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Context The human adrenal cortex changes with fetal-neonatal transition from the fetal to the adult organ, accompanied by changes in the steroid metabolome. Objective As it is unclear how the observed developmental changes differ between preterm and full-term neonates, we investigated whether the involution of the fetal adrenals is following a fixed time course related to postmenstrual age or whether it is triggered by birth. Furthermore, the fetal and postnatal androgen metabolome of preterm infants was characterized in comparison to term babies. Methods This was a prospective, longitudinal, 2-center study collecting spot urines of preterm and term infants during the first 12 to 18 months of life. Steroid metabolites were measured from spot urines by gas chromatography–mass spectrometry. Data relating were modeled according to established pre- and postnatal pathways. Results Fetal adrenal involution occurs around term-equivalent age in preterm infants and is not triggered by premature birth. Testosterone levels are higher in preterm infants at birth and decline slower until term compared to full-term babies. Dihydrotestosterone levels and the activity of the classic androgen biosynthesis pathway are lower in premature infants as is 5α-reductase activity. No difference was found in the activity of the alternate backdoor pathway for androgen synthesis. Conclusion Human adrenal involution follows a strict timing that is not affected by premature birth. By contrast, prematurity is associated with an altered androgen metabolome after birth. Whether this reflects altered androgen biosynthesis in utero remains to be investigated.

The hormone fibroblast growth factor 21 (FGF21) is a key metabolic regulator in the adaptation to fasting. In food-restricted mice, inhibition of skeletal growth is mediated by the antagonistic effect of FGF21 on GH action in the liver and growth plate.The objective of the study was to assess the role of FGF21 in growth regulation in humans using postnatal growth failure of very preterm infants as a model.FGF21 levels were measured serially in very preterm infants, and their linear growth evaluated from birth to term-equivalent age. Primary chondrocytes obtained from pediatric donors were used to test whether FGF21 can directly interfere with GH signaling.A negative association (β -.415, P.005, linear regression model) of FGF21 levels with the change in SD score for length was found. In primary chondrocytes, FGF21 upregulated basal and GH-induced SOCS2 expression and inhibited GH-induced signal transducer and activator of transcription 5 (STAT5) phosphorylation as well as GH-induced COLII and ALP expression. Finally, FGF21 inhibited GH-induced IGF-1 expression and cell proliferation, indicating GH resistance. However, FGF21 did not affect IGF-1-induced cell proliferation.Elevated FGF21 serum levels during the first weeks of life are independently associated with postnatal growth failure in preterm infants. Furthermore, our data provide mechanistic insights into GH resistance secondary to prematurity and may offer an explanation for the growth failure commonly seen in chronic conditions of childhood.

Giant cell tumors (GCTs) of the bone are rare, usually benign but locally aggressive neoplasms that primarily occur in the epiphyses of long bones. They seldom develop in the cranium; when they do, they involve principally the sphenoid and temporal bones. These tumors usually affect young adults, and few reports in children have been published. Primary malignant GCTs of the skull are even more uncommon. The 3 published cases all involved adults over 40 years of age. Herein, the authors present a case of a highly aggressive primary malignant GCT of the posterior fossa in a 5-week old preterm infant. One month after the gross-total resection of the tumor found in the bone, the infant's condition rapidly deteriorated and she died. Magnetic resonance imaging and postmortem examination revealed a tumor larger than it had been before the operation, with expansion toward the brain. To the best of the authors' knowledge, this is the youngest patient reported with a primary malignant GCT of the skull, and actually the first case in a pediatric patient. In addition, the extremely high growth rate of the tumor in the postoperative period renders this case the most aggressive primary malignant GCT of the cranium described so far.