Elevated circulating sST2 associated with subclinical atherosclerosis in newly diagnosed primary hypertension

Is there a relationship between heart rate recovery and blood pressure in white coat hypertension?

Aim    Increasing evidence suggests that autonomic dysfunction may be involved in the etiology of white coat hypertension (WCH). The aim of this study was to evaluate cardiac autonomic function by using heart rate recovery (HRR) indices in patients with WCH classified according to their circadian rhythm type of blood pressure (BP).Material and methods    This cross-sectional study included 120 participants over the age of 18 yrs, including 50 patients diagnosed with WCH and 70 healthy controls with normal in- and out-of-office BP and without any known disease. Circadian rhythm types, i.e., dippers and non-dippers, were identified using ambulatory BP monitoring. The HRR indices were calculated by subtracting the 1st-minute (HRR1), 2nd-minute (HRR2), and 3rd-minute (HRR3) heart rates from the maximal heart rate recorded during stress testing.Results    The lesser decline in nighttime BP (6.4±2.14 and 13.3±2.2 mmHg, respectively; p<0.001) and the smaller mean HRR1 (25.5±3.0 and 30.3±3.1 beats / min, respectively; p<0.001) were evident in WCH non-dippers compared to WCH dippers. Linear regression analysis showed that HRR1 (β±SE=0.43±0.11; p<0.001) and diastolic BP at maximum exercise (β±SE=0.14±0.07; p=0.040) are independent risk factors for the blunted decline in nighttime BP.Conclusion    Delayed recovery of heart rate after an exercise stress test is associated with non-dipper type of circadian rhythm of BP. This was more pronounced in WCH patients, and these patients are at risk of autonomic dysfunction.

Serum soluble ST2 is a potential long-term prognostic biomarker for transient ischaemic attack and ischaemic stroke

BACKGROUND AND PURPOSE

Soluble ST2 (sST2) is a promising biomarker in inflammation, atherosclerosis and cardiovascular diseases. We investigated the association between serum sST2 and poor outcome in patients with transient ischaemic attack (TIA)/ischaemic stroke.

METHODS

Patients within 24 h after onset and with measured serum sST2 were prospectively enrolled in this study. Poor outcome was a combination of a new stroke event (ischaemic or haemorrhagic) and all-cause death within 90 days and 1 year. The associations of serum sST2 with poor outcome were analysed by Cox proportional hazards.

RESULTS

Among the 430 patients included, the median (interquartile range) sST2 was 17.72 (9.31-28.84) ng/mL. A total of 19 (4.4%) and 38 (8.8%) patients experienced poor outcome within 90 days and 1 year, respectively. Compared with the lowest sST2 tertile, hazard ratios (HRs) [95% confidence intervals (CI)] for the highest tertile were 5.14 (1.43-18.51) for poor outcome within 90 days and 3.00 (1.29-6.97) at 1 year after multivariate adjustments. Adding sST2 to a prediction model significantly improved risk stratification of poor outcome in TIA/ischaemic stroke, as observed by the continuous net reclassification improvement of 60.98% (95% CI, 15.37-106.6%, P = 0.009) and integrated discrimination improvement of 2.63% (95% CI, 0.08-5.18%, P = 0.043) at 90 days and the continuous net reclassification improvement of 41.68% (95% CI, 8.74-74.61%, P = 0.013) at 1 year.

CONCLUSIONS

Increased serum sST2 levels in TIA/ischaemic stroke were associated with increased risks of poor outcome within 90 days and 1 year, suggesting that serum sST2 may be a potential long-term prognostic biomarker for TIA/ischaemic stroke.

Correlation of plasma soluble suppression of tumorigenicity-2 level with the severity and stability of coronary atherosclerosis

BACKGROUND

Soluble growth stimulation expressed gene 2 (sST2) is the receptor of interleukin (IL)-33. We hypothesized the IL-33/ST2 pathway may be closely related to the progression of coronary atherosclerotic lesions.

METHODS

We analyzed 262 patients, including 63 with stable angina pectoris (SAP), 97 with acute coronary syndrome (ACS), and 102 control subjects. Plasma sST2 levels were determined using ELISA. Gensini scores were calculated. Patients with ACS and SAP were further divided according to the complexity of atherosclerotic lesions (simple/complex). Statistical analysis was performed on all data.

RESULTS

The plasma sST2 levels were significantly higher in patients with coronary artery disease (CAD) than in the control group, and were significantly higher in ACS patients with complex lesions than in those with simple lesions. There were no correlations between plasma sST2 level and both the number of culprit vessels and Gensini score. Multivariate stepwise regression analysis revealed that angiographically detected complex lesions were independently correlated with plasma sST2 level. Logistic regression analyses showed that sST2 was an independent factor of both CAD and the lesion type (simple/complex) of ACS. For the diagnosis of ACS and complex lesions, the area under the receiver operating characteristic curve of sST2 was 0.651.

CONCLUSIONS

The plasma sST2 level was not correlated with the stenosis severity of coronary atherosclerosis. A relationship between the plasma sST2 level and the morphology of complex lesions was found for the first time, especially in ACS patients. It may be a new marker for assessing the stability and complexity of atherosclerotic plaques.

Alteration of the IL-33-sST2 pathway in hypertensive patients and a mouse model

Inflammatory cells play an important role in the occurrence of hypertension. Recent studies have demonstrated that interleukin-33/suppression of tumorigenicity 2 (IL-33/ST2) signaling plays a critical role in the pathogenesis of several cardiovascular diseases. We aimed to evaluate the association of IL-33 and its receptor levels with the occurrence of hypertension in angiotensin II (Ang II)-infused mice using microarray analysis and validated our results in human specimens. Male wild-type mice were infused with Ang II (1500 ng/kg/min) for 1, 3 and 7 days. Patients with essential hypertension (EH) (n = 166) and healthy control subjects (n = 306) were enrolled. Levels of IL-33 and ST2 mRNAs in serum and peripheral blood mononuclear cells (PBMCs) were analyzed by Luminex assay or ELISA and qPCR analysis. We found that IL-33 expression was significantly increased in the aortas of mice receiving Ang II infusion compared with that of control mice. In contrast, the levels of IL-33 in serum and PBMCs were not significantly different between hypertensive patients and normal controls. However, the levels of soluble ST2 (sST2) in serum and PBMCs were markedly higher in hypertensive patients than in controls (P < 0.001 and P = 0.014, respectively). In addition, the ST2L level in PBMCs was also significantly decreased in hypertensive patients (P = 0.028). Further, logistic analysis showed that the odds ratios of having hypertension based on sST2 levels in serum and PBMCs were 9.714 and 2.244 (P = 0.013 and P = 0.024, respectively) compared with the control group. Above all, sST2 acted as a risk factor for the occurrence of hypertension and may be a promising novel predictive marker for EH.

Are soluble ST2 levels influenced by vitamin D and/or the seasons?

OBJECTIVE

Cardiovascular disease manifestation and several associated surrogate markers, such as vitamin D, have shown substantial seasonal variation. A promising cardiovascular biomarker, soluble ST2 (sST2), has not been investigated in this regard – we therefore determined if systemic levels of sST2 are affected by seasonality and/or vitamin D in order to investigate their clinical interrelation and usability.

DESIGN

sST2 levels were measured in two cohorts involving hypertensive patients at cardiovascular risk, the Styrian Vitamin D Hypertension Trial (study A; RCT design, 8 weeks 2800 IU cholecalciferol daily) and the Ludwigshafen Risk and Cardiovascular Health Study (LURIC; study B; cross-sectional design).

Conflicting vascular and metabolic impact of the IL-33/sST2 axis

Interleukin 33 (IL-33), which is expressed by several immune cell types, endothelial and epithelial cells, and fibroblasts, is a cytokine of the IL-1 family that acts both intra- and extracellularly to either enhance or resolve the inflammatory response. Intracellular IL-33 acts in the nucleus as a regulator of transcription. Once released from cells by mechanical stress, inflammatory cytokines, or necrosis, extracellular IL-33 is proteolytically processed to act in an autocrine/paracrine manner as an 'alarmin' on neighbouring or various immune cells expressing the ST2 receptor. Thus, IL-33 may serve an important role in tissue preservation and repair in response to injury; however, the actions of IL-33 are dampened by a soluble form of ST2 (sST2) that acts as a decoy receptor and is produced by endothelial and certain immune cells. Accumulating evidence supports the conclusion that sST2 is a biomarker of vascular health with diagnostic and/or prognostic value in various cardiovascular diseases, including coronary artery disease, myocardial infarction, atherosclerosis, giant-cell arteritis, acute aortic dissection, and ischaemic stroke, as well as obesity and diabetes. Although sST2 levels are positively associated with cardiovascular disease severity, the assumption that IL-33 is always beneficial is naïve. It is increasingly appreciated that the pathophysiological importance of IL-33 is highly dependent on cellular and temporal expression. Although IL-33 is atheroprotective and may prevent obesity and type 2 diabetes by regulating lipid metabolism, IL-33 appears to drive endothelial inflammation. Here, we review the current knowledge of the IL-33/ST2/sST2 signalling network and discuss its pathophysiological and translational implications in cardiovascular diseases.

Association of Endocan, Ischemia-Modified Albumin, and hsCRP Levels With Endothelial Dysfunction in Type 2 Diabetes Mellitus

We investigated the relationship of ischemia-modified albumin (IMA) and high-sensitivity C-reactive protein (hsCRP) levels with direct (endocan) and indirect (carotid intima–media thickness [cIMT] and 24 hours urine protein excretion) endothelial dysfunction indicators in type 2 diabetes mellitus (T2DM). Patients with T2DM (n = 88) and 88 healthy individuals were included in the study. The median endocan (475.15 vs 216.37 pg/mL; P < .001, respectively) and hsCRP (10.74 vs 3.11 mg/L; P < .001, respectively) and the mean IMA (0.64 ± 0.12 vs 0.51 ± 0.12 absorbance units; P < .001, respectively) levels were higher in participants with endothelial dysfunction compared to those without endothelial dysfunction in T2DM. The 24-hour urine protein excretion and cIMT levels had a positive correlation with hsCRP ( r = .357; P = .001 and r = .592; P < .001, respectively), IMA ( r = .519; P < .001 and r = .495; P < .001, respectively) and endocan ( r = .347; P = .001 and r = .583; P < .001, respectively) levels in the T2DM group. Stepwise multivariable logistic regression analysis, which included laboratory findings found to be associated with endothelial dysfunction, showed that endocan (odds ratio [OR] = 1.456; P = .004), hsCRP (OR = 1.298; P = .008), and IMA (OR = 2.270, P = .003) were independent risk factors. It was found that none of these markers were superior in terms of diagnostic discrimination for endothelial dysfunction. Endocan, IMA, and hsCRP levels were found to be associated with endothelial dysfunction in patients with T2DM.