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Aromatic amino acid metabolism during liver failure
Cornelis H C Dejong1, Marcel C G van de Poll, Peter B Soeters
1Department of Surgery, Nutrition and Toxicology Institute Maastricht, Maastricht University, the Netherlands. chc.dejong@ah.unimaas.nl
The Journal of Nutrition
|May 22, 2007
Summary
Imbalances in aromatic amino acids (AAA) and branched-chain amino acids (BCAA) are linked to hepatic encephalopathy (HE). While AAA levels correlate with liver function, HE likely results from multiple factors, not just amino acid imbalances.
Area of Science:
- Biochemistry
- Hepatology
- Neuroscience
Background:
- Hepatic encephalopathy (HE) is a complication of liver failure.
- Plasma amino acid imbalances, specifically aromatic amino acids (AAA) and branched-chain amino acids (BCAA), are implicated in HE pathogenesis.
- Limited human data existed due to challenges in accessing key blood vessels.
Purpose of the Study:
- To investigate the role of AAA and BCAA in HE using accessible venous samples.
- To examine amino acid profiles in patients undergoing liver resection and those with transjugular intrahepatic portasystemic shunt (TIPSS).
Main Methods:
- Analysis of plasma amino acid levels (AAA and BCAA) and their ratio in patients with liver conditions.
- Comparison of amino acid profiles in patients with liver resection and TIPSS versus healthy controls.
- Assessment of amino acid changes following gastrointestinal bleeding in cirrhotics with TIPSS.
Main Results:
- Plasma AAA levels inversely correlated with residual liver volume post-resection.
- Patients with cirrhosis and TIPSS exhibited a lower BCAA/AAA ratio compared to controls.
- Gastrointestinal bleeding in cirrhotics with TIPSS led to altered BCAA levels and ratio, responsive to isoleucine supplementation.
Conclusions:
- Amino acid imbalances, particularly AAA, are associated with liver function and potentially HE.
- HE pathogenesis is multifactorial, involving hyperammonemia, amino acid imbalances, inflammation, and neurotransmitter changes.
- Therapeutic strategies for HE may require combined approaches, including normalizing AAA levels, BCAA supplementation, and ammonia excretion enhancement.
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