Multiple sclerosis and inflammatory bowel diseases: a systematic review and meta-analysis

Perivascular B cells link intestinal angiogenesis to immunity and to the gut-brain axis during neuroinflammation

Disruption of gut barrier function and intestinal immune cell homeostasis are increasingly considered critical players in pathogenesis of extra-intestinal inflammatory diseases, including multiple sclerosis (MS) and its prototypical animal model, the experimental autoimmune encephalomyelitis (EAE). Breakdown of epithelial barriers increases intestinal permeability and systemic dissemination of microbiota-derived molecules. However, whether the gut-vascular barrier (GVB) is altered during EAE has not been reported. Here, we demonstrate that endothelial cell proliferation and vessel permeability increase before EAE clinical onset, leading to vascular remodeling and expansion of intestinal villi capillary bed during disease symptomatic phase in an antigen-independent manner. Concomitant to onset of angiogenesis observed prior to neurological symptoms, we identify an increase of intestinal perivascular immune cells characterized by the surface marker lymphatic vessel endothelial hyaluronic acid receptor 1 (LYVE-1). LYVE-1+ is expressed more frequently on B cells that show high levels of CD73 and have proangiogenic properties. B cell depletion was sufficient to mitigate enteric blood endothelial cell proliferation following immunization for EAE. In conclusion, we propose that altered intestinal vasculature driven by a specialized LYVE-1+ B cell subset promotes angiogenesis and that loss of GVB function is implicated in EAE development and autoimmunity.

Risk of Neuroinflammatory Diseases Among New Recipients of Biologic and Targeted Synthetic Disease-Modifying Antirheumatic Drugs

OBJECTIVE

Neuroinflammatory adverse events have been observed among new users of tumor necrosis factor (TNF) inhibitors. No studies to date have compared the real-world risk of TNFs with other new users of biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs). The objective of this study is to describe the risk of neuroinflammatory disease after initiation b/tsDMARDs.

METHODS

This new user comparative effectiveness cohort study used a large US-based electronic health records database to describe the unadjusted incidence of neuroinflammatory adverse events over a 3-year period. The cohort included patients with rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, or ulcerative colitis initiating treatment with a TNF inhibitor (n = 93,661) or other b/tsDMARD (n = 38,354).

RESULTS

Among 132,015 patients included in the analysis, the most common first biologic agent was a TNF inhibitor; the unadjusted incidence of neuroinflammatory events was numerically lower among new users of TNF inhibitors (incidence 1.34 per 1,000 patient-years) as compared with the combined non-TNF group (1.69 per 1,000 patient-years). There was no significant association between TNF exposure and neuroinflammatory events as compared with the combined non-TNF b/tsDMARDs overall (hazard ratio 1.01; 95% confidence interval 0.75-1.36) and within each disease group.

CONCLUSION

The overall risk of neuroinflammatory events among new users of TNF inhibitors did not differ substantially as compared with new users of other b/tsDMARDs. Meta-analyses of randomized trials should be conducted to corroborate these findings, which may be affected by channeling bias.

Incidence and predictors of demyelinating disease in spondyloarthritis: data from a longitudinal cohort study

OBJECTIVES

The objectives of this study were to investigate the incidence of demyelinating disease (DD) among SpA patients and to identify risk factors that predict DD in this patient population.

METHODS

Axial SpA (axSpA) and PsA patients were identified from a longitudinal cohort database. Each group was analysed according to the presence or absence of DD. Incidence rates (IRs) of DD were obtained, with competing risk analysis. Cox regression analysis (with Fine and Gray's method) was used to evaluate predictors of DD development.

RESULTS

Among 2260 patients with follow-up data, we identified 18 DD events, corresponding to an average IR of 31 per 100 000 persons per year for SpA. The IR of DD at 20 years was higher in axSpA than in PsA (1.30% vs 0.13%, P = 0.01). The risk factors retained in the best predictive model for DD development included ever- (vs never-) smoking [hazard ratio (HR) 2.918, 95% CI 1.037-8.214, P = 0.0426], axSpA (vs PsA) (HR 8.790, 95% CI 1.242-62.182, P = 0.0294) and presence (vs absence) of IBD (HR 5.698, 95% CI 2.083-15.589, P = 0.0007). History of TNF-α inhibitor therapy was not a predictor of DD.

CONCLUSION

The overall incidence of DD in this SpA cohort was low. Incident DD was higher in axSpA than in PsA. A diagnosis of axSpA, the presence of IBD, and ever-smoking predicted the development of DD. History of TNF-α inhibitor use was not found to be a predictor of DD in this cohort.

Concomitant autoimmunity and risk of multiple sclerosis disability worsening

BACKGROUND

Few studies have examined the effect of concomitant autoimmune diseases on multiple sclerosis (MS) disability worsening. We set out to examine whether concomitant Crohn's Disease (CD), Ulcerative Colitis (UC), or Type 1 Diabetes (T1D) affect MS disability worsening in a nationwide cohort of MS patients as defined by reaching expanded disability scale status (EDSS) scores 3.0, 4.0 and 6.0.

METHODS

Patients with MS onset between January 2004 and January 2019 were identified from the Swedish MS registry and the Swedish National Patient Register. Kaplan-Meier analysis was used to estimate the median time to reach sustained disability milestones. Adjusted Cox proportional hazard regression models were used to calculate the risk of reaching disability milestones among persons with and without CD, UC, or T1D.

RESULTS

Out of 8972 persons with MS, 88 (1.0 %) had T1D, 47 (0.8 %) had UC, and 78 (0.9 %) had CD. There was a significantly higher risk of disability progression, for persons with MS and T1D for reaching EDSS 6.0, hazard ratio (HR) = 2.21 (95 % confidence interval (CI) = 1.48 -3.31) and persons with MS and comorbid CD for reaching EDSS 3.0, HR = 2.30 (95 %CI = 1.74-3.04) and 4.0, HR = 1.59 (95 %CI = 1.09-2.32), and persons with MS and comorbid UC for reaching EDSS 3.0 HR = 1.57 (95 %CI = 1.15-2.14). As defined by Charlson's comorbidity index, the co-existence of other co-morbidities conferred a significant increase in the risk of reaching all endpoints, with HR ranging from 1.23 to 1.62.

CONCLUSION

Comorbidity is associated with a significantly increased risk of reaching disability end-points, and T1D, CD, and UC increase the risk further. Thus, there appears to be a need for increased vigilance of comorbidites in persons with MS in order to optimise the long-term outcome of MS.

Association of Crohn's disease and ulcerative colitis with the risk of neurological diseases: a large-scale Mendelian randomization study

Observational studies suggested increased risks of Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS) in patients with Crohn's disease (CD) and ulcerative colitis (UC). We aimed to assess the causality for the associations of CD and UC with the risks of AD, PD, and MS through a two-sample Mendelian randomization (MR) study. Independent single nucleotide polymorphisms associated with CD (17,897 cases and 33,977 controls) and UC (13,768 cases and 33,977 controls) were identified as genetic instruments based on a European-descent genome-wide association study (GWAS) released by the International Inflammatory Bowel Disease Genetics Consortium. Summary statistics for AD (combined: 25,881 cases and 256,837 controls), PD (combined: 35,836 cases and 665,686 controls), and MS (combined: 48,477 cases and 285,515 controls) were obtained from the largest GWASs and FinnGen study of European ancestry, respectively. MR estimates were generated using the inverse-variance weighted method in the main analysis with a series of sensitivity analyses. MR analyses were conducted per outcome database and were subsequently meta-analyzed to generate combined estimates. Genetically predicted UC was significantly associated with increased risks of AD (combined: OR, 1.03; 95% CI, 1.01-1.05; P = 1.80 × 10-3) and MS (combined: OR, 1.37; 95% CI, 1.23-1.53; P = 1.18 × 10-8), while there was no association between genetically predicted UC and the risk of PD. In contrast, no significant associations were observed for genetically predicted CD with AD, PD, and MS. MR-Egger regression showed no directional pleiotropy for the identified associations, and sensitivity analyses with different MR methods further confirmed these findings. This study suggested significant adverse effects of UC on AD and MS, highlighting that UC patients should receive early intervention with optimal adjunctive medical therapy to reduce the risks of AD and MS.

Gut microbiota in multiple sclerosis and animal models

Multiple sclerosis (MS) is a chronic central nervous system (CNS) neurodegenerative and neuroinflammatory disease marked by a host immune reaction that targets and destroys the neuronal myelin sheath. MS and correlating animal disease models show comorbidities, including intestinal barrier disruption and alterations of the commensal microbiome. It is accepted that diet plays a crucial role in shaping the microbiota composition and overall gastrointestinal (GI) tract health, suggesting an interplay between nutrition and neuroinflammation via the gut-brain axis. Unfortunately, poor host health and diet lead to microbiota modifications that could lead to significant responses in the host, including inflammation and neurobehavioral changes. Beneficial microbial metabolites are essential for host homeostasis and inflammation control. This review will highlight the importance of the gut microbiota in the context of host inflammatory responses in MS and MS animal models. Additionally, microbial community restoration and how it affects MS and GI barrier integrity will be discussed.

Similar geographic distribution of mortality from multiple sclerosis, Hodgkin lymphoma, and inflammatory bowel disease in the United States

BACKGROUND

Previous epidemiologic studies have suggested a linkage between the occurrence of multiple sclerosis (MS), Hodgkin lymphoma (HL), Crohn's disease (CD), and ulcerative colitis (UC). It was hypothesized that the 4 diagnoses would be characterized by similar geographic distributions within the United States.

AIMS

To compare the US geographic distributions of these 4 diagnoses in a cross-sectional study.

METHODS

Using the US vital statistics, state-specific death rates and age-specific proportional mortality ratios (PMR) were calculated for each diagnosis. Similarities in the geographic distributions of the 4 diagnoses were tested by linear and Poisson regression analyses. The PMR values from different states were correlated among pairs of consecutive age-groups.

RESULTS

The 6 linear correlation coefficients (r) among the geographic distributions of the 4 diseases were as follows: HL vs. MS (r = 0.28), HL vs. CD (r = 0.74), HL vs. UC (r = 0.64); MS vs. CD (r = 0.18), MS vs. UC (r = 0.66); CD vs. UC (r = 0.58). Using Poisson regression, the geographic distributions of MS, HL, CD, and UC were all found to be significantly correlated with each other. In MS, significant correlations between the PMR values of each two consecutive age-groups started with the age-group 25-44 years. In HL, such significant correlations started at age 10-14, in CD at age 20-24, and in UC at age 20-24 years.

CONCLUSIONS

Within the United States, mortality from MS, HL, CD, and UC are characterized by similar geographic distributions. The environmental influences responsible for these resembling geographic distributions start exerting their influence during early lifetime.

A leaky gut dysregulates gene networks in the brain associated with immune activation, oxidative stress, and myelination in a mouse model of colitis

The gut and brain are increasingly linked in human disease, with neuropsychiatric conditions classically attributed to the brain showing an involvement of the intestine and inflammatory bowel diseases (IBDs) displaying an ever-expanding list of neurological comorbidities. To identify molecular systems that underpin this gut-brain connection and thus discover therapeutic targets, experimental models of gut dysfunction must be evaluated for brain effects. In the present study, we examine disturbances along the gut-brain axis in a widely used murine model of colitis, the dextran sodium sulfate (DSS) model, using high-throughput transcriptomics and an unbiased network analysis strategy coupled with standard biochemical outcome measures to achieve a comprehensive approach to identify key disease processes in both colon and brain. We examine the reproducibility of colitis induction with this model and its resulting genetic programs during different phases of disease, finding that DSS-induced colitis is largely reproducible with a few site-specific molecular features. We focus on the circulating immune system as the intermediary between the gut and brain, which exhibits an activation of pro-inflammatory innate immunity during colitis. Our unbiased transcriptomics analysis provides supporting evidence for immune activation in the brain during colitis, suggests that myelination may be a process vulnerable to increased intestinal permeability, and identifies a possible role for oxidative stress and brain oxygenation. Overall, we provide a comprehensive evaluation of multiple systems in a prevalent experimental model of intestinal permeability, which will inform future studies using this model and others, assist in the identification of druggable targets in the gut-brain axis, and contribute to our understanding of the concomitance of intestinal and neuropsychiatric dysfunction.

Risk of Common Neurological Disorders in Adult Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

BACKGROUND

Several studies investigated the risks of neurological conditions in patients with inflammatory bowel disease (IBD), with some variability in findings. We aimed to perform a systematic review and meta-analysis of available evidence to elucidate the association between IBD and the risks of common neurological disorders.

METHODS

We conducted a literature search through Embase, PubMed, Scopus, and ProQuest databases from inception to June 30, 2023, to identify cohort studies assessing the risk of developing stroke, all-cause dementia, Parkinson's disease (PD), multiple sclerosis (MS), seizure/epilepsy, and peripheral neuropathy in adult IBD patients compared with non-IBD population. We combined hazard ratios (HRs) with 95% confidence intervals (CIs) to compute pooled estimates using a random-effects model.

RESULTS

In total, 22 cohort studies were included, of which 9 studies reported 7074 stroke events in 202 460 IBD patients, 5 studies reported 3783 all-cause dementia diagnoses in 109 602 IBD patients, 7 studies reported 932 PD diagnoses in 354 792 IBD patients, and 1 study reported 6 MS events in 35 581 IBD patients. We observed increased risks of incident stroke (pooled HR = 1.19; 95% CI, 1.06-1.31), all-cause dementia (pooled HR = 1.22; 95% CI, 1.05-1.38), PD (pooled HR = 1.39; 95% CI, 1.20-1.58), and MS (HR = 2.89; 95% CI, 1.02-8.42). No eligible studies were found on peripheral neuropathy and seizure/epilepsy.

CONCLUSIONS

Inflammatory bowel disease may be modestly associated with increased risks of stroke, all-cause dementia, and PD. Further longitudinal studies are warranted to investigate potential links with MS, seizure/epilepsy, and peripheral neuropathy, as well as their clinical significance.

Gut microbiota does not play a mediating role in the causal association between inflammatory bowel disease and several its associated extraintestinal manifestations: a Mendelian randomization study

Background and objectives

Observational study has found inflammatory bowel disease to be associated with multiple extraintestinal manifestations. To this end, we characterized the causal association between inflammatory bowel disease and extraintestinal manifestations through a Mendelian randomization study and further explored the role of intestinal flora in inflammatory bowel disease and the extraintestinal manifestations associated with it.

Materials and methods

We genetically predicted the causal relationship between inflammatory bowel disease and twenty IBD-related extraintestinal manifestations (including sarcoidosis, iridocyclitis, interstitial lung disease, atopic dermatitis, ankylosing spondylitis, psoriatic arthropathies, primary sclerosing cholangitis, primary biliary cholangitis). We used the full genome-wide association study (GWAS) summary statistics on gut microbiota in 18,340 participants from 24 cohorts to explore its role in the casual relationships between IBD and IBD-related extraintestinal manifestations. Inverse variance weighting (IVW) was used as the main analytical method to assess the causal associations. We performed Cochran's Q test to examine the heterogeneity. To assess the robustness of the IVW results, we further performed sensitivity analyses including the weighted median method, MR-Egger regression, and Mendelian Randomization Pleiotropy RESidual Sum and Outlier (MR-PRESSO) test. The leave-one-out sensitivity analysis was further performed to monitor if significant associations were dominated by a single nucleotide polymorphism (SNP).

Result

A total of eight extraintestinal manifestations were found to be at elevated risk of development due to inflammatory bowel diseases. A total of 11 causal relationships were found between IBD and gut microbiota, four of which were stable. Between gut microbiota and these eight extraintestinal manifestations, a total of 67 nominal causal associations were identified, of which 13 associations were stable, and notably 4 associations were strongly correlated.

Conclusion

Through the two-sample MR analysis, we identified extraintestinal manifestations that were causally associated with inflammatory bowel disease and obtained multiple associations from inflammatory bowel disease and gut microbiota, and gut microbiota and extraintestinal manifestations in further analyses. These associations may provide useful biomarkers and potential targets for pathogenesis and treatment.

Concurrence of inflammatory bowel disease with multiple sclerosis or Hodgkin lymphoma

BACKGROUND AND AIMS

Epidemiologic evidence suggests that Hodgkin lymphoma (HL) and multiple sclerosis (MS) share a common set of risk factors with Crohn's disease (CD) and ulcerative colitis (UC). It was hypothesized that such shared risk factors would lead to clustering of the 4 diagnoses in the same patients.

METHODS

All patients with HL, MS, CD, or UC were identified in the veterans population from 2016-2020 and the Medicare population from 1986 to 1989. In a case-control study, the observed concurrences amongst these 4 diagnoses were compared with their expected frequencies in the overall veterans or Medicare population during the same time period by calculating odds ratios (OR) with their 95% confidence intervals (CI).

RESULTS

The study included 6 million veterans and 35 million Medicare patients. In the veterans population, inflammatory bowel disease (IBD) was significantly associated with a concurrent diagnosis of HL (OR: 1.40, 95% CI: 1.15-1.71) and MS (1.34, 1.19-1.50). In the Medicare population, IBD was also significantly associated with HL (1.84, 1.07-3.17) and MS (2.31, 1.59-3.35). Similar trends were observed in CD or UC when analyzed separately in both datasets. In the veterans population, adjustment for the potentially confounding influence of ethnicity, sex, and age left all OR values largely unaffected and statistically significant.

CONCLUSION

The concurrence of IBD with HL or MS could reflect on a common pathway in the etiology or pathogenesis of these 4 diseases.

Impact of Microbiome-Brain Communication on Neuroinflammation and Neurodegeneration

The gut microbiome plays a pivotal role in maintaining human health, with numerous studies demonstrating that alterations in microbial compositions can significantly affect the development and progression of various immune-mediated diseases affecting both the digestive tract and the central nervous system (CNS). This complex interplay between the microbiota, the gut, and the CNS is referred to as the gut-brain axis. The role of the gut microbiota in the pathogenesis of neurodegenerative diseases has gained increasing attention in recent years, and evidence suggests that gut dysbiosis may contribute to disease development and progression. Clinical studies have shown alterations in the composition of the gut microbiota in multiple sclerosis patients, with a decrease in beneficial bacteria and an increase in pro-inflammatory bacteria. Furthermore, changes within the microbial community have been linked to the pathogenesis of Parkinson's disease and Alzheimer's disease. Microbiota-gut-brain communication can impact neurodegenerative diseases through various mechanisms, including the regulation of immune function, the production of microbial metabolites, as well as modulation of host-derived soluble factors. This review describes the current literature on the gut-brain axis and highlights novel communication systems that allow cross-talk between the gut microbiota and the host that might influence the pathogenesis of neuroinflammation and neurodegeneration.

Immune-mediated colitis associated with ocrelizumab: A new safety risk

BACKGROUND

An association between certain immunomodulatory therapies (rituximab, ipilimumab, and other immune checkpoint inhibitors) and inflammatory (non-ischemic and non-infectious) colitis in oncologic and non-oncologic patient populations is well documented in the medical literature.

OBJECTIVE

The purpose of this case series is to describe adverse event reports of new onset, inflammatory colitis in association with ocrelizumab in patients with multiple sclerosis submitted to U.S. Food and Drug Administration (FDA) or published in the medical literature.

METHODS

The FDA Adverse Event Reporting System (FAERS) and medical literature were searched.

RESULTS

A review of postmarketing cases from FAERS and published medical literature identified 38 cases consistent with inflammatory, non-ischemic, and non-infectious colitis in association with ocrelizumab. The median time-to-onset was 8 months. Cases were reported using the following diagnostic terms: Crohn's disease (13), unspecified colitis (11), microscopic colitis (5), ulcerative colitis (5), medication-induced colitis (3), and autoimmune colitis (2).

CONCLUSIONS

This case series highlights ocrelizumab induced immune-mediated colitis that can be clinically severe and potentially life-threatening. Based on the findings of this review, the ocrelizumab Prescribing Information was amended to include immune-mediated colitis in the Warnings and Precautions section.

A leaky gut dysregulates gene networks in the brain associated with immune activation, oxidative stress, and myelination in a mouse model of colitis

The gut and brain are increasingly linked in human disease, with neuropsychiatric conditions classically attributed to the brain showing an involvement of the intestine and inflammatory bowel diseases (IBDs) displaying an ever-expanding list of neurological comorbidities. To identify molecular systems that underpin this gut-brain connection and thus discover therapeutic targets, experimental models of gut dysfunction must be evaluated for brain effects. In the present study, we examine disturbances along the gut-brain axis in a widely used murine model of colitis, the dextran sodium sulfate (DSS) model, using high-throughput transcriptomics and an unbiased network analysis strategy coupled with standard biochemical outcome measures to achieve a comprehensive approach to identify key disease processes in both colon and brain. We examine the reproducibility of colitis induction with this model and its resulting genetic programs during different phases of disease, finding that DSS-induced colitis is largely reproducible with a few site-specific molecular features. We focus on the circulating immune system as the intermediary between the gut and brain, which exhibits an activation of pro-inflammatory innate immunity during colitis. Our unbiased transcriptomics analysis provides supporting evidence for immune activation in the brain during colitis, suggests that myelination may be a process vulnerable to increased intestinal permeability, and identifies a possible role for oxidative stress and brain oxygenation. Overall, we provide a comprehensive evaluation of multiple systems in a prevalent experimental model of intestinal permeability, which will inform future studies using this model and others, assist in the identification of druggable targets in the gut-brain axis, and contribute to our understanding of the concomitance of intestinal and neuropsychiatric dysfunction.

Inflammatory Bowel Disease and Neurodegenerative Diseases

A growing body of evidence has demonstrated an intricate association between inflammatory bowel disease (IBD) and neurodegenerative conditions, expanding beyond previous foci of comorbidities between IBD and mood disorders. These new discoveries stem from an improved understanding of the gut-microbiome-brain axis: specifically, the ability of the intestinal microbiota to modulate inflammation and regulate neuromodulatory compounds. Clinical retrospective studies incorporating large sample sizes and population-based cohorts have demonstrated and confirmed the relevance of IBD and chronic neurodegeneration in clinical medicine. In this review, we expound upon the current knowledge on the gut-microbiome-brain axis, highlighting several plausible mechanisms linking IBD with neurodegeneration. We also summarize the known associations between IBD with Parkinson disease, Alzheimer disease, vascular dementia and ischemic stroke, and multiple sclerosis in a clinical context. Finally, we discuss the implications of an improved understanding of the gut-microbiome-brain axis in preventing, diagnosing, and managing neurodegeneration among IBD and non-IBD patients.

Multiple sclerosis and ulcerative colitis: A systematic review and meta-analysis

Background

Comorbidity is a current area of interest in multiple sclerosis (MS) and is essential for multidisciplinary management. Although recent studies suggest that patients with MS have an elevated risk of developing inflammatory bowel diseases (IBD), this systematic review and meta-analysis aimed to estimate the overall risk of developing ulcerative colitis (UC), specifically in patients with MS.

Methods

In 2021, a comprehensive literature search was performed on PubMed, Scopus, Embase, and Web of Science to identify studies investigating the association between UC and MS. The selected papers were utilized to estimate the associations, risk ratios (RRs), and a 95% confidence interval (CI).

Results

The analysis revealed a slightly elevated risk of UC incidence in patients with MS compared to controls, but this finding was not statistically significant (RR: 1.27 [95% CI: 0.96-1.67]). In contrast, the study found that patients with UC have a significantly higher risk of developing MS than controls (RR: 1.66 [95% CI: 1.15-2.40]).

Conclusion

Our findings highlight that the presence of UC increases the risk of developing MS by more than 50%, whereas the presence of MS does not increase the risk of UC occurrence. These results underscore the importance of considering the potential development of UC in the clinical management and early diagnosis of patients with MS, as it may contribute to better therapeutic outcomes.

Neurologic Manifestations of Gastrointestinal and Nutritional Disorders

OBJECTIVE

A tie between nutritional or gastrointestinal and neurologic disease has been recognized for centuries. Many gastrointestinal disorders are associated with neurologic disease through nutritional, immune-mediated, or degenerative pathophysiologies. This article reviews neurologic disorders in patients with gastrointestinal disease and gastrointestinal manifestations in their own neurologic patients.

LATEST DEVELOPMENTS

Development of new gastric and bariatric surgical procedures and the widespread use of over-the-counter gastric acid-reducing medications continue to create vitamin and nutritional deficiencies despite modern diet and supplementation. Some supplements, such as vitamin A, vitamin B6, and selenium, themselves are now found to cause disease. Recent work has shown extraintestinal and neurologic manifestations of inflammatory bowel disease. Chronic brain damage in liver disease has been recognized, and the opportunity to intervene may exist in the covert beginning stages. The characterization of gluten-related neurologic symptoms and differentiation from those of celiac disease is an evolving body of work.

ESSENTIAL POINTS

Gastrointestinal and neurologic diseases related to common immune-mediated, degenerative, or infectious mechanisms are common and can coexist in the same patient. Furthermore, gastrointestinal disease may cause neurologic complications because of nutritional inadequacies, malabsorption, and hepatic dysfunction. In many cases, the complications are treatable but have subtle or protean presentations. Therefore, the consulting neurologist must be current in knowledge of the growing ties between gastrointestinal and neurologic disease.

Tumor necrosis factor-α inhibitor-related immune disorders

Biotechnological monoclonal antibodies and receptor antagonists capable of targeting specific inflammatory actors, such as cytokines, cytokines receptors, co-stimulatory molecules or leukocyte populations, have emerged as an alternative to conventional therapies for treating systemic inflammatory diseases with immune pathogenesis. However, there is no doubt that, with a frequency that is not exceptionally high but also not negligible, immunotherapies can favour the development of systemic and organ-specific immune-mediated disorders. It has become increasingly evident that interference with a specific immune pathway may favour the activation of opposing compensatory signalling, which may exacerbate underlying subclinical disorders or cause immune-mediated diseases completely different from the underlying disease. The 'compensatory immunological switch' has emerged primarily in patients treated with tumor necrosis factor (TNF) -α inhibitors, the first biological drugs approved for treating systemic inflammatory diseases with immune pathogenesis. In this Review, we describe the clinical features and predisposing factors of the main TNF-α inhibitor-related immune disorders, organising them into subclinical serological autoimmunity, autoimmune disorders other than those for which TNF-α inhibitors are indicated, and paradoxical reactions. We also discuss the underlying pathogenetic mechanisms and precautions for use in the therapeutic management of these patients. Better understanding of the complex phenomenon of the 'compensatory immunological switch', which TNF-α inhibitors and other biological drugs might trigger, can help not only appropriately managing immune-mediated disorders, but also better interpreting the heterogeneity of the pathogenetic mechanisms underlying certain chronic inflammatory conditions that, although different from each other, are arbitrarily placed in the context of overly generic nosological entities.

Multiple Sclerosis and Autoimmune Comorbidities

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system characterized by broad inter- and intraindividual heterogeneity and different prognoses. Multisystem comorbidities are frequent features in people with MS (PwMS) and can affect treatment choices, quality of life, disability and mortality. In this scenario, autoimmune comorbidities play a cardinal role for several reasons, such as the implication on MS pathogenesis, diagnostic delay, disease activity, disability progression, brain atrophy, and treatment choice. However, the impact of an autoimmune comorbid condition on MS is not fully elucidated. This review aims to summarize the currently available data on the incidence and prevalence of autoimmune diseases in PwMS, the possible effect of this association on clinical and neuroradiological MS course and its impact on treatment choice.

Seizures and multiple sclerosis‑more than an epidemiological association (Review)

In order to increase the quality of life of patients with epilepsy, it is essential to develop tools that facilitate early disease diagnosis and encourage the use of individualized therapies. The association between seizures and other neurological pathologies is well known but incompletely explained, with multiple sclerosis (MS)-seizures correlation being a relevant example. In this context, the present review aimed to highlight the most important facts related to the association between the heterogeneous group of epileptic pathology and MS, in order to provide initial directions for establishing a diagnostic and therapeutic protocol. The first part reviewed the most relevant epidemiological and clinical data on seizures; MS association. Subsequently, it highlighted the most common and actually accepted pathophysiological mechanisms that try to explain the association between the two pathologies. Finally, the importance of paraclinical investigations and the optimal choice of antiseizure-based therapies with respect to seizures associated with MS are presented, also revealing several directions that should be explored in the near future.

Fecal Lcn-2 level is a sensitive biological indicator for gut dysbiosis and intestinal inflammation in multiple sclerosis

Multiple Sclerosis (MS) has been reported to be associated with intestinal inflammation and gut dysbiosis. To elucidate the underlying biology of MS-linked gut inflammation, we investigated gut infiltration of immune cells during the development of spontaneous experimental autoimmune encephalomyelitis (EAE) in humanized transgenic (Tg) mice expressing HLA-DR2a and human T cell receptor (TCR) specific for myelin basic protein peptide (MBP87-99)/HLA-DR2a complexes. Strikingly, we noted the simultaneous development of EAE and colitis, suggesting a link between autoimmune diseases of the central nervous system (CNS) and intestinal inflammation. Examination of the colon in these mice revealed the infiltration of MBP-specific Th17 cells as well as recruitment of neutrophils. Furthermore, we observed that fecal Lipocalin-2 (Lcn-2), a biomarker of intestinal inflammation, was significantly elevated and predominantly produced by the gut-infiltrating neutrophils. We then extended our findings to MS patients and demonstrate that their fecal Lcn-2 levels are significantly elevated compared to healthy donors (HDs). The elevation of fecal Lcn-2 levels correlated with reduced bacterial diversity and increased levels of other intestinal inflammation markers including neutrophil elastase and calprotectin. Of interest, bacteria thought to be beneficial for inflammatory bowel disease (IBD) such as Anaerobutyricum, Blautia, and Roseburia, were reduced in fecal Lcn-2-high MS patients. We also observed a decreasing trend in serum acetate (a short-chain fatty acid) levels in MS Lcn-2-high patients compared to HDs. Furthermore, a decrease in the relative abundance of Blautia massiliensis was significantly associated with a reduction of acetate in the serum of MS patients. This study suggests that gut infiltration of Th17 cells and recruitment of neutrophils are associated with the development of gut dysbiosis and intestinal inflammation, and that fecal Lcn-2 level is a sensitive biological indicator for gut dysbiosis in multiple sclerosis.

Efficacy of diet on fatigue, quality of life and disability status in multiple sclerosis patients: rapid review and meta-analysis of randomized controlled trials

Background

Multiple sclerosis is an inflammatory and neurodegenerative disease. People with multiple sclerosis (pwMS) experience chronic fatigue which is difficult to deal with therapeutically and greatly affects health-related quality of life (QOL).

PwMS are aware of the lack of generalized dietary advice related to their disease, leading to self-experimentation with diet.

It is necessary to provide objective information about dietary interventions for pwMS. We aim to provide an objective synthesis of the evidence for efficacy and safety of specific diets in pwMS through a rapid review and meta-analyses of randomized controlled trials (RCTs), examining symptomatic fatigue (MFIS), QOL, Expanded-Disability-Status-Scale (EDSS), and severe adverse events.

Methods

We have carried out a rapid review (MEDLINE and EMBASE) up to December 2021, with PRISMA methodology, and meta-analyses, of (RCTs). All statistical analyses were performed using the comprehensive meta-analysis (CMA) -RStudio 4.1.3. The analysis used weighted mean differences (WMD) and a 95% confidence interval (CI) using a random-effects model to compare the effects of the dietary intervention with the control.

Results

Eight studies met the inclusion criteria. Of these eight studies, five analyzed EDSS, three MFIS, and three QOL. A total of 515 patients were analyzed. These meta-analyses cumulative evidence support that dietary intervention is associated with a trend of reduction in fatigue (308 patients studied) -the difference between means (SMD) of the control group and intervention group was -2,033, 95%-IC (-3,195, -0,152), a p-value of 0.0341)-, an increase in QOL (77 patients studied), no significant effect on EDSS (337 patients studied), and no severe adverse events.

Conclusions

It is difficult to reach a high level of evidence in dietary studies. Our findings show that dietary intervention is associated with a trend of reduction in fatigue in MS. Taking into account the potential of dietary interventions and the benefit/risk ratio in their favor, neurologists must be aware of the great importance of making interventions on diet in MS if necessary. There are dietary interventions with some evidence of benefit for patients with MS, which could be chosen based on adherence, patient preferences, and individual outcomes. Large prospective clinical trials are needed to shed further light on this topic.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02913-w.

Current status and new developments in sphingosine-1-phosphate receptor antagonism: fingolimod and more

INTRODUCTION

Fingolimod was the first oral disease-modifying treatment approved for relapsing-remitting multiple sclerosis (MS) that serves as a sphingosine-1-phosphate receptor (S1PR) agonist. The efficacy is primarily mediated by S1PR subtype 1 activation, leading to agonist-induced down-modulation of receptor expression and further functional antagonism, blocking the egression of auto-aggressive lymphocytes from the lymph nodes in the peripheral compartment. The role of S1P signaling in the regulation of other pathways in human organisms through different S1PR subtypes has received much attention due to its immune-modulatory function and its significance for the regeneration of the central nervous system (CNS). The more selective second-generation S1PR modulators have improved safety and tolerability profiles.

AREAS COVERED

This review has been carried out based on current data on S1PR modulators, emphasizing the benefits of recent advances in this emergent class of immunomodulatory treatment for MS.

EXPERT OPINION

Ongoing clinical research suggests that S1PR modulators represent an alternative to first-line therapies in selected cases of MS. A better understanding of the relevance of selective S1PR pathways and the ambition to optimize selective modulation has improved the safety and tolerability of S1PR modulators in MS therapy and opened new perspectives for the treatment of other diseases.

Association Between Inflammatory Bowel Disease and Dementia: A Longitudinal Cohort Study

BACKGROUND

The association between inflammatory bowel disease (IBD) and dementia remains uncertain. We aim to investigate whether IBD is associated with higher dementia risk.

METHODS

Using multivariable Cox regression models, we analyzed the onset of all-cause dementia among 497,775 participants, including 5778 IBD patients in the UK Biobank as primary analysis. In secondary analysis, we further examined the difference in brain structure and cognitive function changes between IBD and non-IBD individuals. The diagnosis of IBD and dementia was confirmed with combination of primary care data, hospital inpatient data, death registry, and self-report data. Brain structure was measured by brain MRI as anatomic and tissue-specific volumes; cognitive function was tested in terms of reaction, visual episodic memory, verbal-numerical reasoning, and prospective memory.

RESULTS

During a mean follow-up of 11.58 years, 100 and 6709 incident all-cause dementia with or without IBD were documented, respectively. In multivariable Cox regression model, hazard ratio for incident dementia among IBD patients was 1.14 (95% confidence interval [CI], 0.94-1.39; P=.182) comparing with non-IBD participants; no statistically significant difference was observed in their brain MRI measures of anatomic and tissue-specific volumes, whereas IBD patients had a significantly increased reaction time (β=12.32; 95% CI, 1.97, 22.67; P = .020). Results of subgroup and sensitivity analyses were consistent with the main analysis.

CONCLUSIONS

Our study does not support a significant association between IBD and dementia. Further studies with better design and longer follow-up are needed to elucidate the association.

Drug-related immune-mediated myelopathies

Iatrogenic immune-mediated inflammatory disorders of the spinal cord are an uncommon but potentially severe complication of drug therapy for several human diseases. Particularly the introduction of novel biological agents in the treatment of systemic inflammatory disorders and cancer immunotherapy have led to a significant increase in immune-related adverse events of the central nervous system (CNS). The use of Tumor necrosis factor alpha (TNF-alpha) inhibitors in rheumatic and inflammatory bowel diseases has been associated with demyelinating and other inflammatory CNS conditions, including myelitis. The introduction of immune checkpoint inhibitors in the treatment of several human malignancies has led to an increase in drug-induced immune-related adverse events including in the CNS. Other drugs that have been associated with immune-mediated myelitis include tyrosine-kinase inhibitors and chimeric antigen receptor (CAR) T Cell therapy. A high degree of suspicion is necessary when diagnosing these conditions, as early diagnosis and treatment is crucial in preventing further neurological damage and disability. The treatment of drug-induced inflammatory myelitis typically involves administration of high-dose intravenous corticosteroids, however additional immunosuppressive agents may be required in severe or refractory cases. While most cases are monophasic and remit following discontinuation of the offending agent, chronic immunosuppressive therapy may be indicated in cases with a progressive or relapsing disease course or when a diagnosis of a specific underlying neuro-inflammatory disorder is made. Outcomes are generally favorable, however depend on the specific therapeutic agent used, the clinical presentation and patient factors. In this review we aim to describe the clinical characteristics, imaging findings and management for the most common forms of iatrogenic immune-mediated myelopathies.

Similar Time Trends of Hodgkin Lymphoma, Multiple Sclerosis, and Inflammatory Bowel Disease

BACKGROUND

The Epstein-Barr virus (EBV) plays a role in the causation of Hodgkin lymphoma (HL) and multiple sclerosis (MS). A previous study showed that the time trends of mortality from Crohn's disease (CD) and MS shared striking similarities. It was hypothesized that such similarities would also involve the time trends of ulcerative colitis and HL.

AIMS

To compare the time trends of CD and UC with those of HL and MS in 6 different countries.

METHODS

Using the vital statistics of England, Canada, Netherlands, Scotland, Switzerland, and United States from 1951 to 2020, the time trends of mortality from these 4 diseases were compared. The time-dependent changes of death rates were subjected to a birth-cohort analysis.

RESULTS

Similar trends were observed in all 6 countries. UC mortality rose among generations born during the nineteenth century and decreased among all generations born subsequently during the twentieth century. CD mortality was similarly characterized by a birth-cohort pattern with a rise and fall that were shifted by 20-30 years towards more recent generations when compared to UC. The birth-cohort pattern of UC was matched by a similar pattern of HL, whereas the birth-cohort pattern of CD was matched by a similar pattern of MS.

CONCLUSIONS

The similarities in the ubiquitous birth-cohort patterns of UC, CD, HL, and MS suggest that these 4 diseases share a common environmental risk factor. Such risk factor may be linked to EBV or its acquisition during an early period of a patient's lifetime.

Are neurodegenerative diseases associated with an increased risk of inflammatory bowel disease? A two-sample Mendelian randomization study

Background

Several studies have shown that neurodegenerative diseases (e.g., Parkinson’s disease [PD] and Alzheimer’s disease [AD]) are associated with inflammatory bowel disease (IBD), but the causality and direction of their associations remain unclear. Mendelian randomization (MR) studies have explored the causal effects of IBD on PD and AD. However, only a few studies examined this reverse association. Thus, this study aimed to explore whether there are causal associations of genetically predicted PD and AD with IBD, using a two-sample MR study.

Methods

Summary statistics for IBD, ulcerative colitis (UC), and Crohn’s disease (CD) were derived from a genome-wide association study (GWAS) meta-analysis, which included the International IBD Genetics Consortium and the UK IBD Genetics Consortium (n=59,957). Genetic variants associated with the largest meta-analysis of GWAS of PD (n=1,474,097) and AD (n=455,258) were used as instrumental variables. We used multiple methods, including inverse variance weighted (IVW), weighted median (WM), MR-Egger regression, weighted mode, and Robust Adjusted Profile Score (RAPS) methods, to estimate the effects of genetically predicted PD and AD on IBD. To confirm the validity of the analysis, we also evaluated the pleiotropic effects, heterogeneity, and leave-one-out sensitivity analysis that drive causal associations.

Results

The results of the IVW method, WM, and RAPS showed that genetically predicted PD was significantly associated with an increased risk of UC (odds ratio [OR]IVW=1.068, ORWM=1.107, ORRAPS=1.069, all P<0.05). Additionally, we found that there were significant associations of genetically predicted PD with CD (ORIVW=1.064, ORRAPS=1.065, all P<0.05) and IBD (ORIVW=1.062, ORRAPS=1.063, all P<0.05) using the IVW method and RAPS. However, there was no significant causal evidence of genetically predicted AD in IBD, UC, or CD among all MR methods. In all MR analyses, there were no horizontal pleiotropy (all P>0.05), or statistical heterogeneity. The sensitivity analysis results of the leave-one-out sensitivity analysis showed that the causal effect estimations of genetically predicted PD and AD on IBD were robust.

Conclusions

Our MR study corroborated a causal association between genetically predicted PD and IBD but did not support a causal effect of genetically predicted AD on IBD. More animal experiments or population-based observational studies are required to clarify the underlying mechanisms of PD and IBD.

Risk of dementia in patients with inflammatory bowel disease: a Danish population-based study

BACKGROUND

Inflammatory bowel disease (IBD) may be associated with increased dementia risk, but the literature is conflicting.

AIM

To investigate dementia risk in patients with IBD.

METHODS

We conducted a nationwide population-based cohort study in Denmark (1977-2018) including all patients with incident IBD matched with up to 10 general population comparators without IBD by sex, year of birth and region of residence. We calculated cumulative incidence proportions (CIPs) of dementia treating death as a competing risk, and adjusted hazard ratios (HRs) comparing IBD patients with matched comparisons. In a nested case-control analysis, we investigated the impact of IBD severity, steroid use, colorectal and small bowel surgery, and healthcare system contacts on dementia risk.

RESULTS

Of 88,985 patients with IBD (69.6% with ulcerative colitis [UC], 30.4% with Crohn's disease [CD]) and 884,108 comparisons, 2076 patients (78.1% with UC) and 23,011 comparisons (76.6% UC comparisons) developed dementia. The 40-year CIP of all-cause dementia was 7.2% for UC patients and 5.8% for CD patients. UC patients had a slightly increased HR of all-cause dementia (HR = 1.07 [95% confidence interval (CI): 1.01;1.12]) and Alzheimer's disease (HR = 1.10 [95% CI: 1.01-1.19]). CD patients had an increased HR of all-cause dementia (HR = 1.15 [95% CI: 1.05-1.27]) and frontotemporal dementia (HR = 2.70 [95% CI: 1.44-5.05]). Dementia in IBD patients was associated with frequent healthcare system contacts.

CONCLUSIONS

UC and CD are associated with slightly increased all-cause dementia risk, particularly frontotemporal dementia in CD patients. Frequent healthcare system contacts by patients with IBD and detection bias may play a role in the association.

Treatment of Inflammatory Bowel Disease and Pediatric Onset Multiple Sclerosis With Ocrelizumab and Ustekinumab in a JC-virus Positive Adolescent

Inflammatory bowel disease (IBD) and multiple sclerosis (MS) are known to co-occur. Many disease modifying therapies for MS may exacerbate IBD and several carry risk of progressive multifocal leukoencephalopathy in JC-virus (JCV) positive patients. Some biologics used for IBD can exacerbate MS. These factors make comanagement of these diseases difficult. We report a 17-year-old female who presented with right leg weakness and paresthesia and was diagnosed with pediatric onset MS (POMS). She then had worsening abdominal pain and diarrhea, accompanied by weight loss, and was subsequently diagnosed with Crohn's disease. She was weakly JCV positive, so a short trial of natalizumab was initiated, which controlled her POMS well but not her IBD. Ustekinumab and ocrelizumab were initiated and achieved remission of both diseases. In the absence of established treatment guidelines, we recommend considering this combination of therapies for cases where standard treatment modalities are not viable options.

Inflammatory bowel disease and immune-mediated inflammatory diseases: looking at the less frequent associations

Patients with inflammatory bowel disease (IBD) often have other immune-mediated inflammatory diseases (IMIDs), and the prevalence of any IMID is higher in IBD patients than in the general population. IBD and other IMIDs involve alterations in innate and adaptive immune responses. Their co-occurrence depends on shared immune and inflammatory processes, pathogenic mechanisms, and genetic and environmental risk factors, including drugs, especially tumor necrosis factor inhibitors. The more common IMIDs associated with IBD have been widely described, so this review focuses on the less frequent associations. The IMIDs discussed here are skin disorders (psoriasis, atopic dermatitis, vitiligo, epidermolysis bullosa acquisita, cutaneous polyarteritis nodosa, and hidradenitis suppurativa), hepato-pancreatic diseases (autoimmune hepatitis, granulomatous hepatitis, and autoimmune pancreatitis), endocrine diseases (autoimmune thyroid diseases, and type 1 diabetes mellitus), multiple sclerosis, and respiratory diseases (asthma, bronchiectasis, and interstitial pneumonia). The early detection of IMIDs in IBD patients is important to prevent their deleterious clinical course and limit their psychological impact. Care for IBD patients with IMIDs should be multispecialist, with a single therapeutic strategy instead of treating each disease separately.

Plasma concentrations of perfluoroalkyl substances and risk of inflammatory bowel diseases in women: A nested case control analysis in the Nurses' Health Study cohorts

BACKGROUND

Perfluoroalkyl substances (PFASs) are synthetic compounds used in a wide variety of industrial and consumer applications. An association between PFAS exposure and risk of ulcerative colitis (UC) has been reported in a highly exposed population. However, data are limited on risk of inflammatory bowel diseases (IBD) among individuals with background population levels of PFAS exposure.

OBJECTIVES

We set out to examine the association between plasma PFAS concentrations and risk of IBD among women in two population-based, prospective cohort studies in which pre-diagnostic blood specimens were available.

METHODS

We conducted a nested case-control study in the Nurses' Health Study and Nurses' Health Study II cohorts. We identified 73 participants with incident Crohn's disease (CD) and 80 participants with incident UC who had provided blood samples before diagnosis. Cases were matched 1:2 to IBD-free controls. Plasma concentrations of five major PFASs were measured by liquid chromatography and tandem mass spectrometry. We used conditional logistic models to estimated odds ratios for risk of IBD according to log10-transformed PFAS concentrations, adjusting for potential confounders.

RESULTS

In multivariable models, we observed inverse associations between plasma concentrations of three PFASs and risk of CD (all P ≤ 0.012 for a standard deviation increase in log10PFAS). The inverse association with CD was strongest for perfluorodecanoate, where, compared to the lowest tertile, the odds ratio (OR) for the highest tertile was 0.39 (95% confidence interval, 0.17-0.92). No associations were observed between PFAS concentrations and UC risk.

DISCUSSION

Our results do not support the hypothesis that elevated PFAS exposure is associated with higher risk of UC. Contrary to expectation, our data suggest that circulating concentrations of some PFASs may be inversely associated with CD development.

A systematic review and functional bioinformatics analysis of genes associated with Crohn's disease identify more than 120 related genes

BACKGROUND

Crohn's disease is one of the two categories of inflammatory bowel diseases that affect the gastrointestinal tract. The heritability estimate has been reported to be 0.75. Several genes linked to Crohn's disease risk have been identified using a plethora of strategies such as linkage-based studies, candidate gene association studies, and lately through genome-wide association studies (GWAS). Nevertheless, to our knowledge, a compendium of all the genes that have been associated with CD is lacking.

METHODS

We conducted functional analyses of a gene set generated from a systematic review where genes potentially related to CD found in the literature were analyzed and classified depending on the genetic evidence reported and putative biological function. For this, we retrieved and analyzed 2496 abstracts comprising 1067 human genes plus 22 publications regarding 133 genes from GWAS Catalog. Then, each gene was curated and categorized according to the type of evidence associated with Crohn's disease.

RESULTS

We identified 126 genes associated with Crohn's disease risk by specific experiments. Additionally, 71 genes were recognized associated through GWAS alone, 18 to treatment response, 41 to disease complications, and 81 to related diseases. Bioinformatic analysis of the 126 genes supports their importance in Crohn's disease and highlights genes associated with specific aspects such as symptoms, drugs, and comorbidities. Importantly, most genes were not included in commercial genetic panels suggesting that Crohn's disease is genetically underdiagnosed.

CONCLUSIONS

We identified a total of 126 genes from PubMed and 71 from GWAS that showed evidence of association to diagnosis, 18 to treatment response, and 41 to disease complications in Crohn's disease. This prioritized gene catalog can be explored at http://victortrevino.bioinformatics.mx/CrohnDisease .

Multiple sclerosis and inflammatory bowel disease: A systematic review and meta-analysis

BACKGROUND

Multiple sclerosis (MS) and inflammatory bowel disease (IBD) are two autoimmune diseases that seriously affect patients' quality of life. Previous studies have established an association between MS and IBD, including Crohn's disease (CD) and ulcerative colitis (UC), but the results were inconsistent. The aim of this study was to quantify the prevalences of and the association between MS and IBD.

METHODS

The PubMed, Web of Science, and Embase databases were searched through November 2020 for studies reporting data on MS among patients with IBD and vice versa. The main outcomes were the proportion of MS in patients with IBD and vice versa, as well as the association (risk ratio [RR]) of IBD in MS and that of MS in IBD.

RESULTS

Based on the analysis of 17 studies, the prevalence of MS in patients with IBD was 0.2% (95% CI 0.1-0.4%), while the prevalence of IBD in patients with MS was 0.6% (95% CI 0.4-0.9%). Patients with MS had a higher prevalence of IBD than controls (RR = 1.53, 95% CI 1.38-1.70, p < 0.00001). There was a similarly high risk of developing CD (RR 1.41, 95% CI 1.14-1.74, p = 0.001) or UC (RR 1.42, 95% CI 1.17-1.71, p = 0.0003) in patients with MS (p for subgroup differences: 0.97). Patients with IBD had a higher prevalence of MS than controls (RR = 1.91, 95% CI 1.06-3.45, p = 0.03).

CONCLUSIONS

Clinicians should be aware of the increased risk of IBD or MS comorbidity during the diagnostic process. Systematic diagnosis and management at an earlier stage are suggested.

Impact of intestinal disorders on central and peripheral nervous system diseases

Brain injuries and neurological diseases have a significant impact on the gut microbiome and the gut barrier. Reciprocally, gut disorders, such as Inflammatory Bowel Syndromes (IBS), can affect the development and pathology of neurodegenerative and neuropsychiatric diseases, although this aspect is less well studied and is the focus of this review. Inflammatory Bowel Syndrome (IBS) is a chronic and debilitating functional gastrointestinal disorder afflicting an estimated 9-23% of the world's population. A hallmark of this disease is leaky gut, a pathology in which the integrity of the gut blood barrier is compromised, causing gut contents such as immune cells and microbiota to enter the bloodstream leading to low-grade systemic inflammation. The increased levels of inflammation associated cytokines in circulation has the potential to affect all organs, including the brain. Although the brain is protected by the blood brain barrier, inflammation associated cytokines can damage the junctions in this barrier and allow brain infiltration of peripheral immune cells. Central inflammation in the brain is associated with various neurodegenerative disease such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and neuropsychiatric disorders, namely, depression, and anxiety. Neurodegenerative diseases are of particular concern due to the anticipated rise in the population of the elderly and consequently, the prevalence of these diseases. Additionally, depression and anxiety are the most common mental illnesses affecting roughly 18% of the American population. In this review, we will explore the mechanisms by which IBS can influence the risk and severity of neurological disease.

The Gut-Brain Axis in Multiple Sclerosis. Is Its Dysfunction a Pathological Trigger or a Consequence of the Disease?

A large and expending body of evidence indicates that the gut-brain axis likely plays a crucial role in neurological diseases, including multiple sclerosis (MS). As a whole, the gut-brain axis can be considered as a bi-directional multi-crosstalk pathway that governs the interaction between the gut microbiota and the organism. Perturbation in the commensal microbial population, referred to as dysbiosis, is frequently associated with an increased intestinal permeability, or "leaky gut", which allows the entrance of exogeneous molecules, in particular bacterial products and metabolites, that can disrupt tissue homeostasis and induce inflammation, promoting both local and systemic immune responses. An altered gut microbiota could therefore have significant repercussions not only on immune responses in the gut but also in distal effector immune sites such as the CNS. Indeed, the dysregulation of this bi-directional communication as a consequence of dysbiosis has been implicated as playing a possible role in the pathogenesis of neurological diseases. In multiple sclerosis (MS), the gut-brain axis is increasingly being considered as playing a crucial role in its pathogenesis, with a major focus on specific gut microbiota alterations associated with the disease. In both MS and its purported murine model, experimental autoimmune encephalomyelitis (EAE), gastrointestinal symptoms and/or an altered gut microbiota have been reported together with increased intestinal permeability. In both EAE and MS, specific components of the microbiota have been shown to modulate both effector and regulatory T-cell responses and therefore disease progression, and EAE experiments with germ-free and specific pathogen-free mice transferred with microbiota associated or not with disease have clearly demonstrated the possible role of the microbiota in disease pathogenesis and/or progression. Here, we review the evidence that can point to two possible consequences of the gut-brain axis dysfunction in MS and EAE: 1. A pro-inflammatory intestinal environment and "leaky" gut induced by dysbiosis could lead to an altered communication with the CNS through the cholinergic afferent fibers, thereby contributing to CNS inflammation and disease pathogenesis; and 2. Neuroinflammation affecting efferent cholinergic transmission could result in intestinal inflammation as disease progresses.

Investigating the shared genetic architecture between multiple sclerosis and inflammatory bowel diseases

An epidemiological association between multiple sclerosis (MS) and inflammatory bowel disease (IBD) is well established, but whether this reflects a shared genetic aetiology, and whether consistent genetic relationships exist between MS and the two predominant IBD subtypes, ulcerative colitis (UC) and Crohn’s disease (CD), remains unclear. Here, we use large-scale genome-wide association study summary data to investigate the shared genetic architecture between MS and IBD overall and UC and CD independently. We find a significantly greater genetic correlation between MS and UC than between MS and CD, and identify three SNPs shared between MS and IBD (rs13428812), UC (rs116555563) and CD (rs13428812, rs9977672) in cross-trait meta-analyses. We find suggestive evidence for a causal effect of MS on UC and IBD using Mendelian randomization, but no or weak and inconsistent evidence for a causal effect of IBD or UC on MS. We observe largely consistent patterns of tissue-specific heritability enrichment for MS and IBDs in lung, spleen, whole blood and small intestine, and identify cell-type-specific enrichment for MS and IBDs in CD4⁺ T cells in lung and CD8⁺ cytotoxic T cells in lung and spleen. Our study sheds light on the biological basis of comorbidity between MS and IBD.

An epidemiological association between multiple sclerosis (MS) and inflammatory bowel disease (IBD) is well-established, but a genetic link is unclear. Here, the authors investigate the shared genetic architecture between MS and IBD to shed light on the biological basis of comorbidity.

The Gut-Brain Axis in Inflammatory Bowel Disease-Current and Future Perspectives

The gut–brain axis is a bidirectional communication system driven by neural, hormonal, metabolic, immunological, and microbial signals. Signaling events from the gut can modulate brain function and recent evidence suggests that the gut–brain axis may play a pivotal role in linking gastrointestinal and neurological diseases. Accordingly, accumulating evidence has suggested a link between inflammatory bowel diseases (IBDs) and neurodegenerative, as well as neuroinflammatory diseases. In this context, clinical, epidemiological and experimental data have demonstrated that IBD predisposes a person to pathologies of the central nervous system (CNS). Likewise, a number of neurological disorders are associated with changes in the intestinal environment, which are indicative for disease-mediated gut–brain inter-organ communication. Although this axis was identified more than 20 years ago, the sequence of events and underlying molecular mechanisms are poorly defined. The emergence of precision medicine has uncovered the need to take into account non-intestinal symptoms in the context of IBD that could offer the opportunity to tailor therapies to individual patients. The aim of this review is to highlight recent findings supporting the clinical and biological link between the gut and brain, as well as its clinical significance for IBD as well as neurodegeneration and neuroinflammation. Finally, we focus on novel human-specific preclinical models that will help uncover disease mechanisms to better understand and modulate the function of this complex system.

Onset Symptom Clusters in Multiple Sclerosis: Characteristics, Comorbidities, and Risk Factors

Background: Multiple sclerosis (MS) symptoms are expected to aggregate in specific patterns across different stages of the disease. Here, we studied the clustering of onset symptoms and examined their characteristics, comorbidity patterns and associations with potential risk factors.

Methods: Data stem from the Swiss Multiple Sclerosis Registry, a prospective study including 2,063 participants by November 2019. MS onset symptoms were clustered using latent class analysis (LCA). The latent classes were further examined using information on socio-demographic characteristics, MS-related features, potential risk factors, and comorbid diseases.

Results: The LCA model with six classes (frequencies ranging from 12 to 24%) was selected for further analyses. The latent classes comprised a multiple symptoms class with high probabilities across several symptoms, contrasting with two classes with solitary onset symptoms: vision problems and paresthesia. Two gait classes emerged between these extremes: the gait-balance class and the gait-paralysis class. The last class was the fatigue-weakness-class, also accompanied by depression symptoms, memory, and gastro-intestinal problems. There was a moderate variation by sex and by MS types. The multiple symptoms class yielded increased comorbidity with other autoimmune disorders. Similar to the fatigue-weakness class, the multiple symptoms class showed associations with angina, skin diseases, migraine, and lifetime prevalence of smoking. Mononucleosis was more frequently reported in the fatigue-weakness and the paresthesia class. Familial aggregation did not differ among the classes.

Conclusions: Clustering of MS onset symptoms provides new perspectives on the heterogeneity of MS. The clusters comprise different potential risk factors and comorbidities. They point toward different risk mechanisms.

Use of anti-TNF-α therapy in Crohn's disease is associated with increased incidence of multiple sclerosis

OBJECTIVE

We investigated if anti-tumor necrosis factor-α (anti-TNF-α) drugs used in the treatment of inflammatory bowel disease (IBD) alter the incidence of MS and if so, to understand the magnitude of such an effect.

METHODS

This is a retrospective cohort study of data from Truven Health Market Scan administrative claims database. The patients included in the study had to be ≥ 18 years of age. The presence of IBD was based on at least 2 claims of International Classification of Diseases (ICD-9 or 10) diagnosis codes. The IBD diagnosis index date had to precede the MS diagnosis index date for inclusion in the study. The diagnosis of multiple sclerosis (MS) was defined as having at least 2 claims for the disease (ICD 9, 340 and ICD 10 codes, G35) and at least one prescription claim for any of the drugs that were defined as MS therapy.

RESULTS

Patients with IBD had 1.32 times the risk of MS incidence compared to healthy controls (adjusted incidence rate ratio (IRR): 1.32; 95% CI: 1.03 - 1.71; p = .0312). Patients with IBD exposed to anti-TNF-α therapies had a 43% increase in the incidence of MS compared to those with IBD without exposure (adjusted incidence rate: 1.43; 95% CI: .062 - 3.32; p = .3989). Among CD patients treated anti-TNF-α medications an increase in the incidence of MS, compared to CD patients not exposed to such medications was observed (IRR = 2.62; 95% CI: 1.00 to 6.83; p = 0.049), statistically significant. After adjusting for age/gender, patients with CD using anti-TNF-α agents had an increase of incidence in MS (adjusted IRR: 2.24; 95% CI: 0.85 - 5.94; p = .1035) but it was not statistically significant.

CONCLUSIONS

Use of anti-TNF-α drugs in CD was associated with a statistically significant increase in the incidence of MS but this effect was lost when controlled for age/gender.

Association Between Tumor Necrosis Factor Inhibitor Exposure and Inflammatory Central Nervous System Events

Question

Is exposure to tumor necrosis factor inhibitors associated with risk of inflammatory demyelinating and nondemyelinating central nervous system events in patients with an autoimmune disease?

Findings

In this case-control study of 212 patients with or without inflammatory CNS events, exposure to tumor necrosis factor inhibitors was associated with an increased risk of inflammatory central nervous system events. The association was similar for both inflammatory demyelinating and nondemyelinating central nervous system events.

Meaning

The association observed between exposure to tumor necrosis factor inhibitor and increased risk of inflammatory demyelinating and nondemyelinating central nervous system events warrants future research to ascertain whether the association may indicate de novo inflammation or exacerbation of already aberrant inflammatory pathways.

Importance

Tumor necrosis factor (TNF) inhibitors are common therapies for certain autoimmune diseases, such as rheumatoid arthritis. An association between TNF inhibitor exposure and inflammatory central nervous system (CNS) events has been postulated but is poorly understood.

Objective

To evaluate whether TNF inhibitor exposure is associated with inflammatory demyelinating and nondemyelinating CNS events in patients with an indication for TNF inhibitor use and to describe the spectrum of those CNS events.

Design, Setting, and Participants

A nested case-control study was conducted using the medical records of patients with autoimmune diseases treated at 3 Mayo Clinic locations (Rochester, Minnesota; Scottsdale, Arizona; and Jacksonville, Florida) between January 1, 2003, and February 20, 2019. Patients were included if their records reported International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, diagnostic codes for US Food and Drug Administration–approved autoimmune disease indication for TNF inhibitor use (ie, rheumatoid arthritis, ankylosing spondylitis, psoriasis and psoriatic arthritis, Crohn disease, and ulcerative colitis) and diagnostic codes for inflammatory CNS events of interest. Patients were matched 1:1 with control participants by year of birth, type of autoimmune disease, and sex.

Exposures

TNF inhibitor exposure data were derived from the medical records along with type of TNF inhibitor, cumulative duration of exposure, and time of exposure.

Main Outcomes and Measures

The main outcome was either inflammatory demyelinating (multiple sclerosis and other diseases such as optic neuritis) or nondemyelinating (meningitis, meningoencephalitis, encephalitis, neurosarcoidosis, and CNS vasculitis) CNS event. Association with TNF inhibitor was evaluated with conditional logistic regression and adjusted for disease duration to determine the odds ratios (ORs) and 95% CIs. Secondary analyses included stratification of outcome by inflammatory demyelinating and nondemyelinating CNS events and by autoimmune disease (rheumatoid arthritis and non–rheumatoid arthritis).

Results

A total of 212 individuals were included: 106 patients with inflammatory CNS events and 106 control participants without such events. Of this total, 136 were female (64%); the median (interquartile range) age at disease onset for patients was 52 (43-62) years. Exposure to TNF inhibitors occurred in 64 patients (60%) and 42 control participants (40%) and was associated with an increased risk of any inflammatory CNS event (adjusted OR, 3.01; 95% CI, 1.55-5.82; P = .001). These results were similar when the outcome was stratified by demyelinating and nondemyelinating CNS events. Secondary analyses found the association was predominantly observed in patients with rheumatoid arthritis (adjusted OR, 4.82; 95% CI, 1.62-14.36; P = .005).

Conclusions and Relevance

This study found that exposure to TNF inhibitors in patients with autoimmune diseases appeared to be associated with increased risk for inflammatory CNS events. Whether this association represents de novo or exacerbated inflammatory pathways requires further research.

Neurology of inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions affecting the digestive system, comprising two main distinctive entities, ulcerative colitis (UC) and Crohn's disease (CD). Besides gastrointestinal manifestations, IBD causes extraintestinal manifestations in the central and peripheral nervous system. The incidence of neurological complications in IBD ranges from 0.25% to 47.5%. The pathophysiology of neurological manifestations of IBD is mostly immune mediated, but dysfunction of the brain-gut axis, arterial and venous thromboembolism, infections, nutritional deficiencies and side-effects of medications (steroids, metronidazole, sulfasalazine, anti-TNF-α, anti-integrin antibodies) are other contributory mechanisms. Patients with IBD have an increased risk of arterial and venous stroke, mainly during periods of exacerbations. Vasculitis is extremely rare. There is a bidirectional association between multiple sclerosis and IBD, with a relative risk for comorbidity of 1.54, being 1.53 for the risk of multiple sclerosis in IBD and 1.55 for the risk of IBD in multiple sclerosis patients. Anti-TNF-α therapy is contraindicated in the treatment of patients who have both IBD and multiple sclerosis. Demyelinating disorders can also be a rare complication of anti-TNF-α therapy. Optic neuritis, transverse myelitis, progressive myelopathy, central nervous system infections, epilepsy and encephalopathy are among other uncommon neurological complications. Peripheral nervous system manifestations include peripheral neuropathy, either demyelination and axonal, myasthenia gravis and polymyositis/dermatomyositis and localized forms of myositis.

Defining the disease course of TNFα blockers-associated Multiple Sclerosis

Tumour Necrosis Factor alpha (TNFα) blockers are common and effective treatments for several autoimmune diseases but can be associated with neuroinflammatory events. We describe the disease course of ten patients who developed CNS demyelinating events while exposed to TNFα blockers. We divided them into two groups: eight patients with Relapsing Multiple Sclerosis and two isolated optic neuritis. In our cohort, TNFα blockers-associated Multiple Sclerosis does not seem to be associated with a more aggressive course and can be managed with MS-specific DMTs, chosen considering the clinical course and the concomitant autoimmune disease. Our findings need confirmation in larger cohorts to further characterize the disease course of TNFα blockers-associated Multiple Sclerosis.

Multiple sclerosis and aging: comorbidity and treatment challenges

BACKGROUND

The prevalence of elderly patients with MS is increasing, in conjunction with the ageing general population. This review will examine the principal characteristics of elderly patients with MS and how the concomitant pathologies affect them. Finally, it will assess the impact of the medications on these patients and whether it would be safe to discontinue the disease-modifying treatment.

METHODS

Searches using PubMed were conducted in October 2020 to collect studies assessing the impact of age and comorbidities on patients with MS.

RESULTS

Several studies showed that aged patients develop concomitant pathologies that could worsen the disease's prognosis. Also, MS itself may be closely related to cognitive impairment, even though the exact etiopathogenic mechanism of it is still unclear. To date, safety and efficacy of currently available drugs remain unassessed in elderly populations. These treatments may not be beneficial in preventing the progression of disability in ageing people with no signs of inflammatory activity, and discontinuation of treatment is often discussed in this subgroup of patients.

CONCLUSIONS

The presence of cardiovascular pathology, psychiatric disorders, diabetes or cancer is further associated with increased mortality in MS patients. The diagnosis and treatment of the disease is challenged by both age-related comorbidities and clinical variations compared to younger patients. It may be safe to discontinue treatment in elderly patients with no clinico-radiological activity.

Comorbidity in multiple sclerosis patients from Nordland County, Norway - validated data from the Norwegian Patient Registry

BACKGROUND

Knowledge of comorbid disorders is important to optimize therapy for multiple sclerosis (MS), but data are limited. The aim of this study was to assess comorbidity in persons with MS living in Nordland County on January 1, 2017.

METHODS

Data were retrieved from the Norwegian Patient Registry (2008-2017) and validated through review of electronic hospital charts (1970-2017). Comorbidity was defined as any distinct disorder, classified in the International Classification of Diseases (ICD-10), that had existed or occurred after the diagnosis of MS was established.

RESULTS

Data from 637 subjects were reviewed, and 97.5% were registered with at least one comorbid condition. Malignant melanoma was found in 0.5%, and non-melanoma skin cancers in 1.9%. In female subjects, breast cancer was found in 3.3%. Hypothyroidism was confirmed in 3.1%, type-1 diabetes in 0.3%, type-2 diabetes in 3.9%, psychosis in 0.6%, epilepsy in 2.8%, myocardial infarction in 1.7%, subarachnoid hemorrhage in 0.2%, cerebral infarction in 0.6%, pulmonary embolism in 0.9%, inflammatory bowel disease in 1.3%, and rheumatoid arthritis in 0.6%.

CONCLUSION

Compared to reports from other Norwegian epidemiological studies, a higher proportion of inflammatory bowel disease and epilepsy was found. This is in accordance with findings from other studies. The prevalence of non-melanoma skin cancers was significantly higher than in the general Norwegian population as they were reported by The Cancer Registry of Norway.

Maternal diabetes and risk of multiple sclerosis in the offspring: A Danish nationwide register-based cohort study

BACKGROUND

Previous studies suggest a 3- to-10-fold increased risk of multiple sclerosis (MS) in offspring of mothers with diabetes mellitus (DM).

OBJECTIVES

To examine MS risk in offspring of diabetic mothers, overall and according to type of maternal DM, that is, pregestational DM or gestational DM, as well as to examine MS risk among offspring of diabetic fathers.

METHODS

The study cohort included all 1,633,436 singletons born in Denmark between 1978 and 2008. MS diagnoses were identified in the Danish Multiple Sclerosis Registry, and parental DM diagnoses in the National Patient Register. We used Cox proportional hazards regression analyses to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for the association of parental DM with MS risk in the offspring.

RESULTS

MS risk among individuals whose mothers had pregestational DM was 2.3-fold increased compared with that among individuals with nondiabetic mothers (HR = 2.25; 95% CI: 1.35-3.75, n = 15). MS risk was statistically non-significant among offspring of mothers with gestational DM (HR = 1.03 (95% CI: 0.49-2.16), n = 7) and among offspring of diabetic fathers (HR = 1.40 (95% CI: 0.78-2.54), n = 11).

CONCLUSION

Our nationwide cohort study utilizing high-quality register data in Denmark over several decades corroborates the view that offspring of diabetic mothers may be at an elevated risk of developing MS.

Inflammatory colitis associated with Teriflunomide

Teriflunomide is an oral disease modifying therapy for relapsing-remitting multiple sclerosis (RRMS). Gastrointestinal (GI) side effects occurred in 15-17.9% of patients in the clinical trials and usually were mild and self-limiting. Few cases of inflammatory colitis related to teriflunomide and leflunomide, a prodrug which converts to teriflunomide and is used in the treatment of rheumatoid arthritis, have been reported but no clinical data is available except for a single case of lymphocytic colitis. We here report a 49-year-old man with RRMS who developed severe diarrhea and weight loss six months after starting teriflunomide and eventually was found to have multiple ulcers and inflammatory changes consistent with Crohn's disease. After stopping teriflunomide and chelation therapy, he was started on immunotherapy for Crohn's given the highly inflammatory degree of GI symptoms and histology findings.