Aggravation of cardiac myofibroblast arrhythmogeneicity by mechanical stress

Aggravation of cardiac myofibroblast arrhythmogeneicity by mechanical stress.

AIMS Myofibroblasts (MFBs) as appearing in the myocardium during fibrotic remodelling induce slow conduction following heterocellular gap junctional coupling with cardiomyocytes (CMCs) in bioengineered tissue preparations kept under isometric conditions. In this study, we investigated the hypothesis that strain as developed during diastolic filling of the heart chambers may modulate MFB-depende...

Cellular Biology Abolishing Myofibroblast Arrhythmogeneicity by Pharmacological Ablation of -Smooth Muscle Actin Containing Stress Fibers

Abolishing myofibroblast arrhythmogeneicity by pharmacological ablation of α-smooth muscle actin containing stress fibers.

RATIONALE Myofibroblasts typically appear in the myocardium after insults to the heart like mechanical overload and infarction. Apart from contributing to fibrotic remodeling, myofibroblasts induce arrhythmogenic slow conduction and ectopic activity in cardiomyocytes after establishment of heterocellular electrotonic coupling in vitro. So far, it is not known whether α-smooth muscle actin (α-SM...

Mechanical force regulation of myofibroblast differentiation in cardiac fibroblasts.

The myocardium responds to chronic pressure or volume overload by activation and proliferation of cardiac fibroblasts and their differentiation into myofibroblasts. Because alpha-smooth muscle actin (SMA) expression is the classical marker for myofibroblast differentiation, we examined force-induced SMA expression and regulation by specific MAPK pathways. Rat cardiac fibroblasts were separated ...

Regulation of myofibroblast differentiation by cardiac glycosides.

Myofibroblast differentiation is a key process in pathogenesis of fibrotic diseases. Cardiac glycosides (ouabain, digoxin) inhibit Na(+)-K(+)-ATPase, resulting in increased intracellular [Na(+)]-to-[K(+)] ratio in cells. Microarray analysis suggested that increased intracellular [Na(+)]/[K(+)] ratio may promote the expression of cyclooxygenase-2 (COX-2), a critical enzyme in the synthesis of pr...