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Updated: May 13, 2026
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Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
Published on: February 16, 2018
Ornithine phenylacetate revisited.
Maria Jover-Cobos1, Lorette Noiret, Yalda Sharifi
1Liver Failure Group, UCL Institute for Liver and Digestive Health, The Royal Free Hospital, University College London, Pond Street, London NW3 2PF, UK. m.cobos@ucl.ac.uk
Metabolic Brain Disease
|March 5, 2013
Summary
Ornithine phenylacetate (OP) effectively reduces ammonia levels in liver failure patients, potentially treating hepatic encephalopathy (HE). This novel drug shows promise for improving brain function and immune status in liver disease.
Area of Science:
- Hepatology
- Pharmacology
- Biochemistry
Background:
- Hyperammonemia in liver failure contributes to hepatic encephalopathy (HE) and immune dysfunction.
- Effective treatments for hyperammonemia remain an unmet clinical need.
- Ornithine phenylacetate (OP) is a potential therapeutic agent for hyperammonemia in liver disease.
Purpose of the Study:
- To review the mechanism of action of OP.
- To evaluate OP's effects on plasma ammonia, brain function, and inflammation in acute and chronic liver failure.
- To assess OP's safety and efficacy in treating HE.
Main Methods:
- Review of existing literature on OP's mechanism and effects.
- Analysis of studies in animal models (rodents, pigs) and human trials.
- Examination of OP's impact on ammonia metabolism, brain edema, and intracranial pressure.
Main Results:
- OP reduces plasma ammonia levels for extended periods in animal models and humans.
- Ammonia reduction is achieved by stimulating glutamine synthesis, direct excretion of phenylacetylglutamine, and normalizing gut glutaminase activity.
- OP administration reduced brain edema in rats and intracranial hypertension in pigs.
- OP has demonstrated safety in human studies, with trials for overt HE ongoing.
Conclusions:
- Ornithine phenylacetate (OP) demonstrates a multi-faceted mechanism for reducing ammonia levels.
- OP shows potential as a safe and effective treatment for hyperammonemia and hepatic encephalopathy in liver failure.
- Further clinical trials are expected to establish OP as a standard therapy for HE.
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