtDNA significantly increased during exercise, compared to baseline values and after 30 and 90 min of rest. Circulating leukocytes increased during exercise, but returned to baseline levels afterwards. Surface expression of the urokinase plasminogen activating receptor (uPAR) on neutrophils decreased significantly during exercise. The concentration of suPAR tended to increase during exercise but only significantly after 90 min of rest.

Conclusion

Increased concentration of cf-mtDNA indicates that cell damage takes place during high intensity training. Hypoxia and tissue damage are likely causes of cf-mtDNA from muscle cells. The levels of cf-mtDNA remain high during the initial rest, due to the decreasing numbers of leukocytes normally clearing the plasma from cf-mtDNA. The increased levels of suPAR further emphasize that strenuous physical exercise causes a reaction similar to inflammation. Further studies are needed to detect the source of increased cf-mtDNA and the corresponding increase of suPAR liberation.

Soluble urokinase-type plasminogen activator receptor represents exercise tolerance and predicts adverse cardiac events in patients with heart failure

Soluble urokinase-type plasminogen activator receptor (suPAR) is a membrane-binding protein that is released into the blood stream by immune activation. Recent reports suggest that circulating suPAR levels are associated with adverse cardiovascular outcomes. Exercise tolerance is an independent predictor of prognosis in patients with heart failure (HF); however, the relationship between serum suPAR level and exercise tolerance is unclear. We prospectively enrolled 94 patients who were hospitalized for worsening of HF. All patients underwent a symptom-limited cardiopulmonary exercise test to evaluate exercise tolerance. The median value of serum suPAR was 4848 pg/ml. During follow up, 44 patients (47%) were admitted for all-cause mortality and re-hospitalization for HF. Median serum suPAR was significantly higher in the patients with cardiac events than in the patients with non-event group. Patients were divided into two groups according to circulating suPAR levels. Kaplan-Meier analysis demonstrated that adverse cardiac events were significantly higher in the high suPAR group (log-rank p = 0.023). Multivariate analysis revealed that suPAR was independently correlated with the parameters of exercise tolerance such as anaerobic threshold (p = 0.007) and peak oxygen uptake (p = 0.005). suPAR levels predicted adverse cardiac events and independently correlated with the parameters of exercise tolerance. suPAR could be a useful surrogate biomarker of exercise tolerance in patients with HF.

The biomarkers suPAR and blood eosinophils are associated with hospital readmissions and mortality in asthma - a retrospective cohort study

Introduction

Prognostic biomarkers in asthma are needed. The biomarker soluble urokinase plasminogen activator receptor (suPAR) has been associated with asthma control and with prognosis in acutely admitted medical patients. We investigated if suPAR and blood eosinophil counts at the time of admission for asthma are associated with readmission and mortality.

Methods

Our cohort comprised 1341 patients (median age 45.3, IQR 30.1–63.1) acutely admitted with a diagnosis of asthma to Hvidovre Hospital, Denmark (November 2013 to March 2017). Patients had suPAR and blood eosinophils measured at admission. Outcomes were 365-day readmission and all-cause mortality. Logistic regression analysis adjusted for age, sex, C-reactive protein, and Charlson comorbidity score was used to assess the association of the two biomarkers with readmission and all-cause mortality.

Results

Compared to event-free patients, patients who were either readmitted (n = 452, 42.3%) or died (n = 57, 5.3%) had significantly higher suPAR concentrations (p < 0.0001) and lower eosinophil counts (p = 0.0031) at admission. The highest odds of readmission or mortality were observed for patients in either the 4th suPAR quartile (p < 0.0001) or with eosinophil counts < 150 cells/μL at admission. Increasing levels of suPAR were associated with 365-day readmission (OR 1.3 [1.0–1.6]; p = 0.05) and mortality (OR 2.9 [1.7–5.1]; p = 0.0002). Eosinophil count > 300 cells/μL was significantly associated with lower odds of readmission (OR 0.64 [0.5–0.9]; p = 0.005) and lower mortality (OR 0.7 [0.6–0.9]; p = 0.0007).

Conclusions

In patients acutely admitted with asthma, elevated suPAR concentrations together with blood eosinophil count < 150 cells/μL at the time of hospital admission were associated with both 365-day all-cause readmission and mortality.

Reproducibility of novel immune-inflammatory biomarkers over 4 months: an analysis with repeated measures design

Aim: Assessment of the feasibility and reliability of immune-inflammatory biomarker measurements. Methods: The following biomarkers were assessed in 207 predominantly healthy participants at baseline and after 4 months: MMF, TGF-β, suPAR and clusterin. Results: Intraclass correlation coefficients (95% CIs) ranged from good for TGF-β (0.75 [95% CI: 0.33-0.90]) to excellent for MMF (0.81 [95% CI: 0.64-0.90]), clusterin (0.83 [95% CI: 0.78-0.87]) and suPAR (0.91 [95% CI: 0.88-0.93]). Measurement of TGF-β was challenged by the large number of values below the detection limit. Conclusion: Single measurements of suPAR, clusterin and MMF could serve as feasible and reliable biomarkers of immune-inflammatory pathways in biomedical research.

Serum soluble urokinase plasminogen activator receptor (suPAR) in adults with growth hormone deficiency

Growth hormone deficiency (GHD) syndrome is associated with adverse levels of several risk factors for cardiovascular diseases (CVD), including metabolic inflammation. However, the impact of GHD and GH treatment on low-grade inflammation is unknown. The aim of the study was to establish the level of the low-grade inflammation biomarker soluble urokinase plasminogen activator receptor (suPAR) in adults with GHD and the response to long-term GH treatment. Measurements of suPAR and CRP were performed in bio-bank serum samples from 72 adults, 34 males and 38 females, with GHD before and during at least 5 years of GH treatment. Mean age was 52.5 ± 15.5 years, BMI 27.3 ± 5 kg/m2. Clinical evaluations and blood sampling were performed at routine visits. Data on demography, anthropometry, lab results and clinical events were retrieved from post-marketing surveillance study databases and medical records. suPAR and high-sensitive (hs) CRP were analysed using ELISA and immunochemistry, respectively. At baseline blood pressure, lipid profile and fasting glucose were within the normal reference range. Baseline geometric mean and 95% CI of suPAR was 2.9 (2.7-3.3) ng/mL and of CRP 2.3 (0.6-4.0) mg/L. Mean follow-up was 8 ± 2 years. The suPAR levels remained stable during follow-up, although individual increases were seen on occurrence or presence of co-morbidities. In contrast, levels of CRP decreased. In conclusion, the decrease in CRP and indirectly the absence of an expected increase in suPAR over time indicates a favourable effect of GH on low-grade inflammation.

Neutrophils are a main source of circulating suPAR predicting outcome in critical illness

Background

Circulating levels of soluble urokinase plasminogen activation receptor (suPAR) have been proposed as a prognostic biomarker in patients with critical illness and sepsis. However, the origin of suPAR in sepsis has remained obscure. We investigated the potential cellular sources of suPAR by analyzing membrane-bound urokinase plasminogen activator receptor (uPAR, CD87) and evaluated its clinical relevance in critically ill patients.

Methods

We studied 87 critically ill patients (44 with sepsis, 43 without sepsis) from the medical intensive care unit (ICU) in comparison to 48 standard care patients with infections and 27 healthy controls in a prospective single-center non-interventional cohort study. Cellular uPAR expression of different immune cell subsets (by flow cytometry from peripheral blood) and corresponding serum suPAR concentrations were determined upon ICU admission and at day 3. Furthermore, we analyzed the effects of serum from sepsis patients on the activation and uPAR cleavage of primary human neutrophils and macrophages in vitro.

Results

In healthy controls, uPAR (CD87) expression was detected on nearly all blood neutrophils and monocytes, but only scarcely on lymphocytes. While uPAR expression on monocytes was maintained in ICU patients, only 58% of neutrophils from critically ill patients expressed uPAR, which was significantly lower than in healthy controls or standard care patients. Concomitantly, serum suPAR levels were significantly increased in ICU patients. We noted a clear inverse correlation between low neutrophilic uPAR and high serum suPAR in standard care and ICU patients, indicating that shedding of uPAR from activated neutrophils represents a main source of suPAR in systemic inflammation. Both low uPAR and high suPAR were closely associated with mortality in critically ill patients. Furthermore, serum from sepsis patients induced uPAR protein expression and subsequent receptor shedding on isolated primary neutrophils, but not on macrophages, in vitro.

Conclusions

The inverse correlation between low uPAR surface expression on neutrophils and high serum suPAR in critically ill patients supports that neutrophils are a main source of shed suPAR proteins in systemic inflammation. Furthermore, high suPAR levels and low neutrophilic uPAR expression predict mortality in ICU patients.

Electronic supplementary material

The online version of this article (10.1186/s40560-019-0381-5) contains supplementary material, which is available to authorized users.