Evaluation of the in vitro cell-material interactions and in vivo osteo-integration of a spinal acrylic bone cement

Abstract

Introduction Polymethylmethacrylate bone cements have proven performance in arthroplasty and represent a common bone filler, e.g. in vertebroplasty. However, acrylic cements are still subject to controversy concerning their exothermic reaction and osteo-integration potential. Therefore, we submitted a highly filled acrylic cement to a systematic investigation on the cell-material and tissueimplant response in vitro and in vivo. Materials and methods Cured Vertecem V? Cements were characterized by electron microscopy. Human bone marrow-derived mesenchymal stem cell morphology, growth and differentiation on the cured cement were followed for 28 days in vitro. The uncured cement was injected in an ovine cancellous bone defect and analysed 4 and 26 weeks post-implantation. Results The rough surface of the cement allowed for good stem cells adhesion in vitro. Up-regulation of alkaline phosphatase was detected after 8 days of incubation. No adverse local effects were observed macroscopically and microscopically following 4 and 26 weeks of implantation of the cement into drill-hole defects in ovine distal femoral epiphysis. Direct bone apposition onto the implant surface was observed resulting in extended signs of osteo-integration over time (35.2 ± 24.2% and 88.8 ± 8.8% at week 4 and 26, respectively). Conclusion Contrary to the established opinion concerning bony tissue response to implanted acrylic bone cements, we observed an early cell-implant in vitro interaction leading to cell growth and differentiation and significant signs of osteo-integration for this acrylic cement using standardized methods. Few outlined limitations, such as the use of low cement volumes, have to be considered in the interpretation of the study results.

In Vitro and In Vivo Characterization of Premixed PMMA-CaP Composite Bone Cements

“…Bioactive fixation requires an interaction with surrounding cells. To introduce osseointegrative characteristics, composite cements were developed with a bioactive CaP phase. ,, CaP bioceramics have shown the ability to chemically bond with bone through physicochemical and enzymatic interactions. ,,, Diffusion and ion exchange are the main mechanisms through which the CaP phase can start initial interactions with the biological environment. , Depending on their calcium to phosphate ratios, CaP bioceramics can vary in their solubility. , In this study we have chosen HA and Brushite, which are the least soluble and most soluble forms of CaP cements, respectively. Protein interactions with the surface can also add to the dissolution of the CaP phase .…”

“…It is important to point out that a small animal model was chosen for this study because this was the first time this cement is tested in vivo, and thus data collected with this model will provide important data for the design of a future large animal model. The premixed composite cements were developed for use in vertebroplasty and were compared to PMMA-K accordingly as it is indicated for use in vertebral compression fracture augmentation and is popular among many clinicians, however PMMA-K is an acrylic cement and it would have been beneficial to have a commercially available composite cement for comparison. − However, PMMA-K has a larger number of published studies and clinical data compared to composite cements, and was used as control in previously published studies on the premixed cement system. − The rat tibia defect model provides a suitable load bearing environment during the healing process, however does not mimic cement injection into a complex trabecular structure like a human vertebral body (VB). The cement–bone interface will show proper interdigitation due to overpacking, which may not be the case during cement injection into a VB.…”

“…Commercially available PMMA-CaP cement such as Vertecem V+, a highly filled cement containing 40% w/total w zirconium dioxide and 15% w/total w hydroxyapatite, was investigated in vitro and in an animal model. Results showed cell-cement interaction in vitro with cell growth and differentiation followed by signs of osseointegration when implanted in an animal model . However, a limitation that could be expected from the addition of a calcium phosphate phase in an acrylic matrix is deterioration of the cement mechanical strength, handling and injectability, especially at high concentrations. , The introduction of high CaP concentrations in traditional powder-liquid acrylic cements may lead to filler clumping due to inadequate mixing.…”

Polymethyl methacrylate does not adversely affect the osteogenic potential of human adipose stem cells or primary osteoblasts

“…Mesenchymal stem cells (MSCs) and osteoblasts present within the tissue surrounding a bone defect are potentially exposed to cytotoxic factors leaching from the implanted PMMA. In vivo, MSCs migrate to the implant site, where they differentiate into an osteoblastic phenotype (Verrier et al, ). PMMA particles have been shown to inhibit osteoblast proliferation and collagen synthesis which may result in reduced periprosthetic bone formation, whereas PMMA particles stimulate osteocalcin and IL‐6 synthesis, known to stimulate bone resorption (Ishida & Amano, ; Kudo et al, ; Zambonin, Colucci, Cantatore, & Grano, ).…”

Acrylic Bone Cements: The Role of Nanotechnology in Improving Osteointegration and Tunable Mechanical Properties

“…The use of acrylic bone cements present disadvantages including high polymerization temperature, neurotoxicity of the monomer and lack of osteointegration due to their bioinert nature, i.e., it does not resorb or allow bone replacement. It is therefore encapsulated by fibrous tissue, 21 23 24 causing instability and movements at the bone cement-prosthesis interfaces, which are considered the weak-link-zones. These micromovements can accelerate aseptic loosening, causing a failure in the cemented Delivered by Publishing Technology to: Rice University, Fondren Library IP: 212.…”