Cumulative Effects of Hypercholesterolemia on Tendon Biomechanics in a Mouse Model

High cholesterol represents a significant healthcare problem. Clinical studies have linked hypercholesterolemia to Achilles tendon xanthomas and rotator cuff tears, and research in other systems indicates detrimental effects of high cholesterol; however, understanding of its impact on tendon properties and healing is limited. We hypothesized that tendons from aging hypercholesterolemic (APOE) mice would exhibit inferior baseline and healing mechanical properties compared to controls, while younger, but mature mice would be no different. Surprisingly, tensile testing of patellar tendons from 14-week-old APOE mice receiving a unilateral full-thickness central defect resulted in normalized (injured:sham) cross-sectional areas closer to baseline (p = 0.02) compared to controls. Uninjured data from 10-month-old APOE mice showed a decrease in elastic modulus (p = 0.02), indicating a detrimental effect of hypercholesterolemia on tendon properties in this model. These results could benefit patients through knowledge that high cholesterol could increase the likelihood of tendon tears. Furthermore, knowledge that tendon tears are indicative of high cholesterol could provide orthopedic clinicians with an additional preventive treatment opportunity for patients with undiagnosed hypercholesterolemia. (C) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:380-383, 2011