Abstract 18026: Pro-angiogenic Dual Gene Therapy in Chronic Diabetic Hindlimb Ischemia with Ultrasound Mediated Delivery of miR-126 and VEGF Plasmid DNA
Background: MicroRNA (miR)-126 is an endothelial cell specific microRNA that regulates angiogenesis by blocking Sprouty-related protein (SPRED1) and phosphoinositol-3 kinase (PI3K) two endogenous inhibitors of VEGF signalling. In diabetes, the circulating level of miR-126 is decreased and may contribute to defective angiogenesis.
Hypothesis: Dual ultrasound-mediated gene delivery (UMGD) of miR-126 and VEGF plasmid DNA will improve microvascular blood flow (MBF) of chronic ischemia in diabetes.
Methods: In vitro: Human umbilical vascular endothelial cells (HUVECs) were transfected with scramble miR or miR-126 with non-transfected cells as controls. 1x104 cells were plated in growth factor enriched matrigel. The capillary-like network formation was captured in photomicrographs for quantification. In vivo: Unilateral hindlimb ischemia was created by left femoral artery ligation in Zucker Diabetic fatty (ZDF) rats. Blood samples were analyzed for circulating levels of miR-126 and blood glucose levels. At day 14 post-ligation, MBF was assessed by contrast-enhanced ultrasound (CEU) followed by ultrasound-mediated gene delivery (UMGD) of either 1) miR-126 (2.5 mcg), 2) VEGF plasmid DNA (500 mcg) or 3) miR-126 + VEGF plasmid DNA, with 4) control animals receiving no treatment (n=4-6 per group). CEU-derived MBF was re-assessed at day 28.
Results: In vitro: The number of nodes formed by the HUVECs transfected with miR-126 were higher than both control and scramble groups (p<0.05; miR-126 vs scramble and control). In vivo: ZDF animals had high blood glucose levels (>30 mmol/L) and ~40% reduction of circulating miR-126 levels compared to non-diabetic Zucker lean animals. At 14 days post-ligation surgery, MBF of the ischemic leg was reduced by ~50% compared to the contralateral leg. At day 28 (14 days post delivery), the MBF of miR-126 delivered animals was improved with greatest improvement observed in the miR-126 and VEGF dual delivered animals (~80% MBF of non-ischemic contralateral leg). MBF of control animals remained at baseline levels of 50% at day 28.
Conclusion: Dual UMGD of miR-126 and VEGF plasmid DNA increased MBF in chronic hindlimb ischemia in ZDF rats, and may be an effective technique for therapeutic angiogenesis in the setting of diabetes.
Author Disclosures: W.J. Cao: None. P.N. Matkar: None. H.H. Chen: None. Y.J. Kim: None. D. Rudenko: None. M. Kuliszewski: None. H. Leong-Poi: None.
- © 2014 by American Heart Association, Inc.