Changes of calcium cycling in HFrEF and HFpEF

Area of Science:

• Cardiology
• Molecular Biology
• Biochemistry

Background:

• Calcium (Ca2+) cycling is crucial for cardiac function.
• Dysregulation of Ca2+ handling is implicated in heart failure (HF).
• Distinct mechanisms of Ca2+ dysregulation exist in heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF).

Purpose of the Study:

• To summarize the distinct alterations in Ca2+ cycling in HFrEF and HFpEF.
• To discuss potential therapeutic targets related to Ca2+ handling in HF.

Main Methods:

• Review and synthesis of existing literature on Ca2+ cycling in HFrEF and HFpEF.
• Analysis of key molecular players involved in Ca2+ handling, including the Na+/Ca2+ exchanger and T-tubules.
• Comparison of Ca2+ concentrations in cytoplasmic and mitochondrial compartments.

Main Results:

• Both HFrEF and HFpEF exhibit diastolic Ca2+ leakage.
• HFrEF shows reduced cytoplasmic Ca2+ due to Na+/Ca2+ exchanger compensation and decreased T-tubule density, impairing systolic function.
• HFpEF demonstrates increased cytoplasmic Ca2+ and diastolic dysfunction, with altered mitochondrial Ca2+ impacting contractility differently than in HFrEF.

Conclusions:

• Calcium cycling abnormalities are central to the pathophysiology of both HFrEF and HFpEF.
• Targeting specific aspects of Ca2+ handling may offer therapeutic avenues for different HF subtypes.
• Further research into mitochondrial and cytoplasmic Ca2+ regulation is warranted for effective HF treatment.