Presented at the Neonatal Society 2012 Autumn Meeting.

Burgess L¹, Morgan C¹, Mayes K², Tan M²

¹ Department of Neonatology, Liverpool Women’s Hospital, UK 
² Alder Hey Children’s Hospital, LIverpool, UK

Background: We have previously shown that improving early protein intake is associated with a reduction in insulin-treated hyperglycaemia in preterm infants <29 weeks gestation (1). While the exact mechanism for this effect is unknown, the affect of amino acids (AA) on insulin secretion is well described in preterm infants. Some AAs are more potent secretogoges than others. The arginine stimulation test is routinely used in clinical adult practice to assess insulin secretion by the pancreas. Similar neonatal effects have been demonstrated but the implications of arginine intake for the hyperglycaemic preterm infant has not been studied. We hypothesised that low arginine levels would be associated with an increase in insulin treated hyperglycaemia and higher mean daily blood glucose levels (day1-15) in infants born <29 weeks gestation.

Methods: We used the methods described in our previous study (1) to perform a secondary analysis on the data from a previous randomised controlled trial comparing a hyperalimentation and a standard neonatal PN regimen (control) (2). The hyperalimentation regimen was designed to provide 20% more carbohydrate than the control regimen thereby providing a greater test of glucose tolerance for these infants. Daily carbohydrate and protein intake data and mean daily blood glucose and insulin use data from the first 15 days of life were substratified according to high arginine (highARG) or low arginine (lowARG) levels on day 8-10. The threshold for high/low arginine was 57micromol/l (based on the median plasma level in a separate reference population).

Results: Of the 60 control group infants (C) with day 8-10 arginine data, 41 were substratified to the lowARG group and 19 to the highARG group. There were no differences in basic demographic factors likely to affect blood glucose. There were no differences in carbohydrate or protein intake. The blood glucose data replicated our previous findings showing a peak in hyperglycaemia on day 5-10. Low arginine levels were associated higher mean daily blood glucose levels (day 6-10) and more insulin treatment (Table 1; group C). Of the 60 hyperalimentation group infants (H) with day 8-10 arginine data, 33 were substratified to the lowARG group and 22 to the highARG group. LowARG infants were of lower gestation and birthweight (p<0.01) There were no differences in carbohydrate or protein intake. Low arginine levels were associated higher mean daily blood glucose levels (day 1-5, 6-10) and more insulin treatment (Table 1; group H).

Table 1: Mean (SE) blood glucose (mmol/l; 5 day time periods) and insulin use (total days, d1-15)

Conclusion: Low plasma arginine levels in very preterm infants are associated with poorer blood glucose control (measured by mean daily blood glucose and insulin treatment). Further RCT evidence is required.

Corresponding author: colin.morgan@lwh.nhs.uk

References
1. Mahaveer A, Grime C, Morgan C. Nutr Clin Pract;27:399-405.
2. Tan M, Cooke R. Arch Dis Child Fetal Neonatal Ed 2008;93:F337-341