Skeletal Muscle Spheroids as Building Blocks for Engineered Muscle Tissue

Area of Science:

• Tissue Engineering
• Bioprinting
• Cell Biology

Background:

• Cell spheroids enhance cell-cell interactions and mimic in vivo environments.
• Skeletal muscle spheroids are poorly understood as building blocks for 3D engineered tissues.
• Bioprinting offers a strategy to replicate native tissue organization.

Purpose of the Study:

• To characterize skeletal muscle spheroid formation and viability after bioprinting.
• To investigate the potential of skeletal muscle spheroids in alginate bioink for myogenic tissue bioprinting.
• To compare the myogenic potential of spheroids versus monodisperse cells in 3D constructs.

Main Methods:

• C2C12 mouse myoblasts and primary bovine muscle stem cells (MuSCs) were used to form spheroids.
• Spheroid formation was characterized by duration and cell seeding density.
• Skeletal muscle spheroids were entrapped in alginate bioink and bioprinted; cell viability, fusion, and myogenic differentiation markers were assessed.

Main Results:

• Both C2C12 and bovine MuSC spheroids maintained viability after bioprinting.
• Spheroids fused into larger clusters and formed tissue comparable to monodisperse cells within alginate.
• C2C12 spheroids showed increased MyHC expression, while bovine MuSC spheroids exhibited enhanced cell spreading; both cell types showed increased myogenic differentiation gene expression.

Conclusions:

• Skeletal muscle spheroids can be used as building blocks for 3D bioprinting of myogenic tissue.
• Bioprinted spheroids demonstrate fusion and tissue formation capabilities.
• Skeletal muscle spheroids exhibit potential for enhanced myogenesis and myogenic differentiation in engineered tissues.