Phagocytosis and killing of Candida albicans by human neutrophils after exposure to structurally different lipid emulsions.
BACKGROUND
To test the hypothesis that structurally different lipid emulsions have distinct immune-modulating properties, we analyzed the elimination of Candida albicans by neutrophils after exposure to various emulsions.


METHODS
Neutrophils from 8 volunteers were incubated in physiologic 5 mmol/L emulsions containing long-chain- (LCT), medium-chain- (MCT), mixed LCT/MCT-, alpha-tocopherol-enriched LCT/MCT (LCT/MCT-E), or structured lipids (SL). After washing, the neutrophils were incubated with C. albicans. Phagocytosis was measured as the number of yeast-associated neutrophils relative to the total neutrophil count. Killing was expressed as the percentage of Candida survival relative to the initial yeast cell count.


RESULTS
No significant differences in yeast-neutrophil association could be demonstrated after neutrophil incubation in various lipid emulsions or medium, after correction for non-specific adhesion. However, although Candida survival after 1 hour incubation with non-lipid-exposed neutrophils amounted to 53% +/- 11% and was not influenced by LCT (60% +/- 11%), LCT/MCT (78% +/- 7%), LCT/MCT-E (72% +/- 12%), and SL (67% +/- 6%), pure MCT (70% +/- 13%) significantly impaired the killing capacity of neutrophils.


CONCLUSIONS
The decreased killing capacity of neutrophils after exposure to medium-chain fatty acid-containing emulsions and the absence of this effect with LCT suggest that lipid emulsions influence the elimination of C. albicans depending on the triglyceride chain length.
Wanten
G J
GJ
Department of Gastroenterology, University Medical Center St. Radboud, Nijmegen, The Netherlands.
Curfs
J H
JH
Meis
J F
JF
Naber
A H
AH
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000328:Adult; D002176:Candida albicans / Q000276:immunology* / Q000502:physiology; D002177:Candidiasis / Q000276:immunology / Q000382:microbiology; D015169:Colony Count, Microbial; D005217:Fat Emulsions, Intravenous / Q000494:pharmacology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D010587:Phagocytosis / Q000187:drug effects
D000276:Adjuvants, Immunologic; D005217:Fat Emulsions, Intravenous