Mitochondrial dysfunction in heart failure.

Area of Science:

• Cardiovascular Physiology
• Mitochondrial Biology
• Skeletal Muscle Metabolism

Background:

• Heart failure (HF) is a complex syndrome characterized by impaired cardiac and skeletal muscle function.
• A chronic energy deficit is a significant factor contributing to the development of myopathy in HF patients.
• Altered bioenergetics in HF include impaired oxygen availability, substrate oxidation, and ATP production/transfer.

Purpose of the Study:

• To review alterations in mitochondrial biogenesis and function in HF.
• To examine the contribution of altered bioenergetics to energy deficit and mechanical dysfunction in HF.
• To evaluate factors contributing to systemic energy deficit in HF.

Main Methods:

• Review of existing literature on mitochondrial function in heart failure.
• Analysis of bioenergetic pathways, including substrate oxidation and ATP synthesis.
• Evaluation of mitochondrial populations (subsarcolemmal and interfibrillar) in cardiac and skeletal muscle.

Main Results:

• HF is associated with decreased mitochondrial biogenesis and function in both cardiac and skeletal muscle.
• This suggests a systemic mitochondrial cytopathy in HF.
• Mitochondrial defects are located in the electron transport and phosphorylation apparatus, varying by HF etiology and progression.

Conclusions:

• HF involves a systemic mitochondrial defect affecting both heart and skeletal muscles.
• Altered mitochondrial function contributes significantly to the energy deficit and mechanical dysfunction in HF.
• Adrenergic stimulation, mediated by cyclic AMP, may play a role in mitochondrial dysfunction in HF.