Impact of endocrine dysregulation on disability and non-motor symptoms in pediatric onset multiple sclerosis

Background

Pediatric onset multiple sclerosis (POMS) commonly occurs at the time of various endocrine changes. Evaluation of the impact of endocrine status on disease severity in POMS has not been previously explored.

Objective

This study sought to evaluate if sex and stress hormones in children with POMS impact motor and non-motor diseases severity.

Methods

A single-center case control study was performed. Individuals with POMS were compared to individuals without neurologic disease. Each individual had three blood draws assessing stress and sex hormones between 07:00 and 09:00. Measures of fatigue (Epworth sleepiness scale), depression (PHQ-9), and quality of life (PedsQL) assessed at each visit.

Results

Forty individuals with POMS and 40 controls were enrolled. Individuals with POMS had lower free testosterone (p = 0.003), cortisol (p < 0.001), and ACTH (p < 0.001) and had higher progesterone (p = 0.025) levels than controls. Relapses and EDSS were not impacted by endocrine variables. The POMS cohort had a significantly higher Epworth score (p < 0.001), PHQ-9 score (p < 0.001), and lower PQL score (p < 0.001) than controls. Non-motor measures were not associated with endocrine status.

Conclusion

Free testosterone, cortisol, ACTH, and progesterone were abnormal in children with POMS although there was no association between endocrine status and markers of disease severity or non-motor symptoms of MS.

iPSCs from people with MS can differentiate into oligodendrocytes in a homeostatic but not an inflammatory milieu

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS) that results in variable severities of neurodegeneration. The understanding of MS has been limited by the inaccessibility of the affected cells and the lengthy timeframe of disease development. However, recent advances in stem cell technology have facilitated the bypassing of some of these challenges. Towards gaining a greater understanding of the innate potential of stem cells from people with varying degrees of disability, we generated induced pluripotent stem cells (iPSCs) from peripheral blood mononuclear cells derived from stable and progressive MS patients, and then further differentiated them into oligodendrocyte (OL) lineage cells. We analyzed differentiation under both homeostatic and inflammatory conditions via sustained exposure to low-dose interferon gamma (IFNγ), a prominent cytokine in MS. We found that all iPSC lines differentiated into mature myelinating OLs, but chronic exposure to IFNγ dramatically inhibited differentiation in both MS groups, particularly if exposure was initiated during the pre-progenitor stage. Low-dose IFNγ was not toxic but led to an early upregulation of interferon response genes in OPCs followed by an apparent redirection in lineage commitment from OL to a neuron-like phenotype in a significant portion of the treated cells. Our results reveal that a chronic low-grade inflammatory environment may have profound effects on the efficacy of regenerative therapies.

The sensitivity of network statistics to incomplete electrode sampling on intracranial EEG

Network neuroscience applied to epilepsy holds promise to map pathological networks, localize seizure generators, and inform targeted interventions to control seizures. However, incomplete sampling of the epileptic brain because of sparse placement of intracranial electrodes may affect model results. In this study, we evaluate the sensitivity of several published network measures to incomplete spatial sampling and propose an algorithm using network subsampling to determine confidence in model results. We retrospectively evaluated intracranial EEG data from 28 patients implanted with grid, strip, and depth electrodes during evaluation for epilepsy surgery. We recalculated global and local network metrics after randomly and systematically removing subsets of intracranial EEG electrode contacts. We found that sensitivity to incomplete sampling varied significantly across network metrics. This sensitivity was largely independent of whether seizure onset zone contacts were targeted or spared from removal. We present an algorithm using random subsampling to compute patient-specific confidence intervals for network localizations. Our findings highlight the difference in robustness between commonly used network metrics and provide tools to assess confidence in intracranial network localization. We present these techniques as an important step toward translating personalized network models of seizures into rigorous, quantitative approaches to invasive therapy.

Variants in myelin regulatory factor (MYRF) cause autosomal dominant and syndromic nanophthalmos in humans and retinal degeneration in mice

Nanophthalmos is a rare, potentially devastating eye condition characterized by small eyes with relatively normal anatomy, a high hyperopic refractive error, and frequent association with angle closure glaucoma and vision loss. The condition constitutes the extreme of hyperopia or farsightedness, a common refractive error that is associated with strabismus and amblyopia in children. NNO1 was the first mapped nanophthalmos locus. We used combined pooled exome sequencing and strong linkage data in the large family used to map this locus to identify a canonical splice site alteration upstream of the last exon of the gene encoding myelin regulatory factor (MYRF c.3376-1G>A), a membrane bound transcription factor that undergoes autoproteolytic cleavage for nuclear localization. This variant produced a stable RNA transcript, leading to a frameshift mutation p.Gly1126Valfs*31 in the C-terminus of the protein. In addition, we identified an early truncating MYRF frameshift mutation, c.769dupC (p.S264QfsX74), in a patient with extreme axial hyperopia and syndromic features. Myrf conditional knockout mice (CKO) developed depigmentation of the retinal pigment epithelium (RPE) and retinal degeneration supporting a role of this gene in retinal and RPE development. Furthermore, we demonstrated the reduced expression of Tmem98, another known nanophthalmos gene, in Myrf CKO mice, and the physical interaction of MYRF with TMEM98. Our study establishes MYRF as a nanophthalmos gene and uncovers a new pathway for eye growth and development.