Fibronectin production by synovial intimal cells.

Area of Science:

• Rheumatology
• Cell Biology
• Histology

Background:

• Fibronectin distribution in inflamed synovium was previously studied using immunohistochemistry.
• Cytoplasmic staining of intimal cells suggested fibronectin presence.

Purpose of the Study:

• To further investigate fibronectin localization within synovial intimal cells.
• To identify the specific cell type responsible for fibronectin production in synovium.

Main Methods:

• Utilized high-resolution techniques: peroxidase-antiperoxidase staining, light microscopy of semi-thin sections, and immunoelectron microscopy with protein A-gold.
• Examined synovial samples from various joint conditions (osteoarthritis, rheumatoid arthritis, other joint diseases).

Main Results:

• Fibronectin was detected in individual synovial intimal cells in 22 out of 32 samples via light microscopy.
• Electron microscopy identified these positive cells as type B synoviocytes.
• Immunoelectron microscopy confirmed fibronectin presence within the rough endoplasmic reticulum of type B synoviocytes in most samples.

Conclusions:

• Type B synoviocytes are the primary source of fibronectin production in the synovial lining.
• This study elucidates the cellular basis of fibronectin accumulation in inflamed joints.