Diabetes abolish cardioprotective effects of remote ischemic conditioning: evidences and possible mechanisms

Area of Science:

• Cardiovascular Physiology
• Metabolic Disease Research
• Cellular Signaling Mechanisms

Background:

• Diabetes mellitus is known to compromise the heart's ability to protect itself from ischemic injury.
• Remote ischemic conditioning (RIC) typically activates protective pathways, but this response is blunted in diabetic individuals.
• Understanding the molecular basis of this impairment is crucial for developing therapeutic strategies.

Purpose of the Study:

• To review the mechanisms by which diabetes mellitus attenuates the cardioprotective effects of remote ischemic conditioning (preconditioning, postconditioning, and perconditioning).
• To elucidate the role of impaired signaling pathways, oxidative stress, and altered cellular processes in diabetic hearts.
• To consolidate current knowledge on the molecular dysfunctions that reduce RIC-induced cardioprotection in diabetes.

Main Methods:

• This is a review article, synthesizing existing research findings.
• Analysis of studies investigating signaling pathways such as O-GlcNAc, ERK, PI3K/AKT, mTOR, and AMPK.
• Examination of the impact of diabetes on oxidative stress, autophagy, nitric oxide bioavailability, and related enzymes.

Main Results:

• Diabetes impairs O-linked β-N-acetylglucosamine (O-GlcNAc) signaling and the release of cardioprotective factors.
• Key signaling proteins like ERK, PI3K, AKT, and AMPK show altered phosphorylation patterns, while mTOR is upregulated.
• Diabetes increases oxidative stress (ROS), inhibits autophagy, reduces nitric oxide (NO) bioavailability, and increases Rho-kinase (ROCK) activity, collectively diminishing cardioprotection.

Conclusions:

• Diabetes significantly attenuates remote ischemic conditioning-induced cardioprotection by disrupting multiple molecular pathways.
• Impaired signaling cascades, increased oxidative stress, and reduced autophagy are central to this loss of protection.
• Targeting these specific pathways may offer novel therapeutic avenues to restore cardioprotection in diabetic patients.