Percent difference in reduction in alamarBlue activity of rat cardiac endothelial cells in response to hydrogen peroxide with and without iECM, relative to controls with no hydrogen peroxide (a, n=6 both groups, **p=0.006). Percent viability as measured by Calcein-AM staining of rat cardiac endothelial cells in response to hydrogen peroxide with and without iECM, relative to controls with no hydrogen peroxide (b, n=4 both groups, ***p<0.001). Concentration of hydrogen peroxide was monitored following incubation with either PBS or iECM, showing a continuing decrease with iECM (c, *p=0.01, **p=0.003, n=3 for both groups at 1 and 24 hrs, n=2 at 6 hrs). Thiol content was determined compared to N-acetylcysteine standard in iECM per mg of material (d, n=3). Data are mean ± SEM. All data are biological replicates and were evaluated with a two tailed unpaired t-test.