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Polymorphonuclear granulocytes in rheumatic tissue destruction. II. Demonstration of PMNs in rheumatoid nodules by
Abstract:
Necrotic areas of rheumatoid nodules were investigated electron microscopically. PMNs in different stages of disintegration were present in all cases. Granular material, sometimes in a fiberlike orientation, and small fibrils without periodicity were detected between the collagenous fibers. It is assumed that granular material and fibrillar remnants represent degraded collagen. Often these degradation products were present in the neighborhood of disintegrating PMNs. From this morphological relationship it is concluded that enzymes of PMNs may in part be responsible for the fibrinoid necrosis in rheumatoid nodules.
Insights
Electron microscopy revealed that enzymes from polymorphonuclear neutrophils (PMNs) may contribute to fibrinoid necrosis in rheumatoid nodules by degrading collagen. This finding offers insight into the tissue damage mechanisms in rheumatoid arthritis.
Area of Science:
- Rheumatology
- Pathology
- Cell Biology
Background:
- Rheumatoid nodules are characteristic lesions in rheumatoid arthritis.
- The pathogenesis of fibrinoid necrosis within these nodules is not fully understood.
Purpose of the Study:
- To investigate the ultrastructural changes in necrotic areas of rheumatoid nodules.
- To identify the cellular and extracellular components involved in fibrinoid necrosis.
Main Methods:
- Electron microscopy was used to examine tissue samples from rheumatoid nodules.
- Morphological analysis focused on polymorphonuclear neutrophils (PMNs) and extracellular matrix components.
Main Results:
- Polymorphonuclear neutrophils (PMNs) in various stages of disintegration were consistently observed.
- Degraded collagen, appearing as granular and fibrillar material, was detected.
- These collagen degradation products were frequently found near disintegrating PMNs.
Conclusions:
- The morphological association suggests that enzymes released from PMNs play a role in the collagen degradation observed.
- PMN-derived enzymes are implicated as a contributing factor to fibrinoid necrosis in rheumatoid nodules.