Levels of bone collagen markers in preterm infants: relation to antenatal glucocorticoid treatment

Perinatal Risk Factors and Genu Valgum Conducive to the Onset of Growing Pains in Early Childhood

The most prevalent musculoskeletal disorder of childhood with unclear aetiology is growing pains (GPs). Anatomic deformities and factors that change bone turnover are implicated in GP pathophysiology. Perinatal risk factors alter the bone metabolism affecting the bone mineral density and content. The aim of our study was to analyze the relationship between GPs, knock knees and perinatal factors. The examined population consisted of 276 children aged 3–7 years. Among them, ten pairs of dizygotic twins were evaluated. The data were collected by using a combination of semi-structured questionnaires, clinical examinations and medical charts of the children and the obstetric history of the mothers. A total of 78 children presenting GPs met Peterson’s criteria. Genu valgum severity was a significant factor for GP manifestation and for their increased frequency and intensity. Subsequently, perinatal factors regarding gestational age, Apgar score, head circumference (lower than 33 cm) and birth length or weight (smaller than 50 cm and 3000 g, respectively) made a remarkable contribution to the development of GPs. Conversely, antenatal corticosteroid treatment, increased maternal age and maternal smoking during pregnancy were not predictive of the disorder. Our data are potentially supportive for the “bone strength” theory and for the contribution of anatomical disturbances in GP appearance.

Influence of Antenatal Glucocorticosteroid Exposure on Osteoprotegerin and Receptor Activator of Nuclear Factor x03BA;B Ligand Levels in Newborn Infants

BACKGROUND/AIMS

The physiologic relevance of osteoprotegerin (OPG) and the receptor activator of nuclear factor x03BA;B ligand (RANKL) in the preterm neonate is unknown. The aim of this study was to examine the effects of prematurity on OPG and RANKL concentrations at birth and to investigate in particular whether antenatal corticosteroid (ACS) exposure affects serum OPG and RANKL levels in premature neonates.

METHODS

Quantitative determination (enzyme immunoassay) of serum OPG and RANKL at 24 postnatal hours was performed in 47 healthy term neonates, 43 preterm newborns not exposed to ACS, and 55 preterm infants exposed to ACS.

RESULTS

OPG in the ACS-exposed preterm group (median 5.13 pmol/l, range 1.62-15.12) was significantly higher compared to preterm neonates not exposed to ACS (median 4.52 pmol/l, range 0.86-8.98, p < 0.05) and to unexposed term neonates (median 4.47 pmol/l, range 2.70-10.72, p < 0.05). Conversely, there was no difference in RANKL levels between the study groups. OPG and RANKL values were also similar between term and preterm neonates not exposed to ACS.

CONCLUSIONS

Preterm neonates exposed to ACS have higher serum levels of OPG, while premature neonates not exposed to ACS have serum OPG and RANKL levels similar to those measured in healthy term neonates.

Quantitative ultrasound measurements in premature infants at 1 year of age: the effects of antenatal administered corticosteroids

The aim of this study was to evaluate the effects of antenatally administered glucocorticoids on bone status of preterm infants at 1 year corrected age. The study population consisted of 32 preterm infants with a gestational age of 24-34 weeks. The infants were divided into two groups according to antenatal exposure to corticosteroids. Quantitative ultrasound (QUS) assessment of bone was performed in the study infants at the corrected age of 1 year. Blood levels of carboxy-terminal propeptide of type I procollagen (PICP) and carboxy-terminal telopeptide of type I collagen (ICTP) were measured at birth and at 1 year corrected age. Levels of PICP and ICTP were significantly lower at birth in corticosteroid-exposed neonates (P < 0.05). At corrected age of 12 months ICTP levels remained significantly lower in corticosteroid-exposed infants, but we found no significant difference in levels of the bone-formation marker PICP between corticosteroid-exposed and nonexposed infants. In the majority of participant preterm infants bone speed of sound (SOS) was within age-adjusted normal values of full-term infants. There was no significant difference in bone SOS between exposed and nonexposed infants at corrected age of 12 months. There was no correlation between SOS and levels of bone markers. The results of our study indicate that, despite the suppression of fetal bone turnover at birth in corticosteroid-exposed infants, antenatal glucocorticoid treatment seems to have no long-term impact on bone status of preterm infants assessed by QUS complementary to measurement of bone-turnover markers at 1 year corrected age.

Bone metabolism in fetuses of pregnant women exposed to single and multiple courses of corticosteroids

OBJECTIVE

To estimate the effect of single and recurrent doses of antenatal corticosteroids on fetal bone metabolism.

METHODS

This was a secondary analysis of a cohort of pregnant women from a previously reported randomized, placebo-controlled, multicenter trial of women at risk for preterm delivery who received weekly courses of betamethasone (active) or placebo after an initial course of corticosteroids. Umbilical cord serum levels of carboxy-terminal carboxy-terminal propeptide of type I procollagen and cross-linked carboxy-terminal telopeptide of type I procollagen were measured to assess the rate of fetal bone formation and resorption, respectively. Analysis was stratified according to number of repeat antenatal study courses of betamethasone or placebo (one to three compared with at least four courses, not including the initial course).

RESULTS

Of the 251 umbilical cord serum samples, the median serum carboxy-terminal telopeptide of type I procollagen levels, but not carboxy-terminal propeptide of type I procollagen levels, was significantly lower with repeat betamethasone exposure (55.0 compared with 57.9 micrograms/L, P=.01). In the fetuses exposed to at least four repeat study courses, there was a significant decrease in median carboxy-terminal telopeptide of type-I procollagen levels between repeat betamethasone exposure and placebo (53.4 compared with 58.6 micrograms/L, respectively, P=.04), but there was no difference between groups in the fetuses exposed to 1-3 repeat study courses (57.4 compared with 56.7 micrograms/L, respectively, P=.29).

CONCLUSION

Levels of umbilical cord serum markers of bone resorption but not formation are reduced in fetuses exposed to repeat courses of antenatal betamethasone. Up to four courses of antenatal betamethasone do not seem to affect fetal bone metabolism.

LEVEL OF EVIDENCE

II.

Short-term effects of glucocorticoid therapy on biochemical markers of bone metabolism in Japanese patients: a prospective study

Glucocorticoid (GC) therapy induces rapid bone loss, but the early changes in calcium and bone metabolism in patients treated with GC have not been clarified. To investigate the changes in calcium and bone metabolism during the early stage of GC therapy, we analyzed various biochemical markers of bone metabolism. The serum levels of calcium (Ca), phosphorus, parathyroid hormone (PTH), osteocalcin (OC), bone alkaline phosphatase (BAP), and type I collagen cross-linked N-telopeptide (NTx), as well as the urinary levels of Ca, creatinine, and NTx, were measured on days 0, 3, 7, and 28 of GC therapy. The subjects were divided into the following four groups: 9 patients receiving pulse therapy (P), 18 patients receiving prednisolone (PSL) at doses > or =40 mg/day (H), 9 patients receiving PSL at doses > or =20 mg/day (M), and 11 patients receiving PSL at doses < or =10 mg/day (S). The serum OC level showed a marked decrease on day 3 of GC therapy (-41.2% +/- 6.6%, P < 0.01), while the BAP level decreased gradually. Both serum and urinary NTx levels significantly increased on day 7 of GC therapy (9.9% +/- 4.5%, P < 0.05, and 42.2% +/- 10.6%, P < 0.01, respectively). Urinary Ca excretion was increased on day 3 of GC therapy and continued to increase until 4 weeks, while intact PTH showed an increase on day 3 and then remained constant until 4 weeks. In groups P and H, there were significant early changes in OC, BAP, NTx, and intact PTH levels, as well as urinary Ca excretion. Even a PSL dose of <10 mg/day caused a decrease in the serum OC level. In conclusion, the biochemical markers of Ca and bone metabolism showed different kinetics depending on the dose of GC, and it is important for patients on high-dose GC therapy to receive prophylaxis for bone loss from the start of GC treatment.