Multi-scale undulations in human aortic endothelial cell fibers

Area of Science:

• Biomedical Engineering
• Developmental Biology
• Cellular Mechanics

Background:

• Vascular diseases exhibit abnormal blood vessel shapes like kinking and coiling.
• These morphologies are often linked to blood pressure, flow, and cell changes, but originate during development.
• Early vascular development involves angioblasts forming vessel-like fibers before blood flow.

Purpose of the Study:

• Investigate mechanical instabilities in endothelial cell fibers during early vasculogenesis.
• Explore how cellular contractions and matrix interactions influence primitive vessel morphology.
• Develop simple in vitro models to understand the physical causes of undulatory vascular patterns.

Main Methods:

• Cultured endothelial cells within a collagen matrix to form vessel-like fibers.
• Observed and analyzed the morphology and mechanical behavior of these cellular structures.
• Applied mechanical models to interpret the observed undulations and instabilities.

Main Results:

• Endothelial cell fibers demonstrated radial contraction over time.
• Two dominant wavelengths of undulation were observed: approximately 1 cm and 1 mm.
• Mechanical modeling suggested Euler buckling for long wavelengths and energy mismatch for short wavelengths.

Conclusions:

• Cytoskeletal contractions and extracellular matrix elasticity contribute to undulatory vascular morphology.
• Vascular morphology can arise from mechanical instabilities in cellular fibers independent of lumen formation or blood pressure.
• In vitro models provide insights into the fundamental physical principles governing blood vessel development.