Alendronate stimulates osteoprotegerin expression in fibroblasts from periprosthetic membrane.
OBJECTIVE
Aseptic loosening of an implant after total joint arthroplasty is still a major complication that results from periprosthetic osteolysis. Fibroblasts in the interface membrane express receptor activator of nuclear factor kappa B ligand (RANKL) and stimulate osteoclast formation. Studies demonstrate that through the control of osteoclastic bone loss bisphosphonates inhibit wear particle-induced bone resorption around total hip arthroplasty. The majority of bisphosphonates studies have focused on their effects on osteoblasts and osteoclasts. Little attention has been paid to their action on fibroblasts.


METHODS
We isolated fibroblasts from the interface membrane that was obtained when revision hip arthroplasty was performed because of aseptic loosening. Fibroblasts were stimulated with alendronate. RANKL and osteoprotegerin (OPG) assays were performed using enzyme-linked immunosorbent assay kit and real time Reverse Transcription- Polymerase Chain Reaction (RT-PCR).


RESULTS
We found that alendronate stimulated OPG mRNA and protein expression in a time and dose dependent manner. By contrast, alendronate did not affect RANKL expression.


CONCLUSIONS
The results indicate that alendronate modulated OPG production by fibroblasts from periprosthetic membrane, which may prove helpful for the inhibition of bone loss during aseptic loosening following total joint arthroplasty.
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Yebin
Y
Qian
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Xian-long
XL
Zhang
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Yao
Y
Jiang
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Bing-fang
BF
Zeng
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Qi
Q
Wang
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Yunsu
Y
Chen
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Hao
H
Shen
Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - China.
Qiaojie
Q
Wang
D000368:Aged; D000369:Aged, 80 and over; D019386:Alendronate / Q000494:pharmacology*; D019644:Arthroplasty, Replacement, Hip; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D018929:Cell Culture Techniques; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology / Q000378:metabolism; D053244:Osteoprotegerin / Q000235:genetics / Q000378:metabolism*; D011475:Prosthesis Failure; D053245:RANK Ligand / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
D050071:Bone Density Conservation Agents; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D019386:Alendronate