Computational segmentation of collagen fibers in bone matrix indicates bone quality in ovariectomized rat spine

Daghma, Diaa Eldin S.; Malhan, Deeksha; Simon, Paul; Stötzel, Sabine; Kern, Stefanie; Hassan, Fathi; Lips, Katrin Susanne; Heiß, Christian; Khassawna, Thaqif El

doi:10.1007/s00774-017-0844-5

Cited by 12 publications

(15 citation statements)

References 16 publications

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“…This software automatically allows extracting collagen fibers in an image and quantifies the fiber properties with descriptive statistics (such as fiber angle, length, straightness, and width). 65 …”

Section: Methodsmentioning

confidence: 99%

Early osteoimmunomodulatory effects of magnesium–calcium–zinc alloys

et al. 2021

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Today, substantial attention is given to biomaterial strategies for bone regeneration, and among them, there is a growing interest in using immunomodulatory biomaterials. The ability of a biomaterial to induce neo vascularization and macrophage polarization is a major factor in defining its success. Magnesium (Mg)-based degradable alloys have attracted significant attention for bone regeneration owing to their biodegradability and potential for avoiding secondary removal surgeries. However, there is insufficient evidence in the literature regarding the early inflammatory responses to these alloys in vivo. In this study, we investigated the early body responses to Mg-0.45wt%Zn-0.45wt%Ca pin-shaped alloy (known as ZX00 alloy) in rat femora 2, 5, and 10 days after implantation. We used 3D micro computed tomography (µCT), histological, immunohistochemical, histomorphometrical, and small angle X-ray scattering (SAXS) analyses to study new bone formation, early macrophage polarization, neo vascularization, and bone quality at the implant bone interface. The expression of macrophage type 2 biological markers increased significantly after 10 days of Mg alloy implantation, indicating its potential in stimulating macrophage polarization. Our biomineralization results using µCT as well as histological stained sections did not indicate any statistically significant differences between different time points for both groups. The activity of alkaline phosphatase (ALP) and Runt-related transcription factor 2 (Runx 2) biological markers decreased significantly for Mg group, indicating less osteoblast activity. Generally, our results supported the potential of ZX00 alloy to enhance the expression of macrophage polarization in vivo; however, we could not observe any statistically significant changes regarding biomineralization.

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Section: Methodsmentioning

confidence: 99%

Early osteoimmunomodulatory effects of magnesium–calcium–zinc alloys

et al. 2021

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“…FibrilTool quantifies collagen fibrils in a region of interest (ROI) of a high-resolution TEM (HRTEM) image using ImageJ software (ImageJ version 2.4, National Institutes of Health, Bethesda, MD, USA). The concept of nematic tensor approach from liquid crystals is used to quantify the main orientation of fibrillary structures in the analysed image [38,39]. The output is a statement about how the fibrils are aligned and are computed on the basis of pixel intensity level in the selected ROIs.…”

Section: Quantification Of Collagen Fibrils Using Fibriltoolmentioning

confidence: 99%

Investigation of strontium transport and strontium quantification in cortical rat bone by time-of-flight secondary ion mass spectrometry

Kern

Quade

Ray

et al. 2019

J. R. Soc. Interface.

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Next-generation bone implants will be functionalized with drugs for stimulating bone growth. Modelling of drug release by such functionalized biomaterials and drug dispersion into bone can be used as predicting tool for biomaterials testing in future. Therefore, the determination of experimental parameters to describe and simulate drug release in bone is essential. Here, we focus on Sr 2+ transport and quantification in cortical rat bone. Sr 2+ dose-dependently stimulates bone-building osteoblasts and inhibits bone-resorbing osteoclasts. It should be preferentially applied in the case of bone fracture in the context of osteoporotic bone status. Transport properties of cortical rat bone were investigated by dipping experiments of bone sections in aqueous Sr 2+ solution followed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiling. Data evaluation was carried out by fitting a suitable mathematical diffusion equation to the experimental data. An average diffusion coefficient of D = (1.68 ± 0.57) · 10 −13 cm 2 s −1 for healthy cortical bone was obtained. This value differed only slightly from the value of D = (4.30 ± 1.43) · 10 −13 cm 2 s −1 for osteoporotic cortical bone. Transmission electron microscopy investigations revealed a comparable nano- and ultrastructure for both types of bone status. Additionally, Sr 2+ -enriched mineralized collagen standards were prepared for ToF-SIMS quantification of Sr 2+ content. The obtained calibration curve was used for Sr 2+ quantification in cortical and trabecular bone in real bone sections. The results allow important insights regarding the Sr 2+ transport properties in healthy and osteoporotic bone and can ultimately be used to perform a simulation of drug release and mobility in bone.

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“…Additionally, the Von Kossa/Van Gieson staining of histological sections and subsequent calculation of the relative osteoid area (O.Ar/B.Ar) demonstrated an unaffected osteoid formation by osteoblasts after immunization. However, alterations regarding collagen fiber arrangement, regulation of mRNA and protein level, as well as collagen products in blood serum, are common findings in animal models of osteoporosis and human osteoporosis patients [21][22][23]. The differences between the decreased mineralization activity in contrast to the remaining collagen and osteoid synthesis may suggest a differentiated regulation of osteoblast activity and specific enzymes in the case of EAO and immunization with adjuvants alone, different from other animal models and human osteoporosis in the elderly.…”

Section: Discussionmentioning

confidence: 96%

Bone Status in a Mouse Model of Experimental Autoimmune-Orchitis

Hemm

Fijak

Belikan

et al. 2021

IJMS

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Investigations in male patients with fertility disorders revealed a greater risk of osteoporosis. The rodent model of experimental autoimmune-orchitis (EAO) was established to analyze the underlying mechanisms of male infertility and causes of reduced testosterone concentration. Hence, we investigated the impact of testicular dysfunction in EAO on bone status. Male mice were immunized with testicular homogenate in adjuvant to induce EAO (n = 5). Age-matched mice were treated with adjuvant alone (adjuvant, n = 6) or remained untreated (control, n = 7). Fifty days after the first immunization specimens were harvested. Real-time reverse transcription-PCR indicated decreased bone metabolism by alkaline phosphatase and Cathepsin K as well as remodeling of cell-contacts by Connexin-43. Micro computed tomography demonstrated a loss of bone mass and mineralization. These findings were supported by histomorphometric results. Additionally, biomechanical properties of femora in a three-point bending test were significantly altered. In summary, the present study illustrates the induction of osteoporosis in the investigated mouse model. However, results suggest that the major effects on bone status were mainly caused by the complete Freund’s adjuvant rather than the autoimmune-orchitis itself. Therefore, the benefit of the EAO model to transfer laboratory findings regarding bone metabolism in context with orchitis into a clinical application is limited.

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Computational segmentation of collagen fibers in bone matrix indicates bone quality in ovariectomized rat spine

Cited by 12 publications

References 16 publications

Early osteoimmunomodulatory effects of magnesium–calcium–zinc alloys

Early osteoimmunomodulatory effects of magnesium–calcium–zinc alloys

Investigation of strontium transport and strontium quantification in cortical rat bone by time-of-flight secondary ion mass spectrometry

Bone Status in a Mouse Model of Experimental Autoimmune-Orchitis

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