title: Hypercholesterolemia increases supraspinatus tendon stiffness and elastic modulus across multiple species.
abstract: BACKGROUND
  More than one-quarter of Americans have hypercholesterolemia and/or are being treated with cholesterol-lowering medications. Given the systemic nature of hypercholesterolemia and remaining questions regarding its effect on tendons at a local level, we sought to assess the utility of small versus large animal model systems for translational studies by exploring the effect of hypercholesterolemia on supraspinatus tendon elastic mechanical properties in mice, rats, and monkeys. We hypothesized that stiffness and elastic modulus would be increased in tendons across species due to hypercholesterolemia.
  
  
  METHODS
  Supraspinatus tendons from normal (control) and high-cholesterol (HC) mice, rats, and monkeys were used in this study. After dissection, tendons were geometrically measured and tensile tested with tissue strain measured optically.
  
  
  RESULTS
  Overall, HC animals had significantly altered plasma lipid profiles. Biomechanical testing showed a significant increase in stiffness compared with control in HC mice and rats, as well as a nonsignificant trend for HC monkeys. Elastic modulus was also significantly increased in HC mice and monkeys, with HC rats showing a trend.
  
  
  CONCLUSIONS
  The consistency of our findings across species and between small and large animals, combined with the fact that the aged mice were exposed to lifelong hypercholesterolemia (compared with rats and nonhuman primates, which were fed HC diets), suggests that these increased properties may be inherent to the effect of hypercholesterolemia on supraspinatus tendon rather than due to an effect of cumulative exposure time to the effects of HC. Further investigation is needed to confirm this concept.
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Beason
authors.forename: Jason E
authors.initials: JE
authors.lastname: Hsu
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Marshall
authors.forename: Allison L
authors.initials: AL
authors.lastname: McDaniel
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Temel
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Abboud
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002522:Chlorocebus aethiops; D004195:Disease Models, Animal; D055119:Elastic Modulus / Q000502:physiology*; D006937:Hypercholesterolemia / Q000150:complications / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D051381:Rats; D017207:Rats, Sprague-Dawley; D013710:Tendons / Q000503:physiopathology*