Magdalena Wojtków

Purpose: Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat pain, but they have side effects, including the inhibition of bone healing. Diclofenac (DF), a member of the NSAID group, affects bone health adversely. One potential approach to protect bones from the effects of NSAIDs involves the administration of short nucleic acids, such as microRNAs (miRNAs). This study aimed to determine whether two specific miRNAs, miR-15b and miR-365, could mitigate the effects of DF on bone.Methods: We used the C57BL/6J mouse strain and the MC3T3-E1 pre-osteoblast cell line derived from this mouse strain. Female C57BL/6J mice were treated with DF and miR-15b or miR-365 mimics. After euthanising the mice, we analysed their femurs using micro-computed tomography (μCT) and dynamic mechanical analysis (DMA). In addition, we performed experiments in cultured MC3T3-E1 cells, which were transfected with either miR-15b or miR-365. We assessed the relative mRNA levels of osteoblast differentiation markers using real-time PCR.Results: Our findings indicated that miR-15b and miR-365 were effective in reversing the detrimental effects of DF on bone mineral density. DF decreased the bone’s storage modulus (E’), while miR-15b and miR-365 ameliorated this effect. In the preosteoblast MC3T3-E1 cells, DF did not significantly regulate marker genes; however, the administration of miR-15b and miR-365 reduced the gene expression of Runx2, Alp, and Satb2.Conclusions: In summary, the impact of DF on the structural and mechanical properties of bone was not mediated by gene regulation in osteoblasts. However, osteoblasts were responsive to the administration of miR-15b and miR-365.

In this research, we synthesize and characterize poly(glycerol sebacate) pre-polymer (pPGS) (¹H NMR, FTiR, GPC, and TGA). Nano-hydroxyapatite (HAp) is synthesized using the wet precipitation method. Next, the materials are used to prepare a PGS-based composite with a 25 wt.% addition of HAp. Microporous composites are formed by means of thermally induced phase separation (TIPS) followed by thermal cross-linking (TCL) and salt leaching (SL). The manufactured microporous materials (PGS and PGS/HAp) are then subjected to imaging by means of SEM and µCT for the porous structure characterization. DSC, TGA, and water contact angle measurements are used for further evaluation of the materials. To assess the cytocompatibility and biological potential of PGS-based composites, preosteoblasts and differentiated hFOB 1.19 osteoblasts are employed as in vitro models. Apart from the cytocompatibility, the scaffolds supported cell adhesion and were readily populated by the hFOB1.19 preosteoblasts. HAp-facilitated scaffolds displayed osteoconductive properties, supporting the terminal differentiation of osteoblasts as indicated by the production of alkaline phosphatase, osteocalcin and osteopontin. Notably, the PGS/HAp scaffolds induced the production of significant amounts of osteoclastogenic cytokines: IL-1β, IL-6 and TNF-α, which induced scaffold remodeling and promoted the reconstruction of bone tissue. Initial biocompatibility tests showed no signs of adverse effects of PGS-based scaffolds toward adult BALB/c mice.

Despite the dynamic development of additive manufacturing technologies, including selective laser sintering (SLS), there is still limited information on the impact of key factors in printing strategy, on the properties of three-dimensional (3D) printed parts. Such factors, such as the orientation of printed layers toward the powder bed or elements target dimensions, seem to be particularly important, from both a mechanical and a structural point of view. Besides, the scientific articles mainly focus on the analysis of one type of loading condition in the samples, that is, the uniaxial tensile test, which were printed on industrial SLS printers. This is a considerable limitation because very often not only tensile forces but also compressive forces act on the structural elements. Therefore, this study aimed at evaluating the influence of desktop SLS printed parts' orientation and diameter on their structural and mechanical parameters. The mechanical properties of samples printed from PA12 powder on the desktop SLS 3D printer were tested in uniaxial tensile and compression tests, as well as structural properties were investigated. For the purposes of this article, 5 angular orientations of the samples in relation to the powder bed and three diameters of cylindrical samples were analyzed. The research has shown that in the case of samples subjected to tensile load, the printing strategy is important, and the best mechanical parameters are obtained for parts printed at an angle of 0°, that is, in the powder bed's plane. The highest values of mechanical parameters were obtained for a part oriented at an angle of 0°. In the case of the uniaxial compression test and structural parameters, the parts orientation turned out to be an insignificant factor affecting the tested parameters. However, the diameter of printed elements was proven to have a significant influence; the best geometric and dimensional representation was observed for parts biggest in size.

We evaluated the dynamics of the diagenetic changes to pig bones incubated for 4, 10, and 31 months in a controlled environment (soil type, moisture and pH, air humidity, and temperature). The criteria for the assessment were as follows: physical parameters (bone weight), biomechanical parameters (compressive strength), bone microstructure (using micro‐computed tomography), and phosphorus and calcium content in the surrounding soil. It was shown that the bone weight decreased the most after 4 months of incubation, whereas the biggest change in the compressive strength was not observed until after 31 months of incubation. Also, the main changes to the bone microstructure were observed in the initial period of degeneration. After 4 months of the experiment, a major drop in the percentage of the thinnest bone trabeculae was noted, whereas a reverse trend was observed for the thickest trabeculae. Moreover, the most significant decrease in the Ca/P ratio in the surrounding soil was observed after the experiment's first 4 months. We conclude that the bioerosion of collagen observed after the initial experimental period was followed by hydroxyapatite chemical decomposition. These results indicate the usefulness of the applied analyses and the feasibility of ensuring a standardized environment for diagenetic research.

Research in the field of spinal biomechanics, including analyses of the impact of implants on the stability of the spine, is conducted extensively in animal models. One of the basic problems in spinal implantation is the transfer and distribution of loads carried by the spine on the surfaces of the vertebral bodies. An important factor in proper cooperation of spinal implants with the vertebrae is the endplate (EP), which is why the EP in the animal model used for testing should be as similar as possible to the human EP. Therefore, this study involved multiscale structural and morphometric analyses of the animal models most commonly used in spinal biomechanics research, i.e. pig, ovine, and bovine tail. The tests were performed on 28 lumbar porcine, ovine, and bovine vertebrae. Both cranial and caudal EPs were analysed in three selected areas: anterior, middle, and posterior EPs. The conducted tests included a morphometric analysis of the trabecular bone (TB) layer of the EP as well as microscopic analysis at the mesoscale (total thickness) and microscale (thickness of the individual EP layers). The porcine EP had a characteristic increased circumferential thickness (~3 mm) with a significant narrowing in the central region (50%–60%). The convex cranial ovine EP had a constant thickness throughout the cross‐section and the concave caudal EP showed ~35% narrowing in the central region. The thickest EPs were observed in the bovine tail model with negligibly small narrowing in the central region (~5%). The thickness of the cartilaginous layer in the porcine and bovine models reached up to 1 mm in the peripheral regions and decreased in the central part. The growth plate layer had a similar thickness in all the models. On the other hand, the narrowing of the total thickness of the EPs in the central region was mainly due to a decrease in the VEP thickness. In the ovine and bovine models, the central region of the EP was characterized by large isotropy and trabeculae of mixed or rod‐like shape. By contrast, in the pig, this region had plate‐like trabeculae of anisotropic nature. The porcine model was identified as best reflecting the shape and structure of the human EP and as the best surrogate model for the human EP model. This choice is particularly important in the context of biomechanical research.

Background: Idiopathic scoliosis is the most common pathology of the children's spine, identified as spine lateral curvature with Cobb angle greater than 10 deg. The rapid development of technology allows, even mobile devices, to perform a quick and cheap diagnosis ensuring an accuracy similar to the Bunnell scoliometer. Objective: The study aimed to validate the accuracy of a newly developed accessory for measuring the angle of trunk rotation (ATR) using mobile devices. Methods: ATR measurements were carried out on a group of 30 adults using three diagnostic tools: the Bunnell scoliometer, Scolioscreen, and mScolio designed by the authors. Scolioscreen and mScolio were used together with a smartphone and the Clinometer app. Three measurements were performed using each of the methods. Results: The greatest data discrepancy was obtained between the Bunnell scoliometer and Scolioscreen (–3.7 ÷ 4.4 deg) and was twice larger than between the Bunnell scoliometer and mScolio (–1.8 ÷ 2.1 deg). The excellent agreement was obtained for the mScolio device, where the concordance correlation coefficient was 0.9381 (95% CI of 0.9076 ÷ 0.9588) and the interclass correlation coefficient was 0.9501 (95% CI of 0.9242 ÷ 0.9671). Conclusions: Tests showed excellent reliability and validity of ATR using the mScolio solution. Obtained results show excellent consistency between mScolio and the Brunnell scoliometer measurements.

The project “Recovery from bone loss, diminished mineral density and strength in mice after treatment with steroidal and nonsteroidal anti-inflammatory drugs by injection of exosomes enriched with agomir miRNAs” is an animal experiment project, and an attempt to apply small RNA strands to reverse the harmful effects of anti-inflammatory drugs. Patients chronically treated with an anti-inflammatory drug suffer from musculoskeletal side effects, including reversed mineralisation and disabled bone fracture healing. The aims of the study are to measure changes in bone mineral density and bone strength in mice treated with methylprednisolone or diclofenac in combination with treadmill exercise. The reversal of the negative effects of these drugs will be assayed using modified miRNA agomir. Bones obtained from the treated mice will be analysed using micro-CT, dynamic mechanical analysis (DMA), nanoindentation, Raman spectroscopy and gene expression. We expect to find specific miRNA counteracting the demineralisation of the mice bones caused by methylprednisolone or diclofenac.