Cardiac fibrosis in patients with atrial fibrillation: Mechanisms and clinical implications

atrial fibrillation, heart failure, cardiac fibrosisAtrial fibrillation (AF) is associated with structural, electrical and contractile remodeling of the atria. Development and progression of atrial fibrosis is the hallmark of structural remodeling in AF and is considered to be substrate for AF perpetuation. In contrast, experimental and clinical data on impact of ventricular fibrotic processes in pathogenesis of AF and its complications are controversial. Ventricular fibrosis appears to contribute to abnormalities in cardiac relaxation and contractility, and development of heart failure, a common finding in AF. Given the frequent coexistence of AF and heart failure and the fact that both conditions affect patient prognosis better understanding of mutual impact of fibrosis in AF and heart failure is of particular interest. In this review article, we provide an overview on the general mechanisms of cardiac fibrosis in AF, differences between fibrotic processes in atria and ventricles, and the clinical and prognostic significance of cardiac fibrosis in AF

Cardiac fibrosis in patients with atrial fibrillation: Mechanisms and clinical implications

atrial fibrillation, heart failure, cardiac fibrosisAtrial fibrillation (AF) is associated with structural, electrical and contractile remodeling of the atria. Development and progression of atrial fibrosis is the hallmark of structural remodeling in AF and is considered to be substrate for AF perpetuation. In contrast, experimental and clinical data on impact of ventricular fibrotic processes in pathogenesis of AF and its complications are controversial. Ventricular fibrosis appears to contribute to abnormalities in cardiac relaxation and contractility, and development of heart failure, a common finding in AF. Given the frequent coexistence of AF and heart failure and the fact that both conditions affect patient prognosis better understanding of mutual impact of fibrosis in AF and heart failure is of particular interest. In this review article, we provide an overview on the general mechanisms of cardiac fibrosis in AF, differences between fibrotic processes in atria and ventricles, and the clinical and prognostic significance of cardiac fibrosis in AF

Imaging, biomarker and invasive assessment of diffuse left ventricular myocardial fibrosis in atrial fibrillation

Background Using cardiovascular magnetic resonance imaging (CMR), it is possible to detect diffuse fibrosis of the left ventricle (LV) in patients with atrial fibrillation (AF), which may be independently associated with recurrence of AF after ablation. By conducting CMR, clinical, electrophysiology and biomarker assessment we planned to investigate LV myocardial fibrosis in patients undergoing AF ablation. Methods LV fibrosis was assessed by T1 mapping in 31 patients undergoing percutaneous ablation for AF. Galectin-3, coronary sinus type I collagen C terminal telopeptide (ICTP), and type III procollagen N terminal peptide were measured with ELISA. Comparison was made between groups above and below the median for LV extracellular volume fraction (ECV), followed by regression analysis. Results On linear regression analysis LV ECV had significant associations with invasive left atrial pressure (Beta 0.49, P = 0.008) and coronary sinus ICTP (Beta 0.75, P < 0.001), which remained significant on multivariable regression. Conclusion LV fibrosis in patients with AF is associated with left atrial pressure and invasively measured levels of ICTP turnover biomarker

Interaction of heart failure and stroke: A clinical consensus statement of the ESC Council on Stroke, the Heart Failure Association (HFA) and the ESC Working Group on Thrombosis.

Heart failure (HF) is a major disease in our society that often presents with multiple comorbidities with mutual interaction and aggravation. The comorbidity of HF and stroke is a high risk condition that requires particular attention to ensure early detection of complications, efficient diagnostic workup, close monitoring, and consequent treatment of the patient. The bi-directional interaction between the heart and the brain is inherent in the pathophysiology of HF where HF may be causal for acute cerebral injury, and - in turn - acute cerebral injury may induce or aggravate HF via imbalanced neural and neurovegetative control of cardiovascular regulation. The present document represents the consensus view of the ESC Council on Stroke, the Heart Failure Association and the ESC Working Group on Thrombosis to summarize current insights on pathophysiological interactions of the heart and the brain in the comorbidity of HF and stroke. Principal aspects of diagnostic workup, pathophysiological mechanisms, complications, clinical management in acute conditions and in long-term care of patients with the comorbidity are presented and state-of-the-art clinical management and current evidence from clinical trials is discussed. Beside the physicians perspective, also the patients values and preferences are taken into account. Interdisciplinary cooperation of cardiologists, stroke specialists, other specialists and primary care physicians is pivotal to ensure optimal treatment in acute events and in continued long-term treatment of these patients. Key consensus statements are presented in a concise overview on mechanistic insights, diagnostic workup, prevention and treatment to inform clinical acute and continued care of patients with the comorbidity of HF and stroke

Sources of heterogeneity in human monocyte subsets

AbstractHuman monocytes are commonly defined and discriminated by the extent of their cell surface expression of CD14 and CD16, with associated differences in function and phenotype related to the intensity of expression of these markers. With increasing interest into the function and behaviour of monocytes, it is important to have a clear understanding of how differing strategies of analysis can affect results and how different protocols and population backgrounds can affect this highly morphogenic cell type.Using PBMCs from populations with differing ethnicities and histories of parasite exposure we have characterized monocyte phenotype based on intensity of CD14 and CD16 expression. Using the surface markers HLA-DR, CCR2 and CX3CR1, we compared monocyte phenotype between populations and further assessed changes in monocytes with freezing and thawing of PBMCs.Our results reveal that there is a progression of surface marker expression based on intensity of CD14 or CD16 expression, stressing the importance of careful gating of monocyte subtypes. Freezing and thawing of the PBMCs has no effect generally on the monocytes, although it does lead to a decrease in CD16 and CX3CR1 expression. We show that there are differences in the monocyte populations based on ethnicity and history of exposure to the common parasites Plasmodium falciparum and Schistosoma haematobium.This study highlights that blood monocytes consist of a continuous population of cells, within which the dominant phenotype may vary dependent on the background of the study population. Comparing results from monocyte studies therefore needs to be done with great care, as ethnic background of donor population, gating strategy and processing of PBMCs may all have an effect on outcome of monocyte phenotype

Heart Rate-Corrected QT Interval Helps Predict Mortality after Intentional Organophosphate Poisoning

INTRODUCTION: In this study, we investigated the outcomes for patients with intentional organophosphate poisoning. Previous reports indicate that in contrast to normal heart rate-corrected QT intervals (QTc), QTc prolongation might be indicative of a poor prognosis for patients exposed to organophosphates. METHODS: We analyzed the records of 118 patients who were referred to Chang Gung Memorial Hospital for management of organophosphate poisoning between 2000 and 2011. Patients were grouped according to their initial QTc interval, i.e., normal (<0.44 s) or prolonged (>0.44 s). Demographic, clinical, laboratory, and mortality data were obtained for analysis. RESULTS: The incidence of hypotension in patients with prolonged QTc intervals was higher than that in the patients with normal QTc intervals (P = 0.019). By the end of the study, 18 of 118 (15.2%) patients had died, including 3 of 75 (4.0%) patients with normal QTc intervals and 15 of 43 (34.9%) patients with prolonged QTc intervals. Using multivariate-Cox-regression analysis, we found that hypotension (OR = 10.930, 95% CI = 2.961-40.345, P = 0.000), respiratory failure (OR = 4.867, 95% CI = 1.062-22.301, P = 0.042), coma (OR = 3.482, 95% CI = 1.184-10.238, P = 0.023), and QTc prolongation (OR = 7.459, 95% CI = 2.053-27.099, P = 0.002) were significant risk factors for mortality. Furthermore, it was revealed that non-survivors not only had longer QTc interval (503.00±41.56 versus 432.71±51.21 ms, P = 0.002), but also suffered higher incidences of hypotension (83.3 versus 12.0%, P = 0.000), shortness of breath (64 versus 94.4%, P = 0.010), bronchorrhea (55 versus 94.4%, P = 0.002), bronchospasm (50.0 versus 94.4%, P = 0.000), respiratory failure (94.4 versus 43.0%, P = 0.000) and coma (66.7 versus 11.0%, P = 0.000) than survivors. Finally, Kaplan-Meier analysis demonstrated that cumulative mortality was higher among patients with prolonged QTc intervals than among those with normal QTc intervals (Log-rank test, Chi-square test = 20.36, P<0.001). CONCLUSIONS: QTc interval helps predict mortality after intentional organophosphate poisoning

Differential IL-1β secretion by monocyte subsets is regulated by Hsp27 through modulating mRNA stability.

Monocytes play a central role in regulating inflammation in response to infection or injury, and during auto-inflammatory diseases. Human blood contains classical, intermediate and non-classical monocyte subsets that each express characteristic patterns of cell surface CD16 and CD14; each subset also has specific functional properties, but the mechanisms underlying many of their distinctive features are undefined. Of particular interest is how monocyte subsets regulate secretion of the apical pro-inflammatory cytokine IL-1β, which is central to the initiation of immune responses but is also implicated in the pathology of various auto-immune/auto-inflammatory conditions. Here we show that primary human non-classical monocytes, exposed to LPS or LPS + BzATP (3'-O-(4-benzoyl)benzyl-ATP, a P2X7R agonist), produce approx. 80% less IL-1β than intermediate or classical monocytes. Despite their low CD14 expression, LPS-sensing, caspase-1 activation and P2X7R activity were comparable in non-classical monocytes to other subsets: their diminished ability to produce IL-1β instead arose from 50% increased IL-1β mRNA decay rates, mediated by Hsp27. These findings identify the Hsp27 pathway as a novel therapeutic target for the management of conditions featuring dysregulated IL-1β production, and represent an advancement in understanding of both physiological inflammatory responses and the pathogenesis of inflammatory diseases involving monocyte-derived IL-1β

Microparticles from apoptotic platelets promote resident macrophage differentiation

Platelets shed microparticles not only upon activation, but also upon ageing by an apoptosis-like process (apoptosis-induced platelet microparticles, PMap). While the activation-induced microparticles have widely been studied, not much is known about the (patho)physiological consequences of PMap formation. Flow cytometry and scanning electron microscopy demonstrated that PMap display activated integrins and interact to form microparticle aggregates. PMap were chemotactic for monocytic cells, bound to these cells, an furthermore stimulated cell adhesion and spreading on a fibronectin surface. After prolonged incubation, PMap promoted cell differentiation, but inhibited proliferation. Monocyte membrane receptor analysis revealed increased expression levels of CD11b (integrin αMβ2), CD14 and CD31 (platelet endothelial cell adhesion molecule-1), and the chemokine receptors CCR5 and CXCR4, but not of CCR2. This indicated that PMap polarized the cells into resident M2 monocytes. Cells treated with PMap actively consumed oxidized low-density lipoprotein (oxLDL), and released matrix metalloproteinases and hydrogen peroxide. Further confirmation for the differentiation towards resident professional phagocytes came from the finding that PMap stimulated the expression of the (ox)LDL receptors, CD36 and CD68, and the production of proinflammatory and immunomodulating cytokines by monocytes. In conclusion, interaction of PMap with monocytic cells has an immunomodulating potential. The apoptotic microparticles polarize the cells into a resident M2 subset, and induce differentiation to resident professional phagocytes

Cerebrovascular, Cognitive and Cardiac Benefits of SGLT2 Inhibitors Therapy in Patients with Atrial Fibrillation and Type 2 Diabetes Mellitus: Results from a Global Federated Health Network Analysis

Background: Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are effective anti-diabetic drugs improving cardiovascular outcomes in type 2 diabetes mellitus (T2DM) patients. This study investigated cardiovascular, cerebrovascular and cognitive outcomes of SGLT2i therapy in patients with atrial fibrillation (AF) and T2DM. Methods: Observational study using TriNetX, a global health research network of anonymised electronic medical records from real-world patients between January 2018 and December 2019. The network includes healthcare organisations globally but predominately in the United States. AF patients (ICD-10-CM code: I48) with T2DM were divided according to SGLT2i use or not, and balanced using propensity score matching (PSM). Patients were followed-up for 3-years. The primary endpoints were ischaemic stroke/transient ischemic attack (TIA), intracranial haemorrhage (ICH), and incident dementia. Secondary endpoints were incident heart failure and mortality. Results: We identified 89,356 AF patients with T2DM of which 5061 (5.7%) were taking a SGLT2i. After PSM, 5049 patients (mean age 66.7 ± 10.6 years; 28.9% female) were included in each group. At 3-years follow-up, the risk of ischaemic stroke/TIA was higher in patients not receiving SGLT2i (HR 1.12, 95% CI 1.01–1.24) and for ICH (HR 1.57, 95% CI 1.25–1.99) and incident dementia (HR 1.66, 95% CI 1.30–2.12). Incident heart failure (HR 1.50, 95% CI 1.34–1.68) and mortality (HR 1.77, 95% CI 1.58–1.99) risks were increased in AF patients not receiving SGLT2i. Conclusions: In our large ‘real world’ analysis of patients with concomitant AF and T2DM, SGLT2i reduced the risk of cerebrovascular events, incident dementia, heart failure and death

Quantification of Circulating Endothelial Progenitor Cells Using the Modified ISHAGE Protocol

Circulating endothelial progenitor cells (EPC), involved in endothelial regeneration, neovascularisation, and determination of prognosis in cardiovascular disease can be characterised with functional assays or using immunofluorescence and flow cytometry. Combinations of markers, including CD34+KDR+ or CD133+KDR+, are used. This approach, however may not consider all characteristics of EPC. The lack of a standardised protocol with regards to reagents and gating strategies may account for the widespread inter-laboratory variations in quantification of EPC. We, therefore developed a novel protocol adapted from the standardised so-called ISHAGE protocol for enumeration of haematopoietic stem cells to enable comparison of clinical and laboratory data.In 25 control subjects, 65 patients with coronary artery disease (CAD; 40 stable CAD, 25 acute coronary syndrome/acute myocardial infarction (ACS)), EPC were quantified using the following approach: Whole blood was incubated with CD45, KDR, and CD34. The ISHAGE sequential strategy was used, and finally, CD45(dim)CD34(+) cells were quantified for KDR. A minimum of 100 CD34(+) events were collected. For comparison, CD45(+)CD34(+) and CD45(-)CD34(+) were analysed simultaneously. The number of CD45(dim)CD34(+)KDR(+) cells only were significantly higher in healthy controls compared to patients with CAD or ACS (p = 0.005 each, p<0.001 for trend). An inverse correlation of CD45(dim)CD34(+)KDR(+) with disease activity (r = -0.475, p<0.001) was confirmed. Only CD45(dim)CD34(+)KDR(+) correlated inversely with the number of diseased coronaries (r = -0.344; p<0.005). In a second study, a 4-week de-novo treatment of atorvastatin in stable CAD evoked an increase only of CD45(dim)CD34(+)KDR(+) EPC (p<0.05). CD45(+)CD34(+)KDR(+) and CD45(-)CD34(+)KDR(+) were indifferent between the three groups.Our newly established protocol adopted from the standardised ISHAGE protocol achieved higher accuracy in EPC enumeration confirming previous findings with respect to the correlation of EPC with disease activity and the increase of EPC during statin therapy. The data of this study show the CD45(dim) fraction to harbour EPC