Serum sRAGE as a potential biomarker for pediatric bronchiolitis: a pilot study

Soluble Receptor of Advanced Glycation End-Products (sRAGE) in Pediatric Asthma: A Prospective Study in 68 Children Aged 7 Years

Background: Asthma is a chronic inflammatory disease of the airways common in children. Soluble advanced glycation end-product receptor (sRAGE) is a blood biomarker of lung damage and inflammation. We sought to determine whether it could also be a biomarker in childhood asthma. Methods: We conducted a prospective, observational, analytical study at Clermont-Ferrand University Hospital. We measured plasma sRAGE levels in asthmatic and healthy children aged 7 years. Results: Of the 68 children assessed, 15 (22.05%) presented asthma. All presented normal respiratory function. The mean plasma sRAGE level was 1875 pg/mL in the children with asthma and 1794 pg/mL in the healthy children (p = 0.525). The mean plasma sRAGE level was significantly decreased with tobacco exposure during pregnancy: 1478 pg/mL versus 1870 pg/mL without (p = 0.007). Lower levels were observed in children living in apartments (1557 pg/mL) than in those living in houses (1863 pg/mL) (p = 0.031). Conclusions: No difference was observed in plasma sRAGE levels in children with asthma in our well-treated and controlled population. Environmental exposure may affect these levels. Further studies are required to better characterize the role of sRAGE.

Serum sRAGE and sE-selectin levels are useful biomarkers of lung injury and prediction of mortality in calves with perinatal asphyxia

The objective of the present study was to evaluate the biomarkers specific to lung endothelial and epithelial damage in the determination of lung injury and its severity in calves with perinatal asphyxia and to evaluate their prognostic importance among survivors and non-survivor calves. Ten healthy calves and 20 calves with perinatal asphyxia were enrolled in the study. Clinical examination and laboratory analysis were performed at admission. Serum concentrations of soluble advanced glycation end-product receptor (sRAGE), soluble E-selectin (sE-selectin), clara cell secretory protein (CC16), and soluble intercellular adhesion molecule-1 (sICAM-1) were measured to assess lung injury. Venous pH, sO₂, HCO₃, and BE of calves with perinatal asphyxia were significantly lower than the healthy calves. sRAGE, sE-selectin, pCO₂, and lactate were significantly high in calves with asphyxia. ROC analysis showed that sRAGE, sE-selectin, pCO₂, lactate, and respiratory rate were higher while HCO₃ and BE were lower in the nonsurvivor calves than survivors. In conclusion, serum sRAGE and sE-selectin concentrations highlight the utility of these biomarkers in determining lung injury in calves with asphyxia. Also, pH, pCO₂, lactate, HCO₃, BE, and respiratory rate along with serum sRAGE and sE-selectin were useful indicators in the prediction of mortality.

Use of procalcitonin and C-reactive protein in the diagnosis of bacterial infection in infants with severe bronchiolitis

The objective was to evaluate the use of procalcitonin (PCT) and C-reactive protein (CRP) for the diagnosis of bacterial infection in bronchiolitis patients. A prospective, single-centre, descriptive, and comparative observational study was carried out on patients with severe bronchiolitis admitted to the paediatric intensive care unit (PICU), from January 2011 to July 2017. Two cohorts were compared: patients with invasive bacterial infection (IBI) and patients with no bacterial infection (NBI). We included 675 patients, 399 of whom were males (59.1%), with median age of 47 days (IQR 25-100.3). Of them, 181 patients were diagnosed with IBI (26.8%). Seventy-two had sepsis (10.7%), 106 had pneumonia (15.7%), and 41 had a urinary tract infection (6.1%). PCT and CRP values were significantly higher in patients with IBI. ROC curves compared the ability of PCT and CRP to diagnose IBI at admission, 24 h, and 48 h. PCT showed a better AUC for diagnosing IBI, with statistically significant differences at all time points (p < 0.001). The best PCT cut-off for IBI diagnosis at admission was 1.4 ng/mL, with a sensitivity of 69% (95% CI 58.4-74.9) and a specificity of 91% (95% CI 88.1-92.5). Procalcitonin showed a better AUC for diagnosing both sepsis and pneumonia, which makes it an excellent predictor.Conclusion: We present PCT as a novel test in comparison with the traditional CRP screening test to discern which bronchiolitis patients have IBI. We highlight the importance of PCT for the diagnosis of pneumonia and sepsis, as it proved to be more sensitive and specific than CRP, with statistically significant differences. What is Known: • Bronchiolitis should be treated with antibiotics only when a bacterial infection is present. • The rate of antibiotic prescription in severe bronchiolitis is extremely high, so diagnostic tools are needed. What is New: • PCT is a good biomarker to discern which bronchiolitis patients have IBI, specially for pneumonia and sepsis diagnoses. It is more sensitive and specific than CRP, with statistically significant differences. • Implementation of PCT cut-off values may prevent unnecessary antibiotic use.

sRAGE as severe acute bronchiolitis biomarker, prospective observational study

INTRODUCTION AND OBJECTIVES

Acute bronchiolitis (AB) is the leading cause of hospitalization in infants and around 5% require intensive care treatment. Early identification of children diagnosed with AB at a high risk of severe progression is of great interest. The receptor for advanced glycation end products (RAGE), highly expressed in lung tissue, regulates immune responses and inflammation, and its soluble form, sRAGE, is believed to have an anti-inflammatory role. We hypothesized serum sRAGE might be a major determinant of AB severity and prognosis. This study was conducted to measure serum sRAGE in infants with severe AB and to assess its correlation with clinical severity, immediate complications, and outcome.

METHODS

Single-center, prospective, observational study of hospitalized children with severe bronchiolitis admitted to the Pediatric Intensive Care Unit (PICU), from September 2015 to September 2016.

RESULTS

A total of 52 children and 27 controls were included. The cases age ranged from 11 days to 21 months, resulting in a significant age difference with controls (11.85 vs 4.84 months, P < .01). Serum levels of sRAGE were lower but not significant in severe AB patients than in controls (1350.93 vs 1450.42 pg/mL; P = .399). No correlation was found between serum sRAGE and causative viruses, clinical symptoms, Wood-Downes score (a clinical severity score) on admission, respiratory support, or length of hospital stay. Serum sRAGE was also lower in the cases having had a previous respiratory disease (1463.84 vs 1072.43 pg/mL; P = .049). However, it was higher in patients with any lung consolidation on the chest X-ray (1584.79 vs 1131.62 pg/mL; P = .044) and weakly positively correlated with classical biomarkers (maximum C-reactive protein, +0.295, P = .034; maximum procalcitonin, +0.309; P = .029).

CONCLUSION

This single-center study reveals that sRAGE couldn't predict AB severity or outcome in children hospitalized at PICU. Nevertheless, it significantly increased in the presence of any lung consolidation and had a positive correlation with classical biomarkers. The utility of sRAGE in this population could be probably elucidated with a better understanding of AGE-RAGE axis.

Serum soluble receptor for advanced glycation end-products (sRAGE) in infants with bronchiolitis: Associations with acute severity and recurrent wheeze

BACKGROUND

Although bronchiolitis contributes to substantial acute (e.g., intensive care use) and chronic (e.g., recurrent wheeze and infections) morbidities in young children, the pathobiology remains uncertain. We examined relations of serum soluble receptor for advanced glycation end-products (sRAGE) with acute and chronic morbidities of bronchiolitis and whether the effect of serum sRAGE on development of recurrent wheeze is mediated through acute severity.

METHODS

A multi-center, multi-year, prospective cohort study of infants hospitalized for bronchiolitis was analyzed. We measured serum sRAGE level at acute hospitalization and examined its association with intensive care use (use of mechanical ventilation and/or admission to intensive care unit) and development of recurrent wheeze by age 3 years. We performed causal mediation analysis to estimate indirect (mediation) and direct effects of sRAGE on recurrent wheeze.

RESULTS

In 886 infants with bronchiolitis, median age was 2.9 months. Overall, 15% underwent intensive care and 32% developed recurrent wheeze by age 3 years. In the multivariable model adjusting for 11 confounders, higher presenting sRAGE level was associated with significantly lower risk of intensive care use (OR for each one-log increment, 0.39; 95%CI 0.16-0.91; P=0.03) and significantly lower rate of recurrent wheeze (HR 0.58; 95%CI 0.36-0.94; P=0.03). In mediation analysis, the direct effect was significant (HR 0.60; 95%CI 0.37-0.97; P=0.04) while the indirect effect was not (P=0.30).

CONCLUSIONS

Serum sRAGE levels were inversely associated with acute and chronic morbidities of bronchiolitis. Effect of sRAGE on development of recurrent wheeze is potentially driven through pathways other than acute severity of bronchiolitis.

Immune biomarkers predicting bronchiolitis disease severity: A systematic review

Bronchiolitis is one of the leading causes of hospitalisation in infancy, with highly variable clinical presentations ranging from mild disease safely managed at home to severe disease requiring invasive respiratory support. Identifying immune biomarkers that can predict and stratify this variable disease severity has important implications for clinical prognostication/disposition. A systematic literature search of the databases Embase, PubMed, ScienceDirect, Web of Science, and Wiley Online Library was performed. English language studies that assessed the association between an immune biomarker and bronchiolitis disease severity among children aged less than 24 months were included. 252 distinct biomarkers were identified across 90 studies. A substantial degree of heterogeneity was observed in the bronchiolitis definitions, measures of disease severity, and study designs. 99 biomarkers showed some significant association with disease severity, but only 18 were significant in multiple studies. However, all of these candidate biomarkers had comparable studies that reported conflicting results. Conclusion: The heterogeneity among included studies and the lack of a consistently significant biomarker highlight the need for consensus on bronchiolitis definitions and severity measures, as well as further studies assessing their clinical utility both in isolation and in combination.

[Method for predicting perinatal hypoxic lesions of the central nervous system in newborns.]

Perinatal lesions of the Central nervous system (CNS) in newborns occupy a leading place in the structure of perinatal morbidity and subsequent disability of children. To identify the features of the content of sRAGE in pregnant women with threatening preterm labor (UPR) in the period of 22-27 weeks, who subsequently gave birth to children with perinatal CNS lesion. Serum of venous blood of pregnant women with UPR at the term of 22-27 weeks was determined by ELISA once the content of sRAGE. If the value of sRAGE in pregnant women is 659.5 PG/ml or less, perinatal hypoxic lesions of the Central nervous system in newborns are predicted with an accuracy of 75.8% (sensitivity of 82.6%, specificity of 66.7%).

Serum soluble receptor for advanced glycation end-products during acute bronchiolitis in infant: Prospective study in 93 cases

INTRODUCTION

Acute bronchiolitis is a major cause of acute respiratory distress in infants. The soluble receptor for advanced glycation end-products (sRAGE) is a biomarker of pulmonary damage processes, with a diagnostic and a prognostic value in acute respiratory distress syndrome (ARDS). The RAGE pathway is also implicated in the pathogenesis of other respiratory diseases like asthma, but the value of sRAGE levels in acute bronchiolitis remains under-investigated.

MATERIAL AND METHODS

A prospective, observational, and analytical study was conducted at Clermont-Ferrand University Hospital. The main objective was to evaluate the correlation between serum sRAGE and clinical severity of bronchiolitis in hospitalized infants aged <1 year. We analyzed correlations between serum sRAGE and Wainwright score, short-term morbidity attributable to bronchiolitis, causal viruses and risk for recurrent wheezing at 1 year.

RESULTS

The study included 93 infants. sRAGE levels were significantly lower in acute bronchiolitis patients (mean 1101 pg/mL) than in controls (2203 pg/mL, P < 0.001) but did not correlate with clinical severity. No correlation was found between serum sRAGE and severity score, respiratory viruses, and recurrent wheezing at 1 year. Serum sRAGE levels were negatively correlated with age (r = -0.45, P < 0.001).

CONCLUSION

Serum sRAGE levels are decreased in acute bronchiolitis but not correlated with disease severity. sRAGE levels should be age-adjusted in infants. Serum sRAGE levels measured in the setting of acute bronchiolitis were not predictive of recurrent wheezing.

Circulating soluble RAGE and cell surface RAGE on peripheral blood mononuclear cells in healthy children

BACKGROUND

The receptor for advanced glycation end products (RAGE) has a critical role in the pathogenesis of inflammation. In healthy children, its basal expression on the peripheral blood mononuclear cell (PBMC) and the basal circulating soluble RAGE (sRAGE) levels are unknown. The aim of this study was to describe both.

METHODS

This is a monocentric, observational and descriptive study of samples obtained from healthy children. The RAGE expression on PBMC was analyzed using flow cytometry. The sRAGE values were determined with a specific sandwich enzyme-linked immunosorbent assay (ELISA) kit, later the relation between cellular RAGE and sRAGE was described.

RESULTS

Forty-three children were included. The median sRAGE level was 849.0±579.0 pg/mL. The RAGE mean fluorescence intensity (MFI) was 1382±506 in monocytes and 792±506 in lymphocytes. There were no differences between genders. A negative correlation was found between sRAGE and RAGE MFI in lymphocytes (r=-0.3; p=0.04).

CONCLUSIONS

We describe for the first time the RAGE surface levels on PBMC in children. It showed a negative correlation with sRAGE. The sRAGE circulating level is lower than the sRAGE level described in adult population or non-healthy children. Our findings should be confirmed in order to apply them as reference values for future investigations.

Biomarkers in Pediatric ARDS: Future Directions

Acute respiratory distress syndrome (ARDS) is common among mechanically ventilated children and accompanies up to 30% of all pediatric intensive care unit deaths. Though ARDS diagnosis is based on clinical criteria, biological markers of acute lung damage have been extensively studied in adults and children. Biomarkers of inflammation, alveolar epithelial and capillary endothelial disruption, disordered coagulation, and associated derangements measured in the circulation and other body fluids, such as bronchoalveolar lavage, have improved our understanding of pathobiology of ARDS. The biochemical signature of ARDS has been increasingly well described in adult populations, and this has led to the identification of molecular phenotypes to augment clinical classifications. However, there is a paucity of data from pediatric ARDS (pARDS) patients. Biomarkers and molecular phenotypes have the potential to identify patients at high risk of poor outcomes, and perhaps inform the development of targeted therapies for specific groups of patients. Additionally, because of the lower incidence of and mortality from ARDS in pediatric patients relative to adults and lack of robust clinical predictors of outcome, there is an ongoing interest in biological markers as surrogate outcome measures. The recent definition of pARDS provides additional impetus for the measurement of established and novel biomarkers in future pediatric studies in order to further characterize this disease process. This chapter will review the currently available literature and discuss potential future directions for investigation into biomarkers in ARDS among children.

Plasma Biomarker Analysis in Pediatric ARDS: Generating Future Framework from a Pilot Randomized Control Trial of Methylprednisolone: A Framework for Identifying Plasma Biomarkers Related to Clinical Outcomes in Pediatric ARDS

OBJECTIVE

Lung injury activates multiple pro-inflammatory pathways, including neutrophils, epithelial, and endothelial injury, and coagulation factors leading to acute respiratory distress syndrome (ARDS). Low-dose methylprednisolone therapy (MPT) improved oxygenation and ventilation in early pediatric ARDS without altering duration of mechanical ventilation or mortality. We evaluated the effects of MPT on biomarkers of endothelial [Ang-2 and soluble intercellular adhesion molecule-1 (sICAM-1)] or epithelial [soluble receptor for activated glycation end products (sRAGE)] injury, neutrophil activation [matrix metalloproteinase-8 (MMP-8)], and coagulation (plasminogen activator inhibitor-1).

DESIGN

Double-blind, placebo-controlled randomized trial.

SETTING

Tertiary-care pediatric intensive care unit (ICU).

PATIENTS

Mechanically ventilated children (0-18 years) with early ARDS.

INTERVENTIONS

Blood samples were collected on days 0 (before MPT), 7, and 14 during low-dose MPT (n = 17) vs. placebo (n = 18) therapy. The MPT group received a 2-mg/kg loading dose followed by 1 mg/kg/day continuous infusions from days 1 to 7, tapered off over 7 days; placebo group received equivalent amounts of 0.9% saline. We analyzed plasma samples using a multiplex assay for five biomarkers of ARDS. Multiple regression models were constructed to predict associations between changes in biomarkers and the clinical outcomes reported earlier, including P/F ratio on days 8 and 9, plateau pressure on days 1 and 2, PaCO2 on days 2 and 3, racemic epinephrine following extubation, and supplemental oxygen at ICU discharge.

RESULTS

No differences occurred in biomarker concentrations between the groups on day 0. On day 7, reduction in MMP-8 levels (p = 0.0016) occurred in the MPT group, whereas increases in sICAM-1 levels (p = 0.0005) occurred in the placebo group (no increases in sICAM-1 in the MPT group). sRAGE levels decreased in both MPT and placebo groups (p < 0.0001) from day 0 to day 7. On day 7, sRAGE levels were positively correlated with MPT group PaO2/FiO2 ratios on day 8 (r = 0.93, p = 0.024). O2 requirements at ICU transfer positively correlated with day 7 MMP-8 (r = 0.85, p = 0.016) and Ang-2 levels (r = 0.79, p = 0.036) in the placebo group and inversely correlated with day 7 sICAM-1 levels (r = -0.91, p = 0.005) in the MPT group.

CONCLUSION

Biomarkers selected from endothelial, epithelial, or intravascular factors can be correlated with clinical endpoints in pediatric ARDS. For example, MPT could reduce neutrophil activation (⇓MMP-8), decrease endothelial injury (⇔sICAM-1), and allow epithelial recovery (⇓sRAGE). Large ARDS clinical trials should develop similar frameworks.

TRIAL REGISTRATION

https://clinicaltrials.gov, NCT01274260.

Antifibrotic properties of receptor for advanced glycation end products in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive chronic interstitial lung disease with poor survival. Previous reports suggested the contributory effect of receptor for advanced glycation end products (RAGE) to the pathogenesis of IPF. But the findings are controversial. The present in vivo study with RAGE null mice, we further confirmed the evidence that lack of RAGE evolves worse bleomycin-induced pulmonary fibrosis compared with control mice. Moreover, RAGE null mice spontaneously developed similar pathogenesis of lung fibrosis via immunohistochemical staining. In addition, we investigated the negative roles of RAGE on epithelial-mesenchymal transition (EMT) indicated by elevated α-smooth muscle actin (α-SMA) and collagen-I (Col-I) deposition in A549 cell treated with transforming growth factor-β (TGF-β), all of which were blocked by sRAGE, a decoy receptor. Furthermore, interacting with the specific ligand as AGE, RAGE blocked TGF-β-induced activation of Smad2, ERK and JNK signals in A549 cells, which were also challenged by sRAGE administration. This present study confirmed an important role of RAGE in vivo and vitro models of pulmonary fibrosis and suggested the therapeutic possibility for pulmonary fibrosis via RAGE regulation.