Circulating Soluble Urokinase Plasminogen Activator Receptor as a Predictive Indicator for COVID-19-Associated Acute Kidney Injury and Mortality: Clinical and Bioinformatics Analysis.

Urokinase receptors regulate the interplay between inflammation, immunity, and blood clotting. The soluble urokinase plasminogen activator system is an immunologic regulator affecting endothelial function and its related receptor; the soluble urokinase plasminogen activator receptor (suPAR) has been reported to impact kidney injury. This work aims to measure serum levels of suPAR in COVID-19 patients and correlate the measurements with variable clinicolaboratory parameters and patient outcomes. In this prospective cohort study, 150 COVID-19 patients and 50 controls were included. The circulating suPAR levels were quantified by Enzyme-linked immunosorbent assay (ELISA). Routine COVID-19 laboratory assessments, including CBC, CRP, LDH, serum creatinine, and estimated glomerular filtration rates, were performed. The need for oxygen therapy, CO-RAD score, and survival rates was assessed. Bioinformatic analysis and molecular docking were run to explore the urokinase receptor structure/function and to characterize molecules as potential anti-suPAR therapeutic targets, respectively. We found higher circulating suPAR levels in COVID-19 patients vs. controls (p < 0.001). Circulating suPAR levels positively correlated with COVID-19 severity, the need for O2 therapy, the total leukocytes count, and the neutrophils to lymphocyte ratio, while they were negatively correlated with the O2 saturation level, albumin, blood calcium, lymphocytic count, and GFR. In addition, the suPAR levels were associated with poor prognostic outcomes such as a high incidence of acute kidney injury (AKI) and mortality rate. Kaplan-Meier curves showed a lower survival rate with higher suPAR levels. The logistic regression analysis confirmed the significant association of suPAR levels with the occurrence of AKI related to COVID-19 and with increased mortality probability within three months of COVID-19 follow-up. Some compounds that can act similarly to uPAR were discovered and tested by molecular docking to identify the possible ligand-protein interactions. In conclusion, higher circulating suPAR levels were associated with COVID-19 severity and could be considered a putative predictor of AKI development and mortality.

Prediction value of soluble urokinase plasminogen activator receptor (suPAR) in COVID-19 patients - a systematic review and meta-analysis.

INTRODUCTION AND OBJECTIVE: In COVID-19, the rapid prediction of the severity of a patient's condition using modern biomarkers can accelerate the implementation of appropriate therapy, and thus improve the patient's prognosis. MATERIAL AND METHODS: A meta-analysis was conducted of data available in the literature on the differences in baseline suPAR blood concentration between patients (1) who tested positive and negative for COVID-19, (2) who had severe and non-severe COVID-19, and (3) COVID-19 survivors and non-survivors. RESULTS: SuPAR levels in SARS-CoV-2 negative and positive patients varied and amounted to 3.61±1.59 ng/ml vs. 6.45±3.13 ng/ml, respectively (MD = -3.18; 95%CI: -4.71 to -1.66; p<0.001). suPAR levels among non-severe and severe COVID-19 patients were 7.06±2.64 ng/ml and 5.06±3.16 ng/ml (MD = 0.18; 95%CI: -2.48 to 2.83; p=0.90), respectively. Pooled analysis showed that suPAR levels between severe versus critical COVID-19 patients to be 5.59±1.54 ng/ml and 6.49±1.43 ng/ml, respectively (MD = -1.00; 95%CI: -1.31 to -0.70; p<0.001). The suPAR levels between ICU survivors versus non-survivors amounted to 5.82±2.33 ng/ml and 8.43±4.66 ng/ml (MD = -3.59; 95%CI: -6.19 to -1.00; p=0.007). In the case of in-hospital mortality, the mean suPAR level among survivors to hospital discharge was 5.63±1.27 ng/ml, compared to 7.85±2.61 ng/ml for patients who did not survive (MD = -3.58; 95%CI: -5.42 to -1.74; p<0.001). CONCLUSIONS: SuPAR levels are significantly elevated in severe COVID-19 illness and maybe useful in predicting mortality. Further studies are needed to determine cut-off points and clarify the association of suPAR levels with disease progression. This is of utmost importance given the ongoing pandemic and overburdened health care systems.

Anakinra in hospitalized COVID-19 patients guided by baseline soluble urokinase plasminogen receptor plasma levels: A real world, retrospective cohort study.

BACKGROUND: In patients with COVID-19 and baseline soluble urokinase plasminogen receptor plasma (suPAR) levels ≥ 6ng/mL, early administration of anakinra, a recombinant interleukin-1 receptor antagonist, may prevent disease progression and death. In case of suPAR testing unavailability, the Severe COvid Prediction Estimate (SCOPE) score may be used as an alternative in guiding treatment decisions. METHODS: We conducted a monocenter, retrospective cohort study, including patients with SARS-CoV2 infection and respiratory failure. Patients treated with anakinra (anakinra group, AG) were compared to two control groups of patients who did not receive anakinra, respectively with ≥ 6 ng/mL (CG1) and < 6 ng/mL (CG2) baseline suPAR levels. Controls were manually paired by age, sex, date of admission and vaccination status and, for patients with high baseline suPAR, propensity score weighting for receiving anakinra was applied. Primary endpoint of the study was disease progression at day 14 from admission, as defined by patient distribution on a simplified version of the 11-point World Health Organization Clinical Progression Scale (WHO-CPS). RESULTS: Between July, 2021 and January, 2022, 153 patients were included, among which 56 were treated with off-label anakinra, 49 retrospectively fulfilled prescriptive criteria for anakinra and were assigned to CG1, and 48 presented with suPAR levels < 6ng/mL and were assigned to CG2. At day 14, when comparing to CG1, patients who received anakinra had significantly reduced odds of progressing towards worse clinical outcome both in ordinal regression analysis (OR 0.25, 95% CI 0.11-0.54, p<0.001) and in propensity-adjusted multiple logistic regression analysis (OR 0.32, 95% CI 0.12-0.82, p = 0.021) thus controlling for a wide number of covariates. Sensitivities of baseline suPAR and SCOPE score in predicting progression towards severe disease or death at day 14 were similar (83% vs 100%, p = 0.59). CONCLUSION: This real-word, retrospective cohort study confirmed the safety and the efficacy of suPAR-guided, early use of anakinra in hospitalized COVID-19 patients with respiratory failure.

The Perspective of Vitamin D on suPAR-Related AKI in COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic has claimed the lives of millions of people around the world. Severe vitamin D deficiency can increase the risk of death in people with COVID-19. There is growing evidence that acute kidney injury (AKI) is common in COVID-19 patients and is associated with poorer clinical outcomes. The kidney effects of SARS-CoV-2 are directly mediated by angiotensin 2-converting enzyme (ACE2) receptors. AKI is also caused by indirect causes such as the hypercoagulable state and microvascular thrombosis. The increased release of soluble urokinase-type plasminogen activator receptor (suPAR) from immature myeloid cells reduces plasminogen activation by the competitive inhibition of urokinase-type plasminogen activator, which results in low plasmin levels and a fibrinolytic state in COVID-19. Frequent hypercoagulability in critically ill patients with COVID-19 may exacerbate the severity of thrombosis. Versican expression in proximal tubular cells leads to the proliferation of interstitial fibroblasts through the C3a and suPAR pathways. Vitamin D attenuates the local expression of podocyte uPAR and decreases elevated circulating suPAR levels caused by systemic inflammation. This decrease preserves the function and structure of the glomerular barrier, thereby maintaining renal function. The attenuated hyperinflammatory state reduces complement activation, resulting in lower serum C3a levels. Vitamin D can also protect against COVID-19 by modulating innate and adaptive immunity, increasing ACE2 expression, and inhibiting the renin-angiotensin-aldosterone system. We hypothesized that by reducing suPAR levels, appropriate vitamin D supplementation could prevent the progression and reduce the severity of AKI in COVID-19 patients, although the data available require further elucidation.

COMPARATIVE EVALUATION AND PROGNOSTIC UTILITY OF NEURONAL INJURY BIOMARKERS IN COVID-19 PATIENTS: A PROSPECTIVE STUDY.

ABSTRACT: Background : COVID-19 disease severity markers include mostly molecules related to not only tissue perfusion, inflammation, and thrombosis, but also biomarkers of neural injury. Clinical and basic research has demonstrated that SARS-COV-2 affects the central nervous system. The aims of the present study were to investigate the role of neural injury biomarkers and to compare them with inflammatory markers in their predictive ability of mortality. Methods : We conducted a prospective observational study in critically ill patients with COVID-19 and in a cohort of patients with moderate/severe disease. S100b, neuron-specific enolase (NSE), and inflammatory markers, including soluble urokinase plasminogen activator receptor (suPAR), were measured on intensive care unit or ward admission, respectively. Statistical comparisons between patient groups were performed for all biomarkers under investigation. Correlations between different biomarkers were tested with Spearman correlation coefficient. Receiver operating characteristic curves were plotted using mortality as the classification variable and the biomarker levels on admission as the prognostic variables. Results : A total of 70 patients with COVID-19 were included in the final analysis. Of all studied biomarkers, s100b had the best predictive ability for death in the intensive care unit, with an area under the curve of 0.73 (0.61-0.83), P = 0.0003. S100b levels correlated with NSE, interleukin (IL)-8, and IL-10 (0.27 < rs < 0.37, P < 0.05), and tended to correlate with suPAR ( rs = 0.26, P = 0.05), but not with the vasopressor dose ( P = 0.62). Conclusion : Among the investigated biomarkers, s100b demonstrated the best predictive ability for death in COVID-19 patients. The overall biomarker profile of the patients implies direct involvement of the nervous system by the novel coronavirus.

The Association of PLAUR Genotype and Soluble suPAR Serum Level with COVID-19-Related Lung Damage Severity.

Uncovering the risk factors for acute respiratory disease coronavirus 2019 (COVID-19) severity may help to provide a valuable tool for early patient stratification and proper treatment implementation, improving the patient outcome and lowering the burden on the healthcare system. Here we report the results of a single-center retrospective cohort study on 151 severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-infected symptomatic hospitalized adult patients. We assessed the association of several blood test measurements, soluble urokinase receptor (uPAR) serum level and specific single nucleotide polymorphisms of ACE (I/D), NOS3 (rs2070744, rs1799983), SERPINE1 (rs1799768), PLAU (rs2227564) and PLAUR (rs344781, rs2302524) genes, with the disease severity classified by the percentage of lung involvement on computerized tomography scans. Our findings reveal that the T/C genotype of PLAUR rs2302524 was independently associated with a less severe lung damage (odds ratio 0.258 [0.071-0.811]). Along with high C-reactive protein, fibrinogen and soluble uPAR serum levels turned out to be independently associated with more severe lung damage in COVID-19 patients. The identified factors may be further employed as predictors of a possibly severe COVID-19 clinical course.

Interferon gamma-induced protein 10 (IP-10) for the early prognosis of the risk for severe respiratory failure and death in COVID-19 pneumonia.

OBJECTIVES: Elevated concentrations of soluble urokinase plasminogen activator receptor (suPAR) predict progression to severe respiratory failure (SRF) or death among patients with COVID-19 pneumonia and guide early anakinra treatment. As suPAR testing may not be routinely available in every health-care setting, alternative biomarkers are needed. We investigated the performance of C-reactive protein (CRP), interferon gamma-induced protein-10 (IP-10) and TNF-related apoptosis-inducing ligand (TRAIL) for predicting SRF or death in COVID-19. METHODS: Two cohorts were studied; one discovery cohort with 534 patients from the SAVE-MORE clinical trial; and one validation cohort with 364 patients from the SAVE trial including also 145 comparators. CRP, IP-10 and TRAIL were measured by the MeMed Key® platform in order to select the biomarker with the best prognostic performance for the early prediction of progression into SRF or death. RESULTS: IP-10 had the best prognostic performance: baseline concentrations 2000 pg/ml or higher predicted equally well to suPAR (sensitivity 85.0 %; negative predictive value 96.6 %). Odds ratio for poor outcome among anakinra-treated participants of the SAVE-MORE trial was 0.35 compared to placebo when IP-10 was 2,000 pg/ml or more. IP-10 could divide different strata of severity for SRF/death by day 14 in the validation cohort. Anakinra treatment decreased this risk irrespective the IP-10 concentrations. CONCLUSIONS: IP-10 concentrations of 2,000 pg/ml or higher are a valid alternative to suPAR for the early prediction of progression into SRF or death the first 14 days from hospital admission for COVID-19 and they may guide anakinra treatment. CLINICALTRIALS: gov, NCT04680949 and NCT04357366.

Kinetics of SuPAR hemoadsorption in critical COVID-19 patients on renal replacement therapy.

BACKGROUND: SARS-CoV-2 viral infection is associated with a rapid and vigorous systemic inflammatory response syndrome. Soluble urokinase-type plasminogen activator receptor (suPAR) is a novel biomarker, both indicative of inflammation and propagating it. Hemoadsorption has been proposed as a potential therapy in COVID-19 patients, therefore the aim of this study is to determine suPAR kinetics during hemoadsoprtion. METHODS: This was a prospective observational study of critical COVID-19 patients, enrolled when hemoperfusion therapy was initiated. Hemoadsorber was integrated into the continuous renal replacement therapy circuit. The first series of suPAR measurements was performed 10 minutes after the start of the session, sampling both incoming and outgoing lines of the adsorber. A second series of the measurements was performed beforefinishing the session with the same adsorber. Statistical significance level was set < 0.05. RESULTS: This study included 18 patients. In the beginning of the session the fraction of suPAR cleared across the adsorber was 29.5% [16-41], and in the end of the session it decreased to 7.2% [4-22], 4 times lower, p = 0.003. The median length of session was 21 hours, with minimal duration of 16 hours and maximal duration of 24 hours. The median suPAR before the procedure was 8.71 [7.18-10.78] and after the session was 7.35 [6.53-11.28] ng/ml. There was no statistically significant difference in suPAR concentrations before and after the session (p = 0.831). CONCLUSIONS: This study concluded that in the beginning of the hemoadsorption procedure significant amount of suPAR is removed from the circulation. However, in the end of the procedure there is a substantial drop in adsorbed capacity. Furthermore, despite a substantial amount of suPAR cleared there is no significant difference in systemic suPAR concentrations before and after the hemoadsorption procedure.

[Evaluation of Serum Pentraxin-3 and suPAR Levels as Acute Phase Reactants in Patients with COVID-19]. / COVID-19 Tanili Hastalarda Akut Faz Reaktani Olarak Serum Pentraksin-3 ve suPAR Düzeylerinin Degerlendirilmesi.

Coronavirus disease-2019 (COVID-19) is the most challenging health problem of our century, but our knowledge about the disease is limited. Most individuals infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which causes COVID-19, have mild symptoms such as headache, sore throat, joint pain, loss of sense of taste and smell. However, infection also causes significant morbidity and mortality, especially in individuals over 65 years of age with comorbidities. However, it is not known exactly which patients will have a poor prognosis. In this study, it was aimed to determine serum Pentraxin-3 (PTX3) and soluble urokinase plasminogen activator receptor (suPAR) levels in COVID-19 patients, and to evaluate the relationship between PTX3 and suPAR levels and the clinical status of the disease. This study was conducted with 150 patients who were confirmed to have COVID-19 by microbiological or clinical/radiological methods between April 1 and December 31, 2020. Thirty people with no known history or symptoms of COVID-19 and negative reverse transcription-polymerase chain reaction (RT-PCR) results also constituted the control group. Patients admitted to inpatient services due to COVID-19 constituted the service group (n= 75) and patients admitted to the intensive care unit (ICU) constituted the ICU group (n= 75). Serum PTX3 and suPAR levels were analyzed by enzyme-linked immunoassay (ELISA) and the results were compared between the three groups. The patients' leukocyte, neutrophil, neutrophil/lymphocyte ratio (NLR), troponin, procalcitonin (PCT), D-dimer, C-reactive protein (CRP), lymphocyte and ferritin results were included in the analysis. The mean age of the patients was 67.2 ± 11.8, and 62.0 ± 8.4 in the control group. There was no significant difference between the groups in terms of female/male ratio (p= 0.582). The PTX3 and suPAR levels of the patients were higher than the controls (p= 0.001, p= 0.023, respectively). PTX3 and suPAR levels were higher in the service group than the ICU group (p<0.001, p= 0.004, respectively) and the control group (p<0.001, p= 0.001, respectively). However, PTX3 (p= 0.291) and suPAR (p= 0.411) concentrations did not differ between ICU and control groups. The most determining parameters in ICU admission were found to be leukocytes (AUC= 0.840), neutrophils (AUC= 0.840), and NLR (AUC= 0.835), respectively. The most predictive parameters for mortality were PCT (AUC= 0.712), NLR (AUC= 0.708) and D-dimer (AUC= 0.695), respectively. In our study, serum PTX3 and suPAR concentrations were found to be high in COVID-19 patients. In patients admitted to the ICU, PTX3 and suPAR levels were observed at low levels. Low levels of PTX3 and suPAR in COVID-19 patients were thought to be clinically important.

Soluble urokinase Plasminogen Activator Receptor (suPAR) levels are predictive of COVID-19 severity: an Italian experience.

BACKGROUND: The soluble urokinase Plasminogen Activator Receptor (suPAR) has been identified as a reliable marker of COVID-19 severity, helping in personalizing COVID-19 therapy. This study aims to evaluate the correlation between suPAR levels and COVID-19 severity, in relation to the traditional inflammatory markers. METHODS: Sera from 71 COVID-19 patients were tested for suPAR levels using Chorus suPAR assay (Diesse Diagnostica Senese SpA, Italy). suPAR levels were compared with other inflammatory markers: IL-1ß, IL-6, TNF-α, circulating calprotectin, neutrophil and lymphocyte counts, and Neutrophil/Lymphocytes Ratio (NLR). Respiratory failure, expressed as P/F ratio, and mortality rate were used as indicators of disease severity. RESULTS: A positive correlation of suPAR levels with IL-6 (r = 0.479, p = 0.000), TNF-α (r = 0.348, p = 0.003), circulating calprotectin (r = 0.369, p = 0.002), neutrophil counts (r = 0.447, p = 0.001), NLR (r = 0.492, p = 0.001) has been shown. Stratifying COVID-19 population by suPAR concentration above and below 6 ng/mL, we observed higher levels of circulating calprotectin (10.1 µg/mL, SD 7.9 versus 6.4 µg/mL, SD 7.5, p < 0.001), higher levels of P/F ratio (207.5 IQR 188.3 vs 312.0 IQR 127.8, p = 0.013) and higher mortality rate. Median levels of suPAR were increased in all COVID-19 patients requiring additional respiratory support (Nasal Cannula, Venturi Mask, BPAP and CPAP) (6.5 IQR = 4.9) compared to the group at room air (4.6 IQR = 4.2). CONCLUSION: suPAR levels correlate with disease severity and survival rate of COVID-19 patients, representing a promising prognostic biomarker for the risk assessment of the disease.

Soluble Urokinase Plasminogen Activator Receptor and Venous Thromboembolism in COVID-19.

Background Venous thromboembolism (VTE) contributes significantly to COVID-19 morbidity and mortality. The urokinase receptor system is involved in the regulation of coagulation. Levels of soluble urokinase plasminogen activator receptor (suPAR) reflect hyperinflammation and are strongly predictive of outcomes in COVID-19. Whether suPAR levels identify patients with COVID-19 at risk for VTE is unclear. Methods and Results We leveraged a multinational observational study of patients hospitalized for COVID-19 with suPAR and D-dimer levels measured on admission. In 1960 patients (mean age, 58 years; 57% men; 20% Black race), we assessed the association between suPAR and incident VTE (defined as pulmonary embolism or deep vein thrombosis) using logistic regression and Fine-Gray modeling, accounting for the competing risk of death. VTE occurred in 163 (8%) patients and was associated with higher suPAR and D-dimer levels. There was a positive association between suPAR and D-dimer (ß=7.34; P=0.002). Adjusted for clinical covariables, including D-dimer, the odds of VTE were 168% higher comparing the third with first suPAR tertiles (adjusted odds ratio, 2.68 [95% CI, 1.51-4.75]; P<0.001). Findings were consistent when stratified by D-dimer levels and in survival analysis accounting for death as a competing risk. On the basis of predicted probabilities from random forest, a decision tree found the combined D-dimer <1 mg/L and suPAR <11 ng/mL cutoffs, identifying 41% of patients with only 3.6% VTE probability. Conclusions Higher suPAR was associated with incident VTE independently of D-dimer in patients hospitalized for COVID-19. Combining suPAR and D-dimer identified patients at low VTE risk. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04818866.

SCD14-ST and New Generation Inflammatory Biomarkers in the Prediction of COVID-19 Outcome.

Since no definitive cure for COVID-19 is available so far, one of the challenges against the disease is understanding the clinical features and the laboratory inflammatory markers that can differentiate among different severity grades of the disease. The aim of the present study is a comprehensive and longitudinal evaluation of SCD14-ST and other new inflammatory markers, as well as cytokine storm molecules and current inflammatory parameters, in order to define a panel of biomarkers that could be useful for a better prognostic prediction of COVID-19 mortality. SCD14-ST, as well as the inflammatory markers IL-6, IL-10, SuPAR and sRAGE, were measured in plasma-EDTA of ICU COVID-19 positive patients. In this longitudinal study, SCD14-ST resulted significantly higher in patients who eventually died compared to those who were discharged from the ICU. The results suggest that the new infection biomarker SCD14-ST, in addition to new generation inflammatory biomarkers, such as SuPAR, sRAGE and the cytokines IL-6 and IL-10, can be a useful prognostic tool associated with canonical inflammatory parameters, such as CRP, to predict SARS-CoV-2 outcome in ICU patients.

Facilitating Safe Discharge Through Predicting Disease Progression in Moderate Coronavirus Disease 2019 (COVID-19): A Prospective Cohort Study to Develop and Validate a Clinical Prediction Model in Resource-Limited Settings.

BACKGROUND: In locations where few people have received coronavirus disease 2019 (COVID-19) vaccines, health systems remain vulnerable to surges in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Tools to identify patients suitable for community-based management are urgently needed. METHODS: We prospectively recruited adults presenting to 2 hospitals in India with moderate symptoms of laboratory-confirmed COVID-19 to develop and validate a clinical prediction model to rule out progression to supplemental oxygen requirement. The primary outcome was defined as any of the following: SpO2 < 94%; respiratory rate > 30 BPM; SpO2/FiO2 < 400; or death. We specified a priori that each model would contain three clinical parameters (age, sex, and SpO2) and 1 of 7 shortlisted biochemical biomarkers measurable using commercially available rapid tests (C-reactive protein [CRP], D-dimer, interleukin 6 [IL-6], neutrophil-to-lymphocyte ratio [NLR], procalcitonin [PCT], soluble triggering receptor expressed on myeloid cell-1 [sTREM-1], or soluble urokinase plasminogen activator receptor [suPAR]), to ensure the models would be suitable for resource-limited settings. We evaluated discrimination, calibration, and clinical utility of the models in a held-out temporal external validation cohort. RESULTS: In total, 426 participants were recruited, of whom 89 (21.0%) met the primary outcome; 257 participants comprised the development cohort, and 166 comprised the validation cohort. The 3 models containing NLR, suPAR, or IL-6 demonstrated promising discrimination (c-statistics: 0.72-0.74) and calibration (calibration slopes: 1.01-1.05) in the validation cohort and provided greater utility than a model containing the clinical parameters alone. CONCLUSIONS: We present 3 clinical prediction models that could help clinicians identify patients with moderate COVID-19 suitable for community-based management. The models are readily implementable and of particular relevance for locations with limited resources.

Circulating suPAR associates with severity and in-hospital progression of COVID-19.

BACKGROUND: COVID-19 disease progression is characterized by hyperinflammation and risk stratification may aid in early aggressive treatment and advanced planning. The aim of this study was to assess whether suPAR and other markers measured at hospital admission can predict the severity of COVID-19. METHODS: The primary outcome measure in this international, multi-centre, prospective, observational study with adult patients hospitalized primarily for COVID-19 was the association of WHO Clinical Progression Scale (WHO-CPS) with suPAR, ferritin, CRP, albumin, LDH, eGFR, age, procalcitonin, and interleukin-6. Admission plasma suPAR levels were determined using the suPARnostic® ELISA and suPARnostic® Turbilatex assays. RESULTS: Seven hundred and sixty-seven patients, 440 (57.4%) males and 327 (42.6%) females, were included with a median age of 64 years. Log-suPAR levels significantly correlated with WHO-CPS score, with each doubling of suPAR increasing the score by one point (p < .001). All the other markers were also correlated with WHO-CPS score. Admission suPAR levels were significantly lower in survivors (7.10 vs. 9.63, 95% CI 1.47-3.59, p < .001). A linear model (SALGA) including suPAR, serum albumin, serum lactate dehydrogenase, eGFR, and age can best estimate the WHO-CPS score and survival. Combining all five parameters in the SALGA model can improve the accuracy of discrimination with an AUC of 0.80 (95% CI: 0.759-0.836). CONCLUSIONS: suPAR levels significantly correlated with WHO-CPS score, with each doubling of suPAR increasing the score by one point. The SALGA model may serve as a quick tool for predicting disease severity and survival at admission.

Development and validation of SCOPE score: A clinical score to predict COVID-19 pneumonia progression to severe respiratory failure.

Most patients infected with SARS-CoV-2 (COVID-19) experience mild, non-specific symptoms, but many develop severe symptoms associated with an excessive inflammatory response. Elevated plasma concentrations of soluble urokinase plasminogen activator receptor (suPAR) provide early warning of progression to severe respiratory failure (SRF) or death, but access to suPAR testing may be limited. The Severe COvid Prediction Estimate (SCOPE) score, derived from circulating concentrations of C-reactive protein, D- dimers, interleukin-6, and ferritin among patients not receiving non-invasive or invasive mechanical ventilation during the SAVE-MORE study, offers predictive accuracy for progression to SRF or death within 14 days comparable to that of a suPAR concentration of ≥6 ng/mL (area under receiver operator characteristic curve 0.81 for both). The SCOPE score is validated in two similar independent cohorts. A SCOPE score of 6 or more is an alternative to suPAR for predicting progression to SRF or death within 14 days of hospital admission for pneumonia, and it can be used to guide treatment decisions.

Plasma Gradient of Soluble Urokinase-Type Plasminogen Activator Receptor Is Linked to Pathogenic Plasma Proteome and Immune Transcriptome and Stratifies Outcomes in Severe COVID-19.

Disease caused by SARS-CoV-2 coronavirus (COVID-19) led to significant morbidity and mortality worldwide. A systemic hyper-inflammation characterizes severe COVID-19 disease, often associated with acute respiratory distress syndrome (ARDS). Blood biomarkers capable of risk stratification are of great importance in effective triage and critical care of severe COVID-19 patients. Flow cytometry and next-generation sequencing were done on peripheral blood cells and urokinase-type plasminogen activator receptor (suPAR), and cytokines were measured from and mass spectrometry-based proteomics was done on plasma samples from an Indian cohort of COVID-19 patients. Publicly available single-cell RNA sequencing data were analyzed for validation of primary data. Statistical analyses were performed to validate risk stratification. We report here higher plasma abundance of suPAR, expressed by an abnormally expanded myeloid cell population, in severe COVID-19 patients with ARDS. The plasma suPAR level was found to be linked to a characteristic plasma proteome, associated with coagulation disorders and complement activation. Receiver operator characteristic curve analysis to predict mortality identified a cutoff value of suPAR at 1,996.809 pg/ml (odds ratio: 2.9286, 95% confidence interval 1.0427-8.2257). Lower-than-cutoff suPAR levels were associated with a differential expression of the immune transcriptome as well as favorable clinical outcomes, in terms of both survival benefit (hazard ratio: 0.3615, 95% confidence interval 0.1433-0.912) and faster disease remission in our patient cohort. Thus, we identified suPAR as a key pathogenic circulating molecule linking systemic hyperinflammation to the hypercoagulable state and stratifying clinical outcomes in severe COVID-19 patients with ARDS.

Association of Multiple Plasma Biomarker Concentrations with Progression of Prevalent Diabetic Kidney Disease: Findings from the Chronic Renal Insufficiency Cohort (CRIC) Study.

BACKGROUND: Although diabetic kidney disease is the leading cause of ESKD in the United States, identifying those patients who progress to ESKD is difficult. Efforts are under way to determine if plasma biomarkers can help identify these high-risk individuals. METHODS: In our case-cohort study of 894 Chronic Renal Insufficiency Cohort Study participants with diabetes and an eGFR of <60 ml/min per 1.73 m2 at baseline, participants were randomly selected for the subcohort; cases were those patients who developed progressive diabetic kidney disease (ESKD or 40% eGFR decline). Using a multiplex system, we assayed plasma biomarkers related to tubular injury, inflammation, and fibrosis (KIM-1, TNFR-1, TNFR-2, MCP-1, suPAR, and YKL-40). Weighted Cox regression models related biomarkers to progression of diabetic kidney disease, and mixed-effects models estimated biomarker relationships with rate of eGFR change. RESULTS: Median follow-up was 8.7 years. Higher concentrations of KIM-1, TNFR-1, TNFR-2, MCP-1, suPAR, and YKL-40 were each associated with a greater risk of progression of diabetic kidney disease, even after adjustment for established clinical risk factors. After accounting for competing biomarkers, KIM-1, TNFR-2, and YKL-40 remained associated with progression of diabetic kidney disease; TNFR-2 had the highest risk (adjusted hazard ratio, 1.61; 95% CI, 1.15 to 2.26). KIM-1, TNFR-1, TNFR-2, and YKL-40 were associated with rate of eGFR decline. CONCLUSIONS: Higher plasma levels of KIM-1, TNFR-1, TNFR-2, MCP-1, suPAR, and YKL-40 were associated with increased risk of progression of diabetic kidney disease; TNFR-2 had the highest risk after accounting for the other biomarkers. These findings validate previous literature on TNFR-1, TNFR-2, and KIM-1 in patients with prevalent CKD and provide new insights into the influence of suPAR and YKL-40 as plasma biomarkers that require validation.

RAGE and αVß3-integrin are essential for suPAR signaling in podocytes.

The soluble urokinase plasminogen activator receptor (suPAR) has been implicated in the pathogenesis of kidney diseases including primary and recurrent focal and segmental glomerulosclerosis (FSGS), diabetic nephropathy, and acute kidney injuries (AKI). Elevated serum suPAR concentration is a negative prognostic indicator in multiple critical clinical conditions. This study has examined the initial transduction steps used by suPAR in cultured mouse podocytes. We now report that the receptor for advanced glycation end-products (RAGE) co-immunoprecipitates with αV and ß3 integrin subunits, which have been previously shown to initiate suPAR signal transduction at the podocyte cell surface. siRNA knock-down of RAGE attenuated Src phosphorylation evoked by either suPAR or by glycated albumin (AGE-BSA), a prototypical RAGE agonist. suPAR effects on Src phosphorylation were also blocked by the structurally dissimilar RAGE antagonists FPS-ZM1 and azeliragon, as well as by cilengitide, an inhibitor of outside-in signaling through αV-integrins. FPS-ZM1 also blocked Src phosphorylation evoked by AGE-BSA. FPS-ZM1 blocked increases in cell surface TRPC6 abundance, cytosolic reactive oxygen species (ROS) and activation of the small GTPase Rac1 evoked by either suPAR or AGE-BSA. In addition, FPS-ZM1 inhibited Src phosphorylation evoked by serum collected from a patient with recurrent FSGS during a relapse. The magnitude of this inhibition was indistinguishable from the effect produced by a neutralizing antibody against suPAR. These data suggest that orally bioavailable small molecule RAGE antagonists could represent a useful therapeutic strategy for a wide range of clinical conditions associated with elevated serum suPAR, including primary FSGS and AKI.

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.

Early treatment of COVID-19 with anakinra guided by soluble urokinase plasminogen receptor plasma levels: a double-blind, randomized controlled phase 3 trial.

Early increase of soluble urokinase plasminogen activator receptor (suPAR) serum levels is indicative of increased risk of progression of coronavirus disease 2019 (COVID-19) to respiratory failure. The SAVE-MORE double-blind, randomized controlled trial evaluated the efficacy and safety of anakinra, an IL-1α/ß inhibitor, in 594 patients with COVID-19 at risk of progressing to respiratory failure as identified by plasma suPAR ≥6 ng ml-1, 85.9% (n = 510) of whom were receiving dexamethasone. At day 28, the adjusted proportional odds of having a worse clinical status (assessed by the 11-point World Health Organization Clinical Progression Scale (WHO-CPS)) with anakinra, as compared to placebo, was 0.36 (95% confidence interval 0.26-0.50). The median WHO-CPS decrease on day 28 from baseline in the placebo and anakinra groups was 3 and 4 points, respectively (odds ratio (OR) = 0.40, P < 0.0001); the respective median decrease of Sequential Organ Failure Assessment (SOFA) score on day 7 from baseline was 0 and 1 points (OR = 0.63, P = 0.004). Twenty-eight-day mortality decreased (hazard ratio = 0.45, P = 0.045), and hospital stay was shorter.