97. Focal Gene Delivery in the Murine Lymphedema Tail Model Using Tissue Nanotransfection Technology (TNT)

Abstract

Background: Lymphedema is chronic limb swelling resulting from lymphatic dysfunction. It affects an estimated 5 million Americans. There is no cure for this disease. Experimental gene-based therapeutic approaches (e.g., using viral vectors) have had limited translational applicability. Tissue nanotransfection technology (TNT) utilizes a direct, transcutaneous non-viral vector, gene delivery using a chip with nanochannel poration in a rapid (<100ms) focused electric field. This platform technology has been used for various applications in tissue reprogramming. The ability to deliver genetic cargo at a focal, non-global site would have practical clinical potential in lymphedema treatment. The purpose of this study is to experimentally evaluate the applicability of TNT for lymphedema. Methods: The murine tail model of lymphedema was utilized. A 3 mm full thickness skin excision and lymphatic vessel disruption was performed 20 mm from the base of the tail in twelve C57BL/6 mice. TNT was applied to the murine tail (day 0) directly at the surgical site with genetic cargo loaded into the TNT reservoir: Group I (control) was given pCMV6 (expression vector backbone alone) (n=6); Group II had pCMV6-Prox1 (n=6). TNT was applied with square wave pulse electric stimulation (10x10ms pulses, 250 V, 10 mA). The efficiency of gene delivery was assessed through qRT-PCR using primers with SYBR Green fluorescence quantification and immunostaining with anti-Prox1 antibody. Results: The experimental Group II exhibited four-fold increased expression of Prox1 using qRT-PCR compared to control Group I at the site of TNT treatment (P<0.05). Increased expression of Prox1 was also observed with immunohistochemistry 3 days post-TNT application. Intensity quantification of immunohistochemistry revealed greater expression of Prox1 in Group II when compared to Group I (P<0.05). Conclusion: This study demonstrates a novel, focal nanotechnology approach for local genetic cargo delivery in murine tail lymphedema model without the use of viral vectors for transfection. TNT can rapidly and effectively be applied for potentially therapeutic delivery of factors locally at the site of lymphedema.