Heart-homing peptide

FVB (2-month old, male, 20-25 g)^[1]

7 mg/kg; 20 mg/kg; 60 mg/kg

i.v.; single dose

Achieved 47-fold greater fluorescence in cardiac tissue surrounding vascular lumens than non-targeted liposomes and 64-fold greater than free dye within 30 minutes of 20 mg/kg injection.
Increased tissue, endothelial, and punctate fluorescence intensities from 7 mg/kg to 20 mg/kg, with no further increase at 60 mg/kg, indicating saturation of accumulation and trans-endothelial transport.
Maintained cardiac fluorescence intensity at ~40% of the 30-minute value at 24 hours post-injection, which was significantly greater than control groups.
Detected fluorescence above non-treated controls in 37.0% of endothelial (CD31+) cells, 0.63% of cardiomyocytes (MF20+), and 5.3% of fibroblasts (Thy1.1+) at 4 hours post-injection of 60 mg/kg liposomes.
Detected fluorescence above non-treated controls in 29.1% of endothelial (CD31+) cells, 0.80% of cardiomyocytes (MF20+), and 4.0% of fibroblasts (Thy1.1+) at 12 hours post-injection of 60 mg/kg liposomes.

C57BL/6 (10-week-old male, TAC-induced pressure overload)^[3]

4 mg/kg

i.v.; every third day; 7 doses total

Accumulated at nearly double the mean fluorescence intensity in mouse hearts 24 hours post-single intravenous administration compared to non-targeted exosomes.
Significantly ameliorated TAC-induced reductions in left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) at days 28 and 42 post-TAC, and significantly improved left ventricular end-systolic volume (LVV.s), diastolic left ventricular anterior wall thickness (LVAW.d), systolic left ventricular anterior wall thickness (LVAW.s), and left ventricular mass compared to PBS controls.
Reversed TAC-induced mean arterial blood pressure elevation from 116.70 mmHg to 92.37 mmHg.
Significantly reduced serum levels of angiotensin II (Ang II) and N-terminal pro B-type natriuretic peptide (NT-proBNP), and lung wet/dry weight ratio compared to PBS controls.
Significantly reduced TAC-induced increases in heart/body weight ratio, heart weight/tibial length ratio, and relative cardiomyocyte surface area (increased by 30% in PBS-treated TAC mice).
Significantly reduced TAC-induced upregulation of hypertrophic marker genes Acta1, Nppa, Nppb, and the Myh7/Myh6 ratio, and significantly decreased perivascular and myocardial interstitial fibrosis from 19.49% and 16.88% in PBS-treated TAC mice to 2.43% and 1.13%.
Significantly reduced TAC-induced upregulation of hypertrophy-associated proteins β-MHC, BNP, GP130, p-ERK1/2, p-AKT, and p-STAT3 in ventricular tissues.
Restored TAC-induced reduction in cardiac miRNA-148a levels to 252.30% of sham levels (vs.
66.83% in PBS-treated TAC mice).