Liquid jet delivery method featuring S100A1 gene therapy in the rodent model following acute myocardial infarction

Abstract

The S100A1 gene is a promising target enhancing contractility and survival post myocardial infarction (MI). Achieving sufficient gene delivery within safety limits is a major translational problem. This proof of concept study evaluates viral mediated S100A1 overexpression featuring a novel liquid jet delivery (LJ) method. Twenty-four rats after successful MI were divided into three groups (n = 8 ea.): saline control (SA); ssAAV9.S100A1 (SS) delivery; and scAAV9.S100A1 (SC) delivery (both 1.2 × 10¹¹ viral particles). For each post MI rat, the LJ device fired three separate 100 μl injections into the myocardium. Following 10 weeks, all rats were evaluated with echocardiography, quantitative PCR (qPCR) and overall S100A1 and CD38 immune protein. At 10 weeks all groups demonstrated a functional decline from baseline, but the S100A1 therapy groups displayed preserved left ventricular function with significantly higher ejection fraction %; SS group (60 ± 3) and SC group (57 ± 4) versus saline (46 ± 3), P < 0.05. Heart qPCR testing showed robust S100A1 in the SS (10,147 ± 3993) and SC (35,155 ± 5808) copies per 100 ng DNA, while off-target liver detection was lower in both SS (40 ± 40), SC (34,841 ± 3164), respectively. Cardiac S100A1 protein expression was (4.3 ± 0.2) and (6.1 ± 0.3) fold higher than controls in the SS and SC groups, respectively, P < 0.05.

Figure 1

A. The concept of liquid jet injection for cardiac gene therapy. A high pressurized jet of therapeutic is projected toward the epicardial surface of beating myocardium through a minimally invasive thoracotomy or as an adjunctive cardiac surgical procedure. Myocardial retention within safety limits can be optimized via parameter adjustment. B. The liquid jet delivery concept applied to the rodent model. The DERMOJet injector device mounted to a control arm for guidance of precise injections to the beating heart.

Figure 2

A. Gene therapy treatment groups demonstrate superior left ventricular performance via Ejection Fraction compared with saline and preserve more baseline function, * p<0.05, Baseline vs. 10 Week MI time point by group; ^† p<0.05, Saline Control group vs. both S100A1 groups at 10 Weeks Post MI. B. Gene therapy treatment groups demonstrate preserved left ventricular geometry via retained global LV wall thickness compared with Saline Control which deteriorated significantly from baseline, * p<0.05, Baseline vs. 10 Week MI time point by group.

Figure 3

Quantitative Poly Chain Reaction (QPCR) derived quantification of viral mediated S100A1 DNA. The SC vector performed significantly greater than the SS with much higher genome copies detected in both target cardiac and collateral liver organ tissues, * p<0.05.

Figure 4

A. Confocal microscopy image capture of typical myocardium with overexpression of S100A1 (orange-brown) featuring homogenous robust profile from the liquid jet injection methodology in the SS group, magnification 20×. B. A greater degree of S100A1 (orange-brown) overexpression featuring was confirmed in the SC group specimens, magnification 20×. C. Confocal microscopy image capture of typical myocardium with overexpression of S100A1 (orange-brown) featuring control level profile from the liquid jet injection methodology in the SA group, magnification 20×.

Figure 5

A. Quantitative immunofluorescence of therapeutic S100A1 protein demonstrates significantly higher target levels in both the SS and SC groups vs. Saline Control.* p<0.05, SS and SC groups vs. Saline Control; ^† p<0.05, SC vs. SS. B. Quantitative immunofluorescence of immune activator risk factor CD38 protein demonstrates significantly higher cardiac tissue levels in the SS and SC groups Saline vs. Control.* p<0.05, SS and SC groups vs. Saline Control; ^† p<0.05, SC vs. SS.