Emerging Ideas: The Effect of Hypercholesterolemia on Tendons

High levels of total cholesterol, triglycerides, and low-density lipoprotein are toxic to the vascular endothelium and thus have long been associated with atherosclerosis. Several clinical studies have suggested that elevated cholesterol also has a negative effect on tendon structure and function. Data from our preliminary studies show that the patellar tendons of hypercholesterolemic knockout mice exhibit reduced baseline elastic modulus and strength postinjury compared with controls. We therefore hypothesized elevated cholesterol would be associated with diminished tendon mechanical properties. Using hypercholesterolemic (B6.129P2-Apoetm1Unc/J) mice, patellar tendons from control (C57BL/6) and knockout mice will be injured surgically at two different times. Subsequently, mechanical testing will be performed and data evaluated for differences in baseline and in healing between cholesterol groups. For healing assessment, data from the injured limb of each animal will be normalized to that of the sham-operated contralateral limb. We anticipate that such studies eventually will enable us to elucidate the link between elevated cholesterol and tendon disease. If a mechanistic cause of hypercholesterolemia causing tendon disease is clarified, then potentially therapeutic interventions such as the use of pharmacotherapy may be used to help combat this. In the future, it may become worthwhile to consider the presentation of tendinopathy as a trigger to measure serum cholesterol just as one might consider measuring serum glucose in patients presenting with adhesive capsulitis.