Soluble ST2: A complex and diverse role in several diseases

Prediction of one-year adverse clinical outcomes by macrophage migration inhibitory factor in stemi patients

Biomarkers have taken one of the first places as diagnostic and prognostic tools in ST-segment elevation myocardial infarction (STEMI) and are consequently widely used as predictors of short-term and long-term prognosis. One of the promising biomarkers for early cardiovascular outcomes prediction is the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF). The aim of the study was to elucidate a plausible predictive value of the MIF levels for one-year clinical outcomes in STEMI patients who underwent primary percutaneous coronary intervention (PCI). Materials and methods. 134 STEMI patients were enrolled in the study after receiving voluntary informed consent. All patients underwent conventional investigations, and additionally, the MIF levels were determined at baseline, directly before and after PCI. During 1-year follow-up, 37 % of patients reached the endpoint, which was composite and included all-cause mortality, non-fatal myocardial infarction, non-fatal stroke, hospitalization for unstable angina, heart failure decompensation, and urgent revascularization. Results. We have found that pre-PCI MIF levels > 3934 pg/mL (AUC=0.7; 95 % CI 0.578 to 0.753; Youden index=0.31; p=0.008) might be an independent predictor of composite endpoints with sensitivity 54 % and specificity 82 %. A positive correlation between MIF and inflammatory biomarkers was revealed (WBC count r=0.33, p=0.0001; CRP r=0.19, p=0.032). Adverse outcomes associated with higher pre- and post-PCI MIF levels (OR 1.0, 95 % CI 1.0001–1.0008; p=0.013 and OR 1.0, 95 % CI 1.0001–1.0009; p=0.019) and CRP that determined during the first week after the event (OR 1.0, 95 % CI 1.005–1.2, p=0.03). Kaplan-Meier analysis has shown a substantially lower long-term survival rate in patients with a MIF level > 3493 pg/ml compared to a MIF level ≤ 3493 pg/ml (Log rank=0.00025). Conclusions. The MIF levels exceeding 3934 ng/ml were associated with a higher risk of one-year adverse clinical outcomes in STEMI patients who underwent primary PCI.

Soluble ST2 in coronary artery disease: Clinical biomarkers and treatment guidance

The IL-33/ST2 L signaling pathway is involved in the pathophysiological processes of several diseases and mainly exerts anti-inflammatory and antifibrotic effects. Soluble suppression of tumorigenicity 2 (sST2), which serves as a competitive inhibitory molecule of this pathway, is a member of the interleukin (IL)-1 family, a decoy receptor for IL33, thought to play a role in cardiac remodeling and the inflammatory process. However, the association between sST2 and coronary artery disease (CAD), one of the most common causes of heart failure, is still being explored. We therefore reviewed the research on sST2 in the field of CAD, including reflecting the atherosclerosis burden, predicting no-reflow, predicting prognosis, responding to myocardial remodeling, and guiding management, hoping to provide cardiologists with new perspectives.

Utility of cardiac bioenzymes in predicting cardiovascular outcomes in SARS-CoV-2

BACKGROUND

Cardiovascular complications have been increasingly recognized in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) associated coronavirus disease 2019 (COVID-19). Cardiac biomarkers are released because of this ongoing cardiovascular injury and can act as surrogate markers to assess the disease severity.

AIM

To review the variation and utility of these biomarkers in COVID-19 to ascertain their role in diagnosis, prognosis and clinical outcomes of the disease.

METHODS

We performed a literature search in PubMed, Medline and the Reference Citation Analysis (RCA), using the search terms "COVID-19" and "cardiac bioenzymes" or "cardiac biomarkers". Additionally, we also used the latest reference citation analysis tool to identify more articles.

RESULTS

Cardiac troponin has been consistently elevated in patients with COVID-19 associated myocarditis, and strongly correlated with adverse prognosis. Natri-uretic peptides including brain natriuretic peptide (BNP) and pro-BNP is elevated in patients with COVID-19 associated cardiac injury, irrespective of their prior heart failure status, and independently correlated with worst outcomes. Alongside these traditional biomarkers, novel cardiac bioenzymes including presepsin, soluble ST2 and copeptin, are also increasingly recognized as markers of cardiovascular injury in COVID-19 and can be associated with poor outcomes.

CONCLUSION

Assessment of cardiac bioenzymes at admission and their serial monitoring can help assess the severity of disease and predict mortality in patients with SARS-CoV-2 infection. Future studies are needed to elude the critical importance of novel biomarkers.

From Classic to Modern Prognostic Biomarkers in Patients with Acute Myocardial Infarction

Despite all the important advances in its diagnosis and treatment, acute myocardial infarction (AMI) is still one of the most prominent causes of morbidity and mortality worldwide. Early identification of patients at high risk of poor outcomes through the measurement of various biomarker concentrations might contribute to more accurate risk stratification and help to guide more individualized therapeutic strategies, thus improving prognoses. The aim of this article is to provide an overview of the role and applications of cardiac biomarkers in risk stratification and prognostic assessment for patients with myocardial infarction. Although there is no ideal biomarker that can provide prognostic information for risk assessment in patients with AMI, the results obtained in recent years are promising. Several novel biomarkers related to the pathophysiological processes found in patients with myocardial infarction, such as inflammation, neurohormonal activation, myocardial stress, myocardial necrosis, cardiac remodeling and vasoactive processes, have been identified; they may bring additional value for AMI prognosis when included in multi-biomarker strategies. Furthermore, the use of artificial intelligence algorithms for risk stratification and prognostic assessment in these patients may have an extremely important role in improving outcomes.

An IL1RL1 genetic variant lowers soluble ST2 levels and the risk effects of APOE-ε4 in female patients with Alzheimer's disease

Changes in the levels of circulating proteins are associated with Alzheimer's disease (AD), whereas their pathogenic roles in AD are unclear. Here, we identified soluble ST2 (sST2), a decoy receptor of interleukin-33-ST2 signaling, as a new disease-causing factor in AD. Increased circulating sST2 level is associated with more severe pathological changes in female individuals with AD. Genome-wide association analysis and CRISPR-Cas9 genome editing identified rs1921622 , a genetic variant in an enhancer element of IL1RL1, which downregulates gene and protein levels of sST2. Mendelian randomization analysis using genetic variants, including rs1921622 , demonstrated that decreased sST2 levels lower AD risk and related endophenotypes in females carrying the Apolipoprotein E (APOE)-ε4 genotype; the association is stronger in Chinese than in European-descent populations. Human and mouse transcriptome and immunohistochemical studies showed that rs1921622 /sST2 regulates amyloid-beta (Aβ) pathology through the modulation of microglial activation and Aβ clearance. These findings demonstrate how sST2 level is modulated by a genetic variation and plays a disease-causing role in females with AD.

Association of ST2 Elevation in the Early Third Trimester with Heart Failure and Pre-Eclampsia in the Peripartum Period

Background: Although high-risk pregnancies are common in clinical practice, there are limited data on the association of soluble suppression of tumorigenicity 2 (ST2) with pregnancy-related complications. The rates of maternal complications, including heart failure (HF) during the peripartum period, were evaluated according to the ST2 level. Methods: A single-center retrospective cohort study included and stratified 259 women with high-risk pregnancies in their early third trimester according to the ST2 levels. The primary endpoint was the occurrence of peripartum HF based on symptoms, N-terminal pro-brain natriuretic peptide, or echocardiography associated with fluid retention. The secondary endpoints consisted of pre-eclampsia, silent pleural effusion, and pericardial effusion during the peripartum period. We performed a logistic model for the association between ST2 and maternal complications. Results: Of the 259 patients (mean age: 36.4 years, mean gestational duration: 31.6 weeks), advanced age ≥35 years and twin gestation were the most prevalent risk factors. Patients with ST2 ≥ 35 ng/mL showed enlarged cardiac chambers. Peripartum HF occurred in 2 (1.6%) out of 121 patients with ST2 < 35 ng/mL and in 47 (34%) out of 138 patients with ST2 ≥ 35 ng/mL. Those with ST2 ≥ 35 ng/mL were more likely to have the secondary endpoints (40.6% vs. 5.8%, p < 0.001). After adjustment, ST2 ≥ 35 ng/mL was associated with a six-fold occurrence of peripartum HF and a four-fold increase in the secondary endpoints. Conclusions: In women with high-risk pregnancies, peripartum HF and pre-eclampsia were not uncommon, and ST2 ≥ 35 ng/mL in the third trimester was independently related to maternal complications.

Predictive Value of Soluble Growth Stimulator Gene 2 Protein for Coronary Slow Flow/No-Reflow in ST-Elevation Myocardial Infarction Patients Receiving Percutaneous Coronary Intervention

Background

Soluble growth stimulator gene 2 protein (sST2) is associated with heart failure and myocardial infarction; however, the predictive value of plasma sST2 level for coronary slow flow/no-reflow (CSF/NRF) is unclear. This study aimed to explore the predictive value of plasma sST2 levels for CSF/NRF in patients with ST-elevation myocardial infarction (STEMI) who underwent emergency percutaneous coronary intervention (PCI).

Methods

A total of 242 STEMI patients who underwent emergency PCI at our hospital between November 2020 and July 2021 were enrolled in this study. According to the postprocedural procedure, these patients were divided into the CSF/NRF and control groups. Clinical data were collected from both groups and were used to explore the predictive value of serum sST2 levels for CSF/NRF.

Results

Of the total 242 patients, CSF/NRF was observed in 50 patients (20.7%). Statistically significant differences (P < 0.05) were observed in age, diabetes mellitus, sST2 level, neutrophil-to-lymphocyte ratio (NLR), fasting blood sugar, preprocedural blood pressure, intraprocedural hypotension, N-terminal pro-B-type natriuretic peptide, MB isoenzyme of creatine kinase (CK-MB), and cardiac troponin I (cTNI). Multivariate analysis showed that the sST2 level, NLR, and intraoperative hypotension were independent risk factors for CSF/NRF. ROC curve analysis showed that the sensitivity and specificity of the sST2 level for predicting CSF/NRF were 68.0% and 75.5%, respectively, when the sST2 level was more than 64.6 ng/mL (AUC = 0.780, 95% CI: 1.003–1.020, P=0.009).

Conclusion

For STEMI patients, preprocedural sST2 levels significantly correlated with CSF/NRF occurring in PCI. sST2 level is a potential predictor for CSF/NRF occurrence.

An imbalance of the IL-33/ST2-AXL-efferocytosis axis induces pregnancy loss through metabolic reprogramming of decidual macrophages

During embryo implantation, apoptosis is inevitable. These apoptotic cells (ACs) are removed by efferocytosis, in which macrophages are filled with a metabolite load nearly equal to the phagocyte itself. A timely question pertains to the relationship between efferocytosis-related metabolism and the immune behavior of decidual macrophages (dMΦs) and its effect on pregnancy outcome. Here, we report positive feedback of IL-33/ST2-AXL-efferocytosis leading to pregnancy failure through metabolic reprogramming of dMΦs. We compared the serum levels of IL-33 and sST2, along with IL-33 and ST2, efferocytosis and metabolism of dMΦs, from patients with normal pregnancies and unexplained recurrent pregnancy loss (RPL). We revealed disruption of the IL-33/ST2 axis, increased apoptotic cells and elevated efferocytosis of dMΦs from patients with RPL. The dMΦs that engulfed many apoptotic cells secreted more sST2 and less TGF-β, which polarized dMΦs toward the M1 phenotype. Moreover, the elevated sST2 biased the efferocytosis-related metabolism of RPL dMΦs toward oxidative phosphorylation and exacerbated the disruption of the IL-33/ST2 signaling pathway. Metabolic disorders also lead to dysfunction of efferocytosis, resulting in more uncleared apoptotic cells and secondary necrosis. We also screened the efferocytotic molecule AXL regulated by IL-33/ST2. This positive feedback axis of IL-33/ST2-AXL-efferocytosis led to pregnancy failure. IL-33 knockout mice demonstrated poor pregnancy outcomes, and exogenous supplementation with mouse IL-33 reduced the embryo losses. These findings highlight a new etiological mechanism whereby dMΦs leverage immunometabolism for homeostasis of the microenvironment at the maternal-fetal interface.

IL-33 Promotes ST2-Dependent Fibroblast Maturation via P38 and TGF-β in a Mouse Model of Epidural Fibrosis

BACKGROUND

Recent evidence suggests that IL-33, a novel member of the IL-1β family, is involved in organ fibrosis. However, the roles of IL-33 and its receptor ST2 in epidural fibrosis post spine operation remain elusive.

METHODS

A mouse model of epidural fibrosis was established after laminectomy. IL-33 in the wound tissues post laminectomy was measured with Western blotting, ELISA and immunoflurosence imaging. The fibroblast cell line NIH-3T3 and primary fibroblasts were treated with IL-33 and the mechanisms of maturation of fibroblasts into myofibroblasts were analyzed. To explore roles of IL-33 and its receptor ST2 in vivo, IL-33 knockout (KO) and ST2 KO mice were employed to construct the model of laminectomy. The epidural fibrosis was evaluated using H&E and Masson staining, western-blotting, ELISA and immunohistochemistry.

RESULTS

As demonstrated in western blotting and ELISA, IL-33 was increased in epidural wound tissues post laminectomy. The immunoflurosence imaging revealed that endothelial cells (CD31⁺) and fibroblasts (α-SAM⁺) were major producers of IL-33 in the epidural wound tissues. In vitro, IL-33 promoted fibroblast maturation, which was blocked by ST2 neutralization antibody, suggesting that IL-33-promoted-fibroblasts maturation was ST2 dependent. Further, IL-33/ST2 activated MAPK p38 and TGF-β pathways. Either p38 inhibitor or TGF-β inhibitor decreased fibronectin and α-SAM production from IL-33-treated fibroblasts, suggesting that p38 and TGF-β were involved with IL-33/ST2 signal pathways in the fibroblasts maturation. In vivo, IL-33 KO or ST2 KO decreased fibronectin, α-SMA and collagen deposition in the wound tissues of mice that underwent spine surgery. In addition, TGF-β1 was decreased in IL-33 KO or ST2 KO epidural wound tissues.

CONCLUSION

In summary, IL-33/ST2 promoted fibroblast differentiation into myofibroblasts via MAPK p38 and TGF-β in a mouse model of epidural fibrosis after laminectomy.

IL33 and sST2 serum level in systemic sclerosis microvascular involvement

AIM

Endothelial dysfunction and microvascular damage are hallmarks of systemic sclerosis (SSc). Objective of this study was to evaluate IL33 and ST2 serum levels in SSc patients and healthy controls (HC). Secondary aim was to evaluate the IL33 axis in the SSc microvascular manifestation.

METHODS

IL33 and sST2 have been assessed in 46 SSc patients and 24 HC matched for sex and age. Main clinimetric indexes were assessed. Skin perfusion of hands was evaluated by Laser Speckle Contrast Analysis (LASCA) and echocolordoppler ultrasound of renal arteries was performed to evaluate subclinical renal involvement.

RESULTS

SSc patients had higher serum level of IL33 and sST2 than HC. IL33 and sST2 were significantly higher in SSc patient with digital ulcers (DUs) compared to SSc patients without DUs. SSc patients with late nailfold videocapillaroscopy (NVC) pattern had higher serum levels of sST2 than SSc patients with active NVC pattern. SSc patients without proximal-distal gradient (PDG) at LASCA had significantly higher sST2 serum level compared to SSc patients with PDG. SSc patients with renal resistive index (RRI) ≥ 0.70 had higher serum levels of sST2 than SSc patients with RRI < 0.70. A positive linear correlation was shown between sST2 and RRI, between sST2 and intrarenal S/D and between sST2 and PI. Kaplan-Meier curves show a significantly reduced free survival from DUs in patients with increased sST2 (p = 0.025). In multivariate analysis, sST2 is associated with the development of new DUs.

CONCLUSION

IL33 and sST2 are increased in SSc patients and ST2 might be a marker of microvascular damage.

Interleukin-33/ Suppression of Tumorigenicity 2 in Renal Fibrosis: Emerging Roles in Prognosis and Treatment

Chronic kidney disease (CKD) is a major public health problem that affects more than 10% of the population worldwide and has a high mortality rate. Therefore, it is necessary to identify novel treatment strategies for CKD. Incidentally, renal fibrosis plays a central role in the progression of CKD to end-stage renal disease (ESRD). The activation of inflammatory pathways leads to the development of renal fibrosis. In fact, interleukin-33 (IL-33), a newly discovered member of the interleukin 1 (IL-1) cytokine family, is a crucial regulator of the inflammatory process. It exerts pro-inflammatory and pro-fibrotic effects via the suppression of tumorigenicity 2 (ST2) receptor, which, in turn, activates other inflammatory pathways. Although the role of this pathway in cardiac, pulmonary, and hepatic fibrotic diseases has been extensively studied, its precise role in renal fibrosis has not yet been completely elucidated. Recent studies have shown that a sustained activation of IL-33/ST2 pathway promotes the development of renal fibrosis. However, with prolonged research in this field, it is expected that the IL-33/ST2 pathway will be used as a diagnostic and prognostic tool for renal diseases. In addition, the IL-33/ST2 pathway seems to be a new target for the future treatment of CKD. Here, we review the mechanisms and potential applications of the IL-33/ST2 pathway in renal fibrosis; such that it can help clinicians and researchers to explore effective treatment options and develop novel medicines for CKD patients.

IL-33 and Soluble ST2 Are Associated With Recurrent Spontaneous Abortion in Early Pregnancy

Normal pregnancy is related to the successful transition from type 1 cellular immunity to type 2 cellular immunity. Therefore, this study aimed to investigate whether there is abnormal expression of cytokines in the process of inducing Recurrent spontaneous abortion (RSA). Interleukin (IL)-33 is a new member of the IL-1 family, and ST2, as IL-33’s receptor, induced the production of type 2 cytokines. In this study, blood samples were collected from 19 non-pregnant women of normal childbearing age, 28 normal pregnant women, and 33 women with RSA. The serum concentrations of IL-33 and ST2 were detected by flow cytometry. Our results showed that the serum concentrations of IL-33 and ST2 in the RSA group were significantly higher than those in the healthy control group (IL-33: P < 0.05; ST2: P < 0.0001), and IL-33 and ST2 had a higher level in the process of RSA predictive value. In addition, this study initially found that the serum concentrations of IL-33 and ST2 were not significantly correlated with the number of weeks of pregnancy, and there was a lower correlation between IL-33 and ST2 during RSA. This result may be related to the small number of cases. This study is the first time to correlate the changes in serum concentrations of IL-33 and ST2 with RSA, which may be a novel biomarker for the prediction and treatment of RSA.

Differences in maternal soluble ST2 levels in the third trimester of normal pregnancy versus preeclampsia

BACKGROUND

Preeclampsia is associated with intense inflammatory response in pregnancy, and soluble ST2 (sST2) is pathologically increased in this condition. No data exist regarding maternal sST2 levels in normal pregnancy versus preeclampsia in areas of southeast Asia with an ethnic Malay predominance.

MATERIALS AND METHODS

Patients were sorted into normal pregnancy or preeclampsia. Patients with a history of allergic, inflammatory, or malignant disease were excluded. One sample was taken per patient; all samples were taken during the third trimester of pregnancy. Thirty samples from each group were enrolled in the study, totaling 60 samples. Soluble ST2 levels in maternal plasma were measured using the Presage® ST2 Assay according to manufacturer instructions, and data was analyzed using SPSS 23.

RESULTS

Patients in the preeclampsia group were significantly older than those in the normal pregnancy group (p = 0.01). Most patients with preeclampsia presented as early-onset (n = 23). Both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly higher (p < 0.001) in the preeclampsia group. Mean sST2 level in the preeclampsia group (85.89 ng/ml) was significantly higher than the normal pregnancy group mean (38.3 ng/ml) during the third trimester (p < 0.001). This study also found a correlation between sST2 and preeclampsia (p < 0.001, r = 0.480), SBP (p < 0.001, r = 0.407), and DBP (p = 0.007, r = 0.342), while preeclampsia was found to be the best explanatory variable of sST2 levels (r = 0.468, p < 0.001). sST2 level> 63.66 ng/ml has sensitivity 50% and specificity 93.3%, with AUC of 0.78 [95% CI 0.66 - 0.90], p < 0.001. The sST2 > 63.66 ng/ml has an OR of 14.0 [95% CI 2.82 - 69.6], p < 0.001 for preeclampsia. The dose-response relationship between sST2 level and preeclampsia was linear.

CONCLUSION

Soluble ST2 levels were increased in both normal pregnancy and preeclampsia but were significantly higher in patients with preeclampsia. Preeclampsia was also found to be the best explanatory variable for the increase of sST2 levels in ethnic Malay predominance.

Heart-type fatty acid binding protein is related to severity and established cardiac biomarkers of heart failure

Objectives

To determine concentrations of heart-type fatty acid-binding protein (HFABP) in patients with heart failure with reduced ejection fraction (HFrEF) and its potential value for prognostic assessment.

Methods

Circulating levels of HFABP were measured with an automated chemiluminescent immunoassay in 25 healthy volunteers and 60 HFrEF patients.

Results

Concentrations of HFABP were significantly increased in heart failure patients in comparison to healthy volunteers. HFABP levels were significantly correlated to New York Heart Association classes and to established biomarkers of cardiac dysfunction and remodeling (amino-terminal pro-B-type natriuretic peptide [NT-proBNP], fibroblast growth factor 23, and galectin-3). HFABP concentrations were also predictive of cardiovascular (CV) death and combination with NT-proBNP might be synergistic for risk assessment.

Conclusions

HFABP levels are increased in HFrEF patients, related to adverse CV outcomes, and might assist physicians for patient's management.

Suppression of tumorigenicity 2 after exercise: a systematic review

Exercise is a pivotal physiological activity, associated with benefits. Whilst the importance of physical activity is consensual along different steps of the cardiovascular (CV) continuum, there has been interest in assessing the CV adaptations to vigorous exercise. Indeed, exercise can be associated with increases in cardiac biomarkers, though the scope of this observation remains elusive. Interleukin 1 receptor related protein, Suppression of tumorigenicity 2 (ST2) is a biomarker related to the pathophysiology of fibrosis, having shown promise in the study of heart failure. Knowledge of ST2 kinetics could improve understanding of the mechanistic pathways related to CV adaptations to exercise. To assess the current state-of-the-art concerning ST2 levels after exercise in healthy individuals. A systematic review was carried out on three databases (Pubmed, ISI Web of Science and Scopus), up to October 2020, using the queries "ST2" or "ST-2" + "exercise" or "running". A total of six studies were included in the review, encompassing 349 subjects (73% male gender) in which ST2 was assessed. Most studies reported increases in ST2 levels after exercise. Three studies, encompassing a total of 219 individuals, described a cut-off level of 35 ng/dL for ST2. In these, 92.7% of subjects had ST2 levels above this cut-off after exercise (running in all studies). Most studies report increased levels of ST2 after exercise, with an important number of individuals exceeding the 35 ng/dL threshold. Given the small number of individuals represented and the lack of imaging data and long-term follow-up, further prospective larger studies should target this.

The Role of Galectin-3 and ST2 in Cardiology: A Short Review

Galectin-3 is a lectin that binds beta-galactosides. It is involved in cardiac remodeling and fibrosis through the activation of macrophages and fibroblasts. ST2 is secreted by myocardial cells due to cardiac overload. These two biomarkers have been traditionally studied in the field of heart failure to guide medical therapy and detect the progression of the disease. Nevertheless, there are novel evidences that connect galectin-3 and ST2 with coronary heart disease and, specifically, with atrial fibrillation. The aim of this article is to concisely review the diagnostic and prognostic role of galectin-3 and ST2 in different cardiac diseases.

Predictive values of sST2 and IL-33 for heart failure in patients with acute myocardial infarction

Timely prediction of the risk of heart failure in acute myocardial infarction patients is critical for better prognosis. This article aims to evaluate the predictive value of serum soluble growth stimulation expressed gene 2 (sST2) and interleukin-33 in patients with acute myocardial infarction complicated by heart failure. A total of 42 healthy controls and 144 acute myocardial infarction patients were recruited in the study. According to Killip cardiac function classification as the basis for concurrent heart failure, they were distributed into non-heart failure group (n = 76) and heart failure group (n = 68). ELISA was utilized to determine the serum sST2 and interleukin-33 levels, and the diagnostic efficiency was evaluated by receiver operating characteristics curve. sST2 and interleukin-33 levels in patients with acute myocardial infarction were significantly increased when compared with normal healthy controls, and were further enhanced in the heart failure group. With the increased Killip cardiac function classification, interleukin-33 and sST2 levels were gradually elevated. Multivariate analysis indicated that interleukin-33 and sST2 could be used as independent predictors for heart failure combined with acute myocardial infarction.

Diagnostic Value of sST2 in Cardiovascular Diseases: A Systematic Review and Meta-Analysis

Biomarkers such as B-type natriuretic peptide (BNP), N-terminal pro-BNP (NT-proBNP), cardiac troponin (cTn), and CK-MB contribute significantly to the diagnosis of cardiovascular disease (CVD). Recent studies have demonstrated that suppression of tumorigenicity 2 (ST2) is associated with CVD, but a meta-analysis of ST2 levels in different CVDs has yet to be conducted. Therefore, the present study aimed to investigate soluble ST2 (sST2) levels in patients with ischemic heart disease (IHD), myocardial infarction (MI), and heart failure (HF). A total of 1,425 studies were searched across four databases, of which 16 studies were included in the meta-analysis. The Newcastle-Ottawa Quality Assessment Scale (NOS) values of all 16 studies were ≥7. The meta-analysis results indicated that the sST2 level was not correlated with IHD (standard mean difference [SMD] = 0.58, 95% confidence interval [95% CI] = 0.00 to 1.16, p = 0.05) or MI (weighted mean difference [WMD] = 0.17, 95% CI = -0.22 to 0.55, p = 0.40) but was significantly associated with HF (WMD = 0.21, 95% CI = 0.04 to 0.38, p = 0.02; I 2 = 99%, p < 0.00001). sST2 levels did not differ significantly between patients with IHD or MI and healthy individuals; however, we believe that ST2 could be used as an auxiliary diagnostic biomarker of HF.

The Diagnostic Value of Soluble ST2 in Heart Failure: A Meta-Analysis

Objective: The diagnostic performance of soluble suppression of tumorigenicity (sST2) in heart failure (HF) had been investigated in multiple studies, but the results were inconsistent. This meta-analysis evaluated the diagnostic value of sST2 in HF.

Methods: Pubmed, Web of Science, Embase, and Cochrane Library databases were searched until March 2021. Cohort studies or case-control studies relevant to the diagnostic value of sST2 in HF were screened, and true positive (TP), false positive (FP), false negative (FN), and true negative (TN) data were extracted for calculating sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC). The quality of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS), the threshold effect was determined by calculating Spearman correlation coefficients and summary receiver operating characteristic (SROC) curve patterns, the heterogeneity was evaluated using the I² statistic and the Galbraith radial plot, and sensitivity analysis was also performed. Deeks' test was used to assess publication bias.

Results: A total of 11 studies from 10 articles were included in this meta-analysis. The Spearman correlation coefficient was 0.114, p = 0.739, and the SROC curve did not show a “shoulder-arm” shape, which suggests that there was no threshold effect, but study heterogeneity existed because of non-threshold effects. The combined sensitivity was 0.72 [95% confidence interval (CI): 0.65–0.78], specificity was 0.65 (95% CI: 0.45–0.81), PLR was 1.75 (95% CI: 1.33–2.31), NLR was 0.48 (95% CI: 0.37–0.63), DOR was 3.63 (95% CI: 2.29–5.74), and AUC was 0.75. The Deeks' test suggested no significant publication bias in the included studies (P = 0.94).

Conclusion: sST has some diagnostic value in HF, but this should be further evaluated in additional studies with rigorous design and high homogeneity.

Soluble form of suppression of tumorigenicity-2 predicts clinical stability of inpatients with community-acquired pneumonia

The soluble form of the suppression of tumorigenicity-2 (sST2) is a biomarker for risk classification and prognosis of heart failure, and its production and secretion in the alveolar epithelium are significantly correlated with the inflammation-inducing in pulmonary diseases. However, the predictive value of sST2 in pulmonary disease had not been widely studied. This study investigated the potential value in prognosis and risk classification of sST2 in patients with community-acquired pneumonia. Clinical data of ninety-three CAP inpatients were retrieved and their sST2 and other clinical indices were studied. Cox regression models were constructed to probe the sST2's predictive value for patients' restoring clinical stability and its additive effect on pneumonia severity index and CURB-65 scores. Patients who did not reach clinical stability within the defined time (30 days from hospitalization) have had significantly higher levels of sST2 at admission (P < 0.05). In univariate and multivariate Cox regression analysis, a high sST2 level (≥72.8 ng/mL) was an independent reverse predictor of clinical stability (P < 0.05). The Cox regression model combined with sST2 and CURB-65 (AUC: 0.96) provided a more accurate risk classification than CURB-65 (AUC:0.89) alone (NRI: 1.18, IDI: 0.16, P < 0.05). The Cox regression model combined with sST2 and pneumonia severity index (AUC: 0.96) also provided a more accurate risk classification than pneumonia severity index (AUC:0.93) alone (NRI: 0.06; IDI: 0.06, P < 0.05). sST2 at admission can be used as an independent early prognostic indicator for CAP patients. Moreover, it can improve the predictive power of CURB-65 and pneumonia severity index score.

The Janus Face of IL-33 Signaling in Tumor Development and Immune Escape

Simple Summary

Interleukin-33 (IL-33) is often released from damaged cells, acting as a danger signal. IL-33 exerts its function by interacting with its receptor suppression of tumorigenicity 2 (ST2) that is constitutively expressed on most immune cells. Therefore, IL-33/ST2 signaling can modulate immune responses to participate actively in a variety of pathological conditions, such as cancer. Like a two-faced Janus, which faces opposite directions, IL-33/ST2 signaling may play contradictory roles on its impact on cancer progression through both immune and nonimmune cellular components. Accumulating evidence demonstrates both pro- and anti-tumorigenic properties of IL-33, depending on the complex nature of different tumor immune microenvironments. We summarize and discuss the most recent studies on the contradictory effects of IL-33 on cancer progression and treatment, with a goal to better understanding the various ways for IL-33 as a therapeutic target.

Abstract

Interleukin-33 (IL-33), a member of the IL-1 cytokine family, plays a critical role in maintaining tissue homeostasis as well as pathological conditions, such as allergy, infectious disease, and cancer, by promoting type 1 and 2 immune responses. Through its specific receptor ST2, IL-33 exerts multifaceted functions through the activation of diverse intracellular signaling pathways. ST2 is expressed in different types of immune cells, including Th2 cells, Th1 cells, CD8⁺ T cells, regulatory T cells (T_reg), cytotoxic NK cells, group 2 innate lymphoid cells (ILC2s), and myeloid cells. During cancer initiation and progression, the aberrant regulation of the IL-33/ST2 axis in the tumor microenvironment (TME) extrinsically and intrinsically mediates immune editing via modulation of both innate and adaptive immune cell components. The summarized results in this review suggest that IL-33 exerts dual-functioning, pro- as well as anti-tumorigenic effects depending on the tumor type, expression levels, cellular context, and cytokine milieu. A better understanding of the distinct roles of IL-33 in epithelial, stromal, and immune cell compartments will benefit the development of a targeting strategy for this IL-33/ST2 axis for cancer immunotherapy.

Cardiac Biomarkers in hypertensive disorders of pregnancy

In recent years, biomarkers have taken a central place in the assessment of cardiovascular diseases – from prediction to management and prognosis. On the other hand, enough evidence exists to assume that hypertensive disorders of pregnancy share a certain connection with cardiovascular diseases – from common risk factors and underlying mechanisms to the presence of a higher risk for women for the development of a great number of cardiovascular diseases, such as arterial hypertension, coronary atherosclerosis, stroke, peripheral artery disease, venous thromboembolism, and even a higher cardiovascular mortality. The key to a better understanding of the unfavorable cardiovascular profile of women with a hypertensive disorder of pregnancy may lie in their assessment with biomarkers, typically used in the field of cardiology. In this review, we have included studies investigating the use of cardiovascular biomarkers during or after a hypertensive pregnancy, namely, natriuretic peptides, high-sensitivity cardiac troponins, growth/differentiation factor 15 (GDF15), soluble suppression of tumorigenicity-2 (sST2), and galectin-3.

A possible role for ST2 as prognostic biomarker for COVID-19

COVID-19 is a pandemic illness caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2). It has been estimated that 80% of subject infected are asymptomatic or have mild to moderate symptoms. Differently, in severe cases of COVID-19, cytokine storm, acute respiratory distress syndrome (ARDS), severe systemic inflammatory response and cardiovascular diseases were observed Even if all molecular mechanisms leading to cardiovascular dysfunction in COVID-19 patients remain to be clarified, the evaluation of biomarkers of cardiac injury, stress and inflammation proved to be an excellent tool to identify the COVID-19 patients with worse outcome. However, the number of biomarkers used to manage COVID-19 patients is expected to increase with the increasing knowledge of the pathophysiology of the disease. It is our view that soluble suppressor of tumorigenicity 2 (sST2) can be used as biomarker in COVID-19. sST2 is routinely used as prognostic biomarker in patients with HF. Moreover, high circulating levels of sST2 have also been found in subjects with ARDS, pulmonary fibrosis and sepsis. Keeping in mind these considerations, in this review the possible mechanisms through which the SARS-CoV2 infection could damage the cardiovascular system were summarized and the possible role of sST2 in COVID-19 patients with CVD was discussed.

Prognostic Value of Soluble Suppression of Tumorigenicity 2 in Chronic Kidney Disease Patients: A Meta-Analysis

Objective

Previous studies have controversial results about the prognostic role of soluble suppression of tumorigenicity 2 (sST2) in chronic kidney disease (CKD). Therefore, we conduct this meta-analysis to access the association between sST2 and all-cause mortality, cardiovascular disease (CVD) mortality, and CVD events in patients with CKD.

Methods

The publication studies on the association of sST2 with all-cause mortality, CVD mortality, and CVD events from PubMed and Embase were searched through August 2020. We pooled the hazard ratio (HR) comparing high versus low levels of sST2 and subgroup analysis based on treatment, continent, and diabetes mellitus (DM) proportion, and sample size was also performed.

Results

There were 15 eligible studies with 11,063 CKD patients that were included in our meta-analysis. Elevated level of sST2 was associated with increased risk of all-cause mortality (HR 2.05; 95% confidence interval (CI), 1.51-2.78), CVD mortality (HR 1.68; 95% CI, 1.35-2.09), total CVD events (HR 1.88; 95% CI, 1.26-2.80), and HF (HR 1.35; 95% CI, 1.11-1.64). Subgroup analysis based on continent, DM percentage, and sample size showed that these factors did not influence the prognostic role of sST2 levels to all-cause mortality.

Conclusions

Our results show that high levels of sST2 could predict the all-cause mortality, CVD mortality, and CVD events in CKD patients.

Development of a Novel Homogeneous Nanoparticle-Based Assay for Rapid and High-Throughput Quantitation of the sST2 Protein in Human Serum

Purpose

The suppression of tumorigenicity 2 (ST2) protein is a member of the interleukin-1 receptor family with the transmembrane (ST2L) and soluble (sST2) subtypes and plays an important role in several diseases. Therefore, the present study aimed to establish and validate a novel amplified luminescent proximity homogeneous immunoassay (AlphaLISA) for the detection of sST2 in human serum.

Materials and Methods

Based on a sandwich-type immunoassay format, sST2 was captured using two different anti-sST2 antibodies. One of the antibodies was biotinylated while the other one was coated with AlphaLISA chemibeads. Thereafter, multiple tests were conducted to optimize the working conditions and validate analytical performance.

Results

The optimum concentration of the biotinylated antibodies was 1 μg/mL while the optimal dilution ratio for the anti-sST2 antibodies and conjugated chemibeads was 1:500. In addition, the optimal antigen-antibody reaction time was 15 minutes (min). Notably, the developed method showed a short turnaround time of about 25 min. Moreover, the assay exhibited high sensitivity with a limit of detection (LOD) of 0.176 ng/mL and a limit of quantification (LOQ) of 0.8 ng/mL. Furthermore, the intra-assay precision and inter-assay precision values were 5.29–7.10% and 9.41%–13.66%, respectively. It is also noteworthy that the test results deviated by less than ±10% when samples had ≤10.0 ng/mL of triglycerides, ≤0.5 mmol/L of bilirubin, ≤5.0 g/L of triglyceride, and ≤250 μg/L of biotin. Additionally, the developed assay was almost consistent with the commercially available PresageTM ST2 assay kit, with a Spearman correlation coefficient of 0.916 and an R² of 0.963 as well as a slope of 0.957 from linear regression analysis.

Conclusion

The present study showed that the sandwich AlphaLISA is a rapid, high-throughput, and reliable test for studying the levels of sST2 in a variety of diseases.

The Extracellular Bone Marrow Microenvironment-A Proteomic Comparison of Constitutive Protein Release by In Vitro Cultured Osteoblasts and Mesenchymal Stem Cells

Simple Summary

Normal blood cells are formed in the bone marrow by a process called hematopoiesis. This process is supported by a network of non-hematopoietic cells including connective tissue cells, blood vessel cells and bone-forming cells. However, these cells can also support the growth of cancer cells, i.e., hematological malignancies (e.g., leukemias) and cancers that arise in another organ and spread to the bone marrow. Two of these cancer-supporting normal cells are bone-forming osteoblasts and a subset of connective tissue cells called mesenchymal stem cells. One mechanism for their cancer support is the release of proteins that support cancer cell proliferation and progression of the cancer disease. Our present study shows that both these normal cells release a wide range of proteins that support cancer cells, and inhibition of this protein-mediated cancer support may become a new strategy for cancer treatment.

Abstract

Mesenchymal stem cells (MSCs) and osteoblasts are bone marrow stromal cells that contribute to the formation of stem cell niches and support normal hematopoiesis, leukemogenesis and development of metastases from distant cancers. This support is mediated through cell–cell contact, release of soluble mediators and formation of extracellular matrix. By using a proteomic approach, we characterized the protein release by in vitro cultured human MSCs (10 donors) and osteoblasts (nine donors). We identified 1379 molecules released by these cells, including 340 proteins belonging to the GO-term Extracellular matrix. Both cell types released a wide range of functionally heterogeneous proteins including extracellular matrix molecules (especially collagens), several enzymes and especially proteases, cytokines and soluble adhesion molecules, but also several intracellular molecules including chaperones, cytoplasmic mediators, histones and non-histone nuclear molecules. The levels of most proteins did not differ between MSCs and osteoblasts, but 82 proteins were more abundant for MSC (especially extracellular matrix proteins and proteases) and 36 proteins more abundant for osteoblasts. Finally, a large number of exosomal proteins were identified. To conclude, MSCs and osteoblasts show extracellular release of a wide range of functionally diverse proteins, including several extracellular matrix molecules known to support cancer progression (e.g., metastases from distant tumors, increased relapse risk for hematological malignancies), and the large number of identified exosomal proteins suggests that exocytosis is an important mechanism of protein release.

Anti-Tumorigenic Activities of IL-33: A Mechanistic Insight

Interleukin-33 (IL-33) is an epithelial-derived cytokine that can be released upon tissue damage, stress, or infection, acting as an alarmin for the immune system. IL-33 has long been studied in the context of Th2-related immunopathologies, such as allergic diseases and parasitic infections. However, its capacity to stimulate also Th1-type of immune responses is now well established. IL-33 binds to its specific receptor ST2 expressed by most immune cell populations, modulating a variety of responses. In cancer immunity, IL-33 can display both pro-tumoral and anti-tumoral functions, depending on the specific microenvironment. Recent findings indicate that IL-33 can effectively stimulate immune effector cells (NK and CD8⁺ T cells), eosinophils, basophils and type 2 innate lymphoid cells (ILC2) promoting direct and indirect anti-tumoral activities. In this review, we summarize the most recent advances on anti-tumor immune mechanisms operated by IL-33, including the modulation of immune checkpoint molecules, with the aim to understand its potential as a therapeutic target in cancer.

Cells in Cardiovascular Disease: Using Diversity to Confront Adversity

The present Special Issue on "Cells in Cardiovascular Disease" wants to offer a general overview of current cardiovascular research and illustrate how advances in the molecular characterization at the cellular level are providing unique insights into pathologies of the circulatory system [...].