ST2 Is a Biomarker of Pediatric Pulmonary Arterial Hypertension Severity and Clinical Worsening

Increased Body Mass Index Augments Endothelial Injury and Clinical Outcomes after Hematopoietic Stem Cell Transplantation

Higher body mass index (BMI) is characterized as a chronic inflammatory state with endothelial dysfunction. Endothelial injury after allogeneic hematopoietic stem cell transplantation (allo-HSCT) puts patients at risk for such complications as transplantation-associated thrombotic microangiopathy (TA-TMA) and acute graft-versus-host-disease (aGVHD). To evaluate the impact of increased BMI on endothelial injury after allo-HSCT in pediatric and young adult patients, we conducted a retrospective cohort study evaluating 476 consecutive allo-HSCT children and young adult recipients age 0 to 20 years. Our analysis was subdivided based on distinct age categories (<2 years and 2 to 20 years). BMI was considered as a variable but was also expressed in standard deviations from the mean adjusted for age and sex (z-score), based on established criteria from the World Health Organization (age <2 years) and the Centers for Disease Control and Prevention (age 2 to 20 years) to account for differences associated with age. Primary endpoints included the incidences of TA-TMA and aGVHD. Increased BMI z-score was associated with TA-TMA after allo-HSCT in patients age <2 years (median, 18.1; IQR, 17 to 20; P = .006) and in patients age 2 to 20 years (median, 18.7; IQR, 16 to 21.9; P = .02). Higher BMI z-score correlated with TA-TMA risk in both age groups, with a BMI z-score of .9 in the younger cohort and .7 (IQR, -.4 to 1.6; P = .04) in the older cohort. Increased BMI z-score was associated with an increased risk of TA-TMA in a multivariate analysis of the entire cohort (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.05 to 1.37; P = .008). Multivariate analysis also demonstrated that patients with BMI in the 85th percentile or greater had an increased risk of developing TA-TMA compared to those with a lower BMI percentile (OR, 2.66; 95% CI, 1.62 to 4.32; P < .001). Baseline and day +7 ST2 levels were elevated in subjects with TA-TMA compared to those without TA-TMA in both age groups. Baseline sC5b-9 concentration was not correlated with BMI z-score, but sC5b-9 concentration was increased markedly by 7 days post-allo-HSCT in patients age <2 years who later developed TA-TMA compared to those who never developed TA-TMA (P = .001). The median BMI z-score was higher for patients with aGVHD compared to patients without aGVHD (.7 [range, -3.9 to 3.9] versus .2 [range, -7.8 to 5.4]; P = .03). We show that high BMI is associated with augmented risk of endothelial injury after HSCT, specifically TA-TMA. These data identify a high-risk population likely to benefit from early interventions to prevent endothelial injury and prompt treatment of established endothelial injury.

The ST2/IL-33 Pathway in Adult and Paediatric Heart Disease and Transplantation

ST2 is a member of interleukin 1 receptor family with soluble sST2 and transmembrane ST2L isoforms. The ligand of ST2 is IL-33, which determines the activation of numerous intracytoplasmic mediators following the binding with ST2L and IL-1RAcP, leading to nuclear signal and cardiovascular effect. Differently, sST2 is released in the blood and works as a decoy receptor, binding IL-33 and blocking IL-33/ST2L interaction. sST2 is mainly involved in maintaining homeostasis and/or alterations of different tissues, as counterbalance/activation of IL-33/ST2L axis is typically involved in the development of fibrosis, tissue damage, inflammation and remodeling. sST2 has been described in different clinical reports as a fundamental prognostic marker in patients with cardiovascular disease, as well as marker for the treatment monitoring of patients with heart failure; however, further studies are needed to better elucidate its role. In this review we reported the current knowledge about its role in coronary artery disease, heart failure, heart transplantation, heart valve disease, pulmonary arterial hypertension, and cardiovascular interventions.

Risk stratification in adult and pediatric pulmonary arterial hypertension: A systematic review

Introduction

Currently, risk stratification is the cornerstone of determining treatment strategy for patients with pulmonary arterial hypertension (PAH). Since the 2015 European Society of Cardiology/European Respiratory Society (ESC/ERS) guidelines for the diagnosis and treatment of pulmonary hypertension recommended risk assessment, the number of studies reporting risk stratification has considerably increased. This systematic review aims to report and compare the variables and prognostic value of the various risk stratification models for outcome prediction in adult and pediatric PAH.

Methods

A systematic search with terms related to PAH, pediatric pulmonary hypertension, and risk stratification was performed through databases PubMed, EMBASE, and Web of Science up to June 8, 2022. Observational studies and clinical trials on risk stratification in adult and pediatric PAH were included, excluding case reports/series, guidelines, and reviews. Risk of bias was assessed using the Prediction model Risk Of Bias Assessment Tool. Data on the variables used in the models and the predictive strength of the models given by c-statistic were extracted from eligible studies.

Results

A total of 74 studies were eligible for inclusion, with this review focusing on model development (n = 21), model validation (n = 13), and model enhancement (n = 9). The variables used most often in current risk stratification models were the non-invasive WHO functional class, 6-minute walk distance and BNP/NT-proBNP, and the invasive mean right atrial pressure, cardiac index and mixed venous oxygen saturation. C-statistics of current risk stratification models range from 0.56 to 0.83 in adults and from 0.69 to 0.78 in children (only two studies available). Risk stratification models focusing solely on echocardiographic parameters or biomarkers have also been reported.

Conclusion

Studies reporting risk stratification in pediatric PAH are scarce. This systematic review provides an overview of current data on risk stratification models and its value for guiding treatment strategies in PAH.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022316885], identifier [CRD42022316885].

Soluble Isoform of Suppression of Tumorigenicity 2 (ST2) Biomarker in a Large Cohort of Healthy Pediatric Population: Determination of Reference Intervals

Introduction: Only little data exists on ST2 reference intervals in healthy pediatric populations despite the high importance of this biomarker in adults with heart failure. The aim of the study was to assess the reference intervals of ST2 in a wide healthy pediatric cohort. Methods: We evaluated the serum concentrations of ST2 biomarker in 415 healthy pediatric subjects referred to our analysis laboratory. Subjects were categorized according to age (i.e., 0−6 (n = 79), 7−11 (n = 142) and 12−18 years (n = 191)) and sex. They were not suffering from any cardiac disorders, metabolic disorders, lung diseases, autoimmune disorders or malignancies. A written consent was obtained for each individual. No duplicate patients were included in the analysis and the presence of outliers was investigated. Reference intervals (Mean and central 95% confidence intervals) were determined. Results: Three outliers have been identified and removed from the analysis (60.0, 64.0 and 150.2 ng/mL). A total of 412 subjects were therefore included. The mean value for the whole population was 15.8 ng/mL (2.4−36.4 ng/mL). Males present a significantly higher mean concentration compared to females (17.2 versus 14.4 ng/mL, p = 0.001). A significant trend toward higher ST2 values with age was also observed, but for males only (r = 0.43, p < 0.0001). If considering age partitions, only males of 12−18 years (mean = 21.7 ng/mL) had significantly higher ST2 values compared to the other groups (ranging from 11.9 for males 0−6 years to 15.2 for females 12−18 years; p < 0.0001). Conclusions: We described age and sex-specific reference intervals for ST2 in a large healthy pediatric population. We found that ST2 values differ between sexes if considering all participants. A significant increase in ST2 with age was also observed, but only for males of 12−18 years.

Biomarkers of Pulmonary Hypertension Are Altered in Children with Down Syndrome and Pulmonary Hypertension

OBJECTIVE

To evaluate the performance of pulmonary hypertension (PH) biomarkers in children with Down syndrome, an independent risk factor for PH, in whom biomarker performance may differ compared with other populations.

STUDY DESIGN

Serum endostatin, interleukin (IL)-1 receptor 1 (ST2), galectin-3, N-terminal pro hormone B-natriuretic peptide (NT-proBNP), IL-6, and hepatoma-derived growth factor (HDGF) were measured in subjects with Down syndrome and PH (n = 29), subjects with Down syndrome and resolved PH (n = 13), subjects with Down syndrome without PH (n = 49), and subjects without Down syndrome with World Symposium on Pulmonary Hypertension group I pulmonary arterial hypertension (no Down syndrome PH group; n = 173). Each biomarker was assessed to discriminate PH in Down syndrome. A classification tree was created to distinguish PH from resolved PH and no PH in children with Down syndrome.

RESULTS

Endostatin, galectin-3, HDGF, and ST2 were elevated in subjects with Down syndrome regardless of PH status. Not all markers differed between subjects with Down syndrome and PH and subjects with Down syndrome and resolved PH. NT-proBNP and IL-6 levels were similar in the Down syndrome with PH group and the no Down syndrome PH group. A classification tree identified NT-proBNP and galectin-3 as the best markers for sequentially distinguishing PH, resolved PH, and no PH in subjects with Down syndrome.

CONCLUSIONS

Proteomic markers are used to improve the diagnosis and prognosis of PH but, as demonstrated here, can be altered in genetically unique populations such as individuals with Down syndrome. This further suggests that clinical biomarkers should be evaluated in unique groups with the development of population-specific nomograms.