Why monkeys do not get multiple sclerosis (spontaneously): An evolutionary approach

A prospective investigation of the effects of soccer heading on cognitive and sensorimotor performances in semi-professional female players

Introduction

Repetitive head impacts (RHI) from routine soccer (football) heading have been suggested to contribute to the long-term development of neurodegenerative disorders. However, scientific evidence concerning the actual risk of these RHI on brain health remains inconclusive. Moreover, female athletes-despite a presumably increased vulnerability toward the effects of RHI-are largely underrepresented in previous approaches. Therefore, our aim was to prospectively investigate the effects of heading on cognitive and sensorimotor performances, health perception, and concussion symptoms in semi-professional female soccer players.

Methods

An extensive test battery was used to assess cognitive and sensorimotor performances as well as health status (SF-36) and concussion symptoms (SCAT3) of a total of 27 female soccer players (22.2 ± 4.2 years) and 15 control subjects (23.2 ± 3.0 years) before and after one-and-a-half years. Throughout this period, soccer players' heading exposure was determined using video analysis.

Results

Subgroup comparisons (control [n = 12], low exposure [n = 7], high exposure [n = 8]) showed no time-dependent differences in SF-36 or SCAT3 scores. Similarly, across most behavioral tests, soccer players' performances evolved equally or more favorably as compared to the control subjects. However, there were significant effects pointing toward slightly negative consequences of heading on aspects of fine motor control (p = 0.001), which were confirmed by correlation and multiple regression analyses. The latter, further, yielded indications for a relationship between heading exposure and negative alterations in postural control (p = 0.002).

Discussion

Our findings do not provide evidence for negative effects of soccer heading on female players' health perception, concussion symptoms, and cognitive performances over the course of one-and-a-half years. However, we found subtle negative alterations in fine motor and postural control that could be attributed to heading exposure. Other factors, like the number of previous head injuries, were not linked to the observed changes. Given the reduction of our initial sample size due to player fluctuation, the results need to be interpreted with caution and validated in larger-scale studies. These should not only focus on cognitive outcomes but also consider sensorimotor changes as a result of RHI from soccer heading.

How myeloid cells shape experimental autoimmune encephalomyelitis: At the crossroads of outside-in immunity

Experimental autoimmune encephalomyelitis (EAE) is an animal model of central nervous system (CNS) autoimmunity. It is most commonly used to mimic aspects of multiple sclerosis (MS), a demyelinating disorder of the human brain and spinal cord. The innate immune response displays one of the core pathophysiological features linked to both the acute and chronic stages of MS. Hence, understanding and targeting the innate immune response is essential. Microglia and other CNS resident MUs, as well as infiltrating myeloid cells, diverge substantially in terms of both their biology and their roles in EAE. Recent advances in the field show that antigen presentation, as well as disease-propagating and regulatory interactions with lymphocytes, can be attributed to specific myeloid cell types and cell states in EAE lesions, following a distinct temporal pattern during disease initiation, propagation and recovery. Furthermore, single-cell techniques enable the assessment of characteristic proinflammatory as well as beneficial cell states, and identification of potential treatment targets. Here, we discuss the principles of EAE induction and protocols for varying experimental paradigms, the composition of the myeloid compartment of the CNS during health and disease, and systematically review effects on myeloid cells for therapeutic approaches in EAE.

Changes in thumb tapping rates and central motor conduction times are associated in persons with multiple sclerosis

Introduction

In persons with multiple sclerosis, nerve conductivity can be reduced. The assessment is generally performed via motor evoked potentials (MEP). So far, a strongly associated motor performance surrogate for changes in the extracted central motor conduction time (CMCT) is missing.

Methods

CMCT and performance in the nine-hole peg test and maximum thumb tapping frequencies over 10 s of 12 persons with multiple sclerosis were measured prior to and after training over 5 consecutive days. Each training consisted of 10,000 thumb taps at maximum effort with the dominant upper limb.

Results

The dominant upper limb improved in maximum tapping frequency over 10 s (d = 0.79) and 10,000 taps (d = 1.04), the nine-hole peg test (d = 0.60), and CMCT (d = 0.52). The nondominant upper limb only improved in the nine-hole peg test (d = 0.38). Models of multiple linear regression predicted 0.78 (model 1, tapping performance as factors) and 0.87 (model 2, patient baseline characteristics as factors) of the variance in CMCT changes.

Discussion

Changes in CMCT were well predictable, although the assessment of those surrogates is either not economic (model 1) or rather describing a potential of change (model 2). However, we were able to show moderate changes in CMCT within 5 days.

Secondary Prevention in Radiologically Isolated Syndromes and Prodromal Stages of Multiple Sclerosis

Following the extraordinary progress in the treatment of multiple sclerosis (MS), two major unmet needs remain: understanding the etiology of the disease and, hence, designing definitive cures (this perspective is neither at hand, nor it can be taken for granted that the etiologic targets will be readily treatable); the prevention of an overt and disabling disease, which seems to be a more realistic and pragmatic perspective, as the integration of genetic data with endophenotypes, MRI, and other biomarkers ameliorates our ability to identify early neuroinflammation. Radiologically isolated syndrome (RIS; diagnosed when the unanticipated MRI finding of brain spatial dissemination of focal white matter lesions highly suggestive of MS occurs in subjects without symptoms of MS, and with normal neurological examinations) and the recently focused “prodromal MS” are conditions at risk of conversion toward overt disease. Here, we explore the possibility of secondary prevention approaches in these early stages of neuroinflammation. RIS and prodromal MS are rare conditions, which suggest the importance of Study Groups and Disease Registry to implement informative clinical trials. We summarize ongoing preventive approaches in the early stages of the demyelinating process, especially in RIS conditions. Moreover, we highlight the importance of the biomarkers and the predictors of evolution to overt disease, which may be useful to select the individuals at risk of conversion to clinically isolated syndrome (CIS) and/or clinically definite MS. Finally, we illustrate the importance of the endophenotypes to test the frontline immunomodulatory approach for preventive strategies. Future investigations, especially in relatives of patients, based on MRI techniques and biological studies (better with integrated approaches) may provide opportunities to understand the MS early causal cascade and may help to identify a “therapeutic window” to potentially reverse early disease processes.

Multiple sclerosis and the microbiota

Multiple sclerosis (MS), a neurological autoimmune disorder, has recently been linked to neuro-inflammatory influences from the gut. In this review, we address the idea that evolutionary mismatches could affect the pathogenesis of MS via the gut microbiota. The evolution of symbiosis as well as the recent introduction of evolutionary mismatches is considered, and evidence regarding the impact of diet on the MS-associated microbiota is evaluated. Distinctive microbial community compositions associated with the gut microbiota of MS patients are difficult to identify, and substantial study-to-study variation and even larger variations between individual profiles of MS patients are observed. Furthermore, although some dietary changes impact the progression of MS, MS-associated features of microbiota were found to be not necessarily associated with diet per se. In addition, immune function in MS patients potentially drives changes in microbial composition directly, in at least some individuals. Finally, assessment of evolutionary histories of animals with their gut symbionts suggests that the impact of evolutionary mismatch on the microbiota is less concerning than mismatches affecting helminths and protists. These observations suggest that the benefits of an anti-inflammatory diet for patients with MS may not be mediated by the microbiota per se. Furthermore, any alteration of the microbiota found in association with MS may be an effect rather than a cause. This conclusion is consistent with other studies indicating that a loss of complex eukaryotic symbionts, including helminths and protists, is a pivotal evolutionary mismatch that potentiates the increased prevalence of autoimmunity within a population.

Unraveling Human Brain Development and Evolution Using Organoid Models

Brain organoids are proving to be physiologically relevant models for studying human brain development in terms of temporal transcriptional signature recapitulation, dynamic cytoarchitectural development, and functional electrophysiological maturation. Several studies have employed brain organoid technologies to elucidate human-specific processes of brain development, gene expression, and cellular maturation by comparing human-derived brain organoids to those of non-human primates (NHPs). Brain organoids have been established from a variety of NHP pluripotent stem cell (PSC) lines and many protocols are now available for generating brain organoids capable of reproducibly representing specific brain region identities. Innumerous combinations of brain region specific organoids derived from different human and NHP PSCs, with CRISPR-Cas9 gene editing techniques and strategies to promote advanced stages of maturation, will successfully establish complex brain model systems for the accurate representation and elucidation of human brain development. Identified human-specific processes of brain development are likely vulnerable to dysregulation and could result in the identification of therapeutic targets or disease prevention strategies. Here, we discuss the potential of brain organoids to successfully model human-specific processes of brain development and explore current strategies for pinpointing these differences.

State and trait of finger tapping performance in multiple sclerosis

Finger tapping tests have been shown feasible to assess motor performance in multiple sclerosis (MS) and were observed to be strongly associated with the estimated clinical severity of the disease. Therefore, tapping tests could be an adequate tool to assess disease status in MS. In this study we examined potential influencing factors on a maximum tapping task with the whole upper-limb for 10 s in 40 MS patients using linear mixed effects modelling. Patients were tested in three sessions with two trials per body-side per session over the course of 4–27 days of inpatient rehabilitation. Tested factors were the expanded disability scale (EDSS) score, laterality of MS, age, sex, hand dominance, time of day, session, trial (first or second), time between sessions, and the reported day form. A second model used these factors to examine the self-reported day form of patients. Linear mixed effects modelling indicated the tapping test to have a good inter-trial (proportional variance < 0.01) and inter-session reliability (non-significant; when controlling for time between sessions), an influence of hand-dominance (proportional variance 0.08), to be strongly associated with the EDSS (eta² = 0.22, interaction with laterality of MS eta² = 0.12) and to be not associated with the reported day form. The model explained 87% (p < 0.01) of variance in tapping performance. Lastly, we were able to observe a positive effect of neurologic inpatient rehabilitation on task performance obvious from a significant effect of the time between sessions (eta² = 0.007; longer time spans between sessions were associated with higher increments in performance). Day form was only impacted by EDSS and the time of the day (p < 0.01, R² = 0.57, eta²_TIME = 0.017, eta²_EDSS = 01.19). We conclude that the tapping test is a reliable and valid assessment tool for MS.

Inpatient Rehabilitation: Prediction of Changes in Sensorimotor Performance in Multiple Sclerosis: A Pilot Study

Inpatient rehabilitation has been shown to be an effective intervention for sensorimotor performance in multiple sclerosis (MS) patients. So far, predictions of the rehabilitation outcomes are limited. The objective was to predict inpatient rehabilitation outcomes by changes in the Watzmann Severity Scale (WSS), a statistical estimation of the EDSS by sensorimotor capacity. Sensorimotor performance and physical activity during rehabilitation (by actigraphy) were assessed in a sample of 28 MS patients at a facility for neurorehabilitation. Daily changes in the WSS were predicted by a model of multiple linear regression. The resulting model had an R²_adjusted of 0.48 (p < 0.01) and revealed five impacting factors (a reduction in the WSS represents an improvement): the number of steps (β-weight = 0.52, p < 0.01), the duration of nocturnal rest time (β-weight = 0.46, p = 0.01), the EDSS at entry (β-weight = 0.38, p = 0.03), a relapsing-remitting MS (β-weight = 0.37, p = 0.03), and the performance in a visuomotor pursuit task with time pressure (β-weight = −0.35, p = 0.04). One standard deviation improvement was predicted when the patient at admission yielded 6600 fewer steps per day, 94 min less rest per night, −2.7 points in the EDSS at entry, a relapsing-remitting MS, and a pursuit task performance that decreased by 2.2 standard deviations. Overall, the patients improved by −0.22 ± 0.51 WSS points during 19.3 ± 4.5 d of inpatient rehabilitation. Different potential explanations of the findings are discussed, one of which proposes that the results reflect an unhealthy lifestyle which, in addition to MS, would explain the higher predicted improvements by rehabilitation tackling both MS and the patients’ lifestyle.

Sensorimotor function does not predict quality of life in persons with multiple sclerosis

Quality of life (QOL) has been reported to be reduced in persons with multiple sclerosis. Further, associations between QOL and the clinical severity of the disease as well as sensorimotor function were shown. We reinvestigated impacting factors on QOL by the additional assessment of depression, fatigue, satisfaction with life, and a battery of end-effector based assessments of sensorimotor functioning. Models of multiple linear regression revealed everyday life activity limitations to be the driving factor within the used questionnaire and no association with sensorimotor tests, but depression, fatigue, and satisfaction with life. We conclude that either psycho-emotional coping and adaptability are the dominant determinant of QOL or that QOL is in need of a quantitative and objective reconceptualization.

Out of balance: the role of evolutionary mismatches in the sex disparity in autoimmune disease

Over the past century autoimmune disease incidence has increased rapidly in (post-) industrialised, affluent societies, suggesting that changes in ecology and lifestyle are driving this development. Epidemiological studies show that (i) 80% of autoimmune disease patients are female, (ii) autoimmune diseases co-occur more often in women, and (iii) the incidence of some autoimmune diseases is increasing faster in women than in men. The female preponderance in autoimmunity is most pronounced between puberty and menopause, suggesting that diverging sex hormone levels during the reproductive years are implicated in autoimmune disease development. Using an evolutionary perspective, we build on the hypotheses that female immunity is cyclical in menstruating species and that natural selection shaped the female immune system to optimise the implantation and gestation of a semi-allogeneic foetus. We propose that cyclical immunomodulation and female immune tolerance mechanisms are currently out of balance because of a mismatch between the conditions under which they evolved and (post-)industrialised, affluent lifestyles. We suggest that current changes in autoimmune disease prevalence may be caused by increases in lifetime exposure to cyclical immunomodulation and ovarian hormone exposure, reduced immune challenges, increased reproductive lifespan, changed reproductive patterns, and enhanced positive energy balance associated with (post-)industrialised, affluent lifestyles. We discuss proximate mechanisms by which oestrogen and progesterone influence tolerance induction and immunomodulation, and review the effect of the menstrual cycle, pregnancy, and contraceptive use on autoimmune disease incidence and symptoms.

Statistical field theory of the transmission of nerve impulses

Background

Stochastic processes leading voltage-gated ion channel dynamics on the nerve cell membrane are a sufficient condition to describe membrane conductance through statistical mechanics of disordered and complex systems.

Results

Voltage-gated ion channels in the nerve cell membrane are described by the Ising model. Stochastic circuit elements called “Ising Neural Machines” are introduced. Action potentials are described as quasi-particles of a statistical field theory for the Ising system.

Conclusions

The particle description of action potentials is a new point of view and a powerful tool to describe the generation and propagation of nerve impulses, especially when classical electrophysiological models break down.

The particle description of action potentials allows us to develop a new generation of devices to study neurodegenerative and demyelinating diseases as Multiple Sclerosis and Alzheimer’s disease, even integrated by connectomes. It is also suitable for the study of complex networks, quantum computing, artificial intelligence, machine and deep learning, cryptography, ultra-fast lines for entanglement experiments and many other applications of medical, physical and engineering interest.

Thyroid Hormone and Neural Stem Cells: Repair Potential Following Brain and Spinal Cord Injury

Neurodegenerative diseases are characterized by chronic neuronal and/or glial cell loss, while traumatic injury is often accompanied by the acute loss of both. Multipotent neural stem cells (NSCs) in the adult mammalian brain spontaneously proliferate, forming neuronal and glial progenitors that migrate toward lesion sites upon injury. However, they fail to replace neurons and glial cells due to molecular inhibition and the lack of pro-regenerative cues. A major challenge in regenerative biology therefore is to unveil signaling pathways that could override molecular brakes and boost endogenous repair. In physiological conditions, thyroid hormone (TH) acts on NSC commitment in the subventricular zone, and the subgranular zone, the two largest NSC niches in mammals, including humans. Here, we discuss whether TH could have beneficial actions in various pathological contexts too, by evaluating recent data obtained in mammalian models of multiple sclerosis (MS; loss of oligodendroglial cells), Alzheimer’s disease (loss of neuronal cells), stroke and spinal cord injury (neuroglial cell loss). So far, TH has shown promising effects as a stimulator of remyelination in MS models, while its role in NSC-mediated repair in other diseases remains elusive. Disentangling the spatiotemporal aspects of the injury-driven repair response as well as the molecular and cellular mechanisms by which TH acts, could unveil new ways to further exploit its pro-regenerative potential, while TH (ant)agonists with cell type-specific action could provide safer and more target-directed approaches that translate easier to clinical settings.

Decreased second to fourth digit ratios in female multiple sclerosis patients

BACKGROUND

Sex-related differences in multiple sclerosis (MS) suggest a possible role of prenatal sex hormones in the pathogenesis. The aim of this study was to investigate whether the 2D:4D ratio, considered a predictor of prenatal hormonal exposure, in MS patients differ from that in healthy controls.

METHODS

Two hundred MS patients and one hundred seventy healthy control subjects with similar age and sex distribution enrolled. All participants were right-handed. The right hands of all participants were scanned using a digital scanner. Measurements of second and fourth digit lengths were made from digital scans. The 2D:4D ratio was calculated by dividing the length of the second digit by the length of the fourth digit.

RESULTS

A total of 171 MS patients' and 159 healthy controls' digit scans included in the study. The MS group consisted of 94 females (mean age 38.32 ± 10.5) and 77 males (mean age 42.06 ± 11.8) and the control group of 86 females (mean age 40.24 ± 9.7) and 73 males (mean age 38.49 ± 11.6). 2D:4D ratios of female MS patients were significantly lower than those of healthy females (p=0.004). Although 2D:4D ratios of male patients with MS were lower than those of healthy males, this difference was not statistically significant (p=0.33). There was no significant correlation between the 2D:4D ratio, EDSS levels or duration of the disease in male or female MS patients (p<0.05).

CONCLUSION

Although our results suggest that a prenatal hormonal balance in favor of androgenic activity may be a risk factor for MS, complex factors mediating the actions of sex hormones on target cells should always be considered when evaluating the effects of sex hormones.

Reverse engineering human brain evolution using organoid models

Primate brains vary dramatically in size and organization, but the genetic and developmental basis for these differences has been difficult to study due to lack of experimental models. Pluripotent stem cells and brain organoids provide a potential opportunity for comparative and functional studies of evolutionary differences, particularly during the early stages of neurogenesis. However, many challenges remain, including isolating stem cell lines from additional great ape individuals and species to capture the breadth of ape genetic diversity, improving the reproducibility of organoid models to study evolved differences in cell composition and combining multiple brain regions to capture connectivity relationships. Here, we describe strategies for identifying evolved developmental differences between humans and non-human primates and for isolating the underlying cellular and genetic mechanisms using comparative analyses, chimeric organoid culture, and genome engineering. In particular, we focus on how organoid models could ultimately be applied beyond studies of progenitor cell evolution to decode the origin of recent changes in cellular organization, connectivity patterns, myelination, synaptic development, and physiology that have been implicated in human cognition.