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Expression of ICAM-1 on isolated human nasal, auricular and costal chondrocytes
1Department of Otorhinolaryngology, Ludwig-Maximilians-University, Munich, Germany.
Insights
Intercellular adhesion molecule-1 (ICAM-1) is not found on healthy cartilage but is expressed by chondrocytes when the extracellular matrix is damaged. This suggests ICAM-1 may contribute to cartilage graft resorption.
Area of Science:
- Immunology
- Cell Biology
- Biomedical Engineering
Background:
- Intercellular adhesion molecule-1 (ICAM-1) is crucial for leukocyte interactions.
- Chondrocytes can express immune-related molecules, and cartilage grafts often show leukocyte infiltration.
- Understanding ICAM-1 in cartilage is important for graft survival in ENT procedures.
Purpose of the Study:
- To investigate the presence and expression of ICAM-1 on human nasal, auricular, and costal cartilage.
- To determine if chondrocytes express ICAM-1 independently of surrounding cells.
- To explore the potential role of ICAM-1 in cartilage graft resorption.
Main Methods:
- Immunohistochemical staining (APAAP) on cartilage tissue sections.
- Flow cytometry analysis of isolated chondrocytes (in suspension and cultured).
- Utilized specific monoclonal antibodies (mAb) for ICAM-1 detection.
Main Results:
- ICAM-1 was not detected on healthy cartilage tissue sections.
- Chondrocytes isolated from the matrix and cultured chondrocytes exhibited strong positive staining for ICAM-1.
- This expression was consistent across nasal, auricular, and costal cartilage samples.
Conclusions:
- Chondrocytes can synthesize ICAM-1 without external stimuli when their extracellular matrix is compromised.
- ICAM-1 expression on chondrocytes may be triggered by tissue damage.
- This finding suggests ICAM-1 is a potential factor in the destructive resorption of cartilage grafts.
Abstract:
Expression of intercellular adhesion molecule-1 (ICAM-1) on targets has been reported to be a relevant factor for leukocyte migration, adhesion and function. Because stimulated chondrocytes have been shown to express molecules of immunological import (like HLA class II antigens) and because rejected or resorbed cartilage grafts used in the field of ENT are often characterized by adjacent infiltrating leukocytes, the presence of ICAM-1 on human nasal, auricular and costal cartilage was investigated. For this study, cartilage tissue sections and chondrocytes in suspension as well as cultured chondrocytes were prepared. Specific monoclonal antibodies (mAb) were used for immunocyto- and immunohistochemical Alkaline-Phosphatase-anti-Alkaline-Phosphatase staining (APAAP staining) as well as for flow cytometry analysis. ICAM-1 on healthy cartilage tissue sections was not found. On the other hand, both chondrocytes freed from matrix and cultured chondrocytes showed strongly positive staining patterns for ICAM-1. This result was obtained for chondrocytes from nasal, auricular as well as costal cartilage. This observed expression of ICAM-1 on chondrocytes with defective extracellular matrix demonstrates that cartilage cells are able to synthesize ICAM-1 without any paracrine stimulus from non-chondrocyte cells. It suggests that ICAM-1 plays a role in processes where tissue damage leads to the exposure of chondrocyte surfaces. Therefore, ICAM-1 expression on chondrocytes may also be a factor in destructive cartilage graft resorption.