Bowel symptoms predate the diagnosis among many patients with multiple sclerosis: A 14-year cohort study

Gastrointestinal conditions in the multiple sclerosis prodrome

OBJECTIVE

To investigate gastrointestinal (GI)-related physician visits and drug dispensations in the 5 years preceding a first recorded demyelinating event or multiple sclerosis (MS) onset.

METHODS

Using linked administrative and clinical data from British Columbia (1996-2013), Canada, we identified an administrative cohort via a validated algorithm (n = 6863), a clinical cohort diagnosed at a MS clinic (n = 966), and matched controls (administrative cohort: n = 31,865; clinical cohort: n = 4534). In each cohort, the 5 years before a first demyelinating event or MS symptom onset (i.e., index date) were examined. We compared rates of GI-related physician visits and risk of ≥1 GI-related dispensation between MS cases and controls using negative binomial and robust Poisson models. Sex differences were tested using interaction terms.

RESULTS

The administrative cohort MS cases had higher rates of physician visits related to gastritis and duodenitis (adjusted rate/risk ratio (aRR):1.42, 95% CI: 1.10-1.83) and diseases of the esophagus (aRR: 1.46, 95% CI: 1.06-2.02) prior to the index date. MS cases also had greater risk of at least one dispensation for several drug classes, including constipation-related (aRR: 1.82, 95% CI: 1.50-2.22), antiemetics/antinauseants (aRR: 1.64, 95% CI: 1.43-1.89), and propulsives (promotility drugs; aRR: 1.62, 95% CI: 1.47-1.79). Men had a disproportionally higher relative risk for propulsives than women (aRR: men = 2.32, 95% CI: 1.79-3.00; women = 1.54, 95% CI: 1.36-1.72). Several findings were similar in the smaller clinical cohort though none reached statistical significance.

INTERPRETATION

GI-related physician visits and drug dispensations were more common in the 5 years before the first demyelinating event versus matched controls. GI symptoms are a measurable feature of the prodromal or early phase of MS, with a sex difference evident.

A multiscale assessment of bowel impairment in an Italian multiple sclerosis cohort

Bowel dysfunctions (BD) in multiple sclerosis (MS) are under reported despite their clinical relevance. Scales usually applied do not thoroughly assess constipation and fecal incontinence. Instead, a proper qualitative and quantitative description of these symptoms might have relevant clinical and scientific consequences. The aim of this project is to study the prevalence of BD in a cohort of persons with MS (pwMS). Four-hundred and forty-seven pwMS (330 relapsing-remitting MS-RRMS and 117 progressive MS-PMS) were recruited. Three different questionnaires were administered: the neurogenic bowel dysfunction score (NBDS), the Wexner constipation scale (WexCon) and the Wexner incontinence scale (WexInc). All the scales were divided in subscores according to symptom severity. The prevalence of BD, considered as NBDS > 0, was 53.7%. Mean scores in pwMS group were as follows: NBDS 2.6 (SD 3.5), WexInc 1.1 (SD 2.4), WexCon 4.4 (SD 5.9). NBDS, WexCon and WexInc were significantly higher in PMS vs RRMS (p < 0.001), and significantly associated with disease duration, EDSS, multiple sclerosis severity score (p < 0.001), as well as with each other (p < 0.001). Our study confirms the presence of bowel dysfunctions in a large group of pwMS with a wide range of disability and their association with progressive disease phenotype and clinical disability.

Multiple sclerosis and bowel symptoms: Frequency and barriers to their management

BACKGROUND

The frequency of bowel symptoms (BSs) is still a matter for debate in multiple sclerosis (MS) patients. However, BSs have been shown to cause significant distress. Our study aimed to (i) investigate the frequency of BSs, particularly those that are not managed, (ii) identify potential predictors for help-seeking care for patients with BSs, and (iii) evaluate the ability of the Neurogenic Bowel Dysfunction (NBD) score to screen for BSs.

METHOD

Three hundred sixty-nine MS patients completed a cross-sectional demographic and clinical survey of MS and BSs and their management.

RESULTS

BSs were reported by 47.7% of MS patients. Eighty-eight percent of MS patients had a very minor-minor Neurogenic Bowel Disorder (NBD) score and 12% had a moderate-severe NBD score. Forty-one percent of patients did not report their BS to a healthcare provider, mainly because they preferred not to talk about the problem. BS duration was the only significant predictor of help-seeking for BS management. Female sex, visual impairment, a digestive history, and longer MS duration were good predictors of BSs. Patients with BSs (86%) were correctly identified with an NBD score >2.

CONCLUSION

BSs are under-detected in MS populations. This is partially related to non-declaration by patients. Targeting BSs using the NBD score is a good way to increase reporting.

Gastrointestinal Dysfunction in Multiple Sclerosis and Related Conditions

Nervous system disorders may be accompanied by gastrointestinal (GI) dysfunction. Brain lesions may be responsible for GI problems such as decreased peristalsis (e.g., lesions in the basal ganglia, pontine defecation center/Barrington's nucleus), decreased abdominal strain (e.g., lesions in the parabrachial nucleus), hiccupping and vomiting (e.g., lesions in the area postrema), and appetite loss (e.g., lesions in the hypothalamus). Decreased peristalsis also may be caused by lesions of the spinal long tracts or the intermediolateral nucleus projecting to the myenteric plexus. This review addresses GI dysfunction caused by multiple sclerosis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein-associated disorder. Neuro-associated GI dysfunction may develop concurrently with brain or spinal cord dysfunction or may predate it. Collaboration between gastroenterologists and neurologists is highly desirable when caring for patients with GI dysfunction related to nervous system disorders, particularly since patients with these symptoms may visit a gastroenterologist prior to the establishment of a neurological diagnosis.

Radiologically Isolated Syndrome and the Multiple Sclerosis Prodrome in Pediatrics: Early Features of the Spectrum of Demyelination

Radiologically isolated syndrome refers to the clinical scenario in which individuals have imaging concerning for multiple sclerosis and would otherwise satisfy radiographic dissemination in space criteria, but do not have any attributable signs or symptoms. Radiologically isolated syndrome has been increasingly recognized in the pediatric population and it is understood certain individuals will transition to a formal diagnosis of multiple sclerosis over time. This review aims to outline the available data within this unique population including the diagnostic criteria, epidemiology, risk factors associated with transitioning to multiple sclerosis, and the current therapeutic landscape. Radiologically isolated syndrome will also be positioned within a broader spectrum of demyelinating disease as recent data has pointed towards a likely prodromal phase that precedes a first clinical event and diagnosis of multiple sclerosis. Characterizing the radiographic features, clinical symptoms, and biomarkers that constitute this prodromal phase of multiple sclerosis would help identify patients who may most benefit from early intervention in the future.

Neurodegenerative and Neurodevelopmental Diseases and the Gut-Brain Axis: The Potential of Therapeutic Targeting of the Microbiome

The human gut microbiome contains the largest number of bacteria in the body and has the potential to greatly influence metabolism, not only locally but also systemically. There is an established link between a healthy, balanced, and diverse microbiome and overall health. When the gut microbiome becomes unbalanced (dysbiosis) through dietary changes, medication use, lifestyle choices, environmental factors, and ageing, this has a profound effect on our health and is linked to many diseases, including lifestyle diseases, metabolic diseases, inflammatory diseases, and neurological diseases. While this link in humans is largely an association of dysbiosis with disease, in animal models, a causative link can be demonstrated. The link between the gut and the brain is particularly important in maintaining brain health, with a strong association between dysbiosis in the gut and neurodegenerative and neurodevelopmental diseases. This link suggests not only that the gut microbiota composition can be used to make an early diagnosis of neurodegenerative and neurodevelopmental diseases but also that modifying the gut microbiome to influence the microbiome-gut-brain axis might present a therapeutic target for diseases that have proved intractable, with the aim of altering the trajectory of neurodegenerative and neurodevelopmental diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, autism spectrum disorder, and attention-deficit hyperactivity disorder, among others. There is also a microbiome-gut-brain link to other potentially reversible neurological diseases, such as migraine, post-operative cognitive dysfunction, and long COVID, which might be considered models of therapy for neurodegenerative disease. The role of traditional methods in altering the microbiome, as well as newer, more novel treatments such as faecal microbiome transplants and photobiomodulation, are discussed.

Heart rate variability and fatigue in MS: two parallel pathways representing disseminated inflammatory processes?

BACKGROUND

Fatigue is a disabling symptom of multiple sclerosis. Its biological causes are still poorly understood. Several years ago, we proposed that fatigue might be the subjective representation of inflammatory processes. An important step for a straight-forward evaluation of our model would be to show that the level of fatigue is associated with vagal activation. The heart rate is under partial control of the vagus nerve. Using power spectrum analysis allows to separate, at least partly, sympathetic and parasympathetic impact on heart rate variability.

METHODS

This narrative review summarizes the evidence for heart rate variability changes in MS patients, their relationship with fatigue and disease course. To do this, we conducted a literature search, including 45 articles relevant to the topic treated in this review.

RESULTS

We illustrate that (1) inflammation leads to a change in cardiac behavior during acute and chronic phases, both in animals and in humans; (2) MS patients show changes of heart rate variability (HRV) that resemble those during acute and chronic inflammation due to multiple causes; (3) existing evidence favors a set of specific predictions about fatigue and parallel HRV changes; and (4) that MS-related brainstem lesions or neurological impairments do not completely explain HRV changes, leaving enough place for an explanatory relation between HRV and fatigue.

DISCUSSION

We discuss the results of this review in relation to our model of fatigue and propose several observational and experimental studies that could be conducted to gain a better insight into whether fatigue and HRV can be interpreted as a common pathway, both reflecting activated autoimmune processes in MS patients.

Impact of Siponimod on Enteric and Central Nervous System Pathology in Late-Stage Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS). Although immune modulation and suppression are effective during relapsing-remitting MS, secondary progressive MS (SPMS) requires neuroregenerative therapeutic options that act on the CNS. The sphingosine-1-phosphate receptor modulator siponimod is the only approved drug for SPMS. In the pivotal trial, siponimod reduced disease progression and brain atrophy compared with placebo. The enteric nervous system (ENS) was recently identified as an additional autoimmune target in MS. We investigated the effects of siponimod on the ENS and CNS in the experimental autoimmune encephalomyelitis model of MS. Mice with late-stage disease were treated with siponimod, fingolimod, or sham. The clinical disease was monitored daily, and treatment success was verified using mass spectrometry and flow cytometry, which revealed peripheral lymphopenia in siponimod- and fingolimod-treated mice. We evaluated the mRNA expression, ultrastructure, and histopathology of the ENS and CNS. Single-cell RNA sequencing revealed an upregulation of proinflammatory genes in spinal cord astrocytes and ependymal cells in siponimod-treated mice. However, differences in CNS and ENS histopathology and ultrastructural pathology between the treatment groups were absent. Thus, our data suggest that siponimod and fingolimod act on the peripheral immune system and do not have pronounced direct neuroprotective effects.

Neurogenic Bowel Dysfunction Over the Course of Multiple Sclerosis: A Review

Neurogenic bowel dysfunction ranks as one of the most frequent problems experienced by people with multiple sclerosis (MS); it is one of the first symptoms to appear at disease onset and continues throughout the course of the disease. This review, based on literature searches of Medline and PubMed, examines bowel dysfunction causes and cofactors (ie, impaired mobility, fatigue, depression and anxiety, childbirth) that occur over the course of the disease. Coverage includes management of bowel dysfunction with noninvasive methods, including diet and fluid intake, together with pharmacologic treatments for constipation and fecal incontinence as well as more advanced treatments (ie, biofeedback, abdominal massage, transanal irrigation, posterior tibial nerve stimulation), caregiver-provided treatments and extended care facilities. Bowel dysfunction problems and related cofactors impact quality of life throughout the MS disease course, requiring appropriate interventions to improve and/or maintain the quality of life of the individual with MS.

Role of the gut microbiome in multiple sclerosis: From etiology to therapeutics

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS that affects around one million people in the United States. Predisposition or protection from this disease is linked with both genetic and environmental factors. In recent years, gut microbiome has emerged as an important environmental factor in the pathobiology of MS. The gut microbiome supports various physiologic functions, including the development and maintenance of the host immune system, the perturbation of which is known as dysbiosis and has been linked with multiple diseases including MS. We and others have shown that people with MS (PwMS) have gut dysbiosis that is characterized by specific gut bacteria being enriched or depleted. Consequently, there is an emphasis on determining the mechanism(s) through which gut bacteria and/or their metabolites alter the course of MS through their ability to provide protection, predispose individuals, or promote disease progression. Improving our understanding of these mechanisms will allow us to harness the enormous potential of the gut microbiome as a diagnostic and/or therapeutic agent. In this chapter, we will discuss current advances in microbiome research in the context of MS, including a review of specific bacteria that are currently linked with this disease, potential mechanisms of disease pathogenesis, and the utility of microbiome-based therapy for PwMS.

Characterization of Neurochemical Signature Alterations in the Enteric Nervous System in Autoimmune Encephalomyelitis

To date, it has remained unclear whether gastrointestinal symptoms, which are frequently observed in patients with multiple sclerosis (MS), are accompanied by pathology of the enteric nervous system (ENS). Here, the neurotransmitter signature of ENS neurons and morphological alterations of interstitial cells of Cajal (ICCs) were studied in patients with MS and mice with experimental autoimmune encephalomyelitis (EAE), which is an animal model of MS. Immunohistochemical analysis was performed on colonic whole mounts from mice with EAE and on paraffin-embedded sections of intestinal tissue from patients with MS. Antibodies against neurotransmitters or their enzymes (including vasoactive intestinal peptide (VIP), neuronal nitric oxide synthase (nNOS), and choline acetyltransferase (ChAT)) were used in conjunction with pan-neuronal markers. In addition, the presence of anoctamin 1 (ANO1)-expressing ICCs was studied. ENS changes were observed in the myenteric plexus, but they were absent in the submucosal plexus of both EAE mice and patients with MS. There was a significant decrease in the percentage of ChAT-positive neurons in EAE mice as opposed to a trend toward an increase in patients with MS. Moreover, while ANO1 expression was decreased in EAE mice, patients with MS displayed a significant increase. Although additional studies are necessary to accomplish an in-depth characterization of ENS alterations in MS, our results imply that such alterations exist and may reveal novel insights into the pathophysiology of MS.

Prevalence and predictors of bowel dysfunction in a large multiple sclerosis outpatient population: an Italian multicenter study

INTRODUCTION

Bowel dysfunction (BD) is reported as a common and disabling symptom in multiple sclerosis (MS) patients. To date, no studies have explored the prevalence of these symptoms in a large multicenter outpatient setting. The aims of the present study are to assess: (i) the prevalence of BD in a large multicenter Italian MS population, and (ii) the correlation between clinico-demographic variables and the severity of BD.

METHODS

Each of the nine participating center screened MS patients prospectively: 1100 subjects were enrolled. All patients underwent the Expanded Disability Status Scale (EDSS) and completed the Neurogenic Bowel Dysfunction score (NBDs). Multivariable linear and logistic regression models were used to assess the association between NBDs and several clinico-demographic variables.

RESULTS

Fourteen percent of MS patients showed a moderate/severe BD (NBDs > 10); this percentage increased in patients with high disability, ranging from 26 to 32%. Moderate/severe BD was more frequent in MS patients with: progressive phenotypes, higher disability, older age, and longer disease duration. NBDs severity was predicted by female sex, ambulation impairment and bladder symptoms.

CONCLUSION

This study confirms the relatively high prevalence of moderate/severe BD in a large, multicenter, unselected, outpatient MS population. BD appears to be mainly associated to female sex and MS-related disability.

Gastrointestinal motility disorders in neurologic disease

The extrinsic and autonomic nervous system intricately controls the major functions of the gastrointestinal tract through the enteric nervous system; these include motor, secretory, sensory, storage, and excretory functions. Disorders of the nervous system affecting gastrointestinal tract function manifest primarily as abnormalities in motor (rather than secretory) functions. Common gastrointestinal symptoms in neurologic disorders include sialorrhea, dysphagia, gastroparesis, intestinal pseudo-obstruction, constipation, diarrhea, and fecal incontinence. Diseases of the entire neural axis ranging from the cerebral hemispheres to the peripheral autonomic nerves can result in gastrointestinal motility disorders. The most common neurologic diseases affecting gastrointestinal function are stroke, parkinsonism, multiple sclerosis, and diabetic neuropathy. Diagnosis involves identification of the neurologic disease and its distribution, and documentation of segmental gut dysfunction, typically using noninvasive imaging, transit measurements, or intraluminal measurements of pressure activity and coordination of motility. Apart from treatment of the underlying neurologic disease, management focuses on restoration of normal hydration and nutrition and pharmacologic treatment of the gut neuromuscular disorder.

Interactions between host genetics and gut microbiota determine susceptibility to CNS autoimmunity

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system. The etiology of MS is multifactorial, with disease risk determined by genetics and environmental factors. An emerging risk factor for immune-mediated diseases is an imbalance in the gut microbiome. However, the identity of gut microbes associated with disease risk, their mechanisms of action, and the interactions with host genetics remain obscure. To address these questions, we utilized the principal autoimmune model of MS, experimental autoimmune encephalomyelitis (EAE), together with a genetically diverse mouse model representing 29 unique host genotypes, interrogated by microbiome sequencing and targeted microbiome manipulation. We identified specific gut bacteria and their metabolic functions associated with EAE susceptibility, implicating short-chain fatty acid metabolism as a key element conserved across multiple host genotypes. In parallel, we used a reductionist approach focused on two of the most disparate phenotypes identified in our screen. Manipulation of the gut microbiome by transplantation and cohousing demonstrated that transfer of these microbiomes into genetically identical hosts was sufficient to modulate EAE susceptibility and systemic metabolite profiles. Parallel bioinformatic approaches identified Lactobacillus reuteri as a commensal species unexpectedly associated with exacerbation of EAE in a genetically susceptible host, which was functionally confirmed by bacterial isolation and commensal colonization studies. These results reveal complex interactions between host genetics and gut microbiota modulating susceptibility to CNS autoimmunity, providing insights into microbiome-directed strategies aimed at lowering the risk for autoimmune disease and underscoring the need to consider host genetics and baseline gut microbiome composition.

The association between the adrenergic hyperactivity and blood pressure values in people with multiple sclerosis

OBJECTIVES

To evaluate the evolution of adrenergic baroreflex sensitivity (BRSa) over 2-year follow-up and to investigate the effect of baseline BRSa indices on blood pressure values after 2 years in people with multiple sclerosis (pwMS).

METHODS

The following data were analysed at baseline and after 2 years: BRSa measured with BRSa1, α-BRSa and β-BRSa, supine and tilted levels of epinephrine and norepinephrine, supine and tilted systolic and diastolic blood pressure levels.

RESULTS

Compared to baseline values, there was no change in α-BRSa (6.96 ± 2.56 vs. 6.64 ± 2.24, p = 0.379) at month 24. α-BRSa at month 24 positively correlated with tilted levels of norepinephrine at month 24 (r_p = 0.357, p = 0.005). Univariable linear regression analysis revealed that α-BRSa at baseline predicts the value of tilted systolic and diastolic blood pressure at month 24 (B = 2.724, 95% CI 1.357-4.091, p < 0.001 and B = 1.489, 95% CI 0.459-2.519, p = 0.005).

CONCLUSION

This study provides further evidence for possible role of α-BRSa as a marker of adrenergic hyperactivity in pwMS. These results may explain increased risk for cardiovascular diseases in pwMS.

[Anorectal disorders in patients with multiple sclerosis: Physiopathology, prevalence, impact, and management]

OBJECTIVE

Neurogenic bowel disorders (NBD) are frequently observed in patients with multiple sclerosis (MS); the prevalence of constipation is estimated to be 35-54 % and fecal incontinence between 29 and 51 % (LE 4). They contribute to the deterioration of patients' quality of life (LE 4). The aim of this article is to review the literature on the physiopathology, prevalence, impact, and management of bowel disorders in patients with MS in order to educate caregivers about their existence and thus help them to optimize therapeutic choices.

MATERIALS AND METHODS

A bibliographic search was conducted between 2000 and 2019 and 31 relevant scientific articles were selected. Relevant references were subsequently added, bringing the total to 50 articles. A level of scientific evidence (LE) was assigned to each article, except for literature reviews.

RESULTS

The origin of NBD is multifactorial and includes impairment of neurological pathways, polypharmacy, behavioural disorders, and loss of autonomy (LE 4). Patients with MS should be questioned about their bowel habits and, in cases of proven NBD, specific management options should be offered. The first step concerns the dietary and lifestyle rules associated with the use of laxatives, suppositories, and/or enemas (LE 4). In the event of failure, therapies such as abdominal massages (LE 1 and 2), biofeedback and transanal irrigation can be proposed (LE 4). Anterograde colonic irrigation may also be an option (LE 4). The efficacy of stimulating the posterior tibial nerve needs to be proven (LE 4). The implantation of a sacral neuromodulation device is, for the moment, difficult due to the impossibility of performing a spinal magnetic resonance imaging during follow-up. A stoma improves the quality of life of patients and should not be proposed too late.

CONCLUSION

Effective treatment of NBD improves the quality of life of patients and reduces the incidence of bladder disorders (LE 4).