MESSENGER-RNA EXPRESSION OF MATRIX METALLOPROTEINASES AND TISSUE INHIBITORS OF METALLOPROTEINASE IN INTERFACE TISSUE AROUND IMPLANTS IN LOOSENING TOTAL HIP-ARTHROPLASTY

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloprote inase (TIMPs) play an important role in tissue destruction and remodel ing. Nine samples of cement interface tissues from nine patients who h ad failed cemented total hip arthroplasty (THA) were obtained for revi sion of THA and analyzed on mRNA expression of MMPs and TIMPs. The pre operative serial radiographic examinations revealed an apparent clear zone around all implants. We excluded septic loosening as one of the f actors affecting THA. Three samples were obtained from three different sites of the ace-tabular interface tissue in each patient. After extr action of total RNA from 27 samples, we used the reverse-transcription al polymerase chain reaction (RT-PCR), mRNA of MMP-1, -2, -3, -9, and TIMP-1 and -2 was detected in the interface tissue. MMP-10 mRNA was no t detected, yet MMP-1 and MMP-3 mRNA were commonly observed. TIMP-2 mR NA was also strongly expressed compared to TIMP-1. It was thus demonst rated that MMPs and TIMPs were produced locally in the cemented tissue of THA loosening. These findings may suggest that MMPs and TIMPs expr essed around the implants play a critical role in the progression of a septic loosening of THA. (C) 1996 John Wiley & Sons, Inc.