Distribution of fibronectins and their integrin receptors in interface tissue from aseptic loosening of hip prostheses

Objectives To assess the distribution of fibronectins (FNs) and their integrin (Int) r eceptors in synovial membrane-like interface tissue (SMLIT) from aseptic lo osening of total hip replacement (THR), and potential role of FN-Int intera ction in the loosening process. Methods The alkaline phosphatase anti-alkaline phosphatase (APAAP) method was used to detect the distribution of FNs and their Int receptors in SMLIT and cont rol samples. Double immunofluorescence labeling was used to reveal the diff erent co-localizations. Results Intensive FN staining appeared in the lining layers, sublining area, and va scular endothelium, while immunoreactivities for Int alpha 4, alpha 5, beta 1 subunits were detected in the lining and endothelial cells of SMLIT Immu nofluorescence labeling revealed Int a5 and collagenase-1/collagenase-3 dou ble positive cells in lining layers and sublining area of SMLIT. Conclusion Increased expression of FNs, Int alpha 4 beta 1 and alpha 5 beta 1 appeared in SMLIT compared with that in OA synovial membrane. FN-Int interactions m ay play a role in local collagenase production.