scholarly journals Combinatorial morphogenetic and mechanical cues to mimic bone development for defect repair

2019 ◽  
Author(s):  
S. Herberg ◽  
A. M. McDermott ◽  
P. N. Dang ◽  
D. S. Alt ◽  
R. Tang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Bone Formation ◽  
Mechanical Loading ◽  
Endochondral Ossification ◽  
Bone Development ◽  
Human Mesenchymal Stem Cell ◽  
Bone Defects ◽  
Mechanical Environment ◽  
Tgf Β1

AbstractEndochondral ossification during long bone development and natural fracture healing initiates by mesenchymal cell condensation and is directed by local morphogen signals and mechanical cues. Here, we aimed to mimic these developmental conditions for regeneration of large bone defects. We hypothesized that engineered human mesenchymal stem cell (hMSC) condensations with in situ presentation of transforming growth factor-β1 (TGF-β1) and/or bone morphogenetic protein-2 (BMP-2) from encapsulated microparticles would promote endochondral regeneration of critical-sized rat femoral bone defects in a manner dependent on the in vivo mechanical environment. Mesenchymal condensations induced bone formation dependent on morphogen presentation, with dual BMP-2 + TGF-β1 fully restoring mechanical bone function by week 12. In vivo ambulatory mechanical loading, initiated at week 4 by delayed unlocking of compliant fixation plates, significantly enhanced the bone formation rate in the four weeks after load initiation in the dual morphogen group. In vitro, local presentation of either BMP-2 alone or BMP-2 + TGF-β1 initiated endochondral lineage commitment of mesenchymal condensations, inducing both chondrogenic and osteogenic gene expression through SMAD3 and SMAD5 signaling. In vivo, however, endochondral cartilage formation was evident only in the BMP-2 + TGF-β1 group and was enhanced by mechanical loading. The degree of bone formation was comparable to BMP-2 soaked on collagen but without the ectopic bone formation that limits the clinical efficacy of BMP-2/collagen. In contrast, mechanical loading had no effect on autograft-mediated repair. Together, this study demonstrates a biomimetic template for recapitulating developmental morphogenic and mechanical cues in vivo for tissue engineering.One Sentence SummaryMimicking aspects of the cellular, biochemical, and mechanical environment during early limb development, chondrogenically-primed human mesenchymal stem cell condensations promoted functional healing of critical-sized femoral defects via endochondral ossification, and healing rate and extent was a function of the in vivo mechanical environment.

scholarly journals Recapitulating bone development for tissue regeneration through engineered mesenchymal condensations and mechanical cues

2017 ◽  
Author(s):  
Anna M. McDermott ◽  
Samuel Herberg ◽  
Devon E. Mason ◽  
Hope B. Pearson ◽  
James H. Dawahare ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Formation ◽  
Mechanical Loading ◽  
Endochondral Ossification ◽  
Bone Development ◽  
Bone Defects ◽  
Limb Bud ◽  
Large Bone ◽  
Large Bone Defects

ABSTRACTLarge bone defects cannot heal without intervention and have high complication rates even with the best treatments available. In contrast, bone fractures naturally healing with high success rates by recapitulating the process of bone development through endochondral ossification.1 Endochondral tissue engineering may represent a promising paradigm, but large bone defects are unable to naturally form a callus. We engineered mesenchymal condensations featuring local morphogen presentation (TGF-β1) to mimic the cellular organization and lineage progression of the early limb bud. As mechanical forces are 2,3 critical for proper endochondral ossification during bone morphogenesis2,3 and fracture healing, we hypothesized that mechanical cues would be important for endochondral regeneration.4,5 Here, using fixation plates that modulate ambulatory load transfer through dynamic tuning of axial compliance, we found that in vivo mechanical loading was necessary to restore bone function to large bone defects through endochondral ossification. Endochondral regeneration produced zonal cartilage and primary spongiosa mimetic of the native growth plate. Live human chondrocytes contributed to endochondral regeneration in vivo, while cell devitalization prior to condensation transplantation abrogated bone formation. Mechanical loading induced regeneration comparable to high-dose BMP-2 delivery, but without heterotopic bone formation and with order-of-magnitude greater mechanosensitivity.6–8In vitro, mechanical loading promoted chondrogenesis, and upregulated pericellular collagen 6 deposition and angiogenic gene expression. Consistently, in vivo mechanical loading regulated cartilage formation and neovascular invasion dependent on load timing. Together, this study represents the first demonstration of the effects of mechanical loading on transplanted cell-mediated bone defect regeneration, and provides a new template for recapitulating developmental programs for tissue engineering.

scholarly journals Scaffold-free human mesenchymal stem cell construct geometry regulates long bone regeneration

2019 ◽  
Author(s):  
Samuel Herberg ◽  
Daniel Varghai ◽  
Daniel S. Alt ◽  
Phuong N. Dang ◽  
Honghyun Park ◽  
...  
Keyword(s):  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Bone Regeneration ◽  
Endochondral Ossification ◽  
Human Mesenchymal Stem Cell ◽  
Long Bone ◽  
Developmental Programs ◽  
Mechanical Environment ◽  
Tgf Β1

AbstractScaffold-based bone tissue engineering approaches frequently induce repair processes dissimilar to normal developmental programs. In contrast, biomimetic strategies aim to recapitulate aspects of development through cellular self-organization, morphogenetic pathway activation, and mechanical cues. This may improve regenerative outcome in large long bone defects that cannot heal on their own; however, no study to date has investigated the role of scaffold-free construct geometry, in this case tubes mimicking long bone diaphyses, on bone regeneration. We hypothesized that microparticle-mediated in situ presentation of transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) to engineered human mesenchymal stem cell (hMSC) tubes induces the endochondral cascade, and that TGF-β1 + BMP-2-presenting hMSC tubes facilitate enhanced endochondral healing of critical-sized femoral segmental defects under delayed in vivo mechanical loading conditions compared to loosely-packed hMSC sheets. Here, localized morphogen presentation imparted early chondrogenic lineage priming, and stimulated robust endochondral differentiation of hMSC tubes in vitro. In an ectopic environment, hMSC tubes formed a cartilage template that was actively remodeled into trabecular bone through endochondral ossification without lengthy predifferentiation. Similarly, hMSC tubes stimulated in vivo cartilage and bone formation and more robust healing in femoral defects compared to hMSC sheets. New bone was formed through endochondral ossification in both groups; however, only hMSC tubes induced regenerate tissue partially resembling normal growth plate architecture. Together, this study demonstrates the interaction between mesenchymal cell condensation geometry, bioavailability of multiple morphogens, and defined in vivo mechanical environment to recapitulate developmental programs for biomimetic bone tissue engineering.Significance StatementEngineered bone constructs must be capable of withstanding and adapting to harsh conditions in a defect site upon implantation, and can be designed to facilitate repair processes that resemble normal developmental programs. Self-assembled tubular human mesenchymal stem cell constructs were engineered to resemble the geometry of long bone diaphyses. By mimicking the cellular, biochemical, and mechanical environment of the endochondral ossification process during embryonic development, successful healing of large femoral segmental defects upon implantation was achieved and the extent was construct geometry dependent. Importantly, results were obtained without a supporting scaffold or lengthy predifferentiation of the tubular constructs. This indicates that adult stem/progenitor cells retain features of embryonic mesenchyme, and supports the concept of developmental engineering for bone regeneration approaches.

scholarly journals Glycosaminoglycan Mimetic Associated to Human Mesenchymal Stem Cell-Based Scaffolds Inhibit Ectopic Bone Formation, but Induce Angiogenesis In Vivo

2013 ◽  
Vol 19 (13-14) ◽  
pp. 1641-1653 ◽  
Author(s):  
Guilhem Frescaline ◽  
Thibault Bouderlique ◽  
Leyya Mansoor ◽  
Gilles Carpentier ◽  
Brigitte Baroukh ◽  
...  
Keyword(s):  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Bone Formation ◽  
Human Mesenchymal Stem Cell ◽  
Ectopic Bone Formation ◽  
Ectopic Bone

scholarly journals Combinatorial morphogenetic and mechanical cues to mimic bone development for defect repair

2019 ◽  
Vol 5 (8) ◽  
pp. eaax2476 ◽  
Author(s):  
S. Herberg ◽  
A. M. McDermott ◽  
P. N. Dang ◽  
D. S. Alt ◽  
R. Tang ◽  
...  
Keyword(s):  
Bone Formation ◽  
Transforming Growth Factor ◽  
Bone Development ◽  
Formation Rate ◽  
Natural Fracture ◽  
Bone Morphogenetic Protein 2 ◽  
Long Bone ◽  
Bone Formation Rate ◽  
Tgf Β1

Endochondral ossification during long bone development and natural fracture healing initiates by mesenchymal cell condensation, directed by local morphogen signals and mechanical cues. Here, we aimed to mimic development for regeneration of large bone defects. We hypothesized that engineered human mesenchymal condensations presenting transforming growth factor–β1 (TGF-β1) and/or bone morphogenetic protein-2 (BMP-2) from encapsulated microparticles promotes endochondral defect regeneration contingent on in vivo mechanical cues. Mesenchymal condensations induced bone formation dependent on morphogen presentation, with BMP-2 + TGF-β1 fully restoring mechanical function. Delayed in vivo ambulatory loading significantly enhanced the bone formation rate in the dual morphogen group. In vitro, BMP-2 or BMP-2 + TGF-β1 initiated robust endochondral lineage commitment. In vivo, however, extensive cartilage formation was evident predominantly in the BMP-2 + TGF-β1 group, enhanced by mechanical loading. Together, this study demonstrates a biomimetic template for recapitulating developmental morphogenic and mechanical cues in vivo for tissue engineering.

scholarly journals Scaffold-free human mesenchymal stem cell construct geometry regulates long bone regeneration

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Samuel Herberg ◽  
Daniel Varghai ◽  
Daniel S. Alt ◽  
Phuong N. Dang ◽  
Honghyun Park ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Human Mesenchymal Stem Cell ◽  
Functional Restoration ◽  
Defect Healing ◽  
Tgf Β1

AbstractBiomimetic bone tissue engineering strategies partially recapitulate development. We recently showed functional restoration of femoral defects using scaffold-free human mesenchymal stem cell (hMSC) condensates featuring localized morphogen presentation with delayed in vivo mechanical loading. Possible effects of construct geometry on healing outcome remain unclear. Here, we hypothesized that localized presentation of transforming growth factor (TGF)-β1 and bone morphogenetic protein (BMP)-2 to engineered hMSC tubes mimicking femoral diaphyses induces endochondral ossification, and that TGF-β1 + BMP-2-presenting hMSC tubes enhance defect healing with delayed in vivo loading vs. loosely packed hMSC sheets. Localized morphogen presentation stimulated chondrogenic priming/endochondral differentiation in vitro. Subcutaneously, hMSC tubes formed cartilage templates that underwent bony remodeling. Orthotopically, hMSC tubes stimulated more robust endochondral defect healing vs. hMSC sheets. Tissue resembling normal growth plate was observed with negligible ectopic bone. This study demonstrates interactions between hMSC condensation geometry, morphogen bioavailability, and mechanical cues to recapitulate development for biomimetic bone tissue engineering.

scholarly journals Effects of chondrogenic priming duration on mechanoregulation of engineered cartilage anlagen

2020 ◽  
Author(s):  
Anna M. McDermott ◽  
Emily A. Eastburn ◽  
Daniel J. Kelly ◽  
Joel D. Boerckel
Keyword(s):  
Dynamic Loading ◽  
Mechanical Loading ◽  
Endochondral Ossification ◽  
Bone Development ◽  
Mechanical Compression ◽  
Dynamic Mechanical ◽  
Matrix Deposition ◽  
Static Conditions

AbstractBone development and repair occur by endochondral ossification of a cartilage anlage, or template. Endochondral ossification is regulated by mechanical cues. Recently, we found that in vivo mechanical loading promoted regeneration of large bone defects through endochondral ossification, in a manner dependent on the timing of load initiation. Here, we have developed an in vitro model of the cartilage anlage to test whether the chondrogenic differentiation state alters the response to dynamic mechanical compression. We cultured human bone marrow stromal cells (hMSCs) at high cell density in fibrin hydrogels under chondrogenic priming conditions for periods of 0, 2, 4, or 6 weeks prior to two weeks of dynamic mechanical loading. Samples were evaluated by biomechanical testing, biochemical analysis of collagen and glycosaminoglycan (GAG) deposition, gene expression analysis, and immunohistological analysis, in comparison to time-matched controls cultured under static conditions. We found that dynamic loading increased the mechanical stiffness of engineered anlagen in a manner dependent on the duration of chondrogenic priming prior to load initiation. For chondrogenic priming times of 2 weeks or greater, dynamic loading enhanced the expression of type II collagen and aggrecan, although no significant changes in overall levels of matrix deposition was observed. For priming periods less than 4 weeks, dynamic loading generally supressed markers of hypertrophy and osteogenesis, although this was not observed if the priming period was extended to 6 weeks, where loading instead enhanced the expression of type X collagen. Taken together, these data demonstrate that the duration of chondrogenic priming regulates the endochondral response to dynamic mechanical compression in vitro, which may contribute to the effects of mechanical loading on endochondral bone development, repair, and regeneration in vivo.

scholarly journals Recapitulating bone development through engineered mesenchymal condensations and mechanical cues for tissue regeneration

2019 ◽  
Vol 11 (495) ◽  
pp. eaav7756 ◽  
Author(s):  
Anna M. McDermott ◽  
Samuel Herberg ◽  
Devon E. Mason ◽  
Joseph M. Collins ◽  
Hope B. Pearson ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Formation ◽  
Mechanical Loading ◽  
Bone Defect ◽  
Bone Development ◽  
Limb Bud ◽  
Mechanical Forces ◽  
Endochondral Bone ◽  
Large Bone

Large bone defects cannot form a callus and exhibit high complication rates even with the best treatment strategies available. Tissue engineering approaches often use scaffolds designed to match the properties of mature bone. However, natural fracture healing is most efficient when it recapitulates development, forming bone via a cartilage intermediate (endochondral ossification). Because mechanical forces are critical for proper endochondral bone development and fracture repair, we hypothesized that recapitulating developmental mechanical forces would be essential for large bone defect regeneration in rats. Here, we engineered mesenchymal condensations that mimic the cellular organization and lineage progression of the early limb bud in response to local transforming growth factor–β1 presentation from incorporated gelatin microspheres. We then controlled mechanical loading in vivo by dynamically tuning fixator compliance. Mechanical loading enhanced mesenchymal condensation–induced endochondral bone formation in vivo, restoring functional bone properties when load initiation was delayed to week 4 after defect formation. Live cell transplantation produced zonal human cartilage and primary spongiosa mimetic of the native growth plate, whereas condensation devitalization before transplantation abrogated bone formation. Mechanical loading induced regeneration comparable to high-dose bone morphogenetic protein-2 delivery, but without heterotopic bone formation and with order-of-magnitude greater mechanosensitivity. In vitro, mechanical loading promoted chondrogenesis and up-regulated pericellular matrix deposition and angiogenic gene expression. In vivo, mechanical loading regulated cartilage formation and neovascular invasion, dependent on load timing. This study establishes mechanical cues as key regulators of endochondral bone defect regeneration and provides a paradigm for recapitulating developmental programs for tissue engineering.

scholarly journals Designing Topographically Textured Microparticles for Induction and Modulation of Osteogenesis in Mesenchymal Stem Cell Engineering

2020 ◽  
Author(s):  
Mahetab H. Amer ◽  
Marta Alvarez-Paino ◽  
Jane McLaren ◽  
Francesco Pappalardo ◽  
Sara Trujillo ◽  
...  
Keyword(s):  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Cell Fate ◽  
Cell Attachment ◽  
Bone Development ◽  
Human Mesenchymal Stem Cell ◽  
Stem Cell Engineering ◽  
Osteogenic Response ◽  
Altered Gene

AbstractMesenchymal stem cells have been the focus of intense research in bone development and regeneration. We demonstrate the potential of microparticles as modulating moieties of osteogenic response by utilizing their architectural features. Topographically textured microparticles of varying microscale features were produced by exploiting phase-separation of a readily-soluble sacrificial component from polylactic acid. The influence of varying topographical features on primary human mesenchymal stem cell attachment, proliferation and markers of osteogenesis was investigated. In the absence of osteoinductive supplements, cells cultured on textured microparticles exhibited notably increased expression of osteogenic markers relative to conventional smooth microparticles. They also exhibited varying morphological, attachment and proliferation responses. Significantly altered gene expression and metabolic profiles were observed, with varying histological characteristics in vivo. This study highlights how tailoring topographical design offers cell-instructive 3D microenvironments which allow manipulation of stem cell fate by eliciting the desired downstream response without use of exogenous osteoinductive factors.

scholarly journals Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Philipp S. Lienemann ◽  
Stéphanie Metzger ◽  
Anna-Sofia Kiveliö ◽  
Alain Blanc ◽  
Panagiota Papageorgiou ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Bone Formation ◽  
Bone Regeneration ◽  
Bone Defects ◽  
Histological Evaluation ◽  
Biological Processes ◽  
Micro Ct ◽  
Pinhole Spect

Abstract Over the last decades, great strides were made in the development of novel implants for the treatment of bone defects. The increasing versatility and complexity of these implant designs request for concurrent advances in means to assess in vivo the course of induced bone formation in preclinical models. Since its discovery, micro-computed tomography (micro-CT) has excelled as powerful high-resolution technique for non-invasive assessment of newly formed bone tissue. However, micro-CT fails to provide spatiotemporal information on biological processes ongoing during bone regeneration. Conversely, due to the versatile applicability and cost-effectiveness, single photon emission computed tomography (SPECT) would be an ideal technique for assessing such biological processes with high sensitivity and for nuclear imaging comparably high resolution (<1 mm). Herein, we employ modular designed poly(ethylene glycol)-based hydrogels that release bone morphogenetic protein to guide the healing of critical sized calvarial bone defects. By combined in vivo longitudinal multi-pinhole SPECT and micro-CT evaluations we determine the spatiotemporal course of bone formation and remodeling within this synthetic hydrogel implant. End point evaluations by high resolution micro-CT and histological evaluation confirm the value of this approach to follow and optimize bone-inducing biomaterials.

scholarly journals Biocompatibility and Bone Formation of Flexible, Cotton Wool-like PLGA/Calcium Phosphate Nanocomposites in Sheep

2011 ◽  
Vol 5 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Oliver D Schneider ◽  
Dirk Mohn ◽  
Roland Fuhrer ◽  
Karina Klein ◽  
Käthi Kämpf ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Bone Formation ◽  
Antimicrobial Properties ◽  
Drill Hole ◽  
Bone Defects ◽  
Long Bone ◽  
Minimal Amount ◽  
Cotton Wool

Background: The purpose of this preliminary study was to assess the in vivo performance of synthetic, cotton wool-like nanocomposites consisting of a biodegradable poly(lactide-co-glycolide) fibrous matrix and containing either calcium phosphate nanoparticles (PLGA/CaP 60:40) or silver doped CaP nanoparticles (PLGA/Ag-CaP 60:40). Besides its extraordinary in vitro bioactivity the latter biomaterial (0.4 wt% total silver concentration) provides additional antimicrobial properties for treating bone defects exposed to microorganisms. Materials and Methods: Both flexible artificial bone substitutes were implanted into totally 16 epiphyseal and metaphyseal drill hole defects of long bone in sheep and followed for 8 weeks. Histological and histomorphological analyses were conducted to evaluate the biocompatibility and bone formation applying a score system. The influence of silver on the in vivo performance was further investigated. Results: Semi-quantitative evaluation of histology sections showed for both implant materials an excellent biocompatibility and bone healing with no resorption in the adjacent bone. No signs of inflammation were detectable, either macroscopically or microscopically, as was evident in 5 µm plastic sections by the minimal amount of inflammatory cells. The fibrous biomaterials enabled bone formation directly in the centre of the former defect. The area fraction of new bone formation as determined histomorphometrically after 8 weeks implantation was very similar with 20.5 ± 11.2 % and 22.5 ± 9.2 % for PLGA/CaP and PLGA/Ag-CaP, respectively. Conclusions: The cotton wool-like bone substitute material is easily applicable, biocompatible and might be beneficial in minimal invasive surgery for treating bone defects.

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