Angiotensin-(1-7) improves the post-ischemic function in isolated perfused rat hearts

Area of Science:

• Cardiovascular Physiology
• Renal Physiology
• Pharmacology

Background:

• The renin-angiotensin system plays a crucial role in cardiovascular regulation.
• Angiotensin-(1-7) (Ang-(1-7)) is a bioactive peptide with known cardiovascular effects.
• Ischemia-reperfusion injury is a major cause of myocardial damage.

Purpose of the Study:

• To evaluate the protective effects of Ang-(1-7) on post-ischemic cardiac function.
• To investigate the underlying mechanisms of Ang-(1-7)-mediated cardioprotection.

Main Methods:

• Isolated adult male Wistar rat hearts were perfused using the Langendorff technique.
• Myocardial ischemia was induced by coronary ligation (15 min), followed by reperfusion (30 min).
• Hearts were treated with Ang-(1-7), Angiotensin II (Ang II), or specific antagonists (A-779, HOE 140, indomethacin, L-NAME).

Main Results:

• Ang-(1-7) (0.22 nM) prevented the reduction in systolic tension during reperfusion after ischemia.
• Ang II did not offer the same protective effect.
• The cardioprotective effect of Ang-(1-7) was blocked by A-779 and HOE 140, and indomethacin, but not L-NAME.

Conclusions:

• Low-concentration Ang-(1-7) significantly improves myocardial systolic tension following ischemia-reperfusion.
• The protective mechanism involves Ang-(1-7) receptors, bradykinin B2 receptors, and prostaglandin release.
• Ang-(1-7) demonstrates potential as a therapeutic agent for mitigating cardiac ischemia-reperfusion injury.