Prevention of Post-Surgical Lymphedema using Tissue Nanotransfection Technology

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Project Summary Lymphedema is chronic limb swelling from lymphatic dysfunction which affects 250 million people worldwide. It is estimated that 5-10 million Americans have lymphedema, and 250 million people are affected worldwide Secondary lymphedema occurs most commonly following surgical management of solid tumors (e.g., breast cancer, melanoma). Axillary lymph node dissection (ALND) is performed for locally advanced breast cancer or biopsy-proven metastases to the axillary nodes and results in lymphedema in 30% of patients post-operatively. Skin thickening, interstitial fluid retention, and fibroadipose subcutaneous deposition from inflammation result in progressive limb enlargement. Lymphedema impacts quality of life and has a high health cost burden. Morbidity includes recurrent cellulitis, pain, and impaired extremity function. Non-surgical management of lymphedema includes compression therapy. Surgical treatment involves excisional (e.g, skin/subcutaneous resection) and microsurgical physiologic procedures including vascularized lymph node transfer and lymphovenous bypass. Current treatments may improve limb size and symptoms, but do not cure lymphedema. Progressive limb enlargement from the inflammatory manifestations is difficult to reverse. A preventative surgical strategy termed Immediate Lymphatic Reconstruction (ILR) has recently emerged in attempt to decrease the frequency of lymphedema. Afferent lymphatics in the axilla that have been disrupted during lymph node removal are microsurgically anastomosed to adjacent veins. ILR decreases the lymphedema occurrence to 9% after lymphadenectomy. However, broad applicability of preventative ILR is limited as it requires specialized equipment, technical expertise, prolongs operative time, and is performed in select centers. Viral vector-based gene strategies to upregulate lymphangiogeneis have had limited clinical translational applicability. Viral vectors can cause global lymphangiogenesis at unintended sites. Tissue nanotransfection technology (TNT) has been developed for in vivo tissue reprogramming. TNT facilitates direct, transcutaneous gene delivery using a silicon chip fabricated with nanochannels in a rapid (<100ms) focused electric field. The feasibility of TNT for gene delivery has been established and validated for other applications in animal models. We propose a novel, innovative approach to use TNT for non-surgical, focal gene delivery at the time of lymphatic injury to the murine tail model of lymphedema to stimulate lymphangiogenesis to prevent lymphatic dysfunction. In Aim 1, TNT will be used for prophylactic gene delivery of Prox1, a master regulator of lymphatic development which controls lymphatic endothelial progenitor cells and regulates lymphangiogenesis. Lymphatic function and lymphangiogenesis will be rigorously assessed. In Aim 2, we will determine the effects of TNT-delivered genes on inflammation using RNA-seq analysis and cytokine assays to lead to more precise targets. Prophylactic lymphedema microsurgery (ILR) has evolved the surgical treatment paradigm of lymphedema. This exploratory proposal on lymphedema prevention will have high translational significance and adaptability.