In a large, heterogeneous cohort of HF patients, elevated IL-6 levels were found in more than 50% of patients and were associated with iron deficiency, reduced LVEF, atrial fibrillation and poorer clinical outcomes.
Cardiac myocyte injury and stress markers (troponin and natriuretic peptides), markers of renal function (glomeral filtration rate, cystatin-C), and inflammation markers/mediators (interleukin- 6, CRP) are promising biomarkers of patients with AF and MetS.
Our results demonstrated that pinocembrin treatment significantly decreased sympathetic activity, augmented parasympathetic activity, improved heart rate variability (HRV), prolonged the atrial effective refractory period (ERP) and action potential duration (APD), shortened activation latency (AL), lowered the indicibility rate of AF, attenuated atrial fibrosis, and decreased concentrations of norepinephrine (NE), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in the serum and the left atrial (LA).
The levels of myocardial fibrosis biomarkers, such as ST2 and Galectin-3, are elevated suggesting atrial structural abnormalities, while the increased levels of CRP and Interleukin-6 supplement the inflammatory profile of AF patients.
Our results demonstrate that AF development and progression (from paroxysmal to persistent) is associated with a gradual increase in serum levels of NT-proBNP, IL-6 and MMP-9/TIMP-1 ratio.
Polymorphisms in PITX2 (rs2200733) and IL6 (rs1800795) are associated with postoperative atrial fibrillation in adults but have not been studied in CHD.
High-sensitivity troponin T, growth differentiation factor-15, NT-proBNP (N-terminal pro-B-type natriuretic peptide), and interleukin-6 levels are predictive of cardiovascular events and total cardiovascular death in anticoagulated patients with atrial fibrillation.
The increased mRNA expressions of classic inflammatory factors (i.e., interleukin-1 beta, interleukin 6, and tumor necrosis factor-alpha) in AF(+)thrombus(+) group further validated the correlation between inflammation and thrombi in atrial fibrillation.
Using a novel proteomics approach, we confirmed the previously reported association between NT-pro-BNP, FGF-23, GDF-15 and incident AF, and also discovered four proteins (FABP4, IL-6, TIM-1 and AM) that could be of importance in the development of AF.
Its levels dropped significantly 1 week posttreatment only in AFib (P = 0.009 versus baseline); CRP and IL-6 remained practically stable throughout the study.
AF inducibility and duration were substantially increased in collagen-induced arthritis rats, and AF duration was significantly and positively correlated with the serum IL-6 and TNF-α levels.
Levels of circulating interleukin-6 and other proinflammatory molecules have consistently been associated with a risk for AF and its recurrence after catheter ablation.
These results suggest that IL-6-634C/G polymorphism is associated with thrombus and severe SEC, and the G allele is an independent risk for thrombus and severe SEC in Han Chinese patients with AF.
The Smad3 and IL-6 expressions in the in the LVEF <50% subgroup were both high that than that in LVEF ⩾ 50% group, and higher in the AF time ⩾ 36 months subgroup than that in <36 months subgroup (P<0.05).
Although a common, non-synonymous variant in the IL-6 receptor gene (IL6R rs2228145" genes_norm="3570">Asp358Ala; rs2228145 A>C) is associated with the risk of several common diseases, with the 358Ala allele conferring protection from coronary heart disease (CHD), rheumatoid arthritis (RA), atrial fibrillation (AF), abdominal aortic aneurysm (AAA), and increased susceptibility to asthma, the variant's effect on IL-6 signaling is not known.
The distribution of the IL-6-634C/G genotypes (CC, CG, and GG) was 67.02%, 30.85%, and 2.13% in the controls, and 50.67%, 40.00%, and 9.33% in AF subjects, respectively (P=0.0312).
This upregulated expression and activity were positively correlated with higher regulatory indicators of atrial structural remodeling as reflected by higher transcripts of tumor necrosis factor (TNF)-related apoptosis-inducing ligand, matrix metalloproteinase (MMP)-2 and MMP-9, pro-inflammatory factors TNF-α and interleukin-6, and higher ratios of MMP-9/tissue inhibitor of metalloproteinase (TIMP)-1 and MMP-2/TIMP-2 in AF.
Intracardiac levels of IL-6 in samples from the RAA (p=0.031), LA (p=0.042) and LAA (p=0.006), and MMP-9 in the LAA sample were also associated with AF (p=0.007).
The normal levels of C-reactive protein and IL-6, along with the elevated levels of IL-8 in patients with permanent AF but not in those with paroxysmal AF, suggest a link between a low-grade inflammatory reaction and long-lasting AF.