Plasma levels of platelet-derived growth factor BB and transforming growth factor in patients with failed hip prostheses.
BACKGROUND
The role of growth factors in prosthesis loosening is unclear. We evaluated the levels of platelet-derived growth factor BB (PDGF-BB), transforming growth factors beta1 (TGF-beta1) and beta2 (TGF-beta2), both before and after activation, in patients with aseptic loosening of their hip prosthesis.


METHODS
26 patients with loosened hip implants were compared with 21 patients who had stable hip prostheses, and 28 patients undergoing primary hip replacement. The plasma levels of the growth factors were analyzed by enzyme immunoassay. TGF-beta1 and TGF-beta2 were determined both before and after activation.


RESULTS
Patients with aseptic loosening had significantly lower PDGF-BB levels than patients undergoing primary hip replacement, and significantly lower TGF-beta2 levels than patients with a stable implant. Patients with stable prostheses had significantly higher TGF-beta1 and TGF-beta2 levels than patients undergoing primary hip replacement.


CONCLUSIONS
It is possible that the prosthetic implant itself causes a local increase in PDGF-BB, TGF-beta1 and TGF-beta2, released by osteoblasts and other cells in the microenvironment. The plasma PDGF-BB measured does not correspond to local release, which is probably due to local consumption or degradation. The consumption of PDGF-BB is low in stable implants, and TGF-beta1 and TGF-beta2 levels increase during bone formation. In loosening, PDGF-BB consumption is higher and causes a significant reduction in plasma levels as compared to presurgery. The formation of poor-quality bone may be related to the scarce increase in TGF-beta1 and TGF-beta2. In conclusion, compared with patients with a stable implant, a reduction in bone-forming growth factors appears to occur in individuals with aseptic loosening.
Cenni
Elisabetta
E
Laboratory for Pathophysiology of Orthopedic Implants, Istituti Ortopedici Rizzoli, via di Barbiano 1/10, IT-40136 Bologna, Italy. elisabetta.cenni@ior.it
Savarino
Lucia
L
Antonioli
Diego
D
Pellacani
Andrea
A
Giunti
Armando
A
Baldini
Nicola
N
D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods; D000077214:Becaplermin; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects / Q000592:standards; D006801:Humans; D008297:Male; D008875:Middle Aged; D010982:Platelet-Derived Growth Factor / Q000032:analysis*; D011475:Prosthesis Failure; D020574:Proto-Oncogene Proteins c-sis; D016211:Transforming Growth Factor alpha / Q000097:blood*; D016212:Transforming Growth Factor beta / Q000097:blood*
D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D016211:Transforming Growth Factor alpha; D016212:Transforming Growth Factor beta; D000077214:Becaplermin