Enhanced Neovascularization Using Injectable and rhVEGF-Releasing Cryogel Microparticles

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Cryogels offer tunable properties like injectability and shape-memory for biomedical applications.
• Growth factors are crucial for stimulating tissue repair and regeneration, particularly neovascularization.

Purpose of the Study:

• To develop and evaluate an injectable cryogel microparticle (CMP) system for sustained release of recombinant human vascular endothelial growth factor (rhVEGF).
• To investigate the therapeutic efficacy of rhVEGF-loaded CMPs (V-CMPs) in promoting neovascularization and preventing tissue necrosis.

Main Methods:

• Fabrication of cryogels using methacrylated chitosan (Chi-MA) and methacrylated chondroitin sulfate (CS-MA) via radical crosslinking.
• Pulverization of cryogels into microsized CMPs, characterization of physical, mechanical, and biological properties.
• Assessment of V-CMP injectability (shear-thinning), rhVEGF release kinetics, and in vitro endothelial cell proliferation.
• In vivo evaluation in a hindlimb ischemia mouse model to assess neovascularization and tissue survival.

Main Results:

• The developed CMPs exhibited shear-thinning properties, enabling extrusion through a 23G needle.
• V-CMPs demonstrated sustained release of rhVEGF and enhanced in vitro proliferation of endothelial cells.
• In vivo studies showed significant neovascularization and effective prevention of tissue necrosis in the hindlimb ischemia model.

Conclusions:

• The injectable V-CMP system is a promising platform for delivering growth factors for tissue regeneration.
• This technology holds potential for applications requiring enhanced neovascularization and tissue repair, such as in treating ischemic conditions.