1008-OR: Endothelial Metallothionein Enables VEGF Therapy in Diabetic Ischemic Wound Healing

Introduction and Objective: Pressure ulcer remain a significant clinical burden among hospitalized, mobility-compromised diabetic patients such as bedsores and DFU. Vascular impairment restricts the perfusion of ischemic wounds. Increased oxidative stress, inadequate vessel maturation, and systemic adverse effects have collectively undermined the clinical efficacy of Vascular endothelial growth factor (VEGF) therapy. To determine whether a targeted molecular modulator can improve VEGF responsiveness, this study aims to identify the novel molecular patterns to improve the therapeutic outcomes. Methods: Endothelial heterogeneity in human diabetic skin (36, 487 cells) was characterized by single-cell RNA sequencing (scRNA-Seq). Non-viral tissue nanotransfection (TNT) enabled endothelial-targeting delivery of CDH5 promoter-drive shRNAs targeting metallothionein (MT) in murine ischemic limb and pressure ulcer models. Vascular integrity was evaluated by immunohistochemistry and Matrigel assay was employed to assess the angiogenic activity. ROS generation and translational studies are examined by Flow cytometry and immunoblotting, respectively. Results: Despite largely preserved VEGF signaling in the diabetic skin, scRNA-seq and CellChat analyses revealed a marked suppression of five MT isoforms (MT2A, MT1E, MT1X, MT1M, MT1A). Similarly, MT expressions were also observed in wound-edge endothelial diabetic mice. Endothelial MT knockdown elevated the oxidative stress and suppressed angiogenesis, demonstrated by decreased vWF+/CD31+ vascular elements. TNT-mediated MT enhancement restored VEGF responsiveness and significantly improved ischemic tissue rescue by suppressing ROS through the MT1/2 → SOD1 axis. Conclusion: Endothelial metallothionein is essential for VEGF-driven angiogenesis in diabetic ischemic wounds. Hyperglycaemia-induced endothelial cells suppress the VEGF efficacy. TNT-based topically induced MT promotes a strategy to overcome VEGF resistance and enhance perfusion in diabetic ischemic wounds. Disclosure P. Katiyar: None. S.S. Verma: None. D. Pandey: None. A. Sahi: None. C. Sen: None. K. Singh: None.