Evaluation of engineered meniscal cartilage constructs based on different scaffold geometries using magnetic resonance imaging and spectroscopy.
Magnetic resonance imaging (MRI) and spectroscopy (MRS) were used to evaluate the properties different scaffold geometries for the production of bioartificial meniscal cartilage constructs. Engineered were generated in perfusion bioreactors from mature sheep meniscal fibrochondrocytes,scaffolds cut from a knitted polyethylene therephtalate (PET) fabric, with a distribution of fibers, 50 microm pores and a density of 45 mg/cm(3) (NF scaffolds), and from two versions of this fabric, which included larger pore sizes (1500 x 500 microm(2)) and densities of (sIV scaffolds) and 83 mg/cm(3) (sV scaffolds). MRI methods were used to determine the permeability the constructs to a low molecular weight MR contrast agent and to measure the macroscopic of medium through and around the constructs. These parameters were correlated with measurements of cell growth and cellular energetics. Cell-free sIV scaffolds were 2- and 5-more porous to flow than the empty sV and NF scaffolds, respectively. These scaffolds, after days of cell growth, were also more permeable to an MR contrast agent. sIV scaffolds yielded(n = 9) with higher cellularities (41 +/- 1%) compared with NF (32 +/- 1%, p < 0.0001) and sV (30 +/- 1%, p < 0.0001) and, when normalized to cell numbers, demonstrated proportionally levels of nucleoside triphosphates (NTP), indicating increased cell viability. Scaffold geometry a marked effect on the properties of engineered meniscal cartilage. MRI and MRS are powerful techniques that can be used to optimize the design of engineered meniscal cartilage and that could be used subsequently to evaluate clinical outcome postimplantation.