Serum Levels of Soluble Urokinase Plasminogen Activator Receptor in Infants with Late-onset Sepsis

Advances in sepsis biomarkers

Sepsis, a dysregulated host immune response to an infectious agent, significantly increases morbidity and mortality for hospitalized patients worldwide. This chapter reviews (1) the basic principles of infectious diseases, pathophysiology and current definition of sepsis, (2) established sepsis biomarkers such lactate, procalcitonin and C-reactive protein, (3) novel, newly regulatory-cleared/approved biomarkers, such as assays that evaluate white blood cell properties and immune response molecules, and (4) emerging biomarkers and biomarker panels to highlight future directions and opportunities in the diagnosis and management of sepsis.

The accuracy of soluble urokinase-type plasminogen activator receptor for the diagnosis of neonatal sepsis: a meta-analysis

Background

Neonatal sepsis is one of the major causes of morbidity and mortality in newborns. However, atypical clinical manifestations and symptoms make the early diagnosis of neonatal sepsis a challenge. Relatively high-serum soluble urokinase-type plasminogen activator receptor (suPAR) has been implicated as a diagnostic biomarker for adult sepsis. Therefore, the meta-analysis is intended to explore the diagnostic value of suPAR for neonatal sepsis.

Methods

The PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure, China Biological Medicine Disk, and Wanfang databases were retrieved from inception to 31 December 2022 to collect diagnostic accuracy studies about suPAR for neonatal sepsis. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias in the included studies using the quality assessment of diagnostic accuracy studies-2 (QUADAS-2) tool. Then, a meta-analysis was performed using Stata 15.0 software.

Results

A total of six articles involving eight studies were included. The results of the meta-analysis showed that the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.89 [95%CI (0.83-0.93)], 0.94 [95%CI (0.77-0.98)], 14 [95%CI (3.5-55.2)], 0.12 [95%CI (0.08-0.18)], and 117 [95%CI (24-567)], respectively. The area under the curve (AUC) of summary receiver operator characteristic (SROC) curves was 0.92 [95%CI (0.90-0.94)]. Sensitivity analysis confirmed the stability of the results, and publication bias was not observed. Fagan's nomogram results demonstrated the clinical availability of the findings.

Conclusion

Current evidence suggests that suPAR has potential diagnostic value for neonatal sepsis. Owing to the limited quality of the included studies, more high-quality studies are needed to verify the above conclusion.

Evaluation of the relationship between KIM-1 and suPAR levels and clinical severity in COVID-19 patients: A different perspective on suPAR

Coronavirus disease 2019 (COVID-19) is one of the most pressing health problems of this century, but our knowledge of the disease is still limited. In this study, we aimed to examine serum-soluble urokinase plasminogen activator receptor (suPAR) and kidney injury molecule 1 (KIM-1) levels based on the clinical course of COVID-19. Our study included 102 patients over the age of 18 who were diagnosed as having COVID-19 between September 2020 and December 2020 and a control group of 50 health workers over the age of 18 whose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PCR results were negative. KIM-1 was measured by ELISA and suPAR by suPARnostic™ assay. Analysis of previously identified variables of prognostic significance in COVID-19 revealed high neutrophil to lymphocyte ratio, lactose dehydrogenase, prothrombin time, C-reactive protein, PaO₂ /FiO₂ , D-dimer, ferritin, and fibrinogen levels in patients with severe disease (p < 0.05 for all). KIM-1 and suPAR levels were significantly higher in COVID-19 patients compared to the control group (p = 0.001 for all). KIM-1 level was higher in severe patients compared to moderate patients (p = 0.001), while suPAR level was lower (p = 0.001). KIM-1, which is believed to play an important role in the endocytosis of SARS-CoV-2, was elevated in patients with severe COVID-19 and may be a therapeutic target in the future. SuPAR may have a role in defense mechanism and fibrinolysis, and low levels in severe patients may be associated with poor prognosis in the early period.

COVID-19 and pneumonia: a role for the uPA/uPAR system

Here, we highlight recent findings on the urokinase plasminogen activator (uPA)/uPA receptor (uPAR) system that suggest its potential role as a main orchestrator of fatal progression to pulmonary, kidney, and heart failure in patients with coronavirus. Patients with prolonged background inflammation can present aberrant inflammatory reactions, well recognized as the main factors that can result in death and probably sustained by a dysregulated uPA/uPAR system. SuPAR, the soluble form of uPAR, represents a biomarker of disease progression, and its levels correlate well with comorbidities associated with the death of patients with coronavirus. New drugs that regulate the uPA/uPAR system could help treat the severe complications of highly pathogenic human coronaviruses (hCoVs), including pandemic coronavirus 2019 (COVID-19).

Soluble urokinase-type plasminogen activator receptor as a biomarker of treatment response in childhood tuberculosis

Background

Childhood tuberculosis (TB) is a major health problem worldwide, especially in developing countries. In 2015, there are estimated 950,000 cases of childhood TB. Since most TB in children is paucibacillary, this gives rise not only to problem in diagnosing but also in monitoring the response to anti-TB treatment as well. Soluble urokinase-type plasminogen activator receptor (suPAR), a glycosylphosphatidylinositol-linked membrane protein of various cells of immune system, is one of the potential biomarkers to be used in the management of TB. The objective of this study is to study the decrease of serum suPAR level after anti-TB treatment in children with TB and its association with patient characteristics.

Methods

We conducted a prospective study on children suspected of having TB due to a history of contact with active TB case and symptoms such as coughing, fever, and enlarged lymph nodes. The diagnosis of TB is established by history, physical examination including anthropometric examination. Tuberculin skin test using PPD RT-23 and interferon-gamma releasing assay with Quantiferon TB-Gold Plus was performed. Chest X-rays were read by two independent radiologists. Microbiological examination was performed using microscopic examination and Xpert MTB/RIF. The level of suPAR before and after anti-TB treatment was examined with the Elisa method.

Results

There was no significant difference of serum suPAR levels before and after anti-TB treatment (mean 0.71 [standard deviation 0.585] ng/mL; P = 0.072). There was no association between ages (P = 0.112), nutritional status (P = 0.228), diagnosis of pulmonary or extrapulmonary TB (P = 0.956), and radiological feature (P = 0.810) with serum suPAR levels decrease.

Conclusion

There is no suPAR serum level decrease 2 months after treatment with anti-TB and there is no association with age, nutritional status, pulmonary or extrapulmonary TB diagnosis, and radiological feature.

C-reactive protein for diagnosing late-onset infection in newborn infants

BACKGROUND

Late-onset infection is the most common serious complication associated with hospital care for newborn infants. Because confirming the diagnosis by microbiological culture typically takes 24 to 48 hours, the serum level of the inflammatory marker C-reactive protein (CRP) measured as part of the initial investigation is used as an adjunctive rapid test to guide management in infants with suspected late-onset infection.

OBJECTIVES

To determine the diagnostic accuracy of serum CRP measurement in detecting late-onset infection in newborn infants.

SEARCH METHODS

We searched electronic databases (MEDLINE, Embase, and Science Citation Index to September 2017), conference proceedings, previous reviews, and the reference lists of retrieved articles.

SELECTION CRITERIA

We included cohort and cross-sectional studies evaluating the diagnostic accuracy of serum CRP levels for the detection of late-onset infection (occurring more than 72 hours after birth) in newborn infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility for inclusion, evaluated the methodological quality of included studies, and extracted data to estimate diagnostic accuracy using hierarchical summary receiver operating characteristic (SROC) models. We assessed heterogeneity by examining variability of study estimates and overlap of the 95% confidence interval (CI) in forest plots of sensitivity and specificity.

MAIN RESULTS

The search identified 20 studies (1615 infants). Most were small, single-centre, prospective cohort studies conducted in neonatal units in high- or middle-income countries since the late 1990s. Risk of bias in the included studies was generally low with independent assessment of index and reference tests. Most studies used a prespecified serum CRP threshold level as the definition of a 'positive' index test (typical cut-off level between 5 mg/L and 10 mg/L) and the culture of a pathogenic micro-organism from blood as the reference standard.At median specificity (0.74), sensitivity was 0.62 (95% CI 0.50 to 0.73). Heterogeneity was evident in the forest plots but it was not possible to conduct subgroup or meta-regression analyses by gestational ages, types of infection, or types of infecting micro-organism. Covariates for whether studies used a predefined threshold or not, and whether studies used a standard threshold of between 5 mg/L and 10 mg/L, were not statistically significant.

AUTHORS' CONCLUSIONS

The serum CRP level at initial evaluation of an infant with suspected late-onset infection is unlikely to be considered sufficiently accurate to aid early diagnosis or select infants to undergo further investigation or treatment with antimicrobial therapy or other interventions.

Biomarkers for diagnosis of neonatal sepsis: a literature review

Sepsis is an important cause of mortality and morbidity in neonatal populations. There has been constant search of an ideal sepsis biomarker that have high sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), so that both the diagnosis and exclusion of neonatal sepsis can be made at the earliest possible and appropriate antibiotics can be started to neonate. Ideal sepsis biomarker will help in guiding us when not to start antibiotics in case of suspect sepsis and total duration of antibiotics course in case of proven sepsis. There are numerous sepsis biomarkers that have been evaluated for early detection of neonatal sepsis but till date there is no single ideal biomarker that fulfills all essential criteria's for being an ideal biomarker. The most commonly used biomarkers are C-reactive protein (CRP) and procalcitonin (PCT), but both have shown varied sensitivity, specificity, PPV and NPV in different studies. We conducted literature search for various neonatal sepsis biomarkers and this review article will cover briefly all the markers with current available evidence.

Prognostic significance of APACHE II score and plasma suPAR in Chinese patients with sepsis: a prospective observational study

Background

Timely risk stratification is the key strategy to improve prognosis of patients with sepsis. Previous study has proposed to develop a powerful risk assessment rule by the combination of Acute Physiology and Chronic Health Evaluation II (APACHE II) score and plasma soluble urokinase plasminogen activator receptor (suPAR). That reaffirmation of suPAR as a prognostic marker in Chinese patients with severe sepsis is the aim of the study.

Methods

A total of 137 consecutive Chinese patients with sepsis were enrolled in a prospective study cohort. Demographic and clinical characteristics, conventional risk factors and important laboratory data were prospectively recorded. Sequential plasma suPAR concentrations were measured by an enzymeimmunoabsorbent assay on days 1, 3, and 7 after admission to the intensive care unit (ICU). Receiver operating characteristic (ROC) curves and Cox regression analysis were used to examine the performance of suPAR in developing a rule for risk stratification.

Results

The results showed that plasma suPAR concentrations remained relatively stable within survivors and non-survivors during the first week of disease course. Regression analysis indicated that APACHE II ≥15 and suPAR ≥10.82 ng/mL were independently associated with unfavorable outcome. With the above cutoffs of APACHE II and suPAR, strata of disease severity were determined. The mortality of each stratum differed significantly from the others.

Conclusions

Combination of APACHE II score and suPAR may supply the powerful prognostic utility for the mortality of sepsis.