Non-Invasive Optical Motion Tracking Allows Monitoring of Respiratory Dynamics in Dystrophin-Deficient Mice

Area of Science:

• Biomedical Engineering
• Respiratory Physiology
• Translational Research

Background:

• Duchenne muscular dystrophy (DMD) causes progressive muscle weakness and cardiorespiratory failure.
• Preclinical assessment of diaphragm function in DMD models is limited.
• A reliable, translatable method to track disease severity is needed.

Purpose of the Study:

• To develop a sensitive, reliable, and harmless method for assessing respiratory muscle weakness in DMD.
• To establish Optical Respiratory Dynamics Tracking (ORDT) for monitoring breathing pattern irregularities.

Main Methods:

• Developed ORDT using a camera to track thoracic-abdominal movement with paper markers.
• Compared ORDT measurements with established X-ray based lung function (XLF).
• Validated ORDT using smartphone acquisition for simplicity and reliability.

Main Results:

• ORDT distinguished between mdx (DMD model) and wildtype mice by detecting higher expiration constants (k) in mdx mice.
• ORDT identified distinct fast and slow expiratory phases, with mdx mice showing greater displacement in the fast phase.
• Results were comparable to XLF, but ORDT provided additional phase-specific data.

Conclusions:

• ORDT is a sensitive, reliable, and easy-to-use preclinical tool for monitoring respiratory changes in DMD.
• The method has potential for tracking disease progression and therapy response in neuromuscular disorders.
• Smartphone adaptability enhances its translatability and accessibility for research.