Symptomatic treatments of N-methyl-D-aspartate receptor encephalitis

Chronic social stress in early life can predispose mice to antisocial maltreating behavior

Purpose

In our previous study, we developed an assay system to evaluate antisocial maltreating behavior of conspecific mice using a perpetrator-victim paradigm. We also generated a mouse model for the maltreating behavior by mimicking child maltreatment or abuse. Here, we further investigate the antisocial behavior using anti-aggressive and antipsychotic drugs.

Methods

Model mice sequentially subjected to maternal separation (MS), social defeat (SD), and social isolation (SI) in that order (MS/SD/SI model) were subjected to a maltreating behavioral task. The MS/SD/SI mice were treated with oxytocin (OXY), clozapine (CLZ), haloperidol (HAL), and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). Western blotting and enzyme-linked immunosorbent assay were used for protein analysis.

Results

A substantial portion of the MS/SD/SI model mice (46% of males and 40% of females) showed a higher number of nose pokes than the control. OXY or 8-OH-DPAT treatment reduced the high number of nose pokes by the MS/SD/SI mice, whereas HAL increased it. CLZ did not affect the number of nose pokes by the MS/SD/SI mice. Interestingly, although the OXY level in the MS/SD/SI mice was similar to that in the control, the amount of OXY receptor was lower in the MS/SD/SI mice. The amount of 5-HT1A receptor was also decreased in the MS/SD/SI mice.

Conclusion

Chronic social stress in childhood might predispose a mouse to antisocial behavior. Our maltreating behavior assay system, including the MS/SD/SI model, is a good animal system for research on and drug screening for brain disorders associated with antisocial or psychotic behavior.

Topiramate dosage optimization for effective antiseizure management via population pharmacokinetic modeling

OBJECTIVE

Despite the suggested topiramate serum level of 5-20 mg/L, numerous institutions have observed substantial drug response at lower levels. We aim to investigate the correlation between topiramate serum levels, drug responsiveness, and adverse events to establish a more accurate and tailored therapeutic range.

METHODS

We retrospectively analyzed clinical data collected between January 2017 and January 2022 at Seoul National University Hospital. Drug responses to topiramate were categorized as "insufficient" or "sufficient" by reduction in seizure frequency ≥ 50%. A population pharmacokinetic model estimated serum levels from spot measurements. ROC curve analysis determined the optimal cutoff values.

RESULTS

A total of 389 epilepsy patients were reviewed having a mean dose of 178.4 ± 117.9 mg/day and the serum level, 3.9 ± 2.8 mg/L. Only 5.6% samples exhibited insufficient response, with a mean serum level of 3.6 ± 2.5 mg/L while 94.4% demonstrated sufficient response, with a mean 4.0 ± 2.8 mg/L, having no statistical significance. Among the 69 reported adverse events, logistic regression analysis identified a significant association between ataxia and serum concentration (p = 0.04), with an optimal cutoff value of 6.5 mg/L.

INTERPRETATION

This study proposed an optimal therapeutic concentration for topiramate based on patients' responsiveness to the drug and the incidence of adverse effects. We recommended serum levels below 6.5 mg/L to mitigate the risk of ataxia-related side effects while dose elevation was found unnecessary for suboptimal responders, as the drug's effectiveness plateaus at minimal doses.

Teratoma pathology and genomics in anti-NMDA receptor encephalitis

INTRODUCTION

Ovarian teratoma is a common occurrence in patients with anti-NMDA receptor encephalitis (NMDARe), and its removal is crucial for a favorable prognosis. However, the initial pathogenesis of autoimmunity in the encephalitic teratoma remains unclear. In this study, we aimed to investigate the genomic landscape and microscopic findings by comparing NMDARe-associated teratomas and non-encephalitic control teratomas.

MATERIALS AND METHODS

A prospective consecutive cohort of 84 patients with NMDARe was recruited from January 2014 to April 2020, and among them, patients who received teratoma removal surgery at Seoul National University Hospital were enrolled. We conducted a comparison of whole-exome sequencing data and pathologic findings between NMDARe-associated teratomas and control teratomas.

RESULTS

We found 18 NMDARe-associated teratomas from 15 patients and compared them with 17 non-encephalitic control teratomas. Interestingly, the genomic analysis revealed no significant differences in mutations between encephalitic and non-encephalitic teratomas. Pathologic analysis showed no discrepancies in terms of the presence of neuronal tissue and lymphocytic infiltration between the encephalitic teratomas (n = 14) and non-encephalitic teratomas (n = 18). However, rituximab-naïve encephalitic teratomas exhibited a higher frequency of germinal center formation compared to non-encephalitic teratomas (80% vs. 16.7%, P = 0.017). Additionally, rituximab-treated encephalitic teratomas demonstrated a reduced number of CD20+ cells and germinal centers in comparison to rituximab-naïve encephalitic teratomas (P = 0.048 and 0.023, respectively).

DISCUSSION

These results suggest that the initiation of immunopathogenesis in NMDARe-associated teratoma is not primarily attributed to intrinsic tumor mutations, but rather to immune factors present in the encephalitic patient group, ultimately leading to germinal center formation within the teratoma.

Chronic social stress during early development is involved in antisocial maltreatment behavior in mice

Purpose

Early-life stress can cause brain inflammation and affect social behavior in adulthood. In humans, maltreated (abused or neglected) children often exhibit antisocial behavior, including violent and sadistic behavior, in adulthood. However, it is unknown whether maltreatment behavior occurs in rodents. Here, we developed an assay system to evaluate conspecific maltreatment behavior in the mouse.

Methods

To assess maltreatment behavior, we devised a two-chamber apparatus separated by a transparent partition, in which one chamber was provided with a nose-poking hole that would trigger foot shocks onto the other. Lidocaine was used to inhibit neural activity in vivo. Brain oscillations were investigated by electroencephalograph. Enzyme-linked immunosorbent assay was used for protein assay. The mouse model was sequentially subjected to maternal separation (MS), social defeat (SD), and social isolation (SI) in that order (MS/SD/SI model).

Results

Inactivation of the anterior cingulate cortex and medial prefrontal cortex increased the level of nose-poking. Maltreatment behavior provoked changes in oxytocin, corticosterone, and brain-derived neurotrophic factor levels. MS/SD/SI mice exhibited more sustained nose-poking behavior during the experiment, resulting in increased foot shocks to the mouse in the opposite chamber. Abnormal brain oscillations were observed in the MS/SD/SI mice.

Conclusion

The MS/SD/SI model and maltreatment-behavior assay may be useful not only to study the relationship between social stress in childhood and antisocial behavior in adulthood, but also for study of etiology, pathology, or treatment for brain disorders, such as psychopathy.

Chronic social stress during early development elicits unique behavioral changes in adulthood

Purpose

Chronic social stress is known to induce inflammation in the brain, and early-life stress affects the brain and social behavior in adulthood. To study the relationship between social stress in childhood development and social behavior in adulthood, we subjected mice to a sequential early-life social stresses and characterized their adult behavioral phenotypes.

Methods

C57BL/6 mice were sequentially subjected to maternal separation (MS), social defeat (SD), and social isolation (SI) in that order. The body weights of the MS/SD/SI mice were measured. Behavioral tasks related to anxiety, depression, locomotion, learning/memory, and repetitive/compulsive-like behavior were conducted. Social behaviors suggesting sociability, social interaction, aggression, and social fear were investigated.

Results

MS/SD/SI mice weighed less than the control mice. At 7 and 8 weeks of age. These mice displayed normal behaviors in anxiety-, depression-, and learning/memory-related tasks, but they exhibited increased locomotor activity and a low level of repetitive/compulsive-like behavior. Notably, they exhibited increased social interaction, impaired empathy-related fear, reduced predator fear, and increased defensive aggressiveness.

Conclusion

Social stress during childhood development resulted in behavioral alterations, and MS/SD/SI mice generated by mimicking child abuse or maltreatment showed unique abnormalities in social behaviors. MS/SD/SI mice might be useful not only to study the relationship between social stress and brain inflammation but also psychosocial behaviors observed in individuals with brain disorders, such as psychopaths.