Cartilage Damage and Repair

Degeneration of cartilage in the rotator cuff following overuse

Micro computed tomography (µCT) images of the humeral head following rotator cuff tendon overuse (Parks, et al., J Ortho Res 2016: DOI 10.1002/jor23496).

After 10 weeks of rotator cuff overuse, rat humeral articular cartilage displayed loss of matrix integrity
Decreased cartilage thickness, increased dye attenuation,and loss of glycosaminoglycan (GAG) staining can all be seen in the overuse cartilage when compared to the age-matched control tissue
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Supraspinatus tendon overuse

Repair:

GAG microparticles to modulate growth factors in tissue microenvironment

CSMA (chondroitin sulfate) microparticles incorporated into human mesenchymal stem cells (hMSC) aggregates. After 14 days, microparticles remain incorporated in spheroids (left) and aggrecan deposition was observed (right). Scale bar is 50 um (Lei, et al., J Biomed Mater Res A. 2016: DOI 10.1002/jbm.a.35713).

Chondroitin sulfate microparticles were successfully incorporated into human mesenchymal stem cell aggregates
Gene expression of chondrogenic markers occurred earlier with chondroitin sulfate microparticles in aggregates
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Human mesenchymal stem cell aggregates

Surface modification of cells with GAG molecules

Confocal images of Alexafluor 633-tagged heparin
coating at 5 mg/mL coating over 14 days. Scale bar = 100um (Lei, et al., Biomater Sci 2014 1;2(5):666-673).

Degree of attenuation of tumor necrosis factor-alpha (TNF-α) secretion by LPS-activated monocytes (a measure of inflammation) in co-culture with MSCs in monolayer, coated MSC spheroids, or noncoated spheroids. *Statistically different from monolayer, p < 0.05,n = 5 (Lei, et al., Biomater Sci 2014 1;2(5):666-673).

Heparin coating can sequester positively-charged proteins
Heparin coating does not negatively affect cell viability or anti-inflammatory properties of mesenchymal stem cell spheroids/aggregates
Coating technology is a novel platform to present growth factors to cells in aggregates and to surrounding environment
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Characterization of a multilayer heparin coating Human mesenchymal stem cell aggregates Fibroblastic differentiation of human MSCs