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Marsh EB, Snyder-Warwick AK, Mackinnon SE, Wood MD. Interpretation of Data from Translational Rodent Nerve Injury and Repair Models. Hand Clin 2024; 40:429-440. [PMID: 38972687 PMCID: PMC11228394 DOI: 10.1016/j.hcl.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
This article highlights the use of rodents as preclinical models to evaluate the management of nerve injuries, describing the pitfalls and value from rodent nerve injury and regeneration outcomes, as well as treatments derived from these rodent models. The anatomic structure, size, and cellular and molecular differences and similarities between rodent and human nerves are summarized. Specific examples of success and failure when assessing outcome metrics are presented for context. Evidence for translation to clinical practice includes the topics of electrical stimulation, Tacrolimus (FK506), and acellular nerve allografts.
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Affiliation(s)
- Evan B Marsh
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Alison K Snyder-Warwick
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Susan E Mackinnon
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Matthew D Wood
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA.
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2
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Vanický I, Blaško J, Tomori Z, Michalová Z, Székiová E. Rat ventral caudal nerve as a model for long distance regeneration. IBRO Neurosci Rep 2024; 16:476-484. [PMID: 39007082 PMCID: PMC11240296 DOI: 10.1016/j.ibneur.2024.03.008] [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: 11/27/2023] [Accepted: 03/15/2024] [Indexed: 07/16/2024] Open
Abstract
In the rat, tail nerves are the longest peripheral nerves in their body. We suggest that ventral caudal nerve (VCN) may serve as a model for studying nerve injury and long distance regeneration. For this purpose, we have studied the anatomy and morphometry of the VCN in control animals. 10 cm long segment of the VCN was removed, and transversal sections were collected at 10 mm distances. The myelinated axons were counted, and the series of data were used to characterize the craniocaudal tapering of the nerve. In a separate group of animals, retrograde tracing with Fluorogold was used to localize and quantitate the spinal neurons projecting their axons into the VCN. After complete nerve transection, the time course of histopathological changes in the distal segment was studied. The primary goal was to define the time needed for axonal disintegration. In later periods, axonal debris removal and rearrangement of tissue elements was documented. After compression injury (axonotmesis), Wallerian degeneration was followed by spontaneous regeneration of axons. We show that the growing axons will span the 10 cm distance within 4-8 weeks. After different survival periods, the numbers of regenerating axons were counted at 10 mm distances. These data were used to characterize the dynamics of axonal regeneration during 4 months' survival period. In the present study we show that axonal regeneration across 10 cm distance can be studied and quantitatively analyzed in a small laboratory animal.
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Affiliation(s)
- Ivo Vanický
- Institute of Neurobiology Biomedical Research Center Slovak Academy of Sciences, Šoltésovej 4, Košice 04001, Slovakia
| | - Juraj Blaško
- Institute of Neurobiology Biomedical Research Center Slovak Academy of Sciences, Šoltésovej 4, Košice 04001, Slovakia
| | - Zoltán Tomori
- Institute of Experimental Physics Slovak Academy of Sciences, Watsonova 47, Košice 04001, Slovakia
| | - Zuzana Michalová
- Institute of Neurobiology Biomedical Research Center Slovak Academy of Sciences, Šoltésovej 4, Košice 04001, Slovakia
| | - Eva Székiová
- Institute of Neurobiology Biomedical Research Center Slovak Academy of Sciences, Šoltésovej 4, Košice 04001, Slovakia
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3
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Repair of Long Nerve Defects with a New Decellularized Nerve Graft in Rats and in Sheep. Cells 2022; 11:cells11244074. [PMID: 36552838 PMCID: PMC9777287 DOI: 10.3390/cells11244074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/30/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Decellularized nerve allografts (DC) are an alternative to autografts (AG) for repairing severe peripheral nerve injuries. We have assessed a new DC provided by VERIGRAFT. The decellularization procedure completely removed cellularity while preserving the extracellular matrix. We first assessed the DC in a 15 mm gap in the sciatic nerve of rats, showing slightly delayed but effective regeneration. Then, we assayed the DC in a 70 mm gap in the peroneal nerve of sheep compared with AG. Evaluation of nerve regeneration and functional recovery was performed by clinical, electrophysiology and ultrasound tests. No significant differences were found in functional recovery between groups of sheep. Histology showed a preserved fascicular structure in the AG while in the DC grafts regenerated axons were grouped in small units. In conclusion, the DC was permissive for axonal regeneration and allowed to repair a 70 mm long gap in the sheep nerve.
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González Rodríguez A, González Porto SA, Comellas Melero N, Arufe MC. Acellular nerve graft enriched with mesenchymal stem cells in the transfer of the phrenic nerve to the musculocutaneous nerve in a C5-C6 brachial plexus avulsion in a rat model. Microsurgery 2022; 42:57-65. [PMID: 34661312 DOI: 10.1002/micr.30829] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/14/2021] [Accepted: 09/17/2021] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Phrenic nerve transfer has been shown to achieve good nerve regeneration in brachial plexus avulsion. Acellular nerve allografts (ANAs) showed inferior results to autografts, which is why its use with mesenchymal stem cells (MSCs) is currently being studied. The aim is to study the effect of BM-MSCs associated with ANAs in a rat model of phrenic nerve transfer to the musculocutaneous nerve in a C5-C6 avulsion. MATERIAL AND METHODS 42 Wistar-Lewis rats underwent a C5-C6 lesion in the right forelimb by excising a 3 mm segment from both roots, followed by a phrenic nerve transfer to the musculocutaneous nerve associated with the interposition of a three types of nerve graft (randomly distributed): control (autograft) group (n = 12), ANAs group (n = 12), and ANAs + BM-MSCs group (n = 18) After 12 weeks, amplitude and latency of the NAP and the compound motor action potential (CMAP) were measured. Biceps muscles were studied by histological analysis and nerve grafts by electron microscopy and fluorescence analysis. RESULTS Statistically significant reductions were found in latency of the CMAP between groups control (2.48 ± 0.47 ms) and experimental (ANAs: 4.38 ± 0.78 ms, ANAs + BM-MSCs: 4.08 ± 0.85 ms) and increases in the amplitude of the CMAP between groups control (0.04388 ± 0.02 V) and ANAs + BM-MSCs (0.02275 ± 0.02 V), as well as in the thickness of the myelin sheath between groups control (0.81 ± 0.07 μm) and experimental (ANAs: 0.72 ± 0.08 μm, ANAs + BM-MSCs: 0.72 ± 0.07 μm) and in the area of the myelin sheath between groups control (13.09 ± 2.67 μm2 ) and ANAs (10.01 ± 2.97 μm2 ) (p < .05). No statistically significant differences have been found between groups ANAs and ANAs + BM-MSCs. CONCLUSIONS This study presents a model for the study of lesions of the upper trunk and validates the autologous graft as the gold standard.
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Affiliation(s)
- Alba González Rodríguez
- Research Group on Cell Therapy and Regenerative Medicine; Physiotherapy, Biomedical Sciences and Medicine Department, A Coruña University (CHUAC. INIBIC), A Coruña, Spain
| | | | - Nerea Comellas Melero
- Research Group on Cell Therapy and Regenerative Medicine; Physiotherapy, Biomedical Sciences and Medicine Department, A Coruña University (CHUAC. INIBIC), A Coruña, Spain
| | - María C Arufe
- Research Group on Cell Therapy and Regenerative Medicine; Physiotherapy, Biomedical Sciences and Medicine Department, A Coruña University (CHUAC. INIBIC), A Coruña, Spain
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5
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Burrell JC, Browne KD, Dutton JL, Laimo FA, Das S, Brown DP, Roberts S, Petrov D, Ali Z, Ledebur HC, Rosen JM, Kaplan HM, Wolf JA, Smith DH, Chen HI, Cullen DK. A Porcine Model of Peripheral Nerve Injury Enabling Ultra-Long Regenerative Distances: Surgical Approach, Recovery Kinetics, and Clinical Relevance. Neurosurgery 2021; 87:833-846. [PMID: 32392341 DOI: 10.1093/neuros/nyaa106] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 02/11/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Millions of Americans experience residual deficits from traumatic peripheral nerve injury (PNI). Despite advancements in surgical technique, repair typically results in poor functional outcomes due to prolonged periods of denervation resulting from long regenerative distances coupled with slow rates of axonal regeneration. Novel surgical solutions require valid preclinical models that adequately replicate the key challenges of clinical PNI. OBJECTIVE To develop a preclinical model of PNI in swine that addresses 2 challenging, clinically relevant PNI scenarios: long segmental defects (≥5 cm) and ultra-long regenerative distances (20-27 cm). Thus, we aim to demonstrate that a porcine model of major PNI is suitable as a potential framework to evaluate novel regenerative strategies prior to clinical deployment. METHODS A 5-cm-long common peroneal nerve or deep peroneal nerve injury was repaired using a saphenous nerve or sural nerve autograft, respectively. Histological and electrophysiological assessments were performed at 9 to 12 mo post repair to evaluate nerve regeneration and functional recovery. Relevant anatomy, surgical approach, and functional/histological outcomes were characterized for both repair techniques. RESULTS Axons regenerated across the repair zone and were identified in the distal stump. Electrophysiological recordings confirmed these findings and suggested regenerating axons reinnervated target muscles. CONCLUSION The models presented herein provide opportunities to investigate peripheral nerve regeneration using different nerves tailored for specific mechanisms of interest, such as nerve modality (motor, sensory, and mixed fiber composition), injury length (short/long gap), and total regenerative distance (proximal/distal injury).
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Affiliation(s)
- Justin C Burrell
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania.,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kevin D Browne
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - John L Dutton
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Franco A Laimo
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Suradip Das
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Daniel P Brown
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Sanford Roberts
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Dmitriy Petrov
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Zarina Ali
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Joseph M Rosen
- Division of Plastic Surgery, Dartmouth-Hitchcock Medical Center, Dartmouth College, Lebanon, New Hampshire
| | - Hilton M Kaplan
- New Jersey Center for Biomaterials, Rutgers University, New Brunswick, New Jersey
| | - John A Wolf
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Douglas H Smith
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Axonova Medical, Philadelphia, Pennsylvania
| | - H Isaac Chen
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - D Kacy Cullen
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania.,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania.,Axonova Medical, Philadelphia, Pennsylvania
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Zare EN, Padil VV, Mokhtari B, Venkateshaiah A, Wacławek S, Černík M, Tay FR, Varma RS, Makvandi P. Advances in biogenically synthesized shaped metal- and carbon-based nanoarchitectures and their medicinal applications. Adv Colloid Interface Sci 2020; 283:102236. [PMID: 32829011 DOI: 10.1016/j.cis.2020.102236] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 08/06/2020] [Indexed: 02/08/2023]
Abstract
Non-spherical metal-based and carbon-based nanostructures have found applications in every facet of scientific endeavors, including engineering and biomedical fields. These nanostructures attract attention because of their biocompatibility and negligible cytotoxicity. Chemical and physical methods have been used for synthesizing earlier generations of metal-based and carbon-based nanostructures with variable architectures, including nanorods, nanowires, nanodots and nanosheets. However, these synthesis strategies utilize organic passivators which are toxic to the environment and the human body. Biogenic synthesis of nanoparticles is becoming increasing popular because of the necessity to develop eco-friendly and non-toxic strategies. Nanoparticles synthesized by natural compounds have immense potential in the biomedical arena. The present review focuses on plant-mediated synthesis of metal-based and carbon-based non-spherical nanoarchitectures and the role of green synthesis in improving their activities for biomedical applications.
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Shafer B, Welle C, Vasudevan S. A rat model for assessing the long-term safety and performance of peripheral nerve electrode arrays. J Neurosci Methods 2019; 328:108437. [PMID: 31526764 DOI: 10.1016/j.jneumeth.2019.108437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 08/05/2019] [Accepted: 09/13/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND High-resolution peripheral nerve interfaces (PNIs) can provide amputees with intuitive motor control and sensory feedback. Current PNIs are limited by early device failure and suboptimal long-term stability. The present study aims to incorporate functional assessment into an in vivo test platform to assess the long-term safety and performance of PNIs for recording and stimulation. NEW METHODS Utah electrode arrays (EA) were implanted in the rat sciatic nerve along with electromyography wires in the gastrocnemius and tibialis anterior. Cranial EEG screws were implanted in the somatosensory cortex for 12 weeks. Spontaneous neural activity was recorded using the implanted EA and stimulation-induced activity was monitored throughout the experiment. The impedance of each electrode was measured, and nerve function tests were conducted throughout the EA lifetime. Post-hoc safety assessments included scanning electron microscopy (SEM) of the EA and nerve histomorphometric analysis. RESULTS EA recordings were stable, and stimulation with EA elicited somatosensory evoked potentials and muscle contractions. Motor and sensory function tests indicated minimal deficits. Histomorphometric analysis indicated changes in nerve microstructure. SEM indicated EA-tip fracture, while lead wire breakage primarily caused device failure. COMPARISON WITH EXISTING METHODS We improved our prior platform with the addition of functional assessments of sensory pathways, a robust EMG array design to increase device longevity, and quantitative analysis of nerve microstructure. CONCLUSION We present a test platform for long-term assessment of peripheral nerve interfaces for stimulation and recording. Using this platform, we demonstrate recording and stimulation with minimal impact on nerve function, while EA lead wire breakage and tip fracture could limit long-term device use.
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Affiliation(s)
- Benjamin Shafer
- U. S. Food and Drug Administration, Center for Devices and Radiological Health (CDRH), Office of Science and Engineering Laboratory (OSEL), Division of Biomedical Physics (DBP), Silver Spring, MD, USA
| | - Cristin Welle
- University of Colorado, Anschutz Medical Campus, Departments of Neurosurgery and Bioengineering, Aurora, CO, 80045, USA
| | - Srikanth Vasudevan
- U. S. Food and Drug Administration, Center for Devices and Radiological Health (CDRH), Office of Science and Engineering Laboratory (OSEL), Division of Biomedical Physics (DBP), Silver Spring, MD, USA.
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8
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Carvalho CR, Silva-Correia J, Oliveira JM, Reis RL. Nanotechnology in peripheral nerve repair and reconstruction. Adv Drug Deliv Rev 2019; 148:308-343. [PMID: 30639255 DOI: 10.1016/j.addr.2019.01.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/20/2018] [Accepted: 01/05/2019] [Indexed: 02/07/2023]
Affiliation(s)
- Cristiana R Carvalho
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017, Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, AvePark, 4805-017 Barco, Guimarães, Portugal
| | - Joana Silva-Correia
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017, Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Joaquim M Oliveira
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017, Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, AvePark, 4805-017 Barco, Guimarães, Portugal
| | - Rui L Reis
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017, Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, AvePark, 4805-017 Barco, Guimarães, Portugal.
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Vasudevan S, Vo J, Shafer B, Nam AS, Vakoc BJ, Hammer DX. Toward optical coherence tomography angiography-based biomarkers to assess the safety of peripheral nerve electrostimulation. J Neural Eng 2019; 16:036024. [PMID: 30917357 PMCID: PMC6583899 DOI: 10.1088/1741-2552/ab1405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Peripheral nerves serve as a link between the central nervous system and its targets. Altering peripheral nerve activity through targeted electrical stimulation is being investigated as a therapy for modulating end organ function. To support rapid advancement in the field, novel approaches to predict and prevent nerve injury resulting from electrical stimulation must be developed to overcome the limitations of traditional histological methods. The present study aims to develop an optical imaging-based approach for real-time assessment of peripheral nerve injury associated with electrical stimulation. APPROACH We developed an optical coherence tomography (OCT) angiography system and a 3D printed stimulating nerve stabilizer (sNS) to assess the real-time microvascular and blood flow changes associated with electrical stimulation of peripheral nerves. We then compared the microvascular changes with established nerve function analysis and immunohistochemistry to correlate changes with nerve injury. MAIN RESULTS Electrical stimulation of peripheral nerves has a direct influence on vessel diameter and capillary flow. The stimulation used in this study did not alter motor function significantly, but a delayed onset of mechanical allodynia at lower thresholds was observed using a sensory function test. Immunohistochemical analysis pointed to an increased number of macrophages within nerve fascicles and axon sprouting potentially related to nerve injury. SIGNIFICANCE This study is the first to demonstrate the ability to image peripheral nerve microvasculature changes during electrical stimulation. This expands the knowledge in the field and can be used to develop potential biomarkers to predict nerve injury resulting from electrical stimulation.
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Affiliation(s)
- Srikanth Vasudevan
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
| | - Jesse Vo
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States of America
| | - Benjamin Shafer
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
| | - Ahhyun S Nam
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, United States of America
| | - Benjamin J Vakoc
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, United States of America
| | - Daniel X Hammer
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
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Straka MM, Shafer B, Vasudevan S, Welle C, Rieth L. Characterizing Longitudinal Changes in the Impedance Spectra of In-Vivo Peripheral Nerve Electrodes. MICROMACHINES 2018; 9:mi9110587. [PMID: 30424513 PMCID: PMC6266965 DOI: 10.3390/mi9110587] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 11/02/2018] [Accepted: 11/05/2018] [Indexed: 12/18/2022]
Abstract
Characterizing the aging processes of electrodes in vivo is essential in order to elucidate the changes of the electrode–tissue interface and the device. However, commonly used impedance measurements at 1 kHz are insufficient for determining electrode viability, with measurements being prone to false positives. We implanted cohorts of five iridium oxide (IrOx) and six platinum (Pt) Utah arrays into the sciatic nerve of rats, and collected the electrochemical impedance spectroscopy (EIS) up to 12 weeks or until array failure. We developed a method to classify the shapes of the magnitude and phase spectra, and correlated the classifications to circuit models and electrochemical processes at the interface likely responsible. We found categories of EIS characteristic of iridium oxide tip metallization, platinum tip metallization, tip metal degradation, encapsulation degradation, and wire breakage in the lead. We also fitted the impedance spectra as features to a fine-Gaussian support vector machine (SVM) algorithm for both IrOx and Pt tipped arrays, with a prediction accuracy for categories of 95% and 99%, respectively. Together, this suggests that these simple and computationally efficient algorithms are sufficient to explain the majority of variance across a wide range of EIS data describing Utah arrays. These categories were assessed over time, providing insights into the degradation and failure mechanisms for both the electrode–tissue interface and wire bundle. Methods developed in this study will allow for a better understanding of how EIS can characterize the physical changes to electrodes in vivo.
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Affiliation(s)
- Malgorzata M Straka
- Center for Bioelectronic Medicine, Feinstein Institute for Medical Research, Northwell Health, Manhasset, NY 11030, USA.
| | - Benjamin Shafer
- U.S. Food and Drug Administration, Center for Devices and Radiological Health (CDRH), Office of Science and Engineering Laboratory (OSEL), Division of Biomedical Physics (DBP), Silver Spring, MD 20993, USA.
| | - Srikanth Vasudevan
- U.S. Food and Drug Administration, Center for Devices and Radiological Health (CDRH), Office of Science and Engineering Laboratory (OSEL), Division of Biomedical Physics (DBP), Silver Spring, MD 20993, USA.
| | - Cristin Welle
- Departments of Neurosurgery and Bioengineering, University of Colorado, Aurora, CO 80045, USA.
| | - Loren Rieth
- Center for Bioelectronic Medicine, Feinstein Institute for Medical Research, Northwell Health, Manhasset, NY 11030, USA.
- Departments of Electrical Engineering and Bioengineering, University of Utah, Salt Lake City, UT 84112, USA.
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Analysis of regeneration- and myelination-associated proteins in human neuroma in continuity and discontinuity. Acta Neurochir (Wien) 2018; 160:1269-1281. [PMID: 29656327 DOI: 10.1007/s00701-018-3544-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/04/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND Neuromas are pathologic nerve distensions caused by a nerve's response to trauma, resulting in a dysfunctional to non-functional nerve. Depending on the severance of the affected nerve, the resulting neuroma can be differentiated into continuous and stump neuroma. While neuroma formation has been investigated in animal models with enormous regenerative capacity, the search for differences in human response to nerve trauma on a molecular level ultimately seeks to identify reasons for functionally successful versus unsuccessful regeneration after peripheral nerve trauma in man. METHODS In the present study, the regenerative potential of axons and the capability of Schwann cells (SC) to remyelinate regenerating axons was quantitatively and segmentally analyzed and compared within human neuroma in-continuity and discontinuity. RESULTS For the stump neuroma and the neuroma in-continuity, there was a significant reduction of the total number of axons (86% stump neuroma and 91% neuroma in-continuity) from the proximal to the distal part of the neuroma, while the amount of fibrotic tissue increased, respectively. Labeling the myelin sheath of regenerating axons revealed a remyelination of regenerating axons by SCs in both neuroma types. The segmented analysis showed no distinct alterations in the number and spatial distribution of regenerating, mature, and myelinated axons between continuous and discontinuous neuroma. CONCLUSIONS The quantitative and segmented analysis showed no distinct alterations in the number and spatial distribution of regenerating, mature, and myelinated axons between continuous and discontinuous neuroma, while the extensive expression of Gap43 in up to 55% of the human neuroma axons underlines their regenerative capacity independent of whether the neuroma is in continuity or discontinuity. Remyelination of Gap43-positive axons suggests that the capability of SCs to remyelinate regenerating axons is preserved in neuroma tissue.
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Anand S, Desai V, Alsmadi N, Kanneganti A, Nguyen DHT, Tran M, Patil L, Vasudevan S, Xu C, Hong Y, Cheng J, Keefer E, Romero-Ortega MI. Asymmetric Sensory-Motor Regeneration of Transected Peripheral Nerves Using Molecular Guidance Cues. Sci Rep 2017; 7:14323. [PMID: 29085079 PMCID: PMC5662603 DOI: 10.1038/s41598-017-14331-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/06/2017] [Indexed: 11/22/2022] Open
Abstract
Neural interfaces are designed to decode motor intent and evoke sensory precepts in amputees. In peripheral nerves, recording movement intent is challenging because motor axons are only a small fraction compared to sensory fibers and are heterogeneously mixed particularly at proximal levels. We previously reported that pain and myelinated axons regenerating through a Y-shaped nerve guide with sealed ends, can be modulated by luminar release of nerve growth factor (NGF) and neurotrophin-3 (NT-3), respectively. Here, we evaluate the differential potency of NGF, glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), pleiotrophin (PTN), and NT-3 in asymmetrically guiding the regeneration of sensory and motor neurons. We report that, in the absence of distal target organs, molecular guidance cues can mediate the growth of electrically conductive fascicles with normal microanatomy. Compared to Y-tube compartments with bovine serum albumin (BSA), GDNF and NGF increased the motor and sensory axon content, respectively. In addition, the sensory to motor ratio was significantly increased by PTN (12.7:1) when compared to a BDNF + GDNF choice. The differential content of motor and sensory axons modulated by selective guidance cues may provide a strategy to better define axon types in peripheral nerve interfaces.
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Affiliation(s)
- Sanjay Anand
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Vidhi Desai
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Blvd, Arlington, Texas, 76010, USA
| | - Nesreen Alsmadi
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Aswini Kanneganti
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Dianna Huyen-Tram Nguyen
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Blvd, Arlington, Texas, 76010, USA
| | - Martin Tran
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Blvd, Arlington, Texas, 76010, USA
| | - Lokesh Patil
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Srikanth Vasudevan
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Cancan Xu
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Blvd, Arlington, Texas, 76010, USA
| | - Yi Hong
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Blvd, Arlington, Texas, 76010, USA
| | - Jonathan Cheng
- Department of Plastic Surgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA
| | - Edward Keefer
- Nerves Incorporated, P.O. Box 141295, Dallas, TX 75214, USA
| | - Mario I Romero-Ortega
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA.
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Vasudevan S, Patel K, Welle C. Rodent model for assessing the long term safety and performance of peripheral nerve recording electrodes. J Neural Eng 2016; 14:016008. [PMID: 27934777 DOI: 10.1088/1741-2552/14/1/016008] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE In the US alone, there are approximately 185 000 cases of limb amputation annually, which can reduce the quality of life for those individuals. Current prosthesis technology could be improved by access to signals from the nervous system for intuitive prosthesis control. After amputation, residual peripheral nerves continue to convey motor signals and electrical stimulation of these nerves can elicit sensory percepts. However, current technology for extracting information directly from peripheral nerves has limited chronic reliability, and novel approaches must be vetted to ensure safe long-term use. The present study aims to optimize methods to establish a test platform using rodent model to assess the long term safety and performance of electrode interfaces implanted in the peripheral nerves. APPROACH Floating Microelectrode Arrays (FMA, Microprobes for Life Sciences) were implanted into the rodent sciatic nerve. Weekly in vivo recordings and impedance measurements were performed in animals to assess performance and physical integrity of electrodes. Motor (walking track analysis) and sensory (Von Frey) function tests were used to assess change in nerve function due to the implant. Following the terminal recording session, the nerve was explanted and the health of axons, myelin and surrounding tissues were assessed using immunohistochemistry (IHC). The explanted electrodes were visualized under high magnification using scanning electrode microscopy (SEM) to observe any physical damage. MAIN RESULTS Recordings of axonal action potentials demonstrated notable session-to-session variability. Impedance of the electrodes increased upon implantation and displayed relative stability until electrode failure. Initial deficits in motor function recovered by 2 weeks, while sensory deficits persisted through 6 weeks of assessment. The primary cause of failure was identified as lead wire breakage in all of animals. IHC indicated myelinated and unmyelinated axons near the implanted electrode shanks, along with dense cellular accumulations near the implant site. Scanning electron microscopy (SEM) showed alterations of the electrode insulation and deformation of electrode shanks. SIGNIFICANCE We describe a comprehensive testing platform with applicability to electrodes that record from the peripheral nerves. This study assesses the long term safety and performance of electrodes in the peripheral nerves using a rodent model. Under this animal test platform, FMA electrodes record single unit action potentials but have limited chronic reliability due to structural weaknesses. Future work will apply these methods to other commercially-available and novel peripheral electrode technologies.
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Affiliation(s)
- Srikanth Vasudevan
- Division of Biomedical Physics, Office of Science and Engineering Laboratory, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD, USA
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14
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Kaplan HM, Mishra P, Kohn J. The overwhelming use of rat models in nerve regeneration research may compromise designs of nerve guidance conduits for humans. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:226. [PMID: 26296419 PMCID: PMC4545171 DOI: 10.1007/s10856-015-5558-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 08/13/2015] [Indexed: 06/04/2023]
Abstract
Rats are not the best model for the evolving complexities we face in designing nerve repair strategies today. The development of effective nerve guidance conduits for nerve regeneration is severely limited by the rat sciatic nerve model as the almost exclusive research model in academia. An immense effort is underway to develop an alternative to autologous nerve grafts for the repair of nerve defects, aiming particularly at larger gap repairs of 5-30 cm or more. This must involve combinations of ever more complex components, which in the vast majority of cases begin their testing in the rat model. Three major problems are at play: (1) The majority of nerve regeneration data is now being generated in the rat, which is likely to skew treatment outcomes and lead to inappropriate evaluation of risks and benefits. (2) The rat is a particularly poor model for the repair of human critical gap defects due to both its small size and its species-specific neurobiological regenerative profile. (3) Translation from rat to human has proven unreliable for nerve regeneration, as for many other applications. We explore each of these facets and their implications, in order to highlight the need for appropriate awareness in animal model selection when translating nerve regeneration modalities of ever-increasing complexity-from relatively simple devices to drug-device-biologic combinations.
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Affiliation(s)
- Hilton M. Kaplan
- New Jersey Center for Biomaterials, Rutgers University, 145 Bevier Road, LSB-101, Piscataway, NJ 08854 USA
| | - Prakhar Mishra
- New Jersey Center for Biomaterials, Rutgers University, 145 Bevier Road, LSB-101, Piscataway, NJ 08854 USA
| | - Joachim Kohn
- New Jersey Center for Biomaterials, Rutgers University, 145 Bevier Road, LSB-101, Piscataway, NJ 08854 USA
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Detergent-free Decellularized Nerve Grafts for Long-gap Peripheral Nerve Reconstruction. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2014; 2:e201. [PMID: 25426384 PMCID: PMC4236362 DOI: 10.1097/gox.0000000000000118] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 03/31/2014] [Indexed: 12/12/2022]
Abstract
Background: Long-gap peripheral nerve defects arising from tumor, trauma, or birth-related injuries requiring nerve reconstruction are currently treated using nerve autografts and nerve allografts. Autografts are associated with limited supply and donor-site morbidity. Allografts require administration of transient immunosuppressants, which has substantial associated risks. To overcome these limitations, we investigated the use of detergent-free decellularized nerve grafts to reconstruct long-gap nerve defects in a rodent model and compared it with existing detergent processing techniques. Methods: Nerve grafts were harvested from the sciatic nerves of 9 donor rats. Twenty-four recipient rats were divided into 4 groups (6 animals per group): (1) nerve grafts (NG, positive control), (2) detergent-free decellularized (DFD) grafts, (3) detergent decellularized grafts, and (4) silicone tube conduits (negative control). Each recipient rat had a 3.5-cm graft or conduit sutured across a sciatic nerve transection injury. All animals were harvested at 12 weeks postimplantation for functional muscle analysis and nerve histomorphometry. Results: Histomorphometry results indicated maximum growth in NG when compared with other groups. DFD and detergent decellularized groups showed comparable regeneration at 12 weeks. Silicone tube group showed no regeneration as expected. Muscle force data indicated functional recovery in NG and DFD groups only. Conclusions: This study describes a detergent-free nerve decellularization technique for reconstruction of long-gap nerve injuries. We compared DFD grafts with an established detergent processing technique and found that DFD nerve grafts are successful in promoting regeneration across long-gap peripheral nerve defects as an alternative to existing strategies.
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