Critical transitions in early embryonic aortic arch patterning and hemodynamics

Area of Science:

• Developmental Biology
• Cardiovascular Physiology
• Biomedical Engineering

Background:

• Embryonic aortic arch development involves complex vasculogenic and angiogenic processes.
• Dynamic biomechanical cues, including pulsatile blood flow, influence vascular growth and remodeling.
• Previous studies correlated wall shear stress (WSS) with aortic arch diameter at stages 18 and 24 in chick embryos.

Purpose of the Study:

• Investigate biomechanical events during the critical transition of aortic arch development at stage 21.
• Determine insights into the variable aortic arch patterns observed during this intermediate developmental stage.

Main Methods:

• Utilized fluorescent dye microinjections to identify aortic arch patterns.
• Measured aortic arch diameters using injection recordings and optical coherence tomography.
• Quantified blood flow and WSS via 3D computational fluid dynamics (CFD).

Main Results:

• Aortic arch pattern transition at stage 21 is non-uniform, with multiple configurations observed.
• CFD analysis revealed substantially elevated WSS at stage 21 compared to stages 18 and 24.
• Acute increases in WSS are followed by vascular remodeling to normalize hemodynamic loading.

Conclusions:

• Fluctuations in blood flow may drive variable aortic arch configurations at stage 21.
• Stage 21 represents a temporal window of vulnerability for aberrant aortic arch morphogenesis.
• Understanding these biomechanical events is crucial for comprehending cardiovascular development and potential defects.