Physiological difference between free and triglyceride-type conjugated linoleic acid on the immune function of C57BL/6N mice

Conjugated Linolenic Acid (CLnA) vs Conjugated Linoleic Acid (CLA): A Comprehensive Review of Potential Advantages in Molecular Characteristics, Health Benefits, and Production Techniques

Conjugated linoleic acid (CLA) has been extensively characterized due to its many biological activities and health benefits, but conjugated linolenic acid (CLnA) is still not well understood. However, CLnA has shown to be more effective than CLA as a potential functional food ingredient. Current research has not thoroughly investigated the differences and advantages between CLnA and CLA. This article compares CLnA and CLA based on molecular characteristics, including structural, chemical, and metabolic characteristics. Then, the in vivo research evidence of CLnA on various health benefits is comprehensively reviewed and compared with CLA in terms of effectiveness and mechanism. Furthermore, the potential of CLnA in production technology and product protection is analyzed. In general, CLnA and CLA have similar physicochemical properties of conjugated molecules and share many similarities in regulation effects and pathways of various health benefits as well as in the production methods. However, their specific properties, regulatory capabilities, and unique mechanisms are different. The superior potential of CLnA must be specified according to the practical application patterns of isomers. Future research should focus more on the advantageous characteristics of different isomers, especially the effectiveness and safety in clinical applications in order to truly exert the potential value of CLnA.

Selective synthesis of partial glycerides of conjugated linoleic acids via modulation of the catalytic properties of lipases by immobilization on different supports

Lipases B from Candida antarctica (CALB), Rhizomucor miehei (RML) and Thermomyces lanuginosus (TLL) were immobilized on octadecyl methacylate (OM) or octadecyl methacrylate (OMC) beads. Their specific activity and regioselectivity were studied in the synthesis of conjugated linoleic acid (CLA) partial glycerides, which presented nutraceutical properties. TLL derivatives were poor catalysts. Novozym® 435 was much better than Lipozyme® RM IM. RML activity (a GRAS enzyme) was modulated via immobilization. After only 3 h, OM-RML gave the highest CLA conversion (54% at 40 °C with 1:3 M ratio of glycerol to CLA). OM-RML reduced by a factor of 3.12 and 1.16 the activation energy of the reaction with Lipozyme® RM IM and Novozym® 435, respectively. The new GRAS preparation OM-RML brings forth an optimal regioselective preparation of sn-1 mono and sn-1,3 diacylglycerols rich in CLA, with a ratio of sn-1,3/sn-1,2 regioisomers of 21.8, compared to 2.3 for Novozym® 435.

Development of multifunctional foods

Foods contain various biologically active substances with extent physiological effects. Among them, some substances, such as dietary fibers, polyunsaturated fatty acids, and antioxidants, exert multiple activities. In addition, combinational uses of some components, such as sesamin and α-tocopherol, enhance their biological effects each other. The expression of multiple effect leads to the production of multifunctional foods which prevent the occurrence of various diseases. Furthermore, synergic effects between biologically active substances allow us to decrease the dose of each component, which lead to the improvement of safety and reduction of production cost of multifunctional foods. To use these active components for human health, studies on their adsorption and transportation are important, since distribution of some components, such as tocotrienols, is limited to some tissues. In addition, extent safety studies are essential to use artificially synthesized substances such as 10t, 12c derivative of conjugated linoleic acid for human health.

Strategies for Producing and Incorporating Conjugated Linoleic Acid–Rich Oils in Foods

Conjugated linoleic acid (CLA) is in ruminant-derived foods and is known to combat obesity-related diseases. However, CLA levels in a healthy diet are too low to produce a clinical effect. Therefore, CLA has been produced by linoleic isomerization through fermentation and chemical catalysis. Many of these techniques are not practical for food production, but a recent development has enabled production of CLA-rich triglyceride vegetable oils from high linoleic acid oils by a minor modification of conventional food-oil processing techniques. These oils were used to produce common lipid-based food, such as margarine, shortenings, and salad dressings, whose quality was enhanced by the presence of CLA-rich oil and provided a significant CLA source. Meat and egg CLA content and subsequent food quality can also be increased by addition of dietary CLA. However, consumer awareness of CLA benefits needs to increase prior to commercial-scale production of CLA-rich oil.

Effects of Dietary Punica granatum L. By-products on Performance, Immunity, Intestinal and Fecal Microbiology, and Odorous Gas Emissions from Excreta in Broilers

The fruit Punica granatum L. has been used for years in traditional medicine owing to the presence of several phytobiotics with antimicrobial and immunomodulatory properties. This study investigated the effects of dietary supplementation with Punica granatum L. by-products (PGB) on performance, immunity, intestinal and excreta microflora, and odorous gas emissions from excreta of broiler chickens. Three experimental diets containing 0, 0.5 and 1.0% PGB were fed to 240 one-day-old broiler chicks until 35 days. Dietary PGB linearly reduced the average daily feed intake and feed conversion ratio of broilers. Supplementation with 1% PGB led to a linear increase in the relative weight of the spleen and bursa of Fabricius. The concentration of serum IgA and IgG increased linearly in response to dietary PGB. In the ileal digesta, the concentration of Saccharomyces cerevisiae increased linearly and quadratically in response to dietary PGB. Moreover, dietary PGB led to a linear decrease in Escherichia coli and Salmonella spp. alongside reducing the pH of the ileal digesta. In the cecal digesta, the concentration of Bacillus bacteria increased linearly in response to both levels of dietary PGB, while the concentrations of E. coli and Salmonella decreased when the diet was supplemented with 1% PGB, as did cecal pH. At 35 day, both levels of PGB increased the concentration of fecal Bacillus, whereas only 1% PGB increased the concentration of S. cerevisiae at 21 day. Increasing levels of PGB induce a linear reduction in fecal E. coli at 21 and 35 day, whereas Salmonella only at 21 day. Regarding the average of 48 h, dietary PGB effectively reduced the emissions of ammonia and methanethiol from broiler excreta. In conclusion, the results suggest that, dietary PGB improved immunity and the intestinal microbial ecosystem of broilers along with reduced odorous gas emissions from excreta.

An array of possibilities in cancer research using cytokine antibody arrays

Protein arrays have shown potential applications in cancer research. After several decades of research, it has become evident that many cytokines are central to the development of cancer and its treatment. Cytokine antibody arrays that have been designed to simultaneously detect multiple cytokines are not only available, but show a diversity of applications in the study of many diseases in addition to cancer. This review will focus on the implementation of cytokine antibody arrays in many aspects of cancer research, such as biomarker discovery, molecular mechanisms of cancer development, preclinical studies and the effects of cancer compounds.

Free fatty acid and triacylglycerol forms of CLA isomers are not incorporated equally in the liver but do not lead to differences in bone density and biomarkers of bone metabolism

Few studies have compared differences between conjugated linoleic acid (CLA) in triacylglycerol (TG) and free fatty acid (FFA) form. This study assessed differences in liver incorporation, mineral mass balance, bone density, and biomarkers of bone metabolism between FFA and TG CLA diets. Rats (n=36) were fed a control (CTRL) or 1% CLA diet in FFA or TG form (1:1 mixture c9, t11: t10, c12). Liver content of c9, t11 CLA from FFA was greater than TG form and CTRL (FFA: 0.05±0.01 vs. TG: 0.02±0.01 vs. CTRL: 0.001±0.001% total fatty acids, P<0.0001). Liver t10, c12 CLA did not differ among groups (P=0.11). No diet differences among groups for growth, bone biomarkers or mass nor mineral balance were found. These findings suggest that c9, t11 CLA in FFA form is preferentially incorporated in the liver but fatty acid forms of CLA do not affect bone or mineral outcomes.

Variations in conjugated linoleic acid (CLA) content of processed cheese by lactation time, feeding regimen, and ripening

Dairy products are major sources of conjugated linoleic acid (CLA); thus, an increase in CLA content can improve the quality value of dairy products. The objective of this work was to determine the effects of lactation time, feeding regimen, and ripening period on the level of CLA in processed cheese. CLA content in milk varied with the period of lactation; high in spring (April and May, about 6.8 mg CLA/g fat) and relatively low in mid summer and winter (about 4.3 mg CLA/g fat). The effects of dietary regimen and ripening period were determined in milk, which was obtained from March to May. After aging for 4 months, the cheese made from milk obtained from cows fed on pasture contained relatively higher levels of CLA compared to cheese made from milk obtained from cows fed indoors (8.12 mg CLA/g fat vs 6.76 mg CLA/g fat), but there was no difference in 7 month-aged cheeses. In both pasture and indoor feeding, 7 month-aged cheeses showed higher CLA content than 4 month-aged cheeses. The contents of stearic acid (C18:0) and linolenic acid (C18:3) were significantly higher in cheese from pasture fed cows compared to those in cows fed indoors. These findings should be helpful for the efficient production of functional dairy products with high CLA contents.

Dietary fat concentration influences the effects of trans-10, cis-12 conjugated linoleic acid on temporal patterns of energy intake and hypothalamic expression of appetite-controlling genes in mice

This study tested the hypothesis that the effect of trans-10, cis-12 conjugated linoleic acid (t10, c12 CLA) on energy intake (EI) and body weight (BW)/composition is confounded by dietary fat concentration and involves hypothalamic appetite-controlling mechanisms. ICR mice received low-fat (LF; 5 g/100 g) or high-fat (HF; 30 g/100 g) diets, with or without 0.5 g/100 g t10, c12 CLA (>98% pure) for 27 d. By d 13, BW and cumulative EI of the mice fed CLA supplemented LF diet (LF/CLA) were 6.6 and 23.6% lower, respectively, than the LF mice. In the subsequent 14 d, their EI rebounded and did not differ from the LF group. BW and EI did not differ between the HF and CLA supplemented HF (HF/CLA) groups. Hypothalamic pro-opiomelanocortin (POMC) mRNA expression was elevated (P = 0.031) on d 13 but suppressed (P < 0.001) on d 27 due to CLA treatment. CLA also suppressed AMP-activated protein kinase alpha2 expression. Mice in Expt. 2 received the LF diet, the LF/CLA, or were pair-fed the LF diet to the EI of the CLA group (LF/PF). LF/CLA and LF/PF mice did not differ in the hypothalamic POMC:neuropeptide Y expression ratio on d 13, but it was significantly lower in the LF/PF group on d 27. We conclude that the habitual dietary fat concentration influences the magnitude of weight loss induced by dietary t10, c12 CLA. The effect is in part independent of EI. Hypothalamic neuropeptides and nutrient sensing mechanisms may play a role.

Immunological and metabolic effects of cis-9, trans-11-conjugated linoleic acid in subjects with birch pollen allergy

Animal studies suggest that conjugated linoleic acid (CLA) may modulate the immune response, while studies in healthy human subjects have shown little effect and results are controversial. However, the effects of CLA may be more prominent in situations of immune imbalance, such as allergy. We studied the effects of the natural CLA isomer, cis-9, trans-11-CLA, on allergy symptoms and immunological parameters in subjects with birch pollen allergy. In a randomised, placebo-controlled study, forty subjects (20-46 years) with diagnosed birch pollen allergy received 2 g CLA/d in capsules, which contained 65.3 % cis-9, trans-11-CLA and 8.5 % trans-10, cis-12-CLA (n 20), or placebo (high-oleic acid sunflower-seed oil) (n 20) for 12 weeks. The supplementation began 8 weeks before the birch pollen season and continued throughout the season. Allergy symptoms and use of medication were recorded daily. Lymphocyte subsets, cytokine production, immunoglobulins, C-reactive protein, lipid and glucose metabolism and lipid peroxidation were assessed before and after supplementation. The CLA group reported a better overall feeling of wellbeing (P < 0.05) and less sneezing (P < 0.05) during the pollen season. CLA supplementation decreased the in vitro production of TNF-alpha (P < 0.01), interferon-gamma (P < 0.05) and IL-5 (P < 0.05). Total plasma IgE and birch-specific IgE concentrations did not differ between groups, whereas plasma IgA (P < 0.05), granulocyte macrophage colony-stimulating factor (P < 0.05) and eosinophil-derived neurotoxin (P < 0.05) concentrations were lower after CLA supplementation. Urinary excretion of 8-iso-PGF2alpha, a major F2-isoprostane (P < 0.01), and 15-keto-dihydro-PGF2alpha, a primary PGF2alpha metabolite (P < 0.05), increased in the CLA group. The results suggest that cis-9, trans-11-CLA has modest anti-inflammatory effects in allergic subjects.

The promise of cytokine antibody arrays in the drug discovery process

The introduction of cytokine antibody arrays has added a new approach for investigators to simultaneously measure multiple cytokine levels in biological samples. Several different platforms have been developed. The ability to measure hundreds of cytokine levels with high specificity and sensitivity within a very limited amount of samples is a powerful tool. Many investigators worldwide have applied this novel technology in their biomedical research, particularly in drug discovery. Undoubtedly, the technology will continue to be improved and the application increased in the next several years.

Dietary effect of pomegranate seed oil on immune function and lipid metabolism in mice

OBJECTIVES

We evaluated the effects of dietary pomegranate seed oil (PSO), which contains high levels of punicic acid (9c, 11t, 13c-octadecatrienoic acid), on immune function and lipid metabolism in C57BL/6N mice.

METHODS

Mice were fed experimental diets containing 0%, 0.12%, or 1.2% PSO for 3 wk.

RESULTS

No significant differences were observed between growth patterns of the experimental groups. Splenocytes isolated from mice fed 0.12% or 1.2% PSO produced larger amounts of immunoglobulins G and M but not immunoglobulin A irrespective of stimulation with or without phorbol 12-myristate 13-acetate and the calcium ionophore A23187. Dietary PSO did not affect the percentages of B cells or CD4-positive or CD8-positive T cells in splenocytes. Levels of interleukin-4, interferon-gamma, and tumor necrosis factor-alpha production from splenocytes were comparable among all dietary groups. Analysis of serum lipid parameters showed significant increases in serum triacylglycerol and phospholipid levels but not in total cholesterol in the PSO groups. Serum, liver, epididymal, and perirenal adipose punicic acid levels were high with increases in dietary PSO level. However, punicic acid was not detected in splenocytes for any dietary group. Interestingly, 9c, 11t-conjugated linoleic acid level could be detected in serum, liver, and adipose tissues in mice fed the 0.12% or 1.2% PSO diet.

CONCLUSIONS

These results suggest that PSO may enhance B-cell function in vivo.