5-lipoxygenase-dependent biosynthesis of novel 20:4 n-3 metabolites with anti-inflammatory activity

Alternative sources of bioactive omega-3 fatty acids: what are the options?

PURPOSE OF REVIEW

The very-long chain (VLC) omega-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) promote optimal development, physiological function and healthy ageing and help to manage disease. EPA and DHA are sourced mainly from fish, which is not sustainable. This review explores alternative sustainable sources.

RECENT FINDINGS

Recent research confirms that higher intake and status of EPA and DHA are associated with health benefits including lower risk of incident type-2 diabetes and cardiovascular disease mortality. Meta-analyses confirm benefits of intravenous EPA and DHA in hospitalized adults. Algal oils and seed oils from some genetically modified (GM) plants are sources of EPA and DHA. An oil from GM camelina showed equivalence with fish oil in human trials. Ahiflower oil, a source of stearidonic acid, had biological effects in experimental studies that might translate into health benefits. An intravenous lipid emulsion based on Ahiflower oil has been tested in experimental research. Pine nut oil (PNO) is a source of pinolenic acid, which is not an omega-3 PUFA but has similar actions.

SUMMARY

Algal oils, oils from GM seed crops, Ahiflower oil and other sources of stearidonic acid, and nonomega-3 oils including PNO, are plant-sourced sustainable alternatives to fish-sourced VLC omega-3 PUFAs.

Blood and tissue docosahexaenoic acid (DHA, 22:6n-3) turnover rates from Ahiflower® oil are not different than from DHA ethyl ester oil in a diet switch mouse model

Ahiflower® oil is high in α-linolenic and stearidonic acids, however, tissue/blood docosahexaenoic acid (DHA, 22:6n-3) turnover from dietary Ahiflower oil has not been investigated. In this study, we use compound-specific isotope analysis to determine tissue DHA synthesis/turnover from Ahiflower, flaxseed and DHA oils. Pregnant BALB/c mice (13-17 days) were placed on a 2 % algal DHA oil diet of high carbon-13 content (δ13C) and pups (n = 132) were maintained on the diet until 9 weeks old. Mice were then randomly allocated to a low δ13C-n-3 PUFA diet of either: 1) 4 % Ahiflower oil, 2) 4.35 % flaxseed oil or 3) 1 % fish DHA ethyl ester oil for 1, 3, 7, 14, 30, 60 or 120 days (n = 6). Serum, liver, adipose and brains were collected and DHA levels and δ13C were determined. DHA concentrations were highest (p < 0.05) in the liver and adipose of DHA-fed animals with no diet differences in serum or brain (p > 0.05). Based on the presence or absence of overlapping 95 % C.I.'s, DHA half-lives and synthesis/turnover rates were not different between Ahiflower and DHA diets in the liver, adipose or brain. DHA half-lives and synthesis/turnover rates from flaxseed oil were significantly slower than from the DHA diet in all serum/tissues. These findings suggest that the distinct Ahiflower oil n-3 PUFA composition could support tissue DHA needs at a similar rate to dietary DHA, making it a unique plant-based dietary option for maintaining DHA turnover comparably to dietary DHA.

Probiotic-Fermented Distillers Grain Alters the Rumen Microbiome, Metabolome, and Enzyme Activity, Enhancing the Immune Status of Finishing Cattle

A total of 30 Simmental crossbred cattle (6.50 months old, 265.0 ± 22.48 kg) were randomly divided into three groups, with 10 heads per group, and fed for 45 days. The diet treatments consisted of the Control group without PFDG supplementation, the PFDG-15% group with 15% PFDG substituting for 15% concentrate, and PFDG-30% group with 30% PFDG substituting for 30% concentrate. The results showed that compared with the Control group, the average daily gain (ADG) of the cattle in the PFDG-30% group decreased significantly (0.890 vs. 0.768 kg/d, p = 0.005). The serum malondialdehyde content of cattle in the PFDG-15% and PFDG-30% groups decreased significantly (p = 0.047) compared to that of the Control group. However, the serum superoxide dismutase activity of cattle in the PFDG-30% group was significantly higher than that of the Control group (p = 0.047). Meanwhile, both the PFDG-15% and PFDG-30% groups (1758.47 vs. 2061.30 μg/mL) showed higher serum levels of immunoglobulin G, while the interleukin-10 concentration was lower in the PFDG-30% group (p = 0.027). In addition, the PFDG-15% and PFDG-30% groups shifted the rumen microbiota by improving the abundances of F082 (related to propionic acid production) and fiber-degrading bacteria (Lachnospiraceae_UGG-009 and Prevotellaceae_UCG-001) and reducing the abundance of the disease-associated bacteria Selenomonas. A Kyoto encyclopedia of genes and genomes (KEGG) analysis illustrated that three key metabolic pathways, including phenylalanine metabolism, pyrimidine metabolism, and tryptophan metabolism, were enriched in the PFDG-15% group, but eight key metabolic pathways, including arachidonic acid metabolism, were enriched in the PFDG-30% group. Importantly, both the PFDG-15% and PFDG-30% groups increased (p < 0.01) the activities of cellulase, lipase, and protease in the rumen. Finally, the different bacterial abundance in the rumen was associated with changes in the ADG, serum antioxidant capacity, immune status, rumen enzyme activity, and metabolites. These results suggest that PFDG alters rumen microbiome abundance, metabolome, and enzyme activity for enhancing serum antioxidant capacity and the immune status, but when the supplemental level reaches 30%, it has a negative effect on ADG and the anti-inflammatory factors in finishing cattle.

Differences in body wall metabolites of Apostichopus japonicus of different ages in liquid chromatography-tandem mass spectrometry

Apostichopus japonicus is a marine invertebrate with high economic value. Analysis of the effects of age on the structure of this species is important for understanding the status of the population and conservation. In this study, metabolite analysis of the body walls of A. japonicus of three different ages (1, 2, and 3 years) was performed using LC-MS/MS. Metabolite analysis was performed for the KEGG metabolic pathway. The partial least squares-discriminant analysis is clearly distinguished metabolites in the three groups of A. japonicus. A total of 59, 222, and 179 different metabolites were detected in the age 3 vs age 2, age 3 vs age 1, and age 2 vs age 1 controls, respectively (P < 0.05). These metabolic differences involved several metabolic pathways, including phenylalanine metabolism, taurine and hypotaurine metabolism, sulfur metabolism et al. Thiamin, riboflavin, lipoic acid, acetyl l-carnitine levels increase with age, trans-10-heptadecenoic acid, stearic acid, pentadecanoic acid, dibutyl sebacate, and 8,15-diHETE levels decrease with age, which these metabolites can be used as potential markers to determine the age of A. japonicus. Our results provide the foundation for determining the age of A. japonicus and are important for the conservation of germplasm resources of A. japonicus.

Association Between Daily Dietary Eicosatetraenoic Acid Intake and the Lower Risk of Psoriasis in American Adults

Purpose

Unlike eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the relationship between eicosatetraenoic acid (ETA) and psoriasis remains unclear. Therefore, We performed a cross-sectional study in the general American population to investigate the association between daily dietary ETA, EPA, and DHA intake and the risk of psoriasis.

Participants and Methods

This study applied data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006 and 2009-2014. Dietary n3 polyunsaturated fatty acids (PUFA) were calculated based on two 24-hour dietary recall interviews. We defined psoriasis by responding to the question "Have you ever been told by a doctor or other health care professional that you had psoriasis?". Multivariable logistic regression analysis, trend tests, subgroup analysis, and interaction tests were used to evaluate the associations of ETA, EPA, and DHA intake with the risk of psoriasis, respectively.

Results

A total of 15,733 participants were included in this study. In our optimal multivariate-adjusted model, the odds ratio (OR) with 95% confidence interval (CI) of psoriasis were 0.30 (0.12, 0.88), 1.92 (0.78, 4.74), 1.28 (0.72, 2.27) for daily dietary ETA, EPA, and DHA intake, respectively. Trend tests showed a dose-effect relationship between daily dietary ETA intake and the lower risk of psoriasis. Subgroup analysis and tests for interaction showed that the association was stable in different subgroups.

Conclusion

Our study revealed that there might be a dose-effect association of daily dietary ETA intake with the lower risk of psoriasis in American adults.

Imbalance Between Omega-6- and Omega-3-Derived Bioactive Lipids in Arthritis in Older Adults

Elderly-onset rheumatoid arthritis (EORA) and polymyalgia rheumatica (PMR) are common rheumatic diseases in older adults. Oxylipins are bioactive lipids derived from omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) that serve as activators or suppressors of systemic inflammation. We hypothesized that arthritis symptoms in older adults were related to oxylipin-related perturbations. Arthritis in older adults (ARTIEL) is an observational prospective cohort with 64 patients older than 60 years of age with newly diagnosed arthritis. Patients' blood samples at baseline and 3 months posttreatment were compared with 18 controls. A thorough clinical examination was conducted. Serum oxylipins were determined by mass spectrometry. Data processing and statistical analysis were performed in R. Forty-four patients were diagnosed with EORA and 20 with PMR. At diagnosis, EORA patients had a mean DAS28CRP (Disease Activity Score 28 using C-reactive protein) of 5.77 (SD 1.02). One hundred percent of PMR patients reported shoulder pain and 90% reported pelvic pain. Several n-6- and n-3-derived oxylipin species were significantly different between controls and arthritis patients. The ratio of n-3/n-6 PUFA was significantly downregulated in EORA but not in PMR patients as compared to controls. The top two candidates as biomarkers for differentiating PMR from EORA were 4-HDoHE, a hydroxydocosahexaenoic acid, and 8,15-dihydroxy-eicosatrienoic acid (8,15-diHETE). The levels of n-3-derived anti-inflammatory species increased in EORA after treatment. These results suggest that certain oxylipins may be key effectors in arthrtis in older adults and that the imbalance between n-6- and n-3-derived oxylipins might be related to pathobiology in this population.

Plant- and Fish-Derived n-3 PUFAs Suppress Citrobacter Rodentium-Induced Colonic Inflammation

SCOPE

Marine-derived n-3 PUFAs may ameliorate inflammation associated with inflammatory bowel diseases. Plant-derived n-3 PUFAs are thought to be inferior owing to shorter chain lengths. The aim of this study is to compare the impact of plant- and fish-derived PUFAs on murine colitis.

METHODS AND RESULTS

C57BL/6 mice are fed high fat (36% kcal) diets with either 2.5% w/w sunflower oil (SO), flaxseed oil (FSO), ahiflower oil (AO), or fish oil (FO). After 4 weeks, mice are orogastrically challenged with Citrobacter rodentium (10⁸ CFU) or sham gavaged. Fecal shedding is assayed at 2, 7, 10, and 14 days post infection (PI), and fecal microbiota at 14 days PI. Colonic inflammation and lipid mediators are measured. Supplementation regulates intestinal inflammation with crypt lengths being 66, 73, and 62 ±17 µm shorter (compared to SO) for FSO, AO, and FO respectively, p < 0.01. FSO blunts pathogen shedding at the peak of infection and FSO and AO both enhance fecal microbial diversity. FO attenuates levels of lipoxin and leukotriene B₄ while plant oils increase pro-resolving mediator concentrations including D, E, and T-series resolvins.

CONCLUSION

Plant and fish n-3 PUFAs attenuate colitis-induced inflammation while exhibiting characteristic pro-resolving lipid mediator metabolomes. Plant oils additionally promote microbial diversity.