Increased expression of matrix metalloproteinase 1 (MMP1) in 11 patients with patellar tendinosis

Acta Orthop Scand. 2002 Dec;73(6):658-62. doi: 10.1080/000164702321039624.


We studied the expression of procollagen type I, matrix metalloproteinase 1 (MMP1) and tissue inhibitor of metalloproteinase 1 (TIMP-1) by immunohistochemistry in human patellar tendinosis tissues and healthy patellar tendons. In situ gelatin zymography was used to detect collagenolytic activities. The productions of MMP1, TIMP1 and gelatinolytic activities were compared in cell cultures from tendinosis samples and controls. Tendinosis tissues and cultures showed an increase in the expression level of MMP1 and a decrease in that of TIMP1, a condition favoring collagen degradation. Gelatinolytic activities in tendinosis tissues and cultures were elevated. Collagenolysis is a striking feature in patellar tendinosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Collagen Type I / analysis
  • Female
  • Humans
  • Male
  • Matrix Metalloproteinase 1 / analysis*
  • Patella / pathology*
  • Patella / physiopathology
  • Protease Inhibitors / analysis
  • Tendinopathy / pathology*
  • Tendinopathy / physiopathology
  • Tendons / pathology*
  • Tendons / physiopathology
  • Tissue Inhibitor of Metalloproteinase-1 / analysis


  • Collagen Type I
  • Protease Inhibitors
  • Tissue Inhibitor of Metalloproteinase-1
  • Matrix Metalloproteinase 1