Beneficial Effects Of Docosahexaenoic Acid Research Articles

Abstract 2119: Transcriptomic Profiling Reveals Therapeutic Potential Of Docosahexaenoic Acid For SARS Coronaviruses Infection Management

Prior work from our laboratory not only suggested that docosahexaenoic acid (DHA) may upregulate immune response pathways in human monocytes, it also revealed that DHA reduces angiotensin converting enzyme 2 (ACE2), the cellular receptor for SARS coronaviruses (SARS-CoV), in various rat tissues and human cultured cells. Also, DHA was found to inhibit cellular entry of SARS-CoV-2 pseudovirus. Thus, it was hypothesized that DHA has the potential to help manage SARS-CoV infection. RNA-seq was performed on DHA-treated (20 or 125 μM for 8 h) and control human EA.hy926 cells in both the growing and quiescent states. The data were processed by the RSEM-STAR-DESeq2 pipeline, and then subjected to gene set enrichment analysis (GSEA) with clusterProfiler. GSEA revealed that only in quiescent cells, 20 μM DHA downregulated pathways related to SARS-CoV-1/2-host interactions, specifically the processes by which the virus disrupts host protein translation and global mRNA splicing to suppress host defenses. The Reactome term “potential therapeutics for SARS” was positively enriched by both 20 and 125 μM DHA in quiescent cells only, including genes related to nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, interleukin-6 pathway, heat shock proteins, and TBK1 . However, in growing cells, terms related to SARS-CoV-1/2-host interactions were upregulated by DHA. Beyond derailing SARS-CoV via translation machinery and ACE2, DHA was also previously found to concomitantly reduce ACE1 protein levels, thus preserving the ACE1/ACE2 balance. This is significant because the balance of ACE1/ACE2 is important for maintaining renin-angiotensin system homeostasis, a factor critical in the pathogenesis of long COVID. Overall, our findings advance a novel perspective on the therapeutic potential of DHA for managing SARS-CoV infection, via its ability to hinder virus-host interactions. Moreover, the beneficial effects of DHA only occurred in quiescent (healthy) endothelial cells but not growing (dysfunctional) endothelial cells, implying that COVID-19 patients without CVD may be more responsive to DHA treatment compared to patients with underlying CVD. Further in vitro , in vivo , and even clinical studies are required to validate these effects of DHA on SARS-CoV.

DHA alleviated hepatic and adipose inflammation with increased adipocyte browning in high-fat diet-induced obese mice

Obesity is associated with accumulation of inflammatory immune cells in white adipose tissue, whereas thermogenic browning adipose tissue is inhibited. Dietary fatty acids are important nutritional components and several clinical and experimental studies have reported beneficial effects of docosahexaenoic acid (DHA) on obesity-related metabolic changes. In this study, we investigated effects of DHA on hepatic and adipose inflammation and adipocyte browning in high-fat diet-induced obese C57BL/6J mice, and in vitro 3T3-L1 preadipocyte differentiation. Since visceral white adipose tissue has a close link with metabolic abnormality, epididymal adipose tissue represents current target for evaluation. A course of 8-week DHA supplementation improved common phenotypes of obesity, including improvement of insulin resistance, inhibition of macrophage M1 polarization, and preservation of macrophage M2 polarization in hepatic and adipose tissues. Moreover, dysregulated adipokines and impaired thermogenic and browning molecules, considered obesogenic mechanisms, were improved by DHA, along with parallel alleviation of endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and mitochondrial DNA stress-directed innate immunity. During 3T3-L1 preadipocytes differentiation, DHA treatment decreased lipid droplet accumulation and increased the levels of thermogenic, browning, and mitochondrial biogenesis molecules. Our study provides experimental evidence that DHA mitigates obesity-associated inflammation and induces browning of adipose tissue in visceral epididymal adipose tissue. Since obesity is associated with metabolic abnormalities across tissues, our findings indicate that DHA may have potential as part of a dietary intervention to combat obesity.

DHA alleviates diet-induced skeletal muscle fiber remodeling via FTO/m6A/DDIT4/PGC1\u03b1 signaling

BackgroundObesity leads to a decline in the exercise capacity of skeletal muscle, thereby reducing mobility and promoting obesity-associated health risks. Dietary intervention has been shown to be an important measure to regulate skeletal muscle function, and previous studies have demonstrated the beneficial effects of docosahexaenoic acid (DHA; 22:6 ω-3) on skeletal muscle function. At the molecular level, DHA and its metabolites were shown to be extensively involved in regulating epigenetic modifications, including DNA methylation, histone modifications, and small non-coding microRNAs. However, whether and how epigenetic modification of mRNA such as N6-methyladenosine (m6A) mediates DHA regulation of skeletal muscle function remains unknown. Here, we analyze the regulatory effect of DHA on skeletal muscle function and explore the involvement of m6A mRNA modifications in mediating such regulation.ResultsDHA supplement prevented HFD-induced decline in exercise capacity and conversion of muscle fiber types from slow to fast in mice. DHA-treated myoblasts display increased mitochondrial biogenesis, while slow muscle fiber formation was promoted through DHA-induced expression of PGC1α. Further analysis of the associated molecular mechanism revealed that DHA enhanced expression of the fat mass and obesity-associated gene (FTO), leading to reduced m6A levels of DNA damage-induced transcript 4 (Ddit4). Ddit4 mRNA with lower m6A marks could not be recognized and bound by the cytoplasmic m6A reader YTH domain family 2 (YTHDF2), thereby blocking the decay of Ddit4 mRNA. Accumulated Ddit4 mRNA levels accelerated its protein translation, and the consequential increased DDIT4 protein abundance promoted the expression of PGC1α, which finally elevated mitochondria biogenesis and slow muscle fiber formation.ConclusionsDHA promotes mitochondrial biogenesis and skeletal muscle fiber remodeling via FTO/m6A/DDIT4/PGC1α signaling, protecting against obesity-induced decline in skeletal muscle function.

The Protective Effect of Docosahexaenoic Acid on PC12 Cells in Oxidative Stress Induced by H2O2 through the TrkB-Erk1/2-CREB Pathway

Docosahexaenoic acid (DHA) has attracted plenty of interest in the prevention of neurodegenerative diseases. Although the beneficial effects of DHA on the central nervous system function are recognized, more information on the molecular mechanisms involved in its neuroprotective effects is required. The present study aimed to evaluate the effects of DHA on the function of mitochondria, neurite growth-related proteins signaling pathway, and neural signal transmission. In this study, PC12 cells were treated with H2O2 (400 μM) to establish an oxidative damage model. Results showed that DHA improved the viability and morphology of PC12 cells. DHA significantly increased the antioxidant capacity, mitochondrial membrane potential, and activity of ATPase in the cells. Furthermore, the phosphorylation levels of tyrosine kinase receptor (BTrkB), phospholipase C-γ1 (PLCγ1), calcium/calmodulin-dependent protein kinase II (CaMKII), extracellular regulated protein kinases 1/2 (ERK1/2), and cAMP-response element-binding protein (CREB) were upregulated by DHA. The damage on F-actin induced by H2O2 was reversed by DHA, indicating that DHA could protect neurite outgrowth. In addition, DHA increased the content of acetylcholine and γ-aminobutyric acid while decreasing glutamic acid. These results revealed that DHA could protect PC12 cells from damage induced by H2O2 through the TrkB-ERK1/2-CREB pathway.

Omega-3 fatty acid-rich fish oil supplementation prevents rosiglitazone-induced osteopenia in aging C57BL/6 mice and in vitro studies

Rosiglitazone is an effective insulin-sensitizer, however associated with bone loss mainly due to increased bone resorption and bone marrow adiposity. We investigated the effect of the co-administration of fish oil rich in omega-3 fatty acids (FAs) on rosiglitazone-induced bone loss in C57BL/6 mice and the mechanisms underlying potential preventive effect. Mice fed the iso-caloric diet supplemented with fish oil exhibited significantly higher levels of bone density in different regions compared to the other groups. In the same cohort of mice, reduced activity of COX-2, enhanced activity of alkaline phosphatase, lower levels of cathepsin k, PPAR-γ, and pro-inflammatory cytokines, and a higher level of anti-inflammatory cytokines were observed. Moreover, fish oil restored rosiglitazone-induced down-regulation of osteoblast differentiation and up-regulation of adipocyte differentiation in C3H10T1/2 cells and inhibited the up-regulation of osteoclast differentiation of RANKL-treated RAW264.7 cells. We finally tested our hypothesis on human Mesenchymal Stromal Cells differentiated to osteocytes and adipocytes confirming the beneficial effect of docosahexaenoic acid (DHA) omega-3 FA during treatment with rosiglitazone, through the down-regulation of adipogenic genes, such as adipsin and FABP4 along the PPARγ/FABP4 axis, and reducing the capability of osteocytes to switch toward adipogenesis. Fish oil may prevent rosiglitazone-induced bone loss by inhibiting inflammation, osteoclastogenesis, and adipogenesis and by enhancing osteogenesis in the bone microenvironment.

Protective effects of docosahexaenoic acid against non-alcoholic hepatic steatosis through activating of JAK2/STAT3 signaling pathway

Non-alcoholic fatty liver disease is the most common cause of hepatic dysfunction. In the present study, human normal hepatocyte L02 cells were treated with 50% fetal bovine serum to induce the formation of hepatic steatosis in vitro, and then the cells were treated with docosahexaenoic acid to investigate its protective effect on Non-alcoholic fatty liver disease. Our results showed that 50% of fetal bovine serum significantly induced intracellular lipid accumulation and hepatocyte fatty degeneration within 48 h. The expression level of adipose formation-related genes was significantly up-regulated, such as PPARγ, C/EBPα and SREBP-1; meanwhile, the content of cellular total lipid, total cholesterol and triglycerides were significantly increased after 50% fetal bovine serum treatment. Interestingly, docosahexaenoic acid treatment could inhibit FBS-induced intracellular lipid accumulation in L02 cells and the expression of lipogenic genes. Moreover, docosahexaenoic acid treatment could reduce hepatic steatosis-induced oxidative stress and endoplasmic reticulum stress response, and these responses were shown by the modification of antioxidant enzyme activities and GRP78, CHOP expression. In addition, the results showed that docosahexaenoic acid can activate the JAK2/STAT3 signaling pathway in fatty liver L02 cell; inhibition of JAK2/STAT3 signaling pathway by WP1066 abolished the beneficial effects of docosahexaenoic acid on hepatic steatosis accompanied with the increased expression of lipogenic genes and endoplasmic reticulum stress response. Above all, the present study showed that docosahexaenoic acid can alleviate non-alcoholic hepatic steatosis by activating JAK2/STAT3 signaling pathway.

Synergistic Beneficial Effect of Docosahexaenoic Acid (DHA) and Docetaxel on the Expression Level of Matrix Metalloproteinase-2 (MMP-2) and MicroRNA-106b in Gastric Cancer.

Gastric cancer (GC) is one of the most common cancers with the majority of patients recognized in advanced stages. Theefficacy of using docosahexaenoic acid (DHA) asa supplementary agent has been suggested in treatment along with chemotherapeutics including docetaxel. However, themolecular signatures of such beneficial effects are not well-understood. We aimed to evaluate the effects of DHA and docetaxel on the expression level of metastasis-related genes, including MMP-2 and talin-2, and their controlling miRNAs, miR-106b and miR-194, in metastatic GC cell line, MKN45. GC cell line, MKN45, was cultured, and determination of IC50 of DHA was done by MTT test. Cells were treated with docetaxel, DHA, and their combination for 24h, and then total RNA was extracted and cDNA synthesis was done using standard protocols. The expression level of target genes, MMP-2 and talin-2, and miR-106b and miR-194 were determined by using quantitative real-time PCR. The expression level of MMP-2 was decreased significantly in all treated cells. However, talin-2 showed significant downregulation only after treatment with docetaxel. In contrary to increased expression after treatment with docetaxel, DHA led to a significant under-expression of miR-106b. Thesimilar effect was seen for miR-194. Combination of docetaxel and DHA led to the significant downregulation of MMP-2. Also, DHA lowered the docetaxel-mediated upregulation of miR-106b oncomiR. In conclusion, supplementation of docetaxel therapy with DHA in GC patients would be considered asa beneficial approach in cancer treatment.

DHA blocks TPA-induced cell invasion by inhibiting MMP-9 expression via suppression of the PPAR-γ/NF-κB pathway in MCF-7 cells

Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is considered to have applications in cancer prevention and treatment. The beneficial effects of DHA against cancer metastasis are well established; however, the mechanisms underlying these effects in breast cancer are not clear. Cell invasion is critical for neoplastic metastasis, and involves the degradation of the extracellular matrix by matrix metalloproteinase (MMP)-9. The present study investigated the inhibitory effect of DHA on MMP-9 expression and cell invasion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the MCF-7 breast cancer cell line. DHA inhibited the TPA-induced activation of mitogen-activated protein kinase (MAPK) and the transcription of nuclear factor (NF)-κB, but did not inhibit the transcription of activator protein-1. DHA increased the activity of peroxisome proliferator-activated receptor (PPAR)-γ, an effect that was reversed by the application of the PPAR-γ antagonist GW9662. In addition, combined treatment with GW9662 and DHA increased NF-κB-related protein expression. These results indicate that DHA regulates MMP-9 expression and cell invasion via modulation of the MAPK signaling pathway and PPAR-γ/NF-κB activity. This suggests that DHA could be a potential therapeutic agent for the prevention of breast cancer metastasis.

Docosahexaenoic acid inhibits Helicobacter pylori-induced STAT3 phosphorylation through activation of PPARγ.

The health beneficial effects of docosahexaenoic acid (DHA) have been attributed to its anti-inflammatory properties. However, the molecular mechanism underlying anti-inflammatory effects of DHA remains largely elusive. In the present study, DHA was found to suppress the phosphorylation and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) induced by Helicobacter pylori infection in human gastric cancer AGS cells. Notably, DHA induced expression of suppressor of cytokine signaling 3 (SOCS3), a negative regulator of STAT3. Knockdown of SOCS3 abolished the suppressive effect of DHA on STAT3(Tyr705) phosphorylation induced by H. pylori infection. DHA also induced nuclear translocation, DNA binding, and transcriptional activities of peroxisome proliferator-activated receptor gamma (PPARγ) in AGS cells. Knockdown of PPARγ inhibited the transcription of SOCS3 and attenuated the suppressive effect of DHA on phosphorylation of STAT3(Tyr705) induced by H. pylori. The PPARγ antagonist bisphenol A diglycidyl ether also mitigated the suppressive effect of DHA on H. pylori-induced phosphorylation of STAT3(Tyr705) . In addition, DHA inhibited the expression of c-Myc, which was attenuated in the AGS cells harboring SOCS3 specific siRNA. DHA also markedly decreased anchorage-independent growth of AGS cells infected by H. pylori. DHA inhibits H. pylori-induced STAT3 phosphorylation in a PPARγ/SOCS3-dependent manner.

The Impact of Docosahexaenoic Acid on Alzheimer's Disease: Is There a Role of the Blood-Brain Barrier?

There currently is no cure or established preventative treatment for Alzheimer's disease (AD). Considering the increasing aging population and the subsequent high prevalence of AD worldwide, identifying a cost-effective way to prevent AD is an essential unmet medical need. Relative to healthy human brain samples, postmortem AD brain samples have been shown to exhibit lower docosahexaenoic acid (DHA) levels, an essential polyunsaturated fatty acid required for normal neuronal function. However, findings from different studies are controversial and it is not clear whether this alteration in DHA brain levels is a cause or consequence of AD. Animal studies have also demonstrated that administration of DHA can alleviate the underlying pathophysiology of AD, including but not limited to amyloid pathology, tau pathology, and neuroinflammation. Moreover, DHA has been suggested to exert cognitive-enhancing effects and epidemiological studies have suggested that regular consumption of fish or omega-3 fatty acid enriched diets can attenuate the cognitive decline in AD and/or lower the risk of developing AD. However, the beneficial effects of DHA in AD have not been clearly demonstrated by current human randomised-control trials. In addition, the underlying reasons for the lower brain levels of DHA in AD remain to be fully characterised. However, given that the brain has limited capacity to produce DHA de novo and obtains DHA from the plasma, one plausible explanation for the lower brain levels of DHA in AD is reduced bloodbrain barrier (BBB) transport of this fatty acid in AD, as has been reported in one mouse model of AD. Unfortunately, the actual mechanisms governing the BBB transport of DHA in healthy conditions are not clearly understood, complicating the relationship between reduced BBB transport of DHA, attenuated DHA brain levels and AD pathology. The purpose of this review, therefore, is to summarise the findings of the biochemical, functional and epidemiological studies assessing the impact of DHA on the progression of AD, with a focus on how brain DHA levels alter in AD, the mechanisms thought to be held responsible for the apparent protective effects of DHA in AD, and the factors governing BBB transport of DHA in AD.

Docosahexaenoic Acid Alleviates Atopic Dermatitis by Generating Tregs and IL-10/TGF-β-Modified Macrophages via a TGF-β-Dependent Mechanism

Regulatory T cells (Tregs) have key roles in the immune response by suppressing the differentiation and proliferation of various immune cells. The beneficial effects of docosahexaenoic acid (DHA) have been described for many diseases; however, the mechanism by which it modulates the immune system is poorly understood. Therefore, the aim of this study was to examine whether DHA suppresses allergic reactions and upregulates the generation of CD4(+)Foxp3(+) T cells. We also examined the effects of transfusing interleukin-10/transforming growth factor-β (TGF-β)-modified macrophages (M2 macrophages) treated with DHA into a mouse model of atopic dermatitis. Here, we show that administration of DHA upregulates the generation of TGF-β-dependent CD4(+) forkhead box protein 3 (Foxp3(+)) Tregs. DHA induced T-cell hypo-responsiveness and downregulated cytokines associated with T helper (Th)-1, Th2, and Th17 cells. The differentiation of Foxp3(+) Tregs into CD4(+) T cells was directly mediated by DHA-M2 macrophages, which deactivated effector macrophages and inhibited CD4(+) T-cell proliferation. DHA showed therapeutic effects in mice with experimental atopic dermatitis. These results show that DHA enhances the function of M2 macrophages and that the generation of Tregs effectively protects mice against an inflammatory immune disorder. Thus, DHA may be a useful therapeutic strategy for treating chronic inflammatory diseases.

Purine receptors are required for DHA-mediated neuroprotection against oxygen and glucose deprivation in hippocampal slices.

Docosahexaenoic acid (DHA) is important for central nervous system function during pathological states such as ischemia. DHA reduces neuronal injury in experimental brain ischemia; however, the underlying mechanisms are not well understood. In the present study, we investigated the effects of DHA on acute hippocampal slices subjected to experimental ischemia by transient oxygen and glucose deprivation (OGD) and re-oxygenation and the possible involvement of purinergic receptors as the mechanism underlying DHA-mediated neuroprotection. We observed that cellular viability reduction induced by experimental ischemia as well as cell damage and thiobarbituric acid reactive substances (TBARS) production induced by glutamate (10 mM) were prevented by hippocampal slices pretreated with DHA (5 μM). However, glutamate uptake reduction induced by OGD and re-oxygenation was not prevented by DHA. The beneficial effect of DHA against cellular viability reduction induced by OGD and re-oxygenation was blocked with PPADS (3 μM), a nonselective P2X1-5 receptor antagonist as well as with a combination of TNP-APT (100 nM) plus brilliant blue (100 nM), which blocked P2X1, P2X3, P2X2/3, and P2X7 receptors, respectively. Moreover, adenosine receptors blockade with A1 receptor antagonist DPCPX (100 nM) or with A2B receptor antagonist alloxazine (100 nM) inhibited DHA-mediated neuroprotection. The addition of an A2A receptor antagonist ZM241385 (50 nM), or A3 receptor antagonist VUF5574 (1 μM) was ineffective. Taken together, our results indicated that neuroprotective actions of DHA may depend on P2X, A1, and A2B purinergic receptors activation. Our results reinforce the notion that dietary DHA may act as a local purinergic modulator in order to prevent neurodegenerative diseases.

70: The generation of Tregs and IL-10/TGF-β-modified macrophages by docosahexaenoic acid via TGF-β dependent mechanism suppresses atopic dermatitis

Regulatory T cells (Tregs) play key roles in the immune response by suppressing the differentiation and proliferation of various immune cells. The beneficial effects of docosahexaenoic acid (DHA) have been described for many diseases; however, the mechanism by which it modulates immune system is poorly understood. Therefore, the aim of this study was to examine whether DHA suppresses allergic reactions and up-regulates the generation of CD4 + Foxp3 + T cells. We also examined the effects of transfusing IL-10/TGF- β -modified macrophages (M2 macrophages) treated with DHA into a mouse model of atopic dermatitis. Here, we show that administration of DHA up-regulates the generation of TGF- β -dependent CD4 + Foxp3 + Tregs. DHA induced T cell hypo-responsiveness and down-regulated cytokines associated with T helper (Th)-1, Th2, and Th17 cells. The differentiation of Foxp3 + Tregs into CD4 + T cells was directly mediated by DHA-M2 macrophages, which deactivated effector macrophages and inhibited CD4 + T cell proliferation. DHA showed therapeutic effects in mice with experimental atopic dermatitis. These results show that DHA enhances the function of M2 macrophages, and that the generation of Tregs effectively protects mice against an inflammatory immune disorder. Thus, DHA may be a useful therapeutic strategy for treating chronic inflammatory diseases. This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2013R1A1A2012465 ).

Docosahexaenoic Acid Modulates the Enterocyte Caco-2 Cell Expression of MicroRNAs Involved in Lipid Metabolism1–3

Consumption of the long-chain ω-3 (n–3) polyunsaturated fatty acid docosahexaenoic acid (DHA) is associated with a reduced risk of cardiovascular disease and greater chemoprevention. However, the mechanisms underlying the biologic effects of DHA remain unknown. It is well known that microRNAs (miRNAs) are versatile regulators of gene expression. Therefore, we aimed to determine if the beneficial effects of DHA may be modulated in part through miRNAs. Loss of dicer 1 ribonuclease type III (DICER) in enterocyte Caco-2 cells supplemented with DHA suggested that several lipid metabolism genes are modulated by miRNAs. Analysis of miRNAs predicted to target these genes revealed several miRNA candidates that are differentially modulated by fatty acids. Among the miRNAs modulated by DHA were miR-192 and miR-30c. Overexpression of either miR-192 or miR-30c in enterocyte and hepatocyte cells suggested an effect on the expression of genes related to lipid metabolism, some of which were confirmed by endogenous inhibition of these miRNAs. Our results show in enterocytes that DHA exerts its biologic effect in part by regulating genes involved in lipid metabolism and cancer. Moreover, this response is mediated through miRNA activity. We validate novel targets of miR-30c and miR-192 related to lipid metabolism and cancer including nuclear receptor corepressor 2, isocitrate dehydrogenase 1, DICER, caveolin 1, ATP-binding cassette subfamily G (white) member 4, retinoic acid receptor β, and others. We also present evidence that in enterocytes DHA modulates the expression of regulatory factor X6 through these miRNAs. Alteration of miRNA levels by dietary components in support of their pharmacologic modulation might be valuable in adjunct therapy for dyslipidemia and other related diseases.

Progressive Retinal Degeneration and Glial Activation in the CLN6nclf Mouse Model of Neuronal Ceroid Lipofuscinosis: A Beneficial Effect of DHA and Curcumin Supplementation

Neuronal ceroid lipofuscinosis (NCL) is a group of neurodegenerative lysosomal storage disorders characterized by vision loss, mental and motor deficits, and spontaneous seizures. Neuropathological analyses of autopsy material from NCL patients and animal models revealed brain atrophy closely associated with glial activity. Earlier reports also noticed loss of retinal cells and reactive gliosis in some forms of NCL. To study this phenomenon in detail, we analyzed the ocular phenotype of CLN6nclf mice, an established mouse model for variant-late infantile NCL. Retinal morphometry, immunohistochemistry, optokinetic tracking, electroretinography, and mRNA expression were used to characterize retinal morphology and function as well as the responses of Müller cells and microglia. Our histological data showed a severe and progressive degeneration in the CLN6nclf retina co-inciding with reactive Müller glia. Furthermore, a prominent phenotypic transformation of ramified microglia to phagocytic, bloated, and mislocalized microglial cells was identified in CLN6nclf retinas. These events overlapped with a rapid loss of visual perception and retinal function. Based on the strong microglia reactivity we hypothesized that dietary supplementation with immuno-regulatory compounds, curcumin and docosahexaenoic acid (DHA), could ameliorate microgliosis and reduce retinal degeneration. Our analyses showed that treatment of three-week-old CLN6nclf mice with either 5% DHA or 0.6% curcumin for 30 weeks resulted in a reduced number of amoeboid reactive microglia and partially improved retinal function. DHA-treatment also improved the morphology of CLN6nclf retinas with a preserved thickness of the photoreceptor layer in most regions of the retina. Our results suggest that microglial reactivity closely accompanies disease progression in the CLN6nclf retina and both processes can be attenuated with dietary supplemented immuno-modulating compounds.

Omega 3 fatty acids on child growth, visual acuity and neurodevelopment

The aim of this review is to evaluate the effects of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) supplementation in pregnant and lactating women and infants during postnatal life, on the visual acuity, psychomotor development, mental performance and growth of infants and children. Eighteen publications (11 sets of randomized control clinical trial [RCTs]) assessed the effects of the n-3 LCPUFA supplementation during pregnancy on neurodevelopment and growth, in the same subjects at different time points; 4 publications (2 data sets from RCTs) addressed physiological responses to n-3 LCPUFA supplementation during pregnancy & lactation and 5 publications (3 data sets from RCTs) exclusively during lactation. Some of these studies showed beneficial effects of docosahexaenoic acid (DHA) supplementation during pregnancy and/or lactation especially on visual acuity outcomes and some on long-term neurodevelopment; a few, showed positive effects on growth. There were also 15 RCTs involving term infants who received infant formula supplemented with DHA, which met our selection criteria. Many of these studies claimed a beneficial effect of such supplementation on visual, neural, or developmental outcomes and no effects on growth. Although new well designed and conducted studies are being published, evidence from RCTs does not demonstrate still a clear and consistent benefit of n-3 LCPUFA supplementation during pregnancy and/or lactation on term infants growth, neurodevelopment and visual acuity. These results should be interpreted with caution due to methodological limitations of the included studies.

Beneficial effect of docosahexaenoic acid on cholestatic liver injury in rats

Bile duct obstruction and subsequent cholestasis are associated with hepatocellular injury, cholangiocyte proliferation, stellate cell activation, Kupffer cell activation, oxidative stress, inflammation and fibrosis. Docosahexaenoic acid (DHA) is an essential polyunsaturated fatty acid that has been shown to possess health beneficial effects, including hepatoprotection. However, the molecular mechanism of DHA-mediated hepatoprotection is not fully understood. In the present study, we report the protective effect of DHA on cholestatic liver injury. Cholestasis was produced by bile duct ligation (BDL) in male Sprague–Dawley rats for 3 weeks. Daily administration of DHA was started 2 weeks before injury and lasted for 5 weeks. In comparison with the control group, the BDL group showed hepatic damage as evidenced by histological changes and elevation in serum biochemicals, ductular reaction, fibrosis, inflammation and oxidative stress. These pathophysiological changes were attenuated by chronic DHA supplementation. DHA alleviated BDL-induced transforming growth factor beta-1 (TGF-β1), intereukin-1beta, connective tissue growth factor and collagen expression. The anti-fibrotic effect of DHA was accompanied by reductions in α-smooth muscle actin-positive matrix-producing cells and Smad 2/3 activity critical to the fibrogenic potential of TGF-β1. DHA also attenuated BDL-induced leukocyte accumulation and nuclear factor-κB (NF-κB) activation. Further studies demonstrated an inhibitory effect of DHA on redox-sensitive intracellular signaling molecule extracellular signal-regulated kinase (ERK). Taken together, the hepatoprotective, anti-inflammatory and anti-fibrotic effects of DHA seem to be multifactorial. The beneficial effects of chronic DHA supplementation are associated with anti-oxidative and anti-inflammatory potential as well as down-regulation of NF-κB and transforming growth factor beta/Smad signaling probably via interference with ERK activation.

Neuroprotective and Ameliorative Actions of Polyunsaturated Fatty Acids Against Neuronal Diseases: Beneficial Effect of Docosahexaenoic Acid on Cognitive Decline in Alzheimer’s Disease

Docosahexaenoic acid (DHA, C22:6 n-3), the most abundant n-3 polyunsaturated fatty acid in the brain, is essential for brain growth and development. Recent evidence has indicated the potential health benefits of DHA for managing Alzheimer's disease (AD). For example, dietary administration of DHA considerably protects against and ameliorates the impairment of learning ability in amyloid-beta (Aβ)(1-40)-infused AD-model rats, with concurrent increases in DHA levels and decreases in the levels of lipid peroxide and reactive oxygen species in the cortico-hippocampal tissues. In addition, dietary DHA helps in eliminating the amyloid burden from the brains of AD-model rats. In vitro studies have revealed that DHA substantially inhibits Aβ fibrillation. Furthermore, DHA reduces amyloid-induced toxicity in cell culture. These in vitro data support the hypothesis that DHA can ameliorate the cognitive deficits of AD in vivo by limiting Aβ polymerization in the brains. Therefore, it might be a useful therapeutic agent to prevent and/or delay cognitive impairment in mild cases of AD.

Docosahexaenoic acid prevents dendritic cell maturation, inhibits antigen-specific Th1/Th17 differentiation and suppresses experimental autoimmune encephalomyelitis

Docosahexaenoic acid (DHA), the most abundant essential n − 3 polyunsaturated fatty acid in the CNS, emerged recently together with eicosapentaenoic acid (EPA) and DHA/EPA metabolic derivatives as a major player in the resolution of inflammation. Protective anti-inflammatory effects of DHA were reported in clinical studies and animal models of colitis, sepsis, and stroke. Here we report for the first time a beneficial effect of dietary n − 3 fatty acids in experimental autoimmune encephalomyelitis (EAE), a model for human multiple sclerosis. In the present study we investigated the effects of DHA on the function of bone marrow-derived dendritic cells (DC) in CD4 + T cell stimulation and differentiation. Pretreatment of DC with DHA prevented LPS-induced DC maturation, maintaining an immature phenotype characterized by low expression of costimulatory molecules and lack of proinflammatory cytokine production (IL-12p70, IL-6, and IL-23). DHA-treated DC were poor stimulators of antigen-specific T cells in terms of proliferation and Th1/Th17 differentiation. This was associated with an increase in p27(kip1), a cell cycle arresting agent, and with decreases in Tbet, GATA-3, and RORγt, master transcription factors for Th1, Th2, and Th17. In contrast, T cells co-cultured with DC-DHA express higher levels of TGFβ and Foxp3, without exhibiting a functional Treg phenotype. Similar to the in vitro results, the beneficial effect of DHA in EAE was associated with reduced numbers of IFNγ- and IL-17-producing CD4 + T cells in both spleen and CNS.

Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline

Background Docosahexaenoic acid (DHA) plays an important role in neural function. Decreases in plasma DHA are associated with cognitive decline in healthy elderly adults and in patients with Alzheimer's disease. Higher DHA intake is inversely correlated with relative risk of Alzheimer's disease. The potential benefits of DHA supplementation in age-related cognitive decline (ARCD) have not been fully examined. Objective Determine effects of DHA administration on improving cognitive functions in healthy older adults with ARCD. Methods Randomized, double-blind, placebo-controlled, clinical study was conducted at 19 U.S. clinical sites. A total of 485 healthy subjects, aged ≥55 with Mini-Mental State Examination >26 and a Logical Memory (Wechsler Memory Scale III) baseline score ≥1 standard deviation below younger adults, were randomly assigned to 900 mg/d of DHA orally or matching placebo for 24 weeks. The primary outcome was the CANTAB Paired Associate Learning (PAL), a visuospatial learning and episodic memory test. Results Intention-to-treat analysis demonstrated significantly fewer PAL six pattern errors with DHA versus placebo at 24 weeks (difference score, −1.63 ± 0.76 [−3.1, −0.14, 95% CI], P = .03). DHA supplementation was also associated with improved immediate and delayed Verbal Recognition Memory scores ( P < .02), but not working memory or executive function tests. Plasma DHA levels doubled and correlated with improved PAL scores ( P < .02) in the DHA group. DHA was well tolerated with no reported treatment-related serious adverse events. Conclusions Twenty-four week supplementation with 900 mg/d DHA improved learning and memory function in ARCD and is a beneficial supplement that supports cognitive health with aging. Trial Registration Clinicaltrials.gov, Identifier: NCT0027813.