Excitatory amino acids as a final common pathway for neurologic disorders

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same individuals. The comorbidity of the two neurological disorders represents a grave health threat to older populations. This review presents a brief background of the development of novel concepts and their clinical potentials. The activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca 2+ influx is critical for neuronal function. An ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca 2+ mainly via N-methyl-D-aspartate receptors, particularly of those at the extrasynaptic site. This Ca 2+ -evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute excitotoxicity. Furthermore, mild but sustained Ca 2+ increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic, but gradually set off deteriorating Ca 2+ -dependent signals and neuronal cell loss mostly because of activation of programmed cell death pathways. Based on the Ca 2+ hypothesis of Alzheimer's disease and recent advances, this Ca 2+ -activated "silent" degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic neuropathogenesis. The N-methyl-D-aspartate receptor subunit GluN3A, primarily at the extrasynaptic site, serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic excitotoxicity. Ischemic stroke and Alzheimer's disease, therefore, share an N-methyl-D-aspartate receptor- and Ca 2+ -mediated mechanism, although with much different time courses. It is thus proposed that early interventions to control Ca 2+ homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related dementia. This early treatment simultaneously serves as a preconditioning therapy against ischemic stroke that often attacks the same individuals during abnormal aging.

Neuroserpin and Extracellular Vesicles in Ischemic Stroke: Partners in Neuroprotection?

Ischemic stroke represents a significant global health challenge, often resulting in death or long-term disability, particularly among the elderly, where advancing age stands as the most unmodifiable risk factor. Arising from the blockage of a brain-feeding artery, the only therapies available to date aim at removing the blood clot to restore cerebral blood flow and rescue neuronal cells from death. The prevailing treatment approach involves thrombolysis by administration of recombinant tissue plasminogen activator (tPA), albeit with a critical time constraint. Timely intervention is imperative, given that delayed thrombolysis increases tPA leakage into the brain parenchyma, causing harmful effects. Strategies to preserve tPA's vascular benefits while shielding brain cells from its toxicity have been explored. Notably, administering neuroserpin (Ns), a brain-specific tPA inhibitor, represents one such approach. Following ischemic stroke, Ns levels rise and correlate with favorable post-stroke outcomes. Studies in rodent models of focal cerebral ischemia have demonstrated the beneficial effects of Ns administration. Ns treatment maintains blood-brain barrier (BBB) integrity, reducing stroke volume. Conversely, Ns-deficient animals exhibit larger stroke injury, increased BBB permeability and enhanced microglia activation. Furthermore, Ns administration extends the therapeutic window for tPA intervention, underscoring its potential in stroke management. Remarkably, our investigation reveals the presence of Ns within extracellular vesicles (EVs), small membrane-surrounded particles released by all cells and critical for intercellular communication. EVs influence disease outcome following stroke through cargo transfer between cells. Clarifying the role of EVs containing NS could open up urgently needed novel therapeutic approaches to improve post-ischemic stroke outcome.

Riluzole is Effective on Spinal Decompression for Treating Acute Spinal Injury When Compared With Methylprednisolone and the Combination of Two Drugs: In Vivo Rat Model

STUDY DESIGN

Randomized controlled animal experiment.

OBJECTIVES

To determine and compare the efficacy of riluzole, MPS and the combination of two drugs in a rat model with acute spinal trauma, electrophysiologically and histopathologically.

METHODS

59 rats were divided into 4 groups as control, riluzole (6 mg/kg, every 12 hours for 7 days), MPS (30 mg/kg, 2nd and 4th hours after injury) and riluzole + MPS. Spinal trauma was created and the subjects were followed for 7 days. Electrophysiological recordings were made via neuromonitoring. The subjects were sacrificed and histopathological examination was made.

RESULTS

For the amplitude values, mean alteration in the period from the spinal cord injury to the end of the 7th day is 15.89 ± 20.00%, 210.93 ± 199.44%, 24.75% ± 10.13% increase and 18.91 ± 30.01% decrease for the control, riluzole, riluzole + MPS and MPS groups, respectively. Although the riluzole treatment group produced the greatest increase in amplitude, it was observed that no treatment provided a significant improvement compared to the control group, in terms of latency and amplitude. It was observed that there was significantly less cavitation area in the riluzole treatment group compared to the control group (P = .020). (P < .05).

CONCLUSIONS

Electrophysiologically, no treatment was found to provide significant improvement. Histopathologically, it was observed that riluzole provided significant neural tissue protection.

miR-540-3p partially recovers the locomotor function of spinal cord injury mice by targeting SIX4/Yap1 and inactivation of astrocytes

BACKGROUND

Spinal cord injury (SCI) lacks therapeutic reagents. miRNAs are responsible for mesenchymal stem cells (MSCs) therapy in spinal cord injury.

PURPOSE

To discover the underlying therapeutic miRNA target and its mechanism for the treatment of SCI.

METHOD

Two RNA sequence datasets were retrieved from the GEO Datasets database which was accessed on 30 December 2023. The targets of the top 2 ranked miRNAs (miR-540-3p and miR-433-5p) were analyzed using online databases (miRDB, miRMap, TargetScan and STRING database) and both miRNAs were screened by cell counting kit-8 (CCK-8) assay. Then, transfection and local injection of miR-540-3p were performed to examine the capacity of secretion of astrocytes and the locomotor function of SCI mice.

RESULTS

The significantly high levels of miR-540-3p/433-5p were revealed. Transfection of miR-540-3p conferred inactivation of reactive astrocytes and weakened the capacity of secreting inflammatory cytokines of astrocytes. miR-433-5p was proven to not impact the proliferation of astrocytes. Co-culture of culture supernate from astrocytes transfected with miR-540-3p and neurons demonstrated the significantly preserved neurite length and decreased apoptotic level of neurons. Meanwhile, sine oculis homeobox (SIX4)/Yap1, as the target of miR-540-3p, is critical for abrogating inflammatory damage of neurons in vivo and in vitro, decreasing glial scar, and recovering locomotor function of spinal cord injury mice. Furthermore, SCI mice receiving a local injection of miR-540-3p showed smaller and lighter bladder volume and higher limb strength, but the period from urinary retention to autonomous urination of SCI mice showed no significance.

CONCLUSIONS

Conclusively, miR-540 discovered from hypoxia-treated exosomes suppresses the inflammatory cytokines secreted by reactive astrocytes, partially preserves the neuronal function of spinal cord injury mice, through the SIX4/Yap1 signalling pathway.

Inhibition of the NMDA Currents by Probenecid in Amygdaloid Kindling Epilepsy Model

Epilepsy is characterized by a sustained depolarization and repeated discharge of neurons, attributed to overstimulation of N-methyl-D-aspartate receptors (NMDAr). Herein, we propose that probenecid (PROB), an inhibitor of the activity of some ATP binding-cassette transporters (ABC-transporters) can modify NMDAr activity and expression in amygdaloid kindled model. Some studies have suggested that NMDAr expression could be regulated by inhibiting the activity of P-glycoprotein (MDR1) and drug resistance protein-1 (MRP1). Besides, PROB was found to interact with other proteins with proven activity in the kindling model, such as TRPV2 channels, OAT1, and Panx1. Administering PROB at two doses (100 and 300 mg/kg/d) for 5 d decreased after-discharge duration and Racine behavioral scores. It also reduced the expression of NR2B and the activity of total NOS and the expression of nNOS with respect to the kindling group. In a second protocol, voltage-clamp measurements of NMDA-evoked currents were performed in CA1 hippocampal cells dissociated from control and kindled rats. PROB produced a dose-dependent reduction in NMDA-evoked currents. In neurons from kindled rats, a residual NMDA-evoked current was registered with respect to control animals, while a reduction in NMDA-evoked currents was observed in the presence of 20 mM PROB. Finally, we evaluated the expression of MRP1 and MDR1 in order to establish a relationship between the reduction of kindling parameters, the inhibition of NMDA-type currents, and the expression of these transporters. Based on our results, we conclude that at the concentrations used, PROB inhibits currents evoked by NMDA in dissociated neurons of control and kindled rats. In the kindling model, at the tested doses, PROB decreases the after-discharge duration and Racine behavioral score in the kindling model. We propose a mechanism that could be dependent on the expression of ABC-type transporters.

Intramyelinic edema manifesting as central white matter diffusion restriction associated with brain contusion in pediatric patients

In traumatic brain injury, white matter diffusion restriction can be an imaging manifestation of non-hemorrhagic axonal injury. In this article, a different pattern of widespread white matter diffusion restriction associated with ipsilateral cortical damage, all noted in pediatric and young adult TBI patients, is presented. Its atypical pattern of distribution and extensive scope on imaging suggest excitotoxicity and intramyelinic edema as possible underlying mechanisms.

Pentylenetetrazole-Induced Seizures in Wistar Male Albino Rats with Reference to Glutamate Metabolism

Background and Purpose

Epilepsy is a common and heterogenous neurological disorder characterized by recurrent spontaneous seizures. Animal models like rats play a crucial role in finding of mechanism of epilepsy in different brain regions. i.e., cerebral cortex, cerebellum, hippocampus, and pons medulla. Glutamate is an important excitatory neurotransmitter in the central nervous system and also glutamate plays a vital role in neuronal development and memory. The process of neuronal death evolved by glutamate receptor activation, has been hypothesized in both acute and chronic degenerative disorders including epilepsy. Considering the multifactorial neurochemical and neurophysiological malfunctions consequent to epileptic seizures, a few antiepileptic drugs are designed, to mitigate the debilitating aspects of epilepsy.

Methods

Rat model, pentylenetetrazole (PTZ), an anticonvulsant drug, was selected for the present study. Induction of epilepsy/convulsions was induced by an intraperitoneal injection of PTZ (60 mg/kg body weight) in saline. Biochemical assays performed through spectrophotometer.

Results

Glutamine and Glutamine synthetase levels were decreased in the epileptic rats brain regions i.e., hippocampus, cerebellum, cerebral cortex, and pons medulla; glutamate dehydrogenase and glutaminase levels were increased in all the regions of epilepsy induced rats. Highest values are recorded in hippocampus when compared to other brain regions.

Conclusion

PTZ suppresses the function of Glutamine and Glutamine synthetase activities in selected brain regions of rat and enhances the activities of the glutaminase and glutamate dehydrogenase when compared to control rats.

Network analysis of S-nitrosylated synaptic proteins demonstrates unique roles in health and disease

Nitric oxide can covalently modify cysteine thiols on target proteins to alter that protein's function in a process called S-nitrosylation (SNO). S-nitrosylation of synaptic proteins plays an integral part in neurotransmission. Here we review the function of the SNO-proteome at the synapse and whether clusters of SNO-modification may predict synaptic dysfunction associated with disease. We used a systematic search strategy to concatenate SNO-proteomic datasets from normal human or murine brain samples. Identified SNO-modified proteins were then filtered against proteins reported in the Synaptome Database, which provides a detailed and experimentally verified annotation of all known synaptic proteins. Subsequently, we performed an unbiased network analysis of all known SNO-synaptic proteins to identify clusters of SNO proteins commonly involved in biological processes or with known disease associations. The resulting SNO networks were significantly enriched in biological processes related to metabolism, whereas significant gene-disease associations were related to Schizophrenia, Alzheimer's, Parkinson's and Huntington's disease. Guided by an unbiased network analysis, the current review presents a thorough discussion of how clustered changes to the SNO-proteome influence health and disease.

Toxic and Drug-Related White Matter Diseases of the Brain and Spine

Toxic leukoencephalopathy and myelopathy are common neurologic complications of a wide range of chemotherapeutic and substance abuse agents. During the last decade, there has been a significant change in the profile of white matter toxins, primarily driven by the development and usage of new chemotherapeutic and immunotherapeutic agents and by the continuous increase in illicit drug abuse with contaminants. Neuroimaging in the form of MR imaging forms the cornerstone in the diagnosis of these entities, many of which are reversible and amenable to rapid correction. Chronic white matter changes are also seen with these toxins with gradually progressive clinicoradiological findings.

Increased glucose metabolism and impaired glutamate transport in human astrocytes are potential early triggers of abnormal extracellular glutamate accumulation in hiPSC-derived models of Alzheimer's disease

Glutamate recycling between neurons and astrocytes is essential to maintain neurotransmitter homeostasis. Disturbances in glutamate homeostasis, resulting in excitotoxicity and neuronal death, have been described as a potential mechanism in Alzheimer's disease (AD) pathophysiology. However, glutamate neurotransmitter metabolism in different human brain cells, particularly astrocytes, has been poorly investigated at the early stages of AD. We sought to investigate glucose and glutamate metabolism in AD by employing human induced pluripotent stem cell (hiPSC)-derived astrocytes and neurons carrying mutations in the amyloid precursor protein (APP) or presenilin-1 (PSEN-1) gene as found in familial types of AD (fAD). Methods such as live-cell bioenergetics and metabolic mapping using [13C]-enriched substrates were used to examine metabolism in the early stages of AD. Our results revealed greater glycolysis and glucose oxidative metabolism in astrocytes and neurons with APP or PSEN-1 mutations, accompanied by an elevated glutamate synthesis compared to control WT cells. Astrocytes with APP or PSEN-1 mutations exhibited reduced expression of the excitatory amino acid transporter 2 (EAAT2), and glutamine uptake increased in mutated neurons, with enhanced glutamate release specifically in neurons with a PSEN-1 mutation. These results demonstrate a hypermetabolic phenotype in astrocytes with fAD mutations possibly linked to toxic glutamate accumulation. Our findings further identify metabolic imbalances that may occur in the early phases of AD pathophysiology.

Mobilizing endogenous neuroprotection: the mechanism of the protective effect of acupuncture on the brain after stroke

Given its high morbidity, disability, and mortality rates, ischemic stroke (IS) is a severe disease posing a substantial public health threat. Although early thrombolytic therapy is effective in IS treatment, the limited time frame for its administration presents a formidable challenge. Upon occurrence, IS triggers an ischemic cascade response, inducing the brain to generate endogenous protective mechanisms against excitotoxicity and inflammation, among other pathological processes. Stroke patients often experience limited recovery stages. As a result, activating their innate self-protective capacity [endogenous brain protection (EBP)] is essential for neurological function recovery. Acupuncture has exhibited clinical efficacy in cerebral ischemic stroke (CIS) treatment by promoting the human body's self-preservation and "Zheng Qi" (a term in traditional Chinese medicine (TCM) describing positive capabilities such as self-immunity, self-recovery, and disease prevention). According to research, acupuncture can modulate astrocyte activity, decrease oxidative stress (OS), and protect neurons by inhibiting excitotoxicity, inflammation, and apoptosis via activating endogenous protective mechanisms within the brain. Furthermore, acupuncture was found to modulate microglia transformation, thereby reducing inflammation and autoimmune responses, as well as promoting blood flow restoration by regulating the vasculature or the blood-brain barrier (BBB). However, the precise mechanism underlying these processes remains unclear. Consequently, this review aims to shed light on the potential acupuncture-induced endogenous neuroprotective mechanisms by critically examining experimental evidence on the preventive and therapeutic effects exerted by acupuncture on CIS. This review offers a theoretical foundation for acupuncture-based stroke treatment.

Memantine Improves Memory and Neurochemical Damage in a Model of Maple Syrup Urine Disease

Maple Syrup Urine Disease (MSUD) is a metabolic disease characterized by the accumulation of branched-chain amino acids (BCAA) in different tissues due to a deficit in the branched-chain alpha-ketoacid dehydrogenase complex. The most common symptoms are poor feeding, psychomotor delay, and neurological damage. However, dietary therapy is not effective. Studies have demonstrated that memantine improves neurological damage in neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. Therefore, we hypothesize that memantine, an NMDA receptor antagonist can ameliorate the effects elicited by BCAA in an MSUD animal model. For this, we organized the rats into four groups: control group (1), MSUD group (2), memantine group (3), and MSUD + memantine group (4). Animals were exposed to the MSUD model by the administration of BCAA (15.8 µL/g) (groups 2 and 4) or saline solution (0.9%) (groups 1 and 3) and treated with water or memantine (5 mg/kg) (groups 3 and 4). Our results showed that BCAA administration induced memory alterations, and changes in the levels of acetylcholine in the cerebral cortex. Furthermore, induction of oxidative damage and alterations in antioxidant enzyme activities along with an increase in pro-inflammatory cytokines were verified in the cerebral cortex. Thus, memantine treatment prevented the alterations in memory, acetylcholinesterase activity, 2',7'-Dichlorofluorescein oxidation, thiobarbituric acid reactive substances levels, sulfhydryl content, and inflammation. These findings suggest that memantine can improve the pathomechanisms observed in the MSUD model, and may improve oxidative stress, inflammation, and behavior alterations.

TwinF interface inhibitor FP802 stops loss of motor neurons and mitigates disease progression in a mouse model of ALS

Toxic signaling by extrasynaptic NMDA receptors (eNMDARs) is considered an important promoter of amyotrophic lateral sclerosis (ALS) disease progression. To exploit this therapeutically, we take advantage of TwinF interface (TI) inhibition, a pharmacological principle that, contrary to classical NMDAR pharmacology, allows selective elimination of eNMDAR-mediated toxicity via disruption of the NMDAR/TRPM4 death signaling complex while sparing the vital physiological functions of synaptic NMDARs. Post-disease onset treatment of the SOD1G93A ALS mouse model with FP802, a modified TI inhibitor with a safe pharmacology profile, stops the progressive loss of motor neurons in the spinal cord, resulting in a reduction in the serum biomarker neurofilament light chain, improved motor performance, and an extension of life expectancy. FP802 also effectively blocks NMDA-induced death of neurons in ALS patient-derived forebrain organoids. These results establish eNMDAR toxicity as a key player in ALS pathogenesis. TI inhibitors may provide an effective treatment option for ALS patients.

Pathological phenotypes of astrocytes in Alzheimer's disease

Astrocytes are involved in various processes in the central nervous system (CNS). As the most abundant cell type in the CNS, astrocytes play an essential role in neuronal maintenance and support, synaptic activity, neuronal metabolism, and amyloid-beta (Aβ) clearance. Alzheimer's disease (AD) is a neurodegenerative disorder associated with cognitive and behavioral impairment. The transformation of astrocytes is involved in various neurodegenerative diseases, such as AD. Since astrocytes have functional diversity and morphological and physiological heterogeneity in the CNS, AD-related astrocytes might show various pathological phenotypes during AD. Astrocytes developing pathological phenotypes could contribute to AD progression. In this review, we provide an overview of the pathological phenotypes of astrocytes in the context of AD, highlighting recent findings in human and mouse AD.

Ursolic acid inhibits the synaptic release of glutamate and prevents glutamate excitotoxicity in rats

The present study evaluated the effect of ursolic acid, a natural pentacyclic triterpenoid, on glutamate release in rat cortical nerve terminals (synaptosomes) and its neuroprotection in a kainic acid-induced excitotoxicity rat model. In cortical synaptosomes, ursolic acid produced a concentration-dependent inhibition of evoked glutamate release with a half-maximum inhibition of release value of 9.5 μM, and calcium-free medium and the P/Q -type Ca2+ channel blocker, ω-agatoxin IVA, but not ω-conotoxin GVIA, an N-type Ca2+ channel blocker, prevented the ursoloic acid effect. The molecular docking study indicated that ursolic acid interacted with P/Q-type Ca2+ channels. Ursolic acid also significantly decreased the depolarization-induced activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and the subsequent phosphorylation of synapsin I, and the ursolic acid effect on evoked glutamate release was inhibited by the CaMKII inhibitor KN 62 in synaptosomes. In addition, in rats that were intraperitoneally injected with ursolic acid 30 min before kainic acid intraperitoneal injection, cortical neuronal degeneration was attenuated. This effect of ursolic acid in the improvement of kainic acid-induced neuronal damage was associated with the reduction of kainic acid-induced glutamate increase in the cortex of rats; this was characterized by the reduction of glutamate and glutaminase levels and elevation of glutamate dehydrogenase, glutamate transporter 1, glutamate-aspartate transporter, and glutamine synthetase protein levels. These results suggest that ursolic acid inhibits glutamate release from cortical synaptosomes by decreasing P/Q-type Ca2+ channel activity and subsequently suppressing CaMKII and exerts a preventive effect against glutamate neurotoxicity by controlling glutamate levels.

Design and Characterization of Prodrug-like Inhibitors for Preventing Glutamate Efflux through Reverse Transport

Glutamate transporters are responsible for active transport of the major excitatory neurotransmitter glutamate across the cell membrane, regulating the extracellular glutamate concentration in the mammalian brain. Extracellular glutamate levels in the brain are usually in the submicromolar range but can increase by exocytosis, inhibition of cellular uptake, or through glutamate release by reverse transport, as well as other mechanisms, which can lead to neurodegeneration and neuronal cell death. Such conditions can be encountered upon energy deprivation during an ischemic stroke. Here, we developed acetoxymethyl (AM) ester prodrug-like derivatives of excitatory amino acid transporter (EAAT) inhibitors that permeate the cell membrane and are activated, most likely through hydrolysis by endogenous cellular esterases, to form the active EAAT inhibitor. Upon increase in external K+ concentration, the inhibitors block glutamate efflux by EAAT reverse transport. Using a novel high-affinity fluorescent prodrug-like inhibitor, dl-threo-9-anthracene-methoxy-aspartate (TAOA) AM ester, we demonstrate that the precursor rapidly accumulates inside cells. Electrophysiological methods and fluorescence assays utilizing the iGluSnFR external glutamate sensor were used to demonstrate the efficacy of AM ester-protected inhibitors in inhibiting K+-mediated glutamate release. Together, our results provide evidence for a novel method to potentially prevent glutamate release by reverse transport under pathophysiological conditions in a model cell system, as well as in human astrocytes, while leaving glutamate uptake under physiological conditions operational. This method could have wide-ranging applications in the prevention of glutamate-induced neuronal cell death.

Mitragynine inhibits hippocampus neuroplasticity and its molecular mechanism

BACKGROUND

Mitragynine (MIT), the primary indole alkaloid of kratom (Mitragyna speciosa), has been associated with addictive and cognitive decline potentials. In acute studies, MIT decreases spatial memory and inhibits hippocampal synaptic transmission in long-term potentiation (LTP). This study investigated the impacts of 14-day MIT treatment on hippocampus synaptic transmission and its possible underlying mechanisms.

METHODS

Under urethane anesthesia, field excitatory post-synaptic potentials (fEPSP) of the hippocampal CA1 region were recorded in the Sprague Dawley (SD) rats that received MIT (1, 5, and 10 mg/kg), morphine (MOR) 5 mg/kg, or vehicle (ip). The effects of the treatments on basal synaptic transmission, paired-pulse facilitation (PPF), and LTP were assessed in the CA1 region. Analysis of the brain's protein expression linked to neuroplasticity was then performed using a western blot.

RESULTS

The baseline synaptic transmission's amplitude was drastically decreased by MIT at 5 and 10 mg/kg doses, although the PPF ratio before TBS remained unchanged, the PPF ratio after TBS was significantly reduced by MIT (10 mg/kg). Strong and persistent inhibition of LTP was generated in the CA1 region by MIT (5 and 10 mg/kg) doses; this effect was not seen in MIT (1 mg/kg) treated rats. In contrast to MIT (1 mg/kg), MIT (5 and 10 mg/kg) significantly raised the extracellular glutamate levels. After exposure to MIT, GluR-1 receptor expression remained unaltered. However, NMDAε2 receptor expression was markedly downregulated. The expression of pCaMKII, pERK, pCREB, BDNF, synaptophysin, PSD-95, Delta fosB, and CDK-5 was significantly downregulated in response to MIT (5 and 10 mg/kg) exposure, while MOR (5 mg/kg) significantly raised synaptophysin and Delta fosB expression.

CONCLUSION

Findings from this work reveal that a smaller dose of MIT (1 mg/kg) poses no risk to hippocampal synaptic transmission. Alteration in neuroplasticity-associated proteins may be a molecular mechanism for MIT (5 and 10 mg/kg)-induced LTP disruption and cognitive impairments. Data from this work posit that MIT acted differently from MOR on neuroplasticity and its underlying mechanisms.

Protection of the Vascular System by Polyethylene Glycol Reduces Secondary Injury Following Spinal Cord Injury in Rats

BACKGROUND

Polyethylene glycol (PEG) is a hydrophilic polymer, which has been known to have a neuroprotective effect by sealing the ruptured cell membrane, but PEG effects on the vascular systems and its underlying mechanisms remain unclear. Here, we showed the neuroprotective effect of PEG by preventing damage to the vascular system.

METHODS

A spinal contusion was made at the T11 segment in male Sprague-Dawley rats. PEG was injected into the subdural space immediately after SCI. Vascular permeability was assessed for 24 h after SCI using intraperitoneally injected Evans blue dye. Junctional complexes were stained with CD31 and ZO-1. Infarct size was analyzed using triphenyltetrazolium chloride, and blood vessels were counted in the epicenter. Behavioral tests for motor and sensory function were performed for 6 weeks. And then the tissue-sparing area was assessed.

RESULTS

Immediately applied PEG significantly reduced the vascular permeability at 6, 12, and 24 h after SCI when it compared to saline, and infarct size was also reduced at 0, 6, and 24 h after SCI. In addition, a great number of blood vessels were observed in PEG group at 6 and 24 h after SCI compared to those of the saline group. The PEG group also showed a significant improvement in motor function. And tissue-sparing areas in the PEG were greater than those of the saline group.

CONCLUSION

The present results provide preclinical evidence for the neuroprotective effects of PEG as a promising therapeutic agent for reducing secondary injury following SCI through vascular protection.

Assessing the occurrence and severity of pre- and postendodontic pain in anemic and healthy female patients

OBJECTIVES

The objective of this current survey was to assess both the occurrence and severity of pre- and post-endodontic pain among female individuals, distinguishing between those with anemia and those without.

MATERIALS AND METHODS

In the current study, we included a total of 60 women with anemia (hemoglobin < 11) and those without anemia (hemoglobin > 13). We recorded the occurrence and severity of pain before and at 24, 48, and 72 h following root canal treatment using a visual analog scale (VAS) ranging from 0 to 10. Additionally, we collected data on patient age, tooth type, as well as pulpal and periapical conditions. Statistical analysis was carried out using two-way ANOVA, pairedt-tests, and Pearson correlation coefficient. The significance level for statistical tests was set at p ≤ .05.

RESULTS

The incidence of preoperative pain in both anemic and non-anemic patients was 80%. The total incidence of post-operative pain was recorded as 71.7% (82.2% in anemic and 61.1% in non-anemic women). Compared with the pretreatment pain incidence and intensity, the values increased in 24 h but declined in 48 h and 72 h after treatment. Considering the posttreatment pain intensity, the mean values were higher in the three time intervals (24, 48, and 72 h) in anemic patients. Pulpal and periapical status, in contrast to age and tooth type, significantly contributed to the intensity of posttreatment pain.

CONCLUSION

Regarding the importance of pain phenomenon in human life, it is recommended to consider anemia as an important risk factor for post-endodontic pain. Early diagnosis and analgesic treatment interventions in anemic females, alongside the pain control during root canal treatment, could promote the patient's satisfaction and quality of care.

Sex Differences in the Preventive Effect of Cardiovascular and Metabolic Therapeutics on Dementia

Dementia is a clinical syndrome characterized by progressive impairment of cognitive and functional abilities. As currently applied treatments for dementia can only delay the progression of dementia and cannot fundamentally cure it, much attention is being paid to reducing its incidence by preventing the associated risk factors. Cardiovascular and metabolic diseases are well-known risk factors for dementia, and many studies have attempted to prevent dementia by treating these risk factors. Growing evidence suggests that sex-based factors may play an important role in the pathogenesis of dementia. Therefore, a deeper understanding of the differences in the effects of drugs based on sex may help improve their effectiveness. In this study, we reviewed sex differences in the impact of therapeutics targeting risk factors for dementia, such as cardiovascular and metabolic diseases, to prevent the incidence and/or progression of dementia.

Moschus ameliorates glutamate-induced cellular damage by regulating autophagy and apoptosis pathway

Alzheimer's disease (AD), a neurodegenerative disorder, causes short-term memory and cognition declines. It is estimated that one in three elderly people die from AD or other dementias. Chinese herbal medicine as a potential drug for treating AD has gained growing interest from many researchers. Moschus, a rare and valuable traditional Chinese animal medicine, was originally documented in Shennong Ben Cao Jing and recognized for its properties of reviving consciousness/resuscitation. Additionally, Moschus has the efficacy of "regulation of menstruation with blood activation, relief of swelling and pain" and is used for treating unconsciousness, stroke, coma, and cerebrovascular diseases. However, it is uncertain whether Moschus has any protective effect on AD patients. We explored whether Moschus could protect glutamate (Glu)-induced PC12 cells from cellular injury and preliminarily explored their related action mechanisms. The chemical compounds of Moschus were analyzed and identified by GC-MS. The Glu-induced differentiated PC12 cell model was thought to be the common AD cellular model. The study aims to preliminarily investigate the intervention effect of Moschus on Glu-induced PC12 cell damage as well as their related action mechanisms. Cell viability, lactate dehydrogenase (LDH), mitochondrial reactive oxygen species, mitochondrial membrane potential (MMP), cell apoptosis, autophagic vacuoles, autolysosomes or autophagosomes, proteins related to apoptosis, and the proteins related to autophagy were examined and analyzed. Seventeen active compounds of the Moschus sample were identified based on GC-MS analysis. In comparison to the control group, Glu stimulation increased cell viability loss, LDH release, mitochondrial damage, loss of MMP, apoptosis rate, and the number of cells containing autophagic vacuoles, and autolysosomes or autophagosomes, while these results were decreased after the pretreatment with Moschus and 3-methyladenine (3-MA). Furthermore, Glu stimulation significantly increased cleaved caspase-3, Beclin1, and LC3II protein expression, and reduced B-cell lymphoma 2/BAX ratio and p62 protein expression, but these results were reversed after pretreatment of Moschus and 3-MA. Moschus has protective activity in Glu-induced PC12 cell injury, and the potential mechanism might involve the regulation of autophagy and apoptosis. Our study may promote research on Moschus in the field of neurodegenerative diseases, and Moschus may be considered as a potential therapeutic agent for AD.

Diabetes Reshapes the Circadian Transcriptome Profile in Murine Retina

Purpose

Diabetic retinopathy (DR) is a common complication of diabetes and has a high prevalence. Dysregulation of circadian rhythmicity is associated with the development of DR. This research aimed to investigate rhythmical transcriptome alterations in the retina of diabetic mice.

Methods

C57BL/6J mice were used to establish a diabetes model by intraperitoneal injection of streptozotocin (STZ). After 12 weeks, retinas were collected continuously at 4-hour intervals over 1 day. Total RNA was extracted from normal and STZ-treated retinas and RNA sequencing was performed. Meta2d algorithm, Kyoto Encyclopedia of Genes, Phase Set Enrichment Analysis, and time-series cluster analysis were used to identify, analyze and annotate the composition, phase, and molecular functions of rhythmic transcripts in retinas.

Results

The retina exhibited powerful transcriptome rhythmicity. STZ-induced diabetes markedly modified the transcriptome characteristics of the circadian transcriptome in the retina, including composition, phase, and amplitude. Moreover, the diabetic mice led to re-organized temporal and clustering enrichment pathways in space and time and affected core clock machinery.

Conclusions

Diabetes impairs the circadian rhythm of the transcriptomic profile of retinas. This study offers new perspectives on the negative effects of diabetes on the retina, which may provide important information for the development of new treatments for DR.

Gut Microbial Metabolome and Dysbiosis in Neurodegenerative Diseases: Psychobiotics and Fecal Microbiota Transplantation as a Therapeutic Approach-A Comprehensive Narrative Review

The comprehensive narrative review conducted in this study delves into the mechanisms of communication and action at the molecular level in the human organism. The review addresses the complex mechanism involved in the microbiota-gut-brain axis as well as the implications of alterations in the microbial composition of patients with neurodegenerative diseases. The pathophysiology of neurodegenerative diseases with neuronal loss or death is analyzed, as well as the mechanisms of action of the main metabolites involved in the bidirectional communication through the microbiota-gut-brain axis. In addition, interventions targeting gut microbiota restructuring through fecal microbiota transplantation and the use of psychobiotics-pre- and pro-biotics-are evaluated as an opportunity to reduce the symptomatology associated with neurodegeneration in these pathologies. This review provides valuable information and facilitates a better understanding of the neurobiological mechanisms to be addressed in the treatment of neurodegenerative diseases.

Inhibiting NLRP3 inflammasome signaling pathway promotes neurological recovery following hypoxic-ischemic brain damage by increasing p97-mediated surface GluA1-containing AMPA receptors

BACKGROUND

The nucleotide-binding oligomeric domain (NOD)-like receptor protein 3 (NLRP3) inflammasome is believed to be a key mediator of neuroinflammation and subsequent secondary brain injury induced by ischemic stroke. However, the role and underlying mechanism of the NLRP3 inflammasome in neonates with hypoxic-ischemic encephalopathy (HIE) are still unclear.

METHODS

The protein expressions of the NLRP3 inflammasome including NLRP3, cysteinyl aspartate specific proteinase-1 (caspase-1) and interleukin-1β (IL-1β), the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionicacid receptor (AMPAR) subunit, and the ATPase valosin-containing protein (VCP/p97), were determined by Western blotting. The interaction between p97 and AMPA glutamate receptor 1 (GluA1) was determined by co-immunoprecipitation. The histopathological level of hypoxic-ischemic brain damage (HIBD) was determined by triphenyltetrazolium chloride (TTC) staining. Polymerase chain reaction (PCR) and Western blotting were used to confirm the genotype of the knockout mice. Motor functions, including myodynamia and coordination, were evaluated by using grasping and rotarod tests. Hippocampus-dependent spatial cognitive function was measured by using the Morris-water maze (MWM).

RESULTS

We reported that the NLRP3 inflammasome signaling pathway, such as NLRP3, caspase-1 and IL-1β, was activated in rats with HIBD and oxygen-glucose deprivation (OGD)-treated cultured primary neurons. Further studies showed that the protein level of the AMPAR GluA1 subunit on the hippocampal postsynaptic membrane was significantly decreased in rats with HIBD, and it could be restored to control levels after treatment with the specific caspase-1 inhibitor AC-YVAD-CMK. Similarly, in vitro studies showed that OGD reduced GluA1 protein levels on the plasma membrane in cultured primary neurons, whereas AC-YVAD-CMK treatment restored this reduction. Importantly, we showed that OGD treatment obviously enhanced the interaction between p97 and GluA1, while AC-YVAD-CMK treatment promoted the dissociation of p97 from the GluA1 complex and consequently facilitated the localization of GluA1 on the plasma membrane of cultured primary neurons. Finally, we reported that the deficits in motor function, learning and memory in animals with HIBD, were ameliorated by pharmacological intervention or genetic ablation of caspase-1.

CONCLUSION

Inhibiting the NLRP3 inflammasome signaling pathway promotes neurological recovery in animals with HIBD by increasing p97-mediated surface GluA1 expression, thereby providing new insight into HIE therapy.

Extrasynaptic NMDA receptors in acute and chronic excitotoxicity: implications for preventive treatments of ischemic stroke and late-onset Alzheimer's disease

Stroke and late-onset Alzheimer's disease (AD) are risk factors for each other; the comorbidity of these brain disorders in aging individuals represents a significant challenge in basic research and clinical practice. The similarities and differences between stroke and AD in terms of pathogenesis and pathophysiology, however, have rarely been comparably reviewed. Here, we discuss the research background and recent progresses that are important and informative for the comorbidity of stroke and late-onset AD and related dementia (ADRD). Glutamatergic NMDA receptor (NMDAR) activity and NMDAR-mediated Ca²⁺ influx are essential for neuronal function and cell survival. An ischemic insult, however, can cause rapid increases in glutamate concentration and excessive activation of NMDARs, leading to swift Ca²⁺ overload in neuronal cells and acute excitotoxicity within hours and days. On the other hand, mild upregulation of NMDAR activity, commonly seen in AD animal models and patients, is not immediately cytotoxic. Sustained NMDAR hyperactivity and Ca²⁺ dysregulation lasting from months to years, nevertheless, can be pathogenic for slowly evolving events, i.e. degenerative excitotoxicity, in the development of AD/ADRD. Specifically, Ca²⁺ influx mediated by extrasynaptic NMDARs (eNMDARs) and a downstream pathway mediated by transient receptor potential cation channel subfamily M member (TRPM) are primarily responsible for excitotoxicity. On the other hand, the NMDAR subunit GluN3A plays a "gatekeeper" role in NMDAR activity and a neuroprotective role against both acute and chronic excitotoxicity. Thus, ischemic stroke and AD share an NMDAR- and Ca²⁺-mediated pathogenic mechanism that provides a common receptor target for preventive and possibly disease-modifying therapies. Memantine (MEM) preferentially blocks eNMDARs and was approved by the Federal Drug Administration (FDA) for symptomatic treatment of moderate-to-severe AD with variable efficacy. According to the pathogenic role of eNMDARs, it is conceivable that MEM and other eNMDAR antagonists should be administered much earlier, preferably during the presymptomatic phases of AD/ADRD. This anti-AD treatment could simultaneously serve as a preconditioning strategy against stroke that attacks ≥ 50% of AD patients. Future research on the regulation of NMDARs, enduring control of eNMDARs, Ca²⁺ homeostasis, and downstream events will provide a promising opportunity to understand and treat the comorbidity of AD/ADRD and stroke.

Targeting NMDA receptor in Alzheimer's disease: identifying novel inhibitors using computational approaches

The glutamate-gated ion channels known as N-methyl-d-aspartate receptors (NMDARs) are important for both normal and pathological brain function. Subunit-selective antagonists have high therapeutic promise since many pathological conditions involve NMDAR over activation, although few clinical successes have been reported. Allosteric inhibitors of GluN2B-containing receptors are among the most potential NMDAR targeting drugs. Since the discovery of ifenprodil, a variety of GluN2B-selective compounds have been discovered, each with remarkably unique structural motifs. These results expand the allosteric and pharmacolog-ical spectrum of NMDARs and provide a new structural basis for the development of next-generation GluN2B antagonists that have therapeutic potential in brain diseases. Small molecule therapeutic inhibitors targeting NMDA have recently been developed to target CNS disorders such as Alzheimer's disease. In the current study, a cheminformatics method was used to discover potential antagonists and to identify the structural requirements for Gly/NMDA antagonism. In this case we have created a useful pharmacophore model with solid statistical values. Through pharmacophore mapping, the verified model was used to filter out virtual matches from the ZINC database. Assessing receptor-ligand binding mechanisms and affinities used molecular docking. To find the best hits, the GlideScore and the interaction of molecules with important amino acids were considered essential features. We found some molecular inhibitors, namely, ZINC13729211, ZINC07430424, ZINC08614951, ZINC60927204, ZINC12447511, and ZINC18889258 with high binding affinity using computational methods. The molecules in our studies showed characteristics such as good stability, hydrogen bonding and higher binding affinities in the solvation-based assessment method than ifenprodil with acceptable ADMET profile. Moreover, these six leads have been proposed as potential new perspectives for exploring potent Gly/NMDA receptor antagonists. In addition, it can be tested in the laboratory for potential therapeutic strategies for both in vitro and in vivo research.

Cortical Spreading Depolarization and Delayed Cerebral Ischemia; Rethinking Secondary Neurological Injury in Subarachnoid Hemorrhage

Poor outcomes in Subarachnoid Hemorrhage (SAH) are in part due to a unique form of secondary neurological injury known as Delayed Cerebral Ischemia (DCI). DCI is characterized by new neurological insults that continue to occur beyond 72 h after the onset of the hemorrhage. Historically, it was thought to be a consequence of hypoperfusion in the setting of vasospasm. However, DCI was found to occur even in the absence of radiographic evidence of vasospasm. More recent evidence indicates that catastrophic ionic disruptions known as Cortical Spreading Depolarizations (CSD) may be the culprits of DCI. CSDs occur in otherwise healthy brain tissue even without demonstrable vasospasm. Furthermore, CSDs often trigger a complex interplay of neuroinflammation, microthrombi formation, and vasoconstriction. CSDs may therefore represent measurable and modifiable prognostic factors in the prevention and treatment of DCI. Although Ketamine and Nimodipine have shown promise in the treatment and prevention of CSDs in SAH, further research is needed to determine the therapeutic potential of these as well as other agents.

Systemic Metabolism and Mitochondria in the Mechanism of Alzheimer's Disease: Finding Potential Therapeutic Targets

Elderly people over the age of 65 are those most likely to experience Alzheimer's disease (AD), and aging and AD are associated with apparent metabolic alterations. Currently, there is no curative medication against AD and only several drugs have been approved by the FDA, but these drugs can only improve the symptoms of AD. Many preclinical and clinical trials have explored the impact of adjusting the whole-body and intracellular metabolism on the pathogenesis of AD. The most recent evidence suggests that mitochondria initiate an integrated stress response to environmental stress, which is beneficial for healthy aging and neuroprotection. There is also an increasing awareness of the differential risk and potential targeting strategies related to the metabolic level and microbiome. As the main participants in intracellular metabolism, mitochondrial bioenergetics, mitochondrial quality-control mechanisms, and mitochondria-linked inflammatory responses have been regarded as potential therapeutic targets for AD. This review summarizes and highlights these advances.

Investigation of the effect of sugammadex on glutamate-induced neurotoxicity in C6 cell line and the roles played by nitric oxide and oxidative stress pathways

This experiment was intended to evaluate the effect of sugammadex on the cytotoxicity induced by glutamate, involving the nitric oxide and oxidative stress pathways. C6 glioma cells were used in the study. Glutamate was given to cells in the glutamate group for 24 h. Sugammadex at different concentrations was given to cells in the sugammadex group for 24 h. Cells in the sugammadex + glutamate group were pre-treated with sugammadex at various concentrations for 1 h and then exposed to glutamate for 24 h. XTT assay was used to assess cell viability. Levels of nitric oxide (NO), neuronal nitric oxide synthase (nNOS), total antioxidant (TAS), and total oxidant (TOS) in the cells were calculated using commercial kits. Apoptosis was detected by TUNEL assay. Sugammadex at concentrations of 50 and 100 μg/mL significantly enhanced the cell viability in C6 cells after the cytotoxicity induced by glutamate (p < 0.001). Moreover, sugammadex considerably decreased the levels of nNOS NO and TOS and the number of apoptotic cells and increased the level of TAS (p < 0.001). Sugammadex has protective and antioxidant properties on cytotoxicity and could be an effective supplement for neurodegenerative diseases such as Alzheimer and Parkinson if further research in vivo supports this claim.

The NMDA receptor antagonists memantine and ketamine as anti-migraine agents

Migraine is a debilitating disorder affecting females more frequently than males. There is some evidence that drugs targeting glutamate receptors: memantine and ketamine might be beneficial in the therapy of this entity. Therefore, the purpose of this work is to present NMDA receptor antagonists, memantine and ketamine, as potential anti-migraine agents. We searched PubMed/MEDLINE, Embase, and clinical trials submitted to ClinicalTrials.gov to find publications describing eligible trials published between database inception and December 31, 2021. This comprehensive literature review summarizes data on the use of the NMDA receptor antagonists memantine and ketamine in the pharmacotherapy of migraine. Results from 20 previous and recent preclinical experiments are discussed and correlated with 19 clinical trials (including case series, open-label, and randomized placebo-controlled trials). For the purposes of this review, the authors hypothesized that the propagation of SD is a major mechanism in the pathophysiology of migraine. In several animal studies and in vitro studies, memantine and ketamine inhibited or reduced propagation of the SD. In addition, the results of clinical trials suggest that memantine or ketamine may be an effective treatment option for migraine. However, most studies on these agents lack control group. Although further clinical trials are needed, the results suggest that ketamine or memantine may be promising molecules for the treatment of severe migraine. Particular attention should be paid to people who have a treatment-resistant form of migraine with aura or have exhausted existing treatment options. For them, the drugs under discussion could represent an interesting alternative in the future.

Potential of Capric Acid in Neurological Disorders: An Overview

To solve the restrictions of a classical ketogenic diet, a modified medium-chain triglyceride diet was introduced which required only around 60% of dietary energy. Capric acid (CA), a small molecule, is one of the main components because its metabolic profile offers itself as an alternate source of energy to the brain in the form of ketone bodies. This is possible with the combined capability of CA to cross the blood-brain barrier and achieve a concentration of 50% concentration in the brain more than any other fatty acid in plasma. Natural sources of CA include vegetable oils such as palm oil and coconut oil, mammalian milk and some seeds. Several studies have shown that CA has varied action on targets that include AMPA receptors, PPAR-γ, inflammatory/oxidative stress pathways and gut dysbiosis. Based on these lines of evidence, CA has proved to be effective in the amelioration of neurological diseases such as epilepsy, affective disorders and Alzheimer's disease. But these studies still warrant more pre-clinical and clinical studies that would further prove its efficacy. Hence, to understand the potential of CA in brain disease and associated comorbid conditions, an advance and rigorous molecular mechanistic study, apart from the reported in-vitro/in-vivo studies, is urgently required for the development of this compound through clinical setups.

Role of nitric oxide on defensive behavior and long-term aversive learning induced by chemical stimulation of the dorsolateral periaqueductal gray matter

The midbrain periaqueductal gray matter, especially the dorsolateral portion (dlPAG), coordinates immediate defensive responses (DR) to threats, but also ascends forebrain information for aversive learning. The synaptic dynamics in the dlPAG regulate the intensity and type of behavioral expression, as well as long-term processes such as memory acquisition, consolidation, and retrieval. Among several neurotransmitters and neural modulators, nitric oxide seems to play an important regulatory role in the immediate expression of DR, but it remains unclear if this gaseous on-demand neuromodulator contributes to aversive learning. Therefore, the role of nitric oxide in the dlPAG was investigated, during conditioning in an olfactory aversive task. The behavioral analysis consisted of freezing and crouch-sniffing in the conditioning day after glutamatergic NMDA agonist injection into the dlPAG. Two days later, rats were re-exposed to the odor cue and avoidance was measured. 7NI, a selective neuronal nitric oxide synthase inhibitor (40 and 100 nmol), injected before NMDA (50 pmol) impaired immediate DR and consequent aversive learning. The scavenging of extrasynaptic nitric oxide by C-PTIO (1 and 2 nmol) induced similar results. Moreover, spermine NONOate, a nitric oxide donor (5, 10, 20, 40, and 80 nmol), produced DR by itself, but only the low dose also promoted learning. The following experiments utilized a fluorescent probe, DAF-FM diacetate (5 µM), directly into the dlPAG, to quantify nitric oxide in the three previous experimental situations. Nitric oxide levels were increased after NMDA stimulation, decreased after 7NI, and increased after spermine NONOate, in line with alterations in defensive expression. Altogether, the results indicate that nitric oxide plays a modulatory and decisive role in the dlPAG regarding immediate DR and aversive learning.

Hallmarks of neurodegenerative diseases

Decades of research have identified genetic factors and biochemical pathways involved in neurodegenerative diseases (NDDs). We present evidence for the following eight hallmarks of NDD: pathological protein aggregation, synaptic and neuronal network dysfunction, aberrant proteostasis, cytoskeletal abnormalities, altered energy homeostasis, DNA and RNA defects, inflammation, and neuronal cell death. We describe the hallmarks, their biomarkers, and their interactions as a framework to study NDDs using a holistic approach. The framework can serve as a basis for defining pathogenic mechanisms, categorizing different NDDs based on their primary hallmarks, stratifying patients within a specific NDD, and designing multi-targeted, personalized therapies to effectively halt NDDs.

Aberrant protein S-nitrosylation contributes to hyperexcitability-induced synaptic damage in Alzheimer's disease: Mechanistic insights and potential therapies

Alzheimer's disease (AD) is arguably the most common cause of dementia in the elderly and is marked by progressive synaptic degeneration, which in turn leads to cognitive decline. Studies in patients and in various AD models have shown that one of the early signatures of AD is neuronal hyperactivity. This excessive electrical activity contributes to dysregulated neural network function and synaptic damage. Mechanistically, evidence suggests that hyperexcitability accelerates production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that contribute to neural network impairment and synapse loss. This review focuses on the pathways and molecular changes that cause hyperexcitability and how RNS-dependent posttranslational modifications, represented predominantly by protein S-nitrosylation, mediate, at least in part, the deleterious effects of hyperexcitability on single neurons and the neural network, resulting in synaptic loss in AD.

Cholesterol metabolism pathway in autism spectrum disorder: From animal models to clinical observations

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by a persistent impairment of social skills, including aspects of perception, interpretation, and response, combined with restricted and repetitive behavior. ASD is a complex and multifactorial condition, and its etiology could be attributed to genetic and environmental factors. Despite numerous clinical and experimental studies, no etiological factor, biomarker, and specific model of transmission have been consistently associated with ASD. However, an imbalance in cholesterol levels has been observed in many patients, more specifically, a condition of hypocholesterolemia, which seems to be shared between ASD and ASD-related genetic syndromes such as fragile X syndrome (FXS), Rett syndrome (RS), and Smith- Lemli-Opitz (SLO). Furthermore, it is known that alterations in cholesterol levels lead to neuroinflammation, oxidative stress, impaired myelination and synaptogenesis. Thus, the aim of this review is to discuss the cholesterol metabolic pathways in the ASD context, as well as in genetic syndromes related to ASD, through clinical observations and animal models. In fact, SLO, FXS, and RS patients display early behavioral markers of ASD followed by cholesterol disturbances. Several studies have demonstrated the role of cholesterol in psychiatric conditions and how its levels modulate brain neurodevelopment. This review suggests an important relationship between ASD pathology and cholesterol metabolism impairment; thus, some strategies could be raised - at clinical and pre-clinical levels - to explore whether cholesterol metabolism disturbance has a generally adverse effect in exacerbating the symptoms of ASD patients.

Toll-Like Receptor 4 Signaling in Neurons Mediates Cerebral Ischemia/Reperfusion Injury

In microglia, Toll-like receptor 4 (TLR4) is well known to contribute to neuroinflammatory responses following brain ischemia. TLR4 is also expressed in neurons and can mediate the conduction of calcium (Ca²⁺) influx, but the mechanistic link between neuronal TLR4 signaling and brain ischemic injury is still poorly understood. Here, primary neuronal cell cultures from TLR4 knockout mice and mice with conditional TLR4 knockout in glutamatergic neurons (TLR4^cKO) were used to establish ischemic models in vitro and in vivo, respectively. We found that deleting TLR4 would reduce the neuronal death and intracellular Ca²⁺ increasement induced by oxygen and glucose deprivation (OGD) or lipopolysaccharide treatment. Infarct volume and functional deficits were also alleviated in TLR4^cKO mice following cerebral ischemia/reperfusion (I/R). Furthermore, TLR4 and N-methyl-D-aspartate receptor subunit 2B (NMDAR2B) were colocalized in neurons. Deletion of TLR4 in neurons rescued the upregulation of phosphorylated NMDAR2B induced by ischemia via Src kinase in vitro and in vivo. Downstream of NMDAR2B signaling, the interaction of neuronal nitric oxide synthase (nNOS) with postsynaptic density protein-95 (PSD-95) was also disrupted in TLR4^cKO mice following cerebral I/R. Taken together, our results demonstrate a novel molecular neuronal pathway in which TLR4 signaling in neurons plays a crucial role in neuronal death and provide a new target for neuroprotection after ischemic stroke.

Cellular response to β-amyloid neurotoxicity in Alzheimer's disease and implications in new therapeutics

β-Amyloid (Aβ) is a specific pathological hallmark of Alzheimer's disease (AD). Because of its neurotoxicity, AD patients exhibit multiple brain dysfunctions. Disease-modifying therapy (DMT) is the central concept in the development of AD therapeutics today, and most DMT drugs that are currently in clinical trials are anti-Aβ drugs, such as aducanumab and lecanemab. Therefore, understanding Aβ's neurotoxic mechanism is crucial for Aβ-targeted drug development. Despite its total length of only a few dozen amino acids, Aβ is incredibly diverse. In addition to the well-known Aβ1-42 , N-terminally truncated, glutaminyl cyclase (QC) catalyzed, and pyroglutamate-modified Aβ (pEAβ) is also highly amyloidogenic and far more cytotoxic. The extracellular monomeric Aβx-42 (x = 1-11) initiates the aggregation to form fibrils and plaques and causes many abnormal cellular responses through cell membrane receptors and receptor-coupled signal pathways. These signal cascades further influence many cellular metabolism-related processes, such as gene expression, cell cycle, and cell fate, and ultimately cause severe neural cell damage. However, endogenous cellular anti-Aβ defense processes always accompany the Aβ-induced microenvironment alterations. Aβ-cleaving endopeptidases, Aβ-degrading ubiquitin-proteasome system (UPS), and Aβ-engulfing glial cell immune responses are all essential self-defense mechanisms that we can leverage to develop new drugs. This review discusses some of the most recent advances in understanding Aβ-centric AD mechanisms and suggests prospects for promising anti-Aβ strategies.

14-3-3 proteins regulate cullin 7-mediated Eag1 degradation

BACKGROUND

Mutations in the human gene encoding the neuron-specific Eag1 (K_V10.1; KCNH1) potassium channel are linked to congenital neurodevelopmental diseases. Disease-causing mutant Eag1 channels manifest aberrant gating function and defective protein homeostasis. Both the E3 ubiquitin ligase cullin 7 (Cul7) and the small acid protein 14-3-3 serve as binding partners of Eag1. Cul7 mediates proteasomal and lysosomal degradation of Eag1 protein, whereas over-expression of 14-3-3 notably reduces Eag1 channel activity. It remains unclear whether 14-3-3 may also contribute to Eag1 protein homeostasis.

RESULTS

In human cell line and native rat neurons, disruptions of endogenous 14-3-3 function with the peptide inhibitor difopein or specific RNA interference up-regulated Eag1 protein level in a transcription-independent manner. Difopein hindered Eag1 protein ubiquitination at the endoplasmic reticulum and the plasma membrane, effectively promoting the stability of both immature and mature Eag1 proteins. Suppression of endogenous 14-3-3 function also reduced excitotoxicity-associated Eag1 degradation in neurons. Difopein diminished Cul7-mediated Eag1 degradation, and Cul7 knock-down abolished the effect of difopein on Eag1. Inhibition of endogenous 14-3-3 function substantially perturbed the interaction of Eag1 with Cul7. Further structural analyses suggested that the intracellular Per-Arnt-Sim (PAS) domain and cyclic nucleotide-binding homology domain (CNBHD) of Eag1 are essential for the regulatory effect of 14-3-3 proteins. Significantly, suppression of endogenous 14-3-3 function reduced Cul7-mediated degradation of disease-associated Eag1 mutant proteins.

CONCLUSION

Overall these results highlight a chaperone-like role of endogenous 14-3-3 proteins in regulating Eag1 protein homeostasis, as well as a therapeutic potential of 14-3-3 modulators in correcting defective protein expression of disease-causing Eag1 mutants.

Reactive oxygen species in status epilepticus

It has long been recognized that status epilepticus can cause considerable neuronal damage, and this has become one of its defining features. The mechanisms underlying this damage are less clear. Excessive activation of NMDA receptors results in large rises in internal calcium, which eventually lead to neuronal death. Between NMDA receptor activation and neuronal death are a number of intermediary steps, key among which is the generation of free radicals and reactive oxygen and nitrogen species. Although it has long been thought that mitochondria are the primary source for reactive oxygen species, more recent evidence has pointed to a prominent role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, an enzyme localized in cell membranes. There is burgeoning in vivo and in vitro evidence that therapies that target the production or removal of reactive oxygen species are not only effective neuroprotectants following status epilepticus, but also potently antiepileptogenic. Moreover, combining therapies targeted at inhibiting NADPH oxidase and at increasing endogenous antioxidants seems to offer the greatest benefits.

Effects of N-methyl-D-aspartate receptor knockdown and hypoxia/reoxygenation injury on the neuronal proteome and transcriptome

Introduction

Brain tissue is extremely sensitive to hypoxia/reoxygenation (H/R) injury, which can easily cause irreversible damage to neurons. H/R injury can induce neuronal apoptosis through glutamate-mediated excitotoxicity. N-methyl-d-aspartate receptor (NMDAR) is one of the main receptors of excitatory glutamate, and blocking NMDAR protects brain tissue from ischemic and hypoxic injury. However, NMDAR hypofunction can also cause psychotic symptoms or cognitive impairment. There is still a lack of systematic research on the changes in the proteome and transcriptome in neuronal cells under conditions of NMDAR hypofunction and H/R injury.

Methods

We compared the changes in the proteome, transcriptome and lncRNA expression levels in neurons after NMDAR knockdown and H/R by isobaric tags for relative and absolute quantitation (iTRAQ) and RNA sequencing (RNA-Seq).

Results

The results showed that the proteins Rps9, Rpl18 and Rpl15 and the lncRNAs XLOC_161072 and XLOC_065271 were significantly downregulated after NMDAR knockdown but upregulated after H/R; in contrast, the mRNAs Bank1 and Pcp4l1 and the lncRNAs XLOC_159404 and XLOC_031922 were significantly upregulated after NMDAR knockdown but downregulated after H/R.

Discussion

In this study, we demonstrated the characterization of protein, mRNA, and lncRNA expression profiles in neurons following NMDAR knockdown and H/R injury. These molecules are involved in multiple biological functions and signaling pathways, and their roles in neurons lacking NMDAR and subjected to H/R injury deserve further study. Additionally, we found that lncRNAs respond fastest to hypoxic stimulation and that Gapdh is not suitable as a reference protein for NMDAR-reduced neuron-related experiments.

Exposure to leucine alters glutamate levels and leads to memory and social impairment in zebrafish

Maple Syrup Urine Disease (MSUD) is a metabolic disorder characterized by high levels in blood and urine of branched-chain amino acids leucine, isoleucine, and valine and their alpha-ketoacids, by a partial or total blockade in the activity of branched-chain complex alpha-keto acids dehydrogenase. The main symptoms in MSUD occur in the central nervous system, including cognitive deficits, locomotor, poor feeding, seizures, psychomotor delay, and mental retardation, but the mechanisms of neurotoxicity and behavior alteration due to this disease are poorly understood, thus this study aimed at showing the effects of leucine exposure on glutamate levels and behavior in zebrafish. For this, we analyzed the behavior using the social preference test and novel object recognition test, moreover, we analyse the glutamate levels and uptake using scintillation and high-performance liquid chromatography methods. Our results demonstrated a decrease in glutamate levels and uptake, accompanied by memory and social impairment. In conclusion, these results suggest that alterations in glutamate levels can be associated with behavior impairment, however, more studies are necessary to understand the mechanisms for brain damage in MSUD.

P2Y1 Receptor as a Catalyst of Brain Neurodegeneration

Different brain disorders display distinctive etiologies and pathogenic mechanisms. However, they also share pathogenic events. One event systematically occurring in different brain disorders, both acute and chronic, is the increase of the extracellular ATP levels. Accordingly, several P2 (ATP/ADP) and P1 (adenosine) receptors, as well as the ectoenzymes involved in the extracellular catabolism of ATP, have been associated to different brain pathologies, either with a neuroprotective or neurodegenerative action. The P2Y1 receptor (P2Y1R) is one of the purinergic receptors associated to different brain diseases. It has a widespread regional, cellular, and subcellular distribution in the brain, it is capable of modulating synaptic function and neuronal activity, and it is particularly important in the control of astrocytic activity and in astrocyte–neuron communication. In diverse brain pathologies, there is growing evidence of a noxious gain-of-function of P2Y1R favoring neurodegeneration by promoting astrocyte hyperactivity, entraining Ca2+-waves, and inducing the release of glutamate by directly or indirectly recruiting microglia and/or by increasing the susceptibility of neurons to damage. Here, we review the current evidence on the involvement of P2Y1R in different acute and chronic neurodegenerative brain disorders and the underlying mechanisms.

Astaxanthin Protection against Neuronal Excitotoxicity via Glutamate Receptor Inhibition and Improvement of Mitochondrial Function

Excitotoxicity is known to associate with neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, Amyotrophic lateral sclerosis and Huntington’s disease, as well as aging, stroke, trauma, ischemia and epilepsy. Excessive release of glutamate, overactivation of glutamate receptors, calcium overload, mitochondrial dysfunction and excessive reactive oxygen species (ROS) formation are a few of the suggested key mechanisms. Astaxanthin (AST), a carotenoid, is known to act as an antioxidant and protect neurons from excitotoxic injuries. However, the exact molecular mechanism of AST neuroprotection is not clear. Thus, in this study, we investigated the role of AST in neuroprotection in excitotoxicity. We utilized primary cortical neuronal culture and live cell fluorescence imaging for the study. Our results suggest that AST prevents neuronal death, reduces ROS formation and decreases the abnormal mitochondrial membrane depolarization induced by excitotoxic glutamate insult. Additionally, AST modulates intracellular calcium levels by inhibiting peak and irreversible secondary sustained calcium levels in neurons. Furthermore, AST regulates the ionotropic glutamate subtype receptors NMDA, AMPA, KA and mitochondrial calcium. Moreover, AST decreases NMDA and AMPA receptor protein expression levels, while KA remains unaffected. Overall, our results indicate that AST protects neurons from excitotoxic neuronal injury by regulating ionotropic glutamate receptors, cytosolic secondary calcium rise and mitochondrial calcium buffering. Hence, AST could be a promising therapeutic agent against excitotoxic insults in neurodegenerative diseases.

Gamma-aminobutyric acid enhances hypoxia tolerance of juvenile Chinese mitten crab (Eriocheir sinensis) by regulating respiratory metabolism and alleviating neural excitotoxicity

With climate change and intensive aquaculture development, environmental hypoxia in aquaculture water has become a common challenge for many aquatic species. Therefore, it is crucial to improve the hypoxic tolerance of animals through nutritional strategies. This study explored the positive role of dietary gamma-aminobutyric acid (GABA) supplementation in enhancing hypoxia tolerance of juvenile Eriocheir sinensis through respiratory regulation and alleviation of hypoxia-induced neural excitotoxicity. Acute hypoxia stress significantly up-regulated the mRNA expression level of hypoxia-inducible factor 1α, oxygen consumption rate and anaerobic respiratory metabolism-related enzyme activities. On the other hand, aerobic respiratory metabolism-related enzyme activities were significantly decreased. However, dietary GABA supplementation remodeled the respiratory metabolism pattern of juvenile crabs exposed to hypoxia stress. In addition, acute hypoxic stress significantly increased the contents of free glutamate and GABA in the nervous tissue. The expression levels of N-Methyl-d-aspartate-related receptor genes and calcium-dependent degradation enzyme-related genes were significantly up-regulated. Similarly, neuronal apoptosis rates, expression levels of apoptosis-related genes, and vesicular glutamate transporter genes were also significantly increased. The high-affinity neuronal glutamate transporter decreased significantly in the crabs exposed to hypoxia stress. However, dietary GABA supplementation could effectively prevent acute hypoxia stress-induced neural excitotoxicity. Furthermore, dietary GABA could significantly improve the redox status in vivo exposed to hypoxia stress. In conclusion, acute hypoxia stress can affect respiratory metabolism and redox state and induce neural excitotoxicity in juvenile E. sinensis. GABA supplementation could improve hypoxia tolerance through multiple physiological regulation pathways.

Targeting NMDA Receptors at the Neurovascular Unit: Past and Future Treatments for Central Nervous System Diseases

The excitatory neurotransmission of the central nervous system (CNS) mainly involves glutamate and its receptors, especially N-methyl-D-Aspartate receptors (NMDARs). These receptors have been extensively described on neurons and, more recently, also on other cell types. Nowadays, the study of their differential expression and function is taking a growing place in preclinical and clinical research. The diversity of NMDAR subtypes and their signaling pathways give rise to pleiotropic functions such as brain development, neuronal plasticity, maturation along with excitotoxicity, blood-brain barrier integrity, and inflammation. NMDARs have thus emerged as key targets for the treatment of neurological disorders. By their large extracellular regions and complex intracellular structures, NMDARs are modulated by a variety of endogenous and pharmacological compounds. Here, we will present an overview of NMDAR functions on neurons and other important cell types involved in the pathophysiology of neurodegenerative, neurovascular, mental, autoimmune, and neurodevelopmental diseases. We will then discuss past and future development of NMDAR targeting drugs, including innovative and promising new approaches.

Amitriptyline Improves Cognitive and Neuronal Function in a Rat Model that Mimics Dementia with Lewy Bodies

Dementia with Lewy bodies (DLB), a highly prevalent neurodegenerative disorder, causes motor and cognitive deficits. The main pathophysiologies of DLB are glutamate excitotoxicity and accumulation of Lewy bodies comprising α-synuclein (α-syn) and β-amyloid (Aβ). Amitriptyline (AMI) promotes expression of glutamate transporter-1 and glutamate reuptake. In this study, we measured the effects of AMI on behavioral and neuronal function in a DLB rat model. We used rivastigmine (RIVA) as a positive control. To establish the DLB rat model, male Wistar rats were stereotaxically injected with recombinant adenoassociated viral vector with the SNCA gene (10μg/10μL) and Aβ (5μg/2.5μL) into the left ventricle and prefrontal cortex, respectively. AMI (10mg/kg/day, i.p.), RIVA (2mg/kg/day, i.p.), or saline was injected intraperitoneally after surgery. From the 29^th day, behavioral tests were performed to evaluate the motor and cognitive functions of the rats. Immunohistochemical staining was used to assess neuronal changes. We measured the α-syn level, number of newborn cells, and neuronal density in the hippocampus and in the nigrostriatal dopaminergic system. The DLB group exhibited deficit in object recognition. Both the AMI and RIVA treatments reversed these deficits. Histologically, the DLB rats exhibited cell loss in the substantia nigra pars compacta and in the hippocampal CA1 area. AMI reduced this cell loss, but RIVA did not. In addition, the DLB rats exhibited a lower number of newborn cells and higher α-syn levels in the dentate gyrus (DG). AMI did not affect α-syn accumulation but recovered neurogenesis in the DG of the rats, whereas RIVA reversed the α-syn accumulation but did not affect neurogenesis in the rats. We suggest that AMI may have potential for use in the treatment of DLB.

Differential Susceptibility of Retinal Neurons to the Loss of Mitochondrial Biogenesis Factor Nrf1

The retina, the accessible part of the central nervous system, has served as a model system to study the relationship between energy utilization and metabolite supply. When the metabolite supply cannot match the energy demand, retinal neurons are at risk of death. As the powerhouse of eukaryotic cells, mitochondria play a pivotal role in generating ATP, produce precursors for macromolecules, maintain the redox homeostasis, and function as waste management centers for various types of metabolic intermediates. Mitochondrial dysfunction has been implicated in the pathologies of a number of degenerative retinal diseases. It is well known that photoreceptors are particularly vulnerable to mutations affecting mitochondrial function due to their high energy demand and susceptibility to oxidative stress. However, it is unclear how defective mitochondria affect other retinal neurons. Nuclear respiratory factor 1 (Nrf1) is the major transcriptional regulator of mitochondrial biogenesis, and loss of Nrf1 leads to defective mitochondria biogenesis and eventually cell death. Here, we investigated how different retinal neurons respond to the loss of Nrf1. We provide in vivo evidence that the disruption of Nrf1-mediated mitochondrial biogenesis results in a slow, progressive degeneration of all retinal cell types examined, although they present different sensitivity to the deletion of Nrf1, which implicates differential energy demand and utilization, as well as tolerance to mitochondria defects in different neuronal cells. Furthermore, transcriptome analysis on rod-specific Nrf1 deletion uncovered a previously unknown role of Nrf1 in maintaining genome stability.

Single-Voxel Proton Magnetic Resonance Spectroscopy of the Thalamus in Idiopathic Epileptic Dogs and in Healthy Control Dogs

The role of magnetic resonance spectroscopy (MRS) in the investigation of brain metabolites in epileptic syndromes in dogs has not been explored systematically to date. The aim of this study was to investigate metabolites in the thalamus in dogs affected by idiopathic epilepsy (IE) with and without antiepileptic drug treatment (AEDT) and to compare them to unaffected controls. Our hypothesis is that similar to humans with generalized epilepsy and loss of consciousness, N-acetyl aspartate (NAA) would be reduced, and glutamate–glutamine (Glx) would be increased in treated and untreated IE in comparison with the control group. In this prospective case–control study, Border Collie (BC) and Greater Swiss Mountain dog (GSMD) were divided into three groups: (1) healthy controls, IE with generalized tonic–clonic seizures with (2) and without (3) AEDT. A total of 41 BC and GSMD were included using 3 Tesla single-voxel proton MRS of the thalamus (PRESS localization, shortest TE, TR = 2000 ms, NSA = 240). After exclusion of 11 dogs, 30 dogs (18 IE and 12 healthy controls) remained available for analysis. Metabolite concentrations were estimated with LCModel using creatine as reference and compared using Kruskal–Wallis and Wilcoxon rank-sum tests. The Kruskal–Wallis test revealed significant differences in the NAA-to-creatine (p = 0.04) and Glx-to-creatine (p = 0.03) ratios between the three groups. The Wilcoxon rank-sum test further showed significant reduction in the NAA/creatine ratio in idiopathic epileptic dogs under AEDT compared to epileptic dogs without AEDT (p = 0.03) and compared to healthy controls (p = 0.03). In opposite to humans, Glx/creatine ratio was significantly reduced in dogs with IE under AEDT compared to epileptic dogs without AEDT (p = 0.03) and controls (p = 0.02). IE without AEDT and healthy controls did not show significant difference, neither in NAA/creatine (p = 0.60), nor in Glx-to-creatine (p = 0.55) ratio. In conclusion, MRS showed changes in dogs with IE and generalized seizures under AEDT, but not in those without AEDT. Based upon these results, MRS can be considered a useful advanced imaging technique for the evaluation of dogs with IE in the clinical and research settings.

Evaluation of the Response to Pulpal Sensibility Tests (Cold, EPT) in Anemic and Healthy Women

Introduction

The prevalence of anemia has been reported high in the female population in Iran. Anemia can be asymptomatic or can present in a variety of symptoms, especially when serum Hb values decrease. The present study would assess dental pulp response to cold and EPT sensibility tests in anemic and healthy women.

Materials and Methods

One hundred twenty maxillary central incisors belonging to participants aged 18–58 years were included in this survey. 60 patients had anemia (Hb ≤ 12.5) with/without medication (30 in each group) and 60 women as controls had no anemia (Hb > 12.5) with/without medication (30 in each group). Electric and cold pulpal sensibility tests were performed for all teeth. Statistical analysis was performed with t-student, Chi-square test, and two-way ANOVA. The significance level was set as p < 0.05.

Results

According to the results of this study, the mean value of hemoglobin in anemic and healthy women was 11.5 and 14.08 g/dl, respectively. The mean value of response to EPT in anemic women with and without medication was 3.21 and 3.14, respectively. The mean value of response to EPT in healthy women with and without medication was 3.81 and 3.58 g/dl, respectively. The mean value of time delay response to cold test was 3.03 and 2.82 s in anemic patients with/without medication. Also, the mean value of time delay response to cold test was 2.80 and 2.93 s in healthy women with/without medication. The pulpal responses to EPT tests had significant differences between anemic and healthy women (p=0.043). There were no significant differences between anemic and healthy women considering time delay response to the cold test (p=0.077).

Conclusion

Based on the results of the present study, tooth response to the EPT  sensibility test may alter in anemic patients despite medication. The evidence from this preliminary study suggests that peripheral neuropathy in anemic patients could affect pulpal sensibility tests.

The Clinical Impact of Methotrexate-Induced Stroke-Like Neurotoxicity in Paediatric Departments: An Italian Multi-Centre Case-Series

Introduction

Stroke-like syndrome (SLS) is a rare subacute neurological complication of intrathecal or high-dose (≥500 mg) Methotrexate (MTX) administration. Its clinical features, evoking acute cerebral ischaemia with fluctuating course symptoms and a possible spontaneous resolution, have elicited interest among the scientific community. However, many issues are still open on the underlying pathogenesis, clinical, and therapeutic management and long-term outcome.

Materials and Methods

We retrospectively analyzed clinical, radiological and laboratory records of all patients diagnosed with SLS between 2011 and 2021 at 4 National referral centers for Pediatric Onco-Hematology. Patients with a latency period that was longer than 3 weeks between the last MTX administration of MTX and SLS onset were excluded from the analysis, as were those with unclear etiologies. We assessed symptom severity using a dedicated arbitrary scoring system. Eleven patients were included in the study.

Results

The underlying disease was acute lymphoblastic leukemia type B in 10/11 patients, while fibroblastic osteosarcoma was present in a single subject. The median age at diagnosis was 11 years (range 4-34), and 64% of the patients were women. Symptoms occurred after a mean of 9.45 days (± 0.75) since the last MTX administration and lasted between 1 and 96 h. Clinical features included hemiplegia and/or cranial nerves palsy, paraesthesia, movement or speech disorders, and seizure. All patients underwent neuroimaging studies (CT and/or MRI) and EEG. The scoring system revealed an average of 4.9 points (± 2.3), with a median of 5 points (maximum 20 points). We detected a linear correlation between the severity of the disease and age in male patients.

Conclusions

SLS is a rare, well-characterized complication of MTX administration. Despite the small sample, we have been able to confirm some of the previous findings in literature. We also identified a linear correlation between age and severity of the disease, which could improve the future clinical management.