L-type Ca2+ channels provide a major pathway for iron entry into cardiomyocytes in iron-overload cardiomyopathy

Area of Science:

• Cardiology
• Cardiovascular Research
• Iron Metabolism

Background:

• Iron overload cardiomyopathy is a critical determinant of survival in patients with iron overload disorders.
• Myocardial iron accumulation is a key factor contributing to cardiac dysfunction and mortality.
• The precise mechanisms of iron transport into cardiomyocytes remain incompletely understood.

Purpose of the Study:

• To investigate the role of L-type voltage-dependent Ca2+ channels (LVDCCs) in mediating cardiac iron accumulation.
• To evaluate the therapeutic potential of LVDCC blockers (calcium channel blockers, CCBs) in mitigating iron overload cardiomyopathy.

Main Methods:

• Iron overload was induced in mice, and cardiac function, mortality, fibrosis, and oxidative stress were assessed.
• Mice were treated with CCBs (amlodipine and verapamil) to assess their protective effects.
• Transgenic mice with cardiac-specific overexpression of the LVDCC alpha1-subunit were used to confirm the role of LVDCCs in iron uptake.

Main Results:

• Iron overload in mice led to increased mortality, cardiac dysfunction, fibrosis, and oxidative stress.
• CCB treatment attenuated myocardial iron accumulation, reduced oxidative stress, improved cardiac function, and enhanced survival.
• Cardiac-specific overexpression of the LVDCC alpha1-subunit exacerbated iron accumulation and cardiac dysfunction, which was reversed by LVDCC blockade.

Conclusions:

• Cardiac L-type voltage-dependent Ca2+ channels (LVDCCs) are identified as key transporters of ferrous iron (Fe2+) into cardiomyocytes during iron overload.
• LVDCCs represent a potential novel therapeutic target for reducing the cardiovascular burden associated with iron overload disorders.