Osteoarthritic cartilage fibrillation is associated with a decrease in chondrocyte adhesion to fibronectin.

Area of Science:

• Biomedical Science
• Orthopedics
• Cell Biology

Background:

• Osteoarthritis (OA) is characterized by cartilage destruction, often viewed as a failed tissue repair process.
• Cell adhesion to the extracellular matrix is crucial for tissue repair mechanisms.
• Understanding chondrocyte adhesion in OA is key to exploring potential therapeutic interventions.

Purpose of the Study:

• To investigate the adhesion of chondrocytes from human OA cartilage to extracellular matrix proteins.
• To compare chondrocyte adhesion from intact versus fibrillated cartilage surfaces.
• To examine the effects of protein kinase C (PKC) inhibitors and glucosamine sulfate (GS) on chondrocyte adhesion.

Main Methods:

• Chondrocytes were isolated from human OA femoral head cartilage with intact or fibrillated surfaces.
• Cell adhesion assays were performed using fibronectin and type II collagen as substrates.
• The impact of PKC inhibitors (W7, sphingosine) and glucosamine sulfate (GS) on cell adhesion was evaluated.

Main Results:

• Chondrocytes from fibrillated OA cartilage exhibited significantly decreased adhesion to fibronectin compared to those from intact cartilage.
• Adhesion to type II collagen was not significantly different between cells from intact and fibrillated cartilage.
• PKC inhibitors reduced fibronectin adhesion in cells from intact cartilage, while GS treatment increased fibronectin adhesion in cells from fibrillated cartilage.

Conclusions:

• Fibrillation of OA cartilage is associated with impaired chondrocyte adhesion to fibronectin.
• This defective adhesion appears to involve protein kinase C (PKC) and/or calmodulin-dependent kinases.
• Glucosamine sulfate treatment may offer a potential therapeutic strategy by restoring chondrocyte adhesion in OA.