Anti-neuroinflammatory effect of hydroxytyrosol: a potential strategy for anti-depressant development

Introduction: Depression is a complex psychiatric disorder with substantial societal impact. While current antidepressants offer moderate efficacy, their adverse effects and limited understanding of depression's pathophysiology hinder the development of more effective treatments. Amidst this complexity, the role of neuroinflammation, a recognized but poorly understood associate of depression, has gained increasing attention. This study investigates hydroxytyrosol (HT), an olive-derived phenolic antioxidant, for its antidepressant and anti-neuroinflammatory properties based on mitochondrial protection. Methods: In vitro studies on neuronal injury models, the protective effect of HT on mitochondrial ultrastructure from inflammatory damage was investigated in combination with high-resolution imaging of mitochondrial substructures. In animal models, depressive-like behaviors of chronic restraint stress (CRS) mice and chronic unpredictable mild stress (CUMS) rats were examined to investigate the alleviating effects of HT. Targeted metabolomics and RNA-Seq in CUMS rats were used to analyze the potential antidepressant pathways of HT. Results: HT protected mitochondrial ultrastructure from inflammatory damage, thus exerting neuroprotective effects in neuronal injury models. Moreover, HT reduced depressive-like behaviors in mice and rats exposed to CRS and CUMS, respectively. HT's influence in the CRS model included alleviating hippocampal neuronal damage and modulating cytokine production, mitochondrial dysfunction, and brain-derived neurotrophic factor (BDNF) signaling. Targeted metabolomics in CUMS rats revealed HT's effect on neurotransmitter levels and tryptophan-kynurenine metabolism. RNA-Seq data underscored HT's antidepressant mechanism through the BDNF/TrkB signaling pathways, key in nerve fiber functions, myelin formation, microglial differentiation, and neural regeneration. Discussion: The findings underscore HT's potential as an anti-neuroinflammatory treatment for depression, shedding light on its antidepressant effects and its relevance in nutritional psychiatry. Further investigations are warranted to comprehensively delineate its mechanisms and optimize its clinical application in depression treatment.

TREM2 Alleviates Subarachnoid Hemorrhage-Induced Brain Injury through Attenuating Neuroinflammation and Programmed Cell Death in Vivo and in Vitro

BACKGROUND

Apoptosis and pyroptosis are two types of programmed cell death related to the neuroinflammatory reaction after subarachnoid hemorrhage (SAH). Research indicates that triggering receptor expressed on myeloid cells 2 (TREM2) can regulate the SAH-induced inflammatory response. However, whether TREM2 regulates programmed cell death (apoptosis and pyroptosis) remains to be clarified. The purpose of the present study was to investigate the effects of TREM2 on cell death in SAH.

METHODS

SAH was induced in adult male C57BL/6J mice by endovascular perforation. An in-vitro cellular model of SAH was established by treating cocultured BV2 microglia and HT22 neuronal cells with oxyhemoglobin. TREM2 overexpression or knockdown was carried out by intraventricular lentivirus injection at 7 d before SAH induction in mice or lentiviral transfection, respectively. Neurobehavioral tests as well as western blot, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, Evans blue (EB) staining, Nissl staining, and flow cytometry assays were performed to investigate the neuroprotective role of TREM2 after SAH.

RESULTS

After SAH, the TREM2 mRNA and protein levels were elevated in SAH mice, exhibiting a peak at 72 h. TREM2 overexpression improved the SAH-induced neurological deficits in mice, while TREM2 knockdown worsened them. In the brains of mice with TREM2 overexpression, less neuronal death and more neuronal survival were detected at 72 h post SAH. Meanwhile, TREM2 overexpression showed an inhibitory effect on microglial activation, neutrophil infiltration, and the expression of cell death marker proteins. Consistent results were obtained in vitro.

CONCLUSIONS

Our research indicates the important role of TREM2 on cell death after SAH, suggesting that targeting TREM2 might be an effective approach for treating SAH.

The Neurotherapeutic Arsenal in Cannabis sativa: Insights into Anti-Neuroinflammatory and Neuroprotective Activity and Potential Entourage Effects

Cannabis, renowned for its historical medicinal use, harbours various bioactive compounds-cannabinoids, terpenes, and flavonoids. While major cannabinoids like delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) have received extensive scrutiny for their pharmacological properties, emerging evidence underscores the collaborative interactions among these constituents, suggesting a collective therapeutic potential. This comprehensive review explores the intricate relationships and synergies between cannabinoids, terpenes, and flavonoids in cannabis. Cannabinoids, pivotal in cannabis's bioactivity, exhibit well-documented analgesic, anti-inflammatory, and neuroprotective effects. Terpenes, aromatic compounds imbuing distinct flavours, not only contribute to cannabis's sensory profile but also modulate cannabinoid effects through diverse molecular mechanisms. Flavonoids, another cannabis component, demonstrate anti-inflammatory, antioxidant, and neuroprotective properties, particularly relevant to neuroinflammation. The entourage hypothesis posits that combined cannabinoid, terpene, and flavonoid action yields synergistic or additive effects, surpassing individual compound efficacy. Recognizing the nuanced interactions is crucial for unravelling cannabis's complete therapeutic potential. Tailoring treatments based on the holistic composition of cannabis strains allows optimization of therapeutic outcomes while minimizing potential side effects. This review underscores the imperative to delve into the intricate roles of cannabinoids, terpenes, and flavonoids, offering promising prospects for innovative therapeutic interventions and advocating continued research to unlock cannabis's full therapeutic potential within the realm of natural plant-based medicine.

An early clinical phenotype of necrotizing meningoencephalitis in the Pug reveals similarities to multiple sclerosis in humans

Necrotizing meningoencephalitis (NME) is a fatal neuroinflammatory disease that previously carried a uniformly grave prognosis. Our recent identification of a novel early form of NME in Pugs suggests that disease onset and progression are likely more insidious than previously recognized and provides new hope that early therapeutic intervention may halt disease progression and ultimately prevent or cure NME. This novel perspective also sheds new light on the clinical similarities to multiple sclerosis (MS) in humans and provides a rationale for cross-species translation. The history of recent scientific discoveries in NME and new parallels between MS and NME will be reviewed.

Intra-amniotic inflammation in the mid-trimester of pregnancy is a risk factor for neuropsychological disorders in childhood

OBJECTIVES

Intra-amniotic inflammation is a subclinical condition frequently caused by either microbial invasion of the amniotic cavity or sterile inflammatory stimuli, e.g., alarmins. An accumulating body of evidence supports a role for maternal immune activation in the genesis of fetal neuroinflammation and the occurrence of neurodevelopmental disorders such as cerebral palsy, schizophrenia, and autism. The objective of this study was to determine whether fetal exposure to mid-trimester intra-amniotic inflammation is associated with neurodevelopmental disorders in children eight to 12 years of age.

METHODS

This is a retrospective case-control study comprising 20 children with evidence of prenatal exposure to intra-amniotic inflammation in the mid-trimester and 20 controls matched for gestational age at amniocentesis and at delivery. Amniotic fluid samples were tested for concentrations of interleukin-6 and C-X-C motif chemokine ligand 10, for bacteria by culture and molecular microbiologic methods as well as by polymerase chain reaction for eight viruses. Neuropsychological testing of children, performed by two experienced psychologists, assessed cognitive and behavioral domains. Neuropsychological dysfunction was defined as the presence of an abnormal score (<2 standard deviations) on at least two cognitive tasks.

RESULTS

Neuropsychological dysfunction was present in 45% (9/20) of children exposed to intra-amniotic inflammation but in only 10% (2/20) of those in the control group (p=0.03). The relative risk (RR) of neuropsychological dysfunction conferred by amniotic fluid inflammation remained significant after adjusting for gestational age at delivery [aRR=4.5 (1.07-16.7)]. Of the 11 children diagnosed with neuropsychological dysfunction, nine were delivered at term and eight of them had mothers with intra-amniotic inflammation. Children exposed to intra-amniotic inflammation were found to have abnormalities in neuropsychological tasks evaluating complex skills, e.g., auditory attention, executive functions, and social skills, whereas the domains of reasoning, language, and memory were not affected in the cases and controls.

CONCLUSIONS

Asymptomatic sterile intra-amniotic inflammation in the mid-trimester of pregnancy, followed by a term birth, can still confer to the offspring a substantial risk for neurodevelopmental disorders in childhood. Early recognition and treatment of maternal immune activation in pregnancy may be a strategy for the prevention of subsequent neurodevelopmental disorders in offspring.

Autophagy regulates inflammation in intracerebral hemorrhage: Enemy or friend?

Intracerebral hemorrhage (ICH) is the second-largest stroke subtype and has a high mortality and disability rate. Secondary brain injury (SBI) is delayed after ICH. The main contributors to SBI are inflammation, oxidative stress, and excitotoxicity. Harmful substances from blood and hemolysis, such as hemoglobin, thrombin, and iron, induce SBI. When cells suffer stress, a critical protective mechanism called "autophagy" help to maintain the homeostasis of damaged cells, remove harmful substances or damaged organelles, and recycle them. Autophagy plays a critical role in the pathology of ICH, and its function remains controversial. Several lines of evidence demonstrate a pro-survival role for autophagy in ICH by facilitating the removal of damaged proteins and organelles. However, many studies have found that heme and iron can aggravate SBI by enhancing autophagy. Autophagy and inflammation are essential culprits in the progression of brain injury. It is a fascinating hypothesis that autophagy regulates inflammation in ICH-induced SBI. Autophagy could degrade and clear pro-IL-1β and apoptosis-associated speck-like protein containing a CARD (ASC) to antagonize NLRP3-mediated inflammation. In addition, mitophagy can remove endogenous activators of inflammasomes, such as reactive oxygen species (ROS), inflammatory components, and cytokines, in damaged mitochondria. However, many studies support the idea that autophagy activates microglia and aggravates microglial inflammation via the toll-like receptor 4 (TLR4) pathway. In addition, autophagy can promote ICH-induced SBI through inflammasome-dependent NLRP6-mediated inflammation. Moreover, some resident cells in the brain are involved in autophagy in regulating inflammation after ICH. Some compounds or therapeutic targets that regulate inflammation by autophagy may represent promising candidates for the treatment of ICH-induced SBI. In conclusion, the mutual regulation of autophagy and inflammation in ICH is worth exploring. The control of inflammation by autophagy will hopefully prove to be an essential treatment target for ICH.

Microglia PTK2B/Pyk2 in the Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is a highly hereditary disease with complex genetic susceptibility factors. Extensive genome-wide association studies have established a distinct susceptibility link between the protein tyrosine kinase 2β (PTK2B) gene and late-onset Alzheimer's disease (LOAD), but the specific pathogenic mechanisms remain incompletely understood. PTK2B is known to be expressed in neurons, and recent research has revealed its more important significance in microglia. Elucidating the role of PTK2B high expression in microglia in AD's progression is crucial for uncovering novel pathogenic mechanisms of the disease. Our review of existing studies suggests a close relationship between PTK2B/proline-rich tyrosine kinase 2 (Pyk2) and tau pathology, and this process might be β-amyloid (Aβ) dependence. Pyk2 is hypothesized as a pivotal target linking Aβ and tau pathologies. Concurrently, Aβ-activated Pyk2 participates in the regulation of microglial activation and its proinflammatory functions. Consequently, it is reasonable to presume that Pyk2 in microglia contributes to amyloid-induced tau pathology in AD via a neuroinflammatory pathway. Furthermore, many things remain unclear, such as identifying the specific pathways that lead to the release of downstream inflammatory factors due to Pyk2 phosphorylation and whether all types of inflammatory factors can activate neuronal kinase pathways. Additionally, further in vivo experiments are essential to validate this hypothesized pathway. Considering PTK2B/Pyk2's potential role in AD pathogenesis, targeting this pathway may offer innovative and promising therapeutic approaches for AD.

Effect of Subanesthetic Dose of Esketamine on Perioperative Neurocognitive Disorders in Elderly Undergoing Gastrointestinal Surgery: A Randomized Controlled Trial

Background

Perioperative neurocognitive disorders (PND), including delayed neurocognitive recovery (dNCR) and postoperative cognitive dysfunction (POCD), are common postoperative complications in elderly patients and adversely affect their prognosis. The study was designed to explore the effects of esketamine on postoperative cognitive function in elderly patients who underwent gastrointestinal surgery under general anesthesia and its potential mechanism.

Methods

Eighty-four patients aged 65 and above undergoing gastrointestinal surgery were randomly divided into 2 groups: the esketamine group (group S) and the control group (group C). Group S received intravenous sub-anesthetic doses of esketamine (0.15 mg/kg) 5 minutes before the initiation of surgery, while group C received the same volume of saline. A battery of neuropsychological tests was used to assess cognitive function before surgery, 7 days, and 3 months after surgery. The primary outcome was the incidence of dNCR at 7 days postoperatively and POCD at 3 months postoperatively in both groups. The secondary outcome measures included changes in the levels of serum interleukin-6 (IL-6) and calcium-binding protein β (S100β) before and 1 day after surgery.

Results

The incidence of dNCR in group S was lower than that of group C (18.15% vs 38.24% P=0.033). Contrarily, there was no difference in both groups regarding POCD 3 months postoperatively (6.06% vs 14.37% P=0.247). Plasma IL-6 and S100β levels were significantly elevated in both groups on postoperative day 1 (p<0.05), but esketamine pretreatment reduced these levels to some extent compared with group C (p<0.05).

Conclusion

Sub-anesthetic doses of esketamine might reduce the incidence of dNCR and improve early postoperative cognitive function in elderly patients undergoing gastrointestinal surgery, which might be related to the anti-neuroinflammation effects of esketamine.

Inflammation-related genes and immune infiltration landscape identified in kainite-induced temporal lobe epilepsy based on integrated bioinformatics analysis

BACKGROUND

Temporal lobe epilepsy (TLE) is a common brain disease. However, the pathogenesis of TLE and its relationship with immune infiltration remains unclear. We attempted to identify inflammation-related genes (IRGs) and the immune cell infiltration pattern involved in the pathological process of TLE via bioinformatics analysis.

MATERIALS AND METHODS

The GSE88992 dataset was downloaded from the Gene Expression Omnibus (GEO) database to perform differentially expressed genes screening and weighted gene co-expression network analysis (WGCNA). Subsequently, the functional enrichment analysis was performed to explore the biological function of the differentially expressed IRGs (DEIRGs). The hub genes were further identified by the CytoHubba algorithm and validated by an external dataset (GSE60772). Furthermore, the CIBERSORT algorithm was applied to assess the differential immune cell infiltration between control and TLE groups. Finally, we used the DGIbd database to screen the candidate drugs for TLE.

RESULTS

34 DEIRGs (33 up-regulated and 1 down-regulated gene) were identified, and they were significantly enriched in inflammation- and immune-related pathways. Subsequently, 4 hub DEIRGs (Ptgs2, Jun, Icam1, Il6) were further identified. Immune cell infiltration analysis revealed that T cells CD4 memory resting, NK cells activated, Monocytes and Dendritic cells activated were involved in the TLE development. Besides, there was a significant correlation between hub DEIRGs and some of the specific immune cells.

CONCLUSION

4 hub DEIRGs (Ptgs2, Jun, Icam1, Il6) were associated with the pathogenesis of TLE via regulation of immune cell functions, which provided a novel perspective for the understanding of TLE.

The Isolation and Preparation of Samwinol from Dracocephalum heterophyllum and Prevention on Aβ25-35-Induced Neuroinflammation in PC-12 Cells

Dracocephalum heterophyllum (D. heterophyllum) is a traditional Chinese Tibetan medicine that has been used for the treatment of lymphitis, hepatitis, and bronchitis. However, only a few selected chemical components are currently obtained from D. heterophyllum, which limits its further pharmacological applications. In this study, we have obtained samwinol from D. heterophyllum by medium- and high-pressure liquid chromatography separation for the first time. Thereafter, we investigated the protective actions of samwinol against amyloid beta protein fragment 25-35 (Aβ_25-35) induced neurotoxicity in cultured rat pheochromocytoma PC-12 cells and explored its underlying mechanisms of action. The results indicated that samwinol could increase cell viability and inhibit the production of reactive oxygen species (ROS) and mitochondria-derived ROS, as assessed by MTT assay, Giemsa staining, and flow cytometry assay. Through Western blot analysis, it was found that samwinol substantially inhibited the phosphorylation of ERK(1/2) and promoted the expression of HO-1 and Nrf2. The data obtained from molecular docking were also consistent with the above conclusions. All of these results showed that samwinol from D. heterophyllum can display significant anti-neuroinflammatory and antioxidant activities in vitro, which are associated with the suppression of ERK/AKT phosphorylation and the activation of the Nrf2/HO-1 signaling pathway. In the future, additional in-depth mechanism studies will be carried out to provide more evidence for the potential of samwinol in the treatment of Alzheimer's disease.

Neurobiological Highlights of Cognitive Impairment in Psychiatric Disorders

This review is focused on several psychiatric disorders in which cognitive impairment is a major component of the disease, influencing life quality. There are plenty of data proving that cognitive impairment accompanies and even underlies some psychiatric disorders. In addition, sources provide information on the biological background of cognitive problems associated with mental illness. This scientific review aims to summarize the current knowledge about neurobiological mechanisms of cognitive impairment in people with schizophrenia, depression, mild cognitive impairment and dementia (including Alzheimer's disease).The review provides data about the prevalence of cognitive impairment in people with mental illness and associated biological markers.

l-Theanine ameliorates motor deficit, mitochondrial dysfunction, and neurodegeneration against chronic tramadol induced rats model of Parkinson's disease

Parkinson's disease (PD) is the second most prevalent progressive neurodegenerative disease, characterized by loss of dopaminergic neurons in substantia nigra, with deficiency of dopamine in the striatum. Tramadol is safe analgesic but long-term use confirmed to elevate oxidative stress, neuroinflammation, mitochondrial dysfunction, in brain leads to motor deficits. l-Theanine is an active constituent of green tea which prevents neuronal loss, mitochondrial failure and improves dopamine, gamma-aminobutyric acid (GABA), serotonin levels and in the central nervous system (CNS) via antioxidant, anti-inflammatory, and neuromodulatory properties. In the present study, tramadol was injected intraperitoneally to Wister rats for 28 days at a dose of 50 mg/kg. l-Theanine (25, 50, and 100 mg/kg) was administered orally 3 h before tramadol administration from day 14 to day 28. Behavioral analyses including rotarod, narrow beam walk, open field, and grip strength were used to evaluate motor coordination on a weekly basis. On the day 29, all Wistar rats were sacrificed and striatum homogenates were used for biochemical (lipid peroxidation, nitrite, glutathione, glutathione peroxidase activity, superoxide dismutase, catalase, mitochondrial complex I, IV, and cyclic adenosine monophosphate), neuroinflammatory markers (tumor necrosis factor-α, interleukin-1β, and interleukin-17), and neurotransmitters (dopamine, norepinephrine, serotonin, GABA, and glutamate) analysis. Chronic tramadol treatment caused motor deficits reduced antioxidant enzymes level, increased striatal proinflammatory cytokines release, dysbalanced neurotransmitters, and reduced mitochondrial complex activity I, IV, and cAMP activity. However, l-theanine administration attenuated behavioral, biochemical, neuroinflammatory, neurotransmitters, and mitochondrial activity indicated it as a promising neuroprotective potential against degenerative changes in experimental model of PD.

Mechanisms of neuroplasticity and brain degeneration: strategies for protection during the aging process

Aging is a dynamic and progressive process that begins at conception and continues until death. This process leads to a decrease in homeostasis and morphological, biochemical and psychological changes, increasing the individual’s vulnerability to various diseases. The growth in the number of aging populations has increased the prevalence of chronic degenerative diseases, impairment of the central nervous system and dementias, such as Alzheimer’s disease, whose main risk factor is age, leading to an increase of the number of individuals who need daily support for life activities. Some theories about aging suggest it is caused by an increase of cellular senescence and reactive oxygen species, which leads to inflammation, oxidation, cell membrane damage and consequently neuronal death. Also, mitochondrial mutations, which are generated throughout the aging process, can lead to changes in energy production, deficiencies in electron transport and apoptosis induction that can result in decreased function. Additionally, increasing cellular senescence and the release of proinflammatory cytokines can cause irreversible damage to neuronal cells. Recent reports point to the importance of changing lifestyle by increasing physical exercise, improving nutrition and environmental enrichment to activate neuroprotective defense mechanisms. Therefore, this review aims to address the latest information about the different mechanisms related to neuroplasticity and neuronal death and to provide strategies that can improve neuroprotection and decrease the neurodegeneration caused by aging and environmental stressors.

Activation of silent information regulator 1 exerts a neuroprotective effect after intracerebral hemorrhage by deacetylating NF-κB/p65

Nuclear factor (NF)-κB-mediated neuroinflammation is an important mechanism of intracerebral hemorrhage (ICH)-induced neurotoxicity. Silent information regulator 1 (SIRT1) plays a multi-protective effect in a variety of diseases by deacetylating and inhibiting NF-κB/p65. However, the role of SIRT1 in brain damage following ICH remains unclear. We hypothesized that SIRT1 can protect against ICH-induced brain damage by inhibiting neuroinflammation through deacetylating NF-κB/p65. The ICH model was induced in vivo (with collagenase) and in vitro (with hemoglobin). Resveratrol and Ex527 were administered to activate or inhibit SIRT1, respectively. Western blot, immunohistochemistry, and immunofluorescence assays were performed to detect the expression of SIRT1 and p65. Enzyme-linked immunosorbent assays (ELISAs) were used to explore tumor necrosis factor (TNF)-α and interleukin (IL)-1β release. The neurological score, brain water content, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, and brain hemoglobin content were determined to evaluate the neuroprotective effect of SIRT1. SIRT1 expression was decreased, whereas the level of acetylated p65 (Ac-p65) was elevated after ICH in vivo. Moreover, hemoglobin treatment decreased the expression of SIRT1 in vitro. Activation of SIRT1 by resveratrol had a neuroprotective effect, along with decreased levels of Ac-p65, IL-1β, TNF-α, and apoptosis after ICH. The effect of resveratrol was abolished by the SIRT1 inhibitor Ex527. Our results are consistent with the hypothesis that SIRT1 exerts a neuroprotective effect after ICH by deacetylating p65 to inhibit the NF-κB-dependent inflammatory response.

Neurofilament degradation is involved in laparotomy-induced cognitive dysfunction in aged rats

Excessive neuroinflammatory responses play important roles in the development of postoperative cognitive dysfunction (POCD). Neurofilaments (NFs) were essential to the structure of axon and nerve conduction; and the abnormal degradation of NFs were always accompanied with degenerative diseases, which were also characterized by excessive neuroinflammatory responses in brain. However, it is still unclear whether the NFs were involved in the POCD. In this study, the LC-MS/MS method was used to explore the neuroinflammatory response and NFs of POCD in aged rats. Moreover, trichostatin A (TSA), an inflammation-related drug, was selected to test whether it could improve the surgery-induced cognitive dysfunction, inflammatory responses and NFs. Evident cognitive dysfunction, excessive microglia activation, neuroinflammatory responses and upregulated NFs in hippocampus were observed in the POCD group. TSA pretreatment could significantly mitigate these changes. The KEGG analysis revealed that nine pathways were enriched in the TSA + surgery group (versus the surgery group). Among them, two signaling pathways were closely related with the changes of NFs proteins. In conclusion, surgery could impair the cognitive function and aggravate neuroinflammation and NFs. The TSA could significantly improve these changes which might be related to the activation of the “focal adhesion” and “ECM-receptor interaction” pathways.

Phenolic Glycosides from the Roots of Ficus hirta Vahl. and Their Antineuroinflammatory Activities

Ficus hirta Vahl. (Wuzhimaotao) is an edible functional food used for the soup cooking and health products. Seven undescribed phenolic glycosides (1-7), along with 20 analogues, were isolated from the roots of Ficus hirta. Their structures were determined by comprehensive spectroscopic methods (UV, IR, HRESIMS, and NMR), while the absolute configuration of 1 was established by comparison of the experimental and calculated ECD data. The antineuroinflammatory effects of all the compounds were examined by Western blot. Compounds 1 and 11 attenuated the phosphorylation of AKT, JNK, and ERK1/2. In addition, compound 11 inhibited the NF-κB p65 phosphorylation. Our results indicated that compounds 1 and 11 decreased the occurrence of neuroinflammation in BV2 microglia cells, which might be regulated by inhibiting the activity of proteins in NF-κB, MAPK (JNK and ERK1/2), or AKT signaling pathways. Thus, 1 and 11 might exhibit antineuroinflammatory activities and show promise in treating neurodegenerative diseases.

Silymarin's Inhibition and Treatment Effects for Alzheimer's Disease

As a longstanding problem, Alzheimer's disease (AD) has stymied researchers in the medical field with its increasing incidence and enormous treatment difficulty. Silymarin has always been valued by researchers for its good efficacy and safety in treating liver disease. Recent studies have shown that silymarin also has good pharmacological activity in the nervous system, especially for the treatment of AD. Silymarin can control the production of Aβ by inhibiting the precursor substance of Aβ (β-amyloid precursor protein), and it can inhibit the polymerization of Aβ. Silymarin can also increase the acetylcholine content in the nervous system by inhibiting cholinesterase activity. At the same time, it also has the effect of resisting oxidative stress and the inflammatory response of the nervous system. These pharmacological activities contribute to the inhibition of the onset of AD. The good efficacy of silymarin on AD and its high safety and availability give it huge potential for the treatment of AD.

Neuroprotective potential of ketamine prevents developing brain structure impairment and alteration of neurocognitive function induced via isoflurane through the PI3K/AKT/GSK-3β pathway

Background

The aim of the current experimental study was to scrutinize the neuroprotective effect of ketamine on the isoflurane (iso)-induced cognitive dysfunction in rats via phosphoinositide 3 kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3β (GSK-3β) pathway.

Materials and methods

Sprague-Dawley rats were used for the current experimental study. The rats were divided into six groups and rats were treated with ketamine and memantine. For the estimation of cognitive function study, we used the Morris water test. Pro-inflammatory cytokines such as IL-1β, IL-6, tumor necrosis factor-α (TNF-α), and caspase-6; the antioxidant parameters malondialdehyde, glutathione, superoxide dismutase, catalase, and protein carbonyl; acetylcholinesterase, amyloid β, and brain-derived neurotrophic factor were estimated, respectively. The protein expression of AKT, GSK-3β, p21WAF1/CIP1, and p53 was also estimated, respectively.

Results

Ketamine significantly enhanced cognitive function and showed anti-inflammatory and antioxidant effects, and exhibited the neuroprotective effect of ketamine against the isoflurane-induced cognitive impairment. Additionally, ketamine significantly (P<0.005) suppressed IL-1β, TNF-α, IL-6, caspase-6 and p21WAF1/CIP1, p53 expression and up-regulated the PI3K/AKT/GSK-3β expression in the group of iso-induced rats.

Conclusion

We can conclude that ketamine prevented the cognitive impairment induced by isoflurane anesthesia through anti-apoptotic, anti-inflammatory, and antioxidant effects via the PI3K/AKT/GSK-3β pathway.

The Deacetylase HDAC6 Mediates Endogenous Neuritic Tau Pathology

The initiating events that promote tau mislocalization and pathology in Alzheimer's disease (AD) are not well defined, partly because of the lack of endogenous models that recapitulate tau dysfunction. We exposed wild-type neurons to a neuroinflammatory trigger and examined the effect on endogenous tau. We found that tau re-localized and accumulated within pathological neuritic foci, or beads, comprised of mostly hypo-phosphorylated, acetylated, and oligomeric tau. These structures were detected in aged wild-type mice and were enhanced in response to neuroinflammation in vivo, highlighting a previously undescribed endogenous age-related tau pathology. Strikingly, deletion or inhibition of the cytoplasmic shuttling factor HDAC6 suppressed neuritic tau bead formation in neurons and mice. Using mass spectrometry-based profiling, we identified a single neuroinflammatory factor, the metalloproteinase MMP-9, as a mediator of neuritic tau beading. Thus, our study uncovers a link between neuroinflammation and neuritic tau beading as a potential early-stage pathogenic mechanism in AD.

Octadecylpropyl Sulfamide Reduces Neurodegeneration and Restores the Memory Deficits Induced by Hypoxia-Ischemia in Mice

The PPAR-α agonist, oleoylethanolamide (OEA) has neuroprotective properties in stroke models. However, its rapid degradation represents a limitation for an effective therapeutic approach. In this study, we evaluated the effects of a stable OEA-modeled compound, octadecylpropyl sulfamide (SUL) on the cognitive, behavioral, cellular and molecular alterations associated with hypoxia-ischemia (HI) in mice. Mice subjected to HI were treated with the PPAR-α antagonist GW6471 (GW) (1 mg/kg) followed 15 min later by SUL (3 and 10 mg/kg). Behavioral, motor, and cognitive tests were carried out 24 h and 7 days after the HI. The levels of microglia, reactive astrocytes and neuronal nuclei were studied using immunofluorescence, and the expression of genes related to the N-acyl-ethanolamides/endocannabinoid signaling systems was determined by qRT-PCR at the end of the experimental sequence. HI induced brain damage in the ipsilateral hippocampus and cortex, which lead to severe memory impairments, and motor coordination deficits. Significant neuronal loss, increased microglia and reactive astrocytes, and compensatory changes in genes associated with the inflammation/immune and endocannabinoid systems were observed in these brain structures of lesioned mice. SUL reversed the memory and motor deficits, decreased the overexpression of microglia and astrocytes, and reduced neurodegeneration induced by HI. Cnr1 and Cnr2 gene expression was modulated by SUL in both sham and HI mice, while Pparα and Faah expression was regulated in HI mice. GW completely blocked the beneficial actions of SUL. These findings suggest that treatment with SUL reduces brain damage and the associated motor and memory deficits induced by HI probably by normalizing the changes in neuroinflammation/immune system mediators.

Neural progenitor cells but not astrocytes respond distally to thoracic spinal cord injury in rat models

Traumatic spinal cord injury (SCI) is a detrimental condition that causes loss of sensory and motor function in an individual. Many complex secondary injury cascades occur after SCI and they offer great potential for therapeutic targeting. In this study, we investigated the response of endogenous neural progenitor cells, astrocytes, and microglia to a localized thoracic SCI throughout the neuroaxis. Twenty-five adult female Sprague-Dawley rats underwent mild-contusion thoracic SCI (n = 9), sham surgery (n = 8), or no surgery (n = 8). Spinal cord and brain tissues were fixed and cut at six regions of the neuroaxis. Immunohistochemistry showed increased reactivity of neural progenitor cell marker nestin in the central canal at all levels of the spinal cord. Increased reactivity of astrocyte-specific marker glial fibrillary acidic protein was found only at the lesion epicenter. The number of activated microglia was significantly increased at the lesion site, and activated microglia extended to the lumbar enlargement. Phagocytic microglia and macrophages were significantly increased only at the lesion site. There were no changes in nestin, glial fibrillary acidic protein, microglia and macrophage response in the third ventricle of rats subjected to mild-contusion thoracic SCI compared to the sham surgery or no surgery. These findings indicate that neural progenitor cells, astrocytes and microglia respond differently to a localized SCI, presumably due to differences in inflammatory signaling. These different cellular responses may have implications in the way that neural progenitor cells can be manipulated for neuroregeneration after SCI. This needs to be further investigated.

[Cytokines neuroinflammatory reaction to the action of homoaggregatic and liposomal forms of b-amyloid 1-40 in rats]

An injection model of preclinical stages of Alzheimer's disease has been reproduced in rats. It was accompanied by the decrease in the latent period of conditioned reflex avoidance, increasing levels of endogenous b-amyloid peptide 1-40 and activation of inflammatory cytokines (IL-1b, TNF-a, IL-6, IL-10) in the cerebral cortex, hippocampus and blood serum of experimental animals. We belive that changes identified at the biochemical level are prerequisite to modulate neuronal functions in rats induced by Ab40_Human administration. The toxic effect of exogenous b-amyloid 1-40 homoaggregates caused intense response of the cytokine system, while its liposomal form caused the soft information signal to the activation of innate immunity.