DHA-PC and DHA-PS improved Aβ1–40 induced cognitive deficiency uncoupled with an increase in brain DHA in rats

A Comparative Study about the Neuroprotective Effects of DHA-Enriched Phosphatidylserine and EPA-Enriched Phosphatidylserine against Oxidative Damage in Primary Hippocampal Neurons

Nerve damage caused by accumulated oxidative stress is one of the characteristics and main mechanisms of Alzheimer's disease (AD). Previous studies have shown that phosphatidylserine (PS) rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) plays a significant role in preventing and mitigating the progression of AD. However, whether DHA-PS and EPA-PS can directly protect primary hippocampal neurons against oxidative damage has not been studied. Here, the neuroprotective functions of DHA-PS and EPA-PS against H₂O₂/t-BHP-induced oxidative damage and the possible mechanisms were evaluated in primary hippocampal neurons. It was found that DHA-PS and EPA-PS could significantly improve cell morphology and promote the restoration of neural network structure. Further studies showed that both of them significantly alleviated oxidative stress-mediated mitochondrial dysfunction. EPA-PS significantly inhibited the phosphorylation of ERK, thus playing an anti-apoptotic role, and EPA-PS significantly increased the protein expressions of p-TrkB and p-CREB, thus playing a neuroprotective role. In addition, EPA-PS, rather than DHA-PS could enhance synaptic plasticity by increasing the expression of SYN, and both could significantly reduce the expression levels of p-GSK3β and p-Tau. These results provide a scientific basis for the use of DHA/EPA-enriched phospholipids in the treatment of neurodegenerative diseases, and also provide a reference for the development of related functional foods.

Green biosynthesis of rare DHA-phospholipids by lipase-catalyzed transesterification with edible algal oil in solvent-free system and catalytic mechanism study

Docosahexaenoic acid (DHA)-enriched phosphatidylcholine (PC) has received significant scientific attention due to the health benefits in food and pharmaceutical products. In this work, the edible algal oil rich in DHA-triacylglycerol (DHA-TAG) without pretreatment was first used as the DHA donor for the transesterification of phospholipids (PLs) to prepare three kinds of rare PLs, including DHA-PC, DHA-phosphatidylethanolamine (DHA-PE), and DHA-phosphatidylserine (DHA-PS). Here, 153 protein structures of triacylglycerol lipase (EC 3.1.1.3) were virtually screened and evaluated by transesterification. PLA1 was the best candidate due to a higher DHA incorporation. Results showed that the transesterification of PC with DHA-TAG at 45°C and 0.7% water content (without additional water addition) could produce DHA-PC with 39.1% DHA incorporation at 30 min. The different DHA donors, including forms of fatty acid, methyl ester, and triglycerides, were compared. Molecular dynamics (MD) was used to illustrate the catalytic mechanism at the molecular level containing the diffusions of substrates, the structure-activity relationship of PLA1, and the effect of water content.

Esterification of Docosahexaenoic Acid Enhances Its Transport to the Brain and Its Potential Therapeutic Use in Brain Diseases

Docosahexaenoic acid-containing lysophosphatidylcholine (DHA-LysoPC) is presented as the main transporter of DHA from blood plasma to the brain. This is related to the major facilitator superfamily domain-containing protein 2A (Mfsd2a) symporter expression in the blood-brain barrier that recognizes the various lyso-phospholipids that have choline in their polar head. In order to stabilize the DHA moiety at the sn-2 position of LysoPC, the sn-1 position was esterified by the shortest acetyl chain, creating the structural phospholipid 1-acetyl,2-docosahexaenoyl-glycerophosphocholine (AceDoPC). This small structure modification allows the maintaining of the preferential brain uptake of DHA over non-esterified DHA. Additional properties were found for AceDoPC, such as antioxidant properties, especially due to the aspirin-like acetyl moiety, as well as the capacity to generate acetylcholine in response to the phospholipase D cleavage of the polar head. Esterification of DHA within DHA-LysoPC or AceDoPC could elicit more potent neuroprotective effects against neurological diseases.

Marine Sources of DHA-Rich Phospholipids with Anti-Alzheimer Effect

Alzheimer's disease (AD) is a complex and progressive disease, which affects millions of people around the world. Despite the many efforts over the years to find efficient therapeutics, there is no cure yet. Nonetheless, many compounds have been proven to decrease Alzheimer's symptoms. After a short overview of the hypotheses considered in AD drug development and the drugs approved for AD treatment, which lead to symptom release, we focus on the valorization of natural marine sources that decrease AD symptoms, particularly on docosahexaenoic acid (DHA), an important component in membrane phospholipids and the most abundant n-3 polyunsaturated fatty acids (PUFA) found in gray matter of the brain and in retina and on the DHA-containing phospholipids (DHA-PLs) present in marine sources, namely fish, krill, mollusks and in fisheries and aquaculture by-products. DHA-PLs' bioactivities are presented, namely their properties in anti-neurodegeneration, neuroinflammation, as anticancer agents, as well as their benefits to obesity and visual problems. Fisheries and aquaculture by-products are also highlighted as they have a high content of DHA and DHA-rich phospholipids, can be extracted by green methodologies and should be considered in a circular economy for a healthy sustainable future.

Comparative Analyses of EPA-Phosphatidylcholine, EPA-Lysophosphatidylcholine, and DHA-Lysophosphatidylcholine on DHA and EPA Repletion in n-3 PUFA-Deficient Mice

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) play an important role in maintaining the physiological functions of tissues, and the beneficial effects of DHA/EPA in phospholipid forms have been widely reported. Although lysophosphatidylcholine (LPC) is considered to be the preferred form of DHA supplementation for the brain, the kinetics of DHA and EPA recovery and corresponding changes of n-6 docosapentaenoic acid (DPA) and arachidonic acid (AA) levels in different phospholipid molecules and different tissues after administration of EPA in phosphatidylcholine (PC) and LPC forms and DHA in the LPC form are not clear. Here, we measured the total fatty acids in tissues and fatty acid composition of different phospholipid molecules after gavage administration of equal molar amounts of EPA/DHA in mice with n-3 polyunsaturated fatty acid (PUFA) deficiency induced by maternal dietary deprivation of n-3 PUFA during pregnancy and lactation. The results showed that dietary supplementation with EPA-PC, EPA-LPC, and DHA-LPC exhibited different priorities for EPA or DHA accretion and supplementation efficiency curves in different tissues during the developing period. EPA-PC exhibited a more optimal efficacy in DHA and EPA repletion in serum and hepatic total fatty acids. In terms of DHA recovery in the brain, EPA-LPC and DHA-LPC showed great effects. Meanwhile, the DHA level in total fatty acids and major fractions of phospholipids (PC, PE, and PI + PS) in the heart and bone marrow with the supplementation of DHA-LPC displayed a relatively considerable increase compared with that of EPA supplementation groups. The study provides a reference for the time course of DHA or EPA recovery in phospholipid molecular species in different tissues after the supplementation of EPA-PC, EPA-LPC, and DHA-LPC.

Lipidomics profile of irradiated ground meat to support food safety

Meat irradiation is considered as an effective treatment that expose the advantageous effects on meat preservation. This research, based on untargeted LC-HR orbitrap MS-based lipidomics strategy was meant to estimate the alterations in lipid profile of irradiated chicken, turkey and mixed (chicken, turkey and pork) ground meat in order to evaluate if exists any food safety issue concerning the lipidome alteration. Special attention was paid on oxidation triggered by irradiation. All three matrices exhibited a characteristic lipidome profile which was affected differently by five levels of irradiation intensity. Overall, 345 lipids categorized into 14 subclasses were identified. Remarkably, the oxidized glycerophosphoethanolamines and oxidized glycerophosphoserines were identified in irradiated turkey meat, while for all three categories a characteristic diacylglycerols profile was recognised. Our analytical approach highlighted that the estimation of qualitative variations in lipid portion might be valuable in food inspection purposes, especially when the samples from animal origin are suspected on irradiation treatment.

Comparative Study of DHA with Different Molecular Forms for Ameliorating Osteoporosis by Promoting Chondrocyte-to-Osteoblast Transdifferentiation in the Growth Plate of Ovariectomized Mice

Osteoblasts play a key role in bone remodeling. Recent studies have reported that some hypertrophic chondrocytes co-expressing collagen I(Col I) and collagen X (ColX) could directly transdifferentiate into osteoblasts during endochondral ossification. However, whether nutrition intervention is beneficial to this transformation to improve osteoporosis (OP) remains unknown. In this study, ovariectomy (OVX)-induced OP mice were orally administered with docosahexaenoic acid (DHA) in different molecular forms for 13 weeks. The results showed that both DHA-triglyceride (DHA-TG) and DHA-phosphatidylcholine (DHA-PC) increased the bone mineral density and bone mineral apposition rate in ovariectomized mice, while DHA-ethyl esters (DHA-EE) had little effect. Interestingly, we found that both DHA-PC and DHA-TG increased the height of the growth plate, mainly increasing the number of hypertrophic chondrocytes. Further investigation by simultaneously labeling ColX and ColI indicated that DHA-PC and DHA-TG promoted the number of chondrocyte-transdifferentiated osteoblasts in the growth plate close to the diaphysis, in which DHA-PC performed better than DHA-TG. Apoptosis was not the only fate of hypertrophic chondrocytes. Western blot results showed that both DHA-TG and DHA-PC downregulated the Bax and cleaved-caspase3 expression and upregulated Bcl-2 expression in the growth plate, suggesting that chondrocyte apoptosis is inhibited. Runx2, the key regulator of chondrocyte-to-osteoblast transdifferentiation, was significantly increased by DHA-TG and DHA-PC, while DHA-EE had no effect on the above indicators. To our best knowledge, this is the first report that both DHA-PC and DHA-TG enhanced bone formation via promoting the chondrocyte-to-osteoblast transdifferentiation in the growth plate, contributing to the amelioration of OP. These activities depend on the molecular forms of DHA and their bioavailabilities. Our results provide guidance for the application of fish oil for bone health.

N-3 PUFA-Deficiency in Early Life Exhibits Aggravated MPTP-Induced Neurotoxicity in Old Age while Supplementation with DHA/EPA-Enriched Phospholipids Exerts a Neuroprotective Effect

INTRODUCTION

Malnutrition in early life affects the growth and development of fetus and children, which has a long-term impact on adult health. Previous studies reveal a relationship between dietary omega-3 polyunsaturated fatty acid (n-3 PUFA) content, brain development, and the prevalence of neurodevelopmental disorders and inflammation. However, it is unclear about the effect of n-3 PUFA-deficiency in early life on the development of Parkinson's disease (PD) in old age, as well as the neuroprotective effect of DHA- and EPA-enriched phospholipids (DHA/EPA-PLs) supplemented in old age in long-term n-3 PUFA-deficient mice.

METHODS AND RESULTS

The PD mice induced by 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP) in n-3 PUFA-adequate (N) and -deficient (DEF) group are supplemented with a DHA/EPA-PLs diet for 2 weeks (N+DPL, DEF+DPL). DHA/EPA-PLs supplementation significantly protects against MPTP-induced impairments. The DEF+DPL group shows poorer motor performance, the loss of dopaminergic neurons, mitochondrial dysfunction, and neurodevelopment delay than the N+DPL group, and still did not recover to the Control level.

CONCLUSIONS

Dietary n-3 PUFA-deficiency in early life exhibits more aggravated MPTP-induced neurotoxicity in old age, than DHA/EPA-PLs supplementation recovers brain DHA levels and exerts neuroprotective effects in old age in long-term n-3 PUFA-deficient mice, which might provide a potential dietary guidance.

Comparative evaluation of phosphatidylcholine and phosphatidylserine with different fatty acids on nephrotoxicity in vancomycin-induced mice

Phospholipids reportedly alleviate drug-induced acute kidney injury. However, no study has compared the effect of phospholipids with different fatty acids and polar heads on drug-induced nephrotoxicity. In the present study, we aimed to compare the possible nephroprotection afforded by phosphatidylcholine and phosphatidylserine with different fatty acids in a mouse model of vancomycin-induced nephrotoxicity. Pretreatment with phospholipids rich in docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) doubled the survival time when compared with the model group. Moreover, phospholipids rich in DHA/EPA significantly reduced the serum levels of renal function biomarkers and ameliorated kidney pathologies. In terms of alleviating renal damage, no significant differences were observed between different polar heads in DHA-enriched phospholipids, while phosphatidylserine from soybean was better than phosphatidylcholine in mitigating renal injury. Furthermore, DHA/EPA-enriched phospholipids inhibited vancomycin-induced nephrotoxicity mainly by inhibiting apoptosis and oxidative stress. These results provide a scientific basis for phospholipids as potential ingredients to prevent acute kidney injury.

Omega-3 phospholipids in Pacific blue mackerel (Scomber australasicus) processing by-products

The present study investigated phospholipid content, fatty acid composition and the positional distribution (sn-1,3 and sn-2) of n-3 fatty acids in four blue mackerel processing by-products (head, skin, roe, and male gonad). Total lipid was extracted using hexane/ethanol (1:2) and the analyses were carried out using NMR and GC-FID techniques. On the basis of g wet tissue, blue mackerel roe was a better source of phospholipids (38.6 µmol), compared to head (9.89 µmol), skin (13.5 µmol), and male gonad (10.0 µmol). Total lipid extracted from roe was found to have a higher proportion of n-3 fatty acids (44.4%) including EPA (11.3%) and DHA (27.5%), compared to head (total n-3 = 36.6%; EPA, 9.08%: DHA, 21.9%), skin (total n-3 = 34.8%; EPA, 9.63%; DHA, 19.5%) and male gonad (total n-3 = 42.5%; EPA, 12.1%; DHA, 24.7%). The proportion of EPA in the sn-2 position was substantially higher in fish roe (12.6%) compared to the other by-products (head, 1.91%; skin, 2.22%; male gonad, 2.02%). However, the DPA and DHA content in the sn-2 position did not vary significantly among the various parts (p > 0.05). Phospholipid esterified n-3 fatty acids were higher in roe (55.5%) compared to head (40.9%), skin (21.8%) and male gonad (32%). The present study suggests that blue mackerel roe is the best source of marine n-3 phospholipids among the blue mackerel commercially produced by-products.

Effect of irradiation treatment on the lipid composition and nutritional quality of goat meat

The knowledge of the changes in the lipid species in irradiated goat meat is expected to clarify the beneficial effects of irradiation on meat preservation. This study explored the characteristic lipid composition and the changes in irradiated goat meat based on quantitative lipidomics strategy by LC-MS. Totally, 12 subclasses of 174 lipids were identified with significant differences (p < 0.05, VIP > 1), and the absolute quantitative analysis of characteristic lipids was achieved. Significant lipid variables were involved in the major pathways of glycerophospholipid and sphingolipid metabolism. Moreover, significant increases during irradiation were found in total TG, PC, PE, LPE, Cer, LPC and SPH, while the total DG, PS, PG, PI and SM decreased after irradiation. Noteworthily, DHA-enriched PC (18:4/22:6) + H, a core nutrient for human health, exhibited an increase in the irradiated group. These results provide a basis for lipid quantitative alterations in irradiated goat meat and application of irradiation in meat preservation.

Short-term supplementation of DHA as phospholipids rather than triglycerides improve cognitive deficits induced by maternal omega-3 PUFA deficiency during the late postnatal stage

Cognitive deficiencies, which are caused by maternal omega-3 PUFA deficiency (O-3 Def), are likely to be more rapidly and easily reversed at younger ages with quicker DHA reversal. This study aims to compare the efficiency of short-term supplementation of DHA in the form of phospholipids (PL) and triglycerides (TG) and improve cognitive deficiency in the O-3 Def model during different periods of brain development (3-week and 7-week old). The animal's spatial task performance, brain PUFA concentration, histopathology, and expression of synapse-associated proteins in the hippocampus were then analyzed. We demonstrate here that DHA-PL shows improved efficiency in improving cognitive deficiency compared to DHA-TG, particularly for adult O-3 Def offspring. The superiority of DHA-PL also correlates with the specific elevation of synapse-associated proteins, including BDNF, DCX, GAP-43, Syn, and PSD95, except to higher brain DHA accretion. This work highlights the DHA-PL as a better DHA supplement for inferior brain development caused by maternal O-3 Def, especially regarding those who missed the optimal time window of neurodevelopment.

Isolation of Neuroprotective Anthocyanins from Black Chokeberry (Aronia melanocarpa) against Amyloid-β-Induced Cognitive Impairment

Black chokeberry (Aronia melanocarpa) fruits are rich in anthocyanins, which are vital secondary metabolites that possess antioxidative properties. The aim of this study was to isolate and purify the anthocyanins from black chokeberry by simulated moving bed (SMB) chromatography, and to investigate the neuroprotective effect of SMB purified anthocyanin against Aβ-induced memory damage in rats. The parameters of the SMB process were studied and optimized. Anthocyanin extracts were identified by HPLC and UPLC-QTOF-MS, and antioxidant abilities were evaluated. The Aβ-induced animal model was established by intracerebral ventricle injection in rat brain. Through the SMB purification, anthocyanins were purified to 85%; cyanidin 3-O-galactoside and cyanidin 3-O-arabinoside were identified as the main anthocyanins by UPLC-QTOF-MS. The SMB purified anthocyanins exhibited higher DPPH and ABTS free radical scavenging abilities than the crude anthocyanins extract. Furthermore, rats receiving SMB purified anthocyanins treatment (50 mg/kg) showed improved spatial memory in a Morris water maze test, as well as protection of the cells in the hippocampus against Aβ toxicity. These results demonstrate that anthocyanins could serve as antioxidant and neuroprotective agents, with potential in the treatment of Alzheimer's disease.

Structured form of DHA prevents neurodegenerative disorders: A better insight into the pathophysiology and the mechanism of DHA transport to the brain

Docosahexaenoic acid (DHA) is one of the most important fatty acids that plays a critical role in maintaining proper brain function and cognitive development. Deficiency of DHA leads to several neurodegenerative disorders and, therefore, dietary supplementations of these fatty acids are essential to maintain cognitive health. However, the complete picture of how DHA is incorporated into the brain is yet to be explored. In general, the de novo synthesis of DHA is poor, and targeting the brain with specific phospholipid carriers provides novel insights into the process of reduction of disease progression. Recent studies have suggested that compared to triacylglycerol form of DHA, esterified form of DHA (i.e., lysophosphatidylcholine [lysoPC]) is better incorporated into the brain. Free DHA is transported across the outer membrane leaflet of the blood-brain barrier via APOE4 receptors, whereas DHA-lysoPC is transported across the inner membrane leaflet of the blood-brain barrier via a specific protein called Mfsd2a. Dietary supplementation of this lysoPC specific form of DHA is a novel therapy and is used to decrease the risk of various neurodegenerative disorders. Currently, structured glycerides of DHA - novel nutraceutical agents - are being widely used for the prevention and treatment of various neurological diseases. However, it is important to fully understand their metabolic regulation and mechanism of transportation to the brain. This article comprehensively reviews various studies that have evaluated the bioavailability of DHA, mechanisms of DHA transport, and role of DHA in preventing neurodegenerative disorders, which provides better insight into the pathophysiology of these disorders and use of structured DHA in improving neurological health.

Phosphatidylserine from Portunus trituberculatus Eggs Alleviates Insulin Resistance and Alters the Gut Microbiota in High-Fat-Diet-Fed Mice

Portunus trituberculatus eggs contain phospholipids, whose components and bioactivity are unclear. Here, we investigated the fatty acid composition of phosphatidylserine from P. trituberculatus eggs (Pt-PS). Moreover, its effects on insulin resistance and gut microbiota were also evaluated in high-fat-diet-fed mice. Our results showed that Pt-PS accounted for 26.51% of phospholipids and contained abundant polyunsaturated fatty acids (more than 50% of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)). Animal experiments indicated that Pt-PS significantly decreased body weight and adipose weight gain, improved hyperglycemia and hyperinsulinemia, mitigated insulin resistance, and regulated circulatory cytokines. Pt-PS activated insulin receptor substrate 1 (IRS1) and increased the levels of IRS1-associated phosphatidylinositol 3-hydroxy kinase (PI3K), phosphorylated protein kinase B (Akt) protein, and plasma membrane glucose transporter 4 protein. Furthermore, Pt-PS modified the gut microbiota, inducing, especially, a dramatic decrease in the ratio of Firmicutes to Bacteroidetes at the phylum level, as well as a remarkable improvement in their subordinate categories. Pt-PS also reduced fecal lipopolysaccharide concentration and enhanced fecal acetate, propionate, and butyrate concentrations. Additionally, the effects of Pt-PS on alleviation of insulin resistance and regulation of intestinal bacteria were better than those of phosphatidylserine from soybean. These results suggest that Pt-PS mitigates insulin resistance by altering the gut microbiota. Therefore, Pt-PS may be developed as an effective food supplement for the inhibition of insulin resistance and the regulation of human gut health.

Polyunsaturated fatty acids synthesized by freshwater fish: A new insight to the roles of elovl2 and elovl5 in vivo

At present, fish provide an important supply of long-chain polyunsaturated fatty acids (LC-PUFAs) for human consumption. Previous studies have shown that fatty acyl elongase 2 (elovl2) and elovl5 play important roles in fish LC-PUFA synthesis. Generally, freshwater fish have a stronger ability to synthesize LC-PUFAs than marine fish. However, the roles of elovl2, elovl5 and elovl2 + elovl5 in LC-PUFA synthesis of freshwater fish in vivo are not very clear. In this study, the elovl2 knockout zebrafish (elovl2^-/-), elovl5 knockout zebrafish (elovl5^-/-) and the double gene knockout zebrafish (DKO) were generated by CRISPR/Cas9 technology for the first time. Compared with wild type zebrafish (WT), elovl5-deletion zebrafish showed a significant increase in C22 PUFA content, which might be due to the up-regulation expressions of elovl4b and elovl2. elovl5 expressed at very low levels in livers of elovl2^-/- relative to WT, indicating that elovl5 may be an "assistant attacker" of elovl2 in LC-PUFA synthesis of zebrafish. Moreover, there were no significant differences in levels of C18-C22 PUFAs between DKO and WT, indicating that besides elovl2 + elovl5 path, LC-PUFA synthesis in zebrafish could be performed by other paths. In addition, the hepatic lipidomic analysis results revealed that the contents of C22:6n-3 in phosphatidyl ethanolamine (PE-DHA) and PE-C22 PUFAs were more easily affected by the absence of elovl2 and elovl5. Our results suggest that the elovl2+elovl5 path is not the only path for LC-PUFA synthesis in zebrafish, and provide novel insights into the roles of elovl2 and elovl5 in LC-PUFA synthesis of freshwater fish.

Comparative study on the digestion and absorption characteristics of n-3 LCPUFA-enriched phospholipids in the form of liposomes and emulsions

Previous studies have reported that phospholipids rich in n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) in the form of liposome exhibited superior bioactivities than other formulation. However, the digestion and absorption characteristics of n-3 LCPUFA-enriched phospholipids were still unclear, restricting the molecular mechanism analysis related to their distinctive activities. The aim of the present study was to compare the digestion and absorption characteristics of DHA/EPA-PC in the forms of liposome and emulsion. The fatty acid composition and lipid species in serum, intestinal wall and content of healthy mice were determined after oral administration with DHA/EPA-PC. Results showed that the peak value of serum DHA/EPA level in the liposome group was significantly higher than that of the emulsion group (p < 0.05), although the peak in the liposome group appeared at 3 h and the peak time was 2 h in the emulsion group. Lipidomics analysis indicated that the high levels of total PL and PL-DHA could be retained in serum for a substantial period after administration of the DHA/EPA-PC liposome, which might be attributed to that the DHA/EPA-PC in the form of liposomes was hydrolyzed slower by pancreatic phospholipase A2 than the emulsion form in small intestinal content. The obtained results might provide theoretical basis for the development and utilization of marine-derived phospholipids.

Recovery of brain DHA-containing phosphatidylserine and ethanolamine plasmalogen after dietary DHA-enriched phosphatidylcholine and phosphatidylserine in SAMP8 mice fed with high-fat diet

Background

Glycerophospholipids were the main components of cerebral cortex lipids, and there was a close association between lipid homeostasis and human health. It has been reported that dietary DHA-enriched phosphatidylcholine (DHA-PC) and phosphatidylserine (DHA-PS) could improve brain function. However, it was unclear that whether supplementation of DHA-PC and DHA-PS could change lipid profiles in the brain of dementia animals.

Methods

SAMP8 mice was fed with different diet patterns for 2 months, including high-fat diet and low-fat diet. After intervention with DHA-PC and DHA-PS for another 2 months, the lipid profile in cerebral cortex was determined by lipidomics in dementia mice.

Results

High-fat diet could significantly decrease the levels of DHA-containing PS/pPE, DPA-containing PS, and AA-containing PE, which might exhibit the potential of lipid biomarkers for the prevention and diagnosis of AD. Notably, DHA-PC and DHA-PS remarkably recovered the lipid homeostasis in dementia mice. These might provide a potential novel therapy strategy and direction of dietary intervention for patients with cognitive decline.

Conclusions

DHA-PC and DHA-PS could recover the content of brain DHA-containing PS and pPE in SAMP8 mice fed with high-fat diet.

Abstract graphical

Advances in exogenous docosahexaenoic acid-containing phospholipids: Sources, positional isomerism, biological activities, and advantages

In recent years, docosahexaenoic acid-containing phospholipids (DHA-PLs) have attracted much attention because of theirs unique health benefits. Compared with other forms of docosahexaenoic acid (DHA), DHA-PLs possess superior biological effects (e.g., anticancer, lipid metabolism regulation, visual development, and brain and nervous system biochemical reactions), more intricate metabolism mechanisms, and a stronger attraction to consumer. The production of DHA-PLs is hampered by several challenges associated with the limited content of DHA-PLs in natural sources, incomplete utilization of by-products, few microorganisms for DHA-PLs production, high cost, and complex process of artificial preparation of DHA-PLs. In this article, the sources, biological activities, and commercial applications of DHA-PLs were summarized, with intensive discussions on advantages of DHA-PLs over DHA, isomerism of DHA in phospholipids (PLs), and brain health. The excellent biological characteristics of DHA-PLs are primarily concerned with DHA and PLs. The metabolic fate of different DHA-PLs varies from the position of DHA in PLs to polar groups in DHA-PLs. Overall, well understanding of DHA-PLs about their sources and characteristics is critical to accelerate the production of DHA-PLs, economically enhance the value of DHA-PLs, and improve the applicability of DHA-PLs and the acceptance of consumers.

Marine omega-3 (n-3) phospholipids: A comprehensive review of their properties, sources, bioavailability, and relation to brain health

For several decades, there has been considerable interest in marine-derived long chain n-3 fatty acids (n-3 LCPUFAs) due to their outstanding health benefits. n-3 LCPUFAs can be found in nature either in triglycerides (TAGs) or in phospholipid (PL) form. From brain health point of view, PL n-3 is more bioavailable and potent compared to n-3 in TAG form, as only PL n-3 is able to cross the blood-brain barrier and can be involved in brain biochemical reactions. However, PL n-3 has been ignored in the fish oil industry and frequently removed as an impurity during degumming processes. As a result, PL products derived from marine sources are very limited compared to TAG products. Commercially, PLs are being used in pharmaceutical industries as drug carriers, in food manufacturing as emulsifiers and in cosmetic industries as skin care agents, but most of the PLs used in these applications are produced from vegetable sources that contain less (without EPA, DPA, and DHA) or sometimes no n-3 LCPUFAs. This review provides a comprehensive account of the properties, structures, and major sources of marine PLs, and provides focussed discussion of their relationship to brain health. Epidemiological, laboratory, and clinical studies on n-3 LCPUFAs enriched PLs using different model systems in relation to brain and mental health that have been published over the past few years are discussed in detail.

Peanut Oil Body Composition and Stability

This study was aimed to assess the effect of membrane structure on the stability of peanut oil bodies extracted by enzyme-assisted extraction. The influence of pH, NaCl concentration, and temperature on the physicochemical properties of peanut oil bodies was characterized using ζ-potential and particle size. The results indicated that the peanut oil bodies had strong stability (ζ-potential, >20 mV) at pH values away from the isoelectric point (pH 4.8), at a low salt concentration (NaCl concentration, <10 mM), and in a certain temperature range (35 to 55 °C). The stable structure of the oil body was closely related to its structure. Phospholipids, along with membrane proteins, were major components of the oil body membrane. Therefore, the phospholipid composition and content were measured and the types of membrane proteins of the oil bodies were identified. The results showed that phosphatidylcholine and phosphatidylserine were major components of the oil body phospholipids. Two-dimensional electrophoresis showed that the oil bodies contained both intrinsic proteins and extrinsic proteins, which might play an important role in the stability of oil bodies during enzyme-assisted extraction processing.

DHA-PC protects kidneys against cisplatin-induced toxicity and its underlying mechanisms in mice

DHA-PC protected the kidney against cisplatin-induced toxicity through sirtuin 1 activation, the inhibition of oxidative stress and apoptosis.

Comparative studies of DHA-enriched phosphatidylcholine and recombination of DHA-ethyl ester with egg phosphatidylcholine on ameliorating memory and cognitive deficiency in SAMP8 mice

DHA-PLs (DHA-PC) could not be substituted by recombination of commercial fish oil with DHA-free PC in alleviating age-related memory loss and cognitive deficiency in SAMP8 mice.

Manufacture and characterization of anti-inflammatory liposomes from jumbo flying squid (Dosidicus gigas) skin phospholipid extraction

The anti-inflammation properties of marine phospholipids enriched with n-3 fatty acids contribute to anti-inflammatory and inflammation-resolving mediators. Functional squid-skin (SQ) liposomes were manufactured from squid-skin phospholipids, and their anti-inflammatory effects were investigated. SQ liposomes included phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and lysophosphatidylcholine (Lyso-PC), and had an approximate diameter of 100 mm. When RAW264.7 cells were treated with the SQ liposome, no (p > 0.05) cytotoxicity was observed below a concentration of 7.5 mg mL-1. An SQ-liposome pretreatment of lipopolysaccharide (LPS)-induced RAW 264.7 cells showed decreased (p < 0.05) prostaglandin E2 (PGE2), nitric oxide (NO), interleukin-1beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α). The engulfment of SQ liposomes by the RAW264.7 cells resulted in lower (p < 0.05) LPS-induced intracellular levels of reactive oxygen species. Furthermore, an SQ-liposome administration ameliorated (p < 0.05) carrageenan-induced paw edema in mice. SQ liposomes may act via apoptotic mimicry to elicit the resolution of inflammation and prevent chronic inflammation-related diseases.

Mechanisms of DHA-enriched phospholipids in improving cognitive deficits in aged SAMP8 mice with high-fat diet

Recent studies have shown that a high-fat diet (HFD) is involved in both metabolic dysfunction and cognitive deficiency and that docosahexaenoic-acid-enriched phospholipids (DHA-PLs) have beneficial effects on obesity and cognitive impairment. However, there are only a few studies comparing differences between DHA-PC and DHA-PS in HFD-induced Alzheimer's disease (AD) models. After 8 weeks feeding with HFD, 10-month-old SAMP8 mice were fed with 1% (w/w) DHA-PC or 1% DHA-PS (biosynthesized from DHA-PC) for 8 weeks; we then tested the behavioral performances in the Barnes maze test and Morris maze test. The changes of the generation and accumulation of Aβ, oxidative stress, apoptosis, neuroinflammation and neurotrophic factors were also measured. The results indicated that both DHA-PC and DHA-PS significantly improved the metabolic disorders and cognitive deficits. Both DHA-PC and DHA-PS could ameliorate oxidative stress, and DHA-PS presented more notable benefits than DHA-PC on Aβ pathology, mitochondrial damage, neuroinflammation and neurotrophic factors; DHA-PS was for the first time found to increase the production of insoluble Aβ (less pathogenic) in this AD model. These data suggest that DHA-PLs can significantly improve cognitive deficiency, and the molecular mechanisms for this closely relate to the phospholipid polar groups.

Glycerophospholipid Supplementation as a Potential Intervention for Supporting Cerebral Structure in Older Adults

Modifying nutritional intake through supplementation may be efficacious for altering the trajectory of cerebral structural decline evident with increasing age. To date, there have been a number of clinical trials in older adults whereby chronic supplementation with B vitamins, omega-3 fatty acids, or resveratrol, has been observed to either slow the rate of decline or repair cerebral tissue. There is also some evidence from animal studies indicating that supplementation with glycerophospholipids (GPL) may benefit cerebral structure, though these effects have not yet been investigated in adult humans. Despite this paucity of research, there are a number of factors predicting poorer cerebral structure in older humans, which GPL supplementation appears to beneficially modify or protect against. These include elevated concentrations of homocysteine, unbalanced activity of reactive oxygen species both increasing the risk of oxidative stress, increased concentrations of pro-inflammatory messengers, as well as poorer cardio- and cerebrovascular function. As such, it is hypothesized that GPL supplementation will support cerebral structure in older adults. These cerebral effects may influence cognitive function. The current review aims to provide a theoretical basis for future clinical trials investigating the effects of GPL supplementation on cerebral structural integrity in older adults.

Comparative Analysis of EPA/DHA-PL Forage and Liposomes in Orotic Acid-Induced Nonalcoholic Fatty Liver Rats and Their Related Mechanisms

Nonalcoholic fatty liver disease (NAFLD) has become one predictive factor of death from various illnesses. The present study was to comparatively investigate the effects of eicosapentaenoic acid-enriched and docosahexaenoic acid-enriched phospholipids forage (EPA-PL and DHA-PL) and liposomes (lipo-EPA and lipo-DHA) on NAFLD and demonstrate the possible protective mechanisms involved. The additive doses of EPA-PL and DHA-PL in all treatment groups were 1% of total diets, respectively. The results showed that Lipo-EPA could significantly improve hepatic function by down-regulating orotic acid-induced serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels by 55.6% and 34.2%, respectively (p < 0.01). Moreover, lipo-EPA exhibited excellent inhibition on the mRNA expression of SREBP-1c and FAS at the values of 0.454 ± 0.09 (p < 0.01) and 0.523 ± 0.08 (p < 0.01), respectively, thus ameliorating OA-induced NAFLD. Meanwhile, lipo-EPA could significantly suppress the SREBP-2 and HMGR levels (31.4% and 66.7%, p < 0.05, respectively). In addition, EPA-PL and lipo-DHA could also significantly suppress hepatic lipid accumulation mainly by enhancement of hepatic lipolysis and cholesterol efflux. Furthermore, DHA-PL played a certain role in inhibiting hepatic lipogenesis and accelerating cholesterol efflux. The results obtained in this work might contribute to the understanding of the biological activities of EPA/DHA-PL and liposomes and further investigation on its potential application values for food supplements.

The Protective Effect of Antarctic Krill Oil on Cognitive Function by Inhibiting Oxidative Stress in the Brain of Senescence-Accelerated Prone Mouse Strain 8 (SAMP8) Mice

Alzheimer's disease (AD) is a common neurodegenerative disorder, and oxidative stress plays a vital role in its progression. Antarctic krill oil (AKO) is rich in polyunsaturated fatty acids, which has various biological activities, such as improving insulin sensitivity, alleviating inflammation and ameliorating oxidative stress. In this study, the protective effect of AKO against AD were investigated in senescence-accelerated prone mouse strain 8 (SAMP8) mice. Results showed that treatment with AKO could effectively ameliorate learning and memory deficits and ease the anxiety in SAMP8 mice by Morris water maze, Barnes maze test and open-field test. Further analysis indicated that AKO might reduce β-amyloid (Aβ) accumulation in hippocampus through decreasing the contents of malondialdehyde (MDA) and 7,8-dihydro-8-oxoguanine (8-oxo-G), increasing the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the brain of SAMP8 mice.

PRACTICAL APPLICATION

The results of Morris water maze, Barnes maze test and open-field test indicated that Antarctic krill oil (AKO) improved the cognitive function and anxiety of SAMP8 mice. AKO reduced the Aβ₄₂ level in hippocampus of SAMP8 mice. AKO ameliorated oxidative stress in brain rather than in serum and liver of SAMP8 mice.

Protective Effects of DHA-PC against Vancomycin-Induced Nephrotoxicity through the Inhibition of Oxidative Stress and Apoptosis in BALB/c Mice

The clinical use of glycopeptide antibiotic vancomycin is usually accompanied by nephrotoxicity, limiting its application and therapeutic efficiency. The aim of this study was to investigate the protection of DHA-enriched phosphatidylcholine (DHA-PC) against nephrotoxicity using a model of vancomycin-induced male BALB/c mice with renal injury by measuring death curves, histological changes, and renal function indexes. The addition of DHA in DHA and DHA-PC groups were 300 mg/kg per day on the basis of human intake level in our study. Results indicated that DHA-PC could dramatically extend the survival time of mice, while traditional DHA and PC had no significant effects. Moreover, oral administration of DHA-PC exhibited better effects on reducing vancomycin-induced increases of blood urea nitrogen, creatinine, cystatin C, and kidney injury molecule-1 levels than traditional DHA and PC. DHA-PC significantly delayed the development of vancomycin-induced renal injury, including tubular necrosis, hyaline casts, and tubular degeneration. A further mechanistic study revealed that the protective effect of DHA-PC on vancomycin-mediated toxicity might be attributed to its ability to inhibit oxidative stress and inactivate mitogen-activated protein kinase (MAPK) signaling pathways, which was associated with upregulation of Bcl-2 and downregulation of caspase-9, caspase-3, cytochrome-c, p38, and JNK. These findings suggest that DHA-PC may be acted as the dietary supplements or functional foods against vancomycin-induced nephrotoxicity.

Replenishment of Docosahexaenoic Acid (DHA) in Dietary n-3-Deficient Mice Fed DHA in Triglycerides or Phosphatidylcholines After Weaning

Previous studies have shown that DHA in triglyceride (TG) and phosphatidylcholine (PC) forms are different in their bioavailability. The aim of this study was to investigate the comparative effects of DHA-TG and DHA-PC on tissue DHA accretion in dietary n-3 polyunsaturated fatty acid deficient (n-3 Def) mice. The mice were fed with n-3 Def diet containing DHA-TG or DHA-PC (5 g/kg diet) for 2, 4, 7, or 14 d after weaning, respectively. The DHA levels in the cortex, liver, testis, and erythrocytes were analyzed by gas chromatography. For liver, DHA mainly existed in hepatic phospholipids relative to triglycerides. Both DHA-TG and DHA-PC could recover the hepatic DHA to a normal level. Interestingly, DHA-TG was more effective in increasing the DHA level in hepatic triglycerides, and DHA-PC was more effective in increasing the DHA level in hepatic phospholipids. For erythrocytes, during the first 7 d, no difference was observed after dietary DHA-TG and DHA-PC but a significantly higher DHA percentage was detected in the DHA-PC group after 14 d. For cortex, the DHA-TG group showed a higher cortical DHA level at the 4th day, but the DHA-PC group showed a higher cortical DHA level with a greater slope from Day 7 to Day 14, and the same trend was observed in testis. But unexpectedly, the DHA level in testis showed a downtrend from Day 7 to Day 14. This study suggests that, under dietary n-3-deficient condition, both DHA-TG and DHA-PC could recover the DHA level in tissues after weaning, and DHA-PC showed a better supplemental effect.

PRACTICAL APPLICATION

Dietary DHA is essential for neurodevelopment which is usually accompanied by large amounts of DHA accretion in the brain. Our present study showed that DHA-PC had a better efficiency for DHA accretion in the brain and other tissues compared with DHA-TG. The findings are supposed to pave the way for the DHA in phospholipids as a novel nutrient added into the infant formula and assisted food for neurodevelopment.

A comparative study of EPA-enriched ethanolamine plasmalogen and EPA-enriched phosphatidylethanolamine on Aβ42 induced cognitive deficiency in a rat model of Alzheimer's disease

The possible molecular mechanism of EPA-pPE and EPA-PE on AD.

Comparative analyses of DHA-Phosphatidylcholine and recombination of DHA-Triglyceride with Egg-Phosphatidylcholine or Glycerylphosphorylcholine on DHA repletion in n-3 deficient mice

Background

Docosahexaenoic acid (DHA) is important for optimal neurodevelopment and brain function during the childhood when the brain is still under development.

Methods

The effects of DHA-Phosphatidylcholine (DHA-PC) and the recombination of DHA-Triglyceride with egg PC (DHA-TG + PC) or α-Glycerylphosphorylcholine (DHA-TG + α-GPC) were comparatively analyzed on DHA recovery and the DHA accumulation kinetics in tissues including cerebral cortex, erythrocyte, liver, and testis were evaluated in the weaning n-3 deficient mice.

Results

The concentration of DHA in weaning n-3 deficient mice could be recovered rapidly by dietary DHA supplementation, in which DHA-PC exhibited the better efficacy than the recombination of DHA-Triglyceride with egg PC or α-GPC. Interestingly, DHA-TG + α-GPC exhibited the greater effect on DHA accumulation than DHA-TG + PC in cerebral cortex and erythrocyte (p < 0.05), which was similar to DHA-PC. Meanwhile, DHA-TG + PC showed a similar effect to DHA-PC on DHA repletion in testis, which was better than that of DHA-TG + α-GPC (p < 0.05).

Conclusion

We concluded that different forms of DHA supplements could be applied targetedly based on the DHA recovery in different tissues, although the supplemental effects of the recombination of DHA-Triglyceride with egg PC or α-GPC were not completely equivalent to that of DHA-PC, which could provide some references to develop functional foods to support brain development and function.

Neuroprotective Effects of n-3 Polyunsaturated Fatty Acid-Enriched Phosphatidylserine Against Oxidative Damage in PC12 Cells

Neurodegenerative diseases are defined by progressive loss of specific neuronal cell populations and are associated with protein aggregates. Oxidative stress has been implicated in their pathological processes. Previous studies revealed that docosahexaenoic acid (DHA) is beneficial in neurodegenerative diseases. Phospholipids (PLs) derived from marine products are rich in DHA and eicosapentaenoic acid (EPA). In the present study, we investigated the neuroprotective effects of DHA-enriched and unenriched phosphatidylcholine (PC) and phosphatidylserine (PS) on oxidative stress induced by hydrogen peroxide (H₂O₂) and tert-butylhydroperoxide in PC12 cells. Cell viability and leakage of lactate dehydrogenase results showed that the neuroprotective effect of PS was superior to that of PC. DHA- and EPA-enriched PC and PS were superior to that without DHA or EPA; in addition, the improvement with n-3 polyunsaturated fatty acid-enriched PS (n-3 PS) was dose dependent. Acridine orange/ethidium bromide staining showed that DHA- and EPA-enriched PS (DHA/EPA-PS) could significantly inhibit apoptosis. Mechanistic studies revealed that EPA-PS and DHA-PS were effective to increase superoxide dismutase (SOD) levels by 48.4 and 58.2 % and total antioxidant capacity (T-AOC) level by 51 and 94 %, respectively, in the H₂O₂ model. Similar results for SOD and T-AOC levels were shown in the t-BHP model. EPA/DHA-PS could downregulate the messenger RNA level of Caspase-3, Caspase-9, and Bax, upregulate Bcl-2, inhibit Bax, and increase Bcl-2 at protein level. In conclusion, EPA/DHA-PS could protect PC12 cells from oxidative stress and prevent mitochondrial-mediated apoptosis. Our findings indicate that the neuroprotective effects of DHA/EPA-PLs depend on the molecular form. Further studies are necessary to reveal detailed mechanisms and structure-effect relationships.