Main roles of some matrix metalloproteases (MMPs) and tissue inhibitors of metalloproteases (TIMPs)
| MMP1 | • Upregulated in acute tendon tears3 |
| • Upregulated in tendinopathy14 | |
| • Upregulated in response to shear stress15 | |
| • Downregulated in response to cyclical strain and static tensile load16,17 | |
| MMP2 | • Upregulated in tendinopathy8 |
| • May be upregulated13 or downregulated3 in complete tendon tears | |
| • Inhibits TIMP1 and TIMP2 in response to exercise10 | |
| MMP3 | • Plays a major role in maintenance and remodelling of normal tendon3,7 |
| • Downregulated in tendinopathy and complete tendon tears3,6,8,12 | |
| • Upregulated in response to shear force8 | |
| MMP13 | Upregulated in complete tendon tears12 |
| MMP9 | Upregulated following exercise9,10 |
| TIMP1 | • Downregulated in tendinopathy7,14 |
| • Upregulated transiently following an acute tendon tear13 | |
| • Inhibits excessive degeneration of ECM by MMP213 | |
| TIMP2, TIMP3, TIMP4 | Downregulated in tendinopathy7 and complete tendon tears12 |