| Rampant inflammation, excessive oxidative stress, and senescence are processes that plague many pathological conditions such as vascular restenosis or non-healing diabetic ulcers. Consequently, strategies that modulate all of these events during the early stages of vascular or dermal wound healing are crucial to inhibiting restenosis and accelerating healing in diabetic ulcers. Sirtuin 1 (Sirt1), an NAD+-dependent lysine deacetylase, is intrinsically linked to regulating energy metabolism, DNA repair, stress response, senescence, and apoptosis. The downregulation or dysfunction of Sirt1 is associated with pathologies such as atherosclerosis, diabetic vascular dysfunction, and impaired wound healing.;In this dissertation, we explore whether Sirt1 overexpression via lentiviruses encoding for Sirt1 (LV-Sirt1) in adventitial fibroblasts, an active participant in vascular remodeling, is protective against inflammatory activation, oxidative stress, and senescence. Sirt1-overexpressing adventitial fibroblasts have significantly higher lysine deacetylase activity, and upon TNF&agr; stimulation, NFkappaB activity and cytokine expression/secretion levels were significantly decreased. Furthermore, Sirt1 overexpression attenuated p53 activity, prevented cellular senescence, and increased catalase expression. In our preliminary study using a rat carotid artery balloon injury model, perivascular treatment with LV-Sirt1 resulted in Sirt1 overexpression at the adventitia and demonstrated changes suggestive of improved vessel wall remodeling.;This work also exploits advancements in gene delivery that have supported combinatorial approaches to deliver gene vectors from biomaterials for localized transgene expression. We investigate the utility of poly(polyethyleneglycol citrate-co-N-isopropylacrylamide (PPCN), a degradable, temperature-responsive material, as a vehicle for lentiviral vector delivery. PPCN undergoes a thermo-reversible transition that does not damage the incorporated lentiviral vector, supports cell ingrowth, and can be applied for perivascular and subcutaneous transgene delivery.;Finally, this dissertation lays the groundwork of LV-Sirt1 delivered from PPCN for diabetic dermal wound healing applications. Using an excisional skin wounding diabetic model, wound closure rate was significantly faster with PPCN+LV-Sirt1 treatment compared to PPCN. Furthermore, PPCN+LV-Sirt1 treatment had less dermal fibrosis, less inflammation, and faster regeneration of pilosebacious units. In summary, our results suggest that Sirt1 may be a therapeutic target to enhance healing in diabetic ulcers and improve vascular remodeling, and that PPCN can serve as a novel in situ gelation material to deliver gene vectors. |
