Stem cell factor receptor KIT (CD117) in aseptic hip prosthesis loosening

Area of Science:

• Biomaterials Science
• Immunology
• Orthopedic Surgery

Background:

• Aseptic hip prosthesis loosening (AHPL) is a significant complication of total hip replacement.
• Understanding the inflammatory mechanisms underlying AHPL is crucial for developing effective treatments.
• Mast cells and their receptors are implicated in inflammatory processes.

Purpose of the Study:

• To investigate the expression and localization of stem cell factor receptor KIT (CD117) in AHPL tissue.
• To determine the colocalization of CD117 with mast cell tryptase (MCT), a specific mast cell marker.
• To explore the potential role of CD117-expressing cells in AHPL pathogenesis.

Main Methods:

• Immunohistochemical analysis of CD117 in tissue from 10 AHPL patients and 4 controls.
• Serial section analysis and double staining to assess CD117 and MCT colocalization.
• Semi-quantitative analysis of CD117 and MCT expression.
• Double labeling for CD117/MCT and polyethylene (PE) particles.

Main Results:

• CD117 was predominantly found in MCT-positive mast cells in AHPL tissues, with high correlation (r=0.86, p<0.01).
• CD117/MCT-positive cells were located in perivascular areas and near macrophages/multinucleated giant cells.
• Polyethylene particles were not detected within CD117/MCT-positive mast cells.
• CD117/MCT-positive cells were less frequent in control samples.

Conclusions:

• This study is the first to report CD117 expression in AHPL, identifying it mainly in a distinct mast cell subgroup.
• CD117, as a growth factor receptor, may play a significant role in mast cell recruitment and activation in AHPL.
• Mast cells do not appear to phagocytose significant amounts of polyethylene particles, but their influence on this process requires further investigation.