Modified VEGF-A mRNA induces sustained multifaceted microvascular response and accelerates diabetic wound healing

Abstract

Capable of mediating efficient transfection and protein production without eliciting innate immune responses, chemically modified mRNA holds great potential to produce paracrine factors at a physiologically beneficial level, in a spatiotemporally controlled manner, and with low toxicity. Although highly promising in cardiovascular medicine and wound healing, effects of this emerging therapeutic on the microvasculature and its bioactivity in disease settings remain poorly understood. Here, we longitudinally and comprehensively characterize microvascular responses to AZD8601, a modified mRNA encoding vascular endothelial growth factor A (VEGF-A), in vivo. Using multi-parametric photoacoustic microscopy, we show that intradermal injection of AZD8601 formulated in a biocompatible vehicle results in pronounced, sustained and dose-dependent vasodilation, blood flow upregulation, and neovessel formation, in striking contrast to those induced by recombinant human VEGF-A protein, a non-translatable variant of AZD8601, and citrate/saline vehicle. Moreover, we evaluate the bioactivity of AZD8601 in a mouse model of diabetic wound healing in vivo. Using a boron nanoparticle-based tissue oxygen sensor, we show that sequential dosing of AZD8601 improves vascularization and tissue oxygenation of the wound bed, leading to accelerated re-epithelialization during the early phase of diabetic wound healing.

Opportunities and Challenges in the Delivery of mRNA-Based Vaccines

“…vaccination of patients with type 2 diabetes [108]. However, in spite of pronounced, sustained, dose-dependent and cargo-specific vasodilation, blood flow increase, oxygen-metabolic upregulation, angiogenesis and neovessel formation in animal models, the vasodilatory and angiogenic activity did not translate into humans [108,109]. Microneedle-based delivery is also an efficient technique where micron-sized needle patch/arrays composed of water-soluble polymeric or sugar excipients are employed, into which the mRNA is incorporated [76].…”

Synthetic mRNA Encoding VEGF-A in Patients Undergoing Coronary Artery Bypass Grafting: Design of a Phase 2a Clinical Trial

“… 29 Injection of AZD8601 also enhanced blood flow and increased blood vessel density in the skin and heart in animal models. 28 , 29 Furthermore, epicardial injection of AZD8601 improved cardiac function in pigs following experimental myocardial infarction. 29 …”

“…AZD8601 is a clinical-grade VEGF-A 165 mRNA formulated in biocompatible citrate-buffered saline and optimized for efficient VEGF-A protein production with minimal induction of innate immune responses. 28 , 29 , 30 AZD8601 injection elicits sustained transient expression of functional VEGF-A protein in the skin, heart, and skeletal muscle in animal models, 28 , 29 , 30 with no apparent acute toxicity or inflammation in rats and cynomolgus monkeys. 29 Injection of AZD8601 also enhanced blood flow and increased blood vessel density in the skin and heart in animal models.…”

“…Functional VEGF-A protein expression after injection of AZD8601 was demonstrated in a first-in-human phase 1 trial, consistent with findings in animal models. 28 , 29 , 30 , 31 Sustained increases in local blood flow were detected in both humans and animals following intradermal AZD8601 injections, together with transient local production of VEGF-A protein. 28 , 29 , 30 , 31 AZD8601 promoted new blood vessel formation in animal models and improved cardiac function in a pig model of myocardial infarction.…”

“… 28 , 29 , 30 , 31 Sustained increases in local blood flow were detected in both humans and animals following intradermal AZD8601 injections, together with transient local production of VEGF-A protein. 28 , 29 , 30 , 31 AZD8601 promoted new blood vessel formation in animal models and improved cardiac function in a pig model of myocardial infarction. 28 , 29 , 30 Furthermore, AZD8601 did not induce innate immune responses in animals and was well tolerated in human volunteers, with minimal local reactions.…”