Theoretical analysis of complex oscillations in multibranched microvascular networks

Area of Science:

• Physiology
• Biophysics
• Mathematical Biology

Background:

• Microvascular networks exhibit complex diameter oscillations (vasomotion).
• The myogenic response is a key factor in regulating vascular tone.
• Understanding oscillation dynamics is crucial for microcirculation research.

Purpose of the Study:

• To investigate the origin of complex self-sustained diameter oscillations in multibranched microvascular networks using a mathematical model.
• To explore the influence of biomechanical factors and the myogenic response on oscillation patterns.
• To analyze the transition between periodic and chaotic oscillations and their impact on blood flow.

Main Methods:

• Developed a mathematical model of a three-level branching microvascular network based on in vivo hamster dorsal cutaneous muscle data.
• Incorporated radius-dependent elastic and active wall stress and static/dynamic myogenic responses.
• Performed simulations on isolated arterioles and the entire network to analyze diameter oscillations.

Main Results:

• Isolated arterioles showed self-sustained oscillations at constant transmural pressure.
• The network model exhibited diverse oscillatory patterns: periodic, quasiperiodic, and chaotic.
• Chaos was identified by noise-like frequency spectra and sensitivity to perturbations.
• Myogenic response, acting as a nonlinear contracting mechanism, induced varied oscillatory patterns.

Conclusions:

• The myogenic response can induce complex, self-sustained oscillations in microvascular networks.
• Transitions to chaotic oscillations can occur with minor parameter variations (e.g., systemic pressure, arterial resistance).
• Vasomotion patterns, including chaotic ones, influence blood flow distribution within branching vessels.