Critical Components for Spontaneous Activity and Rhythm Generation in Spinal Cord Circuits in Culture

Neuronal excitability contributes to rhythm generation in central pattern generating networks (CPGs). In spinal cord CPGs, such intrinsic excitability partly relies on persistent sodium currents (INaP), whereas respiratory CPGs additionally depend on calcium-activated cation currents (ICAN). Here, we investigated the contributions of INaP and ICAN to spontaneous rhythm generation in neuronal networks of the spinal cord and whether they mainly involve Hb9 neurons. We used cultures of ventral and transverse slices from the E13-14 embryonic rodent lumbar spinal cord on multielectrode arrays (MEAs). All cultures showed spontaneous bursts of network activity. Blocking synaptic excitation with the AMPA receptor antagonist CNQX suppressed spontaneous network bursts and left asynchronous intrinsic activity at about 30% of the electrodes. Such intrinsic activity was completely blocked at all electrodes by both the INaP blocker riluzole as well as by the ICAN blocker flufenamic acid (FFA) and the more specific TRPM4 channel antagonist 9-phenanthrol. All three antagonists also suppressed spontaneous bursting completely and strongly reduced stimulus-evoked bursts. Also, FFA reduced repetitive spiking that was induced in single neurons by injection of depolarizing current pulses to few spikes. Other antagonists of unspecific cation currents or calcium currents had no suppressing effects on either intrinsic activity (gadolinium chloride) or spontaneous bursting (the TRPC channel antagonists clemizole and ML204 and the T channel antagonist TTA-P2). Combined patch-clamp and MEA recordings showed that Hb9 interneurons were activated by network bursts but could not initiate them. Together these findings suggest that both INaP through Na+-channels and ICAN through putative TRPM4 channels contribute to spontaneous intrinsic and repetitive spiking in spinal cord neurons and thereby to the generation of network bursts

Prescription Practices of Cannabinoids in Children with Cerebral Palsy Worldwide—A Survey of the Swiss Cerebral Palsy Registry.

Cannabinoids are prescribed to children with cerebral palsy despite limited evidence. We aimed to assess cannabinoid prescribing practices in children with cerebral palsy, focusing on indications, types of preparations used, and tolerability. Furthermore, we investigated how physicians acquire knowledge about cannabinoid medication. We asked physicians with expertise in the care of children with cerebral palsy about their prescribing practices for cannabinoids. Data were collected through an online survey, which was distributed by email. In addition to the demographic information of participants, we also inquired about the indications for the prescription of cannabinoids, experiences regarding efficacy, and observed side effects of the therapy. Seventy physicians from Europe, North America, and Australia completed the survey. Forty-seven participants were experienced in treating of children with cerebral palsy with cannabinoids. The most common indication was epilepsy (69%), followed by spasticity (64%) and pain (63%). The preparations and doses prescribed varied considerably. Half of the participants evaluated the effect of the cannabinoids as moderate. Twenty-nine physicians reported side effects, most frequently, drowsiness (26%), somnolence (19%), fatigue (13%), and diarrhea (13%). Despite the lack of evidence to date, cannabinoids are used to treat children with cerebral palsy in a wide variety of indications. Randomized controlled trials in this vulnerable patient group are therefore of utmost importance

Functional regeneration of intraspinal connections in a new in vitro model

Abstract—Regeneration in the adult mammalian spinal cord is limited due to intrinsic properties of mature neurons and a hostile environment, mainly provided by central nervous system myelin and reactive astrocytes. Recent results indicate that propriospinal connections are a promising target for intervention to improve functional recovery. To study this functional regeneration in vitro we developed a model consisting of two organotypic spinal cord slices placed adjacently on multi-electrode arrays. The electrodes allow us to record the spontaneously occurring neuronal activity, which is often organized in network bursts. Within a few days in vitro (DIV), these bursts become synchronized between the two slices due to the formation of axonal connections. We cut them with a scalpel at different time points in vitro and record the neuronal activity 3 weeks later. The functional recovery ability was assessed by calculating the percentage of synchronized bursts between the two slices. We found that cultures lesioned at a young age (7–9 DIV) retained the high regeneration ability of embryonic tissue. However, cultures lesioned at older ages (>19 DIV) displayed a distinct reduction of synchronized activity. This reduction was not accompanied by an inability for axons to cross the lesion site. We show that functional regeneration in these old cultures can be improved by increasing the intracellular cAMP level with Rolipram or by placing a young slice next to an old one directly after the lesion. We conclude that co-cultures of two spinal cord slices are an appropriate model to study functional regeneration of intraspinal connections

Effects of the COVID-19 Pandemic on Access to Education and Social Participation in Children and Adolescents with Duchenne Muscular Dystrophy in Switzerland.

BACKGROUND  Two-thirds of patients with Duchenne muscular dystrophy (DMD) have cognitive and neuropsychiatric problems. Concerning their quality of life, negative factors are the lack of qualifying education and social participation in sporting and leisure activities. Adapted assistance in education and participation in social life are thus important. During the coronavirus disease 2019 (COVID-19) pandemic, the pediatric population was less severely impacted by the disease, but by the restrictions associated. AIM  The aim of this study was to evaluate the impact of the COVID-19 pandemic regarding access to education and social participation for young patients with DMD in Switzerland. METHODS  We conducted a survey study from May to August 2021 assessing the impact of the COVID-19 pandemic on access to education and social participation in 8 to 18 years old patients with DMD in Switzerland. RESULTS  Of 60 sent surveys, 40 were returned and included. Mean age of participants was 13.5 years (±3.1 standard deviation); 23/40 of the participants were wheelchair bound, 21/40 attended a special school, and 19/40 a regular school. Of the 22/40 participants receiving assistance at school, 7/40 reported a change caused by the pandemic: for 5/7, the assistance was paused. Of the 12 boys and adolescents attending sporting activities, 10 had to suspend these. Nine attended other leisure activities; for 3/9, these activities were paused. CONCLUSION  The COVID-19 pandemic had direct effects on school assistance, sporting, and leisure activities in young patients with DMD in Switzerland. It is important to ensure that school assistance and leisure activities are rapidly resumed

Embryonic Cell Grafts in a Culture Model of Spinal Cord Lesion: Neuronal Relay Formation Is Essential for Functional Regeneration

Presently there exists no cure for spinal cord injury. However, transplantation of embryonic tissue into spinal cord lesions resulted in axon outgrowth across the lesion site and some functional recovery, fostering hope for future stem cell therapies. Although in vivo evidence for functional recovery is given, the exact cellular mechanism of the graft support remains elusive: either the grafted cells provide a permissive environment for the host tissue to regenerate itself or the grafts actually integrate functionally into the host neuronal network reconnecting the separated spinal cord circuits. We tested the two hypotheses in an in vitro spinal cord lesion model that is based on propagation of activity between two rat organotypic spinal cord slices in culture. Transplantation of dissociated cells from E14 rat spinal cord or forebrain re-established the relay of activity over the lesion site and, thus, provoked functional regeneration. Combining patch-clamp recordings from transplanted cells with network activity measurements from the host tissue on multi-electrode arrays we here show that neurons differentiate from the grafted cells and integrate into the host circuits. Optogenetic silencing of neurons developed from transplanted embryonic mouse forebrain cells provides clear evidence that they replace the lost neuronal connections to relay and synchronize activity between the separated spinal cord circuits. In contrast, transplantation of neurospheres induced neither the differentiation of mature neurons from the grafts nor an improvement of functional regeneration. Together these findings suggest, that the formation of neuronal relays from grafted embryonic cells is essential to re-connect segregated spinal cord circuits

Embryonic Stem Cell-Derived Neurons Grown on Multi-Electrode Arrays as a Novel In vitro Bioassay for the Detection of Clostridium botulinum Neurotoxins

Clostridium botulinum neurotoxins (BoNTs) are the most poisonous naturally occurring protein toxins known to mankind and are the causative agents of the severe and potentially life-threatening disease botulism. They are also known for their application as cosmetics and as unique bio-pharmaceuticals to treat an increasing number of neurological and non-neurological disorders. Currently, the potency of biologically active BoNT for therapeutic use is mainly monitored by the murine LD50-assay, an ethically disputable test causing suffering and death of a considerable number of mice. The aim of this study was to establish an in-vitro assay as an alternative to the widely used in-vivo mouse bioassay. We report a novel BoNT detection assay using mouse embryonic stem cell-derived neurons (mESN) cultured on multi-electrode arrays. After 21 days in culture, the mESN formed a neuronal network showing spontaneous bursting activity based on functional synapses and express the necessary target proteins for BoNTs. Treating cultures for 6 h with 16.6 pM of BoNT serotype A and incubation with 1.66 pM BoNT/A or 33 Units/ml of Botox® for 24 h lead to a significant reduction of both spontaneous network bursts and average spike rate. This data suggests that mESN cultured on multi-electrode arrays pose a novel, biologically relevant model that can be used to detect and quantify functional BoNT effects, thus accelerating BoNT research while decreasing animal use

Spiral Ganglion Neuron Explant Culture and Electrophysiology on Multi Electrode Arrays

Spiral ganglion neurons (SGNs) participate in the physiological process of hearing by relaying signals from sensory hair cells to the cochlear nucleus in the brain stem. Loss of hair cells is a major cause of sensory hearing loss. Prosthetic devices such as cochlear implants function by bypassing lost hair cells and directly stimulating SGNs electrically, allowing for restoration of hearing in deaf patients. The performance of these devices depends on the functionality of SGNs, the implantation procedure and on the distance between the electrodes and the auditory neurons. We hypothesized, that reducing the distance between the SGNs and the electrode array of the implant would allow for improved stimulation and frequency resolution, with the best results in a gapless position. Currently we lack in vitro culture systems to study, modify and optimize the interaction between auditory neurons and electrode arrays and characterize their electrophysiological response. To address these issues, we developed an in vitro bioassay using SGN cultures on a planar multi electrode array (MEA). With this method we were able to perform extracellular recording of the basal and electrically induced activity of a population of spiral ganglion neurons. We were also able to optimize stimulation protocols and analyze the response to electrical stimuli as a function of the electrode distance. This platform could also be used to optimize electrode features such as surface coatings

Evaluation of real-life outcome data of patients with spinal muscular atrophy treated with nusinersen in Switzerland

Spinal muscular atrophy (SMA) is an autosomal recessive disorder causing progressive proximal muscular, respiratory, and bulbar weakness. We present outcome data on motor function, ventilation, nutrition, and language development of SMA patients treated with nusinersen in Switzerland. This multicenter, observational study included 44 patients. At treatment initiation, after 2 months and then every 4 months we assessed motor function with the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), Hammersmith Functional Motor Scale expanded (HFMSE) and 6-Minute Walk Test (6MWT). At treatment initiation, patients were 0.1-44.6 years old, treatment duration ranged from 6 to 41 months. All 11 SMA type 1 children achieved higher CHOP-INTEND scores at the last assessment compared to treatment initiation, 4 acquired stable sitting. Six type 1 children were <18 months-old at treatment initiation. Two of them did not need ventilation or nutritional support at the last assessment; three had delayed language development and 3 articulation difficulties. 5/21 SMA type 2 patients achieved higher HFMSE scores. All ambulant type 3 patients showed a gain in the 6MWT. Nusinersen is an effective treatment, with gains in motor function occurring particularly in children and SMA type 1, but also in type 2 and 3, adolescents and adults

Evaluation of real-life outcome data of patients with spinal muscular atrophy treated with nusinersen in Switzerland.

Spinal muscular atrophy (SMA) is an autosomal recessive disorder causing progressive proximal muscular, respiratory, and bulbar weakness. We present outcome data on motor function, ventilation, nutrition, and language development of SMA patients treated with nusinersen in Switzerland. This multicenter, observational study included 44 patients. At treatment initiation, after 2 months and then every 4 months we assessed motor function with the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), Hammersmith Functional Motor Scale expanded (HFMSE) and 6-Minute Walk Test (6MWT). At treatment initiation, patients were 0.1-44.6 years old, treatment duration ranged from 6 to 41 months. All 11 SMA type 1 children achieved higher CHOP-INTEND scores at the last assessment compared to treatment initiation, 4 acquired stable sitting. Six type 1 children were <18 months-old at treatment initiation. Two of them did not need ventilation or nutritional support at the last assessment; three had delayed language development and 3 articulation difficulties. 5/21 SMA type 2 patients achieved higher HFMSE scores. All ambulant type 3 patients showed a gain in the 6MWT. Nusinersen is an effective treatment, with gains in motor function occurring particularly in children and SMA type 1, but also in type 2 and 3, adolescents and adults

Cohort profile: the Swiss Cerebral Palsy Registry (Swiss-CP-Reg) cohort study.

BACKGROUND Cerebral Palsy (CP) is a group of permanent disorders of movement and posture that follow injuries to the developing brain. It results in motor dysfunction and a wide variety of comorbidities like epilepsy; pain; speech, hearing and vision disorders; cognitive dysfunction; and eating and digestive difficulties. Central data collection is essential to the study of the epidemiology, clinical presentations, care, and quality of life of patients affected by CP. CP specialists founded the Swiss Cerebral Palsy Registry (Swiss-CP-Reg) in 2017. This paper describes the design, structure, aims and achievements of Swiss-CP-Reg and presents its first results. METHODS Swiss-CP-Reg records patients of any age diagnosed with CP who are born, are treated, or live in Switzerland. It collects data from medical records and reports, from questionnaires answered by patients and their families, and from data linkage with routine statistics and other registries. The registry contains information on diagnosis, clinical presentation, comorbidities, therapies, personal information, family history, and quality of life. RESULTS From August 2017 to August 2021, 546 participants (55% male, mean age at registration 8 years [interquartile range IQR: 5-12]), were enrolled in Swiss-CP-Reg. Most had been born at term (56%), were less than two years old at diagnosis (73%, median 18 months, IQR: 9-25), and were diagnosed with spastic CP (76%). Most (59%) live with a mild motor impairment (Gross Motor Function Classification System [GMFCS] level I or II), 12% with a moderate motor impairment (GMFCS level III), and 29% with a severe motor impairment (GMFCS level IV or V). In a subset of 170 participants, we measured intelligence quotient (IQ) and saw lower IQs with increasing GMFCS level. Swiss-CP-Reg has a strong interest in research, with four nested projects running currently, and many more planned. CONCLUSIONS Swiss-CP-Reg collects and exchanges national data on people living with CP to answer clinically relevant questions. Its structure enables retrospective and prospective data collection and knowledge exchange between experts to optimise and standardise treatment and to improve the health and quality of life of those diagnosed with CP in Switzerland