Positive effect of darbepoetin on peri-infarction remodeling in a porcine model of myocardial ischemia–reperfusion

doi:10.1016/j.yjmcc.2007.05.014

Journal of Molecular and Cellular Cardiology

Volume 43, Issue 2, August 2007, Pages 130-136

https://doi.org/10.1016/j.yjmcc.2007.05.014 Get rights and content

Abstract

Erythropoietin (Epo) has anti-apoptotic and pro-angiogenic effects in rodent models of myocardial infarction (MI). We tested the hypothesis that a long-acting Epo derivative (darbepoetin) has a beneficial effect on infarct size and peri-infarct remodeling in a clinically relevant large animal model of ischemia–reperfusion. A human acute MI scenario was simulated in 16 domestic pigs by inflating an angioplasty balloon in the proximal left circumflex (LCx) artery for 60 min. The animals were randomized to darbepoetin 30 μg/kg iv or placebo (saline) at the time of reperfusion. Treatment with darbepoetin did not lead to a reduction in the infarct size at 2 weeks as assessed by histology (30.3 ± 1.8% of the volume at risk for placebo vs. 33.2 ± 2.5% for darbepoetin). However, significant effects were seen in the peri-infarct region. Histological evaluation revealed decreased interstitial fibrosis (6.8 ± 0.7% of myocardial sections area vs. 9.6 ± 0.7%, p = 0.02) and increased average capillary area (106 ± 3% of the non-infarcted myocardium vs. 89 ± 4%, p = 0.003) in the treatment arm in the absence of significant cardiac hypertrophy. This resulted in preserved regional wall motion as assessed by tissue Doppler-derived radial strain (subepicardial radial strain 90.1 ± 21.2% for darbepoetin vs. 20.3 ± 10.1% for placebo, p < 0.05). However, this did not translate to improved wall thickening (126.5 ± 6.0% of diastolic thickness for darbepoetin vs. 119.8 ± 5.4% for placebo, p = NS). Beneficial effects of darbepoetin to peri-infarct remodeling were observed in a clinically relevant model of ischemia–reperfusion. Although the infarct size was not reduced, there was a limited decrease in interstitial fibrosis, increased capillary area and regional functional improvement in darbepoetin-treated animals.

Section snippets

Background

Abrupt occlusion of a coronary artery initiates a cascade of events beginning with hypoxic cell death, followed by prolonged adverse remodeling over a period of weeks, with subsequent systolic dysfunction. This process involves both apoptosis of the cardiac cells and increased cardiac fibrosis [1] as well as rearrangement of myocardial fibers [2]. Although early restoration of flow remains the best strategy at limiting infarct size, apoptotic cell death continues secondary to reperfusion

Porcine model of ischemia–reperfusion

Male crossbred farm pigs (20–30 kg, n = 16) were used in this study. All experiments were done in accordance with the University of Pittsburgh institutional guidelines. The pigs were sedated, intubated and anesthesia was provided using 1.5% inhaled isoflurane. The animals received 300 mg aspirin rectally and amiodarone iv (30 mg bolus, followed by infusion at 1 mg/min) to prevent the lethal ventricular arrhythmias associated with this model. Arterial access was obtained by placing 6 French sheath

Myocardial infarction model

There were 5 deaths in total (31%, 4 in the placebo group and 1 in the darbepoetin group, p = NS); all the observed mortality occurred within 24 h following the myocardial infarction and was likely due to ventricular arrhythmias. The final analysis includes 6 animals in the treatment arm and 5 in the control arm. At 2 weeks, there was no significant increase in the hemoglobin in the treated animals (10.8 ± 0.7 g/dl at baseline vs. 11.3 ± 0.6 g/dl at 2 weeks); similarly, the white cell and platelet

Discussion

Our results indicate that darbepoetin administration at the time of reperfusion did not lead to a chronic reduction in infarct size, but had a positive remodeling effect in the surviving myocardium bordering the scar.

Previous rodent data demonstrate a significant reduction of the scar with erythropoietin, even when administered after the acute event [5], [6], [9], [10], [11], [12]. In large animals, as well as in our study, the effects are less robust. Hirata and colleagues showed that Epo

Acknowledgments

We would like to thank David Fischer for his excellent assistance with the animal procedures and to Kimberly Fuhrer and Lisa Chedwick for their expert assistance with histology. This work was supported by a grant from Amgen Inc., Thousand Oaks, CA.

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Biodegradable elastic patch plasty ameliorates left ventricular adverse remodeling after ischemia-reperfusion injury: A preclinical study of a porous polyurethane material in a porcine model
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The left main coronary artery was selectively engaged using an AL 1 guide catheter (6F; Cordis Corp., Miami, Fla). Using a 3.5 × 12 mm coronary dilatation balloon catheter (Guidant, Santa Clara, Calif), the proximal left circumflex artery was occluded for 60 minutes by balloon inflation (Figure 1).16 Direct-current cardioversion was performed when sustained ventricular tachycardia or ventricular fibrillation was observed.
Myocardial infarction (MI) can lead to irreversible adverse left ventricular remodeling resulting in subsequent severe dysfunction. The objective of this study was to investigate the potential for biodegradable, elastomeric patch implantation to positively alter the remodeling process after MI in a porcine model.
Yorkshire pigs underwent a 60-minute catheter balloon occlusion of the left circumflex artery. Two weeks after MI animals underwent epicardial placement of a biodegradable, porous polyurethane (poly(ester urethane)urea; PEUU) patch (MI+PEUU, n = 7) or sham surgery (MI+sham, n = 8). Echocardiography before surgery and at 4 and 8 weeks after surgery measured the end-diastolic area (EDA) and fractional area change (%FAC). All animals were humanely killed 8 weeks after surgery and hearts were histologically assessed.
At 8 weeks, echocardiography revealed greater EDA values in the MI+sham group (23.6 ± 6.6 cm², mean ± standard deviaation) than in the MI+PEUU group (15.9 ± 2.5 cm²) (P < .05) and a lower %FAC in the MI+sham group (24.8 ± 7.6) than in the MI+PEUU group (35.9 ± 7.8) (P < .05). The infarcted ventricular wall was thicker in the MI+PEUU group (1.56 ± 0.5 cm) than in the MI+sham group (0.91 ± 0.24 cm) (P < .01).
Biodegradable elastomeric PEUU patch implantation onto the porcine heart 2 weeks post-MI attenuated left ventricular adverse remodeling and functional deterioration and was accompanied by increased neovascularization. These findings, although limited to a 2-month follow-up, may suggest an attractive clinical option to moderate post-MI cardiac failure.
Intracoronary administration of darbepoetin-alpha at onset of reperfusion in acute myocardial infarction: Results of the randomized Intra-Co-EpoMI trial
2013, Archives of Cardiovascular Diseases
Citation Excerpt :
Optimal protection was manifest at a dose of 2.5 μg/kg. In a clinically relevant porcine model of ischemia-reperfusion, intravenous administration of a larger dose of DA (30 μg/kg) 5 minutes prior to reperfusion led to increased capillary density, decreased interstitial fibrosis and significant regional functional improvement despite a lack of reduction in the IS [14]. In the first pilot clinical study, Lipsic et al. demonstrated that one bolus of DA 300 μg administered intravenously before primary PCI was safe and well tolerated [24].
Several trials investigating erythropoietin as a novel cytoprotective agent in myocardial infarction (MI) failed to translate promising preclinical results into the clinical setting. These trials could have missed crucial events occurring in the first few minutes of reperfusion. Our study differs by earlier intracoronary administration of a longer-acting erythropoietin analogue at the onset of reperfusion.
To evaluate the ability of intracoronary administration of darbepoetin-alpha (DA) at the very onset of the reperfusion, to decrease infarct size (IS).
We randomly assigned 56 patients with acute ST-segment elevation MI to receive an intracoronary bolus of DA 150 μg (DA group) or normal saline (control group) at the onset of reflow obtained by primary percutaneous coronary intervention (PCI). IS and area at risk (AAR) were evaluated by biomarkers, cardiac magnetic resonance (CMR) and validated angiographical scores.
There was no difference between groups regarding duration of ischemia, Thrombolysis in Myocardial Infarction flow grade at admission and after PCI, AAR size and extent of the collateral circulation, which are the main determinants of IS. The release of creatine kinase was not significantly different between the two groups even when adjusted to AAR size. Between 3–7 days and at 3 months, the area of hyperenhancement on CMR expressed as a percentage of the left ventricular myocardium was not significantly reduced in the DA group even when adjusted to AAR size.
Early intracoronary administration of a longer-acting erythropoietin analogue in patients with acute MI at the time of reperfusion does not significantly reduce IS.
Plusieurs essais qui ont étudié l’érythropoïétine (EPO) comme un nouvel agent protecteur lors de l’infarctus du myocarde (IDM), ont échoué à traduire en clinique les études précliniques prometteuses. Ces essais pourraient avoir laissé de côté des évènements cruciaux au cours des premières minutes de la reperfusion. Notre étude diffère par une administration plus précoce, intracoronaire d’une EPO à longue durée d’action, au moment de la reperfusion.
L’objectif de cet essai était d’évaluer l’intérêt de la darbépoétine-alpha (DA) intracoronaire administrée précocement à la reperfusion pour diminuer la taille de l’IDM.
Nous avons randomisé 56 patients avec IDM aigu avec sus-élévation du segment ST, pour recevoir soit un bolus intracoronaire de 150 μg de darbépoétine-alpha (groupe DA) ou du sérum physiologique (groupe témoin) au moment de la reperfusion obtenue par angioplastie primaire (PCI). L’aire à risque et la taille de l’infarctus ont été évalués par des biomarqueurs, une imagerie par résonance magnétique (IRM) et des scores angiographiques validés.
Il n’y avait pas de différence entre les deux groupes en termes de durée d’ischémie, de flow TIMI à l’admission et après angioplastie, d’aire à risque ou encore de collatéralité, qui sont les principaux déterminants de la taille de l’infarctus. La libération de CK n’était pas significativement différente entre les deux groupes même après ajustement sur la taille de l’aire à risque. Après trois à sept jours et à trois mois, l’aire du rehaussement à l’IRM exprimée comme un pourcentage du ventricule gauche n’était pas significativement réduit dans le groupe DS, même après ajustement sur l’aire à risque.
L’administration précoce intracoronaire d’une EPO de longue durée d’action chez de patients avec IDM aigu, au moment de la reperfusion ne réduit pas significativement la taille de l’IDM.
Angiogenic effects of erythropoietin
2012, International Review of Cell and Molecular Biology
Erythropoietin (Epo) is a low-molecular weight glycoprotein hormone stimulator of erythropoiesis synthesized in the fetal liver and in the adult kidney. Moreover, Epo is a pleiotropic cytokine that exerts diverse biological effects in non-hematopoietic tissues, and angiogenesis is indicated as one of its extra-hematopoietic functions. The involvement of Epo in angiogenesis may be considered as subset of its role in improving overall tissue oxygenation and of its anti-apoptotic role. In this context, Epo may be considered as an endogenous stimulator of vessel growth during tumor progression, and inhibition of Epo signaling might be suggested as a new antiangiogenic therapeutic approach. It is conceivable suppose that the effect of Epo is multifactorial, depending on the type of tumor and level of functionality of Epo receptor expression in tumor cells, as well as on other variables, such as hypoxic stress and degree of anemia.
The effect of intravenous administration of erythropoietin on the infarct size in primary percutaneous coronary intervention
2011, International Journal of Cardiology
Citation Excerpt :
In the ischemia–reperfusion model of dog, intravenous treatment of rhEPO before reperfusion was led to decreased infarct size and lower incidence of ventricular fibrillation by modulating signal pathways such as akt and ERK1/2 [21]. However, administration of erythropoietin immediately before ischemia or at reperfusion had no effect on the infarct size in pig and sheep models [3,22–24]. The observed discrepancy between large animal and rodent data may be related to differences in myocardial perfusion between models.
After an acute myocardial infarction, the early restoration of coronary blood flow is mandatory for reducing infarct size. However, the process of reperfusion itself may also cause irreversible myocardial injury and contribute to the final infarct size. Recent animal studies have suggested that erythropoietin could protect the myocardium when administered after the onset of reperfusion. We investigated whether the administration of erythropoietin at the time of PCI would limit the size of the infarct during acute myocardial infarction by analysis of MRI and cardiac enzymes in this pilot study.
We randomly assigned 57 patients with acute, anterior wall ST-elevation myocardial infarction who were presented within 12 h after the onset of chest pain to one group which was given an intravenous bolus of recombinant human erythropoietin (rhEPO, 50 U/kg) immediately before undergoing PCI or the control group without the IV treatment before PCI. Infarct size was assessed by measuring the release of cardiac enzymes (CK, CK-MB) and by performing MRI on day 4 after infarction.
The injection of erythropoietin did not result in thrombotic or hypertensive complications. The release of cardiac enzyme was not different between two groups. On day 4, the absolute infarct volume of the area of hyperenhancement on MRI did not differ between two groups (EPO group 52.4 ± 23.6 cm³ vs. control group 54.8 ± 28.6 cm³, p = 0.74). Two groups did not differ in the percentage of total infarct volume over left ventricle volume (EPO group 34.4 ± 11.7% vs. 37.0 ± 13.8%, p = 0.50).
Intravenous administration of erythropoietin was safe and was not associated with thrombotic or hypertensive side effects. However, it did not reduce the infarct size when assessed by MRI and cardiac enzyme. Further studies about the dose or routes of administration of EPO are needed (ClinicalTrials.gov Identifier NCT00882466).
Cytokine combination therapy with long-acting erythropoietin and granulocyte colony stimulating factor improves cardiac function but is not superior than monotherapy in a mouse model of acute myocardial infarction
2010, Journal of Cardiac Failure
Erythropoietin (EPO) and granulocyte colony stimulating factor (GCSF) are potential novel therapies after myocardial infarction (MI). We first established the optimal and clinically applicable dosages of these drugs in mobilizing hematopoietic stem cells (HSC), and then tested the efficacy of monotherapy and combination therapy post-MI.
Optimal doses were established in enhanced green fluorescent protein (eGFP) + chimeric mice (n = 30). Next, mice underwent MI and randomized into 4 groups (n = 18/group): 1) GCSF; 2) EPO; 3) EPO+GCSF; and 4) control. Left ventricular (LV) function was analyzed pre-MI, at 4 hours and at 28 days post-MI. Histological assessment of infarct size, blood vessels, apoptotic cardiomyocytes, and engraftment of eGFP+ mobilized cells were analyzed at day 28. LV function in the control group continued to deteriorate, whereas all treatments showed stabilization. The treatment groups resulted in less scarring, increased numbers of mobilized cells to the infarct border zone (BZ), and a reduction in the number of apoptotic cardiomyocytes. Both EPO groups had significantly more capillaries and arterioles at the BZ.
We have established the optimal doses for EPO and GCSF in mobilizing HSC from the bone marrow and demonstrated that therapy with these agents, either as monotherapy or combination therapy, led to improvement of cardiac function post-MI. Combination therapy does not seem to have additive benefit over monotherapy in this model.
Pathogenesis of myocardial ischemia-reperfusion injury and rationale for therapy
2010, American Journal of Cardiology
Citation Excerpt :
Erythropoietin, for instance, is currently being investigated in clinical studies99–101 of acute MI, after the discovery of erythropoietin receptor expression in the myocardium.102 Erythropoietin has antiapoptotic activity103,104 and positive effects on remodeling,105–107 and it recruits endothelial progenitor cells.108 It is hoped that this drug may exert positive effects by more than 1 of these pathways.
Since the initial description of the phenomenon by Jennings et al 50 years ago, our understanding of the underlying mechanisms of reperfusion injury has grown significantly. Its pathogenesis reflects the confluence of multiple pathways, including ion channels, reactive oxygen species, inflammation, and endothelial dysfunction. The purposes of this review are to examine the current state of understanding of ischemia-reperfusion injury, as well as to highlight recent interventions aimed at this heretofore elusive target. In conclusion, despite its complexity our ongoing efforts to mitigate this form of injury should not be deterred, because nearly 2 million patients annually undergo either spontaneous (in the form of acute myocardial infarction) or iatrogenic (in the context of cardioplegic arrest) ischemia-reperfusion.

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Original articlePositive effect of darbepoetin on peri-infarction remodeling in a porcine model of myocardial ischemia–reperfusion

Abstract

Section snippets

Background

Porcine model of ischemia–reperfusion

Myocardial infarction model

Discussion

Acknowledgments

J. Am. Coll. Cardiol.

Kidney Int.

J. Am. Soc. Echocardiogr.

J. Am. Soc. Echocardiogr.

J. Am. Coll. Cardiol.

J. Biol. Chem.

Microvasc. Res.

J. Am. Coll. Cardiol.

Blood

J. Am. Coll. Cardiol.

Structural basis of end-stage failure in ischemic cardiomyopathy in humans

Circulation

Remodelling in the myocardium adjacent to an infarction in a pig left ventricle

Am. J. Physiol.

New avenues of exploration for erythropoietin

JAMA

Recombinant human erythropoietin protects the myocardium from ischemia–reperfusion injury and promotes beneficial remodeling

Proc. Natl. Acad. Sci. U. S. A.

Original article
Positive effect of darbepoetin on peri-infarction remodeling in a porcine model of myocardial ischemia–reperfusion