Effect of Dietary Enrichment with n-3 Polyunsaturated Fatty Acids (PUFA) or n-9 PUFA on Arachidonate Metabolism in Vivo and Experimentally Induced Inflammation in Mice

The physiological and pathological properties of Mead acid, an endogenous multifunctional n-9 polyunsaturated fatty acid

Mead acid (MA, 5,8,11-eicosatrienoic acid) is an n-9 polyunsaturated fatty acid (PUFA) and a marker of essential fatty acid deficiency, but nonetheless generally draws little attention. MA is distributed in various normal tissues and can be converted to several specific lipid mediators by lipoxygenase and cyclooxygenase. Recent pathological and epidemiological studies on MA raise the possibility of its effects on inflammation, cancer, dermatitis and cystic fibrosis, suggesting it is an endogenous multifunctional PUFA. This review summarizes the biosynthesis, presence, metabolism and physiological roles of MA and its relation to various diseases, as well as the significance of MA in PUFA metabolism.

Immunity boosting nutraceuticals: Current trends and challenges

The immune function of the human body is highly influenced by the dietary intake of certain nutrients and bioactive compounds present in foods. The preventive effects of these bioactive ingredients against various diseases have been well investigated. Functional foods are consumed across various diverse cultures, in some form or the other, which provide benefits greater than the basic nutritional needs. Novel functional foods are being developed using novel bioactive ingredients such as probiotics, polyunsaturated fatty acids, and various phytoconstituents, which have a range of immunomodulatory properties. Apart from immunomodulation, these ingredients also affect immunity by their antioxidant, antibacterial, and antiviral properties. The global pandemic of Severe Acute Respiratory Syndrome Coronavirus-2 has forced the scientific community to race against time to find a proper and effective drug or a vaccine. In this review, various non-pharmacological interventions using nutraceuticals and functional foods have been discussed. PRACTICAL APPLICATIONS: Despite a plethora of research being undertaken to understand the immunity boosting properties of the various bioactive present in food, the findings are not translating to nutraceutical products in the market. Immunity has proved to be one of the most important factors for the health and well-being of an individual, especially when the world has been under the grip of the novel coronavirus Severe Acute Respiratory Syndrome Coronavirus-2. The anti-inflammatory properties of various nutraceuticals can come out as potential inhibitors of the various inflammatory processes such as cytokine storms, usually being observed in COVID 19. This review gives an insight into how various nutraceuticals can help in the prevention of various diseases through different mechanisms. The lack of awareness and proper clinical trials pose a challenge to the nutraceutical industry. This review will help and encourage researchers to further design and develop various functional foods, which might help in building immunity.

Dietary supplementation with arachidonic acid increases arachidonic acid content in paw, but does not affect arthritis severity or prostaglandin E2 content in rat adjuvant-induced arthritis model

BACKGROUND

Arachidonic acid (ARA) is an essential fatty acid and a major constituent of biomembranes. It is converted into various lipid mediators, such as prostaglandin E2 (PGE2), which is involved in the development of rheumatoid arthritis (RA). However, the effects of dietary ARA on RA are unclear. Our objective was to clarify the effects of dietary ARA on an experimental rat arthritis model.

METHODS

Lew rats were fed three contents of ARA diet (0.07%, 0.15% or 0.32% ARA in diet (w/w)), a docosahexaenoic acid (DHA) diet (0.32% DHA), or a control diet. After 4 weeks, arthritis was induced by injection of Freund's complete adjuvant into the hind footpad. We observed the development of arthritis for another 4 weeks, and evaluated arthritis severity, fatty acid and lipid mediator contents in the paw, and expression of genes related to lipid mediator formation and inflammatory cytokines. Treatment with indomethacin was also evaluated.

RESULTS

The ARA content of phospholipids in the paw was significantly elevated with dietary ARA in a dose-dependent manner. Dietary ARA as well as DHA did not affect arthritis severity (paw edema, arthritis score, and bone erosion). PGE2 content in the paw was increased by arthritis induction, but was not modified by dietary ARA. Dietary ARA did not affect the contents of other lipid mediators and gene expression of cyclooxygenase (COX)-1, COX-2, lipoxgenases and inflammatory cytokines. Indomethacin suppressed arthritis severity and PGE2 content in the paw.

CONCLUSION

These results suggest that dietary ARA increases ARA content in the paw, but has no effect on arthritis severity and PGE2 content of the paw in a rat arthritis model.

Nutrition and Polymyositis and Dermatomyositis

• Chronic muscle inflammation in polymyositis or dermatomyositis causes muscle weakness and fatigue.

• The chronic inflammation could lead to a catabolic state and additional loss of muscle mass.

• The chronic muscle inflammation could induce a metabolic myopathy.

• Body weight may not be reliable to measure muscle loss, rather measurement of body composition is recommended.

•For patients with polymyositis or dermatomyositis it is important to provide the body with the right amount of macronutrients and trace elements for maintenance and improvement of body functions.

• One recommendation is supplementation with calcium and vitamin D.

• Another recommendation is regular physical exercise that during limited periods can be combined with supplements such as creatine, if done under the care of a physician.

Contribution of polyunsaturated fatty acids to intestinal repair in protein-energy malnutrition

The aim of this study was to assess the effect of polyunsaturated fatty acids supplied in the diet on intestinal mucosa repair in a rat model of protein-energy malnutrition. Rats were fed either a standard semipurified diet or the same diet containing lactose as the only source of carbohydrate to cause protein-energy malnutrition. Diarrhea was induced within 24 h and was maintained for 2 weeks, after which both groups of rats were fed for 1 week either the standard diet or the standard diet supplemented with different sources of fatty acids, such as olive oil (OO), fish oil (FO), and purified phospholipids from pig brain (BPL). The lactose-enriched diet caused loss of enterocyte microvilli, lymphocyte infiltration, supranuclear cytoplasmic vesiculation, decreased number of goblet cells, low-density enlarged mitochondria, and less cristae. The FO diet improved the pathology score according to the histological and ultrastructural analysis, with an increased number of goblet cells, ratio of microvilli length to crypt depth, and percentage of intraepithelial lymphocytes compared to those found in rats with protein-energy malnutrition. We previously reported that chronic diarrhea depletes the antioxidant defense in rat intestine; we now show that both, the FO and the BPL diets, increase GSH levels in colon and that some antioxidant enzyme activities vary according to the source of fatty acids, with higher catalase and superoxide dismutase by the FO diet in jejunum, increased catalase by the BPL diet in jejunum, and elevated glutathione peroxidase by the OO diet in colon. The fatty acid profile of intestinal mucosa reflects the source of fat in the diet, with the lowest ratio of n-6/n-3 for rats fed the FO diet. These results suggest that dietary polyunsaturated fatty acids, particularly those in the n-3 series, may play an important role in intestinal repair in chronic diarrhea due to protein-energy malnutrition.

Early diet-induced non-alcoholic steatohepatitis in APOE2 knock-in mice and its prevention by fibrates

BACKGROUND/AIMS

The molecular mechanisms leading to Non-Alcoholic Steatohepatitis (NASH) are not fully understood. In mice, NASH can be inhibited by fenofibrate, a synthetic agonist for the nuclear receptor peroxisome proliferator activated receptor alpha, which regulates hepatic triglyceride metabolism. This study aimed to elucidate the relation between steatosis and inflammation in NASH in a human-like hyperlipidemic mouse model.

METHODS

Liver phenotype and gene expression were assessed in APOE2 knock-in mice that were fed a western-type high fat diet with or without co-administration of fenofibrate.

RESULTS

In response to a western diet, APOE2 knock-in mice developed NASH characterized by steatosis and inflammation. Strikingly, macrophage accumulation in the liver preceded the steatosis during progression of the disease. This phenotype was in line with gene expression patterns, which showed regulation of two major groups of genes, i.e. inflammatory and lipid genes. Fenofibrate treatment decreased hepatic macrophage accumulation and abolished steatosis. Moreover, a marked reduction in the expression of inflammatory genes occurred immediately after fenofibrate treatment.

CONCLUSIONS

These data indicate that inflammation might play an instrumental role during the development of NASH in this mouse model. Inhibition of NASH by fenofibrate may be due, at least in part, to its inhibitory effect on pro-inflammatory genes.