L-Ornithine phenylacetate (OP): a novel treatment for hyperammonemia and hepatic encephalopathy.

Abstract:

:Hepatic encephalopathy (HE) is a common neuropsychiatric complication of liver disease affecting about 20-30% patients with cirrhosis. HE may only affect quality of life (e.g. impairments in attention; coordination; driving ability), but in some patients this progresses to coma and death; defining mortality in those with acute liver failure. HE is thought to occur through accumulation of ammonia as a by-product of protein metabolism. In liver failure ammonia accumulates to toxic levels, resulting in ammonia-associated brain swelling. Presently, there is no proven therapy for HE though recent studies suggest that during liver failure, ammonia removal by skeletal muscle (by conversion to glutamine) can be manipulated; also that ammonia and amino acid metabolism should be viewed in terms of their interorgan relationship. This led us to develop a novel concept for ammonia removal. Preliminary studies provide the proof of concept that the combination of L-ornithine (amino acid) with phenylactetate, as L-ornithine phenylacetate (OP), reduces toxic levels of ammonia by (1) L-ornithine acting as a substrate for glutamine synthesis from ammonia in skeletal muscle and (2) phenylacetate excreting the ornithine-related glutamine as phenylacetylglutamine in the kidneys. As both L-ornithine and phenylacetate are already available for human use, data showing its usefulness in ammonia lowering could translate quickly into providing the much needed therapy for HE patients.

journal_name

Med Hypotheses

journal_title

Medical hypotheses

authors

Jalan R,Wright G,Davies NA,Hodges SJ

doi

10.1016/j.mehy.2006.12.061

subject

Has Abstract

pub_date

2007-01-01 00:00:00

pages

1064-9

issue

5

eissn

0306-9877

issn

1532-2777

pii

S0306-9877(07)00207-1

journal_volume

69

pub_type

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