Influence of weight reduction on blood levels of C-reactive protein, tumor necrosis factor-α, interleukin-6, and oxylipins in obese subjects

authored by

Katharina Möller, Annika I Ostermann, Katharina Rund, Stefanie Thoms, Cornelia Blume, Frank Stahl, Andreas Hahn, Nils Helge Schebb, Jan Philipp Schuchardt

Abstract

Introduction: Obesity is associated with inflammation and weight reduction has been shown to influence the inflammatory process. Besides classic inflammatory markers, oxidized polyunsaturated fatty acid (PUFA) metabolites (oxylipins) are potent mediators of inflammation. Little is known about endogenous levels of oxylipins, e.g. hydroxy, epoxy and dihydroxy FA in obese subjects with persistent low-grade inflammation. We aimed to evaluate levels of inflammatory markers and blood oxylipins in obese subjects before and after weight reduction. Subjects and methods: In the present study, 42 obese (BMI 32.7±0.22 kg/m

²) men and women were classified in groups according to high-sensitivity C-reactive protein (hsCRP) levels (no inflammation<1 mg/L; low-grade inflammation≥3 mg/L). Subjects underwent an intervention for eight weeks, which consisted of two phases: (1) week 1 and 2: total replacement of three meals by a formula diet and (2) six week partial formula diet (replacement of 1-2 meals). Blood samples were taken prior and post intervention for analysis of plasma protein levels of hsCRP, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Plasma Levels of free (unesterified) hydroxy, epoxy, and dihydroxy FAs as well as several prostanoids were analyzed in plasma by means of LC-MS-based targeted metabolomics. Results: At baseline subjects with low-grade inflammation (hsCRP 8.95±1.39 mg/L) showed significant higher levels of IL-6 (22.7±1.15 ng/L) and TNF-α (17.4±0.75 ng/L) compared to subjects with no inflammation (hsCRP: 0.69±0.05 mg/L; IL-6: 15.9±1.18 ng/L; TNF-α: 14.6±0.80 ng/L). In both group's body weight was significantly reduced (p<0.001) after intervention (no inflammation group: -7.19±0.86 kg, -7.3±0.89%, p<0.001; low-grade inflammation group: -6.78±0.87 kg, -6.7±0.81%, p<0.001). Moreover, we observed significant decreases in levels of hsCRP (4.66±0.64 mg/L; p=0.006), IL-6 (6.81±1.15 ng/L; p<0.001) and TNF-α (6.09±0.47 ng/L; p<0.001) in subjects with low-grade inflammation. Of 60 quantified oxylipins, 11 linoleic acid (LA)-, 1 dihomo-γ-linolenic acid (DGLA)-, 7 alpha linolenic acid (ALA)-, 15 arachidonic acid (AA)-, 8 eicosapentaenoic acid (EPA)- and 18 docosahexaenoic acid (DHA)-metabolites could be detected in plasma. For most oxylipins no differences were found between the low and high hsCRP groups before and after weight reduction. Interestingly, in subjects with low- grade inflammation several AA-derived oxylipins (5-, 8-, 12-hydroxyeicosatetraenoic acids (HETE)) were significantly higher compared to subjects with no inflammation before weight reduction and significantly reduced after weight reduction. Conclusion: Even moderate weight loss in obese subjects correlates to a significant improvement in the inflammatory state, by reducing hsCRP, IL-6, TNF-α and few oxylipins. The biological consequences of these changes remain to be further investigated.

Organisation(s)

Institute of Food Science and Human Nutrition
Institute of Technical Chemistry
Nutrition Physiology and Human Nutrition Section

External Organisation(s)

University of Veterinary Medicine of Hannover, Foundation
The University of Wuppertal

Type

Article

Journal

Prostaglandins Leukotrienes and Essential Fatty Acids

Volume

106

Pages

39-49

No. of pages

ISSN

0952-3278

Publication date

01.03.2016

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Clinical Biochemistry, Cell Biology

Sustainable Development Goals

SDG 3 - Good Health and Well-being

Electronic version(s)

https://doi.org/10.1016/j.plefa.2015.12.001 (Access: Closed)