# Supplementary parenteral arginine corrects hypoargininaemia and rebalances plasma amino acid profiles in very preterm infants receiving parenteral nutrition: A prospective study

## TL;DR

Adding more arginine to the nutrition of very preterm infants improves their amino acid balance and corrects arginine deficiency.

## Contribution

This study shows that increasing arginine in parenteral nutrition rebalances amino acid profiles in very preterm infants.

## Key findings

- Arginine supplementation increased plasma arginine levels significantly compared to standard nutrition.
- Higher arginine intake reduced the overprovision of essential amino acids in plasma profiles.
- Plasma arginine levels decreased after discontinuation of parenteral arginine supplementation.

## Abstract

Plasma amino acid (AA) profiles in parenteral nutrition (PN)–dependent very preterm infants (VPIs) consistently show overprovision of essential AA (EAA) and arginine deficiency. This may have implications for growth and immune/inflammatory responses. Aim: To compare plasma AA profiles on day 3 and day 10 in VPIs receiving standard PN (6.3 g/100 g AA arginine) and arginine‐supplemented PN (18 g/100 g AA) in VPIs at <30 weeks' gestation.

VPIs were allocated (according to intervention PN availability) in a series of separate physiological studies to receive standard PN or arginine‐supplemented PN. This approach led to a final PN AA formulation design containing 18 g/100 g AA. Clinical, nutrition intake, and biochemical data were collected. Point‐of‐care testing was used to measure ammonia levels. Plasma AA levels were measured on days 3, 10 and 30 using ion exchange chromatography.

The highest mean daily arginine intake was on day 7: 521 mg/kg/day (142 mg/kg/day) at a dose of 18 g arginine/100 g parenteral AA. The median day 10 plasma arginine level was 85 (52–146) vs 41 (28–54) µmol/L for 18 g/100 g AA arginine vs control, respectively (P < 0.0001) The equivalent data for total EAA were 896 (750–1142) vs 1220 (1031–1428) µmol/L (P < 0.05) and blood ammonia levels were 46 (24–65) vs 51 (40–62) µmol/L (P = 0.28).

In VPIs, PN arginine supplementation of 18 g/100 g AA increases arginine concentrations and reduces provision of EAA as demonstrated in the plasma AA profile. Higher plasma arginine levels are not sustained once parenteral arginine is discontinued. Blood ammonia levels were not useful in identifying individual arginine deficiency.