Association between fish and shellfish consumption, n-3 polyunsaturated fatty acids, and gastric cancer risk: the Japan Public Health Center-based Prospective Study

PURPOSE

Fish and shellfish consumption is suggested to be a cancer-protective factor. However, studies investigating this association for gastric cancer, especially considering Helicobacter pylori (H. pylori) and atrophic gastritis (AG), are limited. We investigated gastric cancer risk associated with fish, shellfish, and n-3 polyunsaturated fatty acids (n-3 PUFAs) consumption among Japanese adults.

METHODS

90,504 subjects enrolled in the Japan Public Health Center-based Prospective Study (JPHC Study) were followed until December 2013. Dietary intake data were collected using a food frequency questionnaire. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for gastric cancer risk associated with fish and shellfish consumption and marine n-3 PUFAs (sum of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)) using Cox proportional hazards models. Among those with avaliable data, we conducted a subgroup analysis taking H. pylori infection and AG status  into consideration.

RESULTS

There were 2,701 gastric cancer cases during an average of 15 years of follow-up. We observed an increased gastric cancer risk for salted fish consumption for men [HR for fifth quintile versus first quintile 1.43 (95% CI 1.18-1.75)] and for women [HR 1.33 (95% CI 1.00-1.77)]. We observed a weak risk reduction trend for women as the intake of marine n-3 PUFAs increased (p-trend:0.07). When we included H. pylori infection and atrophic gastritis status in the analysis, the associations diminished.

CONCLUSION

Our results suggest that salted fish increases gastric cancer risk for men and women, while marine n-3 PUFAs marginally decreases this risk among women in Japan.

Thermodynamic Analysis to Evaluate the Effect of Diet on Brain Glucose Metabolism: The Case of Fish Oil

Inefficient glucose metabolism and decreased ATP production in the brain are linked to ageing, cognitive decline, and neurodegenerative diseases (NDDs). This study employed thermodynamic analysis to assess the effect of fish oil supplementation on glucose metabolism in ageing brains. Data from previous studies on glucose metabolism in the aged human brain and grey mouse lemur brains were examined. The results demonstrated that Omega-3 fish oil supplementation in grey mouse lemurs increased entropy generation and decreased Gibbs free energy across all brain regions. Specifically, there was a 47.4% increase in entropy generation and a 47.4 decrease in Gibbs free energy in the whole brain, indicating improved metabolic efficiency. In the human model, looking at the specific brain regions, supplementation with Omega-3 polyunsaturated fatty acids (n-3 PUFAs) reduced the entropy generation difference between elderly and young individuals in the cerebellum and particular parts of the brain cortex, namely the anterior cingulate and occipital lobe, with 100%, 14.29%, and 20% reductions, respectively. The Gibbs free energy difference was reduced only in the anterior cingulate by 60.64%. This research underscores that the application of thermodynamics is a comparable and powerful tool in comprehending the dynamics and metabolic intricacies within the brain.

Profiles of Serum Fatty Acids in Healthy Women on Different Types of Vegetarian Diets

BACKGROUND

Plant-based dietary patterns are a source of different amounts and proportions of fatty acids (FAs) from those in traditional diets. Information about the full FAs profile provided by plant-based diets is widely lacking. The aim of this study was to present the exact serum profiles of FAs among people on a plant-based diet compared with omnivorous subjects.

METHODS

FAs compositions and inflammation statuses (based on serum C-reactive protein (CRP) levels) were studied in serum samples obtained from 102 female volunteers (divided into four groups: vegans, vegetarians, pescatarians, and omnivores). The quality of the volunteers' diets was assessed based on seven-day dietary records.

RESULTS

Both vegans and vegetarians had lower total n-3 PUFAs, EPA, and DHA serum levels than omnivores. Decreased levels of these FAs presumably did not cause inflammation in vegetarians and vegans, as vegetarians had similar serum levels of CRP compared to omnivores, and vegans had even lower levels.

CONCLUSION

The analysis of serum FAs and CRP levels in vegetarians and vegans suggests that factors other than diet alone influence inflammation and overall health status. Further research on long-term plant-based diet users is needed to better understand this issue, and supplementation with EPA and DHA is worth considering in vegans and vegetarians.

n-3 PUFAs Show Promise as Adjuvants in Chemotherapy, Enhancing their Efficacy while Safeguarding Hematopoiesis and Promoting Bone Generation

Cancer ranks as the second leading cause of mortality in high-income countries, underscoring the critical need for effective therapeutic strategies. One prominent approach, chemotherapy, is widely employed for treating solid tumors. However, the significant adverse effects associated with chemotherapy, notably myeloablation and osteonecrosis, impart considerable challenges by compromising immune function and diminishing patients' quality of life. Furthermore, the emergence of chemotherapy resistance poses a formidable hurdle in achieving successful cancer treatment outcomes. In this context, the focus is on exploring alternative approaches to enhance the efficacy of cancer treatment and mitigate its adverse consequences. Among these approaches, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), two n-3 polyunsaturated fatty acids (PUFAs), have garnered substantial interest. These PUFAs exhibit the potential to influence membrane lipid composition and modulate critical gene expressions associated with cancer, such as Bcl-2, PI3K, NF-κB, and phosphorylated Akt, thereby potentially reducing cancer risk. Moreover, emerging evidence highlights their ability to augment chemotherapy efficacy, particularly in drug-resistant cancer cells. Importantly, both preclinical and clinical investigations have provided compelling evidence supporting the protective effects of n-3 PUFAs on healthy cells. Leveraging these findings, there has been growing attention on the exploration of n-3 PUFAs as adjuvants to chemotherapy. This strategic approach holds promise in mitigating the adverse effects linked to chemotherapy, notably myeloablation and osteonecrosis, while simultaneously enhancing its effectiveness in combating cancer. This comprehensive review delves into the multifaceted attributes of n-3 PUFAs, encompassing their cytotoxic properties, potential as chemopreventive agents, and their prospective role in ameliorating the adverse effects commonly associated with chemotherapy, with a particular emphasis on myeloablation and osteonecrosis. By elucidating the intricate interplay between n-3 PUFAs and cancer treatment paradigms, this review contributes to the expanding body of knowledge aimed at refining cancer therapeutic strategies and enhancing patient outcomes.

The Role of Marine n-3 Polyunsaturated Fatty Acids in Inflammatory-Based Disease: The Case of Rheumatoid Arthritis

Inflammation is a conserved process that involves the activation of immune and non-immune cells aimed at protecting the host from bacteria, viruses, toxins and injury. However, unresolved inflammation and the permanent release of pro-inflammatory mediators are responsible for the promotion of a condition called "low-grade systemic chronic inflammation", which is characterized by tissue and organ damage, metabolic changes and an increased susceptibility to non-communicable diseases. Several studies have demonstrated that different dietary components may influence modifiable risk factors for diverse chronic human pathologies. Marine n-3 polyunsaturated fatty acids (n-3 PUFAs), mainly eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), are well-recognized anti-inflammatory and immunomodulatory agents that are able to influence many aspects of the inflammatory process. The aim of this article is to review the recent literature that relates to the modulation of human disease, such as rheumatoid arthritis, by n-3 PUFAs.

Sex differences in erythrocyte fatty acid composition of first-diagnosed, drug-naïve patients with major depressive disorders

Background: Since depression, sex hormones, and fatty acid status are interrelated, it is important to understand their relationships. In this study, we aimed to investigate sex differences in erythrocyte membrane fatty acid composition among first-diagnosed, drug-naïve patients with major depressive disorders. Methods: The study included 139 individuals with first-diagnosed, drug-naïve depression (male/female = 48/91) and 55 healthy controls (male/female = 24/31). The levels of erythrocyte membrane fatty acids were analyzed to compare the difference between males and females in both patients with depression and healthy controls, as well as to study their correlation with depressive symptoms. Results: In first-diagnosed, drug-naïve patients with major depressive disorders, sex disparities were observed in the levels of erythrocyte saturated fatty acids (SFAs) and n-6 PUFAs (such as C18:0, C20:4n6 and C22:4n6), where higher levels evident in females compared to in males. We found a noteworthy correlation between fatty acid levels and depressive symptoms, in which there is a significant association between female patients and depression but a weaker association between male patients and depression. Conclusion: Our findings demonstrate higher levels of n-6 PUFAs and SFAs in female patients with depression. The relationship between fatty acid composition and depressive symptoms was more prominent in females than males. These findings highlight the significance of considering sex as a crucial and interconnected factor in future investigations and potential adjunctive treatment for mood disorders by targeting fatty acid metabolism.

Eicosapentaenoic Acid Influences the Lipid Profile of an In Vitro Psoriatic Skin Model Produced with T Cells

Psoriasis is a skin disease characterized by epidermal hyperplasia and an inappropriate activation of the adaptive immunity. A dysregulation of the skin's lipid mediators is reported in the disease with a predominance of the inflammatory cascade derived from n-6 polyunsaturated fatty acids (n-6 PUFAs). Bioactive lipid mediators derived from arachidonic acid (AA) are involved in the inflammatory functions of T cells in psoriasis, whereas n-3 PUFAs' derivatives are anti-inflammatory metabolites. Here, we sought to evaluate the influence of a supplementation of the culture media with eicosapentaenoic acid (EPA) on the lipid profile of a psoriatic skin model produced with polarized T cells. Healthy and psoriatic skin substitutes were produced following the auto-assembly technique. Psoriatic skin substitutes produced with or without T cells presented increased epidermal and dermal linolenic acid (LA) and AA levels. N-6 PUFA lipid mediators were strongly measured in psoriatic substitutes, namely, 13-hydroxyoctadecadienoic acid (13-HODE), prostaglandin E2 (PGE2) and 12-hydroxyeicosatetraenoic acid (12-HETE). The added EPA elevated the amounts of EPA, n-3 docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) in the epidermal and dermal phospholipids. The EPA supplementation balanced the production of epidermal lipid mediators, with an increase in prostaglandin E3 (PGE3), 12-hydroxyeicosapentaenoic acid (12-HEPE) and N-eicosapentaenoyl-ethanolamine (EPEA) levels. These findings show that EPA modulates the lipid composition of psoriatic skin substitutes by encouraging the return to a cutaneous homeostatic state.

The association between n-3 polyunsaturated fatty acid intakes and asthma in US children and adolescents: A cross-sectional study from NHANES

BACKGROUND

Asthma is an inflammatory disease. The potential of n-3 polyunsaturated fatty acids (PUFAs) to alleviate asthma symptoms through their anti-inflammatory effects and immune modulation has been explored. However, the precise role of dietary n-3 PUFAs in childhood and adolescent asthma remains unclear.

OBJECTIVE

This study aimed to evaluate the association between dietary n-3 PUFAs intake and asthma in children and adolescents in the United States.

METHODS

We conducted a cross-sectional analysis of 8543 children and adolescents from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2020 by adjusting for covariates and using multivariate logistic regression, restricted cubic spline, threshold effects, and subgroup analyses.

RESULTS

Among 8354 participants, 1456 (16.5%) self-reported diagnosis of asthma by a healthcare provider. After adjusting for potential confounding factors, compared with individuals in the lowest n-3 PUFA consumption group (T1, <26.07 mg/kg/day), the adjusted odds ratio (OR) for asthma was 0.71 (95% CI: 0.6-0.84, p < .001) in the second group (T2, 26.07-48.93 mg/kg/day) and 0.58 (95% CI: 0.47-0.73, p < .001) in the third group (T3, >48.93 mg/kg/day). Furthermore, a nonlinear (L-shaped) relationship was observed between n-3 PUFA intake and asthma (p = .009), with subgroup and sensitivity analyses confirming the stability of the results. In the threshold analysis, a critical turning point was observed at approximately 59.0 mg/kg/day (OR = 0.984, 95% CI: 0.977-0.991, p < .001).

CONCLUSION

Dietary intake of n-3 PUFAs exhibited an L-shaped relationship with asthma in children and adolescents in the United States, with a critical turning point observed at approximately 59.0 mg/kg/day.

Eicosapentaenoic Acid Induces the Inhibition of Adipogenesis by Reducing the Effect of PPARγ Activator and Mediating PKA Activation and Increased COX-2 Expression in 3T3-L1 Cells at the Differentiation Stage

Obesity has received increasing attention in recent years because it is a factor in the development of non-communicable diseases. The current study aimed to analyze how representative fatty acids (FAs) such as palmitic acid, stearic acid, oleic acid, α-linolenic acid (ALA), and eicosapentaenoic acid (EPA) affected adipogenesis when/if introduced at the differentiation stage of 3T3-L1 cell culture. These FAs are assumed to be potentially relevant to the progression or prevention of obesity. EPA added during the differentiation stage reduced intracellular triacylglycerol (TAG) accumulation, as well as the expression of the established adipocyte-specific marker genes, during the maturation stage. However, no other FAs inhibited intracellular TAG accumulation. Coexistence of Δ12-prostaglandin J2, a peroxisome proliferator-activated receptor γ activator, with EPA during the differentiation stage partially attenuated the inhibitory effect of EPA on intracellular TAG accumulation. EPA increased cyclooxygenase-2 (COX-2) expression and protein kinase A (PKA) activity at the differentiation stage, which could explain the inhibitory actions of EPA. Taken together, exposure of preadipocytes to EPA only during the differentiation stage may be sufficient to finally reduce the mass of white adipose tissue through increasing COX-2 expression and PKA activity.

Omega-3 Polyunsaturated Fatty Acid Eicosapentaenoic Acid or Docosahexaenoic Acid Improved Ageing-Associated Cognitive Decline by Regulating Glial Polarization

Neuroinflammation induced by microglial and astrocyte polarizations may contribute to neurodegeneration and cognitive impairment. Omega (n)-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory and neuroprotective effects, but conflicting results were reported after different n-3 PUFA treatments. This study examined both the change in glial polarizations in ageing rats and the differential effects of two omega-3 PUFAs. The results showed that both PUFAs improved spatial memory in ageing rats, with docosahexaenoic acid (DHA) being more effective than eicosapentaenoic acid (EPA). The imbalance between microglial M1/M2 polarizations, such as up-regulating ionized calcium binding adaptor molecule 1 (IBA1) and down-regulating CD206 and arginase-1 (ARG-1) was reversed in the hippocampus by both n-3 PUFAs, while the DHA effect on CD206 was stronger. Astrocyte A1 polarization presented increasing S100B and C3 but decreasing A2 parameter S100A10 in the ageing brain, which were restored by both PUFAs, while DHA was more effective on S100A10 than EPA. Consistent with microglial M1 activation, the concentration of pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were significantly increased, which were attenuated by DHA, while EPA only suppressed IL-6. In correlation with astrocyte changes, brain-derived neurotrophic factor precursor was increased in ageing rats, which was more powerfully down-regulated by DHA than EPA. In summary, enhanced microglial M1 and astrocytic A1 polarizations may contribute to increased brain pro-inflammatory cytokines, while DHA was more powerful than EPA to alleviate ageing-associated neuroimmunological changes, thereby better-improving memory impairment.

Yolk Fatty Acid Content, Lipid Health Indices, and Oxidative Stability in Eggs of Slow-Growing Sasso Chickens Fed on Flaxseed Supplemented with Plant Polyphenol Extracts

Previous attempts to increase the level of flaxseed in hens' diet for the production of n-3 polyunsaturated fatty acids (n-3 PUFAs)-enriched eggs have been commonly associated with undesirable effects on production efficiency, lipid health indices, and oxidative stability of eggs, requiring adequate research attention. This study investigated the effects of feeding a moderate level of flaxseed (FS) and plant polyphenol extracts (PPEs) on fatty acid content, oxidative stability, and lipid health indices in eggs of slow-growing Sasso T451A laying hens. One hundred and five hens were assigned to five groups (seven replicates of three) and fed on FS (75 g flaxseed and no antioxidants), VE8 (75 g flaxseed and 800 mg vitamin E), TS8 (75 g flaxseed and 800 mg Thymus schimperi), DA8 (75 g flaxseed and 800 mg Dodonaea angustifolia), and CD8 (75 g flaxseed and 800 mg Curcuma domestica) extract per kg diets. The egg yolk content of eicosapentaenoic acid (EPA, C20:5 n-3) in the DA8, TS8, and CD8 diets and docosahexaenoic acid (DHA, C22:6 n-3) in TS8 and CD8 diets significantly (p < 0.05) increased compared with the FS diet. The FS diet significantly increased the malondialdehyde (MDA) content in egg yolks, whereas the TS8 diet decreased it by 67% (p < 0.05). Little difference was observed in yolk fatty acid content between cooked and raw eggs. Production of n-3 PUFA-enriched eggs with favorable lipid health indices was possible through inclusion of PPEs extracted from local plant species grown in Ethiopia and a moderate dose of flaxseed in the diet of laying hens.

Identification of Optimal Reference Genes for qRT-PCR Normalization for Physical Activity Intervention and Omega-3 Fatty Acids Supplementation in Humans

The quantitative polymerase chain reaction (qRT-PCR) technique gives promising opportunities to detect and quantify RNA targets and is commonly used in many research fields. This study aimed to identify suitable reference genes for physical exercise and omega-3 fatty acids supplementation intervention. Forty healthy, physically active men were exposed to a 12-week eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation and standardized endurance training protocol. Blood samples were collected before and after the intervention and mRNA levels of six potential reference genes were tested in the leukocytes of 18 eligible participants using the qRT-PCR method: GAPDH (Glyceraldehyde-3-phosphate dehydrogenase), ACTB (Beta actin), TUBB (Tubulin Beta Class I), RPS18 (Ribosomal Protein S18), UBE2D2 (Ubiquitin-conjugating enzyme E2 D2), and HPRT1 (Hypoxanthine Phosphoribosyltransferase 1). The raw quantification cycle (Cq) values were then analyzed using RefFinder, an online tool that incorporates four different algorithms: NormFinder, geNorm, BestKeeper, and the comparative delta-Ct method. Delta-Ct, NormFinder, BestKeeper, and RefFinder comprehensive ranking have found GAPDH to be the most stably expressed gene. geNorm has identified TUBB and HPRT as the most stable genes. All algorithms have found ACTB to be the least stably expressed gene. A combination of the three most stably expressed genes, namely GAPDH, TUBB, and HPRT, is suggested for obtaining the most reliable results.

Partial replacement of high-fat diet with n-3 PUFAs enhanced beef tallow attenuates dyslipidemia and endoplasmic reticulum stress in tunicamycin-injected rats

Introduction

Metabolic syndrome (MetS) is considered as a complex, intertwined multiple risk factors that directly increase the risk of various metabolic diseases, especially cardiovascular atherosclerotic diseases and diabetes mellitus type 2. While lifestyle changes, including dietary intervention are effective in mitigating or preventing MetS, there are no specific therapies against MetS. Typical western diets comprise of high saturated fatty acid, cholesterol, and simple sugar; consequently their consumption may increase the potential pathological developmental risk of MetS. Partial replacement of dietary fatty acids with polyunsaturated fatty acids (PUFAs) is widely recommended measure to manage MetS-related disorders.

Methods

In the present study, we used rat model to investigate the role of n-3 PUFA enriched beef tallows (BT) on MetS and tunicamycin (TM)-induced endoplasmic reticulum (ER) stress, by partially replacing dietary fat (lard) with equal amounts of two different BTs; regular BT or n-3 PUFA-enriched BT. The experimental rats were randomly assigned to three different dietary groups (n = 16 per group): (1) high-fat and high-cholesterol diet (HFCD); (2) HFCD partially replaced with regular BT (HFCD + BT1); (3) HFCD partially replaced with n-3 enhanced BT (w/w) (HFCD + BT2). After 10 weeks of dietary intervention, each experimental rodent was intraperitoneally injected with either phosphate-buffered saline or 1 mg/kg body weight of TM.

Results

HFCD + BT2 showed improved dyslipidemia before TM injection, and increased serum high-density lipoprotein cholesterol (HDL-C) levels after TM injection. BT replacement groups had significantly reduced hepatic triglyceride (TG) levels, and decreased total cholesterol (TC) and TG levels in epididymal adipose tissue (EAT). Furthermore, BT replacement remarkably attenuated TM-induced unfolded protein responses (UPRs) in liver, showing reduced ER stress, with BT2 being more effective in the EAT.

Discussion

Therefore, our findings suggest that partially replacing dietary fats with n-3 PUFA to lower the ratio of n-6/n-3 PUFAs is beneficial in preventing pathological features of MetS by alleviating HFCD- and/or TM-induced dyslipidemia and ER stress.

Dietary n-3 and n-6 polyunsaturated fatty acids differentially modulate the adiponectin and leptinmediated major signaling pathways in visceral and subcutaneous white adipose tissue in high fat diet induced obesity in Wistar rats

Obesity is a chronic metabolic disease that involves excessive accumulation of fat in white adipose tissue (WAT). Apart from storing excess fats, WAT also serves as an important endocrine organ secreting adipocytokines such as adiponectin and leptin. Adiponectin and leptin bind to their transmembrane receptors adiponectin receptor 1 (AdipoR1)/adiponectin receptor 2 (AdipoR2) and Ob-R, respectively, and mediate their effect on metabolism by regulating multiple downstream targets. Dietary fat is considered the main culprit behind obesity development. Numerous preclinical studies have highlighted role of essential polyunsaturated fatty acids (PUFAs), particularly n-3 PUFAs, in prevention of obesity. Despite emerging data, there still is no clear understanding of the mechanism of action of n-3 PUFAs and n-6 PUFAs on adipose tissue function in two functionally and anatomically different depots of WAT: visceral and subcutaneous. We designed this study using a high fat diet (HFD) fed rodent model of obesity to test our hypothesis that n-3 and n-6 PUFAs possibly differentially modulate adipokine secretion and downstream metabolic pathways such as peroxisome proliferator-activated receptor-γ (PPAR-γ), protein kinase B (AKT)-forkhead box O1 (FOXO1), and Janus kinase-signal transducer and activator of transcription in obesity. The results of the current study showed that n-3 PUFAs upregulate the expression of AdipoR1/R2 and ameliorate the effects of HFD by modulating adipogenesis via PPAR-γ and by improving glucose tolerance and lipid metabolism via AKT-FOXO1 axis in fish oil fed rats. However, n-6 PUFAs did not show any remarkable change compared with HFD fed animals. Our study highlights that n-3 PUFAs modulate expression of various targets in adiponectin and leptin signaling cascade, bringing about an overall reduction in obesity and improvement in adipose tissue function in HFD induced obesity.

Omega-3 Polyunsaturated Fatty Acids (n-3 PUFAs) for Immunomodulation in COVID-19 Related Acute Respiratory Distress Syndrome (ARDS)

Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), might be complicated by Acute Respiratory Distress Syndrome (ARDS) caused by severe lung damage. It is relevant to find treatments for COVID-19-related ARDS. Currently, DHA and EPA n-3 PUFAs, known for their immunomodulatory activities, have been proposed for COVID-19 management, and clinical trials are ongoing. Here, examining COVID-19-related ARDS immunopathology, we reference in vitro and in vivo studies, indicating n-3 PUFA immunomodulation on lung microenvironment (bronchial and alveolar epithelial cells, macrophages, infiltrating immune cells) and ARDS, potentially affecting immune responses in COVID-19-related ARDS. Concerning in vitro studies, evidence exists of the potential anti-inflammatory activity of DHA on airway epithelial cells and monocytes/macrophages; however, it is necessary to analyze n-3 PUFA immunomodulation using viral experimental models relevant to SARS-CoV-2 infection. Then, although pre-clinical investigations in experimental acute lung injury/ARDS revealed beneficial immunomodulation by n-3 PUFAs when extracellular pathogen infections were used as lung inflammatory models, contradictory results were reported using intracellular viral infections. Finally, clinical trials investigating n-3 PUFA immunomodulation in ARDS are limited, with small samples and contradictory results. In conclusion, further in vitro and in vivo investigations are needed to establish whether n-3 PUFAs may have some therapeutic potential in COVID-19-related ARDS.

n-3 polyunsaturated fatty acids improve depression-like behavior by inhibiting hippocampal neuroinflammation in mice via reducing TLR4 expression

Introduction

n‐3 polyunsaturated fatty acids (PUFAs) are believed to be implicated in the pathogenesis of many inflammation‐related diseases, including depression.

Methods

The mouse model of depression was established through chronic unpredictable mild stress (CUMS), the mice were intervened with n‐3 PUFAs, and then the expression of toll‐like receptor 4 (TLR4) was stimulated with lipopolysaccharides (LPS). Tail suspension test (TST), forced swimming test (FST) and sucrose preference test were performed to monitor the depression behavior of mice. Microglia activation was detected by Iba1 immunofluorescence, and neuronal injury was detected by Nissl staining. Concentrations of tumor necrosis factor (TNF)‐α, Interleukin (IL)‐6 and IL‐1β in the hippocampus were assessed via enzyme linked immunosorbent assay (ELISA). Quantitative real time polymerase chain reaction was used to detect IL‐6, IL‐1β and TNF‐α messenger RNA levels. Western blot was utilized for detection of TLR4 protein expression.

Results

CUMS significantly reduced the sucrose preference in mice, while increased the immobility time in FST and TST. Moreover, CUMS significantly aggravated microglia activation and neuronal damage in mice and increased the levels of IL‐6, IL‐1β and TNF‐α in hippocampal tissues, however, intervention with n‐3 PUFAs could improve the above effects. Further, the increased TLR4 induced by LPS partially reversed the inhibition of n‐3 PUFAs on depression‐like behaviors, microglial activation and inflammatory injury of hippocampal neurons.

Conclusion

n‐3 PUFAs may ameliorate depression‐like behaviors via reducing hippocampal neuroinflammation in CUMS‐induced mice by regulating TLR4 expression, suggesting that n‐3 PUFAs may be an effective antidepressant, which provides evidence for future treatment of depression.

High Endogenously Synthesized N-3 Polyunsaturated Fatty Acids in Fat-1 Mice Attenuate High-Fat Diet-Induced Insulin Resistance by Inhibiting NLRP3 Inflammasome Activation via Akt/GSK-3β/TXNIP Pathway

High-fat (HF) diets and low-grade chronic inflammation contribute to the development of insulin resistance and type 2 diabetes (T2D), whereas n-3 polyunsaturated fatty acids (PUFAs), due to their anti-inflammatory effects, protect against insulin resistance. Interleukin (IL)-1β is implicated in insulin resistance, yet how n-3 PUFAs modulate IL-1β secretion and attenuate HF diet-induced insulin resistance remains elusive. In this study, a HF diet activated NLRP3 inflammasome via inducing reactive oxygen species (ROS) generation and promoted IL-1β production primarily from adipose tissue preadipocytes, but not from adipocytes and induced insulin resistance in wild type (WT) mice. Interestingly, endogenous synthesized n-3 polyunsaturated fatty acids (PUFAs) reversed this process in HF diet-fed fat-1 transgenic mice although the HF diet induced higher weight gain in fat-1 mice, compared with the control diet. Mechanistically, palmitic acid (PA), the main saturated fatty acid in an HF diet inactivated AMPK and led to decreased GSK-3β phosphorylation, at least partially through reducing Akt activity, which ultimately blocked the Nrf2/Trx1 antioxidant pathway and induced TXNIP cytoplasm translocation and NLRP3 inflammasome activation, whereas docosahexaenoic acid (DHA), the most abundant n-3 PUFA in fat-1 adipose tissue, reversed this process via inducing Akt activation. Our GSK-3β shRNA knockdown study further revealed that GSK-3β played a pivot role between the upstream AMPK/Akt pathway and downstream Nrf2/Trx1/TXNIP pathway. Given that NLRP3 inflammasome is implicated in the development of most inflammatory diseases, our results suggest the potential of n-3 PUFAs in the prevention or adjuvant treatment of NLRP3 inflammasome-driven diseases.

Efficacy of the omega-3 fatty acids supplementation on inflammatory biomarkers: An umbrella meta-analysis

BACKGROUND

Existing meta-analyses on omega-3 polyunsaturated fatty acids and their anti-inflammatory effects have reported uncertain findings. The current umbrella meta-analysis aimed to assess the findings of multiple meta-analyses on the efficacy of n-3 PUFAs on inflammatory biomarkers in adults with different health conditions.

METHODS

Using suitable keywords, articles published until December 2021 were searched in PubMed/Medline, Web of Science, Scopus, EMBASE, and Google Scholar. Meta-analyses investigating the impact of supplementation of n-3 PUFAs on inflammatory biomarkers in adults were included. We performed this meta-analysis using a random-effects model.

RESULTS

Overall, 32 meta-analyses were qualified in this umbrella meta-analysis. Our findings demonstrated that the n-3 PUFA supplementation significantly reduced serum C-reactive protein (CRP) (ES = -0.40; 95 % CI: -0.56, -0.24, p < 0.001; I² = 89.5 %, p < 0.001), Tumour necrosis factor α (TNFα) (ES = -0.23; 95 % CI: -0.37, -0.08, p = 0.002; I² = 60.1 %, p < 0.001), and interleukin 6 (IL-6) concentrations (ES = -0.22; 95 % CI: -0.39, -0.05, p = 0.010; I² = 66.2 %, p < 0.001).

CONCLUSION

The current umbrella meta-analysis found that supplementation of n-3 PUFAs in adults can improve CRP, TNF-α, and IL-6 concentrations under various health conditions. n-3 PUFAs can be recommended as adjuvant anti-inflammatory agents.

CRISPR/Cas9-Mediated Transgenesis of the Masu Salmon (Oncorhynchus masou) elovl2 Gene Improves n-3 Fatty Acid Content in Channel Catfish (Ictalurus punctatus)

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), particularly eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), play a very important role in human health. Channel catfish (Ictalurus punctatus) is one of the leading freshwater aquaculture species in the USA, but has low levels of EPA and DHA compared to some fish such as salmon. To improve EPA and DHA content, a modification of the n-3 PUFA biosynthetic pathway was achieved through the insertion of an elovl2 transgene isolated from masu salmon (Oncorhynchus masou) driven by a carp β-actin promoter using a two-hit by gRNA and two oligos with a targeting plasmid (2H2OP) CRISPR/Cas9 approach. Integration rate of the transgene was high (37.5%) and detected in twelve different tissues of P₁ transgenic fish with tissue-specific gene expression. Liver and muscle had relative high gene expression (13.4- and 9.2-fold change, respectively). Fatty acid analysis showed DHA content in the muscle from transgenic fish was 1.62-fold higher than in non-transgenic fish (P < 0.05). Additionally, total n-3 PUFAs and omega-6 polyunsaturated fatty acids (n-6 PUFAs) increased to 1.41-fold and 1.50-fold, respectively, suggesting the β-actin-elovl2 transgene improved biosynthesis of PUFAs in channel catfish as a whole. The n-9 fatty acid level decreased in the transgenic fish compared to the control. Morphometric analysis showed that there were significant differences between injected fish with sgRNAs (including positive and negative fish) and sham-injected controls (P < 0.001). Potential off-target effects are likely the major factor responsible for morphological deformities. Optimization of sgRNA design to maximize activity and reduce off-target effects of CRISPR/Cas9 should be examined in future transgenic research, but this research shows a promising first step in the improvement of n-3 PUFAs in channel catfish.

Effect of Dietary Enrichment with Flaxseed, Vitamin E and Selenium, and of Market Class on the Broiler Breast Meat-Part 1: Nutritional and Functional Traits

The effect of dietary enrichment with flaxseed, selenium and vitamin E, and market class on the nutritional and functional value of breast meat was evaluated. A completely randomized block design was set up, where the experimental unit (n = 6000 birds) received conventional or enriched diet and was slaughtered at 37 (light class), 47 (medium class), or 57 (heavy class) days of life. Hence, functional and standard Pectoralis major muscles from every market class were analyzed for FA composition, inorganic elements and vitamin E. Lipid metabolism indices and health lipid indicators were assessed along with the nutritional value. A multiple linear model revealed that in breasts, the dietary treatment significantly influenced (p < 0.05) the FA profile, lipid metabolism and health lipid indices, while the slaughtering weight was related (p < 0.05) to most of elements (e.g., Na, Mg, K, Mn, and Se) and vitamin E. The interdependence of the two factors had strong relations (p < 0.05) with total PUFAs, including linolenic acid, desaturase activities, health lipid indices, trace essential elements and vitamin E. Consequently, enriched meat from heavy chickens showed the best functional and nutritional traits. Overall, the study pointed out that both market class and dietary manipulation are two relevant factors to consider for producing breast meat with higher nutritional and functional value.

Blood-Brain Barrier Disruption Mediated by FFA1 Receptor-Evidence Using Miniscope

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), obtained from diet and dietary supplements, have been tested in clinical trials for the prevention or treatment of several diseases. n-3 PUFAs exert their effects by activation of free fatty acid (FFA) receptors. FFA1 receptor, expressed in the pancreas and brain, is activated by medium- to long-chain fatty acids. Despite some beneficial effects on cognition, the effects of n-3 PUFAs on the blood-brain barrier (BBB) are not clearly understood. We examined the effects of FFA1 activation on BBB permeability in vitro, using rat brain microvascular endothelial cells (RBMVEC), and in vivo, by assessing Evans Blue extravasation and by performing live imaging of brain microcirculation in adult rats. AMG837, a synthetic FFA1 agonist, produced a dose-dependent decrease in RBMVEC monolayer resistance assessed with Electric Cell-Substrate Impedance Sensing (ECIS); the effect was attenuated by the FFA1 antagonist, GW1100. Immunofluorescence studies revealed that AMG837 produced a disruption in tight and adherens junction proteins. AMG837 increased Evans Blue content in the rat brain in a dose-dependent manner. Live imaging studies of rat brain microcirculation with miniaturized fluorescence microscopy (miniscope) showed that AMG837 increased extravasation of sodium fluorescein. Taken together, our results demonstrate that FFA1 receptor activation reduced RBMVEC barrier function and produced a transient increase in BBB permeability.

Proportions of Polyunsaturated Fatty Acids in Umbilical Cord Blood at Birth Are Related to Atopic Eczema Development in the First Year of Life

Atopic eczema, the most common atopic disease in infants, may pave the way for sensitization and allergy later in childhood. Fatty acids have immune-regulating properties and may regulate skin permeability. Here we examine whether the proportions of fatty acids among the infant and maternal plasma phospholipids at birth were associated with maternal dietary intake during pregnancy and development of atopic eczema during the first year of age in the Nutritional impact on Immunological maturation during Childhood in relation to the Environment (NICE) birth cohort. Dietary data were collected with a semi-quantitative food frequency questionnaire, fatty acids were measured with GC-MS and atopic eczema was diagnosed by a pediatric allergologist at 12 months of age. We found that higher proportions of n-6 PUFAs (including arachidonic acid) but lower proportions of n-3 PUFAs (including DPA) in the infant’s phospholipids at birth were associated with an increased risk of atopic eczema at 12 months of age. The n-6 and n-3 PUFAs were related to maternal intake of meat and fish, respectively. Our results suggest that prenatal exposure to unsaturated fatty acids is associated with eczema development in the infant. Maternal diet during pregnancy may partly explain the fatty acid profiles in utero.

Protective effects on acute hypoxic-ischemic brain damage in mfat-1 transgenic mice by alleviating neuroinflammation

Acute hypoxic-ischemic brain damage (HIBD) mainly occurs in adults as a result of perioperative cardiac arrest and asphyxia. The benefits of n-3 polyunsaturated fatty acids (n-3 PUFAs) in maintaining brain growth and development are well documented. However, possible protective targets and underlying mechanisms of mfat-1 mice on HIBD require further investigation. The mfat-1 transgenic mice exhibited protective effects on HIBD, as indicated by reduced infarct range and improved neurobehavioral defects. RNA-seq analysis showed that multiple pathways and targets were involved in this process, with the anti-inflammatory pathway as the most significant. This study has shown for the first time that mfat-1 has protective effects on HIBD in mice. Activation of a G protein-coupled receptor 120 (GPR120)-related anti-inflammatory pathway may be associated with perioperative and postoperative complications, thus innovating clinical intervention strategy may potentially benefit patients with HIBD.

The Effect of Caloric Restriction with and without n-3 PUFA Supplementation on Bone Turnover Markers in Blood of Subjects with Abdominal Obesity: A Randomized Placebo-Controlled Trial

Weight loss contributes to an increased risk of hip fracture, especially in postmenopausal women. Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation could diminish the adverse effect of weight loss on bone health. The aim of this randomized, placebo-controlled, double-blind parallel trial was to investigate the effect of caloric restriction and n-3 PUFA supplement intake on osteogenic markers (carboxylated osteocalcin (Gla-OC); procollagen I N-terminal propeptide (PINP)), as well as a bone resorption marker (C-terminal telopeptide of type I collagen (CTX-I)) in a serum of 64 middle aged individuals (BMI 25-40 kg/m²) with abdominal obesity. Bone remodeling, metabolic and inflammatory parameters and adipokines were determined before and after 3 months of an isocaloric diet (2300-2400 kcal/day) or a low-calorie diet (1200 kcal/day for women and 1500 kcal/day for men) along with n-3 PUFA (1.8 g/day) or placebo capsules. CTX-I and adiponectin concentrations were increased following 7% weight loss independently of supplement use. Changes in CTX-I were positively associated with changes in adiponectin level (rho = 0.25, p = 0.043). Thus, an increase in serum adiponectin caused by body weight loss could adversely affect bone health. N-3 PUFAs were without effect.

Using Fecal DNA Metabarcoding to Investigate Foraging Reveals the Effects of Specific Herbage on the Improved n-3 Fatty Acid (PUFA) Composition in the Longissimus Dorsi Muscle of Grazing Tan Sheep

Understanding the natural diet of grazing sheep can help fulfill their nutritional requirements and positively affect the quality of their meat. Emerging fecal DNA (fDNA) metabarcoding technology can provide more accurate estimates for the dietary composition of free-ranging animals. This study has shown that pasture feeding can promote deposition of n-3 polyunsaturated fatty acids (PUFAs) in Tan lambs' muscle and decrease the ratio of n-6/n-3 fatty acids (FAs), and thus, we investigated the dietary composition of grazing lambs using fDNA metabarcoding to assess the prevalence of medicinal herbage plants in their diet. Herein, based on the full-time natural pasture grazing and 4-h natural pasture grazing with indoor feeding patterns, the herbage taxa (Bassia scoparia, Euphorbia humifusa, Arnebia euchroma, and Salsola sp.) most correlated to n-3 PUFAs were highlighted to elucidate how diversification in dietary components was associated with the muscle FA profile of lambs. Our findings provide experimental evidence for future feeding research.

Endogenous ω-3 fatty acids in Fat-1 mice attenuated depression-like behaviors, spatial memory impairment and relevant changes induced by olfactory bulbectomy

OBJECTIVES

Olfactory bulbectomy (OB) induced behaviors, hypercortisolism, inflammation and neurotrophin dysfunctions are similar to those observed in depressed patients. Omega (n)-3 polyunsaturated fatty acids (PUFAs) can effectively treat depression via anti-inflammatory and neuroprotective effects. However, n-3 PUFA purities, caloric contents, and ratios in different diets often cause contradictive results. This study used Fat-1 mice, which can convert n-6 to n-3 PUFAs in the brain, to study the effect of n-3 PUFAs on OB-induced behaviors and related changes.

METHODS

Fat-1 and wild-type littermates were fed safflower oil for 3 months. Behaviors were tested on day 21 after surgery. Monoamine neurotransmitters were measured by HPLC. Macrophage activity was measured by MTT assay. Astrocyte phenotypes A1 S100β, A2 BDNF and cholesterol level were measured by ELISA and total cholesterol assay kits respectively. PUFA profile and membrane fluidity were detected by GC and DPH fluorescence probe respectively.

RESULTS

OB significantly induced animal hyperactivity and spatial memory impairment, while decreased sucrose consumption and social contact with decreased 5-HT turnover, increased the macrophage activity and S100β/BDNF ratio. Meanwhile, n-3/n-6 PUFAs ratio and total cholesterol level were reduced in OB mice. Whereas, OB-induced behavioral changes were attenuated, which were associated with increasing 5-HT turnover, decrease macrophage activity, restored S100β/BDNF and n-3/n-6 PUFAs ratios, and total cholesterol concentrations in Fat-1 mice.

CONCLUSION

The present study for the first time demonstrated that endogenous n-3 PUFAs attenuated OB-induced depression-like behaviors and spatial memory impairment through modulating serotonergic and immune function, balancing the astrocyte A1/A2 phenotypes, and normalizing PUFAs profile and membrane function.

Plasma Fatty Acids and Quantitative Ultrasound, DXA and pQCT Derived Parameters in Postmenopausal Spanish Women

Different factors may contribute to the development of osteopenia or osteoporosis. Fatty acids are key nutrients for health, and a number of studies have reported an association between bone mineral density (BMD) and fatty acid intake. We aimed to investigate the relationships between serum levels of different fatty acids and bone parameters determined by quantitative bone ultrasound (QUS), peripheral quantitative computed tomography (pQCT), and dual-energy X-ray absorptiometry (DXA) in a sample of Spanish postmenopausal women. We enrolled a total of 301 postmenopausal women (median age 59 years; interquartile range (IQR) 7) in this study. All participants underwent full densitometric screening, including calcaneal quantitative ultrasound (QUS), peripheral quantitative computed tomography (pQCT), and dual-energy X-ray absorptiometry (DXA), as well as plasma fatty acid measurement. After adjustment for potential confounders, plasma n-3 polyunsaturated fatty acid (PUFA) levels correlated with BMD in the spine (r = 0.150; p = 0.014) and femoral neck (r = 0.143; p = 0.019). By multiple linear regression, an independent statistically significant positive relationship was observed between BMD in the spine and BMI (β = 0.288; p = 0.001) as well as total plasma n-3 PUFAs (β = 0.155; p = 0.009). The plasma n-3 PUFA level was also a significant and positive predictor of BMD at the femoral neck (β = 0.146; p = 0.009). Independent risk factors for low BMD (T-score ≤ 1) were determined by logistic regression analysis, and a relatively high level of plasma n-3 PUFAs (OR = 0.751; 95% CI 0.587-0.960, p = 0.022) was identified as a protective factor against low bone mass. In this single-center sample of Spanish postmenopausal women, we reported a significant positive and statistically independent association between BMD and plasma levels of n-3 PUFAs.

Perinatal Dietary Polyunsaturated Fatty Acids in Brain Development, Role in Neurodevelopmental Disorders

n-3 and n-6 polyunsaturated fatty acids (PUFAs) are essential fatty acids that are provided by dietary intake. Growing evidence suggests that n-3 and n-6 PUFAs are paramount for brain functions. They constitute crucial elements of cellular membranes, especially in the brain. They are the precursors of several metabolites with different effects on inflammation and neuron outgrowth. Overall, long-chain PUFAs accumulate in the offspring brain during the embryonic and post-natal periods. In this review, we discuss how they accumulate in the developing brain, considering the maternal dietary supply, the polymorphisms of genes involved in their metabolism, and the differences linked to gender. We also report the mechanisms linking their bioavailability in the developing brain, their transfer from the mother to the embryo through the placenta, and their role in brain development. In addition, data on the potential role of altered bioavailability of long-chain n-3 PUFAs in the etiologies of neurodevelopmental diseases, such as autism, attention deficit and hyperactivity disorder, and schizophrenia, are reviewed.

Omega-3 Polyunsaturated Fatty Acids: Versatile Roles in Blood Pressure Regulation

Significance: Hypertension is characterized as the imbalance of vasoconstriction and vasodilatation. Hypertension is influenced by genetic variation and environmental risk factors, such as unhealthy diet. Clinical trial results suggest that increasing intake of foods rich in n-3 polyunsaturated fatty acids (PUFAs) is beneficial for hypertension. Recent Advances: We summarized recent clinical trials regarding supplementation with n-3 PUFAs to reduce blood pressure (BP) in untreated hypertensive and normotensive subjects and systematically discussed the antihypertension mechanisms of n-3 PUFAs/n-3 oxylipins, including reducing oxidative stress, altering functions of membrane-related proteins, and competing with n-6 PUFAs/n-6 oxylipins in regulating vasodilator release. Critical Issues: Previous studies considered n-3 PUFAs as single molecules with beneficial roles in hypertension. Recently, researchers have paid more attention to the metabolism of n-3 PUFAs and explored molecular mechanisms of n-3 PUFAs and oxylipins derived from n-3 PUFAs in hypertension interventions. Future Directions: Based on the metabolism of n-3 PUFAs/n-3 oxylipins and mechanisms in BP control, we suggested that supplementation of n-3 PUFAs combined with agents targeting PUFA metabolism or the related signal pathways may amplify their effects to treat hypertension and other cardiovascular diseases. Antioxid. Redox Signal. 34, 800-810.

Effects of n-3 EPA and DHA supplementation on fat free mass and physical performance in elderly. A systematic review and meta-analysis of randomized clinical trial

The most studied n-3 polyunsaturated fatty acids (n-3 PUFAs) are eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), and their intake seem to have a positive effect on skeletal muscle. This systematic review and meta-analysis aims to investigate the effect of n-3 EPA and DHA supplementation on fat free mass, and on different indexes of physical performance in the elderly. Eligible studies included RCT studies that investigated EPA and DHA intervention. Random-effects models have been used in order to estimate pooled effect sizes, the mean differences, and 95 % CIs. Findings from 14 studies (n = 2220 participants) lasting from 6 to 144 weeks have been summarized in this article. The meta-analyzed mean differences for random effects showed that daily n-3 EPA + DHA supplementation (from 0.7 g to 3.36 g) decreases the time of Time Up and Go (TUG) test of -0.28 s (CI 95 %-0.43, -0.13;). No statistically significant effects on physical performance indicators, such as 4-meter Walking Test, Chair Rise Test and Handgrip Strength, have been found. The fat free mass follows an improvement trend of +0.30 kg (CI 95 % -0.39, 0.99) but not statistically significant. N-3 EPA + DHA supplementation could be a promising strategy in order to enhance muscle quality and prevent or treat frailty.

Endogenous conversion of n-6 to n-3 polyunsaturated fatty acids facilitates the repair of cardiotoxin-induced skeletal muscle injury in fat-1 mice

In this study, we investigated the beneficial effects of high endogenous levels of n-3 polyunsaturated fatty acids (PUFAs) on skeletal muscle repair and regeneration using a mouse cardiotoxin (CTX, 20 μM/200 μL) -induced gastrocnemius muscle injury model. Transgenic fat-1 mice expressing the Caenorhabditis elegans fat-1 gene, encoding n-3 fatty acid desaturase, showed higher n-3 PUFA levels and lower n-6/n-3 PUFA ratios in gastrocnemius muscle tissues. Hematoxylin and eosin and Masson’s trichrome staining of gastrocnemius sections revealed increased muscle fiber size and reduced fibrosis in fat-1 mice on days 7 and 14 after CTX injections. Gastrocnemius muscle tissues from fat-1 mice showed reduced inflammatory responses and increased muscle fiber regeneration reflecting enhanced activation of satellite cells on day 3 after cardiotoxin injections. Gastrocnemius muscle tissues from cardiotoxin-treated fat-1 mice showed reduced levels of pro-apoptotic proteins (Caspase 3 and Bax) and increased levels of anti-apoptotic proteins (Bcl-2 and Survivin). Moreover, eicosapentaenoic acid (EPA) reduced the incidence of apoptosis among cardiotoxin-treated C2C12 mouse myoblasts. These findings demonstrate that higher endogenous n-3 PUFA levels in fat-1 mice enhances skeletal muscle repair and regeneration following cardiotoxin-induced injury.

Inflammatory Depression-Mechanisms and Non-Pharmacological Interventions

Treatment of depression is hampered by the failure to identify distinct symptom profiles with distinct pathophysiologies that differentially respond to distinct treatments. We posit that inflammatory depression is a meaningful depression subtype associated with specific symptoms and biological abnormalities. We review several upstream, potentially causative, mechanisms driving low-grade inflammation in this subtype of depression. We also discuss downstream mechanisms mediating the link between inflammation and symptoms of depression, including alterations in dopaminergic neurotransmission and tryptophan metabolism. Finally, we review evidence for several non-pharmacological interventions for inflammatory depression, including probiotics, omega-3 fatty acids, and physical exercise interventions. While some evidence suggests that these interventions may be efficacious in inflammatory depression, future clinical trials should consider enriching patient populations for inflammatory markers, or stratify patients by inflammatory status, to confirm or refute this hypothesis.

Effects of Omega-3 Fatty Acids on Muscle Mass, Muscle Strength and Muscle Performance among the Elderly: A Meta-Analysis

There is increasing evidence showing the role of fatty acids and their derived lipid intermediates in the regulation of skeletal muscle mass synthesis and function. However, the role of omega-3 fatty acids remains unclear. Therefore, we conducted a meta-analysis to evaluate the potential effects of omega-3 fatty acids on sarcopenia-related performances among the elderly. Eligible literature and reports of randomized controlled trials were comprehensively searched from the PubMed, Cochrane Library, ClinicalTrials.gov, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases until July 2018. A total of 10 articles were available for the meta-analysis. There were minor benefits for muscle mass gain (0.33 kg; 95% CI: 0.05, 0.62) and timed up and go performance (−0.30 s; 95% CI: −0.43, −0.17). Subgroup analyses regarding muscle mass and walk speed indicated that omega-3 fatty acid supplements at more than 2 g/day may contribute to muscle mass gain (0.67 kg; 95% CI: 0.16, 1.18) and improve walking speed, especially for those receiving more than 6 months of intervention (1.78 m/sec; 95% CI: 1.38, 2.17). Our findings provide some insight into the effects of omega-3 fatty acids on muscle mass, especially for those taking supplements at more than 2 g/day. We also observed that a long period of omega-3 fatty acids supplementation may improve walking speed.

Potential use of n-3 PUFAs to prevent oxidative stress-derived ototoxicity caused by platinum-based chemotherapy

Platinum-based compounds are widely used for the treatment of different malignancies due to their high effectiveness. Unfortunately, platinum-based treatment may lead to ototoxicity, an often-irreversible side effect without a known effective treatment and prevention plan. Platinum-based compound-related ototoxicity results mainly from the production of toxic levels of reactive oxygen species (ROS) rather than DNA-adduct formation, which has led to test strategies based on direct ROS scavengers to ameliorate hearing loss. However, favorable clinical results have been associated with several complications, including potential interactions with chemotherapy efficacy. To understand the contribution of the different cytotoxic mechanisms of platinum analogues on malignant cells and auditory cells, the particular susceptibility and response of both kinds of cells to molecules that potentially interfere with these mechanisms, is fundamental to develop innovative strategies to prevent ototoxicity without affecting antineoplastic effects. The n-3 long-chain polyunsaturated fatty acids (n-3 PUFAs) have been tried in different clinical settings, including with cancer patients. Nevertheless, their use to decrease cisplatin-induced ototoxicity has not been explored to date. In this hypothesis paper, we address the mechanisms of platinum compounds-derived ototoxicity, focusing on the differences between the effects of these compounds in neoplastic versus auditory cells. We discuss the basis for a strategic use of n-3 PUFAs to potentially protect auditory cells from platinum-derived injury without affecting neoplastic cells and chemotherapy efficacy.

Effects of Edible Oils with Different n-6/n-3 PUFA Ratios on Articular Cartilage Degeneration via Regulating the NF-κB Signaling Pathway

Osteoarthritis (OA), a common chronic disease, is characterized by articular cartilage degeneration and inflammation. Recent studies report that n-3 polyunsaturated fatty acids (PUFAs) exhibit protective effects against OA, while n-6 PUFAs are more likely to damage cartilage. However, the effects of edible oils with different n-6/n-3 PUFA ratios on OA are rarely reported. This study investigates the effect of linseed oil (LO), soybean oil (SO), and peanut oil (PO) on cartilage changes in mice joints following destabilization of the medial meniscus. We determined the n-6/n-3 PUFA ratios of LO, SO, and PO used in this experiment to be 1:3.85, 9.15:1, and 372.73:1, respectively. After 12 weeks of LO or SO feeding, OA mice showed increased cartilage thickness and decreased TNF-α in both the serum and cartilage, whereas no improvement was found in the PO group. This may be due to the fact that LO and SO optimized the fatty acid composition of articular cartilage. We further demonstrated that LO or SO activated GPR120 and attenuated EP4, which was followed by inhibition of the NFκB pathway and its downstream matrix-degrading enzymes: MMP13 and ADAMTS5. In conclusion, edible oils with low n-6/n-3 PUFA retard OA progression via inhibiting the NFκB pathway. This study provides a dietary guidance for OA patients.

The Anti-Inflammatory and Antioxidant Properties of n-3 PUFAs: Their Role in Cardiovascular Protection

Polyunsaturated fatty acids (n-3 PUFAs) are long-chain polyunsaturated fatty acids with 18, 20 or 22 carbon atoms, which have been found able to counteract cardiovascular diseases. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in particular, have been found to produce both vaso- and cardio-protective response via modulation of membrane phospholipids thereby improving cardiac mitochondrial functions and energy production. However, antioxidant properties of n-3 PUFAs, along with their anti-inflammatory effect in both blood vessels and cardiac cells, seem to exert beneficial effects in cardiovascular impairment. In fact, dietary supplementation with n-3 PUFAs has been demonstrated to reduce oxidative stress-related mitochondrial dysfunction and endothelial cell apoptosis, an effect occurring via an increased activity of endogenous antioxidant enzymes. On the other hand, n-3 PUFAs have been shown to counteract the release of pro-inflammatory cytokines in both vascular tissues and in the myocardium, thereby restoring vascular reactivity and myocardial performance. Here we summarize the molecular mechanisms underlying the anti-oxidant and anti-inflammatory effect of n-3 PUFAs in vascular and cardiac tissues and their implication in the prevention and treatment of cardiovascular disease.

Concurrent EPA and DHA Supplementation Impairs Brown Adipogenesis of C2C12 Cells

Maternal dietary supplementation of n−3 polyunsaturated fatty acids (n−3 PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is considered to play positive roles in fetal neuro system development. However, maternal n−3 PUFAs may induce molecular reprogramming of uncommitted fetal myoblasts into adipocyte phenotype, in turn affecting lipid metabolism and energy expenditure of the offspring. The objective of this in vitro study was to investigate the combined effects of EPA and DHA on C2C12 cells undergoing brown adipogenic differentiation. C2C12 myoblasts were cultured to confluency and then treated with brown adipogenic differentiation medium with and without 50 μM EPA and 50 μM DHA. After differentiation, mRNA and protein samples were collected. Gene expression and protein levels were analyzed by real-time PCR and western blot. General Proteomics analysis was conducted using mass spectrometric evaluation. The effect of EPA and DHA on cellular oxygen consumption was measured using a Seahorse XFP Analyzer. Cells treated with n−3 PUFAs had significantly less (P < 0.05) expression of the brown adipocyte marker genes PGC1α, DIO2, and UCP3. Expression of mitochondrial biogenesis-related genes TFAM, PGC1α, and PGC1β were significantly downregulated (P < 0.05) by n−3 PUFAs treatment. Expression of mitochondrial electron transportation chain (ETC)-regulated genes were significantly inhibited (P < 0.05) by n−3 PUFAs, including ATP5J2, COX7a1, and COX8b. Mass spectrometric and western blot evaluation showed protein levels of enzymes which regulate the ETC and Krebs cycle, including ATP synthase α and β (F1F0 complex), citrate synthase, succinate CO-A ligase, succinate dehydrogenase (complex II), ubiquinol-cytochrome c reductase complex subunits (complex III), aconitate hydratase, cytochrome c, and pyruvate carboxylase were all decreased in the n−3 PUFAs group (P < 0.05). Genomic and proteomic changes were accompanied by mitochondrial dysfunction, represented by significantly reduced oxygen consumption rate, ATP production, and proton leak (P < 0.05). This study suggested that EPA and DHA may alter the BAT fate of myoblasts by inhibiting mitochondrial biogenesis and activity and induce white-like adipogenesis, shifting the metabolism from lipid oxidation to synthesis.

The Link between Homocysteine and Omega-3 Polyunsaturated Fatty Acid: Critical Appraisal and Future Directions

Omega-3 polyunsaturated fatty acids and B vitamins are linked to metabolic and degenerative disorders, such as cardiovascular disease and cognitive decline. In the last two decades, the interplay between B vitamins and omega-3 polyunsaturated fatty acids gained increasing attention. Expression control on enzymes involved in the pathway of homocysteine by polyunsaturated fatty acids has been proposed. The methylation process seems crucial for the metabolism of polyunsaturated fatty acids and their distribution within the body. This review summarizes the available data in humans about the link between homocysteine and omega-3 polyunsaturated fatty acids, with a special focus on the meta-analyses of randomized clinical trials. Even if the paucity of available information about the topic does not allow for definitive conclusions, a synergic action between polyunsaturated fatty acids and B vitamins may play a key role in regulating several metabolic pathways. This element could explain a stronger action on homocysteine levels when omega-3 polyunsaturated fatty acids and B vitamins are supplemented simultaneously. To date, a robust rationale of intervention to prevent metabolic diseases is lacking and could be beneficial for individual health and healthcare policy.

Omega-3 fatty acids as regulators of brown/beige adipose tissue: from mechanisms to therapeutic potential

Adipose tissue dysfunction represents the hallmark of obesity. Brown/beige adipose tissues play a crucial role in maintaining energy homeostasis through non-shivering thermogenesis. Brown adipose tissue (BAT) activity has been inversely related to body fatness, suggesting that BAT activation is protective against obesity. BAT plays also a key role in the control of triglyceride clearance, glucose homeostasis, and insulin sensitivity. Therefore, BAT/beige activation has been proposed as a strategy to prevent or ameliorate obesity development and associated commorbidities. In the last few years, a variety of preclinical studies have proposed n-3 polyunsaturated fatty acids (n-3 PUFAs) as novel inducers of BAT activity and white adipose tissue browning. Here, we review the in vitro and in vivo available evidences of the thermogenic properties of n-3 PUFAs, especially focusing on the molecular and cellular physiological mechanisms involved. Finally, we also discuss the challenges and future perspectives to better characterize the therapeutic potential of n-3 PUFAs as browning agents, especially in humans.

Variation in Lipid Components from 15 Species of Tropical and Temperate Seaweeds

The present study describes the variation in lipid components from 15 species of seaweeds belonging to the Chlorophyta, Ochrophyta, and Rhodophyta phyla collected in tropical (Indonesia) and temperate (Japan) areas. Analyses were performed of multiple components, including chlorophylls, carotenoids, n-3 and n-6 polyunsaturated fatty acids (PUFAs), and alpha tocopherol (α-Toc). Chlorophyll (Chl) and carotenoid contents varied among phyla, but not with the sampling location. Chl a and b were the major chlorophylls in Chlorophyta. Chl a and Chl c were the main chlorophylls in Ochrophyta, while Chl a was the dominant chlorophylls in Rhodophyta. β-Carotene and fucoxanthin were detected as major seaweed carotenoids. The former was present in all species in a variety of ranges, while the latter was mainly found in Ochrophyta and in small quantities in Rhodophyta, but not in Chlorophyta. The total lipids (TL) content and fatty acids composition were strongly affected by sampling location. The TL and n-3 PUFAs levels tended to be higher in temperate seaweeds compared with those in tropical seaweeds. The major n-3 PUFAs in different phyla, namely, eicosapentaenoic acid (EPA) and stearidonic acid (SDA) in Ochrophyta, α-linolenic acid (ALA) and SDA in Chlorophyta, and EPA in Rhodophyta, accumulated in temperate seaweeds. Chlorophylls, their derivatives, and carotenoids are known to have health benefits, such as antioxidant activities, while n-3 PUFAs are known to be essential nutrients that positively influence human nutrition and health. Therefore, seaweed lipids could be used as a source of ingredients with health benefits for functional foods and nutraceuticals.

Effects of eicosapentaenoic acid and docosahexaenoic acid on C2C12 cell adipogenesis and inhibition of myotube formation

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) modulate cellular metabolic functions and gene expression. This study investigated the impacts of EPA and DHA on gene expression and morphological changes during adipogenic inducement in C2C12 myoblasts. Cells were cultured and treated with differentiation medium with and without 50 μM EPA and DHA. Cells treated with fatty acids had noticeable lipid droplets, but no formation of myotubes compared to control group cells. The expression levels of key genes relevant to adipogenesis and inflammation were significantly higher (P < 0.05) in cells treated with fatty acids. Genes associated with myogenesis and mitochondrial biosynthesis and function had lower (P < 0.05) expression with fatty acids supplementation. Moreover, fatty acid treatment reduced (P < 0.05) oxygen consumption rate in the differentiated cells. This suggested blocking myotube formation through supplementation with EPA and DHA drove myoblasts to enter the quiescent state and enabled adipogenic trans-differentiation of the myoblasts. Data also suggested that overdosage of EPA and DHA during gestation may drive fetal mesenchymal stem cell differentiation to the fate of adipogenesis and have a long-term effect on childhood obesity.

The Physiological Effect of n-3 Polyunsaturated Fatty Acids (n-3 PUFAs) Intake and Exercise on Hemorheology, Microvascular Function, and Physical Performance in Health and Cardiovascular Diseases; Is There an Interaction of Exercise and Dietary n-3 PUFA Intake?

Physical activity has a beneficial effect on systemic hemodynamics, physical strength, and cardiac function in cardiovascular (CV) patients. Potential beneficial effects of dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs), such as α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid on hemorheology, vascular function, inflammation and potential to improve physical performance as well as other CV parameters are currently investigated. Recent meta-analysis suggests no effect of n-3 PUFA supplementation on CV function and outcomes of CV diseases. On the other hand, some studies support beneficial effects of n-3 PUFAs dietary intake on CV and muscular system, as well as on immune responses in healthy and in CV patients. Furthermore, the interaction of exercise and dietary n-3 PUFA intake is understudied. Supplementation of n-3 PUFAs has been shown to have antithrombotic effects (by decreasing blood viscosity, decreasing coagulation factor and PAI-1 levels and platelet aggregation/reactivity, enhancing fibrinolysis, but without effects on erythrocyte deformability). They decrease inflammation by decreasing IL-6, MCP-1, TNFα and hsCRP levels, expression of endothelial cell adhesion molecules and significantly affect blood composition of fatty acids. Treatment with n-3 PUFAs enhances brachial artery blood flow and conductance during exercise and enhances microvascular post-occlusive hyperemic response in healthy humans, however, the effects are unknown in cardiovascular patients. Supplementation of n-3 PUFAs may improve anaerobic endurance and may modulate oxygen consumption during intense exercise, may increase metabolic capacity, enhance endurance capacity delaying the onset of fatigue, and improving muscle hypertrophy and neuromuscular function in humans and animal models. In addition, n-3 PUFAs have anti-inflammatory and anti-nociceptive effects and may attenuate delayed-onset muscle soreness and muscle stiffness, and preserve joint mobility. On the other hand, effects of n-3 PUFAs were variably observed in men and women and they vary depending on dietary protocol, type of supplementation and type of sports activity undertaken, both in healthy and cardiovascular patients. In this review we will discuss the physiological effects of n-3 PUFA intake and exercise on hemorheology, microvascular function, immunomodulation and inflammation and physical performance in healthy persons and in cardiovascular diseases; elucidating if there is an interaction of exercise and diet.

Anti-pain and anti-inflammation like effects of Neptune krill oil and fish oil against carrageenan induced inflammation in mice models: Current statues and pilot study

Although inflammation is a reactive to injurious stimuli and considered as beneficial process in body, but it causes some discomforts, such as pain. Murine dietary contains appreciable amounts of fatty acids and antioxidants which encourages researchers to focus on their potential therapeutic effects. This study is aimed to examine the analgesic and anti-inflammatory activity of Neptune krill oil (NKO) and fish oil (FO) in rodent model which are two well-known sources of rich content of n-3 polyunsaturated fatty acids (n-3 PUFAs), mostly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). NKO and FO were used at the same dose of 500 mg and also balanced at similar doses of EPA: 12 in NKO vs. 12 in FO wt%, DHA: 7 NKO vs. 8 FO wt%. Application of NKO and FO in acetic acid-induced writhing effect, hot plate, and formalin induced test, indicated the nociceptive activity of the two tested drugs in comparison with normal saline. Also, the anti-inflammatory effect of these supplements was confirmed by carrageenan test. Analysis of cytokines levels in the blood samples of the mice after induction inflammation by carrageenan indicated decreased levels of those proteins compared to that in the normal groups. Both tested drugs, effectively could reduce severe inflammation and pain in rodents in comparison with the references drugs (depends on the tests); however, NKO was found to be more effective.

The emerging role of omega-3 fatty acids as a therapeutic option in neuropsychiatric disorders

The prevalence of neurologic and psychiatric diseases has been increasing for decades and, given the moderate therapeutic efficacy and safety profile of existing pharmacological treatments, there is an urgent need for new therapeutic approaches. Nutrition has recently been recognized as an important factor for the prevention and treatment of neuropsychiatric disorders. The omega-3 polyunsaturated fatty acids (n-3 PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play critical roles in neuronal cell function and neurotransmission as well as inflammatory and immune reactions that are involved in neuropsychiatric disease states. A large number of experimental and epidemiological studies provide a strong basis for interventional clinical trials that assessed the clinical efficacy of n-3 PUFAs in various neurological and psychiatric disorders. Most of these trials found beneficial effects of dietary supplementation with EPA and DHA, and no serious safety concerns have emerged. This review gives an introduction to recent findings on the clinical efficacy of n-3 PUFAs in various neuropsychiatric disorders and the underlying biochemical mechanisms. In addition, the reader will be enabled to identify common methodological weaknesses of clinical studies on n-3 PUFAs, and suggestions for the design of future studies are given.

Fish oil supplement use in New Zealand: A cross-sectional survey

OBJECTIVE

The aims of the survey were to determine: (i) the percentage of fish oil supplement users in a sample population; (ii) why people take fish oil supplements; (iii) where fish oil supplements are stored as well as the average daily dosage; (iv) what dietary and lifestyle behaviours are associated with fish oil supplement use.

DESIGN

An online cross-sectional survey.

SETTING

New Zealand.

RESPONDENTS

A total of 334 New Zealand residents over the age of 18.

RESULTS

Fish oil supplements were taken by 21.9% of respondents. Reasons for taking fish oil supplements were - 72.6% for 'general well-being', 54.8% to 'improve brain function', 31.5% for 'pain/inflammation', 12.3% to 'lower cholesterol levels' and 11% for 'a dietary insufficiency'. Approximately 26% of fish oil users reported taking a dose of fish oil supplements that would meet the recommended daily intake of 400-600 mg combined docosahexaenoic acid and eicosapentaenoic acid, and only 6.8% of fish oil users reported storing their fish oil supplements in the refrigerator. After controlling for other characteristics including age, gender, ethnicity and body mass index, fish oil supplementation use was most likely among respondents who already eat oily fish and least likely in respondents who regularly eat nuts and seeds.

CONCLUSIONS

Fish oil supplements are a commonly used supplement in New Zealand, yet questions remain about the role of these supplements in improving health outcomes. Safety issues related to manufacturing and storage conditions indicate that there is an urgency in answering these questions.

Volatile compounds and sensory profile of burgers with 50% fat replacement by microparticles of chia oil enriched with rosemary

Direct incorporation of rosemary leaves into chia oil (CO) was performed by ultrasound-assisted extraction (UAE) and conventional maceration extraction (CME). CO was microencapsulated and used in burgers, as follows: control (20% pork back fat (PBF)); HCO (10% PBF + 7.5% water +2.5% unencapsulated CO); HM1 (10% PBF + 10% CO microparticles); HM2 (10% PBF + 10% CO microparticles enriched by UAE) and HM3 (10% PBF + 10% CO microparticles enriched by CME). The volatile compounds and the sensory properties (Check-All-That-Apply and overall acceptability) of burgers were evaluated at days 1 and 120 of frozen storage. The control, HCO, and HM1 groups were characterized for volatile compounds produced by lipid and protein oxidation, and sensory descriptors related to lipid oxidation. HM2 and HM3 groups presented an increase in terpenic volatiles and were characterized by the descriptors herbal and pleasant aroma and ideal texture. In addition, liking scores were positively correlated to the descriptors that characterized the HM2 and HM3 groups.

The effect of n-3 PUFAs on circulating adiponectin and leptin in patients with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

AIM

N-3 PUFAs can potentially influence levels of inflammatory and non-inflammatory adipokines. Given the contradictory effects of n-3 PUFAs on serum levels of adipokines in type 2 diabetes, we conducted a systematic review and meta-analysis study of randomized placebo-controlled clinical trials that examined the effects of n-3 PUFAs on serum levels of leptin and adiponectin in patients with type 2 diabetes.

METHODS

The electronic databases, without regard to language restrictions including PubMed/Medline, Google Scholar, SCOPUS and ISI Web of Science until August 2017, were used to identify randomized controlled trials that assessed the effect of n-3 PUFAs on serum leptin and adiponectin concentrations in type 2 diabetes. Outcomes were extracted based on the mean ± SD as effect size at baseline and end of the intervention. Between-study heterogeneity was evaluated by the I² estimates and their 95% CIs. Funnel plot asymmetry was used to investigate the existence of publication bias. Stata software and Review Manager were used for statistical data analysis.

RESULTS

Data from 10 eligible articles involved 494 subjects with type 2 diabetes mellitus (intervention groups = 254 and control groups = 240), with age between 44 and 70 years, treated with doses of 0.52-7.4 g/day n-3 PUFAs. Adiponectin concentration nonsignificantly increased by a MD = 0.17 µg/mL (95% CI - 0.11, 0.44). Also, leptin concentration nonsignificantly reduced by a MD = - 0.31 ng/mL (95% CI - 0.69, 0.07).

CONCLUSION

Plant and marine sources of n-3 PUFAs can modify serum leptin and adiponectin levels by increasing adiponectin and decreasing leptin levels in patients with type 2 diabetes. Due to some limitations in this study, further studies are needed to reach a definitive conclusion about the effect of n-3 PUFAs on the levels of leptin and adiponectin in T2DM.

Implications of PI3K/AKT/PTEN Signaling on Superoxide Dismutases Expression and in the Pathogenesis of Alzheimer's Disease

Alzheimer’s disease is a neurodegenerative sickness, where the speed of personal disease progression differs prominently due to genetic and environmental factors such as life style. Alzheimer’s disease is described by the construction of neuronal plaques and neurofibrillary tangles composed of phosphorylated tau protein. Mitochondrial dysfunction may be a noticeable feature of Alzheimer’s disease and increased production of reactive oxygen species has long been described. Superoxide dismutases (SODs) protect from excess reactive oxygen species to form less reactive hydrogen peroxide. It is suggested that SODs can play a protective role in neurodegeneration. In addition, PI3K/AKT pathway has been shown to play a critical role on the neuroprotection and inhibiting apoptosis via the enhancing expression of the SODs. This pathway appears to be crucial in Alzheimer’s disease because it is related to the tau protein hyper-phosphorylation. Dietary supplementation of several ordinary compounds may provide a novel therapeutic approach to brain disorders by modulating the function of the PI3K/AKT pathway. Understanding these systems may offer a better efficacy of new therapeutic approaches. In this review, we summarize recent progresses on the involvement of the SODs and PI3K/AKT pathway in neuroprotective signaling against Alzheimer’s disease.

The role of polyunsaturated fatty acids (n-3 PUFAs) on the pancreatic β-cells and insulin action

Polyunsaturated Fatty acids have multiple effects in peripheral tissues and pancreatic beta cell function. The n-3 Polyunsaturated Fatty acids prevent and reverse high-fat-diet induced adipose tissue inflammation and insulin resistance. Insulin secretion is stimulated by glucose, amino acids, and glucagon- like peptide-1 in tissue containing high levels of n-3 Polyunsaturated Fatty acids than lower level of n-3 Polyunsaturated Fatty acids. Also, n-3 Polyunsaturated Fatty acids led to decreased production of prostaglandin, which in turn contributed to the elevation of insulin secretion. N-3 polyunsaturated fatty acids prevent cytokine-induced cell death in pancreatic islets. Supplementation of n-3 Polyunsaturated Fatty acids for human subjects prevent beta cell destruction and insulin resistance. It also enhances insulin secretion, reduction in lipid profiles and glucose concentration particularly in type II diabetes patients. Therefore there should be a focus on the treatment mechanism of insulin related obesity and diabetes by n-3 polyunsaturated fatty acids.

Omega-3 Polyunsaturated Fatty Acids Time-Dependently Reduce Cell Viability and Oncogenic MicroRNA-21 Expression in Estrogen Receptor-Positive Breast Cancer Cells (MCF-7)

The omega-3 polyunsaturated fatty acid (n-3 PUFA), α-linolenic acid (ALA), and its metabolites, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), independently reduce the growth of breast cancer cells in vitro, but the mechanisms, which may involve microRNA (miRNA), are still unclear. The expression of the oncomiR, miR-21, is reduced by DHA treatment, but the effects of ALA on miR-21, alone or combined with EPA and DHA under physiologically relevant concentrations, have not been investigated. The effects of ALA alone and +/-EPA and DHA at the blood molar ratios seen in either humans (1.0:1.0:2.5, ALA:EPA:DHA) or mice (1.0:0.4:3.1, ALA:EPA:DHA) post flaxseed oil consumption (containing ALA) were assessed in vitro in MCF-7 breast cancer cells. Cell viability and the expression of miR-21 and its molecular target, phosphatase and tension homolog (PTEN, gene and protein), at different time points, were examined. At 1, 3, 48 and 96 h ALA alone and 24 h animal ratio treatments significantly reduced MCF-7 cell viability, while 1 and 3 h ALA alone and human and animal ratio treatments all significantly reduced miR-21 expression, and 24 h animal ratio treatment reduced miR-21 expression; these effects were not associated with changes in PTEN gene or protein expressions. We showed for the first time that ALA alone or combined with EPA and DHA at levels seen in human and animal blood post-ALA consumption can significantly reduce cell viability and modulate miR-21 expression in a time- and concentration-dependent manner, with the animal ratio containing higher DHA having a greater effect. The time dependency of miR-21 effects suggests the significance of considering time as a variable in miRNA studies, particularly of miR-21.