High-linoleate and high-alpha-linolenate diets affect learning ability and natural behavior in SAMR1 mice

Microalgal polyunsaturated fatty acids: Hotspots and production techniques

Algae play a crucial role in the earth’s primary productivity by producing not only oxygen but also a variety of high-value nutrients. One such nutrient is polyunsaturated fatty acids (PUFAs), which are accumulated in many algae and can be consumed by animals through the food chain and eventually by humans. Omega-3 and omega-6 PUFAs are essential nutrients for human and animal health. However, compared with plants and aquatic sourced PUFA, the production of PUFA-rich oil from microalgae is still in the early stages of exploration. This study has collected recent reports on algae-based PUFA production and analyzed related research hotspots and directions, including algae cultivation, lipids extraction, lipids purification, and PUFA enrichment processes. The entire technological process for the extraction, purification and enrichment of PUFA oils from algae is systemically summarized in this review, providing important guidance and technical reference for scientific research and industrialization of algae-based PUFA production.

Role of Omega-3 Fatty Acids as Non-Photic Zeitgebers and Circadian Clock Synchronizers

Omega-3 fatty acids (ω-3 FAs) are well-known for their actions on immune/inflammatory and neurological pathways, functions that are also under circadian clock regulation. The daily photoperiod represents the primary circadian synchronizer (‘zeitgeber’), although diverse studies have pointed towards an influence of dietary FAs on the biological clock. A comprehensive literature review was conducted following predefined selection criteria with the aim of updating the evidence on the molecular mechanisms behind circadian rhythm regulation by ω-3 FAs. We collected preclinical and clinical studies, systematic reviews, and metanalyses focused on the effect of ω-3 FAs on circadian rhythms. Twenty animal (conducted on rodents and piglets) and human trials and one observational study providing evidence on the regulation of neurological, inflammatory/immune, metabolic, reproductive, cardiovascular, and biochemical processes by ω-3 FAs via clock genes were discussed. The evidence suggests that ω-3 FAs may serve as non-photic zeitgebers and prove therapeutically beneficial for circadian disruption-related pathologies. Future work should focus on the role of clock genes as a target for the therapeutic use of ω-3 FAs in inflammatory and neurological disorders, as well as on the bidirectional association between the molecular clock and ω-3 FAs.

Comparison of Donepezil, Memantine, Melatonin, and Liuwei Dihuang Decoction on Behavioral and Immune Endocrine Responses of Aged Senescence-Accelerated Mouse Resistant 1 Mice

Aging is a natural biological process associated with cognitive decline and neuroendocrine–immune system changes; the neuroendocrine–immune system plays crucial role in brain aging and neurodegeneration, and it is essential to discern beneficial attempts to delay the aging progress based on immunological aging. In this study, we have investigated the effects of Traditional Chinese Medicine (TCM)—Liuwei Dihuang decoction (LW)—and donepezil, memantine, and melatonin on cognitive decline in aging mice. The aged SAMR1 mice received oral administration of donepezil (1mg/kg), memantine (10 mg/kg), melatonin (10 mg/kg), and LW (10 g/kg) for 3 months. A shuttle box, Morris water maze, and elevated-zero maze were performed to assess cognitive function, and flowcytometry, Luminex, and radioimmunoassay were performed to measure the lymphocyte subsets, inflammatory factors, and hormones. We observed that survival days of mice was increased with melatonin and LW, the anxiety behavior was significantly improved by memantine, melatonin, and LW treatment, active avoidance responses significantly improved by LW, donepezil, and memantine, the spatial learning ability was significantly improved by donepezil, and LW and melatonin were beneficial to the spatial memory of old mice. For immune function, LW increased CD4⁺ and CD4⁺CD28⁺ cells and reduced TNF-α, IL-1β, and G-CSF in plasma, and it also promoted the secretion of anti-inflammatory factors IL-4, IL-5, and IL-10 by regulating the active of Th2 cells in spleen. Donepezil and memantine exerted protective effects against CD4⁺CD28⁺ cell decrease caused by aging and reduced the pro-inflammatory factors TNF-α, IL-1β, and G-CSF in plasma. Melatonin could reverse CD8⁺CD28⁺ cell imbalances and increased B cells. For endocrine factors, LW increased TSH levels in the pituitary, and melatonin increased the GH level in blood. Our findings indicated that LW improved the cognitive decline in aging mice, and this might be associated with modulation of the active T cells and HPG axis hormones as well as increasing anti-inflammatory factors. Meanwhile, donepezil and memantine have advantages in regulating adaptive immunity, melatonin has advantages in the regulation of B cells and pituitary hormones, and LW exhibits a better effect on neuroendocrine immune function compared with the others from a holistic point of view. LW might be a potential therapeutic strategy for anti-aging-related syndromes, and it can also provide a value on medication guidance about drug combinations or treatment in clinic.

Brain metabolomic profiling of eastern honey bee (Apis cerana) infested with the mite Varroa destructor

The mite Varroa destructor is currently the greatest threat to apiculture as it is causing a global decrease in honey bee colonies. However, it rarely causes serious damage to its native hosts, the eastern honey bees Apis cerana. To better understand the mechanism of resistance of A. cerana against the V. destructor mite, we profiled the metabolic changes that occur in the honey bee brain during V. destructor infestation. Brain samples were collected from infested and control honey bees and then measured using an untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based global metabolomics method, in which 7918 and 7462 ions in ESI+ and ESI- mode, respectively, were successfully identified. Multivariate statistical analyses were applied, and 64 dysregulated metabolites, including fatty acids, amino acids, carboxylic acid, and phospholipids, amongst others, were identified. Pathway analysis further revealed that linoleic acid metabolism; propanoate metabolism; and glycine, serine, and threonine metabolism were acutely perturbed. The data obtained in this study offer insight into the defense mechanisms of A. cerana against V. destructor mites and provide a better method for understanding the synergistic effects of parasitism on honey bee colonies.

Chronic exposure to manganese sulfate leads to adverse dose-dependent effects on the neurobehavioral ability of rats

Manganese sulfate is the main combustion product of methylcyclopentadienyl manganese tricarbonyl (MMT). Currently, little is known about the neurobehavioral consequences of chronic manganese sulfate exposure. In this study, rats were treated with 0, 5.0, 10.0, and 20.0 mg/kg MnSO₄ ·H₂ O for 24 consecutive weeks via intraperitoneal injection. During the treatment period, spatial learning-memory ability was measured using the Morris water maze (MWM). At the end of the exposure period, spontaneous motor behavior and emotional status, hippocampal histologic changes, and Hsp70 mRNA levels were measured using the open-field test (OFT), hematoxylin-eosin staining and real-time quantitative PCR (RT-PCR), respectively. A dose-dependent decrease was noted in the spatial learning-memory ability and the spontaneous activities of rats (P < 0.05), and negative emotions differed significantly between the exposed groups and the control group (P < 0.05). Moreover, overt morphological changes in the hippocampuses of the exposed rats were detected. Cellular degeneration and death were also found. The Hsp70 mRNA levels of the hippocampal areas in the 20.0 mg/kg group (1.567 ± 0.236) were significantly increased compared with the control group (P < 0.05). These results suggest that chronic exposure to manganese sulfate can have adverse dose-dependent effects on rats' neurobehavioral ability, and the mechanism of abnormal hippocampal Hsp70 expression needs to be further explored. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1571-1579, 2016.

Linoleic and docosahexaenoic acids in human milk have opposite relationships with cognitive test performance in a sample of 28 countries

Polyunsaturated fatty acids play critical roles in brain development and function, and their levels in human breast milk closely reflect the long-term diet. The fatty acid contents of human milk samples from 28 countries were used to predict averaged 2009 and 2012 test scores in mathematics, reading, and science from the Program for International Student Assessment. All test scores were positively related to milk docosahexaenoic acid (r=0.48 to 0.55), and negatively related to linoleic acid (r=-0.28 to -0.56). Together, these two human milk fatty acids explained 46% to 48% of the variance in scores, with no improvement in predictive power when socioeconomic variables were added to the regression. The (log) ratio of linoleic to arachidonic acid was negatively related to scores (r=-0.45 to -0.48). Statistical effects were similar for the two sexes. In a separate US sample, estimated dietary linoleic was negatively related to the levels of all long-chain n-3 and n-6 plasma fatty acids. High levels of dietary linoleic may impair cognition by decreasing both docosahexaenoic and arachidonic acids in the brain.

Brain deposition and neurotoxicity of manganese in adult mice exposed via the drinking water

Natural leaching processes and/or anthropogenic contamination can result in ground water concentrations of the essential metal manganese (Mn) that far exceed the current regulatory standards. Neurological consequences of Mn drinking water (DW) overexposure to experimental animals, i.e., mice, including its brain deposition/distribution and behavioral effects are understudied. Adult male C57BL/6 mice were exposed to Mn via the DW for 8 weeks. After 5 weeks of Mn exposure, magnetic resonance imaging revealed significant Mn deposition in all examined brain regions; the degree of Mn deposition did not increase further a week later. Behaviorally, early hyperactivity and more time spent in the center of the arenas in an open field test, decreased forelimb grip strength and less time swimming in a forced swim test were observed after 6 weeks of Mn DW exposure. Eight-week Mn DW exposure did not alter striatal dopamine, its metabolites, or the expression of key dopamine homeostatic proteins, but it significantly increased striatal 5-hydroxyindoleacetic acid (a serotonin metabolite) levels, without affecting the levels of serotonin itself. Increased expression (mRNA) of glial fibrillary acidic protein (GFAP, an astrocyte activation marker), heme oxygenase-1 and inducible nitric oxide synthase (oxidative and nitrosative stress markers, respectively) were observed 8 weeks post-Mn DW exposure in the substantia nigra. Besides mRNA increases, GFAP protein expression was increased in the substantia nigra pars reticulata. In summary, the neurobehavioral deficits, characterized by locomotor and emotional perturbations, and nigral glial activation associated with significant brain Mn deposition are among the early signs of Mn neurotoxicity caused by DW overexposure.

Omega-3 fatty acids in neurodegenerative diseases: focus on mitochondria

Mitochondrial dysfunction represents a common early pathological event in brain aging and in neurodegenerative diseases, e.g., in Alzheimer's (AD), Parkinson's (PD), and Huntington's disease (HD), as well as in ischemic stroke. In vivo and ex vivo experiments using animal models of aging and AD, PD, and HD mainly showed improvement of mitochondrial function after treatment with polyunsaturated fatty acids (PUFA) such as docosahexaenoic acid (DHA). Thereby, PUFA are particular beneficial in animals treated with mitochondria targeting toxins. However, DHA showed adverse effects in a transgenic PD mouse model and it is not clear if a diet high or low in PUFA might provide neuroprotective effects in PD. Post-treatment with PUFA revealed conflicting results in ischemic animal models, but intravenous administered DHA provided neuroprotective efficacy after acute occlusion of the middle cerebral artery. In summary, the majority of preclinical data indicate beneficial effects of n-3 PUFA in neurodegenerative diseases, whereas most controlled clinical trials did not meet the expectations. Because of the high half-life of DHA in the human brain clinical studies may have to be initiated much earlier and have to last much longer to be more efficacious.

Alterations in Lipid Levels of Mitochondrial Membranes Induced by Amyloid-β: A Protective Role of Melatonin

Alzheimer pathogenesis involves mitochondrial dysfunction, which is closely related to amyloid-β (Aβ) generation, abnormal tau phosphorylation, oxidative stress, and apoptosis. Alterations in membranal components, including cholesterol and fatty acids, their characteristics, disposition, and distribution along the membranes, have been studied as evidence of cell membrane alterations in AD brain. The majority of these studies have been focused on the cytoplasmic membrane; meanwhile the mitochondrial membranes have been less explored. In this work, we studied lipids and mitochondrial membranes in vivo, following intracerebral injection of fibrillar amyloid-β (Aβ). The purpose was to determine how Aβ may be responsible for beginning of a vicious cycle where oxidative stress and alterations in cholesterol, lipids and fatty acids, feed back on each other to cause mitochondrial dysfunction. We observed changes in mitochondrial membrane lipids, and fatty acids, following intracerebral injection of fibrillar Aβ in aged Wistar rats. Melatonin, a well-known antioxidant and neuroimmunomodulator indoleamine, reversed some of these alterations and protected mitochondrial membranes from obvious damage. Additionally, melatonin increased the levels of linolenic and n-3 eicosapentaenoic acid, in the same site where amyloid β was injected, favoring an endogenous anti-inflammatory pathway.

Therapeutic use of omega-3 fatty acids in bipolar disorder

Bipolar disorder (BD) is a severe, chronic affective disorder, associated with significant disability, morbidity and premature mortality. Omega-3 polyunsaturated fatty acids (PUFAs) play several important roles in brain development and functioning. Evidence from animal models of dietary omega-3 (n-3) PUFA deficiency suggest that these fatty acids are relevant to promote brain development and to regulate behavioral and neurochemical aspects related to mood disorders, such as stress responses, depression and aggression, as well as dopaminergic content and function. Preclinical and clinical evidence suggests roles for PUFAs in BD. n-3 PUFAs seem to be an effective adjunctive treatment for unipolar and bipolar depression, but further large-scale, well-controlled trials are needed to examine its clinical utility in BD. The use of n-3 as a mood stabilizer among BD patients is discussed here. This article summarizes the molecular pathways related to the role of n-3 as a neuroprotective and neurogenic agent, with a specific focus on BDNF. It is proposed that the n-3-BDNF association is involved in the pathophysiology of BD and represents a promising target for developing a novel class of rationally devised therapies.

Erythrocyte α-linolenic acid is associated with the risk for mild dementia in Korean elderly

n-3 polyunsaturated fatty acids (PUFA) play an important role in brain development and function, but there is conflicting evidence between the relationship of n-3 PUFA and dementia in the elderly. The purpose of the present study was to test the hypothesis that n-3 PUFA content of erythrocytes is associated with mild dementia in elderly Koreans. Fifty-seven elderly (age ≥65 years) patients (19 male, 38 female) were recruited, and indicators of dementia (intake, erythrocyte fatty acid composition, and Mini-Mental Status Examination-Korean Version [MMSE-K]) were evaluated. Patients were divided into groups based on their MMSE-K score: normal control group (score >21 [n = 24]) and deficit group (score ≤21 [n = 33]). Multivariate-adjusted regression analysis showed that a higher level of α-linolenic acid (ALA; 18:3n-3) significantly decreased the risk of mild dementia after adjusting for age, sex, and height. MMSE-K score was also significantly and positively associated with erythrocyte ALA and total n-3 PUFA. However, erythrocyte levels of docosahexaenoic acid (22:6n-3) and eicosapentaenoic acid (20:5n-3) were not significantly related with the risk of mild dementia and MMSE-K score. Dietary intake was also not significantly associated with the risk of mild dementia and MMSE-K score after adjusting for age, sex, height, and energy intake. In conclusion, ALA derived from plant sources of n-3 PUFA, but not eicosapentaenoic acid and docosahexaenoic acid from fish, decreased the risk for mild dementia among the Korean elderly.

Dietary polyunsaturated fatty acids improve cholinergic transmission in the aged brain

The cholinergic theory of aging states that dysfunction of cholinergic neurons arising from the basal forebrain and terminating in the cortex and hippocampus may be involved in the cognitive decline that occurs during aging and Alzheimer's disease. Despite years of research, pharmacological interventions to treat or forestall the development of Alzheimer's disease have primarily focused on enhancing cholinergic transmission, either through increasing acetylcholine (ACh) synthesis or inhibition of the acetylcholinesterase enzyme responsible for ACh hydrolysis. However, recent studies have indicated that dietary supplementation can impact the cholinergic system, particularly during aging. The purpose of the present review is to examine the relevant research suggesting that cholinergic functioning may be maintained during aging via consuming a diet containing polyunsaturated fatty acids (PUFAs). The data reviewed herein indicate that, at least in animal studies, inclusion of PUFAs in the diet can improve cholinergic transmission in the brain, possibly leading to improvements in cognitive functioning.

Low plasma N-3 fatty acids and dementia in older persons: the InCHIANTI study

BACKGROUND

N-3 fatty acids (FA) have an important role in brain development and function. However, there is conflicting evidence concerning the relationship between n-3 FA and dementia in older persons.

METHODS

In the Invecchiare in Chianti (InCHIANTI) study, we measured plasma FA by gas chromatography in 935 community-dwelling older persons randomly extracted from the population of two towns near Florence, Italy. Cognitive impairment was measured using the Mini-Mental Status Examination. Participants who scored </=26 underwent a detailed clinical and neuropsychological evaluation. The diagnosis of dementia was based on Diagnostic and Statistical Manual of Mental Disorders, Third Revision (DSM-III-R) criteria. The population was divided in three groups: persons with normal cognitive function, persons with cognitive impairment not demented, and persons with dementia.

RESULTS

After adjustment for age, gender, education, body mass index, weight loss, smoking status, cholesterol and triglycerides levels, daily intake of alcohol, FA and total energy, cardiovascular disease, depression and other FA levels, participants with dementia had significantly lower n-3 FA levels (2.9% vs 3.2%; p <.05), particularly alpha-linolenic acid levels (0.34% vs 0.39%; p <.05), than did participants with normal cognitive function.

CONCLUSIONS

Dementia is associated with low plasma n-3 FA relative concentrations. The possibility that higher n-3 FA intake is associated with a lower risk of cognitive impairment should be further investigated in prospective studies.

Association of fatty acid desaturase genes with attention-deficit/hyperactivity disorder

BACKGROUND

Fatty acids, in particular omega-3 fatty acids, have been found to affect behavior and cognition both directly and indirectly. Evidence to suggest a link with attention-deficit/hyperactivity disorder (ADHD) derives from three key areas: 1) animal dietary restriction studies observed increased locomotive hyperactivity and reduced cognitive ability in offspring; 2) animal dietary studies indicate alterations in the dopamine pathway; and 3) human studies report reduced plasma omega-3 fatty acids in ADHD subjects.

METHODS

We investigated three genes that encode essential enzymes (desaturases) for the metabolism of fatty acids by scanning for genetic association between 45 single nucleotide polymorphisms (SNPs) and ADHD.

RESULTS

Our findings suggest a significant association of ADHD with SNP rs498793 (case-control p = .004, odds ratio [OR] 1.6, 95% confidence interval [CI] 1.15-2.23; transmission disequilibrium test [TDT] p = .014, OR 1.69) in the fatty acid desaturase 2 (FADS2) gene. As alcohol is known to decrease the activities of these desaturase enzymes, we also tested for interactions between ADHD subjects' genotypes and maternal use of alcohol during pregnancy. Two SNPs in the fatty acid desaturase 1 (FADS1) gene were nominally associated with ADHD only in the prenatal alcohol-exposed group of children; formal test for interaction was not significant.

CONCLUSIONS

These preliminary findings are suggestive of an association between FADS2 and ADHD.

Maternal and Genetic Effects on Anxiety-Related Behavior of C3H/HeN, DBA/2J and NMRI Mice in a Motility-Box Following Blastocyst Transfer

Reciprocal embryo transfers were conducted to examine genetic and maternal effects on the behavior of inbred C3H/HeN and DBA/2J mice, and outbred NMRI mice using a motility-box. The behavioral variables measured were (i) horizontal locomotor activity assessed as the path and time spent during traveling; (ii) vertical activity assessed as the time spent with and numbers of rearings/leanings; (iii) and the time spent in the more anxiogenic central field. The transfer procedure per se resulted in a minor increase in vertical activity of inbred C3H/HeN mice, but had no effect in inbred DBA/2J mice. In contrast, outbred NMRI mice displayed a lower central field activity following embryo transfer indicating a higher anxiety level. Moreover, genetic differences between the mouse strains studied remained stable following embryo transfer for locomotor and vertical activity, but not central field activity depending on the recipient mother strain. Maternal effects were found for (i) vertical activity in the two inbred mouse strains, (ii) all behavioral variables studied in outbred NMRI mice, and (iii) an interaction with gender for the time spent in the anxiogenic central field. An additional fostering procedure revealed that the vertical activity of NMRI mice was modified towards the behavior of the recipient C3H/HeN strain by uterine factors, whereas the postnatal maternal effect of C3H/HeN mothers was the opposite. In summary, the effects of the embryo transfer procedure per se, stability of genetic characteristics following embryo transfer and maternal effects were related to the mouse strains used as donators and recipients, and the behavioral variables studied.

Dietary fat intake is associated with psychosocial and cognitive functioning of school-aged children in the United States

Using cross-sectional data from the Third National Health and Nutrition Survey, 1988-1994, we examined whether dietary fat intake is associated with cognitive and psychosocial functioning in school-aged children. Based upon 24-h diet recall interviews, dietary intakes of total fat, SFA, monounsaturated fatty, PUFAs, and cholesterol were estimated in 3666 participants aged 6 to 16 y. Psychosocial functioning was evaluated in interviews of each child's mother. Cognitive functioning was measured using achievement and intelligence tests. Overall, total fat and saturated fat were unrelated to measures of cognitive and psychosocial functioning. Compared with equivalent energy intake from saturated fat or carbohydrate, each 5% increase in energy intake from PUFAs was associated with lower risks of poor performance on the digit span test (replacing SFA, OR = 0.58, 95% CI = 0.37-0.91; replacing carbohydrate, OR = 0.61, 95% CI = 0.43-0.88). Cholesterol intake was associated with an increased risk of poor performance on the digit span test (OR = 1.25, 95% CI = 1.11-1.42 for each 100-mg increment intake of cholesterol). The associations were independent of socioeconomic status, maternal education and marital status, and children's nutrition status and were consistent across different methods of energy adjustment in regression models. We conclude that high intake of PUFAs may contribute to an improved performance on the digit span test. In contrast, increased intake of cholesterol may be associated with a poorer performance.

Cholesterol and cholesterol plus DHA diet-induced gene expression and fatty acid changes in mouse eye and brain

Both cholesterol and polyunsaturated fatty acid (PUFA) metabolism play an important role in retinal and brain development and function. Dietary intake of cholesterol is accompanied with higher risk of heart disease and was suggested to have a role in the pathogenesis of Alzheimer's disease, while dietary PUFAs were reported to act in an opposite way. The same phenomena could be seen in case of inflammation. These effects are mainly realized through gene expression changes. In the present study, the effects of dietary cholesterol and the combination of cholesterol and fish oil were analyzed on the modulation of fatty acid composition and gene expression in the brain and in the eye. At the transcription level, specific changes could be detected in both tissues among transcription factor genes coding for sterol regulatory element binding proteins, retinoid X receptors and peroxisome proliferator-activated receptors, and different fatty acid binding protein genes by using quantitative real-time PCR. In the eye, cholesterol diet attenuated the positive effects of fish oil on inflammatory gene expression as the combined diet resulted in increased RNAm level of phospholipase A-2, inducible nitric oxide synthase, TNF-alpha, COX-1, COX-2 and cytokine, ICAM-1. This induction was absent in the brain. Complex changes could be also recorded in the fatty acid composition of lipids extracted from eye and brain tissue due to the dietary intervention. One of the most interesting changes was the reduced level of docosahexaenoic acid by cholesterol in the eye. Our results on fatty acid composition and gene expression changes may open up new alleys in understanding the complex roles of cholesterol and PUFAs in normal and pathological visual and brain function.

Effects of dietary omega-3 polyunsaturated fatty acids on brain gene expression

Polyunsaturated fatty acids (PUFA) are essential structural components of the central nervous system. Their role in controlling learning and memory has been well documented. A nutrigenomic approach with high-density microarrays was used to reveal brain gene-expression changes in response to different PUFA-enriched diets in rats. In aged rats fed throughout life with PUFA-enriched diets, genes with altered expressions included transthyretin, alpha-synuclein, and calmodulins, which play important roles in synaptic plasticity and learning. The effect of perinatal omega-3 PUFA supply on gene expression later in life also was studied. Several genes showed similar changes in expression in rats fed omega-3-deficient diets in the perinatal period, regardless of whether they or their mothers were fed omega-3 PUFA-sufficient diets after giving birth. In this experiment, among the down-regulated genes were a kainate glutamate receptor and a DEAD-box polypeptide. Among the up-regulated genes were a chemokine-like factor, a tumor necrosis factor receptor, and cytochrome c. The possible involvement of the genes with altered expression attributable to different diets in different brain regions in young and aged rats and the possible mode of regulatory action of PUFA also are discussed. We conclude that PUFA-enriched diets lead to significant changes in expression of several genes in the central nervous tissue, and these effects appear to be mainly independent of their effects on membrane composition. The direct effects of PUFA on transcriptional modulators, the downstream developmentally and tissue-specifically activated elements might be one of the clues to understanding the beneficial effects of the omega-3 PUFA on the nervous system.

Ethyl-eicosapentaenoic acid ingestion prevents corticosterone-mediated memory impairment induced by central administration of interleukin-1beta in rats

Central or peripheral administration of the proinflammatory cytokine interleukin (IL)-1beta can impair performance on spatial memory tasks and also elevate circulating concentration of corticosterone. The present experiment provides independent confirmation that intracerebroventricular administration of 10 ng IL-1beta in the rat can have a selective effect on the retrieval of trial unique information about the location of food on an eight-arm radial maze. The probable involvement of corticosterone in IL-1beta-induced memory impairment was indicated by elevated corticosterone levels after IL-1beta administration. Further evidence comes from the blockade of the associated impairment in working memory by coadministration of the glucocorticoid receptor antagonist RU486. Ingestion of diet containing omega-3 fatty acid eicosapentaenoic acid (EPA) is known to antagonize the synthesis of prostaglandin (PG) E2 from aracadonic acid, and the present study confirmed that ethyl EPA (1%) reduced IL-1beta-elevated concentrations of PGE2 and corticosterone. Furthermore, rats given the ethyl-EPA diet for 8 weeks were unaffected by the disruptive effects of IL-1beta on working memory. IL-1beta-induced suppression of mitogen-stimulated release of the anti-inflammatory cytokine IL-10 was also blocked by treatment with ethyl-EPA. Collectively, these data demonstrate that IL-1beta can impair memory function by elevating the concentration of corticosterone and that prior consumption of 1% ethyl-EPA can block both the neuroendocrine and cognitive effects of IL-1beta. These findings in turn may indicate beneficial effects of ethyl-EPA in the treatment of cognitive and affective disorders in which inflammation and stress play a critical role.

What is the role of alpha-linolenic acid for mammals?

This review examines the data pertaining to an important and often underrated EFA, alpha-linolenic acid (ALA). It examines its sources, metabolism, and biological effects in various population studies, in vitro, animal, and human intervention studies. The main role of ALA was assumed to be as a precursor to the longer-chain n-3 PUFA, EPA and DHA, and particularly for supplying DHA for neural tissue. This paper reveals that the major metabolic route of ALA metabolism is beta-oxidation. Furthermore, ALA accumulates in specific sites in the body of mammals (carcass, adipose, and skin), and only a small proportion of the fed ALA is converted to DHA. There is some evidence that ALA may be involved with skin and fur function. There is continuing debate regarding whether ALA has actions of its own in relation to the cardiovascular system and neural function. Cardiovascular disease and cancer are two of the major burdens of disease in the 21st century, and emerging evidence suggests that diets containing ALA are associated with reductions in total deaths and sudden cardiac death. There may be aspects of the action and, more importantly, the metabolism of ALA that need to be elucidated, and these will help us understand the biological effects of this compound better. Additionally, we must not forget that ALA is part of the whole diet and should be seen in this context, not in isolation.

Docosahexaenoic acid-rich phospholipid supplementation: effect on behavior, learning ability, and retinal function in control and n-3 polyunsaturated fatty acid deficient old mice

This study investigated the effects of docosahexaenoic acid (DHA)-rich phospholipid supplementation on behavior, electroretinogram and phospholipid fatty acid (PUFA) composition in selected brain regions and retina in old mice. Two groups of mice were fed a semisynthetic balanced diet or a diet deficient in alpha-linolenic acid. At the age of 8 months, half of each diet group was supplemented with DHA. In the open field, no differences in motor or exploratory activities were observed between the four diet groups. In the light/dark test of anxiety, the time spent in the light compartment was significantly higher in both supplemented groups than in control and deficient groups. Learning performance in the Morris water maze was significantly impaired in deficient old mice, but was completely restored by the phospholipid supplementation. The electroretinogram showed a significant alteration of a- and b-wave amplitudes in control compared to deficient mice. Phospholipid supplementation induced a significant increase of b-wave amplitude in both control and deficient groups and restored normal fatty acid composition in brain regions and retina in deficient mice. DHA-rich phospholipids may improve learning ability, visual function and reverse biochemical modifications in old mice fed an n-3 polyunsaturated fatty acid-deficient diet; they also may improve visual function in old mice fed a balanced diet.

Emotional reactivity in mice, a case of nongenetic heredity?

Nongenetic heredity cases have been described in man, as well as in animals, and relationships between parents and offspring seem to play an important role in this transmission. In mice, mothering type could be nongenetically heritable by a latent learning close to mechanism. As mothering style clearly influences emotional reactivity, this reactivity could be nongenetically transmitted over generations. To clarify this question, the mother's influence on adult offspring reactivity must be established (whatever its basis, genetic, social or other). Thus, two reciprocal F1 hybrids (CB6 from a BALB/c mother and B6C from a C57BL/6 mother) have been compared using an ethological analysis in animal tests of emotional reactivity such as the free exploration paradigm and the light/dark box. First results show a sharp influence of the mother's strain and that suggests an effect of mothering style. The offspring from C57BL/6 mothers display less reactivity in the free exploration paradigm than the offspring from BALB/c mothers. In the light/dark box, no difference has been found between the two hybrids. Moreover, the mother's influence is greater in males than in females.