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Crit Care. 2010;14(1):R16. doi: 10.1186/cc8873. Epub 2010 Feb 11.

Cerebral net exchange of large neutral amino acids after lipopolysaccharide infusion in healthy humans.

Author information

1
Centre of Inflammation and Metabolism, Department of Infectious Diseases, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark. ronan@dadlnet.dk

Abstract

INTRODUCTION:

Alterations in circulating large neutral amino acids (LNAAs), leading to a decrease in the plasma ratio between branched-chain and aromatic amino acids (BCAA/AAA ratio), may be involved in sepsis-associated encephalopathy. We hypothesised that a decrease in the BCAA/AAA ratio occurs along with a net cerebral influx of the neurotoxic AAA phenylalanine in a human experimental model of systemic inflammation.

METHODS:

The BCAA/AAA ratio, the cerebral delivery, and net exchange of LNAAs and ammonia were measured before and 1 hour after a 4-hour intravenous infusion of Escherichia coli lipopolysaccharide (LPS) in 12 healthy young men.

RESULTS:

LPS induced systemic inflammation, reduced the BCAA/AAA ratio, increased the cerebral delivery and unidirectional influx of phenylalanine, and abolished the net cerebral influx of the BCAAs leucine and isoleucine. Furthermore, a net cerebral efflux of glutamine, which was independent of the cerebral net exchange of ammonia, was present after LPS infusion.

CONCLUSIONS:

Systemic inflammation may affect brain function by reducing the BCAA/AAA ratio, thereby changing the cerebral net exchange of LNAAs.

PMID:
20149231
PMCID:
PMC2875531
DOI:
10.1186/cc8873
[Indexed for MEDLINE]
Free PMC Article

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