The Use of Nitrosative Stress Molecules as Potential Diagnostic Biomarkers in Multiple Sclerosis.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) of still unclear etiology. In recent years, the search for biomarkers facilitating its diagnosis, prognosis, therapy response, and other parameters has gained increasing attention. In this regard, in a previous meta-analysis comprising 22 studies, we found that MS is associated with higher nitrite/nitrate (NOx) levels in the cerebrospinal fluid (CSF) compared to patients with non-inflammatory other neurological diseases (NIOND). However, many of the included studies did not distinguish between the different clinical subtypes of MS, included pre-treated patients, and inclusion criteria varied. As a follow-up to our meta-analysis, we therefore aimed to analyze the serum and CSF NOx levels in clinically well-defined cohorts of treatment-naïve MS patients compared to patients with somatic symptom disorder. To this end, we analyzed the serum and CSF levels of NOx in 117 patients (71 relapsing-remitting (RR) MS, 16 primary progressive (PP) MS, and 30 somatic symptom disorder). We found that RRMS and PPMS patients had higher serum NOx levels compared to somatic symptom disorder patients. This difference remained significant in the subgroup of MRZ-negative RRMS patients. In conclusion, the measurement of NOx in the serum might indeed be a valuable tool in supporting MS diagnosis.

Neuromyotonia with Central Nervous System Lesions following Quadrivalent Human Papilloma Virus Vaccination.

Neuromyotonia is a rare peripheral nerve hyperexcitability syndrome often associated with antibodies directed against contactin-associated protein-like 2 and leucine-rich, glioma inactivated 1. The quadrivalent human papilloma virus vaccine Gardasil®, first approved in 2006, is known to be a highly effective prophylaxis against papillomavirus types 6, 11, 16, and 18. Molecularly, this non-infectious recombinant vaccine is based on purified L1 proteins from the human papilloma virus capsid. Since the approval of this vaccine, several studies have investigated its safety regarding the occurrence of autoimmune conditions following application. Here, we present the first case of neuromyotonia with active Gadolinium enhancing demyelinating central nervous system lesions following vaccination with Gardasil®.

Vaccine-based clinical protection against SARS-CoV-2 infection and the humoral immune response: A 1-year follow-up study of patients with multiple sclerosis receiving ocrelizumab.

Introduction: Given the varying severity of coronavirus disease 2019 (COVID-19) and the rapid spread of Severe-Acute-Respiratory-Syndrome-Corona-Virus-2 (SARS-CoV-2), vaccine-mediated protection of particularly vulnerable individuals has gained increasing attention during the course of the pandemic. Methods: We performed a 1-year follow-up study of 51 ocrelizumab-treated patients with multiple sclerosis (OCR-pwMS) who received COVID-19 vaccination in 2021. We retrospectively identified 37 additional OCR-pwMS, 42 pwMS receiving natalizumab, 27 pwMS receiving sphingosine 1-phosphate receptor modulators, 59 pwMS without a disease-modifying therapy, and 61 controls without MS (HC). In OCR-pwMS, anti-SARS-CoV-2(S)-antibody titers were measured prior to the first and after the second, third, and fourth vaccine doses (pv2/3/4). The SARS-CoV-2-specific T cell response was analyzed pv2. SARS-CoV-2 infection status, COVID-19 disease severity, and vaccination-related adverse events were assessed in all pwMS and HC. Results: We found a pronounced and increasing anti-SARS-CoV-2(S)-antibody response after COVID-19 booster vaccinations in OCR-pwMS (pv2: 30.4%, pv3: 56.5%, and pv4 90.0% were antibody positive). More than one third of OCR-pwMS without detectable antibodies pv2 developed positive antibodies pv3. 23.5% of OCR-pwMS had a confirmed SARS-CoV-2 infection, of which 84.2% were symptomatic. Infection rates were comparable between OCR-pwMS and control groups. None of the pwMS had severe COVID-19. An attenuated humoral immune response was not associated with a higher risk of SARS-CoV-2 infection. Discussion: Additional COVID-19 vaccinations can boost the humoral immune response in OCR-pwMS and improve clinical protection against COVID-19. Vaccines effectively protect even OCR-pwMS without a detectable COVID-19 specific humoral immune response, indicating compensatory, e.g., T cell-mediated immunological mechanisms.

Nitrosative Stress Molecules in Multiple Sclerosis: A Meta-Analysis.

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system of unknown etiology. As it is still a diagnosis of exclusion, there is an urgent need for biomarkers supporting its diagnosis. Increasing evidence suggests that nitrosative stress may play a pivotal role in the pathogenesis of MS. However, previous reports supporting the role of nitrosative stress molecules as disease biomarkers are inconsistent overall. We therefore systematically analyzed the existing literature to compare the serum and cerebrospinal fluid (CSF) levels of nitrite/nitrate in MS patients with those in patients with noninflammatory other neurological diseases (NIOND) and healthy controls (HC), respectively. We searched the PubMed database and included original articles investigating nitrite/nitrate levels in MS patients and NIOND patients or HC based on predefined selection criteria. Effect sizes were estimated by the standardized mean difference using a random effects model. Our results suggest that MS is associated with higher nitrite/nitrate levels within the CSF compared with patients with NIOND (SMD of 1.51; 95% CI: 0.72, 2.30; p = 0.0008). Likewise, nitrite/nitrate in the CSF of MS patients trends towards increased levels compared with those of HC but does not reach statistical significance (SMD of 3.35; 95% CI: -0.48, 7.19; p = 0.07). Measurement of nitrite/nitrate in the CSF might be a valuable tool facilitating the differentiation of MS and NIOND. Further studies with more homogeneous study criteria are needed to corroborate this hypothesis.

Case Report: Persisting Lymphopenia During Neuropsychiatric Tumefactive Multiple Sclerosis Rebound Upon Fingolimod Withdrawal.

Fingolimod (FTY) is a disease modifying therapy for relapsing remitting multiple sclerosis (RRMS) which can lead to severe lymphopenia requiring therapy discontinuation in order to avoid adverse events. However, this can result in severe disease reactivation occasionally presenting with tumefactive demyelinating lesions (TDLs). TDLs, which are thought to originate from a massive re-entry of activated lymphocytes into the central nervous system, are larger than 2 cm in diameter and may feature mass effect, perifocal edema, and gadolinium enhancement. In these cases, it can be challenging to exclude important differential diagnoses for TDLs such as progressive multifocal leukoencephalopathy (PML) or other opportunistic infections. Here, we present the case of a 26-year-old female patient who suffered a massive rebound with TDLs following FTY discontinuation with primarily neuropsychiatric symptoms despite persisting lymphopenia. Two cycles of seven plasmaphereses each were necessary to achieve remission and ocrelizumab was used for long-term stabilization.

Case Report: Successful Stabilization of Marburg Variant Multiple Sclerosis With Ocrelizumab Following High-Dose Cyclophosphamide Rescue.

The Marburg variant of multiple sclerosis (Marburg MS) is the most aggressive form of MS, often leading to death soon after onset. Here we describe the case of a 26-year-old Marburg MS patient presenting with severe neurological deficits requiring intensive care. In spite of more than 100 gadolinium-enhancing MRI lesions, the patient recovered almost completely upon high-dose cyclophosphamide (HiCy) rescue treatment (four consecutive days with 50 mg/kg/day, cumulative absolute dose of 14 g). Following the acute treatment, her disease was stabilized by B cell depletion using ocrelizumab. Clinical amelioration was reflected by a decrease of MRI activity and a marked decline of serum neurofilament light chain levels. HiCy rescue treatment followed by ocrelizumab as a maintenance therapy prevented permanent disability and achieved an almost complete clinical and drastic radiological improvement in this Marburg MS patient.

Neurological manifestations of severe acute respiratory syndrome coronavirus 2-a controversy 'gone viral'.

Severe acute respiratory syndrome coronavirus 2 first appeared in December 2019 in Wuhan, China, and developed into a worldwide pandemic within the following 3 months causing severe bilateral pneumonia (coronavirus disease 2019) with in part fatal outcomes. After first experiences and tentative strategies to face this new disease, several cases were published describing severe acute respiratory syndrome coronavirus 2 infection related to the onset of neurological complaints and diseases such as, for instance, anosmia, stroke or meningoencephalitis. Of note, there is still a controversy about whether or not there is a causative relation between severe acute respiratory syndrome coronavirus 2 and these neurological conditions. Other concerns, however, seem to be relevant as well. This includes not only the reluctance of patients with acute neurological complaints to report to the emergency department for fear of contracting severe acute respiratory syndrome coronavirus 2 but also the ethical and practical implications for neurology patients in everyday clinical routine. This paper aims to provide an overview of the currently available evidence for the occurrence of severe acute respiratory syndrome coronavirus 2 in the central and peripheral nervous system and the neurological diseases potentially involving this virus.

Case Report: A Case of Severe Clinical Deterioration in a Patient With Multiple Sclerosis.

Tumefactive multiple sclerosis (MS) is a rare variant of MS that may lead to a rapidly progressive clinical deterioration requiring a multidisciplinary diagnostic workup. Our report describes the diagnostic and therapeutic approach of a rare and extremely severe course of MS. A 51-year-old man with an 8-year history of relapsing-remitting MS (RRMS) was admitted with a subacute progressive left lower limb weakness and deterioration of walking ability. After extensive investigations including repeated MRI, microbiological, serological, cerebrospinal fluid (CSF) studies, and finally brain biopsy, the diagnosis of a tumefactive MS lesion was confirmed. Despite repeated intravenous (IV) steroids as well as plasma exchanges and IV foscarnet and ganciclovir owing to low copy numbers of human herpesvirus 6 (HHV-6) DNA in polymerase chain reaction (PCR) analysis, the patient did not recover. The clinical presentation of tumefactive MS is rare and variable. Brain biopsy for histopathological workup should be considered in immunocompromised patients with rapidly progressive clinical deterioration with brain lesions of uncertain cause.

The Molecular Basis for Remyelination Failure in Multiple Sclerosis.

Myelin sheaths in the central nervous system (CNS) insulate axons and thereby allow saltatory nerve conduction, which is a prerequisite for complex brain function. Multiple sclerosis (MS), the most common inflammatory autoimmune disease of the CNS, leads to the destruction of myelin sheaths and the myelin-producing oligodendrocytes, thus leaving behind demyelinated axons prone to injury and degeneration. Clinically, this process manifests itself in significant neurological symptoms and disability. Resident oligodendroglial precursor cells (OPCs) and neural stem cells (NSCs) are present in the adult brain, and can differentiate into mature oligodendrocytes which then remyelinate the demyelinated axons. However, for multiple reasons, in MS the regenerative capacity of these cell populations diminishes significantly over time, ultimately leading to neurodegeneration, which currently remains untreatable. In addition, microglial cells, the resident innate immune cells of the CNS, can contribute further to inflammatory and degenerative axonal damage. Here, we review the molecular factors contributing to remyelination failure in MS by inhibiting OPC and NSC differentiation or modulating microglial behavior.

Drug Treatment of Clinically Isolated Syndrome.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that leads to inflammation, demyelination and ultimately axonal degeneration. In most cases, it is preceded by its precursor, clinically isolated syndrome (CIS) with conversion rates to clinically definite MS (CDMS) of roughly 20-75%. Neurologists are therefore faced with the challenge of initiating a disease-modifying therapy (DMT) as early as possible to favorably influence the course of the disease. During the past 20 years, a multitude of drugs have been incorporated into our therapeutic armamentarium for MS and CIS. Choosing the right drug for an individual patient is complex and should be based not only on the drug's overall efficacy to prevent disease progression but also its specific adverse reaction profile, the severity of individual disease courses and, finally, patient compliance in order to adequately weigh associated risks and benefits. Here, we review the available data on the efficacy, safety and tolerability of DMTs tested for CIS and discuss their value regarding a delay of progression to CDMS.

Managing Risks with Immune Therapies in Multiple Sclerosis.

Since the introduction of the interferons in the 1990s, a multitude of different immunomodulatory and immunosuppressant disease-modifying therapies for multiple sclerosis (MS) have been developed. They have all shown positive effects on clinical endpoints such as relapse rate and disease progression and are a heterogeneous group of therapeutics comprising recombinant pegylated and non-pegylated interferon-ß variants, peptide combinations, monoclonal antibodies, and small molecules. However, they have relevant side effect profiles, which necessitate thorough monitoring and straightforward patient education. In individual cases, side effects can be severe and potentially life-threatening, which is why knowledge about (neurological and non-neurological) adverse drug reactions is essential for prescribing neurologists as well as general practitioners. This paper aims to provide an overview of currently available MS therapies, their modes of action and safety profiles, and the necessary therapy monitoring.

Rescuing the negative impact of human endogenous retrovirus envelope protein on oligodendroglial differentiation and myelination.

Remyelination in the adult CNS depends on activation, differentiation, and functional integration of resident oligodendroglial precursor cells (OPCs) and constitutes the only spontaneous neuroregenerative process able to compensate for functional deficits upon loss of oligodendrocytes and myelin sheaths as it is observed in multiple sclerosis. The proteins encoded by p57kip2- and by human endogenous retrovirus type W (pHERV-W) envelope genes were previously identified as negative regulators of OPC maturation. We here focused on the activity of the ENV protein and investigated how it can be neutralized for an improved myelin repair. We could demonstrate that myelination in vitro is severely affected by this protein but that application of an anti-ENV neutralizing antibody, currently investigated in clinical trials, can rescue the generation of internodes. We then compared p57kip2 and ENV dependent inhibitory mechanisms and found that a dominant negative version of the p57kip2 protein can equally save OPCs from myelination failure in response to ENV-mediated TLR4 activation. Additional experiments addressing p57kip2's underlying mode of action revealed a direct interaction with ATP6v1d, a central component of a vascular ATPase. Its pharmacological blocking was then shown to exert an analogous myelination rescue effect in presence of the ENV protein. Therefore, our study provides mechanistic insights into oligodendroglial inhibition processes and presents three different means to counteract the anti-myelination effect of the ENV protein. These observations are therefore of interest in light of understanding the complexity of the numerous oligodendroglial inhibitors and might promote the establishment of novel regenerative therapies.

An unmet clinical need: roads to remyelination in MS.

BACKGROUND: In the central nervous system (CNS) myelin sheaths stabilize, protect, and electrically insulate axons. However, in demyelinating autoimmune CNS diseases such as multiple sclerosis (MS) these sheaths are destroyed which ultimately leads to neurodegeneration. The currently available immunomodulatory drugs for MS effectively control the (auto)inflammatory facets of the disease but are unable to regenerate myelin by stimulating remyelination via oligodendroglial precursor cells (OPCs). Accordingly, there is broad consensus that the implementation of new regenerative approaches constitutes the prime goal for future MS pharmacotherapy. MAIN TEXT: Of note, recent years have seen several promising clinical studies investigating the potential of substances and monoclonal antibodies such as, for instance, clemastine, opicinumab, biotin, simvastatin, quetiapin and anti-GNbAC1. However, beyond these agents which have often been re-purposed from other medical indications there is a multitude of further molecules influencing OPC homeostasis. Here, we therefore discuss these possibly beneficial regulators of OPC differentiation and assess their potential as new pharmacological targets for myelin repair in MS. CONCLUSION: Remyelination remains the most important therapeutic treatment goal in MS in order to improve clinical deficits and to avert neurodegeneration. The promising molecules presented in this review have the potential to promote remyelination and therefore warrant further translational and clinical research.

Aerobic Aliphatic Hydroxylation Reactions by Copper Complexes: A Simple Clip-and-Cleave Concept.

A simple imine clip-and-cleave concept has been developed for the selective hydroxylation of non-activated CH bonds in aliphatic aldehydes with dioxygen through a copper complex. The synthetic protocol involves reaction of a substrate aldehyde with N,N-diethyl-ethylendiamine to give the corresponding imine, which is used as a bidentate donor ligand forming a copper(I) complex with [Cu(CH3 CN)4 ][CF3 SO3 ]. After exposure of the reaction mixture to dioxygen acidic cleavage and aqueous workup liberates the corresponding ß-hydroxylated aldehyde. The concept for the hydroxylation of trimethylacetaldehyde as well as adamantane and diamantane 1-carbaldehydes was investigated and the corresponding ß-hydroxy aldehydes were obtained with high selectivities. The results of low temperature stopped-flow measurements indicate the formation of a bis(µ-oxido)dicopper complex as reactive intermediate. According to density functional theory (DFT, RI-BLYP-D3/def2-TZVP(SDD)/ COSMO(CH2 Cl2 )//RI-PBE-D3/def2-TZVP(SDD)) computations CH bonds suitably predisposed to the [Cu2 O2 ]2+ core undergo hydroxylation in a concerted step with particularly low activation barriers, which explains the experimentally observed regioselectivities.

Dinitrogen Splitting Coupled to Protonation.

The coupling of electron- and proton-transfer steps provides a general concept to control the driving force of redox reactions. N2 splitting of a molybdenum dinitrogen complex into nitrides coupled to a reaction with Brønsted acid is reported. Remarkably, our spectroscopic, kinetic, and computational mechanistic analysis attributes N-N bond cleavage to protonation in the periphery of an amide pincer ligands rather than the {Mo-N2 -Mo} core. The strong effect on electronic structure and ultimately the thermochemistry and kinetic barrier of N-N bond cleavage is an unusual case of a proton-coupled metal-to-ligand charge transfer process, highlighting the use of proton-responsive ligands for nitrogen fixation.

Copper-Mediated Selective Hydroxylation of a Non-activated C-H Bond in Steroids: A DFT Study of Schönecker's Reaction.

The regio- and stereoselective copper-mediated hydroxylation of a non-activated aliphatic C-H bond in steroids by dioxygen, initially reported by Schönecker et al. (Angew. Chem. Int. Ed. 2003, 42, 3240-3244), has recently evolved into a valuable synthetic tool. In the present work, a detailed mechanistic density functional theory (DFT) study addressing the origin of the remarkable selectivity of Schönecker's reaction is reported. The applied BLYP-D3/def2-TZVP(SDD) level of DFT is benchmarked against experimental and coupled-cluster reference data. The resulting mechanistic scenario involves formation of a bis-µ-oxo dicopper complex as key intermediate. In this complex three C-H bonds of the pendant steroid ligand are predisposed towards intramolecular activation by the bis-µ-oxo dicopper core. The lowest activation barrier (12.0 kcal mol-1 ) is computed for ß-hydroxylation at the C12 position, in agreement with the experimental observations. Natural bond orbital (NBO) analysis reveals stabilizing orbital interactions that favor the ß-hydroxylation pathway over competing reaction channels.

Oxygen Reduction with a Bifunctional Iridium Dihydride Complex.

The iridium dihydride [Ir(H)2 (HPNP)](+) (PNP=N(CH2 CH2 PtBu2 )2 ) reacts with O2 to give the unusual, square-planar iridium(III) hydroxide [Ir(OH)(PNP)](+) and water. Regeneration of the dihydride with H2 closes a quasi-catalytic synthetic oxygen-reduction reaction (ORR) cycle that can be run several times. Experimental and computational examinations are in agreement with an oxygenation mechanism via rate-limiting O2 coordination followed by H-transfer at a single metal site, facilitated by the cooperating pincer ligand. Hence, the four electrons required for the ORR are stored within the two covalent MH bonds of a mononuclear metal complex.

The neutralizing antibody GNbAC1 abrogates HERV-W envelope protein-mediated oligodendroglial maturation blockade.

BACKGROUND: The envelope protein (ENV) of the human endogenous retrovirus type W is implicated in inflammatory reactions in multiple sclerosis (MS) but also interferes with oligodendroglial maturation. A neutralizing antibody GNbAC1 has been developed and successfully been tested in clinical trials. OBJECTIVES AND METHODS: We stimulated primary oligodendroglial cells with ENV upon preincubation with GNbAC1 and assessed for nitrosative stress and myelin expression. RESULTS: Neutralization of ENV by GNbAC1 reduces its ability to induce stress reactions resulting in a rescue of myelin expression. CONCLUSIONS: Beyond immune cell modulation, this monoclonal antibody may therefore help to overcome the oligodendroglial differentiation blockade in MS.

A novel concept for the synthesis of multiply doped gold clusters [(M@Au(n)M'(m))L(k)](q+).

Heterometal-doped gold clusters are poorly accessible through wet-chemical approaches and main-group-metal- or early-transition-metal-doped gold clusters are rare. Compounds [M(AuPMe3 )11 (AuCl)](3+) (M=Pt, Pd, Ni) (1-3), [Ni(AuPPh3 )(8-2n) (AuCl)3 (AlCp*)n ] (n=1, 2) (4, 5), and [Mo(AuPMe3 )8 (GaCl2 )3 (GaCl)](+) (6) were selectively obtained by the transmetalation of [M(M'Cp*)n ] (M=Mo, E=Ga, n=6; M=Pt, Pd, Ni, M'=Ga, Al, n=4) with [ClAuPR3 ] (R=Me, Ph) and characterized by single-crystal X-ray diffraction and ESI mass spectrometry. DFT calculations were used to analyze the bonding situation. The transmetalation proved to be a powerful tool for the synthesis of heterometal-doped gold clusters with a design rule based on the 18 valence electron count for the central metal atom M and in agreement with the unified superatom concept based on the jellium model.

Human endogenous retrovirus type W envelope protein inhibits oligodendroglial precursor cell differentiation.

OBJECTIVE: Differentiation of oligodendroglial precursor cells is crucial for central nervous system remyelination and is influenced by both extrinsic and intrinsic factors. Recent studies showed that human endogenous retrovirus type W (HERV-W) contributes significantly to brain damage. In particular, its envelope protein ENV can mediate injury to specific cell types of the brain and immune system. Here, we investigated whether ENV protein affects oligodendroglial differentiation. METHODS: Immunostaining and gene expression analyses were performed to establish the expression and regulation of the known ENV receptor, Toll-like receptor 4 (TLR4), on oligodendroglial precursor cells in human brain tissue and in culture. Cultured primary oligodendroglial precursor cells were stimulated with ENV protein to determine the effects of this ligand/receptor interaction. RESULTS: We demonstrated that the ENV protein is present in close proximity to TLR4-expressing oligodendroglial precursor cells adjacent to multiple sclerosis lesions. Human and rat oligodendroglial precursor cells expressed TLR4, and the ENV-mediated activation of TLR4 led to the induction of proinflammatory cytokines and inducible nitric oxide synthase as well as the formation of nitrotyrosine groups and a subsequent reduction in myelin protein expression. INTERPRETATION: Our findings suggest that ENV-mediated induction of nitrosative stress via activation of TLR4 results in an overall reduction of the oligodendroglial differentiation capacity, thereby contributing to remyelination failure. Therefore, pharmacological or antibody-mediated inhibition of ENV may prevent the blockade of myelin repair in the diseased or injured central nervous system.