Increasing Incidence in Relapsing-Remitting MS and High Rates among Young Women in Finland: A Thirty-Year Follow-Up

Inhibiting microglia exacerbates the early effects of cuprizone in males in a rat model of multiple sclerosis, with no effect in females

Hyper-activity of the brain's innate immune cells, microglia, is a hallmark of multiple sclerosis (MS). However, it is not clear whether this involvement of microglia is beneficial or detrimental or whether manipulating microglial activity may be therapeutic. We investigated if inhibiting microglial activity with minocycline prevents the early changes in oligodendrocyte and myelin-related markers associated with a demyelinating challenge in adult female and male rats. Cuprizone reduced the expression of myelin and oligodendrocyte genes in both females and males, reflective of cuprizone intoxication and the early phases demyelination, and reduced the number of oligodendrocytes in the corpus callosum. However, we see notable differences in the role for microglia in this response between females and males. In males, myelin and oligodendrocyte genes, as well as oligodendrocytes were also reduced by minocycline treatment; an effect that was not seen in females. In males, but not females, early changes in oligodendrocyte and myelin-related genes were associated with microglial proliferation in corpus callosum, and this increase was reversed by minocycline. These data indicate sex-specific effects of inhibiting microglia on the early changes leading to demyelination in an MS model and suggest microglia may play a key role in myelin stability in males but not in females. This highlights a strong need for sex-specific understanding of disease development in MS and suggest that treatments targeting microglia may be more effective in males than in females due to differing mechanisms of disease progression.

How does Nogo receptor influence demyelination and remyelination in the context of multiple sclerosis?

Multiple sclerosis (MS) can progress with neurodegeneration as a consequence of chronic inflammatory mechanisms that drive neural cell loss and/or neuroaxonal dystrophy in the central nervous system. Immune-mediated mechanisms can accumulate myelin debris in the disease extracellular milieu during chronic-active demyelination that can limit neurorepair/plasticity and experimental evidence suggests that potentiated removal of myelin debris can promote neurorepair in models of MS. The myelin-associated inhibitory factors (MAIFs) are integral contributors to neurodegenerative processes in models of trauma and experimental MS-like disease that can be targeted to promote neurorepair. This review highlights the molecular and cellular mechanisms that drive neurodegeneration as a consequence of chronic-active inflammation and outlines plausible therapeutic approaches to antagonize the MAIFs during the evolution of neuroinflammatory lesions. Moreover, investigative lines for translation of targeted therapies against these myelin inhibitors are defined with an emphasis on the chief MAIF, Nogo-A, that may demonstrate clinical efficacy of neurorepair during progressive MS.

An internet-based survey of synesthesia in multiple sclerosis: Incidence, characteristics and implications

Objective Prior work raises the interesting possibility that both multiple sclerosis and synesthesia share a common etiology, that being immune system dysfunction, as well as neuroanatomical and neurochemical abnormalities, including those involving white matter and serotonergic pathways, respectively. Given these links between these two syndromes, we examined the possibility that prevalence of synesthesia would be elevated in a population of individuals with MS, relative to what is thought to be the prevalence in the neurotypical population. It was not known whether synesthesia might be a marker for subsequent development of MS, or if synesthesia might reflect neurological damage resulting from MS disease progression. Method Individuals with self- reported clinically definite MS were recruited online via the internet and social media using sites specifically relevant to the MS community. Data from 147 individuals who completed several questionnaires related to synesthesia were analyzed. Results Depending on criteria, between approximately 7 and 16% of individuals with MS reported synesthesia here. This is an estimated 1.57 to 3.55 times increased incidence of synesthesia here relative to previous findings in neurotypical samples. Limitations of the study include that this was an internet survey, and that synesthesia was not directly assessed in this sample. Conclusions Results suggest a link between the syndromes, primarily indicating that synesthesia may be a marker for subsequent MS development, and the implications and directions for future study are discussed.

Trends and characteristics of infection-related hospital admissions in multiple sclerosis patients in Southwest Finland in 2009-2018

BACKGROUND

Multiple sclerosis (MS) patients are at increased risk for infections. The aim of this study was to investigate the trends in hospital admissions of patients with MS and to identify the factors predisposing to infection-related admissions.

METHODS

Hospital admissions with MS as a primary or an auxiliary diagnosis in the hospital district of Southwest Finland in 2009-2018 were searched and MS patients with infection admissions compared with other MS patients in the hospital district. Data were derived from hospital registries, patient charts and the Finnish MS register. Group comparisons were performed using Pearson´s chi-squared test, Fisher´s exact test or Wilcoxon rank sum test. Overdispersion-adjusted Poisson regression was used to analyze the annual admission numbers and multivariable logistic regression to examine the predictors of infection-related admissions.

RESULTS

1380 hospital admissions for 532 patients were identified. The annual number of admissions decreased by 8.9% annually (p<0.001). Proportion of infection-related admissions declined from 26.5% to 19.5% (p = 0.049). The patients with infection admissions were on average 8.2 years older (p<0.001), more often male (p<0.001), had on average 5.3 years longer disease duration (p<0.001), more disability (median EDSS 5.0 vs. 2.0; p<0.001), more often progressive disease (p<0.001) and more comorbidities (p = 0.006) than other MS patients. Disease modifying therapies (DMTs) were used less often by patients with infection admissions (p<0.001). Infection admissions were not associated with the number of recent relapses. In-hospital mortality was higher in the infection-related admissions (3.57% vs 0.29%; p<0.001). Only 14.3% of patients with over two infection admissions had a DMT during the study period.

CONCLUSION

Hospital admissions, with or without an infection, have become more infrequent in MS patients of Southwest Finland over the decade from 2009 to 2018. Infection-related admissions were associated with lesser use of DMTs, older age, male gender and disability.

Multiple sclerosis prevalence in 2000 and 2010 in Western Finland

OBJECTIVE

To study ten-year change in MS prevalence in the Province of Western Finland in Tampere University Hospital District located in 62.7°N, 23.7°E.

METHODS

Age-standardized prevalence/10⁵ by using direct standardization in European Standard Population (ESP2013) and crude prevalence/10⁵ with 95% confidence interval (95% CI) were assessed among resident MS cases fulfilling Poser criteria by sex and disease course in 31.12.2000 and 31.12.2010. MS-related disability and disease-modifying treatment (DMT) use were estimated in 31.12.2010.

RESULTS

Crude prevalence increased 49% from 129/10⁵ (95% CI 121-137) in 2000 (N 1080) to 196/10⁵ (187-203) in 2010 (N 1666). Age-standardized prevalence increased 45% from 133/10⁵ (127-140) to 192/10⁵ (184-200) and peaked in 40- to 49-year age-group. Age-standardized prevalence increased 58% among women from 176/10⁵ (171-176) to 277/10⁵ (270-284) and 31% among men from 91/10⁵ (87-95) to 119/10⁵ (115-124). Increase in RRMS was 61% from 111/10⁵ (105-117) to 179/10⁵ (171-186), and decrease in PPMS was 14% from 21/10⁵ (19-24) to 18/10⁵ (15-21).  In 2010 among the 52% RRMS cases on DMT, MS-related disability was mild in 50%. In total, cohort disability was mild in 46%, moderate to severe in 47%, and information was not available in 14%.

CONCLUSION

A significant increase in prevalence was observed in Western Finland. Increase was higher among women and in relapsing-remitting onset MS. Disability showed age- and disease course-specific variation.

Multiple sclerosis epidemiology in Finland: Regional differences and high incidence

OBJECTIVES

Studies on the east-west gradient of multiple sclerosis (MS) are scarce. In Finland, epidemiological differences have been only partially elucidated, but the MS risk is high, and it has been claimed that the occurrence follows a longitudinal gradient. In this register-based study, we updated the MS epidemiology in southwest Finland (SwF) and compared it to the easternmost hospital district, North Karelia (NK), for which no previous data exist.

MATERIALS AND METHODS

Patients with ICD-10 code G35 were identified from hospital district administrative data. Patient records were reviewed to include only cases with a definitive diagnosis. Incidence period covered 5 years (2012-2016), and the prevalence date was December 31, 2016. Results were standardized using the direct method.

RESULTS

A total of 1184 persons had MS in SwF and 253 persons in NK at the end of 2016. The prevalence was 280/100 000 (95% CI 264-296) in SwF and 168/100 000 (95% CI 148-190) in NK (age-standardized for the European standard population 2013). During the incidence period, 211 new MS diagnoses were made in SwF and 49 in NK. The annual age-standardized (ESP 2013) incidence was 12.1/100 000 person-years (95% CI 10.5-13.8) in SwF and 8.6/100 000 person-years (95% CI 6.4-11.2) in NK in the age-group 10-69 years.

CONCLUSIONS

There are regional differences in MS epidemiology in Finland, possibly related to demographic, social, and genetic circumstances, but the retrospective nature and limited sample size of this study might introduce some uncertainty to the calculations. SwF is a region with a globally very high risk for MS.

Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant) in Cognitively Impaired Patients

To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI) and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19–90 years) displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54), 57.14% central atrophy (N=88), and 44.52% temporal atrophy (N=69). A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III) scores differentially across various brain loci. Delayed latency (p=0.0740) was marginally associated with temporal atrophy; reduced fractional anisotropy (FA) in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115). Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787). In the centrum semiovale (CS), reduced FA correlated with visual memory (p=0.0622). Lower demyelination correlated with higher P300 amplitude (p=0.0002). Compared to males, females have higher demyelination (p=0.0064). Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165). Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087). In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740); high auditory memory and low temporal atrophy (p=0.0417); and high working memory and low temporal atrophy (p=0.0166). Central atrophy correlated with aging and immediate memory (p=0.0294): the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost-effective methods utilizable in primary care medicine following further confirmation.