Human Nerve Research Articles

Epineural methylene blue nerve staining on cadaver hand

Introduction: Limited fasciectomy is the gold-standard treatment in Dupuytren’s surgery. The anatomical position of digital nerves can be altered by Dupuytren’s tissue resulting in a difficult dissection and localization, with a relatively high risk of iatrogenic nerve injury. This risk could be decreased by using intraoperative neural marking to facilitate locating the potentially displaced nerves. We recently demonstrated in an animal model that in vivo nerve staining with methylene blue is a suitable method to mark nerves without damaging them. Objective: We aimed to test the efficacy of our methylene blue nerve staining technique developed in a rat sciatic nerve model on human cadaveric digital nerves. Method: First, we performed epineural staining using 40 μl 1 : 80 diluted methylene blue solution on four human cadaver digital nerves fixed with formalin. In the second experiment, we stained six cadaver digital nerves without previous fixation. To increase the length of the stained segments, we used 200 μl solution on two nerves. Results: The epineural nerve labeling was not successful on formalin-fixed tissues. However, nerves without fixation were successfully stained with methylene blue. Forty μl methylene blue solution marked a 13 mm long segment, while 200 μl stained a 18 mm long segment. Conclusion: The epineural methylene blue nerve staining is limited on formalin-fixed digital nerves due tissue shrink-age. Non-fixed nerves with preserved histological structure can be stained in an 18 mm long segment. Further studies are necessary to determine the technique’s value in hand surgery by testing digital nerves surrounded by Dupuytren’s and scar tissues.

Finite element modeling of effects of tissue property variation on human optic nerve tethering during adduction

Tractional tethering by the optic nerve (ON) on the eye as it rotates towards the midline in adduction is a significant ocular mechanical load and has been suggested as a cause of ON damage induced by repetitive eye movements. We designed an ocular finite element model (FEM) simulating 6° incremental adduction beyond the initial configuration of 26° adduction that is the observed threshold for ON tethering. This FEM permitted sensitivity analysis of ON tethering using observed material property variations in measured hyperelasticity of the anterior, equatorial, posterior, and peripapillary sclera; and the ON and its sheath. The FEM predicted that adduction beyond the initiation of ON tethering concentrates stress and strain on the temporal side of the optic disc and peripapillary sclera, the ON sheath junction with the sclera, and retrolaminar ON neural tissue. However, some unfavorable combinations of tissue properties within the published ranges imposed higher stresses in these regions. With the least favorable combinations of tissue properties, adduction tethering was predicted to stress the ON junction and peripapillary sclera more than extreme conditions of intraocular and intracranial pressure. These simulations support the concept that ON tethering in adduction could induce mechanical stresses that might contribute to ON damage.

Multifaceted understanding of human nerve implants to design optimized electrodes for bioelectronics

Bioelectronic medicine is a promising venue for treatment of disabilities using implantable neural interfaces. Peripheral neurostimulation of residual nerves recently enabled multiple functional benefits in amputees. Despite the preliminary promising impact on patients' life, the over-time stability of implants and the related nerve reactions are unclear. To unveil the mechanisms and inform the design of better nerve-electrode interfaces, we engaged a multifaceted approach, merging functional responses from patients, their histological data, and corresponding computational modelling. Neurostimulation evoked different selective sensation locations and qualities over-time, with respective perceptual thresholds, that showed different degree of time stabilities dependent from the stimulating active sites. The histological analysis after explant showed mild tissue reactions, while electromechanically active sites and substrates remained conserved. Computational models, based on patients' histology, revealed the direct influence of the simulated tissue reaction to change of thresholds and type of perceived sensations. Novel insights of electrode biocompatibility was observed compared to animals and the increase of thresholds could be predicted computationally. This multifaced framework suggest that future intraneural implants should have easier implantation and higher biocompatibility counteracting the sensations changes through AI-based stimulations and electrode coatings.

Quantitative Microstructural Analysis of Cellular and Tissue Remodeling in Human Glaucoma Optic Nerve Head.

PurposeTo measure quantitatively changes in lamina cribrosa (LC) cell and connective tissue structure in human glaucoma eyes.MethodsWe studied 27 glaucoma and 19 age-matched non-glaucoma postmortem eyes. In 25 eyes, LC cross-sections were examined by confocal and multiphoton microscopy to quantify structures identified by anti-glial fibrillary acidic protein (GFAP), phalloidin-labeled F-actin, nuclear 4′,6-diamidino-2-phenylindole (DAPI), and by second harmonic generation imaging of LC beams. Additional light and transmission electron microscopy were performed in 21 eyes to confirm features of LC remodeling, including immunolabeling by anti-SOX9 and anti-collagen IV. All glaucoma eyes had detailed clinical histories of open-angle glaucoma status, and degree of axon loss was quantified in retrolaminar optic nerve cross-sections.ResultsWithin LC pores, the proportionate area of both GFAP and F-actin processes was significantly lower in glaucoma eyes than in controls (P = 0.01). Nuclei were rounder (lower median aspect ratio) in glaucoma specimens (P = 0.02). In models assessing degree of glaucoma damage, F-actin process width was significantly wider in glaucoma eyes with more damage (P = 0.024), average LC beam width decreased with worse glaucoma damage (P = 0.042), and nuclear count per square millimeter rose with worse damage (P = 0.019). The greater cell count in LC pores represented 92.3% astrocytes by SOX9 labeling. The results are consistent with replacement of axons in LC pores by basement membrane labeled by anti-collagen IV and in-migrating astrocytes.ConclusionsAlteration in LC structure in glaucoma involves migration of astrocytes into axonal bundles, change in astrocyte orientation and processes, production of basement membrane material, and thinning of connective tissue beams.

The effects of painless nerve growth factor on human microglia polarization.

Previous studies in the rat suggest that microglial cells represent a potential druggable target for nerve growth factor (NGF) in the brain. The painless human Nerve Growth Factor (hNGFp) is a recombinant mutated form of human nerve growth factor (hNGF) that shows identical neurotrophic and neuroprotective properties of wild-type NGF but displays at least 10-fold lower algogenic activity. From the pharmacological point of view, hNGFp is a biased tropomyosin receptor kinase A (TrkA) agonist and displays a significantly lower affinity for the p75 neurotrophin receptor (p75NTR). This study aimed to evaluate the expression of TrkA and p75NTR NGF receptors in two different human microglia cell lines, and to investigate the effects of hNGFp and wild-type NGF (NGF) on L-arginine metabolism, taken as a marker of microglia polarization. Both NGF receptors are expressed in human microglia cell lines and are effective in transducing signals triggered by NGF and hNGFp. The latter and, to a lesser extent, NGF inhibit cytokine-stimulated inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in these cells. Conversely NGF but not hNGFp stimulates arginase-mediated urea production.

Conspecific Identity Determines Interactive Space Area in Zebrafish Shoal.

Sex ratio of shoals has been shown to influence shoaling behavior in many fishes. This study tests whether the conspecific identity influences shoal performance (shoal area, interactive distances, distance traveled, and thigmotaxis) of zebrafish (Danio rerio) via group tracking. We conducted a two-dimensional analysis of shoals with different sex ratios (male only, female only, male rich, and female rich) of a five-membered shoal. Parameters describing the shoal structure and individual behavior were derived using video tracking and a custom-made program. We found that mixed-sex shoals had significantly lesser shoal area and interactive distance compared to single-sex shoals (approximate difference of 80% for shoal area and 50% for interactive distance). Our findings shed light on complex interactive behaviors of zebrafish in a shoal that are affected by differences in sex ratios of interacting individuals. The outcomes from this study can be used to design better zebrafish shoaling experiments for clinically relevant research like human nerve disorders and social deficits.

Totally Organic Hydrogel-Based Self-Closing Cuff Electrode for Vagus Nerve Stimulation.

An intrinsically soft organic electrode consisting of poly(3,4-ethylenedioxythiophene)-modified polyurethane (PEDOT-PU) is embedded into a bilayer film of polyvinyl alcohol (PVA) hydrogels for developing a self-closing cuff electrode for neuromodulation. The curled form of the PVA hydrogel is prepared by releasing internal stress in the bilayer structure. The inner diameter of the cuff electrode is set to less than 2mm for immobilization to the vagus nerve (VN) of humans and pigs. The stability of the immobilization is examined, while the pressure applied to a nerve bundle is at a harmless level (≈200Pa). Since the electrode is totally organic, MRI measurements can be conducted without image artifacts. The large electric capacitance of the PEDOT-PU (≈27 mF cm-2 ) ensures a safe stimulation of living tissues without Faradaic reactions. The practical performance of the cuff electrode for VN stimulation is demonstrated by observation of bradycardia induction in a pig.

Fascicles split or merge every ∼560 microns within the human cervical vagus nerve

Objective. Vagus nerve stimulation (VNS) is Food and Drug Administration-approved for epilepsy, depression, and obesity, and stroke rehabilitation; however, the morphological anatomy of the vagus nerve targeted by stimulatation is poorly understood. Here, we used microCT to quantify the fascicular structure and neuroanatomy of human cervical vagus nerves (cVNs). Approach. We collected eight mid-cVN specimens from five fixed cadavers (three left nerves, five right nerves). Analysis focused on the ‘surgical window’: 5 cm of length, centered around the VNS implant location. Tissue was stained with osmium tetroxide, embedded in paraffin, and imaged on a microCT scanner. We visualized and quantified the merging and splitting of fascicles, and report a morphometric analysis of fascicles: count, diameter, and area. Main results. In our sample of human cVNs, a fascicle split or merge event was observed every ∼560 µm (17.8 ± 6.1 events cm−1). Mean morphological outcomes included: fascicle count (6.6 ± 2.8 fascicles; range 1–15), fascicle diameter (514 ± 142 µm; range 147–1360 µm), and total cross-sectional fascicular area (1.32 ± 0.41 mm2; range 0.58–2.27 mm). Significance. The high degree of fascicular splitting and merging, along with wide range in key fascicular morphological parameters across humans may help to explain the clinical heterogeneity in patient responses to VNS. These data will enable modeling and experimental efforts to determine the clinical effect size of such variation. These data will also enable efforts to design improved VNS electrodes.

Assessment of dynamic corneal nerve changes using static landmarks by in vivo large-area confocal microscopy-a longitudinal proof-of-concept study.

BackgroundThe purpose of the present proof-of-concept study was to use large-area in vivo confocal laser scanning microscopy (CLSM) mosaics to determine the migration rates of nerve branching points in the human corneal subbasal nerve plexus (SNP).MethodsThree healthy individuals were examined roughly weekly over a total period of six weeks by large-area in vivo confocal microscopy of the central cornea. An in-house developed prototype system for guided eye movement with an acquisition time of 40 s was used to image and generate large-area mosaics of the SNP. Kobayashi-structures and nerve entry points (EPs) were used as fixed structures to enable precise mosaic registration over time. The migration rate of 10 prominent nerve fiber branching points per participant was tracked and quantified over the longitudinal period.ResultsTotal investigation times of 10 minutes maximum per participant were used to generate mosaic images with an average size of 3.61 mm2 (range: 3.18–4.42 mm2). Overall mean branching point migration rates of (46.4±14.3), (48.8±15.5), and (50.9±13.9) µm/week were found for the three participants with no statistically significant difference. Longitudinal analyses of nerve branching point migration over time revealed significant time-dependent changes in migration rate only in participant 3 between the last two measurements [(63.7±12.3) and (43.0±12.5) µm/week, P<0.01]. Considering individual branching point dynamics, significant differences in nerve migration rate from the mean were only found in a few exceptions.ConclusionsThe results of this proof-of-concept study have demonstrated the feasibility of using in vivo confocal microscopy to study the migration rates of corneal subbasal nerves within large areas of the central human cornea (>1 mm2). The ability to monitor dynamic changes in the SNP opens a window to future studies of corneal nerve health and regenerative capacity in a number of systemic and ocular diseases. Since corneal nerves are considered part of the peripheral nervous system, this technique could also offer an objective diagnostic tool and biomarker for disease- or treatment-induced neuropathic changes.

Effective electroencephalogram based epileptic seizure detection using support vector machine and statistical moment’s features

Epilepsy is one of the widespread disorders. It is a noncommunicable disease that affects the human nerve system. Seizures are abnormal patterns of behavior in the electricity of the brain which produce symptoms like losing consciousness, attention or convulsions in the whole body. This paper demonstrates an effective electroencephalogram (EEG) based seizure detection method using discrete wavelet transformation (DWT) for signal decomposition to extract features. An automatic channel selection method was proposed by the researcher to select the best channel from 23 channels based on maximum variance value. The records were segmented into a nonoverlapping segment with long 1-S. The support vector machine (SVM) model was used to automatically detect segments that contain seizures, using both frequency and time domain statistical moment features. The experimental result was obtained from 24 patients in CHB-MIT database. The average accuracy is 94.1, sensitivity is 93.5, specificity is 94.6 and the false positive rate average is 0.054.

Magic Bullets: The Coming Age of Meaningful Pharmacological Control of the Corneal Responses to Injury and Disease.

Corneal injuries from chemical burns, mechanical trauma, infections, immunological rejections, surgical complications, and some diseases are commonly associated with persistent epithelial defects (PED), neurotrophic epitheliopathy, scarring fibrosis, corneal neovascularization (CNV), and/or corneal endothelial damage that lead to vision loss. Several Food and Drug Administration (FDA) approved medications have recently become available, are currently in clinical trials, or are likely to enter clinical trials in the near future. For example, a 2-week course of topical human recombinant nerve growth factor is frequently an effective treatment for corneal neurotrophic epitheliopathy associated with PEDs. Topical losartan, an angiotensin converting enzyme II receptor antagonist that also inhibits TGF beta signaling, has been shown to effectively decrease myofibroblast generation and scarring fibrosis in alkali burn injury and Descemetorhexis rabbit models. Small molecule topical tyrosine kinase inhibitors, such as sunitinib and axitinib, FDA approved as chemotherapeutic agents to treat specific cancers, have also been found to be effective topical inhibitors of CNV in animal and human trials. Rho-kinase inhibitors, such as ripasudil and netarsudil, that are currently approved agents for the treatment of glaucoma in some countries, have been shown to stimulate corneal endothelial proliferation in animal studies and human trials, and may accelerate the regeneration of Descemet's membrane. These agents, as well as other drugs in development, will be used in targeted combinations to treat corneal pathophysiology associated with epithelial healing disorders, stromal scarring fibrosis, CNV, and corneal endothelial injury during the next decade.

PSXI-7 Effects of Hericium Erinaceus on Health of Aged Dogs

Abstract Hericium erinaceus is a medicinal mushroom that has beneficial effects in human anti-oxidation, immune enhancement, and nerve growth factor stimulation. Aging-related benefits have also been described. The present study investigated the effect of H. erinaceus on aged dogs, with adult (5 years old) and aged (11 years old) animals untreated as controls (C1 and C2, respectively). Aged dogs were additionally treated with 0.4 g (T1) and 0.8 g (T2) H. erinaceus per metabolic body weight. In a two-choice preference test, the experimental diet with H. erinaceus was completely consumed more rapidly. No significant change in body weight, body condition score, and feces score were evident for 16 weeks. Complete blood counts and blood chemistry analyses were in normal ranges. These findings indicated that H. erinaceus was not detrimental to the general health of dogs. Metabolome profiles in sera were determined by nuclear magnetic resonance (NMR) imaging to investigate the metabolic change in dogs fed H. erinaceus. After 8 weeks, formate, ascorbate (vitamin C), acetone and choline concentrations were significantly increased. These compounds were also significantly increased after 16 weeks in the T2 group. Formate is influential in cell proliferation, acetone and choline are involved in lipid membrane formation, and ascorbate is essential for tissue repair. Additionally, choline and ascorbate are involved in antioxidant system. Collectively, the findings indicate the benefit of H. erinaceus to increase cell proliferation and tissue repair activity that might be related to enhancing an antioxidant activity in aged dogs.

A novel decellularized nerve graft for repairing peripheral nerve long gap injury in the rat

Decellularized nerve allografts are an alternative to autograft for repairing severe nerve injuries, since they have higher availability and do not induce rejection. In this study, we have assessed the regenerative potential of a novel decellularization protocol for human and rat nerves for repairing nerve resections, compared to the gold standard autograft. A 15-mm gap in the sciatic nerve was repaired with decellularized rat allograft (DC-RA), decellularized human xenograft (DC-HX), or fresh autograft (AG). Electrophysiology tests were performed monthly to evaluate muscle reinnervation, whereas histological and immunohistochemical analyses of the grafts were evaluated at 4 months. A short-term study was also performed to compare the differences between the two decellularized grafts (DC-RA and DC-HX) in early phases of regeneration. The decellularization process eliminated cellularity while preserving the ECM and endoneurial tubules of both rat and human nerves. Higher amount of reinnervation was observed in the AG group compared to the DC-RA group, while only half of the animals of the DC-HX showed distal muscle reinnervation. The density of myelinated axons was significantly higher in AG compared to both DC grafts, being this density significantly higher in DC-RA than in DC-HX. At short term, fibroblasts repopulated the DC-RA graft, supporting regenerated axons, whereas an important fibrotic reaction was observed around DC-HX grafts. In conclusion, the decellularized allograft sustained regeneration through a long gap in the rat although at a slower rate compared to the ideal autograft, whereas regeneration was limited or even failed when using a decellularized xenograft.

Sphingomyelinases in retinas and optic nerve heads: Effects of ocular hypertension and ischemia

Sphingomyelinases (SMase), enzymes that catalyze the hydrolysis of sphingomyelin to ceramide, are important sensors for inflammatory cytokines and apoptotic signaling. Studies have provided evidence that increased SMase activity can contribute to retinal injury. In most tissues, two major SMases are responsible for stress-induced increases in ceramide: acid sphingomyelinase (ASMase) and Mg2+-dependent neutral sphingomyelinase (NSMase). The purposes of the current study were to determine the localization of SMases and their substrates in the retina and optic nerve head and to investigate the effects of ocular hypertension and ischemia on ASMase and NSMase activities.Tissue and cellular localization of ASMase and NSMase were determined by immunofluorescence imaging. Tissue localization of sphingomyelin in retinas was further determined by Matrix-Assisted Laser Desorption/Ionization mass spectrometry imaging. Tissue levels of sphingomyelins and ceramide were determined by liquid chromatography with tandem mass spectrometry. Sphingomyelinase activities under basal conditions and following acute ischemic and ocular hypotensive stress were measured using the Amplex Red Sphingomyelinase Assay Kit. Our data show that ASMase is in the optic nerve head and the retinal ganglion cell layer. NSMase is in the optic nerve head, photoreceptor and retinal ganglion cell layers. Both ASMase and NSMase were identified in human induced pluripotent stem cell-derived retinal ganglion cells and optic nerve head astrocytes. The retina and optic nerve head each exhibited unique distribution of sphingomyelins with the abundance of very long chain species being higher in the optic nerve head than in the retina. Basal activities for ASMase in retinas and optic nerve heads were 54.98 ± 2.5 and 95.6 ± 19.5 mU/mg protein, respectively. Ocular ischemia significantly increased ASMase activity to 86.2 ± 15.3 mU/mg protein in retinas (P = 0.03) but not in optic nerve heads (81.1 ± 15.3 mU/mg protein). Ocular hypertension significantly increased ASMase activity to 121.6 ± 7.3 mU/mg protein in retinas (P < 0.001) and 267.0 ± 66.3 mU/mg protein in optic nerve heads (P = 0.03). Basal activities for NSMase in retinas and optic nerve heads were 12.3 ± 2.1 and 37.9 ± 8.7 mU/mg protein, respectively. No significant change in NSMase activity was measured following ocular ischemia or hypertension.Our results provide evidence that both ASMase and NSMase are expressed in retinas and optic nerve heads; however, basal ASMase activity is significantly higher than NSMase activity in retinas and optic nerve heads. In addition, only ASMase activity was significantly increased in ocular ischemia or hypertension. These data support a role for ASMase-mediated sphingolipid metabolism in the development of retinal ischemic and hypertensive injuries.

Brain MRI analysis using deep neural network for medical of internet things applications

Researchers are increasingly interested in leveraging the Internet of Things in medical and healthcare systems to provide better solutions such as remote health monitoring, personal fitness, and chronic disease management. A brain tumor is a potentially fatal cancer caused by the uncontrollable growth of brain cells that affects human blood cells and nerves. However, accurate classification of brain tumors is difficult due to the vastly different anatomical structures of healthy and tumorous tissues. We propose a framework for brain tumor localization and classification based on CenterNet. The proposed method uses the ResNet34 model with an attention block as a base network, which improves feature representation capacity by focusing on tumor locations and aids in tumor classification, particularly for a small tumor. Our method achieves 98.98% accuracy overall. Both qualitative and quantitative analysis demonstrated the efficacy of our approach for accurate detection and classification of the brain tumor than existing latest approaches.

MRI tractography reveals the human olfactory nerve map connecting the olfactory epithelium and olfactory bulb

The olfactory nerve map describes the topographical neural connections between the olfactory epithelium in the nasal cavity and the olfactory bulb. Previous studies have constructed the olfactory nerve maps of rodents using histological analyses or transgenic animal models to investigate olfactory nerve pathways. However, the human olfactory nerve map remains unknown. Here, we demonstrate that high-field magnetic resonance imaging and diffusion tensor tractography can be used to visualize olfactory sensory neurons while maintaining their three-dimensional structures. This technique allowed us to evaluate the olfactory sensory neuron projections from the nasal cavities to the olfactory bulbs and visualize the olfactory nerve maps of humans, marmosets and mice. The olfactory nerve maps revealed that the dorsal-ventral and medial-lateral axes were preserved between the olfactory epithelium and olfactory bulb in all three species. Further development of this technique might allow it to be used clinically to facilitate the diagnosis of olfactory dysfunction.

TH-256. Effects of 10 kHz subthreshold stimulation on human peripheral nerve activation

TH-256. Effects of 10 kHz subthreshold stimulation on human peripheral nerve activation

Biomechanical Testing of a Novel Device for Sutureless Nerve Repair.

Suboptimal nerve end alignment achieved with conventional nerve repair techniques may contribute to poor clinical outcomes. In this study, we introduce Nerve Tape®, a novel nerve repair device that integrates flexible columns of Nitinol microhooks within a biologic backing to entubulate, align, and secure approximated nerve ends. This study compares the repair strength of Nerve Tape with that of conventional microsuture repairs. Thirty small (2 mm) and 30 large (7 mm) diameter human cadaveric nerves were transected and repaired utilizing Nerve Tape or appropriate microsuture technique. Biomechanical testing was performed using a horizontal tensile tester. The repaired nerves were loaded until failure at a distraction rate of 40 mm/min, and the maximum failure load was determined. In the small nerve groups, the load-to-failure for Nerve Tape repairs (2.33 ± 0.66 N) was significantly higher than for suture repairs (1.22 ± 0.52 N; p < 0.05). In the large nerve groups, no significant difference in load-to-failure was found between Nerve Tape (7.45 ± 2.66 N) and suture repairs (5.82 ± 1.59 N: p = 0.12). Suture repairs tended to fail by rupture, whereas Nerve Tape failures resulted from microhook pullout. Nerve Tape is a novel nerve coaptation device that provides mechanical repair strength equal or greater to clinically relevant microsuture repairs.

P13. Transduction of the rat spinal cord using adenoassociated virus serotype 2.5

<h3>BACKGROUND CONTEXT</h3> Gene therapy is a method by which exogenous genes are introduced to treat disease or deliver drugs of interest. This is commonly done through either direct gene delivery in vivo or ex vivo through transduction of cells that are to be transplanted. There are several vectors for delivering genes, including viral vectors, naked plasmids, electroporation and lipid nanoparticles. Adeno-associated viruses (AAVs) are commonly used and considered to be well tolerated by the brain, muscles, nerves and multiple cell types. Rat Schwann cells are transduced efficiently by AAV1 whereas human Schwann cells are better transduced with AAV2 and 6. Rat nerves segments have demonstrated to be efficiently transduced by AAV1, 5, 7 and 9 whereas human nerves prefer AAV2. Many studies also agree that AAV1, 2, 4, 8 and 9 are optimal serotypes for CNS. We have utilized a novel viral vector, AAV serotype 2.5, that is a chimera of AAV2 vector modified with 5 amino acids from AAV1. AAV2.5 has shared characteristics of AAV1 and AAV2 with enhanced transduction for multiple cell types, such as in the muscle and articular tissue. Since AAV2.5 is not a naturally occurring virus, there is lower cross-reactivity to AAV2 antibodies. However, the ability of AAV2.5 to transduce tissues of the central (CNS) and peripheral nervous system (PNS) is not well understood. <h3>PURPOSE</h3> The purpose of this study is to determine the trophism and transduction efficiency of AAV2.5 for CNS and PNS tissue through in vitro transduction of dorsal root ganglion derived neurons, Schwann cells, and in vivo transduction of spinal cord. We predict that since AAV1 and AAV2 have known tropism for CNS and PNS cells to different extents depending on cell type, that the chimera AAV2.5 would be broadly effective. <h3>STUDY DESIGN/SETTING</h3> Cell culture and animal study. <h3>METHODS</h3> The cDNA encoding green fluorescent protein (GFP) was cloned into the conventional AAV packaging vector pTRUF2. For generation of self-complementing AAV vector plasmids, the cDNAs for GFP were directionally inserted into the SacII, NotI sites of pHpa-trs-SK plasmid. Transcription was driven by the cytomegalovirus promoter. Primary Schwann cells were isolated from the sciatic nerves of postnatal day 5 rat pups and dorsal root ganglion (DRG) neurons from embryonic day 15 rat pups. The cells were plated at a density of 125,000 cells per well and infected with 104 viral genomes per cell. For in vivo transduction of spinal cord tissue, 4 µL of 5 × 106– 5 × 1010vg/mL of AAV2.5-GFP was injected into 4 positions at T9. Immunostaining for markers of different spinal cord cell types colabeled with anti-GFP was done. <h3>RESULTS</h3> AAV2.5 was able to successfully infect DRG neurons and Schwann cells. AAV-2.5 vector was much more efficient than the commonly used AAV2 vector at transducing the Schwann cells. Cell survival and gene product production by AAV2.5 was greater than electroporation. When AAV2.5 -GFP was injected into the spinal cord there was a dose dependent increase in GFP expression by neurons and astrocytes up to 4 mm away from the injection site. <h3>CONCLUSIONS</h3> The study presents a novel vector for broad transduction in vivo or ex vivo of cells in the CNS and PNS. AAV2.5 was more efficient than the more commonly used AAV2 vector or electroporation. Since AAV2.5 is presently in phase 1 trials for osteoarthritis (NCT02790723), this vector type presents an interesting clinical translation opportunity for spinal cord and peripheral nerve injuries/diseases. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Human repair-related Schwann cells adopt functions of antigen-presenting cells in vitro.

The plastic potential of Schwann cells (SCs) is increasingly recognized to play a role after nerve injury and in diseases of the peripheral nervous system. Reports on the interaction between immune cells and SCs indicate their involvement in inflammatory processes. However, the immunocompetence of human SCs has been primarily deduced from neuropathies, but whether after nerve injury SCs directly regulate an adaptive immune response is unknown. Here, we performed comprehensive analysis of immunomodulatory capacities of human repair-related SCs (hrSCs), which recapitulate SC response to nerve injury in vitro. We used our well-established culture model of primary hrSCs from human peripheral nerves and analyzed the transcriptome, secretome, and cell surface proteins for pathways and markers relevant in innate and adaptive immunity, performed phagocytosis assays, and monitored T-cell subset activation in allogeneic co-cultures. Our findings show that hrSCs are phagocytic, which is in line with high MHCII expression. Furthermore, hrSCs express co-regulatory proteins, such as CD40, CD80, B7H3, CD58, CD86, and HVEM, release a plethora of chemoattractants, matrix remodeling proteins and pro- as well as anti-inflammatory cytokines, and upregulate the T-cell inhibiting PD-L1 molecule upon pro-inflammatory stimulation with IFNγ. In contrast to monocytes, hrSC alone are not sufficient to trigger allogenic CD4+ and CD8+ T-cells, but limit number and activation status of exogenously activated T-cells. This study demonstrates that hrSCs possess features and functions typical for professional antigen-presenting cells in vitro, and suggest a new role of these cells as negative regulators of T-cell immunity during nerve regeneration.