Volume 19, Issue 2 pp. 179-186
Article
Free Access

Effect of polymer molecular weight and addition of calcium stearate on response of MG63 osteoblast-like cells to UHMWPE particles

D. D. Dean

D. D. Dean

Department of Orthopaedics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Search for more papers by this author
C. H. Lohmann

C. H. Lohmann

Department of Orthopaedics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Department of Orthopaedics, Georg-August Universität, Göttingen, Germany

Search for more papers by this author
V. L. Sylvia

V. L. Sylvia

Department of Orthopaedics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Search for more papers by this author
G. Köster

G. Köster

Department of Orthopaedics, Georg-August Universität, Göttingen, Germany

Search for more papers by this author
Y. Liu

Y. Liu

Department of Orthopaedics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Search for more papers by this author
Z. Schwartz

Z. Schwartz

Department of Orthopaedics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Department of Periodontics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Department of Periodontology, Hebrew University Hadassah Faculty of Dental, Medicine, Jerusalem, Israel

Search for more papers by this author
B. D. Boyan

Corresponding Author

B. D. Boyan

Department of Orthopaedics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Department of Periodontics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Department of Biochemistry, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA

Department of Orthopaedics, University of Texas Health Science Center at San Antonio, Mail Code 7774, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA, Tel.: +1-210-567-6326; fax: +1-210-567-6295Search for more papers by this author
First published: 01 January 2006
Citations: 22

Abstract

Periprosthetic osteolysis and implant loosening is associated with the presence of ultrahigh molecular weight polyethylene (UHMWPE) wear debris particles. Osteoblast phenotypic expression in vitro is affected by UHMWPE particles, suggesting that bone formation may also be affected by wear debris. Here we tested the hypothesis that the response of osteoblasts to UHMWPE can be modified by changes in UHMWPE particle chemistry. We used four different commercially available preparations of GUR UHMWPE particles to determine if chemical composition (±Ca-stearate) or polymer molecular weight (3.1–4.2 million or 5.4–6.5 million g/mol) modulates osteoblast response. Particles were characterized by size distribution, morphology, and number of particles added to the culture medium. They had an average equivalent circle diameter ranging from 0.46–1.26 μm. MG63 cell response was assessed by measuring cell number, cellular and cell layer alkaline phosphatase, and prostaglandin E2 (PGE2) production. There were dose-dependent effects of the particles on cell response. Cell number and PGE2 production were increased, while alkaline phosphatase specific activity was decreased. In addition, there was a marked difference between cultures treated with particles containing Ca-stearate and as a function of polymer molecular weight. Particles of higher molecular weight caused a greater stimulation of proliferation and inhibition of alkaline phosphatase than particles of lower molecular weight. The presence of Castearate exerted a more pronounced depression of osteoblast phenotype as well as a significantly greater increase in PGE2 release by the cells. The present study shows that chemical composition and polymer molecular weight of UHMWPE are capable of modulating osteoblast response to particles. The results suggest that osteoblast differentiation is inhibited by UHMWPE particles, whereas cell proliferation and PGE2 production are stimulated. This may have direct effects on osteoblasts and bone formation, but also paracrine effects on cells of the monocytic lineage inducing bone resorption and promoting inflammation which may lead to aseptic loosening. The present results suggest that the cellular events in aseptic loosening may be modulated or even accelerated by changes in the composition of the UHMWPE used to fabricate implants. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.