Indomethacin induces differential effects on in vitro endochondral ossification depending on the chondrocyte's differentiation stage.
Heterotopic ossification (HO) is the abnormal formation of bone in soft tissues and is a frequent complication of hip replacement surgery. Heterotopic ossifications are described to develop via endochondral ossification and standard treatment is administration of indomethacin. It is currently unknown how indomethacin influences heterotopic ossification on a molecular level; therefore, we aimed to determine whether indomethacin might influence heterotopic ossification via impairing the chondrogenic phase of endochondral ossification. Progenitor cell models differentiating in the chondrogenic lineage (ATDC5, primary human bone marrow stem cells and ex vivo periosteal agarose cultures) were treated with increasing concentrations of indomethacin and a decrease in gene- and protein expression of chondrogenic and hypertrophic markers (measured by RT-qPCR and immunoblotting) as well as decreased glycosamino-glycan content (by alcian blue histochemistry) was observed. Even when hypertrophic differentiation was provoked, the addition of indomethacin resulted in decreased hypertrophic marker expression. Interestingly, when mature chondrocytes were treated with indomethacin, a clear increase in collagen type 2 expression was observed. Similarly, when ATDC5 cells and bone marrow stem cells were pre-differentiated to obtain a chondrocyte phenotype and indomethacin was added from this time point onward, low concentrations of indomethacin also resulted in increased chondrogenic differentiation. Indomethacin induces differential effects on in vitro endochondral ossification, depending on the chondrocyte's differentiation stage, with complete inhibition of chondrogenic differentiation as the most pronounced action. This observation may provide a rational behind the elusive mode of action of indomethacin in the treatment of heterotopic ossifications. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:847-857, 2017.
Department of Orthopaedic Surgery, Caphri School for Public Health and Primary Care, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
Marjolein M J
MMJ
Caron
Department of Orthopaedic Surgery, Caphri School for Public Health and Primary Care, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
Pieter J
PJ
Emans
Department of Orthopaedic Surgery, Caphri School for Public Health and Primary Care, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
Andy
A
Cremers
Department of Orthopaedic Surgery, Caphri School for Public Health and Primary Care, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
Don A M
DAM
Surtel
Department of Orthopaedic Surgery, Caphri School for Public Health and Primary Care, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
Lodewijk W
LW
van Rhijn
Department of Orthopaedic Surgery, Caphri School for Public Health and Primary Care, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
Tim J M
TJM
Welting
D000469:Alkaline Phosphatase / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D019644:Arthroplasty, Replacement, Hip; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation; D019070:Cell Lineage; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology*; D020219:Chondrogenesis / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D006025:Glycosaminoglycans / Q000737:chemistry; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology*; D010012:Osteogenesis; D010521:Periosteum / Q000737:chemistry; D060888:Real-Time Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism
D000894:Anti-Inflammatory Agents, Non-Steroidal; D004268:DNA-Binding Proteins; D006025:Glycosaminoglycans; C087296:TRIM29 protein, human; D014157:Transcription Factors; D000469:Alkaline Phosphatase; D015232:Dinoprostone; D007213:Indomethacin
chondrogenic differentiation; endochondral ossification; heterotopic ossification; indomethacin