1
|
Heskamp L, Birkbeck MG, Baxter-Beard D, Hall J, Schofield IS, Elameer M, Whittaker RG, Blamire AM. Motor Unit Magnetic Resonance Imaging (MUMRI) In Skeletal Muscle. J Magn Reson Imaging 2024; 60:2253-2271. [PMID: 38216545 DOI: 10.1002/jmri.29218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 01/14/2024] Open
Abstract
Magnetic resonance imaging (MRI) is routinely used in the musculoskeletal system to measure skeletal muscle structure and pathology in health and disease. Recently, it has been shown that MRI also has promise for detecting the functional changes, which occur in muscles, commonly associated with a range of neuromuscular disorders. This review focuses on novel adaptations of MRI, which can detect the activity of the functional sub-units of skeletal muscle, the motor units, referred to as "motor unit MRI (MUMRI)." MUMRI utilizes pulsed gradient spin echo, pulsed gradient stimulated echo and phase contrast MRI sequences and has, so far, been used to investigate spontaneous motor unit activity (fasciculation) and used in combination with electrical nerve stimulation to study motor unit morphology and muscle twitch dynamics. Through detection of disease driven changes in motor unit activity, MUMRI shows promise as a tool to aid in both earlier diagnosis of neuromuscular disorders and to help in furthering our understanding of the underlying mechanisms, which proceed gross structural and anatomical changes within diseased muscle. Here, we summarize evidence for the use of MUMRI in neuromuscular disorders and discuss what future research is required to translate MUMRI toward clinical practice. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 3.
Collapse
Affiliation(s)
- Linda Heskamp
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
- Department of Radiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Matthew G Birkbeck
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
- Newcastle Biomedical Research Centre (BRC), Newcastle University, Newcastle upon Tyne, UK
- Northern Medical Physics and Clinical Engineering, Freeman Hospital, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Daniel Baxter-Beard
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
| | - Julie Hall
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
- Department of Neuroradiology, Royal Victoria Infirmary, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Ian S Schofield
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
| | - Mathew Elameer
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
- Department of Neuroradiology, Royal Victoria Infirmary, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Roger G Whittaker
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
- Directorate of Clinical Neurosciences, Royal Victoria Infirmary, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Andrew M Blamire
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University, Newcastle Upon Tyne, UK
| |
Collapse
|
2
|
Montgomery KL, Novoa RA, Ko JM, Sanchez GN. Handheld multiphoton and pinhole-free reflectance confocal microscopy enables noninvasive, real-time cross-sectional imaging in skin. Sci Rep 2024; 14:26129. [PMID: 39478114 PMCID: PMC11526003 DOI: 10.1038/s41598-024-76908-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2024] [Accepted: 10/17/2024] [Indexed: 11/02/2024] Open
Abstract
Biopsy-based histology has been the foundation of disease diagnosis and management for over a century. A long-sought goal in dermatology is the development of an imaging modality with sufficient resolution and compositional detail to noninvasively interrogate skin histology in vivo. Here, we describe a system that achieves this goal using cross-sectionally scanned, multimodal microscopy (cross-modal). Cross-modal combines multiphoton and reflectance confocal microscopy into one compact system with coordinated three-axis scanning that preserves optical resolution in cross-section. A custom pinhole-free mechanism employing finite-infinite conjugates further simplifies and stabilizes confocal alignment. Evaluated in participants ages 9-81 and Fitzpatrick skin types (FST) 1-5, cross-modal images revealed histological details analogous to those obtained from traditional biopsied tissue. We observed dermal elastosis in sun-damaged skin, elevated melanin in pigmented skin, basaloid nests in basal cell carcinoma, and elongated rete ridges in seborrheic keratosis, supporting cross-modal's potential to deliver histological insights noninvasively.
Collapse
Affiliation(s)
| | - Roberto A Novoa
- Department of Dermatology, Stanford School of Medicine, Stanford, CA, USA
- Department of Pathology, Stanford School of Medicine, Stanford, CA, USA
| | - Justin M Ko
- Department of Dermatology, Stanford School of Medicine, Stanford, CA, USA
| | | |
Collapse
|
3
|
Tilp M. Commentary on "Multiscale hamstring muscle adaptations following 9 weeks of eccentric training". JOURNAL OF SPORT AND HEALTH SCIENCE 2024; 14:101002. [PMID: 39490653 PMCID: PMC11863314 DOI: 10.1016/j.jshs.2024.101002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2024] [Accepted: 08/26/2024] [Indexed: 11/05/2024]
Affiliation(s)
- Markus Tilp
- Department of Human Movement Science, Sport and Health, University of Graz, 8043 Graz, Austria.
| |
Collapse
|
4
|
Andrews MH, S AP, Gurchiek RD, Pincheira PA, Chaudhari AS, Hodges PW, Lichtwark GA, Delp SL. Multiscale hamstring muscle adaptations following 9 weeks of eccentric training. JOURNAL OF SPORT AND HEALTH SCIENCE 2024; 14:100996. [PMID: 39461588 PMCID: PMC11863337 DOI: 10.1016/j.jshs.2024.100996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 06/13/2024] [Accepted: 06/28/2024] [Indexed: 10/29/2024]
Abstract
BACKGROUND Eccentric training, such as Nordic hamstring exercise (NHE) training, is commonly used as a preventive measure for hamstring strains. Eccentric training is believed to induce lengthening of muscle fascicles and to be associated with the addition of sarcomeres in series within muscle fibers. However, the difficulty in measuring sarcomere adaptation in human muscles has severely limited information about the precise mechanisms of adaptation. This study addressed this limitation by measuring the multiscale hamstring muscle adaptations in response to 9 weeks of NHE training and 3 weeks of detraining. METHODS Twelve participants completed 9 weeks of supervised NHE training, followed by a 3-week detraining period. We assessed biceps femoris long-head (BFlh) muscle fascicle length, sarcomere length, and serial sarcomere number in the central and distal regions of the muscle. Additionally, we measured muscle volume and eccentric strength at baseline, post-training, and post-detraining. RESULTS NHE training over 9 weeks induced significant architectural and strength adaptations in the BFlh muscle. Fascicle length increased by 19% in the central muscle region and 33% in the distal muscle region. NHE also induced increases in serial sarcomere number (25% in the central region and 49% in the distal region). BFlh muscle volume increased by 8%, and knee flexion strength increased by 40% with training. Following 3 weeks of detraining, fascicle length decreased by 12% in the central region and 16% in the distal region along with reductions in serial sarcomere number. CONCLUSION Nine weeks of NHE training produced substantial, region-specific increases in BFlh muscle fascicle length, muscle volume, and force generation. The direct measurement of sarcomere lengths revealed that the increased fascicle length was accompanied by the addition of sarcomeres in series within the muscle fascicles.
Collapse
Affiliation(s)
- Max H Andrews
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD 4072, Australia; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Anoosha Pai S
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Reed D Gurchiek
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
| | - Patricio A Pincheira
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD 4072, Australia; School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, QLD 4072, Australia; School of Health and Medical Sciences, The University of Southern Queensland, Ipswich, QLD 4305, Australia
| | | | - Paul W Hodges
- School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glen A Lichtwark
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD 4072, Australia; School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Scott L Delp
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|
5
|
Birkbeck MG, Heskamp L, Schofield IS, Hall J, Sayer AA, Whittaker RG, Blamire AM. Whole Muscle and Single Motor Unit Twitch Profiles in a Healthy Adult Cohort Assessed With Phase Contrast Motor Unit MRI (PC-MUMRI). J Magn Reson Imaging 2024; 60:205-217. [PMID: 37776094 DOI: 10.1002/jmri.29028] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 10/01/2023] Open
Abstract
BACKGROUND Motor units (MUs) control the contraction of muscles and degenerate with age. It is therefore of interest to measure whole muscle and MU twitch profiles in aging skeletal muscle. PURPOSE Apply phase contrast MU MRI (PC-MUMRI) in a cohort of healthy adults to measure whole anterior compartment, individual muscles, and single MU twitch profiles in the calf. Assess the effect of age and sex on contraction and relaxation times. STUDY TYPE Prospective cross-sectional study. SUBJECTS Sixty-one healthy participants (N = 32 male; age 55 ± 16 years [range: 26-82]). FIELD STRENGTH/SEQUENCES 3 T, velocity encoded gradient echo and single shot spin echo pulsed gradient spin echo, echo-planar imaging. ASSESSMENT Anterior shin compartment (N = 47), individual muscle (tibialis anterior, extensor digitorum longus, peroneus longus; N = 47) and single MU (N = 34) twitch profiles were extracted from the data to calculate contraction and relaxation times. STATISTICAL TESTS Multivariable linear regression to investigate relationships between age, sex and contraction and relaxation times of the whole anterior compartment. Pearson correlation to investigate relationships between age and contraction and relaxation times of individual muscles and single MUs. A P value <0.05 was considered statistically significant. RESULTS Age and sex predicted significantly increased contraction and relaxation time for the anterior compartment. Females had significantly longer contraction times than males (females 86 ± 8 msec, males 80 ± 9 msec). Relaxation times were longer, not significant (females 204 ± 36 msec, males 188 ± 34 msec, P = 0.151). Contraction and relaxation times of single MUs showed no change with age (P = 0.462, P = 0.534, respectively). DATE CONCLUSION Older participants had significantly longer contraction and relaxation times of the whole anterior compartment compared to younger participants. Females had longer contraction and relaxation times than males, significant for contraction time. EVIDENCE LEVEL 2 TECHNICAL EFFICACY: Stage 1.
Collapse
Affiliation(s)
- Matthew G Birkbeck
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University, Newcastle upon Tyne, UK
- Northern Medical Physics and Clinical Engineering, Freeman Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Linda Heskamp
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Ian S Schofield
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Julie Hall
- Department of Neuroradiology, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle University, Newcastle upon Tyne, UK
| | - Avan A Sayer
- NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University, Newcastle upon Tyne, UK
| | - Roger G Whittaker
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Andrew M Blamire
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| |
Collapse
|
6
|
Wohlgemuth RP, Kulkarni VA, Villalba M, Davids JR, Smith LR. Collagen architecture and biomechanics of gracilis and adductor longus muscles from children with cerebral palsy. J Physiol 2024; 602:3489-3504. [PMID: 39008710 PMCID: PMC11849552 DOI: 10.1113/jp285988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 06/05/2024] [Indexed: 07/17/2024] Open
Abstract
Cerebral palsy (CP) describes some upper motoneuron disorders due to non-progressive disturbances occurring in the developing brain that cause progressive changes to muscle. While longer sarcomeres increase muscle stiffness in patients with CP compared to typically developing (TD) patients, changes in extracellular matrix (ECM) architecture can increase stiffness. Our goal was to investigate how changes in muscle and ECM architecture impact muscle stiffness, gait and joint function in CP. Gracilis and adductor longus biopsies were collected from children with CP undergoing tendon lengthening surgery for hamstring and hip adduction contractures, respectively. Gracilis biopsies were collected from TD patients undergoing anterior cruciate ligament reconstruction surgery with hamstring autograft. Muscle mechanical testing, two-photon imaging and hydroxyproline assay were performed on biopsies. Corresponding data were compared to radiographic hip displacement in CP adductors (CPA), gait kinematics in CP hamstrings (CPH), and joint range of motion in CPA and CPH. We found at matched sarcomere lengths muscle stiffness and collagen architecture were similar between TD and CP hamstrings. However, CPH stiffness (R2 = 0.1973), collagen content (R2 = 0.5099) and cross-linking (R2 = 0.3233) were correlated to decreased knee range of motion. Additionally, we observed collagen fibres within the muscle ECM increase alignment during muscular stretching. These data demonstrate that while ECM architecture is similar between TD and CP hamstrings, collagen fibres biomechanics are sensitive to muscle strain and may be altered at longer in vivo sarcomere lengths in CP muscle. Future studies could evaluate the impact of ECM architecture on TD and CP muscle stiffness across in vivo operating ranges. KEY POINTS: At matched sarcomere lengths, gracilis muscle mechanics and collagen architecture are similar in TD patients and patients with CP. In both TD and CP muscles, collagen fibres dynamically increase their alignment during muscle stretching. Aspects of muscle mechanics and collagen architecture are predictive of in vivo knee joint motion and radiographic hip displacement in patients with CP. Longer sarcomere lengths in CP muscle in vivo may alter collagen architecture and biomechanics to drive deficits in joint mobility and gait function.
Collapse
Affiliation(s)
- Ross P Wohlgemuth
- Department of Neurobiology, Physiology, & Behavior, University of California Davis, Davis, CA, USA
| | - Vedant A Kulkarni
- Department of Orthopaedic Surgery, Shriners Children's Northern California, Sacramento, CA, USA
| | - Marie Villalba
- Department of Orthopaedic Surgery, Shriners Children's Northern California, Sacramento, CA, USA
| | - Jon R Davids
- Department of Orthopaedic Surgery, Shriners Children's Northern California, Sacramento, CA, USA
| | - Lucas R Smith
- Department of Neurobiology, Physiology, & Behavior, University of California Davis, Davis, CA, USA
- Department of Physical Medicine and Rehabilitation, University of California Davis, Davis, CA, USA
| |
Collapse
|
7
|
Waldvogel J, Freyler K, Ritzmann R, Gollhofer A. Energy transfer in reactive movements as a function of individual stretch load. Front Physiol 2023; 14:1265443. [PMID: 38098807 PMCID: PMC10720888 DOI: 10.3389/fphys.2023.1265443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 11/13/2023] [Indexed: 12/17/2023] Open
Abstract
Background: By directly recording electromyographic activity profiles and muscle-tendon interaction, this study aimed to elucidate the mechanisms why well-trained track and field athletes (experts) are able to outperform untrained individuals without former systematic experience in reactive jump training (novices). In particular, reactive power output and the elastic recoil properties of the muscle-tendon unit (MTU) were of special interest. For this purpose, stiffness regulation on muscle and joint level, energy management in terms of storing or dissipating elastic energy were compared between experts and novices during various stretch loads. Methods: Experts were compared with novices during reactive drop jumps (DJs) from drop heights ranging between 25 and 61 cm. Delta kinetic energy (Ekin) was calculated as the difference between the Ekin at take-off and ground contact (GC) to determine energy management. By recording electromyography of the lower limb muscles, in vivo fascicle dynamics (gastrocnemius medialis) and by combining kinematics and kinetics in a 3D inverse dynamics approach to compute ankle and knee joint kinetics, this study aimed to compare reactive jump performance, the neuromuscular activity and muscle-tendon interaction between experts and novices among the tested stretch loads. Results: Experts demonstrated significantly higher power output during DJs. Among all drop heights experts realized higher delta Ekin compared to novices. Consequently, higher reactive jump performance shown for experts was characterized by shorter GC time (GCT), higher jump heights and higher neuromuscular activity before and during the GC phase compared to novices. Concomitantly, experts were able to realize highest leg stiffness and delta Ekin in the lowest stretch load; however, both groups compensated the highest stretch load by prolonged GCT and greater joint flexion. On muscle level, experts work quasi-isometrically in the highest stretch load, while in novices GM fascicles were forcefully stretched. Conclusion: Group-specific stiffness regulation and elastic recoil properties are primarily influenced by the neuromuscular system. Due to their higher neuromuscular activity prior and during the GC phase, experts demonstrate higher force generating capacity. A functionally stiffer myotendinous system through enhanced neuromuscular input enables the experts loading their elastic recoil system more efficiently, thus realizing higher reactive power output and allowing a higher amount of energy storage and return. This mechanism is regulated in a stretch load dependent manner.
Collapse
Affiliation(s)
- Janice Waldvogel
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | | | | | | |
Collapse
|
8
|
Grinspan GA, Fernandes de Oliveira L, Brandao MC, Pomi A, Benech N. Load sharing between synergistic muscles characterized by a ligand-binding approach and elastography. Sci Rep 2023; 13:18267. [PMID: 37880279 PMCID: PMC10600237 DOI: 10.1038/s41598-023-45037-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/14/2023] [Indexed: 10/27/2023] Open
Abstract
The skeletal muscle contraction is determined by cross-bridge formation between the myosin heads and the actin active sites. When the muscle contracts, it shortens, increasing its longitudinal shear elastic modulus ([Formula: see text]). Structurally, skeletal muscle can be considered analogous to the molecular receptors that form receptor-ligand complexes and exhibit specific ligand-binding dynamics. In this context, this work aims to apply elastography and the ligand-binding framework to approach the possible intrinsic mechanisms behind muscle synergism. Based on the short-range stiffness principle and the acoustic-elasticity theory, we define the coefficient [Formula: see text], which is directly related to the fraction saturation of molecular receptors and links the relative longitudinal deformation of the muscle to its [Formula: see text]. We show that such a coefficient can be obtained directly from [Formula: see text] estimates, thus calculating it for the biceps brachii, brachioradialis, and brachialis muscles during isometric elbow flexion torque (τ) ramps. The resulting [Formula: see text] curves were analyzed by conventional characterization methods of receptor-ligand systems to study the dynamical behavior of each muscle. The results showed that, depending on muscle, [Formula: see text] exhibits typical ligand-binding dynamics during joint torque production. Therefore, the above indicates that these different behaviors describe the longitudinal shortening pattern of each muscle during load sharing. As a plausible interpretation, we suggested that this could be related to the binding kinetics of the cross-bridges during their synergistic action as torque increases. Likewise, it shows that elastography could be useful to assess contractile processes at different scales related to the change in the mechanical properties of skeletal muscle.
Collapse
Affiliation(s)
- Gustavo A Grinspan
- Sección Biofísica y Biología de Sistemas, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay.
- Laboratorio de Acústica Ultrasonora, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay.
| | - Liliam Fernandes de Oliveira
- Laboratório de Análise do Movimento e Fisiologia do Exercício, Programa de Engenharia Biomédica, Universidade Federal do Rio de Janeiro, Av. Horácio Macedo 2030, Rio de Janeiro, 21941-590, Brazil
| | - Maria Clara Brandao
- Laboratório de Análise do Movimento e Fisiologia do Exercício, Programa de Engenharia Biomédica, Universidade Federal do Rio de Janeiro, Av. Horácio Macedo 2030, Rio de Janeiro, 21941-590, Brazil
| | - Andrés Pomi
- Sección Biofísica y Biología de Sistemas, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Nicolás Benech
- Laboratorio de Acústica Ultrasonora, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| |
Collapse
|
9
|
Gogeascoechea A, Ornelas-Kobayashi R, Yavuz US, Sartori M. Characterization of Motor Unit Firing and Twitch Properties for Decoding Musculoskeletal Force in the Human Ankle Joint In Vivo. IEEE Trans Neural Syst Rehabil Eng 2023; 31:4040-4050. [PMID: 37756177 DOI: 10.1109/tnsre.2023.3319959] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Understanding how motor units (MUs) contribute to skeletal mechanical force is crucial for unraveling the underlying mechanism of human movement. Alterations in MU firing, contractile and force-generating properties emerge in response to physical training, aging or injury. However, how changes in MU firing and twitch properties dictate skeletal muscle force generation in healthy and impaired individuals remains an open question. In this work, we present a MU-specific approach to identify firing and twitch properties of MU samples and employ them to decode musculoskeletal function in vivo. First, MU firing events were decomposed offline from high-density electromyography (HD-EMG) of six lower leg muscles involved in ankle plantar-dorsi flexion. We characterized their twitch responses based on the statistical distributions of their firing properties and employed them to compute MU-specific activation dynamics. Subsequently, we decoded ankle joint moments by linking our framework to a subject-specific musculoskeletal model. We validated our approach at different ankle positions and levels of activation and compared it with traditional EMG-driven models. Our proposed MU-specific formulation achieves higher generalization across conditions than the EMG-driven models, with significantly lower coefficients of variation in torque predictions. Furthermore, our approach shows distinct neural strategies across a large repertoire of contractile conditions in different muscles. Our proposed approach may open new avenues for characterizing the relationship between MU firing and twitch properties and their influence on force capacity. This can facilitate the development of targeted rehabilitation strategies tailored to individuals with specific neuromuscular conditions.
Collapse
|
10
|
Saidi S, Shtrahman M. Evaluation of compact pulsed lasers for two-photon microscopy using a simple method for measuring two-photon excitation efficiency. NEUROPHOTONICS 2023; 10:044303. [PMID: 38076726 PMCID: PMC10704185 DOI: 10.1117/1.nph.10.4.044303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/26/2023] [Accepted: 10/17/2023] [Indexed: 02/12/2024]
Abstract
Significance Two-photon (2p) microscopy has historically relied on titanium sapphire pulsed lasers that are expensive and have a large footprint. Recently, several manufacturers have developed less expensive compact pulsed lasers optimized for 2p excitation of green fluorophores. However, quantitative evaluation of their quality is lacking. Aim We describe a simple approach to systematically evaluate 2p excitation efficiency, an empiric measure of the quality of a pulsed laser and its ability to elicit 2p induced fluorescence. Approach By measuring pulse width, repetition rate, and fluorescence output, we calculated a measure of 2p excitation efficiency η , which we compared for four commercially available compact pulsed lasers in the 920 to 930 nm wavelength range. Results 2p excitation efficiency varied substantially among tested lasers. The Coherent Axon exhibited the best 2p excitation efficiency (1.09 ± 0.03 ), exceeding that of a titanium sapphire reference laser (defined to have efficiency = 1). However, its measured fluorescence was modest due to its long pulse width. Of the compact lasers, the Toptica Femtofiber Ultra exhibited the best combination of measured fluorescence (0.75 ± 0.01 ) and 2p excitation efficiency (0.86 ± 0.01 ). Conclusions We describe a simple method that both laser developers and end users can use to benchmark the 2p excitation efficiency of lasers used for 2p microscopy.
Collapse
Affiliation(s)
- Samir Saidi
- University of California, San Diego, Shu Chien-Gene Lay Department of Bioengineering, La Jolla, California, United States
| | - Matthew Shtrahman
- University of California, San Diego, Department of Neurosciences, La Jolla, California, United States
| |
Collapse
|
11
|
Mahdian ZS, Wang H, Refai MIM, Durandau G, Sartori M, MacLean MK. Tapping Into Skeletal Muscle Biomechanics for Design and Control of Lower Limb Exoskeletons: A Narrative Review. J Appl Biomech 2023; 39:318-333. [PMID: 37751903 DOI: 10.1123/jab.2023-0046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/11/2023] [Accepted: 08/18/2023] [Indexed: 09/28/2023]
Abstract
Lower limb exoskeletons and exosuits ("exos") are traditionally designed with a strong focus on mechatronics and actuation, whereas the "human side" is often disregarded or minimally modeled. Muscle biomechanics principles and skeletal muscle response to robot-delivered loads should be incorporated in design/control of exos. In this narrative review, we summarize the advances in literature with respect to the fusion of muscle biomechanics and lower limb exoskeletons. We report methods to measure muscle biomechanics directly and indirectly and summarize the studies that have incorporated muscle measures for improved design and control of intuitive lower limb exos. Finally, we delve into articles that have studied how the human-exo interaction influences muscle biomechanics during locomotion. To support neurorehabilitation and facilitate everyday use of wearable assistive technologies, we believe that future studies should investigate and predict how exoskeleton assistance strategies would structurally remodel skeletal muscle over time. Real-time mapping of the neuromechanical origin and generation of muscle force resulting in joint torques should be combined with musculoskeletal models to address time-varying parameters such as adaptation to exos and fatigue. Development of smarter predictive controllers that steer rather than assist biological components could result in a synchronized human-machine system that optimizes the biological and electromechanical performance of the combined system.
Collapse
Affiliation(s)
- Zahra S Mahdian
- Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands
| | - Huawei Wang
- Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands
| | | | - Guillaume Durandau
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada
| | - Massimo Sartori
- Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands
| | - Mhairi K MacLean
- Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands
| |
Collapse
|
12
|
Blemker SS. In vivo imaging of skeletal muscle form and function: 50 years of insight. J Biomech 2023; 158:111745. [PMID: 37579605 DOI: 10.1016/j.jbiomech.2023.111745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/22/2023] [Accepted: 07/27/2023] [Indexed: 08/16/2023]
Abstract
Skeletal muscle form and function has fascinated scientists for centuries. Our understanding of muscle function has long been driven by advancements in imaging techniques. For example, the sliding filament theory of muscle, which is now widely leveraged in biomechanics research, stemmed from observations made possible by scanning electron microscopy. Over the last 50 years, advancing in medical imaging, combined with ingenuity and creativity of biomechanists, have provide a wealth of new and important insights into in vivo human muscle function. Incorporation of in vivo imaging has also advanced computational modeling and allowed our research to have an impact in many clinical populations. While this review does not provide a comprehensive or meta-analysis of the all the in vivo muscle imaging work over the last five decades, it provides a narrative about the past, present, and future of in vivo muscle imaging.
Collapse
Affiliation(s)
- Silvia S Blemker
- Departments of Biomedical Engineering, Mechanical & Aerospace Engineering, Ophthalmology, and Orthopedic Surgery, University of Virginia, Charlottesville, VA, United States; Springbok Analytics, Charlottesville, VA, United States
| |
Collapse
|
13
|
Markus MA, Ferrari DP, Alves F, Ramos-Gomes F. Effect of tissue fixation on the optical properties of structural components assessed by non-linear microscopy imaging. BIOMEDICAL OPTICS EXPRESS 2023; 14:3988-4002. [PMID: 37799688 PMCID: PMC10549744 DOI: 10.1364/boe.488453] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 10/07/2023]
Abstract
Fixation methods such as formalin are commonly used for the preservation of tissue with the aim of keeping their structure as close as possible to the native condition. However, fixatives chemically interact with tissue molecules, such as collagen in the extracellular matrix (ECM) or myosin, and may thus modify their structure. Taking advantage of the second- and third-harmonic generation (SHG and THG) emission capabilities of such components, we used nonlinear two-photon microscopy (NL2PM) to evaluate the effect that preservation methods, such as chemical fixatives, have on the nonlinear capabilities of protein components within mouse tissues. Our results show that depending on the preservation technique used, the nonlinear capabilities of collagen, lipid droplets and myosin microarchitecture are strongly affected. Parameters of collagen fibers, such as density and branch points, especially in collagen-sparse regions, e.g., in kidneys, were found to be altered upon formalin fixation. Moreover, cryo-freezing drastically reduced SHG signals from myosin. Our findings provide valuable information to select the best tissue fixation method for visualization and quantification of structural proteins, such as collagen and myosin by advanced NL2PM imaging techniques. This may advance the interpretation of the role these proteins play in disease.
Collapse
Affiliation(s)
- M. Andrea Markus
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Daniele P. Ferrari
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Frauke Alves
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
- Clinic of Haematology and Medical Oncology, Institute of Interventional and Diagnostic Radiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Fernanda Ramos-Gomes
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| |
Collapse
|
14
|
Raikova R, Krutki P, Celichowski J. Skeletal muscle models composed of motor units: A review. J Electromyogr Kinesiol 2023; 70:102774. [PMID: 37099899 DOI: 10.1016/j.jelekin.2023.102774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 04/06/2023] [Accepted: 04/09/2023] [Indexed: 04/28/2023] Open
Abstract
The mathematical muscle models should include several aspects of muscle structure and physiology. First, muscle force is the sum of forces of multiple motor units (MUs), which have different contractile properties and play different roles in generating muscle force. Second, whole muscle activity is an effect of net excitatory inputs to a pool of motoneurons innervating the muscle, which have different excitability, influencing MU recruitment. In this review, we compare various methods for modeling MU twitch and tetanic forces and then discuss muscle models composed of different MU types and number. We first present four different analytical functions used for twitch modeling and show limitations related to the number of twitch describing parameters. We also show that a nonlinear summation of twitches should be considered in modeling tetanic contractions. We then compare different muscle models, most of which are variations of Fuglevand's model, adopting a common drive hypothesis and the size principle. We pay attention to integrating previously developed models into a consensus model based on physiological data from in vivo experiments on the rat medial gastrocnemius muscle and its respective motoneurons. Finally, we discuss the shortcomings of existing models and potential applications for studying MU synchronization, potentiation, and fatigue.
Collapse
Affiliation(s)
- Rositsa Raikova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Bulgaria.
| | - Piotr Krutki
- Department of Neurobiology, Poznan University of Physical Education, Poland
| | - Jan Celichowski
- Department of Neurobiology, Poznan University of Physical Education, Poland
| |
Collapse
|
15
|
Malakoutian M, Sanchez CA, Brown SHM, Street J, Fels S, Oxland TR. Biomechanical Properties of Paraspinal Muscles Influence Spinal Loading—A Musculoskeletal Simulation Study. Front Bioeng Biotechnol 2022; 10:852201. [PMID: 35721854 PMCID: PMC9201424 DOI: 10.3389/fbioe.2022.852201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/15/2022] [Indexed: 11/13/2022] Open
Abstract
Paraspinal muscles are vital to the functioning of the spine. Changes in muscle physiological cross-sectional area significantly affect spinal loading, but the importance of other muscle biomechanical properties remains unclear. This study explored the changes in spinal loading due to variation in five muscle biomechanical properties: passive stiffness, slack sarcomere length (SSL), in situ sarcomere length, specific tension, and pennation angle. An enhanced version of a musculoskeletal simulation model of the thoracolumbar spine with 210 muscle fascicles was used for this study and its predictions were validated for several tasks and multiple postures. Ranges of physiologically realistic values were selected for all five muscle parameters and their influence on L4-L5 intradiscal pressure (IDP) was investigated in standing and 36° flexion. We observed large changes in IDP due to changes in passive stiffness, SSL, in situ sarcomere length, and specific tension, often with interesting interplays between the parameters. For example, for upright standing, a change in stiffness value from one tenth to 10 times the baseline value increased the IDP only by 91% for the baseline model but by 945% when SSL was 0.4 μm shorter. Shorter SSL values and higher stiffnesses led to the largest increases in IDP. More changes were evident in flexion, as sarcomere lengths were longer in that posture and thus the passive curve is more influential. Our results highlight the importance of the muscle force-length curve and the parameters associated with it and motivate further experimental studies on in vivo measurement of those properties.
Collapse
Affiliation(s)
- Masoud Malakoutian
- Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada
- ICORD, University of British Columbia, Vancouver, BC, Canada
| | - C. Antonio Sanchez
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Stephen H. M. Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - John Street
- ICORD, University of British Columbia, Vancouver, BC, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada
| | - Sidney Fels
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Thomas R. Oxland
- Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada
- ICORD, University of British Columbia, Vancouver, BC, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Thomas R. Oxland,
| |
Collapse
|
16
|
Stäudle B, Seynnes O, Laps G, Brüggemann GP, Albracht K. Altered Gastrocnemius Contractile Behavior in Former Achilles Tendon Rupture Patients During Walking. Front Physiol 2022; 13:792576. [PMID: 35299659 PMCID: PMC8921480 DOI: 10.3389/fphys.2022.792576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 02/01/2022] [Indexed: 11/17/2022] Open
Abstract
Achilles tendon rupture (ATR) remains associated with functional limitations years after injury. Architectural remodeling of the gastrocnemius medialis (GM) muscle is typically observed in the affected leg and may compensate force deficits caused by a longer tendon. Yet patients seem to retain functional limitations during-low-force-walking gait. To explore the potential limits imposed by the remodeled GM muscle-tendon unit (MTU) on walking gait, we examined the contractile behavior of muscle fascicles during the stance phase. In a cross-sectional design, we studied nine former patients (males; age: 45 ± 9 years; height: 180 ± 7 cm; weight: 83 ± 6 kg) with a history of complete unilateral ATR, approximately 4 years post-surgery. Using ultrasonography, GM tendon morphology, muscle architecture at rest, and fascicular behavior were assessed during walking at 1.5 m⋅s-1 on a treadmill. Walking patterns were recorded with a motion capture system. The unaffected leg served as control. Lower limbs kinematics were largely similar between legs during walking. Typical features of ATR-related MTU remodeling were observed during the stance sub-phases corresponding to series elastic element (SEE) lengthening (energy storage) and SEE shortening (energy release), with shorter GM fascicles (36 and 36%, respectively) and greater pennation angles (8° and 12°, respectively). However, relative to the optimal fascicle length for force production, fascicles operated at comparable length in both legs. Similarly, when expressed relative to optimal fascicle length, fascicle contraction velocity was not different between sides, except at the time-point of peak series elastic element (SEE) length, where it was 39 ± 49% lower in the affected leg. Concomitantly, fascicles rotation during contraction was greater in the affected leg during the whole stance-phase, and architectural gear ratios (AGR) was larger during SEE lengthening. Under the present testing conditions, former ATR patients had recovered a relatively symmetrical walking gait pattern. Differences in seen AGR seem to accommodate the profound changes in MTU architecture, limiting the required fascicle shortening velocity. Overall, the contractile behavior of the GM fascicles does not restrict length- or velocity-dependent force potentials during this locomotor task.
Collapse
Affiliation(s)
- Benjamin Stäudle
- Faculty of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany
- Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany
| | - Olivier Seynnes
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Guido Laps
- Orthopädie am Gürzenich, Cologne, Germany
| | - Gert-Peter Brüggemann
- Institute of Biomechanics and Orthopedics, German Sport University Cologne, Cologne, Germany
| | - Kirsten Albracht
- Faculty of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany
- Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany
| |
Collapse
|
17
|
Adkins AN, Fong RM, Dewald JPA, Murray WM. Variability of in vivo Sarcomere Length Measures in the Upper Limb Obtained With Second Harmonic Generation Microendoscopy. Front Physiol 2022; 12:817334. [PMID: 35211028 PMCID: PMC8861439 DOI: 10.3389/fphys.2021.817334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
The lengths of a muscle’s sarcomeres are a primary determinant of its ability to contract and produce force. In addition, sarcomere length is a critical parameter that is required to make meaningful comparisons of both the force-generating and excursion capacities of different muscles. Until recently, in vivo sarcomere length data have been limited to invasive or intraoperative measurement techniques. With the advent of second harmonic generation microendoscopy, minimally invasive measures of sarcomere length can be made for the first time. This imaging technique expands our ability to study muscle adaptation due to changes in stimulus, use, or disease. However, due to past inability to measure sarcomeres outside of surgery or biopsy, little is known about the natural, anatomical variability in sarcomere length in living human subjects. To develop robust experimental protocols that ensure data provide accurate representations of a muscle’s sarcomere lengths, we sought to quantify experimental uncertainty associated with in vivo measures of sarcomere lengths. Specifically, we assessed the variability in sarcomere length measured (1) within a single image, along a muscle fiber, (2) across images captured within a single trial, across trials, and across days, as well as (3) across locations in the muscle using second harmonic generation in two upper limb muscles with different muscle architectures, functions, and sizes. Across all of our measures of variability we estimate that the magnitude of the uncertainty for in vivo sarcomere length is on the order of ∼0.25 μm. In the two upper limb muscles studied we found larger variability in sarcomere lengths within a single insertion than across locations. We also developed custom code to make measures of sarcomere length variability across a single fiber and determined that this codes’ accuracy is an order of magnitude smaller than our measurement uncertainty due to sarcomere variability. Together, our findings provide guidance for the development of robust experimental design and analysis of in vivo sarcomere lengths in the upper limb.
Collapse
Affiliation(s)
- Amy N Adkins
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States.,Shirley Ryan AbilityLab, Chicago, IL, United States.,Edward Hines, Jr. VA Hospital, Hines, IL, United States
| | - Ryan M Fong
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States.,Shirley Ryan AbilityLab, Chicago, IL, United States
| | - Julius P A Dewald
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States.,Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.,Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Wendy M Murray
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States.,Shirley Ryan AbilityLab, Chicago, IL, United States.,Edward Hines, Jr. VA Hospital, Hines, IL, United States.,Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.,Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| |
Collapse
|
18
|
Pincheira PA, Boswell MA, Franchi MV, Delp SL, Lichtwark GA. Biceps femoris long head sarcomere and fascicle length adaptations after 3 weeks of eccentric exercise training. JOURNAL OF SPORT AND HEALTH SCIENCE 2022; 11:43-49. [PMID: 34509714 PMCID: PMC8847943 DOI: 10.1016/j.jshs.2021.09.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/25/2021] [Accepted: 08/05/2021] [Indexed: 05/02/2023]
Abstract
BACKGROUND Eccentric exercise increases muscle fascicle lengths; however, the mechanisms behind this adaptation are still unknown. This study aimed to determine whether biceps femoris long head (BFlh) fascicle length increases in response to 3 weeks of eccentric exercise training are the result of an in-series addition of sarcomeres within the muscle fibers. METHODS Ten recreationally active participants (age = 27 ± 3 years; mass = 70 ± 14 kg; height = 174 ± 9 cm; mean ± SD) completed 3 weeks of Nordic hamstring exercise (NHE) training on a custom exercise device that was instrumented with load cells. We collected in vivo sarcomere and muscle fascicle images of the BFlh in 2 regions (central and distal) by using microendoscopy and 3 dimension ultrasonography. We then estimated sarcomere length, sarcomere number, and fascicle length before and after the training intervention. RESULTS Eccentric knee flexion strength increased after the training (15%; p < 0.001; ηp2 = 0.75). Further, we found a significant increase in fascicle length (21%; p < 0.001; ηp2 = 0.81) and sarcomere length (17%; p < 0.001; ηp2 = 0.90) in the distal but not in the central portion of the muscle. The estimated number of sarcomeres in series did not change in either region. CONCLUSION Fascicle length adaptations appear to be heterogeneous in the BFlh in response to 3 weeks of NHE training. An increase in sarcomere length, rather than the addition of sarcomeres in series, appears to underlie increases in fascicle length in the distal region of the BFlh. The mechanism driving regional increases in fascicle and sarcomere length remains unknown, but we speculate that it may be driven by regional changes in the passive tension of muscle or connective tissue adaptations.
Collapse
Affiliation(s)
- Patricio A Pincheira
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Melissa A Boswell
- Department of Bioengineering and Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Martino V Franchi
- Department of Biomedical Sciences, University of Padova, Padova 35122, Italy
| | - Scott L Delp
- Department of Bioengineering and Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Glen A Lichtwark
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| |
Collapse
|
19
|
In vivo non-invasive near-infrared spectroscopy distinguishes normal, post-stroke, and botulinum toxin treated human muscles. Sci Rep 2021; 11:17631. [PMID: 34480037 PMCID: PMC8417034 DOI: 10.1038/s41598-021-96547-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/12/2021] [Indexed: 12/22/2022] Open
Abstract
In post-stroke hemiparesis, neural impairment alters muscle control, causing abnormal movement and posture in the affected limbs. A decrease in voluntary use of the paretic arm and flexed posture during rest also induce secondary tissue transformation in the upper limb muscles. To obtain a specific, accurate, and reproducible marker of the current biological status of muscles, we collected visible (VIS) and short-wave Infrared (SWIR) reflectance spectra in vivo using a portable spectroradiometer (350–2500 nm), which provided the spectral fingerprints of the elbow flexors and extensors. We compared the spectra for the affected and unaffected sides in 23 patients with post-stroke hemiparesis (25–87 years, 8 women) and eight healthy controls (33–87 years, 5 women). In eight patients, spectra were collected before and after botulinum toxin injection. Spectra underwent off-line preprocessing, principal component analysis, and partial least-squares discriminant analysis. Spectral fingerprints discriminated the muscle (biceps vs. triceps), neurological condition (normal vs. affected vs. unaffected), and effect of botulinum toxin treatment (before vs. 30 to 40 days vs. 110 to 120 days after injection). VIS-SWIR spectroscopy proved valuable for non-invasive assessment of optical properties in muscles, enabled more comprehensive evaluation of hemiparetic muscles, and provided optimal monitoring of the effectiveness of medication.
Collapse
|
20
|
Kong JS, Huang X, Choi Y, Yi H, Kang J, Kim S, Kim J, Lee H, Rim YA, Ju JH, Chung WK, Woolf CJ, Jang J, Cho D. Promoting Long-Term Cultivation of Motor Neurons for 3D Neuromuscular Junction Formation of 3D In Vitro Using Central-Nervous-Tissue-Derived Bioink. Adv Healthc Mater 2021; 10:e2100581. [PMID: 34363335 DOI: 10.1002/adhm.202100581] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/16/2021] [Indexed: 12/14/2022]
Abstract
3D cell printing technology is in the spotlight for producing 3D tissue or organ constructs useful for various medical applications. In printing of neuromuscular tissue, a bioink satisfying all the requirements is a challenging issue. Gel integrity and motor neuron activity are two major characters because a harmonious combination of extracellular materials essential to motor neuron activity consists of disadvantages in mechanical properties. Here, a method for fabrication of 3D neuromuscular tissue is presented using a porcine central nervous system tissue decellularized extracellular matrix (CNSdECM) bioink. CNSdECM retains CNS tissue-specific extracellular molecules, provides rheological properties crucial for extrusion-based 3D cell printing, and reveals positive effects on the growth and maturity of axons of motor neurons compared with Matrigel. It also allows long-term cultivation of human-induced-pluripotent-stem-cell-derived lower motor neurons and sufficiently supports their cellular behavior to carry motor signals to muscle fibers. CNSdECM bioink holds great promise for producing a tissue-engineered motor system using 3D cell printing.
Collapse
Affiliation(s)
- Jeong Sik Kong
- School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
| | - Xuan Huang
- FM Kirby Neurobiology Center Boston Children's Hospital and Department of Neurobiology Harvard Medical School Boston MA 02115 USA
| | - Yeong‐Jin Choi
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Materials Processing Innovation Research Division Korea Institute of Materials Science (KIMS) 797 10 Changwondaero, Kyungnam Changwon 51508 Republic of Korea
| | - Hee‐Gyeong Yi
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Department of Rural and Biosystems Engineering College of Agriculture and Life Sciences Chonnam National University Gwangju 61186 Republic of Korea
| | - Junsu Kang
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
| | - Sejin Kim
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
| | - Jongmin Kim
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
| | - Hyungseok Lee
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Department of Mechanical and Biomedical Engineering Kangwon National University (KNU) 1 Gangwondaehak‐gil, Seoksa‐dong Chuncheon‐si Gangwon‐do 24341 Republic of Korea
- Interdisciplinary Program in Biohealth‐Machinery Convergence Engineering Kangwon National University (KNU) Chuncheon 24341 Republic of Korea
| | - Yeri Alice Rim
- Catholic iPSC Research Center, College of Medicine The Catholic University of Korea Seoul 137‐701 Republic of Korea
| | - Ji Hyeon Ju
- Catholic iPSC Research Center, College of Medicine The Catholic University of Korea Seoul 137‐701 Republic of Korea
| | - Wan Kyun Chung
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
| | - Clifford J. Woolf
- FM Kirby Neurobiology Center Boston Children's Hospital and Department of Neurobiology Harvard Medical School Boston MA 02115 USA
| | - Jinah Jang
- School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Department of Convergence IT Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Institute for Convergence Research and Education in Advanced Technology Yonsei University Seoul 03722 Republic of Korea
| | - Dong‐Woo Cho
- School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam‐ro, Nam‐gu Pohang Kyungbuk 37673 Republic of Korea
- Institute for Convergence Research and Education in Advanced Technology Yonsei University Seoul 03722 Republic of Korea
| |
Collapse
|
21
|
Moltubakk MM, Villars FO, Magulas MM, Magnusson SP, Seynnes OR, Bojsen-Møller J. Altered Triceps Surae Muscle-Tendon Unit Properties after 6 Months of Static Stretching. Med Sci Sports Exerc 2021; 53:1975-1986. [PMID: 34398062 DOI: 10.1249/mss.0000000000002671] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION This study examined the effects of 24 wk of daily static stretching of the plantarflexors (unilateral 4 × 60-s stretching, whereas the contralateral leg served as a control; n = 26) on joint range of motion (ROM), muscle-tendon unit morphological and mechanical properties, neural activation, and contractile function. METHODS Torque-angle/velocity was obtained in passive and active conditions using isokinetic dynamometry, whereas muscle-tendon morphology and mechanical properties were examined using ultrasonography. RESULTS After the intervention, ROM increased (stretching, +11° ± 7°; control, 4° ± 8°), and passive torque (stretching, -10 ± 11 N·m; control, -7 ± 10 N·m) and normalized EMG amplitude (stretching, -3% ± 6%; control, -3% ± 4%) at a standardized dorsiflexion angle decreased. Increases were seen in passive tendon elongation at a standardized force (stretching, +1.3 ± 1.6 mm; control, +1.4 ± 2.1 mm) and in maximal passive muscle and tendon elongation. Angle of peak torque shifted toward dorsiflexion. No changes were seen in tendon stiffness, resting tendon length, or gastrocnemius medialis fascicle length. Conformable changes in ROM, passive dorsiflexion variables, tendon elongation, and angle of peak torque were observed in the nonstretched leg. CONCLUSIONS The present findings indicate that habitual stretching increases ROM and decreases passive torque, altering muscle-tendon behavior with the potential to modify contractile function.
Collapse
Affiliation(s)
- Marie M Moltubakk
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, NORWAY
| | | | - Melina M Magulas
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, NORWAY
| | | | - Olivier R Seynnes
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, NORWAY
| | | |
Collapse
|
22
|
Monti E, Waldvogel J, Ritzmann R, Freyler K, Albracht K, Helm M, De Cesare N, Pavan P, Reggiani C, Gollhofer A, Narici MV. Muscle in Variable Gravity: "I Do Not Know Where I Am, But I Know What to Do". Front Physiol 2021; 12:714655. [PMID: 34421657 PMCID: PMC8371909 DOI: 10.3389/fphys.2021.714655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/13/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose: Fascicle and sarcomere lengths are important predictors of muscle mechanical performance. However, their regulation during stretch-shortening cycle (SSC) activities in usual and challenging conditions is poorly understood. In this study, we aimed to investigate muscle fascicle and sarcomere behavior during drop jumps (a common SSC activity) in conditions of variable gravity. Methods: Fifteen volunteers performed repeated drop jumps in 1 g, hypo-gravity (0 to 1 g), and hyper-gravity (1 to 2 g) during a parabolic flight. Gastrocnemius medialis (GM) electromyographic activity and fascicle length (Lf) were measured at drop-off, ground contact (GC), minimum ankle joint angle (MAJ), and push-off. GM sarcomere number was estimated by dividing Lf, measured by ultrasound at rest, by published data on GM sarcomere length, and measured in vivo at the same joint angle. Changes in sarcomere length were estimated by dividing GM Lf in each jump phase by sarcomere number calculated individually. The sarcomere force-generating capacity in each jump phase was estimated from the sarcomere length-tension relationship previously reported in the literature. Results: The results showed that, regardless of the gravity level, GM sarcomeres operated in the ascending portion of their length-tension relationship in all the jump phases. Interestingly, although in hypo-gravity and hyper-gravity during the braking phase (GC-MAJ) GM fascicles and sarcomeres experienced a stretch (as opposed to the quasi-isometric behavior in 1 g), at MAJ they reached similar lengths as in 1 g, allowing sarcomeres to develop about the 70% of their maximum force. Conclusion: The observed fascicle behavior during drop jumping seems useful for anchoring the tendon, enabling storage of elastic energy and its release in the subsequent push-off phase for effectively re-bouncing in all gravity levels, suggesting that an innate neuromuscular wisdom enables to perform SSC movements also in challenging conditions.
Collapse
Affiliation(s)
- Elena Monti
- Department of Biomedical Science, University of Padova, Padova, Italy
| | - Janice Waldvogel
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Ramona Ritzmann
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany.,Department of Biomechanics, Rennbahnklinik, Muttenz, Switzerland
| | - Kathrin Freyler
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Kirsten Albracht
- Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany.,Department of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany
| | - Michael Helm
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Niccolò De Cesare
- Department of Industrial Engineering, University of Padova, Padova, Italy
| | - Piero Pavan
- Department of Industrial Engineering, University of Padova, Padova, Italy
| | - Carlo Reggiani
- Department of Biomedical Science, University of Padova, Padova, Italy
| | - Albert Gollhofer
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | | |
Collapse
|
23
|
Serial sarcomere number is substantially decreased within the paretic biceps brachii in individuals with chronic hemiparetic stroke. Proc Natl Acad Sci U S A 2021; 118:2008597118. [PMID: 34172565 DOI: 10.1073/pnas.2008597118] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A muscle's structure, or architecture, is indicative of its function and is plastic; changes in input to or use of the muscle alter its architecture. Stroke-induced neural deficits substantially alter both input to and usage of individual muscles. We combined in vivo imaging methods (second-harmonic generation microendoscopy, extended field-of-view ultrasound, and fat-suppression MRI) to quantify functionally meaningful architecture parameters in the biceps brachii of both limbs of individuals with chronic hemiparetic stroke and in age-matched, unimpaired controls. Specifically, serial sarcomere number (SSN) and physiological cross-sectional area (PCSA) were calculated from data collected at three anatomical scales: sarcomere length, fascicle length, and muscle volume. The interlimb differences in SSN and PCSA were significantly larger for stroke participants than for participants without stroke (P = 0.0126 and P = 0.0042, respectively), suggesting we observed muscle adaptations associated with stroke rather than natural interlimb variability. The paretic biceps brachii had ∼8,200 fewer serial sarcomeres and ∼2 cm2 smaller PCSA on average than the contralateral limb (both P < 0.0001). This was manifested by substantially smaller muscle volumes (112 versus 163 cm3), significantly shorter fascicles (11.0 versus 14.0 cm; P < 0.0001), and comparable sarcomere lengths (3.55 versus 3.59 μm; P = 0.6151) between limbs. Most notably, this study provides direct evidence of the loss of serial sarcomeres in human muscle observed in a population with neural impairments that lead to disuse and chronically place the affected muscle at a shortened position. This adaptation is consistent with functional consequences (increased passive resistance to elbow extension) that would amplify already problematic, neurally driven motor impairments.
Collapse
|
24
|
Sonay AY, Kalyviotis K, Yaganoglu S, Unsal A, Konantz M, Teulon C, Lieberwirth I, Sieber S, Jiang S, Behzadi S, Crespy D, Landfester K, Roke S, Lengerke C, Pantazis P. Biodegradable Harmonophores for Targeted High-Resolution In Vivo Tumor Imaging. ACS NANO 2021; 15:4144-4154. [PMID: 33630589 PMCID: PMC8023799 DOI: 10.1021/acsnano.0c10634] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 02/05/2021] [Indexed: 05/31/2023]
Abstract
Optical imaging probes have played a major role in detecting and monitoring a variety of diseases. In particular, nonlinear optical imaging probes, such as second harmonic generating (SHG) nanoprobes, hold great promise as clinical contrast agents, as they can be imaged with little background signal and unmatched long-term photostability. As their chemical composition often includes transition metals, the use of inorganic SHG nanoprobes can raise long-term health concerns. Ideally, contrast agents for biomedical applications should be degraded in vivo without any long-term toxicological consequences to the organism. Here, we developed biodegradable harmonophores (bioharmonophores) that consist of polymer-encapsulated, self-assembling peptides that generate a strong SHG signal. When functionalized with tumor cell surface markers, these reporters can target single cancer cells with high detection sensitivity in zebrafish embryos in vivo. Thus, bioharmonophores will enable an innovative approach to cancer treatment using targeted high-resolution optical imaging for diagnostics and therapy.
Collapse
Affiliation(s)
- Ali Yasin Sonay
- Department
of Biosystems Science and Engineering (D-BSSE), Eidgenössische Technische Hochschule (ETH) Zurich, 4058 Basel, Switzerland
| | - Konstantinos Kalyviotis
- Department
of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Sine Yaganoglu
- Department
of Biosystems Science and Engineering (D-BSSE), Eidgenössische Technische Hochschule (ETH) Zurich, 4058 Basel, Switzerland
| | - Aysen Unsal
- Department
of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Martina Konantz
- Department
of Biomedicine, University Hospital Basel
and University of Basel, 4031 Basel, Switzerland
| | - Claire Teulon
- Laboratory
for Fundamental BioPhotonics, Institute of Bioengineering, School
of Engineering, École Polytechnique
Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | | | - Sandro Sieber
- Division
of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel, 4031 Basel, Switzerland
| | - Shuai Jiang
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Shahed Behzadi
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Daniel Crespy
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
- Department
of Materials Science and Engineering, School of Molecular Science
and Engineering, Vidyasirimedhi Institute
of Science and Technology (VISTEC), Rayong 21210, Thailand
| | | | - Sylvie Roke
- Laboratory
for Fundamental BioPhotonics, Institute of Bioengineering, School
of Engineering, École Polytechnique
Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, School of Engineering, École Polytechnique Fédérale
de Lausanne, 1015 Lausanne, Switzerland
- Lausanne
Centre for Ultrafast Science, École
Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Claudia Lengerke
- Department
of Biomedicine, University Hospital Basel
and University of Basel, 4031 Basel, Switzerland
- Division
of Hematology, University Hospital Basel, 4031 Basel, Switzerland
| | - Periklis Pantazis
- Department
of Biosystems Science and Engineering (D-BSSE), Eidgenössische Technische Hochschule (ETH) Zurich, 4058 Basel, Switzerland
- Department
of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
| |
Collapse
|
25
|
Carraro U, Yablonka-Reuveni Z. Translational research on Myology and Mobility Medicine: 2021 semi-virtual PDM3 from Thermae of Euganean Hills, May 26 - 29, 2021. Eur J Transl Myol 2021; 31:9743. [PMID: 33733717 PMCID: PMC8056169 DOI: 10.4081/ejtm.2021.9743] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/17/2021] [Indexed: 02/08/2023] Open
Abstract
On 19-21 November 2020, the meeting of the 30 years of the Padova Muscle Days was virtually held while the SARS-CoV-2 epidemic was hitting the world after a seemingly quiet summer. During the 2020-2021 winter, the epidemic is still active, despite the start of vaccinations. The organizers hope to hold the 2021 Padua Days on Myology and Mobility Medicine in a semi-virtual form (2021 S-V PDM3) from May 26 to May 29 at the Thermae of Euganean Hills, Padova, Italy. Here the program and the Collection of Abstracts are presented. Despite numerous world problems, the number of submitted/selected presentations (lectures and oral presentations) has increased, prompting the organizers to extend the program to four dense days.
Collapse
Affiliation(s)
- Ugo Carraro
- Department of Biomedical Sciences of the University of Padova, Italy; CIR-Myo - Myology Centre, University of Padova, Italy; A-C Mioni-Carraro Foundation for Translational Myology, Padova.
| | - Zipora Yablonka-Reuveni
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA.
| |
Collapse
|
26
|
Heskamp L, Birkbeck MG, Whittaker RG, Schofield IS, Blamire AM. The muscle twitch profile assessed with motor unit magnetic resonance imaging. NMR IN BIOMEDICINE 2021; 34:e4466. [PMID: 33410277 PMCID: PMC7900994 DOI: 10.1002/nbm.4466] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 11/29/2020] [Accepted: 12/09/2020] [Indexed: 05/03/2023]
Abstract
Localised signal voids in diffusion-weighted (DW) images of skeletal muscle have been postulated to occur as a result of muscle fibre contraction and relaxation. We investigated the contrast mechanism of these signal voids using a combination of modelling and experimental measurements by employing DW and phase contrast (PC) imaging sequences. The DW signal and PC signal were simulated for each time point of a theoretical muscle twitch. The model incorporated compaction (simulating actively contracting muscle fibres) and translation (simulating passively moving surrounding fibres). The model suggested that the DW signal depended on contraction time and compaction whereas the PC signal depended on contraction time, compaction and translation. In a retrospective study, we tested this model with subgroup analyses on 10 healthy participants. Electrical nerve stimulation was used to generate muscle twitches in lower leg muscles; the resulting force was measured using an MR-compatible force transducer. At current levels causing a visible muscle twitch (~13 mA), the width of the first signal drop in the DW signal (mean ± SD: 103 ± 20 ms) was comparable with the force contraction time (93 ± 34 ms; intraclass correlation coefficient [ICC] = 0.717, P = .010). At current levels activating single motor units (~9 mA), the contraction time determined from the DW signal was 75 ± 13 ms and comparable with the PC contraction time (81 ± 15 ms; ICC = 0.925, P = .001). The maximum positive velocity was 0.55 ± 0.26 cm/s and the displacement was 0.20 ± 0.10 mm. Voxel-wise analysis revealed localised DW changes occurring together with more widespread phase changes. In conclusion, local signal attenuations in DW images following muscle fibre activation are primarily caused by compaction. The PC sequence also detects translating muscle tissue being passively pulled. The magnitude of the changes in DW and PC images depends on the twitch's contractile properties and percentage contraction. DW imaging and PC imaging can therefore measure twitch profiles of skeletal muscle fibres.
Collapse
Affiliation(s)
- Linda Heskamp
- Newcastle University Translational and Clinical Research Institute (NUTCRI)Newcastle UniversityNewcastle upon TyneUK
| | - Matthew G. Birkbeck
- Newcastle University Translational and Clinical Research Institute (NUTCRI)Newcastle UniversityNewcastle upon TyneUK
- Newcastle Biomedical Research CentreNewcastle UniversityNewcastle upon TyneUK
- Northern Medical Physics and Clinical EngineeringFreeman Hospital, Newcastle upon Tyne NHS Foundation TrustNewcastle upon TyneUK
| | - Roger G. Whittaker
- Newcastle University Translational and Clinical Research Institute (NUTCRI)Newcastle UniversityNewcastle upon TyneUK
| | - Ian S. Schofield
- Newcastle University Translational and Clinical Research Institute (NUTCRI)Newcastle UniversityNewcastle upon TyneUK
| | - Andrew M. Blamire
- Newcastle University Translational and Clinical Research Institute (NUTCRI)Newcastle UniversityNewcastle upon TyneUK
| |
Collapse
|
27
|
James DS, Campagnola PJ. Recent Advancements in Optical Harmonic Generation Microscopy: Applications and Perspectives. BME FRONTIERS 2021; 2021:3973857. [PMID: 37849910 PMCID: PMC10521653 DOI: 10.34133/2021/3973857] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 12/14/2020] [Indexed: 10/19/2023] Open
Abstract
Second harmonic generation (SHG) and third harmonic generation (THG) microscopies have emerged as powerful imaging modalities to examine structural properties of a wide range of biological tissues. Although SHG and THG arise from very different contrast mechanisms, the two are complimentary and can often be collected simultaneously using a modified multiphoton microscope. In this review, we discuss the needed instrumentation for these modalities as well as the underlying theoretical principles of SHG and THG in tissue and describe how these can be leveraged to extract unique structural information. We provide an overview of recent advances showing how SHG microscopy has been used to evaluate collagen alterations in the extracellular matrix and how this has been used to advance our knowledge of cancers, fibroses, and the cornea, as well as in tissue engineering applications. Specific examples using polarization-resolved approaches and machine learning algorithms are highlighted. Similarly, we review how THG has enabled developmental biology and skin cancer studies due to its sensitivity to changes in refractive index, which are ubiquitous in all cell and tissue assemblies. Lastly, we offer perspectives and outlooks on future directions of SHG and THG microscopies and present unresolved questions, especially in terms of overall miniaturization and the development of microendoscopy instrumentation.
Collapse
Affiliation(s)
- Darian S. James
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Dr, Madison, WI 53706, USA
| | - Paul J. Campagnola
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Dr, Madison, WI 53706, USA
| |
Collapse
|
28
|
Sahu SP, Liu Q, Prasad A, Hasan SMA, Liu Q, Rodriguez MXB, Mukhopadhyay O, Burk D, Francis J, Mukhopadhyay S, Fu X, Gartia MR. Characterization of fibrillar collagen isoforms in infarcted mouse hearts using second harmonic generation imaging. BIOMEDICAL OPTICS EXPRESS 2021; 12:604-618. [PMID: 33520391 PMCID: PMC7818962 DOI: 10.1364/boe.410347] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/14/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
We utilized collagen specific second harmonic generation (SHG) signatures coupled with correlative immunofluorescence imaging techniques to characterize collagen structural isoforms (type I and type III) in a murine model of myocardial infarction (MI). Tissue samples were imaged over a four week period using SHG, transmitted light microscopy and immunofluorescence imaging using fluorescently-labeled collagen antibodies. The post-mortem cardiac tissue imaging using SHG demonstrated a progressive increase in collagen deposition in the left ventricle (LV) post-MI. We were able to monitor structural morphology and LV remodeling parameters in terms of extent of LV dilation, stiffness and fiber dimensions in the infarcted myocardium.
Collapse
Affiliation(s)
- Sushant P Sahu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - Qianglin Liu
- LSU AgCenter, School of Animal Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Alisha Prasad
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Syed Mohammad Abid Hasan
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Qun Liu
- Department of Computer Science, Louisiana State University, Baton Rouge, LA 70803, USA
| | | | | | - David Burk
- Shared Instrumentation Facility and Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Joseph Francis
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Supratik Mukhopadhyay
- Department of Computer Science, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Xing Fu
- LSU AgCenter, School of Animal Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Manas Ranjan Gartia
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
| |
Collapse
|
29
|
Effectiveness of Intramuscular Electrical Stimulation on Postsurgical Nociceptive Pain for Patients Undergoing Open Pancreaticoduodenectomy: A Randomized Clinical Trial. J Am Coll Surg 2020; 231:339-350. [PMID: 32623088 DOI: 10.1016/j.jamcollsurg.2020.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 05/30/2020] [Accepted: 06/02/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND After pylorus-preserving pancreaticoduodenectomy (PPPD), incision and suture of the abdominal muscles cause inflammatory changes and elicit somatic pain that deteriorates the quality of life. There have been no previous reports on needle electrical twitch obtaining intramuscular stimulation (NETOIMS) in abdominal open operation; this study aimed to apply NETOIMS for postoperative somatic pain in patients undergoing PPPD as a new treatment modality for pain control. METHODS Between June 2018 and January 2019, 44 patients who underwent PPPD were randomly assigned to a control group and the NETOIMS group. The NETOIMS group received NETOIMS in the transverse abdominis muscle under ultrasound guidance right after operation under general anesthesia. The pain score (visual analog scale), peak cough flow (PCF), and gait speed were repetitively measured from 1 day before operation to 2 weeks after discharge as scheduled. Data were analyzed by the linear mixed model and repeated-measures analysis of variance. RESULTS Of the 44 patients recruited, data from 38 patients were finally analyzed. The pain scores were significantly lower in the NETOIMS group after PPPD (p = 0.01). Although the PCF at each measuring time point did not show inter-group difference (p = 0.20), improvement of PCF from the second day after operation to discharge was greater (p = 0.02) and gait speed improved significantly faster (p < 0.01) in the NETOIMS group than in the control group. CONCLUSIONS NETOIMS helps in rapid reduction of postoperative somatic pain developed after PPPD and in improvement of PCF and gait speed.
Collapse
|
30
|
The Mechanical Power of Titin Folding. Cell Rep 2020; 27:1836-1847.e4. [PMID: 31067467 PMCID: PMC6937205 DOI: 10.1016/j.celrep.2019.04.046] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/09/2019] [Accepted: 04/09/2019] [Indexed: 11/21/2022] Open
Abstract
The delivery of mechanical power, a crucial component of animal motion, is constrained by the universal compromise between the force and the velocity of its constituent molecular systems. While the mechanisms of force generation have been studied at the single molecular motor level, there is little understanding of the magnitude of power that can be generated by folding proteins. Here, we use single-molecule force spectroscopy techniques to measure the force-velocity relation of folding titin domains that contain single internal disulfide bonds, a common feature throughout the titin I-band. We find that formation of the disulfide regulates the peak power output of protein folding in an all-or-none manner, providing at 6.0 pN, for example, a boost from 0 to 6,000 zW upon oxidation. This mechanism of power generation from protein folding is of great importance for muscle, where titin domains may unfold and refold with each extension and contraction of the sarcomere. Eckels et al. use single-molecule magnetic tweezers to simultaneously probe the folding dynamics of titin Ig domains and monitor the redox status of single disulfides within the Ig fold. Oxidation of the disulfide bond greatly increases both the folding force and the magnitude of power delivered by protein folding.
Collapse
|
31
|
Moo EK, Herzog W. Sarcomere Lengths Become More Uniform Over Time in Intact Muscle-Tendon Unit During Isometric Contractions. Front Physiol 2020; 11:448. [PMID: 32477162 PMCID: PMC7235410 DOI: 10.3389/fphys.2020.00448] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/09/2020] [Indexed: 12/12/2022] Open
Abstract
The seemingly uniform striation pattern of skeletal muscles, quantified in terms of sarcomere lengths (SLs), is inherently non-uniform across all hierarchical levels. The SL non-uniformity theory has been used to explain the force creep in isometric contractions, force depression following shortening of activated muscle, and residual force enhancement following lengthening of activated muscle. Our understanding of sarcomere contraction dynamics has been derived primarily from in vitro experiments using regular bright-field light microscopy or laser diffraction techniques to measure striation/diffraction patterns in isolated muscle fibers or myofibrils. However, the collagenous extracellular matrices present around the muscle fibers, as well as the complex architecture in the whole muscles may lead to different contraction dynamics of sarcomeres than seen in the in vitro studies. Here, we used multi-photon excitation microscopy to visualize in situ individual sarcomeres in intact muscle tendon units (MTUs) of mouse tibialis anterior (TA), and quantified the temporal changes of SL distribution as a function of SLs in relaxed and maximally activated muscles for quasi-steady state, fixed-end isometric conditions. The corresponding muscle forces were simultaneously measured using a force transducer. We found that SL non-uniformity, quantified by the coefficient of variation (CV) of SLs, decreased at a rate of 1.9–3.1%/s in the activated muscles, but remained constant in the relaxed muscles. The force loss during the quasi-steady state likely did not play a role in the decrease of SL non-uniformity, as similar force losses were found in the activated and relaxed muscles, but the CV of SLs in the relaxed muscles underwent negligible change over time. We conclude that sarcomeres in the mid-belly of maximally contracting whole muscles constantly re-organize their lengths into a more uniform pattern over time. The molecular mechanisms accounting for SL non-uniformity appear to differ in active and passive muscles, and need further elucidation, as do the functional implications of the SL non-uniformity.
Collapse
Affiliation(s)
- Eng Kuan Moo
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Walter Herzog
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| |
Collapse
|
32
|
Moo EK, Leonard TR, Herzog W. The sarcomere force-length relationship in an intact muscle-tendon unit. J Exp Biol 2020; 223:jeb215020. [PMID: 32098882 DOI: 10.1242/jeb.215020] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 02/18/2020] [Indexed: 08/26/2023]
Abstract
The periodic striation pattern in skeletal muscle reflects the length of the basic contractile unit: the sarcomere. More than half a century ago, Gordon, Huxley and Julian provided strong support for the 'sliding filament' theory through experiments with single muscle fibres. The sarcomere force-length (FL) relationship has since been extrapolated to whole muscles in an attempt to unravel in vivo muscle function. However, these extrapolations were frequently associated with non-trivial assumptions, such as muscle length changes corresponding linearly to SL changes. Here, we determined the in situ sarcomere FL relationship in a whole muscle preparation by simultaneously measuring muscle force and individual SLs in an intact muscle-tendon unit (MTU) using state-of-the-art multi-photon excitation microscopy. We found that despite great SL non-uniformity, the mean value of SLs measured from a minute volume of the mid-belly, equivalent to about 5×10-6% of the total muscle volume, agrees well with the theoretically predicted FL relationship, but only if the precise contractile filament lengths are known, and if passive forces from parallel elastic components and activation-associated sarcomere shortening are considered properly. As SLs are not uniformly distributed across the whole muscle and changes in SL with muscle length are location dependent, our results may not be valid for the proximal or distal parts of the muscle. The approach described here, and our findings, may encourage future studies to determine the role of SL non-uniformity in influencing sarcomere FL properties in different muscles and for different locations within single muscles.
Collapse
Affiliation(s)
- Eng Kuan Moo
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Timothy R Leonard
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Walter Herzog
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada T2N 1N4
| |
Collapse
|
33
|
Chen X, Sanchez GN, Schnitzer MJ, Delp SL. Microendoscopy detects altered muscular contractile dynamics in a mouse model of amyotrophic lateral sclerosis. Sci Rep 2020; 10:457. [PMID: 31949214 PMCID: PMC6965652 DOI: 10.1038/s41598-019-56555-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/07/2019] [Indexed: 02/06/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease involving motor neuron degeneration. Effective diagnosis of ALS and quantitative monitoring of its progression are crucial to the success of clinical trials. Second harmonic generation (SHG) microendoscopy is an emerging technology for imaging single motor unit contractions. To assess the potential value of microendoscopy for diagnosing and tracking ALS, we monitored motor unit dynamics in a B6.SOD1G93A mouse model of ALS for several weeks. Prior to overt symptoms, muscle twitch rise and relaxation time constants both increased, consistent with a loss of fast-fatigable motor units. These effects became more pronounced with disease progression, consistent with the death of fast fatigue-resistant motor units and superior survival of slow motor units. From these measurements we constructed a physiological metric that reflects the changing distributions of measured motor unit time constants and effectively diagnoses mice before symptomatic onset and tracks disease state. These results indicate that SHG microendoscopy provides a means for developing a quantitative, physiologic characterization of ALS progression.
Collapse
Affiliation(s)
- Xuefeng Chen
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Gabriel N Sanchez
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Enspectra Health, Mountain View, CA, 94040, USA
| | - Mark J Schnitzer
- Department of Biology, Stanford University, Stanford, CA, 94305, USA.
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305, USA.
| | - Scott L Delp
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA.
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
| |
Collapse
|
34
|
Nelson CM, Marchese V, Rock K, Henshaw RM, Addison O. Alterations in Muscle Architecture: A Review of the Relevance to Individuals After Limb Salvage Surgery for Bone Sarcoma. Front Pediatr 2020; 8:292. [PMID: 32612962 PMCID: PMC7308581 DOI: 10.3389/fped.2020.00292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 05/07/2020] [Indexed: 11/13/2022] Open
Abstract
Osteosarcoma and Ewing's sarcoma are the most common primary bone malignancies affecting children and adolescents. Optimal treatment requires a combination of chemotherapy and/or radiation along with surgical removal when feasible. Advances in multiple aspects of surgical management have allowed limb salvage surgery (LSS) to supplant amputation as the most common procedure for these tumors. However, individuals may experience significant impairment after LSS, including deficits in range of motion and strength that limit function and impact participation in work, school, and the community, ultimately affecting quality of life. Muscle force and speed of contraction are important contributors to normal function during activities such as gait, stairs, and other functional tasks. Muscle architecture is the primary contributor to muscle function and adapts to various stimuli, including periods of immobilization-protected weightbearing after surgery. The impacts of LSS on muscle architecture and how adaptations may impact deficits within the rehabilitation period and into long-term survivorship is not well-studied. The purpose of this paper is to [1] provide relevant background on bone sarcomas and LSS, [2] highlight the importance of muscle architecture, its measurement, and alterations as seen in other relevant populations and [3] discuss the clinical relevance of muscle architectural changes and the impact on muscle dysfunction in this population. Understanding the changes that occur in muscle architecture and its impact on long-term impairments in bone sarcoma survivors is important in developing new rehabilitation treatments that optimize functional outcomes.
Collapse
Affiliation(s)
- Christa M Nelson
- Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Victoria Marchese
- Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Kelly Rock
- Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Robert M Henshaw
- Department of Orthopedic Oncology, MedStar Georgetown Orthopedic Institute, Washington, DC, United States.,Department of Orthopedic Oncology, Children's National Medical Center, Washington, DC, United States
| | - Odessa Addison
- Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD, United States.,Baltimore VA GRECC, Baltimore, MD, United States
| |
Collapse
|
35
|
Rentchler EC, Gant KL, Drapkin R, Patankar M, J. Campagnola P. Imaging Collagen Alterations in STICs and High Grade Ovarian Cancers in the Fallopian Tubes by Second Harmonic Generation Microscopy. Cancers (Basel) 2019; 11:cancers11111805. [PMID: 31744173 PMCID: PMC6896112 DOI: 10.3390/cancers11111805] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 11/14/2019] [Indexed: 11/17/2022] Open
Abstract
The majority of high-grade serous ovarian cancers originate in the fallopian tubes, however, the corresponding structural changes in the extracellular matrix (ECM) have not been well-characterized. This information could provide new insight into the carcinogenesis and provide the basis for new diagnostic tools. We have previously used the collagen-specific Second Harmonic Generation (SHG) microscopy to probe collagen fiber alterations in high-grade serous ovarian cancer and in other ovarian tumors, and showed they could be uniquely identified by machine learning approaches. Here we couple SHG imaging of serous tubal intra-epithelial carcinomas (STICs), high-grade cancers, and normal regions of the fallopian tubes, using three distinct image analysis approaches to form a classification scheme based on the respective collagen fiber morphology. Using a linear discriminant analysis, we achieved near 100% classification accuracy between high-grade disease and the other tissues, where the STICs and normal regions were differentiated with ~75% accuracy. Importantly, the collagen in high-grade disease in both the fallopian tube and the ovary itself have a similar collagen morphology, further substantiating the metastasis between these sites. This analysis provides a new method of classification, but also quantifies the structural changes in the disease, which may provide new insight into metastasis.
Collapse
Affiliation(s)
- Eric C. Rentchler
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, USA;
| | - Kristal L. Gant
- Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53706, USA; (K.L.G.); (M.P.)
| | - Ronny Drapkin
- Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Manish Patankar
- Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53706, USA; (K.L.G.); (M.P.)
| | - Paul J. Campagnola
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, USA;
- Correspondence:
| |
Collapse
|
36
|
Eckels EC, Tapia-Rojo R, Rivas-Pardo JA, Fernández JM. The Work of Titin Protein Folding as a Major Driver in Muscle Contraction. Annu Rev Physiol 2019; 80:327-351. [PMID: 29433413 DOI: 10.1146/annurev-physiol-021317-121254] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Single-molecule atomic force microscopy and magnetic tweezers experiments have demonstrated that titin immunoglobulin (Ig) domains are capable of folding against a pulling force, generating mechanical work that exceeds that produced by a myosin motor. We hypothesize that upon muscle activation, formation of actomyosin cross bridges reduces the force on titin, causing entropic recoil of the titin polymer and triggering the folding of the titin Ig domains. In the physiological force range of 4-15 pN under which titin operates in muscle, the folding contraction of a single Ig domain can generate 200% of the work of entropic recoil and occurs at forces that exceed the maximum stalling force of single myosin motors. Thus, titin operates like a mechanical battery, storing elastic energy efficiently by unfolding Ig domains and delivering the charge back by folding when the motors are activated during a contraction. We advance the hypothesis that titin folding and myosin activation act as inextricable partners during muscle contraction.
Collapse
Affiliation(s)
- Edward C Eckels
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; , .,Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Medical Center, New York, NY 10032, USA
| | - Rafael Tapia-Rojo
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; ,
| | | | - Julio M Fernández
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; ,
| |
Collapse
|
37
|
Hullfish TJ, O’Connor KM, Baxter JR. Gastrocnemius fascicles are shorter and more pennate throughout the first month following acute Achilles tendon rupture. PeerJ 2019; 7:e6788. [PMID: 31065459 PMCID: PMC6485203 DOI: 10.7717/peerj.6788] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/14/2019] [Indexed: 12/28/2022] Open
Abstract
The purpose of this study was to characterize the short-term effects of Achilles tendon ruptures on medial gastrocnemius. We hypothesized that the fascicles of the medial gastrocnemius muscle of the injured Achilles tendon would be shorter and more pennate immediately following the injury and would persist throughout 4 weeks post-injury. B-mode longitudinal ultrasound images of the medial gastrocnemius were acquired in 10 adults who suffered acute Achilles tendon ruptures and were treated non-operatively. Ultrasound images were acquired during the initial clinical visit following injury as well as 2 and 4 weeks following this initial clinical visit. Resting muscle structure was characterized by measuring fascicle length, pennation angle, muscle thickness, and muscle echo intensity in both the injured and contralateral (control) limbs. Fascicle length was 15% shorter (P < 0.001) and pennation angle was 21% greater (P < 0.001) in the injured muscle compared to the uninjured (control) muscle at the presentation of injury (week 0). These differences in fascicle length persisted through 4 weeks after injury (P < 0.002) and pennation angle returned to pre-injury levels. Muscle thickness changes were not detected at any of the post-injury visits (difference < 4%, P > 0.026). Echo intensity of the injured limb was 8% lower at the presentation of the injury but was not different compared to the contralateral muscle at 2 and 4 weeks post-injury. Our results suggest that Achilles tendon ruptures elicit rapid changes in the configuration of the medial gastrocnemius, which may explain long-term functional deficits.
Collapse
Affiliation(s)
- Todd J. Hullfish
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn M. O’Connor
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Josh R. Baxter
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
38
|
Lichtwark GA, Farris DJ, Chen X, Hodges PW, Delp SL. Microendoscopy reveals positive correlation in multiscale length changes and variable sarcomere lengths across different regions of human muscle. J Appl Physiol (1985) 2018; 125:1812-1820. [DOI: 10.1152/japplphysiol.00480.2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sarcomere length is a key physiological parameter that affects muscle force output; however, our understanding of the scaling of human muscle from sarcomere to whole muscle is based primarily on cadaveric data. The aims of this study were to explore the in vivo relationship between passive fascicle length and passive sarcomere length at different muscle-tendon unit lengths and determine whether sarcomere and fascicle length relationships are the same in different regions of muscle. A microendoscopy needle probe capable of in vivo sarcomere imaging was inserted into a proximal location of the human tibialis anterior muscle at three different ankle positions [5° dorsiflexion, 5° plantar flexion (PF), and 15° PF] and one distal location at a constant ankle position (5° PF distal). Ultrasound imaging of tibialis anterior fascicles, centered on the location of the needle probe, was performed for each condition to estimate fascicle length. Sarcomere length and fascicle length increased with increasing muscle-tendon unit length, although the correlation between sarcomere length change and muscle fascicle length change was only moderate ( r2 = 0.45). Passive sarcomere length was longer at the distal imaging site than the proximal site ( P = 0.01). When sarcomere number was estimated from sarcomere length and fascicle length, there were fewer sarcomeres in the fibers of distal location than the proximal location ( P = 0.01). These data demonstrate that fascicle length changes are representative of sarcomere length changes, although significant variability in sarcomere length exists within a muscle and sarcomere number per fiber is region-dependent. NEW & NOTEWORTHY Sarcomere and fascicle lengths were measured in vivo from human muscle to examine the relationship between the different scales of organization. Changes in fascicle length were moderately related to sarcomere length changes; however, sarcomere length and number per fiber varied from proximal to distal regions of the muscle. Differences in average sarcomere operating lengths across the muscle suggest potentially different stresses or strains experienced within different regions of muscle.
Collapse
Affiliation(s)
- Glen A. Lichtwark
- School of Human Movement and Nutrition Sciences, Centre for Sensorimotor Performance, The University of Queensland, Brisbane, Queensland, Australia
| | - Dominic J. Farris
- School of Human Movement and Nutrition Sciences, Centre for Sensorimotor Performance, The University of Queensland, Brisbane, Queensland, Australia
- Sport and Health Sciences, College of Life and Environmental Sciences, The University of Exeter, Exeter, United Kingdom
| | - Xuefeng Chen
- Department of Bioengineering, Stanford University, Stanford, California
| | - Paul W. Hodges
- School of Health and Rehabilitation Sciences, Centre for Clinical Research Excellence in Spinal Pain, Injury, and Health, The University of Queensland, Brisbane, Queensland, Australia
| | - Scott L. Delp
- Department of Bioengineering, Stanford University, Stanford, California
| |
Collapse
|
39
|
Nelson CM, Murray WM, Dewald JPA. Motor Impairment-Related Alterations in Biceps and Triceps Brachii Fascicle Lengths in Chronic Hemiparetic Stroke. Neurorehabil Neural Repair 2018; 32:799-809. [PMID: 30136897 DOI: 10.1177/1545968318792618] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Poststroke deficits in upper extremity function occur during activities of daily living due to motor impairments of the paretic arm, including weakness and abnormal synergies, both of which result in altered use of the paretic arm. Over time, chronic disuse and a resultant flexed elbow posture may result in secondary changes in the musculoskeletal system that may limit use of the arm and impact functional mobility. This study utilized extended field-of-view ultrasound to measure fascicle lengths of the biceps (long head) and triceps (distal portion of the lateral head) brachii in order to investigate secondary alterations in muscles of the paretic elbow. Data were collected from both arms in 11 individuals with chronic hemiparetic stroke, with moderate to severe impairment as classified by the Fugl-Meyer assessment score. Across all participants, significantly shorter fascicles were observed in both biceps and triceps brachii ( P < .0005) in the paretic limb under passive conditions. The shortening in paretic fascicle length relative to the nonparetic arm measured under passive conditions remained observable during active muscle contraction for the biceps but not for the triceps brachii. Finally, average fascicle length differences between arms were significantly correlated to impairment level, with more severely impaired participants showing greater shortening of paretic biceps fascicle length relative to changes seen in the triceps across all elbow positions ( r = -0.82, P = .002). Characterization of this secondary adaptation is necessary to facilitate development of interventions designed to reduce or prevent the shortening from occurring in the acute stages of recovery poststroke.
Collapse
Affiliation(s)
| | - Wendy M Murray
- 2 Northwestern University, Evanston, IL, USA.,3 Shirley Ryan AbilityLab (formerly Rehabilitation Institute of Chicago), Chicago, IL, USA.,4 Edward Hines, Jr. VA Hospital, Hines, IL, USA
| | | |
Collapse
|
40
|
de Brito Fontana H, de Campos D, Sakugawa RL. Predictors of residual force enhancement in voluntary contractions of elbow flexors. JOURNAL OF SPORT AND HEALTH SCIENCE 2018; 7:318-325. [PMID: 30356605 PMCID: PMC6189239 DOI: 10.1016/j.jshs.2018.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 01/24/2018] [Accepted: 02/20/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND The steady-state increase in muscle force generating potential following a lengthening contraction is called residual force enhancement (RFE). In this study, we aimed to test for differences in torque, electromyographic activity (EMG), and the associated neuromuscular efficiency (NME) between isometric voluntary contractions of elbow flexors preceded and not preceded by a lengthening contraction. The dependence of such differences on (i) stretch amplitude, (ii) the region of the force-length (FxL) relationship where contraction occurs, and (iii) the individual's ability to produce (negative) work during the stretch was investigated. METHODS Sixteen healthy adults participated in the study. Elbow flexor torque, angle, and biceps brachii EMG for purely isometric contractions (reference contractions) and for isometric contractions preceded by active stretches of 20° and 40° were measured at the ascending, plateau, and descending regions of subject-specific FxL curves. All contractions were performed in an isokinetic dynamometer. Two-factor (stretch × FxL region) repeated measures analysis of variance ANOVAs was used to analyze the effect of active stretch on EMG, torque, and NME across conditions. The relationships between mechanical work during stretch-calculated as the torque-angular displacement integral-and the changes in EMG, torque, and NME were analyzed using Pearson correlation. RESULTS In general, torque, EMG, and NME following active stretches differed from the values observed for the purely isometric reference contractions. While although the detailed effects of active stretch on torque and EMG differed between regions of the FxL relationship, NME increased by about 19% for all muscle lengths. Up to 30% of the interindividual variability in torque generating potential change in response to active stretching was accounted for by differences in (negative) work capacity between subjects. CONCLUSION Our results suggest that (i) RFE contributes to "flatten" the elbow flexor torque-angle relationship, favoring torque production at lengths where the purely isometric torques are reduced substantially, and (ii) RFE contributes to a reduction in energy cost of torque production during isometric contractions for the entire operating range.
Collapse
Affiliation(s)
- Heiliane de Brito Fontana
- Biological Sciences Center, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima, Florianópolis, SC 88040-900, Brazil
- Biomechanics Laboratory, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima, Florianópolis, SC 88040-900, Brazil
| | - Daiani de Campos
- Biomechanics Laboratory, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima, Florianópolis, SC 88040-900, Brazil
| | - Raphael Luiz Sakugawa
- Biomechanics Laboratory, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima, Florianópolis, SC 88040-900, Brazil
| |
Collapse
|
41
|
Mostaço-Guidolin L, Rosin NL, Hackett TL. Imaging Collagen in Scar Tissue: Developments in Second Harmonic Generation Microscopy for Biomedical Applications. Int J Mol Sci 2017; 18:E1772. [PMID: 28809791 PMCID: PMC5578161 DOI: 10.3390/ijms18081772] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 01/13/2023] Open
Abstract
The ability to respond to injury with tissue repair is a fundamental property of all multicellular organisms. The extracellular matrix (ECM), composed of fibrillar collagens as well as a number of other components is dis-regulated during repair in many organs. In many tissues, scaring results when the balance is lost between ECM synthesis and degradation. Investigating what disrupts this balance and what effect this can have on tissue function remains an active area of research. Recent advances in the imaging of fibrillar collagen using second harmonic generation (SHG) imaging have proven useful in enhancing our understanding of the supramolecular changes that occur during scar formation and disease progression. Here, we review the physical properties of SHG, and the current nonlinear optical microscopy imaging (NLOM) systems that are used for SHG imaging. We provide an extensive review of studies that have used SHG in skin, lung, cardiovascular, tendon and ligaments, and eye tissue to understand alterations in fibrillar collagens in scar tissue. Lastly, we review the current methods of image analysis that are used to extract important information about the role of fibrillar collagens in scar formation.
Collapse
Affiliation(s)
- Leila Mostaço-Guidolin
- Centre for Heart Lung Innovation, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada.
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada.
| | - Nicole L Rosin
- Centre for Heart Lung Innovation, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada.
| | - Tillie-Louise Hackett
- Centre for Heart Lung Innovation, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada.
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada.
| |
Collapse
|
42
|
Young KW, Kuo BPP, O'Connor SM, Radic S, Lieber RL. In Vivo Sarcomere Length Measurement in Whole Muscles during Passive Stretch and Twitch Contractions. Biophys J 2017; 112:805-812. [PMID: 28256239 DOI: 10.1016/j.bpj.2016.12.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/05/2016] [Accepted: 12/27/2016] [Indexed: 11/29/2022] Open
Abstract
Muscle force is dictated by micrometer-scale contractile machines called sarcomeres. Whole-muscle force drops from peak force production to zero with just a few micrometers of sarcomere length change. No current technology is able to capture adequate dynamic sarcomere data in vivo, and thus we lack fundamental data needed to understand human movement and movement disorders. Methods such as diffraction, endoscopy, and optical coherence tomography have been applied to muscle but are prohibitively invasive, sensitive to motion artifact, and/or imprecise. Here, we report dynamic sarcomere length measurement in vivo using a combination of our recently validated resonant reflection spectroscopy method combined with optical frequency domain interferometry. Using a 250-μm-wide fiber optic probe, we captured nanometer sarcomere length changes from thousands of sarcomeres on the sub-millisecond timescale during whole-muscle stretch and twitch contraction. We believe that this demonstrates the first large-scale sensing of sarcomere dynamics in vivo, which is a necessary first step to understand movement disorders and to create patient-specific surgical interventions and rehabilitation.
Collapse
Affiliation(s)
- Kevin W Young
- Department of Bioengineering, University of California, San Diego, La Jolla, California; VA San Diego Healthcare System, San Diego, California
| | - Bill P-P Kuo
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California
| | - Shawn M O'Connor
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Stojan Radic
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California
| | - Richard L Lieber
- Department of Bioengineering, University of California, San Diego, La Jolla, California; VA San Diego Healthcare System, San Diego, California; Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California; Rehabilitation Institute of Chicago and Northwestern University, Chicago, Illinois.
| |
Collapse
|
43
|
Marcucci L, Reggiani C, Natali AN, Pavan PG. From single muscle fiber to whole muscle mechanics: a finite element model of a muscle bundle with fast and slow fibers. Biomech Model Mechanobiol 2017; 16:1833-1843. [DOI: 10.1007/s10237-017-0922-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 05/19/2017] [Indexed: 10/19/2022]
|
44
|
Mertz L. Brain over Brawn: Smart Imaging Innovations Open Windows on Muscle, Provide Hope for Treating Degenerating Diseases, and More. IEEE Pulse 2017; 8:33-37. [DOI: 10.1109/mpul.2016.2647019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
45
|
Chen X, Delp SL. Human soleus sarcomere lengths measured using in vivo microendoscopy at two ankle flexion angles. J Biomech 2016; 49:4164-4167. [PMID: 27866676 PMCID: PMC6050010 DOI: 10.1016/j.jbiomech.2016.11.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 11/08/2016] [Accepted: 11/08/2016] [Indexed: 11/19/2022]
Abstract
The forces generated by the soleus muscle play an important role in standing and locomotion. The lengths of the sarcomeres of the soleus affect its force-generating capacity, yet it is unknown how sarcomere lengths in the soleus change as a function of ankle flexion angle. In this study, we used microendoscopy to measure resting sarcomere lengths at 10° plantarflexion and 20° dorsiflexion in 7 healthy individuals. Mean sarcomere lengths at 10° plantarflexion were 2.84±0.09µm (mean±S.E.M.), near the optimal length for sarcomere force generation. Sarcomere lengths were 3.43±0.09µm at 20° dorsiflexion, indicating that they were longer than optimal length when the ankle was in dorsiflexion and the muscle was inactive. Our results indicate a smaller sarcomere length difference between two ankle flexion angles compared to estimates from musculoskeletal models and suggest why these models frequently underestimate the force-generating capacity of the soleus.
Collapse
Affiliation(s)
- Xuefeng Chen
- Department of Mechanical Engineering, Stanford University, United States
| | - Scott L Delp
- Department of Mechanical Engineering, Stanford University, United States; Department of Bioengineering, Stanford University, United States.
| |
Collapse
|
46
|
Chen X, Sanchez GN, Schnitzer MJ, Delp SL. Changes in sarcomere lengths of the human vastus lateralis muscle with knee flexion measured using in vivo microendoscopy. J Biomech 2016; 49:2989-2994. [PMID: 27481293 DOI: 10.1016/j.jbiomech.2016.07.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 06/05/2016] [Accepted: 07/16/2016] [Indexed: 11/30/2022]
Abstract
Sarcomeres are the basic contractile units of muscle, and their lengths influence muscle force-generating capacity. Despite their importance, in vivo sarcomere lengths remain unknown for many human muscles. Second harmonic generation (SHG) microendoscopy is a minimally invasive technique for imaging sarcomeres in vivo and measuring their lengths. In this study, we used SHG microendoscopy to visualize sarcomeres of the human vastus lateralis, a large knee extensor muscle important for mobility, to examine how sarcomere lengths change with knee flexion and thus affect the muscle׳s force-generating capacity. We acquired in vivo sarcomere images of several muscle fibers of the resting vastus lateralis in six healthy individuals. Mean sarcomere lengths increased (p=0.031) from 2.84±0.16μm at 50° of knee flexion to 3.17±0.13μm at 110° of knee flexion. The standard deviation of sarcomere lengths among different fibers within a muscle was 0.21±0.09μm. Our results suggest that the sarcomeres of the resting vastus lateralis at 50° of knee flexion are near optimal length. At a knee flexion angle of 110° the resting sarcomeres of vastus lateralis are longer than optimal length. These results show a smaller sarcomere length change and greater conservation of force-generating capacity with knee flexion than estimated in previous studies.
Collapse
Affiliation(s)
- Xuefeng Chen
- Department of Mechanical Engineering, Stanford University, United States
| | - Gabriel N Sanchez
- Department of Mechanical Engineering, Stanford University, United States; Department of Bioengineering, Stanford University, United States
| | - Mark J Schnitzer
- Department of Biology, Stanford University, United States; Department of Applied Physics, Stanford University, United States; Howard Hughes Medical Institute, United States
| | - Scott L Delp
- Department of Mechanical Engineering, Stanford University, United States; Department of Bioengineering, Stanford University, United States.
| |
Collapse
|
47
|
Williams JC, Campagnola PJ. Wearable Second Harmonic Generation Imaging: The Sarcomeric Bridge to the Clinic. Neuron 2016; 88:1067-1069. [PMID: 26687213 DOI: 10.1016/j.neuron.2015.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Imaging of sarcomere dynamics in vivo in patients has significant clinical importance, as the structure and function is altered in numerous pathologies. In this issue of Neuron, Schnitzer and coworkers (Sanchez et al., 2015) demonstrate this capability through a miniature, wearable Second Harmonic Generation microscope.
Collapse
Affiliation(s)
- Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Drive, Madison, WI 53706, USA
| | - Paul J Campagnola
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Drive, Madison, WI 53706, USA.
| |
Collapse
|
48
|
Mercier L, Böhm J, Fekonja N, Allio G, Lutz Y, Koch M, Goetz JG, Laporte J. In vivo imaging of skeletal muscle in mice highlights muscle defects in a model of myotubular myopathy. INTRAVITAL 2016; 5:e1168553. [PMID: 28243519 DOI: 10.1080/21659087.2016.1168553] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 12/11/2022]
Abstract
Skeletal muscle structure and function are altered in different myopathies. However, the understanding of the molecular and cellular mechanisms mainly rely on in vitro and ex vivo investigations in mammalian models. In order to monitor in vivo the intracellular structure of the neuromuscular system in its environment under normal and pathological conditions, we set-up and validated non-invasive imaging of ear and leg muscles in mice. This original approach allows simultaneous imaging of different cellular and intracellular structures such as neuromuscular junctions and sarcomeres, reconstruction of the 3D architecture of the neuromuscular system, and video recording of dynamic events such as spontaneous muscle fiber contraction. Second harmonic generation was combined with vital dyes and fluorescent-coupled molecules. Skin pigmentation, although limiting, did not prevent intravital imaging. Using this versatile toolbox on the Mtm1 knockout mouse, a model for myotubular myopathy which is a severe congenital myopathy in human, we identified several hallmarks of the disease such as defects in fiber size and neuromuscular junction shape. Intravital imaging of the neuromuscular system paves the way for the follow-up of disease progression or/and disease amelioration upon therapeutic tests. It has also the potential to reduce the number of animals needed to reach scientific conclusions.
Collapse
Affiliation(s)
- Luc Mercier
- Inserm U1109, MN3T, Strasbourg, France; Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; LabEx Medalis, Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Collège de France, Chaire de Génétique Humaine, Illkirch, France
| | - Nina Fekonja
- Inserm U1109, MN3T, Strasbourg, France; LabEx Medalis, Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Guillaume Allio
- Inserm U1109, MN3T, Strasbourg, France; LabEx Medalis, Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Yves Lutz
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
| | - Marc Koch
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
| | - Jacky G Goetz
- Inserm U1109, MN3T, Strasbourg, France; LabEx Medalis, Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Collège de France, Chaire de Génétique Humaine, Illkirch, France
| |
Collapse
|