Genomewide Molecular and Biologic Characterization of Biomembrane Formation Adjacent to a Methacrylate Spacer in the Rat Femoral Segmental Defect Model

Gruber, Helen E.; Gettys, F. Keith; Montijo, Harvey E.; Starman, James S.; Bayoumi, Essraa M.; Nelson, Kenneth J.; Hoelscher, Gretchen L.; Ramp, Warren K.; Zinchenko, Natalia; Ingram, Jane A.; Bosse, Michael J.; Kellam, James F

doi:10.1097/bot.0b013e3182691288

Cited by 37 publications

(62 citation statements)

References 19 publications

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“…As has been noted in basic science studies 21,22 and some case studies, 24 mineralized tissue will sometimes extend from the original cortical bone ends to encase the spacer. There were no differences between groups in maximal bone extent length (~1.7mm) or total bone volumes.…”

Section: Resultsmentioning

confidence: 95%

Masquelet Technique: Effects of Spacer Material and Micro-topography on Factor Expression and Bone Regeneration

et al. 2018

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We and others have shown that changing surface characteristics of the spacer implanted during the first Masquelet stage alters some aspects of membrane development. Previously we demonstrated that titanium spacers create membranes that are better barriers to movement of solutes >70kDa in size than polymethyl methacrylate (PMMA) induced-membranes, and roughening creates more mechanically compliant membranes. However, it is unclear if these alterations affect the membrane’s biochemical environment or bone regeneration during the second stage. Ten-week-old, male Sprague-Dawley rats underwent an initial surgery to create an externally stabilized 6mm femoral defect. PMMA or titanium spacers with smooth (~1um) or roughened (~8um) surfaces were implanted. Four weeks later, rats were either euthanized for membrane harvest or underwent the second Masquelet surgery. Titanium spacers induced thicker membranes that were similar in structure and biochemical expression. All membranes were bilayered with the inner layer having increased factor expression (BMP2, TGFβ, IL6, and VEGF). Roughening increased overall IL6 levels. Ten-weeks post-engraftment, PMMA-smooth induced membranes better supported bone regeneration (60% union). The other groups only had 1 or 2 that united (9–22%). There were no significant differences in any microCT or dynamic histology outcome. In conclusion, this study suggests that the membrane’s important function in the Masquelet technique is not simply as a barrier. There is likely a critical biochemical, cellular, or vascular component as well.

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Section: Resultsmentioning

confidence: 95%

Masquelet Technique: Effects of Spacer Material and Micro-topography on Factor Expression and Bone Regeneration

et al. 2018

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“…Other studies have characterized the induced membrane formed by PMMA in rat models . There are clear similarities between human and rat induced membrane with respect to timing of membrane formation, histological composition including osteoprogenitor cells, and presence of important growth factors such as transforming growth factor‐beta (TGF‐β), bone morphogenetic protein‐2 (BMP‐2), and vascular endothelial growth factor (VEGF) .…”

Section: Discussionmentioning

confidence: 99%

Preclinical induced membrane model to evaluate synthetic implants for healing critical bone defects without autograft

DeBaun

Stahl

Daoud

et al. 2018

Journal Orthopaedic Research

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Critical bone defects pose a formidable orthopaedic problem in patients with bone loss. We developed a preclinical model based on the induced membrane technique using a synthetic graft to replace autograft for healing critical bone defects. Additionally, we used a novel osteoconductive scaffold coupled with a synthetic membrane to evaluate the potential for single‐stage bone regeneration. Three experimental conditions were investigated in critical femoral defects in rats. Group A underwent a two‐stage procedure with insertion of a polymethylmethacrylate (PMMA) spacer followed by replacement with a 3D printed polycaprolactone(PCL)/β‐tricalcium phosphate (β‐TCP) osteoconductive scaffold after 4 weeks. Group B received a single‐stage PCL/β‐TCP scaffold wrapped in a PCL‐based microporous polymer film creating a synthetic membrane. Group C received a single‐stage bare PCL/β‐TCP scaffold. All groups were examined by serial radiographs for callus formation. After 12 weeks, the femurs were explanted and analyzed with micro‐CT and histology. Mean callus scores tended to be higher in Group A. Group A showed statistically significant greater bone formation on micro‐CT compared with other groups, although bone volume fraction was similar between groups. Histology results suggested extensive bone ingrowth and new bone formation within the macroporous scaffolds in all groups and cell infiltration into the microporous synthetic membrane. This study supports the use of a critical size femoral defect in rats as a suitable model for investigating modifications to the induced membrane technique without autograft harvest. Future investigations should focus on bioactive synthetic membranes coupled with growth factors for single‐stage bone healing. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

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“…This is an important finding in human biomembrane research and is similar to previous studies from our laboratory that have evaluated the properties of biomembranes formed in a rat segmental defect model. 24,25 …”

Section: Discussionmentioning

confidence: 99%

“…Results from age- and site-controlled small animal studies were previously reported by our group. 24,25 Another limitation of this study is that it has a relatively small sample size for the gene expression analyses. Although many of the differences in gene expression reached statistical significance, future studies with larger sample sizes are needed.…”

Section: Discussionmentioning

confidence: 99%

Osteogenic, stem cell and molecular characterisation of the human induced membrane from extremity bone defects

Ode

Hoelscher

et al. 2016

Bone & Joint Research

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ObjectivesThe biomembrane (induced membrane) formed around polymethylmethacrylate (PMMA) spacers has value in clinical applications for bone defect reconstruction. Few studies have evaluated its cellular, molecular or stem cell features. Our objective was to characterise induced membrane morphology, molecular features and osteogenic stem cell characteristics.MethodsFollowing Institutional Review Board approval, biomembrane specimens were obtained from 12 patient surgeries for management of segmental bony defects (mean patient age 40.7 years, standard deviation 14.4). Biomembranes from nine tibias and three femurs were processed for morphologic, molecular or stem cell analyses. Gene expression was determined using the Affymetrix GeneChip Operating Software (GCOS). Molecular analyses compared biomembrane gene expression patterns with a mineralising osteoblast culture, and gene expression in specimens with longer spacer duration (> 12 weeks) with specimens with shorter durations. Statistical analyses used the unpaired student t-test (two tailed; p < 0.05 was considered significant).ResultsAverage PMMA spacer in vivo time was 11.9 weeks (six to 18). Trabecular bone was present in 33.3% of the biomembrane specimens; bone presence did not correlate with spacer duration. Biomembrane morphology showed high vascularity and collagen content and positive staining for the key bone forming regulators, bone morphogenetic protein 2 (BMP2) and runt-related transcription factor 2 (RUNX2). Positive differentiation of cultured biomembrane cells for osteogenesis was found in cells from patients with PMMA present for six to 17 weeks. Stem cell differentiation showed greater variability in pluripotency for osteogenic potential (70.0%) compared with chondrogenic or adipogenic potentials (100% and 90.0%, respectively). Significant upregulation of BMP2 and 6, numerous collagens, and bone gla protein was present in biomembrane compared with the cultured cell line. Biomembranes with longer resident PMMA spacer duration (vs those with shorter residence) showed significant upregulation of bone-related, stem cell, and vascular-related genes.ConclusionThe biomembrane technique is gaining favour in the management of complicated bone defects. Novel data on biological mechanisms provide improved understanding of the biomembrane’s osteogenic potential and molecular properties.Cite this article: Dr H. E. Gruber. Osteogenic, stem cell and molecular characterisation of the human induced membrane from extremity bone defects. Bone Joint Res 2016;5:106–115. DOI: 10.1302/2046-3758.54.2000483.

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Genomewide Molecular and Biologic Characterization of Biomembrane Formation Adjacent to a Methacrylate Spacer in the Rat Femoral Segmental Defect Model

Cited by 37 publications

References 19 publications

Masquelet Technique: Effects of Spacer Material and Micro-topography on Factor Expression and Bone Regeneration

Masquelet Technique: Effects of Spacer Material and Micro-topography on Factor Expression and Bone Regeneration

Preclinical induced membrane model to evaluate synthetic implants for healing critical bone defects without autograft

Osteogenic, stem cell and molecular characterisation of the human induced membrane from extremity bone defects

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