The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Françoise Peyrin - One of the best experts on this subject based on the ideXlab platform.
-
3D osteocyte Lacunar morphometric properties and distributions in human femoral cortical bone using synchrotron radiation micro-CT images
BONE, 2015Co-Authors: P. Dong, P.-J. Gouttenoire, Sylvain Haupert, Valérie Bousson, B. Hesse, M Langer, Françoise PeyrinAbstract:Osteocytes, the most numerous bone cells, are thought to be actively involved in the bone modeling and remodeling processes. The morphology of osteocyte is hypothesized to adapt according to the physiological mechanical loading. Three-dimensional micro-CT has recently been used to study osteocyte Lacunae. In this work, we proposed a computationally efficient and validated automated image analysis method to quantify the 3D shape descriptors of osteocyte Lacunae and their distribution in human femurs. Thirteen samples were imaged using Synchrotron Radiation (SR) micro-CT at ID19 of the ESRF with 1.4μm isotropic voxel resolution. With a field of view of about 2.9×2.9×1.4mm3, the 3D images include several tens of thousands of osteocyte Lacunae. We designed an automated quantification method to segment and extract 3D cell descriptors from osteocyte Lacunae. An image moment-based approach was used to calculate the volume, length, width, height and anisotropy of each osteocyte Lacuna. We employed a fast algorithm to further efficiently calculate the surface area, the Euler number and the structure model index (SMI) of each Lacuna. We also introduced the 3D Lacunar density map to directly visualize the Lacunar density variation over a large field of view. We reported the Lacunar morphometric properties and distributions as well as cortical bone histomorphometric indices on the 13 bone samples. The mean volume and surface were found to be 409.5±149.7μm3 and 336.2±94.5μm2. The average dimensions were of 18.9±4.9μm in length, 9.2±2.1μm in width and 4.8±1.1μm in depth. We found Lacunar number density and six osteocyte Lacunar descriptors, three axis lengths, two anisotropy ratios and SMI, that are significantly correlated to bone porosity at a same local region. The proposed method allowed an automatic and efficient direct 3D analysis of a large population of bone cells and is expected to provide reliable biological information for better understanding the bone quality and diseases at cellular level.
-
Voronoi-based analysis of bone cell network from synchrotron radiation micro-CT images
2015Co-Authors: P. Dong, Sébastien Valette, M. A. Zuluaga, J. Kazakia G., Françoise PeyrinAbstract:With the development of the novel micro and nano-CT systems, bone cell analysis has gone beyond the limitation of the conventional 2D analysis. In particular synchrotron radiation micro-CT is well suited to image in 3D the lacuno-canalicular network (LCN) in bone tissue. This network is made of osteocyte Lacunae connected by small channels called canaliculi. Due to the lack of quantitative data on this network, we propose here an automated method to extract geodesic Voronoi-based parameters to characterize the regions of influence of canaliculi. To this aim, after labeling each Lacuna from the segmented LCN image, we generated geodesic Voronoi tessellations on each Lacunar surface. Our proposed method was successfully applied to three SR micro-CT images of women tibial cortical samples. We believe that this method can serve to extract new information on the 3D morphometry of the LCN in more datasets.
-
Bone canalicular network segmentation in 3D nano-CT images through geodesic voting and image tessellation.
Phys Med Biol, 2014Co-Authors: Françoise PeyrinAbstract:Recent studies emphasized the role of the bone lacuno-canalicular network (LCN) in the understanding of bone diseases such as osteoporosis. However, suitable methods to investigate this structure are lacking. The aim of this paper is to introduce a methodology to segment the LCN from three-dimensional (3D) synchrotron radiation nano-CT images. Segmentation of such structures is challenging due to several factors such as limited contrast and signal-to-noise ratio, partial volume effects and huge number of data that needs to be processed, which restrains user interaction. We use an approach based on minimum-cost paths and geodesic voting, for which we propose a fully automatic initialization scheme based on a tessellation of the image domain. The centroids of pre-segmented lacunæ are used as Voronoi-tessellation seeds and as start-points of a fast-marching front propagation, whereas the end-points are distributed in the vicinity of each Voronoi-region boundary. This initialization scheme was devised to cope with complex biological structures involving cells interconnected by multiple thread-like, branching processes, while the seminal geodesic-voting method only copes with tree-like structures. Our method has been assessed quantitatively on phantom data and qualitatively on real datasets, demonstrating its feasibility. To the best of our knowledge, presented 3D renderings of lacunæ interconnected by their canaliculi were achieved for the first time.
-
A New Quantitative Approach for Estimating Bone Cell Connections from Nano-CT Images
2013Co-Authors: P. Dong, Cecile Olivier, M. A. Zuluaga, A. Pacureanu, F. Frouin, G. Quentin, Françoise PeyrinAbstract:Recent works highlighted the crucial role of the osteocyte system in bone fragility. The number of canaliculi of osteocyte Lacuna (Lc.NCa) is an important parameter that reflects the functionality of bone tissue, but rarely reported due to the limitations of current microscopy techniques, and only assessed from 2D histology sections. Previously, we showed the Synchrotron Radiation nanotomography (SR-nanoCT) is a promising technique to image the 3D Lacunar-canalicular network. Here we present, for the first time, an automatic method to quantify the connectivity of bone cells in 3D. After segmentation, our method first separates and labels each Lacuna in the network. Then, by creating a bounding surface around Lacuna, the Lc.NCa is calculated through estimating 3D topological parameters. The proposed method was successfully applied to a 3D SR-nanoCT image of cortical femoral bone. Statistical results on 165 Lacunae are reported, showing a mean of 51, which is consistent with the literature.
Björn Busse - One of the best experts on this subject based on the ideXlab platform.
-
Inter-site Variability of the Human Osteocyte Lacunar Network: Implications for Bone Quality
Current Osteoporosis Reports, 2019Co-Authors: Petar Milovanovic, Björn BusseAbstract:Purpose of Review This article provides a review on the variability of the osteocyte Lacunar network in the human skeleton. It highlights characteristics of the osteocyte Lacunar network in relation to different skeletal sites and fracture susceptibility. Recent Findings Application of 2D analyses (quantitative backscattered electron microscopy, histology, confocal laser scanning microscopy) and 3D reconstructions (microcomputed tomography and synchrotron radiation microcomputed tomography) provides extended high-resolution information on osteocyte Lacunar properties in individuals of various age (fetal, children’s growth, elderly), sex, and disease states with increased fracture risk. Summary Recent findings on the distribution of osteocytes in the human skeleton are reviewed. Quantitative data highlighting the variability of the osteocyte Lacunar network is presented with special emphasis on site specificity and maintenance of bone health. The causes and consequences of heterogeneous distribution of osteocyte Lacunae both within specific regions of interest and on the skeletal level are reviewed and linked to differential bone quality factors and fracture susceptibility.
-
Early bone tissue aging in human auditory ossicles is accompanied by excessive hypermineralization, osteocyte death and micropetrosis
Scientific Reports, 2018Co-Authors: Tim Rolvien, Petar Milovanovic, Felix N. Schmidt, Katharina Jähn, Christoph Riedel, Sebastian Butscheidt, Klaus Püschel, Anke Jeschke, Michael Amling, Björn BusseAbstract:Within the mineralized bone, osteocytes form a multifunctional mechanosensitive network orchestrating bone remodelling. A preserved osteocyte population is a crucial determinant of bone quality. In human auditory ossicles, the early decrease in osteocyte numbers but maintained integrity remains an unexplained phenomenon that might serve for sound transmission from air to the labyrinth. Here we analysed the frequency, size and composition of osteocyte Lacunae in the auditory ossicles of 22 individuals from early postnatal period to old age. Mineralization of the bone matrix was determined using backscattered electron imaging. No signs of bone remodelling were observed above the age of 1 year. We detected characteristics of early bone tissue aging, such as decrease in osteocytes, lower total Lacunar density and Lacunar area, as well as high matrix mineralization accompanied by distinct accumulation of micropetrotic Lacunae and decreased indentation depths. The majority of these changes took place in the first months and years of life, while afterwards only minor reorganization was present. With osteocyte apoptosis potentially being a consequence of low mechanical stimuli, the early loss of osteocytes without initiation of bone remodelling indicates an adaptive response conserving the architecture of the auditory ossicles and ensuring stable sound transmission throughout life.
P. Dong - One of the best experts on this subject based on the ideXlab platform.
-
3D osteocyte Lacunar morphometric properties and distributions in human femoral cortical bone using synchrotron radiation micro-CT images
BONE, 2015Co-Authors: P. Dong, P.-J. Gouttenoire, Sylvain Haupert, Valérie Bousson, B. Hesse, M Langer, Françoise PeyrinAbstract:Osteocytes, the most numerous bone cells, are thought to be actively involved in the bone modeling and remodeling processes. The morphology of osteocyte is hypothesized to adapt according to the physiological mechanical loading. Three-dimensional micro-CT has recently been used to study osteocyte Lacunae. In this work, we proposed a computationally efficient and validated automated image analysis method to quantify the 3D shape descriptors of osteocyte Lacunae and their distribution in human femurs. Thirteen samples were imaged using Synchrotron Radiation (SR) micro-CT at ID19 of the ESRF with 1.4μm isotropic voxel resolution. With a field of view of about 2.9×2.9×1.4mm3, the 3D images include several tens of thousands of osteocyte Lacunae. We designed an automated quantification method to segment and extract 3D cell descriptors from osteocyte Lacunae. An image moment-based approach was used to calculate the volume, length, width, height and anisotropy of each osteocyte Lacuna. We employed a fast algorithm to further efficiently calculate the surface area, the Euler number and the structure model index (SMI) of each Lacuna. We also introduced the 3D Lacunar density map to directly visualize the Lacunar density variation over a large field of view. We reported the Lacunar morphometric properties and distributions as well as cortical bone histomorphometric indices on the 13 bone samples. The mean volume and surface were found to be 409.5±149.7μm3 and 336.2±94.5μm2. The average dimensions were of 18.9±4.9μm in length, 9.2±2.1μm in width and 4.8±1.1μm in depth. We found Lacunar number density and six osteocyte Lacunar descriptors, three axis lengths, two anisotropy ratios and SMI, that are significantly correlated to bone porosity at a same local region. The proposed method allowed an automatic and efficient direct 3D analysis of a large population of bone cells and is expected to provide reliable biological information for better understanding the bone quality and diseases at cellular level.
-
Voronoi-based analysis of bone cell network from synchrotron radiation micro-CT images
2015Co-Authors: P. Dong, Sébastien Valette, M. A. Zuluaga, J. Kazakia G., Françoise PeyrinAbstract:With the development of the novel micro and nano-CT systems, bone cell analysis has gone beyond the limitation of the conventional 2D analysis. In particular synchrotron radiation micro-CT is well suited to image in 3D the lacuno-canalicular network (LCN) in bone tissue. This network is made of osteocyte Lacunae connected by small channels called canaliculi. Due to the lack of quantitative data on this network, we propose here an automated method to extract geodesic Voronoi-based parameters to characterize the regions of influence of canaliculi. To this aim, after labeling each Lacuna from the segmented LCN image, we generated geodesic Voronoi tessellations on each Lacunar surface. Our proposed method was successfully applied to three SR micro-CT images of women tibial cortical samples. We believe that this method can serve to extract new information on the 3D morphometry of the LCN in more datasets.
-
A New Quantitative Approach for Estimating Bone Cell Connections from Nano-CT Images
2013Co-Authors: P. Dong, Cecile Olivier, M. A. Zuluaga, A. Pacureanu, F. Frouin, G. Quentin, Françoise PeyrinAbstract:Recent works highlighted the crucial role of the osteocyte system in bone fragility. The number of canaliculi of osteocyte Lacuna (Lc.NCa) is an important parameter that reflects the functionality of bone tissue, but rarely reported due to the limitations of current microscopy techniques, and only assessed from 2D histology sections. Previously, we showed the Synchrotron Radiation nanotomography (SR-nanoCT) is a promising technique to image the 3D Lacunar-canalicular network. Here we present, for the first time, an automatic method to quantify the connectivity of bone cells in 3D. After segmentation, our method first separates and labels each Lacuna in the network. Then, by creating a bounding surface around Lacuna, the Lc.NCa is calculated through estimating 3D topological parameters. The proposed method was successfully applied to a 3D SR-nanoCT image of cortical femoral bone. Statistical results on 165 Lacunae are reported, showing a mean of 51, which is consistent with the literature.
Haniyeh Hemmatian - One of the best experts on this subject based on the ideXlab platform.
-
mechanical loading differentially affects osteocytes in fibulae from lactating mice compared to osteocytes in virgin mice possible role for Lacuna size
Calcified Tissue International, 2018Co-Authors: Haniyeh Hemmatian, Rozita Jalali, C M Semeins, Jolanda M A Hogervorst, Harry G Van Lenthe, Jenneke Kleinnulend, Astrid D BakkerAbstract:Hormonal changes during lactation are associated with profound changes in bone cell biology, such as osteocytic osteolysis, resulting in larger Lacunae. Larger Lacuna shape theoretically enhances the transmission of mechanical signals to osteocytes. We aimed to provide experimental evidence supporting this theory by comparing the mechanoresponse of osteocytes in the bone of lactating mice, which have enlarged Lacunae due to osteocytic osteolysis, with the response of osteocytes in bone from age-matched virgin mice. The osteocyte mechanoresponse was measured in excised fibulae that were cultured in hormone-free medium for 24 h and cyclically loaded for 10 min (sinusoidal compressive load, 3000 µe, 5 Hz) by quantifying loading-related changes in Sost mRNA expression (qPCR) and sclerostin and β-catenin protein expression (immunohistochemistry). Loading decreased Sost expression by ~ threefold in fibulae of lactating mice. The loading-induced decrease in sclerostin protein expression by osteocytes was larger in lactating mice (55% decrease ± 14 (± SD), n = 8) than virgin mice (33% decrease ± 15, n = 7). Mechanical loading upregulated β-catenin expression in osteocytes in lactating mice by 3.5-fold (± 0.2, n = 6) which is significantly (p < 0.01) higher than the 1.6-fold increase in β-catenin expression by osteocytes in fibulae from virgin mice (± 0.12, n = 4). These results suggest that osteocytes in fibulae from lactating mice with large Lacunae may respond stronger to mechanical loading than those from virgin mice. This could indicate that osteocytes residing in larger Lacuna show a stronger response to mechanical loading.
-
Aging, Osteocytes, and Mechanotransduction
Current Osteoporosis Reports, 2017Co-Authors: Haniyeh Hemmatian, Astrid D Bakker, Jenneke Klein-nulend, G. Harry Van LentheAbstract:Purpose of Review The bone is able to adapt its structure to mechanical signals via the bone remodeling process governed by mechanosensitive osteocytes. With aging, an imbalance in bone remodeling results in osteoporosis. In this review, we hypothesized that changes in Lacunar morphology underlie the decreased bone mechanoresponsiveness to mechanical loading with aging. Recent Findings Several studies have reported considerable variations in the shape of osteocytes and their Lacunae with aging. Since osteocytes can sense matrix strain directly via their cell bodies, the variations in osteocyte morphology may cause changes in osteocyte mechanosensitivity. As a consequence, the load-adaptive response of osteocytes may change with aging, even when mechanical loading would remain unchanged. Summary Though extensive quantitative data is lacking, evidence exists that the osteocyte Lacunae are becoming smaller and more spherical with aging. Future dedicated studies might reveal whether these changes would affect osteocyte mechanosensation and the subsequent biological response, and whether this is (one of) the pathways involved in age-related bone loss.
Astrid D Bakker - One of the best experts on this subject based on the ideXlab platform.
-
mechanical loading differentially affects osteocytes in fibulae from lactating mice compared to osteocytes in virgin mice possible role for Lacuna size
Calcified Tissue International, 2018Co-Authors: Haniyeh Hemmatian, Rozita Jalali, C M Semeins, Jolanda M A Hogervorst, Harry G Van Lenthe, Jenneke Kleinnulend, Astrid D BakkerAbstract:Hormonal changes during lactation are associated with profound changes in bone cell biology, such as osteocytic osteolysis, resulting in larger Lacunae. Larger Lacuna shape theoretically enhances the transmission of mechanical signals to osteocytes. We aimed to provide experimental evidence supporting this theory by comparing the mechanoresponse of osteocytes in the bone of lactating mice, which have enlarged Lacunae due to osteocytic osteolysis, with the response of osteocytes in bone from age-matched virgin mice. The osteocyte mechanoresponse was measured in excised fibulae that were cultured in hormone-free medium for 24 h and cyclically loaded for 10 min (sinusoidal compressive load, 3000 µe, 5 Hz) by quantifying loading-related changes in Sost mRNA expression (qPCR) and sclerostin and β-catenin protein expression (immunohistochemistry). Loading decreased Sost expression by ~ threefold in fibulae of lactating mice. The loading-induced decrease in sclerostin protein expression by osteocytes was larger in lactating mice (55% decrease ± 14 (± SD), n = 8) than virgin mice (33% decrease ± 15, n = 7). Mechanical loading upregulated β-catenin expression in osteocytes in lactating mice by 3.5-fold (± 0.2, n = 6) which is significantly (p < 0.01) higher than the 1.6-fold increase in β-catenin expression by osteocytes in fibulae from virgin mice (± 0.12, n = 4). These results suggest that osteocytes in fibulae from lactating mice with large Lacunae may respond stronger to mechanical loading than those from virgin mice. This could indicate that osteocytes residing in larger Lacuna show a stronger response to mechanical loading.
-
Aging, Osteocytes, and Mechanotransduction
Current Osteoporosis Reports, 2017Co-Authors: Haniyeh Hemmatian, Astrid D Bakker, Jenneke Klein-nulend, G. Harry Van LentheAbstract:Purpose of Review The bone is able to adapt its structure to mechanical signals via the bone remodeling process governed by mechanosensitive osteocytes. With aging, an imbalance in bone remodeling results in osteoporosis. In this review, we hypothesized that changes in Lacunar morphology underlie the decreased bone mechanoresponsiveness to mechanical loading with aging. Recent Findings Several studies have reported considerable variations in the shape of osteocytes and their Lacunae with aging. Since osteocytes can sense matrix strain directly via their cell bodies, the variations in osteocyte morphology may cause changes in osteocyte mechanosensitivity. As a consequence, the load-adaptive response of osteocytes may change with aging, even when mechanical loading would remain unchanged. Summary Though extensive quantitative data is lacking, evidence exists that the osteocyte Lacunae are becoming smaller and more spherical with aging. Future dedicated studies might reveal whether these changes would affect osteocyte mechanosensation and the subsequent biological response, and whether this is (one of) the pathways involved in age-related bone loss.
