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Molecular and Rheological Characterization of Hyaluronic Acid and Equine Synovial Fluid for the Treatment of Lameness in PowerPoint Presentation
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Molecular and Rheological Characterization of Hyaluronic Acid and Equine Synovial Fluid for the Treatment of Lameness in Horses. Sara Tracy Advisors: Dr. Skip Rochefort PhD and *Dr. Jill Parker DVM Danielle Leiske Dept. of Chemical Engineering and *College of Veterinary Medicine

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Molecular and Rheological Characterization of Hyaluronic Acid and Equine Synovial Fluid for the Treatment of Lameness in Horses

Sara Tracy

Advisors:Dr. Skip Rochefort PhD and *Dr. Jill Parker DVM

Danielle Leiske

Dept. of Chemical Engineering and *College of Veterinary Medicine

Oregon State University

Corvallis, Oregon

objective
Objective
  • Establish normal properties of equine synovial fluid
  • Compare to properties of hyaluronic acid solutions of various concentrations
motivation
Motivation
  • The horse industry loses around 1 billion dollars annually due to lameness.
  • Lameness: An indication of a structural or functional disorder in one or more limbs that is evident during movement or in the standing position.
  • Hyaluronic acid is used to treat joint problems in both horses and humans.
background
Background

Synovial Fluid

  • Multipurpose fluid surrounding all articular joints
  • Synovial fluid has both viscous and elastic properties (viscoelastic)
    • Viscosity relates to lubrication
    • Elasticity relates to shock absorption
background5
Background

Hyaluronic Acid (HA)

  • High molecular weight biopolyelectrolyte made up of repeating glucuronic acid and N-acetylglucosamine subunits
  • Major component of synovial fluid
  • Exhibits viscoelastic properties
  • Commonly obtained from:
    • Chicken combs
    • Human umbilical cords
    • Bacterial fermentation processes
  • Molecular weight around
    • 0.5 to 10 million Da
joints
Joints
  • Joints of focus
joints7
Joints
  • Skeletal view of the joints
joints8
Joints
  • Common problems with equine joints:
    • Degenerative Joint Disease – DJD
      • Damage to the articular cartilage
      • Commonly affects heavily worked and aged horses
    • Osteochondritis Dissecans – OCD
      • Failure of the bone underlying the smooth articular cartilage to form properly
      • Commonly affects young horses
joints9
Synovial Fluid

Average HA concentration

0.5 to 5.0 mg/mL

Average molecular weight

2 to 10 million Da

Viscosity at a shear rate of 0.1/second

0.1 to 1.0 Poise

Hyaluronic Acid Joint Supplementation

Intra-articular injection

Intravenous injection

Oral administration

Synthovial 7/Hyalun

Molecular weight - around 1.5 million Da

Concentration – 3 to 5 mg/mL

Joints
tests
Tests

Rheology

  • The rheometer measures both

ELASTICITY and VISCOSITY

    • Steady shear test measures the viscosity as a function of shear rate
    • Dynamic oscillatory shear test measures the viscous modulus and elastic modulus as a function of frequency

Rheometrics RFS II

tests11
Tests

Steady Shear Test

  • Plate rotates at increasing shear rates
  • Torque, or shear stress, is measured by the rheometer
    • Viscosity =

shear stress

shearrate

tests12
Tests
  • Bottom plate rotates at increasing shear rates
  • Shear stress is measured on the top cone
  • Viscosity decreases with increasing shear rates due to molecular disentanglement
tests16
Tests

Dynamic Oscillatory Shear Test

  • Plate oscillates at increasing frequencies
  • Strain and stress are measured to determine G’ and G’’
    • G’ represents the elastic (storage) modulus
    • G’’ represents the viscous (loss) modulus
  • When G’ > G’’ the fluid behaves more elastic
  • When G’ < G’’ the fluid behaves more viscous
tests17
strain = imposed

stress = measured

G’ (elastic modulus) = in phase

G’’ (viscous modulus) = out of phase

Tests
tests21
Tests

Capillary Viscometry

  • Known dilutions of the fluid are used and the flow times are measured
  • The flow times are used to measure relative viscosity
    • Relative viscosity =

solution flow time

solvent flow time

conclusion
Conclusion
  • Different joints have different rheological properties, which could mean different HA concentrations
  • Synovial fluid obtained from the hock joint behaves like a 1 to 2 mg/mL HA solution, and stifle joint fluid behaves like a 2 to 3 mg/mL HA solution
future work
Future Work
  • Perform light scattering to determine the specific concentration and molecular weight of HA in synovial fluid samples
  • Study the effectiveness of different forms of administering HA
  • Explore the effects of varying molecular weights and concentrations of HA supplements on an equine test group
acknowledgements
Howard Hughes Medical Institute

URISC

Dr. Skip Rochefort, OSU ChE Dept

Dr. Jill Parker, OSU College of Veterinary Medicine

Danielle Leiske and Erica Zaworski

Dr. Kevin Ahern

Acknowledgements