Diazoxide prevents reactive oxygen species and mitochondrial damage, leading to anti-hypertrophic effects

Area of Science:

• Cardiology
• Mitochondrial Physiology
• Pharmacology

Background:

• Pathological cardiac hypertrophy, marked by heart wall thickening or chamber enlargement, leads to mitochondrial dysfunction and oxidative stress.
• Mitochondrial ATP-sensitive K+ channels (mitoKATP) play a role in cellular redox balance and protection against cardiac insults.

Purpose of the Study:

• To investigate whether opening mitoKATP with diazoxide can prevent isoproterenol-induced cardiac hypertrophy in vivo.
• To determine if mitoKATP opening mitigates reactive oxygen species (ROS) production and mitochondrial calcium-induced swelling.

Main Methods:

• Cardiac hypertrophy was induced in Swiss mice using isoproterenol (30 mg/kg/day) for 8 days.
• Diazoxide was administered to open mitoKATP, and 5-hydroxydecanoate was used as a mitoKATP blocker.
• Measurements included heart weight/tibia length ratios, myocyte cross-sectional areas, H2O2 production, glutathione peroxidase activity, and mitochondrial swelling.

Main Results:

• Isoproterenol treatment increased heart weight/tibia length ratios and myocyte size, elevated H2O2 levels, and decreased glutathione peroxidase activity.
• Diazoxide administration blocked these isoproterenol-induced effects, an action reversed by 5-hydroxydecanoate.
• MitoKATP opening reduced Ca2+-induced mitochondrial swelling in hypertrophic hearts, an effect inhibited by 5-hydroxydecanoate.

Conclusions:

• MitoKATP opening effectively prevents isoproterenol-induced cardiac hypertrophy in vivo.
• This protective effect is mediated by the reduction of oxidative stress and prevention of mitochondrial damage, specifically Ca2+-induced swelling.
• Targeting mitoKATP represents a potential therapeutic strategy for managing pathological cardiac hypertrophy.