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Leukocyte numbers and function in subjects eating n-3 enriched foods: selective depression of natural killer cell levels.

Mukaro VR, Costabile M, Murphy KJ, Hii CS, Howe PR, Ferrante A - Arthritis Res. Ther. (2008)

Bottom Line: No significant correlations were found with respect to lymphocyte lymphoproliferation and production of IFN-gamma and IL-2, but lymphotoxin production was higher with greater n-3 LCPUFA membrane content.Similarly, neutrophil chemotaxis, chemokinesis, bactericidal activity and adherence did not vary with changes in erythrocyte n-3 LCPUFA levels, but the iodination reaction was reduced with higher n-3 LCPUFA content.The data show that regular long-term consumption of n-3 enriched foods leads to lower numbers of NK cells and neutrophil iodination activity but higher lymphotoxin production by lymphocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Immunopathology, Children, Youth and Women's Health Service, 72 King William Road, North Adelaide SA 5006, Australia.

ABSTRACT

Introduction: While consumption of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) has been recommended for those at risk of inflammatory disease such as rheumatoid arthritis, the mechanism of their anti-inflammatory effect remains to be clearly defined, particularly in relation to the dose and type of n-3 LCPUFA. The objective of this study was to determine whether varying the levels of n-3 LCPUFA in erythrocyte membrane lipids, following dietary supplementation, is associated with altered numbers and function of circulating leukocytes conducive to protection against inflammation.

Methods: In a double-blind and placebo-controlled study, 44 healthy subjects aged 23 to 63 years consumed either standard or n-3 LCPUFA-enriched versions of typical processed foods, the latter allowing a target daily consumption of 1 gram n-3 LCPUFA. After six months, peripheral blood leukocyte and subpopulation proportions and numbers were assessed by flow cytometry. Leukocytes were also examined for lymphoproliferation and cytokine production, neutrophil chemotaxis, chemokinesis, bactericidal, adherence and iodination activity. Erythrocytes were analyzed for fatty-acid content.

Results: Erythrocyte n-3 LCPUFA levels were higher and absolute leukocyte and lymphocyte numbers were lower in subjects consuming n-3 enriched foods than in controls. There were no changes in the number of neutrophils, monocytes, T cells (CD3+), T-cell subsets (CD4+, CD8+) and B cells (CD19+). However, natural killer (NK) (CD3-CD16+CD56+) cell numbers were lower in n-3 supplemented subjects than in controls and were inversely related to the amount of eicosapentaenoic acid or docosahexaenoic acid in erythrocytes. No significant correlations were found with respect to lymphocyte lymphoproliferation and production of IFN-gamma and IL-2, but lymphotoxin production was higher with greater n-3 LCPUFA membrane content. Similarly, neutrophil chemotaxis, chemokinesis, bactericidal activity and adherence did not vary with changes in erythrocyte n-3 LCPUFA levels, but the iodination reaction was reduced with higher n-3 LCPUFA content.

Conclusion: The data show that regular long-term consumption of n-3 enriched foods leads to lower numbers of NK cells and neutrophil iodination activity but higher lymphotoxin production by lymphocytes. These changes are consistent with decreased inflammatory reaction and tissue damage seen in patients with inflammatory disorders receiving n-3 LCPUFA supplementation.

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Levels of n-3 fatty acids in membrane phospholipids of erythrocytes. (a) Eicosapentaeonic acid (EPA), (b) docosahexaenoic aid (DHA) and (c) n-3 LCPUFA (EPA + docosapentaenoic acid (DPA) + DHA) in the placebo and supplemented groups. Blood was taken after 6 months and analyzed for fatty-acid composition as outlined in Materials and methods. Data are expressed as mean ± SEM; n = 18 for the placebo group and n = 20 for the supplemented group. ***p < 0.0001, Student t-test.
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Figure 1: Levels of n-3 fatty acids in membrane phospholipids of erythrocytes. (a) Eicosapentaeonic acid (EPA), (b) docosahexaenoic aid (DHA) and (c) n-3 LCPUFA (EPA + docosapentaenoic acid (DPA) + DHA) in the placebo and supplemented groups. Blood was taken after 6 months and analyzed for fatty-acid composition as outlined in Materials and methods. Data are expressed as mean ± SEM; n = 18 for the placebo group and n = 20 for the supplemented group. ***p < 0.0001, Student t-test.

Mentions: A total of 42 (21 placebo and 21 supplemented) individuals completed the study; however, a few samples were not viable and/or were lost, thus accounting for the variation in sample numbers. Analysis of the erythrocyte membrane lipid composition (n = 18 placebo and n = 20 n-3 LCPUFA supplemented) showed considerable overlap in levels of n-3 and n-6 PUFA, EPA and DHA between the two groups (Figure 1). The EPA, DHA and total n-3 LCPUFA (docosapentaenoic acid (DPA) + EPA + DHA) content in the enriched group was significantly higher than in the placebo group (Figure 1), whereas the total n-6 LCPUFA content was higher in the placebo group than in the supplemented groups (data not shown) 24.8 ± 0.23 % and 22.65 ± 0.31% respectively (p < 0.0001).


Leukocyte numbers and function in subjects eating n-3 enriched foods: selective depression of natural killer cell levels.

Mukaro VR, Costabile M, Murphy KJ, Hii CS, Howe PR, Ferrante A - Arthritis Res. Ther. (2008)

Levels of n-3 fatty acids in membrane phospholipids of erythrocytes. (a) Eicosapentaeonic acid (EPA), (b) docosahexaenoic aid (DHA) and (c) n-3 LCPUFA (EPA + docosapentaenoic acid (DPA) + DHA) in the placebo and supplemented groups. Blood was taken after 6 months and analyzed for fatty-acid composition as outlined in Materials and methods. Data are expressed as mean ± SEM; n = 18 for the placebo group and n = 20 for the supplemented group. ***p < 0.0001, Student t-test.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2483446&req=5

Figure 1: Levels of n-3 fatty acids in membrane phospholipids of erythrocytes. (a) Eicosapentaeonic acid (EPA), (b) docosahexaenoic aid (DHA) and (c) n-3 LCPUFA (EPA + docosapentaenoic acid (DPA) + DHA) in the placebo and supplemented groups. Blood was taken after 6 months and analyzed for fatty-acid composition as outlined in Materials and methods. Data are expressed as mean ± SEM; n = 18 for the placebo group and n = 20 for the supplemented group. ***p < 0.0001, Student t-test.
Mentions: A total of 42 (21 placebo and 21 supplemented) individuals completed the study; however, a few samples were not viable and/or were lost, thus accounting for the variation in sample numbers. Analysis of the erythrocyte membrane lipid composition (n = 18 placebo and n = 20 n-3 LCPUFA supplemented) showed considerable overlap in levels of n-3 and n-6 PUFA, EPA and DHA between the two groups (Figure 1). The EPA, DHA and total n-3 LCPUFA (docosapentaenoic acid (DPA) + EPA + DHA) content in the enriched group was significantly higher than in the placebo group (Figure 1), whereas the total n-6 LCPUFA content was higher in the placebo group than in the supplemented groups (data not shown) 24.8 ± 0.23 % and 22.65 ± 0.31% respectively (p < 0.0001).

Bottom Line: No significant correlations were found with respect to lymphocyte lymphoproliferation and production of IFN-gamma and IL-2, but lymphotoxin production was higher with greater n-3 LCPUFA membrane content.Similarly, neutrophil chemotaxis, chemokinesis, bactericidal activity and adherence did not vary with changes in erythrocyte n-3 LCPUFA levels, but the iodination reaction was reduced with higher n-3 LCPUFA content.The data show that regular long-term consumption of n-3 enriched foods leads to lower numbers of NK cells and neutrophil iodination activity but higher lymphotoxin production by lymphocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Immunopathology, Children, Youth and Women's Health Service, 72 King William Road, North Adelaide SA 5006, Australia.

ABSTRACT

Introduction: While consumption of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) has been recommended for those at risk of inflammatory disease such as rheumatoid arthritis, the mechanism of their anti-inflammatory effect remains to be clearly defined, particularly in relation to the dose and type of n-3 LCPUFA. The objective of this study was to determine whether varying the levels of n-3 LCPUFA in erythrocyte membrane lipids, following dietary supplementation, is associated with altered numbers and function of circulating leukocytes conducive to protection against inflammation.

Methods: In a double-blind and placebo-controlled study, 44 healthy subjects aged 23 to 63 years consumed either standard or n-3 LCPUFA-enriched versions of typical processed foods, the latter allowing a target daily consumption of 1 gram n-3 LCPUFA. After six months, peripheral blood leukocyte and subpopulation proportions and numbers were assessed by flow cytometry. Leukocytes were also examined for lymphoproliferation and cytokine production, neutrophil chemotaxis, chemokinesis, bactericidal, adherence and iodination activity. Erythrocytes were analyzed for fatty-acid content.

Results: Erythrocyte n-3 LCPUFA levels were higher and absolute leukocyte and lymphocyte numbers were lower in subjects consuming n-3 enriched foods than in controls. There were no changes in the number of neutrophils, monocytes, T cells (CD3+), T-cell subsets (CD4+, CD8+) and B cells (CD19+). However, natural killer (NK) (CD3-CD16+CD56+) cell numbers were lower in n-3 supplemented subjects than in controls and were inversely related to the amount of eicosapentaenoic acid or docosahexaenoic acid in erythrocytes. No significant correlations were found with respect to lymphocyte lymphoproliferation and production of IFN-gamma and IL-2, but lymphotoxin production was higher with greater n-3 LCPUFA membrane content. Similarly, neutrophil chemotaxis, chemokinesis, bactericidal activity and adherence did not vary with changes in erythrocyte n-3 LCPUFA levels, but the iodination reaction was reduced with higher n-3 LCPUFA content.

Conclusion: The data show that regular long-term consumption of n-3 enriched foods leads to lower numbers of NK cells and neutrophil iodination activity but higher lymphotoxin production by lymphocytes. These changes are consistent with decreased inflammatory reaction and tissue damage seen in patients with inflammatory disorders receiving n-3 LCPUFA supplementation.

Show MeSH
Related in: MedlinePlus