Resource equation method for sample size calculation in animal studies

Selenium ameliorates cognitive impairment through activating BDNF/TrkB pathway

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disorder that primarily affects older adults. Selenium, an essential micronutrient for humans, plays a crucial role in the body's normal physiological and metabolic processes. A long-term deficiency in selenium intake can lead to various diseases and even contribute to the ageing process. This study aims to explore the ameliorative effect of selenium on cognitive impairment in 3 × Tg-AD mice and to determine if its effects are related to the BDNF/TrkB pathway.

METHODS

We employed the APP/PS1/tau 3 × Tg-AD mouse model for dietary selenium intervention. Behavioural experiments were conducted to assess learning and memory. Additionally, we measured selenium and GSH-Px levels in whole blood and brain tissue. Neuronal apoptosis in the hippocampus was observed using transmission electron microscopy. The expressions of Aβ, P-tau, BDNF, TrkB, and CREB were measured via RT-qPCR, while the expressions of Aβ, P-tau, BDNF, TrkB, p-CREB, and CREB were quantified using Western blot analysis.

RESULTS

Our findings indicate that selenium supplementation can improve spatial learning and memory deficiencies in 3 × Tg-AD mice. Selenium supplementation increased selenium and GSH-Px levels in the brain tissue of 3 × Tg-AD mice and significantly enhanced neuronal conditions. Furthermore, the expression levels of proteins related to the BDNF/TrkB pathway significantly increased following selenium supplementation.

CONCLUSIONS

Our study demonstrates that selenium can ameliorate memory impairment in 3 × Tg-AD mice by activating the BDNF/TrkB pathway.

The shared mechanism of barrier dysfunction in ulcerative colitis and Alzheimer's disease: DDIT4/IL1β neutrophil extracellular traps drive macrophages-mediated phagocytosis

Ulcerative colitis (UC) and Alzheimer's disease (AD) share a common etiology as inflammatory diseases characterized by barrier deterioration. The aim of this study is to elucidate how neutrophil extracellular traps (NETs), serving as a comorbid etiological factor, can trigger the dysfunction in both the intestinal barrier and blood-brain barrier (BBB). Integrated bioinformatics analysis revealed 14 overlapped NETs-related differential expressed genes in UC and AD, which strongly featured barrier dysfunction. The following verification experiments identified enriched NETs, as well as damaged intestinal epithelium and BBB permeability, in the colon and prefrontal cortex of colitis mice and APP/PS1 mice. By employing pharmacological interventions (Cl-amidine and Disulfiram), we disrupted the formation of NETs and discovered significantly restored barrier integrity and attenuated inflammation. Further enrichment and correlation analysis indicated, for the first time, DDIT4/IL-1β NETs might drive macrophage-mediated phagocytosis to induce barrier dysfunction in UC and AD. Our findings originally established the peripheral-central inflammation interactions of UC and AD from the perspective of NETs, highlighting the potential valuable roles in gut-brain interactions and future clinic translational therapeutics.

Effect of remimazolam toluene sulfonate on the cognitive function of juveniles and its mechanism of action

Remimazolam is a new benzodiazepine. Currently, it remains unclear how repeated exposure to remimazolam affects the cognitive function of the developing brain. In the present study, the equivalent doses of the two sedatives were derived from S-shaped dose-response curves, and the ED95 of remimazolam was 45 mg/kg (95% CI 37.579-79.280), and for midazolam, it was 77 mg/kg (95% CI 63.751-127.21) using probability analysis. Then, we evaluated the effects of remimazolam and midazolam on cognitive function in juvenile mice (C57BL/6) through Y-maze and MWM. TUNEL staining was used to observe the apoptosis of neurons in hippocampus, western blotting was used to detect the expression changes of related proteins, and the changes of LTP were observed by recording the activity of neurons through electrical stimulation. We found that there was no significant difference in the behavior of mice in MWM. However, the short-term memory of developing mice was impaired in Y-maze after repeated exposure to remimazolam and midazolam. Furthermore, our data demonstrated that the short-term memory damage caused by remimazolam is lighter than midazolam. Concurrently, the extent of caspase-3 upregulation, the number of neuronal apoptosis in CA1 and CA3 regions, a downward trend of PSD95 and BDNF in the hippocampus, and the inhibition of LTP were highly consistent with the behavior of short-term memory impairment. These results indicate that the degree of memory impairment caused by remimazolam is milder than that caused by midazolam, making it a potential replacement for midazolam in repeated medication and long-term sedation in children.

Effect of lipid emulsion on vasoconstriction induced by epinephrine or norepinephrine in isolated rat aorta

BACKGROUND

Epinephrine (EPI) or norepinephrine (NOR) is widely used to treat cardiovascular collapse during lipid emulsion (LE) resuscitation for drug toxicity. However, the effect of LE on the vasoconstriction caused by EPI or NOR remains unknown. The purpose of this study was to examine the effect of an LE (Intralipid) on the vasoconstriction caused by EPI and NOR in isolated rat aorta.

METHODS

The effect of LE on the vasoconstriction caused by EPI or NOR in isolated rat aorta was examined. Additionally, the effect of LE on the calcium increase caused by EPI or NOR was investigated. The distribution constant (KD: lipid to aqueous phase) of EPI or NOR between a LE (1%) and an aqueous phase was determined.

RESULTS

LE (1 and 2%) did not significantly alter vasoconstriction caused by EPI or NOR in isolated endothelium-intact aorta. Moreover, the LE did not significantly alter the increased calcium level caused by EPI or NOR. The log KD of EPI in the LE (1%) was -0.71, -0.99, and -1.00 at 20, 50, and 100 mM ionic strength, respectively. The log KD of NOR in the LE (1%) was -1.22, -1.25, and -0.96 at 20, 50, and 100 mM ionic strength, respectively.

CONCLUSIONS

Taken together, the Intralipid emulsion did not alter vasoconstriction induced by EPI or NOR that seems to be due to the hydrophilicity of EPI or NOR, leading to sustained hemodynamic support produced by EPI or NOR used during LE resuscitation.

Mucosal immunization with dual influenza/COVID-19 single-replication virus vector protects hamsters from SARS-CoV-2 challenge

The COVID-19 pandemic has highlighted the need for mucosal vaccines as breakthrough infections, short-lived immune responses and emergence of new variants have challenged the efficacy provided by the first generation of vaccines against SARS-CoV-2 viruses. M2SR SARS-CoV-2, an M2-deleted single-replication influenza virus vector modified to encode the SARS-CoV-2 receptor binding domain, was evaluated following intranasal delivery in a hamster challenge model for protection against Wuhan SARS-CoV-2. An adjuvanted inactivated SARS-CoV-2 whole virus vaccine administered intramuscularly was also evaluated. The intranasal M2SR SARS-CoV-2 was more effective than the intramuscular adjuvanted inactivated whole virus vaccine in providing protection against SARS-CoV-2 challenge. M2SR SARS-CoV-2 elicited neutralizing serum antibodies against Wuhan and Omicron SARS-CoV-2 viruses in addition to cross-reactive mucosal antibodies. Furthermore, M2SR SARS-CoV-2 generated serum HAI and mucosal antibody responses against influenza similar to an H3N2 M2SR influenza vaccine. The intranasal dual influenza/COVID M2SR SARS-CoV-2 vaccine has the potential to provide protection against both influenza and COVID.

Intranasal Single-Replication Influenza Vector Induces Cross-Reactive Serum and Mucosal Antibodies against SARS-CoV-2 Variants

Current SARS-CoV-2 vaccines provide protection for COVID-19-associated hospitalization and death, but remain inefficient at inhibiting initial infection and transmission. Despite updated booster formulations, breakthrough infections and reinfections from emerging SARS-CoV-2 variants are common. Intranasal vaccination to elicit mucosal immunity at the site of infection can improve the performance of respiratory virus vaccines. We developed SARS-CoV-2 M2SR, a dual SARS-CoV-2 and influenza vaccine candidate, employing our live intranasal M2-deficient single replication (M2SR) influenza vector expressing the receptor binding domain (RBD) of the SARS-CoV-2 Spike protein of the prototype strain, first reported in January 2020. The intranasal vaccination of mice with this dual vaccine elicits both high serum IgG and mucosal IgA titers to RBD. Sera from inoculated mice show that vaccinated mice develop neutralizing SARS-CoV-2 antibody titers against the prototype and Delta virus strains, which are considered to be sufficient to protect against viral infection. Moreover, SARS-CoV-2 M2SR elicited cross-reactive serum and mucosal antibodies to the Omicron BA.4/BA.5 variant. The SARS-CoV-2 M2SR vaccine also maintained strong immune responses to influenza A with high titers of anti H3 serum IgG and hemagglutination inhibition (HAI) antibody titers corresponding to those seen from the control M2SR vector alone. With a proven safety record and robust immunological profile in humans that includes mucosal immunity, the M2SR influenza viral vector expressing key SARS-CoV-2 antigens could provide more efficient protection against influenza and SARS-CoV-2 variants.

Icariin ameliorates behavioral deficits and neuropathology in a mouse model of multiple sclerosis

Multiple sclerosis (MS) is a systemic inflammatory illness of the central nervous system that involves demyelinating lesions in the myelin-rich white matter and pathology in the grey matter. Despite significant advancements in drug research for MS, the disease's complex pathophysiology makes it difficult to treat the progressive forms of the disease. In this study, we identified a natural flavonoid compound icariin (ICA) as a potent effective agent for MS in ameliorating the deterioration of symptoms including the neurological deficit score and the body weight in a murine experimental autoimmune encephalomyelitis (EAE) model. These improvements were associated with decreased demyelination in the corpus callosum and neuron loss in the hippocampus and cortex confirmed by immunohistochemistry analysis. Meanwhile, it was observed that the activation of microglia in cerebral cortex and hippocampus were inhibited followed by the neuroinflammatory cytokines downregulation such as IL-1β, IL-6 and TNF-α after ICA treatment, which was probably attributable to the suppression of microglial NLRP3 inflammasome activation. Additionally, molecular docking also revealed the binding force of ICA to NLRP3 inflammasome protein complexes in vitro. Taken together, our findings have demonstrated that ICA, as pleiotropic agent, prevents EAE-induced MS by improving demyelination and neuron loss, which interferes with the neuroinflammation via microglial NLRP3 inflammasome activation.

Metformin and simvastatin exert additive antitumour effects in glioblastoma via senescence-state: clinical and translational evidence

BACKGROUND

Glioblastoma is one of the most devastating and incurable cancers due to its aggressive behaviour and lack of available therapies, being its overall-survival from diagnosis ∼14-months. Thus, identification of new therapeutic tools is urgently needed. Interestingly, metabolism-related drugs (e.g., metformin/statins) are emerging as efficient antitumour agents for several cancers. Herein, we evaluated the in vitro/in vivo effects of metformin and/or statins on key clinical/functional/molecular/signalling parameters in glioblastoma patients/cells.

METHODS

An exploratory-observational-randomized retrospective glioblastoma patient cohort (n = 85), human glioblastoma/non-tumour brain human cells (cell lines/patient-derived cell cultures), mouse astrocytes progenitor cell cultures, and a preclinical xenograft glioblastoma mouse model were used to measure key functional parameters, signalling-pathways and/or antitumour progression in response to metformin and/or simvastatin.

FINDINGS

Metformin and simvastatin exerted strong antitumour actions in glioblastoma cell cultures (i.e., proliferation/migration/tumoursphere/colony-formation/VEGF-secretion inhibition and apoptosis/senescence induction). Notably, their combination additively altered these functional parameters vs. individual treatments. These actions were mediated by the modulation of key oncogenic signalling-pathways (i.e., AKT/JAK-STAT/NF-κB/TGFβ-pathways). Interestingly, an enrichment analysis uncovered a TGFβ-pathway activation, together with AKT inactivation, in response to metformin + simvastatin combination, which might be linked to an induction of the senescence-state, the associated secretory-phenotype, and to the dysregulation of spliceosome components. Remarkably, the antitumour actions of metformin + simvastatin combination were also observed in vivo [i.e., association with longer overall-survival in human, and reduction in tumour-progression in a mouse model (reduced tumour-size/weight/mitosis-number, and increased apoptosis)].

INTERPRETATION

Altogether, metformin and simvastatin reduce aggressiveness features in glioblastomas, being this effect significantly more effective (in vitro/in vivo) when both drugs are combined, offering a clinically relevant opportunity that should be tested for their use in humans.

FUNDING

Spanish Ministry of Science, Innovation and Universities; Junta de Andalucía; CIBERobn (CIBER is an initiative of Instituto de Salud Carlos III, Spanish Ministry of Health, Social Services and Equality).