Response to IGF-1 Generation Test in Short Prepubertal Children Born Very Preterm or at Term
Harriet L Miles1, José G B Derraik, Valentina Chiavaroli
1Liggins Institute, University of Auckland, Auckland, New Zealand.
Insights
Short children born very preterm do not show growth hormone (GH) resistance. However, they exhibit indirect evidence of insulin resistance, which may contribute to their short stature.
Area of Science:
- Pediatric Endocrinology
- Neonatal Research
- Growth Disorders
Background:
- Short stature in children born very preterm is a clinical concern.
- The potential role of growth hormone (GH) resistance in this population requires investigation.
Purpose of the Study:
- To determine if very preterm infants born short for their gestational age exhibit GH resistance compared to term-born peers.
- To explore potential underlying mechanisms for short stature in this cohort.
Main Methods:
- A cohort of 26 prepubertal children with short stature was studied (11 very preterm, 15 term-born).
- An insulin-like growth factor-1 (IGF-1) generation test using recombinant human GH (rhGH) was administered over 4 days.
- Hormone and binding protein levels were measured at baseline and after stimulation.
Main Results:
- Baseline differences included lower IGF-binding protein 1 (IGFBP-1) and IGFBP-3 in preterm children.
- Following rhGH stimulation, IGF-1 and IGFBP-3 increased similarly in both groups.
- Preterm children showed higher GH-binding protein (GHBP), insulin, and leptin levels, with lower IGFBP-1 post-stimulation.
Conclusions:
- Short children born very preterm do not demonstrate GH resistance as a cause for their short stature.
- Indirect evidence suggests insulin resistance in very preterm children, aligning with previous findings.
Aims:
To investigate whether short children born very preterm (<32 weeks of gestation) exhibit features of growth hormone (GH) resistance compared to term peers.
Methods:
We studied 26 prepubertal children (aged 7.0 ± 2.0 years) with short stature (height adjusted for parents' heights <10th percentile), who were born appropriate for gestational age and either very preterm (n = 11) or at term (n = 15). Children underwent insulin-like growth factor-1 (IGF-1) generation test via a daily recombinant human GH (rhGH) dose (0.05 mg/kg/day) over 4 consecutive days. Hormone and binding proteins were measured at baseline and day 5.
Results:
At baseline, preterm children had lower IGF-binding protein 1 (IGFBP-1; -22%; p = 0.049) and IGFBP-3 (-24%; p = 0.013) concentrations than term children. Preterm children also had insulin concentrations that tended to be 39% higher (p = 0.059) than term peers. After stimulation, IGF-1 and IGFBP-3 concentrations increased similarly in term and preterm groups, while GH-binding protein (GHBP) concentrations decreased in both groups. Preterm children had higher GHBP (+50%; p = 0.049), insulin (+86%; p = 0.005), and leptin (+107%; p = 0.020) but lower IGFBP-1 (-47%; p = 0.006) concentrations than term children following rhGH stimulation.
Conclusions:
Preterm children who are short for genetic height potential show no evidence of GH resistance that would explain their short stature. However, there was indirect evidence of insulin resistance in the preterm children, as previously described in this group.
