The intriguing role of soluble urokinase receptor in inflammatory diseases

Blood biomarker discovery for autism spectrum disorder: A proteomic analysis

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and social interaction and restricted, repetitive patterns of behavior, interests, or activities. Given the lack of specific pharmacological therapy for ASD and the clinical heterogeneity of the disorder, current biomarker research efforts are geared mainly toward identifying markers for determining ASD risk or for assisting with a diagnosis. A wide range of putative biological markers for ASD are currently being investigated. Proteomic analyses indicate that the levels of many proteins in plasma/serum are altered in ASD, suggesting that a panel of proteins may provide a blood biomarker for ASD. Serum samples from 76 boys with ASD and 78 typically developing (TD) boys, 2-10 years of age, were analyzed to identify possible early biological markers for ASD. Proteomic analysis of serum was performed using SomaLogic's SOMAScanTM assay 1.3K platform. A total of 1,125 proteins were analyzed. There were 86 downregulated proteins and 52 upregulated proteins in ASD (FDR < 0.05). Combining three different algorithms, we found a panel of 12 proteins that identified ASD with an area under the curve (AUC) = 0.8790±0.0572, with specificity and sensitivity of 0.8530±0.1076 and 0.8324±0.1137, respectively. All 12 proteins were significantly different in ASD compared with TD boys, and 4 were significantly correlated with ASD severity as measured by ADOS total scores. Using machine learning methods, a panel of serum proteins was identified that may be useful as a blood biomarker for ASD in boys. Further verification of the protein biomarker panel with independent test sets is warranted.

Physical exercise, systemic inflammation and adult-onset asthma: a 12-year follow-up study

Objective: Physical exercise in treatment of asthma is scarcely studied with no clear exercise guidelines for asthmatics. We aimed to investigate the associations between physical exercise frequency, systemic inflammation and asthma control. This has not been previously studied in adult-onset asthma.

Methods: This study is part of Seinäjoki Adult Asthma Study (SAAS), where 203 patients with adult-onset asthma were evaluated in 2012-2013. Exercise frequency was recorded with a structured lifestyle questionnaire. Study population was divided into two categories by exercise frequency: Low-frequency group exercised ≤2 times/week and high frequency group >2 times/week. Blood inflammatory markers were measured and IL-6 > 1.55 pg/ml and hs-CRP > 4.12 mg/l indicated systemic inflammation.

Results: High-exercise frequency group had lower levels of hs-CRP (p = 0.007), IL-6 (p = 0.015), suPAR (p = 0.008) and adipsin (p = 0.031) and higher levels of adiponectin (p = 0.010) than low-exercise frequency group. In logistic multivariate regression models, higher-exercise frequency lowered odds for elevated hs-CRP (OR = 0.37, 95% CI 0.15-0.94) and IL-6 levels (OR = 0.43, 95% CI 0.20-0.91), after adjusting for possible confounding factors. There was no difference in lung function tests, asthma control test or airways questionnaire 20 scores between the exercise frequency groups. However, differences were found in single symptom questions; high-exercise frequency group had less symptoms during light housework and laughing but experienced more limitation of activity in self-reports.

Conclusions: Higher-exercise frequency is associated with lower level of systemic inflammation in patients with adult-onset asthma but no clear association was found to asthma outcomes. Exercise frequency may be associated with lesser amount of some individual asthma symptoms.

Clinical value of soluble urokinase-type plasminogen activator receptor in predicting sepsis-associated acute kidney injury

BACKGROUND

Sepsis-associated acute kidney injury (S-AKI) is a critical illness and is often associated with high morbidity and mortality rates. The soluble urokinase-type plasminogen activator receptor (suPAR) is an important immune mediator and is involved in kidney injury. However, its diagnostic value in S-AKI patients remains unclear. Therefore, we assessed the early predictive value of suPAR for S-AKI patients.

METHODS

We prospectively enrolled adult patients, immediately after fulfilling the sepsis-3 criteria. Plasma suPAR levels at 0-, 12-, 24-, and 48-h post-sepsis diagnosis were measured. S-AKI development was the primary outcome. S-AKI risk factors were analyzed using logistic regression, and the value of plasma suPAR for early S-AKI diagnosis was assessed using receiver operating characteristic (ROC) curves.

RESULTS

Of 179 sepsis patients, 63 (35.2%) developed AKI during hospitalization. At 12-, 24-, and 48-h post-sepsis diagnosis, plasma suPAR levels were significantly higher in patients with S-AKI than in patients without S-AKI (p < 0.05). The plasma suPAR had the highest area under the ROC curve of 0.700 (95% confidence interval (CI), 0.621-0.779) at 24-h post-sepsis diagnosis, at which the best discrimination ability for S-AKI was achieved with suPAR of ≥6.31 ng/mL (sensitivity 61.9% and specificity 71.6%). Logistic regression analysis showed that suPAR at 24-h post-sepsis diagnosis remained an independent S-AKI risk factor after adjusting for mechanical ventilation, blood urea nitrogen, and pH.

CONCLUSIONS

The findings suggest that plasma suPAR may be a potential biomarker for early S-AKI diagnosis.

Pulmonary Congestion and Anemia in Hemodialysis: The Potential Link to Inflammation

Pulmonary congestion (PC) is common in hemodialysis (HD) patients. We explored the association of anemia and pulmonary congestion in HD patients. A prospective pilot observational study included 18 patients on maintenance HD. Individual B-lines scores (BLS; 8-sites method) were obtained by lung ultrasound, before and after the first two consecutive HD sessions of the week (HD1-HD2), with different inter-dialytic intervals (68 vs. 44 h). Bioimpedance spectroscopy body composition (BIS) was performed before each HD session. Hemoglobin (Hb) levels, in addition to circulating markers of chronic inflammation (soluble urokinase Plasminogen Activator Receptor [suPAR], soluble Suppression of Tumorigenicity 2 [sST2]) were obtained. Mean (±SD) BLS values were quite elevated at all time points: Pre-HD1 (16 ± 5.53), post-HD1 (15.3 ± 6.63), pre-HD2 (16.3 ± 5.26) and post-HD2 (13.6 ± 5.83), respectively. No direct significant correlation was found between inflammation markers levels and BLS. However, mean levels (±SD, ng/mL) of suPAR pre-HD1 (7.88 ± 3.07) and pre-HD2 (7.78 ± 3.02) remained significantly above the normal range (<4 ng/mL), and sST2 levels reached 2-fold the upper normal value in most patients (27.4 ± 17.8). Pulmonary congestion reflected by BLS was negatively correlated to Hb levels pre-HD1 (R² = 0.439, p = 0.003), and pre-HD2 (R² = 0.301, p = 0.018). In addition, Hb levels were negatively correlated to global volume status estimated by BIS (R² = 0.351, p = 0.009). Hemoglobin levels were negatively correlated to pulmonary congestion and to the global volume status evaluated by BIS. Chronic inflammation markers were increased in HD patients, suggesting a complex volume- and non-volume-dependent pathophysiology of pulmonary congestion in HD patients.

Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR), Growth Differentiation Factor-15 (GDF-15), and Soluble C5b-9 (sC5b-9) Levels Are Significantly Associated with Endothelial Injury Indices in CAR-T Cell Recipients

Endothelial injury indices, such as Endothelial Activation and Stress Index (EASIX), modified EASIX (m-EASIX), and simplified EASIX (s-EASIX) scores, have been previously associated with chimeric antigen receptor-T (CAR-T) cell immunotherapy complications. Soluble urokinase-type plasminogen activator receptor (suPAR), growth differentiation factor-15 (GDF-15), and soluble C5b-9 (sC5b-9) have been described as markers of endothelial injury post-hematopoietic stem cell transplantation. In the current study, we examined whether suPAR, GDF-15, and sC5b-9 levels were associated with endothelial injury indices in adult CAR-T cell recipients. The levels of these markers were measured in patients before CAR-T cell infusion and in healthy individuals with immunoenzymatic methods. We studied 45 CAR-T cell recipients and 20 healthy individuals as the control group. SuPAR, GDF-15, and sC5b-9 levels were significantly higher in the patients' group compared to the healthy control group (p < 0.001, in all comparisons). SuPAR levels at baseline were associated with the m-EASIX scores calculated at the same time point (p = 0.020), while suPAR and GDF-15 concentrations were correlated with EASIX scores at day 14 post-infusion (p < 0.001 in both comparisons). Moreover, sC5b-9 levels were correlated with the s-EASIX scores at infusion (p = 0.008) and the EASIX scores at day 14 (p = 0.005). In our study, sC5b9, suPAR, and GDF-15 levels were found to reflect endothelial injury in CAR-T cell recipients.

Post-COVID-19 Multisystem Inflammatory Syndrome in Adults (MIS-A) With Elevated Levels of Soluble Urokinase Plasminogen Activator Receptor (suPAR) Treated With Anakinra: A Case Report

The COVID-19 pandemic has brought attention to a newly identified syndrome of multisystem inflammation. This potentially fatal complication of the disease was initially observed in children and later in adults. It affects primarily unvaccinated patients and may manifest within a timeframe of 2-12 weeks following infection. Soluble urokinase plasminogen activator receptor (suPAR), a novel biomarker, highlights the severity of inflammation and the degree of immune system activation. Herein, we report a case of a patient with multisystem inflammatory syndrome in adults (MIS-A) and markedly elevated suPAR levels, successfully treated with interleukin-1 (IL-1) receptor antagonist. A 59-year-old female was admitted to our hospital due to febrile illness (up to 40°C) with chills, vomiting, non-bloody diarrhea, and abdominal pain for four days prior to her admission. She tested positive for SARS-CoV-2 12 weeks before her presentation. During hospitalization, the patient deteriorated clinically with multiorgan involvement and hemodynamically instability, with concomitant markedly elevated inflammatory markers. Extensive workup with high suPAR levels led to post-COVID-19 MIS-A diagnosis, and treatment with dexamethasone and an interleukin-1 receptor antagonist (IL-1ra), anakinra, was administered. The subcutaneous injection of anakinra effectively and safely deterred MIS-A. Further research is needed to investigate the role of interleukin-1 inhibitors for the management of this potentially life-threatening condition.

Prognostic role of suPAR in acute pancreatitis: A protocol for systematic review

BACKGROUND

Acute pancreatitis (AP) is a common emergency condition with high morbidity, mortality, and socio-economic impact. Soluble urokinase plasminogen activator receptor (suPAR) is a potential biomarker for AP prognosis. This study systematically reviews the literature on suPAR's prognostic roles in assessing AP severity, organ failure, mortality, and other pathological markers.

METHODS

A comprehensive search of 5 databases up to March 19, 2023, was conducted, selecting cohort studies that examined suPAR's relationship with AP outcomes. Outcome variables included AP severity, organ failure, mortality, hospital stay length, and suPAR's association with other inflammatory markers. Our paper has been registered on Prospero (ID: CRD42023410628).

RESULTS

Nine prospective observational studies with 1033 AP patients were included. Seven of eight studies found suPAR significantly elevated in severe acute pancreatitis (P < .05). Four studies showed suPAR effectively predicted organ failure risk, and 4 studies concluded suPAR significantly predicted mortality (P < .05). The review had no high-risk studies, enhancing credibility.

CONCLUSION

suPAR is a valuable prognostic marker in AP, significantly predicting severity, organ failure, hospital stay length, and mortality. Further large-scale studies are needed to explore suPAR's role in other clinical outcomes related to AP disease course, to establish it as a mainstay of AP prognosis.

Point-of-Care Serum Proenkephalin as an Early Predictor of Mortality in Patients Presenting to the Emergency Department with Septic Shock

BACKGROUND

The aim of the present study is to investigate the prognostic utility of point-of-care (POC)-measured proenkephalin (PENK), a novel biomarker, in terms of predicting in-hospital mortality in patients presenting to the emergency department (ED) with septic shock.

METHODS

Bedside PENK was measured in consecutive patients presenting to the ED with septic shock according to the Sepsis-3 clinical criteria. The association of PENK with inflammatory and routine biomarkers, and its role as a predictor of in-hospital mortality, was examined.

RESULTS

Sixty-one patients with septic shock [53% females, median age 83 years (IQR 71-88)] were evaluated. Median (IQR) values of creatinine, plasma lactate, soluble urokinase plasminogen activator receptor (SuPAR), procalcitonin and PENK were 1.7 (1.0-2.9) mg/dL, 3.6 (2.1-6.8) mmol/L, 13.1 (10.0-21.4) ng/mL, 2.06 (0.84-3.49) ng/mL, and 205 (129-425) pmol/L, respectively. LogPENK significantly correlated with LogLactate (rho = 0.369, p = 0.004), LogCreatinine (rho = 0.537, p < 0.001), LogProcalcitonin (rho = 0.557, p < 0.001), and LogSuPAR (rho = 0.327, p = 0.011). During hospitalization, 39/61 (64%) patients died. In a multivariable logistic regression model, logPENK was an independent predictor of in-hospital mortality (OR 11.9, 95% CI: 1.7-84.6, p = 0.013).

CONCLUSION

POC PENK levels measured upon presentation to the ED strongly correlated with metabolic, renal and inflammatory biomarkers, and may serve as a predictor of in-hospital mortality in patients with septic shock.

Establishing reference intervals for soluble urokinase plasminogen activator receptor in Northern European adults

Objectives

Soluble urokinase plasminogen activator receptor (suPAR) may have untapped potential in clinical diagnostics. Previous studies determined reference intervals using an enzyme-linked immunoassay, but there is a need for reference intervals using a faster assay if the analysis is to be used in emergency medicine. The current study aims to determine reference intervals for suPAR using a fully automated particle-enhanced turbidimetric immunoassay (PETIA) according to the Clinical and Laboratory Standards Institute guideline A28-A3c.

Design and methods

Blood samples were prospectively collected from Danish blood donors. Plasma suPAR was analyzed on the cobas 8000 module c502 in an open channel using a PETIA. Sex-partitioned reference intervals were determined using a parametric quantile approach.

Results

The study included 241 participants-123 females and 118 males. The common reference interval for suPAR was 1.56-4.11 ng/mL (95% confidence intervals (CI) for the lower and upper limits were 1.56-1.63 and 3.81-4.47, respectively). The reference interval for females was 1.59-4.65 ng/mL (95% CIs 1.48-1.70 and 4.09-5.48, respectively) and for males, 1.56-3.59 ng/mL (95% CIs 1.47-1.65 and 3.31-3.93, respectively).

Conclusions

Our results support using sex-partitioned reference intervals for suPAR and provide a basis for future studies using the PETIA method.

Evaluation of New Cardiac Damage Biomarkers in Polytrauma: GDF-15, HFABP and uPAR for Predicting Patient Outcomes

Background: Polytrauma is one of the leading mortality factors in younger patients, and in particular, the presence of cardiac damage correlates with a poor prognosis. Currently, troponin T is the gold standard, although troponin is limited as a biomarker. Therefore, there is a need for new biomarkers of cardiac damage early after trauma. Methods: Polytraumatized patients (ISS ≥ 16) were divided into two groups: those with cardiac damage (troponin T > 50 pg/mL, n = 37) and those without cardiac damage (troponin T < 12 pg/mL, n = 32) on admission to the hospital. Patients' plasma was collected in the emergency room 24 h after trauma, and plasma from healthy volunteers (n = 10) was sampled. The plasma was analyzed for the expression of HFABP, GDF-15 and uPAR proteins, as well as miR-21, miR-29, miR-34, miR-122, miR-125b, miR-133, miR-194, miR-204, and miR-155. Results were correlated with patients' outcomes. Results: HFABP, uPAR, and GDF-15 were increased in polytraumatized patients with cardiac damage (p < 0.001) with a need for catecholamines. HFABP was increased in non-survivors. Analysis of systemic miRNA concentrations showed a significant increase in miR-133 (p < 0.01) and miR-21 (p < 0.05) in patients with cardiac damage. Conclusion: All tested plasma proteins, miR-133, and miR-21 were found to reflect the cardiac damage in polytrauma patients. GDF-15 and HFABP were shown to strongly correlate with patients' outcomes.

Soluble urokinase plasminogen activator receptor (suPAR) in bronchoalveolar fluid and blood in critically ill patients-a prospective cohort study

INTRODUCTION

Soluble urokinase plasminogen activator receptor (suPAR) is a biologically active protein and increased levels are associated with worse outcomes in critically ill patients. suPAR in bronchoalveolar fluid (BALF) may be helpful to differentiate between types of acute respiratory distress syndrome (ARDS) and may have potential for early detection of fungal infection.

METHODS

We prospectively investigated levels of suPAR in BALF and serum in critically ill patients who underwent bronchoscopy for any reason at the ICU of the Department of Internal Medicine, Medical University of Graz, Graz, Austria.

RESULTS

Seventy-five patients were available for analyses. Median age was 60 [25th-75th percentile: 50-69] years, 27% were female, and median SOFA score was 12 [11-14] points. Serum suPAR levels were significantly associated with ICU mortality in univariable logistic regression analysis. There was no correlation between BALF and serum suPAR. Serum suPAR was higher in ARDS patients at 11.2 [8.0-17.2] ng/mL compared to those without ARDS at 7.1 [3.7-10.1] (p < 0.001). BALF-suPAR was significantly higher in patients with evidence of fungal lung infection compared to patients without fungal infection both in the general cohort (7.6 [3.2-9.4] vs 2.5 [1.1-5.3], p = 0.013) and in the subgroup of ARDS (7.2 [3.1-39.2] vs 2.5 [1.0-5.2], p = 0.022). All patients were classified as putative/probable invasive aspergillosis.

CONCLUSION

We found significant higher levels of serum suPAR in ARDS patients compared to those not fulfilling ARDS criteria. Serum and BALF-suPAR were significantly higher in those patients with evidence for invasive pulmonary aspergillosis. These findings may suggest testing this biomarker for early diagnosis of fungal infection in a greater cohort.

Role of Formyl Peptide Receptors and β-Arrestin-1 in suPAR Signal Transduction in Mouse Podocytes: Interactions with αVβ3-Integrin

The soluble urokinase plasminogen activator receptor (suPAR) has been implicated in a wide range of pathological conditions including primary nephrotic syndromes and acute kidney injuries. suPAR can trigger transduction cascades in podocytes by outside-in activation of αVβ3-integrin, but there is evidence that the functional cell surface response element is actually a complex of different types of receptors, which may also include the receptor for advanced glycation end-products (RAGE) and formyl peptide receptors (FPRs). Here we observed that ROS accumulation and Src activation could be evoked by continuous 24 h exposure to either suPAR or the FPR agonist fMLF. Responses to suPAR and fMLF were completely blocked by either the FPR antagonist WRW4 or by the αV-integrin inhibitor cilengitide. Moreover, endogenous podocyte mouse Fpr1 co-immunoprecipitates with β3-integrin, suggesting that these receptors occur as a complex on the cell surface. suPAR- and fMLF-evoked activation of Src and ROS differed in time course. Thus, robust pertussis toxin (PTX)-sensitive responses were evoked by 60 min exposures to fMLF but not to suPAR. By contrast, responses to 24 h exposures to either suPAR or fMLF were PTX-resistant and were instead abolished by knockdown of β-arrestin-1 (BAR1). FPRs, integrins, and RAGE (along with various Toll-like receptors) can all function as pattern-recognition receptors that respond to "danger signals" associated with infections and tissue injury. The fact that podocytes express such a wide array of pattern-recognition receptors suggests that the glomerular filter is designed to change its function under certain conditions, possibly to facilitate clearance of toxic macromolecules.

Soluble urokinase plasminogen activator receptor in vaginally collected amniotic fluid predicting fetal inflammatory response syndrome: a prospective cohort study

BACKGROUND

Improving noninvasive antenatal diagnosis of fetal inflammatory response syndrome (FIRS) can assist in the evaluation of prenatal risk and reduce perinatal outcomes. This study aimed to determine whether soluble urokinase-type plasminogen activator receptor (suPAR) in vaginally collected amniotic fluid is significant in identifying FIRS after preterm premature rupture of membranes before 34 weeks of gestation.

METHODS

This was a prospective cohort study of 114 pregnant women and their newborns after preterm premature rupture of membranes at 22-34+6 weeks of gestation. SuPAR was evaluated using an enzyme-linked immunosorbent assay in vaginally collected amniotic fluid. Patients were classified according to the presence or absence of FIRS. FIRS was defined by umbilical cord blood interleukin-6 level > 11 pg/mL or histological funisitis. The data were analyzed using the R package (R-4.0.5).

RESULTS

SuPAR was detected in all amniotic fluid samples with a median of 26.23 ng/mL (interquartile range (IQR), 15.19-51.14). The median level of suPAR was higher in the FIRS group than in the non-FIRS group, 32.36 ng/mL (IQR, 17.27-84.16) vs. 20.46 ng/mL (IQR, 11.49-36.63) (P = 0.01), respectively. The presence of histological chorioamnionitis significantly increased the suPAR concentration in the FIRS group (P < 0.001). The areas under the curve for FIRS and FIRS with histological chorioamnionitis were 0.65 and 0.74, respectively, with an optimum cutoff value of 27.60 ng/mL. Controlling for gestational age, the cutoff of suPAR more than 27.60 ng/mL predicted threefold higher odds for FIRS and sixfold higher odds for FIRS with histologic chorioamnionitis.

CONCLUSION

Soluble urokinase-type plasminogen activator receptor in vaginally obtained amniotic fluid may assist in evaluating prenatal risk of FIRS in patients after preterm premature rupture of membranes before 34 weeks of gestation.

Gene Association Study of the Urokinase Plasminogen Activator and Its Receptor Gene in Alzheimer's Disease

Background

The role of the innate immune system has long been associated with Alzheimer's disease (AD). There is now accumulating evidence that the soluble Urokinase Plasminogen Activator Receptor pathway, and its genes, PLAU and PLAUR may be important in AD, and yet there have been few genetic association studies to explore this.

Objective

This study utilizes the DNA bank of the Brains for Dementia Research cohort to investigate the genetic association of common polymorphisms across the PLAU and PLAUR genes with AD.

Methods

TaqMan genotyping assays were used with standard procedures followed by association analysis in PLINK.

Results

No association was observed between the PLAU gene and AD; however, two SNPs located in the PLAUR gene were indicative of a trend towards association but did not surpass multiple testing significance thresholds.

Conclusions

Further genotyping studies and exploration of the consequences of these SNPs on gene expression and alternative splicing are warranted to fully uncover the role this system may have in AD.

suPARnostic: an advanced predictive tool for detecting recurrence in renal cell carcinoma

BACKGROUND

Plasma soluble urokinase-type Plasminogen Activator Receptor (suPAR) predicts disease aggressiveness in renal cell carcinoma (ccRCC), but its prognostic accuracy has not been investigated. To investigate the prognostic accuracy of preoperative plasma suPAR in patients who received curative treatment for initially localized ccRCC.

METHODS

We retrospectively analyzed plasma samples stored in the Danish National Biobank between 2010 and 2015 from 235 patients with ccRCC at any stage. Relationships with outcome analyzed using univariate and multiple logistic Cox regression analysis.

RESULTS

There were 235 patients with ccRCC. The median follow-up period was 7.7 years. In univariate analysis suPAR ≥ 6 ng/mL was significantly associated with overall survival (OS) and recurrence-free survival (RFS). Patients with elevated suPAR were more likely to recur, with a Hazard Ratio (HR) of 2.3 for RFS. In multiple logistic regression, suPAR ≥ 6 ng/mL remained a negative predictor of OS and RFS. Limitations include retrospective study design, wide confidence intervals, and tumor subtype heterogeneity bias.

CONCLUSIONS

ccRCC patients with high plasma suPAR concentrations are at an elevated risk of disease recurrence and see lower OS. suPAR is a promising surveillance tool to more precisely follow up with ccRCC patients and detect future recurrences. In this study, we showed that new type of liquid marker in blood plasma, called suPAR, is associated to a higher risk of kidney cancer recurrence when elevated above 6ng/mL. We also showed suPAR to independently be able to predict patients overall and recurrence free survival in patient with any stage of kidney cancer.

Soluble Urokinase Plasminogen Activator Receptor (suPAR) in Autoimmune Rheumatic and Non Rheumatic Diseases

The soluble urokinase plasminogen activator receptor (suPAR) is the bioactive form of uPAR, a membrane-bound glycoprotein, and it is primarily expressed on the surface of immunologically active cells. Mirroring local inflammation and immune activation, suPAR has gained interest as a potential prognostic biomarker in several inflammatory diseases. Indeed, in many diseases, including cancer, diabetes, cardiovascular diseases, kidney diseases, and inflammatory disorders, higher suPAR concentrations have been associated with disease severity, disease relapse, and mortality. Our review describes and discusses the supporting literature concerning the promising role of suPAR as a biomarker in different autoimmune rheumatic and non-rheumatic diseases.

Milk intake, lactase persistence genotype, plasma proteins and risks of cardiovascular events in the Swedish general population

To investigate the associations of milk intake (non-fermented and fermented milk), lactase persistence (LCT-13910 C/T) genotype (a proxy for long-term non-fermented milk intake), and gene-milk interaction with risks of cardiovascular disease (CVD) and CVD mortality. Also, to identify the CVD-related plasma proteins and lipoprotein subfractions associated with milk intake and LCT-13910 C/T genotype. The prospective cohort study included 20,499 participants who were followed up for a mean of 21 years. Dietary intake was assessed using a modified diet history method. Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). After adjusting for sociodemographic and lifestyle factors, higher non-fermented milk intake was significantly associated with higher risks of coronary heart disease (CHD) and CVD mortality, whereas higher fermented milk intake was significantly associated with lower risks of CVD and CVD mortality. The genotype associated with higher milk (mainly non-fermented) intake was positively associated with CHD (CT/TT vs. CC HR = 1.27; 95% CI: 1.03, 1.55) and CVD (HR = 1.22; 95% CI: 1.05, 1.42). The association between rs4988235 genotype and CVD mortality was stronger in participants with higher milk intake than among participants with lower intake (P for interaction < 0.05). Furthermore, leptin, HDL, and large HDL were associated with non-fermented milk intake, while no plasma proteins or lipoprotein subfractions associated with fermented milk intake and LCT-13910 C/T genotype were identified. In conclusion, non-fermented milk intake was associated with higher risks of CHD and CVD mortality, as well as leptin and HDL, whereas fermented milk intake was associated with lower risks of CVD and CVD mortality.

Early Life Stress, Neuroinflammation, and Psychiatric Illness of Adulthood

Stress exposure during early stages of life elevates the risk of developing psychopathologies and psychiatric illness in later life. The brain and immune system are not completely developed by birth and therefore continue develop after birth; this post birth development is influenced by several psychosocial factors; hence, early life stress (ELS) exposure can alter brain structural development and function. A growing number of experimental animal and observational human studies have investigated the link between ELS exposure and increased risk of psychopathology through alternations in the immune system, by evaluating inflammation biomarkers. Recent studies, including brain imaging, have also shed light on the mechanisms by which both the innate and adaptive immune systems interact with neural circuits and neurotransmitters, which affect psychopathology. Herein, we discuss the link between the experience of stress in early life and lifelong alterations in the immune system, which subsequently lead to the development of various psychiatric illnesses.

Ability of combined soluble urokinase plasminogen activator receptor to predict preventable emergency attendance in older patients in Japan: a prospective pilot study

Soluble urokinase plasminogen activator receptor (suPAR) is a strong and nonspecific inflammatory biomarker that reflects various immunologic reactions, organ damage, and risk of mortality in the general population. Although prior research in acute medical patients showed that an elevation in suPAR is related to intensive care unit admission and risk of readmission and mortality, no studies have focused on the predictive value of suPAR for preventable emergency attendance (PEA). This study aims to evaluate the predictive value of suPAR, which consists of a combination of white blood cell count (WBC), C-reactive protein (CRP), and the National Early Warning Score (NEWS), for PEA in older patients (>65 years) without trauma who presented to the emergency department (ED). This single-center prospective pilot study was conducted in the ED of the Association of EISEIKAI Medical and Healthcare Corporation Minamitama Hospital, in Hachiouji City, Tokyo, Japan, from September 16, 2020, to June 21, 2022. The study included all patients without trauma aged 65 years or older who were living in their home or a facility and presented to the ED when medical professionals decided an emergency consultation was required. Discrimination was assessed by plotting the receiver-operating characteristic (ROC) curve and calculating the area under the ROC curve (AUC). During the study period, 49 eligible older patients were included, and thirteen (26.5%) PEA cases were detected. The median suPAR was significantly lower in the PEA group than in the non-PEA group (p < 0.05). For suPAR, the AUC for the prediction of PEA was 0.678 (95% CI 0.499-0.842, p < 0.05), and there was no significant difference from other variables as follows: 0.801 (95% CI 0.673-0.906, p < 0.001) for WBC, 0.833 (95% CI 0.717-0.934, p < 0.001) for CRP, and 0.693 (95% CI 0.495-0.862, p < 0.05) for NEWS. Furthermore, the AUC for predicting PEA was 0.867 (95% CI 0.741-0.959, p < 0.001) for suPAR + WBC + CRP + NEWS, which was significantly higher than that of the original suPAR (p < 0.01). The cutoff values, sensitivity, specificity, and odds ratio of suPAR and suPAR + WBC + CRP + NEWS were 7.5 and 22.88, 80.6% and 83.3%, 53.8% and 76.9%, and 4.83 and 16.67, respectively. This study has several limitations. First, this was pilot study, and we included a small number of older patients. Second, the COVID-19 pandemic occurred during the study period, so that there may be selection bias in the study population. Third, our hospital is a secondary emergency medical institution, and as such, we did not treat very fatal cases, which could be another cause of selection bias. Our single-center study has demonstrated the moderate utility of the combined suPAR as a triage tool for predicting PEA in older patients without trauma receiving home medical care. Before introducing suPAR to the prehospital setting, evidence from multicenter studies is needed.

Higher Cerebrospinal Fluid Soluble Urokinase-type Plasminogen Activator Receptor, But Not Interferon γ-inducible Protein 10, Correlate With Higher Working Memory Deficits

BACKGROUND

We hypothesized that the induction of monocyte activation biomarkers, especially soluble urokinase-type plasminogen activator receptor (suPAR) and interferon γ-inducible protein 10 (IP-10), is lower in HIV-1C than HIV-1B, owing to a defective Tat cysteine dimotif (C30S).

METHODS

A total of 68 paired cerebrospinal fluid (CSF) and blood samples from people with HIV (PWH), free of CNS opportunistic infections, from a Southern Brazil outpatient HIV clinic were evaluated such as HIV-1B subtype (n = 27), HIV-1C (n = 26), other (n = 15), and 19 HIV-negative controls. The levels of suPAR, IP-10, neopterin, and β2 microglobulin (β2m) in the CSF and serum were quantified using different immunoassays.

RESULTS

Overall, in PWH, increases in CSF suPAR, CSF/serum suPAR, and CSF/serum β2m correlated with worse working memory deficits (r = 0.303, 0.353, and 0.289, respectively, all P < 0.05). The medians of IP-10, suPAR, neopterin, and β2m in CSF and serum and the CSF/serum ratio and suPAR index were comparable between the HIV-1B and HIV-1C subtypes. CSF IP-10 and neopterin and serum IP-10 and suPAR levels were higher in PWH than the HIV-negative controls (P = 0.015, P = 0.001, P < 0.0001, and P < 0.001, respectively). The serum β2m level was higher in HIV-associated dementia than neuropsychologically normal or asymptomatic (P = 0.024).

DISCUSSION

We observed that higher levels of CSF suPAR and the suPAR quotient correlated with worse working memory deficit. Elevated levels of monocyte activation were similar in both HIV-1 B and C subtypes, providing no evidence of reduced neuropathogenicity of HIV-1 subtype C Tat compared with subtype B.

Crystal structure and cellular functions of uPAR dimer

Receptor dimerization of urokinase-type plasminogen activator receptor (uPAR) was previously identified at protein level and on cell surface. Recently, a dimeric form of mouse uPAR isoform 2 was proposed to induce kidney disease. Here, we report the crystal structure of human uPAR dimer at 2.96 Å. The structure reveals enormous conformational changes of the dimer compared to the monomeric structure: D1 of uPAR opens up into a large expanded ring that captures a β-hairpin loop of a neighboring uPAR to form an expanded β-sheet, leading to an elongated, highly intertwined dimeric uPAR. Based on the structure, we identify E49P as a mutation promoting dimer formation. The mutation increases receptor binding to the amino terminal fragment of its primary ligand uPA, induces the receptor to distribute to the basal membrane, promotes cell proliferation, and alters cell morphology via β1 integrin signaling. These results reveal the structural basis for uPAR dimerization, its effect on cellular functions, and provide a basis to further study this multifunctional receptor.

Case–Control Study on Exercise-Induced Vasculitis in Hikers

The aim of this study was to identify clinical factors associated with exercise-induced vasculitis (EIV). This study included EIV cases and controls matched for age. Cases included were all members of a hiking club and participated in extended hiking trips. Exercise-induced vasculitis was diagnosed based on clinical signs occurring only after prolonged walks. Chronic venous disease was defined using the Clinical Etiological Anatomical Pathophysiologic classification. This study included 162 hikers: 32 EIV cases and 130 matched controls. Mean age at EIV diagnosis was 47.1 years and 24 (75.0%) of EIV cases were women. Chronic venous disease was present in 19 (57.6%) of EIV cases vs 39 (30.0%) in controls ( P = .001); those with EIV had significantly more saphenous vein insufficiency and C3 venous insufficiency than controls, 85.0 vs 52.6% and 8 (25.0%) vs 13 (10.0%) ( P = .02), respectively. For EIV cases, mean walking distance per hike was significantly higher than for controls ( P = .002). Exercise-induced vasculitis symptoms were typical with rash and/or purpura on the leg in warm conditions. Lesions spontaneously disappear in <10 days. In this study, EIV cases had more chronic venous disease and longer mean walking distances than controls.

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.

Review of cadmium exposure and smoking-independent effects on atherosclerotic cardiovascular disease in the general population

BACKGROUND

Exposure to cadmium (Cd) via food and smoking is associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Blood and urine levels of Cd are established biomarkers of exposure.

OBJECTIVES

To review (1) the smoking-independent associations between Cd exposure and ASCVD, including the possible presence of a nonlinear dose-response relationship with Cd exposure and (2) the causal effects of Cd exposure on different stages of atherosclerosis.

METHODS

Narrative review.

RESULTS

Cd confers increased risk of ASCVD and asymptomatic atherosclerosis in the carotid and coronary arteries above B-Cd >0.5 μg/L or U-Cd >0.5 μg/g creatinine, but it has not been shown below a threshold of these exposure levels. Adjustment for smoking does not exclude the possibility of residual confounding, but several studies in never-smoking cohorts have shown associations between Cd and ASCVD, and experimental studies have demonstrated pro-atherosclerotic effects of Cd. Cd accumulates in arterial walls and atherosclerotic plaques, reaching levels shown to have proatherosclerotic effects. Suggested early effects are increased subendothelial retention of atherogenic lipoproteins, which become oxidized, and endothelial dysfunction and damage with increased permeability for monocytes, which in the intima turn to macrophages and then to foam cells. Later, Cd may contribute to plaque rupture and erosion by endothelial apoptosis and degradation of the fibrous cap. Finally, by having prothrombotic and antifibrinolytic effects, the CVD risk may be further increased.

CONCLUSIONS

There is strong evidence that Cd causes ASCVD above a suggested exposure level via mechanisms in early as well as the late stages of atherosclerotic disease.

Associations between childhood victimization, inflammatory biomarkers and psychotic phenomena in adolescence: A longitudinal cohort study

Exposure to victimization in childhood has been linked to the development of psychosis. However, little is known about how childhood victimization is translated into biological risk for psychosis. One possibility is via increased inflammation. This study aimed to investigate the association between childhood victimization, psychotic experiences (PEs) in adolescence and inflammatory markers using data from a general population cohort. Participants were 1,419 British-born children followed from birth to age 18 years as part of the Environmental Risk Longitudinal Twin Study. Childhood victimization was measured prospectively using multiple sources from birth to age 12 years. PEs were assessed during private interviews with participants at age 18 years for the period since age 12. Plasma C-reactive protein (CRP), interleukin-6 (IL-6), and soluble urokinase plasminogen activator receptor (suPAR) levels were measured from plasma samples collected from participants at 18 years. Young people with both PEs and childhood victimization were more likely to belong to a group with elevated suPAR, CRP and IL-6 levels at 18 years of age (OR = 3.34, 95% CI 1.69-6.59, p = 0.001) than those with no childhood victimization and without PEs. However, this association was attenuated when adjusted for other risk factors for elevated inflammation at age 18 (OR = 1.94, 95% CI 0.94-4.04, p = 0.075). In contrast, presence of PEs without childhood victimization was not significantly associated with age-18 inflammatory markers and neither was childhood victimization without PEs (all p's greater than 0.05). The current study highlights that inflammatory dysregulation is mostly present in adolescents reporting PEs who also experienced childhood victimization, though this seemed to be largely due to concurrent inflammation-related risk factors.

The Predictive Value of Soluble Urokinase-Type Plasminogen Activator Receptor in Contrast-Induced Acute Kidney Injury in Patients Undergoing Percutaneous Coronary Intervention

Objective

Soluble urokinase-type plasminogen activator receptor (SuPAR) is a circulating protein and a novel identified promising biomarker for various renal diseases and kidney injury. However, it remains unknown on the predictive value of suPAR in contrast induced acute kidney injury (CI-AKI) in patients undergoing percutaneous coronary intervention (PCI).

Methods

A total of 399 patients undergoing PCI were enrolled in the research from June 2020 to June 2021 in Zhongda Hospital. Patients were divided into CI-AKI and non-CI-AKI groups according to the preoperative and postoperative serum creatinine levels. Plasma suPAR level was detected through enzyme-linked immunosorbent assay on admission. Demographic data, hematological parameters, coronary angiography data and medications were recorded and compared between CI-AKI and non-CI-AKI groups. Logistic regression analysis and receiver operator characteristic (ROC) curve analysis were performed for identifying the independent risk factors of CI-AKI and assessment of the predictive value of suPAR for CI-AKI.

Results

CI-AKI occurred in 65 (16.3%) patients undergoing PCI. The level of suPAR in CI-AKI group was significantly higher than that in the non-CI-AKI group. Multivariate logistic regression indicated diabetes, lower LVEF, lower hydration rate, lower baseline eGFR, higher plasma suPAR (OR = 2.875, 95% CI = 2.038–3.672, P < 0.001) and volume of contrast media were all independent risk factors for CI-AKI after adjustment of the confounding factors. ROC analysis illustrated that the optimal area under the curve was 0.765, indicating plasma suPAR was a splendid predictor for CI-AKI. The corresponding cut-off value was 3.305 ng/mL, and the sensitivity and specificity were 63.1% and 82.3%, respectively.

Conclusion

Increased suPAR level is independently associated with elevated risk of suffering CI-AKI, and suPAR is a strong predictor for CI-AKI in patients undergoing PCI. SuPAR might act as a novel biomarker for CI-AKI in clinical practice.

Linking stressful life events and chronic inflammation using suPAR (soluble urokinase plasminogen activator receptor)

Stressful life events have been linked to declining health, and inflammation has been proposed as a physiological mechanism that might explain this association. Using 828 participants from the Dunedin Longitudinal Study, we tested whether people who experienced more stressful life events during adulthood would show elevated systemic inflammation when followed up in midlife, at age 45. We studied three inflammatory biomarkers: C-reactive protein (CRP), interleukin-6 (IL-6), and a newer biomarker, soluble urokinase plasminogen activator receptor (suPAR), which is thought to index systemic chronic inflammation. Stressful life events were not associated with CRP or IL-6. However, people who experienced more stressful life events from age 38 to 44 had elevated suPAR at age 45, and had significantly greater increases in suPAR from baseline to follow-up across the same period. When examining stressful life events across the lifespan, both adverse childhood experiences (ACEs) and adult stressful life events were independently associated with suPAR at age 45. ACEs moderated the association of adult stressful life events and suPAR at age 45-children with more ACEs showed higher suPAR levels after experiencing stressful life events as adults. The results suggest systemic chronic inflammation is one physiological mechanism that could link stressful life events and health, and support the use of suPAR as a useful biomarker for such research.

The levels of soluble urokinase plasminogen activator receptor (suPAR) in saliva are influenced by acute stress

Although elevations in systemic suPAR levels have been associated with inflammatory conditions and with exposure to life stress and adversity, it is not yet clear whether acute psychological stress influences suPAR levels, either systemically and/or in saliva. The aim of this study was to investigate whether salivary suPAR levels are increased following exposure to acute psychological stress. Healthy subjects, aged 18-40 years, completed a laboratory psychological stressor and provided saliva samples before and after the stress test (60 min apart). Levels of suPAR as well as those of cytokines increased in the post-stress samples (all ps < .001). Baseline and post-stress IL-1β and TNF-α as well as post-stress IL-6 correlated significantly with suPAR (all ps < .01), but IL-10 and baseline IL-6 did not. These results show that suPAR levels in saliva are stress-reactive and suggest a potential application as stress biomarkers in saliva, particularly given the advantage of easily detectable concentrations.

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.

Soluble Urokinase Plasminogen Activator Receptor as a Decision Marker for Early Discharge of Patients with COVID-19 Symptoms in the Emergency Department

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (The Covid-19 pandemic) strains health care capacity. Better risk stratification, with discharge of patients with a predicted mild disease trajectory, can ease this burden. Elevated blood-soluble urokinase plasminogen activator receptor (suPAR) has previously been shown to be associated with risk of intubation in confirmed COVID-19 patients.

OBJECTIVE

To evaluate whether point-of-care measures of suPAR in patients presenting to the emergency department (ED) with symptoms of COVID-19 can identify patients that can be safely discharged.

METHODS

Observational cohort study including all patients in the ED with symptoms of COVID-19 from March 19 to April 3, 2020. SuPAR was measured at first presentation. Review of electronic patient records 14 days after admission was used to assess disease trajectory. Primary endpoints were mild, moderate, severe, or very severe trajectory. The predictive value of suPAR, National Early Warning Score (NEWS), C-reactive protein (CRP), and duration of symptoms was calculated using receiver operating characteristics (ROC).

RESULTS

Of 386 patients, 171 (44%) had a mild disease trajectory, 79 (20%) a moderate, 63 (16%) a severe, and 73 (19%) a very severe disease trajectory. Low suPAR was a strong marker of mild disease trajectory. Results suggest a cut-off for discharge for suPAR < 2.0 ng/mL if suPAR is used as a single parameter, and <3.0 ng/mL when combined with NEWS ≤ 4 and CRP < 10 mg/L.

CONCLUSION

suPAR is a potential biomarker for triage and safe early discharge of patients with COVID-19 symptoms in the ED. suPAR can be used even before SARS-CoV-2 status is known.

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.

Time-resolved proteomic profiling of cigarette smoke-induced experimental chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is the third leading cause of illness and death worldwide. Current treatments aim to control symptoms with none able to reverse disease or stop its progression. We explored the major molecular changes in COPD pathogenesis.

METHODS

We employed quantitative label-based proteomics to map the changes in the lung tissue proteome of cigarette smoke-induced experimental COPD that is induced over 8 weeks and progresses over 12 weeks.

RESULTS

Quantification of 7324 proteins enabled the tracking of changes to the proteome. Alterations in protein expression profiles occurred in the induction phase, with 18 and 16 protein changes at 4- and 6-week time points, compared to age-matched controls, respectively. Strikingly, 269 proteins had altered expression after 8 weeks when the hallmark pathological features of human COPD emerge, but this dropped to 27 changes at 12 weeks with disease progression. Differentially expressed proteins were validated using other mouse and human COPD bronchial biopsy samples. Major changes in RNA biosynthesis (heterogeneous nuclear ribonucleoproteins C1/C2 [HNRNPC] and RNA-binding protein Musashi homologue 2 [MSI2]) and modulators of inflammatory responses (S100A1) were notable. Mitochondrial dysfunction and changes in oxidative stress proteins also occurred.

CONCLUSION

We provide a detailed proteomic profile, identifying proteins associated with the pathogenesis and disease progression of COPD establishing a platform to develop effective new treatment strategies.

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.

Admission levels of Soluble Urokinase Plasminogen Activator Receptor (suPAR) are Associated with the Development of Severe Complications in Hospitalised COVID-19 Patients: A Prospective Cohort Study

Objective

To examine the association between plasma levels of the soluble urokinase plasminogen activator receptor (suPAR) and the incidence of severe complications of COVID-19.

Methods

403 RT-PCR-confirmed COVID-19 patients were recruited and prospectively followed-up at a major hospital in the United Arab Emirates. The primary endpoint was time from admission until the development of a composite outcome, including acute respiratory distress syndrome (ARDS), intensive care unit (ICU) admission, or death from any cause. Patients discharged alive were considered as competing events to the primary outcome. Competing risk regression was used to quantify the association between suPAR and the incidence of the primary outcome.

Results

6.2% of patients experienced ARDS or ICU admission, but none died. Taking into account competing risk, the incidence of the primary outcome was 11.5% (95% confidence interval [CI], 6.7–16.3) in patients with suPAR levels >3.91 ng/mL compared to 2.9% (95% CI, 0.4–5.5) in those with suPAR ≤3.91 ng/mL. Also, an increase by 1 ng/mL in baseline suPAR resulted in a 58% rise in the hazard of developing the primary outcome (hazard ratio 1.6, 95% CI, 1.2–2.1, p = 0.003).

Conclusion

suPAR has an excellent prognostic utility in predicting severe complications in hospitalised COVID-19 patients.

Prognostic value of suPAR and hsCRP on acute kidney injury after cardiac surgery

Background

Acute kidney injury (AKI) represents a serious complication following cardiac surgery. Adverse outcome after cardiac surgery has been observed in the presence of elevated levels of soluble urokinase-type plasminogen activator receptor (suPAR) and high-sensitivity C-Reactive Protein (hsCRP). The aim of study was (i) to investigate the relationship between preoperative elevated levels of suPAR and hsCRP and postoperative AKI in unselected cardiac surgery patients and (ii) to assess whether the concentration of the biomarkers reflected severity of AKI.

Methods

In a retrospective observational study, biobank blood plasma samples (n = 924) from patients admitted for elective on-pump cardiac surgery were analysed for suPAR and hsCRP levels. The relation between suPAR and hsCRP-values and AKI (any stage), defined by the KDIGO (Kidney Disease: Improving Global Outcomes) criteria, was assessed using adjusted logistic regression. Further, the association between biomarkers and severity (KDIGO 1, KDIGO 2–3 and renal replacement therapy (RRT)) was assessed using adjusted logistic regression.

Results

Postoperative AKI (any stage) was observed in 327 patients (35.4 %). A doubling of preoperative suPAR corresponded to an adjusted odds ratio (OR) for postoperative AKI (any stage) of 1.62 (95 % CI 1.26–2.09, p < 0.001). Furthermore, a doubling of suPAR had an adjusted OR of 1.50 (95 % CI 1.16–1.93, p = 0.002), 2.44 (95 % CI 1.56–3.82, p < 0.001) and 1.92 (95 % CI 1.15–3.23, p = 0.002), for KDIGO 1, KDIGO 2–3 and need for RRT, respectively. No significant association was found between elevated levels of hsCRP and any degree of AKI.

Conclusions

Increasing levels of suPAR, but not hsCRP, were associated with development and severity of AKI following on-pump cardiac surgery.

The Expanding Role of Biomarkers in Diagnosing Infection in Total Joint Arthroplasty: A Review of Current Literature

Consistent diagnosis of periprosthetic infection in total joint arthroplasty continues to elude the orthopedic surgeon because no gold standard test exists. Therefore clinicians must rely on a combination of tests to help aid the diagnosis. The expanding role of biomarkers has shown promising results to more accurately diagnose an infection when combined with clinical suspicion and bacterial culture testing. This paper reviews the diagnostic capabilities of the most current serum and synovial biomarkers as well as next generation sequencing in the setting of periprosthetic joint infection. Future research and high-powered studies will be necessary to determine sensitivity and specificity of each biomarker.

Blood biomarker discovery for autism spectrum disorder: A proteomic analysis

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and social interaction and restricted, repetitive patterns of behavior, interests, or activities. Given the lack of specific pharmacological therapy for ASD and the clinical heterogeneity of the disorder, current biomarker research efforts are geared mainly toward identifying markers for determining ASD risk or for assisting with a diagnosis. A wide range of putative biological markers for ASD is currently being investigated. Proteomic analyses indicate that the levels of many proteins in plasma/serum are altered in ASD, suggesting that a panel of proteins may provide a blood biomarker for ASD. Serum samples from 76 boys with ASD and 78 typically developing (TD) boys, 18 months-8 years of age, were analyzed to identify possible early biological markers for ASD. Proteomic analysis of serum was performed using SomaLogic’s SOMAScan^TM assay 1.3K platform. A total of 1,125 proteins were analyzed. There were 86 downregulated proteins and 52 upregulated proteins in ASD (FDR < 0.05). Combining three different algorithms, we found a panel of 9 proteins that identified ASD with an area under the curve (AUC) = 0.8599±0.0640, with specificity and sensitivity of 0.8217±0.1178 and 0.835±0.1176, respectively. All 9 proteins were significantly different in ASD compared with TD boys, and were significantly correlated with ASD severity as measured by ADOS total scores. Using machine learning methods, a panel of serum proteins was identified that may be useful as a blood biomarker for ASD in boys. Further verification of the protein biomarker panel with independent test sets is warranted.

PEGylated Serp-1 Markedly Reduces Pristane-Induced Experimental Diffuse Alveolar Hemorrhage, Altering uPAR Distribution, and Macrophage Invasion

Diffuse alveolar hemorrhage (DAH) is one of the most serious clinical complications of systemic lupus erythematosus (SLE). The prevalence of DAH is reported to range from 1 to 5%, but while DAH is considered a rare complication there is a reported 50-80% mortality. There is at present no proven effective treatment for DAH and the therapeutics that have been tested have significant side effects. There is a clear necessity to discover new drugs to improve outcomes in DAH. Serine protease inhibitors, serpins, regulate thrombotic and thrombolytic protease cascades. We are investigating a Myxomavirus derived immune modulating serpin, Serp-1, as a new class of immune modulating therapeutics for vasculopathy and lung hemorrhage. Serp-1 has proven efficacy in models of herpes virus-induced arterial inflammation (vasculitis) and lung hemorrhage and has also proved safe in a clinical trial in patients with unstable coronary syndromes and stent implant. Here, we examine Serp-1, both as a native secreted protein expressed by CHO cells and as a polyethylene glycol modified (PEGylated) variant (Serp-1m5), for potential therapy in DAH. DAH was induced by intraperitoneal (IP) injection of pristane in C57BL/6J (B6) mice. Mice were treated with 100 ng/g bodyweight of either Serp-1 as native 55 kDa secreted glycoprotein, or as Serp-1m5, or saline controls after inducing DAH. Treatments were repeated daily for 14 days (6 mice/group). Serp-1 partially and Serp-1m5 significantly reduced pristane-induced DAH when compared with saline as assessed by gross pathology and H&E staining (Serp-1, p = 0.2172; Serp-1m5, p = 0.0252). Both Serp-1m5 and Serp-1 treatment reduced perivascular inflammation and reduced M1 macrophage (Serp-1, p = 0.0350; Serp-1m5, p = 0.0053), hemosiderin-laden macrophage (Serp-1, p = 0.0370; Serp-1m5, p = 0.0424) invasion, and complement C5b/9 staining. Extracellular urokinase-type plasminogen activator receptor positive (uPAR+) clusters were significantly reduced (Serp-1, p = 0.0172; Serp-1m5, p = 0.0025). Serp-1m5 also increased intact uPAR+ alveoli in the lung (p = 0.0091). In conclusion, Serp-1m5 significantly reduces lung damage and hemorrhage in a pristane model of SLE DAH, providing a new potential therapeutic approach.

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.

The use of soluble urokinase plasminogen activator receptor (suPAR) as a marker of sepsis in the emergency department setting. A current review

Aim: The purpose of this review is to summarize all relevant publications regarding the use and validity of the soluble urokinase plasminogen activator receptor (suPAR) when used by clinicians in the emergency department (ED) for the detection and monitoring of patients with sepsis syndrome. Methods: A PubMed search was conducted in order to identify all publications related to the use of suPAR in sepsis patients in the ED setting. Results: Although suPAR is actively involved in the pathophysiology of sepsis, over the last 15 years, only a few studies have been published referring to its predictive validity in the ED. Conclusions: SuPAR can be easily and rapidly measured in an ED setting, and its role in the exclusion of an infection and the management of sepsis, alone or in combination to other biomarkers, should be further evaluated. The optimal cut-off value, the timing of the measurement and the role of the suPAR in an ED setting should be further investigated.

Development of inhibitors for uPAR: blocking the interaction of uPAR with its partners

Urokinase-type plasminogen activator receptor (uPAR) mediates a multitude of biological activities, has key roles in several clinical indications, including malignancies and inflammation, and, thus, has attracted intensive research over the past few decades. The pleiotropic functions of uPAR can be attributed to its interaction with an array of partners. Many inhibitors have been developed to intervene with the interaction of uPAR with these partners. Here, we review the development of these classes of uPAR inhibitor and their inhibitory mechanisms to promote the translation of these inhibitors to clinical applications.

Prognostic Value of Soluble Urokinase-Type Plasminogen Activator Receptor and High-Sensitivity C-Reactive Protein on Postoperative Mortality in Patients Undergoing Elective On-Pump Cardiac Surgery

OBJECTIVES

Elevated soluble urokinase-type plasminogen activator receptor (suPAR) and high-sensitivity C-reactive protein (hsCRP) have been associated with increased mortality in patients with cardiovascular disease. The aim of the present study was to explore the relationship between suPAR and hsCRP values and associated mortality after elective cardiac surgery. A secondary aim was to assess whether a combined risk model of European System for Cardiac Operative Risk Evaluation (EuroSCORE II), suPAR, and/or hsCRP would improve the prognostic accuracy compared with EuroSCORE II alone.

DESIGN

Retrospective observational study.

SETTING

Single-center, university hospital.

PARTICIPANTS

Adult patients admitted for elective on-pump cardiac surgery were included. Biobank blood samples were obtained from previous research projects at a tertiary heart center from 2012 to 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 931 patients were included. Kaplan-Meier and Cox proportional hazard analyses were used to explore a potential association between preoperative suPAR and hsCRP values and all-cause mortality up to one year after surgery. Thirty-day mortality was predicted from suPAR, hsCRP, and EuroSCORE II by logistic regression and compared using area under the receiver operating characteristics curve and Brier scores. After adjustment for known confounders, a doubling of suPAR and hsCRP corresponded to a hazard ratio for all-cause mortality of 2.27 (95% confidence interval 1.65-3.11; p < 0.001) and 1.26 (95% confidence interval 1.07-1.49; p = 0.005), respectively. However, adding the biomarkers to EuroSCORE II did not improve prediction/discrimination with respect to 30-day mortality.

CONCLUSIONS

Elevated preoperative levels of suPAR and hsCRP were associated with all-cause mortality in elective cardiac surgery patients. However, inclusion of biomarkers did not improve the prognostic accuracy of EuroSCORE II.

SuPAR, a potential inflammatory mediator in psoriasis pathogenesis

Psoriasis is an inflammatory skin disorder that is strongly associated with the metabolic syndrome. The sole reliance on clinical examination to guide prognostication and treatment is insufficient at best; accurate diagnostic and prognostic psoriatic molecular biomarkers are needed. Soluble urokinase plasminogen activator receptor (suPAR) has been implicated in inflammation. The aim of this study is to determine whether suPAR plays a role in the pathogenesis of psoriasis and whether an association exists between suPAR levels, disease severity, and other variables like insulin, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). This study also compares the pattern of uPAR staining in healthy vs psoriatic skin: 39 psoriatic and 30 control subjects were included. Two biopsies (affected and unaffected skin) and one biopsy were taken from psoriasis patients and healthy controls, respectively, with uPAR staining of all skin biopsies. Blood samples from all subjects were obtained to determine suPAR, ESR, CRP, and fasting insulin levels. uPAR staining was prominent in unaffected skin from psoriasis patients and healthy individuals vs weak/absent uPAR staining in psoriatic skin. CRP, ESR and suPAR levels were not significantly elevated in the mild psoriasis group compared to healthy controls. The loss of epidermal uPAR is suggestive of its tentative role in the pathogenesis of psoriasis. Patients with mild-moderate psoriasis possibly lack the powerful association attributed to metabolic syndrome in psoriatic patients. Further studies on larger cohorts are needed to ascertain the validity of the mentioned conclusions.

Plasma marker for systemic inflammation is increased in Mexican Tarahumara following ultra-distance running

OBJECTIVES

Previous studies have suggested that acute exercise-induced cardiac and kidney damage following ultra-distance running is low in Mexican Tarahumara even though C-reactive protein (CRP) remained elevated 24 hours post-race. We aimed to study if the plasma biomarker, soluble urokinase-type plasminogen activator receptor (suPAR), could replace or complement CRP as a systemic inflammation biomarker in Tarahumara men and women following ultra-distance running.

METHODS

Plasma samples were collected pre-race and at three to six different time points post-race in Mexican Tarahumara competing in three independent ultramarathons; men running 78 km (GroupI, n = 9), women running 52 km (GroupII, n = 3), and men running 63 km (GroupIII, n = 10). Baseline anthropometry, blood pressure, glycated hemoglobin, and hemoglobin were measured, aerobic fitness was estimated by submaximal step test, absolute and relative running intensity assessed using combined heart rate and accelerometry. Plasma was collected pre- and post-race to analyze concentrations of suPAR, and-for women only-a panel of inflammatory, cardiac and kidney plasma biomarkers. Mixed-effect models were used to evaluate the effect of ultramarathon running on plasma suPAR concentrations.

RESULTS

Compared to pre-race values, suPAR was significantly elevated in plasma <5 minutes after the three ultramarathon races (70%-109% increase of the mean for the three groups). Furthermore, plasma suPAR remained significantly elevated up to 6 hours post-race for all three groups of runners independent of running intensity.

CONCLUSIONS

The results suggest that suPAR can complement, but not replace CRP following ultra-distance running in Tarahumara men and women.

Challenges in primary focal segmental glomerulosclerosis diagnosis: from the diagnostic algorithm to novel biomarkers

Primary or idiopathic focal segmental glomerulosclerosis (FSGS) is a kidney entity that involves the podocytes, leading to heavy proteinuria and in many cases progresses to end-stage renal disease. Idiopathic FSGS has a bad prognosis, as it involves young individuals who, in a considerably high proportion (∼15%), are resistant to corticosteroids and other immunosuppressive treatments as well. Moreover, the disease recurs in 30–50% of patients after kidney transplantation, leading to graft function impairment. It is suspected that this relapsing disease is caused by a circulating factor(s) that would permeabilize the glomerular filtration barrier. However, the exact pathologic mechanism is an unsettled issue. Besides its poor outcome, a major concern of primary FSGS is the complexity to confirm the diagnosis, as it can be confused with other variants or secondary forms of FSGS and also with other glomerular diseases, such as minimal change disease. New efforts to optimize the diagnostic approach are arising to improve knowledge in well-defined primary FSGS cohorts of patients. Follow-up of properly classified primary FSGS patients will allow risk stratification for predicting the response to different treatments. In this review we will focus on the diagnostic algorithm used in idiopathic FSGS both in native kidneys and in disease recurrence after kidney transplantation. We will emphasize those potential confusing factors as well as their detection and prevention. In addition, we will also provide an overview of ongoing studies that recruit large cohorts of glomerulopathy patients (Nephrotic Syndrome Study Network and Cure Glomerulonephropathy, among others) and the experimental studies performed to find novel reliable biomarkers to detect primary FSGS.

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.

Computational Analysis of the Global Effects of Ly6E in the Immune Response to Coronavirus Infection Using Gene Networks

Gene networks have arisen as a promising tool in the comprehensive modeling and analysis of complex diseases. Particularly in viral infections, the understanding of the host-pathogen mechanisms, and the immune response to these, is considered a major goal for the rational design of appropriate therapies. For this reason, the use of gene networks may well encourage therapy-associated research in the context of the coronavirus pandemic, orchestrating experimental scrutiny and reducing costs. In this work, gene co-expression networks were reconstructed from RNA-Seq expression data with the aim of analyzing the time-resolved effects of gene Ly6E in the immune response against the coronavirus responsible for murine hepatitis (MHV). Through the integration of differential expression analyses and reconstructed networks exploration, significant differences in the immune response to virus were observed in Ly6E Δ H S C compared to wild type animals. Results show that Ly6E ablation at hematopoietic stem cells (HSCs) leads to a progressive impaired immune response in both liver and spleen. Specifically, depletion of the normal leukocyte mediated immunity and chemokine signaling is observed in the liver of Ly6E Δ H S C mice. On the other hand, the immune response in the spleen, which seemed to be mediated by an intense chromatin activity in the normal situation, is replaced by ECM remodeling in Ly6E Δ H S C mice. These findings, which require further experimental characterization, could be extrapolated to other coronaviruses and motivate the efforts towards novel antiviral approaches.

Soluble urokinase plasminogen activator receptor (suPAR) as a prognostic marker of mortality in healthy, general and patient populations: protocol for a systematic review and meta-analysis

INTRODUCTION

Chronic inflammation is increasingly recognised as a major contributor to disease, disability and ultimately death, but measuring the levels of chronic inflammation remains non-canonised, making it difficult to relate chronic inflammation and mortality. Soluble urokinase plasminogen activator receptor (suPAR), an emerging biomarker of chronic inflammation, has been proposed as a prognostic biomarker associated with future incidence of chronic disease and mortality in general as well as patient populations. Proper prognostic biomarkers are important as they can help improve risk stratification in clinical settings and provide guidance in treatment or lifestyle decisions as well as in the design of randomised trials. Here, we wish to summarise the evidence about the overall association of the biomarker suPAR with mortality in healthy, general and patient populations across diseases.

METHODS AND ANALYSIS

The search will be conducted using Medline, Embase and Scopus databases from their inception to 03 June 2020 to identify studies investigating 'suPAR' and 'mortality'. Observational studies and control groups from intervention studies written in English or Danish will be included. The 'Quality In Prognosis Studies' tool will be used to assess the risk of bias for the studies included. Unadjusted and adjusted mortality outcome measures (eg, risk ratios, ORs, HRs) with 95% CIs will be extracted for healthy individuals, general and patient populations. The primary outcome is all-cause mortality within any given follow-up. Subgroup analyses will be performed based on time of outcome, cause of death, population type, adjustments for conventional risk factors and inflammation markers.

ETHICS AND DISSEMINATION

This systematic review will synthesise evidence on the use of suPAR as a prognostic marker for mortality. The results will be disseminated by publication in a peer-reviewed journal. Data used will be obtained from published studies, and ethics approval is therefore not necessary for this systematic review.

TRIAL REGISTRATION NUMBER PROSPERO

CRD42020167401.

Validation of suPAR turbidimetric assay on Cobas® (c502 and c702) and comparison to suPAR ELISA

suPAR is a plasma marker of chronic inflammation, and an elevated suPAR is consistently associated with worse outcome in a variety of clinical conditions. Quantification of suPAR is useful for determining patient risk in triage, but there is no fast automatized method for quick determination of suPAR. We developed and validated a rapid latex particle-enhanced turbidimetric immunoassay for quantification of plasma suPAR on the c502 and the c702 Roche Cobas® 8000 measurment systems. The turbidimetric assay was validated against the suPARnostic® ELISA (ViroGates, Denmark). This validation demonstrates suPAR can be analysed by turbidimetry giving very similar results (<15% difference) compared to the ELISA method and the observed correlations (n = 103) were strong, r > 0.95. Roche Cobas® 8000 instruments demonstrated repeatability and repoducibility, CV % at 3.4-4.1 and 5.7-11.4, respectively. The estimated limit of detection was 1.30 µg/L and 1.31 µg/L for the Cobas® c502 and c702, respectively. Dilution tests showed linearity of suPAR from 1.8 to 26.5 μg/L. The acceptable concentrations of Bilirubin, Intralipid and Hemoglobin, were 350 µmol/L, 3.3 g/L and 1.4 g/L, respectively. suPAR can be quantified reproducibly within 10 min using a turbidimetry assay. This assay is faster than ELISA with similar results, making it suitable for clinical routine analysis.