Intraepidermal Nerve Fiber Density Research Articles

Reduced gene expression of netrin family members in skin and sural nerve specimens of patients with painful peripheral neuropathies.

To investigate the expression of axon guidance cues in skin and sural nerve biopsies of patients with polyneuropathies (PNP) as potential markers of nerve de- and regeneration and inflammation. We prospectively recruited 88 patients with PNP and compared data between patient subgroups and healthy controls. All patients underwent skin punch and/or sural nerve biopsy at the lower leg and proximal thigh. We characterized gene expression profiles of netrin family members as target genes involved in neuronal de- and regeneration [netrin 1, deleted in colorectal cancer (DCC), uncoordinated5H2, neogenin 1 (NEO1), netrin G1, netrin G2] using quantitative real-time PCR. Gene expression of netrin 1 (p < 0.05 in proximal skin), DCC (p < 0.001 in distal skin), NEO1 (p < 0.05 in distal skin), netrin G1 (p < 0.05 in proximal and p < 0.01 in distal skin), and netrin G2 (p < 0.001 in distal skin) was lower in skin biopsies of patients with neuropathy compared to healthy controls. Gene expression of NEO1 (p < 0.05 in distal skin), netrin G2 (p < 0.05 in distal skin), and DCC (p < 0.05 in sural nerve) was lower in samples of patients with painful compared to painless PNP and also correlated positively with intraepidermal nerve fiber density. Skin and sural nerve gene expression of the investigated target genes did not differ between neuropathies of different etiologies. We show reduced cutaneous and neural axon guide expression, which may contribute to a dysregulation of nerve fiber de- and regeneration.

Protective effect of ibuprofen in a rat model of chronic oxaliplatin-induced peripheral neuropathy.

Despite extensive preclinical and clinical investigations, a clinically relevant neuroprotective agent against oxaliplatin-induced peripheral neuropathy, which affects the quality of life following chemotherapy, has not been identified. Epidemiological data suggest that ibuprofen may reduce the risk of neuropathy. Male rats were treated with oxaliplatin (n = 6), oxaliplatin and ibuprofen (n = 5) or vehicle (n = 5) every second day for 15days. Neuropathy was evaluated using mechanical detection thresholds (MDT) at the hind paw and sensory nerve conduction velocity (SNCV) in the tail nerve at baseline, right after and 3 weeks after the end of treatment. Intraepidermal nerve fibre density (IENFD) was evaluated in the hind paw and inflammation in the dorsal root ganglia 3 weeks after treatment. Inflammation in the dorsal root ganglia was assessed using quantitative real-time RT-PCR (qPCR) of the mRNA levels for the pro-inflammatory cytokines, TNF-α and IL-1β, and by immunohistochemical staining for Iba1+ macrophages. SNCV was reduced in rats treated with oxaliplatin and with oxaliplatin and ibuprofen compared to control rats 3 weeks after treatment. No differences were found for MDT 3 weeks after treatment. IENFD was reduced in rats treated with oxaliplatin. There was a trend towards up-regulation of TNF-α mRNA levels in rats treated with oxaliplatin and with oxaliplatin and ibuprofen. Morphological changes of Iba1+ macrophages suggested activation, but no differences were found in area fraction or size of macrophage cell bodies. The results did not support a neuroprotective effect of ibuprofen but indicated that inflammation may play a role in oxaliplatin-induced peripheral neuropathy.

Early changes in tests of peripheral nerve function during oxaliplatin treatment and their correlation with chemotherapy-induced polyneuropathy symptoms and signs.

Assessment of the severity of chronic peripheral neuropathy during oxaliplatin treatment is based on symptoms. Efforts to adjust the total dose of oxaliplatin to prevent severe neuropathy can be complicated by the worsening of neuropathy symptoms following treatment. Objective measures of the structure and function of peripheral nerves during early phases of treatment may aid in determining the optimal oxaliplatin dose in individual patients. Intraepidermal nerve fibre density (IENFD) has been suggested as an early marker of peripheral neuropathy. Sixty patients were examined before treatment and following 25% and 50% of the total planned oxaliplatin dose. Fifty-five of them were also examined at completion of chemotherapy and 6months later. IENFD in skin biopsies from the distal leg, nerve conduction studies and quantitative sensory testing at the dorsum of the foot were performed. Forty-six healthy subjects were examined at baseline and after 6 and 52weeks for comparison. Intraepidermal nerve fibre density was not reduced during treatment. Sural nerve amplitude and conduction velocity, vibration detection thresholds, mechanical detection threshold and cold detection threshold were significantly reduced during treatment. Compared to reference values and spontaneous changes in healthy subjects, the largest proportions of patients with deterioration were found for vibration detection thresholds followed by nerve conduction studies, mechanical detection threshold, cold detection threshold and IENFD. Significant changes were most pronounced for measures of large nerve fibre function, especially vibration sensation. Skin biopsies do not seem to provide a clinically relevant objective measure of peripheral nerve deterioration during oxaliplatin treatment.

Sensitive skin is a neuropathic disorder.

Sensitive skin is defined by the occurrence of unpleasant sensations such as tingling, burning, tautness, itching or pain. Mechanisms explaining sensitive skin are controversial, and many hypotheses have been proposed. Because sensitive skin is primarily characterized by a wide variety of neuropathic-like symptoms, it is highly likely that neurosensory dysfunction in the skin represents one of the pathological mechanisms of sensitive skin. This hypothesis does not exclude other explanations like role of keratinocyte, transient receptor potential channels, vasculature or environmental factors. Nevertheless, the role of the nervous system in the development of sensitive skin is crucial, and growing evidence supports this hypothesis. Pain and pruritus described by patients with sensitive skin correspond to neuropathic component, and its assessment shows an increase in neuropathic measures (DN-4, Douleur Neuropathique 4) compared with control. These sensations are similar to the sensations observed in small-fibre neuropathy (SFN), which is a group of disorders that affect thin nerve fibres. One study on the pathophysiology of sensitive skin demonstrated that intra-epidermal nerve fibre density, especially of peptidergic C-fibres, was lower in the sensitive skin group. A recent study showed a modification in heat-pain detection threshold in patients with sensitive skin. All these results indicate that C-fibre damage can help explain sensitive skin. Consequently, the role of the nervous system is increasingly obvious. Nevertheless, keratinocytes and other epidermal cells closely participate in sensory transduction. Therefore, the results of neurophysiological studies should be interpreted in the light of this information that the whole epidermis represents a huge polymodal nociceptor.

Pathophysiologic mechanisms of itch in bullous pemphigoid

One of the hallmarks of bullous pemphigoid (BP) is moderate to severe chronic itch. Managing this is difficult because little is known about the mechanisms of itch in BP. We sought to elucidate the pathophysiologic mechanisms of itch in BP. The expression of itch mediators in lesions of 24 patients with BP and 6 healthy individuals were examined through immunofluorescence staining. Furthermore, the expression of itch mediators and itch severity was correlated. Itch severity was correlated with eosinophils, substance P, neurokinin 1R, interleukin (IL) 31 receptor A, oncostatin M receptor-β, IL-13, periostin, and basophils. There was also a trend between itch severity and IL-31 expression. Most of the cells expressing IL-31 or neurokinin 1R were identified as eosinophils. Intraepidermal nerve fiber density was decreased. Other itch mediators, including mast cells, IL-4, thymic stromal lymphopoietin, transient receptor potential vanilloid 1 and ankyrin 1, and protease activated receptor 2 were not significantly correlated with itch severity. The relatively small sample size, the examination of protein expression exclusively through immunofluorescent analysis, and lack of functional assays in patients are the limitations. Multiple factors are involved in BP-associated itch, including eosinophils, substance P, neurokinin 1R, IL-31, IL-31 receptor A, oncostatin M receptor-β, IL-13, periostin, and basophils. They could be useful therapeutic targets.

Peripheral Sensitization and Loss of Descending Inhibition Is a Hallmark of Chronic Pruritus

Neurophysiological mechanisms leading to chronicity of pruritus are not yet fully understood and it is not known whether these mechanisms diverge between different underlying diseases of chronic pruritus (CP). This study aimed to detect such mechanisms in CP of various origins. A total of 120 patients with CP of inflammatory origin (atopic dermatitis), neuropathic origin (brachioradial pruritus), and chronic prurigo of nodular type, the latter as a model for chronic scratching, as well as 40 matched healthy controls participated in this study. Stimulation with cowhage induced a more intensive itch sensation compared with stimulation with other substances in all patient groups but not in healthy controls, arguing for sensitization of cutaneous mechano- and heat-sensitive C-fibers in CP. All patient groups showed a decreased intraepidermal nerve fiber density compared with controls. A decreased condition pain modulation effect was observed in all patient groups compared with controls, suggesting a reduced descending inhibitory system in CP. In sum, CP of different etiologies showed a mixed peripheral and central pattern of neuronal alterations, which might contribute to the chronicity of pruritus with no differences between pruritus entities. Our findings may contribute to the development of future treatment strategies targeting these pathomechanisms.

Functional and histological improvements of small nerve neuropathy after high-concentration capsaicin patch application: A case study

Introduction:Small fiber neuropathy has been found to occur in a large variety of pathological onditions, and the gold standard for diagnosis of small fiber neuropathy is skin biopsy. Sudorimetry is now considered an accurate technique to evaluate small fiber function with a good sensitivity and specificity for the diagnosis of small fiber neuropathy. Capsaicin high-concentration patch is approved for the treatment of peripheral neuropathic pain in adults either alone or in combination with other medicinal products for pain.Methods:We describe the case of a 50-year-old woman diagnosed with small fiber neuropathy. After 2 previous treatment failures, she was proposed a treatment with high-dose capsaicin patches on the sole of her foot. The patient experienced an important diminution of her neuropathic pain. There was a 50% decrease in the pain numeric scale. Electrochemical skin conductance and skin biopsy were repeated 3 months after patch application.Results:At 3 months, the patient then experienced an important diminution of her neuropathic pain, electrochemical skin conductance had normalized both in the hands and feet and intraepidermal nerve fiber density at distal leg increased almost reaching normal range.Conclusion:This case report shows the correlation between clinical improvement, electrochemical skin conductance normalization, and intraepidermal nerve fiber density improvement after a high-dose capsaicin patch in a patient with small fiber neuropathy.

Ryanodine Receptor to Mitochondrial Reactive Oxygen Species Pathway Plays an Important Role in Chronic Human Immunodeficiency Virus gp120MN-Induced Neuropathic Pain in Rats.

Chronic pain is one of the most common complaints in patients with human immunodeficiency virus (HIV)-associated sensory neuropathy. Ryanodine receptor (RyR) and mitochondrial oxidative stress are involved in neuropathic pain induced by nerve injury. Here, we investigated the role of RyR and mitochondrial superoxide in neuropathic pain induced by repeated intrathecal HIV glycoprotein 120 (gp120) injection. Recombinant HIV glycoprotein gp120MN was intrathecally administered to induce neuropathic pain. Mechanical threshold was tested using von Frey filaments. Peripheral nerve fiber was assessed by the quantification of the intraepidermal nerve fiber density in the skin of the hindpaw. The expression of spinal RyR was examined using Western blots. Colocalization of RyR with neuronal nuclei (NeuN; neuron marker), glial fibrillary acidic protein (GFAP; astrocyte marker), or ionizing calcium-binding adaptor molecule 1 (Iba1; microglia marker) in the spinal cord was examined using immunohistochemistry. MitoSox-positive profiles (a mitochondrial-targeted fluorescent superoxide indicator) were examined. The antiallodynic effects of intrathecal administration of RyR antagonist, dantrolene (a clinical drug for malignant hyperthermia management), or selective mitochondrial superoxide scavenger, Mito-Tempol, were evaluated in the model. We found that repeated but not single intrathecal injection of recombinant protein gp120 induced persistent mechanical allodynia. Intraepidermal nerve fibers in repeated gp120 group was lower than that in sham at 2 weeks, and the difference in means (95% confidence interval) was 8.495 (4.79-12.20), P = .0014. Repeated gp120 increased expression of RyR, and the difference in means (95% confidence interval) was 1.50 (0.504-2.495), P = .007. Repeated gp120 also increased mitochondrial superoxide cell number in the spinal cord, and the difference in means (95% confidence interval) was 6.99 (5.99-8.00), P < .0001. Inhibition of spinal RyR or selective mitochondrial superoxide scavenger dose dependently reduced mechanical allodynia induced by repeated gp120 injection. RyR and mitochondrial superoxide were colocalized in the neuron, but not glia. Intrathecal injection of RyR inhibitor lowered mitochondrial superoxide in the spinal cord dorsal horn in the gp120 neuropathic pain model. These data suggest that repeated intrathecal HIV gp120 injection induced an acute to chronic pain translation in rats, and that neuronal RyR and mitochondrial superoxide in the spinal cord dorsal horn played an important role in the HIV neuropathic pain model. The current results provide evidence for a novel approach to understanding the molecular mechanisms of HIV chronic pain and treating chronic pain in patients with HIV.

Biopsy-Proven Small-Fiber Neuropathy in Primary Sjögren's Syndrome: Neuropathic Pain Characteristics, Autoantibody Findings, and Histopathologic Features.

Painful small-fiber neuropathies (SFNs) in primary Sjögren's syndrome (SS) may present as pure or mixed with concurrent large-fiber involvement. SFN can be diagnosed by punch skin biopsy results that identify decreased intra-epidermal nerve-fiber density (IENFD) of unmyelinated nerves. We compared 23 consecutively evaluated patients with SS with pure and mixed SFN versus 98 patients without SFN. We distinguished between markers of dorsal root ganglia (DRG) degeneration (decreased IENFD in the proximal thigh versus the distal leg) versus axonal degeneration (decreased IENFD in the distal leg versus the proximal thigh). There were no differences in pain intensity, pain quality, and treatment characteristics in the comparison of 13 patients with pure SFN versus 10 patients with mixed SFN. Ten patients with SFN (approximately 45%) had neuropathic pain preceding sicca symptoms. Opioid analgesics were prescribed to approximately 45% of patients with SFN. When compared to 98 patients without SFN, the 23 patients with SFN had an increased frequency of male sex (30% versus 9%; P < 0.01), a decreased frequency of anti-Ro 52 (P = 0.01) and anti-Ro 60 antibodies (P = 0.01), rheumatoid factor positivity (P < 0.01), and polyclonal gammopathy (P < 0.01). Eleven patients had stocking-and-glove pain, and 12 patients had nonstocking-and-glove pain. Skin biopsy results disclosed patterns of axonal (16 patients) and DRG injury (7 patients). SS SFN had an increased frequency among male patients, a decreased frequency of multiple antibodies, frequent treatment with opioid analgesics, and the presence of nonstocking-and-glove pain. Distinguishing between DRG versus axonal injury is significant, especially given that mechanisms targeting the DRG may result in irreversible neuronal cell death. Altogether, these findings highlight clinical, autoantibody, and pathologic features that can help to define mechanisms and treatment strategies.

Secreted factors from cultured dental pulp stem cells promoted neurite outgrowth of dorsal root ganglion neurons and ameliorated neural functions in streptozotocin-induced diabetic mice.

Aims/IntroductionTransplantation of stem cells promotes axonal regeneration and angiogenesis in a paracrine manner. In the present study, we examined whether the secreted factors in conditioned medium of stem cells from human exfoliated deciduous teeth (SHED‐CM) had beneficial effects on diabetic polyneuropathy in mice.Materials and MethodsConditioned medium of stem cells from human exfoliated deciduous teeth was collected 48 h after culturing in serum‐free Dulbecco's modified Eagle's medium (DMEM), and separated into four fractions according to molecular weight. Dorsal root ganglion neurons from C57BL/6J mice were cultured with SHED‐CM or DMEM to evaluate the effect on neurite outgrowth. Streptozotocin‐induced diabetic mice were injected with 100 μL of SHED‐CM or DMEM into the unilateral hindlimb muscles twice a week over a period of 4 weeks. Peripheral nerve functions were evaluated by the plantar test, and motor and sensory nerve conduction velocities. Intraepidermal nerve fiber densities, capillary number‐to‐muscle fiber ratio, capillary blood flow and morphometry of sural nerves were also evaluated.ResultsConditioned medium of stem cells from human exfoliated deciduous teeth significantly promoted neurite outgrowth of dorsal root ganglion neurons compared with DMEM. Among four fractions of SHED‐CM, the only fraction of <6 kDa promoted the neurite outgrowth of dorsal root ganglion neurons. In addition, SHED‐CM significantly prevented decline in sensory nerve conduction velocities compared with DMEM in diabetic mice. Although SHED‐CM did not improve intraepidermal nerve fiber densities or morphometry of sural nerves, SHED‐CM ameliorated the capillary number‐to‐muscle fiber ratio and capillary blood flow.ConclusionsThese results suggested that SHED‐CM might have a therapeutic effect on diabetic polyneuropathy through promoting neurite outgrowth, and the increase in capillaries might contribute to the improvement of neural function.

Pain-associated Mediators and Axon Pathfinders in Fibromyalgia Skin Cells

To investigate whether the expression of cytokine, nociception-associated ion channel, and axon guidance genes in patients with skin cell fibromyalgia syndrome (FMS) differs from healthy controls, potentially contributing to pain and small-fiber degeneration in FMS. We prospectively recruited 128 patients and 26 healthy controls. All study participants underwent neurological examination, and a skin punch biopsy was obtained from the lateral calf and thigh. Skin samples were processed to histologically determine intraepidermal nerve fiber density (IENFD) and for primary fibroblast and keratinocyte cell cultures. Gene expression of selected pro- and antiinflammatory cytokines, nociception-associated ion channels, and axon guidance cues was assessed with quantitative real-time PCR. In fibroblasts, transforming growth factor-ß1 (TGF-ß1) gene expression was higher in patients with FMS compared to controls (calf and thigh: p < 0.001). Also, expression was higher in patients than in controls for these variables: hyperpolarization-activated cyclic nucleotide-gated ion channel 2 (calf: p < 0.01), ephrin-A4 (EFNA4; calf: p < 0.05, thigh: p < 0.001), and ephrin receptor-A4 (EPHA4; thigh: p < 0.05). In keratinocytes, interleukin 10 gene expression was higher in patients with FMS than in controls (thigh: p < 0.05). While no intergroup difference was found for nociception-associated ion channels, EFNA4 and EPHA4 (calf: p < 0.01 each) expression was higher in patients with FMS than in controls. Axon guide expression did not correlate with IENFD. In FMS, skin cells may contribute to cutaneous nociception by differentially expressing membrane-bound and soluble pain mediators and axon pathfinders.

Early nerve fibre regeneration in individuals with type 1 diabetes after simultaneous pancreas and kidney transplantation

Aims/hypothesisThe study aimed to assess the impact on neuropathy of simultaneous pancreas and kidney transplantation (SPK) in individuals with type 1 diabetes.MethodsThis longitudinal observational study examined neuropathic symptoms, deficits, quantitative sensory testing, neurophysiology, corneal confocal microscopy and skin biopsy results in 32 healthy (non-diabetic) control participants, 29 individuals with type 1 diabetes and severe diabetic peripheral neuropathy [DPN] and 36 individuals with type 1 diabetes after SPK.ResultsFollowing SPK, HbA1c, eGFR, triacylglycerols and HDL improved significantly (all p < 0.05). Compared with the DPN group, which remained unchanged over the 36 month study period, corneal confocal microscopy assessments improved over 36 months following SPK, with increasing corneal nerve fibre density of 5/mm2 (95% CI 1.8, 8.2; p = 0.003) and corneal nerve fibre length of 3.2 mm/mm2 (95% CI 0.9, 5.5; p = 0.006). The Neuropathy Symptom Profile and peroneal nerve conduction velocity also improved significantly by 36 months compared with DPN (2.5; 95% CI 0.7, 4.3; p = 0.008 and 4.7 m/s; 95% CI 2.2, 7.4; p = 0.0004, respectively), but with a temporal delay compared with the corneal confocal microscopy assessments. Intraepidermal nerve fibre density did not change following SPK; however, mean dendritic length improved significantly at 12 (p = 0.020) and 36 (p = 0.019) months. In contrast, there were no changes in the Neuropathy Disability Score, quantitative sensory testing or cardiac autonomic function assessments. Except for a small decrease in corneal nerve fibre density in the healthy control group, there were no changes in any other neuropathy measure in the healthy control or DPN groups over 36 months.Conclusions/interpretationSPK is associated with early and maintained small nerve fibre regeneration in the cornea and skin, followed by an improvement in neuropathic symptoms and peroneal nerve conduction velocity.

Small fiber neuropathy and phosphorylated alpha-synuclein in the skin of E46K-SNCA mutation carriers

Background and objectiveIn 2004 we described the E46K mutation in alpha-synuclein gene (E46K-SNCA), a rare point mutation causing an aggressive Lewy body disease with early prominent non-motor features and small fiber denervation of myocardium. Considering the potential interest of the skin as a target for the development of biomarkers in Parkinson's Disease (PD), in this work we aimed to evaluate structural and functional integrity of small autonomic nerve fibers and phosphorylated alpha-synuclein (p-synuclein) deposition in the skin of E46K-SNCA carriers as compared to those observed in parkin gene mutation (PARK2) carriers and healthy controls. Patients and methodsWe studied 7 E46K-SNCA carriers (3 dementia with Lewy bodies, 2 pure autonomic failure, 1 PD and 1 asymptomatic), 2 PARK2 carriers and 2 healthy controls to quantify intraepidermal nerve fiber density and p-synuclein deposition with cervical skin punch biopsies (immunohistochemistry against anti PGP9.5/UCHL-1, TH and p-synuclein) and sudomotor function with electrochemical skin conductance (ESC) (SudoScan). ResultsAll E46K-SNCA carriers had moderate to severe p-synuclein deposits and small fiber neurodegeneration in different epidermal and dermal structures including nerve fascicles and glands, especially in carriers with Pure Autonomic Failure, while p-synuclein aggregates where absent in healthy controls and in one of two PARK2 carriers. The severity of the latter skin abnormalities in E46K-SNCA were correlated with sudomotor dysfunction (lower ESC) in hands (p = 0.035). InterpretationThese results together with our previous findings support the relevance of E46K-SNCA mutation as a suitable model to study small fiber neuropathy in Lewy body diseases.

320-OR: Axonal Swellings in Diabetic Patients With and Without Neuropathy

Background: Up to 50% of patients with diabetes develop peripheral neuropathy (DPN). DPN is associated with low intraepidermal nerve fiber density (IENFD), and morphometric degenerative changes such as axonal swellings are also observed. The relationship of swellings to DPN status has not yet been delineated. Methods: In total 207 patients with type 2 diabetes and 24 age- and gender-matched healthy controls were included in the study. Included in the analysis were participants whose IENFD was &amp;gt;0.5 fiber/mm, thus allowing swelling ratio calculation (n=156). The patients underwent a rigorous DPN assessment, including a neurological examination, nerve conduction studies, skin biopsy and quantitative sensory testing. Patients were divided into three groups: without DPN (n=35), with painless DPN (n=72), and with painful DPN (n=100). Axonal swellings were defined as enlargements on nerve fibers exceeding 1.5 μm in diameter. Swelling ratio was obtained by dividing the number of swellings with IENFD. Results: Median (IQR) IENFD was significantly different between the groups: without DPN: 6.15 (4.9;8.08) fibers/mm; painless DPN: 1.65 (1.07;2.73); painful DPN: 1.4 (0.80;2.12); controls: 5.8 (4.95;8.0), P&amp;lt;0.01. Median swelling ratios were also significantly different between groups: without DPN: 0.34 (0.16;0.55); painless DPN: 0.14 (0;0.55); painful DPN: 0 (0;0.31); and controls: 0 (0;0.6), p&amp;lt;0.01. This difference disappeared when only including patients with somewhat preserved IENFD (IENFD &amp;gt;2) (P=0.4). Patients with diabetes and IENFD &amp;gt;2 had higher swelling ratio compared with healthy controls, regardless of neuropathy status (P&amp;lt;0.01). Swelling ratio did not correlate with BMI, diabetes duration, pain or Toronto Clinical Neuropathy score (P&amp;gt;0.1), but did correlate negatively with HbA1c levels when only including all patients with IENFD &amp;gt;0.5 (P=0.04). Conclusions: Axonal swellings are present in most diabetic patients with preserved IENFD and may indicate morphological changes of nerve fibers. Disclosure P. Karlsson: Advisory Panel; Self; Grünenthal. S. Gylfadottir: None. S. Tesfaye: Advisory Panel; Self; Mitsubishi Tanabe Pharma Corporation, WÖRWAG Pharma. Speaker's Bureau; Self; AstraZeneca, Merck &amp; Co., Inc., NAPP Pharmaceuticals Limited, Neurometrix, Novo Nordisk Inc., Pfizer Inc. Other Relationship; Self; Impeto Medical. A.S. Rice: Research Support; Self; Orion. Other Relationship; Self; Imperial College Consultants, Spinifex/Novartis. J.R. Nyengaard: None. T.S. Jensen: None. D. Bennett: Consultant; Self; Lilly Diabetes, Orion, Theranexus. A. Themistocleous: None. Funding Novo Nordisk Foundation (NNF14OC0011633); Danish Diabetes Academy (to P.K.)

558-P: Rate of Progression of Utah Early Neuropathy Symptom Score in Diabetic Neuropathy

The Utah Early Neuropathy Scale (UENS) is a brief, validated exam scale focused on injury to small diameter nociceptive fibers. Twenty-four of 42 possible points are related to measurement of length dependent loss of pin sensation in legs and feet. While the UENS has been accepted as a standard clinical measure for diagnosis of small fiber neuropathy, its utility as a primary outcome measure in clinical trials has not been evaluated. Here we report natural history progression of the UENS. In an NIDDK DP3 single center study, 190 patients with diabetes were screened for neuropathy using Toronto criteria, then 83 found to have neuropathy were followed longitudinally at 9-month intervals for up to 27 months using a variety of clinical and ancillary measures, including the UENS. Among those with neuropathy, baseline UENS score significantly correlated with scores of symptom questionnaires including the Norfolk Quality of Life-Diabetes Neuropathy (NQoL-DN) and the NTSS-6; with nerve conduction study measures including sural sensory amplitude, peroneal amplitude and proximal conduction velocity; with intraepidermal nerve fiber density (IENFD) from distal thigh and distal leg 3m punch skin biopsies; but not with confocal corneal microscopy measures of nerve fiber length and density. Overall, 75 participants were followed for 9 months, and 56 for at least 18 months for a total of 149 9-month segments. UENS worsened (increased) 1.08 (+/- StDev 3.51) points per 9-month segment overall. For those followed at least 18 months, there was a 2.2 (+/-4.1) point increase over this period. Change in UENS significantly correlated with change in NQoL-DN and IENFD, among other measures. The UENS is an objective, responsive, validated clinical instrument for which a linear natural progression slope can be measured, and would be an appropriate primary endpoint in small fiber neuropathy clinical trials. Disclosure J. Singleton: None. P.E. Hauer: None. C. Revere: None. S.C. Foster-Palmer: None. A.B. Aperghis: None. A. Smith: Consultant; Self; Alexion Pharmaceuticals, Inc., Disarm, Regenesis. Funding National Institutes of Health (DP3DK104394)

325-OR: Early Parallel Progression of Peripheral and Cardiac Autonomic Nerve Dysfunction in Recent-Onset Type 1 Diabetes Patients

We previously demonstrated an early parallel involvement of small and large fibers in recent-onset type 2 diabetes. Here we hypothesized that this pattern may also be pertinent to type 1 diabetes (T1D). Therefore, motor and sensory nerve conduction velocity (MNCV, SNCV), vibration perception thresholds (VPT), thermal detection thresholds (TDT), intraepidermal nerve fiber density (IENFD), and heart rate variability (HRV) were assessed in participants with T1D from the German Diabetes Study (GDS) at baseline (diabetes duration ≤1 year) and in glucose-tolerant controls: CON/T1D-B: n=96/360; age [median (1st; 3rd quartile)]: 34.5 (26.0; 46.8)/34.6 (26.5; 45.3) years; male: 72/58%; BMI: 25.0 (22.9; 28.3)/24.0 (22.0 (22.0; 27.0) kg/m²; diabetes duration: -/173 (114; 173) days; HbA1c: 5.1 (5.0; 5.3)/6.4 (5.9; 7.2)%; M-value (hyperinsulinemic-euglycemic clamp): 11.6 (9.1; 13.6)/8.2 (6.5; 10.4) mg*kg-1*min-1. T1D-B showed lower peroneal MNCV ([mean±SEM]: 45.8±0.2 vs. 47.0±0.3 m/s), median MNCV (55.1±0.2 vs. 56.0±0.7 m/s), and IENFD (10.0±0.5 vs. 11.2±0.5 fibers/mm) than CON (P&amp;lt;0.05). In T1D, a deterioration from baseline to 5 years (n=151) was noted for ulnar and median MNCVs and SNCVs (e.g., ulnar MNCV: 57.4±0.4 vs. 56.3±0.3 m/s), malleolar VPT (0.76±0.07 vs. 1.12±0.12 µm), and HRV indices (e.g., standard deviation of normal RR intervals (SDNN): 69.3±2.4 vs. 62.0±2.1 ms; root mean square of successive differences (RMSSD): 42.8±2.3 vs. 34.7±2.0 ms) (all P&amp;lt;0.05). Peroneal MNCV, sural SNCV, and TDT remained unchanged. The decline in MNCV was associated with an increase in HbA1c (e.g., median nerve: β=-0.316, P=0.004) and the deterioration in HRV with decreasing M-value (e.g., SDNN: β=0.246, P=0.041). In conclusion, within the first 5-6 years of type 1 diabetes despite good glycemic control, the deterioration in median and ulnar MNCV was related to worsening HbA1c levels, while cardiac autonomic dysfunction progressed in relation to increasing insulin resistance. Disclosure G.J. Bönhof: None. A. Strom: None. O.P. Zaharia: None. J. Szendroedi: None. K. Muessig: None. M. Roden: Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Poxel SA, Servier. Board Member; Self; Eli Lilly and Company. Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Sanofi. Speaker's Bureau; Self; Novo Nordisk Inc. D. Ziegler: Advisory Panel; Self; Allergan, TrigoCare. Consultant; Self; Mitsubishi Tanabe Pharma Corporation, Mylan, Novartis Pharmaceuticals Corporation, Wörwag. Speaker's Bureau; Self; Berlin-Chemie AG. Funding German Ministry of Culture and Science of the State of North Rhine-Westphalia; German Federal Ministry of Health; German Federal Ministry of Education and Research

564-P: Secreted Factors from Dental Pulp Stem Cells Ameliorated Neural Functions in Streptozotocin-Induced Diabetic Mice

Aims/Introduction: We previously reported that stem cell transplantation into limb skeletal muscle improved diabetic polyneuropathy (DPN) in diabetic animal models. In this study, we examined whether the secreted factors from stem cells from human exfoliated deciduous teeth (SHED) had beneficial effects on DPN. Materials and Methods: The conditioned medium from SHED(SHED-CM) was collected 48 hours after culturing in serum-free DMEM and was separated into four fractions according to molecular weight. Dorsal root ganglion (DRG) neurons isolated from C57BL/6J mice were cultured with SHED-CM, each fraction of SHED-CM or DMEM. Streptozotocin induced diabetic mice were injected with 100µl of SHED-CM or DMEM into unilateral hindlimb muscles twice a week over 4 weeks. Peripheral nerve functions were evaluated by the plantar test and motor and sensory nerve conduction velocities (MNCV and SNCV). Intraepidermal nerve fiber densities (IENFDs), capillary number-to-muscle fiber ratio (CNMFR) and morphometry of sural nerves were also evaluated. The angiogenic profile of SHED-CM was evaluated by MTT, transwell migration, and wound healing assay using human umbilical vein endothelial cells (HUVECs). Results: SHED-CM significantly promoted neurite outgrowth of DRG neurons. Only less than 6 kDa of SHED-CM promoted the neurite outgrowth. SHED-CM significantly prevented decline in SNCVs compared with DMEM in diabetic mice. SHED-CM did not cause any change in MNCVs or sensory functions. Though SHED-CM did not improve IENFDs or morphometry of sural nerves, CNMFR was ameliorated by the administration of SHED-CM. SHED-CM significantly increased the proliferation and the migration of HUVECs. Conclusions: These results suggested that SHED-CM had the therapeutic effect on DPN by promoting neurite outgrowths and improving microcirculation in peripheral nerves. Disclosure E. Miura-Yura: None. S. Tsunekawa: None. K. Naruse: None. M. Kawai: None. M. Kato: None. H. Shimoda: None. Y. Yamada: None. M. Motegi: None. S. Asano: None. T. Himeno: None. M. Kondo: None. Y. Kato: Speaker's Bureau; Self; Merck &amp; Co., Inc. J. Nakamura: Research Support; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Eli Lilly and Company, Japan Tobacco Inc., Kissei Pharmaceutical Co., Ltd., Merck Sharp &amp; Dohme Corp., Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi K.K., Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited. Speaker's Bureau; Self; Astellas Pharma Inc., AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Eli Lilly and Company, Kowa Pharmaceu. Co. Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi K.K., Takeda Pharmaceutical Company Limited, Terumo Medical Corporation. H. Kamiya: Speaker's Bureau; Self; Astellas Pharma Inc., Eli Lilly Japan K.K., MSD K.K., Novartis Pharma K.K., Novo Nordisk Oharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K.K.

Non-invasive assessment of chemotherapy-induced peripheral neuropathy using neuromuscular ultrasound in breast cancer patients.

e23152 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting toxicity for breast cancer patients that leads to early treatment discontinuation and worse outcomes. Neuromuscular ultrasound (NMUS) is a non-invasive assessment of peripheral nerves that has not been studied in taxane CIPN. Methods: This cross-sectional study enrolled breast cancer patients with subjective complaints of CIPN symptoms during or after taxane chemotherapy and compared nerve cross-sectional area (CSA) by NMUS with historical values in 120 healthy adults. Findings were correlated with self-reported symptom scale (EORTC-QLQ CIPN20, range 0-72, higher more severe); nerve conduction studies; and skin biopsies for intraepidermal nerve fiber density (IENF). Results: We evaluated 20 participants (mean 55.4 ± 10.5 yrs) with NMUS at 74 nerve sites after median 3.7 months (IQR 1.0-6.1) since last taxane (paclitaxel 10, docetaxel 8, nab-paclitaxel 2). Participants reported moderate-to-severe CIPN symptoms which were predominantly sensory (19.1 ±4.9, max 32) as opposed to motor (15.6 ±5.8, max 32) or autonomic (3.3 ±1.6, max 8). Sural sensory nerve CSA was 1.2 mm2 smaller than in historical controls (4.1 vs. 5.3 mm2, 2-sample t-test p = 0.005) and decreased with more days from last taxane (Spearman’s r -0.46, p = 0.04). Tibial motor nerve was not significantly different from controls (p = 0.35). Median nerve CSA was enlarged at the distal wrist crease entrapment site (12.5 vs 10.1, p = 0.03). Older age was associated with smaller sural CSA (r = -0.72, p &lt; 0.001). When controlling for age and days from last taxane, for each 1mm2 decrease in sural CSA, distal IENF reduced by 2.1 nerve/mm2 (p = 0.04, R2 = 0.30). Conclusions: NMUS showed expected sensory predominant distal axonopathy in taxane CIPN. Evaluation of nerve CSA by non-invasive NMUS may serve as an objective point-of-care assessment to risk-stratify women with taxane CIPN prior to the development of debilitating symptoms. Clinical trial information: NCT03139435. [Table: see text]

Therapeutic effects of stem cells from human exfoliated deciduous teeth on diabetic peripheral neuropathy

ObjectiveTo evaluate the therapeutic potential of stem cells from human exfoliated deciduous teeth (SHED) for diabetic peripheral neuropathy.MethodsThe biological characteristics of SHED were identified by flow cytometric study and evaluation of differentiation potential. Using high-fat feeding, diabetes was induced in GK rats, and SHED were transplanted into the caudal veins of these rats. Immunohistochemical analysis was used to compare the capillary to muscle fiber ratio and intra-epidermal nerve fiber density between SHED- and saline-treated diabetic rats. Further, the expressions of angiogenesis-related and neurotrophic factors were quantified by real-time PCR and western blot.ResultsSHED had a capacity of multiple differentiation and shared typical characteristics of mesenchymal stem cells. SHED transplantation relieved diabetic neuropathic pain, enabled functional recovery of the peripheral nerves, and increased the capillary to muscle fiber ratio and intra-epidermal nerve fiber density compared to the saline group and normal controls. Real-time PCR results showed that the expressions of CD31, vWF, bFGF, NGF, and NT-3 in the skeletal muscles were higher in the SHED group than in the saline groups. Western blot results indicated that the levels of the CD31 and NGF proteins were higher in the SHED transplantation group than the saline group.ConclusionSHED transplantation ameliorated diabetic peripheral neuropathy in diabetic GK rats. Thus, systemic application of SHED could be a novel strategy for the treatment of diabetic peripheral neuropathy.

Pharmacologic Inhibition of Porcupine, Disheveled, and β-Catenin in Wnt Signaling Pathway Ameliorates Diabetic Peripheral Neuropathy in Rats

Wnt signaling pathway has been investigated extensively for its diverse metabolic and pain-modulating mechanisms; recently its involvement has been postulated in the development of neuropathic pain. However, there are no reports as yet on the involvement of Wnt signaling pathway in one of the most debilitating neurovascular complication of diabetes, namely, diabetic peripheral neuropathy (DPN). Thus, in the present study, involvement of Wnt signaling was investigated in DPN using Wnt signaling inhibitors namely LGK974 (porcupine inhibitor), NSC668036 (disheveled inhibitor), and PNU74654 (β-catenin inhibitor). Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg/kg) to male Sprague–Dawley rats. Diabetic rats after 6 weeks of diabetes induction showed increased expression of Wnt signaling proteins in the spinal cord (L4–L6 lumbar segment), dorsal root ganglions and sciatic nerves. Subsequent increase in inflammation, endoplasmic reticulum stress and loss of intraepidermal nerve fiber density was also observed, leading to neurobehavioral and nerve functional deficits in diabetic rats. Intrathecal administration of Wnt signaling inhibitors (each at doses of 10 and 30 µmol/L) in diabetic rats showed improvement in pain-associated behaviors (heat, cold, and mechanical hyperalgesia) and nerve functions (motor, sensory nerve conduction velocities, and nerve blood flow) by decreasing the expression of Wnt pathway proteins, inflammatory marker, matrix metalloproteinase 2, endoplasmic reticulum stress marker, glucose-regulated protein 78, and improving intraepidermal nerve fiber density. All these results signify the neuroprotective potential of Wnt signaling inhibitors in DPN. PerspectiveThis study emphasizes the involvement of Wnt signaling pathway in DPN. Blockade of this pathway using Wnt inhibitors provided neuroprotection in experimental DPN in rats. This study may provide a basis for exploring the therapeutic potential of Wnt inhibitors in DPN patients.