Circadian variations of interleukin 6 in coronary circulations of patients with myocardial infarction

Relationship between serum interleukin-6 levels and severity of coronary artery disease undergoing percutaneous coronary intervention

BACKGROUND

Cytokines play a potential role in atherosclerosis pathogenesis and progression. We investigated the association of interleukin-6 (IL-6) with the angiographic severity of coronary artery disease (CAD).

METHODS

Three hundred ten angiografically diagnosed CAD patients and 210 controls were enrolled in this study. CAD patients were stratified according to IL-6 cut-off value into high levels IL-6 group (≥ 9.5 pg/mL) and low levels IL-6 group (< 9.5 pg/mL). The severity of CAD was assessed according to Gensini score (GS), artery stenosis degree and the number of vessels involved. The mean age was 60.3 ± 11.0 years.

RESULTS

The level of IL-6 in patients was increased compared to controls and ranged from 1.5 to 3640.0 pg/mL. High levels of IL-6 were significantly associated with high levels of GS (> 40) but not with stenosis degree and vessel score. GS levels were significantly more elevated in patients with high levels of IL-6 group than in low IL6 levels patients (60.6 ± 39.5 vs 46.7 ± 37.2; p = 0.027). The analysis of the ROC curve performed in myocardial infarction patients showed that IL-6 (AUC: 0.941 (CI 95% 0.886, 0.997; p < 0.001) could be a powerful predictor marker in evaluating the infarct size after myocardial infarction when compared to myonecrosis biomarkers.

CONCLUSIONS

IL-6 levels were associated with the severity of CAD assessed by the GS. Based on the highest levels of IL-6 measured in patients with STEMI, our study strongly suggests that IL-6 could be a powerful marker in evaluating the myocardial necrosis.

TRIAL REGISTRATION

ClinicalTrials.gov Number: NCT03075566 (09/03/2017).

Trans-Myocardial Blood Interleukin-6 Levels Relate to Intracoronary Imaging-Defined Features of Plaque Vulnerability and Predict Procedure-Induced Myocardial Infarction

BACKGROUND

Intravascular imaging has defined various vulnerable plaque (VP) phenotypes that predict future clinical events. Atherosclerosis is an inflammatory process and inflammation, measured by systemic biomarkers can also predict events and anti-inflammatory therapy is beneficial. We were interested to assess the relationship between plaque phenotypes and key inflammatory biomarkers, measured close to the coronary.

METHODS

Ninety-two patients scheduled for elective percutaneous coronary intervention (PCI) underwent virtual histology intravascular ultrasound, optical coherence tomography, pressure wire and blood sampling from the guide catheter (GC), coronary sinus (CS) to determine trans-myocardial gradient (TMG = CS-GC) and from peripheral blood. Procedure related troponin release was assessed at 6-hours post-PCI from peripheral venous blood. Biomarker data were analysed and compared with coronary data.

RESULTS

Interleukin (IL)-6 was associated with increased levels of tumour necrosis factor (TNF)-α and C-reactive protein (CRP) and the pre-PCI IL-6 TMG correlated with plaque features of vulnerability: plaque burden - PB (r = 0.253, p = 0.04) and minimal lumen area - MLA (r = -0.438, p = 0.007), although no relationship existed for thin-capped fibroatheroma defined by either imaging modality. Peripheral IL-6 levels had no correlation with post PCI troponin, although the pre-PCI IL-6 TMG was related (r = 0.334, p = 0.006), as was PB (r = 0.27, p = 0.029).

CONCLUSION

IL-6 TMG pre-PCI correlates with plaque burden and MLA that have been shown to predict future clinical events and is correlated with post-PCI troponin release. These associations were not apparent from peripheral blood and suggest that local coronary biomarker signatures may help further define vulnerability and risk.

Characteristics of Interleukin-6 Signaling in Elective Cardiac Surgery—A Prospective Cohort Study

Interleukin-6 (IL-6) can cause pro- and anti-inflammatory effects via different signaling pathways. This prospective study investigated the perioperative kinetics of IL-6, soluble IL-6 receptor (sIL-6R), and soluble glycoprotein 130 (sgp130) in elective patients undergoing cardiopulmonary bypass (CPB). IL-6, sIL-6R, and sgp130 were measured simultaneously and consecutively at 19 timepoints until the 10th postoperative day (POD). The proportion of pro- and anti-inflammatory pathways were determined by calculating sIL-6R/IL-6 and sIL-6R/sgp130 ratios. We analyzed 93 patients. IL-6 increased during surgery with reaching a plateau two hours after CPB and peaking on POD 1 (188.5 pg mL⁻¹ (IQR, 126.6; 309.2)). sIL-6R decreased at the beginning of the surgical procedure, reaching a nadir level on POD 2 (26,311 pg mL⁻¹ (IQR, 22,222; 33,606)). sgp130 dropped immediately after CPB initiation (0.13 ng mL⁻¹ (IQR, 0.12; 0.15)), followed by a continuous recovery until POD10. The sIL-6R/IL-6 ratio decreased substantially at the beginning of the procedure, reaching a nadir on POD 1 (149.7 (IQR, 82.4; 237.4)), while the sIL-6R/sgp130 ratio increased simultaneously until 6 h post CPB (0.219 (IQR 0.18; 0.27)). In conclusion, IL-6 exhibited high inter-individual variability reflecting an inhomogeneous inflammatory response. Pro-inflammatory effects and overwhelming inflammation were rare and predominantly anti-inflammatory effects were found.

The Inflammasome Signaling Pathway Is Actively Regulated and Related to Myocardial Damage in Coronary Thrombi from Patients with STEMI

Background

The Nod-Like-Receptor-Protein-3 (NLRP3) inflammasome and the Interleukin-6 (IL-6) pathways are central mechanisms of the inflammatory response in myocardial reperfusion injury. Expanding our knowledge about the inflammasome signaling axis is important to improve treatment options. In a cross-sectional study, we aimed to study presence, localization, and genetic expression of inflammasome- and IL-6- signaling-related proteins in coronary thrombi and circulating leukocytes from ST-elevation myocardial infarction (STEMI) patients, with relation to myocardial injury and time from symptoms to PCI.

Methods

Intracoronary thrombi were aspirated from 33 STEMI patients. Blood samples were drawn. mRNA of Toll-Like-Receptor-4 (TLR4), NLRP3, caspase 1, Interleukin-1β (IL1-β), Interleukin-18 (IL-18), IL-6, IL-6-receptor (IL-6R), and glycoprotein 130 (gp130) were isolated from thrombi and circulating leukocytes and relatively quantified by RT-PCR. A part of each thrombus was embedded in paraffin for histology and immunohistochemistry analyses.

Results

Genes encoding the 8 markers were present in 76-100% of thrombi. Expression of TLR4 in thrombi significantly correlated to troponin T (r = 0.455, p = 0.013), as did NLRP3 (r = 0.468, p = 0.024). Troponin T correlated with expression in circulating leukocytes of TLR4 (r = 0.438, p = 0.011), NLRP3 (r = 0.420, p = 0.0149), and IL-1β (r = 0.394, p = 0.023). IL-6R expression in thrombi correlated significantly to troponin T (r = 0.434, p = 0.019), whereas gp130 was inversely correlated (r = −0.398, p = 0.050). IL-6 in circulating leukocytes correlated inversely to troponin T (r = −0.421, p = 0.015). There were no significant correlations between genes expressed in thrombi and time from symptom to PCI.

Conclusions

The inflammasome signaling pathway was actively regulated in coronary thrombi and in circulating leukocytes from patients with STEMI, in association with myocardial damage measured by troponin T. This supports the strategy of medically targeting this pathway in treating myocardial infarction and contributes to sort out optimal timing and targets for anti-inflammatory treatment. The study is registered at clinicaltrials.gov with identification number NCT02746822.

Alterations of soluble TWEAK and CD163 concentrations in patients with chronic heart failure

Inflammatory activation plays a pivotal role in chronic heart failure with reduced ejection fraction (HF-REF). A novel mediator from TNF family: soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) along its soluble decoy receptor CD163 (sCD163) recently has been investigated in other cardiovascular pathologies. We aimed to evaluate sTWEAK and sCD163 concentrations in HF-REF patients. The study enrolled 79 patients with stable HF-REF, EF < 35%. The control population without history of heart failure included two groups: 26 comorbidities matched patients and 27 healthy volunteers. sTWEAK and sCD163 serum concentrations were determined using ELISA kits. Univariate and multivariate analysis was performed to assess variables affecting concentration of sTWEAK and sCD163. HF-REF patients were characterized by higher sTWEAK (median 374 IQR: 321-429 vs 201 IQR: 145-412pg/ml, P=0.005), sCD163 (median 744 IQR: 570-1068 vs 584 IQR: 483-665pg/ml, P=0.03) concentrations and sTWEAK/sCD163 ratio (median 0.53 IQR: 0.32-0.7 vs 0.3 IQR: 0.22-0.37, P=0.001) comparing to healthy volunteers. Comparing to comorbidities matched controls, HF-REF patients had lower sTWEAK levels (median 374 IQR: 321-429 vs 524 IQR: 384-652pg/ml; P=0.002), while sCD163 and sTWEAK/sCD163 ratio didn't differ. Concentration of sTWEAK in HF-REF was affected by white blood cell count and aspirin intake, while sCD163 by exercise capacity, LV diastolic volume, CRP and presence of arterial hypertension.

CONCLUSIONS

HF-REF patients present increased sTWEAK and sCD163 levels as well as sTWEAK/sCD163 ratio when compared to healthy subjects, however CHF itself appears to be associated with down-regulation of sTWEAK.

IL-6 signalling in patients with acute ST-elevation myocardial infarction

Cytokines of the IL-6 family have been related to infarct size and prognosis in patients with myocardial infarction. The aims of the present study were to elucidate possible associations between myocardial necrosis and left ventricular impairment and members of the IL-6 transsignalling system including soluble (s) IL-6R and (s) glycoprotein 130 (sgp130) in patients with ST-elevation myocardial infarction (STEMI) treated with primary PCI. In blood samples from 1028 STEMI patients, collected in-hosptial, we found significant correlations between peak TnT and IL-6 and CRP (p < 0.001, all) and between IL-6 and CRP and LV ejection fraction and NT-proBNP (p < 0.001, all). On the contrary, no significant associations were found between peak TnT and sgp130 or sIL-6R. Furthermore sgp130 was significantly elevated in diabetic patients and also associated with the glucometabolic state. In conclusion, circulating levels of IL-6 and CRP, but not the soluble forms of the receptor (sIL-6R) or the receptor signalling subunit (sgp130) were associated with the extent of myocardial necrosis. The biological importance of the IL-6/gp130-mediated signalling pathways in patients with acute myocardial infarction and dysglycemia should be further elucidated.

Stress management skills, neuroimmune processes and fatigue levels in persons with chronic fatigue syndrome

OBJECTIVES

Stressors and emotional distress responses impact chronic fatigue syndrome (CFS) symptoms, including fatigue. Having better stress management skills might mitigate fatigue by decreasing emotional distress. Because CFS patients comprise a heterogeneous population, we hypothesized that the role of stress management skills in decreasing fatigue may be most pronounced in the subgroup manifesting the greatest neuroimmune dysfunction.

METHODS

In total, 117 individuals with CFS provided blood and saliva samples, and self-report measures of emotional distress, perceived stress management skills (PSMS), and fatigue. Plasma interleukin-1-beta (IL-1β, IL-2, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α), and diurnal salivary cortisol were analyzed. We examined relations among PSMS, emotional distress, and fatigue in CFS patients who did and did not evidence neuroimmune abnormalities.

RESULTS

Having greater PSMS related to less fatigue (p=.019) and emotional distress (p<.001), greater diurnal cortisol slope (p=.023) and lower IL-2 levels (p=.043). PSMS and emotional distress related to fatigue levels most strongly in CFS patients in the top tercile of IL-6, and emotional distress mediated the relationship between PSMS and fatigue most strongly in patients with the greatest circulating levels of IL-6 and a greater inflammatory (IL-6):anti-inflammatory (IL-10) cytokine ratio.

DISCUSSION

CFS patients having greater PSMS show less emotional distress and fatigue, and the influence of stress management skills on distress and fatigue appear greatest among patients who have elevated IL-6 levels. These findings support the need for research examining the impact of stress management interventions in subgroups of CFS patients showing neuroimmune dysfunction.

The G to A polymorphism at -597 of the interleukin-6 gene is extremely rare in southern Han Chinese

Interleukin-6 (IL-6) is a cytokine involved in different physiologic and pathophysiologic processes including essential hypertension (EH). Associations of the IL-6 promoter region polymorphisms with circulating level of IL-6 have been reported in various studies. We detected the IL-6-597G/A polymorphism in 246 EH patients and 194 healthy controls from Jiangsu area (south of China). Individuals all carried the GG wild genotype, no GA or AA genotypes were found. Our results suggest that IL-6-597G/A polymorphism is extremely rare and unlikely to be contributing significantly to disease susceptibility in southern Han Chinese.