SARS-CoV-2 and Multiple Sclerosis: Potential for Disease Exacerbation

Potential biomaterials and experimental animal models for inventing new drug delivery approaches in the neurodegenerative disorder: Multiple sclerosis

The tight junction of endothelial cells in the central nervous system (CNS) has an ideal characteristic, acting as a biological barrier that can securely regulate the movement of molecules in the brain. Tightly closed astrocyte cell junctions on blood capillaries are the blood-brain barrier (BBB). This biological barrier prohibits the entry of polar drugs, cells, and ions, which protect the brain from harmful toxins. However, delivering any therapeutic agent to the brain in neurodegenerative disorders (i.e., schizophrenia, multiple sclerosis, etc.) is extremely difficult. Active immune responses such as microglia, astrocytes, and lymphocytes cross the BBB and attack the nerve cells, which causes the demyelination of neurons. Therefore, there is a hindrance in transmitting electrical signals properly, resulting in blindness, paralysis, and neuropsychiatric problems. The main objective of this article is to shed light on the performance of biomaterials, which will help researchers to create nanocarriers that can cross the blood-brain barrier and achieve a therapeutic concentration of drugs in the CNS of patients with multiple sclerosis (MS). The present review focuses on the importance of biomaterials with diagnostic and therapeutic efficacy that can help enhance multiple sclerosis therapeutic potential. Currently, the development of MS in animal models is limited by immune responses, which prevent MS induction in healthy animals. Therefore, this article also showcases animal models currently used for treating MS. A future advance in developing a novel effective strategy for treating MS is now a potential area of research.

Occurrence and Risk Factors of Relapse Activity after Vaccination against COVID-19 in People with Multiple Sclerosis: 1-Year Follow-Up Results from a Nationwide Longitudinal Observational Study

Several studies reported post-SARS-CoV-2-vaccination (PV) symptoms. Even people with multiple sclerosis (PwMS) have concerns about disease activity following the SARS-CoV-2 vaccination. We aimed to determine the proportion of PwMS with PV relapses, the PV annualized relapse rate (ARR), the time from vaccination to subsequent relapses, and identify sociodemographic/clinical risk factors for PV relapses. PwMS were surveyed several times at baseline and four follow-ups as part of a longitudinal observational study regarding the safety and tolerability of the SARS-CoV-2 vaccination. The inclusion criteria for this analysis were age ≥18 years, ≥1 SARS-CoV-2 vaccination, and ≥1-year observation period since initial vaccination. Of 2466 PwMS, 13.8% reported PV relapses (mostly after second [N = 147] or booster vaccination [N = 145]) at a median of 8.0 (first/third quantile: 3.55/18.1) weeks PV, with the shortest period following initial vaccination (3.95 weeks). The ARR was 0.153 (95% confidence interval: 0.138-0.168), with a median observation period since initial vaccination of 1.2 years. Risk factors for PV relapses were younger age, female gender, moderate-severe disability levels, concurrent autoimmune diseases, relapsing-remitting MS courses, no DMT, and relapses within the year prior to the first vaccination. Patients' health conditions before/during initial vaccination may play a more important role in PV relapse occurrence than vaccination per se.

Transgenic mouse models support a protective role of type I IFN response in SARS-CoV-2 infection-related lung immunopathology and neuroinvasion

Type I interferon (IFN-I) response is the first line of host defense against invading viruses. In the absence of definite mouse models, the role of IFN-I in SARS-CoV-2 infection remains perplexing. Here, we develop two mouse models, one with constitutively high IFN-I response (hACE2; Irgm1-/-) and the other with dampened IFN-I response (hACE2; Ifnar1-/-), to comprehend the role of IFN-I response. We report that hACE2; Irgm1-/- mice are resistant to lethal SARS-CoV-2 infection. In contrast, a severe SARS-CoV-2 infection along with immune cell infiltration, cytokine storm, and enhanced pathology is observed in the lungs and brain of hACE2; Ifnar1-/- mice. The hACE2; Irgm1-/-Ifnar1-/- double-knockout mice display loss of the protective phenotype observed in hACE2; Irgm1-/- mice, suggesting that heightened IFN-I response accounts for the observed immunity. Taking the results together, we demonstrate that IFN-I protects from lethal SARS-CoV-2 infection, and Irgm1 (IRGM) could be an excellent therapeutic target against SARS-CoV-2.

Effect of the COVID-19 pandemic on disease activity in multiple sclerosis patients treated with hematopoietic stem cell transplantation

BACKGROUND AND PURPOSE

It is still debated whether the COVID-19 pandemic affected disease activity in people with autoimmune diseases, including multiple sclerosis (MS). The aim of this study, therefore, was to explore the impact of COVID-19 in people with MS (pwMS) not receiving continuative disease-modifying therapy (DMT) after previous treatment with autologous hematopoietic stem cell transplantation (AHSCT).

MATERIALS AND METHODS

We included pwMS treated with AHSCT who were in disease remission without receiving DMTs during the pandemic and who were followed up at our centre during the study period. Data on SARS-CoV-2 infection and vaccination were recorded, with details of adverse events and clinical-radiological disease activity.

RESULTS

A total of 36 pwMS (31 females; 86%) were included, of whom 23 (64%) had relapsing-remitting (RR-MS) and 13 had secondary progressive MS (SP-MS). Thirty-three pwMS (92%) received anti-SARS-CoV-2 mRNA vaccines. Thirteen patients (36%) developed mild to moderate COVID-19 a median (range) of 58 (4-224) months after AHSCT; seven (54%) of these patients were not yet vaccinated. Transient neurological symptoms after vaccination or infection were reported in 9% and 36% of the patients, respectively. The rate of new inflammatory events (relapses or asymptomatic magnetic resonance imaging [MRI] activity) after AHSCT increased from 0.006 (one asymptomatic new lesion/159 patient-years) before the pandemic to 0.083 (five relapses plus two cases of asymptomatic MRI activity/84 patient-years) since the pandemic start (p = 0.004).

CONCLUSIONS

People with MS with a history of highly active disease, who are untreated or receiving moderate-efficacy DMTs might be more vulnerable to disease reactivation, possibly elicited by exogenous triggers. Careful monitoring and further investigation are warranted to ascertain whether special precautions are needed in these cases.

The Potential Role of SARS-CoV-2 Infection and Vaccines in Multiple Sclerosis Onset and Reactivation: A Case Series and Literature Review

The recent SARS-CoV-2 pandemic and related vaccines have raised several issues. Among them, the potential role of the viral infection (COVID-19) or anti-SARS-CoV-2 vaccines as causal factors of dysimmune CNS disorders, as well as the safety and efficacy of vaccines in patients affected by such diseases and on immune-active treatments have been analyzed. The aim is to better understand the relationship between SARS-CoV-2 infection/vaccines with dysimmune CNS diseases by describing 12 cases of multiple sclerosis/myelitis onset or reactivation after exposure to SARS-CoV-2 infection/vaccines and reviewing all published case reports or case series in which MS onset or reactivation was temporally associated with either COVID-19 (8 case reports, 3 case series) or anti-SARS-CoV-2 vaccines (13 case reports, 6 case series). All the cases share a temporal association between viral/vaccine exposure and symptoms onset. This finding, together with direct or immune-based mechanisms described both during COVID-19 and MS, claims in favor of a role for SARS-CoV-2 infection/vaccines in unmasking dysimmune CNS disorders. The most common clinical presentations involve the optic nerve, brainstem and spinal cord. The preferential tropism of the virus together with the presence of some host-related genetic/immune factors might predispose to the involvement of specific CNS districts.

Evaluation of the safety profile of COVID-19 vaccines in patients with MS, NMOSD, and MOGAD

INTRODUCTION

Vaccination against the coronavirus disease 2019 (COVID-19) is recommended for patients with multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). However, vaccine safety in these patients taking immunotherapeutic agents is unclear as they were not included in the vaccine trials.

OBJECTIVES

To evaluate the safety of COVID-19 vaccines in patients with MS, NMOSD, and MOGAD.

METHODS

We reviewed the medical records of MS, NMOSD, and MOGAD patients at the Keimyung University Dongsan Hospital. Information regarding vaccination schedules and adverse events was collected.

RESULTS

A total of 56 patients (19, 22, and 15 patients with MS, NMOSD, and MOGAD, respectively) with a median age of 48.18 ± 15.72 years (range, 16-81 years) were included. Of them, 42 (75.0%) were female. In total, 76.8% (43/56) of all patients were vaccinated, and the vaccination rate was the highest for NMOSD patients (81.8%) and the lowest for MS patients (68.4%). All vaccinated patients were administered mRNA vaccines at least once in single or multiple vaccination doses. Only 3 of 43 (7.0%) vaccinated patients experienced clinical relapse following vaccination. Facial sensory changes with a brainstem lesion developed in an MS patient taking dimethyl fumarate, while myelitis occurred in a MOGAD patient receiving azathioprine maintenance therapy. The first episode of optic neuritis occurred in a patient who was later diagnosed with MOGAD.

CONCLUSIONS

Our study demonstrated a favorable safety profile with no serious adverse events associated with COVID-19 vaccines in patients with MS, NMOSD, and MOGAD.

Role of Demyelination in the Persistence of Neurological and Mental Impairments after COVID-19

Long-term neurological and mental complications of COVID-19, the so-called post-COVID syndrome or long COVID, affect the quality of life. The most persistent manifestations of long COVID include fatigue, anosmia/hyposmia, insomnia, depression/anxiety, and memory/attention deficits. The physiological basis of neurological and psychiatric disorders is still poorly understood. This review summarizes the current knowledge of neurological sequelae in post-COVID patients and discusses brain demyelination as a possible mechanism of these complications with a focus on neuroimaging findings. Numerous reviews, experimental and theoretical studies consider brain demyelination as one of the mechanisms of the central neural system impairment. Several factors might cause demyelination, such as inflammation, direct effect of the virus on oligodendrocytes, and cerebrovascular disorders, inducing myelin damage. There is a contradiction between the solid fundamental basis underlying demyelination as the mechanism of the neurological injuries and relatively little published clinical evidence related to demyelination in COVID-19 patients. The reason for this probably lies in the fact that most clinical studies used conventional MRI techniques, which can detect only large, clearly visible demyelinating lesions. A very limited number of studies use specific methods for myelin quantification detected changes in the white matter tracts 3 and 10 months after the acute phase of COVID-19. Future research applying quantitative MRI assessment of myelin in combination with neurological and psychological studies will help in understanding the mechanisms of post-COVID complications associated with demyelination.

Gut-brain communication in COVID-19: molecular mechanisms, mediators, biomarkers, and therapeutics

INTRODUCTION

Infection with COVID-19 results in acute respiratory symptoms followed by long COVID multi-organ effects presenting with neurological, cardiovascular, musculoskeletal, and gastrointestinal (GI) manifestations. Temporal relationship between gastrointestinal and neurological symptoms is unclear but warranted for exploring better clinical care for COVID-19 patients.

AREAS COVERED

We critically reviewed the temporal relationship between gut-brain axis after SARS-CoV-2 infection and the molecular mechanisms involved in neuroinvasion following GI infection. Mediators are identified that could serve as biomarkers and therapeutic targets in SARS-CoV-2. We discussed the potential therapeutic approaches to mitigate the effects of GI infection with SARS-CoV-2.

EXPERT OPINION

Altered gut microbiota cause increased expression of various mediators, including zonulin causing disruption of tight junction. This stimulates enteric nervous system and signals to CNS precipitating neurological sequalae. Published reports suggest potential role of cytokines, immune cells, B(0)AT1 (SLC6A19), ACE2, TMRSS2, TMPRSS4, IFN-γ, IL-17A, zonulin, and altered gut microbiome in gut-brain axis and associated neurological sequalae. Targeting these mediators and gut microbiome to improve immunity will be of therapeutic significance. In-depth research and well-designed large-scale population-based clinical trials with multidisciplinary and collaborative approaches are warranted. Investigating the temporal relationship between organs involved in long-term sequalae is critical due to evolving variants of SARS-CoV-2.