Na(+) current expression in human atrial myofibroblasts: identity and functional roles

Area of Science:

• Cardiology
• Cell Biology
• Biophysics

Background:

• Fibroblasts and myofibroblasts have crucial roles in heart health and disease.
• Human atrial myofibroblasts may express a sodium current (INa), potentially influencing cardiac electrical activity.

Purpose of the Study:

• Characterize the electrophysiological and molecular properties of INa in human atrial myofibroblasts.
• Investigate the biophysical and pharmacological aspects of this INa.
• Model the functional consequences of fibroblast INa in cardiac rhythm disturbances.

Main Methods:

• Electrophysiological characterization of INa in cultured human atrial myofibroblasts.
• Molecular identification of Na(+) channel subunits (α and β).
• Mathematical modeling of myocyte-fibroblast coupling.

Main Results:

• Approximately 40-50% of human atrial myofibroblasts express INa.
• INa appears to be generated by a combination of Nav1.9, Nav1.2, and Nav1.5 channels.
• Mathematical modeling integrated experimental data to illustrate functional consequences.

Conclusions:

• Human atrial myofibroblasts possess a functional INa, challenging the view of fibroblasts as passive cells.
• The identified Na(+) channel subtypes suggest fibroblasts can actively participate in cardiac electrical signaling.
• Findings provide a basis for reconsidering pharmacological treatments for supraventricular rhythm disorders like atrial fibrillation.