Tendon Damage and Repair

Histology of rat tendons(A & B), normal tendon, arrows indicate normal tendon cells with a spindle-like morphology; (C & D), overused tendon, arrows indicate rounded tendon cells. Scale bar = 25 μm.

Higher Cathepsin L staining (red) at the insertion was found in the overuse group vs. control at 4 weeks. Scale bar =  100. μm (Seto, et al., Ann Biomed Eng. 2015 DOI 10.1007/s10439-014-1245-8).

Cathepsins L (B) and K (C) activity at the insertion region after 4 weeks of overuse compared to age-matched controls. * indicates significantly greater activity over controls at the same timepoint (p<0.05) (Seto, et al., Ann Biomed Eng. 2015 DOI 10.1007/s10439-014-1245-8).

• Chronic tendinopathy is caused by repeated injury and can result in pain and decreased mechanical properties.
• A class of cysteine proteases, cathepsins, contain the most potent human collagenases, and therefore may play a role in matrix damage during tendon overuse
• Cathepsins L & K activity was significantly higher at the insertion region of the overused tendon, rather than the midsubstance, suggesting localized damage
• Click link below to read more from this paper on PubMed:
  

  Cathepsins in Rotator Cuff Tendinopathy

• Cells delivered in a degradable hydrogel can migrate into a ex-vivo model tendon defect
• Greater number of delivered cells were observed in the tendon defect using degradable hydrogels than nondegradable
• Click link below to read more from this paper on PubMed:

PEG-based hydrogels