The size of sinusoidal fenestrae is a critical determinant of hepatocyte transduction after adenoviral gene transfer

The hepatotropism and intrahepatic distribution of adenoviral vectors may be species dependent. Hepatocyte transduction was evaluated in three rabbit strains after transfer with E1E3E4-deleted adenoviral vectors containing a hepatocyte specific alpha(1)-antitrypsin promoter-driven expression cassette (AdAT(4)). Intravenous administration of 4 x 10(12) particles/kg of AdAT(4) induced human apo A-I levels above 40 mg/dl in Dutch Belt, but below 1 mg/dl in New Zealand White and Fauve de Bourgogne rabbits. Diameters of sinusoidal fenestrae were significantly ( P = 0.0014) larger in Dutch Belt (124 +/- 3.4 nm) than in New Zealand White (108 +/- 1.3 nm) and Fauve de Bourgogne (105 +/- 2.6 nm) rabbits, suggesting that a smaller size constitutes a barrier for hepatocyte transduction. Indeed, intraportal transfer preceded by intraportal injection of sodium decanoate, which increases the diameter of sinusoidal fenestrae to 123 +/- 3.4 nm ( P<0.01) in New Zealand White rabbits, increased human apo A-I levels 32- and 120-fold in New Zealand White and Fauve de Bourgogne rabbits, respectively, but did not affect expression in Dutch Belt rabbits. In conclusion, size of sinusoidal fenestrae appears to be a critical determinant of hepatocyte transduction after adenoviral transfer.