Effects of genetic transfection on calcium cycling pathways mediated by double-stranded adeno-associated virus in postinfarction remodeling.

Objective: Restoring calcium sensor protein (S100A1) activity in failing hearts poses a promising therapeutic strategy. We hypothesize that cardiac overexpression of the S100A1 gene mediated by a double-stranded adeno-associated virus (scAAV) results in better functional and molecular improvements compared with the single-stranded virus (ssAAV). Methods: Heart failure was induced by coronary artery ligation. Then, intramyocardial injections of saline, AAV9 empty capsid, scAAV9.S100A1, and ssAAV9.S100A1 were performed. Ten weeks postinfarction, all rats received cardiac evaluation; serum and tissue were collected for genetic analysis, cytokine profiling, and assessments of mitochondrial function and structure. Results: Overexpression of AAV9.S100A1 improved systolic and diastolic function. Compared with control, ejection fraction was greater in treated groups (54.8% vs 32.3%, P<.05). Similarly, end-diastolic volume index was significantly less in the treated group than in control (1.14 vs 1.59 mL/cm(2)), whereas fractional shortening was greater in treated groups than control (26% vs 38%, P<.05). Interestingly, cardiac mechanics were significantly better when treated with double-stranded virus compared with single-stranded. Quantitative polymerase chain reaction demonstrated robust transfection of myocardium with the S100A1 gene, with more infection in the self-complimentary group compared with the single-stranded group (5.68 +/- 0.44 vs 4.09 +/- 0.25 log(10) genome copies per 100 ng of DNA; P<.0001). Concentrations of the inflammatory cytokines were elevated in the ssAAV9/S100A1 group compared with the scAAV9/S100A1. Assessment of mitochondrial respiration and morphology demonstrated that injection of self-complementary vector saved both mitochondrial structure and function. Conclusions: Gene therapy of S100A1 can prevent pathologic postmyocardial infarction remodeling and decrease inflammatory response in ischemic heart failure.