Compelling Benefit of Soluble Suppression of Tumorigenicity-2 in Post-Myocardial Infarction Estimation of Risk: The Time Is Right for Its Routine Use in the Clinic

Growth stimulation expressed gene 2 (ST2): Clinical research and application in the cardiovascular related diseases

As an interleukin (IL)-1 receptor family member, scientists found that when circulating soluble growth stimulation expressed gene 2 (sST2) is low, its ligand, IL-33, will bind to ST2L to exert protective effects on various types of cells. On the other hand, competitive binding of IL-33 occurs when sST2 concentrations are increased, followed by a reduction in the amount available for cell protection. Based on this mechanism, the usage of sST2 is to identify the population of high-risk patients with cardiovascular disease. In recent years, the role of serum sST2 in the occurrence, diagnosis, prognosis, and treatment of cardiovascular diseases has been gradually accepted by doctors. This manuscript systemically reviews the biological functions and applications of sST2 in disease diagnosis and treatment, especially for cardiovascular diseases. In clinical testing, since IL-33 can negatively impact sST2 measurement accuracy, the properties of current assay kits have been summarized and discussed to provide a clear view of the clinical chemistry results. Although sST2 is a promising biomarker, there are few quantitative approaches available for clinical testing. In this context, a mass spectrometry (MS)-based approach might be an option, as this is a powerful analytical tool to distinguish structurally related molecules in the matrix and decrease false-positive results in clinical testing. Moreover, approaches developed based on MS would be an ideal way to further study sST2 standardization.

Altered mRNA Expression of Interleukin-1 Receptors in Myocardial Tissue of Patients with Left Ventricular Assist Device Support

Serum levels of cytokines interleukin 1 beta ( IL-1β) and interleukin 33 (IL-33) are highly abnormal in heart failure and remain elevated after mechanical circulatory support (MCS). However, local cytokine signaling induction remains elusive. Left (LV) and right ventricular (RV) myocardial tissue specimens of end-stage heart failure (HF) patients without (n = 24) and with MCS (n = 39; 594 ± 57 days) were analyzed for cytokine mRNA expression level of IL-1B, interleukin 1 receptor 1/2 (IL-1R1/2), interleukin 1 receptor-like 1 (IL-1RL1), IL-33 and interleukin-1 receptor accessory protein (IL-1RaP). MCS patients showed significantly elevated IL-1B expression levels (LV: 2.0 fold, p = 0.0058; RV: 3.3 fold, p < 0.0001). Moreover, IL-1R1, IL-1RaP and IL-33 expression levels strongly correlated with each other. IL-1RL1 and IL-1R2 expression levels were significantly higher in RV myocardial tissue (RV/LV ratio IL-1R2 HF: 4.400 ± 1.359; MCS: 4.657 ± 0.655; IL-1RL1 HF: 3.697 ± 0.876; MCS: 4.529 ± 0.5839). In addition, IL1-RaP and IL-33 RV expression levels were significantly elevated in MCS. Furthermore, IL-33 expression correlates with C-reactive protein (CRP) plasma levels in HF, but not in MCS patients. Increased expression of IL-1B and altered correlation patterns of IL-1 receptors indicate enhanced IL-1β signaling in MCS patients. Correlation of IL-1 receptor expression with IL-33 may hint towards a link between both pathways. Moreover, diverging expression in LV and RV suggests specific regulation of local cytokine signaling.

Early sST2 Liberation after Implantation of a Left Ventricular Assist Device in Patients with Advanced Heart Failure

Background

The use of left ventricular assist device (LVAD) has increased considerably over the past decade; however, there is limited literature to assist in patient selection and monitoring. The frequency of adverse events remains high. We examined the early expression of circulating soluble ST2 (sST2), a biomarker with immunosuppressive and profibrotic activity, and assessed the risk of death at 1 year in patients receiving LVAD implant.

Methods

We prospectively enrolled 20 heart failure patients and measured sST2, IL-33, and IL-6 serum concentrations over three weeks after LVAD implantation. We compared the kinetics of IL-6, sST2, and IL-33 release in survivors with those of nonsurvivors using mixed model two-way analysis of variance for repeated measures. We also collected data on hemodynamic parameters (i.e., cardiac output) and frequency of infections during the hospital stay.

Results

LVAD therapy led to an immediate and significant improvement of the hemodynamic parameters in 1-year survivors and nonsurvivors alike. The 1-year survival rate was 65%. IL-6 concentrations showed a significant (p = 0.03) peak at admission to the intensive care unit following LVAD implantation, whereas sST2 levels were massively increased (p < 0.0003) on day 1. While 1-year survivors had persistently lower sST2 values compared to nonsurvivors during the first 3 weeks after LVAD implantation (p = 0.012), no differences were observed in the temporal pattern of IL-6 or IL-33. The odds of detecting Candida species in the bronchoalveolar lavage fluid were 14 times higher in nonsurvivors than in survivors (OR 13.7, CI 1.4-127, p = 0.02).

Conclusion

In patients implanted with LVAD, circulating sST2 levels and frequency of Candida colonisation were associated with higher mortality. Awareness of this early immune response can guide physicians in risk-benefit analysis.

Metal-induced bacterial interactions promote diversity in river-sediment microbiomes

Anthropogenic metal contamination results in long-term environmental selective pressure with unclear impacts on bacterial communities, which comprise key players in ecosystem functioning. Since metal contamination poses serious toxicity and bioaccumulation issues, assessing their impact on environmental microbiomes is important to respond to current environmental and health issues. Despite elevated metal concentrations, the river sedimentary microbiome near the MetalEurop foundry (France) shows unexpected higher diversity compared with the upstream control site. In this work, a follow-up of the microbial community assembly during a metal contamination event was performed in microcosms with periodic renewal of the supernatant river water. Sediments of the control site were gradually exposed to a mixture of metals (Cd, Cu, Pb and Zn) in order to reach similar concentrations to MetalEurop sediments. Illumina sequencing of 16S rRNA gene amplicons was performed. Metal-resistant genes, czcA and pbrA, as well as IncP plasmid content, were assessed by quantitative PCR. The outcomes of this study support previous in situ observations showing that metals act as community assembly managers, increasing diversity. This work revealed progressive adaptation of the sediment microbiome through the selection of different metal-resistant mechanisms and cross-species interactions involving public good-providing bacteria co-occurring with the rest of the community.

Predicting long-term cardiovascular outcomes of patients with acute myocardial infarction using soluble ST2

Background The increase in soluble suppression of tumorigenicity 2 (sST2) both in the diagnosis and prognosis of heart failure is well established; however, existing data regarding sST2 values as the prognostic marker after myocardial infarction (MI) are limited and have been conflicting. This study aimed to assess the clinical significance of sST2 in predicting 1-year adverse cardiovascular (CV) events in MI patients. Materials and methods In this prospective study, 380 MI patients were included. Participants were grouped into low sST2 (n = 264, mean age: 60.0 ± 12.1 years) and high sST2 groups (n = 116, mean age: 60.5 ± 11.6 years), and all study populations were followed up for major adverse cardiovascular events (MACE) which are composed of CV mortality, target vessel revascularization (TVR), non-fatal reinfarction, stroke and heart failure. Results During a 12-month follow-up, 68 (17.8%) patients had MACE. CV mortality and heart failure were significantly higher in the high sST2 group compared to the low sST2 group (15.5% vs. 4.9%, p = 0.001 and 8.6% vs. 3.4% p = 0.032, respectively). Multivariate Cox regression analysis concluded that high serum sST2 independently predicted 1-year CV mortality [hazard ratio (HR) 2.263, 95% confidence interval (CI) 1.124-4.557, p = 0.022)]. Besides, older age, Killip class >1, left anterior descending (LAD) as the culprit artery and lower systolic blood pressure were the other independent risk factors for 1-year CV mortality. Conclusions High sST2 levels are an important predictor of MACE, including CV mortality and heart failure in a 1-year follow-up period in MI patients.

Soluble ST2 for Prediction of Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction Receiving Primary PCI

Soluble suppression of tumorigenicity 2 (sST2), a biomarker representing myocardial fibrosis and inflammation, has been applied in risk stratification of patients with myocardial infarction (MI). However, whether primary PCI (PPCI) will eliminate the predictive value of sST2 in STEMI patients has not been well studied. Here, we conducted a prospective clinical trial to evaluate the correlation between sST2 and prognosis in STEMI patients undergoing PPCI. sST2 levels were measured in 295 STEMI patients (60.2 ± 10.8 years) at admission using a high sensitivity assay. Baseline sST2 levels were significantly associated with heart function, biomarkers of inflammation, and myocardial injury. During a 12-month follow-up, 19 patients had major adverse cardiovascular events (MACEs). Greater sST2 was continuously associated with a higher risk of incident MACEs. Such association remained even after adjusting for other risk factors in a multivariate Cox analysis. A baseline sST2 level in the highest quartile (≥ 58.7 ng/mL) was independently associated with mortality (HR: 5.01, 95%CI: 1.02-16.30, P = 0.048). More incident heart failure was seen in the group with greater sST2, however, the association was not significant after adjustment. Therefore, baseline sST2 may be useful to predict MACEs, especially mortality, in STEMI patients receiving PPCI.