Evaluation of multimeric tyrosine-O-sulfate as a cytoprotectant in an in vivo model of acute myocardial infarction in pigs.

OBJECTIVES Intracoronary administration of glycosaminoglycan analogs, including the complement inhibitor dextran sulfate, attenuates myocardial ischemia/reperfusion injury (I/R injury). However, dextran sulfate has a distinct anticoagulatory effect, possibly limiting its use in specific situations in vivo. We therefore developed multimeric tyrosine sulfate (sTyr-PAA), a novel, minimally anticoagulatory, fully synthetic non-carbohydrate-containing polyacrylamide conjugate, for in vivo testing in an acute closed-chest porcine model of acute myocardial infarction. METHODS Following balloon occlusion of the left anterior descending artery just after the first diagonal branch (60-minute ischemia), sTyr-PAA (approx. 10 mg/kg bodyweight, fraction with strongest complement-inhibitory and minimal anticoagulatory properties, n = 11) or phosphate-buffered saline (controls, n = 9) was administered intracoronarily into ischemic myocardium prior to 120 min of reperfusion. RESULTS sTyr-PAA significantly reduced infarct size (from 61.0 ± 12.0% of the ischemic area at risk to 39.4 ± 17.0%), plasma creatine kinase, local complement deposition and tissue factor upregulation, without affecting systemic coagulation. Protection was associated with significantly reduced myocardial neutrophil extravasation and translated into a significant improvement of ejection fraction and left ventricular enddiastolic pressure. CONCLUSIONS sTyr-PAA protected significantly against myocardial I/R injury without substantially affecting systemic coagulation. Local intravascular sTyr-PAA administration may prove advantageous in situations where bleeding complications are likely or are to be avoided at all costs.