Engineering a TMJ Disc

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Engineering a TMJ Disc

• Danielle Lewis
• Louisiana Tech University REU, University of
  Louisiana at Lafayette
• Dr. David Mills
• Louisiana Tech University

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What is a TMJ Disc?

• Temporomandibular Joint Disc
• Located between the base of the skull and the
  lower jaw
• Allows for smooth opening and closing of the jaw

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TMDs Temporomandibular Disorders

• Improper disc placement hampers proper jaw
  movement, called disc displacements
• 7-28 of adult population affected, mainly
  females between 18 and 25
• No known treatment for disorder
• In severe cases discs are completely removed and
  patients can no longer move jaw

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http//www.jawjointpainrelief.com/what_is_TMJ.asp
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Current Obstacles in Engineering a TMJ disc

• Recreating the intricate cellular structure
• 3 regions anterior band, intermediate zone, and
  posterior band
• Anterior and posterior bands interlaced collagen
  fiber bundles
• Intermediate zone aligned collagen fibers along
  with tiny fibrochondrocytes and small elastin
  fibers

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Approach of the Mills LabElectrospun Scaffolds

• Electrospinning
• A high voltage is passed through a polymer
  solution inducing an electrostatic repulsion
  force
• The polymer is pumped through an insulin syringe,
  the repulsion force results in the formation of a
  thin jet
• This jet is directed toward a grounded collection
  plate, the solvent evaporates before hitting the
  collection plate and results in the formation of
  a polymer scaffold

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My Research Plan

• Culture bovine fibrochondrocytes (FBCs) in 3
  different gel environments agarose, collagen,
  alginate
• Treat cells with growth factors to observe
  their effect on proliferation, cell survival and
  protein expression
• bFGF
• TGF alpha and beta
• CTGF
• Characterize the extracellular matrix being
  produced by the FBCs

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Cell Isolations

• Bovine FBCs were isolated from TMJ discs taken
  from cow skulls
• Cells used in experiments were passage 6,
  slightly old but still exhibited the
  characteristic FBC shape

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GelsCollagen and Agarose

• FBCs were suspended in both collagen and agarose
  gels and allowed to grow for several days, 18 day
  group and 8 day group

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Fixing, Dehydration, and Paraffin Imbedding

• Gels fixed in 2 paraformaldehyde
• Gels were dehydrated by exposing them to a
  variety of ethanol solutions then infiltrated
  with pariffin to preserve them indefinitely
• Gels were then imbedded in a paraffin block in
  preparation for creating slides
• Next Immunohistochemistry

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Results

• Simple examination under phase contrast showed
  that FBCs thrived better in collagen gels, cells
  attached and displayed characteristic shape

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Is there any explanation for this observation?

• Expected result
• Collagen type I abundant in TMJ disc

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Conclusions

• Bovine fibrochondrocytes appeared to prefer the
  collagen gel environment over the agarose gel
  environment

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Next Steps.

• Begin staining gels for extra-cellular matrix
  proteins
• Hypothesis FBCs grown in collagen gels will
  exhibit an increase in extra-cellular matrix
  proteins over those grown in agarose gels
• Use this experiment as a control and continue by
  adding growth factors to FBCs in gel culture
• Compare the amounts and types of extra-cellular
  matrix proteins found in gels, both with growth
  factors and without, to that found in actual disc
  and FBCs grown on electrospun scaffolds

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Thank you

• Dr. Mills, Kanthi, Skylar, Deepak, Stephanie,
  Paul
• Dr. Jones
• Louisiana Tech for lab facilities in Carson
  Taylor and the BME building
• National Science Foundation