Total parenteral nutrition directly impairs cytokine production after bacterial challenge.
OBJECTIVE
Previous studies have shown that total parenteral nutrition (TPN) influences host immunity, but the mechanism is unclear. This study explored the effect of TPN solution on neutrophil phagocytosis and whole-blood cytokine production in response to coagulase-negative staphylococci in vitro challenge.


METHODS
Blood samples were taken from five enterally fed infants (age <6 months) and six healthy adults. Samples were incubated for 45 minutes with four isovolemic solutions: (A) control (saline), (B) TPN (0.1 microL/mL of blood), (C) TPN (1 microL/mL), (D) TPN (10 microL/mL). Solution C (1 microL/mL) corresponded to TPN-blood ratio used in clinical practice. After incubation, blood was challenged with coagulase-negative staphylococci. Neutrophil phagocytosis was measured by flow cytometry after 40 minutes of bacterial challenge, and tumour necrosis factor alpha (TNF-alpha) was measured by enzyme-linked immunosorbent assay (ELISA) after 2 hours of bacterial challenge.


RESULTS
In infant blood, TNF-alpha production after coagulase-negative staphylococci challenge was impaired after the addition of a "physiological" dose of TPN solution (1 microL/mL of blood) as well as "supranormal" doses (10 microL/mL of blood). In adult blood, a similar effect was observed only after the addition of a supranormal dose of TPN. In both the infant and adult blood, there was no direct effect of TPN solution on neutrophil phagocytosis.


CONCLUSIONS
These results suggest that infants are more susceptible than adults to TPN-related depression of cytokine production. The level of proinflammatory cytokines may be important in the host defence against bacterial infection.
Paediatric Surgery Unit, Institute of Child Health and Great Ormond Street Hospital for Children, University College London Medical School, England.
Y
Y
Okada
E
E
Papp
N J
NJ
Klein
A
A
Pierro
D000328:Adult; D001770:Blood Bactericidal Activity / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007223:Infant; D009504:Neutrophils / Q000276:immunology; D010289:Parenteral Nutrition, Total / Q000009:adverse effects*; D010587:Phagocytosis / Q000502:physiology; D013210:Staphylococcus / Q000276:immunology; D018709:Statistics, Nonparametric; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D014409:Tumor Necrosis Factor-alpha