The MyoRobot: A novel automated biomechatronics system to assess voltage/Ca2+ biosensors and active/passive biomechanics in muscle and biomaterials

Haug, Michael; Reischl, Barbara; Prölß, Gerhard; Pollmann, Charlotte; Buckert, Thomas; Keidel, C.; Schürmann, Sebastian; Höck, Michael; Rupitsch, Stefan J.; Heckel, Maria; Pöschel, Thorsten; Scheibel, Thomas; Haynl, Christian; Kiriaev, Leonit; Head, Sl; Friedrich, Oliver

doi:10.1016/j.bios.2017.12.003

Cited by 27 publications

(67 citation statements)

References 45 publications

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“…For human R350P desminopathy, apart from clinical assessment of overall force in proximal and distal muscle groups according to MRC grades Walter et al (2007) , no information on active force production on the sub-organ level (single fibers, fiber bundles) is available. For the murine R349P desmin knock-in model, initial characterization of small SOL fiber bundles at preclinical stages in young mice Clemen et al (2015) as well as very recently, a whole age-dependent study of ours on small EDL and SOL fiber bundles in mice from 17wks to >60wks of age, documented a pre-aged phenotype regarding increased passive axial stiffness, using our novel high-end MyoRobot biomechatronics system Hauget al (2018) . Together with the finding of also increased extracellular fibrosis in aged R349P desmin knock-in muscles Diermeier et al (2017a) , this still leaves the possibility of series-elastic elements of increased stiffness in parallel to the cytoskeletal visco-elastic elements to be responsible for the reduced axial compliance in small EDL and SOL fiber bundles seen before.…”

Section: Discussionmentioning

confidence: 79%

“…unloaded speed of shortening. To address this question, we performed so-called ‘slack-tests’ using our automated MyoRobot system Haug et al (2018) . Fig.…”

Section: Resultsmentioning

confidence: 99%

“…5C the statistical analysis of v fast and v slow . V fast reflects the initial, unloaded phase, whereas v slow represents the internally loaded phase that occurs while taking up larger ‘slacks lengths’ Haug et al (2018) . Notably, v fast increased with age in all genotypes, while it decreased again in senile mutation-bearing fibers, except for hom SOL fibers.…”

Section: Resultsmentioning

confidence: 99%

“…With our recent implementation of a VCA within the MyoRobot Haug et al (2018) , it was now possible to address whether the markedly increased axial stiffness in single fibers in the R349P desmin knock-in background would impact on unloaded shortening, given the fact that the isometric maximum force development was only marginally affected. The absolute values of velocities for the fast component with mean values between 4mm/s and 12mm/s for EDL single fibers and 2 - 6mm/s for SOL fibers are well in the range of velocities reported for single EDL fibers from wt mice unrelated to this study Haug et al (2018) . This demonstrates the robustness of our automated biomechatronics system to assess active biomechanical properties in single fibers across studies and organ scales.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, biomechanical analyses of small fiber bundles, initially in slow-twitch, load-bearing M. soleus (SOL) from young het and hom R349P desmin mice, showed a marked increase in passive bundle stiffness compared to wt bundles Clemen et al (2015); Diermeier et al (2017a) . Since robust biomechanical experiments in small muscle fiber bundle preparations are difficult to carry out and require precise actuation to record steady-state resting length tension curves at slow strain speeds, we engineered a novel automated biomechatronics system that also contains a sensitive force transducer technology for recordings of active and passive axial muscle forces Haug et al (2018) . Alongside with the ongoing engineering progress, our system was also systematically validated extending our previous recordings in SOL bundles from R349P desmin mice not only to the fast-twitch extensor digitorum longus (EDL) muscle, but also to a wide age range from young (17-23 weeks) to aged (60-80 weeks) animals Haug et al (2019) .…”

Section: Introductionmentioning

confidence: 99%

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Growing old too early, automated assessment of skeletal muscle single fiber biomechanics in ageing R349P desmin knock-in mice using the MyoRobot technology

Meyer

Haug

Reischl

et al. 2019

Preprint

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Growing old too early, automated 1 assessment of skeletal muscle single 2 fiber biomechanics in ageing R349P 3 desmin knock-in mice using the 4 MyoRobot technology 5Abstract Muscle biomechanics is determined by active motor-protein assembly and passive 28 strain transmission through cytoskeletal structures. The extrasarcomeric desmin filament network 29 aligns myofibrils at the z-discs, provides nuclear-sarcolemmal anchorage and may also serve as 30 memory for muscle repositioning following large strains. Our previous analyses of R349P desmin 31 knock-in mice, an animal model for the human R350P desminopathy, already depicted pre-clinical 32 changes in myofibrillar arrangement and increased fiber bundle stiffness compatible with a 33 pre-aged phenotype in the disease. Since the specific effect of R349P desmin on axial 34 biomechanics in fully differentiated muscle fibers is unknown, we used our automated MyoRobot 35 biomechatronics platform to compare passive and active biomechanics in single fibers derived 36 from fast-and slow-twitch muscles from adult to senile mice hetero-or homozygous for this 37 desmin mutation with wild-type littermates. Experimental protocols involved caffeine-induced 38 Ca 2+ -mediated force transients, pCa-force curves, resting length-tension curves, visco-elasticity and 39 'slack-tests'. We demonstrate that the presence of R349P desmin predominantly increased single 40 fiber axial stiffness in both muscle types with a pre-aged phenotype over wild-type fibers. Axial 41 viscosity was unaffected. Likewise, no systematic changes in Ca 2+ -mediated force properties were 42 found. Notably, mutant single fibers showed faster unloaded shortening over wild-type fibers. 43 Effects of ageing seen in the wild-type always appeared earlier in the mutant desmin fibers. 44 Impaired R349P desmin muscle biomechanics is clearly an effect of a compromised intermediate 45 filament network rather than secondary to fibrosis. 46 47 48 Skeletal muscle is the largest organ system of the body and under constant mechanical stress, either 49 due to passive strain or through active contraction producing axial and lateral stresses. While lateral 50 forces are distributed between single fibers across anchorage points in the extracellular matrix 51 (ECM) to the intracellular cytoskeleton via the dystrophin-glycoprotein complex (DGC) Ramaswamy 52 et al. (2011) and focal adhesion complexes Ra et al. (1999), axial forces are distributed through 53 contractile (active) and non-contractile (passive) elements. Apart from the giant, roughly 1.5 m 54 long elastomeric protein titin, being responsible for the visco-elastic properties of single muscle 55 fibers through unfolding of globular domains under strain Mártonfalvi and Kellermayer (2014); 56 Powers et al. (2018), connecting proteins of the extra-sarcomeric intermediate filament (IF) family 57 may also be a vital determinant of axial elasticity. An important member of the IFs is the type 58 III filament protein desmin, transversely linking adjacent myofibri...

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Section: Discussionmentioning

confidence: 79%

“…unloaded speed of shortening. To address this question, we performed so-called ‘slack-tests’ using our automated MyoRobot system Haug et al (2018) . Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Growing old too early, automated assessment of skeletal muscle single fiber biomechanics in ageing R349P desmin knock-in mice using the MyoRobot technology

Meyer

Haug

Reischl

et al. 2019

Preprint

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SEMPAI: a Self‐Enhancing Multi‐Photon Artificial Intelligence for Prior‐Informed Assessment of Muscle Function and Pathology

et al. 2023

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Deep learning (DL) shows notable success in biomedical studies. However, most DL algorithms work as black boxes, exclude biomedical experts, and need extensive data. This is especially problematic for fundamental research in the laboratory, where often only small and sparse data are available and the objective is knowledge discovery rather than automation. Furthermore, basic research is usually hypothesis‐driven and extensive prior knowledge (priors) exists. To address this, the Self‐Enhancing Multi‐Photon Artificial Intelligence (SEMPAI) that is designed for multiphoton microscopy (MPM)‐based laboratory research is presented. It utilizes meta‐learning to optimize prior (and hypothesis) integration, data representation, and neural network architecture simultaneously. By this, the method allows hypothesis testing with DL and provides interpretable feedback about the origin of biological information in 3D images. SEMPAI performs multi‐task learning of several related tasks to enable prediction for small datasets. SEMPAI is applied on an extensive MPM database of single muscle fibers from a decade of experiments, resulting in the largest joint analysis of pathologies and function for single muscle fibers to date. It outperforms state‐of‐the‐art biomarkers in six of seven prediction tasks, including those with scarce data. SEMPAI's DL models with integrated priors are superior to those without priors and to prior‐only approaches.

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Impact of prolonged sepsis on neural and muscular components of muscle contractions in a mouse model

Goossens

Weckx

Derde

et al. 2021

J cachexia sarcopenia muscle

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Background Prolonged critically ill patients frequently develop debilitating muscle weakness that can affect both peripheral nerves and skeletal muscle. In‐depth knowledge on the temporal contribution of neural and muscular components to muscle weakness is currently incomplete. Methods We used a fluid‐resuscitated, antibiotic‐treated, parenterally fed murine model of prolonged (5 days) sepsis‐induced muscle weakness (caecal ligation and puncture; n = 148). Electromyography (EMG) measurements were performed in two nerve–muscle complexes, combined with histological analysis of neuromuscular junction denervation, axonal degeneration, and demyelination. In situ muscle force measurements distinguished neural from muscular contribution to reduced muscle force generation. In myofibres, imaging and biomechanics were combined to evaluate myofibrillar contractile calcium sensitivity, sarcomere organization, and fibre structural properties. Myosin and actin protein content and titin gene expression were measured on the whole muscle. Results Five days of sepsis resulted in increased EMG latency (P = 0.006) and decreased EMG amplitude (P < 0.0001) in the dorsal caudal tail nerve–tail complex, whereas only EMG amplitude was affected in the sciatic nerve–gastrocnemius muscle complex (P < 0.0001). Myelin sheath abnormalities (P = 0.2), axonal degeneration (number of axons; P = 0.4), and neuromuscular junction denervation (P = 0.09) were largely absent in response to sepsis, but signs of axonal swelling [higher axon area (P < 0.0001) and g‐ratio (P = 0.03)] were observed. A reduction in maximal muscle force was present after indirect nerve stimulation (P = 0.007) and after direct muscle stimulation (P = 0.03). The degree of force reduction was similar with both stimulations (P = 0.2), identifying skeletal muscle, but not peripheral nerves, as the main contributor to muscle weakness. Myofibrillar calcium sensitivity of the contractile apparatus was unaffected by sepsis (P ≥ 0.6), whereas septic myofibres displayed disorganized sarcomeres (P < 0.0001) and altered myofibre axial elasticity (P < 0.0001). Septic myofibres suffered from increased rupturing in a passive stretching protocol (25% more than control myofibres; P = 0.04), which was associated with impaired myofibre active force generation (P = 0.04), linking altered myofibre integrity to function. Sepsis also caused a reduction in muscle titin gene expression (P = 0.04) and myosin and actin protein content (P = 0.05), but not the myosin‐to‐actin ratio (P = 0.7). Conclusions Prolonged sepsis‐induced muscle weakness may predominantly be related to a disruption in myofibrillar cytoarchitectural structure, rather than to neural abnormalities.

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The MyoRobot: A novel automated biomechatronics system to assess voltage/Ca2+ biosensors and active/passive biomechanics in muscle and biomaterials

Cited by 27 publications

References 45 publications

Growing old too early, automated assessment of skeletal muscle single fiber biomechanics in ageing R349P desmin knock-in mice using the MyoRobot technology

Growing old too early, automated assessment of skeletal muscle single fiber biomechanics in ageing R349P desmin knock-in mice using the MyoRobot technology

SEMPAI: a Self‐Enhancing Multi‐Photon Artificial Intelligence for Prior‐Informed Assessment of Muscle Function and Pathology

Impact of prolonged sepsis on neural and muscular components of muscle contractions in a mouse model

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