GH treatment induces sustained catch-up growth in children with intrauterine growth retardation: 7-year results

Height and body mass index in molecularly confirmed Silver-Russell syndrome and the long-term effects of growth hormone treatment

OBJECTIVE

Silver-Russell syndrome (SRS) causes short stature. Growth hormone (GH) treatment aims to increase adult height. However, data are limited on the long-term outcomes of GH in patients with molecularly confirmed SRS. This study evaluated height, body mass index (BMI) and GH treatment in molecularly confirmed SRS.

DESIGN

An observational study with retrospective data collection.

PATIENTS

Individuals with molecularly confirmed SRS aged ≥13 years.

MEASUREMENTS

Data were collected on height, height gain (change in height standard deviation score [SDS] from childhood to final or near-final height), BMI and gain in BMI (from childhood to adulthood) and previous GH treatment.

RESULTS

Seventy-one individuals (40 female) were included. The median age was 22.0 years (range 13.2-69.7). The molecular diagnoses: H19/IGF2:IG-DMR LOM in 80.3% (57/71); upd(7)mat in 16.9% (12/71) and IGF2 mutation in 2.8% (2/71). GH treatment occurred in 77.5% (55/71). Total height gain was greater in GH-treated individuals (median 1.53 SDS vs. 0.53 SDS, p = .007), who were shorter at treatment initiation (-3.46 SDS vs. -2.91 SDS, p = .04) but reached comparable heights to GH-untreated individuals (-2.22 SDS vs. -2.74 SDS, p = .7). In GH-treated individuals, BMI SDS was lower at the most recent assessment (median -1.10 vs. 1.66, p = .002) with lower BMI gain (2.01 vs. 3.58, p = .006) despite similar early BMI SDS to GH-untreated individuals (median -2.65 vs. -2.78, p = .3).

CONCLUSIONS

These results support the use of GH in SRS for increasing height SDS. GH treatment was associated with lower adult BMI which may reflect improved metabolic health even following discontinuation of therapy.

3-M syndrome associated with growth hormone deficiency: 18 year follow-up of a patient

3-M syndrome is a rare autosomal recessive disorder that causes short stature, unusual facial features and skeletal abnormalities. Mutations in the CUL7, OBSL1 and CCDC8 genes could be responsible for 3-M syndrome.Here we describe the growth and evolution of dismorphic features of an Italian boy with 3-M syndrome and growth hormone deficiency (GHD) from birth until adulthood. He was born full term with a very low birth weight (2400 g=-3.36 standard deviation score, SDS) and length (40.0 cm =-6.53 SDS). At birth he presented with a broad, fleshy nose with anteverted nostrils, thick and patulous lips, a square chin, curvilinear shaped eyebrows without synophrys, short thorax and long slender bones. Then, during childhood tall vertebral bodies, hip dislocation, transverse chest groove, winged scapulae and hyperextensible joints became more evident and the diagnosis of 3-M syndrome was made; this was also confirmed by the finding of a homozygous deletion in exon 18 of the CUL7 gene, which has not been previously described.The patient also exhibited severe GHD (GH <5 ng/ml) and from the age of 18 months was treated with rhGH. Notwithstanding the early start of therapy and good compliance, his growth rate was always very low, except for the first two years of treatment and he achieved a final height of 132 cm (-6.42 SDS).

Russell Silver syndrome: a perspective on growth and the influence of growth hormone therapy

A 6 years male child was referred to our Endocrinology clinic with complaints of failure to thrive and he displayed the characteristic features of Russell Silver Syndrome which included short stature, relative macrocephaly, triangular facies and bilateral clinodactyly. He had a birth weight of 2.14 kg and an expected target height of 170 cm. He was subjected to a hormonal analysis which revealed a normal thyroid profile, but low serum markers of growth namely IGF-1=68 ng/ml (52-297 ng/ml) and basal growth hormone (GH) (1.5 μg/l). No defects were detected on MRI of the sella. Therefore a growth hormone stimulation test with Clonidine was performed which confirmed complete GH deficiency (at 0 min=0.16 μg/l, 60 min=0.27 μg/l, 120 min=4.73 μg/l). He was commenced on rhGH therapy at 8 years of age (height=102 cm, SDS=-4.53), due to financial restraints. Following initiation of GH therapy (1.5 IU/day) for 19 months, a height gain of 15 cm was obtained (Height=117 cm, SDS=-3.05). Bone age at 9 yr. was between 7-8 years.

Prediction models for short children born small for gestational age (SGA) covering the total growth phase. Analyses based on data from KIGS (Pfizer International Growth Database)

BACKGROUND

Mathematical models can be developed to predict growth in short children treated with growth hormone (GH). These models can serve to optimize and individualize treatment in terms of height outcomes and costs. The aims of this study were to compile existing prediction models for short children born SGA (SGA), to develop new models and to validate the algorithms.

METHODS

Existing models to predict height velocity (HV) for the first two and the fourth prepubertal years and during total pubertal growth (TPG) on GH were applied to SGA children from the KIGS (Pfizer International Growth Database)--1st year: N = 2340; 2nd year: N = 1358; 4th year: N = 182; TPG: N = 59. A new prediction model was developed for the 3rd prepubertal year based upon 317 children by means of the all-possible regression approach, using Mallow's C(p) criterion.

RESULTS

The comparison between the observed and predicted height velocity showed no significant difference when the existing prediction models were applied to new cohorts. A model for predicting HV during the 3rd year explained 33% of the variability with an error SD of 1.0 cm/year. The predictors were (in order of importance): HV previous year; chronological age; weight SDS; mid-parent height SDS and GH dose.

CONCLUSIONS

Models to predict growth to GH from prepubertal years to adult height are available for short children born SGA. The models utilize easily accessible predictors and are accurate. The overall explained variability in SGA is relatively low, due to the heterogeneity of the disorder. The models can be used to provide patients with a realistic expectation of treatment, and may help to identify compliance problems or other underlying causes of treatment failure.

IGF-I and IGF Binding Protein-3 Generation Tests and Response to Growth Hormone in Children with Silver-Russell Syndrome

Objectives. To evaluate, in children with Silver-Russell Syndrome, the response to the IGF-I and IGFBP-3 generation test and compare results to the growth response after 6 months of rhGH. Methods. Eight children (6 males), with a mean age of 5.71 ± 2.48 years and height SDS of -3.88 ± 1.28 received rhGH for 6 months. IGF-I and IGFBP-3 were analyzed before and after 4 doses of rhGH. Results. The mean growth velocity (GV) before treatment was 5.28 ± 1.9 cm/year. GV increased after rhGH in five children to a mean GV of 10.3 ± 3.64 cm/year. Six children had normal basal IGF-I levels and two low levels. After 4 doses of rhGH, the IGF-I levels were normal in seven. There was no correlation between the growth response and the IGF-I generation test. Conclusions. Children with SRS have normal IGF-I generation test. There is no correlation between the generation test and the growth velocity after 6 months of rhGH.

Growth hormone treatment for short stature in children born small for gestational age

Children born small for gestational age (SGA) who do not show catch-up in the first 2 years generally remain short for life. Although the majority of children born SGA are not growth hormone (GH) deficient, GH treatment is known to improve average growth in these children.Early studies using GH in children born SGA demonstrated increased height velocity, but these effects tended to be short-term with effects decreasing when GH treatment stopped. With refined GH regimens, significant effects on height have been shown, with gains of approximately 1 standard deviation score after 2 years. Studies have also shown that long-term continuous GH therapy can significantly increase final height to within the normal range. GH treatment of children born SGA does not appear to unduly affect bone age or pubertal development. Growth prediction models have been used to identify various factors involved in the response to GH therapy with age at start, treatment duration, and GH dose showing strong effects. Genetic factors such as the exon 3 deletion of the GH receptor may contribute to short stature of children born SGA and may also be involved in the responsiveness to GH treatment, but there remain other unknown genetic and/or environmental factors. No unexpected safety concerns have arisen in GH therapy trials. In particular, no long-term adverse effects have been seen for glucose metabolism, and positive effects have been shown for lipid profiles and blood pressure.GH treatment in short children born SGA has shown a beneficial, growth-promoting effect in both the short-and long-term, and has become a recognized indication in both the US and Europe. Further studies on individualized treatment regimens and long-term safety are ongoing.

Safety and efficacy of growth hormone treatment in small for gestational age children

PURPOSE OF REVIEW

Approximately 100,000 infants are born small for gestational age (birth weight <2 standard deviation) annually in the US alone. Because of catch-up growth, 10-20% of all children born small for gestational age will be eligible for growth hormone therapy. Growth hormone has been approved by the Food and Drug Administration in 2003 and by the European Agency for the Evaluation of Medical Products though at different enrollment and treatment criteria. Benefits and risks of growth hormone therapy for small for gestational age children are the purpose of the present review.

RECENT FINDINGS

Mean height increased by as much as two standard deviation over 3 years of treatment in infants born small for gestational age. Rapid catch-up growth is desirable and will only be achieved with higher growth hormone doses (0.48 mg/kg/week) Treatment should be continuous and not interrupted. The safety profile of growth hormone treatment is excellent. Transient elevation of insulin levels returned to near normal after growth hormone treatment was discontinued.

SUMMARY

Growth hormone treatment in small for gestational age children has been found to be well tolerated and is an important advance in the treatment of short stature in pediatrics. Treatment of short prematurely born infants with growth hormone may offer similar efficacy and safety as growth hormone treatment in small for gestational age infants.

Perinatal bone turnover in term pregnancies: the influence of intrauterine growth restriction

Intrauterine growth restriction (IUGR) has been associated with low bone mass in infancy and increased risk for osteoporosis development in adult life. We aimed to investigate the effect of IUGR on bone metabolism in mother/infant pairs, by determining circulating biochemical markers of bone turnover in IUGR and appropriate for gestational age (AGA) pregnancies. Circulating markers of bone formation [bone specific alkaline phosphatase (BALP), total alkaline phosphatase (ALP), osteocalcin (OC)] and bone resorption [cross-linked N-telopeptide of type I collagen (NTx)], as well as intact parathormone (PTH), calcium and phosphorus levels were measured in 40 mothers and their 20 IUGR and 20 AGA singleton full-term fetuses and neonates on postnatal days 1 (N1) and 4 (N4). No significant differences in BALP, ALP, OC, NTx, PTH, calcium or phosphorus levels were observed between the AGA and the IUGR groups. In both groups, maternal BALP levels were lower compared to fetal, N1 and N4 levels (p< or =0.005 in all cases). In the AGA group, maternal NTx and OC levels were lower compared to fetal, N1 and N4 levels (p<0.001 in all cases), and fetal NTx levels were lower compared to N1 and N4 ones (p<0.001 and p=0.002, respectively). In the IUGR group, maternal OC levels were lower compared to fetal, N1 and N4 ones (p<0.001 in each case) and fetal OC levels were elevated compared to N1 and N4 ones (p<0.001 and p=0.003, respectively). N4 NTx levels were elevated compared to maternal, fetal and N1 levels (p=0.009, p<0.001 and p=0.002, respectively) and fetal NTx levels were lower compared to N1 and N4 ones (p=0.001 and p<0.001, respectively). Finally, positive correlations were found between maternal NTx and BALP (r=0.332, p=0.037), as well as ALP (r=0.329, p=0.038) levels, and between maternal, fetal, N1, N4 BALP and respective ALP levels (r=0.432, p=0.005, r=0.534, p=0.001, r=0.778, p<0.001, r=0.694, p<0.001, respectively). In conclusion, maternal, fetal and neonatal bone turnover in IUGR cases may not differ from respective bone metabolism in AGA controls. In addition, fetal and neonatal bone remodeling is markedly enhanced and independent of maternal bone turnover in late pregnancy.

Small for gestational age: short stature and beyond

Depending on the definitions used, up to 10% of all live-born neonates are small for gestational age (SGA). Although the vast majority of these children show catch-up growth by 2 yr of age, one in 10 does not. It is increasingly recognized that those who are born SGA are at risk of developing metabolic disease later in life. Reduced fetal growth has been shown to be associated with an increased risk of insulin resistance, obesity, cardiovascular disease, and type 2 diabetes mellitus. The majority of pathology is seen in adults who show spontaneous catch-up growth as children. There is evidence to suggest that some of the metabolic consequences of intrauterine growth retardation in children born SGA can be mitigated by ensuring early appropriate catch-up growth, while avoiding excessive weight gain. Implicitly, this argument questions current infant formula feeding practices. The risk is less clear for individuals who do not show catch-up growth and who are treated with GH for short stature. Recent data, however, suggest that long-term treatment with GH does not increase the risk of type 2 diabetes mellitus and the metabolic syndrome in young adults born SGA.

Growth Hormone Therapy in Short Children Born Small for Gestational Age

There is still a lack of data from randomized, controlled, long-term studies of growth hormone (GH) treatment in children born small for gestational age (SGA), but the available evidence indicates consistently that GH therapy is a valid growth-promoting treatment in these children, particularly if started early. Whilst side effects appear uncommon, ongoing surveillance is required and treated children should be monitored for changes in glucose homeostasis, lipid profiles and blood pressure, especially during puberty. We provide an update on the safety and efficacy of GH treatment in short children born SGA.

Growth hormone therapy in short children born small for gestational age

Being born small for gestational age (SGA) is one of the most common causes of childhood short stature, and recombinant GH therapy has been recently licensed to promote growth in short SGA children from the age of 4 years old. Studies are now reporting very encouraging effects on adult height gains, especially in those children who started GH therapy early, at least 2 years prior to the onset of puberty. Compared to the age at starting treatment, the GH dose has a less significant impact on final height, and more attention needs to be paid now to identify earlier those SGA children who fail to catch-up spontaneously. The benefits are not just in terms of height, but also in body composition and possibly blood pressure and lipid levels. However the risk of side effects and long-term complications, particularly related to the expected metabolic effects of GH in inducing insulin resistance and hyperinsulinaemia, need to be carefully monitored especially in SGA children with a family history of type 2 diabetes. Recently, GH therapy was found to amplify the adrenarche of short SGA children and to induce a pro-inflammatory shift, as judged by a rise of neutrophil count and circulating interleukin-6 (IL-6), and a fall in adiponectin levels. Further progress is anticipated to assess the addition of insulin-sensitizing therapy to attenuate the GH-induced hyperinsulinemia, in order to alter the pro-inflammatory course, to avoid excessive release of adrenal androgens, and to slow down the potential rapid tempo of pubertal progression in SGA children. In the meantime, post-SGA short stature is rapidly becoming one of the prime indications for GH therapy in childhood.

Adult height of prepubertal short children born small for gestational age treated with GH

OBJECTIVE

Human GH (hGH) treatment leads to catch-up growth in children with short stature born small for gestational age (SGA). However, long-term efficacy and safety results in this patient group remain scarce. The present study assessed the efficacy and safety of late childhood treatment with biosynthetic hGH (Humatrope) in a group of short children born SGA (height <-2 standard deviation scores (SDS)).

DESIGN

Patients in this open-label, Phase III, multicenter study received a daily hGH dose of 0.067 mg/kg for 2 years, and then received no treatment for the following 2 years. After the fourth year on study, patients whose height had decreased more than 0.5 SDS but who still showed growth potential based on bone age were allowed to resume treatment until they reached adult height.

METHODS

Height gain SDS was assessed for 11 girls and 24 boys (mean age+/-s.d. 9.6+/-0.9 years) at the end of the 2 years of hGH treatment, during the subsequent 2-year off-treatment period, and upon reaching adult height.

RESULTS

At the end of the initial 2-year treatment period, 83% of patients had reached a height within the normal range, with a mean increase in height SDS vs baseline of 1.3+/-0.3 (P <0.001). Adult heights (n = 20) were within the normal range for 50% of patients, and mean height gain from baseline was statistically significant (0.7+/-0.8 SDS, P <0.001). Fasting glucose and glycosylated hemoglobin levels were not significantly modified during treatment.

CONCLUSIONS

High-dose hGH treatment for a minimum of 2 years in short children born SGA was well tolerated and resulted in a significant increase in adolescent and adult height.

Follow-up height after discontinuation of growth hormone treatment in children with intrauterine growth retardation

Growth hormone (GH) treatment has been used in children with intrauterine growth retardation (IUGR) to promote growth with success in several short- and long-term clinical trials. Intermittent GH therapy has also been advocated in children with IUGR. This study was designed to evaluate the growth of children with IUGR after discontinuation of a two-year trial of GH treatment. Sixteen children (12 F, 4 M) who had received GH (Genotropin) at age 5.3 (1.3) years at a dose of 0.2 IU/kg/day for 2 years (Group 1) and 10 (6 F, 4 M) controls of age 4.3 (1.7) years without treatment (Group 2) were followed after completion of the trial over a median period of 4 years. Height SDS of the GH-treated group showed an increase from -3.0 (0.5) to -1.9 (0.7) (p <0.001) over 2 years of therapy. Off therapy, height SDS decreased to -3.5 (0.5) at a mean age of 11.2 (1.6) years. The difference between the initial and recent height SDS in this group was significantly different (p = 0.02). Height SDS of the control group, -2.7 (1.4) initially, did not change over the two-year observation period. At follow-up, seven control children received GH in a similar fashion for one year. In spite of an insignificant increase in height SDS on one year of GH, it decreased to -2.9 (1.6) at age 11.0 (2.1) years at the latest visit. There was no significant difference between the recent heights of the two groups at final examination. One girl in Group 1 developed acanthosis nigricans and type 2 diabetes mellitus at age 13.3 years, after the follow-up period. A second patient developed osteosarcoma in the left tibia at age 9.9 years, for which she received chemotherapy and surgery. In conclusion, height SDS showed a significant increase on GH therapy for 2 years in children with IUGR; however, it decelerated after discontinuation of therapy. At the final visit, GH therapy did not seem to have had any effect on height prognosis. This finding shows that GH should be given continuously to improve final height in children with IUGR.

Growth hormone treatment in short children with intrauterine growth retardation

The aim of this prospective controlled study was to assess the effect of rhGH in short prepubertal children with intrauterine growth retardation and normal growth hormone status. Twenty-six children were randomized into treatment (12F, 4M) and control (6F, 4M) groups. Mean ages were 5.3 (1.3) yr and 4.3 (1.7) yr, respectively. rhGH (Genotropin) was used at a dose of 0.2 IU/kg/day as daily s.c. injections for two years. In the treated group, mean height SDS increased from -3.0 (0.5) to -1.9 (0.7) and height velocity SDS showed a significant increase from -1.3 (2.0) to 3.7 (1.8) in the first year (p < 0.001) and 1.6 (1.8) (p < 0.01) in the second year of treatment. In the controls, height SDS, initially -2.7 (1.4), and height velocity SDS, initially -0.9 (1.1), remained essentially the same during two years of follow-up. Height SDS for bone age changed by 0.6 in the treated group and 0.4 in the control group. Target height SDS--initial height SDS in the treated group improved by 1.1 SD but declined in the control group. IGF-I levels increased from 9.5 (4.2) nmol/l (72 [31.8] ng/ml) to 32.5 (27.0) nmol/l (244.4 [202.8] ng/ml) (p = 0.004) in the treated group while no change was observed in the controls. No adverse effects were encountered during rhGH therapy. It was concluded that rhGH treatment induces a significant increase in growth velocity in the short term. This outcome, as opposed to the unchanged indices in the control group over the same period, may be indicative of an improved height prognosis in short children born with intrauterine growth retardation treated with rhGH.

Myogenic expression of an injectable protease-resistant growth hormone-releasing hormone augments long-term growth in pigs

Ectopic expression of a new serum protease-resistant porcine growth hormone-releasing hormone, directed by an injectable muscle-specific synthetic promoter plasmid vector (pSP-HV-GHRH), elicits growth in pigs. A single 10 mg intramuscular injection of pSP-HV-GHRH DNA followed by electroporation in three-week-old piglets elevated serum GHRH levels by twofold to fourfold, enhanced growth hormone secretion, and increased serum insulin-like growth factor-I by threefold to sixfold over control pigs. After 65 days the average body weight of the pigs injected with pSP-HV-GHRH was approximately 37% greater than the placebo-injected controls and resulted in a significant reduction in serum urea concentration, indicating a decrease in amino acid catabolism. Evaluation of body composition indicated a uniform increase in mass, with no organomegaly or associated pathology.

Lipid profile, glucose tolerance and insulin sensitivity after more than four years of growth hormone therapy in non-growth hormone deficient adolescents

OBJECTIVE

To study the effects of long-term (> 4 years) growth hormone (GH) therapy on insulin sensitivity, glucose tolerance and lipid profile in non-GH deficient adolescents at completion of their growth.

SUBJECTS

Thirty non-GH deficient (15 'idiopathic' short stature, 8 intrauterine growth retardation, 7 partial GH deficiency in childhood but normal on retesting) were recruited, median (range) age 16.9 years (15-20.3) prior to ceasing their GH therapy. Their median (range) duration of GH treatment was 7.9 years (4-11). Insulin sensitivity was also recorded in 10 normal controls with a median (range) age of 20.5 years (18.4-22.3).

METHODS

Insulin sensitivity was assessed by a short insulin tolerance test in 18 patients on GH therapy and controls. It was repeated in 14 patients six months after stopping their GH therapy. A 3-h standard oral glucose tolerance test (OGTT) was performed in 19 patients on GH therapy, and repeated after 6 months off GH in 10 patients. Fasting lipids were also measured.

RESULTS

Insulin sensitivity index was significantly lower in the patients on GH therapy than in the controls, (median (range)) 3.7%/min (1.2-5.3) and 5.3%/min (3.8-6.2), respectively. Six months after termination of GH therapy, insulin sensitivity increased significantly from 3.6%/min (1.2-5) to 4. 8%/min (2.8-5.6). Fasting plasma insulin decreased significantly off GH therapy from 10.1 to 3.6 mU/l. The area under the insulin curve during the OGTT was also significantly higher on GH therapy. Apart from one patient with impaired glucose tolerance on GH treatment, plasma glucose concentrations remained within the normal range. No lipid abnormalities were recorded.

CONCLUSIONS

These data suggest that long-term GH therapy may cause insulin resistance in non GH deficient adolescents, but usually with neither impaired glucose tolerance nor hyperlipidaemia.

Growth hormone treatment of short children born small for gestational age

Short children born small-for-gestational-age (SGA) appear to be at an increased risk of having a poly-endocrinopathy, including a degree of growth hormone (GH) deficiency and/or insulin-like growth factor 1 (IGF-1) resistance. Among GH-deficient children, those born SGA present a lower growth response to GH therapy than those not born SGA. The growth response of short SGA children to GH treatment does not appear to depend significantly on the secretory status of GH (as judged by provocative testing), indicating that the SGA condition (IGF-1 resistance) predominates over the availability of endogenous GH in determining the short stature of the majority of these children. When a higher than replacement dose of GH is administered, the growth response of short SGA children matches that of GH-deficient non-SGA children, indicating that the IGF-1 resistance towards growth can be overcome, and that a normal stature can be obtained, at least throughout childhood. It is anticipated that, increasingly, the indications and the doses for GH therapy in children will become interlinked with the emerging principles of endocrine programming in early life.