Heikki Savolainen, Dept. of Occup. Safety & Hlth., Tampere, Finland
12 February 2010
Dear Editor,
This investigations shows that infusion of LPS may alter the brain uptake of amino acids. It is thought that this may be a contributing factor to the clinical encephalopathy analogously to effects of hyperammonemia (1).
One wonders whether this is due to an effect on the amino acid transporter across the blood-brain barrier (2) or whether it reflects changes in the circulation due to increased NO.
The postulated contributory role of amino acids would be more convincing if glutamate or glycine uptake would be specifically affected.
1 James JH, Jeppson B, Ziparo V, et al. Hyperammonemia, plasma amino acid imblanace and blood-brain amino acid transport. A unified theory of portal systemic encephalopathy. Lancet 1979; ii: 772
2 Smith QR, Momma S, Aoyagi M, et al. Kinetics of neutral amino acid transport across the blood-brain barrier. J Neurochem 1987; 49: 603
Critical Care
Amino acid imbalance and encephalopathy
12 February 2010
Dear Editor,
This investigations shows that infusion of LPS may alter the brain uptake of amino acids. It is thought that this may be a contributing factor to the clinical encephalopathy analogously to effects of hyperammonemia (1).
One wonders whether this is due to an effect on the amino acid transporter across the blood-brain barrier (2) or whether it reflects changes in the circulation due to increased NO.
The postulated contributory role of amino acids would be more convincing if glutamate or glycine uptake would be specifically affected.
1 James JH, Jeppson B, Ziparo V, et al. Hyperammonemia, plasma amino acid imblanace and blood-brain amino acid transport. A unified theory of portal systemic encephalopathy. Lancet 1979; ii: 772
2 Smith QR, Momma S, Aoyagi M, et al. Kinetics of neutral amino acid transport across the blood-brain barrier. J Neurochem 1987; 49: 603
Competing interests
None