LDLR and steatosis: Transient mild liver injury following hydrodynamic injection has previously been observed by other groups.24 This transient effect may be the result of elevated intravascular pressure caused by the sheer force of injection which expands the liver fenestrae to generate transient pores in the plasma membrane of hepatocytes.25 No steatosis was visible from Oil Red O staining of liver sections from Ldlr -/- mice delivered with the therapeutic plasmids after 3 months postdelivery.