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Expression of TRAIL and death receptor DR4 in Palmer type 2 TFCC lesions
Frank Unglaub1, Susanne B Thomas, Markus W Kroeber
1Department of Plastic and Hand Surgery, University Erlangen, Krankenhausstrasse 12, Erlangen, Germany. Frank.Unglaub@uk-erlangen.de
Introduction:
Degenerative articular disc perforations of the triangular fibrocartilage (TFC) of the wrist are characterized by fibrocartilage cell loss and are often associated with ulna-plus situations. Apoptosis has been found to play a crucial role in fibrocartilage cell loss, however, the molecular mechanism and mediators are still poorly understood.
Aim:
The purpose of this study was to identify receptors to apoptosis in degenerative disc lesions.
Patients:
Included in the study were 17 patients with degenerative articular disc tears of the TFC (Palmer type 2C). Following arthroscopic debridement of the TFC, histological sections were examined to assess the presence of apoptosis. Apoptosis was determined using TRAIL and death receptor DR4 agonists for immunohistochemical analyses. The number of cells positive for apoptosis was then correlated with ulna length.
Results:
Cells positive for TRAIL and DR4 were found in all specimens. The number of cells positive for TRAIL was significantly increased in specimens of patients with an ulna positive variance (P = 0.040). However, DR4 was not significantly increased in ulna plus (P > 0.05). Both, TRAIL and DR4 positive cells were found to be evenly distributed throughout each specimen. There was no accumulation of any type of cells in any particular zone of the biopsies.
Conclusion:
This is the first study that shows that TFCC cells express TRAIL and DR4, which suggests that apoptosis, as well as, mechanical trauma are involved in the development of disc perforation. The TRAIL/DR4 receptor system is a molecular mediator of apoptosis induction in TFC cells and therefore plays a role in cell loss in degenerative disc lesions.
Insights
This study found that TRAIL and DR4 receptors are present in wrist triangular fibrocartilage (TFC) tears, indicating apoptosis contributes to degenerative disc lesions, especially with positive ulnar variance.
Area of Science:
- Orthopedics
- Cell Biology
- Histology
Background:
- Degenerative articular disc perforations of the triangular fibrocartilage (TFC) involve fibrocartilage cell loss, often linked to ulna-plus situations.
- Apoptosis is implicated in this cell loss, but its molecular mediators remain unclear.
Purpose of the Study:
- To identify apoptosis receptors in degenerative TFC disc lesions.
- To investigate the role of TRAIL and DR4 in TFC cell apoptosis.
Main Methods:
- Histological examination of TFC specimens from 17 patients with degenerative tears (Palmer type 2C) after arthroscopic debridement.
- Immunohistochemical analysis using TRAIL and DR4 agonists to detect apoptosis.
- Correlation of apoptosis-positive cell counts with ulna length.
Main Results:
- TRAIL and DR4 positive cells were detected in all TFC specimens.
- A significant increase in TRAIL-positive cells was observed in patients with ulna-plus variance (P=0.040).
- DR4 levels did not significantly correlate with ulna-plus variance, and both receptors were evenly distributed.
Conclusions:
- TFCC cells express TRAIL and DR4, suggesting apoptosis and mechanical trauma contribute to disc perforation.
- The TRAIL/DR4 system acts as a molecular mediator of apoptosis in TFC cells, playing a role in cell loss in degenerative disc lesions.
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