IADR Abstract Archives

Temporomandibular Joint Articular Disc: Origin and Regeneration

Objectives: Temporomandibular joint (TMJ) disorders impact between 5%-15% of US citizens. There are limited treatment options for damaged or degenerated articular discs (AD) of the TMJ. The AD is classically described as fibrocartilage with lateral pterygoid (LP) tendon ‘attachments’. However, a long-forgotten description postulated the LP tendon becomes pinched between the mandibular condyle and articular eminence resulting in the articular disc structure. Since understanding the origin and composition of this tissue is essential for developing regenerative strategies for AD pathologies, we used modern molecular tools to reexamine this old hypothesis. Our aim is to utilize the knowledge gained to guide in vitro tissue regeneration of the AD, potentially using progenitor cells derived from the AD.

Methods: TMJs of ScleraxisGFP (Scx) tendon reporter and ScxnullGFP mice, Pax7RFP (muscle) and Gdf5RFP (joint) mice were studied to delineate TMJ tissues. In parallel, we examined the molecular profile of Rhesus macaque ADs and isolated novel progenitor cell clones from them by differential plate adhesion.

Results: ScxGFP and Pax7RFP reporters indicate Scx is expressed continuously from the myotendinous junction of the LP through the AD and posterior attachments. Gdf5RFP localizes near the posterior region of ScxGFP expression. ScxnullGFP mice have poor matrix formation especially in the anterior region of the AD. Furthermore, we found common tendon markers in R.macaque disc, with minimally expressed chondrogenic markers, and isolated progenitor cells from R.macaque discs that undergo trilineage differentiation and produce fibrocartilage in vitro.
Conclusions: Our results indicate the AD is a continuous structure originating from the LP tendon. Tendon biomarkers were identified in the AD of two species commonly utilized as TMJ model organisms. Furthermore, it is possible to isolate clonable, expandable cells that continue exhibiting tendon/fibrocartilage features in vitro. A tendon origin for the disc suggests novel sources of grafts for its replacement, and presents new targets for tissue engineering.
AADR/CADR Annual Meeting
2018 AADR/CADR Annual Meeting (Fort Lauderdale, Florida)
Fort Lauderdale, Florida
2018
0042
Craniofacial Biology Research
  • Weekes, Kenneth  ( Oregon Health and Science University , Milwaukee , Oregon , United States ;  Oregon Health & Science University , Portland , Oregon , United States )
  • Pal, Deepanwita  ( Shriners Hospitals for Children , Portland , Oregon , United States )
  • Pryce, Brian  ( Shriners Hospitals for Children , Portland , Oregon , United States )
  • Lam, Phillip  ( Oregon Health & Science University , Portland , Oregon , United States )
  • Schweitzer, Ronen  ( Shriners Hospitals for Children , Portland , Oregon , United States )
  • Johnstone, Brian  ( Oregon Health & Science University , Portland , Oregon , United States ;  Shriners Hospitals for Children , Portland , Oregon , United States )
  • NONE
    Oral Session
    Temporomandibular Joint and Mandibular Condylar Cartilage
    Wednesday, 03/21/2018 , 01:30PM - 03:00PM