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Role of the mitochondrial permeability transition in myocardial disease
James N Weiss1, Paavo Korge, Henry M Honda
1Cardiovascular Research Laboratory, Department of Medicine (Cardiology), David Geffen School of Medicine at UCLA, Los Angeles, Calif 90095-1760, USA. jweiss@mednet.ucla.edu
Abstract:
Mitochondria play a key role in determining cell fate during exposure to stress. Their role during ischemia/reperfusion is particularly critical because of the conditions that promote both apoptosis by the mitochondrial pathway and necrosis by irreversible damage to mitochondria in association with mitochondrial permeability transition (MPT). MPT is caused by the opening of permeability transition pores in the inner mitochondrial membrane, leading to matrix swelling, outer membrane rupture, release of apoptotic signaling molecules such as cytochrome c from the intermembrane space, and irreversible injury to the mitochondria. During ischemia (the MPT priming phase), factors such as intracellular Ca2+ accumulation, long-chain fatty acid accumulation, and reactive oxygen species progressively increase mitochondrial susceptibility to MPT, increasing the likelihood that MPT will occur on reperfusion (the MPT trigger phase). Because functional cardiac recovery ultimately depends on mitochondrial recovery, cardioprotection by ischemic and pharmacological preconditioning must ultimately involve the prevention of MPT. Investigations into this area are beginning to unravel some of the mechanistic links between cardioprotective signaling and mitochondria.
Insights
Mitochondria are crucial for cell survival during stress, especially during ischemia/reperfusion injury. Preventing mitochondrial permeability transition (MPT) is key to protecting the heart and promoting recovery.
Area of Science:
- Cardiovascular Biology
- Cellular Stress Response
- Mitochondrial Medicine
Background:
- Mitochondria critically influence cell fate under stress, particularly during ischemia/reperfusion (I/R).
- I/R conditions can trigger both apoptosis and necrosis through mitochondrial damage and the mitochondrial permeability transition (MPT).
Purpose of the Study:
- To elucidate the role of mitochondria and MPT in I/R injury.
- To explore how preventing MPT contributes to cardioprotection.
Main Methods:
- Review of mechanisms underlying MPT during ischemia and reperfusion.
- Analysis of factors contributing to MPT, including calcium, fatty acids, and reactive oxygen species.
- Examination of the link between cardioprotective strategies and MPT prevention.
Main Results:
- MPT, caused by the opening of mitochondrial permeability transition pores, leads to irreversible mitochondrial damage and cell death.
- Ischemia primes mitochondria for MPT through accumulated intracellular factors, while reperfusion triggers the event.
- Cardioprotection, via preconditioning, must target MPT prevention for effective cardiac recovery.
Conclusions:
- Mitochondrial recovery is essential for functional cardiac recovery post-I/R.
- Preventing MPT is a critical therapeutic target for cardioprotection.
- Ongoing research aims to clarify the mechanistic links between cardioprotective signaling and mitochondrial function.