Maternal docosahexaenoic acid feeding protects against impairment of learning and memory and oxidative stress in prenatally stressed rats: possible role of neuronal mitochondria metabolism

Maternal n-3 polyunsaturated fatty acid deprivation during pregnancy and lactation affects neurogenesis and apoptosis in adult offspring: associated with DNA methylation of brain-derived neurotrophic factor transcripts

In this study, we hypothesized that n-3 polyunsaturated fatty acid (PUFA) deficiency during pregnancy and lactation will make a lasting impact on brain neurogenesis and apoptosis of the adult offspring and that these harmful effects cannot be reversed by n-3 PUFA supplementation after weaning. Moreover, the underlying mechanisms may be attributable to the epigenetic changes of brain-derived neurotrophic factor (BDNF). C57BL/6J female mice were fed with n-3 PUFA-deficient diet (n-3 def) or n-3 PUFA-adequate diet (n-3 adq) throughout pregnancy and lactation. At postnatal 21 days, equal numbers of male pups from both groups were fed the opposite diet, and the remaining male pups were fed with the same diets as their mothers until 3 months of age. Feeding the n-3 adq diet to pups from the maternal n-3 def group significantly increased the n-3 PUFA concentration but did not change expressions of calretinin, Bcl2, and Bax in the hippocampus. Feeding the n-3 def diet to pups from the maternal n-3 adq group significantly reduced the n-3 PUFA concentration but did not reduce expressions of calretinin and Bcl2. Similarly, BDNF levels, especially mRNA expressions of BDNF transcripts IV and IX, were also reduced by maternal n-3 def and not reversed by n-3 PUFA supplementation after weaning. The decrease in BDNF expression by maternal n-3 def diet was associated with greater DNA methylation at special CpG sites. These results suggested that the maternal n-3 PUFA deficiency during pregnancy and lactation imprints long-term changes of brain development in adult offspring.

Early postnatal docosahexaenoic acid levels and improved preterm brain development

BACKGROUND

Preterm birth has a dramatic impact on polyunsaturated fatty acid exposures for the developing brain. This study examined the association between postnatal fatty acid levels and measures of brain injury and development, as well as outcomes.

METHODS

A cohort of 60 preterm newborns (24-32 wk gestational age) was assessed using early and near-term magnetic resonance imaging (MRI) studies. Red blood cell fatty acid composition was analyzed coordinated with each scan. Outcome at a mean of 33 mo corrected age was assessed using the Bayley Scales of Infant Development, 3rd edition.

RESULTS

Adjusting for confounders, a 1% increase in postnatal docosahexaenoic acid (DHA) levels at early MRI was associated with 4.3-fold decreased odds of intraventricular hemorrhage, but was not associated with white matter injury or cerebellar haemorrhage. Higher DHA and lower linoleic acid (LA) levels at early MRI were associated with lower diffusivity in white matter tracts and corresponding improved developmental scores in follow-up.

CONCLUSION

Higher DHA and lower LA levels in the first few weeks of life are associated with decreased intraventricular haemorrhage, improved microstructural brain development, and improved outcomes in preterm born children. Early and possibly antenatal interventions in high-risk pregnancies need to be studied for potential benefits in preterm developmental outcomes.

Novel insights into the effect of vitamin B₁₂ and omega-3 fatty acids on brain function

The prevalence of psychiatric disorders which are characterized by cognitive decline is increasing at an alarming rate and account for a significant proportion of the global disease burden. Evidences from human and animal studies indicate that neurocognitive development is influenced by various environmental factors including nutrition. It has been established that nutrition affects the brain throughout life. However, the mechanisms through which nutrition modulates mental health are still not well understood. It has been suggested that the deficiencies of both vitamin B12 and omega-3 fatty acids can have adverse effects on cognition and synaptic plasticity. Studies indicate a need for supplementation of vitamin B12 and omega-3 fatty acids to reduce the risk of cognitive decline, although the results of intervention trials using these nutrients in isolation are inconclusive. In the present article, we provide an overview of vitamin B12 and omega-3 fatty acids, the possible mechanisms and the evidences through which vitamin B12 and omega-3 fatty acids modulate mental health and cognition. Understanding the role of vitamin B12 and omega-3 fatty acids on brain functioning may provide important clues to prevent early cognitive deficits and later neurobehavioral disorders.

Long-term effects of early life stress exposure: Role of epigenetic mechanisms

Stress is an adaptive response to demands of the environment and thus essential for survival. Exposure to stress during the first years of life has been shown to have profound effects on the growth and development of an adult individual. There are evidences demonstrating that stressful experiences during gestation or in early life can lead to enhanced susceptibility to mental disorders. Early-life stress triggers hypothalamic-pituitary-adrenocortical (HPA) axis activation and the associated neurochemical reactions following glucocorticoid release are accompanied by a rapid physiological response. An excessive response may affect the developing brain resulting in neurobehavioral and neurochemical changes later in life. This article reviews the data from experimental studies aimed to investigate hormonal, functional, molecular and epigenetic mechanisms involved in the stress response during early-life programming. We think these studies might prove useful for the identification of novel pharmacological targets for more effective treatments of mental disorders.

The impact of mitochondrial aldehyde dehydrogenase (ALDH2) activation by Alda-1 on the behavioral and biochemical disturbances in animal model of depression

The etiology of depression remains still unclear. Recently, it has been proposed, that mitochondrial dysfunction may be associated with development of mood disorders, such as depression, bipolar disorder and anxiety disorders. Mitochondrial aldehyde dehydrogenase (ALDH2), an enzyme responsible for the detoxification of reactive aldehydes, is considered to exert protective function in mitochondria. We investigated the influence of Alda-1, a small-molecule activator of ALDH2, on depressive- and anxiety-like behaviors in an animal model of depression - the prenatally stressed rats - using behavioral, molecular and proteomic methods. Prolonged Alda-1 administration significantly increased the climbing time, tended to reduce the immobility time and increased the swimming time of the prenatally stressed rats in the forced swim test. Moreover, treatment of prenatally stressed rats with Alda-1 significantly increased number of entries into the open arms of the maze and the time spent therein, as assessed by elevated plus-maze test. Such actions were associated with reduction of plasma 4-HNE-protein content, decrease of TNF-α mRNA and increase of PGC-1α (regulator of mitochondrial biogenesis) mRNA level in the frontal cortex and hippocampus of the prenatally stressed rats as well as with normalization of peripheral immune parameters and significant changes in expression of 6 and 4 proteins related to mitochondrial functions in the frontal cortex and hippocampus, respectively. Collectively, ALDH2 activation by Alda-1 led to a significant attenuation of depressive- and anxiety-like behaviors in the prenatally stressed rats. The pattern of changes suggested mitoprotective effect of Alda-1, however the exact functional consequences of the revealed alterations require further investigation.

Long-Term Dietary Alpha-Linolenic Acid Supplement Alleviates Cognitive Impairment Correlate with Activating Hippocampal CREB Signaling in Natural Aging Rats

Alpha-linolenic acid (ALA) is a major precursor of the essential n-3 polyunsaturated fatty acid (PUFA), whose deficiency alters the structure and function of membranes and induces cerebral dysfunctions. The major purpose of this study was to investigate the protective effect of prolonged ALA intake on cognitive function during natural aging. Female Sprague-Dawley rats aged 6 months were chronically treated with ALA and/or lard per day for 12 months. Regular diet-treated rats, both young and old (4 and 18 months old, respectively) served as controls. Rats fed on regular diet during aging showed memory deficits in Morris water maze, which were further exacerbated by lard intake. However, supplementation with ALA for 12 months dose-dependently improved the performance in spatial working memory tasks. Memory performance correlated well with the activation of cAMP response element-binding protein (CREB) and increases in both levels of brain-derived neurotrophic factor (BDNF) and its specific receptor tyrosine kinase B (TrkB) phosphorylation in the hippocampus. Further study identified that hippocampal extracellular signal-related kinase (ERK) and Akt rather than calcium calmodulin kinase IV (CaMKIV) and protein kinase A (PKA), the upstream signalings of CREB, were also activated by ALA supplement. Moreover, memory improvement was accompanied with alterations of hippocampal synaptic structure and number, suggestive of enhancement in synaptic plasticity. Together, these results suggest that long-term dietary intake of ALA enhances CREB/BDNF/TrkB pathway through the activation of ERK and Akt signalings in hippocampus, which contributes to its ameliorative effects on cognitive deficits in natural aging.

Integrating mitochondriomics in children's environmental health

The amount of scientific research linking environmental exposures and childhood health outcomes continues to grow; yet few studies have teased out the mechanisms involved in environmentally-induced diseases. Cells can respond to environmental stressors in many ways: inducing oxidative stress/inflammation, changes in energy production and epigenetic alterations. Mitochondria, tiny organelles that each retains their own DNA, are exquisitely sensitive to environmental insults and are thought to be central players in these pathways. While it is intuitive that mitochondria play an important role in disease processes, given that every cell of our body is dependent on energy metabolism, it is less clear how environmental exposures impact mitochondrial mechanisms that may lead to enhanced risk of disease. Many of the effects of the environment are initiated in utero and integrating mitochondriomics into children's environmental health studies is a critical priority. This review will highlight (i) the importance of exploring environmental mitochondriomics in children's environmental health, (ii) why environmental mitochondriomics is well suited to biomarker development in this context, and (iii) how molecular and epigenetic changes in mitochondria and mitochondrial DNA (mtDNA) may reflect exposures linked to childhood health outcomes.

Modulation of prenatal stress via docosahexaenoic acid supplementation: implications for child mental health

Pregnant women living in poverty experience chronic and acute stressors that may lead to alterations in circulating glucocorticoids. Experimental evidence from animal models and correlational studies in humans support the hypothesis that prenatal exposure to high levels of glucocorticoids can negatively affect the developing fetus and later emotional and behavioral regulation in the offspring. In this integrative review, recent findings from research in psychiatry, obstetrics, and animal and human experimental studies on the role of docosahexaenoic acid in modulation of the stress response and brain development are discussed. The potential for an emerging field of nutritionally based perinatal preventive interventions for improving offspring mental health is described. Prenatal nutritional interventions may prove to be effective approaches to reducing common childhood mental disorders.

AMPK activation prevents prenatal stress-induced cognitive impairment: modulation of mitochondrial content and oxidative stress

Prenatal stress induces cognitive functional impairment in offspring, an eventuality in which mitochondrial dysfunction and oxidative stress are believed to be closely involved. In this study, the involvement of the AMP-activated protein kinase (AMPK) pathway was investigated. A well-known activator, resveratrol (Res), was used to induce AMPK activation in SH-SY-5Y cells. Significant mitochondrial biogenesis and phase II enzyme activation, accompanied by decreased protein oxidation and GSSG content, were observed after Res treatment, and inhibition of AMPK with Compound c abolished the induction effects of Res. Further study utilizing a prenatal restraint stress (PRS) animal model indicated that maternal supplementation of Res may activate AMPK in the hippocampi of both male and female offspring, and that PRS-induced mitochondrial loss in the offspring hippocampus was inhibited by Res maternal supplementation. In addition, Res activated Nrf2-mediated phase II enzymes and reduced PRS-induced oxidative damage in both male and female offspring. Moreover, PRS markedly decreased mRNA levels of various neuron markers, as well as resultant offspring cognitive function, based on spontaneous alternation performance and Morris water maze tests, the results of which were significantly improved by maternal Res supplementation. Our results provide evidence indicating that AMPK may modulate mitochondrial content and phase II enzymes in neuronal cells, a process which may play an essential role in preventing PRS-induced cognitive impairment. Through the coupling of mitochondrial biogenesis and the Nrf2 pathway, AMPK may modulate oxidative stress and be a promising target against neurological disorders.

Exposure to non-nutritive sweeteners during pregnancy and lactation: Impact in programming of metabolic diseases in the progeny later in life

The nutritional environment during embryonic, fetal and neonatal development plays a crucial role in the offspring's risk of developing diseases later in life. Although non-nutritive sweeteners (NNS) provide sweet taste without contributing to energy intake, animal studies showed that long-term consumption of NSS, particularly aspartame, starting during the perigestational period may predispose the offspring to develop obesity and metabolic syndrome later in life. In this paper, we review the impact of NNS exposure during the perigestational period on the long-term disease risk of the offspring, with a particular focus on metabolic diseases. Some mechanisms underlying NNS adverse metabolic effects have been proposed, such as an increase in intestinal glucose absorption, alterations in intestinal microbiota, induction of oxidative stress and a dysregulation of appetite and reward responses. The data reviewed herein suggest that NNS consumption by pregnant and lactating women should be looked with particular caution and requires further research.

Exercise-induced skeletal muscle remodeling and metabolic adaptation: redox signaling and role of autophagy

SIGNIFICANCE

Skeletal muscle is a highly plastic tissue. Exercise evokes signaling pathways that strongly modify myofiber metabolism and physiological and contractile properties of skeletal muscle. Regular physical activity is beneficial for health and is highly recommended for the prevention of several chronic conditions. In this review, we have focused our attention on the pathways that are known to mediate physical training-induced plasticity.

RECENT ADVANCES

An important role for redox signaling has recently been proposed in exercise-mediated muscle remodeling and peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) activation. Still more currently, autophagy has also been found to be involved in metabolic adaptation to exercise.

CRITICAL ISSUES

Both redox signaling and autophagy are processes with ambivalent effects; they can be detrimental and beneficial, depending on their delicate balance. As such, understanding their role in the chain of events induced by exercise and leading to skeletal muscle remodeling is a very complicated matter. Moreover, the study of the signaling induced by exercise is made even more difficult by the fact that exercise can be performed with several different modalities, with this having different repercussions on adaptation.

FUTURE DIRECTIONS

Unraveling the complexity of the molecular signaling triggered by exercise on skeletal muscle is crucial in order to define the therapeutic potentiality of physical training and to identify new pharmacological compounds that are able to reproduce some beneficial effects of exercise. In evaluating the effect of new "exercise mimetics," it will also be necessary to take into account the involvement of reactive oxygen species, reactive nitrogen species, and autophagy and their controversial effects.

Dietary supplementation with fish oil alters the expression levels of proteins governing mitochondrial dynamics and prevents high-fat diet-induced endothelial dysfunction

Diets supplemented with fish oil (FO), which is rich in n-3 PUFA, have been shown to modify several key risk factors for CVD. The purpose of the present study was to determine the effect of FO supplementation on mitochondrial dynamic protein expression in the endothelium and on endothelial cell function. Male apoE-deficient (apoE-/-) mice (8 weeks old, n 12 per group) were fed a high-fat diet containing 45% fat (HFD group) or a HFD with partial replacement of lard with 10% (w/w) FO (FO group) (total EPA and DHA content 64.1 g/kg) for 8 weeks. ApoE-/- mice in the FO group had a greater endothelium-dependent vasorelaxation response to acetylcholine (Ach) than those in the HFD group. The atherosclerotic lesion volume in the aortic sinus of mice in the FO group was 54% lower than that in the HFD group (P< 0.01). In addition, the aortas isolated from mice in the FO group had higher expression levels of Mfn2 and Opa1 but lower expression levels of Fis1 than those from the HFD group. Compared with mice fed the HFD, those fed the FO diet showed significantly lower levels of mitochondrial oxidative stress, cytochrome c release and caspase-3 activity (each P< 0.05). Furthermore, FO-fed mice displayed increased NO release and availability and enhanced endothelial NO synthase activity compared with HFD-fed mice. Taken together, these results reveal a novel mechanism by which FO protects against endothelial cell dysfunction, which may result in improved mitochondrial dynamics.

Long-term fish oil supplementation attenuates seizure activity in the amygdala induced by 3-mercaptopropionic acid in adult male rats

Several studies have provided evidence of significant effects of omega-3 fatty acids on brain functionality, including seizures and disorders such as epilepsy. Fish oil (FO) is a marine product rich in unsaturated omega-3 fatty acids. Considering that the amygdala is one of the brain structures most sensitive to seizure generation, we aimed to evaluate the effect of long-term chronic FO supplementation (from embryonic conception to adulthood) on the severity of seizures and amygdaloid electroencephalographic activity (EEG) in a 3-mercaptopropionic acid (3-MPA)-induced seizure model using adult rats. Female Wistar rats were fed a commercial diet supplemented daily with FO (300mg/kg) from puberty through mating, gestation, delivery, and weaning of the pups. Only the male pups were then fed daily with a commercial diet supplemented with the same treatment as the dam up to the age of 150days postpartum, when they were bilaterally implanted in the amygdala to record behavior and EEG activity before, during, and after seizures induced by administering 3-MPA. Results were compared with those obtained from rats supplemented with palm oil (PO) and rats treated with a vehicle (CTRL). The male rats treated with FO showed longer latency to seizure onset, fewer convulsive episodes, and attenuated severity compared those in the PO and CTRL groups according to the Racine scale. Moreover, long-term FO supplementation was associated with a reduction of the absolute power (AP) of the fast frequencies (12-25Hz) in the amygdala during the seizure periods. These findings support the idea that chronic supplementation with omega-3 of marine origin may have antiseizure properties as other studies have suggested.

Aerobic interval training attenuates mitochondrial dysfunction in rats post-myocardial infarction: roles of mitochondrial network dynamics

Aerobic interval training (AIT) can favorably affect cardiovascular diseases. However, the effects of AIT on post-myocardial infarction (MI)—associated mitochondrial dysfunctions remain unclear. In this study, we investigated the protective effects of AIT on myocardial mitochondria in post-MI rats by focusing on mitochondrial dynamics (fusion and fission). Mitochondrial respiratory functions (as measured by the respiratory control ratio (RCR) and the ratio of ADP to oxygen consumption (P/O)); complex activities; dynamic proteins (mitofusin (mfn) 1/2, type 1 optic atrophy (OPA1) and dynamin-related protein1 (DRP1)); nuclear peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α); and the oxidative signaling of extracellular signal-regulated kinase (ERK) 1/2, c-Jun NH₂-terminal protein kinase (JNK) and P53 were observed. Post-MI rats exhibited mitochondrial dysfunction and adverse mitochondrial network dynamics (reduced fusion and increased fission), which was associated with activated ERK1/2-JNK-P53 signaling and decreased nuclear PGC-1α. After AIT, MI-associated mitochondrial dysfunction was improved (elevated RCR and P/O and enhanced complex I, III and IV activities); in addition, increased fusion (mfn2 and OPA1), decreased fission (DRP1), elevated nuclear PGC-1α and inactivation of the ERK1/2-JNK-P53 signaling were observed. These data demonstrate that AIT may restore the post-MI mitochondrial function by inhibiting dynamics pathological remodeling, which may be associated with inactivation of ERK1/2-JNK-P53 signaling and increase in nuclear PGC-1α expression.

Maternal micronutrient imbalance alters gene expression of BDNF, NGF, TrkB and CREB in the offspring brain at an adult age

Micronutrients like folate, vitamin B12, and fatty acids which are interlinked in the one carbon cycle play a vital role in mediating epigenetic processes leading to an increased risk for neurodevelopmental disorders in the offspring. Our earlier study demonstrates that a micronutrient imbalanced diet adversely affects docosahexaenoic acid (DHA) and protein levels of neurotrophins like brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the brain and cognition in the offspring by 3 months of age. In this study we attempt to analyze if these effects are a consequence of a change in gene expression of these molecules. Further, we also examined the effect of either a postnatal control diet or a prenatal omega-3 fatty acid supplementation on gene expression in the cortex of the offspring. Pregnant rats were divided into control and five treatment groups at two levels of folic acid (normal and excess folate) in the presence and absence of vitamin B12. Omega-3 fatty acid (eicosapentaenoic acid - EPA+DHA) supplementation was given to vitamin B12 deficient groups. Following delivery, 8 dams from each group were shifted to control diet and remaining continued on the same treatment diet. Our results demonstrate that the imbalanced diet caused a marked reduction in the mRNA levels of BDNF, NGF, TrkB, and cAMP response element-binding protein (CREB). Prenatal omega-3 fatty acid supplementation to the maternal imbalanced diet was able to normalize the mRNA levels of all the above genes. This study demonstrates that a maternal diet imbalanced in micronutrients (folic acid, vitamin B12) influences gene expression of neurotrophins and their signalling molecules and thereby adversely affects the brain of the offspring.

Omega-3 fatty acid deficiency disrupts endocytosis, neuritogenesis, and mitochondrial protein pathways in the mouse hippocampus

Omega-3 fatty acid (n-3 FA) deficiency is an environmental risk factor for schizophrenia, yet characterization of the consequences of deficiency at the protein level in the brain is limited. We aimed to identify the protein pathways disrupted as a consequence of chronic n-3 deficiency in the hippocampus of mice. Fatty acid analysis of the hippocampus following chronic dietary deficiency revealed a 3-fold decrease (p < 0.001) in n-3 FA levels. Label free LC-MS/MS analysis identified and profiled 1008 proteins, of which 114 were observed to be differentially expressed between n-3 deficient and control groups (n = 8 per group). The cellular processes that were most implicated were neuritogenesis, endocytosis, and exocytosis, while specific protein pathways that were most significantly dysregulated were mitochondrial dysfunction and clathrin mediated endocytosis (CME). In order to characterize whether these processes and pathways are ones influenced by antipsychotic medication, we used LC-MS/MS to test the differential expression of these 114 proteins in the hippocampus of mice chronically treated with the antipsychotic agent haloperidol. We observed 23 of the 114 proteins to be differentially expressed, 17 of which were altered in the opposite direction to that observed following n-3 deficiency. Overall, our findings point to disturbed synaptic function, neuritogenesis, and mitochondrial function as a consequence of dietary deficiency in n-3 FA. This study greatly aids our understanding of the molecular mechanism by which n-3 deficiency impairs normal brain function, and provides clues as to how n-3 FA exert their therapeutic effect in early psychosis.

Perinatal supplementation with omega-3 polyunsaturated fatty acids improves sevoflurane-induced neurodegeneration and memory impairment in neonatal rats

Objectives

To investigate if perinatal Omega-3 polyunsaturated fatty acids (n-3 PUFAs) supplementation can improve sevoflurane-induced neurotoxicity and cognitive impairment in neonatal rats.

Methods

Female Sprague-Dawley rats (n = 3 each group) were treated with or without an n-3 PUFAs (fish oil) enriched diet from the second day of pregnancy to 14 days after parturition. The offspring rats (P7) were treated with six hours sevoflurane administration (one group without sevoflurane/prenatal n-3 PUFAs supplement as control). The 5-bromodeoxyuridine (Brdu) was injected intraperitoneally during and after sevoflurane anesthesia to assess dentate gyrus (DG) progenitor proliferation. Brain tissues were harvested and subjected to Western blot and immunohistochemistry respectively. Morris water maze spatial reference memory, fear conditioning, and Morris water maze memory consolidation were tested at P35, P63 and P70 (n = 9), respectively.

Results

Six hours 3% sevoflurane administration increased the cleaved caspase-3 in the thalamus, parietal cortex but not hippocampus of neonatal rat brain. Sevoflurane anesthesia also decreased the neuronal precursor proliferation of DG in rat hippocampus. However, perinatal n-3 PUFAs supplement could decrease the cleaved caspase-3 in the cerebral cortex of neonatal rats, and mitigate the decrease in neuronal proliferation in their hippocampus. In neurobehavioral studies, compared with control and n-3 PUFAs supplement groups, we did not find significant spatial cognitive deficit and early long-term memory impairment in sevoflurane anesthetized neonatal rats at their adulthood. However, sevoflurane could impair the immediate fear response and working memory and short-term memory. And n-3 PUFAs could improve neurocognitive function in later life after neonatal sevoflurane exposure.

Conclusion

Our study demonstrated that neonatal exposure to prolonged sevoflurane could impair the immediate fear response, working memory and short-term memory of rats at their adulthood, which may through inducing neuronal apoptosis and decreasing neurogenesis. However, these sevoflurane-induced unfavorable neuronal effects can be mitigated by perinatal n-3 PUFAs supplementation.

Autism as a disorder of deficiency of brain-derived neurotrophic factor and altered metabolism of polyunsaturated fatty acids

Autism has a strong genetic and environmental basis in which inflammatory markers and factors concerned with synapse formation, nerve transmission, and information processing such as brain-derived neurotrophic factor (BDNF), polyunsaturated fatty acids (PUFAs): arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic acids (DHA) and their products and neurotransmitters: dopamine, serotonin, acetylcholine, γ-aminobutyric acid, and catecholamines and cytokines are altered. Antioxidants, vitamins, minerals, and trace elements are needed for the normal metabolism of neurotrophic factors, eicosanoids, and neurotransmitters, supporting reports of their alterations in autism. But, the exact relationship among these factors and their interaction with genes and proteins concerned with brain development and growth is not clear. It is suggested that maternal infections and inflammation and adverse events during intrauterine growth of the fetus could lead to alterations in the gene expression profile and proteomics that results in dysfunction of the neuronal function and neurotransmitters, alteration(s) in the metabolism of PUFAs and their metabolites resulting in excess production of proinflammatory eicosanoids and cytokines and a deficiency of anti-inflammatory cytokines and bioactive lipids that ultimately results in the development of autism. Based on these evidences, it is proposed that selective delivery of BDNF and methods designed to augment the production of anti-inflammatory cytokines and eicosanoids and PUFAs may prevent, arrest, or reverse the autism disease process.

Fish oil provides robust and sustained memory recovery after cerebral ischemia: influence of treatment regimen

We previously reported that long-term treatment with fish oil (FO) facilitates memory recovery after transient, global cerebral ischemia (TGCI), despite the presence of severe hippocampal damage. The present study tested whether this antiamnesic effect resulted from an action of FO on behavioral performance itself, or whether it resulted from an anti-ischemic action. Different treatment regimens were used that were distinguished from each other by their initiation or duration with regard to the onset of TGCI and memory assessment. Naive rats were trained in an eight-arm radial maze, subjected to TGCI (4-VO model, 15 min), and tested for memory performance up to 6 weeks after TGCI. Fish oil (docosahexaenoic acid, 300 mg/kg/day) was given orally according to one of the following regimens: regimen 1 (from 3 days prior to ischemia until 4 weeks post-ischemia), regimen 2 (from 3 days prior to ischemia until 1 week post-ischemia), and regimen 3 (from week 2 to week 5 post-ischemia). When administered according to regimens 1 and 2, FO abolished amnesia completely. This effect persisted for at least 5 weeks after discontinuing the treatment. Such an effect did not occur, however, in the group treated according to regimen 3. Hippocampal and cortical damage was not alleviated by FO. The present results demonstrate that FO-mediated memory recovery (or preservation) following TGCI is a reproducible, robust, and long-lasting effect. Moreover, such an effect was found with a relatively short period of treatment, provided it covered the first days prior to and after ischemia. This suggests that FO prevented amnesia by changing some acute, ischemia/reperfusion-triggered process and not by stimulating memory performance on its own.

Concomitant docosahexaenoic acid administration ameliorates stress-induced cognitive impairment in rats

Long chain n-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may slow cognitive decline. DHA plays an important role in neural function and decreased plasma DHA are associated with cognitive decline in healthy elderly adults and in patients with Alzheimer's disease. In this study we tested a hypothesis that DHA protects cognitive functions of male Wistar rats against negative impact of prolonged restraint stress. Specifically, we attempted to characterize the preventive action of prolonged treatment with DHA enriched preparation (daily dose of DHA: 300mg/kg, p.o. for 21days) in comparison with positive control (fluoxetine: 10mg/kg daily, p.o. for 21days) against an impairment caused by chronic restraint stress (2h daily for 21days) on recognition memory tested in a object recognition task and on the spatial working memory tested in Morris water maze. We found that administration of DHA enriched preparation prevented deleterious effects of chronic restraint stress both on recognition (p<0.01) and on the working spatial memory (p<0.001).

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.

Maternal prenatal omega-3 fatty acid supplementation attenuates hyperoxia-induced apoptosis in the developing rat brain

Supraphysiologic amounts of oxygen negatively influences brain maturation and development. The aim of the present study was to evaluate whether maternal ω-3 long-chain polyunsaturated fatty acid (ω-3 FA) supplementation during pregnancy protects the developing brain against hyperoxic injury. Thirty-six rat pups from six different dams were divided into six groups according to the diet modifications and hyperoxia exposure. The groups were: a control group (standard diet+room air), a hyperoxia group (standard diet+80% O₂ exposure), a hyperoxia+high-dose ω-3 FA-supplemented group, a hyperoxia+low-dose ω-3 FA-supplemented group, a room air+low-dose ω-3 FA-supplemented+group, and a room air+high dose ω-3 FA-supplemented group. The ω-3 FA's were supplemented as a mixture of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) from the second day of pregnancy until birth. Rat pups in the hyperoxic groups were exposed to 80% oxygen from birth until postnatal day 5 (P5). At P5, all animals were sacrificed. Neuronal cell death and apoptosis were evaluated by cell count, TUNEL, and active Caspase-3 immunohistochemistry. Histopathological examination showed that maternally ω-3 FA deficient diet and postnatal hyperoxia exposure were associated with significantly lower neuronal counts and significantly higher apoptotic cell death in the selected brain regions. Ω-3 FA treatment significantly diminished apoptosis, in the selected brain regions, in a dose dependent manner. Our results suggest that the maternal ω-3 FA supply may protect the developing brain against hyperoxic injury.