We demonstrate that the efficiency of adenovirus-assisted exogenous Ca 2+ ATPase (SERCA) and reporter (EGFP) gene expression is much higher in primary cultures of myocytes from neonatal rat hearts, than in primary cultures of myocytes from adult rat hearts. In this respect, the neonatal myocytes behave similarly to the established COS-1 cell line. This difference is related to the level of coxsackie adenovirus receptor (CAR) that affects cell penetration and expression level of exogenous genes, and explains variations in the observed consequences of exposure to adenovirus vector carrying SERCA cDNA. Awareness of these differences should be highly advantageous in complementary studies of exogenous gene expression in neonatal and adult myocytes. It should also be advantageous in evaluating conditions yielding optimal ratios of functional benefits over possible toxic effects upon exogenous SERCA gene delivery to cardiac muscle.
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