Reduced PI3K(p110α) induces atrial myopathy, and PI3K-related lipids are dysregulated in athletes with atrial fibrillation.

Background: Elucidating mechanisms underlying atrial myopathy, which predisposes individuals to atrial fibrillation (AF), will be critical for preventing/treating AF. In a serendipitous discovery, we identified atrial enlargement, fibrosis, and thrombi in mice with reduced phosphoinositide 3-kinase (PI3K) in cardiomyocytes. PI3K(p110α) is elevated in the heart with exercise and is critical for exercise-induced ventricular enlargement and protection, but the role in the atria was unknown.

Molecular Imaging of Diffuse Cardiac Fibrosis with a Radiotracer That Targets Proteolyzed Collagen IV.

Purpose To develop an approach for in vivo detection of interstitial cardiac fibrosis using PET with a peptide tracer targeting proteolyzed collagen IV (T-peptide). Materials and Methods T-peptide was conjugated to the copper chelator MeCOSar (chemical name, 5-(8-methyl-3,6,10,13,16,19-hexaaza-bicyclo[6.6.

PI3K signalling at the intersection of cardio-oncology networks: cardiac safety in the era of AI.

Class I phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases. They are super elevated in many human cancer types and exert their main cellular functions by activating Akt to trigger an array of distinct responses, affecting metabolism and cell polarity. The signal equally plays important roles in cardiovascular pathophysiology.

PI3K(p110α) as a determinant and gene therapy for atrial enlargement in atrial fibrillation.

Atrial fibrillation (AF) is an irregular heart rhythm, characterised by chaotic atrial activation, which is promoted by remodelling. Once initiated, AF can also propagate the progression of itself in the so-called ''AF begets AF''. Several lines of investigation have shown that signalling molecules, including reactive oxygen species, angiotensin II, and phosphoinositide 3-kinases (PI3Ks), in presence or absence of cardiovascular disease risk factors, stabilise and promote AF maintenance.

Assessment of the epi-pericardial fibrotic substrate by collagen-targeted probes.

The identification of the fibrotic arrhythmogenic substrate as a means of improving the diagnosis and prediction of atrial fibrillation has been a focus of research for many years. The relationship between the degree of atrial fibrosis as a major component of atrial cardiomyopathy and the recurrence of arrhythmia after AF ablation can correlate. While the focus in identification and characterisation of this substrate has been centred on the atrial wall and the evaluation of atrial scar and extracellular matrix (ECM) expansion by late gadolinium-enhancement (LGE) on cardiac magnetic resonance imaging (CMRI), LGE cannot visualise diffuse fibrosis and diffuse extravasation of gadolinium.

Collagen-Targeted Peptides for Molecular Imaging of Diffuse Cardiac Fibrosis.

Background Cardiac fibrosis is the excessive deposition of extracellular matrix in the heart, triggered by a cardiac insult, aging, genetics, or environmental factors. Molecular imaging of the cardiac extracellular matrix with targeted probes could improve diagnosis and treatment of heart disease. However, although this technology has been used to demonstrate focal scarring arising from myocardial infarction, its capacity to demonstrate extracellular matrix expansion and diffuse cardiac fibrosis has not been assessed.

Pathophysiology and therapeutic relevance of PI3K(p110α) protein in atrial fibrillation: A non-interventional molecular therapy strategy.

Genetically modified animal studies have revealed specific expression patterns and unequivocal roles of class I PI3K isoenzymes. PI3K(p110α), a catalytic subunit of class I PI3Ks is ubiquitously expressed and is well characterised in the cardiovascular system. Given that genetic inhibition of PI3K(p110α) causes lethal phenotype embryonically, the catalytic subunit is critically important in housekeeping and biological processes.

Molecular imaging of atrial myopathy: Towards early AF detection and non-invasive disease management.

Atrial fibrillation (AF) is a common arrhythmia that can lead to stroke. The diseased muscle tissue of the atria develops atrial fibrosis, inflammation, thrombosis and subsequent strokes, resulting in significant morbidity and mortality. Current diagnostic and evaluation paradigms for clinical AF focus on identifying functional and morphological abnormalities of the left atria by echocardiography.

Electrical and structural remodeling contribute to atrial fibrillation in type 2 diabetic db/db mice.

Background: Atrial fibrillation (AF) is highly prevalent in diabetes mellitus (DM), yet the basis for this finding is poorly understood. Type 2 DM may be associated with unique patterns of atrial electrical and structural remodeling; however, this has not been investigated in detail.

Objective: The purpose of this study was to investigate AF susceptibility and atrial electrical and structural remodeling in type 2 diabetic db/db mice.

Aberrant cardiac metabolism leads to cardiac arrhythmia.

Diabetes, obesity and increased body mass index are associated with changes in metabolism that lead to an inadequate reservoir or use of ATP in the heart and susceptibility to arrhythmia. Lack of availability of ATP and abnormal levels of metabolic end products can cause gene reprogramming and electrical remodelling that make myfibers susceptible to arrhythmia. Understanding the metabolic aberrations that lead to arrhythmia require better understanding of cardiac metabolism.

Loss of insulin signaling may contribute to atrial fibrillation and atrial electrical remodeling in type 1 diabetes.

Atrial fibrillation (AF) is prevalent in diabetes mellitus (DM); however, the basis for this is unknown. This study investigated AF susceptibility and atrial electrophysiology in type 1 diabetic Akita mice using in vivo intracardiac electrophysiology, high-resolution optical mapping in atrial preparations, and patch clamping in isolated atrial myocytes. qPCR and western blotting were used to assess ion channel expression.

TRP Channels Mediated Pathological Ca-Handling and Spontaneous Ectopy.

Ion channel biology offers great opportunity in identifying and learning about cardiac pathophysiology mechanisms. The discovery of transient receptor potential (TRP) channels is an add-on to the opportunity. Interacting with numerous signaling pathways, being activated multimodally, and having prescribed signatures underlining acute hemodynamic control and cardiac remodeling, TRP channels regulate cardiac pathophysiology.

Necessity to evaluate PI3K/Akt signalling pathway in proarrhythmia.

The incidence of QT prolongation and torsades de pointes is on the rise due to the use of cardiovascular and non-cardiovascular drugs. Robust efforts have been made and are still ongoing to understand the underlying mechanisms that can enhance or prevent the development of drug-induced proarrhythmia. A caveat in the use of antiarrhythmic drugs is the ability to obtain safe action potential prolongation therapeutic effects, through IKr blockade.

A New Perspective of Lysosomal Cation Channel-Dependent Homeostasis in Alzheimer's Disease.

Studies have reported typically biophysical lysosomal cation channels including TPCs. Their plausible biological roles are being elucidated by pharmacological, genetic and conventional patch clamp procedures. The best characterized so far among these channels is the ML1 isoform of TRP.

Infection, inflammation and prostate carcinogenesis.

Several reports have shown that the incidence of prostate cancer is on the increase and that more men would be diagnosed of prostate cancer in the next decades. Many approaches are being applied towards reducing the cases of prostate cancer, especially in the very rich countries. However, these have not been effective due to the poor current understanding of the pathophysiology of prostate carcinogenesis.