Parenteral lipids impair pneumococcal elimination by human neutrophils

• Published in: European journal of clinical investigation 2010-08, Vol.40 (8), p.729-734
• Main Authors: Versleijen, Michelle W., Roelofs, Hennie M., Te Morsche, Rene H., Simonetti, Elles R., Hermans, Peter W., Wanten, Geert J.
• Format: Article
• Language: English
• Subjects: Adult; Bacterial diseases; Biological and medical sciences; Cells, Cultured; Colony Count, Microbial; Data processing; Female; Fish Oils; General aspects; Human; Human bacterial diseases; Humans; immune modulation; Immunoglobulins; Infection; Infectious diseases; Leukocytes (neutrophilic); Lipids; Lipids - pharmacology; Male; Medical sciences; neutrophil; Neutrophils - drug effects; Neutrophils - physiology; Oils; Opsonization; parenteral lipid; Parenteral nutrition; Phagocytes; Phagocytosis; Phagocytosis - drug effects; Plant Extracts; pneumococcal survival; Pneumonia; Staphylococcal infections, streptococcal infections, pneumococcal infections; Streptococcus pneumoniae; Streptococcus pneumoniae - physiology; Young Adult
• ISSN: 0014-2972; 1365-2362
• DOI: 10.1111/j.1365-2362.2010.02320.x

Eur J Clin Invest 2010; 40 (8): 729–734 Background  Lipid‐induced modulation of phagocyte function seems to contribute to increased susceptibility to infections in patients on parenteral nutrition, and an increased risk for development of pneumonia has been observed in this group. The role of various structurally different lipid emulsions, however, remains unclear. In this study, we therefore assessed phagocyte function, as the capacity of neutrophils to eliminate Streptococcus pneumoniae (i.e. combined result of phagocytosis and killing), in the presence of these lipids. Materials and methods  Neutrophils from six healthy volunteers were incubated for 1 h in emulsions (5 mmol L−1) derived from soybean‐ (LCT), fish‐ (VLCT), olive‐ (LCT‐MUFA), mixed soybean/coconut oils (LCT/MCTs) or structured lipids (SL). After opsonization of the pneumococci (strain OREP‐4) by human immunoglobulins, bacteria and neutrophils were incubated in the presence of complement. Next, pneumococcal elimination was evaluated and expressed as the percentage of bacteria eliminated relative to the initial bacterial numbers in neutrophil‐free samples. Results  Neutrophils that were not exposed to lipids showed a pneumococcal elimination capacity of 75 ± 3% (mean ± SD). This significantly decreased after exposure to LCT‐MUFA (70 ± 6%), VLCT (67 ± 2%), SL (63 ± 9%), LCT (66 ± 10%) and LCT/MCT (47 ± 15%). Conclusion  These data demonstrate that parenteral lipids impair the microbial elimination capacity of neutrophils in a structure‐dependent manner. In accordance with our previously reported in vitro effect on a range of phagocyte functions, LCT/MCT is by far the most potent in this respect.