Key result
Pre-ischemic irisin reduces myocardial infarct size by an absolute ~13% and improves functional recovery.
Why the study?
The functional role of irisin in modulating cardiac ischemia and reperfusion injury has not been defined.
Absolute Event Rate: 36.04% vs 48.85%
p-value: p=<0.05
May suggest irisin preconditioning benefit in isolated hearts; hypothesis-generating and requires in vivo confirmation before any clinical consideration.
Ventricular performance and coronary flow in Langendorff perfused rat hearts were measured over a wide range of perfusion pressures and heart rates. A change in aortic pressure from 60 to 120 mmHg induced a linear increase in coronary flow, ventricular systolic pressure, and contractility. Ventricular pacing from 300 to 600 beats/min under a constant afterload had no effect on coronary flow. Systolic pressure remained stable up to 400-450 beats/min and then decreased 14% at 600 beats/min compared to the nonpaced controls. When contraction rate exceeded 450 beats/min diastolic pressure progressively increased as the heart rate was elevated. Contractility decreased rapidly between 450 and 600 beats/min under all perfusion pressures. These data indicate that this heart model is physiologically stable with heart rates less than 450 beats/min and may be useful in studying tachycardia-induced work overload.
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Taylor et al. (1976) studied Myocardial ischemia and reperfusion injury. Irisin vs. Vehicle (saline) or no treatment was evaluated on Myocardial infarct size as a percentage of risk area (p=<0.05). Irisin treatment administered prior to ischemia significantly reduced myocardial infarct size from 48.85% to 36.04% and improved post-ischemic ventricular functional recovery compared to vehicle.
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