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Updated: Aug 19, 2026
Postconditioning with Lactate-enriched Blood for Cardioprotection in ST-segment Elevation Myocardial Infarction
Published on: May 28, 2019
Pharmacological preconditioning with monophosphoryl lipid A improves post ischemic diastolic function and modifies
Ram Sharony1, Inna Frolkis, Dvir Froylich
1Department of Cardiothoracic Surgery, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, 6 Witzman St., Tel Aviv 64239, Israel. sharonyn@netvision.net.il
Objective:
Pharmacologic preconditioning represents an attractive myocardial protection strategy. Tumor necrosis factor-alpha plays an important role in myocardial ischemia-reperfusion injury. We aimed to determine the effect of Monophosphoryl lipid A-induced delayed preconditioning on diastolic and systolic left ventricular function and tumor necrosis factor-alpha synthesis during ischemia and reperfusion.
Methods:
Rats (n=10) were pretreated with Monophosphoryl lipid A (350 microg/kg) or vehicle (n=9). Twenty-four hours later, the hearts were isolated and perfused on a Langendorff apparatus. Hemodynamic measurements, tumor necrosis factor-alpha mRNA expression and protein content were studied after stabilization (baseline), after 35 min of global ischemia and at 40 min of reperfusion.
Results:
Left ventricular developed pressure and peak rate of left ventricular developed pressure (dP/dt) rise were comparable between the animals in the control and Monophosphoryl lipid A treated groups during baseline but were higher in Monophosphoryl lipid A group at reperfusion (74+/-4 vs 51+/-5 mmHg, 3340+/-172 vs 2240+/-156 mmHg/s, respectively, P<0.01). dP/dt fall was significantly lower in the MLA group (2630+/-225v 1580+/-210 mmHg/s, P<0.01) at 40 min of reperfusion as well as end diastolic pressure. Baseline tumor necrosis factor-alpha mRNA (expressed as arbitrary densitometry units) were higher in the Monophosphoryl lipid A group (1.3+/-0.1 vs 0.5+/-0.03, P<0.05) but remained constant after ischemia and reperfusion (1.3+/-0.1 and 1.4+/-0.03, P=0.2), while further increase was observed in the control group (from 1.0+/-0.1 to 1.4+/-0.1, P<0.05). Tumor necrosis factor-alpha protein content from heart effluent in the control group was increased during reperfusion (79+/-30 and 200+/-22pg/ml, P<0.05) but was undetectable in the Monophosphoryl lipid A group. Marked TNF-alpha immunostaining of left ventricular tissue was observed only in the control group but no TNF-alpha staining was evident in the Monophosphoryl lipid A treated group at 40 min of reperfusion.
Conclusion:
Monophosphoryl lipid A-induced preconditioning renders the heart more tolerant to ischemia-reperfusion in terms of left ventricular diastolic and systolic function, and prevents tumor necrosis factor-alpha production during ischemia, through aborting the translation phase of tumor necrosis factor-alpha synthesis.
