References of "Van Oosterwyck, Hans"
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See detailCross-talk Modeling of Wnt, BMP and ERK Pathways during Osteochondrogenic Differentiation
Geris, Liesbet ULg; Vandeput, M.; Roberts, S. et al

in Proceedings of the TERMIS-EU meeting (2010, June)

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See detailConnecting biology and mechanics in fracture healing: an integrated mathematical modeling framework for the study of nonunions
Geris, Liesbet ULg; Vander Sloten, Jos; Van Oosterwyck, Hans

in Biomechanics & Modeling in Mechanobiology (2010), 9(6), 713-724

Both mechanical and biological factors play an important role in normal as well as impaired fracture healing. This study aims to provide a mathematical framework in which both regulatory mechanisms are ... [more ▼]

Both mechanical and biological factors play an important role in normal as well as impaired fracture healing. This study aims to provide a mathematical framework in which both regulatory mechanisms are included. Mechanics and biology are coupled by making certain parameters of a previously established bioregulatory model dependent on local mechanical stimuli. To illustrate the potential added value of such a framework, this coupled model was applied to investigate whether local mechanical stimuli influencing only the angiogenic process can explain normal healing as well as overload-induced nonunion development. Simulation results showed that mechanics acting directly on angiogenesis alone was not able to predict the formation of overload-induced onunions. However, the direct action of mechanics on both angiogenesis and osteogenesis was able to predict overload-induced nonunion formation, confirming the hypotheses of several experimental studies investigating the interconnection between angiogenesis and osteogenesis. This study shows that mathematical models can assist in testing hypothesis on the nature of the interaction between biology and mechanics. [less ▲]

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See detailMechanical loading affects angiogenesis and osteogenesis in an in vivo bone chamber: a modeling study.
Geris, Liesbet ULg; Vandamme, Katleen; Naert, Ignace et al

in Tissue Engineering. Part A (2010), 16(11), 3353-3361

Despite a myriad of studies confirming the interaction between biology and mechanics, the exact nature of the main mechanical stimuli and their influence on the bone regeneration processes are still ... [more ▼]

Despite a myriad of studies confirming the interaction between biology and mechanics, the exact nature of the main mechanical stimuli and their influence on the bone regeneration processes are still unclear. The hypothesis of this study was that the outcome of peri-implant healing under different implant loading regimens can be explained by the influence of fluid flow on the combination of angiogenesis and osteogenesis through its influence on cell proliferation and differentiation. To investigate this hypothesis a mathematical model of bone regeneration was applied to simulate the peri-implant healing in an in vivo repeated sampling bone chamber for different axial micromechanical implant loading regimes. When mechanical loading was modeled to influence both osteogenic and angiogenic processes, a good agreement was observed between simulations and experiments concerning the amount of bone in the bone chamber, its radial and longitudinal distribution, and the bone-implant contact for different implant displacement magnitudes. [less ▲]

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See detailTowards a quantitative understanding of oxygen tension and cell density evolution in fibrin hydrogels
Demol, Jan; Lambrechts, Dennis; Geris, Liesbet ULg et al

in Biomaterials (2010), 32(1), 107-118

The in vitro culture of hydrogel-based constructs above a critical size is accompanied by problems of unequal cell distribution when diffusion is the primary mode of oxygen transfer. In this study, an ... [more ▼]

The in vitro culture of hydrogel-based constructs above a critical size is accompanied by problems of unequal cell distribution when diffusion is the primary mode of oxygen transfer. In this study, an experimentally informed mathematical model was developed to relate cell proliferation and death inside fibrin hydrogels to the local oxygen tension in a quantitative manner. The predictive capacity of the resulting model was tested by comparing its outcomes to the density, distribution and viability of human periosteum derived cells (hPDCs) that were cultured inside fibrin hydrogels in vitro. The model was able to reproduce important experimental findings, such as the formation of a multilayered cell sheet at the hydrogel periphery and the occurrence of a cell density gradient throughout the hydrogel. In addition, the model demonstrated that cell culture in fibrin hydrogels can lead to complete anoxia in the centre of the hydrogel for realistic values of oxygen diffusion and consumption. A sensitivity analysis also identified these two parameters, together with the proliferation parameters of the encapsulated cells, as the governing parameters for the occurrence of anoxia. In conclusion, this study indicates that mathematical models can help to better understand oxygen transport limitations and its influence on cell behaviour during the in vitro culture of cellseeded hydrogels. [less ▲]

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See detailIn vivo, in vitro, in silico: computational tools for tissue engineering
Van Oosterwyck, Hans; Truscello, S.; Demol, Jan et al

in proceedings of the 2nd International Conference on Innovation for Sustainable Production i-SUP (2010)

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See detailOptimizing The Micro-Environment In A Tissue Engineering Scaffold: A Computational Approach
Van Oosterwyck, Hans; Truscello, S.; Demol, J. et al

in proceedings of the Materialise World Conference (2010)

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See detailExperimental and computational study of the correlation between oxygen tension, cell viability and proliferation in fibrin hydrogels
Demol, J.; Lambrechts, D.; Geris, Liesbet ULg et al

in Proceedings of the 17th conference of the European Society of Biomechanics (2010)

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See detailA hybrid model for the simulation of angiogenesis during bone fracture healing
Geris, Liesbet ULg; Peiffer, Veronique; Gerisch, Alf et al

in Proceedings of the 17th conference of the European Society of Biomechanics (2010)

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See detailCrosstalk Modeling of Wnt, BMP and ERK Pathways during osteochondrogenic differentiation
Geris, Liesbet ULg; Vandeput, Maarten; Roberts, Scott et al

in proceedings of the International Symposium on Biomechanics and Biology of Bone Regeneration “From Functional Assessment To Guided Tissue Formation (2009, November)

The in vitro engineering of tissues may be achieved by mimicking in vivo tissue development. Although multiple skeletal tissue engineering applications already exist, the underlying mechanisms at protein ... [more ▼]

The in vitro engineering of tissues may be achieved by mimicking in vivo tissue development. Although multiple skeletal tissue engineering applications already exist, the underlying mechanisms at protein level are often poorly understood. Growth factors and protein pathways precisely navigate mesenchymal stem cells trough the correct cascades. A detailed understanding of these cascades will enable us to develop efficient and robust production methods, which are required for large scale tissue engineering applications. Multiple studies hypothesize that the Wnt/β-catenin pathway acts as a switching mechanism to determine the differential fate of esenchymal cells in osteoblasts or chondrocytes during skeletogenesis. The concentration of β-catenin is a key factor in this mechanism. Wnt upregulates the productionof β-catenin which in turn upregulates Runx2 and downregulates Sox9. High concentrations of Runx2 relative to Sox9 lead to osteoblasts, while the opposite situation leads to chondrocytes. Crosstalks of the Wnt pathway with other pathways such as that of BMP and ERK expand the amount of factors that can influence β-catenin, turning the linear signaling cascade into a complex network with multiple starting conditions. A mathematical model was derived from literature describing the pathways of BMP, Wnt and ERK as well as various crosstalks between these pathways that were suggested in literature. CellDesigner™ was used to formulate, solve and visualize the Ordinary Differential Equations describing the temporal evolution of the various model constituents. Multiple starting conditions (various concentrations of BMP, Wnt and ERK) were examined to clarify the crosstalk effect. Modeling various crosstalks proposed in literature resulted in a mutual inhibitory effect between Wnt and BMP signaling, an effect independently described in literature. Experiments are ongoing to corroborate the model predictions. [less ▲]

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See detailDesign of treatment strategies for an atrophic nonunion case in fracture healing
Geris, Liesbet ULg; Vander Sloten, Jos; Van Oosterwyck, Hans

in proceedings of the IVth International Conference on Computational Bioengineering (2009)

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See detailMathematical modeling of bone regeneration during fracture healing
Geris, Liesbet ULg; Vander Sloten, Hans; Van Oosterwyck, Hans

in proceedings of the National Conference on Theoretical and Applied Mechanics (2009)

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See detailBiomaterial Surface Characteristics Modulate the Outcome of Bone Regeneration around Endosseous Oral Implants: In Silico Modeling
Amor, Nadya; Geris, Liesbet ULg; Vander Sloten, Jos et al

in Miller, Karol; Nielsen, Poul M.F. (Eds.) MICCAI 2009 Workshop Proceedings (2009)

Experimental investigations have demonstrated the importance of platelets and their activation for bone regeneration around oral implants. This study aimed to numerically demonstrate the key role of ... [more ▼]

Experimental investigations have demonstrated the importance of platelets and their activation for bone regeneration around oral implants. This study aimed to numerically demonstrate the key role of activated platelets which is controlled by implant surface characteristics. The cellular activities involved in the process of peri-implant endosseous healing can be represented by migration, proliferation, differentiation, removal, extracellular matrix synthesis and degradation, and growth factor production/release and decay. These activities are described by a system of highly coupled non-linear partial differential equations of taxis–diffusion–reaction type. Moreover, cell–biomaterial interactions were treated by including surface-specific model parameters. A well-designed in vivo model that looked at healing around oral implants with different surface properties was selected from literature to validate the results. Numerical simulations agreed well with the experimentally observed healing response and demonstrated that platelet-related model parameters, which were dependent on implant surface characteristics, modulate the pattern of healing. [less ▲]

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See detailModelling of in vitro mesenchymal stem cell cultivation, chondrogenesis and osteogenesis
Geris, Liesbet ULg; Peiffer, Véronique; Demol, Jan et al

in Journal of Biomechanics (2008, July), 41

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See detailA mathematical model of bone regeneration including angiogenesis: relevance for tissue engineering strategies
Van Oosterwyck, Hans; Vander Sloten, Jos; Geris, Liesbet ULg

in European Cells and Materials (2008), Vol. 14(Suppl. 1,), 29

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See detailAn integrated mathematical modelling framework for the study of bone fracture healing
Geris, Liesbet ULg; Vander Sloten, Jos; Van Oosterwyck, Hans

in Journal of Biomechanics (2008), 41

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See detailMathematical modelling of bone regeneration including angiogenesis: design of treatment strategies for atrophic non-unions
Geris, Liesbet ULg; Vander Sloten, Jos; Van Oosterwyck, Hans

in Proceedings of the 54th Annual Meeting of the Orthopaedic Research Society (2008)

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See detailComputational modelling of peri-implant bone healing considering cell-biomaterial interactions
Amor, Nadya; Geris, Liesbet ULg; Vander Sloten, Jos et al

in Arbor, Ann (Ed.) Proceedings of the North American Congress on Biomechanics (2008)

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See detailModelling of peri-implant osteogenesis by means of a fracture healing mode
Amor, Nadia; Geris, Liesbet ULg; Vander Sloten, Jos et al

in Journal of Biomechanics (2008), 41(S1), 289

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See detailComputational modelling of peri-implant healing
Amor, Nadia; Geris, Liesbet ULg; Vander Sloten, Jos et al

in Middleton, J.; Jones, M. L.; Shrive, N. (Eds.) Proceedings of the 8th interantional symposium on Computer Methods in Biomechanics and Biomedical Engineering (2008)

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See detailApplication of mechanoregulatory models to simulate peri-implant tissue formation in an in vivo bone chamber
Geris, Liesbet ULg; Vandamme, Katleen; Naert, Ignace et al

in Journal of Biomechanics (2008), 41(1), 145-154

Several mechanoregulatory tissue differentiation models have been proposed over the last decade. Corroboration of these models by comparison with experimental data is necessary to determine their ... [more ▼]

Several mechanoregulatory tissue differentiation models have been proposed over the last decade. Corroboration of these models by comparison with experimental data is necessary to determine their predictive power. So far, models have been applied with various success rates to different experimental set-ups investigating mainly secondary fracture heating. In this study, the mechanoregulatory models are applied to simulate the implant osseointegration process in a repeated sampling in vivo bone chamber, placed in a rabbit tibia. This bone chamber provides a mechanically isolated environment to study tissue differentiation around titanium implants loaded in a controlled manner. For the purpose of this study, bone formation around loaded cylindrical and screw-shaped implants was investigated. Histologically, no differences were found between the two implant geometries for the global amount of bone formation in the entire chamber. However, a significantly larger amount of bone-to-implant contact was observed for the screw-shaped implant compared to the cylindrical implant. In the simulations, a larger amount of bone was also predicted to be in contact with the screw-shaped implant. However, other experimental observations could not be predicted. The simulation results showed a distribution of cartilage, fibrous tissue and (im)mature bone, depending on the mechanoregulatory model that was applied. In reality, no cartilage was observed. Adaptations to the differentiation models did not lead to a better correlation between experimentally observed and numerically predicted tissue distribution patterns. The hypothesis that the existing mechanoregulatory models were able to predict the patterns of tissue formation in the in vivo bone chamber could not be fully sustained. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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