Current symptomatology in multiple sclerosis and neuromyelitis optica

The Kappa Opioid Receptor: A Promising Therapeutic Target for Multiple Pathologies

Kappa-opioid receptors (KOR) are widely expressed throughout the central nervous system, where they modulate a range of physiological processes depending on their location, including stress, mood, reward, pain, inflammation, and remyelination. However, clinical use of KOR agonists is limited by adverse effects such as dysphoria, aversion, and sedation. Within the drug-development field KOR agonists have been extensively investigated for the treatment of many centrally mediated nociceptive disorders including pruritis and pain. KOR agonists are potential alternatives to mu-opioid receptor (MOR) agonists for the treatment of pain due to their anti-nociceptive effects, lack of abuse potential, and reduced respiratory depressive effects, however, dysphoric side-effects have limited their widespread clinical use. Other diseases for which KOR agonists hold promising therapeutic potential include pruritis, multiple sclerosis, Alzheimer’s disease, inflammatory diseases, gastrointestinal diseases, cancer, and ischemia. This review highlights recent drug-development efforts targeting KOR, including the development of G-protein–biased ligands, mixed opioid agonists, and peripherally restricted ligands to reduce side-effects. We also highlight the current KOR agonists that are in preclinical development or undergoing clinical trials.

Impact of Neuromyelitis Optica Spectrum Disorder on Quality of Life from the Patients' Perspective: An Observational Cross-Sectional Study

Introduction

Neuromyelitis optica spectrum disorder (NMOSD) is associated with a reduced health-related quality of life (HRQoL). The purpose of this study was to describe the impact of NMOSD on HRQoL from the patients’ perspective and its relationship with other disease factors.

Methods

An observational, cross-sectional study was conducted at 13 neuroimmunology clinics in Spain. Patients with NMOSD diagnosis (2015 Wingerchuk criteria) were included. The 29-item Multiple Sclerosis Impact Scale (MSIS-29) was used to assess the HRQoL. Different questionnaires were used to measure symptom severity, stigma, mood disorders, pain, fatigue, and difficulties in the workplace. Factors that impact HRQoL were identified by Spearman’s correlation and multivariate linear regression analysis.

Results

Seventy-one patients were included (mean age 47.4 ± 14.9 years, 80.3% female, mean time since disease onset 9.9 ± 8.1 years). The median Expanded Disability Status Scale score was 3.0 (1.5–4.5). The mean (± SD) physical and psychological MSIS-29 sub-scores were 41.9 ± 16.8 and 20.9 ± 8.3, respectively. Fatigue and body pain were the most prevalent symptoms. Depressive symptoms were found in 44.3% (n = 31) of patients. The physical MSIS-29 dimension showed the highest correlation with symptom severity (ρ = 0.85584, p < 0.0001), whereas the highest correlations for psychological MSIS-29 dimension were pain, MSIS-29 physical dimension, and depression (ρ = 0.76487, 0.72779, 0.71380; p < 0.0001, respectively). Pain was a predictor of both dimensions of MSIS-29.

Conclusion

Fatigue, pain, and depressive symptoms are frequent problems among patients with NMOSD, impacting on their quality of life. Assessment of patient-oriented outcomes may be useful to achieve a holistic approach, allowing early specific interventions.

Cytokine-chemokine and cognitive profile of multiple sclerosis patients with predominant optic nerve and spinal cord involvement

Context/Objective: Clinical disease activity in multiple sclerosis (MS) may manifest as predominant involvement of optic nerves and spinal cord, as exemplified by opticospinal multiple sclerosis (OSMS) often encountered in Asian countries. Our aim was to compare the clinical features, neuropsychological profile and cytokine/chemokine levels of patients with conventional MS (CMS) and MS presenting predominantly with spinal cord and optic nerve attacks (MS-SCON).Design: Cross-sectional study.Setting: MS Outpatient Clinic.Participants: Fourteen MS-SCON patients, 20 CMS patients without myelitis and optic neuritis attacks and 21 healthy individuals.Outcome measures: IL-8, IL-10, IFN-γ, IL-17 and TNF-α levels were measured by multiplex assay and CXCL2 and CXCL5 levels were measured by ELISA. A panel of neuropsychological tests, Beck depression inventory, 9-hole peg and timed 25-foot walk tests were employed.Results: CMS and MS-SCON patients showed similar clinical features. Both CMS and MS-SCON patients displayed reduced IL-8 and CXCL2 and increased TNF-α levels, while IL-10 and CXCL5 levels were identical among all groups.Conclusion: Neuropsychological and motor function test performances of CMS and MS-SCON patients were highly comparable. CMS and MS-SCON present with similar clinical, neuropsychological and immunological features. Therefore, optic nerve and spinal cord-dominant form of MS does not necessarily establish a distinct entity in our region. Cognitive networks of the central nervous system may be damaged during the disease course of MS, despite the absence of cerebral or cerebellar clinical attacks.

Seizure incidence among neuromyelitis optica spectrum disorder patients

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSDs) are a group of neuroinflammatory diseases, which mainly affect the optic nerve and spinal cord. NMOSD is an astrocytic channelopathy involving the aquaporin-4 (AQP4) water channels in the central nervous system. Patients can present with seizure attacks as a first manifestation or relapse. However, compared with multiple sclerosis (MS) or myelin oligodendrocyte glycoprotein encephalomyelitis (MOG-EM), seizure attacks are less frequent in NMOSD.

METHODS

In this study, we aimed to find out the incidence of seizure attacks during the disease course of 137 NMOSD patients who were registered in our centre from January 2011 till January 2020. Furthermore, we reviewed the literature for NMOSD cases with seizure attacks during their follow-up, in order to investigate the reason for this low incidence of seizures.

RESULTS

Only one of our patients (0.72%) experienced an episode of generalised tonic-clonic seizure during his follow-up.

CONCLUSION

Reviewing the literature revealed that although seizures are rare in NMOSD, AQP4 disruption possibly increases the risk of seizure attacks. We therefore concluded that the role of AQP4 in seizures is controversial and needs more investigation.

Pain in NMOSD and MOGAD: A Systematic Literature Review of Pathophysiology, Symptoms, and Current Treatment Strategies

Neuromyelitis optica spectrum disorders (NMOSDs) and myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) are autoimmune inflammatory disorders of the central nervous system (CNS). Pain is highly prevalent and debilitating in NMOSD and MOGAD with a severe impact on quality of life, and there is a critical need for further studies to successfully treat and manage pain in these rare disorders. In NMOSD, pain has a prevalence of over 80%, and pain syndromes include neuropathic, nociceptive, and mixed pain, which can emerge in acute relapse or become chronic during the disease course. The impact of pain in MOGAD has only recently received increased attention, with an estimated prevalence of over 70%. These patients typically experience not only severe headache, retrobulbar pain, and/or pain on eye movement in optic neuritis but also neuropathic and nociceptive pain. Given the high relevance of pain in MOGAD and NMOSD, this article provides a systematic review of the current literature pertaining to pain in both disorders, focusing on the etiology of their respective pain syndromes and their pathophysiological background. Acknowledging the challenge and complexity of diagnosing pain, we also provide a mechanism-based classification of NMOSD- and MOGAD-related pain syndromes and summarize current treatment strategies.

Characterization of pain syndromes in patients with neuromyelitis optica

BACKGROUND

Pain is common and refractory in spinal cord injury (SCI). Currently, most studies evaluated pain in male-predominant traumatic-SCI. Also, concomitant secondary pain syndromes and its temporal evolution were seldom reported.

METHODS

We aimed to prospectively describe the main and secondary pain and its associated factors in inflammatory-SCI evaluating neuromyelitis optica (NMO) patients. In-remission NMO patients underwent neurological, imaging and autoantibody evaluations. Questionnaires detailing main and secondary pains, functional state, mood, catastrophizing, quality of life (QoL) and "non-motor symptoms" were used at two time points.

RESULTS

Pain was present in 53 (73.6%) of the 72 patients included. At-level neuropathic pain was the most common main pain syndrome, affecting 32 subjects (60.4% of those with pain). Over 70% (n = 38) of this cohort reported two pain syndromes. Those without pain were significantly younger (26.1 ± 12.7 y.o. in those without pain and 40.1 ± 12.5, 37.2 ± 11.4 y.o. in those whose main pain was neuropathic and non-neuropathic, respectively, p = .001), and no differences in the inflammatory status were observed between groups. On follow-up, one-fifth (n = 11) had a different main pain syndrome from the first visit. Pain impacted QoL as much as disability and motor strength.

CONCLUSION

Pain is a prevalent and disabling non-motor symptom in NMO-SCI. Most patients experience more than one pain syndrome which can change in time even in the absence of clinical relapse. Age of the inflammatory-SCI was a major determinant of pain. Acknowledging temporal changes and multiplicity of pain syndromes in NMO-SCI may give insights into more precise designs of clinical trials and general management of pain in SCI.

SIGNIFICANCE

In this longitudinal study with NMO-related SCI, pain affected almost three-quarters of patients with NMO. Over 70% have more than one pain syndrome and at-level neuropathic pain is the most common type of pain syndrome. Patients without pain were significantly younger but had the same burden of inflammatory lesions than those with pain. During follow-up, up to one fifth of patients presented with changes in the main pain syndromes, which can occur even in the absence of clinical activity of the inflammatory disease. In this cohort, Pain affected quality of life as much as disability or motor strength.

What do we currently know about the clinically isolated syndrome suggestive of multiple sclerosis? An update

Multiple sclerosis (MS) is a chronic, demyelinating, not fully understood disease of the central nervous system. The first demyelinating clinical episode is called clinically isolated syndrome (CIS) suggestive of MS. Although the most common manifestations of CIS are long tracts dysfunction and unilateral optic neuritis, it can also include isolated brainstem syndromes, cerebellar involvement, and polysymptomatic clinical image. Recently, the frequency of CIS diagnosis has decreased due to the more sensitive and less specific 2017 McDonald criteria compared with the revisions from 2010. Not all patients with CIS develop MS. The risk of conversion can be estimated based on many predictive factors including epidemiological, ethnical, clinical, biochemical, radiological, immunogenetic, and other markers. The management of CIS is nowadays widely discussed among clinicians and neuroscientists. To date, interferons, glatiramer acetate, teriflunomide, cladribine, and some other agents have been evaluated in randomized, placebo-controlled, double-blind studies relying on large groups of patients with the first demyelinating event. All of these drugs were shown to have beneficial effects in patients with CIS and might be used routinely in the future. The goal of this article is to explore the most relevant topics regarding CIS as well as to provide the most recent information in the field. The review presents CIS definition, classification, clinical image, predictive factors, and management. What is more, this is one of very few reviews summarizing the topic in the light of the 2017 McDonald criteria.

Difference in fatigue and pain between neuromyelitis optica spectrum disorder and multiple sclerosis

Objective

To investigate the difference of fatigue and pain in patients with neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS).

Methods

Data from the Modified Fatigue Impact Scale (MFIS) and Pain Effects Scale (PES) were compared between 51 NMOSD and 85 MS patients. Each score was compared in each disease group with or without clinical abnormalities. Since almost no MS patients are without brain magnetic resonance imaging abnormalities, volumetry analysis by the Lesion Segmentation Tool and statistical parametric mapping 12 were added to obtain total lesion volume and intracranial volume in MS patients, and the correlations between total lesion volume/intracranial volume and each score were investigated.

Results

Compared to the MS group, the NMOSD group showed a higher PES score (median, 15.0 vs. 7.0, P = 0.045), no difference in MFIS, and an increased percentage of patients with extended spinal cord lesions (58.8% vs. 8.2%, P < 0.001). Moreover, NMOSD and MS patients with extended spinal cord lesions tended to demonstrate higher PES scores than those without. A positive correlation between MFIS and PES were found in patients with NMOSD and MS. On the other hand, MS patients showed a higher percentage of brain abnormalities (80.4% vs. 97.6%, P = 0.001) and a positive correlation between total lesion volume/intracranial volume and MFIS (Spearman’s ρ = 0.50, P = 0.033).

Conclusions

The origin of fatigue may be associated with spinal cord lesions causing pain in NMOSD patients, but with brain lesions in MS patients.

Multiple sclerosis - the remarkable story of a baffling disease

Multiple sclerosis has always been an enigma to its sufferers, their families, medical investigators, and clinicians. For many centuries, there have been attempts to understand its causes and nature, and to discover treatment methods. In the Middle Ages, the disease was claimed to be sent directly from God. A significant development in exploring multiple sclerosis took place in the 19th century, when Jean-Martin Charcot and his colleagues distinguished the disease, precisely described its symptoms, attempted to explain its pathophysiology, and introduced the first methods of symptomatic treatment. The 20th century was a period of discovery and development of diagnostic techniques, such as cerebrospinal fluid analysis, evoked potentials, and magnetic resonance imaging as well as an era of introducing steroid therapy for acute treatment. Currently, the dynamic development of disease modifying therapy and neuroimaging can be observed. The paper aims to delve into the remarkable history of multiple sclerosis by focusing on the earliest case reports and discovery of the disease and exploring its nature, diagnostic methods, and treatment.

Sexual dysfunction in patients with neuromyelitis optica spectrum disorder

BACKGROUND

Sexual dysfunction (SD) is a common but poorly understood symptom in patients with neuromyelitis optica spectrum disorder (NMOSD). The study was designed to compare SD between NMOSD patients and healthy controls (HCs), and to investigate factors that influenced SD in NMOSD patients.

METHODS

The study enrolled 102 sexually active NMOSD patients and 110 HCs. SD was investigated with the Female Sexual Function Inventory (FSFI), the abridged International Index of Erectile Function-5 (IIEF-5) and the Chinese Index of Premature Ejaculation-5 (CIPE-5). Disability, lower urinary tract dysfunction (LUTD), fatigue, depression and anxiety were also evaluated.

RESULTS

The prevalence of SD, including female sexual dysfunction (FSD), erectile dysfunction (ED), and premature ejaculation (PE), was significantly higher in NMOSD patients than in HCs (P < .01). The FSFI, IIEF-5 and CIPE-5 scores were all significantly lower in NMOSD patients than in HCs (P < .01). Correlation analysis showed that SD was strongly correlated with age, age at onset, disability, LUTD, fatigue, depression and anxiety (P < .05). Regression analysis further revealed that age at onset (OR = 1.057, P = .036), disability (OR = 1.591, P = .011), and depression (OR = 1.111, P = .041) were independent predictors of FSD in NMOSD patients.

CONCLUSIONS

This study provided evidence that SD is a common problem in NMOSD patients and that age at onset, disability, and depression are independent predictors of FSD. More attention should be paid to SD in patients with NMOSD.

Impairment of frequency-specific responses associated with altered electrical activity patterns in auditory thalamus following focal and general demyelination

Multiple sclerosis is characterized by intermingled episodes of de- and remyelination and the occurrence of white- and grey-matter damage. To mimic the randomly distributed pathophysiological brain lesions observed in MS, we assessed the impact of focal white and grey matter demyelination on thalamic function by directing targeted lysolecithin-induced lesions to the capsula interna (CI), the auditory cortex (A1), or the ventral medial geniculate nucleus (vMGN) in mice. Pathophysiological consequences were compared with those of cuprizone treatment at different stages of demyelination and remyelination. Combining single unit recordings and auditory stimulation in freely behaving mice revealed changes in auditory response profile and electrical activity pattern in the thalamus, depending on the region of the initial insult and the state of remyelination. Cuprizone-induced general demyelination significantly diminished vMGN neuronal activity and frequency-specific responses. Targeted lysolecithin-induced lesions directed either to A1 or to vMGN revealed a permanent impairment of frequency-specific responses, an increase in latency of auditory responses and a reduction in occurrence of burst firing in vMGN neurons. These findings indicate that demyelination of grey matter areas in the thalamocortical system permanently affects vMGN frequency specificity and the prevalence of bursting in the auditory thalamus.

Validation of the Modified Fatigue Impact Scale and the relationships among fatigue, pain and serum interleukin-6 levels in patients with neuromyelitis optica spectrum disorder

Fatigue and pain are disabling symptoms in patients with neuromyelitis optica spectrum disorder (NMOSD). The Modified Fatigue Impact Scale (MFIS) has not yet been validated in patients with NMOSD, and anti-interleukin-6 (IL-6) receptor antibody was reported to decrease pain and fatigue in patients with NMOSD. The aim of this study was to validate MFIS and to investigate the relationships among fatigue, pain and serum IL-6 levels in patients with NMOSD. MFIS and the Multidimensional Fatigue Inventory (MFI), an established scale for fatigue, were administered to patients with NMOSD and age- and sex-matched healthy controls (HCs). The Pain Effects Scale score and serum IL-6 levels were also measured in patients with NMOSD. Correlations among clinical characteristics, laboratory data and each score were investigated. To validate MFIS in patients with NMOSD, MFIS was administered twice within 4days from the first administration. Fifty-one patients answered the first MFIS, and 26 patients answered the second MFIS. There was no difference between the first and second MFIS scores. Patients with NMOSD had higher MFIS and MFI scores than HCs. No correlations were observed between serum IL-6 levels and either score. MFIS was validated in patients with NMOSD. Serum IL-6 levels may not be involved in the pathogenesis of fatigue and pain in patients with NMOSD.

The quality of cortical network function recovery depends on localization and degree of axonal demyelination

Myelin loss is a severe pathological hallmark common to a number of neurodegenerative diseases, including multiple sclerosis (MS). Demyelination in the central nervous system appears in the form of lesions affecting both white and gray matter structures. The functional consequences of demyelination on neuronal network and brain function are not well understood. Current therapeutic strategies for ameliorating the course of such diseases usually focus on promoting remyelination, but the effectiveness of these approaches strongly depends on the timing in relation to the disease state. In this study, we sought to characterize the time course of sensory and behavioral alterations induced by de- and remyelination to establish a rational for the use of remyelination strategies. By taking advantage of animal models of general and focal demyelination, we tested the consequences of myelin loss on the functionality of the auditory thalamocortical system: a well-studied neuronal network consisting of both white and gray matter regions. We found that general demyelination was associated with a permanent loss of the tonotopic cortical organization in vivo, and the inability to induce tone-frequency-dependent conditioned behaviors, a status persisting after remyelination. Targeted, focal lysolecithin-induced lesions in the white matter fiber tract, but not in the gray matter regions of cortex, were fully reversible at the morphological, functional and behavioral level. These findings indicate that remyelination of white and gray matter lesions have a different functional regeneration potential, with the white matter being able to regain full functionality while cortical gray matter lesions suffer from permanently altered network function. Therefore therapeutic interventions aiming for remyelination have to consider both region- and time-dependent strategies.

Factors that impact health-related quality of life in neuromyelitis optica spectrum disorder: anxiety, disability, fatigue and depression

AIMS

Neuromyelitis optica spectrum disorder (NMOSD) is associated with reduced health-related quality of life (HRQOL). This study aimed to investigate factors that impact HRQOL in NMOSD.

METHODS

A series of questionnaires were completed by 73 patients to assess the relationships between HRQOL and fatigue, depression, anxiety and sleep disorder. We also evaluated the contributions of clinical characteristics to HRQOL. Correlation and regression analysis were conducted to identify factors that negatively impact HRQOL in NMOSD.

RESULTS

Pearson's correlation analysis showed that reduced HRQOL was strongly correlated with anxiety (r=-0.77, P=0.000), fatigue (r=-0.75, P=0.000) and depression (r=-0.73, P=0.000); and moderately correlated with disability (r=-0.53, P=0.000) and sleep disorder (r=-0.59, P=0.000). Stepwise regression analysis further revealed that anxiety was the best predictor of both the global and physical composite scores of HRQOL, followed by disability, fatigue and depression (global composite, r(2)=0.76, P=0.000; physical composite, r(2)=0.71, P=0.000). Depression, fatigue and anxiety were the main predictors of the mental health composite score of HRQOL (r(2)=0.69, P=0.000). Other factors did not have an effect on HRQOL.

CONCLUSIONS

This study revealed factors that impact HRQOL in NMOSD and provided the first demonstration that anxiety, disability, fatigue and depression are independent predictors of poor HRQOL in NMOSD.

A Case Study of Intractable Vomiting with Final Diagnosis of Neuromyelitis Optica

This case study presents a patient living in a suburban/rural community who received appropriate referral to secondary and tertiary care for nausea and vomiting, accompanied by waxing and waning neurological symptoms, yet proved difficult to diagnose. This patient is presented to draw attention to a rare neurological disorder which should be included in the differential diagnosis of nausea and vomiting with some key neurological complaints, even in the absence of physical findings.

Hypoxemia, Sleep Disturbances, and Depression Correlated with Fatigue in Neuromyelitis Optica Spectrum Disorder

AIMS

Among patients with neuromyelitis optica spectrum disorder (NMOSD), fatigue is commonly complained about and is one of the most debilitating symptoms. This study aimed to investigate the incidence of fatigue and explore impacting factors attributed to fatigue in NMOSD.

METHODS

Thirty-three patients with NMOSD and twenty matched healthy controls were enrolled. A battery of self-reported questionnaires was conducted to assess quality of sleep, daytime sleepiness, fatigue, depression, and level of activity of daily life. The structure of sleep was assessed by polysomnography with blood oxygen saturation monitored by noninvasive pulse oximeter. Brain and spinal cord lesions were evaluated by MRIs.

RESULTS

Fatigue was more severe and more prevalent among the patients with NMOSD compared with controls (fatigue score which ranges from 0 to 11 with higher scores indicating more severe fatigue: 6.4 ± 0.6 vs. 3.8 ± 0.4, P = 0.002; incidence, 64% vs. 35%, P = 0.043), and it was negatively associated with daily activity level (r = 0.455, P = 0.008). The patients with fatigue had higher Pittsburgh Sleep Quality Index score, higher Epworth Sleepiness Scale score, lower blood oxygen state, and higher depression score than patients without fatigue; blood oxygen was especially negatively correlated with fatigue (nadir SpO2 , r = -0.558, P = 0.001; mean SpO2 , r = -0.457, P = 0.007); depression was also positively correlated with fatigue (r = 0.599, P < 0.001).

CONCLUSION

Patients with NMOSD experienced significant fatigue, which had an obvious impact on their daily activity. Fatigue in these patients was related to hypoxemia, sleep disturbances, and depression.