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BACKGROUND:Alzheimer's disease is a degenerative neurological disorder characterized primarily by cognitive impairment.Acupuncture is a kind of traditional Chinese medicine therapy for treating Alzheimer's disease,but its mechanism is not yet clear. OBJECTIVE:To observe the effects of electroacupuncture with"Zhi San Zhen"on the Notch signaling pathway,β-amyloid protein(Aβ)and synaptic plasticity in 5xFAD mice. METHODS:Sixteen male,6-month-old 5xFAD mice,SPF-grade,were randomly divided into the electroacupuncture with"Zhi San Zhen"group(electroacupuncture group)and the model group,with eight mice in each group.Eight SPF-grade,male,6-month-old C57BL/6 mice were used as the wild control(wild)group.The electroacupuncture group received electroacupuncture with"Zhi San Zhen"intervention,5 times a week for 4 consecutive weeks.The model group and the wild group did not receive electroacupuncture intervention.The Morris water maze was used to preliminarily assess their learning and memory abilities.Thioflavin S staining was performed to detect Aβ plaque deposition.Western blot and real-time quantitative polymerase chain reaction(RT-qPCR)were used to measure the expression levels of transmembrane receptor protein Notch-1,Notch 1 intracellular domain(NICD),hairy and enhancer of split 1(Hes 1),hairy and enhancer of split 5(Hes 5),synaptophysin(SYN),postsynaptic density protein-95(PSD-95),and Aβ. RESULTS AND CONCLUSION:Compared with the model group,the wild group and the electroacupuncture group showed shortened escape latency,increased platform crossing times,and longer target quadrant dwell time(P<0.05).Compared with the wild group,the model group had significantly increased deposition of Aβ plaques,while electroacupuncture with"Zhi San Zhen"inhibited the deposition of Aβ plaques in the hippocampus of 5xFAD mice(P<0.05).Compared with the wild group,the model group had decreased mRNA levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5 in the hippocampal tissue of mice,and increased mRNA levels of Aβ(P<0.05).Electroacupuncture with"Zhi San Zhen"increased the mRNA levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5 in the hippocampal tissue,and decreased the mRNA level of Aβ(P<0.05).Compared with the Wild group,the model group had decreased protein expression levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5 in the hippocampal tissue of mice,and increased protein expression levels of Aβ(P<0.05).Electroacupuncture with"Zhi San Zhen"upregulated the protein expression levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5,and inhibited the protein expression of Aβ(P<0.05).To conclude,electroacupuncture with"Zhi San Zhen"can improve the learning and memory abilities of 5xFAD mice,possibly by inhibiting the deposition of Aβ protein and activating the Notch signaling pathway in the hippocampus to enhance synaptic plasticity.
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AIM To investigate the protective effects and the mechanism of the Liuwei Dihuang Pills on mouse brain microvascular endothelial(bEnd.3)cells damaged by β-Amyloid protein1-40(Aβ1-40).METHODS CCK8 method was used to detect the effects of Aβ1-40 and medicated serum of Liuwei Dihuang Pills(MSLDP)on cell activity,and to screen the appropriate concentration.bEnd.3 cells of the control group,the Aβ1-40 group,the MSLDP+Aβ1-40 group and the MSLDP group had their low density lipoprotein-associated protein 1(LRP1),receptor for advanced glycation end products(RAGE),matrix metalloproteinase-2(MMP-2),MMP-9,scaffold protein zonule protein-1(ZO-1)detected by Western blot.bEnd.3 cells assigned into the control group,the Aβ1-40 group,the FPS-ZM1(RAGE inhibitor)+Aβ1-40 group and the FPS-ZM1+Aβ1-40+MSLDP group had their expressions of RAGE,MMP-9,MMP-2 and ZO-1 detected by Western blot as well.RESULTS The cell activity of bEnd.3,was dose-dependently decreased by Aβ1-40(P<0.01),but was protected by MSLDP(P<0.05,P<0.01).And 10 μmol/L Aβ1-40 and 10%MSLDP were selected for subsequent experiments.Compared with the control group,the Aβ1-40 group displayed increased protein expressions of RAGE,MMP-2 and MMP-9(P<0.01),decreased protein expressions of LRP1,ZO-1 and BDNF(P<0.05,P<0.01),and decreased fluorescence intensities of LRP1 and ZO-1(P<0.01).Compared with the Aβ1-40 group,the MSLDP group shared decreased expressions of RAGE,MMP-2,MMP-9 proteins and RAGE fluorescence intensity(P<0.05,P<0.01),and increased expressions of LRP1,ZO-1 and BDNF proteins,and the fluorescence intensity of LRP1 and ZO-1(P<0.05,P<0.01);the Aβ1-40+FPS-ZM1 group displayed decreased protein expressions of MMP-2,MMP9 and RAGE(P<0.05,P<0.01),and increased ZO-1 protein expression(P<0.05);and the Aβ1-40+FPS-ZM1+ MSLDP group displayed an even more decreased protein expressions of MMP-2,MMP9 and RAGE(P<0.01),increased ZO-1 protein expression(P<0.01)due to the the combination use of FPS-ZM1 and MSLDP.CONCLUSION Liuwei Dihuang Pills can protect the tight junction of bEnd.3 injured by Aβ1-40 and neurovascular units from Alzheimer's disease by alleviating the dysfunction of the blood-brain barrier via RAGE-mediated MMP-2/MMP-9 pathway inhibition.
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Alzheimer's disease （AD） is the most common form of senile dementia， and its pathogenesis is still unclear. While β-amyloid （Aβ） is considered an important cause of AD， the pathological mechanism of Aβ inducing AD is subject to various controversies. Recent studies have shown that the myeloid cell trigger receptor （TREM2） plays an important role in the pathological process of AD， and it can not only serve as an important receptor for the internalization of Aβ but also become a biological diagnostic biomarker and therapeutic target. Hence， elucidating the structure and function of TREM2 will provide important ideas for the prevention and treatment of AD. This article will provide a systematic review of the structure of TREM2， its impact on microglial cell function， its pathological role in AD， and the current status of targeted TREM2 therapy for AD. These summaries will provide valuable references for basic research on AD.
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A series of phthalimide-donepezil (PTA-DPZ) hybrids (5a-e, 6a-l) were designed, synthesized and evaluated as selective inhibitors of acetylcholinesterase (AChE). The results showed that some hybrids had strong AChE inhibitory activity with half maximal inhibitory concentration (IC50) at nanomolar range, which was better than the control drugs galanthamine and tacrine, and equivalent to DPZ. Compound 6k exhibited the strongest inhibition to AChE with an IC50 value of 0.13 μmol·L-1. Kinetic and molecular modeling studies showed that 6k targeted both catalytic active site and peripheral anionic site of AChE. Moreover, some compounds could inhibit AChE-induced β-amyloid (Aβ) aggregation. In addition, absorption, distribution, metabolism and excretion prediction results showed 6k conforms to the Lipinski's rule of five and had high partition coefficient P value. These compounds, especially 6k, may be considered as a dual-functional lead compound for in-depth research.
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Alzheimer's disease(AD)is a disease with clinical manifestations of learning and memory impairment,cognitive dysfunction,and language dysfunction,the pathogenesis of AD is complex,of which Aβ theory covers various mechamisms such as oxidative stress,inflammation,apoptosis and other mechanisms.Based on the Aβ mechanism and related signaling pathways,this study discusses the overview of typical Chinese medicines and their active ingredients in the prevention and treatment of AD.The aim is to provide insights and references for the development of traditional Chinese medicines for the prevention and treatment of AD.
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Objective:To explore the mechanism of olfactory three needle therapy on Parkinson's disease dementia(PDD)by observing its effects on expression of apolipoprotein E(ApoE)、glial fibrillary acidic protein(GFAP)and related core pathology substrates in the hippocampus of PDD model mice. Method:Male C57BL/6 mice were randomly divided into four groups:control group(Control),sham opera-tion group(Sham),model group(Model)and acupuncture electrotherapy group(AE),with 10 mice in each group.The PD model was established by injecting 6-OHDA into the medial forebrain tract(MFB)and PDD mice were selected.After successful modeling and selection,the AE group received"olfactory three needle"electro acupuncture treatment.After 14 days of intervention,Morris water maze test and shuttle box test were used to evaluate the learning and memory ability of mice in each group.Hematoxylin-eosin(HE)staining was used to observe the pathological changes of hippocampal CA1 region.Western blotting was used to detect the expression of α-syn,Aβ and ApoE proteins in hippocampal CA1 region.The co-location rate of ApoE and GFAP in hippocampal CA1 region was observed by double immunofluorescence markers. Result:Compared with Model group,the AE group exhibited a shortened escape latency in water maze(P＜0.01),increased platform crossing(P＜0.05),increased active escape times of shuttle box(P＜0.05),and reduced the average total time of electric stimulation(P＜0.01).In the Model group,the neurons in the hippocampal CA1 area were sparsely arranged and showed signs of degeneration and necrosis;and cell nuclei were small,hyperchromatic and had unclear structures,indicating the appearance of nuclear pyrosis.In contrast,the AE group showed significant improvements in neuronal pathology,with most cells regularly arranged,round and large nuclei,lightly stained and clearly shaped.Compared with the Model group,the expression levels of α-syn,Aβ,ApoE protein and the co-localization rate of ApoE and GFAP in hippocampal CA1 region in AE group were decreased(P＜0.01,P＜0.01,P＜0.01,P＜0.05). Conclusion:The"Olfactory three needle"acupuncture can improve the cognitive ability and restore the morpho-logical structure and function of neurons in PDD mice.The mechanism may be related to the inhibition of ApoE expression in astrocytes and the reduction of α-syn and Aβ deposition in hippocampal CA1 region.
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Objective:To explore the correlations of brain network functional connectivity (FC) alterations with cerebrospinal fluid (CSF) pathological biomarkers in patients with Alzheimer's disease (AD).Methods:A total of 39 patients with cognitive impairment, admitted to Department of Neurology, Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2020 to December 2022 were recruited; 23 patients were with AD and 16 with non-AD. Clinical data were compared between the 2 groups. Resting-state functional MRI (rs-fMRI) data were collected, and FC differences between brain networks and FC differences within brain networks were compared by independent component analysis. Correlations of FC differences between brain networks and FC differences within brain networks with concentrations of β-amyloid protein 1-42 (Aβ 1-42) and Tau protein in CSF were analyzed. Results:Compared with the non-AD group, AD group had significantly lower Aβ 1-42 in CSF ( P<0.05). Compared with those in the non-AD group, FC alterations between the left frontoparietal network (lFPN) and anterior default mode network (aDMN) and between the visual network (VN) and posterior cingulate cortex (PCC), as well as FC alterations in lFPN, were significantly increased in AD group ( P<0.05). Compared with those in the non-AD group, FC alterations between lFPN and cerebellar network (CEN), and FC alterations in aDMN, sensorimotor network (SMN) and VN were significantly decreased in AD group ( P<0.05). In AD group, FC in SMN was positively correlated with total Tau and phosphorylated-Tau181 in CSF ( P<0.05); FC between VN and PCC was positively correlated with total Tau in CSF ( P<0.05). CSF Aβ 1-42 was positively correlated with FC alterations in aDMN and VN, but negatively correlated with FC in FPN ( P<0.05). Conclusion:In AD patients, characteristic changes in FC within and between multiple brain networks are noted, which are related to changes of Tau protein and Aβ 1-42 in CSF.
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ObjectiveTo reveal the effects of Huanglian Jiedutang （HLJDT） on the learning and memory abilities of APP/PS1 transgenic mice via hypoxia-inducible factor-1α （HIF-1α）/vascular endothelial growth factor （VEGF） signaling pathway. MethodForty 5-month-old β-amyloid precursor protein （APP）/presenilin 1（PS1） mice were randomized into the model， donepezil （0.001 g·kg-1·d-1）， and low-， medium-， and high-dose （1.5， 3， 6 g·kg-1·d-1， respectively） HLJDT groups， and 8 C57BL/6 mice were taken as the normal group. After 45 days of continuous administration， Morris water maze test was conducted， and the organ indexes were calculated. The morphological structure of cerebral vascular endothelial cells in mice was observed under a transmission electron microscope. Western blot was employed to measure the protein levels of APP， HIF-1α， VEGF，VEGFA， and brain-derived neurotrophic factor （BDNF） in the hippocampus. The mRNA levels of APP， HIF-1α， and VEGF were determined by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultCompared with the normal group， the model group showed prolonged escape latency （P<0.05）， reduced distance and time around the target platform （P<0.05）， decrease brain and spleen indexes （P<0.05）， vascular endothelial cells with karyopyknosis and not abundant cytoplasm， up-regulated protein levels of APP， HIF-1α， VEGF， and VEGFA （P<0.05）， down-regulated protein level of BDNF （P<0.05）， and up-regulated mRNA levels of APP， HIF-1α， and VEGF （P<0.05） in the hippocampus. Compared with the model group， high-dose HLJDT shortened the escape latency （P<0.05）， increased the distance and time around the target platform （P<0.05）， raised the brain and spleen indexes （P<0.05）， repaired the organelles of vascular endothelial cells， down-regulated the protein levels of APP， HIF-1α， VEGF， and VEGFA （P<0.05）， up-regulated the protein level of BDNF （P<0.05）， and down-regulated the mRNA levels of APP， HIF-1α， and VEGF （P<0.05） in the hippocampus. ConclusionHLJDT can improve the learning and memory abilities of mice by reducing the expression of HIF-1α and VEGF， thus protecting the nerves.
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Based on the correlation between Qi and blood in traditional Chinese medicine， the collateral disease theory puts forward that the Qi-collateral go hand in hand with the vessel-collateral of the brain， and to be as close as lips to teeth in structure and function， which is an important basis for the function of brain governing mind. And this theory proposes that deficiency/stagnancy of collateral-Qi， stagnation of collaterals and loss of consciousness are the main pathogenesis of Alzheimer's disease（AD）， which is different from the research strategy of modern medicine focusing on neurons. It is suggested that it is necessary to treat AD from two aspects， including neuronal protection（elimination of pathological products such as β-amyloid and phosphorylated tau protein） and cerebral microvascular protection（protection of cerebral microvascular structure and function， promotion of therapeutic angiogenesis and increase of cerebral blood flow. Tongxinluo capsules is a representative drug for dredging collaterals developed under the guidance of the therapeutic principle of collaterals need circulation， it can protect microvessels and play a neuroprotective role mediated by vascular protection. Clinical studies have confirmed that Tongxinluo capsules can effectively treat AD， vascular dementia and cognitive impairment related diseases， which can provide new ideas and effective treatment ways to prevent and treat AD from neurovascular protection in a comprehensive manner.
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【Objective】 To explore the risk of Alzheimer′s disease (AD) transmitted by blood transfusion. 【Methods】 There were 10 APP/PS1 mice of 3, 6 and 9 months old, half female and half male, and the cognitive and behavioral abilities of C57 mice of the same age were measured, and the blood of the oldest APP/PS1 mice with no behavioral changes were collected to detect the contents of Aβ40 and Aβ42. The polymers Aβ40 and Aβ42 were prepared and Western blotting analysis was conducted. Kunming mice aged from 6 to 7 months were randomly divided into 6 groups (10 mice/ group, half male and half female). The blood of APP/PS1 mice was injected intravenously in experimental group 1-2(100 μL/mouse) with high frequency injection (3 times/week) and low frequency injection (1 time/week), respectively. In experimental group 3-4, Aβ40 and Aβ42 polymerized mixture (100 μL/mouse) were injected in high frequency and low frequency, respectively. The control group 1-2 was injected with the same amount of normal saline, with high frequency and low frequency, respectively. The above groups were injected for 4 weeks, and the cognitive and behavioral abilities were tested and analyzed one week after injection. Finally, the contents of Aβ40 and Aβ42 in blood of Kunming mice were detected. 【Results】 Change in cognitive and behavioral ability showed in 9 months old APP/PS1 mice, but not in 3 and 6 months old APP/PS1 mice. The contents of Aβ40 and Aβ42 (pg/mL) in blood of 6-7 months old APP/PS1 mice were 418.40±2.18 and 15.68±0.20, respectively. Except for monomers, most of the polymerized mixtures of Aβ40 and Aβ42 were dimers and trimers. In both high frequency and low frequency, Kunming mice transfused with blood of APP/PS1 mice (experimental group 1-2) showed a certain degree of anxiety-like behavior and short-term memory shortening in open-field test and conditioned fear test, but without significant difference. There was no significant difference in open field test, new object recognition, Barnes maze and cognitive behavior analysis of conditioned fear between experimental group 3-4 and the control group. The levels of blood Aβ40 and Aβ42(pg/mL) of Kunming mice detected by ELISA were 10.30±0.08 and 3.360±0.005, respectively, and there was no significant difference between the two groups. 【Conclusion】 Blood transfusion of APP/PS1 mice and the mixture of Aβ40 and Aβ42 have no significant effect on the cognitive function of healthy Kunming mice in a short time, and the risk of AD transmission is relatively low.
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Objective To investigate effect of plasma ammonia on β-amyloid(Aβ)of CSF and cognitive function in mild Alzheimer's disease(AD).Methods A total of 108 mild AD patients admitted to our hospital and 47 volunteers(HC group)were studied,the cognitive function were measured and plasma ammonia were detected.The mild AD patients were divided into normal ammonia group(ADA-group)and hyperammonemia group(ADA + group)by the plasma ammonia level.The level of Aβ42,Aβ40,total tau and phosphorylated tau protein in CSF of AD patients were detected,and the results were compared.Results Compared with HC group,the MMSE and Montreal Cognitive Assessment(MoCA)in the ADA-group and ADA + group were significantly lower(all P＜0.001).The MoCA of ADA + group was significantly lower than that of ADA-group(P＜0.001).The plasma ammonia of ADA + group were significantly higher than those of ADA-group and HC group(all P＜0.001).The levels of Aβ42 and Aβ40 in ADA + group were significantly lower than those of ADA-group(t =2.29,P =0.024;t =2.72,P =0.008).In ADA + group,the plasma ammonia level was negatively correlated with the MoCA score(r =-0.47,P＜0.001)and level of Aβ42 in CSF(r =-0.63,P＜0.001).The level of Aβ42 played a partial mediating role between the plasma ammonia level and cognitive function,and mediating effect accounted for 45.94%of the total effect.Conclusion The plasma ammonia level is elevated in some AD patients,high plasma ammonia level may reduce the Aβ42 level in CSF,contributes to Aβ42 deposition which forms the amyloid plaques,ultimately aggravates cognitive impairment.
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Objective To explore the effect and possible mechanism of petroleum ether extract from Gastrodia elata on A amyloid β-protein deposition in Caenorhabditis elegans(C.elegans).Methods C.elegans was used as the model organism,and the experiment was divided into blank group(Control group),GEPEE 0.5 mg·mL-1 group and GEPEE 1 mg·mL-1 group.The effects of GEPEE on paralysis,life span,oxidative stress,heat stress,reactive oxygen species(ROS)level and Aβ aggregation of C.elegans were investigated,qRT-PCR was used to detect the changes of gene expression related to insulin/IGF-1 signaling pathway(IIS)in C.elegans.The main components were analyzed by high performance liquid chromatography(HPLC).Results Compared with Control group,GEPEE could significantly improve the paralysis phenotype of C.elegans(P<0.01),prolong the lifespan of C.elegans(P<0.01),enhance the motility of C.elegans(P<0.01),and increased the resistance to external oxidative stress(P<0.01),the stress ability of high temperature(P<0.01),improved the deposition of Aβ in vivo(P<0.01),decreased the ROS content in C.elegans(P<0.01),decreased the expression levels of Aβ and DAF-2(P<0.01),increased the expression levels of DAF-16 and its target genes SOD-3,GSH-Px,HSF-1 and its target gene HSP-16.2,SKN-1 and its target gene GST-4(P<0.01).Its main components were p-hydroxybenzyl alcohol and p-ethoxylbenzyl alcohol by HPLC.This study showed that GEPEE can reduce Aβ-induced toxicity in CL4176 C.elegans by reducing ROS level in vivo,increasing antioxidant level and regulating IIS pathway.Conclusion GEPEE can inhibit the toxicity of Aβ protein,and its mechanism is related to the regulation of IIS signaling pathway.
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Objective:To investigate the effect of dapagliflozin on cognitive function in middle-aged and elderly type 2 diabetes mellitus patients and related factors.Methods:This was a retrospective study. A total of 200 patients who were hospitalized in the Department of Endocrinology, the Second Affiliated Hospital of Anhui Medical University from August 2021 to August 2022 were recruited randomly. They were divided into the dapagliflozin group and control group. Clinical data were collected; plasma levels of β-amyloid protein(Aβ) 40 and Aβ42 were measured. The Montreal cognitive assessment(MoCA) and the mini-mental state examination(MMSE) were employed to assess cognitive function in both groups. Based on MoCA scores, patients in the dapagliflozin group were further categorized into mild cognitive impairment(MCI) and non-MCI subgroups. Differences among groups were analyzed and compared using t-test, χ2 test, and Mann-Whitney U test, and multivariable logistic regression was used to identify relevant factors associated with cognitive impairment in diabetes patients. Results:Compared to the control group, the dapagliflozin group exhibited significant increases in MMSE and MoCA scores, estimated glomerular filtration rate, and plasma concentration Aβ40(all P<0.05); And the incidence of MCI, homeostasis model assessment for insulin resistance(HOMA-IR), total cholesterol, triglycerides, urine albumin creatine ratio, plasma Aβ42, and Aβ42/Aβ40 ratio were significantly decreased(all P<0.05). Compared with the MCI subgroup, duration of dapagliflozin treatment in the non-MCI subgroup were significantly increased( P<0.05); There were statistically significant decreased in the non-MCI subgroup in age, systolic blood pressure, fasting plasma C-peptide, and HOMA-IR(all P<0.05). Multivariable logistic regression analysis showed that duration of dapagliflozin treatment was a protective factor for cognitive dysfunction( OR=0.322, 95% CI 0.150-0.692, P=0.004) and the age and HOMA-IR were risk factors( OR=1.109, 95% CI 1.014-1.212, P=0.023; OR=3.376, 95% CI 1.276-8.931, P=0.014). Conclusion:Dapagliflozin may improve cognitive function and significantly reduce the incidence of MCI in middle-aged and elderly patients with type 2 diabetes mellitus, possibly associated with the improvement of insulin resistance.
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Objective:To establish and validate an LC-MS/MS method for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in cerebrospinal fluid. Additionally, the consistency between this method and three mainstream detection methods was evaluated.Methods:This study involved method establishment, validation, and consistency evaluation. The N15 labeled β-amyloid protein was used as the internal standard. Extraction was performed using Waters MCX 96-wells solid phase extraction plate, and the eluent was collected to QuanRecovery MaxPeak 700 μl plate. At the positive ion mode, the multi-reaction ion monitoring mode based on electric spray ionization is chosen for the determination of CSF Aβ 1-42, Aβ 1-40, and Aβ 1-38. Referring to the CLSI C62-A and EP-15A3 guidelines, the method is evaluated and verified, including quantitation of limit (LOQ), linearity, recovery, precision, and accuracy. In addition, a total of 57 clinical residual CSF samples were collected and the concentrations of Aβ 1-42 and Aβ 1-40 were determined based on manual INNOTEST ELISA assay and Lumipulse G and Roche Elecsys fully automated biochemical analyzers. The comparison analysis and deviation evaluation were conducted by passing-bablok and Bland Altman methods.Results:The analysis time of this method is 8 min, and the LOQ of Aβ 1-42, Aβ1-40 and Aβ1-38 is 0.1 ng/ml, 0.5 ng/ml, and 0.1 ng/ml, respectively, and the linear range can meet the needs of clinical detection. Respectively, the recovery is 86.2%-93.8%, 100.9%-103.9% and 103.3%-107.1%; the total imprecision is 4.7%-7.4%, 3.5%-4.6% and 5.2%-10.9%. The measured values of Aβ 1-42 certified reference materials are all within the allowable uncertainty requirements. Moreover, the carryover rate of three analytes was all≤0.11%. In addition, the correlations of Aβ 1-42 and Aβ1-40 in CSF between this LC-MS/MS method and the INNOTEST ELISA method, Lumipulse G and Roche Elecsys fully automated biochemical analyzers were all deemed good, with correlation coefficient (r) ranging from 0.920 to 0.970. However, the measured values between the four methods were remarkably different.Conclusion:We established and validated a robust method based on LC-MS/MS technology for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in CSF. The method is accurate, simple, and suitable for clinical measurements. However, despite good correlations, there were substantial differences in the measurement results of Aβ 1-42 and Aβ 1-40 among different analytical platforms, indicating the need for further promotion of harmonization and standardization processes for AD classic biomarkers.
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Microglia, the main immune macrophages in the central nervous system, can be highly involved in the occurrence and development of Alzheimer's disease(AD)through microglia polarization and receptor protein expression. Traditional Chinese Medicine has been demonstrated to have regulatory effects on MG. Many active components in Traditional Chinese herbs play important roles in decreasing β-amyloid peptide(Aβ)accumulation, inhibiting neuro-inflammation and regulating microglia polarization etc. In this study the role of microglia in the pathogenesis of AD and the mechanism by which Traditional Chinese Medicine regulating microglia are reviewed to provide a reference for the treatment of AD.
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[Abstract] Objective To study the effects of pranlinide on cognitive behavior, β amyloid(Aβ) protein 6E10, inflammatory factors and neuronal cell morphology in brain and retina of 5×FAD mice and WT mice. Methods Thirty two 5×FAD mice and 16 WT mice were selected. All were female. 5×FAD mice were randomly divided into blank group and treatment group; No treatment was given in WT group. Blank group was intraperitoneally injected with PBS; treatment group was received intraperitoneal injection of pranlinide once a day for 8 weeks. The changes of cognitive ability were measured by Morris water maze test. The expression of Aβ6E10 protein in mice hippocampal cells and retina was detected by immunohistochemistry. Tumor necrosis factor α(NF-α) was determined by enzyme-linked immunosorbent assay. The same method was also used for interleukin-1β(IL-1β) detection (The content of inflammatory factors). The arrangement and morphology of nerve cells in mouse hippocampal tissue were determined by hematoxylin-eosin (HE) staining. Results The latency time of treatment group was shorter than that of 5×FAD group,and the times of crossing the platform and the percentage of target quadrant stay in the treatment group were higher than those in the 5×FAD group, and the differences were statistically significant (P0. 05). Compared with the 5×FAD group, the nerve cells in the treatment group were arramged in order and clear relatively. The distribution of glial cells was concentrated; The surrounding clearance was small. Conclusion Pranlinide can improve the cognitive ability of mice. The arrangement of nerve cells is regular, the shape is regular and the boundary is clear; The distribution of glial cells is concentrated; surrounding of clearance decrease. Aβ6E10 is synchronized in brain and retina.
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Objective:To study the effect of β-amyloid(Aβ) on calcium homeostasis and endoplasmic reticulum calcium storage of hippocampal neurons in rats.Methods:A total of 60 adult male SD rats were randomly divided into six groups by body mass matching method, with 10 rats in each group.Three groups were injected Aβ 25-35 into the hippocampus(2 μL per side), and divided into low dose group(2.5 μg/μL), medium dose group(5.0 μg/μL) and high dose group(7.5 μg/μL) respectively, and the other 3 groups were set up as the normal saline group(2 μL 0.9% sodium chloride solution), sham-operated group(rats craniotomy without injection) and normal control group(normal feeding without any treatment). The rats were fed until 14 days after operation, and the behavior and state of the rats were observed and recorded, as well as the body weight and total food intake ratio.And the rat hippocampal cells endoplasmic reticulum pathological change were observed by using the electron microscope and light microscope, meanwhile the concentration of intracellular free Ca 2+ ions was detected by the laser scanning confocal microscope and the expression level of PS, SERCA and RyR mRNA and protein by real-time PCR and Western blot methods respectively.The experimental results were analyzed using SPSS 25.0 software for statistical analysis. Repeated measurement ANOVA and one-way ANOVA were used for multi-group comparison, and Dunnett test and Tukey test were used for further pairwise comparison. Results:(1) The body weight of rats in each group was analyzed by repeated measurement ANOVA, and the difference of time effect was statistically significant( F=153.15, P<0.001), but there was no significant difference between the intergroup effects and interaction effects( F=1.547, P=0.374; F=1.598, P=0.113). The body weight of high, medium and low dose Aβ 25-35 groups at 7, 14 days after injection had no significant difference compared with the control group(all P>0.05). The food utilization rates of the high, medium and low doses of Aβ 25-35 groups were(22.9±4.0)%, (23.0±4.2)% and(22.6±3.2)%, respectively, and there was no significant difference compared with the control group((23.7±5.0)%, P>0.05). Within 14 days after injection, listlessness and lethargy were observed in rats in the high dose Aβ 25-35 group.(2) Pathological observation results showed that the endoplasmic reticulum of rat hippocampal cells in the high dose and medium dose groups of Aβ 25-35 was expanded and swelled, and the mitochondria were swollen and deformed.(3) 14 days after Aβ 25-35 injection, the fluorescence intensity of free calcium in hippocampus of rats in high, medium and low dose groups were(820.43±6.89), (720.12±4.30) and (680.50±4.32), respectively, which were all higher than that in the control group(592.17±3.97)(all P<0.001). (4) RT-PCR and Western blot results showed that compared with the control group, high dose and medium dose Aβ 25-35 injection could up-regulate the expression of PS and SERCA mRNA and protein in hippocampal cells(all P<0.05), while down-regulate the expression of RyR mRNA and protein in hippocampal cells(all P<0.05). Conclusion:The deposition of Aβ 25-35 in hippocampal tissues can disrupt the homeostasis of calcium ions in hippocampal tissues, and then cause the increase of free calcium and its related proteins, thus playing the neurotoxic role.
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Mitochondrial oxidative stress has been recognized as a preliminary and critical factor that aggravates the pathological cascade of Alzheimer's disease, which induces the production of β-amyloid protein, upregulates the expression of phosphorylated tau protein and triggers oxidative damage to lipids, proteins and mitochondrial deoxyribonucleic acid. Central neurons are more vulnerable to oxidative stress than non-neuronal cells due to their high oxygen demand, abundant unsaturated fatty acids and antioxidant enzymes deficiency. On this account, this review introduces the causes of mitochondrial oxidative stress, and analyzes the important role of mitochondrial oxidative stress in the pathogenesis of Alzheimer's disease. Meanwhile, the review focuses on the design and intervention strategies of drug delivery systems targeting mitochondrial oxidative stress in neurons, aiming to provide new ideas for the prevention and treatment of Alzheimer's disease.
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Cerebral amyloid angiopathy-related inflammation is an inflammatory reaction process caused by beta-amyloid protein deposited in the cortical and leptomeningeal vessels, which is a rare type of cerebral amyloid angiopathy. Most of the patients are middle-aged and elderly, and manifest as progressive cognitive impairment, headache, seizures, and focal neurological deficits. Brain magnetic resonance imaging shows asymmetric T 2/fluid attenuated inversion recovery hyperintensity in cortical and subcortical white matter, in addition to multiple cerebral microbleeds. The disease often needs to be differentiated from primary angiitis of the central nervous system, glioma, and varicella-zoster virus encephalitis. Although the disease is rare, prompt treatment with glucocorticoids and immune suppressants can reduce death and disability and significantly improve outcome. Therefore, it is necessary to improve the ability of early diagnosis and treatment of this disease.
ABSTRACT
ObjectiveTo study the inhibitory effect of aloe-emodin （AE） on aluminum ion （Al3+）-induced β-amyloid protein 42 （Aβ42） aggregation and its depolymerization on formed Aβ42-Al3+ aggregates in vitro， and to investigate the effect of AE on the cytotoxicity of Aβ42 aggregation in the presence of Al3+. MethodThe Aβ42 group， Aβ42+Al3+ group， Aβ42+AE group， Aβ42+Al3++AE group and the depolymerization test group were set up in the experiment. The aggregation fibrosis process， aggregation morphology， aggregation size and cytotoxicity of Aβ42 in each group were detected by thioflavin T （ThT） fluorescence assay， transmission electron microscopy （TEM）， dynamic light scattering （DLS） experiment and thiazolyl blue （MTT） cytotoxicity assay. ResultCompared with the Aβ42 group， Al3+ could promote Aβ42 aggregation， increase the fluorescence intensity of ThT by 124.48%， induce the aggregation of Aβ42 to form fiber bundles with larger particle size， and significantly reduce the cell viability of human neuroblastoma SH-SY5Y cells （P<0.01）， thus reducing the cell survival rate to 51.05%. AE not only inhibited Aβ42 aggregation， but also inhibited Al3+-induced Aβ42 aggregation in a concentration-dependent manner. Compared with the Aβ42+Al3+ group， high concentration of AE could reduce the ThT fluorescence intensity to 41.66%， and change the polypeptide aggregation pathway to form amorphous aggregates with small particle size. Besides， it significantly inhibited the cytotoxicity of Aβ42 induced by Al3+ （P<0.01）， and restored the cell survival rate to 84.87%. Further depolymerization was conducted， AE could depolymerize Aβ42-Al3+ aggregates to make the formed aggregates disappear and form some small-particle short fibers and amorphous structure aggregates with low toxicity. ConclusionAE can inhibit Aβ42 aggregation and cytotoxicity in the presence of Al3+， depolymerize the formed Aβ42-Al3+ aggregates and alleviate the cytotoxicity， thus laying the foundation for exploring the mechanism of AE in the treatment of Alzheimer's disease.