Inflammatory activation and endothelial dysfunction markers in patients with permanent atrial fibrillation: a cross-sectional study

Circulating adipose tissue proteins involved in atrial fibrillation: An explorative scoping review

Obesity increases the risk of atrial fibrillation (AF), potentially through proteins secreted by adipose tissue (AT) that affect atrial electrical and structural remodeling. We aim to give a comprehensive overview of circulating AT proteins involved in inflammation and fibrosis, that are associated with prevalent AF (paroxysmal or persistent) and the risk on developing new-onset AF. These include adipokines, defined as proteins enriched in AT as adiponectin, but also proteins less specific to AT. We systematically performed an explorative search for studies reporting associations between proteins secreted from cells residing in the AT and AF, and additionally assessed the effect of obesity on these proteins by a secondary search. The AT proteins involved in inflammation were mostly increased in patients with prevalent and new-onset AF, and with obesity, while the AT enriched adipokines were mostly not associated with AF. This review provides insight into circulating adipose tissue proteins involved in AF substrate formation.

One-year Aerobic Interval Training Improves Endothelial Dysfunction in Patients with Atrial Fibrillation: A Randomized Trial

Objective To evaluate the effects of one-year aerobic interval training on endothelial dysfunction in patients with atrial fibrillation. Methods Seventy-four patients with atrial fibrillation (53 men, 21 women; mean age 63±6 years old) were randomized into a 1-year continuous aerobic interval training (CT), 6-month detraining after 6 months of aerobic interval training (DT), or medical treatment only (MT) group. Aerobic interval training was performed 3 times a week for 1 year or 6 months, with an exercise intensity of 85-95% of the peak heart rate. The primary outcome was a change in biomarkers of endothelial dysfunction from baseline at six months or at the one-year follow-up. Results Six-month aerobic interval training reduced von Willebrand factor (CT: 103.7±30.7 IU/dL and DT: 106±31.2 IU/dL vs. MT: 145±47.7 IU/dL, p=0.044). Improvements were maintained with continuous aerobic interval training; however, the values increased again to the baseline levels upon detraining (CT: 84.3±39.1 IU/dL vs. DT: 122.2±27.5 IU/dL and MT: 135.9±50.4 IU/dL, p=0.002). Interleukin 1 beta levels decreased after 6 months of aerobic interval training (CT: 0.59±0.1 pg/mL and DT: 0.63±0.09 pg/mL vs. MT: 0.82±0.28 pg/mL, p=0.031), and the improvement was maintained with continuous aerobic interval training and even after detraining (CT: 0.58±0.08 pg/mL and DT: 0.62±0.09 pg/mL vs. MT: 0.86±0.28 pg/mL, p=0.015). Conclusion One-year aerobic interval training improves endothelial dysfunction in patients with atrial fibrillation and is primarily associated with the reduction in circulating thrombogenic and pro-inflammatory factors. A definitive way to sustain these improvements is the long-term continuation of aerobic training.

Ischemia with Nonobstructive Coronary Artery Disease and Atrial Cardiomyopathy-Two Sides of the Same Story?

Ischemia with nonobstructive coronary artery disease (INOCA) is increasingly recognized as a significant cause of angina, myocardial remodeling, and eventually heart failure (HF). Coronary microvascular dysfunction (CMD) is a major endotype of INOCA, and it is caused by structural and functional alterations of the coronary microcirculation. At the same time, atrial cardiomyopathy (ACM) defined by structural, functional, and electrical atrial remodeling has a major clinical impact due to its manifestations: atrial fibrillation (AF), atrial thrombosis, stroke, and HF symptoms. Both these pathologies share similar risk factors and have a high comorbidity burden. CMD causing INOCA and ACM frequently coexist. Thus, questions arise whether there is a potential link between these pathologies. Does CMD promote AF or the reverse? Which are the mechanisms that ultimately lead to CMD and ACM? Are both part of a systemic disease characterized by endothelial dysfunction? Lastly, which are the therapeutic strategies that can target endothelial dysfunction and improve the prognosis of patients with CMD and ACM? This review aims to address these questions by analyzing the existing body of evidence, offering further insight into the mechanisms of CMD and ACM, and discussing potential therapeutic strategies.

Kv1.3 Channel Blockade Improves Inflammatory Profile, Reduces Cardiac Electrical Remodeling, and Prevents Arrhythmia in Type 2 Diabetic Rats

PURPOSE

Kv1.3 channel regulates the activity of lymphocytes, macrophages, or adipose tissue and its blockade reduces inflammatory cytokine secretion and improves insulin sensitivity in animals with metabolic syndrome and in genetically obese mice. Thus, Kv1.3 blockade could be a strategy for the treatment of type 2 diabetes. Elevated circulating levels of TNFα and IL-1b mediate the higher susceptibility to cardiac arrhythmia in type 2 diabetic rats. We hypothesized that Kv1.3 channel blockade with the psoralen PAP1 could have immunomodulatory properties that prevent QTc prolongation and reduce the risk of arrhythmia in type 2 diabetic rats.

METHODS

Type 2 diabetes was induced to Sprague-Dawley rats by high-fat diet and streptozotocin injection. Diabetic animals were untreated, treated with metformin, or treated with PAP1 for 4 weeks. Plasma glucose, insulin, cholesterol, triglycerides, and cytokine levels were measured using commercial kits. ECG were recorded weekly, and an arrhythmia-inducing protocol was performed at the end of the experimental period. Action potentials were recorded in isolated ventricular cardiomyocytes.

RESULTS

In diabetic animals, PAP1 normalized glycaemia, insulin resistance, adiposity, and lipid profile. In addition, PAP1 prevented the diabetes-induced repolarization defects through reducing the secretion of the inflammatory cytokines IL-10, IL-12p70, GM-CSF, IFNγ, and TNFα. Moreover, compared to diabetic untreated and metformin-treated animals, those treated with PAP1 had the lowest risk of developing the life-threatening arrhythmia Torsade de Pointes under cardiac challenge.

CONCLUSION

Kv1.3 inhibition improves diabetes and diabetes-associated low-grade inflammation and cardiac electrical remodeling, resulting in more protection against cardiac arrhythmia compared to metformin.

Effects of dulaglutide on endothelial progenitor cells and arterial elasticity in patients with type 2 diabetes mellitus

Background

Randomised controlled trial showed that dulaglutide can reduce the risk of atherosclerotic cardiovascular disease (ASCVD) in patients with type 2 diabetes mellitus (T2DM), but the underlying mechanisms remain unclear. This study aimed to investigate the effect of dulaglutide on the number and function of endothelial progenitor cells (EPCs) in the peripheral blood of patients with T2DM and its role in improving arterial elasticity, so as to determine potential mechanisms of preventive effect of dulaglutide on ASCVD.

Methods

Sixty patients with T2DM were treated with 1000 mg/day of metformin and randomly divided into two groups for 12 weeks: metformin monotherapy group (MET group, n = 30), and metformin combined with dulaglutide group (MET-DUL group, n = 30). Before and after treatment, the number of CD34⁺CD133⁺KDR⁺ EPCs and the brachial–ankle pulse wave velocity (baPWV) of the participants were measured, and EPC proliferation, adhesion, migration, and tubule formation were assessed in vitro.

Results

There were no significant differences in the number and function of EPCs and baPWV changes in MET group (P > 0.05). In MET-DUL group, nitric oxide (NO) levels and the number of EPCs increased after treatment (P < 0.05), while the levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), advanced glycation end products (AGEs), and baPWV decreased (P < 0.05). EPC proliferation, adhesion, migration, and tubule formation abilities were significantly enhanced (P < 0.05). Correlation analysis showed that in MET-DUL group, the changes in CRP, IL-6, TNF-α, and AGEs were negatively correlated with the number of EPCs and their proliferation and migration abilities (P < 0.05). Body weight, NO, CRP, and IL-6 levels were independent factors affecting the number of EPCs (P < 0.05). The changes in number of EPCs, proliferation and migration abilities of EPCs, and NO and IL-6 levels were independent influencing factors of baPWV changes (P < 0.05).

Conclusion

Dulaglutide can increase the number and function of EPCs in peripheral blood and improve arterial elasticity in patients with T2DM; it is accompanied by weight loss, inflammation reduction, and high NO levels. Dulaglutide regulation of EPCs may be a mechanism of cardiovascular protection.

Effect of Endothelial Adhesion Molecules on Atrial Fibrillation: A Systematic Review and Meta-analysis

Background: Endothelial adhesion molecules (EAMs), and more specifically vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), belong to a family of immunoglobulin-like molecules and are found to have increased expression in inflamed microvessels. Due to the growing evidence regarding EAM effects on cardiovascular diseases, we aimed to investigate the link between EAMs and atrial fibrillation (AF) to discover the efficacy of EAMs assessment as predictive markers in high-risk patients. Methods: We searched for articles published from January 1990 to April 2022. Two independent researchers selected studies that examined the relationship between VCAM-1 and ICAM-1 levels and AF. Study design, patient characteristics, VCAM-1 and ICAM-1 levels, and measurement methods were extracted from the selected articles. Results: Of 181 records, 22 studies were finally included in the systematic review. Meta-analyses showed a significant difference in serum levels of EAMs in patients with AF compared with patients with sinus rhythms (VCAM-1: mean difference [MD] 86.782, 95% CI 22.805-150.758, p=0.008; ICAM-1: MD 28.439 ng/mL, 95% CI 12.540-44.338, p<0.001). In subgroup analysis of persistent AF, the differences were still significant (VCAM-1: MD 98.046, 95% CI 26.582-169.510, p=0.007; ICAM-1: MD 25.091, 95% CI 12.952-37.230, p<0.001). We also found the mean ranges of VCAM-1 (95% CI 661.394-927.984 ng/mL) and ICAM-1 (95% CI 190.101-318.169 ng/mL) in patients with AF. Conclusion: This study suggests a positive association between serum levels of VCAM-1 and ICAM-1 with AF, but there is a need for further large-scale studies.

Influence of endothelial function and arterial stiffness on the behavior of cervicocephalic arterial dissections: An observational study

Background

The mechanical and physiological properties of the arterial wall might affect the behavior of spontaneous cervicocephalic arterial dissections (CCAD). We aimed to determine the effects of endothelial function and arterial stiffness on the clinical characteristics and outcomes of CCAD using brachial flow-mediated dilation (FMD) and brachial-ankle pulse wave velocity (PWV).

Methods

From a single-center database, we identified patients admitted from April 2011 to December 2021 with a diagnosis of CCAD who underwent both FMD and PWV. FMD was classified as normal and decreased according to institutional thresholds. PWV was categorized into tertiles. Comparative and multivariable analyses were performed to determine the effects of FMD and PWV values on major clinical outcomes.

Results

A total of 146 patients (age: 47 ± 11 years; men: 77.4%) were included. The main presentation was ischemic stroke in 76.7% of the patients, while 23.3% presented with headache or other symptoms. Healing of the dissection was observed in 55.8%. In multivariable analysis, Normal FMD levels (vs. decreased; adjusted OR: 4.52, 95% CI [1.95 −10.52]) were associated with spontaneous healing of the dissection. Highest PWV tertile (vs. lowest; adjusted OR: 17.05, 95% CI [3.07–94.82]) was associated with ischemic presentation. There was a higher ischemic stroke recurrence in the 3rd PWV tertile, and more frequent aneurysmal enlargement in the lowest PWV tertile, but their frequency was low, precluding multivariable analysis.

Conclusion

In spontaneous CCAD, preserved endothelial function was associated with spontaneous arterial healing. Arterial stiffness is associated with ischemic presentation.

MiRNA21 and IL-18 levels in left atrial blood in patients with atrial fibrillation undergoing cryoablation and their predictive value for recurrence of atrial fibrillation

PURPOSE

The recurrence of atrial fibrillation (AF) after cryoablation still needs to be prioritized, including discriminating predictive indicators.

METHODS

Eighty-seven patients aged 43-83 years who underwent cryo-balloon ablation were divided into paroxysmal atrial fibrillation (PAF) and non-paroxysmal atrial fibrillation (non-PAF) groups. Baseline data, intraoperative index, and miRNA21, IL-18, NLRP3, and visfatin levels in peripheral venous blood and left atrial blood were assessed. Follow-up was performed for 6 months to observe the recurrence of AF. A Cox risk ratio model was used to analyze indicators for predicting AF recurrence.

RESULTS

The non-PAF and PAF group recurrence rates of AF were statistically different (p < 0.05) at 9/22 (40.9%) and 11/65 (16.9%), respectively. Biomarker levels in the left atrial blood were higher in the non-PAF group than in the PAF group (p < 0.05). The effects of non-PAF and levels of miRNA21 and IL-18 in left atrial serum on the recurrence of AF after cryoablation statistically differed (p < 0.05).

CONCLUSION

The levels of miRNA21 and IL-18 were higher in left atrial blood than in peripheral blood, which may be related to the severity of AF and recurrence of AF after cryoablation.

Non-Coding RNA Networks as Potential Novel Biomarker and Therapeutic Target for Sepsis and Sepsis-Related Multi-Organ Failure

According to “Sepsis-3” consensus, sepsis is a life-threatening clinical syndrome caused by a dysregulated inflammatory host response to infection. A rapid identification of sepsis is mandatory, as the extent of the organ damage triggered by both the pathogen itself and the host’s immune response could abruptly evolve to multiple organ failure and ultimately lead to the death of the patient. The most commonly used therapeutic strategy is to provide hemodynamic and global support to the patient and to rapidly initiate broad-spectrum empiric antibiotic therapy. To date, there is no gold standard diagnostic test that can ascertain the diagnosis of sepsis. Therefore, once sepsis is suspected, the presence of organ dysfunction can be assessed using the Sepsis-related Organ Failure Assessment (SOFA) score, although the diagnosis continues to depend primarily on clinical judgment. Clinicians can now rely on several serum biomarkers for the diagnosis of sepsis (e.g., procalcitonin), and promising new biomarkers have been evaluated, e.g., presepsin and adrenomedullin, although their clinical relevance in the hospital setting is still under discussion. Non-codingRNA, including long non-codingRNAs (lncRNAs), circularRNAs (circRNAs) and microRNAs (miRNAs), take part in a complex chain of events playing a pivotal role in several important regulatory processes in humans. In this narrative review we summarize and then analyze the function of circRNAs-miRNA-mRNA networks as putative novel biomarkers and therapeutic targets for sepsis, focusing only on data collected in clinical settings in humans.

Pathogenetic Mechanisms of Hypertension-Brain-Induced Complications: Focus on Molecular Mediators

There is growing evidence that hypertension is the most important vascular risk factor for the development and progression of cardiovascular and cerebrovascular diseases. The brain is an early target of hypertension-induced organ damage and may manifest as stroke, subclinical cerebrovascular abnormalities and cognitive decline. The pathophysiological mechanisms of these harmful effects remain to be completely clarified. Hypertension is well known to alter the structure and function of cerebral blood vessels not only through its haemodynamics effects but also for its relationships with endothelial dysfunction, oxidative stress and inflammation. In the last several years, new possible mechanisms have been suggested to recognize the molecular basis of these pathological events. Accordingly, this review summarizes the factors involved in hypertension-induced brain complications, such as haemodynamic factors, endothelial dysfunction and oxidative stress, inflammation and intervention of innate immune system, with particular regard to the role of Toll-like receptors that have to be considered dominant components of the innate immune system. The complete definition of their prognostic role in the development and progression of hypertensive brain damage will be of great help in the identification of new markers of vascular damage and the implementation of innovative targeted therapeutic strategies.

Molecular Insights in Atrial Fibrillation Pathogenesis and Therapeutics: A Narrative Review

The prevalence of atrial fibrillation (AF) is bound to increase globally in the following years, affecting the quality of life of millions of people, increasing mortality and morbidity, and beleaguering health care systems. Increasingly effective therapeutic options against AF are the constantly evolving electroanatomic substrate mapping systems of the left atrium (LA) and ablation catheter technologies. Yet, a prerequisite for better long-term success rates is the understanding of AF pathogenesis and maintenance. LA electrical and anatomical remodeling remains in the epicenter of current research for novel diagnostic and treatment modalities. On a molecular level, electrical remodeling lies on impaired calcium handling, enhanced inwardly rectifying potassium currents, and gap junction perturbations. In addition, a wide array of profibrotic stimuli activates fibroblast to an increased extracellular matrix turnover via various intermediaries. Concomitant dysregulation of the autonomic nervous system and the humoral function of increased epicardial adipose tissue (EAT) are established mediators in the pathophysiology of AF. Local atrial lymphomononuclear cells infiltrate and increased inflammasome activity accelerate and perpetuate arrhythmia substrate. Finally, impaired intracellular protein metabolism, excessive oxidative stress, and mitochondrial dysfunction deplete atrial cardiomyocyte ATP and promote arrhythmogenesis. These overlapping cellular and molecular alterations hinder us from distinguishing the cause from the effect in AF pathogenesis. Yet, a plethora of therapeutic modalities target these molecular perturbations and hold promise in combating the AF burden. Namely, atrial selective ion channel inhibitors, AF gene therapy, anti-fibrotic agents, AF drug repurposing, immunomodulators, and indirect cardiac neuromodulation are discussed here.

Prevalence and predictors of subclinical atrial fibrillation in hospitalized older adults

Subclinical atrial fibrillation (SCAF) is associated with an increased risk of clinical AF, major cardiovascular events and death. Short-term evidence on SCAF in older populations is scarce, especially in the hospital setting. We performed a cross-sectional study on 60 multimorbid older consecutive patients (aged 80+) admitted to an Internal Medicine and Geriatrics Unit for acute medical diseases with no history of AF, in order to investigate prevalence and predictors of SCAF. Portable ECG monitoring was placed on admission and ECG recording lasted for 5 days. Mean age: 85.7±4.9 years. Female prevalence: 58.3%. High burden of comorbidities: 87.9%. All enrolled patients had CHA₂DS₂-VASc score ≥3. SCAF was detected in 16 patients (26.7%) and 11 patients (18.4%) had at least a SCAF episode lasting 6 minutes or longer. No clinical, laboratory and echocardiographic parameters predicted SCAF. Patients with ≥2004 supraventricular ectopic beats/24h (SVEBs/24h) had a 6-fold higher prevalence of SCAF than patients with <411 SVEBs/24h (p=0.038). Time to first SCAF episode was within 3 days of ECG recording in all enrolled patients. SCAF is highly prevalent in older adults hospitalized for acute diseases. This finding may affect clinical management and prognosis. Our study could foster larger multicenter studies in similar settings.

Molecular and Electrophysiological Role of Diabetes-Associated Circulating Inflammatory Factors in Cardiac Arrhythmia Remodeling in a Metabolic-Induced Model of Type 2 Diabetic Rat

Background: Diabetic patients have prolonged cardiac repolarization and higher risk of arrhythmia. Besides, diabetes activates the innate immune system, resulting in higher levels of plasmatic cytokines, which are described to prolong ventricular repolarization. Methods: We characterize a metabolic model of type 2 diabetes (T2D) with prolonged cardiac repolarization. Sprague-Dawley rats were fed on a high-fat diet (45% Kcal from fat) for 6 weeks, and a low dose of streptozotozin intraperitoneally injected at week 2. Body weight and fasting blood glucose were measured and electrocardiograms of conscious animals were recorded weekly. Plasmatic lipid profile, insulin, cytokines, and arrhythmia susceptibility were determined at the end of the experimental period. Outward K⁺ currents and action potentials were recorded in isolated ventricular myocytes by patch-clamp. Results: T2D animals showed insulin resistance, hyperglycemia, and elevated levels of plasma cholesterol, triglycerides, TNFα, and IL-1b. They also developed bradycardia and prolonged QTc-interval duration that resulted in increased susceptibility to severe ventricular tachycardia under cardiac challenge. Action potential duration (APD) was prolonged in control cardiomyocytes incubated 24 h with plasma isolated from diabetic rats. However, adding TNFα and IL-1b receptor blockers to the serum of diabetic animals prevented the increased APD. Conclusions: The elevation of the circulating levels of TNFα and IL-1b are responsible for impaired ventricular repolarization and higher susceptibility to cardiac arrhythmia in our metabolic model of T2D.

Role of Regular Physical Activity in Neuroprotection against Acute Ischemia

One of the major obstacles that prevents an effective therapeutic intervention against ischemic stroke is the lack of neuroprotective agents able to reduce neuronal damage; this results in frequent evolution towards a long-term disability with limited alternatives available to aid in recovery. Nevertheless, various treatment options have shown clinical efficacy. Neurotrophins such as brain-derived neurotrophic factor (BDNF), widely produced throughout the brain, but also in distant tissues such as the muscle, have demonstrated regenerative properties with the potential to restore damaged neural tissue. Neurotrophins play a significant role in both protection and recovery of function following neurological diseases such as ischemic stroke or traumatic brain injury. Unfortunately, the efficacy of exogenous administration of these neurotrophins is limited by rapid degradation with subsequent poor half-life and a lack of blood-brain-barrier permeability. Regular exercise seems to be a therapeutic approach able to induce the activation of several pathways related to the neurotrophins release. Exercise, furthermore, reduces the infarct volume in the ischemic brain and ameliorates motor function in animal models increasing astrocyte proliferation, inducing angiogenesis and reducing neuronal apoptosis and oxidative stress. One of the most critical issues is to identify the relationship between neurotrophins and myokines, newly discovered skeletal muscle-derived factors released during and after exercise able to exert several biological functions. Various myokines (e.g., Insulin-Like Growth Factor 1, Irisin) have recently shown their ability to protects against neuronal injury in cerebral ischemia models, suggesting that these substances may influence the degree of neuronal damage in part via inhibiting inflammatory signaling pathways. The aim of this narrative review is to examine the main experimental data available to date on the neuroprotective and anti-ischemic role of regular exercise, analyzing also the possible role played by neurotrophins and myokines.

Neuroinflammatory Mechanisms in Ischemic Stroke: Focus on Cardioembolic Stroke, Background, and Therapeutic Approaches

One of the most important causes of neurological morbidity and mortality in the world is ischemic stroke. It can be a result of multiple events such as embolism with a cardiac origin, occlusion of small vessels in the brain, and atherosclerosis affecting the cerebral circulation. Increasing evidence shows the intricate function played by the immune system in the pathophysiological variations that take place after cerebral ischemic injury. Following the ischemic cerebral harm, we can observe consequent neuroinflammation that causes additional damage provoking the death of the cells; on the other hand, it also plays a beneficial role in stimulating remedial action. Immune mediators are the origin of signals with a proinflammatory position that can boost the cells in the brain and promote the penetration of numerous inflammatory cytotypes (various subtypes of T cells, monocytes/macrophages, neutrophils, and different inflammatory cells) within the area affected by ischemia; this process is responsible for further ischemic damage of the brain. This inflammatory process seems to involve both the cerebral tissue and the whole organism in cardioembolic stroke, the stroke subtype that is associated with more severe brain damage and a consequent worse outcome (more disability, higher mortality). In this review, the authors want to present an overview of the present learning of the mechanisms of inflammation that takes place in the cerebral tissue and the role of the immune system involved in ischemic stroke, focusing on cardioembolic stroke and its potential treatment strategies.