Targeted delivery controlled release of hepatic growth factor and insulin-like growth factor-1 improves left ventricular repair in a porcine model of myocardial ischemia reperfusion injury

Introduction

Nanomedicine offers great potential for treatment of cardiovascular disease. We tested whether direct intramyocardial (IM) injection of pro-angiogenic hepatocyte growth factor (HGF) and pro-myogenic insulin-like growth factor (IGF-1) encapsulated in Alginate-Sulfate nanoparticles (AlgS-NP) enhances myocardial retention, controlled release and improves myocardial repair in a porcine ischemia-reperfusion model.

Methods

Bioactivity of HGF/IGF, released from AlgS-NP, was determined by cell proliferation assays in vitro. Myocardial infarction (MI) was induced by 75min balloon occlusion of the mid-LAD followed by reperfusion. After 1w, pigs (n=12) with marked LV dysfunction (EF<45%) were randomized to fusion imaging-guided IM injections of 8 mg Cy5-labelled AlgS-NP loaded with 200μg HGF and 200μg IGF-1 (GF) or with phosphate-buffered saline (CON) using the MYOSTAR injection catheter. AlgS-NP retention after IM or intracoronary (IC) injection was determined by measuring Cy5 plasma levels. At 8w, treatment effect was evaluated using in vivo magnetic resonance imaging and coronary physiological measurements, and via post-mortem analysis of myocardial fibrosis and cardiomyocyte circumference.

Results

We confirmed the bioactivity of the AlgS-NP-released GF in C2C12 and HUVEC cell proliferation assays after 72h culture, being similar to the free GF (Fig. A). AlgS-NP retention was tested in a pig model, 1w after MI. Ejection fraction (EF) was 37±5% (range 27–45%) and infarct size (IS)/LVmass 24±6% (range 19–38%). AlgS-NP retention was better after IM delivery than after IC infusion with plasma Cy5 levels at 30 min after treatment indicating 5% systemic leakage for IM vs. 20% for IC. After 8w, IS/LVmass decreased 8% in GF-treated pigs vs. 3% in CON (P=0.03, Fig. B) and was associated with preserved myocardial blood flow during hyperemia in the infarct (P=0.036) and peri-infarct (PI) zones (P=0.008), increased coronary flow reserve (P=0.05) and decreased index of microcirculatory resistance (P=0.02). LVEF significantly increased in GF-treated pigs (+6±2% vs. −1±1% in CON, P=0.02, Fig. C), and was accompanied by significantly reduced fibrosis (P=0.01) and increased hypertrophy of cardiomyocyte (P=0.03) in the PI zone.

Conclusions

IM injection of AlgS-NP-encapsulated HGF and IGF-1 to the ischemic myocardium significantly improves LV repair, and offers the prospect of innovative treatment for patients with refractory ischemic heart disease.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EuroNanoMed II Figure AFigure B and C

Clec4e signalling influences left-ventricular functional recovery in a murine model of myocardial ischemia-reperfusion injury

Introduction

The acute inflammatory response contributes substantially to functional recovery and remodelling of the left ventricle after acute ischemic injury. Previously, we have shown that the C-Type Lectin Receptor CLEC4E plays a role in early leukocyte recruitment during the acute inflammatory response of ischemia-reperfusion injury (I/R). However, the role of CLEC4E signalling in functional recovery of the left ventricle after I/R remains unknown. Therefore, we studied the chronic inflammatory response and left-ventricular remodelling in murine gene deletion model of Clec4e, subjected to I/R.

Methods

In anesthetized C57Bl6/J wild-type (n=14) and Clec4e−/− (n=13) mice, we transiently occluded the left-descending artery for 60 min, followed by 4 weeks reperfusion (I/R). A blood sample was collected at 90 minutes reperfusion to measure high-sensitivity troponin I (TnI) levels, as a surrogate marker of cardiac damage. At 4 weeks, mice underwent MRI (7T) to investigate the effect of Clec4e-gene deletion on LV-remodelling.

Results

Plasma TnI-levels showed no statistical difference between both groups, indicating that the initial insult was comparable. In wild-type mice, plasma TnI-levels negatively correlated with ejection fraction (EF, R2=0.92 p<0.0001) at 4 weeks I/R, while Clec4e−/− mice showed preserved EF, irrespective of 90 minutes TnI-levels. MRI-analysis at 4 weeks after I/R showed significantly smaller end-diastolic and end-systolic volumes in Clec4e−/− mice, together with a trend towards a higher ejection fraction, suggesting better preserved structural and functional LV-remodelling (Fig.1).

Conclusion

The inflammatory leukocyte-associated Clec4e signalling pathway impairs functional recovery of the left ventricle after myocardial I/R injury. Inhibition of the Clec4e receptor may be a promising strategy in the treatment of ischemic injury.

Figure 1

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Scholarship Ir. Jozef en Mevr. Reinhilde De Swerts 2018-2022 by the Royal Academy of Medicine of Belgium

Nanoparticles loaded with hepatic growth factor and insulin-like growth factor-1 improve left ventricular repair in a porcine model of myocardial Ischemia reperfusion injury

Introduction

Nanomedicine offers great potential for treatment of cardiovascular disease. We tested whether intramyocardial (IM) injection of pro-angiogenic hepatocyte growth factor (HGF) and anti-apoptotic, pro-myogenic insulin-like growth factor 1 (IGF-1) encapsulated in Alginate-Sulfate nanoparticles (AlgS-NP) improves left ventricular (LV) functional recovery in a porcine ischemia-reperfusion (I/R) model.

Methods

Myocardial infarction (MI) was induced by 75min balloon occlusion of the mid-LAD followed by reperfusion. After 1w, pigs (n=12) with marked LV dysfunction (EF<45%) were randomized to fusion imaging-guided IM injections of 8 mg Cy5-labelled AlgS-NP loaded with 200μg HGF and IGF-1 (GF) or with phosphate-buffered saline (CON) using the MYOSTAR injection catheter. AlgS-NP retention in the heart was determined by measuring Cy5 levels in peripheral blood. At 8w, treatment effect was evaluated using cardiac magnetic resonance imaging and coronary flow reserve (CFR) measurements, and further assessed using sirius red staining to measure myocardial fibrosis.

Results

At 1w after MI, LV ejection frqction (LVEF) was 37±5% (range 27–45%) and infarct size (IS)/LV mass 24±6% (range 19–38%). Myocardial retention of AlgS-NP was comparable between 2 groups (maximal systemic leakage after IM injection: 9% CON vs 20% GF, P=0.25). After 8 w, IS/LV mass decreased by one third in GF-treated pigs compared with 14% in CON (P=0.03, Fig. A) and was associated with a trend towards improvement in CFR (P=0.05, Fig. B). LVEF significantly increased in GF-treated pigs (6±2% vs. −1±1%, P=0.02, Fig. C), which was attributable to a greater reduction in end-systolic volume. The improvement in LVEF was also consistent with significant reduction of fibrosis (P=0.01, Fig. D) in the peri-infarct zone (PI).

Conclusions

Intramyocardial injection of AlgS-nanoparticle-encapsulated HGF and IGF-1 to the ischemic myocardium significantly improves LV repair, and offers the prospect of innovative treatment for patients with refractory ischemic heart disease.

Funding Acknowledgement

Type of funding source: Public grant(s) – EU funding. Main funding source(s): EuroNanoMed, Horizon 2020