Association of Polyunsaturated Fatty Acid Intake on Inflammatory Gene Expression and Multiple Sclerosis: A Systematic Review and Meta-Analysis

Association between Omega-3 fatty acids and autoimmune disease: Evidence from the umbrella review and Mendelian randomization analysis

BACKGROUND

Autoimmune diseases are a group of disorders characterized by abnormal immune responses that mistakenly target and attack healthy cells, tissues, and organs, resulting in inflammation and tissue damage. Omega-3 fatty acids possess anti-inflammatory activities and may decrease abnormal immune activity. However, the role of omega-3 fatty acids in various autoimmune diseases is still unclear. This umbrella review and Mendelian randomization (MR) study aims to summarize the highest available evidence on omega-3 fatty acids and autoimmune disease.

METHODS

We conducted an umbrella review by searching electronic databases to identify systematic reviews and meta-analyses. The selection criteria included systematic reviews with or without meta-analysis, which evaluated omega-3 fatty acids as the exposure and autoimmune disease as the outcome variable. Two authors independently assessed the overlapping and quality of the reviews using the AMSTAR-2 tool. We also performed MR studies to investigate the potential causal effect of fatty acids on the risk of various autoimmune diseases, utilizing data from the meta-analysis of the UKB-TOPMed and FinnGen cohorts.

RESULT

The umbrella review identified 21 studies (8 systematic reviews and 13 meta-analyses) on 9 autoimmune diseases and 30 diseases in the MR study. AMSTAR 2 categorized the quality of evidence in six studies as critically low, six studies as low, eight studies as moderate, and one as high-quality evidence. The consistent result between the review and the MR study demonstrated the benefit of omega-3 fatty acids on rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Additionally, in our summary review, omega-3 fatty acids can improve disease activity and inflammation biomarkers; however, MR studies provided no consistent evidence for the causal effects of omega-3 fatty acids on psoriasis, multiple sclerosis (MS), type 1 diabetes (T1D), IgA nephropathy (IgAN), juvenile idiopathic arthritis (JIA), Crohn's disease (CD), and ulcerative colitis (UC).

CONCLUSION

The current study presented solid evidence highlighting the advantageous impact of omega-3 fatty acids on SLE and RA. This was achieved through the reduction of disease risk, the decrease of disease activity, and the mitigation of inflammatory biomarkers. To stratify another autoimmune illness, it is necessary to carry out rigorous evaluations to surpass the existing findings and enhance understanding in this domain.

RETRACTED: Ghasemi Darestani et al. Association of Polyunsaturated Fatty Acid Intake on Inflammatory Gene Expression and Multiple Sclerosis: A Systematic Review and Meta-Analysis. Nutrients 2022, 14, 4627

The Journal retracts and amends the authorship of the article "Association of Polyunsaturated Fatty Acid Intake on Inflammatory Gene Expression and Multiple Sclerosis: A Systematic Review and Meta-Analysis" [...].

Exploration of potential biomarkers for prurigo nodularis based on plasma-metabolome analysis

Prurigo nodularis (PN) is a chronic and debilitating skin disease with severe itching that negatively impacts patients' quality of life and mental state. However, the treatment options for PN remain limited. Global metabolomics analysis can offer effective information on energy metabolism, pathogenesis and potential diagnostic biomarkers. No study on metabolomic analysis of PN has been reported. To further understand the mechanisms of PN and analyse the plasma metabolite profiles in patients with PN. Targeted-metabolome analysis of 306 metabolites in plasma from 18 patients with PN and 19 healthy controls was performed using Liquid Chromatography-tandem Mass Spectrometer analysis. We identified 31 differential metabolites. Most acylcarnitines, long-chain fatty acids, alpha-aminobutyric acid, hydroxybutyric acid and lactic acid among these metabolites were up-regulated in patients with PN; in contrast, glucaric acid, suberic acid, bile acid derivatives and most amino acids were down-regulated. Positive correlations exist between glucaric acid and itching severity and acylcarnitines and insomnia. Suberic acid and the Investigator's Global Assessment (IGA) scores correlate negatively. Metabolite variation reflects the dysregulation of energy metabolism and chronic systematic inflammation in PN. Several metabolites, such as glucaric acid, suberic acid and acylcarnitines, merit further study as potential biomarkers of disease severity in PN.

Natural products in atherosclerosis therapy by targeting PPARs: a review focusing on lipid metabolism and inflammation

Inflammation and dyslipidemia are critical inducing factors of atherosclerosis. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and control the expression of multiple genes that are involved in lipid metabolism and inflammatory responses. However, synthesized PPAR agonists exhibit contrary therapeutic effects and various side effects in atherosclerosis therapy. Natural products are structural diversity and have a good safety. Recent studies find that natural herbs and compounds exhibit attractive therapeutic effects on atherosclerosis by alleviating hyperlipidemia and inflammation through modulation of PPARs. Importantly, the preparation of natural products generally causes significantly lower environmental pollution compared to that of synthesized chemical compounds. Therefore, it is interesting to discover novel PPAR modulator and develop alternative strategies for atherosclerosis therapy based on natural herbs and compounds. This article reviews recent findings, mainly from the year of 2020 to present, about the roles of natural herbs and compounds in regulation of PPARs and their therapeutic effects on atherosclerosis. This article provides alternative strategies and theoretical basis for atherosclerosis therapy using natural herbs and compounds by targeting PPARs, and offers valuable information for researchers that are interested in developing novel PPAR modulators.

Evaluating the Impact of Omega-3 Fatty Acid (SolowaysTM) Supplementation on Lipid Profiles in Adults with PPARG Polymorphisms: A Randomized, Double-Blind, Placebo-Controlled Trial

Emerging evidence suggests that PPARG gene polymorphisms may influence lipid metabolism and cardiovascular risk, with omega-3 fatty acids proposed to modulate these effects. This study aims to assess the effects of fish oil supplementation on cardiovascular markers among adults with PPARG gene polymorphisms in a randomized, double-blind, placebo-controlled trial. A cohort of 102 patients with LDL-C 70-190 mg/dL was randomized to receive either 2000 mg of omega-3 fatty acids or a placebo daily for 90 days. In the omega-3 group with PPARG polymorphisms, LDL-C was reduced by 15.4% (95% CI: -19.8% to -11.0%), compared with a 2.6% decrease in the placebo group (95% CI: -4.1% to -1.1%; p < 0.01). In the omega-3 group without PPARG polymorphisms, LDL-C was reduced by 3.7% (95% CI: -6.9% to -0.6%), not significantly different from the placebo group's reduction of 2.9% (95% CI: -5.1% to -0.8%; p = 0.28). The reduction in LDL-C was notably 11.7% greater in those with PPARG polymorphisms than in those without (95% CI: -19.3% to -4.0%; p < 0.01). Triglycerides decreased by 21.3% in omega-3 recipients with PPARG polymorphisms (95% CI: -26.5% to -16.2%; p < 0.01), with no significant changes in HDL-C, total cholesterol, or hsCRP levels in any groups. Minor allele frequencies and baseline characteristics were comparable, ensuring a balanced genetic representation. Omega-3 fatty acids significantly reduce LDL-C and triglycerides in carriers of PPARG polymorphisms, underlining the potential for genetic-driven personalization of cardiovascular interventions.

Modulation of Gut Microbiome Community Mitigates Multiple Sclerosis in a Mouse Model: The Promising Role of Palmaria palmata Alga as a Prebiotic

BACKGROUND

Red marine algae have shown the potential to reduce inflammation, influence microbiota, and provide neuroprotection.

OBJECTIVE

To examine the prebiotic properties of Palmaria palmata aqueous extract (Palmaria p.) and its potential as a neuroprotective agent in multiple sclerosis (MS).

METHODS

eighty-eight adult Swiss mice were divided into four male and four female groups, including a control group (distilled water), Palmaria p.-treated group (600 mg/kg b.w.), cuprizone (CPZ)-treated group (mixed chow 0.2%), and a group treated with both CPZ and Palmaria p. The experiment continued for seven weeks. CPZ treatment terminated at the end of the 5th week, with half of the mice sacrificed to assess the demyelination stage. To examine the spontaneous recovery, the rest of the mice continued until the end of week seven. Behavioral (grip strength (GS) and open field tests (OFT)), microbiome, and histological assessments for general morphology of corpus callous (CC) were all conducted at the end of week five and week 7.

RESULTS

Palmaria p. can potentially protect against CPZ-induced MS with variable degrees in male and female Swiss mice. This protection was demonstrated through three key findings: (1) increased F/B ratio and expansion of the beneficial Lactobacillus, Proteobacteria, and Bactriodia communities. (2) Protection against the decline in GS induced by CPZ and prevented CPZ-induced anxiety in OFT. (3) Preservation of structural integrity.

CONCLUSIONS

Because of its propensity to promote microbiota alterations, its antioxidant activity, and its content of -3 fatty acids, Palmaria p. could be a promising option for MS patients and could be beneficial as a potential probiotic for the at-risk groups as a preventive measure against MS.

Impairment of Endogenous Synthesis of Omega-3 DHA Exacerbates T-Cell Inflammatory Responses

Omega-3 (ω-3) polyunsaturated fatty acids, including docosahexaenoic acid (DHA), are involved in numerous biological processes and have a range of health benefits. DHA is obtained through the action of elongases (ELOVLs) and desaturases, among which Elovl2 is the key enzyme involved in its synthesis, and can be further metabolized into several mediators that regulate the resolution of inflammation. Our group has recently reported that ELOVL2 deficient mice (Elovl2^-/-) not only display reduced DHA levels in several tissues, but they also have higher pro-inflammatory responses in the brain, including the activation of innate immune cells such as macrophages. However, whether impaired synthesis of DHA affects cells of adaptive immunity, i.e., T lymphocytes, is unexplored. Here we show that Elovl2^-/- mice have significantly higher lymphocytes in peripheral blood and that both CD8+ and CD4+ T cell subsets produce greater amounts of pro-inflammatory cytokines in both blood and spleen compared to wild type mice, with a higher percentage of cytotoxic CD8+ T cells (CTLs) as well as IFN-γ-producing Th1 and IL-17-producing Th17 CD4+ cells. Furthermore, we also found that DHA deficiency impacts the cross-talk between dendritic cells (DC) and T cells, inasmuch as mature DCs of Elovl2^-/- mice bear higher expression of activation markers (CD80, CD86 and MHC-II) and enhance the polarization of Th1 and Th17 cells. Reintroducing DHA back into the diets of Elovl2^-/- mice reversed the exacerbated immune responses observed in T cells. Hence, impairment of endogenous synthesis of DHA exacerbates T cell inflammatory responses, accounting for an important role of DHA in regulating adaptive immunity and in potentially counteracting T-cell-mediated chronic inflammation or autoimmunity.