Changes in Repolarizing Currents in Mouse Cardiomyocytes Following Chronic Atorvastatin Exposure

Area of Science:

• Cardiology
• Pharmacology
• Electrophysiology

Background:

• Statins are widely prescribed globally, yet their chronic effects on cardiac electrical activity remain under-investigated.
• Understanding how statins influence heart cell electrophysiology is crucial for patient safety and therapeutic optimization.

Purpose of the Study:

• To investigate the impact of chronic atorvastatin exposure on key repolarizing potassium currents in ventricular cardiomyocytes.
• To determine if atorvastatin alters the ultrarapid delayed rectifier potassium current (I_Kur), transient outward potassium current (I_to), or inward rectifier potassium current (I_K1).

Main Methods:

• Ventricular cardiomyocytes were isolated from mice subjected to chronic atorvastatin administration (10 mg/kg/day for 1 month).
• Whole-cell patch-clamp technique was employed to measure ion channel currents.

Main Results:

• A significant increase of approximately 40% in the ultrarapid delayed rectifier potassium current (I_Kur) was observed in atorvastatin-treated mice compared to controls.
• No significant changes were detected in the transient outward potassium current (I_to) or the inward rectifier potassium current (I_K1).
• Action potential configuration remained unchanged, suggesting compensatory mechanisms or effects on other ion currents.

Conclusions:

• Chronic atorvastatin exposure selectively enhances the I_Kur in mouse ventricular cardiomyocytes.
• The observed changes in I_Kur, despite unaltered action potential morphology, indicate potential complex electrophysiological modulations by statins.
• Further research is needed to explore the effects of atorvastatin on depolarizing currents and the overall clinical implications.