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Annals of Anatomy = Anatomischer... Jul 2011Peripheral nerve injury is a common casualty and although peripheral nerve fibers retain a considerable regeneration potential also in the adult, recovery is usually... (Review)
Review
Peripheral nerve injury is a common casualty and although peripheral nerve fibers retain a considerable regeneration potential also in the adult, recovery is usually rather poor, especially in case of large nerve defects. The aim of this paper is to address the perspectives in regeneration and tissue engineering after peripheral nerve injury by reviewing the relevant experimental studies in animal models. After a brief overview of the morphological changes related to peripheral nerve injury and regeneration, the paper will address the evolution of peripheral nerve tissue engineering with special focus on transplantation strategies, from organs and tissues to cells and genes, that can be carried out, particularly in case of severe nerve lesions with substance loss. Finally, the need for integrated research which goes beyond therapeutic strategies based on single approaches is emphasized, and the importance of bringing together the various complimentary disciplines which can contribute to the definition of effective new strategies for regenerating the injured peripheral nerve is outlined.
Topics: Animals; Humans; Microsurgery; Models, Animal; Nerve Regeneration; Peripheral Nerve Injuries; Peripheral Nerves; Publishing; Rats; Tissue Engineering; Tissue Transplantation
PubMed: 21474294
DOI: 10.1016/j.aanat.2011.03.001 -
The Anatomical Record Aug 2001Eleven thousand Americans each year are affected by paralysis, a devastating injury that possesses associated annual costs of $7 billion (American Paralysis Association,... (Review)
Review
Eleven thousand Americans each year are affected by paralysis, a devastating injury that possesses associated annual costs of $7 billion (American Paralysis Association, 1997). Currently, there is no effective treatment for damage to the central nervous system (CNS), and acute spinal cord injury has been extraordinarily resistant to treatment. Compared to spinal cord injury, damage to peripheral nerves is considerably more common. In 1995, there were in excess of 50,000 peripheral nerve repair procedures performed. (National Center for Health Statistics based on Classification of Diseases, 9th Revision, Clinical Modification for the following categories: ICD-9 CM Code: 04.3, 04.5, 04.6, 04.7). These data, however, probably underestimate the number of nerve injuries appreciated, as not all surgical or traumatic lesions can be repaired. Further, intraabodominal procedures may add to the number of neurologic injuries by damage to the autonomic system through tumor resection. For example, studies assessing the outcome of impotency following radical prostatectomy demonstrated 212 of 503 previously potent men (42%) suffered impotency when partial or complete resection of one or both cavernosal nerve(s). This impotency rate decreased to 24% when the nerves were left intact (Quinlan et al., J. Urol. 1991;145:380-383; J. Urol. 1991;145:998-1002).
Topics: Adult; Animals; Bioartificial Organs; Biomedical Engineering; Humans; Male; Nerve Regeneration; Nerve Transfer; Peripheral Nerve Injuries; Peripheral Nerves; Sural Nerve
PubMed: 11500817
DOI: 10.1002/ar.1120 -
Journal of Neuroinflammation Apr 2022Macrophages are present in all mammalian tissues and coexist with various cell types in order to respond to different environmental cues. However, the role of these... (Review)
Review
Macrophages are present in all mammalian tissues and coexist with various cell types in order to respond to different environmental cues. However, the role of these cells has been underestimated in the context of peripheral nerve damage. More importantly, macrophages display divergent characteristics, associated with their origin, and in response to the modulatory effects of their microenvironment. Interestingly, the advent of new techniques such as fate mapping and single-cell transcriptomics and their synergistic use has helped characterize in detail the origin and fate of tissue-resident macrophages in the peripheral nervous system (PNS). Furthermore, these techniques have allowed a better understanding of their functions from simple homeostatic supervisors to chief regulators in peripheral neuropathies. In this review, we summarize the latest knowledge about macrophage ontogeny, function and tissue identity, with a particular focus on PNS-associated cells, as well as their interaction with reactive oxygen species under physiological and pathological conditions. We then revisit the process of Wallerian degeneration, describing the events accompanying axon degeneration, Schwann cell activation and most importantly, macrophage recruitment to the site of injury. Finally, we review these processes in light of internal and external insults to peripheral nerves leading to peripheral neuropathies, the involvement of macrophages and the potential benefit of the targeting of specific macrophages for the alleviation of functional defects in the PNS.
Topics: Animals; Macrophages; Mammals; Peripheral Nerve Injuries; Peripheral Nerves; Schwann Cells; Wallerian Degeneration
PubMed: 35429971
DOI: 10.1186/s12974-022-02454-6 -
Tissue Engineering. Part B, Reviews Feb 2012Currently, surgical treatments for peripheral nerve injury are less than satisfactory. The gold standard of treatment for peripheral nerve gaps >5 mm is the autologous... (Review)
Review
Currently, surgical treatments for peripheral nerve injury are less than satisfactory. The gold standard of treatment for peripheral nerve gaps >5 mm is the autologous nerve graft; however, this treatment is associated with a variety of clinical complications, such as donor site morbidity, limited availability, nerve site mismatch, and the formation of neuromas. Despite many recent advances in the field, clinical studies implementing the use of artificial nerve guides have yielded results that are yet to surpass those of autografts. Thus, the development of a nerve guidance conduit, which could match the effectiveness of the autologous nerve graft, would be beneficial to the field of peripheral nerve surgery. Design strategies to improve surgical outcomes have included the development of biopolymers and synthetic polymers as primary scaffolds with tailored mechanical and physical properties, luminal "fillers" such as laminin and fibronectin as secondary internal scaffolds, surface micropatterning, stem cell inclusion, and controlled release of neurotrophic factors. The current article highlights approaches to peripheral nerve repair through a channel or conduit, implementing chemical and physical growth and guidance cues to direct that repair process.
Topics: Animals; Biocompatible Materials; Guided Tissue Regeneration; Humans; Nerve Regeneration; Peripheral Nerves; Tissue Scaffolds
PubMed: 21812591
DOI: 10.1089/ten.TEB.2011.0240 -
Gut Microbes 2024Gut microbiota is responsible for essential functions in human health. Several communication axes between gut microbiota and other organs via neural, endocrine, and...
Gut microbiota is responsible for essential functions in human health. Several communication axes between gut microbiota and other organs via neural, endocrine, and immune pathways have been described, and perturbation of gut microbiota composition has been implicated in the onset and progression of an emerging number of diseases. Here, we analyzed peripheral nerves, dorsal root ganglia (DRG), and skeletal muscles of neonatal and young adult mice with the following gut microbiota status: a) germ-free (GF), b) gnotobiotic, selectively colonized with 12 specific gut bacterial strains (Oligo-Mouse-Microbiota, OMM12), or c) natural complex gut microbiota (CGM). Stereological and morphometric analyses revealed that the absence of gut microbiota impairs the development of somatic median nerves, resulting in smaller diameter and hypermyelinated axons, as well as in smaller unmyelinated fibers. Accordingly, DRG and sciatic nerve transcriptomic analyses highlighted a panel of differentially expressed developmental and myelination genes. Interestingly, the type III isoform of Neuregulin1 (NRG1), known to be a neuronal signal essential for Schwann cell myelination, was overexpressed in young adult GF mice, with consequent overexpression of the transcription factor Early Growth Response 2 (), a fundamental gene expressed by Schwann cells at the onset of myelination. Finally, GF status resulted in histologically atrophic skeletal muscles, impaired formation of neuromuscular junctions, and deregulated expression of related genes. In conclusion, we demonstrate for the first time a gut microbiota regulatory impact on proper development of the somatic peripheral nervous system and its functional connection to skeletal muscles, thus suggesting the existence of a novel 'Gut Microbiota-Peripheral Nervous System-axis.'
Topics: Animals; Gastrointestinal Microbiome; Neuromuscular Junction; Mice; Ganglia, Spinal; Germ-Free Life; Peripheral Nerves; Muscle, Skeletal; Mice, Inbred C57BL; Neuregulin-1; Male; Bacteria; Schwann Cells
PubMed: 38845453
DOI: 10.1080/19490976.2024.2363015 -
AJNR. American Journal of Neuroradiology Feb 2012High-resolution MRN is becoming increasingly available due to recent technical advancements, including higher magnetic field strengths (eg, 3T), 3D image acquisition,... (Review)
Review
High-resolution MRN is becoming increasingly available due to recent technical advancements, including higher magnetic field strengths (eg, 3T), 3D image acquisition, evolution of novel fat-suppression methods, and improved coil design. This review describes the MRN techniques for obtaining high-quality images of the peripheral nerves and their small branches and imaging findings in normal as well as injured nerves with relevant intraoperative correlations. Various microsurgical techniques in peripheral nerves, such as neurolysis, nerve repairs by using nerve grafts, and conduits are discussed, and MRN findings of surgically treated nerves are demonstrated.
Topics: Humans; Magnetic Resonance Imaging; Neuroradiography; Neurosurgical Procedures; Peripheral Nerves
PubMed: 21527571
DOI: 10.3174/ajnr.A2465 -
Journal of Vascular Research 2013The internal microenvironment in peripheral nerves is highly regulated in order to maintain normal axonal impulse transmission to or from the central nervous system. In... (Review)
Review
The internal microenvironment in peripheral nerves is highly regulated in order to maintain normal axonal impulse transmission to or from the central nervous system. In humans, this regulation is facilitated by specialized tight junction (TJ)-forming endoneurial microvascular endothelial cells and perineurial myofibroblasts that form multiple concentric layers around nerve fascicles. The endoneurial endothelial cells come in direct contact with circulating blood and, thus, can be considered the blood-nerve barrier (BNB). Studies on the molecular and biophysical properties of the human BNB in vivo or in situ are limited. Owing to the recent isolation of primary human endoneurial endothelial cells and the development of simian virus 40 large T-antigen immortalized cell lines, data are emerging on the structural and functional characteristics of these cells. These data aim to increase our understanding of how solutes, macromolecules, nutrients and hematogenous leukocytes gain access into or are restricted from the endoneurium of peripheral nerves. These concepts have clinical relevance in understanding normal peripheral nerve homeostasis, the response of peripheral nerves to external insult and stresses such as drugs and toxins and the pathogenesis of peripheral neuropathies. This review discusses current knowledge in this nascent and exciting field of microvascular biology.
Topics: Animals; Biological Transport; Biomarkers; Blood-Nerve Barrier; Capillary Permeability; Cells, Cultured; Electric Conductivity; Endothelial Cells; Homeostasis; Humans; Myofibroblasts; Peripheral Nerves; Tight Junctions
PubMed: 23839247
DOI: 10.1159/000353293 -
Minerva Anestesiologica Jan 2011Peripheral nerve injury is a rare complication of regional anesthesia. Intraneural injections were once considered harbingers of neural injury with practitioners... (Review)
Review
Peripheral nerve injury is a rare complication of regional anesthesia. Intraneural injections were once considered harbingers of neural injury with practitioners focusing on their avoidance. With ultrasound guidance, it is now possible to visualize the difference between perineural (outside the nerve), intraneural (below the epineurium), and intrafascicular (within the perineurium) injections and to determine their association with postoperative neurological complications. We also now have a better understanding of the multifactorial nature of neurologic injury based on the nerve anatomy, site of needle insertion, bevel type, location of the needle tip, pressure achieved during injection, and underlying patient factors. Using ultrasound guidance during nerve blocks has revealed that not all intraneural injections result in injury, and its use will continue to provide insight into the mechanism of anesthetic-related nerve injury.
Topics: Anesthetics, Local; Animals; Brachial Plexus Neuropathies; Dogs; Electric Stimulation; Equipment Design; Humans; Needles; Needlestick Injuries; Nerve Block; Peripheral Nerve Injuries; Peripheral Nerves; Postoperative Complications; Rabbits; Rats; Sciatic Nerve; Ultrasonography
PubMed: 21273966
DOI: No ID Found -
Radiologia 2020Imaging studies of peripheral nerves have increased considerably in the last ten years. In addition to the classical and still valid study by ultrasound, new... (Review)
Review
Imaging studies of peripheral nerves have increased considerably in the last ten years. In addition to the classical and still valid study by ultrasound, new neurographic techniques developed from conventional morphological sequences (including 3D isotropic studies with fat suppression) are making it possible to assess different peripheral nerves and plexuses, including small sensory and/or motor branches, with great precision. Diffusion-weighted sequences and diffusion tensor imaging have opened a new horizon in neurographic studies. This new approach provides morphological and functional information about the internal structure and pathophysiology of the peripheral nerves and diseases that involve them. This update reviews the different MR neurography techniques available for the study of the peripheral nerves, with special emphasis on new sequences based on diffusion.
Topics: Adult; Brachial Plexus; Diffusion Magnetic Resonance Imaging; Diffusion Tensor Imaging; Female; Humans; Lumbosacral Plexus; Magnetic Resonance Imaging; Male; Middle Aged; Peripheral Nerves; Peripheral Nervous System Diseases; Tomography, X-Ray Computed; Ultrasonography
PubMed: 31611009
DOI: 10.1016/j.rx.2019.06.005 -
Rhode Island Medical Journal (2013) Mar 2021Peripheral nerves are crucial to the motor and sensory function provided by our upper and lower extremities to our brain and spinal cord. Following trauma or illness,... (Review)
Review
Peripheral nerves are crucial to the motor and sensory function provided by our upper and lower extremities to our brain and spinal cord. Following trauma or illness, these nerves may be injured, leading to a loss of function that can be significantly debilitating. Fortunately, given the type of injury and under the right conditions, peripheral nerves can regenerate through well-coordinated biochemical processes. However, as individuals age, the ability for nerves to regenerate becomes less efficient, reducing nerve's potential for the nerve to return to its prior level of function. In this article, we review the research that has been conducted to illustrate the reasons for such a decline in regenerative capacity. In doing so, we explore the concept of inflammaging alongside aging-related impairments of the macrophage and Schwann cell during nerve regeneration.
Topics: Aging; Humans; Nerve Regeneration; Peripheral Nerves; Schwann Cells
PubMed: 33648318
DOI: No ID Found