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Background and Aims Methods Results Interpretation Peripheral nerve injuries often require bridging when direct repair is not feasible. Nerve autografts are the gold standard, but they can lead to donor site morbidity. Silk fibroin‐based nerve conduits, like the novel SILKBridge, offer a promising alternative. This pilot study evaluates the mid‐term outcomes of the first in‐human digital nerve reconstruction using the SILKBridge, focusing on sensory recovery, complication rates, patient‐reported outcomes, and biological integration.This study included four patients with digital nerve defects reconstructed using the SILKBridge. Clinical assessments included two‐point discrimination, Semmes–Weinstein monofilament testing, and pain evaluation using the Numeric Rating Scale. Sonographic assessments were also performed to evaluate the conduit's biointegration and potential complications.At a mean follow‐up of 32 months, all patients demonstrated satisfactory sensory recovery and reported minimal to no pain. Sonographic assessments confirmed effective biointegration with no signs of inflammation or scarring.The mid‐term evaluation of the first in‐human digital nerve reconstruction with the SILKBridge revealed safety, efficiency, and favorable biocompatibility properties. Further studies with larger cohorts are needed to validate these findings and compare them with other nerve repair methods. [ABSTRACT FROM AUTHOR]

Background: Optimal functional recovery following peripheral nerve injuries (PNIs) is dependent upon early recognition and prompt referral to specialist centres for appropriate surgical intervention. Technologies which facilitate the early detection of PNI would allow faster referral rates and encourage improvements in patient outcomes. Serum Neurofilament light chain (NfL) measurements are cheaper to perform, easier to access and interpret than many conventional methods used for nerve injury diagnosis, such as electromyography and/or magnetic resonance imaging assessments, but changes in serum NfL levels following traumatic PNI have not been investigated. This pre‐clinical study aimed to determine whether serum NfL levels can: (1) detect the presence of a nerve trauma and (2) delineate between different severities of nerve trauma. Methods: A rat sciatic nerve crush and common peroneal nerve crush were implemented as controlled animal models of nerve injury. At 1‐, 3‐, 7‐ and 21‐days post‐injury, serum samples were retrieved for analysis using the SIMOA® NfL analyser kit. Nerve samples were also retrieved for histological analysis. Static sciatic index (SSI) was measured at regular time intervals following injury. Results: Significant 45‐fold and 20‐fold increases in NfL serum levels were seen 1‐day post‐injury following sciatic and common peroneal nerve injury, respectively. This corresponded with an eightfold higher volume of axons injured in the sciatic compared to the common peroneal nerve (p <.001). SSI measurements post‐injury revealed greater reduction in function in the sciatic crush group compared with the common peroneal crush group. Conclusions: NfL serum measurements represent a promising method for detecting traumatic PNI and stratifying their severity. Clinical translation of these findings could provide a powerful tool to improve the surgical management of nerve‐injured patients. [ABSTRACT FROM AUTHOR]

The objectives of this study were (1) epidemiological analysis of traumatic peripheral nerve injuries; (2) assessment of neuropathic pain and quality of life in patients affected by traumatic neuropathies. All consecutive patients with a diagnosis of traumatic neuropathies from four Italian centres were enrolled. Electromyography confirmed clinical level and site diagnosis of peripheral nerve injury. All patients were evaluated by disability scales, pain screening tools, and quality of life tests. 158 consecutive patients for a total of 211 traumatic neuropathies were analysed. The brachial plexus was a frequent site of traumatic injury (36%) and the radial, ulnar, and peroneal were the most commonly involved nerves with 15% of iatrogenic injuries. Seventy-two percent of the traumatic neuropathies were painful. Pain was present in 66% and neuropathic pain in 50% of all patients. Patients had worse quality of life scores than did the healthy Italian population. Moreover, there was a strong correlation between the quality of life and the severity of the pain, particularly neuropathic pain (Short Form-36 [SF-36] p < 0.005; Beck Depression Inventory [BDI] p < 0.0001). Traumatic neuropathies were more frequent in young males after road accidents, mainly in the upper limbs. Severe neuropathic pain and not only disability contributed to worsening the quality of life in patients with traumatic neuropathies. [ABSTRACT FROM AUTHOR]

A correction to the article "Serum neurofilament light chain measurements following nerve trauma" in the J Peripher Nerv Syst. (2023;28(3):500–507) issue is presented which discusses an error in the serum neurofilament light chain data analysis.

Cold intolerance and pain can be a substantial problem in patients with peripheral nerve injury. We aimed at investigating the relationships among sensory recovery, cold intolerance, and neuropathic pain in patients affected by upper limb peripheral nerve injury (Sunderland type V) treated with microsurgical repair, followed by early sensory re‐education. In a cross‐sectional clinical study, 100 patients (male/female 81/19; age 40.5 ± 14.8 years and follow‐up 17 ± 5 months, mean ± SD), with microsurgical nerve repair and reconstruction in the upper extremity and subsequent early sensory re‐education, were evaluated, using Cold Intolerance Symptoms Severity questionnaire‐Italian version (CISS‐it, cut‐off pathology >30/100 points), CISS questionnaire‐12 item version (CISS‐12, 0‐46 points‐grouping: healthy that means no cold intolerance [0‐14], mild [15‐24], moderate [25‐34], severe [35‐42], very severe [43‐46] cold intolerance), probability of neuropathic pain (DouleurNeuropathique‐4; [DN4] 4/10), deep and superficial sensibility, tactile threshold (monofilaments), and two‐point discrimination (cutoff S2; Medical Research Council scale for sensory function; [MRC‐scale]). A high CISS score is associated with possible neuropathic pain (DN4 ≥ 4). Both a low CISS‐it score (ie, < 30) and DN4 < 4 is associated with good sensory recovery (MRC ≥ 2). In conclusion patients affected by upper limb peripheral nerve injuries with higher CISS scores more often suffer from cold intolerance and neuropathic pain, and the better their sensory recovery is, the less likely they are to suffer from cold intolerance and neuropathic pain. [ABSTRACT FROM AUTHOR]

Initially identified in Drosophila, the Hippo signaling pathway regulates how cells respond to their environment by controlling proliferation, migration and differentiation. Many recent studies have focused on characterizing Hippo pathway function and regulation in mammalian cells. Here, we present a brief overview of the major components of the Hippo pathway, as well as their regulation and function. We comprehensively review the studies that have contributed to our understanding of the Hippo pathway in the function of the peripheral nervous system and in peripheral nerve diseases. Finally, we discuss innovative approaches that aim to modulate Hippo pathway components in diseases of the peripheral nervous system. [ABSTRACT FROM AUTHOR]

Despite the peripheral nervous systems (PNS) capacity to regenerate, functional restoration is highly variable following peripheral nerve injury (PNI), oftentimes leading to persistent functional deficits. In the preclinical arena, advances in the therapeutic use of exogenous neurotrophic factors and synthetic neural scaffold technology hold promise in augmenting endogenous PNS regeneration following PNI. Clinical trials utilizing neurotrophic factors for other indications (eg, peripheral neuropathy) may provide insight into their role in PNI. Here we provide an updated review of progress made toward enhancing regeneration after PNI with a focus on neurotrophic factors and bioengineered scaffolds. [ABSTRACT FROM AUTHOR]

Peripheral nerve injuries caused by focal constriction are characterised by local nerve ischaemia, axonal degeneration, demyelination, and neuroinflammation. The aim of this study was to understand temporal changes in the excitability properties of injured motor axons in a mouse model of nerve constriction injury (NCI). The excitability of motor axons following unilateral sciatic NCI was studied in male C57BL/6J mice distal to the site of injury at the acute (6 hours‐1 week) and chronic (up to 20 weeks) phases of injury, using threshold tracking. Multiple measures of nerve excitability, including strength‐duration properties, threshold electrotonus, current‐threshold relationship, and recovery cycle were examined using the automated nerve excitability protocol (TRONDNF). Acutely, injured motor axons developed a pattern of excitability characteristic of ischemic depolarisation. In most cases, the sciatic nerve became transiently inexcitable. When a liminal compound muscle action potential could again be recorded, it had an increase in threshold and latency, compared to both pre‐injury baseline and sham‐injured groups. These axons showed a greater threshold change in response to hyperpolarising threshold electrotonus and a significant upward shift in the recovery cycle. Mathematical modelling suggested that the changes seen in chronically injured axons involve shortened internodes, reduced myelination, and exposed juxtaparanodal fast K+ conductances. The findings of this study demonstrate long‐term changes in motor excitability following NCI (involving alterations in axonal properties and ion channel activity) and are important for understanding the mechanisms of neurapraxic injuries and traumatic mononeuropathies. [ABSTRACT FROM AUTHOR]

The changes in the expression of brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4) in the rat neuromuscular system as a result of three different types of sciatic nerve injuries have been evaluated. The changes in mRNA and protein levels for BDNF, NT-3, and NT-4 in the soleus muscle and sciatic nerve were assessed 4–28 days after sciatic nerve transection (neurotmesis), sciatic nerve crush (axonotmesis), and mild acute compression (neurapraxia). BDNF mRNA levels increased dramatically with nerve transection in the soleus muscle and the sciatic nerve 7–14 days after injury, whereas the changes were low in other types of injury. The changes of protein levels for BDNF were also similar. The mRNA and the protein levels of NT-3 in the soleus muscle did not show any significant difference. The mRNA for NT-4 in the soleus muscle decreased from 4 to 14 days after sciatic nerve transection, and the protein level was also minimum 14 days after sciatic nerve transection. Our results indicate that the neurotrophic factors in the neuromuscular system could play a role in differentiating peripheral nerve injury. [ABSTRACT FROM AUTHOR]

The capacity of Schwann cells (SCs) in the peripheral nervous system to support axonal regeneration, in contrast to the oligodendrocytes in the central nervous system, has led to the misconception that peripheral nerve regeneration always restores function. Here, we consider how prolonged periods of time that injured neurons remain without targets during axonal regeneration (chronic axotomy) and that SCs in the distal nerve stumps remain chronically denervated (chronic denervation) progressively reduce the number of motoneurons that regenerate their axons. We demonstrate the effectiveness of low-dose, brain-derived neurotrophic and glial-derived neurotrophic factors to counteract the effects of chronic axotomy in promoting axonal regeneration. High-dose brain-derived neurotrophic factor (BDNF) on the other hand, acting through the p75 receptor, inhibits axonal regeneration and may be a factor in stopping regenerating axons from forming neuromuscular connections in skeletal muscle. The immunophilin, FK506, is also effective in promoting axonal regeneration after chronic axotomy. Chronic denervation of SCs (>1 month) severely deters axonal regeneration, although the few motor axons that do regenerate to reinnervate muscles become myelinated and form enlarged motor units in the reinnervated muscles. We found that in vitro incubation of chronically denervated SCs with transforming growth factor-β re-established their growth-supportive phenotype in vivo, consistent with the idea that the interaction between invading macrophages and denervated SCs during Wallerian degeneration is essential to sustain axonal regeneration by promoting the growth-supportive SC phenotype. Finally, we consider the effectiveness of a brief period of 20 Hz electrical stimulation in promoting the regeneration of axons across the surgical gap after nerve repair. [ABSTRACT FROM AUTHOR]

The majority of human peripheral nerve injuries occur in the upper limb but the majority of studies in the rat are performed in the hindlimb. The upper and lower limbs differ in dexterity and control by supraspinal systems, so an upper limb model is a better representation of the common form of human injury. The purpose of this study was to further develop a rat model involving lesions of the median and ulnar nerves. To produce different degrees of misdirection of axons following nerve repair, we studied nerve crush, cut and repair of the two nerves, and cut and repair with crossover. Assessment of functional recovery was performed using a battery of motor and sensory tests: the staircase test, which assesses skilled forepaw reaching; grip strength meter, which assesses grip strength; pawprint analysis, which assesses toe spread and print length; horizontal ladder, which assesses forepaw placement during skilled locomotion; modified Randall-Selitto device and electronic von Frey probes, which assess fine touch; and cold probes, which assess temperature sensation. All tests revealed deficits in forepaw function after nerve injury except the print length and modified Randall-Selitto device. The time course of functional recovery was observed over 15 weeks. The final degree of functional recovery achieved was related to the misdirection of axon regeneration. The tests that most clearly revealed the effects of axon misdirection on function were the skilled paw reaching and grip strength tests. The lesion model and functional tests that we have developed will be useful in testing therapeutic strategies for treating the consequences of inaccurate axon regeneration following peripheral nerve injury in humans. [ABSTRACT FROM AUTHOR]

Transgenic mice have been previously used to assess nerve regeneration following peripheral nerve injury. However, mouse models are limited by their small caliber nerves, short nerve lengths, and their inability to fully participate during behavioral assessments. The transgenic Thy1 GFP rat is a novel transgenic rat model designed to assess regeneration following peripheral nerve injury. However, return of functional and behavioral recovery following nerve injury has not yet been evaluated in these rats. In this study, we ask whether differences in anatomy, recovery of locomotion, myological, and histomorphological measures exist between transgenic Thy1 GFP rats when compared to wild type ( WT) Sprague Dawley rats following unilateral sciatic nerve injury. We found that both motor and sensory neuronal architecture, overground and skilled locomotion, muscle force, motor unit number estimation ( MUNE) and wet muscle weights, and histomorphometric assessments are similar between both genetic phenotypes. Overall, these data support the use of the transgenic Thy1- GFP rat in experiments assessing functional and behavioral recovery following nerve injury and repair. [ABSTRACT FROM AUTHOR]

Peripheral nerve injury triggers the activation of the small GTPase RhoA in spinal motor and peripheral sensory neurons. C3 transferase, an exoenzyme produced by Clostridium botulinum that inactivates RhoA by ADP-ribosylation, has been successfully applied in central nervous system ( CNS) lesion models to facilitate regeneration functionally and morphologically. Until now it has not been demonstrated if C3bot exerts positive effects on peripheral axon regeneration as well. In organotypic spinal cord preparations, C3bot reduced axonal growth of motoneurons, while no effect on sensory axon outgrowth from dorsal root ganglia ( DRG) explants was observed. Enzymatically inactive C3E174Q was ineffective in both culture models. Spinal cord slices exhibited a significant increase in microglia/macrophages after treatment with C3bot suggesting an inflammatory component in the inhibition of axon growth. C3bot or C3E174Q were then applied into conduits implanted after transection of the sciatic nerve in rats. Functional evaluation by electrophysiology, nociception, and walking track tests did not show any significant difference between groups with active or mutant C3E174Q. Transmission electron microscopy of the regenerated nerves revealed no significant differences in the number of myelinated and unmyelinated axons 6 weeks after surgery. Compared to the CNS, the functional significance of RhoA may be limited during nerve regeneration in a growth-promoting environment. [ABSTRACT FROM AUTHOR]

During 3 years, my research activities in Jack Griffin's laboratory focused on the influence of β-amyloid precursor protein cleaving enzyme 1 ( BACE1) on the degeneration/regeneration of sciatic nerve of mice. Here, potential mechanisms of how BACE1 enzymatic activity influences these processes are discussed. [ABSTRACT FROM AUTHOR]

This review provides an overview of selected aspects of peripheral nerve regeneration and potential avenues to explore therapeutically. The overall coordinated and orchestrated pattern of recovery from peripheral nerve injury has a beauty of execution and progress that rivals all other forms of neurobiology. It involves changes at the level of the perikaryon, coordination with important peripheral glial partners, the Schwann cells, a controlled inflammatory response, and growth that overcomes surprising intrinsic roadblocks. Both regenerative axon growth and collateral sprouting encompass fascinating aspects of this story. Better understanding of peripheral nerve regeneration may also lead to enhanced central nervous system recovery. [ABSTRACT FROM AUTHOR]

Current treatments of injured peripheral nerves often fail to mediate satisfactory functional recovery. For axonal regeneration, neurotrophic factors (NTFs) play a crucial role. Multiple NTFs and other growth-promoting factors are secreted, amongst others, by Schwann cells (SCs), which also provide cellular guidance for regenerating axons. Therefore, delivery of NTFs and transplantation of autologous or genetically modified SCs with therapeutic protein expression have been proposed. This article reviews polymer-based and cellular approaches for NTF delivery, with a focus on SCs and strategies to modulate SC gene expression. Polymer-based NTF delivery has mostly resided on nerve conduits (NC). While NC have generally provided prolonged NTF release, their therapeutic effect has remained significantly below that achieved with autologous nerve grafts. Several studies demonstrated enhanced nerve regeneration using NC seeded with SCs. The SCs have sometimes been modified genetically using non-viral or viral vectors. Whereas non-viral vectors produced poor transgene delivery, adenoviral vectors mediated high transgene transduction efficiency of SCs. Further improvements of safety and transgene expression of adenoviral vector may lead to rapid translation of pre-clinical research to clinical trials. [ABSTRACT FROM AUTHOR]

Neuropathic pain that develops after trauma to a nerve may be caused by altered transcription of genes in the damaged neurons. We have previously investigated the effect of nerve injury on the expression of six dorsal root ganglion (DRG) pain candidate molecules in five inbred mouse strains with different pain phenotypes after nerve injury. In this study, we present a detailed morphological examination of mRNA expression in the DRG in the same mouse strains. For Nav 1.9, TRPA1, and TRPM8, the size spectra of labeled neurons remained mostly unchanged after injury in all strains. However, in CBA, AKR, and C58 mice, injury caused a preferential downregulation of Nav 1.8 in large diameter neurons. In CBA mice there was a shift toward larger neuronal profiles expressing TRPV1 after injury, indicating de novo (or upregulated) expression of TRPV1 in a subpopulation of neurons that normally does not express this gene. Finally, in C58 mice there was a shift toward smaller P2X3-expressing neuronal profiles after injury, suggesting that a loss of P2X3 mRNA transcript occurred preferentially in medium-sized cells. We used a multivariate statistical model to compare the regulation patterns of the six DRG genes. Clustering patterns suggested that genes of similar phylogenetic origin and function are regulated similarly. [ABSTRACT FROM AUTHOR]

In developing countries, injections are frequently used to treat common ailments. Intramuscular injections (IMI) may damage peripheral nerves at the site of injection. Our objectives were to study the clinical features, neurophysiological findings, and outcome in patients with nerve injuries (NI) following IMI and to determine the factors affecting prognosis. We conducted a retrospective review of patients with NI following IMI, who were referred to our Neurophysiology Laboratory at Christian Medical College, Ludhiana, India, between January 1990 to December 2003. There were 36 (55%) patients with sciatic nerve palsy, 29 (44%) patients with radial nerve injury, and 1 (1%) patient with posterior femoral cutaneous nerve injury. In 57 (86%) patients, the IMI were given by uncertified medical practitioners. Needle electromyography (EMG) was analyzed in 36 patients (≥60 days after onset). In 12 (33%) patients, there was EMG evidence of axonal damage with reinnervation, while in the other 24 (67%) patients, there was axonal damage without reinnervation. Only 18 (28%) patients had a good recovery. In conclusion, NI following IMI is a preventable iatrogenic hazard, which carries a poor prognosis. [ABSTRACT FROM AUTHOR]

Some of the sensory abnormalities that follow peripheral nerve injury may result from the development of ectopic discharge from the damaged axons. Previous studies in our laboratory have shown that, following tight ligation of the inferior alveolar nerve (IAN), there is a close association between the time-course of this neural activity and the accumulation of neuropeptides at the injury site. In this study we investigated whether the type of injury has any effect on the time-course or level of neuropeptide expression. In 36 adult ferrets, the IAN was either loosely constricted or sectioned, and the animals left to recover for 3 days, 3 weeks, or 3 months. The tissue was processed using indirect immunofluorescence and image analysis was used to quantify levels of substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, enkephalin, galanin, and neuropeptide Y. Immunoreactivity to all of the neuropeptides was present within the injured nerve 3 days after both types of injury, and decreased to lower levels by 3 weeks and 3 months. Comparisons between the levels of neuropeptide immunoreactivity in each group revealed that the pattern of accumulation was similar following loose constriction or section, and also similar to that found in our previous study on tight ligation. For each injury the time-course of neuropeptide expression was similar to that of the spontaneous activity we had previously recorded. These data support the suggestion that neuropeptide accumulation may be linked to the development of ectopic neural activity but indicate that the type of injury has little effect on the extent of expression. [ABSTRACT FROM AUTHOR]

Regeneration of diabetic axons has delays in onset, rate and maturation. It is possible that microangiopathy of vasa nervorum, the vascular supply of the peripheral nerve, may render an unfavorable local environment for nerve regeneration. We examined local nerve blood flow proximal and distal to sciatic nerve transection in rats with long-term (8 month) experimental streptozotocin diabetes using laser Doppler flowmetry and microelectrode hydrogen clearance polarography. We then correlated these findings, using in vivo perfusion of an India ink preparation, by outlining the lumens of microvessels from unfixed nerve sections. There were no differences in baseline nerve blood flow between diabetic and nondiabetic uninjured nerves, and vessel number, density, and area were unaltered. After transection, there were greater rises in blood flow in proximal stumps of nondiabetic nerves than in diabetic animals associated with a higher number, density, and caliber of epineurial vessels. Hyperemia also developed in distal stumps of nondiabetic nerves but did not develop in diabetic nerves. In these stumps, diabetic rats had reduced vessel numbers and smaller mean endoneurial vessel areas. Failed or delayed upregulation of nerve blood flow after peripheral nerve injury in diabetes may create a relatively ischemic regenerative microenvironment. [ABSTRACT FROM AUTHOR]

It was argued that researchers and clinicians are not able to make judgments between most categories of the original Medical Research Council (MRC) scale and that a modified short version would reach higher agreement levels. We aimed to assess the inter‐rater reliability for both the original and the Rasch‐modified MRC scoring criteria of Manual Muscle Strength tests (MMSt) in patients with neuromuscular diseases. Two MRC scoring criteria were used to score muscle strength using MMSt in 40 muscle groups of the upper and lower limbs in patients with neuromuscular disorders. Three investigators performed the evaluations; the order of the MMSt and the use of the scales were performed according to the preferences of the investigators. The agreement coefficient (Gwet's AC2) was used to compute the reliability. Sixty patients (mean age of 39.3 years ± 15.2) with neuromuscular diseases were included. The mean AC2 for the muscle groups of the upper limbs ranged from 0.82 to 0.96 using the modified MRC scale and from 0.86 to 0.96 using the original MRC scale. The AC2 for the lower limb muscle groups ranged from 0.80 to 0.91 (modified MRC scale) and from 0.87 to 0.93 (original MRC scale). These values might be interpreted as "almost perfect agreement" with no significant differences between the scales. The results indicate that both MRC scoring criteria have significant reliability among trained observers. Moreover, the Rasch‐modified MRC scale is as reliable as the original MRC scale and can be used in future clinical studies. [ABSTRACT FROM AUTHOR]

The article focuses on 33rd annual meeting of the publisher featuring educational seminar related to tissue engineering, symposium on peripheral nerve regeneration, and luncheon seminar on autoimmune nodopathies.

The article presents multiple medical researches. Researches include Ckd-510, a novel non-hydroxamic acid histone Deacetylase 6 (hdac6) inhibitor for charcot-marietooth Disease type 1a, Evaluating the causes of rapid-progressive Sensorimotor polyneuropathy in a patient with Cadasil and plasmacytoma-associated Paraproteinemia, and Low intensity pulsed ultrasound modulates axonal Regrowth and remyelination after peripheral nerve Injury.

Increasing literature has linked COVID‐19 to peripheral nervous system (PNS) diseases. In addition, as we move from the pandemic to the vaccination era, literature interest is shifting towards the potential association between COVID‐19 vaccines and PNS manifestations. We reviewed published literature on COVID‐19, COVID‐19 vaccines and PNS manifestations between 1 January 2020 and 1 December 2021. For Guillain‐Barré syndrome (GBS), isolated cranial neuropathy (ICN) and myositis associated with COVID‐19, the demographic, clinical, laboratory, electrophysiological and imaging features were included in a narrative synthesis. We identified 169 studies on COVID‐19‐associated complications, including 63 papers (92 patients) on GBS, 29 papers (37 patients) on ICN and 11 papers (18 patients) on myositis. Additional clinical phenotypes included chronic inflammatory demyelinating polyneuropathy, vasculitic neuropathies, neuralgic amyotrophy, critical care‐related complications, and myasthenia gravis. PNS complications secondary to COVID‐19 vaccines have been reported during randomized clinical trials, in real‐world case reports, and during large‐scale surveillance programs. These mainly include cases of GBS, Bell's palsy, and cases of neuralgic amyotrophy. Based on our extensive review of the literature, any conclusion about a pathophysiological correlation between COVID‐19 and PNS disorders remains premature, and solely supported by their temporal association, while epidemiological and pathological data are insufficient. The occurrence of PNS complications after COVID‐19 vaccines seems limited to a possible higher risk of facial nerve palsy and GBS, to a degree that widespread access to the ongoing vaccination campaign should not be discouraged, while awaiting for more definitive data from large‐scale surveillance studies. [ABSTRACT FROM AUTHOR]

Despite its widespread use, little is known regarding the ability of the semi‐quantitative Rydel‐Seiffer tuning fork to designate peripheral nerve function. We sought to determine in a large sample of normal and abnormal nerves the relationship between vibration sense and compound sensory nerve action potential (SNAP) parameters recorded in a corresponding innervation area. Vibratory thresholds were determined on a scale of 0 to 8 with a 64 Hz Rydel‐Seiffer tuning fork placed on the lateral malleolus of 303 subjects. Sural nerve sensory neurography was employed to derive SNAP parameters, which were related to vibration sense by means of multiple linear regression. ROC curve analysis was performed to determine the classification efficacy of the tuning fork in distinguishing normal from abnormal sural nerve responses. SNAP amplitude was the most significant predictor in the whole subjects group and in the subgroup of subjects with normal SNAPs, whereas conduction velocity played a major role in subjects with abnormal SNAPs. Age was significantly associated with vibration perception, particularly in subjects with normal SNAPs. With an area under the curve of 0.730, vibration sense was a fair classifier for decreased SNAP amplitudes. The optimal vibratory cutoff was 4.2. Age is a major determinant of vibratory test results, highlighting the importance of aging of central and peripheral pathways in mediating vibration sense. Hence, neurophysiological testing cannot be omitted in the context of polyneuropathy work‐up, since even at the optimal cutoff threshold, vibratory examination still displays 40% false negative test results. [ABSTRACT FROM AUTHOR]

The gold standard for peripheral nerve regeneration uses a sensory autograft to bridge a motor/sensory defect site. For motor nerves to regenerate, Schwann cells (SC) myelinate the newly grown axon. Sensory SCs have a reduced ability to produce myelin, partially explaining low success rates of autografts. This issue is masked in pre‐clinical research by the excessive use of the rat sciatic nerve defect model, utilizing a mixed nerve with motor and sensory SCs. Aim of this study was to utilize extracorporeal shockwave treatment as a novel tool to influence SC phenotype. SCs were isolated from motor, sensory and mixed rat nerves and in vitro differences between them were assessed concerning initial cell number, proliferation rate, neurite outgrowth as well as ability to express myelin. We verified the inferior capacity of sensory SCs to promote neurite outgrowth and express myelin‐associated proteins. Motor Schwann cells demonstrated low proliferation rates, but strongly reacted to pro‐myelination stimuli. It is noteworthy for pre‐clinical research that sciatic SCs are a strongly mixed culture, not representing one or the other. Extracorporeal shockwave treatment (ESWT), induced in motor SCs an increased proliferation profile, while sensory SCs gained the ability to promote neurite outgrowth and express myelin‐associated markers. We demonstrate a strong phenotype commitment of sciatic, motor, and sensory SCs in vitro, proposing the experimental use of SCs from pure cultures to better mimic clinical situations. Furthermore we provide arguments for using ESWT on autografts to improve the regenerative capacity of sensory SCs. [ABSTRACT FROM AUTHOR]

Depletion of myelin and neurobehavioural deficits are indications that vanadium crosses the blood‐brain barrier and such neurotoxic effects of vanadium on the brain of Wistar rats have been elucidated. The effect however on the peripheral nerves, is yet to be reported. Thus, this work was designed to evaluate the axonal and myelin integrity of sciatic nerves in Wistar rats following exposure to vanadium. Ten male Wistar rats were exposed to 3 mg/kg body weight of sodium metavanadate for 7 days, subjected to rearing and forelimb grip behavioural tests, and sciatic nerves processed for histology (haematoxylin and eosin, cresyl violet, and luxol fast blue). Dystrophic axons with vesiculated myelin, thinned myelin sheath, and demyelinated axons were observed in the vanadium exposed rats, suggestive of axonopathy, classified as fourth‐degree nerve injury. Lower behavioural scores were recorded for vanadium‐dosed rats; thus, corroborating histological pictures observed of the sciatic nerves. Authors posit that vanadium crossed the "blood‐nerve" barrier and caused the observed axonal pathologies and myelin depletion in the sciatic nerves of these rodents with resultant motor deficits. The present paper discusses possible motor deficits and the likely public health importance in regions with crude oil pollution and gas flaring rich in vanadium products. [ABSTRACT FROM AUTHOR]

The article offers information on 2018 Peripheral Nerve Society Annual Meeting from 21-25 July, 2018 at Baltimore, Maryland. It mentions several topics discussed in meeting that includes role of Microangiopathy in the pathogenesis of diabetic neuropathy; validity and diagnostic capability of patient and clinician reported measures of chemotherapy induced peripheral neuropathy (CIPN); and role of Sirt2 in alleviating cisplatin induced peripheral neuropathy pain.

The article offers information on the 2017 Peripheral Nerve Society Meeting to be held at Barcelona, Spain from July 8–12, 2017, the 2018 meeting at Renaissance Baltimore Harborplace Hotel in Baltimore, Maryland from July 22–25, 2018 and members of the society.

The article presents abstracts on topics related to peripheral nervous system including the inherited neuropathy consortium, the regulation of transient receptor potential vanilloid 4 and the rare disease' inherited neuropathies consortium.

The article presents several abstracts to be presented at the 2015 Peripheral Nerve Society Biennial Meeting from June 27-July 2, 2015 in Québec City, Québec, Canada, including medicine for Guillain-Barré syndrome (GBS), Charcot-Marie-Tooth (CMT) disease and cell mechanism in neuropathic pain.

The scores used to evaluate sensibility after digital nerve reconstruction do not take the patient's age into consideration, although there is evidence that the outcome after digital nerve reconstruction is age-dependent. However, it is not clear if the normal sensibility of the hand is also age-dependent, as the existing studies have major limitations. We evaluated the normal sensibility of the hand in 232 patients using static and moving two-point discrimination ( 2PD) tests and the Semmes-Weinstein-monofilament test. We found the climax of sensibility in the third decade with age-dependent deterioration afterwards in all three tests. Mean 2PD values of the radial digital nerve of the index finger ( N3) showed to be significantly lower than values of the ulnar digital nerve of the small finger ( N10). To overcome shortcomings of classification systems that do not consider the patient's age and inter-individual differences, we suggest using the difference of the static 2PD values of the injured to the uninjured contralateral nerve (delta 2PD) for assessment of sensibility after digital nerve reconstruction. [ABSTRACT FROM AUTHOR]

Thirty percent of Guillain-Barré syndrome ( GBS) patients require mechanical ventilation (MV) in intensive care unit ( ICU). Post-traumatic stress disorder ( PTSD) is found in ICU survivors, and the traumatic aspects of intubation and MV have been previously reported as risk factors for PTSD after ICU. Our objective was to determine long-term PTSD or post-traumatic stress symptoms (PTSS) in GBS patients after prolonged MV in ICU. We assessed GBS patients who had MV for more than 2 months. PTSD was assessed using Horowitz Impact of Event Scale ( IES), IES-Revisited ( IES-R), and the Post-traumatic CheckList Scale; functional outcome using Rankin and Barthel scales; quality of life ( QoL) using Nottingham Health Profile ( NHP) and 36-Item Short Form Health Survey ( SF-36) and depression using Hospital Anxiety and Depression Scale ( HAD) and Beck questionnaire. Thirteen patients could be identified and analyzed. They had only mild disability. They were neither anxious nor depressed with an anxiety HAD at 5 (4-11.5), a depression HAD at 1 (0-3.5) and a Beck at 1 (0-5). QoL was mildly decreased in our population with a NHP at 78.5 (12.8-178.8) and mild decreased SF-36. Compared with the French population, the SF-36 sub-categories were, however, not statistically different. Twenty-two percentage of our 13 patients had PTSD and PTSS with a Horowitz IES at 12 (2-29), and an IES-R at 16 (2-34.5). Although severe GBS patients requiring prolonged MV had good functional recovery and no difference in QoL, they had a high incidence of PTSS. [ABSTRACT FROM AUTHOR]

The inability to compare directly different nerve grafts has been a significant factor hindering the advance of nerve graft development. Due to the abundance of variables that exist in nerve graft construction and multiple assessment types, there has been limited success in comparing nerve graft effectiveness among experiments. Using mathematical techniques on nerve conduction velocity ( NCV) autograft data, a normalization function was empirically derived that normalizes differences in gap lengths. Further analysis allowed for the development of the relative regeneration ratio ( RRR). The RRR function allows researchers to directly compare nerve graft results based on the NCV data from their respective studies as long as the data was collected at the same post-operation time. This function also allows for comparisons between grafts tested at different gap lengths. Initial testing of this RRR function provided confidence that the function is accurate for a continuum of gap lengths and different nerve graft types. [ABSTRACT FROM AUTHOR]

The article gives information about the 2013 meeting of the Peripheral Nerve Society which will be held in Saint-Malo, France on June 29-July 3, 2013 and notes abstracts of research presentations on topics such as Charcot-Marie-Tooth disease, diabetic nephropathies, and immunosuppressive-induced neuropathies.

This is a brief review of several novel strategies for therapeutic approaches to axonal damage in peripheral neuropathies. Although not comprehensive, the review addresses the challenges in axonal regrowth, newly identified roadblocks to regeneration and the concept of collateral reinnervation to restore lost neurological function. [ABSTRACT FROM AUTHOR]

End-to-side (ETS) neurorrhaphy is an option in peripheral nerve surgery. The aim of this study was to investigate whether the application of the anti-inflammatory cytokine interleukin-10 (IL-10) reduces scarring and thus enhances nerve regeneration in an ETS peroneal/tibial nerve lesion model of the rat. Twenty rats with a peroneal to tibial ETS neurorrhaphy were divided into two groups: (1) control group and (2) IL-10 group with intrafascicular application of 0.125 µg/100 µl IL-10. Survival time was 8 weeks. Nerve conduction velocities (NCVs) and motor function were analyzed and histomorphological evaluation with measurement of intraneural collagen level, axon count, total nerve area, and myelination index followed. Evaluation of motor function and nerve conduction did not show any statistical differences. Histological analyses revealed thicker myelin sheaths and higher myelination index in the IL-10 group (p < 0.001). Axon count showed no difference. The IL-10 group revealed lower collagen levels (p < 0.001). Comparison of total nerve area showed no statistical significance. At this dose, IL-10 evaluated at 8 weeks was not significantly different than placebo in functional, NCVs, and most morphological measures. However, there was a significant difference in thicker myelin sheaths and higher myelination index and lower collagen levels. This suggests that future experiments of IL-10 at different doses or longer periods of evaluation would be of interest. [ABSTRACT FROM AUTHOR]

The article presents several abstracts presented at the 2011 meeting of the Peripheral Nerve Society, which was held on June 25-29 in Potomac, Maryland including one on dorsal root ganglion neuronal degeneration in HIV/AIDS, one on neuropathies in amyloid polyneuropathy and one on hereditary neuropathies in a Malaysian population.

There is a scarcity of validated hand performance tests with proven reliability for quantifying functional deficits in patients with carpal tunnel syndrome (CTS). The Dellon-modified Moberg pick-up test (DMMPUT), composed of commonly used daily objects, is potentially well suited for that purpose. This study was designed to evaluate the test-retest reliability and discriminative validity of the DMMPUT in CTS patients. We compared 162 CTS patients with 116 age-matched controls. CTS severity was determined based on electrophysiological parameters and Levine's Self-Assessment Questionnaire. The mean time to complete each subset of the DMMPUT by the CTS patients was compared with that by the healthy subjects. Test-retest reliability was examined in 46 CTS patients. Discriminative validity was demonstrated through a significant difference in test completion time between the CTS subjects and their age-matched controls. With few exceptions, the test scores declined with increasing severity of electrophysiological abnormalities and subjective symptom severity. Test-retest reliability of the DMMPUT was high with an intra-class correlation coefficient of 0.91. The DMMPUT has discriminative validity and high test-retest reliability in patients with CTS. It can be a useful standardized outcome measure to gauge disease severity. [ABSTRACT FROM AUTHOR]

A number of receptor tyrosine kinases (RTKs) and the downstream phosphatidylinositol-3-kinase (PI3K)/Akt and mitogen-activated protein (MAP) kinase signaling pathways have been critically involved in peripheral nerve regeneration. Here, we examined the activation of PI3K/Akt and MAP kinase pathways, and platelet-derived growth factor receptors (PDGFRs) in the distal segments of crushed rat sciatic nerve from 3 to 28 days after injury. In Western blot analyses, the phosphorylated forms of extracellular signal-regulated protein kinase (ERK) and c-Jun NH2-terminal kinases (JNKs) were highly augmented on days 3 and 7 and on days 7 and 14 after injury, respectively. Phosphorylated Akt and p38 consistently increased from 3 to 28 days after injury. Phosphorylated PDGFR-α and -β were also increased from 3 to 14 days. In the immunohistological analyses, phosphorylated ERK and PDGFR-α were co-localized in many activated Schwann cells and regrowing axons 3 days after injury, while PDGFR-β was localized in a few spindle-shaped cells. The detected temporal profile of RTK signaling appears to be crucial for the regulation of Schwann cell proliferation and following redifferentiation. Furthermore, the immunohistological studies suggested a role of ERK and PDGFR-α in axon regeneration as well. [ABSTRACT FROM AUTHOR]

The stimulation of peripheral nerve regeneration has been studied in different ways, including the use of electrical fields. The capacity of this modality to enhance nerve regeneration is influenced by the parameters used, including current type, frequency, intensity, and means of administration. Transcutaneous electrical nerve stimulation (TENS) is a frequently used form of administering electrical current to the body, but its effects on peripheral nerve regeneration are not known. This study assessed the influence of TENS on sciatic nerve regeneration, using a model of crush lesion in the mouse. Mice were stimulated 30 min a day, 5 days a week, for 5 weeks with both high- (100 Hz) and low- (4 Hz) frequency TENS. Control animals had the sciatic nerve crushed but were not stimulated. Assessment was performed weekly by functional analysis using the Static Sciatic Index for the mouse and at the end of the experiment by light and electron microscopy. The results showed that although there were no differences between the groups regarding the Static Sciatic Index values, TENS led to nerves with morphological signs of impaired regeneration. At light microscopy level, TENS nerves presented more axons with dark axoplasm, signs of edema, and a less organized cytoarchitecture. Electronmicrographs showed fewer and thinner thick myelinated fibers and increased number of Schwann cell nuclei. Myelinated axon diameters and density and diameter of nonmyelinated fibers were not affected by TENS, leading to the conclusion that this regimen of electrical stimulation leads to a delayed regeneration after a crush lesion of the sciatic nerve in the mouse. All these effects were more pronounced on high-frequency TENS nerves. [ABSTRACT FROM AUTHOR]

Touch sensibility testing is a cost-effective, psychophysical measure of peripheral nerve function and impairment. However, there is limited information regarding the natural variability in touch sensibility across different populations and different age groups. We studied 568 healthy Indian volunteers without any clinical evidence of peripheral nerve disease. Touch sensibility was evaluated bilaterally in palms, feet, and heels, using Semmes-Weinstein monofilaments, with target forces ranging from 0.008 to 300 g. No differences were observed between the right and the left limbs. The lowest target force detected ranged from 0.4 to 2 g in the palms and 1.4 to 15 g in the feet. These values showed further increase with age. Women compared with men had higher sensibility in the palms in most age groups. Touch sensibility thresholds recorded in a large group of Indians were higher than that reported in other populations. These findings have clinical implications for the diagnosis of early nerve impairment in the elderly and in disease states drawing attention to geographic variations in touch sensation. [ABSTRACT FROM AUTHOR]

The object of this study was to demonstrate that digital video motion analysis is a quantitative, valid, and reproducible method for evaluation of function in the rat model of forelimb nerve transection and repair. Median, ulnar, and radial nerves were transected and directly repaired in 220 g Sprague-Dawley rats. Normal rats and sham-operated rats served as controls (six rats in each group). Two-dimensional (2D) digital video motion analysis was used to capture the gait cycle and quantify joint movement and changes in toe spread. Recordings were made preoperatively and at 1, 4, 8, 12, and 16 weeks postoperatively. Wrist and metacarpophalangeal (MP) joint extension decreased after radial nerve injury, and wrist and MP joint flexion decreased after combined median and ulnar nerve injury or injury to the median nerve only. Toe spread decreased after combined median and ulnar nerve injury and after radial nerve injury. Median or ulnar nerve injury alone did not lead to a significant change in toe spread. 2D digital video motion analysis can be used to quantify movement of the wrist and the MP joint in rats. It is a valid method to evaluate functional deficit and recovery after nerve injury and repair in the forelimb. [ABSTRACT FROM AUTHOR]

Axonal regeneration at a site of peripheral nerve repair can be impeded by the formation of scar tissue, which creates a mechanical barrier and initiates the development of multiple branched axonal sprouts that form a neuroma. We have investigated the hypothesis that the application of a scar-reducing agent to the nerve repair site would permit better axonal regeneration. In anaesthetised C57 Black-6 mice, the left sciatic nerve was sectioned and immediately re-approximated using four epineurial sutures. In five groups of eight mice, we injected transforming growth factor-β3 (50 or 500 ng), interleukin-10 (IL-10) (125 or 500 ng), or saline into and around the repair site, both before and after the nerve section. Another group of eight animals acted as sham-operated controls. After 6 weeks, the outcome was assessed by recording compound action potentials (CAPs), measuring collagen levels using picrosirius red staining, and counting the number of myelinated axons proximal and distal to the repair. CAPs evoked by electrical stimulation distal to the repair were significantly smaller in all repair groups except for the low-dose IL-10 group, where they were not significantly different from that in controls. The area of staining for collagen had significantly increased in all repair groups except for the low-dose IL-10 group, which was not significantly different from that in controls. The myelinated fibre counts were always higher distal to the repair site, but there were no significant differences between groups. We conclude that administration of a low-dose of IL-10 to a site of sciatic nerve repair reduces scar formation and permits better regeneration of the damaged axons. [ABSTRACT FROM AUTHOR]