Chemotherapeutic Properties of n-3 Polyunsaturated Fatty Acids - Old Concepts and New Insights

Associations of the intake of individual and multiple fatty acids with depressive symptoms among adults in NHANES 2007-2018

BACKGROUND

Previous studies have mainly focused on the effects of individual fatty acids on depressive symptoms, while the combined effect of fatty acids on the risk of depressive symptoms has not yet been extensively reported. This study evaluate the associations between individual and multiple fatty acids with depressive symptoms in U.S. adults.

METHODS

Data sets were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007-2018 cycles. Both males and females aged above 18 years with complete information about dietary fatty acids intake, depression symptoms, and covariates were included. Weighted linear regression models were conducted to evaluate the relationships between individual fatty acid intake and depressive symptoms, and restricted cubic spline (RCS) models were utilized to explore the corresponding dose-response relationships. Additionally, we implemented the weighted quantile sum (WQS) regression and quantile g-computation (QGC) models to estimate the mixed effects of 19 fatty acids and identify the predominant types.

RESULTS

After multivariable adjustments, an increase of one unit in Linoleic acid (LA), Alpha-Linolenic Acid (ALA), Arachidonic acid (AA), Docosapentaenoic acid(DPA), Docosahexaenoic acid(DHA), was associated with a decrease in depressive scores by -0.021 (95 % CI: -0.039,-0.003, p = 0.021),-0.028 (95 % CI: -0.045,-0.011, p = 0.002),-0.026 (95 % CI: -0.044,-0.008, p = 0.005), -0.026 (95 % CI: -0.042,-0.009, p = 0.003), and - 0.022 (95 % CI: -0.041,-0.003, p = 0.022), respectively. However, a per unit increase in Hexanoic acid and Octanoic acid was associated with an increase in depressive scores of 0.020 (95 % CI: 0.002,0.038, p = 0.029) and 0.026 (95 % CI: 0.004,0.048, p = 0.020), respectively. Meanwhile, significant dose-response relationships were supported by the RCS models. As for the mixed effects, both WQS and QGC models demonstrated that the mixture of polyunsaturated fatty acids (PUFAs) was inversely related to depressive symptoms, and ALA and DPA were the most critical contributors. DHA was negatively correlated with depressive symptoms in WQS analysis, but positively correlated with depressive symptoms in QGC analysis.

LIMITATIONS

The cross-sectional design limits our ability to establish causality, and 24-hour dietary recall can lead to potential inaccuracies reflecting participants' true eating habits.

CONCLUSION

Our study suggests that the single effects of each PUFA were inversely associated with depressive symptoms, except for octadecatetraenoic acid. Moreover, higher combined intake of dietary PUFAs is inversely associated with depressive symptoms in U.S. adults. Among the mixed effects of PUFAs, ALA and DPA may play predominant roles. However, DHA mixed with other fatty acids may have different effects on depressive symptoms, and further study is needed.

Chemoprotective epigenetic mechanisms in a colorectal cancer model: Modulation by n-3 PUFA in combination with fermentable fiber

Colorectal cancer is the third major cause of cancer-related mortality in both men and women worldwide. The beneficial role of n-3 polyunsaturated fatty acids (PUFA) in preventing colon cancer is substantiated by experimental, epidemiological, and clinical data. From a mechanistic perspective, n-3 PUFA are pleiotropic and multifaceted with respect to their molecular mechanisms of action. For example, this class of dietary lipid uniquely modulates membrane and nuclear receptors, sensors/ion channels, and membrane structure/cytoskeletal function, thereby regulating signaling processes that influence patterns of gene expression and cell phenotype. In addition, n-3 PUFA can synergize with other potential chemoprotective agents known to reprogram the chromatin landscape, such as the fermentable fiber product, butyrate. Nutri-epigenomics is an emerging field of research that is focused on the interaction between nutrition and epigenetics. Epigenetics refers to a group of heterogeneous processes that regulate transcription without changing the DNA coding sequence, ranging from DNA methylation, to histone tail modifications and transcription factor activity. One implication of the nutri-epigenome is that it may be possible to reprogram epigenetic marks that are associated with increased disease risk by nutritional or lifestyle interventions. This review will focus on the nutri-epigenomic role of n-3 PUFA, particularly DHA, as well as the combinatorial effects of n-3 PUFA and fermentable fiber in relation to colon cancer.

[Pharmaconutrition: pharmacological approach to nutrition therapy]

Reviewing the literature of nutrition therapy one can conclude that during the last decade the pharmacological action of several nutrients has been demonstrated. However, research activity is still at the beginning and it could be verified in a restricted number of nutrients only that in which conditions (illnesses), dose and duration we can expect therapeutic effect in addition to nutrition. The examples of glutamine, arginine, taurine, leucine, ω-3 fatty acids, however, support the possibility that complex reactions and treatment results observed in certain patients are not purely due to nutritional support but the consequence of additional pharmacological action as well. Evaluation of results of therapeutic intervention is especially difficult because in the everyday practice physicians try to use several therapeutic modalities that can be beneficial for the patient. Therefore, retrospective separation of beneficial components of the therapeutic agents is almost impossible. Only well designed, randomized and multicentric studies can verify specific therapeutic action of certain ingredients ie. nutrients.

Dietary fish oil and DHA down-regulate antigen-activated CD4+ T-cells while promoting the formation of liquid-ordered mesodomains

We have demonstrated previously that n-3 PUFA endogenously produced by fat-1 transgenic mice regulate CD4+ T-cell function by affecting the formation of lipid rafts, liquid-ordered mesodomains in the plasma membrane. In the present study, we tested the effects of dietary sources of n-3 PUFA, i.e. fish oil (FO) or purified DHA, when compared with an n-6 PUFA-enriched maize oil control diet in DO11.10 T-cell receptor transgenic mice. Dietary n-3 PUFA were enriched in CD4+ T-cells, resulting in the increase of the n-3:n-6 ratio. Following antigen-specific CD4+ T-cell activation by B-lymphoma cells pulsed with the ovalbumin 323-339 peptide, the formation of liquid-ordered mesodomains at the immunological synapse relative to the whole CD4+ T-cell, as assessed by Laurdan labelling, was increased (P< 0·05) in the FO-fed group. The FO diet also suppressed (P< 0·05) the co-localisation of PKCθ with ganglioside GM1 (monosialotetrahexosylganglioside), a marker for lipid rafts, which is consistent with previous observations. In contrast, the DHA diet down-regulated (P< 0·05) PKCθ signalling by moderately affecting the membrane liquid order at the immunological synapse, suggesting the potential contribution of the other major n-3 PUFA components of FO, including EPA.

Docosahexaenoic fatty acid (DHA) in the regulation of colon cell growth and cell death: a review

BACKGROUND

Experimental, epidemiological and clinical data substantiate the beneficial role of n-3 polyunsaturated fatty acids (PUFAs) in preventing inflammation and cancer of the colon. This review covers the unsaturated docosahexaenoic fatty acid (DHA), describes some of its important cellular and molecular mechanisms, its interaction with another dietary lipid, butyrate and with endogenous apoptotic regulators of the tumour necrosis factor (TNF) family. We also discuss the clinical impact of this knowledge and the use of these lipids in colon cancer prevention and treatment.

RESULTS

From the literature, DHA has been shown to suppress the growth, induce apoptosis in colon cancer cells in vitro and decrease the incidence and growth of experimental tumours in vivo. Based on these data and our own experimental results, we describe and discuss the possible mechanisms of DHA anticancer effects at various levels of cell organization. We show that DHA can sensitize colon cancer cells to other chemotherapeutic/chemopreventive agents and affect the action of physiological apoptotic regulators of the TNF family.

CONCLUSION

Use of n-3 PUFAs could be a relatively non-toxic form of supportive therapy for improving colon cancer treatment and slowing down or preventing its recurrence. However, it is necessary to use them with caution, based on solid scientific evidence of their mechanisms of action from the molecular to the cellular and organism levels.

Evaluation of the relationship between endometriosis and omega-3 and omega-6 polyunsaturated fatty acids

BACKGROUND

Endometriosis is a common chronic inflammation causing major problems including infertility. The role of omega-3 and omega-6 fatty acids as their potential anti-inflammatory effects in endometriosis needs to be further explored. The objective of this study was to compare serum phospholipid fatty acid profile in endometriosis patients with controls, and to explore the correlation of this profile with the severity of the disease.

METHODS

Sixty-four endometriosis patients and 74 control women, in reproductive age, participated in this study. Among the endometriosis patients, 19 cases were in stage I, 27 cases in stage II, 8 cases in stage III, and 10 cases in stage IV. Each patient underwent laparoscopy. Before surgery, 5 ml of blood was obtained. After extraction of the total lipids, serum total phospholipid fraction was isolated by thin layer chromatography. Fatty acid composition of the phospholipid fraction was determined by gas chromatography and the resulted profile was compared in endometriosis patients and controls. The profile was also compared in the endometriosis group based on the severity of disease.

RESULTS

Stearic acid was significantly lower in the endometriosis group as compared to controls (P= 0.030). No other fatty acid compositions were significantly different between patients and controls. Serum ratio of eicosapentaenoic acid (EPA) to arachidonic acid (AA) was in reasonable correlation with the severity of endometriosis (r = 0.34, P = 0.006).

CONCLUSION

According to these findings, levels of fatty acids in serum total phospholipids seem not to be a marker for endometriosis, but the EPA to AA ratio was a relevant factor indicating severity of illness.

n-3 polyunsaturated fatty acids suppress phosphatidylinositol 4,5-bisphosphate-dependent actin remodelling during CD4+ T-cell activation

n-3 PUFA (polyunsaturated fatty acids), i.e. DHA (docosahexaenoic acid), found in fish oil, exhibit anti-inflammatory properties; however, the molecular mechanisms remain unclear. Since PtdIns(4,5)P2 resides in raft domains and DHA can alter the size of rafts, we hypothesized that PtdIns(4,5)P2 and downstream actin remodelling are perturbed by the incorporation of n-3 PUFA into membranes, resulting in suppressed T-cell activation. CD4+ T-cells isolated from Fat-1 transgenic mice (membranes enriched in n-3 PUFA) exhibited a 50% decrease in PtdIns(4,5)P2. Upon activation by plate-bound anti-CD3/anti-CD28 or PMA/ionomycin, Fat-1 CD4+ T-cells failed to metabolize PtdIns(4,5)P2. Furthermore, actin remodelling failed to initiate in Fat-1 CD4+ T-cells upon stimulation; however, the defect was reversed by incubation with exogenous PtdIns(4,5)P2. When Fat-1 CD4+ T-cells were stimulated with anti-CD3/anti-CD28-coated beads, WASP (Wiskott-Aldrich syndrome protein) failed to translocate to the immunological synapse. The suppressive phenotype, consisting of defects in PtdIns(4,5)P2 metabolism and actin remodelling, were recapitulated in CD4+ T-cells isolated from mice fed on a 4% DHA triacylglycerol-enriched diet. Collectively, these data demonstrate that n-3 PUFA, such as DHA, alter PtdIns(4,5)P2 in CD4+ T-cells, thereby suppressing the recruitment of WASP to the immunological synapse, and impairing actin remodelling in CD4+ T-cells.

Serum phospholipid fatty acids and prostate cancer risk: results from the prostate cancer prevention trial

Inflammation may be involved in prostate cancer development and progression. This study examined the associations between inflammation-related phospholipid fatty acids and the 7-year-period prevalence of prostate cancer in a nested case-control analysis of participants, aged 55-84 years, in the Prostate Cancer Prevention Trial during 1994-2003. Cases (n = 1,658) were frequency matched to controls (n = 1,803) on age, treatment, and prostate cancer family history. Phospholipid fatty acids were extracted from serum, and concentrations of ω-3, ω-6, and trans-fatty acids (TFAs) were expressed as proportions of the total. Logistic regression models estimated odds ratios and 95% confidence intervals of associations of fatty acids with prostate cancer by grade. No fatty acids were associated with low-grade prostate cancer risk. Docosahexaenoic acid was positively associated with high-grade disease (quartile 4 vs. 1: odds ratio (OR) = 2.50, 95% confidence interval (CI): 1.34, 4.65); TFA 18:1 and TFA 18:2 were linearly and inversely associated with risk of high-grade prostate cancer (quartile 4 vs. 1: TFA 18:1, OR = 0.55, 95% CI: 0.30, 0.98; TFA 18:2, OR = 0.48, 95% CI: 0.27, 0.84). The study findings are contrary to those expected from the pro- and antiinflammatory effects of these fatty acids and suggest a greater complexity of effects of these nutrients with regard to prostate cancer risk.

Eicosapentaenoic acid disrupts the balance between Tregs and IL-17+ T cells through PPARγ nuclear receptor activation and protects cardiac allografts

Eicosapentaenoic acid (EPA) is one of n-3 polyunsaturated fatty acids that possesses a wide array of anti-inflammatory effects but its effects, on transplantation in general and on Tregs and IL-17(+) T cells in particular, are not well studied. We treated recipient mice of heart transplantation with EPA and examined the effect of EPA on the ratio of Tregs/IL-17(+) T cells in an allogeneic heart transplant model. The hearts from BALB/c (H-2d) mice were transplanted into C57BL/6 (H-2b) mice, and the recipients were administered EPA (500 mg/kg/d, 250 mg/kg/d, or 100 mg/kg/d) from d 1 to 3 post-transplant. The survival of cardiac allografts in mice treated with EPA was significantly protracted. Further examination of donor hearts in EPA-treated group demonstrated that infiltrating Foxp3(+) T cells were increased, IL-17(+) T cells were decreased, and expression of PPARγ was up-regulated. In mixed lymphocytes reaction (MLR), incubation with EPA significantly inhibited the proliferation of IL-17(+) T cells and promoted the proliferation of Tregs, while PPARγ antagonists GW9662 could reverse the results. Our study demonstrated that EPA can effectively protect cardiac allografts and disrupt the balance between Tregs and IL-17(+) T cells in a murine model. This effect is partially mediated by PPARγ nuclear receptor activation.