Effect of Two Amino Acid Solutions on Leucine Turnover in Preterm Infants

Branched-chain amino acid supplementation for improving growth and development in term and preterm neonates

BACKGROUND

Branched-chain amino acids (BCAAs) play a vital role in neonatal nutrition. Optimal BCAA supplementation might improve neonatal nutrient storage, leading to better physical and neurological development and other outcomes.

OBJECTIVES

To determine the effect of BCAA supplementation on physical growth and neurological development in term and preterm neonates. We planned to make the following comparisons: parenteral nutrition with and without BCAA supplementation; enteral BCAA supplementation versus no supplementation; and any type of supplementation including enteral, parenteral and both ways versus no supplementation. To investigate the supplementation effectiveness for different dosages assessed in the eligible trials.

SEARCH METHODS

We conducted comprehensive searches using Cochrane Neonatal's standard search strategies: Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 6), MEDLINE, Embase and CINAHL (up to July 2016). We updated the search with CENTRAL (2019, Issue 8), MEDLINE, Embase and CINAHL (up to August 2019). We also searched clinical trials registries and reference lists of retrieved articles.

SELECTION CRITERIA

We planned to include individual and cluster-randomised and quasi-randomised controlled trials comparing BCAA supplementation versus placebo or no supplementation in term and preterm neonates. We excluded trials presented only as abstracts and cross-over trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of all potential studies identified from the search strategy. We planned to extract data using a pilot-tested standard data extraction form and assess risk of bias of the included studies following the methods described in the Cochrane Handbook for Systematic Reviews of Interventions. We planned to analyse treatment effects and report their effect estimates as per dichotomous or continuous data with 95% confidence intervals. We planned to conduct subgroup analysis to investigate heterogeneity, and perform sensitivity analysis where possible. We planned to use fixed-effect meta-analysis to combine data wherever appropriate. We planned to assess evidence quality using the GRADE approach.

MAIN RESULTS

We did not identify any potentially eligible studies that met the inclusion criteria in this review.

AUTHORS' CONCLUSIONS

We found no trial data to support or refute the idea that BCAA supplementation affects physical and neurological development and other outcomes in term and preterm neonates.

Two parenteral amino acid solutions and plasma levels of amino acids in the neonate: A randomized trial

OBJECTIVE

In neonates on total parenteral nutrition (TPN), amino acids may be a risk factor for developing total parenteral nutrition-associated cholestasis (TPNAC). We aimed, first, to compare methionine, cysteine, and taurine plasma levels between neonates on TPN who were receiving an intravenous amino acid solution based on a breast milk aminogram and those on an intravenous solution of pediatric amino acids based on an umbilical cord aminogram, and second, to determine the frequency of TPNAC.

METHODS

A double-blind randomized controlled trial was conducted. Ninety-four neonates with a birthweight of 1000g or more and a gestational age of 30 wk or older were admitted and enrolled. Blood samples were obtained at 0, 7, and 14 d of TPN, and plasma amino acid concentrations were determined by ultra-high-resolution liquid chromatography. Continuous variables were compared using the Wilcoxon rank-sum test or Student's t test; categorical variables were compared using the Fisher exact test.

RESULTS

Thirty-five neonates completed the study (Primene, n = 14; TrophAmine, n = 21). On day 14, methionine plasma concentrations were significantly lower in the Primene group than in the TrophAmine group (27 µmol/L versus 32.9 µmol/L, P = 0.044); the taurine concentration was significantly higher in the same group (72.4 µmol/L versus 45.3 µmol/L, P < 0.0001). There were no differences in TPNAC incidence.

CONCLUSIONS

Administering an intravenous solution of pediatric amino acids based on the umbilical cord aminogram yielded a higher taurine and lower methionine plasma concentration than did administering a similar solution based on the breast milk aminogram.

Nutritional strategy of early amino acid administration in very low birth weight infants

Relative to a fetus of the same gestational age, very low birth weight (VLBW) infants are more likely to be underfed and to undergo growth restriction during their early hospital stay. The current trend towards "early and aggressive" nutritional strategies in VLBW infants aims to overcome the early nutritional deficiency and thereby boost postnatal catch-up growth, simultaneously improving long-term neurodevelopmental outcomes. Although the minimum starting amino acid (AA) dose to prevent negative nitrogen balance is well established, the upper limit and the rate of increase of early AA doses are controversial. Most randomized controlled trials show that early and high-dose (target, 3.5 to 4.9 g/kg/day) AA regimens, with or without high nonprotein calories, do not improve long-term growth and neurodevelopment. High-dose AA supplementation may lead to early metabolic disturbances and excessive or disproportionate plasma AA levels, particularly in infants of very low gestational age. Further large studies are needed to clarify the optimal strategy for early administration of parenteral AA doses in VLBW infants.

Effect of low versus high early parenteral nutrition on plasma amino acid profiles in very low birth-weight infants

OBJECTIVE

To study the efficacy of early high doses parenteral nutrition (PN) versus early low dose with progressive increments PN regimens, we performed a prospective randomized study in very low birth-weight infants.

STUDY DESIGN

Forty-one appropriate gestational age preterm infants with birth weights ranging from 750-1500 g were randomly assigned into two groups. In Group 1, infants started on 3.0 g/kg/day amino acids (AA) and 3 g/kg/day of 20% lipid; in Group 2, AA and lipid were started on 1 g/kg/day, and advanced over 3 days to a maximum 3 g/kg/day. Blood samples were obtained for AA concentrations before starting of the PN, and at the 7th and 14th days.

RESULTS

The mean (±SD) birth weight was 1335 g (240), gestational age was 29.7 weeks (1.7) of the study group. The mean body weight and head circumference was similar in the Group 1 and Group 2 at the 14th postnatal days. There was no difference in the blood levels of triglyceride, blood urea nitrogen, creatinine, ammonia, lactat and bicarbonate in the two groups. There was no significant difference in the concentrations of AA except for arginine and asparagine. On day 14, the mean arginine concentrations were significantly higher and asparagine concentrations were lower in Group 2.

CONCLUSION

Although earlier more aggressive administration of AA and fat is not associated with any significant metabolic abnormalities, growth rates and plasma AA concentrations of the infants were similar to infants who AA and lipid given lower in the first day of life.

Total sulfur amino acid requirement and metabolism in parenterally fed postsurgical human neonates

BACKGROUND

Except for tyrosine, the amino acid requirements of human neonates receiving parenteral nutrition (PN) have not been experimentally derived.

OBJECTIVES

The objectives were to determine the total sulfur amino acid (TSAA) requirement (methionine in the absence of cysteine) of postsurgical, PN-fed human neonates by using the indicator amino acid oxidation (IAAO) technique with L-[1-(13)C]phenylalanine as the indicator.

DESIGN

Fifteen postsurgical neonates were randomly assigned to receive 1 of 18 methionine intakes ranging from 10 to 120 mg x kg(-1) x d(-1), delivered in a customized, cysteine-free amino acid solution. Breath and urine samples were collected for the measurement of (13)CO(2) and amino acid enrichment. Blood samples were collected at baseline and after the test methionine infusion for the measurement of plasma methionine, homocysteine, cystathionine, and cysteine concentrations.

RESULTS

Breakpoint analysis determined the mean TSAA requirements to be 47.4 (95% CI: 38.7, 56.1) and 49.0 (95% CI: 39.9, 58.0) mg x kg(-1) x d(-1) with the use of oxidation and F(13)CO(2), respectively.

CONCLUSIONS

This is the first study to report the TSAA requirement of postsurgical, PN-fed human neonates. The estimated methionine requirement expressed as a proportion of the methionine content of current commercial pediatric PN solutions was 90% (range: 48-90%) of that found in the lowest methionine-containing PN solution.