Effect of Hyperalimentation and Insulin‐Treated Hyperglycemia on Tyrosine Levels in Very Preterm Infants Receiving Parenteral Nutrition

Abstract

Hyperalimentation can result in paradoxically low plasma tyrosine levels associated with an increase in insulin-treated hyperglycemia.

Biological Impact of Recent Guidelines on Parenteral Nutrition in Preterm Infants

“…In addition to careful monitoring of serum glucose level in PN-fed preterm infants, exogenous insulin infusion is efficient and may be used with caution. Paradoxically, low plasma tyrosine levels associated with an increase in insulin-treated hyperglycemia have been recently reported (32). Early higher amino acid intake significantly increases insulin plasma concentration and could therefore decrease glucose intolerance (26).…”

High Protein Intake Does Not Prevent Low Plasma Levels of Conditionally Essential Amino Acids in Very Preterm Infants Receiving Parenteral Nutrition

“…‐ 21 Some AAs are unstable in parenteral formulations limiting PN content (tyrosine, glutamine, and cysteine), whereas for other AAs, there appears to be a particularly high demand in the PN‐dependent VPI (arginine). We have previously published plasma AA data demonstrating this potential deficiency using Primene (AA‐P; Baxter, Newbury, UK) as the PN AA source 22 . However, the actual AA intakes in this study fell well below the target AA intakes.…”

“…Figure 1B shows the same data for SCAMP infants and indicates the imbalance is not improved by increasing total AA intake. We have previously published plasma AAs 22 from a similarly designed RCT in the same infant population: the ExPN study 25 . The median (IQR) sampling period was also day 9 (8–10) in both groups, and IEC was used for the plasma AA analysis.…”

“… Compares the plasma amino acid (AA) data in the (A) control and (B) standardized, concentrated, added macronutrients parenteral (SCAMP) groups with the (C) control and (D) intervention groups of the similarly designed ExPN study 22 , 25 using the same reference population. The individual median plasma AA levels and interquartile range have been converted to percentages of the corresponding reference plasma AA mean (reference mean = 100).…”

Current trends and future challenges in neonatal parenteral nutrition

“…A greater risk of hyperglycemia (defined as serum glucose levels >120 mg/dL) was associated with increased length of mechanical ventilation and length of hospital stay in infants with sepsis [39]. The use of insulin to treat TPN-associated hyperglycemia was found to decrease protein synthesis [40]. Guidelines allow insulin administration for TPN-associated hyperglycemia [15,24], however, recent surveys of NICU protocols showed extremely variable targets for glucose control and insulin use [41,42].…”