Final height after combined growth hormone and gonadotrophin-releasing hormone analogue therapy in short healthy children entering into normally timed puberty

Magnetic resonance imaging of knees: a novel approach to predict recombinant human growth hormone therapy response in short-stature children in late puberty

BACKGROUND

There is no appropriate tool to predict recombinant human growth hormone (rhGH) response before therapy initiation in short-stature children in late puberty. The current study aimed to explore the associations between magnetic resonance imaging (MRI) stages of the knee growth plates and rhGH response in short-stature children in late puberty.

METHODS

In this prospective cohort study, short-stature children in late puberty were treated with rhGH and followed up for 6 months. We proposed a novel knee MRI staging system according to the growth plate states of distal femurs or proximal tibias and divided the participants into three groups: unclosed growth plate group, marginally closed growth plate group, and nearly closed growth plate group. The primary outcomes were height gain and growth velocity (GV), which were assessed three months later.

RESULTS

Fifty participants were enrolled, including 23 boys and 27 girls. GV and height gain after 6 months of rhGH therapy decreased successively in the three groups with an increased degree of growth plate fusion, especially when grouped by proximal tibias (GV1-3 mon from 9.38 to 6.08 to 4.56 cm/year, GV4-6 mon from 6.75 to 4.92 to 3.25 cm/year, and height gain from 4.03 to 2.75 to 1.95 cm, all P < 0.001). Moreover, the MRI stages of growth plates independently served as a significant variable for GV and height gain after therapy, especially when grouped by proximal tibias (all P < 0.01).

CONCLUSION

The MRI staging method is expected to be an effective tool for predicting rhGH response before therapy initiation in short-stature children in late puberty.

Efficacy and safety of a 4-year combination therapy of growth hormone and gonadotropin-releasing hormone analogue in pubertal girls with short predicted adult height

OBJECTIVES

To improve adult height in pubertal girls with a poor height prediction, treatment with growth hormone (GH) can be used in combination with a gonadotropin releasing hormone agonist (GnRHa), to delay closure of the growth plates. However, there are few studies to support this practice, and they show conflicting results. The objective of this trial is to assess the safety and efficacy of this combination treatment in early pubertal girls with a short predicted height, in comparison with matched controls.

DESIGN PATIENTS AND METHODS

We designed an open-label, multicenter, interventional case-control study. Early pubertal girls with predicted adult height (PAH) below -2.5 SDS, were recruited in tertiary care centers in Belgium. They were treated for four years with GH and GnRHa. The girls were followed until adult height (AH) was reached. AH vs PAH, AH vs Height at start, and AH vs Target Height (TH) were evaluated, as well as safety parameters. Control data were assembled from historical patient files or from patients who preferred not to participate in the study.

RESULTS

Sixteen girls with mean age ( ± SD) at start of 11.0 years (± 1.3) completed the study protocol and follow-up. Their mean height ( ± SD) increased from 131.3 ± 4.1 cm (-2.3 ± 0.7 SDS) at start of treatment to 159.8 ± 4.7 cm (-1.1 ± 0.7 SDS) at AH. In matched controls, height increased from 132.3 ± 4.2 cm (-2.4 ± 0.5 SDS) to 153.2 ± 3.4 cm (-2.1 ± 0.6 SDS) (p<0.001). AH surpassed initial PAH by 12.0 ± 2.6 cm in treated girls; and by 4.2 ± 3.6 cm in the controls (p<0.001). Most treated girls reached normal adult height (>-2SD) (87.5%) and 68.7% reached or superseded the target height (TH), which was the case in only a minority of the controls (37.5% and 6.2%, respectively) (p= 0.003 and 0.001). A serious adverse event possibly related to the treatment, was a fracture of the metatarsals.

CONCLUSION

A four-year GH/GnRHa treatment in early pubertal girls with a poor PAH seems safe and results in a clinically relevant and statistically significant increase in AH compared with matched historical controls.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT00840944.

A meta-analysis of combination therapy with gonadotrophin-releasing hormone agonist and growth hormone for children with idiopathic short stature and normal timed puberty

PURPOSE

The aim of this meta-analysis is to evaluate whether the combination therapy with gonadotrophin-releasing hormone agonist (GnRHa) and recombinant human growth hormone (rhGH) are effective in the treatment of children with idiopathic short stature (ISS) and normal timed puberty by interrogating data from clinical controlled trials.

METHODS

Literature retrieval, trail selection, data abstraction and quality assessment were completed independently by two authors. STATA software (version 14.1) was used for data analyses.

RESULTS

This meta-analysis was conducted based on 8 (4 randomized and 4 non-randomized) controlled trials. A total of 245 ISS children with normal timed puberty were financially analyzed. Overall, combination therapy with GnRHa and rhGH can slightly increase final height by 3.70 and 3.43 cm compared with GH treatment alone and no treatment, final height standard deviation score (FHSDS) by 0.10 and 0.22, final height minus predicted adult height (FH-PAH) by 1.5 and 5.32 cm, final height minus predicted adult height (FH-TH) by 7.70 and 4.32 cm, respectively. Subgroup and meta-regression analyses revealed that study type, sample size, GnRHa duration, and percentage of boys were potential sources of between-trial heterogeneity. There was a low probability of publication bias for above comparisons, as indicated by Egger's tests.

CONCLUSIONS

Our meta-analytical findings indicate that the combination therapy with GnRHa and rhGH can slightly increase the final height of ISS children with normal timed puberty, and the effect was not more obvious than GH alone. We do not recommend the combination therapy as a routine treatment for ISS.

TRIAL REGISTRATION NUMBER

CRD42019133438.

Should Skeletal Maturation Be Manipulated for Extra Height Gain?

Skeletal maturation can be delayed by reducing the exposure to estrogens, either by halting pubertal development through administering a GnRH analogue (GnRHa), or by blocking the conversion of androgens to estrogens through an aromatase inhibitor (AI). These agents have been investigated in children with growth disorders (off-label), either alone or in combination with recombinant human growth hormone (rhGH). GnRHa is effective in attaining a normal adult height (AH) in the treatment of children with central precocious puberty, but its effect in short children with normal timing of puberty is equivocal. If rhGH-treated children with growth hormone deficiency or those who were born small-for-gestational age are still short at pubertal onset, co-treatment with a GnRHa for 2-3 years increases AH. A similar effect was seen by adding rhGH to GnRHa treatment of children with central precocious puberty with a poor AH prediction and by adding rhGH plus GnRHa to children with congenital adrenal hyperplasia with a poor predicted adult height on conventional treatment with gluco- and mineralocorticoids. In girls with idiopathic short stature and relatively early puberty, rhGH plus GnRHa increases AH. Administration of letrozole to boys with constitutional delay of growth puberty may increase AH, and rhGH plus anastrozole may increase AH in boys with growth hormone deficiency or idiopathic short stature, but the lack of data on attained AH and potential selective loss-of-follow-up in several studies precludes firm conclusions. GnRHas appear to have a good overall safety profile, while for aromatase inhibitors conflicting data have been reported.

Combined therapy with GnRH analogue and growth hormone increases adult height in children with short stature and normal pubertal onset

OBJECTIVE

To investigate whether gonadotropin releasing hormone analogue (GnRHa) combined with recombinant human growth hormone (rhGH) can improve the adult height (AHt) of children with short stature and normal pubertal onset.

METHODS

In this retrospective study, GnRHa/rhGH treatment was given to children with normal pubertal onset and short stature. Patients were followed up to measure their AHt. The primary outcomes were the disparity between AHt standard deviation score (AHt SDS) and pre-treatment height standard deviation score (Ht SDS) and the disparity between AHt and target height (THt).

RESULTS

A total of 94 patients were included. Forty-nine boys were treated with GnRHa/rhGH for 24.84 ± 13.01 months, and 45 girls were treated for 23.89 ± 10.43 months. (2) Before treatment, the Ht SDS of boys and girls was -1.82 ± 1.30 and -1.10 ± 1.61, respectively, and the target height was 168.98 ± 3.51 cm and 157.90 ± 3.25 cm, respectively. (3) After treatment, for boys, the AHt SDS increased by 1.37 ± 1.28 (p = 0.000) and the disparity between AHt and THt was 0.98 ± 6.18 cm (p = 0.273); for girls, the AHtSDS increased by 1.28 ± 1.48 (p = 0.000), and the disparity between AHt and THt was 3.64 ± 4.86 cm (n = 45, p = 0.000). (4) Subgroup analysis showed that, for boys with idiopathic short stature (ISS) and non-ISS, AHt SDS increased by 2.00 ± 1.16 (p = 0.000) and 0.71 ± 1.06 (p = 0.003) respectively, compared with the pre-treatment HtSDS; The disparities between AHt and THt were -0.70 ± 6.54 cm and 2.73 ± 5.37 cm respectively. For girls with ISS and non-ISS, AHtSDS increased by 2.73 ± 1.21 (p = 0.000) and 0.748 ± 1.19 (p = 0.001), respectively; AHt increased by 2.63 ± 6.12 cm (p = 0.165) and 4.02 ± 4.37 cm (p = 0.000) compared with THt, respectively. (5) Multiple linear regression analysis showed that the baseline bone age (BA) (β = -0.200, p = 0.003), basal IGF-1(β = -0.002, p = 0.008) and HtSDS (β = -0.679, p = 0.000) had negative effects on increment of AHtSDS.

CONCLUSION

For adolescents with normal pubertal onset and short stature, with or without ISS, GnRHa/rhGH therapy can effectively improve AHtSDS. After treatment, ISS adolescents can reach the THts, and Non-ISS adolescents can exceed their THts.

Use of Gonadotropin-Releasing Hormone Analogs in Children: Update by an International Consortium

This update, written by authors designated by multiple pediatric endocrinology societies (see List of Participating Societies) from around the globe, concisely addresses topics related to changes in GnRHa usage in children and adolescents over the last decade. Topics related to the use of GnRHa in precocious puberty include diagnostic criteria, globally available formulations, considerations of benefit of treatment, monitoring of therapy, adverse events, and long-term outcome data. Additional sections review use in transgender individuals and other pediatric endocrine related conditions. Although there have been many significant changes in GnRHa usage, there is a definite paucity of evidence-based publications to support them. Therefore, this paper is explicitly not intended to evaluate what is recommended in terms of the best use of GnRHa, based on evidence and expert opinion, but rather to describe how these drugs are used, irrespective of any qualitative evaluation. Thus, this paper should be considered a narrative review on GnRHa utilization in precocious puberty and other clinical situations. These changes are reviewed not only to point out deficiencies in the literature but also to stimulate future studies and publications in this area.

The Beneficial Effect of Combined GH/GnRHa Therapy in Increasing Adult Height Outcome in Children With ISS

CONTEXT

Management of GH-treated children with idiopathic short stature (ISS) with early puberty and adolescents in midpuberty at initiation of treatment is challenging.

OBJECTIVE

To assess the effect of combined GH/GnRHa therapy during puberty on achieved adult height (AHt) in these children with ISS and to determine whether outcome depended on sex and pubertal status at initiation of GH therapy.

DESIGN

Retrospective, single-center observational study from 2003-2018.

SETTING

Tertiary endocrine center.

PATIENTS

One hundred ninety-two GH-treated children with ISS; 58 of 192 were treated by GH/GnRHa during puberty; 31 of 58 were prepubertal (19 girls) and 27 of 58 pubertal (19 girls) at initiation of GH.

MAIN OUTCOME MEASURES

AHt, gain-in-height standard deviation score (SDS), AHt vs predicted adult height (PAHt), AHt vs target height (THt).

RESULTS

Most boys and girls attained AHt SDS within the normal range (-0.73 ± 0.60 and -0.85 ± 0.65, respectively). Treatment modality, pubertal status, and sex were tested for their joint effect on growth outcome measures. Combined GH/GnRHa therapy increased AHt vs PAHt (P < 0.001) and AHt vs THt (P = 0.035). Prepubertal status at onset of GH treatment increased AHt (P = 0.049), gain-in-height SDS (P < 0.001), AHt vs PAHt (P < 0.001), and AHt vs THt (P = 0.042). Female sex increased AHt vs PAHt (P < 0.001).

CONCLUSIONS

Our study demonstrated a beneficial effect of combined GH/GnRHa therapy in increasing AHt outcome in children with ISS with early/normal puberty and in adolescents naïve to GH treatment who are in midpuberty at initiation of therapy. This effect was more pronounced in the prepubertal group and in girls. Prospective randomized controlled trials are needed to assess whether GnRHa can increase AHt in GH-treated children with ISS.

Postnatal management of growth failure in children born small for gestational age

OBJECTIVES

To discuss the etiology and growth consequences of small size at birth and the indications, effects, and safety of biosynthetic growth hormone therapy in children born small for gestational age.

SOURCE OF DATA

A comprehensive and non-systematic search was carried out in the PubMed, LILACS, and SciELO databases from 1980 to the present day, using the terms "small for gestational age," "intrauterine growth restriction," and "growth hormone". The publications were critically selected by the authors.

DATA SYNTHESIS

Although the majority of children born small for gestational age show spontaneous catch-up growth during the first two years of life, some of them remain with short stature during childhood, with high risk of short stature in adult life. Treatment with growth hormone might be indicated, preferably after 2-4 years of age, in those small for gestational age children who remain short, without catch-up growth. Treatment aims to increase growth velocity and to reach a normal height during childhood and an adult height within target height. Response to growth hormone treatment is variable, with better growth response during the pre-pubertal period.

CONCLUSIONS

Treatment with growth hormone in short children born small for gestational age is safe and effective to improve adult height. Efforts should be done to identify the etiology of small size at birth before treatment.

Is a Combination of a GnRH Agonist and Recombinant Growth Hormone an Effective Treatment to Increase the Final Adult Height of Girls with Precocious or Early Puberty?

The aim of treatment for idiopathic central precocious puberty (ICPP) is to increase final adult stature, for which gonadotropin-releasing hormone agonist (GnRHa) is the gold standard. Early puberty is frequently similar to ICPP, with pubertal onset only slightly advanced. Short stature may result from early pubertal onset. Some studies have suggested that recombinant human growth hormone (rhGH) should be combined with a GnRHa to improve adult height, while others have not. Here, the aim was to compare the efficacy of combined GnRHa and rhGH treatment with GnRHa or rhGH treatment alone, or no therapy, for the improvement of the final height of girls with ICPP or early puberty. Electronic databases of randomized and quasi-randomized controlled trials, in which the efficacy of GnRHa preparations was compared with that of rhGH for the treatment of children with precocious or early puberty, were searched and a meta-analysis conducted. Five studies of early puberty and four studies of ICPP were identified. There were no statistically significant differences between final adult height standard deviation score and initial height standard deviation score in the treatment of early puberty (GnRHa and rhGH versus rhGH alone or no treatment). The overall analysis of the data failed to indicate any benefit of combined therapy, while individual reports suggested that in specific instances combined therapy may be beneficial in preserving or reclaiming growth potential and improving adult height.

A Critical Appraisal of the Effect of Gonadotropin-Releasing Hormon Analog Treatment on Adult Height of Girls with Central Precocious Puberty

Central precocious puberty (CPP) is a diagnosis that pediatric endocrinologists worldwide increasingly make in girls of age 6-8 years and is mostly idiopathic. Part of the reason for increasing referral and diagnosis is the perception among the doctors as well as the patients that treatment of CPP with long-acting gonadotropin-releasing hormon analogues (GnRHa) promote height of the child. Although, the timing and the tempo of puberty does influence statural growth and achieved adult height, the extent of this effect is variable depending on several factors and is modest in most cases. Studies investigating GnRHa treatment in girls with idiopathic CPP demonstrate that treatment is able to restore adult height compromised by precocious puberty. However, reports on untreated girls with precocious puberty demonstrate that some of these girls achieve their target height without treatment as well, thus, blurring the net effect of GnRHa treatment on height in girls with CPP. Clinical studies on treatment of girls with idiopathic CPP on adult stature suffers from the solid evidence-base due mainly to the lack of well-designed randomized controlled studies and our insufficiencies of predicting adult height of a child with narrow precision. This is particularly true for girls in whom age of pubertal onset is close to physiological age of puberty, which are the majority of cases treated with GnRHa nowadays. Heterogeneous nature of pubertal tempo (progressive vs. nonprogressive) leading to different height outcomes also complicates the interpretation of the results in both treated and untreated cases. This review will attemp to summarize and critically appraise available data in the field.

Aromatase inhibitors for short stature in male children and adolescents

BACKGROUND

As a result of the essential role of oestrogens in epiphyseal closure, aromatase inhibitors have been trialled as an intervention to improve height outcomes in male children and adolescents by inhibiting the conversion of testosterone to oestradiol.

OBJECTIVES

To assess the effects of aromatase inhibitors in male children and adolescents with short stature.

SEARCH METHODS

To identify relevant trials, we searched the Cochrane Library (2014, Issue 7), MEDLINE, EMBASE, and the World Health Organization (WHO) ICTRP trial register from their inception until August 2014. In addition, we conducted citation searches and screened reference lists of included trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) if they compared use of an aromatase inhibitor with placebo in male children and adolescents with short stature.

DATA COLLECTION AND ANALYSIS

Two authors independently screened titles and abstracts for relevance. Both authors carried out screening for inclusion, data extraction, and risk of bias assessment, with any disagreements resolved following discussion. We assessed trials for quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) instrument. We contacted study authors regarding missing information. Primary outcomes were final or near-final height, adverse events, and health-related quality of life. Secondary outcomes included all-cause mortality, cognitive outcomes, socioeconomic effects, laboratory measures, short-term growth parameters, and assessment of effects on bone health. Meta-analysis was not appropriate due to the substantial clinical heterogeneity between trials; we presented the findings of the review in narrative format.

MAIN RESULTS

We included four RCTs involving 207 participants (84 on interventions) in the review. Trials included males with constitutional delay of growth and puberty (CDGP), idiopathic short stature (ISS), and growth hormone (GH) deficiency. Three of the trials had an overall low or unclear risk of bias for primary outcomes. Short-term growth outcomes, such as predicted adult height, improved in all trials. Just one trial reported the primary outcome of final and near-final height as an extension under non-randomised conditions. None of the trials assessed health-related quality of life. One publication provided detailed information regarding the incidence of adverse events. A significant proportion (45%) of prepubertal boys with ISS treated with letrozole developed mild morphological abnormalities of their vertebrae, compared with none in the placebo group.

AUTHORS' CONCLUSIONS

Available evidence suggested that aromatase inhibitors improved short-term growth outcomes. There was no evidence to support an increase in final adult height, based on limited data, with only one of four trials publishing final height data under non-randomised conditions.

Novel approaches to short stature therapy

Besides growth hormone, several pharmaceutical products have been investigated for efficacy and safety in increasing short term growth or adult height. Short-term treatment with testosterone esters in boys with constitutional delay of growth and puberty is efficacious in generating secondary sex characteristics and growth acceleration. The addition of oxandrolone to growth hormone (GH) in Turner syndrome has an additive effect on adult height gain. Treatment with GnRH analogs is the established treatment of central precocious puberty, and its addition to GH therapy appears effective in increasing adult height in GH deficient children, and possibly short children born SGA or with SHOX deficiency, who are still short at pubertal onset. Aromatase inhibitors appear effective in several rare disorders, but their value in increasing adult height in early pubertal boys with GH deficiency or idiopathic short stature is uncertain. A trial with a C-natriuretic peptide analog offers hope for children with achondroplasia.

Initiating growth hormone therapy for children and adolescents

It is common for children and adolescents on growth hormone (GH) treatment to miss one or more injections per week, thereby compromising their linear growth outcome. Among factors likely to affect treatment concordance are patient education and support in the selection of the most appropriate GH injection device. The authors discovered inconsistencies in the process of starting patients on GH therapy throughout the UK, and found that there were no clinical recommendations to support health professionals starting patients on treatment. This article describes the issues involved and the development of practical recommendations for use when starting paediatric patients on long-term GH therapy.

Pubertal disorders and bone maturation

Bone age (BA) indicates more clearly than chronologic age how far an individual has progressed toward full maturity, and predicts the potential for further growth. Single or serial skeletal age estimations help to confirm the diagnosis of normal puberty and normal pubertal variants such as constitutional delay of growth and puberty, premature therlache, and precocious adrenarche. BA can aid in the clinical workup of children whose sexual maturation is early or delayed. Although BA is considered a qualitative rather than quantitative measure, it serves to round out the clinical picture, providing information without which diagnosis could not be achieved.

Combined Treatment with Gonadotropin-releasing Hormone Analog and Anabolic Steroid Hormone Increased Pubertal Height Gain and Adult Height in Boys with Early Puberty for Height

Twenty-one boys with a height of 135 cm or less at onset of puberty were treated with a combination of GnRH analog and anabolic steroid hormone, and their pubertal height gain and adult height were compared with those of untreated 29 boys who enter puberty below 135 cm. The mean age at the start of treatment with a GnRH analog, leuprorelin acetate depot (Leuplin^®) was 12.3 yr, a mean of 1.3 yr after the onset of puberty, and GnRH analog was administered every 3 to 5 wk thereafter for a mean duration of 4.1 yr. The anabolic steroid hormone was started approximately 1 yr after initiation of treatment with the GnRH analog. The mean pubertal height gain from onset of puberty till adult height was significantly greater in the combination treatment group (33.9 cm) than in the untreated group (26.4 cm) (p<0.0001). The mean adult height was significantly greater in the combination treatment group (164.3 cm) than in the untreated group (156.9 cm) (p<0.0001). The percentage of subjects with an adult height of 160 cm or taller was 90.5% (19/21) in the combination treatment group, and it was 13.8% (4/29) in the untreated group (p<0.0001). Since growth of the penis and pubic hair is promoted by the anabolic steroid hormone, no psychosocial problems arose because of delayed puberty. No clinically significant adverse events appeared. Combined treatment with GnRH analog and anabolic steroid hormone significantly increased height gain during puberty and adult height in boys who entered puberty with a short stature, since the period until epiphyseal closure was extended due to deceleration of the bone age maturation by administration of the GnRH analog and the growth rate at this time was maintained by the anabolic steroid hormone.

Strategies for maximizing growth in puberty in children with short stature

The approach to the child with growth retardation who is in puberty remains an important clinical challenge. The use of high-dose growth hormone (GH), suppression of puberty with GnRH analogs in combination with GH, and the use of selective inhibitors of the aromatase enzyme with aromatase inhibitors (also in combination with GH) are all therapeutic choices that have been studied. Aromatase blockade effectively blocks estrogen production in males with a reciprocal increase in testosterone, and a new generation of aromatase inhibitors, including anastrozole, letrozole and exemestane, is under investigation in adolescent subjects with severe growth retardation. This class of drugs, if judiciously used for a window of time, offers promise as an adjunct treatment of growth delay in pubertal patients with GH deficiency, idiopathic short stature, testotoxicosis, and other disorders of growth. These evolving uses of aromatase inhibitors, however, represent off-label use of the product, and definitive data on their efficacy are not available for each of the conditions mentioned. Safety issues regarding bone health also require further study.

Strategies for maximizing growth in puberty in children with short stature

The approach to the child with growth retardation who is in puberty remains an important clinical challenge. The use of high-dose growth hormone (GH), suppression of puberty with GnRH analogs in combination with GH, and the use of selective inhibitors of the aromatase enzyme with aromatase inhibitors (also in combination with GH) are all therapeutic choices that have been studied. Aromatase blockade effectively blocks estrogen production in males with a reciprocal increase in testosterone, and a new generation of aromatase inhibitors, including anastrozole, letrozole and exemestane, is under investigation in adolescent subjects with severe growth retardation. This class of drugs, if judiciously used for a window of time, offers promise as an adjunct treatment of growth delay in pubertal patients with GH deficiency, idiopathic short stature, testotoxicosis, and other disorders of growth. These evolving uses of aromatase inhibitors, however, represent off-label use of the product, and definitive data on their efficacy are not available for each of the conditions mentioned. Safety issues regarding bone health also require further study.

Idiopathic short stature: management and growth hormone treatment

In the management of ISS auxological, biochemical, psychosocial and ethical elements have to be considered. In boys with constitutional delay of growth and puberty androgens are effective in increasing height and sexual characteristics, but adult height is unchanged. GH therapy is efficacious in increasing height velocity and adult height, but the inter-individual variation is considerable. The effect on psychosocial status is uncertain. Factors affecting final height gain include GH dose, height deficit in comparison to midparental height, age and first year height velocity. In case of a low predicted adult height at the onset of puberty, addition of a GnRH analogue can be considered. Although GH therapy appears safe, long-term monitoring is recommended.

Anastrozole increases predicted adult height of short adolescent males treated with growth hormone: a randomized, placebo-controlled, multicenter trial for one to three years

CONTEXT

The process of epiphyseal fusion during puberty is regulated by estrogen, even in males.

OBJECTIVE

Our objective was to investigate whether anastrozole, a potent aromatase inhibitor, could delay bone age acceleration and increase predicted adult height in adolescent boys with GH deficiency.

METHODS

Fifty-two adolescent males with GH deficiency treated with GH were randomized to cotreatment with anastrozole or placebo daily for up to 36 months.

RESULTS

Fifty subjects completed 12 months, 41 completed 24 months, and 28 completed 36 months. Linear growth was comparable between groups; however, there was a significantly slower increase in bone age advancement from baseline in the anastrozole group vs. placebo group after 2 yr (+1.8+/-0.1 vs. +2.7+/-0.1 yr, P<0.0001) and after 3 yr (+2.5+/-0.2 vs. +4.1+/-0.1 yr, P<0.0001). This resulted in a net increase in predicted adult height of +4.5+/-1.2 cm in the anastrozole group at 24 months and +6.7+/-1.4 cm at 36 months as compared with a 1-cm gain at both time points in the placebo group. Estradiol and estrone concentrations increased less in the anastrozole group compared with placebo group. All boys on the aromatase inhibitor had normal tempo of virilization. Safety data, including glucose, and plasma lipid concentrations were comparable between groups.

CONCLUSIONS

Anastrozole increases adult height potential of adolescent boys on GH therapy while maintaining normal pubertal progression after 2-3 yr. This treatment offers an alternative in promoting growth in GH-deficient boys in puberty. Long-term follow up is needed to elucidate fully the safety and efficacy of this approach.

Final height outcome after three years of growth hormone and gonadotropin-releasing hormone agonist treatment in short adolescents with relatively early puberty

OBJECTIVE

Our objective was to assess final height (FH) and adverse effects of combined GH and GnRH agonist (GnRHa) treatment in short adolescents born small for gestational age or with normal birth size (idiopathic short stature).

DESIGN AND PATIENTS

Thirty-two adolescents with Tanner stage 2-3, age and bone age (BA) less than 12 yr for girls or less than 13 yr for boys, height sd score (SDS) less than -2.0 SDS or between -1.0 and -2.0 SDS plus a predicted adult height (PAH0) less than -2.0 SDS were randomly allocated to receive GH plus GnRHa (n=17) or no treatment (n=15) for 3 yr. FH was assessed at the age of 18 yr or older in girls or 19 yr or older in boys.

RESULTS

FH was not different between treatment and control groups. Treated children had a larger height gain (FH-PAH0) than controls: 4.4 (4.9) and -0.5 (6.4) cm, respectively (P<0.05). FH was higher than PAH0 in 76 and 60% of treated and control subjects, respectively. During follow-up, 50% of the predicted height gain at treatment withdrawal was lost, resulting in a mean gain of 4.9 cm (range, -4.0 to 12.3 cm) compared with controls. Treatment did not affect body mass index or hip bone mineral density. Mean lumbar spine bone mineral density and bone mineral apparent density tended to be lower in treated boys, albeit statistically not significant.

CONCLUSION

Given the expensive and intensive treatment regimen, its modest height gain results, and the possible adverse effect on peak bone mineralization in males, GH plus GnRHa cannot be considered routine treatment for children with idiopathic short stature or persistent short stature after being born small for gestational age.

Adult height in patients with permanent growth hormone deficiency with and without multiple pituitary hormone deficiencies

CONTEXT

It has been reported that patients with multiple pituitary hormone deficiencies (MPHDs) achieve a greater final height, compared with patients with isolated GH deficiency (IGHD). However, the outcome of patients with permanent GH deficiency (GHD) has not yet been reported.

OBJECTIVES

The objectives of the study were to evaluate and compare adult height data and the effect of spontaneous or induced puberty after long-term treatment with GH in young adults with either permanent IGHD or MPHD.

DESIGN AND SETTING

This was a retrospective multicenter study conducted in university research hospitals and a tertiary referral endocrine unit.

PATIENTS AND METHODS

Thirty-nine patients with IGHD (26 males, 13 females) and 49 with MPHD (31 males, 18 females), diagnosed at a median age of 7.7 and 6.9 yr, respectively, were reevaluated for GH secretion after adult height achievement (median age 17.6 and 19.8 yr). The diagnosis of permanent GHD was based on peak GH levels less than 3 microg/liter after an insulin tolerance test or peak GH levels less than 5 microg/liter after two different tests. Fifteen subjects had idiopathic GHD and seventy-three had magnetic resonance imaging evidence of congenital hypothalamic-pituitary abnormalities. Height sd score (SDS) was analyzed at diagnosis, the onset of puberty (either spontaneous or induced), and the time of GH withdrawal.

RESULTS

The subjects with IGHD entered puberty at a median age of 12.6 yr (females) and 13.4 yr (males). Puberty was induced at a median age of 13.5 and 14.0 yr, respectively, in males and females with MPHD. Median height SDS at the beginning of puberty was similar in the IGHD and MPHD subjects. Total pubertal height gain was similar between patients with IGHD or MPHD. Median adult height was also not significantly different between IGHD and MPHD patients (males, 168.5 vs. 170.3 cm; females, 160.0 vs. 157.3 cm). The adult height SDS of the IGHD subjects was positively correlated with height at the time of diagnosis and with total pubertal height gain. Conversely, the adult height SDS of the MPHD subjects was positively correlated with both the duration of GH treatment and height SDS at the time of GHD diagnosis.

CONCLUSIONS

Adult height in patients with permanent IGHD and spontaneous puberty is similar to adult height in patients with MPHD and induced puberty.

Management of short stature with GnRH agonist and co-treatment with growth hormone: a controversial issue

Adolescent growth is the focus of several interventions aimed at increasing the amplitude of the adolescent spurt. Favorable results with GnRH agonists in precocious puberty have encouraged attempts to increase the duration of the adolescent growth spurt by delaying normal puberty in short individuals using GnRH agonists with or without growth hormone. These approaches remain highly controversial, have not been validated and approved for use by regulatory authorities and were the topic of a session at the 6th International Conference on the Onset of Puberty. Here we review the available information on the efficacy and safety of this approach. GnRH agonists, when used outside the context of precocious puberty, induce a modest gain when used for extended periods of time. Several trials have now shown that growth hormone alone can modestly increase adult height in short adolescents with idiopathic short stature or in those born small for gestational age. The association of growth hormone and GnRH agonists still lacks a definite demonstration of its additional efficacy and available results do not allow firm conclusions. In conclusion, watchful waiting or sex steroids in delayed puberty are generally the best options in short children presenting around puberty. However, long-term and adequately powered clinical trials, focusing on efficacy, safety and clinical significance are needed to fully evaluate the combination of growth hormone and GnRH agonists in short adolescents. In the meanwhile, these approaches should be considered as experimental.

Combined use of growth hormone and gonadotropin-releasing hormone analogue in short normal adolescent girls: a survey from Iran

Combined therapy with gonadotropin-releasing hormone (GnRH) analogue and growth hormone (GH) has been used to increase the height of adolescents who are not GH deficient and who have normally timed puberty. Its use, however, is still controversial. For 2 years simultaneously, we treated eight healthy girls with very low predicted adult height (PAH < 145 cm) who were entering into normally timed puberty. The GnRH analogue triptorelin pamoate (Decapeptyl, 100 microg/kg intramuscularly every 4 weeks) and GH (0.1 IU/kg/day subcutaneously, 6 days/week) were administered. The mean chronologic age (CA) of our patients was 11.01 +/- 0.95 years, and mean bone age (BA) was 12.25 +/- 1.13 years. With a height of 131.50 +/- 5.83 cm (-2.37 +/- 0.35 SD below the mean) and PAH of 140.87 +/- 3.53 cm, they were all in Tanner stage 2-3 of puberty (except one patient in stage 4). In all cases, GH and thyroid hormone deficiency were ruled out before the study began. Height and BA were measured immediately after discontinuation of therapy. PAH was determined before and at the end of therapy. Combined treatment resulted in a 4.13 +/- 1.19 cm increase in PAH (p < 0.01). Height increased significantly to 142.66 +/- 3.54 cm at the end of treatment (p < 0.01). Height standard deviation score for CA increased from -2.37 +/- 0.35 to -2.32 +/- 0.67, showing no significant improvement (p = 0.5). Height age (HA)/BA ratio and BA/CA ratio both demonstrated significant growth during the treatment (p < 0.03 and p < 0.01, respectively), whereas HA/CA ratio did not improve significantly (p < 0.32). During treatment, puberty was completely suppressed in all cases. Combination therapy with GnRH analogue and GH resulted in significant improvement in height and PAH during therapy. Additional, and perhaps more long-term, studies are required to show whether this kind of treatment is effective in improving final adult height. The cost-benefit of such therapies should also be taken into account.

Psychosocial Functioning of Adolescents with Idiopathic Short Stature or Persistent Short Stature Born Small for Gestational Age during Three Years of Combined Growth Hormone and Gonadotropin-Releasing Hormone Agonist Treatment

AIM

To examine psychosocial functioning of medically referred adolescents with idiopathic short stature (ISS) or persistent short stature born small for gestational age (SGA) during 3 years of combined growth hormone (GH) and gonadotropin-releasing hormone agonist (GnRHa) treatment.

METHODS

Thirty-eight adolescents participated in a controlled trial with GH/GnRHa treatment or no intervention. Each year the adolescents and their parents completed questionnaires and structured interviews. Multilevel analysis was used to analyze data.

RESULTS

The adolescents of the treatment group showed a worse outcome than the adolescents of the control group on 3 of 16 variables: perceived competence of scholastic (p < 0.01) and athletic ability (p < 0.05) and trait anxiety (p < 0.05). Adolescents in both the treatment and control groups perceived improved current height (p < 0.001) and self-appraisal of physical appearance (p < 0.05). The parents did not report changes in their children during treatment.

CONCLUSION

The observation of some adverse psychological consequences as experienced by the adolescents indicates that it is useful to monitor psychosocial functioning during a combined GH/GnRHa treatment in adolescents with ISS or SGA. It is uncertain whether the hypothesized positive effects of the expected gain in final height by adulthood can sufficiently counterbalance possible short-term negative effects.

Final height after treatment of early puberty in short adopted girls with gonadotrophin releasing hormone agonist with or without growth hormone

OBJECTIVE

To compare final height data after treatment with gonadotrophin releasing hormone agonist (GnRHa) alone or in combination with growth hormone (GH) in short adopted girls with early puberty.

DESIGN

A randomized controlled trial.

PATIENTS AND METHODS

Twenty-six girls with onset of puberty before 10 years of age were treated for 3 years with either GnRHa alone (group A, n = 12) or with GnRHa and GH (group B, n = 14). Mean age at start of treatment was 9.6 years in both groups, bone age was 10.7 (SD 1.1) years in group A and 11.6 (0.8) years in group B.

RESULTS

Initial height prediction with average Bayley & Pinneau tables was 149.8 (5.6) and 146.8 (4.8) cm, respectively. Bone age at discontinuation of treatment was 12.3 (0.9) and 13.0 (0.6) years in group A and B, respectively. Height gain defined as the difference between initial height prediction and attained final height, was significantly different between group A and B (5.2 (3.7) and 8.2 (3.4) cm, P < 0.05) using average tables for height prediction. With accelerated tables for prediction the numbers were -1.0 (3.6) and 3.3 (3.5) cm, respectively. At final height, there was no significant difference in height: group A: 155.0 (5.6) cm and group B: 155.0 (5.5) cm.

CONCLUSIONS

After 3 years of GnRHa treatment in adopted girls with early puberty, FH is significantly higher than initial height prediction. The addition of GH resulted in a limited further increase in height gain. In the interpretation of the results methodological issues concerning height prediction have to be taken into account.

Long-term outcome of growth hormone therapy in children and adolescents

Growth hormone (GH) has been available for more than 4 decades for the treatment of GH deficiency. Initially, GH was extracted from the pituitary glands of human cadavers, but its use was discontinued following the transmission of the Creutzfeldt-Jakob virus. After the development of recombinant GH (somatropin) in 1985, an 'unlimited' commercial source of GH has been available, allowing for the treatment of a large number of short GH-deficient and -sufficient children. Refinements in both the dosage and the frequency of administration of GH have allowed GH-deficient children to reach nearly normal final heights, although mostly they are still below their target heights. Decreased bone mineral densities and increased concentrations of fasting and postprandial lipids, coagulation factors, and several independent cardiovascular risk factors have been reported in GH-deficient children and adolescents and appear to improve with GH administration. The short-term administration of GH to mostly non-GH-deficient short children with Turner syndrome, chronic renal insufficiency (CRI), intrauterine growth retardation (IUGR), and idiopathic short stature (ISS) has resulted in increased growth velocities. In addition, the final height of patients with Turner syndrome and CRI appears to improve with the long-term administration of GH. Final height data are still lacking in adolescents with IUGR, but height standard deviation score and final height predictions appear to improve with therapy. Based on the incomplete and inconclusive available data, one must conclude that GH treatment of children with ISS cannot be advised. The use of GH at replacement doses in children with GH deficiency has resulted in rare and generally reversible adverse effects. The long-term administration of pharmacologic GH doses to short, mostly non-GH-deficient children must, however, still be viewed with caution, as long-term complications cannot as yet be fully evaluated. GH therapy must be individualized and should be limited only to children with severe short stature or a significantly decreased growth velocity, to children under considerable stress due to their short stature, and to patients in whom low GH or low insulin-like growth factor-1 secretion might be the rate-limiting factors for growth. The cost of the medication and the inconvenience of daily GH injections to otherwise mostly healthy short children must also be taken into account.

Growth hormone treatment in non-growth hormone-deficient short children

The unlimited availability of GH obtained by recombinant DNA technology has allowed optimization of treatment in GH-deficient (GHD) children. At the same time it has prompted a number of studies in conditions not characterized by GHD such as Turner syndrome, intrauterine growth retardation, chronic renal failure and other chromosomal and genetic abnormalities associated with short stature. Several controlled and uncontrolled studies have now reported the adult height of patients with short stature and normal GH secretion. Critical reviewing of the data shows that some short non-GHD children may benefit from a prolonged treatment with GH. However, further studies are needed in order to be able to identify the subjects for whom treatment is really beneficial.

Letrozole significantly improves growth potential in a pubertal boy with growth hormone deficiency

Clinical experience with using an aromatase inhibitor to suppress estrogen production during puberty for improvement of growth potential in adolescents with short stature is limited. This report documents treatment of such a patient with a combination of growth hormone and letrozole, a third-generation aromatase inhibitor. Our case demonstrates a favorable outcome on a short-term basis.

An open label 12-month pilot trial on the effects of the aromatase inhibitor anastrozole in growth hormone (GH)-treated GH deficient adolescent boys

OBJECTIVE

To investigate whether 12 mo treatment with the aromatase inhibitor anastrozole can achieve sustained suppression of estrogen production and delay epiphyseal fusion in growth hormone deficient (GHD) adolescent males.

STUDY DESIGN

20 adolescents with GHD were recruited (mean age +/- SE: 14.7 +/- 0.5 yr). Ten continued on GH (control group), and 10 on GH and anastrozole (Rx group) for 12 mo.

RESULTS

After 12 mo E2 concentrations declined 60% in the Rx group (from 1.8 +/- 0.5 to 0.7 +/- 0.3 pg/ml, p <0.05) whereas they increased in controls (from 1.2 +/- 0.7 to 1.8 +/- 0.7, p <0.05). Testosterone increased 117% in the Rx group (from 304 +/- 31 to 626 +/- 64 ng/dl), 47% in controls (from 274 +/- 89 to 398 +/- 51) (p = 0.03, ANOVA between groups). IGF-I increased 42% in controls (454 +/- 22 to 711 +/- 109 ng/ml, p <0.05), but remained invariant in the Rx group (446 +/- 29 to 540 +/- 80, p = NS). Bone markers, plasma lipids, insulin, glucose, and liver function tests were all unchanged between groups with no differences either in body composition or bone mineral density accrual. There were no differences in growth velocity, height SDS, bone age advancement, predicted adult height or testicular volumes between groups after 12 mo.

CONCLUSIONS

Anastrozole treatment potently decreases estrogen concentrations in adolescent males with GHD while allowing normal virilization, without deleterious effects on body composition, plasma lipids, bone metabolism or the tempo of puberty. Twelve months of treatment, however, did not increase predicted adult height. Further studies are needed to ascertain whether more prolonged estrogen blockade is helpful in the treatment of growth retardation in puberty.

Accelerated versus slowly progressive forms of puberty in girls with precocious and early puberty. Gonadotropin suppressive effect and final height obtained with two different analogs

OBJECTIVES

To distinguish which children with precocious puberty (PP) and early puberty (EP) should be treated and which followed without therapy. To determine the effect of GnRH analog treatment on the final height of treated patients and compare the effect of two different analogs on gonadotropin suppression and final height.

STUDY DESIGN

Sixteen females with PP or EP with a mean chronological age (CA) of 8.8 +/- 1.4 years and a mean bone age (BA) of 10.8 +/- 1.3 years were treated for a mean of 2.7 +/- 1.0 years with a GnRH analog (triptorelin or leuprolide acetate; group A), while 21 girls with a mean CA of 8.5 +/- 1.0 years, a mean BA of 9.7 +/- 1.4 years and a predicted adult height of >155 cm were followed without therapy (group B). Criteria for treatment were one of: a. predicted adult height (PAH) of <155 cm initially or at any time during follow up; b. PAH over 155 cm with a dramatic decrease in PAH over a 6-month follow-up period; c. advanced and rapidly progressing breast development for age (Tanner 3 before the age of 9 years).

RESULTS

GnRHa therapy suppressed gonadotropins in group A, while gonadotropins increased gradually in group B. Height velocity (HV) decreased in group A, while it remained accelerated in group B; BA increased a mean of 1.7 +/- 0.5 years in group A and 3.2 +/- 0.3 years in group B. This resulted in a height increase in group A from a baseline PAH of 153.7 +/- 1.2 cm to a final height (FH) of 160.9 +/- 4.0 cm (p <0.001), clearly above their target height (TH) of 157.7 +/- 4.2 cm. The height of group B children did not change over time (164.1 +/- 4.1 cm before therapy and 166.0 +/- 6.0 cm at FH), both above their TH. The mean leuprolide acetate dose utilized in this study decreased during treatment, while both the initial and final triptorelin dose remained unchanged. Adequate gonadotropin suppression (peak level of LH and FSH of <2 IU/l after i.v. GnRH stimulation) was noted with both leuprolide acetate and triptorelin, although LH suppression was slightly more pronounced with triptorelin. BA advanced 1.8 +/- 0.4 years during leuprolide acetate treatment and 1.5 +/- 0.3 years with triptorelin, so that FH increased a mean of 5.5 +/- 1.3 cm with leuprolide acetate and 8.7 +/- 2.2 cm with triptorelin.

CONCLUSIONS

PAH of <155 cm before or during therapy, PAH of >155 cm with a dramatic decrease in predicted height over a 6-month follow-up period and/or advanced and rapidly progressing breast development in girls with PP or EP were useful parameters in deciding which patients to treat. GnRHa therapy suppressed gonadotropins, HV and bone maturation in children with an accelerated form of PP or EP, resulting in a significant height increase. Final height remained stable over time in untreated patients. Adequate gonadotropin suppression was noted with both analogs, although with the doses of analog used in our study, LH and BA suppression were more pronounced with triptorelin, resulting in a larger height gain.

Treatment with a luteinizing hormone-releasing hormone agonist in adolescents with short stature

BACKGROUND

Treatment with a luteinizing hormone-releasing hormone (LHRH) agonist increases adult height in children with LHRH-dependent precocious puberty and is prescribed by some practitioners to augment height in short adolescents. We performed a randomized clinical trial to determine whether treatment with an LHRH agonist increases adult height in short adolescents with normally timed puberty.

METHODS

Fifty short adolescents (18 boys and 32 girls) with low predicted adult height (mean [+/-SD], 3.3+/-1.2 SD below the population mean) received either placebo (24 subjects) or an LHRH agonist (26 subjects). The mean (+/-SD) duration of treatment was 3.5+/-0.9 years in the LHRH-agonist group and 2.1+/-1.2 years in the placebo group (P<0.001). Adult height was measured when bone age exceeded 16 years in girls and 17 years in boys and when the rate of growth was less than 1.5 cm per year.

RESULTS

Forty-seven adolescents (94 percent) were followed until they attained adult height. At the time adult height was achieved, the subjects who had been treated with an LHRH agonist were older than those who had received placebo (20.5+/-2.1 years vs. 18.0+/-2.5 years, P=0.01) and were taller (standard-deviation score, -2.2+/-1.1 vs. -3.0+/-1.2; P=0.01). Analysis of covariance showed that LHRH-agonist treatment resulted in an increase of 0.6 (95 percent confidence interval, 0.2 to 0.9) in the standard-deviation score for height, or an increase of 4.2 cm (95 percent confidence interval, 1.7 to 6.7), over the initially predicted adult height (P=0.01). Treatment with an LHRH agonist resulted in significantly greater adult height than did placebo in boys and girls, in adolescents with idiopathic short stature, and in those who had a growth-limiting syndrome. The principal adverse event in the LHRH-agonist group was decreased accretion of bone mineral density (mean lumbar vertebral bone mineral density at the time adult height was achieved, 1.6+/-1.2 SD below the population mean, vs. 0.3+/-1.2 SD below the population mean in the placebo group; P<0.001).

CONCLUSIONS

Treatment with an LHRH agonist for 3.5 years increases adult height by 0.6 SD in adolescents with very short stature but substantially decreases bone mineral density. Such treatment cannot be routinely recommended to augment height in adolescents with normally timed puberty.

Human growth hormone and gonadotropin releasing hormone analog combination therapy increases predicted height in short normal girls

The "short normal" child constitutes a real challenge for the pediatric endocrinologist. In a subgroup of short normal children, puberty starts at a normal age but with low height, and hence, the final height is expected to be quite compromised. Efforts to improve the outcome in this group have been made in the past with equivocal results. We present the growth data of 8 short girls with normal growth hormone values on provocative testing and low height at puberty initiation. At intervention the height and the stage of puberty were 129.3 +/- 5 cm and II to III, respectively, and the predicted height was 148.8 +/- 2.6 cm. Gonadotropin releasing hormone analog, triptorelin (3.6 +/- 0.5 microg/kg/day) and growth hormone (0.5 IU/kg/week) were used in different sequential order and simultaneously in each child. The mean total treatment period was 47.6 +/- 11.2 months. The mean predicted and the mean final height in the total group were 148.8 +/- 2.6 and 154.5 +/- 3.6 cm, respectively (p:0.028). The final height did not differ from the target height (154.8 +/- 8 cm versus 154.5 +/- 3.6 cm), while in 4 children, the final height was greater than the target height. The height gain (delta Final height - Predicted height) was 5.7 +/- 1.3 cm. If we analyze separately the girls in whom growth hormone was started first and gonadotropin releasing hormone analog followed versus those who started the analog first, the delta Final height - Predicted height was 8 +/- 3 cm in the former and 4.8 +/- 3.1 cm in the latter (p:0.03). It seemed that the difference was accounted for by duration of growth hormone therapy (51.3 +/- 10.6 months versus 28.6 +/- 10.6 months) (p:0.026), rather than by other factors. In conclusion, under the conditions of the present study, the combination of puberty arrest and growth hormone therapy significantly improved predicted height. The most significant determinant of the height gain was the duration of growth hormone therapy.

The use of somatropin (recombinant growth hormone) in children of short stature

The availability of somatropin [recombinant human growth hormone (GH)] has revolutionized the treatment of short stature resulting from GH deficiency. It is also widely used as an adjunct in the treatment of other disorders which do not fit the definition of classic GH deficiency, such as intrauterine growth restriction, Turner syndrome, healthy children with short stature and skeletal dysplasias. The widespread use and ready availability of GH treatment has prompted questions about its tolerability, rationality, and the psychological effects of long-term treatment, leading to several trials. Early treatment of GH deficiency will allow the child to reach his or her genetic potential, although there continues to be marked variability in the criteria used to diagnose the deficiency, and in the treatment schedule, especially during puberty. Treatment has also been shown to have a beneficial effect on growth in children with chronic renal failure, with no adverse effects on the renal function. There are, however, no long-term data to determine final height, or randomized controlled studies to justify routine use of GH in conditions such as intrauterine growth restriction. It remains controversial in conditions such as Turner syndrome and achondroplasia, where the response to treatment is only moderate. Healthy children with short stature have not been shown to have a psychological disadvantage, again proving difficult to justify prolonged GH treatment for idiopathic short stature. Meticulous monitoring, long-term follow-up to adult or near-adult final height, and well-defined endpoints of treatment need to be better clarified. The metabolic effects of treatment on the patient's lipid profile, bone mineral density, and muscle mass need careful documentation, especially with the high doses used in an already susceptible population such as low birthweight children and those with Turner syndrome. Lastly, the psychosocial impact of GH treatment, financial implications, and cost efficacy of treatment in an ever-increasing list of indications should be taken into consideration for rationalizing its use in future.

Growth hormone and sex steroids. Interactions in puberty

Dynamic interactions among growth hormone, IGF-1, and sex steroidal hormones have a major role in the achievement of full height potential and the body composition changes in adolescence. Testosterone and estrogen affect the growth hormone neuroendocrine rhythms, and growth hormone, in turn, potentiates many of the metabolic actions of the sex steroids. Leptin is also thought to have a key regulatory role in the process of sexual development in the child, but the precise nature of these interactions is unclear. The targeted replacement of hormonal deficiencies in puberty and manipulation of the timing of pubertal maturation have resulted in better strategies to treat profoundly short children during this period; however, more research is needed to determine the consequences of such approaches in aspects of metabolism other than linear growth.

Optimizing gh therapy in adults and children

Until the advent of modern neuroradiological imaging techniques in 1989, a diagnosis of GH deficiency in adults carried little significance other than as a marker of hypothalamo-pituitary disease. The relatively recent recognition of a characteristic clinical syndrome associated with failure of spontaneous GH secretion and the potential reversal of many of its features with recombinant human GH has prompted a closer examination of the physiological role of GH after linear growth is complete. The safe clinical practice of GH replacement demands a method of judging overall GH status, but there is no biological marker in adults that is the equivalent of linear growth in a child by which to judge the efficacy of GH replacement. Assessment of optimal GH replacement is made difficult by the apparent diverse actions of GH in health, concern about the avoidance of iatrogenic acromegaly, and the growing realization that an individual's risk of developing certain cancers may, at least in part, be influenced by cumulative exposure to the chief mediator of GH action, IGF-I. As in all areas of clinical practice, strategies and protocols vary between centers, but most physicians experienced in the management of pituitary disease agree that GH is most appropriately begun at low doses, building up slowly to the final maintenance dose. This, in turn, is best determined by a combination of clinical response and measurement of serum IGF-I, avoiding supraphysiological levels of this GH-dependent peptide. Numerous studies have helped define the optimum management of GH replacement during childhood. The recent requirement to measure and monitor GH status in adult life has called into question the appropriateness of simplistic weight- and surface area-based dosing regimens for the management of GH deficiency in childhood, with reliance on linear growth as the sole marker of GH action. It is clear that the monitoring of parameters other than linear growth to help refine GH therapy should now be incorporated into childhood GH treatment protocols. Further research will be required to define the optimal management of the transition from pediatric to adult GH replacement; this transition will only be possible once the benefits of GH in mature adults are defined and accepted by pediatric and adult endocrinologists alike.

Is there a place for combined therapy with GnRH agonist plus growth hormone in improving final height in short statured children?

The availability of recombinant human growth hormone (GH) and the optimization of substitutive therapy have improved final growth in children with GH deficiency, but despite this some of them fail to grow to their genetic potential. In particular, this may occur in patients who started the substitutive therapy too late and/or in whom bone age progressed too fast during GH administration. In these patients, with unfavorable auxological characteristics, the administration of a GnRH agonist in combination with GH may slow down bone maturation and prolong prepubertal growth, mimicking, to some extent, the growth pattern of patients with GH + Gn deficiency who grow better than children with isolated GHD. A different condition in which such a combined therapy might be used is the short normal child. As they are short but normally-growing children, the onset of puberty is in general appropriate for their chronological age but precocious for their height age. Thus, slowing down pubertal maturation may increase the time available for growth. GH would sustain growth during both GnRHa administration and after its withdrawal, when puberty starts again. Our preliminary results suggest that the administration of GH + GnRHa in combination may have a positive effect on final height in selected children with isolated GHD and in short normal children.

Estrogen suppression in males: metabolic effects

We have shown that testosterone (T) deficiency per se is associated with marked catabolic effects on protein, calcium metabolism, and body composition in men independent of changes in GH or insulin-like growth factor I production. It is not clear,,however, whether estrogens have a major role in whole body anabolism in males. We investigated the metabolic effects of selective estrogen suppression in the male using a potent aromatase inhibitor, Arimidex (Anastrozole). First, a dose-response study of 12 males (mean age, 16.1 +/- 0.3 yr) was conducted, and blood withdrawn at baseline and after 10 days of oral Arimidex given as two different doses (either 0.5 or 1 mg) in random order with a 14-day washout in between. A sensitive estradiol (E2) assay showed an approximately 50% decrease in E2 concentrations with either of the two doses; hence, a 1-mg dose was selected for other studies. Subsequently, eight males (aged 15-22 yr; four adults and four late pubertal) had isotopic infusions of [(13)C]leucine and (42)Ca/(44)Ca, indirect calorimetry, dual energy x-ray absorptiometry, isokinetic dynamometry, and growth factors measurements performed before and after 10 weeks of daily doses of Arimidex. Contrary to the effects of T withdrawal, there were no significant changes in body composition (body mass index, fat mass, and fat-free mass) after estrogen suppression or in rates of protein synthesis or degradation; carbohydrate, lipid, or protein oxidation; muscle strength; calcium kinetics; or bone growth factors concentrations. However, E2 concentrations decreased 48% (P = 0.006), with no significant change in mean and peak GH concentrations, but with an 18% decrease in plasma insulin-like growth factor I concentrations. There was a 58% increase in serum T (P = 0.0001), sex hormone-binding globulin did not change, whereas LH and FSH concentrations increased (P < 0.02, both). Serum bone markers, osteocalcin and bone alkaline phosphatase concentrations, and rates of bone calcium deposition and resorption did not change. In conclusion, these data suggest that in the male 1) estrogens do not contribute significantly to the changes in body composition and protein synthesis observed with changing androgen levels; 2) estrogen is a main regulator of the gonadal-pituitary feedback for the gonadotropin axis; and 3) this level of aromatase inhibition does not negatively impact either kinetically measured rates of bone calcium turnover or indirect markers of bone calcium turnover, at least in the short term. Further studies will provide valuable information on whether timed aromatase inhibition can be useful in increasing the height potential of pubertal boys with profound growth retardation without the confounding negative effects of gonadal androgen suppression.

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency

More than 90% of cases of congenital adrenal hyperplasia (CAH, the inherited inability to synthesize cortisol) are caused by 21-hydroxylase deficiency. Females with severe, classic 21-hydroxylase deficiency are exposed to excess androgens prenatally and are born with virilized external genitalia. Most patients cannot synthesize sufficient aldosterone to maintain sodium balance and may develop potentially fatal "salt wasting" crises if not treated. The disease is caused by mutations in the CYP21 gene encoding the steroid 21-hydroxylase enzyme. More than 90% of these mutations result from intergenic recombinations between CYP21 and the closely linked CYP21P pseudogene. Approximately 20% are gene deletions due to unequal crossing over during meiosis, whereas the remainder are gene conversions--transfers to CYP21 of deleterious mutations normally present in CYP21P. The degree to which each mutation compromises enzymatic activity is strongly correlated with the clinical severity of the disease in patients carrying it. Prenatal diagnosis by direct mutation detection permits prenatal treatment of affected females to minimize genital virilization. Neonatal screening by hormonal methods identifies affected children before salt wasting crises develop, reducing mortality from this condition. Glucocorticoid and mineralocorticoid replacement are the mainstays of treatment, but more rational dosing and additional therapies are being developed.