Standard heparin, low molecular weight heparin, low molecular weight heparinoid, and recombinant hirudin differ in their ability to inhibit transduction by recombinant adeno-associated virus type 2 vectors

Recombinant adeno-associated virus type 2(rAAV) is a promising vector for i n vivo gene therapy. Transduction by rAAV requires binding to heparan sulfa te proteoglycan on the cell surface, and heparin can block this binding. Be cause heparin is administered to most patients undergoing cardiovascular ge ne transfer in order to prevent thrombotic events, if is important to ident ify anticoagulants which do not interfere with rAAV transduction. Therefore , we examined the influence of different anticoagulants on rAAV transductio n in vitro, rAAV transduction was inhibited by 40.5 +/- 7.9% at heparin con centrations of 0.1 U/ml, and by 81.7 +/- 3.6% at 1.0 U/ml. The low molecula r weight (LMW) heparin tinzaparin inhibited rAAV transduction by 20.2 +/- 3 .8% at 0.1 U/ml and 37.1 +/- 1.8% at 1.0 U/ml. The inhibitory effect was si gnificantly weaker compared with heparin at 1.0 U/ml, (P < 0.01). The LMW h eparinoid danaparoid inhibited rAAV transduction by 8.8 +/- 3.5% at 0.1 U/m l (P < 0.01 compared with heparin). In contrast, recombinant hirudin did no t interfere at all with rAAV transduction. In summary, the results demonstr ate that inhibition of rAAV transduction by heparin occurs rapidly and at t herapeutically used concentrations. LMW heparinoids and above all recombina nt hirudin might be alternatives for heparin when vascular gene transfer wi th rAAV requires transient anticoagulation.