Ptychographic X-ray CT characterization of the osteocyte lacuno-canalicular network in a male rat's glucocorticoid induced osteoporosis model

Ciani, Antonia; Toumi, Hechmi; Pallu, Stéphane; Tsai, Esther H. R.; Díaz, Ana; Guizar‐Sicairos, Manuel; Holler, Mirko; Lespessailles, Éric; Kewish, Cameron M.

doi:10.1016/j.bonr.2018.07.005

Cited by 24 publications

(25 citation statements)

References 66 publications

(107 reference statements)

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“…This work reports quantitative parameters of the LCN from X-ray phase nano-CT images at two voxel sizes and assesses the effect of the spatial resolution by comparing results obtained from registered images. A voxel size of 30 nm is the highest spatial resolution that has ever been reported for the analysis of human bone samples by using this technique, even if similar spatial resolution can be reached for instance from ptychography 28 or FIB/ SEM techniques 23 . Nevertheless, the effect of the improved spatial resolution in terms of the quantitative assessment of the LCN needed to be clarified.…”

Section: Discussionmentioning

confidence: 93%

“…The first report of the number of primary canaliculi was an estimation derived from a model and using values of the literature 50 , thus not from direct observations. More recently measurements were reported in rats using confocal microscopy 51 and ptychography 28 . The ratio between the number of canaliculi per lacuna and the surface area of lacuna (Ca.N/Lc.S) describing a local density of canaliculi increases progressively from 0.21 µm −2 at 1.2 µm to 0.32 µm −2 at 12.0 µm (30 nm voxel size), while on the PCM volumes it fluctuates around 0.16 µm −2 (see Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Besides, it is possible to image the 3D structure of the LCN with Synchrotron Radiation nano-CT (SR nCT) providing an isotropic spatial resolution and a relatively large field of view 25,26 . The feasibility of ptychographic X-ray CT with synchrotron radiation was also demonstrated 27 and recently used to visualize the LCN in rats 28 . While providing excellent spatial resolution, acquisition time is lengthy and the specimen dimensions have to fit within a reduced field of view.…”

mentioning

confidence: 96%

“…The first parameter of interest is the canalicular porosity volume, which was reported for instance in rodents 23 , and more rarely in human 33 . The diameter of canaliculi has also been reported from SR nCT images 33,34 , or ptychographic images 28 , as well as the number of canaliculi per lacuna 34,35 . While in the majority of studies the lacunae and canaliculi have been evaluated separately, a recent study used the theory of complex network to assess the LCN in ovine and murine bone 36 .…”

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confidence: 99%

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Assessment of the human bone lacuno-canalicular network at the nanoscale and impact of spatial resolution

Pacureanu

Olivier

et al. 2020

Sci Rep

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cécile olivier 1,2 , peter cloetens 2 & françoise peyrin 1,2* Recently, increasing attention has been given to the study of osteocytes, the cells that are thought to play an important role in bone remodeling and in the mechanisms of bone fragility. the interconnected osteocyte system is deeply embedded inside the mineralized bone matrix and lies within a closely fitted porosity known as the lacuno-canalicular network. However, quantitative data on human samples remain scarce, mostly measured in 2D, and there are gaps to be filled in terms of spatial resolution. In this work, we present data on femoral samples from female donors imaged with isotropic 3D spatial resolution by magnified X-ray phase nano computerized-tomography. We report quantitative results on the 3D structure of canaliculi in human femoral bone imaged with a voxel size of 30 nm. We found that the lacuno-canalicular porosity occupies on average 1.45% of the total tissue volume, the ratio of the canalicular versus lacunar porosity is about 37.7%, and the primary number of canaliculi stemming from each lacuna is 79 on average. The examination of this number at different distances from the surface of the lacunae demonstrates branching in the canaliculi network. We analyzed the impact of spatial resolution on quantification by comparing parameters extracted from the same samples imaged with 120 nm and 30 nm voxel sizes. To avoid any bias related to the analysis region, the volumes at 120 nm and 30 nm were registered and cropped to the same field of view. Our results show that the measurements at 120 and 30 nm are strongly correlated in our data set but that the highest spatial resolution provides more accurate information on the canaliculi network and its branching properties.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 96%

mentioning

confidence: 99%

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Assessment of the human bone lacuno-canalicular network at the nanoscale and impact of spatial resolution

Pacureanu

Olivier

et al. 2020

Sci Rep

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“…With implication of PLR in both physiological and pathological conditions, including renal osteodystrophy, glucocorticoid-induced osteonecrosis, osteoarthritis, and hyperparathyroidism (21,(66)(67)(68)(69)(70)(71) , defining the sex differences in these cell-intrinsic cues and molecular networks in osteocytes will be critical to address sexual dimorphism in the prevalence and manifestation of bone fragility, as well as refining therapeutics for reducing fracture risk.…”

Section: Discussionmentioning

confidence: 99%

TGFβ regulation of perilacunar/canalicular remodeling is sexually dimorphic

Dole

Yee

Mazur

et al. 2019

Preprint

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1.AbstractBone fragility is the product of defects in bone mass and bone quality, both of which show sex-specific differences. Despite this, the cellular and molecular mechanisms underpinning the sexually dimorphic control of bone quality remain unclear, limiting our ability to effectively prevent fractures, especially in postmenopausal osteoporosis. Recently, using male mice, we found that systemic or osteocyte-intrinsic inhibition of TGFβ signaling, achieved using the 9.6-kb DMP1 promoter-driven Cre recombinase (TβRIIocy−/− mice), suppresses osteocyte perilacunar/canalicular remodeling (PLR) and compromises bone quality. Since systemic TGFβ inhibition more robustly increases bone mass in female than male mice, we postulated that sex-specific differences in bone quality could likewise result, in part, from dimorphic regulation of PLR by TGFβ. Moreover, since lactation induces PLR, we examined the effect of TGFβ inhibition on the female skeleton during lactation. In contrast to males, female mice that possess an osteocyte-intrinsic defect in TGFβ signaling were protected from TGFβ-dependent defects in PLR and bone quality. The expression of requisite PLR enzymes, the lacuno-canalicular network, and the flexural strength of female TβRIIocy−/− bone was intact. With lactation, however, bone loss, and induction in PLR and osteocytic parathyroid hormone type I receptor (PTHR1) expression, were suppressed in TβRIIocy−/− bone, relative to wild-type. Indeed, differential control of PTHR1 expression, by TGFβ and other factors, may contribute to dimorphism in PLR regulation in male and female TβRIIocy−/− mice. These findings provide key insights into the sex-based differences in osteocyte PLR that underlie bone quality and highlight TGFβ signaling as a crucial regulator of lactation-induced PLR.

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Utilizing Synchrotron Radiation for the Characterization of Biodegradable Magnesium Alloys—From Alloy Development to the Application as Implant Material

et al. 2021

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Magnesium (Mg)-based alloys are investigated for the use as lightweight structural metals, e.g., in the automotive industry, [1] as biodegradable implant materials [2] and for hydrogen storage. [3] The choice of alloying system and subsequent processing of the material is a crucial factor for the degradation profile of the alloy and its mechanical properties. [4][5][6][7] This review focuses on use of Mg alloys as implant material, with some references to its application as a structural metal.The degradation profile of Mg alloys is of particular importance for their application as implant materials, as a controlled degradation is required to ensure cell viability and implant stability in vivo. [8,9] During the development of Mg alloys for the application as a biodegradable implant, alloying systems are carefully selected and manufactured, with their microstructure being tailored according to specifications by selecting the appropriate processing route. The microstructure and the mechanical properties of the alloy will be evaluated and the alloy is then tested for in vitro degradation in an aqueous environment under physiological conditions (pH %7.4, 37 C, 5% CO 2 , 21% O 2 , 95% rel. humidity) with and without cells to assess its general degradation properties and cell viability. [10] The mechanical properties and degradation profile need to be tailored depending on the application of the implant. Mg alloys for bone support, for example, require mechanical properties close to that of bone. For bone, the average Young's modulus is between 7 and 31 GPa, depending on the type of bone and its hydration state. [11,12] In longitudinal direction, the bone's tensile and compressive ultimate strength have been reported to be between 93 and 135 MPa, and 154 and 205 MPa, respectively. [13,14] Finally, the elongation to failure of the clinically approved MAGNEZIX screw by Syntellix AG (Hanover, Germany) was determined to be 8%. [15] By contrast, Mg alloys designed for the use as stents must possess a minimum ultimate tensile strength of 300 MPa, low yield strength of 200-300 MPa, and higher ductility (min. 15%-18% elongation to failure, preferably 30%) for their successful deployment. [16,17] Finally, in vivo animal experiments are conducted to evaluate the alloy suitability for the translation into the clinic.

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Ptychographic X-ray CT characterization of the osteocyte lacuno-canalicular network in a male rat's glucocorticoid induced osteoporosis model

Cited by 24 publications

References 66 publications

Assessment of the human bone lacuno-canalicular network at the nanoscale and impact of spatial resolution

Assessment of the human bone lacuno-canalicular network at the nanoscale and impact of spatial resolution

TGFβ regulation of perilacunar/canalicular remodeling is sexually dimorphic

Utilizing Synchrotron Radiation for the Characterization of Biodegradable Magnesium Alloys—From Alloy Development to the Application as Implant Material

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