The nutritional management of urea cycle disorders

Leonard, James V.

doi:10.1067/mpd.2001.111835

Cited by 63 publications

(43 citation statements)

References 21 publications

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“…Amino acid profiles are a powerful determinant in the management of patients with a UCD and are considered a requisite in the follow-up of these patients (Leonard 2001;Summar and Tuchman 2001). The rationale for this study was to provide information about the most likely plasma amino acid pattern in patients with a UCD at the time of decompensation and presentation to hospital, in order to guide appropriate treatment prescription.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, in order to enhance anabolism, supplementation of essential amino acids enriched with BCAA along with sufficient calories to patients with a UCD during acute decompensation and hyperammonaemia would seem prudent. Moreover, in view of the contribution of the splanchnic system to protein retention and metabolism (Newsholme et al 2003), it would be advantageous to treat patients who present with metabolic decompensation through enteral supplementation, as previously suggested (Leonard 2001;Summar 2001), rather than intravenously.…”

Section: Discussionmentioning

confidence: 99%

“…Amino acid profiles are a powerful determinant in the management of patients with a UCD and are considered a requisite in the follow-up of these patients (Leonard 2001;Summar 2001). However, there are very few published reports in which sufficient attention has been given to the timing of blood sampling (fasting hours), in order to obtain meaningful blood concentrations that can serve for therapeutic decision making.…”

Section: Introductionmentioning

confidence: 99%

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Amino Acid Profiles in Patients with Urea Cycle Disorders at Admission to Hospital due to Metabolic Decompensation

Rodney

Boneh

2012

JIMD Reports

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Urea cycle disorders (UCDs) result from inherited defects in the ammonia detoxification pathway, leading to episodes of hyperammonaemia and encephalopathy. The purpose of this study was to answer the question, "what is the likely plasma amino acid profile of a patient known to have a UCD presenting with hyperammonaemia during acute metabolic decompensation", in order to support informed decisions regarding management.We analysed the results of plasma ammonia levels and amino acid profiles taken simultaneously or within 30 min of each other during acute admissions of all patients with a UCD at the Royal Children's Hospital, Melbourne, over 28 years. Samples from 96 admissions (79, 9 and 8 admissions for OTC, CPS and ASS deficiencies, respectively) from 14 patients fulfilled these criteria. Amino acid levels were measured by ion exchange chromatography with post-column ninhydrin derivatisation and interpreted in relation to age-related reference ranges.Plasma concentrations of all measured essential amino acids were low or low-normal in almost all samples. There was a strong positive correlation between low plasma branched-chain amino acids and other essential amino acids, and a negative correlation between ammonia and phenylalanine to tyrosine (Phe:Tyr) ratio in patients with OTC deficiency, and between glutamine and Phe:Tyr ratio in all patients, indicating protein deficiency.Conclusion: At admission, protein deficiency is common in patients with a UCD with hyperammonaemia. These results challenge the current guideline of stopping protein intake during acute decompensation in UCDs. Supplementation with essential amino acids (particularly branched-chain amino acids) at these times should be considered.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Amino Acid Profiles in Patients with Urea Cycle Disorders at Admission to Hospital due to Metabolic Decompensation

Rodney

Boneh

2012

JIMD Reports

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“…As part of the urea cycle it is a potent stimulator of urea production, and as such it is often administered to patients with inborn errors of the urea cycle to reduce the hyperammonaemia that is symptomatic to the disorder (Leonard, 2001). It may therefore also be useful as a treatment for urea cycle impairment in IUGR.…”

Section: Introductionmentioning

confidence: 99%

Urea production and arginine metabolism are reduced in the growth restricted ovine foetus

Boo

Zijl

Lafeber

et al. 2007

Animal

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Urea production may be impaired in intrauterine growth restriction (IUGR), increasing the risk of toxic hyperammonaemia after birth. Arginine supplementation stimulates urea production, but its effects in IUGR are unknown. We aimed to determine the effects of IUGR and arginine supplementation on urea production and arginine metabolism in the ovine foetus. Pregnant ewes and their foetuses were catheterised at 110 days of gestation and randomly assigned to control or IUGR groups. IUGR was induced by placental embolisation. At days 120 and 126 of gestation, foetal urea production was determined from [ 14 C]-urea kinetics and arginine metabolism was determined from the appearance of radioactive metabolites from [ 3 H]-arginine, both at baseline and in response to arginine or an isonitrogenous mixed amino acid supplementation. Urea production decreased with gestational age in the embolised animals (13.9^3.1 to 11.2^3.0 mmol/kg per min, P # 0.05) but not in the controls (13.3^3.5 to 14.8^6.0 mmol/kg per min). Arginine supplementation increased urea production in both groups, but only at 126 days of gestation (control: 15.0^8.5 to 17.0^9.4 mmol/kg per min; embolised: 11.7^3.1 to 14.3^3.1 mmol/kg per min, P # 0.05). Embolisation reduced foetal arginine concentrations by 20% ( P # 0.05) while foetal arginine consumption was reduced by 27% ( P # 0.05). The proportions of plasma citrulline and hydroxyproline derived from arginine were reduced in the embolised animals. These data suggest that foetal urea production and arginine metabolism are perturbed in late gestation after placental embolisation.

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“…[2][3][4] Current conservative long-term treatment regimens include dietary manipulation with a low-protein diet to decrease substrate load on the urea cycle while providing sufficient essential amino acids and sufficient calories to prevent or decrease catabolism. 5,6 Patients are treated with nitrogen scavengers (sodium benzoate, sodium phenylbutyrate) to provide an alternative pathway for nitrogen excretion. 7,8 Arginine, the deficiency of which results from decreased synthesis due to the block in argininosuccinate lyase, becomes an essential amino acid and therefore needs to be supplemented exogenously.…”

mentioning

confidence: 99%

Liver transplantation for argininosuccinic aciduria: Clinical, biochemical, and metabolic outcome

et al. 2007

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We report successful liver transplantation in a young adult with argininosuccinic aciduria but without cirrhosis. Plasma amino acid profile normalized and brain magnetic resonance spectroscopy indicated improved metabolism after transplantation. The general well-being of the patient and his quality of life improved. We suggest that orthotopic liver transplantation should be considered for patients with argininosuccinic aciduria even in the absence of cirrhosis, with the aim of correcting (at least in part) central nervous system metabolism, thereby preventing further neurological deterioration. Liver Transpl 14: 41-45, 2008.

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The nutritional management of urea cycle disorders

Cited by 63 publications

References 21 publications

Amino Acid Profiles in Patients with Urea Cycle Disorders at Admission to Hospital due to Metabolic Decompensation

Amino Acid Profiles in Patients with Urea Cycle Disorders at Admission to Hospital due to Metabolic Decompensation

Urea production and arginine metabolism are reduced in the growth restricted ovine foetus

Liver transplantation for argininosuccinic aciduria: Clinical, biochemical, and metabolic outcome

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