Six-Axis, Physiological Activity Profiles Create a More Challenging Cellular Environment in the Intervertebral Disc...

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Biomechanics

Background:

• Bioreactors are crucial for studying intervertebral disc (IVD) mechanics and biology.
• Replicating real-world loading conditions in bioreactors remains a significant challenge for IVD research.

Purpose of the Study:

• To develop population-based activity profiles using in vivo data for realistic IVD bioreactor loading.
• To investigate the impact of six-axis loading on IVD cell viability.

Main Methods:

• Combined time use surveys and six-axis in vivo load data to create activity profiles.
• Utilized a novel six-axis bioreactor with whole-organ bovine tail IVD models.
• Compared cell viability under six-axis loading versus single-axis or unloaded conditions.

Main Results:

• Six-axis loading created a more demanding environment than single-axis or no loading.
• Cell viability was reduced in both nucleus pulposus and annulus fibrosus under six-axis loading.
• A more active lifestyle profile further decreased annulus fibrosus cell viability due to increased strains.

Conclusions:

• Six-axis loading in bioreactors provides a more ecologically valid model for IVD research.
• Realistic simulation of daily activities is essential for evaluating IVD therapies.
• Findings emphasize the need to consider diverse activity levels for successful clinical translation of IVD interventions.