Cardiovascular Research Advance Access first published online on April 20, 2009
This version [Corrected Proof] published online on May 14, 2009
Cardiovascular Research, doi:10.1093/cvr/cvp122
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Parstatin: a cryptic peptide involved in cardioprotection after ischaemia and reperfusion injury
1 Division of Cardiovascular Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, USA
2 Department of Pharmacology, Medical School, University of Patras, Rio-Patras, Greece
3 Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
4 Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, USA
* Corresponding author. Tel: +1 414 456 8895; fax: +1 414 453 9700. E-mail address: jstrande{at}mcw.edu
Aims: Thrombin activates protease-activated receptor 1 by proteolytic cleavage of the N-terminus. Although much research has focused on the activated receptor, little is known about the 41-amino acid N-terminal peptide (parstatin). We hypothesized that parstatin would protect the heart against ischaemia–reperfusion injury.
Methods and results: We assessed the protective role of parstatin in an in vivo and in vitro rat model of myocardial ischaemia–reperfusion injury. Parstatin treatment before, during, and after ischaemia decreased infarct size by 26%, 23%, and 18%, respectively, in an in vivo model of ischaemia–reperfusion injury. Parstatin treatment immediately before ischaemia decreased infarct size by 65% and increased recovery in ventricular function by 23% in an in vitro model. We then assessed whether parstatin induced cardioprotection by activation of a Gi-protein-dependent pathway. Gi-protein inactivation by pertussis toxin completely abolished the cardioprotective effects. The cardioprotective effects were also abolished by inhibition of nitric oxide synthase (NOS), extracellular signal-regulated kinases 1/2 (ERK1/2), p38 mitogen-activated protein kinase (p38 MAPK), and KATP channels in vitro. Furthermore, parstatin increased coronary flow and decreased perfusion pressure in the isolated heart. The vasodilatory properties of parstatin were confirmed in rat coronary arterioles.
Conclusion: A single treatment of parstatin administered prior to ischaemia confers immediate cardioprotection by recruiting the Gi-protein activation pathway including p38 MAPK, ERK1/2, NOS, and KATP channels. Parstatin exerts effects on both the cardiomyocytes and the coronary circulation to induce cardioprotection. This suggests a potential therapeutic role of parstatin in the treatment of cardiac injury resulting from ischaemia and reperfusion.
KEYWORDS Cryptic peptide; Cardioprotection; Ischaemia; Reperfusion injury; Vasodilation
Time for primary review: 21 days