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Cardioplegia and diazoxide modulate STAT3 activation and DNA binding
Yng-Ju Hsieh1, Hidetaka Wakiyama, Sidney Levitsky
1Division of Cardiothoracic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Harvard Institutes of Medicine, Boston, Massachusetts 02115, USA.
The Annals of Thoracic Surgery
|September 25, 2007
Summary
Diazoxide addition to cardioplegia significantly reduces heart cell death after ischemia by enhancing STAT3 signaling. This improves myocardial protection during cardiac surgery.
Area of Science:
- Cardiovascular Science
- Molecular Biology
- Surgical Research
Background:
- Magnesium-supplemented potassium (DSA) cardioplegia and DSA with diazoxide (DSA+DZX) reduce apoptosis post-ischemia.
- The cardioprotective mechanism involving signal transducers and activators of transcription (STATs) was previously unelucidated.
- This study investigated the impact of DSA and DSA+DZX on STAT1/3 phosphorylation and DNA binding.
Purpose of the Study:
- To determine the effect of DSA and DSA+DZX cardioplegia on STAT1 and STAT3 phosphorylation and DNA binding.
- To elucidate the role of STAT signaling in myocardial protection offered by these cardioplegic solutions.
Main Methods:
- Utilized an in situ blood-perfused pig heart model with induced regional ischemia via left anterior descending coronary artery occlusion.
- Administered DSA or DSA+DZX cardioplegia during cardiopulmonary bypass, followed by ischemia and reperfusion.
- Analyzed tissue samples using Western blot and electrophoretic mobility shift assay to assess STAT phosphorylation and DNA binding.
Main Results:
- Ischemia increased proapoptotic STAT1 phosphorylation, more so in the regional ischemia zone.
- STAT3 phosphorylation and DNA binding were altered by ischemia, with decreased antiapoptotic STAT3 activity in the regional zone correlating with increased apoptosis.
- DSA+DZX significantly enhanced antiapoptotic STAT3 phosphorylation and DNA binding in the regional ischemia zone, concurrently reducing apoptosis.
Conclusions:
- Diazoxide addition to DSA cardioplegia significantly reduces myocardial apoptosis.
- This cardioprotection is mediated by increased STAT3 phosphorylation and DNA binding.
- DSA+DZX represents a promising strategy for enhanced myocardial protection during cardiac procedures.
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