Reduction of water diffusion coefficient with increased engineered cartilage matrix growth observed using MRI

Area of Science:

• Biomedical Engineering
• Biomaterials Science
• Medical Imaging

Background:

• Non-destructive monitoring of engineered cartilage is crucial for optimizing growth.
• Quantitative biomarkers for extracellular matrix (ECM) development are needed.
• Magnetic Resonance Imaging (MRI) offers non-invasive 3D tissue mapping using water relaxation times and apparent diffusion coefficient (ADC).

Purpose of the Study:

• To investigate the potential of apparent diffusion coefficient (ADC) as a non-destructive biomarker for engineered cartilage growth.
• To assess the impact of chondrocyte seeding density and ascorbic acid on ADC values.
• To correlate ADC changes with extracellular matrix development over a one-month incubation period.

Main Methods:

• Bovine chondrocytes were seeded in alginate beads at varying densities (0-4 million cells/ml).
• Diffusion-weighted MRI at 14.1 T was used to measure ADC weekly over one month.
• Two groups were compared: with and without ascorbic acid supplementation.

Main Results:

• Normalized ADC monotonically decreased with incubation time, showing up to a 40% reduction at 4 weeks.
• Ascorbic acid administration led to a further decrease in normalized ADC.
• These ADC changes correlated with expected extracellular matrix development.

Conclusions:

• Normalized ADC is a promising non-destructive biomarker for characterizing engineered cartilage tissue growth.
• ADC measurements can provide insights into ECM development and the effects of supplements like vitamin C.
• This technique aids in optimizing conditions for tissue-engineered cartilage development.