Anti-myelin-associated glycoprotein neuropathy: Where do we stand?

Myelin-associated glycoprotein (MAG) is a transmembrane glycoprotein concentrated in periaxonal Schwann cell and oligodendroglial membranes of myelin sheaths that serves as an antigen for immunoglobulin M (IgM) monoclonal antibodies. Individuals who harbor anti-MAG antibodies classically develop a progressive autoimmune peripheral neuropathy characterized clinically by ataxia, distal sensory loss, and gait instability, and electrophysiologically by distally accentuated conduction velocity slowing. Although off-label immunotherapy is common, there are currently no proven effective disease-modifying therapeutics, and most patients experience slow accumulation of disability over years and decades. The typically slowly progressive nature of this neuropathy presents unique challenges when trying to find effective anti-MAG therapeutic agents. Drug development has also been hampered by the lack of validated outcome measures that can detect clinically meaningful changes in a reasonable amount of time as well as by the lack of disease activity biomarkers. In this invited review, we provide an update on the state of clinicometric outcome measures and disease activity biomarkers in anti-MAG neuropathy. We highlight the insensitivity of widely used existing clinicometric outcome measures such as the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score as well as the INCAT sensory subscore in anti-MAG neuropathy, referencing the two previous negative randomized controlled clinical trials evaluating rituximab. We then discuss newly emerging candidate therapeutic agents, including tyrosine kinase inhibitors and enhanced B-cell-depleting agents, among others. We conclude with a practical approach to the evaluation and management of anti-MAG neuropathy patients.

Linezolid-related adverse effects in the treatment of rifampicin resistant tuberculosis: a retrospective study.

Linezolid (LZD) is an effective drug in treating multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis. This study aimed to evaluate the safety of LZD in the treatment of patients with rifampicin resistant tuberculosis. This was a multicenter retrospective study. A total of 184 patients of the rifampicin resistant tuberculosis patients treated with LZD from Jan 2018 to Apr 2020 in three hospitals were involved, and their clinical symptoms were recorded and analyzed. Meanwhile, the types and incidence of adverse effects associated with LZD were evaluated. It showed that peripheral neuritis (51, 27.7%) and hemochromatosis (42, 22.8%) were the most common adverse effects observed among these patients. The median time of symptoms after LZD treatment was 45.5 and 120.0 days, respectively. Furthermore, female patients had a significantly higher risk for leukopenia (P = 0.002) and hemochromatosis (P = 0.033) when compared with male patients. History of underlying disease was the risk factor for thrombocytopenia (P = 0.022). Patients with long duration of medication (RR = 1.004, 95%CI: 1.002-1.006, P < 0.001) and daily dosage ≥600mg (RR = 3.059, 95%CI: 1.238-7.558, P = 0.015) were at higher risk of hemochromatosis. Age was the risk factor for rash (P = 0.008) and nausea and vomiting (P = 0.018). In addition, LZD administration time was the risk factor for optic neuritis (P < 0.001) and peripheral neuritis (P < 0.001). LZD can cause adverse symptoms in patients with rifampicin resistant tuberculosis. Gender, history of underlying disease, LZD use time, LZD dosage, and age are the risk factors in the LZD treatment of these patients. During medication, bone marrow suppression and neuropathy should be closely monitored. This study could potentially provide useful information for the clinical practice.

ATYPICAL FORMS OF EYE TOXOPLASMOSIS IN CHILDHOOD. CASE REPORTS.

AIM: To present an outline of acquired atypical forms of ocular toxoplasmosis (OT) in childhood, with reference to the 100th anniversary of the discovery of this etiology by Professor Janků from Czechoslovakia, who was first to describe the clinical congenital picture of OT characterised by macular scar. MATERIAL AND METHODS: Symptoms of intraocular bilateral neuritis appeared in a 6-year-old girl, with visual acuity (VA) bilaterally 0.1. Toxoplasmic etiology was demonstrated in laboratory tests, and the patient was immunocompetent. Following treatment with macrolide antibiotic and parabulbar application of corticosteroid, the condition was normalised stably at VA 1.0 in both eyes. Bilateral retinal vasculitis was determined in an 8-year-old boy, with VA of 0.25 in the right eye and 0.25 in the left, with a medical history of strabismus detected after suffering from varicella. The examination for toxoplasmosis was negative, but pronounced general hypogammaglobulinaemia classes IgG, IgM and IgA was detected. Immunosuppressive and immunomodulatory therapy did not produce the desired effect, and the condition progressed to retinochoroiditis. Due to blindness and dolorous glaucoma, enucleation of the right eye was performed at the age of 15 years. Histologically toxoplasmic cysts with bradyzoites were detected, a subsequent laboratory test demonstrated toxoplasmic etiology upon a background of persistent regressing hypogammaglobulinaemia. General anti-toxoplasma and subsequent immunosuppressive treatment did not produce the desired effect, and at the age of 22 years the patient lost his sight also in the left eye. CONCLUSION: Atypical form of OT intraocular neuritis in an immunocompetent patient had a favourable course, whereas retinal vasculitis with retinochoroiditis in a temporarily immunocompromised patient ended in bilateral blindness.

Uncommon cause of trigeminal neuritis and central nervous system involvement by herpes labialis: a case report.

BACKGROUND: Trigeminal neuropathy is characterized by numbness in the region innervated by the trigeminal nerves, with or without neuropathic weakness in the muscles of mastication. Trigeminal neuritis is a form of trigeminal neuropathy in which the lesion is caused by an inflammation. Herein, we report a patient with trigeminal neuritis due to central nervous system (CNS) involvement of herpes labialis (HL) infection, which was successfully treated with anti-viral and anti-inflammatory agents. CASE PRESENTATION: A young healthy female presented with numbness in the left hemiface for two weeks. She had a preceding typical HL infection on left facial lip one week before the sensory symptom onset. Brain magnetic resonance imaging revealed high signal intensities and asymmetrical thickening with enhancement along the cisternal segment of the left trigeminal nerve. Additionally, brain MR angiography showed multifocal stenoses in the M1 segment of the middle cerebral artery and the cavernous portion of the internal carotid artery. Cerebrospinal fluid (CSF) examination showed mild pleocytosis with normal protein level, glucose ratio, but CSF polymerase chain reaction assay for specific anti-viral antibodies including herpes simplex virus was negative, and CSF culture also did not identify a specific pathogen. The results of serologic testing including tumor markers and autoimmune markers were all unremarkable. A tentative diagnosis of trigeminal neuritis as a complication of HL involving the CNS was made considering the clinical, neuroradiological, and laboratory findings of the patient. Therefore, the patient was treated with intravenous methylprednisolone and acyclovir for 10 days. After the treatments, her sensory disturbance was markedly improved. Brain MRI at the 3-month follow-up also demonstrated improvement of previously identified high signal intensity lesions and multifocal intracerebral artery stenoses. CONCLUSION: HL is usually a self-limiting, benign disease without complications, but rarely presents as trigeminal neuritis due to CNS involvement. Therefore, meticulous evaluation may be necessary if trigeminal neuritis or CNS involving symptoms occur after HL.

Clinical Effect of Mudan Granule on Peripheral Neuritis Caused by Chronic Renal Insufficiency.

Objective: To investigate the clinical effect of Mudan granule on peripheral neuritis caused by chronic renal insufficiency (CRI). Methods: Sixty patients with peripheral neuritis caused by CRI treated in our hospital were included from February 2018 to April 2021 in this study. The patients were arbitrarily assigned into control group and study group. The former accepted routine treatment, while the latter accepted Mudan granule treatment. The clinical efficacy, traditional Chinese medicine (TCM) clinical symptom score, nerve conduction velocity, hemorheology index, renal function index, and inflammatory factor index were compared. Results: We firstly compared the clinical efficacy: the study group was clinically cured in 22 cases, obviously effective in 5 cases, effective in 3 cases, and ineffective in 1 case, with a total effective rate of 96.67%. The control group was clinically cured in 9 cases, obviously effective in 8 cases, effective in 7 cases, and ineffective in 6 cases, with a total effective rate of 80.00%. The total effective rate of the study group was higher compared to the control group (P < 0.05). Secondly, we compared the TCM clinical symptom scores; before treatment, there exhibited no significant difference (P > 0.05); after treatment, the TCM clinical symptom scores decreased. The clinical symptom score of TCM in the study group was lower compared to the control group (P < 0.05). Compared with the control group, the nerve conduction velocity of left MCV, right MCV, left SCV, and right SCV in the study group were remarkably higher. In terms of the hemorheological indexes, the high-shear whole blood viscosity, low-shear whole blood viscosity, and plasma viscosity in the study group were lower compared with the control group (P < 0.05). Before treatment, there existed no significant difference in renal function indexes, but after treatment, the renal function indexes decreased, and the levels of serum creatinine (SCr), blood urea nitrogen (BUN), and uric acid (UA) in the study group were lower compared to the control group (P < 0.05). Finally, we compared the indexes of inflammatory factors; there existed no significant difference before treatment, but after treatment, the indexes of inflammatory factors decreased in both groups, and the levels of IL-6 and CRP in the study group were lower compared to the control group (P < 0.05). Conclusion: For peripheral neuritis caused by CRI, Mudan granule can remarkably promote the clinical symptoms of TCM and reduce the syndrome score of TCM; moreover, it can remarkably increase the nerve conduction velocity of median nerve and common peroneal nerve and reduce blood viscosity, which is worth popularizing and developing in clinic.

Dramatic secukinumab-mediated improvements in refractory leprosy-related neuritis via the modulation of T helper 1 (Th1) and T helper 17 (Th17) immune pathways.

A 39-year-old woman was diagnosed with relapsed multibacillary leprosy and refractory neuritis. Here, we describe an evident loss of therapeutic effectiveness after the third pulse of corticosteroids, which may be attributed to tachyphylaxis and the posterior modulation of interferon- γ (IFN-γ), tumor necrosis factor- α (TNF-α,) interleukin-17A (IL-17A), and IL-12/23p40 after the induction phase of secukinumab. In this case, plasma cytokine analysis showed that secukinumab induced a reduction in IL-17 concomitant with impressive clinical improvements in the patient's neural function. Interestingly, secukinumab induced reductions in cytokines related to Th1 responses and earlier stages of the Th17 response, including IL-23/12.

Ghrelin attenuates depressive-like behavior, heart failure, and neuroinflammation in postmyocardial infarction rat model.

Depression after myocardial infarction (MI) and chronic heart failure (CHF) is a common condition that is resistant to anti-depressive drugs. Ghrelin (a peptide hormone) shows dual protective effects on heart and brain. Whether ghrelin treatment attenuated depression after MI was investigated. Coronary artery occlusion was performed to induce MI and subsequent CHF in rats. Ghrelin (100 µg/kg in 0.5 ml of saline) or vehicle (0.5 ml of saline) was injected subcutaneously twice a day for 4 weeks. At week 5, all the animals underwent behavioral assessments including sucrose preference test (SPT), elevated plus maze test (EPM), and open field test (OFT). After cardiac function analysis, brain tissues were processed to determine inflammatory cytokines and microglial activations in hippocampus. Results showed that ghrelin substantially improved cardiac dysfunction, infarction size, and cardiac remodeling and modulated the release of inflammatory cytokines and the increase of Iba-1 positive microglia and glial fibrillary acidic protein-positive astrocytes in the CA1 area of hippocampus. Behavioral tests revealed that this treatment remarkably increased sucrose preference and mobile times and numbers. These findings provided evidence that peripheral ghrelin administration inhibits depression-like behavior and neuroinflammation and thus could be a new approach for the treatment of CHF-associated depression.

Dramatic secukinumab-mediated improvements in refractory leprosy-related neuritis via the modulation of T helper 1 (Th1) and T helper 17 (Th17) immune pathways

Abstract A 39-year-old woman was diagnosed with relapsed multibacillary leprosy and refractory neuritis. Here, we describe an evident loss of therapeutic effectiveness after the third pulse of corticosteroids, which may be attributed to tachyphylaxis and the posterior modulation of interferon- γ (IFN-γ), tumor necrosis factor- α (TNF-α,) interleukin-17A (IL-17A), and IL-12/23p40 after the induction phase of secukinumab. In this case, plasma cytokine analysis showed that secukinumab induced a reduction in IL-17 concomitant with impressive clinical improvements in the patient's neural function. Interestingly, secukinumab induced reductions in cytokines related to Th1 responses and earlier stages of the Th17 response, including IL-23/12.

Polyphenols from the flower of Hibiscus syriacus Linn ameliorate neuroinflammation in LPS-treated SH-SY5Y cell.

The flower of Hibiscus syriacus Linn is a well-known traditional Chinese medicine (TCM) and health food in China, which has been used to treat dysentery, vaginal discharge, and hemorrhoids. In this study, five polyphenols (compounds 1-5) and five fatty acids (compounds 6-10) were isolated from the ethanol extract of the flower of H. syriacus. The isolated compounds were characterized by spectroscopic techniques. Polyphenols, an important type of natural product, have variety of biological activities. Here, we employed LPS or H2O2-treated SH-SY5Y cell models to test the neuroprotective effect of compounds 1-10. Results found compounds 1-5 (concentration range was around 20 µM on LPS model, concentration range was around 13 µM on H2O2 model), not compounds 6-10, exhibited neuroprotective effect in LPS or H2O2-treated SH-SY5Y cell. PCR analysis showed that compounds 1-5 can effectively improve the mRNA expression of synapse-related gene and neurotrophic factors (Syp, NGF and BDNF) in LPS-treated SH-SY5Y cell. In addition, compounds 1-5 decreased the levels of ROS and MDA and increased the activities of SOD, GSH-Px and CAT in LPS-treated SH-SY5Y cell. Furthermore, compounds 1-5 inhibited neuroinflammation (TNF-α, IL-1ß and IL-6) in LPS-treated SH-SY5Y cell. In conclusion, the polyphenols in the flower of H. syriacus could be a promising candidate for preventive effect of neuroinflammation.

Intravenous Vitamin C as Ancillary Treatment for Cranial Polyneuritis and Meningitis due to Varicella Zoster Virus Reactivation.

A 65-year-old Japanese woman developed vesicular eruptions on her right ear due to varicella zoster virus (VZV) reactivation, followed by cranial polyneuritis and meningitis affecting her right cranial nerves V, VII, VIII, IX, and X. After acyclovir administration, her facial paralysis worsened. Intravenous methylprednisolone and vitamin C were administered on Day 4 post-admission. Her symptoms steadily improved, and by Day 45 she had fully recovered. Cranial polyneuritis is a rare complication of VZV reactivation, and there is no established method of treatment. This is the first report of full recovery from cranial polyneuritis using intravenous vitamin C as ancillary treatment.

Nerve ultrasound improves detection of treatment-responsive chronic inflammatory neuropathies.

OBJECTIVE: To examine the diagnostic accuracy of nerve ultrasound in a prospective cohort of consecutive patients with a clinical suspicion of chronic inflammatory neuropathies, including chronic inflammatory demyelinating polyneuropathy, Lewis-Sumner syndrome, and multifocal motor neuropathy, and to determine the added value in the detection of treatment-responsive patients. METHODS: Between February 2015 and July 2018, we included 100 consecutive incident patients with a clinical suspicion of chronic inflammatory neuropathy. All patients underwent nerve ultrasound, extensive standardized nerve conduction studies (NCS), and other relevant diagnostic investigations. We evaluated treatment response using predefined criteria. A diagnosis of chronic inflammatory neuropathy was established when NCS were abnormal (fulfilling criteria of demyelination of the European Federation of Neurological Societies/Peripheral Nerve Society) or when the degree of nerve enlargement detected by sonography was compatible with chronic inflammatory neuropathy and there was response to treatment. RESULTS: A diagnosis of chronic inflammatory neuropathy was established in 38 patients. Sensitivity and specificity of nerve ultrasound and NCS were 97.4% and 69.4% and 78.9% and 93.5%, respectively. The added value of nerve ultrasound in detection of treatment-responsive chronic inflammatory neuropathy was 21.1% compared to NCS alone. CONCLUSIONS: Nerve ultrasound and NCS are complementary techniques with superior sensitivity in the former and specificity in the latter. Addition of nerve ultrasound significantly improves the detection of chronic inflammatory neuropathies. Therefore, it deserves a prominent place in the diagnostic workup of chronic inflammatory neuropathies. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that nerve ultrasound is an accurate diagnostic tool to detect chronic inflammatory neuropathies.

Hesperetin, a Citrus Flavonoid, Attenuates LPS-Induced Neuroinflammation, Apoptosis and Memory Impairments by Modulating TLR4/NF-κB Signaling.

Glial activation and neuroinflammation play significant roles in apoptosis as well as in the development of cognitive and memory deficits. Neuroinflammation is also a critical feature in the pathogenesis of neurodegenerative disorders such as Alzheimer and Parkinson's diseases. Previously, hesperetin has been shown to be an effective antioxidant and anti-inflammatory agent. In the present study, in vivo and in vitro analyses were performed to evaluate the neuroprotective effects of hesperetin in lipopolysaccharide (LPS)-induced neuroinflammation, oxidative stress, neuronal apoptosis and memory impairments. Based on our findings, LPS treatment resulted in microglial activation and astrocytosis and elevated the expression of inflammatory mediators such as phosphorylated-Nuclear factor-κB (p-NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß) in the cortical and hippocampal regions and in BV2 cells. However, hesperetin cotreatment markedly reduced the expression of inflammatory cytokines by ameliorating Toll-like receptor-4 (TLR4)-mediated ionized calcium-binding adapter molecule 1/glial fibrillary acidic protein (Iba-1/GFAP) expression. Similarly, hesperetin attenuated LPS-induced generation of reactive oxygen species/lipid per oxidation (ROS/LPO) and improved the antioxidant protein level such as nuclear factor erythroid 2-related factor 2 (Nrf2) and Haem-oxygenase (HO-1) in the mouse brain. Additionally, hesperetin ameliorated cytotoxicity and ROS/LPO induced by LPS in HT-22 cells. Moreover, hesperetin rescued LPS-induced neuronal apoptosis by reducing the expression of phosphorylated-c-Jun N-terminal kinases (p-JNK), B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax), and Caspase-3 protein and promoting the Bcl-2 protein level. Furthermore, hesperetin enhanced synaptic integrity, cognition, and memory processes by enhancing the phosphorylated-cAMP response element binding protein (p-CREB), postsynaptic density protein-95 (PSD-95), and Syntaxin. Overall, our preclinical study suggests that hesperetin conferred neuroprotection by regulating the TLR4/NF-κB signaling pathway against the detrimental effects of LPS.

Neuritis and vinblastine-induced axonal transport disruption lead to signs of altered dorsal horn excitability.

BACKGROUND: Many patients with neuropathic pain present without signs of nerve injury on routine clinical examination. Some of these patients may have inflamed peripheral nerves (neuritis). In this study, we have examined whether neuritis causes changes within the dorsal horn that may contribute to a central pain mechanism. Comparisons have been made to a model of axonal transport disruption induced using vinblastine, since neuritis disrupts such processes. RESULTS: At the peak of cutaneous hypersensitivities, recordings from wide dynamic range neurons revealed increases in wind-up following neuritis but not vinblastine treatment. Ongoing activity from these neurons was unchanged. Vinblastine treatment caused a reduction in the responses of wide dynamic range neurons to noxious mechanical stimulation of the receptive field. The response of neurons to innocuous mechanical stimulation was also reduced in wide dynamic range neurons that were at a depth ≥550 µm following vinblastine treatment. An examination of the superficial dorsal horn revealed an increase in c-Fos-positive neurons in both groups following electrical stimulation of the sciatic nerve. The area of dorsal horn expressing substance P was also decreased following vinblastine treatment. CONCLUSION: These findings indicate that a minor nerve insult, such as neuritis, can lead to changes within the dorsal horn that are consistent with a central neuropathic pain mechanism.

Effectiveness of the retreatment of patients with multibacillary leprosy and episodes of erythema nodosum leprosum and/or persistent neuritis: a single-center experience.

BACKGROUND: Erythema nodosum leprosum may appear before, during or after treatment of leprosy and is one of the main factors for nerve damage in patients. When it occurs or continues to occur after treatment, it may indicate disease recurrence and a new treatment may be instituted again. OBJECTIVE: To evaluate the retreatment of patients with multibacillary leprosy who underwent standard treatment with multidrug therapy, but developed or continued to present reactions of erythema nodosum leprosum and/or neuritis 3-5 years after its end. METHOD: For this objective, a new treatment was performed in 29 patients with multibacillary leprosy who maintained episodes of erythema nodosum and/or neuritis 3-5 years after conventional treatment. RESULTS: In general, we observed that 27 (93.10%) had no more new episodes after a follow up period of eight months to five years. In five of these patients the reason for the retreatment was the occurrence of difficult-to-control neuritis, and that has ceased to occur in all of them. STUDY LIMITATIONS: Small number of patients.. CONCLUSION: In the cases observed, retreatment was an effective measure to prevent the occurrence of erythema nodosum leprosum and/or persistent neuritis.

Therapeutic dosage of ozone inhibits autophagy and apoptosis of nerve roots in a chemically induced radiculoneuritis rat model.

OBJECTIVE: Radiculoneuritis characterizes by the neurogenic pain along the back of patients. This study aims to investigate the therapeutic effects of ozone on radiculoneuritis and the associated mechanisms in rat models. MATERIALS AND METHODS: A chemical radiculoneuritis rat model was successfully established. The rats were divided into 3 groups, including radiculoneuritis Model rats group (Model group, n=18), Ozone therapy group (n=18), and Normal control group (n=18). Ozone was administered at a dosage of 1 mg/kg/day. The electron microscope was used to observe autophagosomes in the cytoplasm. Immunohistochemistry assay was performed to examine cleaved caspase 3 and double-labeled immunofluorescence assay was used to detect light chain 3B (LC3B) and neuronal nuclear antigen (NeuN) expression. Quantitative Real-time PCR (RT-PCR) and Western blot were employed to evaluate the expression of LC3B, Beclin 1, phosphodiesterase 2A (PDE2A), and nuclear factor-kB p65 (NF-kBp65). RESULTS: Ozone significantly decreased autophagosomes formation and inhibited autophagy of nerve root cells in radiculoneuritis rat model. Ozone significantly decreased levels of autophagosomes initiator, LC3B, compared to Model group (p<0.05). Ozone significantly decreased cleaved caspase 3 expressions and alleviated apoptosis of nerve root cells compared to that of Model group (p<0.05). According to RT-PCR and Western blot assay, ozone significantly suppressed LC3B and Beclin 1 expression compared to that of Model group (p<0.05). Ozone significantly decreased PDE2A and NF-kB p65 expression compared to that of the Model group (p<0.05). CONCLUSIONS: Therapeutic dosage of ozone inhibits autophagy by suppressing LC3B and Beclin 1 expression and reduces apoptosis by blocking NF-kB signaling pathway.

Discovery of Trifluoromethyl Glycol Carbamates as Potent and Selective Covalent Monoacylglycerol Lipase (MAGL) Inhibitors for Treatment of Neuroinflammation.

Monoacylglycerol lipase (MAGL) inhibition provides a potential treatment approach to neuroinflammation through modulation of both the endocannabinoid pathway and arachidonoyl signaling in the central nervous system (CNS). Herein we report the discovery of compound 15 (PF-06795071), a potent and selective covalent MAGL inhibitor, featuring a novel trifluoromethyl glycol leaving group that confers significant physicochemical property improvements as compared with earlier inhibitor series with more lipophilic leaving groups. The design strategy focused on identifying an optimized leaving group that delivers MAGL potency, serine hydrolase selectivity, and CNS exposure while simultaneously reducing log  D, improving solubility, and minimizing chemical lability. Compound 15 achieves excellent CNS exposure, extended 2-AG elevation effect in vivo, and decreased brain inflammatory markers in response to an inflammatory challenge.