The effect of different sources of fish and camelina sativa oil on immune cell and adipose tissue mRNA expression in subjects with abnormal fasting glucose metabolism: a randomized controlled trial

Vanessa D De Mello,Sudhir Kurl,Ursula S Schwab,Maria Lankinen,Leena Pitkänen,David E Laaksonen,Arja T Erkkilä,Ingrid Dahlman

doi:10.1038/s41387-018-0069-2

Abstract

Background/ObjectivesMolecular mechanisms linking fish and vegetable oil intakes to their healthy metabolic effects may involve attenuation of inflammation. Our primary aim was to examine in a randomized controlled setting whether diets enriched in fatty fish (FF), lean fish (LF) or ALA-rich camelina sativa oil (CSO) differ in their effects on the mRNA expression response of selected inflammation-related genes in peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissue (SAT) in subjects with impaired fasting glucose.Subjects/MethodsSamples from 72 participants randomized to one of the following 12-week intervention groups, FF (n = 19), LF (n = 19), CSO (n = 17) or a control group (n = 17), were available for the PBMC study. For SAT, 39 samples (n = 8, n = 10, n = 9, n = 12, respectively) were available. The mRNA expression was measured at baseline and 12 weeks by TaqMan® Low Density Array.ResultsIn PBMCs, LF decreased ICAM1 mRNA expression (P < 0.05), which was different (P = 0.06, Bonferroni correction) from the observed increase in the FF group (P < 0.05). Also, compared to the control group, LF decreased ICAM1 mRNA expression (P < 0.05). Moreover, the change in ICAM1 mRNA expression correlated positively with the intake of FF (P < 0.05) and negatively with the intake of LF (P < 0.05), independently of study group. A diet enriched in CSO, a rich source of alpha-linolenic acid (ALA), decreased PBMC IFNG mRNA expression (P < 0.01). The intake of CSO in the CSO group, but not the increase in plasma ALA proportions, correlated inversely with the IFNG mRNA expression in PBMCs (P = 0.08). In SAT, when compared with the control group, the effect of FF on decreasing IL1RN mRNA expression was significant (P < 0.03).ConclusionWe propose that CSO intake may partly exert its benefits through immuno-inflammatory molecular regulation in PBMCs, while modulation of ICAM1 expression, an endothelial/vascular-related gene, may be more dependent on the type of fish consumed.

Highlights

Dietary sources of n-3 fatty acids (FAs), e.g., fish as a source of eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic (DHA, 22:6 n-3) and vegetable oils richNutrition and Diabetes de Mello et al Nutrition and Diabetes (2019)9:1 in alpha-linolenic acid (ALA, 18:3 n-3), are regarded to have beneficial effects on serum lipid profile and glucose metabolism, even though still controversial[1,2,3,4], potentially contributing to a protective effect against type 2 diabetes (T2D) and cardiovascular disease (CVD)
A diet enriched in camelina sativa oil (CSO), a rich source of alpha-linolenic acid (ALA), decreased peripheral blood mononuclear cells (PBMCs) IFNG messenger RNA (mRNA) expression (P < 0.01)
We propose that CSO intake may partly exert its benefits through immuno-inflammatory molecular regulation in PBMCs, while modulation of ICAM1 expression, an endothelial/vascular-related gene, may be more dependent on the type of fish consumed

Summary

Introduction

Dietary sources of n-3 fatty acids (FAs), e.g., fish as a source of eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic (DHA, 22:6 n-3) and vegetable oils richNutrition and Diabetes de Mello et al Nutrition and Diabetes (2019)9:1 in alpha-linolenic acid (ALA, 18:3 n-3), are regarded to have beneficial effects on serum lipid profile and glucose metabolism, even though still controversial[1,2,3,4], potentially contributing to a protective effect against type 2 diabetes (T2D) and cardiovascular disease (CVD). Dietary sources of n-3 fatty acids (FAs), e.g., fish as a source of eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic (DHA, 22:6 n-3) and vegetable oils rich. One of the possible mechanisms linking the protective effect of n-3 FAs could be through decreasing inflammation. Previous results have shown that different sources of n-3 FAs, mainly EPA and DHA, may affect gene expression levels of markers involved in inflammation and immune system[10,11,12]. Even though we and others have found conflicting results in the effect of n-3 FAs or LF on the expression of immune-inflammatory related genes, these studies were performed in different populations and lacked an intervention arm with dietary n-3 FA content as vegetable oil or fat[1,13,14]

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