MCARD-mediated gene transfer of GRK2 inhibitor in ovine model of acute myocardial infarction

Abstract

β-Adrenergic receptor (βAR) dysfunction in acute myocardial infarction (MI) is associated with elevated levels of the G-protein-coupled receptor kinase-2 (GRK2), which plays a key role in heart failure progression. Inhibition of GRK2 via expression of a peptide βARKct transferred by molecular cardiac surgery with recirculating delivery (MCARD) may be a promising intervention. Five sheep underwent scAAV6-mediated MCARD delivery of βARKct, and five received no treatment (control). After a 3-week period, the branch of the circumflex artery (OM1) was ligated. Quantitative PCR data showed intense βARKct expression in the left ventricle (LV). Circumferential fractional shortening was 23.4 ± 7.1 % (baseline) vs. -2.9 ± 5.2 % (p < 0.05) in the control at 10 weeks. In the MCARD-βARKct group, this parameter was close to baseline. The same trend was observed with LV wall thickening. Cardiac index fully recovered in the MCARD-βARKct group. LV end-diastolic volume and LV end-diastolic pressure did not differ in both groups. MCARD-mediated βARKct gene expression results in preservation of regional and global systolic function after acute MI without arresting progressive ventricular remodeling.

Figure 1

A. Baseline cardiac MRI featuring End diastolic (EDD) and End systolic (ESD) dimensions B. Control group (10 weeks) cardiac MRI featuring End diastolic (EDD and End systolic dimensions with infarct zone (MI, yellow) C. MCARD-βARKct group (10 weeks) cardiac MRI featuring End diastolic and End systolic dimensions with infarct zone (MI,yellow) D. Delayed Enhancement MRI: Myocardial Infarct Characterization E. Histological Confirmation of Myocardial Infarction Size

Figure 1

A. Baseline cardiac MRI featuring End diastolic (EDD) and End systolic (ESD) dimensions B. Control group (10 weeks) cardiac MRI featuring End diastolic (EDD and End systolic dimensions with infarct zone (MI, yellow) C. MCARD-βARKct group (10 weeks) cardiac MRI featuring End diastolic and End systolic dimensions with infarct zone (MI,yellow) D. Delayed Enhancement MRI: Myocardial Infarct Characterization E. Histological Confirmation of Myocardial Infarction Size

Figure 1

A. Baseline cardiac MRI featuring End diastolic (EDD) and End systolic (ESD) dimensions B. Control group (10 weeks) cardiac MRI featuring End diastolic (EDD and End systolic dimensions with infarct zone (MI, yellow) C. MCARD-βARKct group (10 weeks) cardiac MRI featuring End diastolic and End systolic dimensions with infarct zone (MI,yellow) D. Delayed Enhancement MRI: Myocardial Infarct Characterization E. Histological Confirmation of Myocardial Infarction Size

Figure 2

A: RT-qPCR of βARKct expression in the heart and collateral organs in MCARD-βARKct group at 10 weeks. B: Western blot: βARKct proten biodistribution in the heart and collateral organs in MCARD-βARKct group at 10 weeks. βARKct referenced to GAPDH standard control. C: Image of Western blot: βARKct proten biodistribution in the heart and collateral organs

Figure 2

A: RT-qPCR of βARKct expression in the heart and collateral organs in MCARD-βARKct group at 10 weeks. B: Western blot: βARKct proten biodistribution in the heart and collateral organs in MCARD-βARKct group at 10 weeks. βARKct referenced to GAPDH standard control. C: Image of Western blot: βARKct proten biodistribution in the heart and collateral organs

Figure 3

A: Left ventricular fractional wall shortening in the myocardial infarct area at baseline, control group (10 weeks) and MCARD-βARKct group (10 weeks) * p<0.05 control vs.baseline; † p<0.05 MCARD-βARKct group vs. control group. B: Left ventricular transmural wall thickening of the myocardial infarct area at a baseline, control group (10 weeks) and MCARD-βARKct groups (10 weeks) * p<0.05 baseline vs. control group; † p<0.05 MCARD-βARKct group vs. control group

Figure 4

A: Cardiac index at baseline, control group (10 weeks) and MCARD-βARKct group (10 weeks) * p<0.05 baseline vs. control group; † p<0.05 MCARD-βARKct group vs. control group B: Stroke volume index at baseline, control group (10 weeks) and MCARD-βARKct group (10 weeks) * p<0.05 baseline vs. control group; † p<0.05 MCARD-βARKct group vs. control group

Figure 5

A: Left ventricular end diastolic volume index at baseline, control group (10 weeks) and MCARD-βARKct group (10 weeks) * p<0.05 baseline vs. control group and MCARD-βARKct group. B: Left ventricular end diastolic pressure at baseline, control group (10 weeks) and MCARD-βARKct group (10 weeks) * p<0.05 baseline vs. control group and MCARD-βARKct group.

Figure 6

Average cross sectional cardiac myocyte area in the infarct borderzone * p<0.05 control group (10 weeks) vs. MCARD-βARKct group (10 weeks)