The microtubule-associated protein (MAP) TAU is mainly sorted into the axon of healthy brain neurons. Somatodendritic missorting of TAU is a pathological hallmark of many neurodegenerative diseases, including Alzheimer’s disease (AD). Cause, consequence and (patho)physiological mechanisms of TAU sorting and missorting are understudied, in part also because of the lack of readily available human neuronal model systems. The human neuroblastoma cell line SH-SY5Y is widely used for studying TAU physiology and TAU-related pathology in AD and related tauopathies. SH-SY5Y cells can be differentiated into neuron-like cells (SH-SY5Y-derived neurons) using various substances. This review evaluates whether SH-SY5Y-derived neurons are a suitable model for (i) investigating intracellular TAU sorting in general, and (ii) with respect to neuron subtype-specific TAU vulnerability. (I) SH-SY5Y-derived neurons show pronounced axodendritic polarity, high levels of axonally localized TAU protein, expression of all six human brain isoforms and TAU phosphorylation similar to the human brain. As SH-SY5Y cells are highly proliferative and readily accessible for genetic engineering, stable transgene integration and leading-edge genome editing are feasible. (II) SH-SY5Y-derived neurons display features of subcortical neurons early affected in many tauopathies. This allows analyzing brain region-specific differences in TAU physiology, also in the context of differential vulnerability to TAU pathology. However, several limitations should be considered when using SH-SY5Y-derived neurons, e.g., the lack of clearly defined neuronal subtypes, or the difficulty of mimicking age-related tauopathy risk factors in vitro. In brief, this review discusses the suitability of SH-SY5Y-derived neurons for investigating TAU (mis)sorting mechanisms and neuron-specific TAU vulnerability in disease paradigms.

Status epilepticus (SE) is a common indication for neurocritical care and can be refractory to standard measures. Refractory SE (RSE) is associated with high morbidity and mortality. Unconventional therapies may be utilized in certain cases, including therapeutic hypothermia (TH), bumetanide, and the ketogenic diet. However, the literature describing the use of such therapies in RSE is limited. Details of a case of TH for RSE in an infant with malignant migrating partial seizures of infancy were obtained from the medical record. A 4-month-old child developed SE that was refractory to treatment with concurrent midazolam, phenobarbital, fosphenytoin, topiramate, levetiracetam, folinic acid, and pyridoxal-5-phosphate. This led to progressive implementation of three unconventional therapies: TH, bumetanide, and the ketogentic diet. Electrographic seizures ceased for the entirety of a 43-hour period of TH with a target rectal temperature of 33.0°C–34.0°C. No adverse effects of hypothermia were noted other than a single episode of asymptomatic hypokalemia. Seizures recurred 10 hours after rewarming was begun and did not abate with reinstitution of hypothermia. No effect was seen with administration of bumetanide. Seizures were controlled long-term within 48 hours of institution of the ketogenic diet. TH and the ketogenic diet may be effective for treating RSE in children.

Epigenetic mechanisms are emerging key players for the regulation of brain function, synaptic activity, and the formation of neuronal engrams in health and disease. As one important epigenetic mechanism of transcriptional control, DNA methylation was reported to distinctively modulate synaptic activity in excitatory and inhibitory cortical neurons in mice. Since DNA methylation signatures are responsive to neuronal activity, DNA methylation seems to contribute to the neuron’s capacity to adapt to and integrate changing activity patterns, being crucial for the plasticity and functionality of neuronal circuits. Since most studies addressing the role of DNA methylation in the regulation of synaptic function were conducted in mice or murine neurons, we here asked whether this functional implication applies to human neurons as well. To this end, we performed calcium imaging in human induced pluripotent stem cell (iPSC)-derived excitatory cortical neurons forming synaptic contacts and neuronal networks in vitro. Treatment with DNMT1 siRNA that diminishs the expression of the DNA (cytosine-5)-methyltransferase 1 (DNMT1) was conducted to investigate the functional relevance of DNMT1 as one of the main enzymes executing DNA methylations in the context of neuronal activity modulation. We observed a lowered proportion of actively firing neurons upon DNMT1-knockdown in these iPSC-derived excitatory neurons, pointing to a correlation of DNMT1-activity and synaptic transmission. Thus, our experiments suggest that DNMT1 decreases synaptic activity of human glutamatergic neurons and underline the relevance of epigenetic regulation of synaptic function also in human excitatory neurons.

Brain injury is the leading cause of death in our pediatric ICU [Au et al. Crit Care Med 36:A128, 2008]. Clinical care for brain injury remains largely supportive. Therapeutic hypothermia has been shown to be effective in improving neurological outcome after adult ventricular-arrhythmia-induced cardiac arrest and neonatal asphyxia, and is under investigation as a neuroprotectant after cardiac arrest and traumatic brain injury in children in our ICU and other centers. To induce hypothermia in children comatose after cardiac arrest we target 32–34°C using cooling blankets and intravenous iced saline as primary methods for induction, for 24–72 h duration with vigilant re-warming. The objective of this article is to share our hypothermia protocol for cooling children with acute brain injury.

Background: Pediatric acute liver failure (PALF) is a public heath burden, often requiring prolonged hospitalization and liver transplantation. Hepatic encephalopathy (HE) is a complication of PALF with limited diagnostic tools to predict outcomes. Serum neurological markers (neuron‐specific enolase, S100β, and myelin basic protein) can be elevated in traumatic or ischemic brain injury. We hypothesized that these neuromarkers would be associated with the development of HE in PALF.Methods: PALF study participants enrolled between May 2012 and December 2014 by 12 participating centers were the subjects of this analysis. Daily HE assessments were determined by study investigators. Neurological and inflammatory markers were measured using enzyme‐linked immunosorbent assay and MILLIPLEX techniques, respectively. To model encephalopathy, these markers were log₂ transformed and individually examined for association with HE using a generalized linear mixed model with a logit link and random intercept.Results: Eighty‐two children had neurological and inflammatory marker levels and HE assessments recorded, with the majority having assessments for 3 days during their illness. An indeterminate diagnosis (29%) was most common and the median age was 2.9 years. Significant associations were observed for HE with S100β (odds ratio 1.16, 95% confidence interval [1.03–1.29], P = 0.04) and IL‐6 (odds ratio 1.24 [1.11–1.38], P = 0.006).Conclusions: Serum S100β and IL‐6 are associated with HE in children with PALF. Measuring these markers may assist in assessing neurological injury in PALF, impacting clinical decisions.