Perfluorochemical liquid enhances adeno-associated virus-mediated transgene expression in lungs

Use of adeno-associated virus (AAV) vectors for lung gene therapy is limite d, in part, by low levels of AAV-mediated transgene expression in lungs. Ge nerally, less than 1% of total airway and alveolar epithelial cells express transgene activity following vector administration. A means of improving A AV vector delivery could potentially enhance AAV-mediated gene expression i n lungs. We have previously demonstrated that use of perfluorochemical (PFC ) liquids improved overall levels of adenovirus vector-mediated gene expres sion as well as distribution of expression in lungs of spontaneously breath ing rodents. To evaluate whether use of PFC liquids might similarly enhance AAV-mediated expression, spontaneously breathing rodents received intratra cheal instillation of the AAV vectors CWRAP and ARAP4 (2-5 x 10(8) FFU/anim al) with or without 10 cc/kg body wt PFC liquid (FC-75, ACROS). Animals wer e sacrificed 4 weeks later and lungs assessed for overall and in situ alkal ine phosphatase (AP) expression. Animals receiving vector alone exhibited s cattered sparse in situ activity, predominantly in alveolar epithelium. In contrast, animals receiving vector with FC-75 exhibited increased and more widespread AP expression as well as up to a 26-fold increase in AP activity . These results demonstrate that use of the PFC liquid FC-75 improves overa ll and in situ AAV-mediated gene expression in rodent lungs.