Granular Hydrogels Improve Myogenic Invasion and Repair after Volumetric Muscle Loss

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Skeletal Muscle Biology

Background:

• Volumetric muscle loss (VML) causes significant scarring and functional loss.
• Current treatments for VML are ineffective.
• Biomaterials are a promising strategy but often lack necessary porosity for cell infiltration.

Purpose of the Study:

• To investigate the impact of granular hydrogels on muscle repair after VML.
• To determine if granular hydrogels can conformably fill defects and support cell invasion.
• To assess the potential of granular hydrogels as a therapeutic for VML.

Main Methods:

• Preparation of small and large microparticle fragments from photocurable hyaluronic acid.
• Assembly of granular hydrogels and analysis of particle size and packing effects on pore features, rheology, and injectability.
• Evaluation of granular hydrogels in a mouse model of VML.

Main Results:

• Granular hydrogels exhibit tunable pore features, rheology, and injectability based on particle size and packing.
• Unlike bulk hydrogels, granular hydrogels facilitate satellite cell invasion (early-stage repair).
• Granular hydrogels promote myofiber regeneration (late-stage repair) in a VML mouse model.

Conclusions:

• Injectable and porous granular hydrogels effectively support endogenous muscle repair processes.
• Granular hydrogels demonstrate significant potential for treating severe muscle injuries like VML.
• This study highlights a novel biomaterial approach for enhancing skeletal muscle regeneration.