Exogenous and endogenous formaldehyde-induced DNA damage in the aging brain: mechanisms and implications for brain diseases.

Exogenous gaseous formaldehyde (FA) is recognized as a significant indoor air pollutant due to its chemical reactivity and documented mutagenic and carcinogenic properties, particularly in its capacity to damage DNA and impact human health. Despite increasing attention on the adverse effects of exogenous FA on human health, the potential detrimental effects of endogenous FA in the brain have been largely neglected in current research. Endogenous FA have been observed to accumulate in the aging brain due to dysregulation in the expression and activity of enzymes involved in FA metabolism. Surprisingly, excessive FA have been implicated in the development of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and brain cancers. Notably, FA has the ability to not only initiate DNA double strand breaks but also induce the formation of crosslinks of DNA-DNA, DNA-RNA, and DNA-protein, which further exacerbate the progression of these brain diseases. However, recent research has identified that FA-resistant gene exonuclease-1 (EXO1) and FA scavengers can potentially mitigate FA toxicity, offering a promising strategy for mitigating or repairing FA-induced DNA damage. The present review offers novel insights into the impact of FA metabolism on brain ageing and the contribution of FA-damaged DNA to the progression of neurological disorders.

Baclofen and Tizanidine Adverse Effects Observed Among Community-Dwelling Adults Above the Age of 50 Years: A Systematic Review.

OBJECTIVE: This review highlights adverse effects of baclofen and tizanidine in older community-dwelling adults. DATA SOURCES: A literature search was conducted, including search terms of "adverse effect," "baclofen," "elderly," "falls," "fractures," and "tizanidine." Studies were included if they described community-dwelling adults aged 50 years and older who received oral baclofen or tizanidine. The Federal Drug Administration Adverse Event Reporting System (FAERS) data were compiled for adverse effect incidence. STUDY SELECTION AND DATA EXTRACTION: The literature search was completed in July 2019 and updated in June 2023. Reviews performed by 2 independent reviewers yielded 15 records. FAERS identified 486 (baclofen) and 305 (tizanidine) adverse effects of interest. DATA SYNTHESIS: Two retrospective cohort studies evaluating baclofen use in older adults showed increased hospitalizations for encephalopathy in chronic kidney disease (7.2% vs 0.1%) and end-stage renal disease (daily dose 20 mg or more; relative risk [RR] 19.8, 95% CI = [14.0-28.0]). Other articles were case reports; 10 articles reported dyskinesias, encephalopathy or disorientation, and drowsiness associated with baclofen, and 5 articles reported bradycardia and/or hypotension with tizanidine. The FAERS Public Dashboard revealed 12.1% and 28.7% overall incidence of adverse effects of interest, with a 27.8% and 29.2% incidence of falls for baclofen and tizanidine, respectively. Baclofen and tizanidine are associated with concerning adverse effects in older adults. Alternative agents should be considered, but, if necessary, providers should start at lower doses and increase slowly. CONCLUSIONS: This review highlights the importance of using baclofen and tizanidine with caution in older adults.

A Pediatric Case of B Cell Precursor ALL With Blinatumomab-associated Encephalopathy.

Blinatumomab is a CD3/CD19-directed bispecific T-cell engager used to treat relapsed or refractory B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Although blinatumomab has shown efficacy, it can cause serious adverse events, including cytokine release syndrome and neurological events. Among the neurological events, encephalopathy is rare, and knowledge is lacking. Herein, we present a pediatric case of blinatumomab-associated encephalopathy that initially presented with refractory convulsions and later developed into a cerebral infarction. The patient experienced prolonged paralysis and increased brain damage.

Dissecting the networks underlying diverse brain disorders after prenatal glucocorticoid overexposure.

New human life begins in the uterus in a period of both extreme plasticity and sensitivity to environmental disturbances. The fetal stage is also a vital period for central nervous system development, with experiences at this point profoundly and permanently shaping brain structure and function. As such, some brain disorders may originate in utero. Glucocorticoids, a class of essential stress hormones, play indispensable roles in fetal development, but overexposure may have lasting impacts on the brain. In this review, we summarize data from recent clinical and non-clinical studies regarding alterations in fetal brains due to prenatal glucocorticoid overexposure that are associated with nervous system disorders. We discuss relevant changes to brain structure and cellular functions and explore the underlying molecular mechanisms. In addition, we summarize factors that may cause differential outcomes between varying brain regions, and outline clinically feasible intervention strategies that are expected to minimize negative consequences arising from fetal glucocorticoid overexposure. Finally, we highlight the need for experimental evidence aided by new technologies to clearly determine the effects of excessive prenatal glucocorticoid exposure. This review consolidates diverse findings to help researchers better understand the relationship between the prenatal glucocorticoid overexposure and the effects it has on various fetal brain regions, promoting further development of critical intervention strategies.

Hyperammonemic encephalopathy after tyrosine kinase inhibitors: A literature review and a case example.

OBJECTIVE: To review the evidence of uncommon but fatal adverse event of hyperammonemic encephalopathy by tyrosine kinase inhibitors (TKI) and the possible mechanisms underlying this condition and to describe the case of a patient that developed drug-induced hyperammonemic encephalopathy related to TKI. DATA SOURCES: Literature search of different databases was performed for studies published from 1 January 1992 to 7 May 2023. The search terms utilized were hyperammonemic encephalopathy, TKI, apatinib, pazopanib, sunitinib, imatinib, sorafenib, regorafenib, trametinib, urea cycle regulation, sorafenib, carbamoyl-phosphate synthetase 1, ornithine transcarbamylase, argininosuccinate synthetase, argininosuccinate lyase, arginase 1, Mitogen activated protein kinases (MAPK) pathway and mTOR pathway, were used individually search or combined. DATA SUMMARY: Thirty-seven articles were included. The articles primarily focused in hyperammonemic encephalopathy case reports, management of hyperammonemic encephalopathy, urea cycle regulation, autophagy, mTOR and MAPK pathways, and TKI. CONCLUSION: Eighteen cases of hyperammonemic encephalopathy were reported in the literature from various multitargeted TKI. The mechanism of this event is not well-understood but some authors have hypothesized vascular causes since some of TKI are antiangiogenic, however our literature review shows a possible relationship between the urea cycle and the molecular inhibition exerted by TKI. More preclinical evidence is required to unveil the biochemical mechanisms responsible involved in this process and clinical studies are necessary to shed light on the prevalence, risk factors, management and prevention of this adverse event. It is important to monitor neurological symptoms and to measure ammonia levels when manifestations are detected.

Association of non-steroidal anti-inflammatory drug use with encephalopathy development: An analysis using the United States Food and Drug Administration Adverse Event Reporting System (FAERS) and Japanese Adverse Drug Event Report (JADER) databases.

Encephalopathy is the most severe complication of various common infections, including influenza and herpes, and it often results in death or severe neurological disability. The risk factors for viral encephalopathy include non-steroidal anti-inflammatory drug (NSAID) use; however, studies on NSAID-related encephalopathy are limited. In this study, we aimed to investigate the characteristics of NSAID-related encephalopathy. We investigated the incidence of NSAID-related encephalopathy using data from the United States Food and Drug Administration Adverse Event Reporting System (FAERS) and Japanese Adverse Drug Event Report (JADER) databases containing reports on spontaneous adverse effects (AEs) published by the Pharmaceuticals and Medical Devices Agency. We used these databases to detect AEs based on reported odds ratios. By separating suspicious drugs, concomitant drugs, and drug interactions involving NSAIDs, we investigated the relationship between encephalopathy pathology and AEs of NSAIDs. Significant encephalopathy signals were detected for loxoprofen and etodolac in the FAERS database and loxoprofen in the JADER database. In the JADER database, significant encephalopathy signals in loxoprofen-treated patients were detected in 70-79-year-old, ≥80-year-old, influenza viral infection, and herpes virus infection groups. Significant encephalopathy signals in patients with herpes virus infection were detected in the ≥80-year-old and loxoprofen-treated groups. Regarding the involvement of loxoprofen in the development of encephalopathy, the JADER database listed loxoprofen as a suspect drug, without indicating any concomitant drug interactions. In conclusion, our findings suggest that loxoprofen and etodolac may be associated with viral encephalopathy. Accordingly, prudence is recommended when using loxoprofen in older individuals with viral infections.

[Clinical features of acyclovir encephalopathy without acute kidney injury].

INTRODUCTION: Few reports have described acyclovir (ACV) encephalopathy without acute kidney injury (AKI). OBJECTIVE: This study clarified the clinical features of ACV encephalopathy without AKI compared to that with AKI. METHODS: Creatinine (Cre) levels were measured on admission. After admission, Cre was measured in a timely manner for the first seven hospital days. The minimum Cre level in these measurements was then determined. ACV encephalopathy was defined when two criteria were met: 1) neurological symptoms appeared after valacyclovir (VACV) administration, and 2) neurological symptoms improved after VACV discontinuation. AKI was defined when the Cre level on admission was >1.5 times higher than the minimum Cre level. The subjects were divided into AKI and non-AKI groups based on these findings. RESULTS: Eighteen patients had ACV encephalopathy (5 males, mean age 81.3±5.5 years old). All patients were prescribed VACV 3,000 mg/day. The minimum Cre was 1.93±1.76 mg/dL. AKI occurred in 10 (56.6%) patients. VACV was discontinued in all patients, and emergency hemodialysis treatment was administered in 10 (55.6%) patients. All patients recovered. Compared to the AKI group, the non-AKI group had a lower history of taking a Ca-blocker (33.3% vs 80.0%, p=0.092), a lower rate of emergency dialysis (16.9% vs 70.0%, p=0.059) and a longer time to clinical improvement (3.67±1.86 vs 2.20±0.63 days, p=0.073). CONCLUSION: ACV encephalopathy without AKI is characterized by a low rate of emergency dialysis, which may be linked to a prolonged duration of symptoms.

Repeated blood-brain barrier opening with an implantable ultrasound device for delivery of albumin-bound paclitaxel in patients with recurrent glioblastoma: a phase 1 trial.

BACKGROUND: Low-intensity pulsed ultrasound with concomitant administration of intravenous microbubbles (LIPU-MB) can be used to open the blood-brain barrier. We aimed to assess the safety and pharmacokinetics of LIPU-MB to enhance the delivery of albumin-bound paclitaxel to the peritumoural brain of patients with recurrent glioblastoma. METHODS: We conducted a dose-escalation phase 1 clinical trial in adults (aged ≥18 years) with recurrent glioblastoma, a tumour diameter of 70 mm or smaller, and a Karnofsky performance status of at least 70. A nine-emitter ultrasound device was implanted into a skull window after tumour resection. LIPU-MB with intravenous albumin-bound paclitaxel infusion was done every 3 weeks for up to six cycles. Six dose levels of albumin-bound paclitaxel (40 mg/m2, 80 mg/m2, 135 mg/m2, 175 mg/m2, 215 mg/m2, and 260 mg/m2) were evaluated. The primary endpoint was dose-limiting toxicity occurring during the first cycle of sonication and albumin-bound paclitaxel chemotherapy. Safety was assessed in all treated patients. Analyses were done in the per-protocol population. Blood-brain barrier opening was investigated by MRI before and after sonication. We also did pharmacokinetic analyses of LIPU-MB in a subgroup of patients from the current study and a subgroup of patients who received carboplatin as part of a similar trial (NCT03744026). This study is registered with ClinicalTrials.gov, NCT04528680, and a phase 2 trial is currently open for accrual. FINDINGS: 17 patients (nine men and eight women) were enrolled between Oct 29, 2020, and Feb 21, 2022. As of data cutoff on Sept 6, 2022, median follow-up was 11·89 months (IQR 11·12-12·78). One patient was treated per dose level of albumin-bound paclitaxel for levels 1 to 5 (40-215 mg/m2), and 12 patients were treated at dose level 6 (260 mg/m2). A total of 68 cycles of LIPU-MB-based blood-brain barrier opening were done (median 3 cycles per patient [range 2-6]). At a dose of 260 mg/m2, encephalopathy (grade 3) occurred in one (8%) of 12 patients during the first cycle (considered a dose-limiting toxicity), and in one other patient during the second cycle (grade 2). In both cases, the toxicity resolved and treatment continued at a lower dose of albumin-bound paclitaxel, with a dose of 175 mg/m2 in the case of the grade 3 encephalopathy, and to 215 mg/m2 in the case of the grade 2 encephalopathy. Grade 2 peripheral neuropathy was observed in one patient during the third cycle of 260 mg/m2 albumin-bound paclitaxel. No progressive neurological deficits attributed to LIPU-MB were observed. LIPU-MB-based blood-brain barrier opening was most commonly associated with immediate yet transient grade 1-2 headache (12 [71%] of 17 patients). The most common grade 3-4 treatment-emergent adverse events were neutropenia (eight [47%]), leukopenia (five [29%]), and hypertension (five [29%]). No treatment-related deaths occurred during the study. Imaging analysis showed blood-brain barrier opening in the brain regions targeted by LIPU-MB, which diminished over the first 1 h after sonication. Pharmacokinetic analyses showed that LIPU-MB led to increases in the mean brain parenchymal concentrations of albumin-bound paclitaxel (from 0·037 µM [95% CI 0·022-0·063] in non-sonicated brain to 0·139 µM [0·083-0·232] in sonicated brain [3·7-times increase], p<0·0001) and carboplatin (from 0·991 µM [0·562-1·747] in non-sonicated brain to 5·878 µM [3·462-9·980] µM in sonicated brain [5·9-times increase], p=0·0001). INTERPRETATION: LIPU-MB using a skull-implantable ultrasound device transiently opens the blood-brain barrier allowing for safe, repeated penetration of cytotoxic drugs into the brain. This study has prompted a subsequent phase 2 study combining LIPU-MB with albumin-bound paclitaxel plus carboplatin (NCT04528680), which is ongoing. FUNDING: National Institutes of Health and National Cancer Institute, Moceri Family Foundation, and the Panattoni family.

Valproate-Associated Hyperammonemic Encephalopathy: Clinical Correlates and Management Strategies in a Tertiary Care Center.

BACKGROUND: Common adverse effects of valproate include sedation, tremor, gastrointestinal effects, and weight gain. Valproate-associated hyperammonemic encephalopathy (VHE) is an uncommon adverse effect of valproate therapy, which includes symptoms such as tremors, ataxia, seizures, confusion, sedation and coma. We report clinical features and management of 10 cases of VHE in a tertiary care center. METHODS: In a retrospective chart review of case records from January 2018 to June 2021, 10 patients with VHE were identified and included in this case series. The data collected include demographic information, psychiatric diagnosis, comorbidities, liver function tests, serum ammonia and serum valproate levels, dosages and duration of valproate, management of hyperammonemia including dosage variations, discontinuation, adjuvant drugs used, and whether rechallenge was done. RESULTS: The most common indication of starting valproate was bipolar disorder (n = 5). All the patients had more than one physical comorbidity and risk factors for developing hyperammonemia. Seven patients received valproate at a dose higher than 20 mg/kg. The duration of valproate use varied from 1 week to 19 years before developing VHE. Dose reduction or discontinuation and lactulose were the most common management strategies used. All 10 patients improved. Among the 7 patients in whom valproate was discontinued, for 2 patients valproate was reinitiated in inpatient care with careful monitoring and was found to be well tolerated. CONCLUSIONS: This case series highlights the need for a high index of suspicion for VHE as it is frequently associated with a delayed diagnosis and recovery in psychiatric settings. Screening for risk factors and serial monitoring may allow earlier diagnosis and management.

Neuropsychological, neuroimaging and autopsy findings of butane encephalopathy.

BACKGROUND: Butane is an aliphatic hydrocarbon used in various commercial products. While numerous reports of sudden cardiac-related deaths from butane inhalation have been described, butane-associated acute encephalopathy has rarely been reported. CASE PRESENTATION: A 38-year-old man presented with cognitive dysfunction after butane gas inhalation. Neuropsychological test results showed impairments in verbal and visual memory, and frontal executive function. Diffusion weighted MRI revealed symmetric high-signal changes in the bilateral hippocampus and globus pallidus. FDG-PET demonstrated decreased glucose metabolism in the bilateral precuneus and occipital areas and the left temporal region. At the 8-month follow-up, he showed still significant deficits in memory and frontal functions. Diffuse cortical atrophy with white matter hyperintensities and extensive glucose hypometabolism were detected on follow-up MRI and FDG-PET, respectively. Brain autopsy demonstrated necrosis and cavitary lesions in the globus pallidus. CONCLUSIONS: Only a few cases of butane encephalopathy have been reported to date. Brain lesions associated with butane encephalopathy include lesions in the bilateral thalamus, insula, putamen, and cerebellum. To the best of our knowledge, this is the first report on bilateral hippocampal and globus pallidal involvement in acute butane encephalopathy. The pathophysiology of central nervous system complications induced by butane intoxication is not yet fully understood. However, the direct toxic effects of butane or anoxic injury secondary to cardiac arrest or respiratory depression have been suggested as possible mechanisms of edematous changes in the brain after butane intoxication.

Flow diagram of the differential diagnosis and clinical decision making in a rare case of contrast-induced encephalopathy following cardiac catheterization: a case report.

BACKGROUND: Contrast-induced encephalopathy (CIE) is considered as an uncommon complication following cardiac catheterization. Due to the varied manifestations, CIE has no formal diagnostic criteria. In fact, the incidence of CIE may be greatly underestimated because of the difficulty in its differential diagnosis with other cerebrovascular complications. Thus, making a flow diagram according to patients' clinical symptoms and examinations after cardiac catheterization to help clinicians diagnose CIE is important and needed. CASE PRESENTATION: In this report, we describe a case of probable CIE in a 66-year-old Chinese man with hypertension who underwent cardiac catheterization with stents placement in the bifurcation lesion, during which 80 ml iopromide contrast was used. About 2 h following the procedure, the patient lost his consciousness suddenly and suffered from a status epilepticus. Malignant arrhythmias were not found through continuous electrocardiogram monitoring, but mild ST-segment elevation was displayed in leads I and aVL. The echocardiography, plasma glucose and electrolyte levels were normal. Emergency re-angiography with percutaneous transluminal coronary angioplasty was performed in the culprit lesion, which involved 60 ml iopromide contrast. However, the patient remained unconsciousness and epilepticus. Non-contrast computed tomography (CT) of the head showed cortical and subarachnoid enhancement as well as prolonged retention of contrast media in the middle cerebral artery. With supportive treatment of intravenous hydration, sedative and dehydrant, the patient recovered 3 h later and finally discharged without any neurological deficits. CONCLUSIONS: CIE is an acute reversible encephalopathy induced by contrast media. It is exceptionally challenging to make the diagnosis of CIE following cardiac catheterization since there is a lack of consensus on the definition of CIE. Via this case we reviewed the related literatures, through which a flow diagram of the differential diagnosis and clinical decision making was given, which could help to differentiate CIE from other neurological complications following cardiac catheterization.

The Potential Benefits of Quercetin for Brain Health: A Review of Anti-Inflammatory and Neuroprotective Mechanisms.

Neuroinflammation is a critical factor in developing and progressing numerous brain diseases, including neurodegenerative diseases. Chronic or excessive neuroinflammation can lead to neurotoxicity, causing brain damage and contributing to the onset and progression of various brain diseases. Therefore, understanding neuroinflammation mechanisms and developing strategies to control them is crucial for treating brain diseases. Studies have shown that neuroinflammation plays a vital role in the progression of neurodegenerative diseases, such as Alzheimer's (AD) and Parkinson's (PD), and stroke. Additionally, the effects of PM2.5 pollution on the brain, including neuroinflammation and neurotoxicity, are well-documented. Quercetin is a flavonoid, a plant pigment in many fruits, vegetables, and grains. Quercetin has been studied for its potential health benefits, including its anti-inflammatory, antioxidant, and anti-cancer properties. Quercetin may also have a positive impact on immune function and allergy symptoms. In addition, quercetin has been shown to have anti-inflammatory and neuroprotective properties and can activate AMP-activated protein kinase (AMPK), a cellular energy sensor that modulates inflammation and oxidative stress. By reducing inflammation and protecting against neuroinflammatory toxicity, quercetin holds promise as a safe and effective adjunctive therapy for treating neurodegenerative diseases and other brain disorders. Understanding and controlling the mechanisms of NF-κB and NLRP3 inflammasome pathways are crucial for preventing and treating conditions, and quercetin may be a promising tool in this effort. This review article aims to discuss the role of neuroinflammation in the development and progression of various brain disorders, including neurodegenerative diseases and stroke, and the impact of PM2.5 pollution on the brain. The paper also highlights quercetin's potential health benefits and anti-inflammatory and neuroprotective properties.

Cefepime Induced Encephalopathy in a Non-dialysis Dependent Chronic Kidney Disease Patient: A Case Report.

Cefepime is a frequently used fourth-generation cephalosporin antibiotic for a wide variety of infections. Toxic levels of this drug can cause neurological complications. The most common neurological adverse event of cefepime is headache and lightheadedness. Here, we presented a case of cefepime induced encephalopathy in a 57-year-old female patient with acute on chronic kidney disease. With an accurate diagnosis that requires a high index of clinical suspicion, prompt management was instituted. She had full resolution of symptoms following discontinuation of the medication and also emergent dialysis.

[A case of irreversible metronidazole encephalopathy during liver abscess treatment].

Metronidazole (MNZ) is a widely used drug for protozoan and anaerobic infections. The continuous use of MNZ causes various neurological symptoms, such as cerebellar ataxia, visual disturbance, vestibulocochlear symptoms, gait disturbance, dysarthria, and epileptic seizures of unknown cause, named MNZ-induced encephalopathy (MIE), in rare cases. MIE is a reversible disease that often improves within a few days of MNZ discontinuation, but irreversible neurological symptoms rarely remain. Herein, we report a case of MIE that developed during MNZ administration for a liver abscess, causing prolonged unconsciousness and death even after drug discontinuation. An 85-year-old female patient complained of fever, elevated liver enzymes, and a multifocal abscess in the right hepatic lobe, as seen on computed tomography. Percutaneous transhepatic abscess drainage and antibiotic therapy were initiated. The causative agent of the liver abscess could not be identified, thus meropenem was started, which demonstrated no inflammation improvement, thus oral MNZ was added. The inflammation recurred when MNZ was discontinued, and the patient continued taking MNZ. Vomiting, upper limb tremors, consciousness disturbance, and convulsions appeared on day 46 (total dose of MNZ 73.5mg), and the patient was hospitalized. T2-weighted, diffusion-weighted, and FLAIR head magnetic resonance imaging (MRI) revealed symmetrical abnormal high-signal areas in the cerebellar dentate nucleus, corpus callosum, cerebral white matter, and periventricular areas. MIE was diagnosed based on the patient's course and MRI images, and MNZ was discontinued. The patient continued to suffer from impaired consciousness and convulsions after MNZ discontinuation and died due to aspiration pneumonia. Suggestively, MIE development is related to long-term MNZ administration, poor nutrition, liver disease, underlying diseases (such as advanced cancer), and serious complications. A systematic review of MIE cases revealed that 4.8-5.9% of the patients demonstrated little improvement of symptoms after MNZ discontinuation, and some deaths were reported. Patients with poor prognosis were often suffering from impaired consciousness and convulsions. Furthermore, impaired consciousness was the most common residual symptom. Abnormal signals in characteristic areas, such as the dentate nucleus cerebri and corpus callosum, on head MRI are useful for MIE diagnosis, especially in patients with abnormal findings in the cerebral white matter, which is associated with a poor prognosis. We should pay close attention to the onset of MIE when MNZ is administered.

[A severe, reversible encephalopathy after prolonged use of valproic acid]. / Ernstige, reversibele encefalopathie bij langdurig valproïnezuurgebruik.

Valproic acid is an effective mood stabilizer, registered for the treatment of bipolar disorder and epilepsy. Side effects of valproic acid are transient and generally well tolerated. A rare side effect is a valproic acid-induced encephalopathy. We saw a case of valproic acid-induced encephalopathy without hyperammonemia in a 71-year-old woman. She had used valproic acid as a mood stabilizer over the course of 16 years for a bipolar I disorder. The following clinical symptoms were observed: staring eye contact, somnolence, disorientation, hypotenacity, bradyfrenia, mutism and akathisia. Severe extrapyramidal symptoms were observed during neurological examination as well as hyperreflexia, a snoutreflex on both sides and a right-sided palmomental reflex. After cessation of the valproic acid, her symptoms disappeared completely. Based on this case report, we discuss the clinical aspects, pathophysiology, recognition and treatment of valproic acid-induced encephalopathy, both with and without hyperammonemia.

A unique cerebellar pattern of microglia activation in a mouse model of encephalopathy of prematurity.

Preterm infants often show pathologies of the cerebellum, which are associated with impaired motor performance, lower IQ and poor language skills at school ages. Using a mouse model of inflammation-induced encephalopathy of prematurity driven by systemic administration of pro-inflammatory IL-1ß, we sought to uncover causes of cerebellar damage. In this model, IL-1ß is administered between postnatal day (P) 1 to day 5, a timing equivalent to the last trimester for brain development in humans. Structural MRI analysis revealed that systemic IL-1ß treatment induced specific reductions in gray and white matter volumes of the mouse cerebellar lobules I and II (5% false discovery rate [FDR]) from P15 onwards. Preceding these MRI-detectable cerebellar volume changes, we observed damage to oligodendroglia, with reduced proliferation of OLIG2+ cells at P10 and reduced levels of the myelin proteins myelin basic protein (MBP) and myelin-associated glycoprotein (MAG) at P10 and P15. Increased density of IBA1+ cerebellar microglia were observed both at P5 and P45, with evidence for increased microglial proliferation at P5 and P10. Comparison of the transcriptome of microglia isolated from P5 cerebellums and cerebrums revealed significant enrichment of pro-inflammatory markers in microglia from both regions, but cerebellar microglia displayed a unique type I interferon signaling dysregulation. Collectively, these data suggest that perinatal inflammation driven by systemic IL-1ß leads to specific cerebellar volume deficits, which likely reflect oligodendrocyte pathology downstream of microglial activation. Further studies are now required to confirm the potential of protective strategies aimed at preventing sustained type I interferon signaling driven by cerebellar microglia as an important therapeutic target.

Cefepime-induced neurotoxicity: systematic review.

BACKGROUND: Cefepime-induced neurotoxicity (CIN) has been well acknowledged among clinicians, although there are no clear diagnostic criteria or specific laboratory testing to help with its diagnosis. We aimed to summarize the existing evidence regarding CIN and provide future agendas for research. METHODS: Following the PRISMA Extension for Scoping Reviews, we searched MEDLINE and Embase for all peer-reviewed articles using keywords including 'cefepime', 'neurotoxicity', 'encephalopathy' and 'seizure', from their inception to 20 January 2022. RESULTS: We included 92 articles, including 23 observational studies and 69 cases from case reports and case series, in the systematic review. Among 119 patients with CIN, 23.5% were in the ICU at the time of diagnosis and nearly 90% of the cases showed renal dysfunction.Cefepime overdoses were described in 41%. The median latency period of developing CIN from cefepime initiation was 4 days, and about 12% developed CIN during empirical treatment. CIN patients commonly manifested altered mental status (93%), myoclonus (37%) and non-convulsive seizure epilepticus (28%). A serum cefepime trough level of >20 mg/L would put patients at risk for CIN. CIN-related symptoms were ameliorated in 97.5% by dose reduction or discontinuation of cefepime, with median time to improvement of 3 days. No CIN-associated deaths were reported. CONCLUSIONS: This systematic review summarizes the current evidence and characteristics of CIN. In the current situation where there are no CIN diagnostic criteria and the drug monitoring platform is not routinely available, candidates for cefepime should be carefully selected. Also, based on these findings, it needs to be appropriately dosed to avoid the development of CIN.

Slack K+ channels attenuate NMDA-induced excitotoxic brain damage and neuronal cell death.

The neuronal Na+ -activated K+ channel Slack (aka Slo2.2, KNa 1.1, or Kcnt1) has been implicated in setting and maintaining the resting membrane potential and defining excitability and firing patterns, as well as in the generation of the slow afterhyperpolarization following bursts of action potentials. Slack activity increases significantly under conditions of high intracellular Na+ levels, suggesting this channel may exert important pathophysiological functions. To address these putative roles, we studied whether Slack K+ channels contribute to pathological changes and excitotoxic cell death caused by glutamatergic overstimulation of Ca2+ - and Na+ -permeable N-methyl-D-aspartic acid receptors (NMDAR). Slack-deficient (Slack KO) and wild-type (WT) mice were subjected to intrastriatal microinjections of the NMDAR agonist NMDA. NMDA-induced brain lesions were significantly increased in Slack KO vs WT mice, suggesting that the lack of Slack renders neurons particularly susceptible to excitotoxicity. Accordingly, excessive neuronal cell death was seen in Slack-deficient primary cerebellar granule cell (CGC) cultures exposed to glutamate and NMDA. Differences in neuronal survival between WT and Slack KO CGCs were largely abolished by the NMDAR antagonist MK-801, but not by NBQX, a potent and highly selective competitive antagonist of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type ionotropic glutamate receptors. Interestingly, NMDAR-evoked Ca2+ signals did not differ with regard to Slack genotype in CGCs. However, real-time monitoring of K+ following NMDAR activation revealed a significant contribution of this channel to the intracellular drop in K+ . Finally, TrkB and TrkC neurotrophin receptor transcript levels were elevated in NMDA-exposed Slack-proficient CGCs, suggesting a mechanism by which this K+ channel contributes to the activation of the extracellular-signal-regulated kinase (Erk) pathway and thereby to neuroprotection. Combined, our findings suggest that Slack-dependent K+ signals oppose the NMDAR-mediated excitotoxic neuronal injury by promoting pro-survival signaling via the BDNF/TrkB and Erk axis.

Rituximab-induced mild encephalopathy with a reversible splenial lesion syndrome (MERS): An adverse effect to add to the list.

Mild encephalopathy with a reversible splenial lesion syndrome (MERS) is a rare clinico-radiological entity. Rituximab (RTX)-induced MERS has never been described before. Herein, we report the case of a 33-year-old patient diagnosed since 2017, with an IgG4-related disease (IgG4-RD). This diagnosis was retained in the face of a prolonged fever, sicca syndrome, hepatic damage and renal pseudotumour associated to a high level of IGg4 at 2.8 g/L with suggestive renal histology. The patient was treated with corticosteroid therapy with persistence of renal impairment and nephrotic syndrome indicating RTX therapy. The patient received his first dose of RTX and presented neurological and respiratory impairments a few hours afterwards. An infectious investigation comprising a SARS CoV-2 PCR and viral PCRs (VZV, herpes and CMV) on cerebrospinal fluid (CSF) were negative. The HBV, HCV, HIV, Parvo B19, CMV, EBV, herpes, mycoplasma and syphilis serologies as well as Legionella antigenuria were also negative. The patient had received intravenous immunoglobulins (IVIG) and methylprednisone, associated with sodium valproate with favourable outcome. The diagnosis of MERS induced by RTX was retained in our patient according to clinical and radiological features. We herein report the first case of MERS following RTX in a patient treated for IgG4-RD.

Correlation of magnetic resonance images with neuropathology of irreversible metronidazole-induced encephalopathy: an autopsy case report.

BACKGROUND: Neurological symptoms and radiographic abnormalities may remain in a small proportion of patients with metronidazole-induced encephalopathy (MIE). Although experimental animal models of MIE have suggested a Wernicke's encephalopathy-like pathology, little is known about the histopathological features of MIE. Here we report the first autopsy case of irreversible MIE. CASE PRESENTATION: A 72-year-old Japanese woman with pancreatic neuroendocrine tumour and metastatic tumours in the liver developed intraabdominal bleeding from a hepatic abscess. She was administered metronidazole for 79 days (1.5 g/day), which caused dysarthria followed by hand tremor and altered mental status. Brain magnetic resonance imaging at the time of onset revealed hyperintensities in the deep white matter of the bilateral parietal lobes and splenium of the corpus callosum on diffusion-weighted imaging (DWI) with reduced apparent diffusion coefficient (ADC) values. Despite the improvement of dysarthria and hand tremor, her cognition remained affected even after the withdrawal of metronidazole. She died of pancreatic neuroendocrine tumour at the age of 74 years. Histopathological examinations of the brain confirmed a combination of severe demyelination and moderate axonal degeneration, which corresponded to the regions showing abnormal signal intensities on DWI with reduced ADC values. There were no pathological findings suggestive of Wernicke's encephalopathy in the brain. CONCLUSION: We have demonstrated the clinical, radiographic and histopathological aspects of irreversible MIE. Hyperintensities on DWI with reduced ADC values in affected regions may indicate a poor clinical prognosis due to irreversible pathological damage.