Related Experiment Videos
Insulin-like growth factor binding proteins in prepubertal children with insulin-dependent diabetes mellitus
M Knip1, P Tapanainen, F Pekonen
1Department of Pediatrics, University of Oulu, Finland.
Insights
In children with insulin-dependent diabetes mellitus (IDDM), normal growth despite low insulin-like growth factor I (IGF-I) may be linked to normal IGFBP-1 levels. This differs from older patients with IDDM.
Area of Science:
- Pediatric Endocrinology
- Metabolic Disorders
- Growth Factor Biology
Background:
- Insulin-dependent diabetes mellitus (IDDM) in children can present with growth discrepancies.
- Reduced insulin-like growth factor I (IGF-I) is common in IDDM, but linear growth is often maintained.
- The role of insulin-like growth factor binding proteins (IGFBPs) in this phenomenon is unclear.
Purpose of the Study:
- To investigate the relationship between IGFBPs and growth in prepubertal children with IDDM.
- To explore the discrepancy between reduced IGF-I levels and normal growth in pediatric IDDM.
Main Methods:
- Measured plasma concentrations of IGF-I, IGFBP-1, IGFBP-2, IGFBP-3, and free insulin in 24 prepubertal diabetic children and 12 controls.
- Assessed growth hormone response to exercise in both groups.
- Correlated IGFBP levels with IGF-I and assessed the impact of glucose control.
Main Results:
- Diabetic children showed significantly decreased IGF-I and increased free insulin levels.
- IGFBP-2 levels were significantly increased in diabetic children and inversely related to IGF-I.
- IGFBP-1 and IGFBP-3 levels were comparable between diabetic and control groups.
- Growth hormone response to exercise was similar in both groups.
- Poor glucose control correlated with lower IGF-I levels.
Conclusions:
- The absence of elevated IGFBP-1 in prepubertal children with IDDM, unlike older patients, may explain maintained linear growth despite low IGF-I.
- Increased IGFBP-2 may play a role in modulating IGF-I activity in pediatric IDDM.
- These findings highlight specific IGFBP profiles contributing to growth regulation in pediatric diabetes.
Abstract:
To study the possible role of insulin-like growth factor binding proteins (IGFBPs) in the discrepancy between normal or only slightly retarded growth and substantially reduced concentrations of insulin-like growth factor I (IGF-I) in prepubertal children with insulin-dependent diabetes mellitus (IDDM), we measured the plasma concentrations of IGF-I, IGFBP-1, IGFBP-2 and IGFBP-3 and free insulin in 24 prepubertal diabetic subjects and 12 control children. In addition, the growth hormone response to exercise was evaluated. The diabetic children had significantly decreased peripheral IGF-I levels (8.2 + 1.1 (SEM) vs 16.7 + 2.5 nmol/l; p < 0.001), whereas the concentrations of free insulin were increased (217 + 14 vs 103 + 21 pmol/l; p < 0.001). The concentrations of IGFBP-1 and IGFBP-3 were of the same magnitude in both groups. The diabetic children had significantly increased levels of IGFBP-2 (465 + 13 vs 416 + 14 micrograms/l; p = 0.029), which were inversely related to the circulating IGF-I levels (r = -0.35; p = 0.034). The diabetic and control children had comparable growth hormone responses to exercise. Diabetic children with poor glucose control had even lower IGF-I levels than those with moderate metabolic control (6.0 + 0.8 vs 10.3 + 1.7 nmol/l; p = 0.037). No differences could be observed in the plasma concentrations of various IGFBPs between these two groups of diabetic subjects. The absence in prepubertal diabetic children of increased IGFBP-1 levels observed in adolescent and adult patients with IDDM may contribute to their maintained linear growth, despite definitely decreased IGF-I concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)