linoleic-acid and Alzheimer-Disease

The present study aimed to investigate the protective effect and underlying mechanism of Platycladi Semen oil(SP) on Aβ_(25-35)-induced brain injury in mice to provide a theoretical basis for the clinical treatment of Alzheimer's disease(AD). Male Kunming(KM) mice were randomly divided into a control group, a model group(brain injection of Aβ_(25-35), 200 μmol·L~(-1), 0.15 μL·g~(-1)), a positive drug group(donepezil, 10 mg·kg~(-1)), and low-and high-dose SP groups(0.5 and 1 mL·kg~(-1)). Learning and memory ability, neuronal damage, levels of Aβ_(1-42)/Aβ_(1-40), p-Tau, related indicators of apoptosis and oxidative stress, and immune cells, and protein and mRNA expression related to the sphingosine kinase 1(SPHK1)/sphingosine-1-phosphate(S1P)/sphingosine-1-phosphate receptor 5(S1PR5) signaling pathway of mice in each group were determined. In addition, compounds in SP were analyzed by gas chromatography-mass spectrometry(GC-MS). The mechanism of SP against AD was investigated by network pharmacology, 16S rDNA gene sequencing for gut microbiota(GM), and molecular docking techniques. The results showed that SP could improve the learning and memory function of Aβ_(25-35)-induced mice, reduce hippocampal neuronal damage, decrease the levels of Aβ_(1-42)/Aβ_(1-40), p-Tau, and indicators related to apoptosis and oxidative stress in the brain, and maintain the homeostasis of immune cells and GM. Network pharmacology and sequencing analysis for GM showed that the therapeutic effect of SP on AD was associated with the sphingolipid signaling pathway. Meanwhile,(Z,Z,Z)-9,12,15-octadecatrienoic acid and(Z,Z)-9,12-octadecadienoic acid, the components with the highest content in SP, showed good binding activity to SPHK1 and S1PR5. Therefore, it is inferred that SP exerts anti-apoptosis and antioxidant effects by regulating GM and inhibiting SPHK1/S1P/S1PR5 pathway, thereby improving brain injury induced by Aβ_(25-35) in mice. Moreover,(Z,Z,Z)-9,12,15-octadecatrienoic acid and(Z,Z)-9,12-octadecadienoic acid may be the material basis for the anti-AD effect of SP.

Topics: Alzheimer Disease; Animals; Brain Injuries; Gastrointestinal Microbiome; Linoleic Acid; Male; Mice; Molecular Docking Simulation; Network Pharmacology; Semen

With the steadily increasing prevalence of Alzheimer's disease (AD) and great difficulties encountered for AD drug development presently, much interest has been devoted to identifying modifiable risk factors to lower the risk of AD, while the causal associations between risk factors and AD remain inconclusive. The present study conducted a comprehensive evaluation of the causal associations between risk factors and AD development by taking the recent advancements of Mendelian randomization (MR). Inverse variance weighted (IVW), MR-Egger, weighted median, and weighted mode were used for complementary calculation. A total of 45 risk factors and corresponding studies were covered in the study. This two-sample MR (2SMR) analysis provided a suggestive association between genetically predicted higher years of schooling and reduced risks of AD, and each standard deviation (3.71 years) increased in years of schooling was associated with a 41% reduction in the risk of AD (IVW, OR: 0.59, 95% CI: 0.45-0.77). At the same time, it was genetically predicted that urate might be a risk factor in AD, and it was found that each standard deviation increase in urate levels (1.33 mg/dL) was associated with a 0.09-fold increase in the risk of AD (IVW, OR: 1.09, 95% CI: 1.01-1.18). To summarize, the 2SMR analysis indicated a suggestive association between genetically predicted higher years of schooling and reduced risks of AD, and between genetically predicted higher urate levels and increased risks of AD. The findings provide useful clues to help combat AD and warrants future studies.

Topics: Alzheimer Disease; Body Height; Copper; Educational Status; Genome-Wide Association Study; Hippocampus; Humans; Linoleic Acid; Mendelian Randomization Analysis; Organ Size; Polymorphism, Single Nucleotide; Risk Factors; Uric Acid

Polyunsaturated fatty acids (PUFAs) are closely related to various physiological conditions. In several age-related diseases including Alzheimer's disease (AD) altered PUFAs metabolism has been reported. However, the mechanism behind PUFAs impairment and AD developpement remains unclear. In humans, PUFAs biosynthesis requires delta-5 desaturase (D5D), delta-6 desaturase (D6D) and elongase 2 activities; which are encoded by fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2), and elongation of very-long-chain fatty acids-like 2 (ELOVL2) genes, respectively. In the present work, we aim to assess whether genetic variants in FADS1, FADS2 and ELOVL2 genes influence plasma and erythrocyte PUFA composition and AD risk. A case-control study was carried out in 113 AD patients and 161 healthy controls.Rs174556, rs174617, and rs3756963 of FADS1, FADS2, and ELOVL2 genes, respectively were genotyped using PCR-RFLP. PUFA levels were quantified using Gas Chromatography. Genotype distributions of rs174556 (FADS1) and rs3756963 (ELOVL2) were different between case and control groups. The genotype TT of rs174556 and rs3756963 single nucleotide polymorphism (SNP) increases significantly the risk of AD in our population. PUFA analysis showed higher plasma and erythrocyte arachidonic acid (AA) level in patients with AD, whereas only plasma docosahexaenoic acid (DHA) was significantly decreased in AD patients. The indexes AA/Dihomo-gamma-linolenic acid (DGLA) and C24:4n-6/Adrenic acid (AdA) were both higher in the AD group. Interestingly, patients with TT genotype of rs174556 presented higher AA level and AA/DGLA index in both plasma and erythrocyte. In addition, higher AA and AA/DGLA index were observed in erythrocyte of TT genotype ofrs3756963 carrier's patients. Along with, positive correlation between AA/DGLA index, age or Gamma-linolenic acid (GLA)/ Linoleic acid (LA) index was seen in erythrocyte and /or plasma of AD patients. After adjustment for confounding factors, the genotype TT of rs174556, erythrocyte AA and AA/DGLA index were found to be predictive risk factors for AD while plasma DHA was found associated with lower AD risk. Both rs174556 and rs3756963 influence AD risk in the Tunisian population and they are likely associated with high AA level. The combination of the two variants increases further the susceptibility to AD. We suggest that FADS1 and ELOVL2 variants could likely regulate the efficiency of AA biosynthesis which could be at the origin

Topics: 8,11,14-Eicosatrienoic Acid; Alleles; Alzheimer Disease; Arachidonic Acid; Case-Control Studies; Chromatography, Gas; Delta-5 Fatty Acid Desaturase; Docosahexaenoic Acids; Erythrocytes; Fatty Acid Desaturases; Fatty Acid Elongases; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Genotype; Humans; Linoleic Acid; Polymorphism, Single Nucleotide; Regression Analysis; Risk Factors; Tunisia

Alzheimer's disease (AD) is a neurodegenerative disorder without a known cure or effective treatment. Research has identified several modifiable risk factors and suggested preventative measures to reduce the risk of developing AD, including alterations in diet. Polyunsaturated fatty acids (PUFAs) have been shown to regulate inflammatory responses in the central nervous system (CNS), the main site of inflammation in AD. In the CNS, microglia are immune cells responsible for the maintenance of homeostasis. However, in AD, microglia can become adversely activated, causing them to release increased levels of cytotoxins and inflammatory mediators, including nitric oxide (NO) and monocyte-chemoattractant protein (MCP)-1. We assessed the effects of two PUFAs, α-linolenic acid (ALA) and linoleic acid (LA), on select microglial immune functions, since the effects of these dietary fatty acids on neuroimmune responses are not well characterized. In BV-2 mouse microglia activated with lipopolysaccharide (LPS), exposure to LA reduced NO secretion and inducible nitric oxide synthase (iNOS) levels, whereas exposure to ALA reduced NO without a corresponding reduction of iNOS. Neither ALA nor LA altered MCP-1 levels or cytotoxins released by THP-1 human microglia-like cells stimulated with a combination of LPS and interferon (IFN)-γ. Specific receptor antagonists were used to demonstrate that the inhibitory effect of LA on NO secretion did not depend on the free fatty acid receptor (FFAR) 1 or FFAR4. Furthermore, gas chromatography with a flame ionization detector (GC-FID) revealed that exposure to LA or ALA did not alter the fatty acid composition of BV-2 microglia. Our data indicate that regulation of select microglial immune functions by ALA and LA could be one of the mechanisms underlying the observed link between certain dietary patterns and AD, such as reduced risk of cognitive decline and dementia associated with the Mediterranean diet.

Topics: alpha-Linolenic Acid; Alzheimer Disease; Animals; Cell Line; Cytokines; Dietary Fats; Humans; Inflammation Mediators; Linoleic Acid; Membrane Lipids; Mice; Microglia; Nitric Oxide; Nitric Oxide Synthase Type II; Receptors, G-Protein-Coupled; THP-1 Cells

Epidemiological studies have suggested a positive correlation between saturated fat intake and the risk for developing Alzheimer's disease (AD). While diets-enriched in the saturated free fatty acid (sFFA) palmitate has been shown to induce cognitive dysfunction and AD-like pathology, polyunsaturated fatty acids (PUFA) such as linoleate have been suggested to protect against AD in mouse models. However, the underlying cellular and molecular mechanisms that mediate the deleterious effects of palmitate or the protective effects of linoleate remain to be characterized. We fed 9-month-old cohorts of triple transgenic AD mice (3xTg-AD) and their-matched controls with a palmitate-enriched/linoleate-deficient diet for three months and determined the impact of the diet on oxidative stress, Bace1 promoter transactivation status, and amyloid-β (Aβ) burden. The palmitate-enriched/linoleate-deficient diet causes a profound increase in oxidative stress burden characterized by significant oxidative damage to lipids, proteins, and nucleic acids concomitant with deficits in the endogenous antioxidant defense capacity in the hippocampi of 3xTg-AD mice. These effects were also associated with increased NF-κB transcriptional activity resulting in NF-κB-mediated transactivation of the Bace1 promoter that culminated in higher BACE1 expression and activity, and Aβ production. Our study unveils a novel mechanism by which a diet enriched in the sFFA palmitate and deficient in the PUFA linoleate exacerbates AD-like pathology involving signaling cross-talk between oxidative stress and NF-κB activation as a critical underlying factor in upregulating BACE1 activity and increasing Aβ burden.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Antioxidants; Disease Models, Animal; Food, Fortified; Hippocampus; Linoleic Acid; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Oxidative Stress; Palmitates; Peptide Fragments

In our ongoing research to find therapeutic compounds for Alzheimer's disease (AD) from natural resources, the inhibitory activity of the BACE1 enzyme by Tenebrio molitor larvae and its major compounds were evaluated. The T. molitor larvae extract and its fractions exhibited strong BACE1 suppression. The major components of hexane fraction possessing both high yield and strong BACE1 inhibition were determined by thin layer chromatography, gas chromatography, and nuclear magnetic resonance analysis. A remarkable composition of unsaturated long chain fatty acids, including oleic acid and linoleic acid, were identified. Oleic acid, in particular, noncompetitively attenuated BACE1 activity with a half-maximal inhibitory concentration (IC₅₀) value of 61.31 μM and Ki value of 34.3 μM. Furthermore, the fatty acids were stably interacted with BACE1 at different allosteric sites of the enzyme bound with the OH of CYS319 and the NH₃ of TYR320 for oleic acid and with the C=O group of GLN304 for linoleic acid. Here, we first revealed novel pharmacophore features of oleic acids and linoleic acid to BACE1 by in silico docking studies. The present findings would clearly suggest potential guidelines for designing novel BACE1 selective inhibitors.

Topics: Alzheimer Disease; Amyloid Precursor Protein Secretases; Animals; Aspartic Acid Endopeptidases; Enzyme Inhibitors; Humans; Kinetics; Larva; Linoleic Acid; Molecular Docking Simulation; Oleic Acid; Tenebrio

Identification of molecular mechanisms underlying early stage Alzheimer's disease (AD) is important for the development of new therapies against and diagnosis of AD. In this study, nontargeted metabonomics of TASTPM transgenic AD mice was performed. The metabolic profiles of both brain and plasma of TASTPM mice were characterized using gas chromatography-mass spectrometry and compared to those of wild-type C57BL/6J mice. TASTPM mice were metabolically distinct compared to wild-type mice (Q2Y=0.587 and 0.766 for PLS-DA models derived from brain and plasma, respectively). A number of metabolites were found to be perturbed in TASTPM mice in both brain (D-fructose, L-valine, L-serine, L-threonine, zymosterol) and plasma (D-glucose, D-galactose, linoleic acid, arachidonic acid, palmitic acid and D-gluconic acid). In addition, enzyme immunoassay confirmed that selected endogenous steroids were significantly perturbed in brain (androstenedione and 17-OH-progesterone) and plasma (cortisol and testosterone) of TASTPM mice. Ingenuity pathway analysis revealed that perturbations related to amino acid metabolism (brain), steroid biosynthesis (brain), linoleic acid metabolism (plasma) and energy metabolism (plasma) accounted for the differentiation of TASTPM and wild-type mice. Our results provided insights on the pathogenesis of APP-induced AD and reinforced the role of TASTPM in drug and biomarker development.

Topics: Alzheimer Disease; Amino Acids; Animals; Biomarkers; Brain; Carbohydrate Metabolism; Disease Models, Animal; Energy Metabolism; Gas Chromatography-Mass Spectrometry; Gluconates; Glucose; Hydrocortisone; Immunoenzyme Techniques; Linoleic Acid; Male; Metabolome; Metabolomics; Mice; Mice, Inbred C57BL; Mice, Transgenic; Progesterone

Several studies have shown the protective and/or deleterious effects of dietary enrichment of single fatty acids (FAs) in several animal and cell-culture models of Alzheimer's disease (AD). However, potential interactions among dietary fatty acids are traditionally ignored. None of these studies has examined and compared the differential effects of FAs in combination, as well as alone, for their effects on amyloid β production or AD. Here we investigated the effects of omega-9 (oleic acid) and omega-6 (linoleic and arachidonic acids) fatty acids, either alone or combined, on Aβ production by APP-695 and SP-C99 transfected COS-7 cells. Overall, our results are the first to demonstrate that mixtures of FAs alter the production of Aβ40 and Aβ42 peptides and consequently the Aβ40:42 ratio differently from individual FAs. Here we show that the effects of a single lipid on Aβ production are not attributed to that single FA alone. Rather, the overall lipid composition influences the specificity and level of the regulated intramembranous proteolysis of APP by the γ-secretase complex. Our results reinforce the importance of studying composite lipids/nutrients rather than single lipids or nutrients.

Topics: Alzheimer Disease; Amyloid; Amyloid beta-Peptides; Animals; Arachidonic Acid; Cells, Cultured; Chlorocebus aethiops; COS Cells; Fatty Acids; Linoleic Acid; Oleic Acid; Peptide Fragments

Prolyl endopeptidase (PEP, EC 3.4.21.26) is widely distributed in various organs, particularly in the brains of amnestic patients. Evaluation of PEP levels in postmortem brains of Alzheimer's disease patients revealed significant increases in PEP activity, suggesting that a specific PEP inhibitor can be a good candidate for an antiamnestic drug. In this study, mono- and polyunsaturated fatty acids were investigated to determine their role as PEP inhibitors. Oleic, linoleic, and arachidonic acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) showed PEP inhibitory activities (IC50 values of 23.6 +/- 0.4, 43.8 +/- 1.8, 53.4 +/- 1.2, 99.4 +/- 1.2, and 46.2 +/- 1.0 microM, respectively), indicating that they were effective PEP inhibitors, with inhibition constant (Ki) values of 26.7 +/- 0.3, 51.0 +/- 0.7, 91.3 +/- 3.1, 247.5 +/- 2.6, and 89.0 +/- 2.3 microM, respectively. Oleic acid showed the highest PEP inhibitory activity. Dixon plots of PEP inhibition showed oleic, linoleic, and arachidonic acids, EPA, and DHA are noncompetitive inhibitors; despite higher IC50 values of these unsaturated fatty acids than strong natural inhibitors, they may have potential use in preventing memory loss.

Topics: Alzheimer Disease; Arachidonic Acid; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Humans; Linoleic Acid; Oleic Acid; Prolyl Oligopeptidases; Protease Inhibitors; Serine Endopeptidases

This work investigated the controlled release of an antibiotic drug, doxycycline HCl, from its solution/suspension in an organic solvent in a reservoir through a porous membrane employing aqueous-organic partitioning with or without a mouse skin to simulate a skin patch. The reservoir contained the agent in solution in the solvent 1-octanol or its dispersion/solution in the solvent mineral oil with or without an enhancer. The porous membranes employed with water-in-pores were hydrophobic Celgard 2400 of polypropylene and hydrophilized polyvinylidene fluoride (PVDF). Conventional Franz diffusion cells as well as a skin patch were used. The transport rates of the agent observed through both Celgard and PVDF membranes could be successfully described by Fickian diffusion through the water-filled pores when the appropriate organic-aqueous partition coefficient was incorporated. The light mineral oil-based system yielded much higher permeability due to the much lower organic-aqueous partition coefficient of the antibiotic in light mineral oil. The optimized skin patch systems yielded drug flux and permeability values similar to their relevant membrane systems. The addition of a mouse skin beneath the patch drastically reduced the drug transfer rate. Among a number of enhancers used to correct this deficiency, linoleic acid at 10% level in the reservoir solution was found to yield a flux of 2.7 +/- 0.5 microg/cm(2) h and a permeability of 2.7e - 04 +/- 5.0e - 05 cm/h. These values are higher than the values available in literature obtained with full thickness human cadaver skin.

Topics: Alzheimer Disease; Animals; Anti-Bacterial Agents; Chemical Phenomena; Chemistry, Physical; Chromatography, High Pressure Liquid; Delayed-Action Preparations; Diffusion; Doxycycline; Drug Delivery Systems; In Vitro Techniques; Linoleic Acid; Male; Membranes, Artificial; Mice; Mice, Hairless; Mineral Oil; Octanols; Permeability; Polypropylenes; Skin Absorption; Solutions

Amyloid-beta (Abeta) peptide, a major constituent of senile plaques and a hallmark of Alzheimer's disease (AD), is normally secreted by neurons and can be found in low concentrations in cerebrospinal fluid (CSF) and plasma, where it is associated with lipoproteins. However, the physiological role of Abeta secretion remains unknown. Here we show that at the concentrations measured in biological fluids (0.1-1.0 nM), Abeta(1-40) strongly inhibits autooxidation of CSF lipoproteins and plasma low density lipoprotein (LDL). At higher concentrations of the peptide its antioxidant action was abolished. Abeta(1-40) also inhibited copper-catalyzed LDL oxidation when added in molar excess of copper, but did not influence oxidation induced by an azo-initiator. Other Abeta peptides also possessed antioxidant activity in the order Abeta(1-40) > Abeta(1-42) > Abeta(25-35), whereas Abeta(35-25) was inactive. These data suggest that Abeta(1-40) may act as a physiological antioxidant in CSF and plasma lipoproteins, functioning by chelating transition metal ions.

Topics: Adult; Alzheimer Disease; Amyloid beta-Peptides; Antioxidants; Cholesterol; Copper; Humans; Hydrogen Peroxide; Kinetics; Linoleic Acid; Lipid Peroxidation; Lipoproteins; Lipoproteins, LDL; Oxidation-Reduction; Peptide Fragments

Fatty acids of plasma lipids, red cells and platelets were analyzed from 38 demented patients (age 53-88 years), comprising 11 patients with Alzheimer's disease (AD), 19 with multi-infarct dementia (MID) and 8 with probable vascular dementia (PVD). The mean age, body mass index, duration of dementia and content of triglycerides, total cholesterol and HDL-cholesterol in plasma were similar in AD and MID. The patients with PVD were older. As compared to AD, in MID and PVD the linoleic acid (LA) and other n-6 and n-3 polyunsaturated fatty acids (PUFA) were significantly lower in red cells and tended to be lower also in serum triglycerides, cholesterol esters (CHE) and phospholipids (PL), and platelets. The LA content of red cells was significantly correlated with that of serum CHE and PL, and n-6 PUFA (including arachidonic acid) of red cells. The low LA content of red cells was associated with old age, coronary heart disease and heart failure, but not with the severity of dementia.

Topics: Aged; Aged, 80 and over; Aging; Alzheimer Disease; Blood Platelets; Cerebral Infarction; Dementia; Erythrocytes; Fatty Acids; Female; Humans; Linoleic Acid; Linoleic Acids; Lipids; Male; Middle Aged