A spring to summer shift of pro-inflammatory cytokine production in multiple sclerosis patients

Detecting seasonal trends in optic neuritis within the Ottawa region

OBJECTIVE

In this study we aim to determine seasonal patterns underlying optic neuritis (ON) onset that may provide valuable epidemiologic information and help delineate causative or protective factors.

DESIGN

Single-centre retrospective chart review.

METHODS

A database search of centralized electronic health records was completed using diagnostic codes employed at the Ottawa Eye Institute for data collection. Charts were reviewed for documentation supporting a diagnosis of ON falling into the following categories: multiple sclerosis ON and clinically isolated syndrome ON, myelin oligodendrocyte glycoprotein ON, neuromyelitis optica ON, and idiopathic ON. Date of onset, biological sex, and age were extracted from each chart. Data were analyzed for calculation of frequency by season and overall pooled seasonal trends of all cases of ON.

RESULTS

From the 218 included patients with ON, there was no statistically significant seasonal correlation. The overall trend of ON was lowest in winter and spring (22% and 23%, respectively) and highest in summer and fall (28% and 27% respective). Divided further, multiple sclerosis ON or clinically isolated syndrome ON rates (n = 144) were lowest in the spring (21%) and highest in fall (29%); myelin oligodendrocyte glycoprotein ON rates (n = 25) were lowest in winter (16%) and highest in summer and fall (both at 32%); neuromyelitis optica ON rates (n = 16) were lowest in fall (12.5%) and highest in winter and summer (both at 31.25%); and idiopathic ON rates (n = 33) were lowest in fall (18%) and highest in spring (33%).

CONCLUSIONS

The overall ON seasonal trend appears to have a predilection for the summer and fall months, which may be explained by warmer weather and viral infections as risk factors for multiple sclerosis relapse during those seasons.

Multiple sclerosis and circadian rhythms: Can diet act as a treatment?

Multiple sclerosis (MS) is an autoimmune inflammatory and neurodegenerative disease of the central nervous system (CNS) with increasing incidence and prevalence. MS is associated with inflammatory and metabolic disturbances that, as preliminary human and animal data suggest, might be mediated by disruption of circadian rhythmicity. Nutrition habits can influence the risk for MS, and dietary interventions may be effective in modulating MS disease course. Chronotherapeutic approaches such as time-restricted eating (TRE) may benefit people with MS by stabilizing the circadian clock and restoring immunological and metabolic rhythms, thus potentially counteracting disease progression. This review provides a summary of selected studies on dietary intervention in MS, circadian rhythms, and their disruption in MS, including clock gene variations, circadian hormones, and retino-hypothalamic tract changes. Furthermore, we present studies that reported diurnal variations in MS, which might result from circadian disruption. And lastly, we suggest how chrononutritive approaches like TRE might counteract MS disease activity.

Sensory Integration Disorders in Patients with Multiple Sclerosis

Sensory integration disorder (SID) is also called, interchangeably, sensory processing disorder (SPD). Multiple sclerosis (MS) is an autoimmune, chronic, neurological disease of the central nervous system. Sensorimotor function disorders are present in both multiple sclerosis and SID. The study aimed to assess the SID among patients with MS and included 141 patients with relapse-remitting MS and 72 participants in the control group. To assess SID in both groups, a questionnaire prepared by Daniel Travis was used. Additionally, participants answered questions regarding their age, gender, handedness and in the study group about the duration of the disease, relapses in the past year and the advancement of the disease using EDSS. The occurrence of sensory seeking was significantly more frequent in the MS patients with relapses in the past year. Patients with MS had more often general disorders of sensory integration in the past. However, healthy subjects significantly more often showed the severity of social and emotional disorders in the past. Currently, the group of MS patients has a greater intensity of sensor-based motor abilities. The study revealed more severe SID in MS patients than in the control group. Still, more research is needed in this field.

An evaluation of the recognised systemic inflammatory biomarkers of chronic sub-optimal inflammation provides evidence for inflammageing (IFA) during multiple sclerosis (MS)

The pathogenesis of the human demyelinating disorder multiple sclerosis (MS) involves the loss of immune tolerance to self-neuroantigens. A deterioration in immune tolerance is linked to inherent immune ageing, or immunosenescence (ISC). Previous work by the author has confirmed the presence of ISC during MS. Moreover, evidence verified a prematurely aged immune system that may change the frequency and profile of MS through an altered decline in immune tolerance. Immune ageing is closely linked to a chronic systemic sub-optimal inflammation, termed inflammageing (IFA), which disrupts the efficiency of immune tolerance by varying the dynamics of ISC that includes accelerated changes to the immune system over time. Therefore, a shifting deterioration in immunological tolerance may evolve during MS through adversely-scheduled effects of IFA on ISC. However, there is, to date, no collective proof of ongoing IFA during MS. The Review addresses the constraint and provides a systematic critique of compelling evidence, through appraisal of IFA-related biomarker studies, to support the occurrence of a sub-optimal inflammation during MS. The findings justify further work to unequivocally demonstrate IFA in MS and provide additional insight into the complex pathology and developing epidemiology of the disease.

Seasonal Variations in Macrophages/Microglia Underlie Changes in the Mouse Model of Multiple Sclerosis Severity

Both immune and neurodegenerative mechanisms underlie multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). MS/EAE are triggered by encephalitogenic immune cells, including Th1 and Th17 cells, whereas T regulatory (Treg) cells are involved in inflammation resolution. Pro-inflammatory macrophages/microglia also play a deleterious role in the disease. Seasonal variations in MS relapses, active lesions, and pro- and anti-inflammatory cytokine levels have been described in MS patients and have been related with both perinatal and adult exposure to sunlight and other environmental factors. However, some data in EAE mice suggest that these variations might be, at least partially, endogenously determined. Thus, our objective was to study the effect of the season of birth and disease induction on the course of EAE, and immune cell infiltration in the central nervous system (CNS) in myelin oligodendrocyte glycoprotein (MOG_35-55)-induced EAE in 8 weeks old, female C57BL/6N mice maintained under constant, controlled conditions. EAE severity as well as pathogenic (Th1, Th17, macrophages/microglia) and protective (Treg) subsets was found to vary according to the season of birth or of EAE induction. Summer-born or summer-immunized animals developed a milder disease, which coincided with variations in numbers of T effector/regulatory subsets, and significantly low numbers of macrophages/microglia. These results suggest that endogenous rhythms in immune responses might cause seasonal variations in EAE severity, and, maybe, in the course of MS, and that they might be related to macrophages/microglia.