Transfection with a dominant-negative inhibitor of monocyte chemoattractant protein-1 gene improves cardiac function after 6 hours of cold preservation

Background-Monocyte chemoattractant protein-1 (MCP-1), a potent chemotactic factor for monocytes, is induced during ischemia-reperfusion. As monocytes might play an important causative role in reperfusion injury, we investigated if inhibition of monocyte activation could attenuate ischemia-reperfusion injury and thereby improve cardiac preservation. To inhibit monocyte activation, we transfected a dominant-negative inhibitor of MCP-1 (7ND) gene in an animal model. Methods and Results-We used an isolated rabbit heart preparation perfused with support-rabbit blood and transfected 7ND genes to skeletal muscle of the support rabbits (n=7) using electroporation technique; causing an elevation of serum 7ND level to 20+/-7 pg/mL at 5 days after transfection. Animals receiving empty plasmid served as controls (n=7). Five days after transfection, hearts from other rabbits were excised, stored in UW solution for 6 hours, and perfused with blood from transfected support rabbits. The 7ND group showed better cardiac output (128.7+/-17.9 versus 81.6+/-19.8 mL/min; P<0.01), lower serum CK-MB levels (5.0±1.8 versus 11.1±2.9 ng/mL; P<0.01), lower serum IL-1beta levels (257.2+/-23.2 versus 311.2+/-37.4 pg/mL; P<0.05), and lower serum TNF-α levels (19.0±8.4 versus 35.1±13.0 pg/mL; P<0.05). The numbers of infiltrating cells in myocardium were significantly reduced in the 7ND group. Conclusions-Inhibition of MCP-1 with 7ND gene transfection reduced cytokine activation, attenuated myocardial damage, and improved cardiac function after 6 hours of preservation. These results show that MCP-1 plays an important role in ischemia-reperfusion injury.