Abstract
Purpose :
Subconjunctival (SC) administration of AAV vectors exhibit capsid serotype-dependent transduction in the cornea and broad transduction of ocular/peri-ocular tissues, demonstrating its suitability to treat ocular diseases. In addition to viral capsid serotype and physiological factors, administration volume affect AAV vector transduction efficiency. Herein, we explored the role of administration volume in AAV gene delivery, biodistribution, and transduction efficiency following SC injection.
Methods :
The relationship between injection volume, vector transduction, and vector biodistribution was evaluated in wild type mice using multiple doses of self-complementary AAV8-CMV-GFP vectors. Sixty female C57BL/6J mice aged 6-8 weeks were randomly divided into no injection, low-volume (7 µl containing either 5e8 vg or 5e9 vg or vehicle), and high-volume (70 µl containing either 5e8 vg or 5e9 vg or vehicle) injection groups. Ocular clinical parameters were collected prior to and after the injections. Animals were sacrificed at 3 months following the injection and tissues were harvested for immunofluorescence staining, vector genome biodistribution and transgene expression analysis.
Results :
A single SC injection of AAV8 (7 µL), resulted in efficient transduction of the ocular muscles (Fig. 1); in contrast, a ten-fold higher injection volume of the same dose exhibited little to no detectable transduction in the ocular muscles, and trended towards higher transduction efficiency in the peripheral cornea (Fig. 2). The transduction pattern was a dose-independent phenomenon that correlated well with vector genome biodistribution.
Conclusions :
Taken together, the collective data indicate that injection volume dramatically alters AAV8 tissue transduction and biodistribution in the ocular and peri-ocular compartments following SC injection. Specifically, low-volume SC injection of AAV8 vectors could be ideal for therapy of ocular muscular diseases such as oculopharyngeal muscular dystrophy; Alternatively, AAV8 vectors administered in a high volume have apparent relevance for the treatment of ocular surface diseases including limbal stem cell deficiency and/or dry eye disease. Therefore, optimization of multiple experimental factors is necessary to achieve maximal transduction efficiency and desired tissue targeting, while concurrently decreasing vector production burden and immunological concerns.
This is a 2021 ARVO Annual Meeting abstract.