Endothelial Network Formation Within Human Tissue-Engineered Skeletal Muscle.

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Cell Biology

Background:

• Skeletal muscle tissue engineering is limited by the absence of vascular networks in vitro.
• Bioartificial muscle (BAM) models offer a promising approach for skeletal muscle regeneration.
• Integrating vascular networks is crucial for the development of larger engineered muscle constructs.

Purpose of the Study:

• To optimize co-culture conditions for human muscle progenitor cells and human umbilical vein endothelial cells (HUVECs) within a fibrin extracellular matrix (ECM).
• To develop a vascularized bioartificial muscle (BAM) model for enhanced skeletal muscle tissue engineering.
• To determine the optimal cell density and cell ratios for myofiber alignment and endothelial network formation.

Main Methods:

• Co-culturing muscle progenitor cells and HUVECs in a fibrin ECM under tension.
• Evaluating different culture medium conditions using a fusion assay.
• Testing various total cell numbers and myoblast-HUVEC ratios.
• Assessing the impact of Matrigel addition on tissue formation.

Main Results:

• Endothelial growth medium was identified as optimal for co-culture without compromising myoblast fusion.
• A total cell density of 2 × 10^6 cells, with 50% HUVECs, promoted well-aligned myofibers and interspersed endothelial networks.
• Higher myoblast numbers improved network formation up to a plateau at 1 × 10^6 myoblasts.
• Matrigel addition did not significantly enhance myofiber or endothelial network development.

Conclusions:

• The optimized BAM model utilizes a fibrin ECM with 2 × 10^6 cells (50-70% muscle cells).
• These findings provide a foundation for engineering larger, physiologically relevant in vitro muscle constructs.
• The developed co-culture strategy facilitates the integration of vascular networks within engineered skeletal muscle.