COLLAGEN-CCN1 MATRIX FOR THE TREATMENT OF MYOCARDIAL INFARCTION

Abstract

Cardiac remodeling and subsequent heart failure remain critical issues following myocardial infarction (MI). CCN1 is a pro-angiogenic matricellular protein that has been shown to induce fibroblast senescence and restrict fibrosis during wound healing. Herein, we test the hypothesis that injection of a collagen matrix containing CCN1 will attenuate adverse cardiac remodeling and improve function in a mouse MI model. One week after LAD ligation, mice were randomized to receive intramyocardial injections of PBS, CCN1 (in PBS), matrix, or CCN1-matrix, administered under echocardiographic guidance. Function was evaluated up to 4 weeks post-MI by echocardiography. At 1-wk post-treatment, significant improvements in LVEF were observed for both the CCN1 (48.1±3.3%) and CCN1-matrix (41.9±3.5%) treated groups compared to PBS (34.6±2.8%; p<0.03). By 4 weeks, LVEF was superior in CCN1-matrix treated hearts (49.7±2.1%) compared to PBS (28.9±2.9%), CCN1 (38.0±2.6%) and matrix (38.7±1.6%) groups (p<0.01). In vitro evaluation revealed a protective effect of the CCN1-matrix on cultures of neonatal cardiomyocytes as there was a 39.3% increase in cell survival under stress conditions compared to matrix-cultured cardiomyocytes (p=0.03). The in vitro culture of fibroblasts on the CCN1-matrix resulted in a 2.3±0.7 and 1.6±0.2 fold reduction in proliferation compared to fibroblasts cultured on tissue culture polystyrene (TCPS; p=0.008) and matrix (p=0.04), respectively. Furthermore, the collagenase activity of CCN1-matrix cultured fibroblasts was reduced compared to both TCPS- and matrix-cultured fibroblasts. Circulating angiogenic cells (CACs) responded to CCN1-matrix treatment with a 2.2±0.2 fold increase in proliferation and a 1.8±0.2 fold increase in migration towards VEGF compared to matrix (p=0.001) cultured CACs. In an angiogenic assay, CCN1-matrix cultured CACs demonstrated a 4.1±1.6 fold increase in cell incorporation into capillary-like structures (p=0.03) and a 5.1±0.6 fold increase in overall tubule network formation (p=0.007), compared to matrix-cultured CACs. Here, we demonstrate a novel approach to treat MI using a CCN1-containing collagen biomaterial. The functional benefits achieved with CCN1 treatment persisted for the 4 weeks only when it was delivered with the matrix. These data suggest that CCN1-matrix improves cardiac function in the MI heart by reducing fibrosis and promoting neovascularization and cardiomyocyte survival.