Related Experiment Video
Updated: Jul 30, 2026
Quantitative In vitro Assay to Measure Neutrophil Adhesion to Activated Primary Human Microvascular Endothelial Cells under Static Conditions
Published on: August 23, 2013
Differential neutrophil activation before and after endotoxin infusion in enterally versus parenterally fed
1Department of Surgery, Cornell University Medical College, New York, New York.
Abstract:
This study was done to determine whether or not increased susceptibility to infection seen in enterally versus parenterally fed patients was caused by altered neutrophil (PMN) responsiveness. To determine the differential effects of route of feeding on human PMN activation, plasma C3a levels, circulating PMN counts, PMN migration to leukotriene B4 (LTB4), the peptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP) and zymosan activated serum (ZAS) and generation of LTB4 were assayed before and after and infusion of endotoxin. Nine normal volunteers were enterally (n=4) or parenterally (n=5) fed a diet sufficient to maintain body weight for seven days prior to a standard challenge of endotoxin. Samples were taken prior to the infusion and hourly thereafter for six hours. Prior to the injection of endotoxin, significant differences were seen in the two feeding groups. Plasma C3a levels, absolute circulating PMN counts and chemotaxis to LTB4 were all significantly (p less than 0.02) elevated in the enterally fed group. Generation of LTB4 was higher in the intravenously fed group at base line than the orally fed group (p less than 0.05). Plasma C3a levels rose in the enterally fed group, but not in the intravenously fed group, at two hours after infusion. Neutrophil counts rose in both feeding groups after endotoxin infusion; but the change in percentage was greater in the enterally fed group than in the intravenously fed group. Chemotaxis to FMLP and ZAS was not different during the study and did not differ between the two feeding can have significant impact on neutrophil function and that parenteral nutrition may impair host responsiveness.
Insights
Enteral nutrition enhances neutrophil function, unlike parenteral nutrition, which may impair immune response. This study investigated how feeding routes affect neutrophil responsiveness and infection susceptibility in patients.
Area of Science:
- Immunology
- Nutrition Science
- Gastroenterology
Background:
- Increased infection susceptibility is observed in enterally versus parenterally fed patients.
- Neutrophil (PMN) responsiveness is a key factor in host defense against infection.
Purpose of the Study:
- To determine if altered neutrophil responsiveness explains increased infection susceptibility in enterally fed patients.
- To investigate the differential effects of enteral versus parenteral nutrition on human neutrophil activation and function.
Main Methods:
- Assayed plasma C3a levels, circulating PMN counts, PMN migration (chemotaxis), and leukotriene B4 (LTB4) generation.
- Measured these parameters before and after endotoxin infusion in normal volunteers receiving either enteral or parenteral nutrition for seven days.
- Utilized chemotaxis assays with LTB4, N-formyl-methionyl-leucyl-phenylalanine (FMLP), and zymosan activated serum (ZAS).
Main Results:
- Prior to endotoxin, enterally fed group showed elevated plasma C3a, circulating PMN counts, and LTB4 chemotaxis (p < 0.02).
- Baseline LTB4 generation was higher in parenterally fed individuals (p < 0.05).
- Post-endotoxin, neutrophil counts increased more significantly in the enterally fed group; plasma C3a rose in enterally fed but not parenterally fed individuals.
Conclusions:
- Route of feeding significantly impacts neutrophil function.
- Parenteral nutrition may impair host immune responsiveness compared to enteral nutrition.
- Altered neutrophil responsiveness could contribute to differential infection susceptibility based on feeding route.
