Prevascularized grafts with spatially organized MSC spheroids to accelerate therapeutic angiogenesis in ischemic...

Ischemic diseases, characterized by impaired blood flow and progressive tissue necrosis, remain a major challenge in regenerative medicine. Surgical revascularization remains the gold standard for restoring blood flow in major vessels, but still shows limited effects on microvascular regeneration. To address this unmet need, various strategies in therapeutic angiogenesis have been explored to induce microvascular formation, including delivery of bioactive molecules, stem cells, or pre-vascularized grafts. However, injection-based approaches often suffer from off-target effects, and conventional implantable grafts lack sufficient angiogenic secretory activity. To address these limitations, we aimed to develop a dual-function prevascularized graft that accelerates neovascularization and promotes vascular integration to restore tissue perfusion in ischemic conditions.

The graft was engineered by combining a microvascular pattern (µVP) with spatially organized mesenchymal stem cell (MSC) spheroids, fabricated via high-precision coprinting of endothelial cells and MSCs. Optimization of spheroid density and spatial arrangement enhanced VEGF secretion and increased host capillary infiltration nearly two-fold. In a murine critical limb ischemia model, implantation of these engineered grafts achieved a 60% limb salvage rate and reduced limb loss by ~ 15%, representing a 4.5-fold improvement over conventional grafts. Histological and morphometric analyses confirmed reduced muscle degeneration, enhanced neovascularization, and seamless anastomosis between engineered and host vessels.

These findings demonstrate a dual-functional graft that couples paracrine stimulation with structural vascular support, providing a promising regenerative strategy to promote therapeutic angiogenesis and ischemia therapy, while indicating its potential for preclinical and future clinical applications in ischemic disease.