References of "Geris, Liesbet"
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See detailMULTIPHYSICS MODELING OF CELL/MATRIX GROWTH ON 3D STRUCTURES.
Guyot, Yann ULg; Papantoniou, Ioannis; Chai, Yoke Chin et al

Conference (2013, August 26)

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See detailModeling the influence of oxygen in delayed bone fracture healing.
Carlier, Aurélie ULg; Geris, Liesbet ULg; Van Oosterwyck, Hans

Conference (2013, August 25)

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See detailContrast-enhanced nanofocus X-ray computed tomography allows virtual 3D histopathology and morphometric analysis of osteoarthritis in small animal models
Kerckhofs, Greet ULg; Sainz, J.; Maréchal, M. et al

in Cartilage (2013)

Objective: One of the early hallmarks of osteoarthritis (OA) is a progressive degeneration of the articular cartilage. Early diagnosis of OA-associated cartilage alterations would be beneficial for ... [more ▼]

Objective: One of the early hallmarks of osteoarthritis (OA) is a progressive degeneration of the articular cartilage. Early diagnosis of OA-associated cartilage alterations would be beneficial for disease prevention and control, and for the development of disease-modifying treatments. However, early diagnosis is still hampered by a lack of quantifiable readouts in preclinical models. Design: In this study, we have shown the potency of contrast-enhanced nanofocus x-ray computed tomography (CE-nanoCT) to be used for virtual 3-dimensional (3D) histopathology in established mouse models for OA, and we compared with standard histopathology. Results: We showed the equivalence of CE-nanoCT images to histopathology for the modified Mankin scoring of the cartilage structure and quality. Additionally, a limited set of 3D cartilage characteristics measured by CE-nanoCT image analysis in a user-independent and semiautomatic manner, that is, average and maximum of the noncalcified cartilage thickness distribution and loss in glycosaminoglycans, was shown to be predictive for the cartilage quality and structure as can be evaluated by histopathological scoring through the use of an empirical model. Conclusions: We have shown that CE-nanoCT is a tool that allows virtual histopathology and 3D morphological quantification of multitissue systems, such as the chondro-osseous junction. It provides faster and more quantitative data on cartilage structure and quality compared with standard histopathology while eliminating user bias. CE-nanoCT thus should allow capturing subtle differences in cartilage characteristics, carefully mapping OA progression and, ultimately, asses the beneficial changes when testing a candidate disease-modifying treatment. [less ▲]

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See detailA MATHEMATICAL MODEL FOR CELL/MATRIX GROWTH ON 3D SURFACES USING THE LEVEL SET METHOD.
Guyot, Yann ULg; Papantoniou, Ioannis; Chai, Yoke Chin et al

Conference (2013, April 03)

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See detailA multiscale model of the influence of oxygen during bone fracture healing.
Carlier, Aurélie ULg; Geris, Liesbet ULg; Van Oosterwyck, Hans

Poster (2013, April 03)

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See detailComputational modeling in tissue engineering
Geris, Liesbet ULg

Book published by Springer - 1 (2013)

One of the major challenges in tissue engineering is the translation of biological knowledge on complex cell and tissue behavior into a predictive and robust engineering process. Mastering this complexity ... [more ▼]

One of the major challenges in tissue engineering is the translation of biological knowledge on complex cell and tissue behavior into a predictive and robust engineering process. Mastering this complexity is an essential step towards clinical applications of tissue engineering. This volume discusses computational modeling tools that allow studying the biological complexity in a more quantitative way. More specifically, computational tools can help in: (i) quantifying and optimizing the tissue engineering product, e.g. by adapting scaffold design to optimize micro-environmental signals or by adapting selection criteria to improve homogeneity of the selected cell population; (ii) quantifying and optimizing the tissue engineering process, e.g. by adapting bioreactor design to improve quality and quantity of the final product; and (iii) assessing the influence of the in vivo environment on the behavior of the tissue engineering product, e.g. by investigating vascular ingrowth. The book presents examples of each of the above mentioned areas of computational modeling. The underlying tissue engineering applications will vary from blood vessels over trachea to cartilage and bone. For the chapters describing examples of the first two areas, the main focus is on (the optimization of) mechanical signals, mass transport and fluid flow encountered by the cells in scaffolds and bioreactors as well as on the optimization of the cell population itself. In the chapters describing modeling contributions in the third area, the focus will shift towards the biology, the complex interactions between biology and the micro-environmental signals and the ways in which modeling might be able to assist in investigating and mastering this complexity. The chapters cover issues related to (multiscale/multiphysics) model building, training and validation, but also discuss recent advances in scientific computing techniques that are needed to implement these models as well as new tools that can be used to experimentally validate the computational results. [less ▲]

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See detailMechanobiological modeling can explain orthodontic tooth movement: three case studies.
Van Schepdael, An ULg; Vander Sloten, J.; Geris, Liesbet ULg

in Journal of Biomechanics (2013), 46(3), 470-7

Progress in medicine and higher expectation of quality of life has led to a higher demand for several dental and medical treatments. This increases the occurrence of situations in which orthodontic ... [more ▼]

Progress in medicine and higher expectation of quality of life has led to a higher demand for several dental and medical treatments. This increases the occurrence of situations in which orthodontic treatment is complicated by pathological conditions, medical therapies and drugs. Together with experiments, computer models might lead to a better understanding of the effect of pathologies and medical treatment on tooth movement. This study uses a previously presented mechanobiological model of orthodontic tooth displacement to investigate the effect of pathologies and (medical) therapies on the result of orthodontic treatment by means of three clinically relevant case studies looking at the effect of estrogen deficiency, the effect of OPG injections and the influence of fluoride intake. When less estrogen was available, the model predicted bone loss and a rise in the number of osteoclasts present at the compression side, and a faster bone resorption. These effects were also observed experimentally. Experiments disagreed on the effect of estrogen deficiency on bone formation, while the mechanobiological model predicted very little difference between the pathological and the non-pathological case at formation sites. The model predicted a decrease in tooth movement after OPG injections or fluoride intake, which was also observed in experiments. Although more experiments and model analysis is needed to quantitatively validate the mechanobiological model used in this study, its ability to conceptually describe several pathological conditions is an important measure for its validity. [less ▲]

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See detailAnalytical determination of stress patterns in the periodontal ligament during orthodontic tooth movement.
Van Schepdael, An ULg; Geris, Liesbet ULg; Vander Sloten, Jos

in Medical Engineering & Physics (2013), 35(3), 403-10

A dedicated software package that allows simulation of tooth movement can lead to shortening of the treatment program in orthodontics. A first step in the development of this software is the modelling of ... [more ▼]

A dedicated software package that allows simulation of tooth movement can lead to shortening of the treatment program in orthodontics. A first step in the development of this software is the modelling of the movement of a single tooth. Forces applied to the crown of the tooth are transmitted to the alveolar bone through the periodontal ligament, stretching, and compressing the ligament, eventually resulting in tooth movement. This paper presents an analytical model that predicts stresses and strains inside this ligament by approximating the shape of the root as an elliptic paraboloid. The model input consists of 2 material parameters and 4 geometrical parameters. To assess the accuracy of the model a finite element model (FEM) was constructed to compare the results and the influence of the eccentricity of the root was studied. The results show that the model is able to successfully describe the global behavior of the PDL and, except at a region near the alveolar crest, the differences between analytical and FEM results are small. In contrast to FEM, the analytical model does not require setting up a 3D-model and creating a mesh, allowing for significantly lower computational times and reducing cost when implementing in clinical practice. [less ▲]

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See detailMechanisms of cell migration in the adult brain: modelling subventricular neurogenesis.
Van Schepdael, An ULg; Ashbourn, J. M. A.; Beard, R. et al

in Computer Methods in Biomechanics & Biomedical Engineering (2013)

Neurogenesis has been the subject of active research in recent years. Although the majority of neurons form during the embryonic period, neurogenesis continues in restricted regions of the mammalian brain ... [more ▼]

Neurogenesis has been the subject of active research in recent years. Although the majority of neurons form during the embryonic period, neurogenesis continues in restricted regions of the mammalian brain well into adulthood. In rodent brains, neuronal migration is present in the rostral migratory stream (RMS), connecting the subventricular zone to the olfactory bulb (OB). The migration in the RMS is characterised by a lack of dispersion of neuroblasts into the surrounding tissues and a highly directed motion towards the OB. This study uses a simple mathematical model to investigate several theories of migration of neuroblasts through the RMS proposed in the literature, including chemo-attraction, chemorepulsion, general inhibition and the presence of a migration-inducing protein. Apart from the general inhibition model, all the models were able to provide results in good qualitative correspondence with the experimental observations. [less ▲]

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See detailA mechanobiological model of orthodontic tooth movement.
Van Schepdael, A; Vander Sloten, J; Geris, Liesbet ULg

in Biomechanics & Modeling in Mechanobiology (2013)

Orthodontic tooth movement is achieved by the process of repeated alveolar bone resorption on the pressure side and new bone formation on the tension side. In order to optimize orthodontic treatment, it ... [more ▼]

Orthodontic tooth movement is achieved by the process of repeated alveolar bone resorption on the pressure side and new bone formation on the tension side. In order to optimize orthodontic treatment, it is important to identify and study the biological processes involved. This article presents a mechanobiological model using partial differential equations to describe cell densities, growth factor concentrations, and matrix densities occurring during orthodontic tooth movement. We hypothesize that such a model can predict tooth movement based on the mechanobiological activity of cells in the PDL. The developed model consists of nine coupled non-linear partial differential equations, and two distinct signaling pathways were modeled: the RANKL-RANK-OPG pathway regulating the communication between osteoblasts and osteoclasts and the TGF-beta pathway mediating the differentiation of mesenchymal stem cells into osteoblasts. The predicted concentrations and densities were qualitatively validated by comparing the results to experiments reported in the literature. In the current form, the model supports our hypothesis, as it is capable of conceptually simulating important features of the biological interactions in the alveolar bone-PDL complex during orthodontic tooth movement. [less ▲]

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See detailIn vitro and in vivo comparative study of material properties crucial for reverse engineering of calcium phosphate scaffolds
Chai, Yoke Chin; Kerckhofs, Greet ULg; Bertels, Jeroen et al

Conference (2013)

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See detailContrast-enhanced nanofocus computed tomography for virtual 3D histopathology and morphometric analysis of multiple skeletal tissues
Kerckhofs, Greet ULg; Papantoniou, Ioannis; Sonnaert, Maarten et al

Conference (2013)

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See detailMicro-CT for first line screening of the scaffold material-, cell-and donor-variability on the ectopic bone forming capacity of tissue engineering constructs
Geeroms, Carla; Roberts, Scott; Van Hove, Astrid et al

Conference (2013)

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See detailOptimised contrast enhanced nanoCT for volumetric analyses of in vitro manufactured tissue-engineered bone constructs
Sonnaert, Maarten; Kerckhofs, Greet ULg; Papantoniou, Ioannis et al

Conference (2013)

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See detailContrast enhanced nanoCT for volumetric analyses of in vitro manufactured tissue-engineered bone constructs: a soft tissue case study
Sonnaert, Maarten; Papantoniou, Ioannis; Geris, Liesbet ULg et al

Conference (2013)

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See detailContrast enhanced nanoCT for 3D quantitative and spatial analysis of in vitro manufactured extracellular matrix in metallic tissue engineering scaffolds
Sonnaert, Maarten; Papantoniou, Ioannis; Geris, Liesbet ULg et al

in Abstract book User Meeting Bruker MicroCT 2013 (2013)

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See detailMicro-CT evaluation of the effect of material, donor and implantation site variability on the bone forming capacity of progenitor cell/CaP-collagen constructs implanted ectopically in nude mice
Van Hove, Astrid; Geeroms, Carla; Maréchal, Marina et al

in Abstract book User Meeting Bruker MicroCT 2013 (2013)

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See detailThree dimensional characterization of tissue-engineered constructs by contrast enhanced nanofocus computed tomography.
Papantoniou, Ioannis; Sonnaert, Maarten; Geris, Liesbet ULg et al

in Tissue engineering. Part C, Methods (2013)

In order to successfully implement tissue engineered (TE) constructs as part of a clinical therapy, it is necessary to first develop and validate quality control tools that will ensure accurate and ... [more ▼]

In order to successfully implement tissue engineered (TE) constructs as part of a clinical therapy, it is necessary to first develop and validate quality control tools that will ensure accurate and consistent TE construct release specifications. Hence advanced methods to monitor TE construct properties need to be further developed. In this study we showed proof of concept for contrast enhanced nanofocus computed tomography (CE-nanoCT) as a 'whole-construct' imaging technique with non-invasive potential that enables 3D visualization and quantification of in vitro engineered extracellular matrix (ECM) in TE constructs. In particular we performed a 3D quantitative and qualitative structural and spatial assessment of the in vitro engineered ECM, formed during static and perfusion bioreactor cell culture in 3D TE scaffolds, using two contrast agents, namely Hexabrix(R) and phosphotungstic acid (PTA). CE-nanoCT image data were validated by comparison to Live/Dead viability/cytotoxicity and picrosirius red staining data, and to the net dry weight of the TE constructs. When using Hexabrix(R) as contrast agent, ECM volume fitted linearly with net dry ECM weight independent from the flow rate used. When using PTA as contrast agent, CE-nanoCT data showed pronounced distinction between flow conditions when compared to both net dry weight and picrosirius red staining data although linearity was maintained, indicating culture-specific structural ECM differences. This was attributed to the binding specificity of this contrast agent. This novel type of information can contribute to optimize bioreactor culture conditions and potentially critical quality characteristics of TE constructs such as ECM quantity and homogeneity, facilitating the gradual transformation of 'TE constructs' in well characterized 'TE products'. [less ▲]

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