N-3 Polyunsaturated Fatty Acids Ameliorate Neurobehavioral Outcomes Post-Mild Traumatic Brain Injury in the Fat-1 Mouse Model.

Concussions and mild traumatic brain injury (m-TBI) have been identified as a consequential public health concern because of their potential to cause considerable impairments in physical, cognitive, behavioral, and social functions. Given their prominent structural and functional roles in the brain, n-3 polyunsaturated fatty acids (PUFA) have been identified as a potentially viable prophylactic agent that may ameliorate the deleterious effects of m-TBI on brain function. The purpose of the present pilot study was to investigate the effect of n-3 PUFA on neurologic function using a weight drop injury (WDI) model. Fat-1 mice, capable of synthesizing n-3 PUFA endogenously from n-6 PUFA, and their wild-type (WT) counterparts, were subjected to a mild low-impact WDI on the closed cranium, and recovery was evaluated using the neurological severity score (NSS) to assess the motor and neurobehavioral outcomes. In comparison to the WT mice, the fat-1 mice had a significantly (p ≤ 0.05) lower NSS at all time points post-WDI, and significantly greater neurological restoration measured as the time to first movement. Overall, these findings demonstrate the protective effect of n-3 PUFA against mild brain injury.

Dietary ω-3 polyunsaturated fatty acids modulate CD4+ T-cell subset markers, adipocyte antigen-presentation potential, and NLRP3 inflammasome activity in a coculture model of obese adipose tissue.

OBJECTIVES: Chronic low-grade inflammation in obesity is partly driven by inflammatory cross talk between adipocytes and interferon-γ-secreting CD4+ T-helper (Th)1 cells, a process we have shown may be mitigated by long-chain (LC) ω-3 polyunsaturated fatty acids (PUFAs). Our objective was to study pivotal mediators of interactions between Th1 cells and adipocytes as potential mechanisms underlying the antiinflammatory effects of LC ω-3 PUFAs. METHODS: Using an in vitro model, 3T3-L1 adipocytes were cocultured with purified splenic CD4+ T cells from C57BL/6 mice consuming one of two isocaloric high-fat (HF) diets (60% kcal fat), containing either 41.2% kcal from lard + 18.7% kcal from corn oil (control, HF) or 41.2% kcal from lard + 13.4% kcal from corn oil + 5.3% kcal from fish oil (HF+FO). Cocultures were stimulated for 48 h with lipopolysaccharide (10 ng/mL). RESULTS: Compared with HF cocultures, HF+FO reduced Th1-cell markers (including secreted interferon-γ) and increased Th2-cell markers, consistent with reduced expression of genes related to major histocompatibility complex II (P < 0.05). HF+FO also blunted markers of priming and activity of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome (P < 0.05). In confirmatory work, 3T3-L1 adipocyte pretreatment with the LC ω-3 PUFA docosahexaenoic acid (100 µM, 24 h) blunted interferon-γ-induced (5 ng/mL, 24 h) expression of genes related to major histocompatibility complex II and priming and activity markers of the NLRP3 inflammasome compared with control (P < 0.05). CONCLUSIONS: Inflammatory interactions between CD4+ T cells and adipocytes may provide a target for LC ω-3 PUFAs to mitigate obesity-associated inflammation.

Fish oil supplementation increases expression of mammary tumor apoptosis mediators and reduces inflammation in an obesity-associated HER-2 breast cancer model.

Obesity is associated with inflammation and has been shown to increase breast cancer severity. The objective of this study was to examine the effect of fish oil (FO) supplementation in obesity-associated mammary tumorigenesis in the MMTV-neu(ndl)-YD5 mouse model of human epidermal growth factor receptor-2 positive BC. Female mice were fed one of three diets for 16 weeks: i) high fat diet [HF, % kacl: 41.2% lard, 18.7% corn oil (CO)], ii) an isocaloric HF plus menhaden FO diet (HF+FO, % kcal: 41.2 lard, 13.4% CO, 5.3% FO), iii) low fat diet (LF, % kcal: 4.7% lard, 6% CO). HF mice had increased body weight, visceral adipose weight and serum hormone concentrations (increased leptin and resistin; decreased adiponectin) versus LF, which was attenuated in the HF+FO group versus HF (P<.05). Compared to HF, tumor onset was delayed in HF+FO and LF mice (P<0.05). Compared to HF, HF+FO reduced mammary tumor multiplicity (-27%), tumor weight (-46%) and total tumor volume (-50%) (P<0.05). Additionally, HF+FO reduced mammary tumor multiplicity (-33%), tumor weight (-39%) and total tumor volume (-60%) versus LF. HF+FO improved mammary tumor apoptosis status with increased expression of pro-apoptotic Bad and decreased expression of anti-apoptotic Bcl-xLmediators versus HF (P<0.05). Additionally, HF+FO decreased tumor protein expression of activated Akt, NFκB p65 and STAT3, versus HF (P<0.05). Tumor mRNA expression of inflammatory mediators TNFα, IL-6 and leptin were reduced in HF+FO, whereas IL-10 expression was increased compared to HF (P<0.05). Collectively these results demonstrate the efficacy of FO supplementation for improving obesity-associated breast cancer outcomes.

Navy Bean Supplementation in Established High-Fat Diet-Induced Obesity Attenuates the Severity of the Obese Inflammatory Phenotype.

Cooked common beans (Phaseolus vulgaris) improve intestinal health in lean mice and attenuate intestinal dysbiosis and inflammation when consumed concurrent with obesity development. We determined the effects of a high-fat (HF) bean supplemented diet in mice with established obesity (induced by 12 weeks of HF diet (60% fat as kcal)) compared to obese mice consuming a HF or low-fat (LF) weight loss control diet. Obese C57BL/6 male mice remained consuming HF for eight weeks or were randomly switched from HF to an isocaloric HF with 15.7% cooked navy bean powder diet (HFàHFB) or LF (11% fat as kcal; HFàLF) (n = 12/group). HFàHFB improved the obese phenotype, including (i) fecal microbiome (increased Prevotella, Akkermansia muciniphila, and short-chain fatty acid levels), (ii) intestinal health (increased ZO-1, claudin-2, Muc2, Relmß, and Reg3γ expression), and (iii) reduced adipose tissue (AT) inflammatory proteins (NFκBp65, STAT3, IL-6, MCP-1, and MIP-1α), versus HF (p < 0.05). Conversely, HFàLF reduced body weight and circulating hormones (leptin, resistin, and PAI-1) versus HF and HFàHFB (p < 0.05); however, AT inflammation and intestinal health markers were not improved to the same degree as HFàHFB (p < 0.05). Despite remaining on a HF obesogenic diet, introducing beans in established obesity improved the obese phenotype (intestinal health and adipose inflammation) more substantially than weight loss alone.

Dietary long-chain n-3 PUFAs mitigate CD4+ T cell/adipocyte inflammatory interactions in co-culture models of obese adipose tissue.

Obese adipose tissue (AT) inflammation is partly driven by accumulation of CD4+ T helper (Th)1 cells and reduced Th2 and T regulatory subsets, which promotes macrophage chemotaxis and ensuing AT metabolic dysfunction. This study investigated CD4+ T cell/adipocyte cytokine-mediated paracrine interactions (cross talk) as a target for dietary intervention to mitigate obese AT inflammation. Using an in vitro co-culture model designed to recapitulate CD4+ T cell accumulation in obese AT (5% of stromal vascular cellular fraction), 3T3-L1 adipocytes were co-cultured with purified splenic CD4+ T cells from C57Bl/6 mice consuming one of two isocaloric diets containing either 10% w/w safflower oil (control, CON) or 7% w/w safflower oil+3% w/w fish oil (FO) for 4 weeks (n=8-11/diet). The FO diet provided 1.9% kcal from the long-chain (LC) n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid and docosahexaenoic acid, a dose that can be achieved by supplementation. Co-cultures were stimulated for 48 h with lipopolysaccharide (LPS) to mimic in vivo obese endotoxin levels or with conditioned media collected from LPS-stimulated visceral AT isolated from CON-fed mice. In both stimulation conditions, FO reduced mRNA expression and/or secreted protein levels of Th1 markers (T-bet, IFN-γ) and increased Th2 markers (GATA3, IL-4), concomitant with reduced inflammatory cytokines (IL-1ß, IL-6, IL-12p70, TNF-α), macrophage chemokines (MCP-1, MCP-3, MIP-1α, MIP-2) and levels of activated central regulators of inflammatory signaling (NF-κB, STAT-1, STAT-3) (P<.05). Therefore, CD4+ T cell/adipocyte cross talk represents a potential target for LC n-3 PUFAs to mitigate obese AT inflammation.

Sports-related concussions and subconcussive impacts in athletes: incidence, diagnosis, and the emerging role of EPA and DHA.

Sports-related concussions (SRC) are traumatic brain injuries induced as the result of a biomechanical force to the body that temporarily impair neurological functions. Not all traumatic impacts reach the threshold necessary to produce concussive symptoms; however, the culmination of these events is known as a subconcussive impact (SCI). Athletes who have been diagnosed with a SRC or those who accumulate multiple SCI have exhibited structural damage to the brain, impairments to learning and memory, and an increase in depressive symptoms. This area is rapidly evolving, and current clinical definitions of injury, diagnosis, and treatment of SRC and SCI are reviewed. In tandem, there is also growing research examining the role of nutrition in brain injuries, focusing primarily on n-3 polyunsaturated fatty acids (PUFA). The potential role of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in reducing inflammation and promoting recovery following brain injury are also reviewed. Overall, advancements in the evaluation of SRC and SCI coupled with n-3 PUFA supplementation show promise in the management of brain injuries, leading to better long-term health outcomes for athletes. Novelty SRC have garnered widespread attention due to the growing body of reported prevalence in youth and professional sports. Current definitions and protocol(s) for diagnosing SRC and SCI have improved, but still require further evaluation. n-3, EPA and DHA, reduce inflammation and promote recovery following brain injuries in experimental models.

CD8+ T cell/adipocyte inflammatory cross talk and ensuing M1 macrophage polarization are reduced by fish-oil-derived n-3 polyunsaturated fatty acids, in part by a TNF-α-dependent mechanism.

Obese visceral adipose tissue (AT) inflammation is driven by adipokine-mediated cross talk between CD8+ T cells and adipocytes, a process mitigated by long-chain (LC) n-3 polyunsaturated fatty acids (PUFA) but underlying mechanisms and ensuing effects on macrophage polarization status are unknown. Using an in vitro co-culture model that recapitulates the degree of CD8+ T cell infiltration reported in obese AT, 3T3-L1 adipocytes were co-cultured for 24 h with purified splenic CD8+ T cells from C57Bl/6 mice consuming either a 10% w/w safflower oil (control, CON) or 7% w/w safflower oil + 3% w/w fish oil (FO) diet for 4 weeks (n=8-10/diet). Co-cultured cells were in direct contact or in a contact-independent condition separated by a Transwell permeable membrane and stimulated with lipopolysaccharide (10 ng/ml) to mimic in vivo obese endotoxin levels. In contact-dependent co-cultures, FO reduced inflammatory (IL-6, TNFα, IFN-γ) and macrophage chemotactic (CCL2, CCL7, CCL3) mRNA expression and/or secreted protein, NF-κB p65 activation, ROS accumulation, NLRP3 inflammasome priming (Nlrp3, Il1ß mRNA) and activation (caspase-1 activity) compared to CON (P<.05). The anti-inflammatory action of FO was reproduced by the addition of a TNF-α neutralizing antibody (1 µg/ml) to CON co-cultures (CON/anti-TNF-α), albeit to a lesser degree. Conditioned media from FO and CON/anti-TNF-α co-cultures, in turn, reduced RAW 264.7 macrophage mRNA expression of M1 polarization markers (iNos, Cd11c, Ccr2) and associated inflammatory cytokines (Il6, Tnfα, Il1ß) compared to CON. These data suggest that inflammatory CD8+ T cell/adipocyte cross talk is partially attributable to TNF-α signaling, which can be mitigated by LC n-3 PUFA.

Fish oil supplementation to a high-fat diet improves both intestinal health and the systemic obese phenotype.

Impaired intestinal health characterized by a dysbiotic microbial community and a dysfunctional epithelial barrier contributes to host inflammation and metabolic dysfunction in obesity. Fish oil (FO)-derived n-3 polyunsaturated fatty acids have been shown to improve aspects of the obese phenotype; however, their effect on obese intestinal health is unknown. This study aimed to determine the effect of dietary FO on the intestinal microenvironment, including the microbial community and epithelial barrier, in a mouse model of high-fat diet induced obesity and metabolic dysfunction. Male C57BL/6 mice were fed (12 weeks) either a high-fat diet (HF, 60% fat as kcal) or an isocaloric HF supplemented with Menhaden FO (5.3% kcal, HF + FO). 16S rRNA sequencing was used to determine changes in fecal microbiota. Intestinal (ileum and colon) and epididymal adipose tissue RNA was used to assess biomarkers of barrier integrity and inflammatory status, respectively. Serum was used to assess adipokine concentrations and insulin resistance. HF + FO diet altered the fecal microbiota by decreasing the abundance of Firmicutes and increasing the abundance of members of the Bacteroidetes phyla, as well as increasing the abundance of antiobesogenic Akkermansia muciniphila, compared to HF. Intestinal epithelial barrier functions were improved by HF + FO evidenced by increased mRNA expression of tight junction components, antimicrobial defenses and mucus barrier components. HF + FO-fed mice exhibited improvements in homeostatic model assessment of insulin resistance, oral glucose tolerance and serum adipokine concentrations and epididymal mRNA expression (increased adiponectin and decreased leptin) versus HF. HF + FO improved obese intestinal health and attenuated metabolic dysfunction associated with obesity.

Navy bean supplemented high-fat diet improves intestinal health, epithelial barrier integrity and critical aspects of the obese inflammatory phenotype.

Obesity is associated with impaired intestinal epithelial barrier function and an altered microbiota community structure, which contribute to host systemic inflammation and metabolic dysfunction. Fiber-rich common beans (Phaseolus vulgaris) promote intestinal health (microbiota and host epithelial barrier integrity) in lean mice. The objective was to assess the intestinal health promoting effects of navy bean supplementation during high-fat (HF)diet-induced obesity. Male C57BL/6 mice were fed either a high-fat (HF) diet (60% of kcal from fat) or an isocaloric HF diet supplemented with 15.7% (by weight) cooked navy bean powder (HF+B) for 12 weeks. Compared to HF, the HF+B diet altered the fecal microbiota community structure (16S rRNA gene sequencing), most notably increasing abundance of Akkermansia muciniphila (+19-fold), whose abundance typically decreases in obese humans and rodents. Additionally, HF+B fecal abundance of carbohydrate fermenting, short chain fatty acid (SCFA) producing Prevotella (+332-fold) and S24-7 (+1.6-fold) and fecal SCFA levels were increased. HF+B improved intestinal health and epithelial barrier integrity versus HF, evidenced by reduced serum fluorescein isothiocyanate (FITC)-dextran concentration in an in vivo gut permeability test, and increased intestinal mRNA expression of tight junction components (ZO-1, occludin), anti-microbial defenses (Reg3γ, IgA, Defα5, Defß2) and mucins (Muc2). Additionally, HF+B improved the systemic obese phenotype via reduced serum HOMA-IR and leptin:adiponectin ratio, and locally via attenuation of epididymal adipose tissue crown-like structure formation, adipocyte size, and inflammatory transcription factor (NFκBp65 and STAT3) activation. Therefore, navy bean supplementation improved obese intestinal health (microbiota and epithelial barrier integrity) and attenuated the severity of the obese phenotype.

Research in nutritional supplements and nutraceuticals for health, physical activity, and performance: moving forward 1.

This Horizons is part of a series that identifies key, forward-thinking research questions and challenges that need to be addressed. Specifically, this Horizons paper discusses research in nutritional supplements and nutraceuticals for health, physical activity, and performance, and is the product of a discussion by an expert panel that took place in January 2018 prior to the Canadian Nutrition Society Thematic Conference "Advances in Sport Nutrition from Daily Living to High Performance Sport". The objective of this Horizons paper was to identify core considerations for future studies for this research area, and how scientists can be leaders in the field to ensure the best quality science is available for decision makers. It is strongly recommended that the various elements highlighted throughout this Horizons paper will increase the awareness of the significant before-, during-, and after-research due-diligence required to produce research of the highest quality. While it is recognized that many scientists will not be able to meet all of these aspects, it is nonetheless important to consider the points outlined and to recognize that those elements that are not met in studies may be significant limitations. Highlights Research questions that are hypothesis-driven are the strongest, and when combined with careful planning of the study, the result will often be of the best quality. Studies with a strong experimental design help discern between evidence-based findings and those that have not been substantiated.

Navy and black bean supplementation attenuates colitis-associated inflammation and colonic epithelial damage.

The enriched levels of nondigestible fermentable carbohydrates and phenolic compounds found in common beans can exert immunomodulatory effects within the colon that improve gut health and mitigate the severity of colitis-associated inflammatory pathology. Prior to acute colitis onset, C57Bl/6 mice were prefed isocaloric 20% cooked navy bean (NB) or black bean (BB) diets for 3 weeks and switched to control basal diet (BD) 24 h prior to colitis induction via 5-day exposure to dextran sodium sulfate (2% w/v in drinking water)+3 days of fresh water. The severity of the acute colitis phenotype was attenuated by bean prefeeding, evidenced by reduced colon tissue inflammatory transcription factor activation (NFκB, STAT3) and inflammatory mediator levels in the colon (IL-1ß, IL-6, IL-18 and MCP-1) and serum (TNFα, IL-6, IL-1ß, MCP-1) versus BD (P≤.05). Additionally, biomarkers of enhanced wound repair responses were increased by bean prefeeding including colon tissue protein levels of IL-22, IL-27 and activated (i.e., GTP-bound) Cdc42 and Rac1 versus BD (P≤.05). mRNA expressions of genes involved in normal colonic epithelial function and the promotion of epithelial barrier integrity, defense and/or restitution and wound closure including MUC1, RELMß, IgA and REG3γ were all increased in NB and BB prefed mice versus BD (P≤.05). Collectively, bean supplementation prior to colitis induction (i.e., mimicking disease relapse) primes the colonic microenvironment to attenuate the severity of the colitis inflammatory phenotype and maintain aspects of epithelial barrier function.

Marine fish oil is more potent than plant-based n-3 polyunsaturated fatty acids in the prevention of mammary tumors.

Marine-derived n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been shown to inhibit mammary carcinogenesis. However, evidence regarding plant-based α-linolenic acid (ALA), the major n-3 PUFA in the Western diet, remains equivocal. The objective of this study was to examine the effect of lifelong exposure to plant- or marine-derived n-3 PUFAs on pubertal mammary gland and tumor development in MMTV-neu(ndl)-YD5 mice. It is hypothesized that lifelong exposure to n-3 PUFA reduces terminal end buds during puberty leading to delayed tumor onset, volume and multiplicity. It is further hypothesized that plant-derived n-3 PUFAs will exert dose-dependent effects. Harems of MMTV-FVB males were bred with wild-type females and fed either a (1) 10% safflower (10% SF, n-6 PUFA, control), (2) 10% flaxseed (10% FS), (3) 7% safflower plus 3% flaxseed (3% FS) or (4) 7% safflower plus 3% menhaden (3% FO) diet. Female offspring were maintained on parental diets. Compared to SF, 10% FS and 3% FO reduced (P<.05) terminal end buds at 6 weeks and tumor volume and multiplicity at 20 weeks. A dose-dependent reduction of tumor volume and multiplicity was observed in mice fed 3% and 10% FS. Antitumorigenic effects were associated with altered HER2, pHER-2, pAkt and Ki-67 protein expression. Compared to 10% SF, 3% FO significantly down-regulated expression of genes involved in eicosanoid synthesis and inflammation. From this, it can be estimated that ALA was 1/8 as potent as EPA+DHA. Thus, marine-derived n-3 PUFAs have greater potency versus plant-based n-3 PUFAs.

Integrated Immunomodulatory Mechanisms through which Long-Chain n-3 Polyunsaturated Fatty Acids Attenuate Obese Adipose Tissue Dysfunction.

Obesity is a global health concern with rising prevalence that increases the risk of developing other chronic diseases. A causal link connecting overnutrition, the development of obesity and obesity-associated co-morbidities is visceral adipose tissue (AT) dysfunction, characterized by changes in the cellularity of various immune cell populations, altered production of inflammatory adipokines that sustain a chronic state of low-grade inflammation and, ultimately, dysregulated AT metabolic function. Therefore, dietary intervention strategies aimed to halt the progression of obese AT dysfunction through any of the aforementioned processes represent an important active area of research. In this connection, fish oil-derived dietary long-chain n-3 polyunsaturated fatty acids (PUFA) in the form of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been demonstrated to attenuate obese AT dysfunction through multiple mechanisms, ultimately affecting AT immune cellularity and function, adipokine production, and metabolic signaling pathways, all of which will be discussed herein.

Purified rutin and rutin-rich asparagus attenuates disease severity and tissue damage following dextran sodium sulfate-induced colitis.

SCOPE: This study investigated the effects of cooked whole asparagus (ASP) versus its equivalent level of purified flavonoid glycoside, rutin (RUT), on dextran sodium sulfate (DSS)-induced colitis and subsequent colitis recovery in mice. METHODS AND RESULTS: C57BL/6 male mice were fed an AIN-93G basal diet (BD), or BD supplemented with 2% cooked ASP or 0.025% RUT for 2 wks prior to and during colitis induction with 2% DSS in water for 7 days, followed by 5 days colitis recovery. In colitic mice, both ASP and RUT upregulated mediators of improved barrier integrity and enhanced mucosal injury repair (e.g. Muc1, IL-22, Rho-A, Rac1, and Reg3γ), increased the proportion of mouse survival, and improved disease activity index. RUT had the greatest effect in attenuating DSS-induced colonic damage indicated by increased crypt and goblet cell restitution, reduced colonic myeloperoxidase, as well as attenuated DSS-induced microbial dysbiosis (reduced Enterobacteriaceae and Bacteroides, and increased unassigned Clostridales, Oscillospira, Lactobacillus, and Bifidobacterium). CONCLUSION: These findings demonstrate that dietary cooked ASP and its flavonoid glycoside, RUT, may be useful in attenuating colitis severity by modulating the colonic microenvironment resulting in reduced colonic inflammation, promotion of colonic mucosal injury repair, and attenuation of colitis-associated microbial dysbiosis.

Fish-oil-derived n-3 polyunsaturated fatty acids reduce NLRP3 inflammasome activity and obesity-related inflammatory cross-talk between adipocytes and CD11b(+) macrophages.

Adipocyte-macrophage cross-talk propagates immune responses in obese adipose tissue (AT). Long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) mitigate inflammation, partly through up-regulation of adiponectin; however, specific mechanisms are unclear. We determined if adipocyte-macrophage cross-talk could be mitigated by dietary LC n-3 PUFA and if this was dependent on adiponectin-mediated signaling. We utilized an in vitro co-culture model mimicking the ratio of adipocytes:macrophages in obese AT, whereby 3T3-L1 adipocytes were co-cultured with splenic CD11b(+) macrophages from C57BL/6 mice fed high-fat control (HF-CON; 34% w/w fat) or fish oil diets (HF-FO; 34% w/w fat containing 7.6% w/w FO), as well as mice fed low-fat control (LF-CON; 10% w/w fat) or FO diets (LF-FO; 10% w/w fat containing 3% w/w FO). Co-culture conditions tested effects of soluble mediator-driven mechanisms (trans-well system), cell contact and low-dose lipopolysaccharide (LPS) mimicking acute or chronic inflammatory conditions. HF-FO macrophages from acute LPS-stimulated trans-well co-cultures had decreased mRNA expression of Casp1, Il1ß and Il18, as well as cellular caspase-1 activity compared to HF-CON macrophages (P≤.05). Moreover, adipocytes from acute LPS-stimulated HF-FO co-cultures had decreased caspase-1 activity and decreased IL-1ß/IL-18 levels following chronic LPS pretreatment compared to HF-CON co-cultures (P≤.05). Additionally, in contact co-cultures with adiponectin-neutralizing antibody, the FO-mediated modulation of NFκB activity and decrease in phosphorylated p65 NFκB, expression of NLRP3 inflammasome genes, M1 macrophage marker genes and inflammatory cytokine/chemokine secretion were controlled partly through adiponectin, while cellular caspase-1 activity and IL-1ß/1L-18 levels were decreased independently of adiponectin (P≤.05). LC n-3 PUFA may decrease the intensity of adipocyte-macrophage cross-talk to mitigate obesity-associated pathologies.

The delta 6 desaturase knock out mouse reveals that immunomodulatory effects of essential n-6 and n-3 polyunsaturated fatty acids are both independent of and dependent upon conversion.

Typically fatty acids (FA) exert differential immunomodulatory effects with n-3 [α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] and n-6 [linoleic acid (LA) and arachidonic acid (AA)] exerting anti- and pro-inflammatory effects, respectively. This over-simplified interpretation is confounded by a failure to account for conversion of the parent FA (LA and ALA) to longer-chain bioactive products (AA and EPA/DHA, respectively), thereby precluding discernment of the immunomodulatory potential of specific FA. Therefore, we utilized the Δ6-desaturase model, wherein knockout mice (D6KO) lack the Fads2 gene encoding for the rate-limiting enzyme that initiates FA metabolism, thereby providing a model to determine specific FA immunomodulatory effects. Wild-type (WT) and D6KO mice were fed one of four isocaloric diets differing in FA source (9weeks): corn oil (LA-enriched), arachidonic acid single cell oil (AA-enriched), flaxseed oil (ALA-enriched) or menhaden fish oil (EPA/DHA-enriched). Splenic mononuclear cell cytokine production in response to lipopolysaccharide (LPS), T-cell receptor (TCR) and anti-CD40 stimulation was determined. Following LPS stimulation, AA was more bioactive compared to LA, by increasing inflammatory cytokine production of IL-6 (1.2-fold) and TNFα (1.3-fold). Further, LPS-stimulated IFNγ production in LA-fed D6KO mice was reduced 5-fold compared to LA-fed WT mice, indicating that conversion of LA to AA was necessary for cytokine production. Conversely, ALA exerted an independent immunomodulatory effect from EPA/DHA and all n-3 FA increased LPS-stimulated IL-10 production versus LA and AA. These data definitively identify specific immunomodulatory effects of individual FA and challenge the simplified view of the immunomodulatory effects of n-3 and n-6 FA.

Diets enriched with cranberry beans alter the microbiota and mitigate colitis severity and associated inflammation.

Common beans are rich in phenolic compounds and nondigestible fermentable components, which may help alleviate intestinal diseases. We assessed the gut health priming effect of a 20% cranberry bean flour diet from two bean varieties with differing profiles of phenolic compounds [darkening (DC) and nondarkening (NDC) cranberry beans vs. basal diet control (BD)] on critical aspects of gut health in unchallenged mice, and during dextran sodium sulfate (DSS)-induced colitis (2% DSS wt/vol, 7 days). In unchallenged mice, NDC and DC increased (i) cecal short-chain fatty acids, (ii) colon crypt height, (iii) crypt goblet cell number and mucus content and (iv) Muc1, Klf4, Relmß and Reg3γ gene expression vs. BD, indicative of enhanced microbial activity and gut barrier function. Fecal 16S rRNA sequencing determined that beans reduced abundance of the Lactobacillaceae (Ruminococcus gnavus), Clostridiaceae (Clostridium perfringens), Peptococcaceae, Peptostreptococcaceae, Rikenellaceae and Pophyromonadaceae families, and increased abundance of S24-7 and Prevotellaceae. During colitis, beans reduced (i) disease severity and colonic histological damage, (ii) increased gene expression of barrier function promoting genes (Muc1-3, Relmß, and Reg3γ) and (iii) reduced colonic and circulating inflammatory cytokines (IL-1ß, IL-6, IFNγ and TNFα). Therefore, prior to disease induction, bean supplementation enhanced multiple concurrent gut health promoting parameters that translated into reduced colitis severity. Moreover, both bean diets exerted similar effects, indicating that differing phenolic content did not influence the endpoints assessed. These data demonstrate a proof-of-concept regarding the gut-priming potential of beans in colitis, which could be extended to mitigate the severity of other gut barrier-associated pathologies.

Anti-inflammatory and anti-chemotactic effects of dietary flaxseed oil on CD8(+) T cell/adipocyte-mediated cross-talk.

SCOPE: CD8(+) T cell/adipocyte paracrine interactions represent a critical step in the development of the obese inflammatory phenotype that is disrupted by long-chain n-3 PUFA. Our objective was to determine the effect of flaxseed-derived n-3 PUFA (α-linolenic acid) on these paracrine interactions. METHODS AND RESULTS: C57BL/6 mice were fed 3.5% flaxseed oil (FX) + 3.5% corn oil diet w/w or an isocaloric 7% corn oil w/w control diet (CON) for 3 wk. 3T3-L1 adipocytes and purified primary splenic CD8(+) T cells were cocultured at an obese cellular ratio (10% CD8(+) T cells) and LPS-stimulated (10 ng/mL mimicking obese circulating endotoxin levels) for 24 h. FX cocultures reduced (i) secreted IL-6, tumor necrosis factor α (TNF-α), macrophage chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 1α (MIP-1α), and RANTES (regulated on activation, normal T cell expressed and secreted) levels; (ii) activation of inflammatory transcription factors NFκB (nuclear factor kappa-light-chain-enhancer of activated B cell) p65 and signal transducer and activator of transcription-3 (STAT3); and (iii) RAW264.7 macrophage chemotaxis versus CON (p ≤ 0.05). Coculture of pre-inflamed adipocytes (10 ng/mL LPS, 24 h prior to CD8(+) T-cell addition) resulted in reduced secretion of IL-6, IL-1ß, MCP-1, MCP-3, MIP-1ß, and RANTES in FX cocultures versus CON (p ≤ 0.05). CONCLUSION: FX exerts an anti-chemotactic and anti-inflammatory effect on CD8(+) T cell/adipocyte paracrine interactions (cross-talk), which has the potential to mitigate macrophage chemotaxis which drives components of the obese phenotype.

A review of the effect of omega-3 polyunsaturated fatty acids on blood triacylglycerol levels in normolipidemic and borderline hyperlipidemic individuals.

Circulating levels of triacylglycerol (TG) is a recognized risk factor for developing cardiovascular disease, a leading cause of death worldwide. The Institute of Medicine and the American Heart Association both recommend the consumption of n-3 polyunsaturated fatty acids (PUFA), specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), to reduce serum TG in hyperlipidemic individuals. Additionally, a number of systematic reviews have shown that individuals with any degree of dyslipidemia, elevated serum TG and/or cholesterol, may benefit from a 20-30% reduction in serum TG after consuming n-3 PUFA derived from marine sources. Given that individuals with serum lipid levels ranging from healthy to borderline dyslipidemic constitute a large portion of the population, the focus of this review was to assess the potential for n-3 PUFA consumption to reduce serum TG in such individuals. A total of 1341 studies were retrieved and 38 clinical intervention studies, assessing 2270 individuals, were identified for inclusion in the current review. In summary, a 9-26% reduction in circulating TG was demonstrated in studies where ≥ 4 g/day of n-3 PUFA were consumed from either marine or EPA/DHA-enriched food sources, while a 4-51% reduction was found in studies where 1-5 g/day of EPA and/or DHA was consumed through supplements. Overall, this review summarizes the current evidence with regards to the beneficial effect of n-3 PUFA on circulating TG levels in normolipidemic to borderline hyperlipidemic, otherwise healthy, individuals. Thus demonstrating that n-3 PUFA may play an important role in the maintenance of cardiovascular health and disease prevention.

Fish-oil-derived n-3 PUFAs reduce inflammatory and chemotactic adipokine-mediated cross-talk between co-cultured murine splenic CD8+ T cells and adipocytes.

BACKGROUND: Obese adipose tissue (AT) inflammation is characterized by dysregulated adipokine production and immune cell accumulation. Cluster of differentiation (CD) 8+ T cell AT infiltration represents a critical step that precedes macrophage infiltration. n-3 (ω-3) Polyunsaturated fatty acids (PUFAs) exert anti-inflammatory effects in obese AT, thereby disrupting AT inflammatory paracrine signaling. OBJECTIVE: We assessed the effect of n-3 PUFAs on paracrine interactions between adipocytes and primary CD8+ T cells co-cultured at the cellular ratio observed in obese AT. METHODS: C57BL/6 mice were fed either a 3% menhaden fish-oil + 7% safflower oil (FO) diet (wt:wt) or an isocaloric 10% safflower oil (wt:wt) control (CON) for 3 wk, and splenic CD8+ T cells were isolated by positive selection (via magnetic microbeads) and co-cultured with 3T3-L1 adipocytes. Co-cultures were unstimulated (cells alone), T cell receptor stimulated, or lipopolysaccharide (LPS) stimulated for 24 h. RESULTS: In LPS-stimulated co-cultures, FO reduced secreted protein concentrations of interleukin (IL)-6 (-42.6%), tumor necrosis factor α (-67%), macrophage inflammatory protein (MIP) 1α (-52%), MIP-1ß (-62%), monocyte chemotactic protein (MCP) 1 (-23%), and MCP-3 (-19%) vs. CON, which coincided with a 74% reduction in macrophage chemotaxis toward secreted chemotaxins in LPS-stimulated FO-enriched co-culture-conditioned media. FO increased mRNA expression of the inflammatory signaling negative regulators monocyte chemoattractant 1-induced protein (Mcpip; +9.3-fold) and suppressor of cytokine signaling 3 (Socs3; +1.7-fold), whereas FO reduced activation of inflammatory transcription factors nuclear transcription factor κB (NF-κB) p65 and signal transducer and activator of transcription 3 (STAT3) by 27% and 33%, respectively. Finally, mRNA expression of the inflammasome components Caspase1 (-36.4%), Nod-like receptor family pyrin domain containing 3 (Nlrp3; -99%), and Il1b (-68.8%) were decreased by FO compared with CON (P ≤ 0.05). CONCLUSION: FO exerted an anti-inflammatory and antichemotactic effect on the cross-talk between CD8+ T cells and adipocytes and has implications in mitigating macrophage-centered AT-driven components of the obese phenotype.