Long-term impact of GH treatment during childhood on body composition and fat distribution in young adults born SGA

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.

Greater insulin resistance in short children born small-for-gestational age than in children with growth hormone deficiency at the early period of growth hormone therapy

BACKGROUND

We compared insulin resistance and glucose metabolism during growth hormone (GH) therapy between 43 short children born small-for-gestational age (SGA) and 42 children identify as growth hormone deficiency (GHD).

METHODS

The study compared fasting plasma glucose (FPG), fasting immunoreactive insulin (IRI) and homeostasis model assessment insulin resistance index (HOMA-IR) during 24-month GH therapy between the two groups.

RESULTS

Mean FPG, fasting IRI, and HOMA-IR values at 3-month GH therapy were significantly higher than those before and at 12- and 24-month GH therapy in both groups. These markers were significantly higher in short children born SGA than GHD children until 12-month GH therapy but were not different at 24-month GH therapy in both groups.

CONCLUSIONS

The increased secretion of insulin observed in short children born SGA might be a compensatory mechanism for the prevention of hyperglycemia that can progress to diabetes mellitus. However, these metabolic markers gradually declined after 3 months of GH therapy and returned to baseline values at 24 months. These results suggest that short children born SGA have greater insulin resistance than GHD children at the early period of GH therapy, however, increased insulin resistance is improved over a long period.

Fat distribution in short-stature children born small for gestational age

BACKGROUND

Children born small for gestational age (SGA) with catch-up growth are at high risk for developing obesity; however, the characteristics of body composition, especially fat distribution, before and after growth hormone (GH) treatment in SGA children without catch-up growth remains largely unknown.

METHODS

Anthropometric characteristics, body composition by dual-energy X-ray absorption, and fat distribution by computed tomography at the umbilical level were examined in 27 prepubertal short-stature children born SGA before and 1 year after GH treatment.

RESULTS

Before GH treatment, short-stature SGA children had lean phenotypes, and both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were significantly lower than the age- and sex-matched Japanese reference values. Growth hormone treatment significantly increased height standard deviation scores (SDS), without affecting body mass index SDS. Percentage fat mass decreased with GH treatment; however, fat mass was not altered. Both VAT and SAT were significantly lower than the reference values after GH treatment. The ratio of VAT over SAT significantly increased by GH treatment.

CONCLUSIONS

Both VAT and SAT were within or below the age- and sex-matched Japanese reference values in short-stature children born SGA before and after GH treatment, indicating that GH treatment may not have unfavorable effects on adiposity in short-stature children born SGA, although it may alter fat distribution.

Evidence for Accelerated Biological Aging in Young Adults with Prader-Willi Syndrome

OBJECTIVE

Adults with Prader-Willi syndrome (PWS) are at increased risk of developing age-associated diseases early in life and, like in premature aging syndromes, aging might be accelerated. We investigated leukocyte telomere length (LTL), a marker of biological age, in young adults with PWS and compared LTL to healthy young adults of similar age. As all young adults with PWS were treated with growth hormone (GH), we also compared LTL in PWS subjects to GH-treated young adults born short for gestational age (SGA).

DESIGN

Cross-sectional study in age-matched young adults; 47 with PWS, 135 healthy, and 75 born SGA.

MEASUREMENTS

LTL measured by quantitative polymerase chain reaction, expressed as telomere/single copy gene ratio.

RESULTS

Median (interquartile range) LTL was 2.6 (2.4-2.8) at a median (interquartile range) age of 19.2 (17.7-21.3) years in PWS, 3.1 (2.9-3.5) in healthy young adults and 3.1 (2.8-3.4) in the SGA group. Median LTL in PWS was significantly lower compared to both control groups (P < .01). In PWS, a lower LTL tended to be associated with a lower total IQ (r = 0.35, P = .08). There was no association between LTL and duration of GH treatment, cumulative GH dose, or several risk factors for type 2 diabetes mellitus or cardiovascular disease.

CONCLUSIONS

Young adults with PWS have significantly shorter median LTL compared to age-matched healthy young adults and GH-treated young adults born SGA. The shorter telomeres might play a role in the premature aging in PWS, independent of GH. Longitudinal research is needed to determine the influence of LTL on aging in PWS.

What is the evidence for beneficial effects of growth hormone treatment beyond height in short children born small for gestational age? A review of published literature

Background An increasing body of evidence supports the view that both an adverse intrauterine milieu and rapid postnatal weight gain in children born small for gestational age (SGA) contribute towards the risk for the development of chronic diseases in adult life. Content The aim of this review was to identify and summarize the published evidence on metabolic and cardiovascular risk, as well as risk of impaired cardiac function, intellectual capacity, quality of life, pubertal development and bone strength among children born SGA. The review will then address whether growth hormone (GH) therapy, commonly prescribed to reduce the height deficit in children born SGA who do not catch up in height, increases or decreases these risks over time. Summary Overall, there are limited data in support of a modest beneficial effect of GH therapy on the adverse metabolic and cardiovascular risk observed in short children born SGA. Evidence to support a positive effect of GH on bone strength and psychosocial outcomes is less convincing. Outlook Further evaluation into the clinical relevance of any potential long-term benefits of GH therapy on metabolic and cardiovascular endpoints is warranted.

Achieving Optimal Short- and Long-term Responses to Paediatric Growth Hormone Therapy

It is over sixty years since the first administration of human growth hormone (GH) to children with GH deficiency, and over thirty years since recombinant human GH has been available for treatment of GH deficiency and a wider range of non-GH deficiency disorders. From a diagnostic perspective, genetic analysis, using single gene or Sanger sequencing and more recently next generation or whole exome sequencing, has brought advances in the diagnosis of specific causes of short stature, which has enabled therapy to be targeted more accurately. Genetic discoveries have ranged from defects of pituitary development and GH action to abnormalities in intracellular mechanisms, paracrine regulation and cartilage matrix formation. The strategy of GH therapy using standard doses has evolved to individualised GH dosing, depending on diagnosis and predictors of growth response. Evidence of efficacy of GH in GH deficiency, Turner syndrome and short children born small for gestational age is reviewed. The importance of critical assessment of growth response is discussed, together with the recognition and management of a poor or unsatisfactory growth response and the organisational issues related to prevention, detection and intervention regarding suboptimal adherence to GH therapy.

Developmental Programming of Body Composition: Update on Evidence and Mechanisms

PURPOSE OF REVIEW

A growing body of epidemiological and experimental data indicate that nutritional or environmental stressors during early development can induce long-term adaptations that increase risk of obesity, diabetes, cardiovascular disease, and other chronic conditions-a phenomenon termed "developmental programming." A common phenotype in humans and animal models is altered body composition, with reduced muscle and bone mass, and increased fat mass. In this review, we summarize the recent literature linking prenatal factors to future body composition and explore contributing mechanisms.

RECENT FINDINGS

Many prenatal exposures, including intrauterine growth restriction, extremes of birth weight, maternal obesity, and maternal diabetes, are associated with increased fat mass, reduced muscle mass, and decreased bone density, with effects reported throughout infancy and childhood, and persisting into middle age. Mechanisms and mediators include maternal diet, breastmilk composition, metabolites, appetite regulation, genetic and epigenetic influences, stem cell commitment and function, and mitochondrial metabolism. Differences in body composition are a common phenotype following disruptions to the prenatal environment, and may contribute to developmental programming of obesity and diabetes risk.

Children Born Small for Gestational Age: Differential Diagnosis, Molecular Genetic Evaluation, and Implications

Children born small for gestational age (SGA), defined as a birth weight and/or length below -2 SD score (SDS), comprise a heterogeneous group. The causes of SGA are multifactorial and include maternal lifestyle and obstetric factors, placental dysfunction, and numerous fetal (epi)genetic abnormalities. Short-term consequences of SGA include increased risks of hypothermia, polycythemia, and hypoglycemia. Although most SGA infants show catch-up growth by 2 years of age, ∼10% remain short. Short children born SGA are amenable to GH treatment, which increases their adult height by on average 1.25 SD. Add-on treatment with a gonadotropin-releasing hormone agonist may be considered in early pubertal children with an expected adult height below -2.5 SDS. A small birth size increases the risk of later neurodevelopmental problems and cardiometabolic diseases. GH treatment does not pose an additional risk.

Metabolic and immunological assessment of small-for-gestational-age children during one-year treatment with growth hormone: the clinical impact of apolipoproteins

Children born small for gestational age (SGA) are at a higher risk for metabolic disorders later in life. In this study, we aimed to characterize young SGA children without catch-up growth and evaluate the effects of GH treatment on endocrinological, metabolic, and immunological parameters. Study design is a one-year single hospital-based study included prospective observation of SGA patients during 12 months of GH treatment. Clinical and laboratory profiles of SGA children at baseline were compared with controls born appropriate size for age. Twenty-six SGA children (median age, 3.4 years) and 26 control children (median age, 3.8 years) were enrolled. Anthropometric, hematologic, biochemical, immunological, and endocrinological parameters were assessed at baseline and 1, 3, 6, 9, and 12 months after the start of GH treatment. As a result, median height SD score (SDS) of SGA children increased by +0.42 with 12-month GH treatment. Body mass index SDS was lower in SGA children than in controls. Serum apolipoprotein A1 increased, whereas apolipoprotein B decreased during GH treatment. Serum leptin and resistin levels, which were lower in SGA children than in controls at baseline, did not change remarkably with GH treatment. Monocyte counts, which were lower in SGA patients at baseline, increased after GH treatment. Neutrophil counts significantly increased after GH treatment. Natural killer cell ratios, which were higher in SGA patients, decreased after GH treatment. In conclusion, there was no evidence suggesting metabolic abnormalities in SGA children. Serum apolipoprotein changes might predict the beneficial role of GH treatment in lowering cardiometabolic risk.

The Rationale for Growth Hormone Therapy in Children with Short Stature

Growth hormone (GH) was first isolated from cadaver pituitary glands, requiring laborious and expensive collection of glands, followed by extraction and purification of the hormone. This limited supply restricted its use to children with severe GH deficiency who were treated with low dosages and suboptimal schedules. The development of recombinant DNA-derived GH, allowed the production of virtually unlimited amounts of GH, leading to the approval for therapy for a large number of childhood conditions characterized by non-GH deficient short stature. The aim of this review is to provide a critical overview on the daily use of GH in two paradigmatic conditions of non-GH deficient short stature which are children born small for gestational age and with idiopathic short stature, highlighting the available strength of evidence for efficacy and safety.

Effects of size at birth, childhood growth patterns and growth hormone treatment on leukocyte telomere length

BACKGROUND

Small size at birth and rapid growth in early life are associated with increased risk of cardiovascular disease in later life. Short children born small for gestational age (SGA) are treated with growth hormone (GH), inducing catch-up in length. Leukocyte telomere length (LTL) is a marker of biological age and shorter LTL is associated with increased risk of cardiovascular disease.

OBJECTIVES

To investigate whether LTL is influenced by birth size, childhood growth and long-term GH treatment.

METHODS

We analyzed LTL in 545 young adults with differences in birth size and childhood growth patterns. Previously GH-treated young adults born SGA (SGA-GH) were compared to untreated short SGA (SGA-S), SGA with spontaneous catch-up to a normal body size (SGA-CU), and appropriate for gestational age with a normal body size (AGA-NS). LTL was measured using a quantitative PCR assay.

RESULTS

We found a positive association between birth length and LTL (p = 0.04), and a trend towards a positive association between birth weight and LTL (p = 0.08), after adjustments for gender, age, gestational age and adult body size. Weight gain during infancy and childhood and fat mass percentage were not associated with LTL. Female gender and gestational age were positively associated with LTL, and smoking negatively. After adjustments for gender, age and gestational age, SGA-GH had a similar LTL as SGA-S (p = 0.11), SGA-CU (p = 0.80), and AGA-NS (p = 0.30).

CONCLUSIONS

Larger size at birth is positively associated with LTL in young adulthood. Growth patterns during infancy and childhood are not associated with LTL. Previously GH-treated young adults born SGA have similar LTL as untreated short SGA, SGA with spontaneous catch-up and AGA born controls, indicating no adverse effects of GH-induced catch-up in height on LTL.

Long-term metabolic risk among children born premature or small for gestational age

Accumulating evidence suggests that both the intrauterine environment and growth during early life can influence the development of chronic noncommunicable diseases, such as type 2 diabetes mellitus and cardiovascular disease, in adulthood. Here, we review the available human data supporting increased metabolic risk among children born premature or small for gestational age; the adrenal and pubertal modifications that contribute to this risk; metabolic changes that occur during adolescence and early adulthood; and approaches to potentially modify or decrease risk of metabolic disease. The risks associated with delivery at term or preterm are compared for each period of life. Knowledge of these associations is fundamental for the paediatric community to develop preventive strategies early during postnatal life.

[Body composition and metabolic risk in small for gestational age children treated with growth hormone]

BACKGROUND AND OBJECTIVES

Small for gestational age (SGA) children are at increased risk of metabolic syndrome. Our objective is to evaluate changes in body composition produced by growth hormone (GH) treatment.

PATIENTS AND METHOD

A group of 28 SGA children without catch-up growth and undergoing treatment with GH was selected for evaluation. Over the course of 3 years from the beginning of the treatment with GH, the children's body composition variables (bone mineral density [BMD], fat and lean body mass proportion) were evaluated annually with dual-energy X-ray absorptiometry. A study of correlation between metabolic and body composition variables was also made.

RESULTS

Treatment with GH produces a reduction in fat mass proportion in relation to lean body mass, decreasing from 25.94±6.09 to 22.88±5.38% (P=.034). In the abdominal regions we observe an increase in lean mass, from 1,356,91±426,71 to 2,570,96±814,36g (P=.000) and a tendency for visceral fat deposits to decrease. BMD in lumbar vertebrae improved from -1.55±0.68 to -0.90±0.79Z (P=.019).

CONCLUSIONS

Treatment with GH produces changes in body composition, improving BMD and increasing the proportion of lean body mass with a reduction in fat mass. If these changes persisted into adulthood, they may cause a reduction in the metabolic and cardiovascular risk in this group of patients.

Growth and Metabolism in Children Born Small for Gestational Age

Most children born SGA show spontaneous catch-up growth to a normal weight and height above -2 SDS; however, 10% remain short. GH treatment improves adult height and has positive effects on body composition, blood pressure and serum lipids. At 6.5 years after stopping GH treatment, body composition, blood pressure, and lipid levels are similar to untreated short SGA adults indicating that GH-induced catch-up in height has no unfavorable effects on metabolic health. GH-induced reduction in insulin sensitivity is reversible after stopping GH. It remains to be elucidated how metabolic health develops when these subjects become older.

Adiposity in Children Born Small for Gestational Age Is Associated With β-Cell Function, Genetic Variants for Insulin Resistance, and Response to Growth Hormone Treatment

BACKGROUND

Genetic susceptibility to insulin resistance is associated with lower adiposity in adults. Insulin resistance, and therefore adiposity, may alter sensitivity to GH. We aimed to determine the relationship between adiposity, genetic susceptibility to insulin resistance or insulin secretion, and response to GH treatment in short children born small for gestational age (SGA).

METHODS

In 89 short prepubertal SGA children (age, 6.2 ± 1.6 y; 55 boys) treated with GH for 1 year in a multicenter study, body fat percentage was estimated at baseline and 1 year using dual-energy x-ray absorptiometry. The main outcome measures were treatment-related changes in height, IGF-1 standard deviation score, insulin sensitivity, insulin secretion, and disposition index. Combined multiallele gene scores based on single nucleotide polymorphisms with known associations with lower insulin sensitivity (gene scores for insulin resistance [GS-InRes]) and insulin secretion (gene scores for insulin secretion [GS-InSec]) were analyzed for their relationships with adiposity.

RESULTS

Mean percentage body fat at baseline was low compared to normative data (P = .045) and decreased even further on GH treatment (baseline vs 1-year z-scores, -0.26 ± 1.2 vs -1.23 ± 1.54; P < .0001). Baseline percentage body fat was positively associated with IGF-1 responses (p-trends = .042), first-year height gains (B [95% confidence interval], 0.61 cm/y [0.28,0.95]; P < .0001), insulin secretion at baseline (p-trends = .020) and 1 year (p-trends = .004), and disposition index at 1 year (p-trends = .024). GS-InRes was inversely associated with body mass index (-0.13 SD score per allele [-0.26, -0.01]; P = .040), body fat (-0.49% per allele [-0.97, -0.007]; P = .047), and limb fat (-0.81% per allele [-1.62, 0.00]; P = .049) at baseline. During GH treatment, GS-InRes was related to a lesser decline in trunk fat (0.38% per allele [0.16, 0.59]; P = .001) and a higher trunk-limb fat ratio at 1 year (0.04 per allele [0.01, 0.08]; P = .008). GS-InSec was positively associated with truncal fat (0.36% per allele [0.09, 0.63]; P = .009).

CONCLUSIONS

Adiposity in SGA children has favorable effects on GH sensitivity and glucose metabolism. The associations with multiallele scores support a causal role of insulin resistance in linking lesser body fat to reduced sensitivity to exogenous GH.