Protective Effects Of Docosahexaenoic Acid Research Articles

Docosahexaenoic Acid Supplementation for Neonatal Hyperbilirubinemia: A Double-Blind, Randomized Clinical Trial.

Docosahexaenoic acid (DHA) is an essential component for brain development during fetal and early postnatal life. Hyperbilirubinemia is characterized by abnormally high levels of bilirubin in the bloodstream, frequently leading to jaundice in newborns. In severe instances, this condition can progress to neurological damage or kernicterus, a form of brain damage. Initial cell-based experiments conducted by our research team revealed that DHA significantly enhances the survival rate of nerve cells treated with bilirubin and diminishes the oxidative stress indicated by reduced peroxide activity caused by unconjugated bilirubin (UCB). Further investigations through animal studies demonstrated that DHA effectively mitigates bilirubin-induced brain injury in neonatal rats. However, the potential of DHA to decrease the incidence of bilirubin-induced brain damage in clinical settings has not been previously explored or reported. Infants with neonatal hyperbilirubinemia (n = 30 per group) participated in a double-blind, randomized, placebo-controlled parallel study. They received either 100 mg/d DHA or placebo syrup immediately when they were diagnosed. The study found that the bilirubin level at 48 hours of treatment, serum neuron-specific enolase (NSE) levels, mean phototherapy duration, and abnormal rate of cranial magnetic resonance imaging (MRI) were lower in the DHA group than those in the control group (P < .05). These results suggested that DHA is effective as an adjuvant treatment for hyperbilirubinemia in children. It can reduce the incidence of neonatal hyperbilirubinemia brain injury and plays a certain protective role. Clinical study on protective effect of DHA on neonatal bilirubin injury is registered at Chinese Clinical Trial Registry as ChiCTR2300070250.

Docosahexaenoic acid promotes M2 microglia phenotype via activating PPARγ-mediated ERK/AKT pathway against cerebral ischemia-reperfusion injury

In ischemia-reperfusion stroke, microglia play a dual role in brain injury as well as brain repair, and promoting their switch from a pro-inflammatory M1 phenotype to an anti-inflammatory M2 phenotype is considered to be a potential therapeutic strategy. Docosahexaenoic acid (DHA) is an essential long-chain omega-3 polyunsaturated fatty acid that exhibits potent anti-inflammatory properties in the acute phase of ischemic stroke, but its effect on microglia polarization is unknown. Thus, the objective of this study was to investigate the neuroprotective effects of DHA on rat brain following ischemia-reperfusion injury, and to investigate the mechanism by which DHA regulates microglia polarization. We administered DHA 5 mg/kg intraperitoneally daily for 3 d following a transient middle cerebral artery occlusion reperfusion model in rats. The protective effects of DHA on cerebral ischemia-reperfusion injury were detected by TTC staining, HE staining, Nissler staining, and TUNEL staining. Quantitative real-time PCR, immunofluorescence, western blot, and enzyme-linked immunosorbent assay were used to detect the expression of M1 and M2 microglia-associated markers and PPARγ-mediated ERK/AKT signaling pathway proteins. We found that DHA significantly improved brain injury by decreasing the expression of the M1 phenotypic marker (iNOS, CD16) and increasing the expression of the M2 phenotypic marker (Arg-1, CD206). DHA also increased the expression of peroxisome proliferator-activated receptor gamma (PPARγ) mRNA and protein, increased the expression of the pathway protein AKT, and decreased the expression of ERK1/2. In addition, DHA promoted the expression of anti-inflammatory factor IL-10 and decreased the expression of pro-inflammatory factors TNF-α and IL-1β. However, the PPARγ antagonist GW9662 greatly blocked these beneficial effects. These results suggest that DHA may activate PPARγ to inhibit ERK and activate AKT signaling pathways to regulate microglia polarization, thereby reducing neuroinflammation and promoting neurological recovery to alleviate cerebral ischemia-reperfusion injury.

Docosahexaenoic Acid and Tualang Honey Improve Brain Oxidative Status in Chronic Stress Rat Model

The main objective of this study was to investigate the protective effects of docosahexaenoic acid (DHA) and Tualang honey (TH) and their combination on several parameters of oxidative stress of the brain following exposure to chronic stress. Five groups of male Sprague Dawley rats ( 10 animal per group) were allocated in which Group 1 received normal saline and used as control; Group 2 was exposed to stress and received normal saline; Group 3 was exposed to stress and reviewed DHA (450 mg/kg body weight BD); Group 4 was exposed to stress and received TH (1 g/kg body weight BD), and Group 5 was exposed to stress and received combination of DHA and TH. Animals were exposed to chronic stress from 9 am to 2 pm daily for 4 weeks. The following oxidative parameters were measured: total antioxidant status (TAS) , glutathione, thiobarbituric acid reactive substances (TBARS) and protein carbonyl. The results showed that DHA, TH and their combination significantly reduced (p&lt;0.05) stress-induced elevation of corticosterone and TBARS levels and concurrently caused a significantly increased (p&lt;0.05) in TAS level. With regard to glutathione and protein carbonyl, only TH and combination of DHA+TH significantly reduced (p&lt;0.05) the oxidised glutathione and protein carbonyl. In all parameters, there was no significant difference between Group 5 in comparison to Group 3 and Group 4 indicating combination of DHA and TH was not superior to consuming DHA and TH alone. In conclusion, TH and to lesser extent DHA may protect the brain against oxidative stress induced by exposure to chronic stress but consuming these substances together does not give synergistic effect.&#x0D; Keywords: Oxidative stress, Honey, Docosahexaenoic acid, Chronic stress, Brain

The protective effect of docosahexaenoic acid on the stomach in Parkinson’s disease induced by MPTP in male C57BL/6 mice

The purpose of this study was to detect gastric changes in Parkinson’s disease induced by 1-methyl-4-phenyl-1.2.3.6.-tetrahydropyridine (MPTP), and to investigate the protective effect of docosahexaenoic acid (DHA) against these changes in mice. The mice were divided into 4 groups (n=10 in per group) as control, DHA, Parkinson and DHA+Parkinson groups. DHA was administered by gavage for 30 days. On the 23rd day of gavage treatment, the animals of the Parkinson and DHA+Parkinson groups were intraperitoneally injected with MPTP. Seven days after the injection of MPTP, their locomotor activity, bradykinesia and rotarod performance were measured. Tyrosine hydroxylase expression in substantia nigra and the apoptotic index, the concentrations of tumor necrosis factor-α and histamine, and the number of mast cells in the stomach were evaluated. Administration of DHA significantly prevented the reduction in motor functions (P&lt;0.001) and nigral TH neurons (P&lt;0.05), and apoptosis (P&lt;0.05), and an increase in TNF-α concentration (P&lt;0.01) in the stomach. An increase in the number of mast cells in the stomach wall was observed in PD (P&lt;0.001). DHA prevented the increase in the number of mast cells (P&lt;0.05) and the histamine level (P&lt;0.01) due to PD. As a result, MPTP administration in mice caused changes in the stomach as well as impairment in motor functions, and DHA was observed to reduce these changes.

Protective Effect of Docosahexaenoic Acid on Silica Nanoparticles Induced Biochemical Alterations in Rat Testes

Human health effects associated with silica exposure have been widely discussed. Environmental and occupational exposure to silica nanoparticles (SiNPs) is inevitable, as nanomaterials have become part of our daily routine. SiNPs were found to have severe toxicity than silica micro-particles in male reproductive systems. It might be due to the factor that smaller the diameter of silica nanoparticles, the greater will be the toxicity. In the present study, 40 and 80 mg SiNPs were exposed to rats for 60 days and a group treated with docosahexaenoic acid (DHA) along with SiNPs. At the end of the exposure, rats were sacrificed by anaesthetic overdose, rat testes were removed for the biochemical investigations namely, lipid peroxide levels (LPO), protein carbonyl content (PC), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione (GSH). Results of the present study demonstrates that SiNPs intoxicated rats were found increased LPO and PC level while the antioxidant level namely SOD, CAT, GPx and GSH were found to be decreased in the testes when compared with the control rats, while DHA acclimation rats were observed insignificant changes as compared with the SiNPs treated groups. On the basis of results it may be concluded that the oxidative stress markers increased in the intoxicated rats and the DHA supplementation might have rescued the SiNPs exposure.

Associations between plasma fatty acid concentrations and schizophrenia: a two-sample Mendelian randomisation study

Although studies suggest that concentrations of omega-3 and omega-6 fatty acids are lower in individuals with schizophrenia, evidence for beneficial effects of fatty acid supplementation is scarce. Therefore, in this study, we aimed to determine whether omega-3 and omega-6 fatty acid concentrations are causally related to schizophrenia. We did a two-sample Mendelian randomisation study, using deidentified summary-level data that were publicly available. Exposure-outcome relationships were evaluated using the inverse variance weighted two-sample Mendelian randomisation method using results from genome-wide association studies (GWASs) of fatty acid concentrations and schizophrenia. GWAS results were available for European (fatty acids) and European and Asian (schizophrenia) ancestry samples. Overall age and gender information were not calculable from the summary-level GWAS results. Weighted median, weighted mode, and Mendelian randomisation Egger regression methods were used as sensitivity analyses. To address underlying mechanisms, further analyses were done using single instruments within the FADS gene cluster and ELOVL2 gene locus. FADS gene cluster and ELOVL2 gene causal effects on schizophrenia were calculated by dividing the single nucleotide polymorphism (SNP)-schizophrenia effect estimate by the SNP-fatty acid effect estimate with standard errors derived using the first term from a delta method expansion for the ratio estimate. Multivariable Mendelian randomisation was used to estimate direct effects of omega-3 fatty acids on schizophrenia, independent of omega-6 fatty acids, lipoproteins (ie, HDL and LDL), and triglycerides. Mendelian randomisation analyses indicated that long-chain omega-3 and long-chain omega-6 fatty acid concentrations were associated with a lower risk of schizophrenia (eg, inverse variance weighted odds ratio [OR] 0·83 [95% CI 0·75-0·92] for docosahexaenoic acid). By contrast, there was weak evidence that short-chain omega-3 and short-chain omega-6 fatty acids were associated with an increased risk of schizophrenia (eg, inverse variance weighted OR 1·07 [95% CI 0·98-1·18] for α-linolenic acid). Effects were consistent across the sensitivity analyses and the FADS single-SNP analyses, suggesting that long-chain omega-3 and long-chain omega-6 fatty acid concentrations were associated with lower risk of schizophrenia (eg, OR 0·74 [95% CI 0·58-0·96] for docosahexaenoic acid) whereas short-chain omega-3 and short-chain omega-6 fatty acid concentrations were associated with an increased risk of schizophrenia (eg, OR 1·08 [95% CI 1·02-1·15] for α-linolenic acid). By contrast, estimates from the ELOVL2 single-SNP analyses were more imprecise and compatible with both risk-increasing and protective effects for each of the fatty acid measures. Multivariable Mendelian randomisation indicated that the protective effect of docosahexaenoic acid on schizophrenia persisted after conditioning on other lipids, although evidence was slightly weaker (multivariable inverse variance weighted OR 0·84 [95% CI 0·71-1·01]). Our results are compatible with the protective effects of long-chain omega-3 and long-chain omega-6 fatty acids on schizophrenia, suggesting that people with schizophrenia might have difficulty converting short-chain polyunsaturated fatty acids to long-chain polyunsaturated fatty acids. Further studies are required to determine whether long-chain polyunsaturated fatty acid supplementation or diet enrichment might help prevent onset of schizophrenia. National Institute for Health Research Biomedical Research Centre at University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol.

Evaluation of cytokines in protective effect of docosahexaenoic acid in experimental achilles tendinopathy rat model induced with type-1 collagenase

ABSTRACT Background We aimed to investigate the effectiveness of docosahexaenoic acid (DHA) as a treatment for Achilles tendinopathy (AT) induced with type-I collagenase in rats and compare it with collagen. Methods The AT model was induced with type I collagenase, and animals were randomly assigned to groups. Group 1:AT, Group 2: Collagen (7.2 mg/kg/day), Group 3:DHA (300 mg/kg/day), and Group 4:DHA (100 mg/kg/day). Right tendons of Group1 were used as a healthy control (HC). Oral treatments were applied for eight weeks. Serum tumor necrosis factor-alpha(TNF-α), matrix metalloproteinase-13 (MMP-13), and interleukin-1 beta(IL-1β) concentrations were determined by ELISA. Tendon samples were taken for histopathological evaluation and examined immunohistochemically with antibodies specific for Col1A1, TNF-α, MMP-13, IL-1β, and nitric oxide synthase-2(NOS-2). The ultimate tensile force (UTF) yield force(YF) and stiffness were measured by biomechanical assessments. Results UTF,YF and stiffness values were increased in all treatment groups compared to the AT control, a significant increase was found in Group 2 (p < 0.05). There was severe degeneration of tendon cells in the AT control. The tendon cells in samples from Groups 2-3 were less degraded, and this was statistically significant (p < 0.05). TNF-α, MMP-13, IL-1β, and NOS-2 expressions were significantly higher in the AT control compared to the HC. In all treatment groups, their concentrations were lower than in the AT control. Serum TNF-α, MMP-13, and IL-1β levels were lower in all treatment groups (Especially in Group3 (p < 0.001)) compared to Group1. Conclusion The efficacy of high-dose DHA as a treatment for AT was investigated from biochemical, histopathological, and biomechanical perspectives. The results showed that DHA could be an alternative treatment compound to collagen.

Toxic effects of formaldehyde and the protective effect of docosahexaenoic acid in Drosophila

Formaldehyde (FA) is a commercially important chemical applied in industry and scientific research. However, FA has a distinct impact on learning and memory. Although the mechanisms of FA toxicity have been well studied, additional research is required to establish the mechanisms of neuroprotection in cases of FA exposure. Docosahexaenoic acid (DHA) is a polyunsaturated fatty acid with a variety of health benefits, including the enhancement of learning and memory. In this study, we investigated the neuroprotective effects of DHA in Drosophila melanogaster that had ingested FA. Our data suggested that DHA enhanced reproductive processes, leading to an increase in the number of eggs, larvae, and adults. Surprisingly, we found that DHA had a mild protective effect against FA-induced impairments in learning and memory.

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.

DHA ameliorates MeHg‑induced PC12 cell apoptosis by inhibiting the ROS/JNK signaling pathway.

Recent studies have reported that methylmercury (MeHg) induces neuronal apoptosis, which is accompanied by abnormal neurological development. Despite the important role of docosahexaenoic acid (DHA) in maintaining the structure and function of the brain, as well as improving neuronal apoptosis induced by MeHg, the exact mechanism remains unknown. The present study hypothesized that the reactive oxygen species (ROS)-mediated JNK signaling pathway may be associated with the protective effect of DHA against MeHg-induced PC12 cell apoptosis. Cell Counting Kit-8, TUNEL staining, flow cytometry, ROS detection, PCR and western blot analysis were performed. The results demonstrated that MeHg inhibited the activity of PC12 cells, causing oxidative damage and promoting apoptosis; however, DHA significantly attenuated this effect. Mechanistic studies revealed that MeHg increased intracellular ROS levels and JNK protein phosphorylation, and decreased the expression levels of the anti-apoptotic protein Bcl-2, whereas DHA reduced ROS levels and JNK phosphorylation, and increased Bcl-2 expression. In addition, the ROS inhibitor N-acetyl-l-cysteine (NAC) was used to verify the experimental results. After pretreatment with NAC, expression levels of Bcl-2, Bax, phosphorylated-JNK and JNK were assessed. Bcl-2 protein expression was increased and the Bcl-2/Bax ratio was increased. Moreover, the high expression levels of phosphorylated-JNK induced by MeHg were significantly decreased. Based on the aforementioned results, the present study indicated that the effects of DHA against MeHg-induced PC12 cell apoptosis may be mediated via the ROS/JNK signaling pathway.

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.

Docosahexaenoic acid inhibits vascular smooth muscle cell migration and proliferation by decreasing microRNA‑155 expression levels.

Vascular smooth muscle cell (VSMC) hyperplasia is a common cause of carotid restenosis. In the present study, the potential protective effects of docosahexaenoic acid (DHA) in carotid restenosis and the underlying mechanism of its effects were examined. VSMCs were treated with DHA, a polyunsaturated ω-3 fatty acid. Cell migration and proliferation were assessed using wound healing and Cell Counting Kit-8 assays and by measuring Ki-67 protein levels. Additionally, the expression levels of microRNA-155 were determined by reverse transcription-quantitative PCR (RT-qPCR). The involvement of microRNA-155 in the regulation of migration and proliferation was evaluated by transfecting VSMCs with microRNA mimics and inhibitors. Moreover, the reversal of migration and proliferation after transfection of VSMCs with the microRNA mimics and subsequent treatment with DHA was investigated. A target gene of microRNA-155 was identified using RT-qPCR and luciferase assays. The migration and proliferation of VSMCs, as well as the expression of microRNA-155 was inhibited by DHA stimulation. MicroRNA-155 regulated the migration and proliferation of VSMCs. Finally, proliferation and migration of VSMCs were reduced following DHA treatment, which was mediated by an increase in the expression levels of microRNA-155. Suppressor of cytokine signalling 1 (Socs1) was the target gene of microRNA-155. In conclusion, DHA inhibited VSMC migration and proliferation by reducing microRNA-155 expression. This effect may be caused by the microRNA-155 target gene Socs1.

DHA Attenuates Hypoxia/Reoxygenation Injury by Activating SSeCKS in Human Cerebrovascular Pericytes

Docosahexaenoic acid (DHA) can alleviate cerebral ischemia/reperfusion injury by reducing blood–brain barrier permeability and maintaining its integrity, accompanied by an increased Ang-1/Ang-2 ratio; however, the underlying mechanisms of these effects remain unclear. Src-suppressed C kinase substrates (SSeCKS), a substrate of protein kinase C, plays an important role in maintaining cell junctions and cell morphology and regulating cell permeability. However, whether DHA can increase SSeCKS expression and then mediate the Ang-1/Ang-2 ratio still needs to be studied. Human cerebrovascular pericytes (HBVPs) cultured in vitro were divided into groups, treated with or without DHA along with SSeCKS siRNA to knockdown SSeCKS expression, and then subjected to 24 h of hypoxia followed by 6 h of reoxygenation. Cell viability; lactate dehydrogenase (LDH) release; and Ang-1, Ang-2 and VEGF activity were detected by using ELISA kits. The apoptosis rate was assessed by TUNEL flow cytometry. Expression of the SSeCKS, Ang-1, Ang-2 and VEGF proteins was evaluated by western blotting. Pretreatment with 10 μM or 40 μM DHA efficiently attenuated hypoxia/reoxygenation (H/R) injury by activating SSeCKS to increase the Ang-1/Ang-2 ratio and downregulate VEGF expression in HBVPs, as evidenced by decreased LDH release and apoptotic rates and increased HBVPs viability. Meanwhile, after we used SSeCKS siRNA to knock down SSeCKS protein expression, the protective effect of DHA on HBVPs following H/R injury was reversed. In conclusion, DHA can activate SSeCKS to increase the Ang-1/Ang-2 ratio and downregulate VEGF expression in HBVPs, thus reducing H/R injury.

Eicosapentaenoic Acid-Enriched Phosphatidylcholine Mitigated Aβ1-42-Induced Neurotoxicity via Autophagy-Inflammasome Pathway.

Recent studies indicated that neuroinflammation contributes to the exacerbation of Alzheimer's disease (AD) and plays an important role in AD. The NOD-like receptor protein 3 (NLRP3) inflammasome, which is an important component of innate immune system, is associated with a wide range of human central nervous system disorders, including AD. Most of the studies focus on the protective effects of docosahexaenoic acid (DHA) in AD, but eicosapentaenoic acid (EPA) has rarely been involved. Here, we investigate the effects of EPA in the forms of phosphatidylcholine (EPA-PC) and ethyl esters (EPA-EE) in improving Aβ1-42-induced neurotoxicity. The spatial memory ability and the biochemical changes in the hippocampus were measured, including glial cell activation, tumor necrosis factor α production, NLRP3 inflammasome activation, and autophagic flux. The present results showed that the AD rats were significantly protected from spatial memory loss by the supplementation (EPA + DHA = 60 mg/kg, i.g., 20 days) of EPA-PC, while EPA-EE showed no significant benefit. Further mechanism studies suggested that EPA-PC could inhibit Aβ-induced neurotoxicity by alleviating NLRP3 inflammasome activation and enhancing autophagy. These findings indicate that EPA could improve cognitive deficiency in Aβ1-42-induced AD rats via autophagic inflammasomal pathway and the bioactivity differs in its molecular form.

Ameliorative effect of docosahexaenoic acid on hepatocyte apoptosis and inflammation induced by oleic acid in grass carp, Ctenopharyngodon idella.

Our previous study has shown that overload of lipid accumulation results in cell apoptosis and inflammation in grass carp (Ctenopharyngodon idella). In this study, we investigated the potential protective effects of docosahexaenoic acid (DHA) on inhibiting oleic acid (OA)-induced apoptosis and inflammation in grass carp hepatocytes. Firstly, the hepatocyte of grass carp were treated with OA (800μM) and different concentration (0, 50, 100 and 200μM) of DHA for 24h, the apoptotic ratio, gene expression levels of apoptosis such as caspase 3, caspase 8, and caspase 9, protein levels of Caspase3, and mRNA levels of inflammation genes such as nf-kb, tnf-α, and il-8 were detected. Furthermore, the mRNA levels of lipogenesis genes srebp1c, fas, acc, and scd and a key enzyme of lipolysis Atgl were also detected. These results showed that the cell apoptosis and the inflammation increased by OA were significantly attenuated by DHA (P < 0.05). Furthermore, DHA could significantly decrease fatty acid synthesis gene expression levels which were induced by OA (P < 0.05). However, the hepatocytes exposed with DHA had no significant influence on the expression of Atgl. Taken together, the study indicated that DHA protects the hepatocytes against apoptosis and inflammation induced by OA might via inhibiting fatty acid synthesis, instead of promoting lipolysis. These results call for further studies to assess the effectiveness of DHA.

Abstract WP343: DHA Adjusts Macrophage Phenotypic Responses After Stroke

Background: Immune responses after stroke, including both in situ glial cell activation and peripheral immune cell infiltration, play critical roles in ischemic brain injury. Systemic docosahexaenoic acid (DHA) has been explored as a clinically feasible protectant in stroke models. However, the mechanism for DHA-afforded neuroprotection remains elusive. This study evaluated the effect of systemic DHA treatment after transient cerebral ischemia and elucidated a mechanism involving immune regulation of macrophages. Methods: Transient middle cerebral artery occlusion (tMCAO) was induced for 1 hour. DHA (i.p., 10mg/kg) was administered immediately after reperfusion and repeated daily for 3 days. Stroke outcomes, systemic inflammatory status and microglia/macrophage phenotypic alterations were assessed 3 days after stroke. Macrophage depletions were induced by clodronate liposomes injection. Primary macrophage cultures were used to evaluate the direct effect of DHA on macrophages. Results: Post-stroke DHA injection efficiently reduced brain infarct and ameliorated neurological deficits 3 days after tMCAO. Systemic DHA treatment significantly inhibited immune cell infiltration (macrophages, neutrophils, T lymphocytes and B lymphocytes) and promoted macrophage polarization towards an anti-inflammatory M2 phenotype in the ischemic brain. Meanwhile, systemic DHA administration inhibited the otherwise elevated pro-inflammatory factors in blood and shifted circulating macrophage polarity toward M2 phenotype after ischemic stroke. The numbers of circulating immune cells in blood and spleen, however, were equivalent between DHA and vehicle treated groups. The protective effects of DHA were macrophage-dependent, as macrophage depletion abolished DHA-afforded neuroprotection. In vitro studies confirmed that DHA suppressed production of chemokines and pro-inflammatory cytokines from macrophages under inflammatory stimulation. Conclusion: Post-stroke DHA treatment ameliorated acute ischemic brain injury in a macrophage-dependent manner. DHA enhanced macrophage phenotypic shift toward an anti-inflammatory phenotype and therefore reduced central and peripheral inflammation after stroke.

Docosahexaenoic acid-flurbiprofen combination ameliorates metaflammation in rats fed on high-carbohydrate high-fat diet

ObjectivePotential benefits of combining docosahexaenoic acid (DHA), an omega-3 fatty acid with flurbiprofen (Flu), a non-steroidal anti-inflammatory drug in ameliorating obesity remain to be elucidated. This study aimed to investigate the possible protective effects of DHA and Flu, either alone or in combination, against obesity-induced metaflammation and to clarify the underlying molecular mechanisms. MethodsSeventy-five male Wistar rats were divided into five groups: normal diet (ND) group, high-carbohydrate high-fat diet (HCHFD) control group, DHA group (HCHFD + 200 mg/kg DHA), Flu group (HCHFD + 10 mg/kg Flu), and DHA + Flu group (HCHFD + DHA + Flu). Treatments were administered orally daily for 8 consecutive weeks, parallel with the start of diets. ResultsPlasma levels of glucose, insulin, and TGs were significantly reduced in DHA, Flu, and DHA + Flu treated groups, while HDL-C concentrations were significantly elevated in the same groups, compared to HCHFD control group. Only Flu and DHA + Flu groups showed a significant decrease in plasma levels of leptin, TC, and LDL-C, relative to HCHFD control group. Concentrations of phosphorylated adenosine monophosphate-activated protein kinase (pAMPK) and resolvin D1 (RvD1) in epididymal adipose tissue (EAT) were significantly increased in the three treated groups, compared with HCHFD control group. Expression of AMPK-α1 subunit in EAT was significantly increased, whereas expression of nuclear factor kappa B (NF-κB) was significantly decreased in EAT of the three treated groups, relative to HCHFD control group. ConclusionsDocosahexaenoic acid-flurbiprofen combination showed an ameliorative effect on obesity-associated metaflammation and its consequences in rats.

Protective effect of docosahexaenoic acid on lipotoxicity-mediated cell death in Schwann cells: Implication of PI3K/AKT and mTORC2 pathways.

Background and AimDocosahexaenoic acid (DHA) exhibits neuroprotective properties and has been shown to preserve nerve cells following trauma and ischemic injury. Recently, we showed that DHA pretreatment improved locomotion and reduced neuropathic pain after acute spinal cord injury in adult rats. These improvements were associated with an increase in the levels of AKT in spinal cord injury neurons. In this study, we investigate the implication of PI3K/AKT and mTOR pathway in DHA‐mediated protection of primary cultured Schwann cells (pSC) undergoing palmitic acid‐induced lipotoxicity (PA‐LTx).MethodsPrimary cultured Schwann cells were treated with PA (PA:BSA, 2:1) in the presence or absence of DHA (1–200 µM) for 24–48 hr. Cell viability was determined by crystal violet staining and nuclear morphology was examined using Hoechst staining.ResultsWe found that pSC cultures exposed to palmitic acid (PA) overload showed chromatin condensation, a decrease in cell viability and an inhibition of AKT phosphorylation in a time‐dependent manner. Next, pSC exposed to PA overload were treated with DHA. The data show that co‐treatment with DHA inhibited the loss of cell viability and apoptosis caused by PA. Moreover, treatment with DHA inhibited chromatin condensation, significantly stimulated p‐AKT phosphorylation under PA‐LTx condition, and DHA alone increased AKT phosphorylation. Additionally, when these pSC cultures were treated with PI3K inhibitors LY294002 and, BKM120 and mTOR inhibitors Torin 1 (mTORC1/mTORC2), but not rapamycin (mTORC1), the protective effects of DHA were not observed.ConclusionThese findings suggest PI3K/AKT and mTORC2 kinase pathways are involved in the protective function (s) of DHA in PA‐induced Schwann cell death.

Post-stroke DHA Treatment Protects Against Acute Ischemic Brain Injury by Skewing Macrophage Polarity Toward the M2 Phenotype.

Systemic docosahexaenoic acid (DHA) has been explored as a clinically feasible protectant in stroke models. However, the mechanism for DHA-afforded neuroprotection remains elusive. Transient middle cerebral artery occlusion (tMCAO) was induced for 1h. DHA (i.p., 10mg/kg) was administered immediately after reperfusion and repeated daily for 3days. Stroke outcomes, systemic inflammatory status, and microglia/macrophage phenotypic alterations were assessed 3days after stroke. Macrophage depletion was induced by clodronate liposomes injection. Primary macrophage cultures were used to evaluate the direct effect of DHA on macrophages. We demonstrated that post-stroke DHA injection efficiently reduced brain infarct and ameliorated neurological deficits 3days after tMCAO. Systemic DHA treatment significantly inhibited immune cell infiltration (macrophages, neutrophils, T lymphocytes, and B lymphocytes) and promoted macrophage polarization toward an anti-inflammatory M2 phenotype in the ischemic brain. Meanwhile, systemic DHA administration inhibited the otherwise elevated pro-inflammatory factors in blood and shifted circulating macrophage polarity toward M2 phenotype after ischemic stroke. The numbers of circulating immune cells in blood and spleen, however, were equivalent between DHA- and vehicle-treated groups. The protective effects of DHA were macrophage-dependent, as macrophage depletion abolished DHA-afforded neuroprotection. In vitro studies confirmed that DHA suppressed production of chemokines and pro-inflammatory cytokines from macrophages under inflammatory stimulation. These data indicate that post-stroke DHA treatment ameliorated acute ischemic brain injury in a macrophage-dependent manner and DHA enhanced macrophage phenotypic shift toward an anti-inflammatory phenotype to reduced central and peripheral inflammation after stroke.

Docosahexaenoic Acid in Combination with Dietary Energy Restriction for Reducing the Risk of Obesity Related Breast Cancer.

There is strong evidence that obesity poses a significant risk factor for postmenopausal breast cancer. There are multiple mechanisms by which obesity can predispose to breast cancer, prominent among which is the creation of a pro-inflammatory milieu systemically in the visceral and subcutaneous tissue, as well as locally in the breast. Although dietary intervention studies have shown in general a favorable effect on biomarkers of breast cancer risk, it is still unclear whether losing excess weight will lower the risk. In this manuscript, we will review the evidence that omega-3 fatty acids, and among them docosahexaenoic acid (DHA) in particular, may reduce the risk of obesity related breast cancer primarily because of their pleotropic effects which target many of the systemic and local oncogenic pathways activated by excess weight. We will also review the evidence indicating that intentional weight loss (IWL) induced by dietary energy restriction (DER) will augment the tumor protective effect of DHA because of its complementary mechanisms of action and its ability to reverse the obesity-induced alterations in fatty acid metabolism predisposing to carcinogenesis. We believe that the combination of DER and DHA is a promising safe and effective intervention for reducing obesity-related breast cancer risk which needs to be validated in appropriately designed prospective, randomized clinical trials.