BDNF Signaling in Vascular Dementia and Its Effects on Cerebrovascular Dysfunction, Synaptic Plasticity, and Cholinergic System Abnormality

Vascular dementia (VaD) is the second most common type of dementia and is characterized by memory impairment, blood-brain barrier disruption, neuronal cell loss, glia activation, impaired synaptic plasticity, and cholinergic system abnormalities. To effectively prevent and treat VaD a good understanding of the mechanisms underlying its neuropathology is needed. Brain-derived neurotrophic factor (BDNF) is an important neurotrophic factor with multiple functions in the systemic circulation and the central nervous system and is known to regulate neuronal cell survival, synaptic formation, glia activation, and cognitive decline. Recent studies indicate that when compared with normal subjects, patients with VaD have low serum BDNF levels and that BDNF deficiency in the serum and cerebrospinal fluid is an important indicator of VaD. Here, we review current knowledge on the role of BDNF signaling in the pathology of VaD, such as cerebrovascular dysfunction, synaptic dysfunction, and cholinergic system impairment.

The neurotransmitter puzzle of Alzheimer's: Dissecting mechanisms and exploring therapeutic horizons

Alzheimer's Disease (AD) represents a complex interplay of neurological pathways and molecular mechanisms, with significant impacts on patients' lives. This review synthesizes the latest developments in AD research, focusing on both the scientific advancements and their clinical implications. We examine the role of microglia in AD, highlighting their contribution to the disease's inflammatory aspects. The cholinergic hypothesis, a cornerstone of AD research, is re-evaluated, including the role of Alpha-7 Nicotinic Acetylcholine Receptors in disease progression. This review places particular emphasis on the neurotransmission systems, exploring the therapeutic potential of GABAergic neurotransmitters and the role of NMDA inhibitors in the context of glutamatergic neurotransmission. By analyzing the interactions and implications of neurotransmitter pathways in AD, we aim to shed light on emerging therapeutic strategies. In addition to molecular insights, the review addresses the clinical and personal aspects of AD, underscoring the need for patient-centered approaches in treatment and care. The final section looks at the future directions of AD research and treatment, discussing the integration of scientific innovation with patient care. This review aims to provide a comprehensive update on AD, merging scientific insights with practical considerations, suitable for both specialists and those new to the field.

Ethanol extract of Evodia lepta Merr. ameliorates cognitive impairment through inhibiting NLRP3 inflammasome in scopolamine-treated mice

Evodia lepta Merr. (Evodia lepta) is a well-known traditional Chinese medicine, which has been widely used in herbal tea. We previously reported that the coumarin compounds from the root of Evodia lepta exhibited neuroprotective effects. However, whether Evodia lepta could inhibit NLRP3 inflammasome in dementia was still unknown. In this study, the components of the Evodia lepta extract were identified by HPLC-Q-TOF HRMS. We employed a scopolamine-treated mouse model. Evodia lepta extract (10 or 20 mg/kg) and donepezil were treated by gavage once a day for 14 consecutive days. Following the behavioral tests, oxidative stress levels were measured. Then, Western blot and immunofluorescence analysis were used to evaluate the expressions of NLRP3 inflammasome. 14 major components of the Evodia lepta extract were identified by HPLC-Q-TOF HRMS. The results of Morris water maze, object recognition task and open field test indicated that Evodia lepta extract could ameliorate cognitive impairment in scopolamine-treated mice. Evodia lepta extract improved cholinergic system. Moreover, Evodia lepta extract improved the expressions of PSD95 and BDNF. Evodia lepta extract suppressed neuronal oxidative stress and apoptosis. In addition, Evodia lepta extract inhibited NLRP3 inflammasome in the hippocampus of scopolamine-treated mice. Evodia lepta extract could protect against cognitive impairment by inhibiting NLRP3 inflammasome in scopolamine-treated mice.

The neurobiology and therapeutic potential of multi-targeting β-secretase, glycogen synthase kinase 3β and acetylcholinesterase in Alzheimer's disease

Alzheimer's Disease (AD) is the most common form of dementia, affecting almost 50 million of people around the world, characterized by a complex and age-related progressive pathology with projections to duplicate its incidence by the end of 2050. AD pathology has two major hallmarks, the amyloid beta (Aβ) peptides accumulation and tau hyperphosphorylation, alongside with several sub pathologies including neuroinflammation, oxidative stress, loss of neurogenesis and synaptic dysfunction. In recent years, extensive research pointed out several therapeutic targets which have shown promising effects on modifying the course of the disease in preclinical models of AD but with substantial failure when transposed to clinic trials, suggesting that modulating just an isolated feature of the pathology might not be sufficient to improve brain function and enhance cognition. In line with this, there is a growing consensus that an ideal disease modifying drug should address more than one feature of the pathology. Considering these evidence, β-secretase (BACE1), Glycogen synthase kinase 3β (GSK-3β) and acetylcholinesterase (AChE) has emerged as interesting therapeutic targets. BACE1 is the rate-limiting step in the Aβ production, GSK-3β is considered the main kinase responsible for Tau hyperphosphorylation, and AChE play an important role in modulating memory formation and learning. However, the effects underlying the modulation of these enzymes are not limited by its primarily functions, showing interesting effects in a wide range of impaired events secondary to AD pathology. In this sense, this review will summarize the involvement of BACE1, GSK-3β and AChE on synaptic function, neuroplasticity, neuroinflammation and oxidative stress. Additionally, we will present and discuss new perspectives on the modulation of these pathways on AD pathology and future directions on the development of drugs that concomitantly target these enzymes.

Effects of baicalein with memantine on aluminium chloride-induced neurotoxicity in Wistar rats

Alzheimer's disease is a progressive neurodegenerative condition. It is one of the most common 28 forms of dementia accounting for 60-80% of people suffering from dementia. There are very few medications that are approved for the treatment of Alzheimer's disease. Baicalein, belonging to the flavone subclass of flavonoids, has been reported to have a neuroprotective effect by reducing oxidative stress and neuroinflammation, inhibiting the AChE enzyme, and reducing amyloid protein aggregation and toxicity. Memantine is one of the most important drugs used for treating Alzheimer's disease. The purpose of this work was to study the effect of baicalein with memantine on aluminum chloride-induced neurotoxicity in Wistar rats. Aluminum chloride (100 mg/kg p.o.) was administered for 42 days in male Wistar rats to induce neurotoxicity. Baicalein alone (10 mg/kg) and a combination of baicalein (5 mg/kg and 10 mg/kg) with memantine (20 mg/kg) were administered for 42 days. Treatment of baicalein with memantine showed significant improvement in behavioral parameters. The combination reduced oxidative stress and the formation of β-Amyloid plaques and increased brain-derived neurotrophic factor (BDNF) expression. Based on findings, it can be concluded that treatment with baicalein and memantine may slow the progression of neurodegeneration in rats.

Many Paths to Alzheimer's Disease: A Unifying Hypothesis Integrating Biological, Chemical, and Physical Risk Factors

Sporadic Alzheimer's disease (AD) is a complex, multifactorial disease. We should therefore expect to find many factors involved in its causation. The known neuropathology seen at autopsy in patients dying with AD is not consistently seen in all patients with AD and is sometimes seen in patients without dementia. This suggests that patients follow different paths to AD, with different people having slightly different combinations of predisposing physical, chemical and biologic risk factors, and varying neuropathology. This review summarizes what is known of the biologic and chemical predisposing factors and features in AD. We postulate that, underlying the neuropathology of AD is a progressive failure of neurons, with advancing age or other morbidity, to rid themselves of entropy, i.e., the disordered state resulting from brain metabolism. Understanding the diverse causes of AD may allow the development of new therapies targeted at blocking the paths that lead to dementia in each subset of patients.

The Aqueous Extract of Humulus japonicus Ameliorates Cognitive Dysfunction in Alzheimer's Disease Models via Modulating the Cholinergic System

Humulus japonicus (HJ) is an herbal medicine, which has been reported as being antioxidative and anti-inflammatory. The present study aimed to investigate the effect of oral administration of HJ water extract (HJW) on cognitive function through the cholinergic system in Alzheimer's disease (AD) mouse models. Institute of Cancer Research mice injected with beta-amyloid (Aβ) (1-42) (i.c.v.) and APP/PS1 transgenic (TG) mice were orally administered with HJW at 500 mg/kg/day for 3 weeks. Aβ-injected mice and APP/PS1 TG mice showed cognitive dysfunction, which was evaluated by various behavioral tests. HJW treatment significantly attenuated memory impairments in Aβ-injected mice and APP/PS1 TG mice. Aβ injection decreased acetylcholine (ACh) concentrations and choline acetyltransferase (ChAT) activity, and increased acetylcholinesterase (AChE) activity. These cholinergic impairments were also found in APP/PS1 TG mice. HJW significantly attenuated cholinergic alterations in Aβ-injected mice and TG mice. In addition, HJW significantly decreased Aβ plaque deposition in the cerebral cortex and hippocampus of TG mice. Therefore, the present study demonstrated that HJW protected against AD-related memory impairments via enhancing the cholinergic system and inhibiting Aβ plaque deposition.

Screening of phytochemicals, toxicities, and activities of three Dillenia species

Introduction: Plants containing β-sitosterol and oleamide are important for various diseases. So, Dillenia indica, D. obovata, and D. pentagyna were investigated for phytochemicals, cytotoxicity and genotoxicity levels on peripheral blood mononuclear cells (PBMCs) and Hela cells. The protective effect of D. pentagyna extract on a HepG2 cell line was also investigated. Methods: Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) were used for phytochemical analysis. 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction (MTT) and comet assays were performed for toxicity testing and protective effects against DNA oxidative damage. Results: The major components were oleamide and β-sitosterol at 38.464-58.247% and 5.585- 6.887% with concentration and quantity of β-sitosterol at 0.2-0.37 mg/mL and 0.42-0.964 mg/g leaf. The D. indica, D. obovata, and D. pentagyna toxicities on PBMCs showed IC50 values at >430, >430, and 350 µg/mL respectively, with no significant DNA damage (P > 0.05) compared to the negative control group. All plant extracts showed toxic activity on Hela cell with IC50 values at <0.43 µg/mL and induced significant DNA damage (P < 0.05) compared to the negative control group. Conversely, the activity of the D. pentagyna extract indicated low cytotoxic activity against HepG2 (IC50>430 μg/mL), no significant (P > 0.05) DNA damage induction, significantly (P < 0.05) decreased DNA damage level, and tremendous antioxidant effect. Additionally, a combined mixture of all plants in an equal proportion revealed no IC50 value and insignificant DNA damage. Conclusion: All the studied species contained oleamide and β-sitosterol, with toxicity on Hela cells without toxicity on PBMC. The D. pentagyna species showed high antioxidant effects and no toxicity on HepG2.

The Methylglyoxal/RAGE/NOX-2 Pathway is Persistently Activated in the Hippocampus of Rats with STZ-Induced Sporadic Alzheimer's Disease

Alzheimer's disease (AD) is the leading cause of dementia in humans, with a high social and economic cost. AD is predominantly a sporadic disease, and the intracerebroventricular (ICV) administration of streptozotocin (STZ) has been widely used as an AD-like model of dementia. While the etiology of AD remains unknown, changes such as glucose metabolism and activation of receptors for advanced glycation end products (RAGE) seem to underlie its pathogenesis. We hypothesized that methylglyoxal, an endogenous toxin derived from the glycolytic pathway, could be the precursor of advanced glycated end products that activates RAGE and that, consequently, may activate membrane NADPH oxidase (NOX), contributing to the inflammatory status of the model and the disease. We administered ICV-STZ to Wistar rats and evaluated several neurochemical parameters in the hippocampus, particularly glyoxalase 1 (GLO-1) activity, which serves as an index of high levels of methylglyoxal, and the contents of RAGE and NOX-2, the most abundant brain NOX isoform. At the times evaluated (4 and 24 weeks after STZ), we observed cognitive deficit, increased beta-amyloid content, and increased tau phosphorylation. A persistent increase in GLO-1 activity was found, as well as increases in RAGE and NOX-2 contents, suggesting astroglial and microglial commitment. The increase in NOX-2 may reflect elevated microglial activity (confirmed by IBA-1 marker), which may contribute to the synaptic dysfunction and pruning described in the literature, both in this model and AD patients. Furthermore, reinforcing this possibility, we found a reduction in cholinergic communication in the hippocampus (as shown by decreased choline acetyltransferase), a reduction in BDNF, and an increase in TGF-β, the combination of which may result in synaptic deterioration.

Attenuative Effects of Fluoxetine and Triticum aestivum against Aluminum-Induced Alzheimer's Disease in Rats: The Possible Consequences on Hepatotoxicity and Nephrotoxicity

BACKGROUND

Alzheimer's disease (AD) is a chronic neurological illness that causes considerable cognitive impairment. Hepatic and renal dysfunction may worsen AD by disrupting β-amyloid homeostasis at the periphery and by causing metabolic dysfunction. Wheatgrass (Triticum aestivum) has been shown to have antioxidant and anti-inflammatory properties. This work aims to study the effect of aluminum on neuronal cells, its consequences on the liver and kidneys, and the possible role of fluoxetine and wheatgrass juice in attenuating these pathological conditions.

METHOD

Rats were divided into five groups. Control, AD (AlCl₃), Fluoxetine (Fluoxetine and AlCl₃), Wheatgrass (Wheatgrass and AlCl₃), and combination group (fluoxetine, wheatgrass, and AlCl₃). All groups were assigned daily to different treatments for five weeks.

CONCLUSIONS

AlCl₃ elevated liver and kidney enzymes, over-production of oxidative stress, and inflammatory markers. Besides, accumulation of tau protein and Aβ, the elevation of ACHE and GSK-3β, down-regulation of BDNF, and β-catenin expression in the brain. Histopathological examinations of the liver, kidney, and brain confirmed this toxicity, while treating AD groups with fluoxetine, wheatgrass, or a combination alleviates toxic insults.

CONCLUSION

Fluoxetine and wheatgrass combination demonstrated a more significant neuroprotective impact in treating AD than fluoxetine alone and has protective effects on liver and kidney tissues.

Oleamide in Ipomoea and Dillenia Species and Inflammatory Activity Investigated through Ion Channel Inhibition

BACKGROUND

Oleamide is an essential substance for human health. So, the plants with high oleamide content are great sources for health care products.

OBJECTIVE

This study is conducted to investigate the quality of oleamide in plants and test the bioactivity in the selected two studied species.

METHODS

The three Ipomoea and five Dillenia species including Ipomoea alba, Ipomoea aquatica and Ipomoea pes-caprae, and Dillenia indica, Dillenia obovata, Dillenia ovata, Dillenia parviflora and Dillenia pentagyna were investigated for the quantity of oleamide by high-performance liquid chromatography. The biological activity test was conducted on the powder formulation of the chosen plants, Dillenia ovata and Dillenia parviflora at a ratio of 30:70, for anti-inflammatory activity ex vivo on a panel of molecular targets through ion channel inhibition including voltage-gated sodium channel, voltage-gated potassium channel, and the cardiac ion as human ether-a-go-go related gene.

RESULTS

The results showed that the leaf extracts of I. aquatica and D. ovata gave the highest and subsequent oleamide quantity i.e. 7.52 and 5.17 mg/g, respectively. Out of the Dillenia formulation which contained various compounds, oleamide showed the highest percentages of inhibition at 8.0-20.0%, and 6.2-14.2% in voltage-gated sodium channel, and voltage-gated potassium channel which had slightly lower values than the oleamide standard, and no effect as 0.0% value inhibition in the cardiac ion channel.

CONCLUSION

The Dillenia formulation exhibits anti-inflammatory activity without affecting the heart. Accordingly, the three studied Ipomoea and three studied Dillenia species may be used for the same activity as a single component or formulation with effective solvent for disease treatments.

Formulations for effective detoxification derived fromthree medicinalplants: Thunbergia laurifolia,Clerodendrum disparifoliumand Rotheca serrata

BACKGROUND

Based on the long history of medicinal use of Thunbergia laurifolia, Clerodendrum disparifolium and Rotheca serrata, the extract formulations of these species: T. laurifolia and C. disparifolium; T. laurifolia and R. serrata;and T. laurifolia, C. disparifolium and R. serrata, called formulas 1, 2 and 3, were created for detoxification testing to take more advantage of eachspecies.

OBJECTIVE

To estimate the detoxifying effects of studiedextract formulations on human cell and tissue culture as a preclinical trial.

METHODS

Themajor phytochemicals were derived by GC-MS. Thedetoxification efficacy of these formulations in cellsand DNA levelsby MTT and cometassays in toxic PBMCs (incubated with rice whisky or bathroom cleaner).

RESULTS

The phytochemical constituents were detected at 23.48% phytol and 43.03% oleamide in T. laurifolia; 12.88% oleamide, 20.93% 9,12,15-octadecatrien, 25.52% squalene, 22.19% butylated hydroxy toluene and 15.36% vitamin E in C. disparifolium; and 30.41% phytol, 32.78% oleamide, and12.20%, 9,12,15-octadecatrien-1-ol in R. serrata.The toxic cells treated with the plant formulas 1, 2 and 3 showed no IC50 values,but formulas 1 and 2 displayed higher efficaciesthandid formula 3. The comet assay indicated that the experiments (the treatment on toxic cells with the plant formulas) induced significant (p<0.05) DNA damage compared to the negative control due to poisoning occurring before administration of the plant formulas. The OTM of the controls was significantly (p<0.05) longer than the experimental samplesshowing significantly reduce toxicityof the created formulations.

CONCLUSION

The formulas showed high detoxification efficacies and the formulations 1 and 2resulted inhigher levels of detoxification thanthe formulation3, especially immediate treatment after receiving toxic substances.

Alterations of GABA B receptors in the APP/PS1 mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the progressive decline of memory and cognitive function. The disease is characterized by the presence of amyloid plaques, tau tangles, altered inflammatory signaling, and alterations in numerous neurotransmitter signaling systems, including γ-aminobutyric acid (GABA). Given the extensive role of GABA in regulating neuronal activity, a careful investigation of GABA-related changes is needed. Further, given persistent inflammation has been demonstrated to drive AD pathology, the presence of GABA B receptor expressed on glia that serve a role regulation of the immune response adds to potential implications of altered GABA in AD. There has not previously been a systematic evaluation of GABA-related changes in an amyloid model of AD that specifically focuses on examining changes in GABA B receptors. In the present study, we examined alterations in several GABA-specific targets in the APP/PS1 mouse model at different ages. In the 4-month-old cohort, no significant deficits in spatial learning and memory or alterations in any of the GABAergic targets were observed compared with wild-type controls. However, we identified significant alterations in several GABA-related targets in the 6-month-old cohort that exhibited spatial learning deficits that include changes in glutamic acid decarboxylase 65, GABA transporter type 3, and GABA B receptors protein and mRNA levels. This was the same cohort at which learning and memory deficits and significant amyloid pathology was observed. Overall, our study provides evidence of altered GABAergic signaling in an amyloid model of AD at a time point consistent with AD-related deficits.

QTC-4-MeOBnE Rescues Scopolamine-Induced Memory Deficits in Mice by Targeting Oxidative Stress, Neuronal Plasticity, and Apoptosis

Cognitive decline and memory impairment induced by disruption of cholinergic neurons and oxidative brain damage are among the earliest pathological hallmark signatures of Alzheimer's disease. Scopolamine is a postsynaptic muscarinic receptor blocker which causes impairment of cholinergic transmission resulting in cognitive deficits. Herein we investigated the effect of QTC-4-MeOBnE (1-(7-chloroquinolin-4-yl)-N-(4-methoxybenzyl)-5-methyl-1H-1,2,3-triazole-4-carboxamide) on memory impairments in mice chronically treated with scopolamine and the molecular mechanisms involved. Administration of scopolamine (1 mg/kg) for 15 days resulted in significant impairments in working and short-term memory in mice, as assessed by the novel object recognition and the Y-maze paradigms. However, both deficits were prevented if mice receiving the scopolamine were also treated with QTC-4-MeOBnE. This effect was associated with an increase in antioxidant enzymes (superoxide dismutase and catalase), a reduction in lipid peroxidation, and an increase in Nrf2 expression. Moreover, brains from QTC-4-MeOBnE treated mice had a significant decrease in acetylcholinesterase activity and glycogen synthase kinase-3β levels but an increase in brain-derived neurotrophic factor and Bcl-2 expression levels. Taken together our findings demonstrate that the beneficial effect of QTC-4-MeOBnE in a mouse model of scopolamine-induced memory impairment is mediated via the involvement of different molecular pathways including oxidative stress, neuroplasticity, neuronal vulnerability, and apoptosis. Our study provides further evidence on the promising therapeutic potential of QTC-4-MeOBnE as a multifactorial disease modifying drug in AD and related dementing disorders.

Is Blood Brain-Derived Neurotrophic Factor a Useful Biomarker to Monitor Mild Cognitive Impairment Patients?

Availability of reliable prognostic biomarkers that are also able to monitor preventive/therapeutic interventions in patients with mild cognitive impairment (MCI) is crucial. Cerebral brain-derived neurotrophic factor (BDNF) alterations were evidenced in Alzheimer's disease, but the value of blood BDNF in MCI is unclear, especially because of the incomplete/incorrect management of the numerous confounding factors unrelated to the disease. This study, applying a multidisciplinary methodological approach, aimed at clarifying whether blood BDNF can really mirror the cognitive symptoms of MCI, thus supporting the evaluation of clinical protocols' effectiveness as well as the definition of the conversion rate to dementia. Healthy elderly subjects (HE) and MCI patients were assessed for sociodemographic, neuropsychological, pharmacological, and lifestyle data, and plasma BDNF was measured (baseline); then, in the MCI cohort, the biomarker was tested in a comprehensive cognitive stimulation intervention (CS) as well as in a 2-year follow-up period. Plasma BDNF, cleansed from all the interfering factors, (1) did not discriminate HE and MCI patients; (2) in MCI patients reflected mood, social engagement, and subjective memory complaints but not cognition; (3) changed due to CS, although with no correlations to cognitive performances; and (4) predicted no functional deterioration. Our data indicate that the possible biased use of plasma BDNF in MCI is critically risky.

Cross-talk between guanidinoacetate neurotoxicity, memory and possible neuroprotective role of creatine

Guanidinoacetate Methyltransferase deficiency is an inborn error of metabolism that results in decreased creatine and increased guanidinoacetate (GAA) levels. Patients present neurological symptoms whose mechanisms are unclear. We investigated the effects of an intrastriatal administration of 10 μM of GAA (0.02 nmol/striatum) on energy metabolism, redox state, inflammation, glutamate homeostasis, and activities/immunocontents of acetylcholinesterase and Na⁺,K⁺-ATPase, as well as on memory acquisition. The neuroprotective role of creatine was also investigated. Male Wistar rats were pretreated with creatine (50 mg/kg) or saline for 7 days underwenting stereotactic surgery. Forty-eight hours after surgery, the animals (then sixty-days-old) were divided into groups: Control, GAA, GAA + Creatine, and Creatine. Experiments were performed 30 min after intrastriatal infusion. GAA decreased SDH, complexes II and IV activities, and ATP levels, but had no effect on mitochondrial mass/membrane potential. Creatine totally prevented SDH and complex II, and partially prevented COX and ATP alterations. GAA increased dichlorofluorescein levels and decreased superoxide dismutase and catalase activities. Creatine only prevented catalase and dichlorofluorescein alterations. GAA increased cytokines, nitrites levels and acetylcholinesterase activity, but not its immunocontent. Creatine prevented such effects, except nitrite levels. GAA decreased glutamate uptake, but had no effect on the immunocontent of its transporters. GAA decreased Na⁺,K⁺-ATPase activity and increased the immunocontent of its α3 subunit. The performance on the novel object recognition task was also impaired. Creatine partially prevented the changes in glutamate uptake and Na⁺,K⁺-ATPase activity, and completely prevented the memory impairment. This study helps to elucidate the protective effects of creatine against the damage caused by GAA.

Co-Administration of TiO2 Nanowired Mesenchymal Stem Cells with Cerebrolysin Potentiates Neprilysin Level and Reduces Brain Pathology in Alzheimer's Disease

Neprilysin (NPL), the rate-limiting enzyme for amyloid beta peptide (AβP), appears to play a crucial role in the pathogenesis of Alzheimer's disease (AD). Since mesenchymal stem cells (MSCs) and/or cerebrolysin (CBL, a combination of neurotrophic factors and active peptide fragments) have neuroprotective effects in various CNS disorders, we examined nanowired delivery of MSCs and CBL on NPL content and brain pathology in AD using a rat model. AD-like symptoms were produced by intraventricular (i.c.v.) administration of AβP (1-40) in the left lateral ventricle (250 ng/10 μl, once daily) for 4 weeks. After 30 days, the rats were examined for NPL and AβP concentrations in the brain and related pathology. Co-administration of TiO2-nanowired MSCs (10⁶ cells) with 2.5 ml/kg CBL (i.v.) once daily for 1 week after 2 weeks of AβP infusion significantly increased the NPL in the hippocampus (400 pg/g) from the untreated control group (120 pg/g; control 420 ± 8 pg/g brain) along with a significant decrease in the AβP deposition (45 pg/g from untreated control 75 pg/g; saline control 40 ± 4 pg/g). Interestingly, these changes were much less evident when the MSCs or CBL treatment was given alone. Neuronal damages, gliosis, and myelin vesiculation were also markedly reduced by the combined treatment of TiO2, MSCs, and CBL in AD. These observations are the first to show that co-administration of TiO2-nanowired CBL and MSCs has superior neuroprotective effects in AD probably due to increasing the brain NPL level effectively, not reported earlier.

Peripheral Blood Brain-Derived Neurotrophic Factor as a Biomarker of Alzheimer's Disease: Are There Methodological Biases?

Mounting evidence that alterations in brain-derived neurotrophic factor (BDNF) levels and signaling may be involved in the etiopathogenesis of Alzheimer's disease (AD) has suggested that its blood levels could be used as a biomarker of the disease. However, higher, lower, or unchanged circulating BDNF levels have all been described in AD patients compared to healthy controls. Although the reasons for such different findings are unclear, methodological issues are likely to be involved. The heterogeneity of participant recruitment criteria and the lack of control of variables that influence circulating BDNF levels regardless of dementia (depressive symptoms, medications, lifestyle, lack of overlap between serum and plasma, and experimental aspects) are likely to bias result and prevent study comparability. The present work reviews a broad panel of factors, whose close control could help reduce the inconsistency of study findings, and offers practical advice on their management. Research directed at elucidating the weight of each of these variables and at standardizing analytical methodologies is urgently needed.

Clinical and Environmental Correlates of Serum BDNF: A Descriptive Study with Plausible Implications for AD Research

BACKGROUND

Brain derived neurotrophic factor (BDNF) may play a central role in the pathogenesis of Alzheimer's disease (AD) through neurotrophic effects on basal cholinergic neurons. Reduced serum levels of BDND are observed among AD patients and may predict AD risk. Nevertheless, knowledge about factors associated with its levels in blood is lacking.

OBJECTIVE

To identify clinical and demographic correlates of serum BDNF levels.

METHODS

BDNF was measured from serum collected between 1992-1996 and 1998-2001 in participants from the Original and Offspring cohorts of the Framingham Study, respectively. A cross-sectional analysis was done to evaluate the relationship between clinical measures and BDNF levels using standard linear regression and stepwise models. Analyses were conducted in the total sample and separately in each cohort, and were adjusted for age and sex.

RESULTS

BDNF was measured in 3,689 participants (mean age 65 years, 56% women; 82% Offspring). Cigarette smoking and high total cholesterol were associated with elevated BDNF levels, and history of atrial fibrillation was associated with decreased levels. Elevated BDNF levels were related to greater physical activity and lower Tumor Necrosis Factor-α levels in Offspring. Stepwise models also revealed associations with statin use, alcohol consumption and Apolipoprotein Eε4 genotype.

CONCLUSION

Serum BDNF correlates with various metabolic, inflammatory and life-style measures which in turn have been linked with risk of AD. Future studies of serum BDNF should adjust for these correlates and are needed to further explore the underlying interplay between BDNF and other factors in the pathophysiology of cognitive impairment and AD.

The cholinergic anti-inflammatory pathway: An innovative treatment strategy for neurological diseases

Acetylcholine (ACh), as a classical neurotransmitter, regulates the neuronal network in response to internal and external stimuli. In recent decades, the biology of ACh has been endowed with unparalleled new insights, especially with respect to cholinergic anti-inflammatory properties in non-neuronal cells. In fact, a mechanism frequently referred to as the "cholinergic anti-inflammatory pathway" has been termed to describe interactions between the central nervous system (CNS) and the immune system via vagus nerve. As well documented, immune cells express choline acetyltransferase, a direct synthetase for ACh, and other corresponding cholinergic components. Alternatively, the ACh released from immune cells or cholinergic neurons modulates immune function in an autocrine/paracrine manner by acting on its receptors. Moreover, muscarinic or nicotinic ACh receptors on various immune cells and CNS glial cells administer the work of their respective agonists, causing functional and biochemical changes. In this review, we focus on the anti-inflammatory benefits of non-neuronal and neuronal ACh as a means of providing new insights into treating inflammation-related neurological diseases, as exemplified by those described herein.