Ostarine blunts the effect of endurance training on submaximal endurance in rats.

The purpose of this study is to study the effects of ostarine alone and in combination with endurance training in sexually mature, male Wistar rats. The rats were divided into a treadmill-trained group and a sedentary group. Half of each group received either ostarine or vehicle for 8 weeks (n = 10 each, in total n = 40). We examined some functional, hormonal, and anthropometric parameters and the myogenic gene expression of myostatin, insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor-A (VEGF-A) in m. gastrocnemius. Ostarine decreased submaximal endurance and increased myogenic gene expression of myostatin but had no effect on maximal time to exhaustion and grip strength. Training increased submaximal endurance, maximal time to exhaustion, and grip strength. Our results indicate that both exercise and ostarine treatment had no significant effects on serum levels of luteinizing hormone, follicle-stimulating hormone, and testosterone, or on the myogenic gene expression of IGF-1 and VEGF-A. Neither ostarine nor the training had a significant effect on the testis, liver, and heart weights. In conclusion, ostarine had no effect on anthropometric and hormonal parameters but increased the myostatin gene expression in muscle. The SARM treatment decreased submaximal endurance without affecting maximal time to exhaustion, and training increased both metrics.

Negative Pressure Wound Therapy in Free Muscle Flaps-Risk or Benefit?

BACKGROUND: Application of negative pressure wound therapy (NPWT) on free flaps not only reduces edema but also increases the pressure from outside. The impact of these opposite effects on flap perfusion remains elusive. This study evaluates the NPWT system's influence on macro- and microcirculation of free flaps and edema reduction to better assess the clinical value of this therapy in microsurgical reconstructions. METHODS: In this open-label, prospective cohort study, a total of 26 patients with free gracilis muscle flaps for distal lower extremity reconstruction were included. Flaps were covered with an NPWT (13 patients) or a conventional, fatty gauze dressing (13 patients) for 5 postoperative days (PODs). Changes in flap perfusion were analyzed by laser Doppler flowmetry, remission spectroscopy, and an implanted Doppler probe. Flap volume as a surrogate parameter for flap edema was evaluated by three-dimensional (3D) scans. RESULTS: No flap showed clinical evidence of circulatory disturbances. The groups showed significant differences in the dynamic of macrocirculatory blood flow velocity with an increase in the NPWT group and a decelerated flow in the control group from PODs 0 to 3 and PODs 3 to 5. No significant differences in microcirculation parameters were observed. 3D scans for estimation of edema development demonstrated significant differences in volume dynamics between the groups. Flap volume of the controls increased, while the volume in the NPWT group decreased during the first 5 PODs. The volume of NPWT-treated flaps decreased even further after NPWT removal from PODs 5 to 14 and significantly more than the flap volume in the control group. CONCLUSION: NPWT is a safe form of dressing for free muscle flaps that enhances blood flow and results in a sustainable edema reduction. The use of NPWT dressings for free flaps should therefore be considered not only as a pure wound covering but also as a supportive therapy for free tissue transfer.

Combining Surgical Innovations in Amputation Surgery-Robotic Harvest of the Rectus Abdominis Muscle, Transplantation and Targeted Muscle Reinnervation Improves Myocontrol Capability and Pain in a Transradial Amputee.

Adding robotic surgery to bionic reconstruction might open a new dimension. The objective was to evaluate if a robotically harvested rectus abdominis (RA) transplant is a feasible procedure to improve soft-tissue coverage at the residual limb (RL) and serve as a recipient for up to three nerves due to its unique architecture and to allow the generation of additional signals for advanced myoelectric prosthesis control. A transradial amputee with insufficient soft-tissue coverage and painful neuromas underwent the interventions and was observed for 18 months. RA muscle was harvested using robotic-assisted surgery and transplanted to the RL, followed by end-to-end neurroraphy to the recipient nerves of the three muscle segments to reanimate radial, median, and ulnar nerve function. The transplanted muscle healed with partial necrosis of the skin mesh graft. Twelve months later, reliable, and spatially well-defined Hoffmann-Tinel signs were detectable at three segments of the RA muscle flap. No donor-site morbidities were present, and EMG activity could be detected in all three muscle segments. The linear discriminant analysis (LDA) classifier could reliably distinguish three classes within 1% error tolerance using only the three electrodes on the muscle transplant and up to five classes outside the muscle transplant. The combination of these surgical procedure advances with emerging (myo-)control technologies can easily be extended to different amputation levels to reduce RL complications and augment control sites with a limited surface area, thus facilitating the usability of advanced myoelectric prostheses.

Therapeutic Consequences of Targeting the IGF-1/PI3K/AKT/FOXO3 Axis in Sarcopenia: A Narrative Review.

The high prevalence of sarcopenia in an aging population has an underestimated impact on quality of life by increasing the risk of falls and subsequent hospitalization. Unfortunately, the application of the major established key therapeutic-physical activity-is challenging in the immobile and injured sarcopenic patient. Consequently, novel therapeutic directions are needed. The transcription factor Forkhead-Box-Protein O3 (FOXO3) may be an option, as it and its targets have been observed to be more highly expressed in sarcopenic muscle. In such catabolic situations, Foxo3 induces the expression of two muscle specific ubiquitin ligases (Atrogin-1 and Murf-1) via the PI3K/AKT pathway. In this review, we particularly evaluate the potential of Foxo3-targeted gene therapy. Foxo3 knockdown has been shown to lead to increased muscle cross sectional area, through both the AKT-dependent and -independent pathways and the reduced impact on the two major downstream targets Atrogin-1 and Murf-1. Moreover, a Foxo3 reduction suppresses apoptosis, activates satellite cells, and initiates their differentiation into muscle cells. While this indicates a critical role in muscle regeneration, this mechanism might exhaust the stem cell pool, limiting its clinical applicability. As systemic Foxo3 knockdown has also been associated with risks of inflammation and cancer progression, a muscle-specific approach would be necessary. In this review, we summarize the current knowledge on Foxo3 and conceptualize a specific and targeted therapy that may circumvent the drawbacks of systemic Foxo3 knockdown. This approach presumably would limit the side effects and enable an activity-independent positive impact on skeletal muscle.

Why Hard Code the Bionic Limbs When They Can Learn From Humans?

In this paper, we propose a task-generic learning-based model for the control of a powered ankle exoskeleton. In contrast to the traditional state machine-based control approaches that hard codes the transition heuristics for the different states and motion conditions during gait, we propose to learn the finer constraints of gait from multiple demonstrations of human gait. We validate our proposed approach on a dataset of ten subjects walking on various inclines and at multiple speeds. We deploy our model on an ankle exoskeleton, and conduct user studies on able-bodied subjects who perform gait scenarios across varying speeds and inclines. We conduct multiple online experiments to validate our learning-based approach for different motion conditions, e.g., normal walking, walking at different speeds and inclines, turns, cross-overs with variable speed and cadence, walking on a treadmill as well as on level ground. We find that our proposed learning-based model has the capability to extrapolate its learned decision rules to support untrained gait conditions, for, e.g., walking at higher speeds and inclines not seen during training. The subjects were able to adapt to the different gait scenarios comfortably without loss of stability.

Effects of Iliosacral Joint Immobilization on Walking after Iliosacral Screw Fixation in Humans.

BACKGROUND: Pelvis fractures are commonly stabilized by surgical implants to facilitate their healing. However, such implants immobilize the iliosacral joint for up to a year until removal. We report how iliosacral joint immobilization affects the walking of patients. METHODS: The gaits of patients with immobilized sacroiliac joints after unstable pelvic fracture (n = 8; mean age: 45.63 ± 23.19; five females and three males) and sex- and age-matched healthy control individuals (n = 8; mean age: 46.50 ± 22.91; five females and three males) were recorded and analyzed using a motion capture system. The forces between the tread and feet were also recorded. Standard gait parameters as well as dynamic patterns of joint angles and moments of the lower extremities were analyzed using the simulation software OpenSim. RESULTS: With the exception of hip extensor strength, the monitored joint parameters of the patients showed task-dependent deviations during walking, i.e., plantarflexor force was increased when stepping on an elevated surface, as were hip flexion and extensor moments, knee flexion and extensor moments, as well as ankle dorsiflexion and the associated negative plantarflexor force during stance on the elevated surface. CONCLUSIONS: Iliosacral joint fixation causes reduced forward and upward propulsion and requires an extended range of hip motion in the sagittal plane. Patients show significant mobility limitation after iliosacral screw fixation.

Spatial correlation of 2D hard-tissue histology with 3D microCT scans through 3D printed phantoms.

Hard-tissue histology-the analysis of thin two-dimensional (2D) sections-is hampered by the opaque nature of most biological specimens, especially bone. Therefore, the cutting process cannot be assigned to regions of interest. In addition, the applied cutting-grinding method is characterized by significant material loss. As a result, relevant structures might be missed or destroyed, and 3D features can hardly be evaluated. Here, we present a novel workflow, based on conventual microCT scans of the specimen prior to the cutting process, to be used for the analysis of 3D structural features and for directing the sectioning process to the regions of interest. 3D printed fiducial markers, embedded together with the specimen in resin, are utilized to retrospectively register the obtained 2D histological images into the 3D anatomical context. This not only allows to identify the cutting position, but also enables the co-registration of the cell and extracellular matrix morphological analysis to local 3D information obtained from the microCT data. We have successfully applied our new approach to assess hard-tissue specimens of different species. After matching the predicted microCT cut plane with the histology image, we validated a high accuracy of the registration process by computing quality measures namely Jaccard and Dice similarity coefficients achieving an average score of 0.90 ± 0.04 and 0.95 ± 0.02, respectively. Thus, we believe that the novel, easy to implement correlative imaging approach holds great potential for improving the reliability and diagnostic power of classical hard-tissue histology.

Foxo3 Knockdown Mediates Decline of Myod1 and Myog Reducing Myoblast Conversion to Myotubes.

Sarcopenia has a high prevalence among the aging population. Sarcopenia is of tremendous socioeconomic importance because it can lead to falls and hospitalization, subsequently increasing healthcare costs while limiting quality of life. In sarcopenic muscle fibers, the E3 ubiquitin ligase F-Box Protein 32 (Fbxo32) is expressed at substantially higher levels, driving ubiquitin-proteasomal muscle protein degradation. As one of the key regulators of muscular equilibrium, the transcription factor Forkhead Box O3 (FOXO3) can increase the expression of Fbxo32, making it a possible target for the regulation of this detrimental pathway. To test this hypothesis, murine C2C12 myoblasts were transduced with AAVs carrying a plasmid for four specific siRNAs against Foxo3. Successfully transduced myoblasts were selected via FACS cell sorting to establish single clone cell lines. Sorted myoblasts were further differentiated into myotubes and stained for myosin heavy chain (MHC) by immunofluorescence. The resulting area was calculated. Myotube contractions were induced by electrical stimulation and quantified. We found an increased Foxo3 expression in satellite cells in human skeletal muscle and an age-related increase in Foxo3 expression in older mice in silico. We established an in vitro AAV-mediated FOXO3 knockdown on protein level. Surprisingly, the myotubes with FOXO3 knockdown displayed a smaller myotube size and a lower number of nuclei per myotube compared to the control myotubes (AAV-transduced with a functionless control plasmid). During differentiation, a lower level of FOXO3 reduced the expression Fbxo32 within the first three days. Moreover, the expression of Myod1 and Myog via ATM and Tp53 was reduced. Functionally, the Foxo3 knockdown myotubes showed a higher contraction duration and time to peak. Early Foxo3 knockdown seems to terminate the initiation of differentiation due to lack of Myod1 expression, and mediates the inhibition of Myog. Subsequently, the myotube size is reduced and the excitability to electrical stimulation is altered.

MR-Imaging in Osteoarthritis: Current Standard of Practice and Future Outlook.

Osteoarthritis (OA) is a common degenerative joint disease that affects millions of people worldwide. Magnetic resonance imaging (MRI) has emerged as a powerful tool for the evaluation and monitoring of OA due to its ability to visualize soft tissues and bone with high resolution. This review aims to provide an overview of the current state of MRI in OA, with a special focus on the knee, including protocol recommendations for clinical and research settings. Furthermore, new developments in the field of musculoskeletal MRI are highlighted in this review. These include compositional MRI techniques, such as T2 mapping and T1rho imaging, which can provide additional important information about the biochemical composition of cartilage and other joint tissues. In addition, this review discusses semiquantitative joint assessment based on MRI findings, which is a widely used method for evaluating OA severity and progression in the knee. We analyze the most common scoring methods and discuss potential benefits. Techniques to reduce acquisition times and the potential impact of deep learning in MR imaging for OA are also discussed, as these technological advances may impact clinical routine in the future.

Effects of ligandrol as a selective androgen receptor modulator in a rat model for osteoporosis.

INTRODUCTION: The selective androgen receptor modulator ligandrol (LGD-4033 or VK5211) has been shown to improve muscle tissue. In the present study, the effect of ligandrol on bone tissue was investigated in ovariectomized rat model. MATERIALS AND METHODS: Three-month-old Sprague Dawley rats were either ovariectomized (OVX, n = 60) or left intact (NON-OVX, n = 15). After 9 weeks, OVX rats were divided into four groups: untreated OVX (n = 15) group and three OVX groups (each of 15 rats) treated with ligandrol orally at doses of 0.03, 0.3, or 3 mg/kg body weight. After five weeks, lumbar vertebral bodies (L), tibiae, and femora were examined using micro-computed tomographical, biomechanical, ashing, and gene expression analyses. RESULTS: In the 3-mg ligandrol group, bone structural properties were improved (trabecular number: 38 ± 8 vs. 35 ± 7 (femur), 26 ± 7 vs. 22 ± 6 (L), 12 ± 5 vs. 6 ± 3 (tibia) and serum phosphorus levels (1.81 ± 0.17 vs.1.41 ± 0.17 mmol/l), uterus (0.43 ± 0.04 vs. 0.11 ± 0.02 g), and heart (1.13 ± 0.11 vs. 1.01 ± 0.08 g) weights were increased compared to the OVX group. Biomechanical parameters were not changed. Low and medium doses did not affect bone tissue and had fewer side effects. Body weight and food intake were not affected by ligandrol; OVX led to an increase in these parameters and worsened all bone parameters. CONCLUSION: Ligandrol at high dose showed a subtle anabolic effect on structural properties without any improvement in biomechanical properties of osteoporotic bones. Considering side effects of ligandrol at this dose, its further investigation for the therapy of postmenopausal osteoporosis should be reevaluated.

Hypoxia Preconditioned Serum (HPS) Promotes Proliferation and Chondrogenic Phenotype of Chondrocytes In Vitro.

Autologous chondrocyte implantation (ACI) for the treatment of articular cartilage defects remains challenging in terms of maintaining chondrogenic phenotype during in vitro chondrocyte expansion. Growth factor supplementation has been found supportive in improving ACI outcomes by promoting chondrocyte redifferentiation. Here, we analysed the chondrogenic growth factor concentrations in the human blood-derived secretome of Hypoxia Preconditioned Serum (HPS) and assessed the effect of HPS-10% and HPS-40% on human articular chondrocytes from osteoarthritic cartilage at different time points compared to normal fresh serum (NS-10% and NS-40%) and FCS-10% culture conditions. In HPS, the concentrations of TGF-beta1, IGF-1, bFGF, PDGF-BB and G-CSF were found to be higher than in NS. Chondrocyte proliferation was promoted with higher doses of HPS (HPS-40% vs. HPS-10%) and longer stimulation (4 vs. 2 days) compared to FCS-10%. On day 4, immunostaining of the HPS-10%-treated chondrocytes showed increased levels of collagen type II compared to the other conditions. The promotion of the chondrogenic phenotype was validated with quantitative real-time PCR for the expression of collagen type II (COL2A1), collagen type I (COL1A1), SOX9 and matrix metalloproteinase 13 (MMP13). We demonstrated the highest differentiation index (COL2A1/COL1A1) in HPS-10%-treated chondrocytes on day 4. In parallel, the expression of differentiation marker SOX9 was elevated on day 4, with HPS-10% higher than NS-10/40% and FCS-10%. The expression of the cartilage remodelling marker MMP13 was comparable across all culture conditions. These findings implicate the potential of HPS-10% to improve conventional FCS-based ACI culture protocols by promoting the proliferation and chondrogenic phenotype of chondrocytes during in vitro expansion.

Comparison of the Effect of Different Conditioning Media on the Angiogenic Potential of Hypoxia Preconditioned Blood-Derived Secretomes: Towards Engineering Next-Generation Autologous Growth Factor Cocktails.

Hypoxia Preconditioned Plasma (HPP) and Serum (HPS) are regenerative blood-derived growth factor compositions that have been extensively examined for their angiogenic and lymphangiogenic activity towards wound healing and tissue repair. Optimization of these secretomes' growth factor profile, through adjustments of the conditioning parameters, is a key step towards clinical application. In this study, the autologous liquid components (plasma/serum) of HPP and HPS were replaced with various conditioning media (NaCl, PBS, Glucose 5%, AIM V medium) and were analyzed in terms of key pro- (VEGF-A, EGF) and anti-angiogenic (TSP-1, PF-4) protein factors, as well as their ability to promote microvessel formation in vitro. We found that media substitution resulted in changes in the concentration of the aforementioned growth factors, and also influenced their ability to induce angiogenesis. While NaCl and PBS led to a lower concentration of all growth factors examined, and consequently an inferior tube formation response, replacement with Glucose 5% resulted in increased growth factor concentrations in anticoagulated blood-derived secretomes, likely due to stimulation of platelet factor release. Medium substitution with Glucose 5% and specialized peripheral blood cell-culture AIM V medium generated comparable tube formation to HPP and HPS controls. Altogether, our data suggest that medium replacement of plasma and serum may significantly influence the growth factor profile of hypoxia-preconditioned blood-derived secretomes and, therefore, their potential application as tools for promoting therapeutic angiogenesis.

In Vitro Comparison of Lymphangiogenic Potential of Hypoxia Preconditioned Serum (HPS) and Platelet-Rich Plasma (PRP).

Strategies for therapeutic lymphangiogenesis are gradually directed toward the use of growth factor preparations. In particular, blood-derived growth factor products, including Hypoxia Preconditioned Serum (HPS) and Platelet-rich Plasma (PRP), are both clinically employed for accelerating tissue repair and have received considerable attention in the field of regenerative medicine research. In this study, a comparative analysis of HPS and PRP was conducted to explore their lymphangiogenic potential. We found higher pro-lymphangiogenic growth factor concentrations of VEGF-C, PDGF-BB, and bFGF in HPS in comparison to normal serum (NS) and PRP. The proliferation and migration of lymphatic endothelial cells (LECs) were promoted considerably with both HPS and PRP, but the strongest effect was achieved with HPS-40% dilution. Tube formation of LECs showed the highest number of tubes, branching points, greater tube length, and cell-covered area with HPS-10%. Finally, the effects were double-validated using an ex vivo lymphatic ring assay, in which the highest number of sprouts and the greatest sprout length were achieved with HPS-10%. Our findings demonstrate the superior lymphangiogenic potential of a new generation blood-derived secretome obtained by hypoxic preconditioning of peripheral blood cells-a method that offers a novel alternative to PRP.

Current Approaches for Image Fusion of Histological Data with Computed Tomography and Magnetic Resonance Imaging.

Classical analysis of biological samples requires the destruction of the tissue's integrity by cutting or grinding it down to thin slices for (Immuno)-histochemical staining and microscopic analysis. Despite high specificity, encoded in the stained 2D section of the whole tissue, the structural information, especially 3D information, is limited. Computed tomography (CT) or magnetic resonance imaging (MRI) scans performed prior to sectioning in combination with image registration algorithms provide an opportunity to regain access to morphological characteristics as well as to relate histological findings to the 3D structure of the local tissue environment. This review provides a summary of prevalent literature addressing the problem of multimodal coregistration of hard- and soft-tissue in microscopy and tomography. Grouped according to the complexity of the dimensions, including image-to-volume (2D ⟶ 3D), image-to-image (2D ⟶ 2D), and volume-to-volume (3D ⟶ 3D), selected currently applied approaches are investigated by comparing the method accuracy with respect to the limiting resolution of the tomography. Correlation of multimodal imaging could position itself as a useful tool allowing for precise histological diagnostic and allow the a priori planning of tissue extraction like biopsies.

Nucleic acid direct delivery to fibroblasts: a review of nucleofection and applications.

The fibroblast is one of the ideal target cell candidates for cell-based gene therapy approaches to promote tissue repair. Gene delivery to fibroblasts by viral transfection has been confirmed to have high transfection efficiency. However, in addition to immunogenic effects of viruses, the random integration of viral genes may damage the genome, affect the cell phenotype or even cause cancerous mutations in the transfected cells. Due to these potential biohazards and unknown long-term risks, the clinical use of viral transfection has been very limited. In contrast, initial non-viral transfection methods have been simple and safe to implement, with low immunogenicity, insertional mutagenesis, and risk of carcinogenesis, but their transfection efficiency has been relatively low. Nucleofection, a more recent non-viral transfection method, now combines the advantages of high transfection efficiency and direct nucleic acid delivery to the nucleus with a high safety.Here, we reviewed recent articles on fibroblast nucleofection, summarized different research points, improved methods and application scopes, and opened up ideas for promoting the further improvement and development of fibroblast nucleofection to meet the needs of a variety of disease research and clinical applications.

Vibrotactile mapping of the upper extremity: Absolute perceived intensity is location-dependent; perception of relative changes is not.

Vibrotactile sensation is an essential part of the sense of touch. In this study, the localized vibrotactile sensation of the arm-shoulder region was quantified in 10 able-bodied subjects. For this analysis, the six relevant dermatomes (C3-T2) and three segments-the lower arm, the upper arm, and the shoulder region were studied. For psychometric evaluation, tasks resulting in the quantification of sensation threshold, just noticeable difference, Weber fraction, and perception of dynamically changing vibrotactile stimuli were performed. We found that healthy subjects could reliably detect vibration in all tested regions at low amplitude (2-6% of the maximal amplitude of commonly used vibrotactors). The detection threshold was significantly lower in the lower arm than that in the shoulder, as well as ventral in comparison with the dorsal. There were no significant differences in Weber fraction (20%) detectable between the studied locations. A compensatory tracking task resulted in a significantly higher average rectified error in the shoulder than that in the upper arm, while delay and correlation coefficient showed no difference between the regions. Here, we presented a conclusive map of the vibrotactile sense of the healthy upper limb. These data give an overview of the sensory bandwidth that can be achieved with vibrotactile stimulation at the arm and may help in the design of vibrotactile feedback interfaces (displays) for the hand/arm/shoulder-region.

Topically Confined Enhancement of Cutaneous Microcirculation by Cold Plasma.

INTRODUCTION: We aim to explore potentials and modalities of cold atmospheric pressure plasma (CAP) for the subsequent development of therapies targeting an increased perfusion of the lower leg skin tissue. In this study, we addressed the question whether the microcirculation enhancement is restricted to the tissue in direct contact with plasma or if adjacent tissue might also benefit. METHODS: A dielectric barrier discharge (DBD)-generated CAP device exhibiting an electrode area of 27.5 cm2 was used to treat the anterior lower leg of ten healthy subjects for 4.5 min. Subsequently, hyperspectral imaging was performed to measure the tempospatially resolved characteristics of microcirculation parameters in superficial (up to 1 mm) and deeper (up to 5 mm) skin layers. RESULTS: In the tissue area covered by the plasma electrode, DBD-CAP treatment enhances most of the perfusion parameters. The maximum oxygen saturation increase reached 8%, the near-infrared perfusion index (NIR) increased by a maximum of 4%, and the maximum tissue hemoglobin increase equaled 14%. Tissue water index (TWI) was lower in both the control and the plasma groups, thus not affected by the DBD-CAP treatment. Yet, our study reveals that adjacent tissue is hardly affected by the enhancements in the electrode area, and the effects are locally confined. CONCLUSION: Application of DBD-CAP to the lower leg resulted in enhancement of cutaneous microcirculation that extended 1 h beyond the treatment period with localization to the tissue area in direct contact with the cold plasma. This suggests the possibility of tailoring application schemes for topically confined enhancement of skin microcirculation, e.g., in the treatment of chronic wounds.

Generation and evaluation of input values for computational analysis of transport processes within tissue cultures.

Techniques for tissue culture have seen significant advances during the last decades and novel 3D cell culture systems have become available. To control their high complexity, experimental techniques and their Digital Twins (modelling and computational tools) are combined to link different variables to process conditions and critical process parameters. This allows a rapid evaluation of the expected product quality. However, the use of mathematical simulation and Digital Twins is critically dependent on the precise description of the problem and correct input parameters. Errors here can lead to dramatically wrong conclusions. The intention of this review is to provide an overview of the state-of-the-art and remaining challenges with respect to generating input values for computational analysis of mass and momentum transport processes within tissue cultures. It gives an overview on relevant aspects of transport processes in tissue cultures as well as modelling and computational tools to tackle these problems. Further focus is on techniques used for the determination of cell-specific parameters and characterization of culture systems, including sensors for on-line determination of relevant parameters. In conclusion, tissue culture techniques are well-established, and modelling tools are technically mature. New sensor technologies are on the way, especially for organ chips. The greatest remaining challenge seems to be the proper addressing and handling of input parameters required for mathematical models. Following Good Modelling Practice approaches when setting up and validating computational models is, therefore, essential to get to better estimations of the interesting complex processes inside organotypic tissue cultures in the future.

Psychostimulants Modafinil, Atomoxetine and Guanfacine Impair Bone Cell Differentiation and MSC Migration.

Attention deficit hyperactivity disorder (ADHD) is one of the most common worldwide mental disorders in children, young and adults. If left untreated, the disorder can continue into adulthood. The abuse of ADHD-related drugs to improve mental performance for studying, working and everyday life is also rising. The potentially high number of subjects with controlled or uncontrolled use of such substances increases the impact of possible side effects. It has been shown before that the early ADHD drug methylphenidate influences bone metabolism negatively. This study focused on the influence of three more recent cognitive enhancers, modafinil, atomoxetine and guanfacine, on the differentiation of mesenchymal stem cells to osteoblasts and on their cell functions, including migration. Human mesenchymal stem cells (hMSCs) were incubated with a therapeutic plasma dosage of modafinil, atomoxetine and guanfacine. Gene expression analyses revealed a high beta-2 adrenoreceptor expression in hMSC, suggesting it as a possible pathway to stimulate action. In bone formation assays, all three cognitive enhancers caused a significant decrease in the mineralized matrix and an early slight reduction of cell viability without triggering apoptosis or necrosis. While there was no effect of the three substances on early differentiation, they showed differing effects on the expression of osterix (OSX), receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in the later stages of osteoblast development, suggesting alternative modes of action. All three substances significantly inhibited hMSC migration. This effect could be rescued by a selective beta-blocker (Imperial Chemical Industries ICI-118,551) in modafinil and atomoxetine, suggesting mediation via beta-2 receptor stimulation. In conclusion, modafinil, atomoxetine and guanfacine negatively influence hMSC differentiation to bone-forming osteoblasts and cell migration through different intracellular pathways.

Data-driven Gait-predictive Model for Anticipatory Prosthesis Control.

Physiological movement is pre-planned based on current movement state, proprioception, and environmental cues. This preplanning is necessary to allow efficient use of the viscoelastic properties of musculoskeletal tissues in a 4D-environment. Similarly, efficient use of prosthetic devices needs to compensate for the time it takes to control the system. In this study, we propose a gated recurrent net-based gait predictive model to continuously predict the ankle angles and moments fifty milliseconds in advance based on the past trajectory of the input signals. It was observed that using a single input signal (the shank angle), high accuracy of prediction $(R^{2}\gt 0.91)$ was achieved for both ankle angle and moments on walking trials at a self-selected comfortable speed. The results of our study can be utilised for anticipatory lower-limb prosthesis control where embedded sensor information that reflects a prosthetic user's locomotive intent can be used to predict the required angles and moments in advance for actuating a prosthetic joint.