Fibroblast apoptosis and caspase-8 activation in aseptic loosening

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Evaluation of Caspase Activation to Assess Innate Immune Cell Death
10:23

Evaluation of Caspase Activation to Assess Innate Immune Cell Death

Published on: January 20, 2023

F Renò1, M Sabbatini, A Massè

  • 1Human Anatomy Laboratory, Research Center for Biocompatibility, Medical Sciences Department, University of Eastern Piedmont "A. Avogadro", Via Solaroli 17, 28100 Novara, Italy.

Biomaterials
|July 2, 2003
PubMed

Insights

Apoptosis is present in aseptic loosened hip implants, particularly in cemented ones. This suggests a potential TNF-alpha-dependent cell death pathway in fibroblast-like cells within these interface membranes.

Area of Science:

  • Orthopedic Surgery
  • Cell Biology
  • Biomaterials Science

Background:

  • Loosened total hip arthroplasty (THA) is a significant clinical challenge.
  • Interface membranes form around loosened THAs, influencing implant survival.
  • Understanding cellular mechanisms like apoptosis in these membranes is crucial.

Purpose of the Study:

  • To investigate the presence and characteristics of apoptosis in interface membranes from loosened THAs.
  • To compare apoptosis levels in aseptic versus septic loosening.
  • To identify cell types involved in apoptosis and potential pathways.

Main Methods:

  • Analysis of interface membranes from revision THA surgery.
  • Terminal deoxyrobonucleotidyl transferase (TdT) assay for DNA fragmentation.
  • Caspase-8 immunostaining to assess apoptosis activation.
  • Morphological identification of positive cells (fibroblast-like and immunocompetent).

Main Results:

  • Significant apoptosis detected in aseptic samples (cementless and cemented), but not in septic samples.
  • Activated caspase-8 was significantly higher in aseptic cemented samples (9.0%) compared to cementless (1.35%).
  • Fibroblast-like cells were the predominant caspase-8 positive population in aseptic cemented membranes (76.6%).

Conclusions:

  • Apoptosis is a key feature of aseptic loosening in THA interface membranes.
  • Caspase-8 activation, particularly in fibroblast-like cells, suggests a potential TNF-alpha-dependent apoptotic pathway.
  • Findings highlight differences between aseptic and septic loosening mechanisms.

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