Levels Of Long-chain Fatty Acids Research Articles

Course-based intra-articular injection of medical chitosan mitigates excessive deposition of triacylglycerides in the synovial tissue of the knee osteoarthritis.

This study aimed to investigate the clinical efficacy of intra-articular injections of medical chitosan for treating knee osteoarthritis (KOA) and measure the lipid metabolism profiles of the synovial tissue. 60 patients with KOA undergoing conservative treatment were recruited and randomized into two groups: one without pharmacological intervention (OA group) and the other receiving course-based intra-articular medical chitosan injections (CSI group). Quantitative lipidomic profile of synovial tissue was analyzed. Functional scores, including Kellgren-Lawrence rating (K-L), VAS, WOMAC scoring, and AKS scoring were conducted. Survival from the initial conservative treatment to final knee arthroplasty was significantly longer in the CSI group compared to the OA group. Except for the pre-surgery VAS score, no statistically significant differences were observed in the other scores, including K-L, initial VAS, WOMAC, and AKS. However, the CSI group experienced a slightly more pronounced decline in AKS-Knee subscores compared to the OA group. Compared to the CSI group, the OA group exhibited a significant upregulation in most differential lipids, particularly triacylglycerides (TAGs, 77%). The OA group had notably higher levels of long-chain unsaturated fatty acids. Intra-articular injection of medical chitosan significantly prolongs the survival period before knee arthroplasty and reduces the deposition of TAGs metabolites.

Proximate and fatty acids composition in the muscle of wild and farmed sardine (Sardinella brasiliensis)

Wild sardines contain a high level (2560 mg/100 g n-3 LC-PUFA of wet mass) of long-chain (≥C20) polyunsaturated fatty acids (LC-PUFA), namely, PUFA with 20 and 22 carbon atoms, however, in captivity their fatty acid composition can be affected by food and farming conditions. Therefore, this study evaluated the proximate composition and fatty acid profile of sardines cultivated in the four seasons of the year as well as compared to those captured in the wild in the spring. In both analyses, farmed sardines differed significantly from wild specimens. Total lipid content was significantly higher, especially in winter, with 14.52 % and 2.37 % for farmed and wild sardines, respectively. The fatty acid profile had a prevalence of n-3 LC-PUFA in wild fish (17.6 %) and n-6 PUFA ​​in farmed fish (12.2 %). LC-PUFA showed higher relative levels in wild animals, 16.4 % against 1.2 % for farmed sardines in winter. In absolute terms, the amount of EPA (eicosapentaenoicacid) and DHA (docosahexaenoicacid) in farmed sardine was similar to the wild specimens in spring 4000 mg/100 g and 3000 mg/100 g, respectively.

Isolation of intake mediated effects demonstrate that the phenomic benefits of dietary omega-3 are nominal to Atlantic salmon when reared in a challenging (hypoxic) environment

The present study was designed to examine whether challenging environmental conditions (such as hypoxia) influence a fish's response to diet by changing responses to nutrient utilisation or down-regulation of appetite. To examine this, post-smolt Atlantic salmon (138.8 ± 0.65 g/fish; mean ± SD) were fed sub- (2.6% TFA; Ln3) and optimal (6.0% TFA; Hn3) levels of long-chain polyunsaturated omega-3 fatty acids (n-3 LC-PUFA) when maintained under either normoxic (8.1 ± 0.6 mg/L) or hypoxic (6.8 ± 0.5 mg/L) environmental conditions. To control for the anticipated effects of hypoxia on appetite and food intake, two additional treatments included the two diets that were pair-fed to the same intake levels as in the hypoxic treatments. The reduction in dissolved oxygen was accompanied by an increase in dissolved CO2 and decline in seawater pH, with no change in total alkalinity. After 138 days of the study the fish increased their average weight to between 616 and 720 g/fish subject to treatment. Hypoxia had a significant negative impact on final weight and weight gain, and these were the result primarily of effects on feed intake. No effects of treatments on feed conversion were observed. Significant diet x oxygen interactions were observed on whole-body lipid levels, but no other proximate compositional parameters. Sub-clinical effects of hypoxia and ration on several plasma chemistry parameters were observed, but few responses were diet related. Hypoxia affected plasma total protein, cholesterol, and red blood cell counts. Diet digestibility was typically not affected by hypoxia or ration, though a range of diet related effects were evident. Nutrient retention data showed evidence of elongation and desaturation of dietary short-chain PUFA, with clear effects of diet affecting the deposition of both omega-6 and omega-3 fatty acids. This study builds on findings from earlier studies, but crucially now include controls for the feed intake effects to clarify the roles of hypoxia on the nutrient and intake mediated effects. As a result of these controls, it is now clearer that many of the phenomic responses to long-chain omega-3 by Atlantic salmon are nominal and are largely unaffected by challenging environmental conditions like hypoxia. The inclusion of a series of pair-fed treatments, matching the feed intake levels of corresponding hypoxic treatments, shows that the effects of n-3 LC-PUFA appear to be largely intake mediated effects for Atlantic salmon post-smolts.

Phycobiliprotein Peptide Extracts from Arthrospira platensis Ameliorate Nonalcoholic Fatty Liver Disease by Modulating Hepatic Lipid Profile and Strengthening Fat Mobilization.

Arthrospira platensis phycobiliprotein peptide extracts (PPEs) exhibit potential mitigative effects on hepatic steatosis. However, the precise role of PPEs in addressing high-fat-induced nonalcoholic fatty liver disease (NAFLD), as well as the underlying mechanism, remains to be elucidated. In this study, NAFLD was induced in rats through a high-fat diet (HFD), and the rats were subsequently treated with PPEs for a duration of 10 weeks. The outcomes of this investigation demonstrate that PPE supplementation leads to a reduction in body weight gain, a decrease in the accumulation of lipid droplets within the liver tissues, alterations in hepatic lipid profile, regulation of lipolysis-related gene expression within white adipose tissues and modulation of intestinal metabolites. Notably, PPE supplementation exhibits a potential to alleviate liver damage by manipulating neutral lipid metabolism and phospholipid metabolism. Additionally, PPEs appear to enhance fat mobilization by up-regulating the gene expression levels of key factors such as HSL, TGL, UCP1 and UCP2. Furthermore, PPEs impact intestinal metabolites by reducing the levels of long-chain fatty acids while concurrently increasing the levels of short-chain fatty acids. The findings from this study unveil the potential of PPE intervention in ameliorating NAFLD through the modulation of hepatic lipid profile and the reinforcement of the fat mobilization of intestinal metabolites. Thus, PPEs exhibit noteworthy therapeutic effects in the context of NAFLD.

The role of candidate transport proteins in β-cell long-chain fatty acid uptake: Where are we now?

Type 2 diabetes (T2D) in humans is typically preceded by elevated levels of circulatory long-chain free fatty acids (LC-FFA). These excess LC-FFA are widely thought to be taken up by pancreatic β-cells, contributing to their dysfunction and death during the development of T2D; a process that has been termed lipotoxicity. Depending on their degree of saturation and carbon chain length, LC-FFA can exert different effects on pancreatic β-cells viability and function in vitro. Long-chain saturated fatty acids (LC-SFA) are thought to be toxic, whereas monounsaturated fatty acids are not and may even offer protection against the toxic effects of LC-SFAs. However, the mechanism of LC-FFA uptake into pancreatic β-cells is poorly understood, partly because it has been an understudied area of research. Determining how LC-FFA are taken up into β-cells is crucial for later formulation of therapies to prevent potential cellular overload of LC-FFA, thereby slowing the onset of T2D. In this work, we detail more than 40 years of literature investigating the role of membrane-associated transport proteins in LC-FFA uptake. By focussing on what is known in other cell types, we highlight where we can extrapolate our current understanding of protein-mediated transport to β-cells and uncover where further understanding is required.

Obesity-induced dysregulation of skin-resident PPARγ+ Treg cells promotes IL-17A-mediated psoriatic inflammation

Obesity is a major risk factor for psoriasis, but how obesity disrupts the regulatory mechanisms that keep skin inflammation in check is unclear. Here, we found that skin was enriched with a unique population of CD4+Foxp3+ regulatory T (Treg) cells expressing the nuclear receptor peroxisome proliferation-activated receptor gamma (PPARγ). PPARγ drove a distinctive transcriptional program and functional suppression of IL-17A+ γδ Tcell-mediated psoriatic inflammation. Diet-induced obesity, however, resulted in a reduction of PPARγ+ skin Treg cells and a corresponding loss of control over IL-17A+ γδ Tcell-mediated inflammation. Mechanistically, PPARγ+ skin Treg cells preferentially took up elevated levels of long-chain free fatty acids in obese mice, which led to cellular lipotoxicity, oxidative stress, and mitochondrial dysfunction. Harnessing the anti-inflammatory properties of these PPARγ+ skin Treg cells could have therapeutic potential for obesity-associated inflammatory skin diseases.

Relationship of circulating levels of long-chain fatty acids to persistent organ failure in acute pancreatitis.

During acute pancreatitis (AP), free fatty acids (FFAs) are liberated from circulating triglycerides (TG) and injured adipocytes by pancreatic lipase. Circulating FFAs have been suspected as a source of systemic lipotoxicity in AP. However, assessment of FFAs is difficult and time-consuming, and little is known about relative levels of FFAs between patients with different severities of AP and controls. This study's aims were to assess early circulating levels of FFAs, (both saturated and unsaturated) in patients with AP vs. controls, and associations between FFA levels and AP severity. Serum samples from patients with AP were collected at enrollment (day 1 of hospital stay); serum samples were also collected from controls. FFAs including palmitic, palmitoleic, stearic, oleic, and linoleic acid were extracted and quantitated using gas chromatography separation. Severity of AP was determined by Revised Atlanta Classification. Differences in FFA levels and percentages of total FFAs were assessed between patients with AP and controls and patients with AP of different severity grades. A total of 93 patients with AP (48 female, 52%) and 29 controls (20 female, 69%) were enrolled. Of the patients with AP, 74 had mild/moderate and 19 had severe AP. Serum levels of all FFAs except stearic acid were significantly higher in patients with AP compared with controls. A strong and independent association between elevated palmitoleic acid levels and severe AP was found. Serum unsaturated FFA levels, specifically palmitoleic acid, appear to correlate with severe AP. These findings have potential clinical implications for targeted AP therapies.NEW & NOTEWORTHY Drivers of the inflammatory response in acute pancreatitis remain incompletely understood. Unsaturated fatty acids, specifically palmitoleic, appear to have an association with more severe acute pancreatitis. This finding presents a new clinical understanding of fatty acid toxicity and highlights a potential future target for treatment in severe acute pancreatitis.

Post-feeding Molecular Responses of Cobia (Rachycentron canadum): RNA-Sequencing as a Tool to Evaluate Postprandial Effects in Hepatic Lipid Metabolism.

We used transcriptome sequencing to investigate the hepatic postprandial responses of Rachycentron canadum (cobia), an important commercial fish species. In total, 150 cobia juveniles (50 per tank, triplicate) were fed ad libitum with a commercial diet for 7days, fasted for 24h, and fed for 10min. The liver was sampled 10min prior to feeding and 30min, 1, 2, 4, 8, 12, and 24h after the feeding event. Each sample was evaluated in terms of liver fatty acid profile and gene expression. Differential gene expressions were evaluated, focusing on fatty acid synthesis and oxidation pathways. In general, the liver fatty acid profile reflected diet composition. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) levels increased at 8 to 12h but decreased at 24h after the feeding event. A high number of differentially expressed genes (DEGs) were observed comparing fish that fasted for 8h with those fasted for 30min and 24h, while a reduced number of DEGs was observed comparing individuals who fasted for 30min compared with those who fasted for 24h. Similarly, the main differences in the expression of genes related to the fatty acid biosynthesis and oxidation pathways were noticed in individuals who fasted for 8h compared with those who fasted for 30min and 24h. The results suggested that the adequate time to sample the individuals ranged between 8 and 12h after the meal since, apparently, after 24h, differential gene expression was not necessarily influenced by food intake.

Metabolomics analysis of islet regeneration in partial pancreatectomy mice reveals increased levels of long-chain fatty acids and activated cAMP signaling pathway

Islet regeneration is a complex process involving multiple metabolic adaptions, but the specific characterization of the islet metabolome in relation to cell proliferation has not been established. This study aimed to investigate the metabolomic changes of regenerative islets from partial pancreatectomy (Ppx) mice and speculate underlying mechanisms. Islet samples were collected from C57/BL6 mice undergoing 70–80% Ppx or sham surgery, followed by analyses of glucose homeostasis, islet morphology, and untargeted metabolomics profiles using liquid chromatography-tandem mass spectrometry (LC-MS/MS). There is no difference in blood glucose and body weight between sham and Ppx mice. After surgery, the Ppx mice showed impaired glucose tolerance, increased Ki67 positive beta cells, and elevated beta-cell mass. LC-MS/MS analysis identified fourteen differentially changed metabolites in islets of Ppx mice, including long-chain fatty acids (e.g., docosahexaenoic acid) and amino acid derivatives (e.g., creatine). Pathway analysis based on the KEGG database revealed five significantly enriched signaling pathways including cAMP signaling pathway. Further immunostaining assay on pancreatic tissue sections showed the levels of p-CREB, a transcription factor downstream of cAMP, elevated in islets from Ppx mice. In conclusion, our results demonstrate that islet regeneration involves metabolic alterations in long-chain fatty acids and amino acid derivatives, as well as the activation of the cAMP signaling pathway.

Obesity-induced dysregulation of a unique subset of Tregs promotes skin inflammation

Abstract Obesity is associated with increased skin inflammation and is a major risk factor for psoriasis, raising the question of how obesity disrupts the regulatory mechanisms that keep skin inflammation in check at steady state. We found that skin was enriched with a unique subset of CD4 +Foxp3 +regulatory T cells (Tregs), which is critical to limit IL-17A-mediated psoriatic inflammation. Diet-induced obesity, however, resulted in a significant reduction of this subset of skin Tregs and a corresponding loss of control over IL-17A-mediated inflammation. Mechanistically, this specific skin Treg population preferentially took up elevated levels of long-chain saturated fatty acids during obesity, which led to cellular lipotoxicity and mitochondrial dysfunction. Harnessing the anti-inflammatory property of this unique subset of skin Tregs could have therapeutic potential for obesity-associated inflammatory skin diseases. Supported from grants from NIH/NIDDK (1R01DK128061), National Psoriasis Foundation, and Emory University Research Committee (URC).

Reproduction of Hatchery-Reared Pike-Perch (Sander lucioperca) Fed Diet with Low-Marine-Ingredients: Role of Dietary Fatty Acids

This research aimed to evaluate the reproductive potential of hatchery-reared (F1) pike-perch (Sander lucioperca) broodstock fed a commercial diet with low levels of long-chain polyunsaturated fatty acids (Lc-PUFA) and wild (F0) pike-perch broodstock fed forage fish. Reproductive parameters, including pseudogonadosomatic index (PGSI), egg size, latency time, hatching rate, embryo survival, and eggs’ fatty acid (FA) composition, as well as plasma sex hormone, glucose and immunoglobulin levels after hormone injection, were analyzed. The results showed low PGSI (10% in F1 vs. 14% in F0) and embryo survival (24% in F1 vs. 61% in F0) in F1 broodstock, but a satisfactory hatching rate (63% in F1 vs. 78% in F0) and larval size (4.6 mm in F1 vs. 4.7 mm in F0). A low arachidonic acid (ARA) percentage in F1 fish eggs (1.32%), along with increased immunoglobulin levels (17.31 g/L), suggests that immune system activation might have depleted the reserves of ARA in F1 fish, which is the key fatty acid for successful oocyte maturation. We assumed that the administration of more sustainable diets, based on terrestrial plant ingredients, is not inferior to higher-quality diets based on marine ingredients.

Interfacial compositions of fat globules modulate structural characteristics and lipolysis of its model emulsions during in-vitro digestion.

This study investigated whether milk fat globule membrane as an emulsifier could make fat easier for infants to digest. An emulsion was formed using the membrane material, where anhydrous milk fat was used as the core material, milk fat globule membrane polar lipid (MPL) as the emulsifier, and soybean phospholipid (PL) and milk protein concentrate (MPC) incorporated as control emulsifiers. Structural characterization, glyceride composition, and fatty acid release from emulsions by in vitro digestion were investigated. The average particle size at the end of intestinal digestion was in the order MPL < PL < MPC, with diameters of 3.41 ± 0.51 μm, 3.53 ± 0.47 μm, and 10.46 ± 2.33 μm respectively. Meanwhile, laser scanning confocal microscopy results also illustrated that MPL could reduce the degree of aggregation during digestion. The lipolysis degree of MPL emulsion was higher than that of PL and MPC emulsions. MPL not only released higher levels of long-chain fatty acids, such as C18:1, C18:2, C18:3, which are of great significance for infant growth and development, but also released increased levels of C20:4 (arachidonic acid) and C22:6 (docosahexaenoic acid) than PL and MPC emulsions did. Fat droplets enveloped by milk fat globule MPLs were easier to digest and are therefore more suitable for infant formula. © 2023 Society of Chemical Industry.

Long-Chain Polyunsaturated Fatty Acid Levels in Formulae Influence Deposition of Docosahexaenoic Acid and Arachidonic Acid in Brain and Red Blood Cells of Artificially Reared Neonatal Rats

We studied the effects of dietary long-chain polyunsaturated fatty acids (PUFA) on the fatty acid composition of the brain and red blood cells in gastrostomized rat pups reared artificially from postnatal Days 5–18. These pups were fed rat milk substitutes in which the fat comprised 10% linoleic acid and 1% α-linolenic acid and, using a 3 × 3 factorial design, one of three levels of both arachidonic acid (AA) and docosahexaenoic acid (DHA) supplied as single cell microbial oils (0.0, 0.4 and 2.4% fatty acids). A tenth group was reared by nursing dams. The fatty acid composition of the phosphatidylethanolamine (PE) and phosphatidylserine/phosphatidylinositol (PS/PI) phospholipids in the brain and red blood cells on Day 18 reflected the dietary composition in that pups receiving long-chain supplementation of each had higher levels of the supplemented PUFA, but lower levels of the other, relative to unsupplemented groups. In contrast to these results, there were few changes in the brain in phosphatidylcholine (PC) phospholipids whereas, in the red blood cells, changes in PC were similar to those in PE and PS/PI. Regression analyses showed that DHA levels in the brain correlated more closely with those of the red blood cells than did AA levels. The results of this study indicate that, although supplementation of formula with AA or DHA during the period of rapid brain development in rats increases deposition of the long-chain PUFA in the developing tissues, each also affects the levels of the other.

Lacticaseibacillus casei decrease long-chain fatty acids and most substances in an experimental model of intestinal mucositis.

To evaluate the long-chain fatty acid and major compounds levels in the feces after prophylactic oral use of Lacticaseibacillus casei in an experimental model of intestinal mucositis. Fifteen Swiss mice were randomly divided into three groups (n=5/group): The negative or positive control groups (n = 5) received saline orally for 18 days and an the intraperitoneal (i.p.) of saline or 5 Fluorouracil (450 mg/kg) in 15th day, respectability. L. casei group received oral concentration of L. casei (1x109 CFU/mL) for 18 days, the i.p. injection of 5-fluorouracil (450 mg/kg) in 15th days. Tissue samples from colon and each small intestine segment were collected for histopathological analysis. Stool samples were collected. Fecal composition of long-chain fatty acids and sterols were analysed by gas chromatography-mass spectrometry on the 15th and the 18th day. The mucosa layer of all small intestine segments of animals from L. casei showed well preserved epithelium and glands, without necrosis signs, but Goblet cells number decreased. Several long-chain fatty acids and sterols have been identified before and after in the groups. L. casei administration after 5-FU treatment reduced concentrations of linoleic acid (18:2) (p < 0.001) and oleic acid (18:1) (p < 0.001) in feces. L. casei prevented the mucosal damage associated with 5-FU-induced intestinal mucositis reduced long-chain fatty acid levels in the feces.

Effects of Tea Polyphenol and Its Combination with Other Antioxidants Added during the Extraction Process on Oxidative Stability of Antarctic Krill (Euphausia superba) Oil

Antarctic krill (Euphausia superba) oil contains high levels of marine omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In industrial production, krill oil is usually extracted from krill meals by using ethanol as a solvent. Water in the krill meal can be easily extracted by using ethanol as an extraction solvent. During the extraction process, the EPA and DHA are more easily oxidized and degraded when water exists in the ethanol extract of krill oil. Based on the analysis of peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), fatty acid composition, and lipid class composition, the present study indicated that the composite antioxidants (TP-TPP) consist of tea polyphenol (TP) and tea polyphenol palmitate (TPP) had an excellent antioxidant effect. By contrast, adding TP-TPP into ethanol solvent during the extraction process is more effective than adding TP-TPP into krill oil after the extraction process.

Stearate-derived very long-chain fatty acids are indispensable to tumor growth.

Reprogramming of lipid metabolism is emerging as a hallmark of cancer, yet involvement of specific fatty acids (FA) species and related enzymes in tumorigenesis remains unclear. While previous studies have focused on involvement of long-chain fatty acids (LCFAs) including palmitate in cancer, little attention has been paid to the role of very long-chain fatty acids (VLCFAs). Here, we show that depletion of acetyl-CoA carboxylase (ACC1), a critical enzyme involved in the biosynthesis of fatty acids, inhibits both de novo synthesis and elongation of VLCFAs in human cancer cells. ACC1 depletion markedly reduces cellular VLCFA but only marginally influences LCFA levels, including palmitate that can be nutritionally available. Therefore, tumor growth is specifically susceptible to regulation of VLCFAs. We further demonstrate that VLCFA deficiency results in a significant decrease in ceramides as well as downstream glucosylceramides and sphingomyelins, which impairs mitochondrial morphology and renders cancer cells sensitive to oxidative stress and cell death. Taken together, our study highlights that VLCFAs are selectively required for cancer cell survival and reveals a potential strategy to suppress tumor growth.

Effects of 6-O-α-maltosyl-β cyclodextrin on lipid metabolism in Npc1-deficient Chinese hamster ovary cells.

Niemann-Pick disease Type C (NPC) is a lysosomal storage disorder caused by mutation of the NPC1/NPC2 genes, which ultimately results in the accumulation of unesterified cholesterol (UEC) in lysosomes, thereby inducing symptoms such as progressive neurodegeneration and hepatosplenomegaly. This study determines the effects of 6-O-α-maltosyl-β cyclodextrin (Mal-βCD) on lipid levels and synthesis in Npc1-deficient (Npc1-KO cells) and vehicle CHO cells. Compared to vehicle cells, Npc1-KO cells exhibited high level of UEC, and low levels of esterified cholesterols (ECs) and long-chain fatty acids (LCFAs). The difference in lipid levels between Npc1-KO and CHO cells was largely ameliorated by Mal-βCD administration. Moreover, the effects of Mal-βCD were reproduced in the lysosomes prepared from Npc1-KO cells. Stable isotope tracer analysis with extracellular addition of D4-deuterated palmitic acid (D4-PA) to Npc1-KO cells increased the synthesis of D4-deuterated LCFAs (D4-LCFAs) and D4-deuterated ECs (D4-ECs) in a Mal-βCD-dependent manner. Simultaneous addition of D6-deuterated UEC (D6-UEC) and D4-PA promoted the Mal-βCD-dependent synthesis of D6-/D4-ECs, consisting of D6-UEC and D4-PA, D4-deuterated stearic acid, or D4-deuterated myristic acid, in Npc1-KO cells. These results suggest that Mal-βCD helps to maintain normal lipid metabolism by restoring balance among UEC, ECs, and LCFAs through acting on behalf of NPC1 in Npc1-KO cells and may therefore be useful in designing effective therapies for NPC.

Can Artemia franciscana produce essential fatty acids? Unveiling the capacity of brine shrimp to biosynthesise long-chain polyunsaturated fatty acids

Artemia nauplii are widely used as live preys for feeding early life-cycle stages of marine finfish and shrimp. However, a major drawback associated to using Artemia is their deficient nutritional value for marine larvae that is primarily linked to suboptimal levels of long-chain polyunsaturated fatty acids (LC-PUFA), essential nutrients that guarantee normal growth and development of animals. While common marine hatchery procedures involve enrichment processes to address such nutritional deficiencies, the specific drivers accounting for the naturally occurring variability in LC-PUFA of Artemia are largely unknown. Biosynthesis, along diet, is one of the main factors determining the LC-PUFA profiles in animals and it depends upon the repertoire and function of fatty acyl elongases and desaturases existing in a particular species. The aim of this study was the molecular and functional characterisation of all elongase and desaturase enzymes involved in the LC-PUFA biosynthesis from Artemia franciscana, arguably the most commonly used Artemia species. Seven out of eight elongases (termed “Elo1-8”) found in A. franciscana had distinctive features of LC-PUFA biosynthesising elongases. Consistently, functional assays showed these elongases were able to elongate multiple substrates and thus enabling A. franciscana to perform all elongation reactions of the LC-PUFA biosynthetic pathways. While all seven functionally characterised elongases from A. franciscana showed activity towards multiple substrates including C18 to C22 polyunsaturated fatty acids, particularly high activity was detected for the Elovl8 orthologue (termed herein as “Elo7”). Additionally, A. franciscana was found to have three genes of the so-called “first” desaturases (“Des1-3”), and lack other key LC-PUFA biosynthesising desaturases such as methyl-end and front-end desaturases. Two desaturases have the expected ∆9 desaturase activity, whereas a third one showed ∆12 activity. Neither methyl-end nor front-end desaturases were found in A. franciscana. In conclusion, this study demonstrated that A. franciscana has high elongation capacity but its overall LC-PUFA biosynthesis can be regarded as limited due to the lack of an adequate complement of fatty acyl desaturases in its genome.

Genes regulating levels of ω-3 long-chain polyunsaturated fatty acids are associated with alcohol use disorder and consumption, and broader externalizing behavior in humans.

Individual variation in the physiological response to alcohol is predictive of an individual's likelihood to develop alcohol use disorder (AUD). Evidence from diverse model organisms indicates that the levels of long-chain polyunsaturated omega-3 fatty acids (ω-3 LC-PUFAs) can modulate the behavioral response to ethanol and therefore may impact the propensity to develop AUD. While most ω-3 LC-PUFAs come from diet, humans can produce these fatty acids from shorter chain precursors through a series of enzymatic steps. Natural variation in the genes encoding these enzymes has been shown to affect ω-3 LC-PUFA levels. We hypothesized that variation in these genes could contribute to the susceptibility to develop AUD. We identified nine genes (FADS1, FADS2, FADS3, ELOVL2, GCKR, ELOVL1, ACOX1, APOE, and PPARA) that are required to generate ω-3 LC-PUFAs and/or have been shown or predicted to affect ω-3 LC-PUFA levels. Using both set-based and gene-based analyses we examined their association with AUD and two AUD-related phenotypes, alcohol consumption, and an externalizing phenotype. We found that the set of nine genes is associated with all three phenotypes. When examined individually, GCKR, FADS2, and ACOX1 showed significant association signals with alcohol consumption. GCKR was significantly associated with AUD. ELOVL1 and APOE were associated with externalizing. Taken together with observations that dietary ω-3 LC-PUFAs can affect ethanol-related phenotypes, this work suggests that these fatty acids provide a link between the environmental and genetic influences on the risk of developing AUD.

The Fish Oil to Reduce Tobacco Use iN Expectant mothers (FORTUNE) feasibility trial

Three small clinical trials have suggested that supplementation with n-3 long-chain polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid) found in fish oils may reduce nicotine cravings and at higher doses reduce cigarette consumption. Pregnant women who smoke have fewer pharmacologic options to aid them with smoking cessation. Although n-3 long-chain polyunsaturated fatty acid supplementation has been studied in pregnancy, few studies have evaluated doses of ≥4 g per day, and no previous studies have selectively enrolled pregnant women who smoke. High-dose n-3 long-chain polyunsaturated fatty acids may aid cessation but could be poorly tolerated in pregnant women who smoke because of gastrointestinal side effects. We conducted a feasibility trial to determine the tolerability of high-dose n-3 long-chain polyunsaturated fatty acid supplementation in pregnant women who smoked. We hypothesized that n-3 long-chain polyunsaturated fatty acid doses of 4.2 g a day would be well-tolerated relative to an olive oil placebo. We assessed red blood cell phospholipid membrane concentrations at baseline and end of therapy (4 weeks) and piloted outcomes for a future efficacy trial of n-3 long-chain polyunsaturated fatty acid supplementation for smoking cessation in pregnancy. We recruited 28 pregnant women between the gestational ages of 6 and 36 weeks who reported daily cigarette smoking and were motivated to quit to participate in a double-blind placebo-controlled randomized feasibility trial of 4.2 g per day of n-3 long-chain polyunsaturated fatty acid supplementation. Participants reported cigarettes per day, completed the Fagerström Test for Cigarette Dependence, and provided blood, urine, and exhaled CO samples. We used repeated-measures analysis of variance to pilot analyses of changes in cigarettes per day and Fagerström Test for Cigarette Dependence scores. At baseline, red blood cell membrane eicosapentaenoic acid concentrations were negatively correlated with cigarettes per day (r=-0.44; P=.04). By 4 weeks, circulating n-3 long-chain polyunsaturated fatty acid levels increased by 18% in the n-3 long-chain polyunsaturated fatty acid supplementation arm vs a decrease of 3% in the placebo arm. Occurrence of gastrointestinal side effects such as burping, heartburn, diarrhea, abdominal pain, or nausea did not differ statistically between study arms. At 4 weeks, participants allocated to the n-3 long-chain polyunsaturated fatty acids arm reported a median of 3 cigarettes per day (interquartile range, 1-8) vs 7 cigarettes per day (interquartile range, 1-14) in the placebo arm, which was not statistically significant (P=.99). Participants allocated to the n-3 long-chain polyunsaturated fatty acids arm had a decrease of 1 (interquartile range, 0-1) on the Fagerström Test for Cigarette Dependence score vs 0 (interquartile range, 0-0) for placebo (P=.46). High-dose n-3 long-chain polyunsaturated fatty acids may be tolerated in pregnant women who smoke; however, there was a high level of participant dropout, with more participants allocated to the fish oil arm becoming lost to follow-up. These results will inform the design of a future large-scale randomized controlled trial to test the impact of fish oil supplements on smoking cessation in pregnancy.