Circulating peptide YY concentrations are higher in preterm than full-term infants and correlate negatively with body weight and positively with serum ghrelin concentrations.

BACKGROUND: Peptide YY (PYY) and ghrelin are gastrointestinal tract-derived hormones that play roles in the regulation of food intake and energy balance. Negative energy balance often occurs in hospitalized preterm infants. METHODS: To measure serum concentrations of PYY in preterm and full-term infants and to investigate their correlations with anthropometric characteristics, food intake, and serum ghrelin concentrations, we measured serum PYY and ghrelin concentrations by RIA in 62 healthy preterm infants [mean (SD) gestational age, 32.0 (2.1) weeks; postnatal age, 40.9 (14.8) days] and 15 healthy full-term infants of comparable postnatal age. All of the infants were formula-fed every 3 h. RESULTS: PYY concentrations were significantly higher in preterm [1126.2 (215.4) ng/L] than in full-term infants [825.3 (234.4) ng/L; P < 0.001]. In the entire study population, serum PYY concentrations correlated negatively with gestational age and anthropometric measurements (birth weight, body weight, body length, body mass index, and head circumference) and positively with serum ghrelin concentrations, whereas there was no significant correlation between PYY concentration and caloric intake or weight gain. Multiple regression analysis, after correction for prematurity, revealed that serum PYY concentrations correlated independently with serum ghrelin concentrations and infant body weight or body mass index. CONCLUSIONS: Circulating concentrations of PYY may increase in preterm infants to compensate for the negative body-weight balance. The physiologic mechanisms behind the correlation between PYY and ghrelin remain to be elucidated.

Hyperglycaemia and insulinopenia in a neonate with cystic fibrosis.

UNLABELLED: Abnormal glucose tolerance is a frequent late complication of cystic fibrosis (CF), but the prevalence of CF-related diabetes mellitus (CFRD) in children less than 10 y old is less than 2%. The youngest child with CFRD reported to date was 6 mo of age. Insulinopenia is the primary cause of abnormal glucose tolerance/CFRD, but it is unknown whether it may begin in the neonatal period. We describe a case of a neonate with CF who presented with hyperglycaemia in the diabetic range and marked insulinopenia. Insulinopenia and impaired glucose tolerance were permanent findings at 6 and 15 mo of age. CONCLUSION: This case suggests that abnormal glucose tolerance/diabetes may occur much earlier in the course of CF, even during neonatal age. Careful follow-up and further studies in CF infants could reveal that the real incidence of glucose intolerance and diabetes in this age group has been underestimated.

Serum lipids in preterm infants fed a formula supplemented with nucleotides.

BACKGROUND: The effect of dietary nucleotides on lipid metabolism has been the subject of clinical studies with conflicting results. We measured serum triglycerides, total cholesterol (total-C), and lipoprotein cholesterol levels (HDL-C, LDL-C, and VLDL-C) in preterm neonates fed formula with and without nucleotide supplements. METHODS: This prospective, randomized, controlled study included 150 healthy preterm neonates (gestational age, 33.0 +/- 1.9 weeks) matched for gestational age, birth weight, and gender. Subjects were assigned at birth to receive either a standard milk formula supplemented with nucleotides (group F-NT) or the same formula without nucleotides (group F). Serum was obtained before discharge (29.1 +/- 10.0 days of life) and triglycerides, total-C, and HDL-C were determined enzymatically. LDL-C and VLDL-C were estimated by the Friedewald formula. For statistical analysis t test, Mann Whitney-U test, two-way ANOVA, and chi2 test were used, as appropriate. The influence of several factors on serum lipid levels was evaluated by linear regression analysis. RESULTS: Serum triglycerides, total-C, and VLDL-C levels did not differ between groups. HDL-C levels (median; 25th-75th percentiles) were significantly higher (P < 0.001) in group F-NT (48.0 mg/dL; 40.5-57.0 mg/dL) than in group F (34.5 mg/dL; 27.2-44.0 mg/dL). On the contrary, LDL-C levels (median; 25th-75th percentiles) were significantly lower (P < 0.001) in group F-NT (39.0 mg/dL; 26.0-54.0 mg/dL) than in group F (65.0 mg/dL; 41.0-73.0 mg/dL). In the multiple regression analysis, nucleotide supplementation was identified as one of the controlled independent factors influencing serum HDL-C and LDL-C levels. CONCLUSIONS: Preterm neonates fed from birth with formula supplemented with nucleotides have significantly higher HDL-C and lower LDL-C serum levels than do neonates fed unsupplemented formula. The clinical relevance of these results remains to be elucidated.