title: Vaccenic acid favourably alters immune function in obese JCR:LA-cp rats.
abstract: Vaccenic acid (VA) is a ruminant-derived trans-fat and precursor of conjugated linoleic acid (CLA). The objective of the present study was to explore the effects of VA on immune function in a model of the metabolic syndrome, JCR:LA-cp rats. Lean (2:1 mix of +/cp and +/+) and obese (cp/cp) rats, aged 8 weeks, were fed a control (0% VA) or a VA diet (1.5% (w/w) VA) for 3 weeks (twenty rats per group). Splenocytes and mesenteric lymph node (MLN) immune cell phenotypes (flow cytometry), ex vivo cytokine production (ELISA) and phospholipid fatty acid concentrations were measured. Obese rats had higher proportions of splenic macrophages, total T-cells, helper T-cells (total and percentage CD25+), cytotoxic T-cells (total and percentage CD25+) and produced higher concentrations of IL-6 to concanavalin A (ConA) compared with lean rats. Obese rats had lower proportions of MLN T-cells, new T-cells (CD3+CD90+) and cytotoxic T-cells, but higher proportions of helper cells that were CD45RC+, CD25+ and CD4lo, and produced higher concentrations of IL-2, IL-10, interferon gamma and TNFalpha in response to ConA compared with lean rats. VA was higher in plasma phospholipids and both VA and CLA (cis-9, trans-11) were higher in MLN phospholipids compared with control-fed rats. Lean VA-fed rats had lower proportions of MLN and splenocyte CD45RC+ helper cells, and helper T-cells. Splenocytes from VA-fed rats produced 16-23% less IL-2, IL-10 and TNFalpha compared with controls. VA normalised production of MLN IL-2 and TNFalpha in obese rats to levels similar to those seen in lean rats. These results indicate that dietary VA favourably alters the pro-inflammatory tendency of mesenteric lymphocytes from JCR:LA-cp rats.
authors.affiliation: Alberta Institute for Human Nutrition, Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Blewett
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Gerdung
authors.forename: Megan R
authors.initials: MR
authors.lastname: Ruth
authors.forename: Spencer D
authors.initials: SD
authors.lastname: Proctor
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Field
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D016207:Cytokines / Q000276:immunology; D004032:Diet; D005227:Fatty Acids / Q000032:analysis; D016130:Immunophenotyping; D007962:Leukocytes / Q000276:immunology*; D008198:Lymph Nodes / Q000737:chemistry; D018655:Lymphocyte Count; D008297:Male; D024821:Metabolic Syndrome / Q000276:immunology*; D023421:Models, Animal; D009765:Obesity / Q000276:immunology*; D009829:Oleic Acids / Q000008:administration & dosage*; D011897:Random Allocation; D051381:Rats; D011922:Rats, Mutant Strains; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D016207:Cytokines; D005227:Fatty Acids; D009829:Oleic Acids; C050413:11-octadecenoic acid