Growth patterns in the growth-retarded premature infant

Dynamic influence of maternal education on height among Chinese children aged 0-18 years

Background

Maternal education is one of key factors affecting nurturing environment which significantly impacts children's height levels throughout their developmental stages. However, the influence of maternal education on children's height is less studied. This study aims to investigate the dynamic influence of maternal education on children's height among Chinese children aged 0-18 years.

Methods

Children undergoing health examinations from January 2021 to September 2023 were included in this study. Clinical information including height, weight, maternal pregnancy history, blood specimens for bone metabolism-related indicators and maternal education level was collected. Children's height was categorized into 14 groups based on age and gender percentiles, following WHO 2006 growth standards. One-way analysis of variance (ANOVA), linear regression, chi-square test and Fisher's exact test were applied for data analysis.

Results

A total of 6269 samples were collected, including 3654 males and 2615 females, with an average age of 8.38 (3.97) for males and 7.89 (3.55) for females. Significant correlations between maternal education level, birth weight, birth order, weight percentile, vitamin D, serum phosphorus, alkaline phosphatase levels, and children's height were identified. Birth weight's influence on height varied across age groups. Compared with normal birth weight children, low birth weight children exhibited catch-up growth within the first 6 years and a subsequent gradual widening of the height gap from 6 to 18 years old. Remarkably, the impact of maternal education on height became more pronounced among children above 3-6 years old, which can mitigate the effect of low birth weight on height.

Conclusion

We found that weight percentile, birth weight, birth order, bone marker levels, and maternal education level have significant effect on height. Maternal education attenuates the impact of low birth weight on height. The findings indicated that maternal education plays a consistent and critical role in promoting robust and healthy growth.

The Exon 3-Deleted Growth Hormone Receptor (d3GHR) Polymorphism-A Favorable Backdoor Mechanism for the GHR Function

Growth hormone (GH) is a peptide hormone that plays a crucial role in controlling growth, development, and lifespan. Molecular regulation of GH is accomplished via the GH receptor (GHR), which is the main factor influencing human development and is essential to optimal functioning of the GH/IGF-I axis. Two GHR isoforms have been studied, according to the presence (flGHR) or absence (d3GHR) of exon 3. The d3GHR isoform, which lacks exon 3 has recently been related to longevity; individuals carrying this isoform have higher receptor activity, improved signal transduction, and alterations in the treatment response and efficacy compared with those carrying the wild type (WT) isoform (flGHR). Further, studies performed in patients with acromegaly, Prader-Willi syndrome, Turner syndrome, small for gestational age (SGA), and growth hormone deficiency (GHD) suggested that the d3GHR isoform may have an impact on the relationship between GH and IGF-I levels, height, weight, BMI, and other variables. Other research, however, revealed inconsistent results, which might have been caused by confounding factors, including limited sample sizes and different experimental methods. In this review, we lay out the complexity of the GHR isoforms and provide an overview of the major pharmacogenetic research conducted on this ongoing and unresolved subject.

Growth Patterns of Children With Short Stature in Adulthood According to Auxological Status and Maturity at Birth

CONTEXT

Prematurity carries a risk for impaired postnatal growth and long-term growth restriction. Especially children born SGA seem vulnerable for poor growth, as a persistent short stature can be observed in app 10-15% of these children.

OBJECTIVE

In this study we aimed to recognize differences in growth patterns of children according to sex, maturity, and auxological status at birth facilitating earlier identification of small-for-gestational-age (SGA) children with adult short stature.

METHODS

The growth data of 44 791 infants born between January 1, 1980, and December 30, 2012, among 2 pediatric cohorts with follow-up through December 31, 2020, were analyzed. A total of 5698 children with birth data had measurements at near final height (nfh) and at least 2 further points.

RESULTS

Preterm children (gestational age < 37 weeks) had a significantly lower mean nfh SDS than term children (preterm, -0.61; term, -0.18) and a higher likelihood of nfh < third percentile (preterm, 20.5%; term, 12.2%). SGA born children also had a lower mean nfh SD score (SDS) than children born appropriate for gestational age (AGA) (SGA, -1.06; AGA, -0.15) and a higher likelihood of nfh < third percentile (SGA, 28.2%; AGA 10.1%). Of 1204 SGA children, 672 (56%) showed successful catch-up growth (CUG) to nfh greater than or equal to the 10th percentile (SGA-CU), and 532 children (44%) did not (SGA-S). The difference in their mean nfh SDS (SGA-CU, -0.12; SGA-S -2.26) can only partly be explained by the differences in mean mid-parental height SDS (SGA-CU, -0.3; SGA-S, -1.19). During the first year, SGA-CU showed higher CUG (SGA-CU, +1.2 SDS; SGA-S, +0.45 SDS), which helps to discriminate between groups earlier.

CONCLUSION

Final growth outcome was influenced by prematurity and auxological status at birth, but not by sex. Height/length SDS increments during year 1 are instrumental to discern SGA children with later normal or short stature. While observing CUG until year 2 and 3 can add specificity, discrimination thereafter becomes difficult.

Application of Machine Learning Approaches to Predict Postnatal Growth Failure in Very Low Birth Weight Infants

PURPOSE

The aims of the study were to develop and evaluate a machine learning model with which to predict postnatal growth failure (PGF) among very low birth weight (VLBW) infants.

MATERIALS AND METHODS

Of 10425 VLBW infants registered in the Korean Neonatal Network between 2013 and 2017, 7954 infants were included. PGF was defined as a decrease in Z score >1.28 at discharge, compared to that at birth. Six metrics [area under the receiver operating characteristic curve (AUROC), accuracy, precision, sensitivity, specificity, and F1 score] were obtained at five time points (at birth, 7 days, 14 days, 28 days after birth, and at discharge). Machine learning models were built using four different techniques [extreme gradient boosting (XGB), random forest, support vector machine, and convolutional neural network] to compare against the conventional multiple logistic regression (MLR) model.

RESULTS

The XGB algorithm showed the best performance with all six metrics across the board. When compared with MLR, XGB showed a significantly higher AUROC (p=0.03) for Day 7, which was the primary performance metric. Using optimal cut-off points, for Day 7, XGB still showed better performances in terms of AUROC (0.74), accuracy (0.68), and F1 score (0.67). AUROC values seemed to increase slightly from birth to 7 days after birth with significance, almost reaching a plateau after 7 days after birth.

CONCLUSION

We have shown the possibility of predicting PGF through machine learning algorithms, especially XGB. Such models may help neonatologists in the early diagnosis of high-risk infants for PGF for early intervention.

Long-term effectiveness of growth hormone therapy in children born small for gestational age: An analysis of LG growth study data

Purpose

Growth hormone (GH) treatment has been used to improve growth in short children who were born small for gestational age (SGA). The aim of this study was to investigate the long-term efficacy of GH treatment in these children.

Methods

Data from a multicenter observational clinical trial (ClinicalTrials.gov NCT01604395, LG growth study) were analyzed for growth outcome and prediction model in response to GH treatment. One hundred fifty-two children born SGA were included.

Results

The mean age of patients born SGA was 7.13 ± 2.59 years. Height standard deviation score (SDS) in patients born SGA increased from -2.55 ± 0.49 before starting treatment to -1.13 ± 0.76 after 3 years of GH treatment. Of the 152 patients with SGA, 48 who remained prepubertal during treatment used model development. The equation describing the predicted height velocity during 1st year of GH treatment is as follows: the predictive height velocity (cm) = 10.95 + [1.12 x Height SDS at initial treatment (score)] + [0.03 x GH dose (ug/kg/day)] + [0.30 x TH SDS at initial treatment (score)] + [0.05 x age (year)] + [0.15 x Weight SDS at initial treatment (score)] ± 1.51 cm.

Conclusions

GH treatment improved growth outcome in short children born SGA. We also developed a prediction model that is potentially useful in determining the optimal growth outcome for each child born SGA.

Trial registration

ClinicalTrials.gov Identifier: NCT01604395.

Growth patterns of preterm infants in Korea

With advancements in neonatal care and nutrition, the postnatal growth of preterm infants has improved; however, it remains an issue. Accurate assessments of growth using a standardized reference are needed to interpret the intrauterine and postnatal growth patterns of preterm infants. Growth in the earlier periods of life can contribute to later outcomes, and the refinement of postnatal growth failure is needed to optimize outcomes. Catchup growth occurs mainly before discharge and until 24 months of age, and very low birth weight infants in Korea achieve retarded growth later in life. Knowing an infant's perinatal history, reducing morbidity rates during admission, and performing regular monitoring after discharge are required. Preterm infants with a lower birth weight or who were small for gestational age are at increased risk of poor neurodevelopmental outcomes. Furthermore, poor postnatal growth is predictive of adverse neurodevelopmental outcomes. Careful monitoring and early intervention will contribute to better development outcomes and national public health improvements.

Identification of Growth Patterns in Low Birth Weight Infants from Birth to 5 Years of Age: Nationwide Korean Cohort Study

This study aimed to investigate the nationwide growth pattern of infants in Korea according to the birth-weight group and to analyze the effect of growth on development. A total of 430,541 infants, born in 2013 and who received the infant health check-up regularly from 6 months to 60 months of age, were included. The weight, height, head circumferences percentiles, and neurodevelopment using screening tests results were compared among the birth-weight groups. Using longitudinal analysis, the study found a significant difference in height, weight, and head circumference, respectively, according to age at health check-up, birth weight group, and combination of age and birth weight (p < 0.001). The growth parameters at 60 months of age showed a significant correlation with those at 6 months of age especially in extremely low birth weight infants. The incidence of suspected developmental delay was significantly higher in infants with growth below the 10th percentiles than in those with growth above the 10th percentiles. Among 4571 (1.6%) infants with suspected developmental delay results at 60 months of age, birth weight, sex, and poor growth parameters were confirmed as associated factors. This nationwide Korean study shows that poor growth and neurodevelopment outcomes persisted among low-birth-weight infants at 60 months of age. Our findings provide guidance for developing a nationwide follow-up program for infants with perinatal risk factors in Korea.

Diagnosis and management of postnatal fetal growth restriction

Fetal growth restriction (FGR) can result from multiple causes, such as genetic, epigenetic, environment, hormonal regulation, or vascular troubles and their potential interaction. The physiopathology of FGR is not yet fully elucidated, but the insulin-like growth factor system is known to play a central role. Specific clinical features can lead to the identification of genetic syndromes in some patients. FGR leads to multiple global health concerns, from the perinatal period, with higher morbidity/mortality, through infancy, with neurodevelopmental, growth, and metabolic issues, to the onset of puberty and later in life, with subfertility and elevated risks of cardiovascular and kidney diseases. Adequate follow-up and therapeutics should be offered to these patients. We first review the main molecular etiologies leading to FGR and their specificities. We then highlight the main issues that FGR can raise later in life before concluding with the proposed management of these children.

Prediction of Postnatal Growth Failure among Very Low Birth Weight Infants

Postnatal growth failure (PGF) in preterm infants remains an important clinical issue. In this study, we analysed the incidence of PGF among very low birth weight (VLBW) infants and evaluated the risk factors for PGF based on the data of 2799 VLBW infants obtained from the Korean Neonatal Network database from 2013 to 2014. PGF was defined as a decrease in weight Z score between birth and discharge of more than −1.28 using the Fenton growth charts. Risk factors were evaluated in relation to birth weight for gestational age, namely small (SGA) or appropriate (AGA) for gestational age, using propensity score matching used for between-group differences. The overall incidence of PGF was 45.5%, with a rate of 68.9% in the SGA group and 36.2% in the AGA group. PGF was negatively correlated with gestation and birth weight; additionally, PGF was associated with a higher incidence of co-morbidities. Predictors of PGF in the SGA group were respiratory distress syndrome and days to attain 100 mL/kg of enteral feeding. The only predictor of PGF in the AGA group was days to attain 100 mL/kg of enteral feeding. Early initiation and aggressive progression of enteral nutrition may decrease the incidence of PGF.

Recombinant Bile Salt-Stimulated Lipase in Preterm Infant Feeding: A Randomized Phase 3 Study

INTRODUCTION

Feeding strategies are critical for healthy growth in preterm infants. Bile salt-stimulated lipase (BSSL), present in human milk, is important for fat digestion and absorption but is inactivated during pasteurization and absent in formula. This study evaluated if recombinant human BSSL (rhBSSL) improves growth in preterm infants when added to formula or pasteurized breast milk.

PATIENTS AND METHODS

LAIF (Lipase Added to Infant Feeding) was a randomized, double-blind, placebo-controlled phase 3 study in infants born before 32 weeks of gestation. The primary efficacy variable was growth velocity (g/kg/day) during 4 weeks intervention. Follow-up visits were at 3 and 12 months. The study was performed at 54 centers in 10 European countries.

RESULTS

In total 415 patients were randomized (rhBSSL n = 207, placebo n = 208), 410 patients were analyzed (rhBSSL n = 206, placebo n = 204) and 365 patients were followed until 12 months. Overall, there was no significantly improved growth velocity during rhBSSL treatment compared to placebo (16.77 vs. 16.56 g/kg/day, estimated difference 0.21 g/kg/day, 95% CI [-0.40; 0.83]), nor were secondary endpoints met. However, in a predefined subgroup, small for gestational age infants, there was a significant effect on growth in favor of rhBSSL during treatment. The incidence of adverse events was higher in the rhBSSL group during treatment.

CONCLUSIONS

Although this study did not meet its primary endpoint, except in a subgroup of infants small for gestational age, and there was an imbalance in short-term safety, these data provide insights in nutrition, growth and development in preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01413581.

The ProVIDe study: the impact of protein intravenous nutrition on development in extremely low birthweight babies

BACKGROUND

Preterm birth and very small size at birth have long-term effects on neurodevelopment and growth. A relatively small percentage of extremely low birthweight babies suffer from severe neurological disability; however, up to 50% experience some neurodevelopmental or learning disability in childhood. Current international consensus is that increased protein intake in the neonatal period improves both neurodevelopment and growth, but the quantum of protein required is not known. This trial aims to assess whether providing an extra 1 to 2 g.kg(-1).d(-1) protein in the first 5 days after birth will improve neurodevelopmental outcomes and growth in extremely low birthweight babies.

METHODS/DESIGN

The ProVIDe study is a multicentre, two-arm, double-blind, parallel, randomised, controlled trial. In addition to standard intravenous nutrition, 430 babies with a birthweight of less than 1000 g who have an umbilical arterial line in situ will be randomised in 1:1 ratio to receive either an amino acid solution (TrophAmine®) or placebo (saline) administered through the umbilical arterial catheter for the first 5 days. Exclusion criteria are admission to neonatal intensive care more than 24 h after birth; multiple births of more than 2 babies; known chromosomal or genetic abnormality, or congenital disorder affecting growth; inborn error of metabolism, and in danger of imminent death.

PRIMARY OUTCOME

Survival free from neurodevelopmental disability at 2 years' corrected age, where neurodevelopmental disability is defined as cerebral palsy, blindness, deafness, developmental delay (standardised score more than 1 SD below the mean on the cognitive, language or motor subscales of the Bayley Scales of Infant Development Edition 3), or Gross Motor Function Classification System score ≥ 1.

SECONDARY OUTCOMES

Growth, from birth to 36 weeks' corrected gestational age, at neonatal intensive care discharge and at 2 years' corrected age; body composition at 36 to 42 weeks' corrected postmenstrual age and at 2 years' corrected age; neonatal morbidity, including length of stay; nutritional intake.

DISCUSSION

This trial will provide the first direct evidence of the effects of giving preterm babies a higher intake of intravenous protein in the first week after birth on neurodevelopmental outcomes at 2 years corrected age.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12612001084875.

Different expression of placental pyruvate kinase in normal, preeclamptic and intrauterine growth restriction pregnancies

INTRODUCTION

Preeclampsia (PE) and intrauterine growth restriction (IUGR) are two diseases that affect pregnant women and their unborn children. These diseases cause low birth weight, pre-term delivery, and neurological and cardiovascular disorders in babies. Combined they account for 20% of preterm deliveries. Pyruvate kinase M2 (PKM2) is a metabolism enzyme found in developing embryonic and cancer tissues. Our objective is to determine the expression of PKM2 in human PE and IUGR compared to normal pregnancies. Understanding expression of PKM2 in PE and IUGR could help us to better understand the mechanisms and find treatments for PE and IUGR.

METHODS

Human placental tissues were obtained for PKM2 determination and analyzed by immunohistochemistry, Western blot, and a pyruvate assay. Placental samples were homogenized and cytoplasmic and nuclear proteins were extracted for Western blot analysis.

RESULTS

Preeclampsia samples had elevated levels of p-PKM2, p-ERK, and ERK in the cytoplasm. Beta-catenin and lactose dehydrogenase (LDH) were also elevated in preeclampsia placenta samples.

DISCUSSION AND CONCLUSION

We conclude that PKM2 is expressed in normal, PE and IUGR pregnancies. Also, that this expression is increased in the PE placenta at delivery. These results suggest placental metabolism through PKM2 could play a role in human preeclampsia.

Three-year growth response to growth hormone treatment in very young children born small for gestational age-data from KIGS

CONTEXT

Children born small for gestational age (SGA) with poor growth during the first years of life may remain short in stature during childhood and as adults.

OBJECTIVE

To evaluate the 3-year growth response to GH treatment in very young short children born SGA, and to test the existing predictions models for growth response developed for older SGA children.

SETTING

KIGS (The Pfizer International Growth Database).

PATIENTS

A total of 620 SGA children (birth length and/or weight below -2 SD score [SDS]) on GH treatment, 156 in the 2- to 4-year-old group (100 boys; median age, 3.3 y), and 464 in the 4- to 6-year-old group (284 boys; median age, 4.9 y).

RESULTS

Median values and 10th-90th percentiles are presented. Both groups presented a significant increase in height velocity during GH treatment. Median height SDS increased from -3.9 (-5.4 to -2.9) at the start to -2.2 (-3.8 to -1.0) at 3 years in the 2- to 4-year-old group (P < .01) and from -3.4 (-4.5 to -2.6) to -2.0 (-3.3 to -0.9) in the 4- to 6-year-old group (P < .01). Median weight SDS increased from -3.8 (-5.9 to -2.4) to -2.1 (-4.1 to -0.5) in the 2- to 4-year-old group (P < .01). Respective values for the 4- to 6-year-old group were -3.1 (-4.8 to -1.8) to -1.6 (-3.1 to -0.1) SDS (P < .01). First- and second-year growth response could be estimated by the SGA model.

CONCLUSION

Very young children born SGA without spontaneous catch-up growth presented a significant improvement in height and weight during the 3 years of GH treatment. Growth response could be estimated by the SGA model.

rhBSSL improves growth and LCPUFA absorption in preterm infants fed formula or pasteurized breast milk

OBJECTIVES

Preterm infants often experience suboptimal growth, which can affect organ development. The aim of this study was to improve growth by treatment with bile salt-stimulated lipase (BSSL), naturally present in breast milk, but lost after pasteurization, and absent in formula.

METHODS

Two clinical trials were performed with a predefined analysis of combined data to investigate the effects of recombinant human BSSL (rhBSSL) treatment on growth velocity and fat absorption in preterm infants. The studies were randomized and double-blinded comparing 7-day treatment with rhBSSL and placebo, administered in pasteurized breast milk or formula, using a crossover design.

RESULTS

Sixty-three infants were evaluated for safety. At randomization, the mean (standard deviation) weight was 1467 (193) g and mean postmenstrual age was 32.6 (0.5) weeks. Sixty and 46 infants were evaluated for growth velocity and fat absorption, respectively. rhBSSL treatment significantly improved mean growth velocity by 2.93 g · kg · day (P<0.001) compared with placebo (mean 16.86 vs 13.93 g · kg · day) and significantly decreased the risk of suboptimal growth (<15 g · kg · day) (30% vs 52%, P=0.004). rhBSSL significantly increased absorption of the long-chain polyunsaturated fatty acids, docosahexaenoic acid, and arachidonic acid by 5.76% (P=0.013) and 8.55% (P=0.001), respectively, but had no significant effect on total fat absorption. The adverse-event profile was similar to placebo.

CONCLUSIONS

In preterm infants fed pasteurized breast milk or formula, 1 week of treatment with rhBSSL was well tolerated and significantly improved growth and long-chain polyunsaturated fatty acid absorption compared to placebo. This publication presents the first data regarding the use of rhBSSL in preterms and the results have led to further clinical studies.

The contribution of preterm birth and intrauterine growth restriction to childhood undernutrition in Tanzania

Objectives were to examine the growth patterns of preterm and growth-restricted infants and to evaluate the associations of prematurity and intrauterine growth restriction (IUGR) with risk of stunting, wasting and underweight. Data from a cohort of HIV-negative pregnant women-infant pairs were collected prospectively in Tanzania. Small for gestational age [SGA, birthweight (BW) <10th percentile] was used as proxy for IUGR. Anthropometry was measured monthly until 18 months. Length-for-age (LAZ), weight-for-length (WLZ), and weight-for-age (WAZ) z-scores were calculated using the 2006 World Health Organization (WHO) Child Growth Standards. Stunting, wasting and underweight were defined as binary outcomes using a cut-off of <-2 SD of the respective z-scores. Multivariate Cox proportional hazard models were used to assess the associations between preterm and SGA to time to stunting, wasting and underweight. The study included 6664 singletons. Preterm and appropriate for gestational age (AGA) infants had slightly better nutritional status than term-SGA infants and despite some catch-up growth, preterm-SGA infants had the poorest nutritional status. The gap in LAZ and WAZ z-scores among the groups remained similar throughout the follow-up. Compared with term-AGA babies, relative risk (RR) of stunting among preterm-AGA babies was 2.13 (95% confidence interval (CI) 1.93-2.36), RR among term-SGA was 2.21 (95% CI 2.02-2.41) and the highest risk was among the babies who were both preterm and SGA (RR = 7.58, 95% CI 5.41-10.64). Similar magnitude of RR of underweight was observed among the three groups. Preterm and SGA infants should be closely monitored for growth failure. Intervention to reduce preterm and SGA birth may lower risk of undernutrition in resource-limited settings.

Increased protein intake decreases postnatal growth faltering in ELBW babies

OBJECTIVE

To determine whether purposely designed nutritional guidelines for extremely low birthweight (ELBW; birth weight <1000 g) babies result in protein intakes that meet international consensus recommendations, and whether this results in improved growth from birth to discharge.

DESIGN

A prospective cohort study of nutritional intakes and growth in ELBW babies.

SETTING

A tertiary neonatal intensive care unit in New Zealand.

PATIENTS

100 ELBW babies who survived for the first month of life, 50 before the introduction of the guideline (Lo Pro) and 50 after (Hi Pro).

INTERVENTION

Introduction of a nutritional guideline aimed at increasing protein intakes to meet international consensus recommendations.

MAIN OUTCOME MEASURES

Weekly protein intakes over the first month of life and growth until discharge.

RESULTS

Hi Pro babies had significantly higher protein intakes in the first month of life than Lo Pro babies (mean (SD), 3.8 (0.3) vs 3.3 (0.4) g/kg.day, p<0.0001) and a significantly greater growth velocity (GV) over the first 30 days after regaining birth weight (19.5 (5.0) vs 16.2 (5.4) g/kg.day, p<0.002). Hi Pro babies had a significantly lesser Z-score change between birth and discharge than Lo Pro babies for weight (0.0 (1.2) vs -0.9 (1.1), p=0.001), length (-0.8 (0.8) vs -1.2 (1.1), p=0.02) and head circumference (-0.2 (1.1) vs -1.1 (1.6), p<0.001).

CONCLUSIONS

Simple, standardised nutritional guidelines can result in recommended protein intakes for ELBW babies being achieved and result in increased GV. Downward crossing of centiles between birth and discharge, common in ELBW babies, is significantly reduced for weight, length and head circumference.

Growth hormone treatment in short children born prematurely--data from KIGS

CONTEXT

Children born prematurely with growth failure might benefit from GH treatment.

OBJECTIVES

The aim was to evaluate the first year growth response to GH treatment in short children born prematurely and to identify predictors of the growth response.

DESIGN/PATIENTS

A total of 3215 prepubertal children born prematurely who were on GH treatment were selected from KIGS (The Pfizer International Growth Database), a large observational database. They were classified according to gestational age as preterm (PT; 33 to no more than 37 wk) and very preterm (VPT; <33 wk), and according to birth weight as appropriate for gestational age [AGA; between -2 and +2 sd score (SDS)] and small for gestational age (SGA; -2 SDS or below).

RESULTS

Four groups were identified: PT AGA (n = 1928), VPT AGA (n = 629), PT SGA (n = 519), and VPT SGA (n = 139). GH treatment was started at a median age of 7.5, 7.2, 6.7, and 6.0 yr, respectively. After the first year of GH treatment, all four groups presented a significant increase in weight gain and height velocity, with a median increase in height SDS higher than 0.6. Using multiple stepwise regression analysis, 27% of the variation in height velocity could be explained by the GH dose, GH peak during provocative test, weight and age at GH start, adjusted parental height, and birth weight SDS. The first year growth response of the children born PT and SGA could be estimated by the SGA model published previously.

CONCLUSION

Short children born prematurely respond well to the first year of GH treatment. Long-term follow-up is needed.

Influence of insulin-like growth factor I and nutrition during phases of postnatal growth in very preterm infants

Pronounced growth restriction (GR) occurs after very preterm birth. The interaction between IGF-I, nutritional intake, and growth was evaluated prospectively in 64 infants with a mean (SD) GA of 25.7 (1.9) wk. Blood sampling of IGF-I and measurements of weight, length, and head circumference were performed weekly until discharge. Daily calculation of nutritional intake was performed. Standard deviation scores (SDSs) for growth parameters defined two growth phases: GR phase (birth until lowest SDS) and catch-up (CU) phase (lowest SDS until 35 gestational weeks). IGF-I concentrations during the first postnatal weeks were low and increased at 30 wk GA, irrespective of GA at birth, coinciding with initiation of CU growth. Concentrations of IGF-I were positively associated with change in weight SDS during the GR phase, p = 0.001 and CU phase, p = 0.004-0.027. Protein and energy intake were not associated with change in SDS weight during the GR phase as opposed to the CU phase (p < 0.001, respectively). Nutritional intake did not correlate to concentrations of IGF-I before 30 wk GA. IGF-I is associated with growth at an earlier postnatal age than nutrient intake and the effect of nutrition on levels of IGF-I may be restricted to the period of established CU growth.

Involucrin–claudin-6 tail deletion mutant (CΔ206) transgenic mice: a model of delayed epidermal permeability barrier formation and repair

Preterm birth is a major global health problem that results in a large number of infant deaths, many of which are attributable to the complications of an immature epidermal permeability barrier (EPB), for which there is currently no effective therapeutic option. The mammalian EPB is formed during development and is essential for survival as it maintains thermoregulation and hydration, and provides a defense against infection. Using transgenic mouse technology, we have demonstrated the importance of claudin (Cldn)-containing tight junctions (TJs) in epidermal differentiation and, in particular, that epidermal suprabasal overexpression of Cldn6 results in an EPB-deficient phenotype that phenocopies the dysfunctional EPB of premature human infants. In this study, we used the same approach to target a Cldn6 tail deletion mutant to the epidermis of mice [involucrin (Inv)-Cldn6-CΔ206 transgenic mice]. The Inv-Cldn6-CΔ206 transgenic mice displayed a developmental delay in EPB formation, as shown by the expression of keratins and Cldns, and by X-Gal penetration assays. Trans-epidermal water loss measurements and immunolocalization studies indicated that the epidermal differentiation program was also perturbed in postnatal Inv-Cldn6-CΔ206 transgenic mice resulting in a delayed maturation. Notably, however, expression/localization of epidermal differentiation and maturation markers, including Cldns, indicated that the transgenic epidermis matured and normalized by postnatal day 10, which is 3 days after the wild-type epidermis. Our results suggest that activation of the extracellular signal-regulated kinase 1/2 (Erk1/2) pathway and Cldn1 phosphorylation are associated with the repair and maturation of the skin barrier processes. These studies provide additional support for the crucial role of Cldns in epidermal differentiation, maturation and the formation of the EPB, and describe a novel animal model for evaluating postnatal epidermal maturation and therapies that may accelerate the process.