Long-term response to recombinant human growth hormone treatment: a new predictive mathematical method

INTRODUCTION

Recombinant GH has been offered to GH-deficient (GHD) subjects for more than 30 years, in order to improve height and growth velocity in children and to enhance metabolic effects in adults.

AIM

The aim of our work is to describe the long-term effect of rhGH treatment in GHD pediatric patients, suggesting a growth prediction model.

MATERIAL AND METHODS

A homogeneous database is defined for diagnosis and treatment modalities, based on GHD patients afferent to Hospital Regina Margherita in Turin (Italy). In this study, 232 GHD patients are selected (204 idiopathic GHD and 28 organic GHD). Each measure is shown in terms of mean with relative standard deviations (SD) and 95% confidence interval (95% CI). To estimate the final height of each patient on the basis of few measures, a mathematical growth prediction model [based on Gompertzian function and a mixed method based on the radial basis functions (RBFs) and the particle swarm optimization (PSO) models] was performed.

RESULTS

The results seem to highlight the benefits of an early start of treatment, further confirming what is suggested by the literature. Generally, the RBF-PSO method shows a good reliability in the prediction of the final height. Indeed, RMSE is always lower than 4, i.e., in average the forecast will differ at most of 4 cm to the real value.

CONCLUSIONS

In conclusion, the large and accurate database of Italian GHD patients allowed us to assess the rhGH treatment efficacy and compare the results with those obtained in other Countries. Moreover, we proposed and validated a new mathematical model forecasting the expected final height after therapy which was validated on our cohort.

[Unidentified bright objects and neuropsychiatric disturbances]

AIM

The neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disease. In 40-70% of cases are described signal hyperintensity on MRI, called unidentified bright objects (UBO). Their correlation with clinical disorders is still debated. The present study investigated the correlation between the UBOs and neuropsychiatric outcomes overall, observes the long-term through the comparison of MRI brain and considers the utility of including MRI early in the investigation of NF1.

METHODS

We included 100 patients (age 2-18 years) with NF1. The parents were given a medical questionnaire to fill, a clinical neurologic examination (Touwen) was performed and brain MRI were analyzed during the years.

RESULTS

In 72% of cases were detected UBO's last MRI. It was observed that the UBO's tend to shrink over time and in some cases to disappear in pre-adolescent. There were significant correlations between UBOs and minor disturbances in motor function (P=0.004) and between UBO's and cognitive deficits (P=0.016). The 79.62% of the patients is followed by a specialist in neuropsychiatry, as correlated significantly (P=0.027) with changes on MRI.

CONCLUSIONS

Given the correlation between UBO's, neurological disorders, cognitive and behavioral, suggest be included in the diagnostic protocol MRI brain areas as T2H can be considered predictive for a neuropsychiatric disorder.

Is TW3 Height Prediction More Accurate than TW2? Preliminary Data

BACKGROUND/AIMS

Skeletal maturation is considered a reliable variable in evaluating the 'tempo' of growth. It is important in the diagnosis of endocrinological diseases, in chronic diseases, in hormonal therapy follow-up and in computing height prediction for prognostic and therapeutic purposes. It is also used when chronological age is not available for minors without known birth dates. There are different methods to evaluate skeletal maturation and height prediction. The Tanner-Whitehouse (TW) method 2 (TW2) has been considered to be the most useful method so far, and has recently been updated with modified height prediction equations (TW2-Mark II). TW3 is the newest method. The aim of this study is to evaluate whether TW3 is more accurate in the assessment of height prediction than TW2-Mark II in a sample of healthy north Italian subjects.

METHODS

Anthropometrical data were collected as part of a survey in 1977-1978 in Turin. The sample involved 1,384 healthy children. The children, now adults, have been traced and recalled to measure their final height in order to test height prediction reliability. At present, we have collected 118 adult heights.

RESULTS

According to the TW2 method 40% of the males had a height prediction error larger than +/- residual SD (4.1 cm), and with TW3 this was 32.9%. The female height prediction error with TW2 was larger than +/- residual SD (3.6 cm) in 29.2% of girls, and the same value was found with TW3.

CONCLUSION

According to our preliminary data, TW3 does not represent any real progress.

Incidence and prevalence rate estimation of GH treatment exposure in Piedmont pediatric population in the years 2002-2004: Data from the GH Registry

OBJECTIVE

The aim of this study is to estimate the annual incidence and prevalence rate of the GH treatment exposure in patients under the age of 18 treated for hypopituitarism or isolated GH deficiency (GHD) in Piedmont, during the period January 1, 2002 to December 31, 2004.

METHODS

The selection criteria for recombinant human GH (rhGH) treatment in childhood were approved by the Ministry of Health in Italy in the yr 1998. The present analysis is based on data from the Registry of subjects receiving GH therapy (GH Registry) made up of the 918 pediatric patients (age <18 yr) with a diagnosis of GHD (excluding Prader-Willi and Turner syndromes and other conditions), diagnosed in the period January 1, 2002 - December 31, 2004. The case series has been described as regards the number of cases per year of diagnosis; the prevalence and incidence rates, calculated per 10,000 (per ten thousand) inhabitants, are given for each year of the study period.

RESULTS

The prevalence rate increases slightly from 8.62 per thousand in 2002 to 9.44 per thousand in 2004 and the incidence rates estimated were 2.49 per ten thousand, 1.86 per ten thousand and 1.97 per ten thousand in the yr 2002, 2003 and 2004, respectively.

CONCLUSION

The Piedmont GH Registry represents the first database available in Italy and could set an example for the other Italian regions as well.

Variation of bone age progression in healthy children

Bone age assessments were related to auxological variables in 407 Italian boys, between 7 and 12 years of age, in order to elucidate the factors that affect the rate of skeletal maturation and to examine the possibility of using measures of skeletal maturation of evaluate individual patients. Using the radius-ulna-short bones (RUS) method of assessment, bone age velocity was greater in the Italian boys than for the UK reference standards, although there was considerable interindividual dispersion around the mean. Bone age velocity and height velocity were poorly correlated, and there was little correlation between skeletal and pubertal maturation. There was a slight positive correlation between bone age velocity and height SDS and between bone age velocity and body mass index. Bone age estimations using RUS were greater than those obtained using the carpus. In conclusion, the marked interindividual deviation in measured bone ages makes it difficult to relate data on an individual basis to other measures of growth and maturation

Is the persistence of isolated GH deficiency in adulthood predicted by anatomical hypothalamic-pituitary alterations?

The aim of this study was to verify the persistence in adulthood of GH deficiency diagnosed in childhood and treated with hGH in childhood and to study whether anatomical hypothalamic-pituitary alterations evaluated by magnetic resonance (MR) imaging could predict it. To this goal, in six GHD adults (3 males and 3 females aged 17.2-24.5 yr, BMI 21.8 +/- 1.3), we studied anterior pituitary hormone response to GHRH (1 microgram/kg iv)+pyridostigmine (120 mg po)+ GnRH (100 micrograms iv) +TRH (400 micrograms iv)+hCRH (100 micrograms iv) as well as brain MR imaging. In childhood, the diagnosis of severe isolated GHD had been done based on auxological findings as well as on GH response < 7 micrograms/L after two classical provocative stimuli. In the present study, hormonal responses showed the persistence of severe isolated GHD in 4 out of 6 patients (peak, mean +/- SEM: 3.8 +/- 0.6, range 2.6-4.8 micrograms/L). In these patients, IGF-I levels were found low or low-normal. In other 2 patients, a clear GH response to stimulation (peak: 51.3 and 43.0 micrograms/L, respectively) together with normal IGF-I levels were found. No other anterior pituitary hormone deficiency was present in all subjects. MR imaging showed pituitary hypoplasia in all patients with persistent GHD; in 2 out of them, pituitary stalk interruption and ectopic neurohypophysis was also present. On the other hand, MR imaging showed normal hypothalamo-pituitary morphology in the 2 subjects with normal somatotrope response. In conclusion, our present data indicate that testing with a potent stimulus such as GHRH+pyridostigmine is a reliable method to assess the persistence of GH deficiency which associates with anatomical hypothalamic-pituitary alterations at the MR imaging. Patients with transient GH deficiency in childhood and normal pituitary GH reserve in adulthood have normal hypothalamic-pituitary MR imaging.

Main problems associated with bone age and maturity evaluation

In scientific papers, skeletal maturation-expressed as bone maturity scores or bone age-is often used as a quantifiable variable similar to height or weight. This paper discusses whether this approach is appropriate. The questions addressed are whether skeletal maturation can be measured on a quantitative scale, whether its use is appropriate in computing, and what the 'numbers' used represent. Reference will be made mainly to the Tanner-Whitehouse method, which, in the opinion of the authors, has been the most reliable method of assessment to date. Many of the remarks made in this paper may be extended to other methods of assessment, and have been stressed by Tanner himself. The authors are aware that, in the future, some of the remarks could be made redundant by the development of more detailed definitions of bone maturation. This is becoming feasible with the advent of expert systems for the automatic recognition of different stages of bone maturation.

[Magnetic resonance in the study of patients of short stature of the hypothalamo-hypophyseal origin. Report on 29 cases]

Although growth hormone (GH) deficiency is a very common cause of short stature, many cases are still diagnosed as idiopathic. Magnetic Resonance Imaging (MRI), more clearly than CT, reveals the anatomy of the hypothalamic-hypophyseal region and of the possible alterations (pituitary hypoplasia, interruption of the stalk) causing hormonal deficit. Twenty-nine patients with short stature underwent MRI examinations of the hypothalamic-pituitary region to assess the significance of the correlation between hormonal test and MR patterns. Five patients had normal variants of short stature (NVSS), 7 had multiple pituitary hormone defects (MPHD) and 17 had isolated growth hormone deficiency (IGHD). In patients with MPHD or with severe isolated growth hormone deficit MRI shows interruption of the pituitary stalk with ectopy of the neurohypophysis or a mass. In patients with less severe IGHD and in NVSS, MRI demonstrates a normal pituitary region or a slightly hypoplastic gland, the neurohypophysis being normally situated. MRI may provide an ethiological classification in short stature patients. Typical MR patterns can be demonstrated in cases of dwarfism secondary to a mass in the hypothalamic-pituitary region or to morphological changes of the pituitary stalk, while in transient GH deficit no anatomical abnormalities are observed.

Turner's syndrome in Italy: familial characteristics, neonatal data, standards for birth weight and for height and weight from infancy to adulthood

In 1990, the Italian Study Group for Turner's Syndrome (ISGTS) undertook a nationwide survey, involving the retrospective collection of cross-sectional data and longitudinal growth profiles of 772 girls with Turner's syndrome born between 1950 and 1990. The study was carried out in 29 pediatric endocrinological centers. In this first report, the familial characteristics and neonatal data of Turner girls are described, compared to those of the general population, and related to postnatal somatic development. Furthermore, charts for birth weight and growth standards for height and weight from infancy to adulthood are presented (these are the first charts based on a large sample from the Mediterranean area). The main findings were: (1) incidence of Turner births increases with parental age or parity; (2) most of the neonates are small for dates; (3) girls with normal birth weight tend to be both taller and heavier than girls with low birth weight during the whole growth period; and (4) a 10-cm difference in midparental height leads to a 6.5-cm difference in adult stature.

Final height in sexually precocious girls after therapy with an intranasal analogue of gonadotrophin-releasing hormone (buserelin)

Twenty-two girls affected by sexual precocity with impaired final height prognosis were followed until they achieved final height. Twelve of them were treated with an intranasal (D-Ser6)-gonadotrophin-releasing hormone (GnRH) analogue (buserelin) administered at a mean dose of 25 micrograms/kg/day (range 20-32) for a mean period of 14 months (range 8-18). Ten girls refused treatment. Mean final height of the treated girls was 157.3 +/- 8.2 cm, significantly (p = 0.03) higher than the 149.7 +/- 5.5 cm of untreated patients. Treated girls surpassed midparental height (+1.7 cm) while untreated girls reached the lower part of target zone (-3.5 cm). Our data suggest that intranasal buserelin treatment preserves final height in girls with sexual precocity and initially impaired height prognosis.

Magnetic resonance and the diagnosis of short stature of hypothalamic-hypophyseal origin

Magnetic resonance imaging was performed in 23 patients with short stature (7 had multiple pituitary hormone defect, 11 had isolated growth hormone deficiency and 5 had normal variant short stature) to investigate if there is a relation between magnetic resonance findings and results of endocrine tests. Magnetic resonance imaging of patients with multiple pituitary hormone deficiency or with serious isolated growth hormone deficiency (growth hormone < 3 micrograms/l) revealed an interrupted pituitary stalk and ectopic neurohypophysis or a mass. In patients with less serious isolated growth hormone deficiency (growth hormone > 3 micrograms/l) or with normal variant short stature, the technique revealed a normal or hypoplastic hypophysis. Magnetic resonance appears to be a useful second-level diagnostic tool in defining the type of alteration in growth defects of endocrine origin.

[Growth velocity in thalassemic children receiving different protocols of chelating therapy]

The aim of this study was to compare growth velocity in thalassemic children using two different treatment protocols. Thalassemic children were initially treated with high daily doses of desferrioxamine, obtaining a good rate of initial growth which then unexpectedly slowed down later. The introduction of a new treatment protocol reducing both the dose and frequency with which the drug was administered provoked a significant increase in the rate of growth greater than that observed in the group treated using the previous protocol.

[Auxological evaluation of a patient with Dubowitz syndrome]

The Authors describe the growth of a 2 year old child affected by Dubowitz syndrome. The child came to their observation because of short stature and microcephaly.

The effect of galanin on baseline and GHRH-induced growth hormone secretion in obese children

We have evaluated the effect of the administration of galanin (Gal), a newly identified hypothalamic peptide, on baseline and GHRH-induced GH rise in five obese children and in seven controls. The GH response to GHRH (hpGRF(1-29), 1 microgram/kg i.v.), and to Gal (15 micrograms/kg/h for 1 h), evaluated both as the maximum GH peak and as integrated area under the curve (AUC), was significantly lower in the obese children than in the controls. Simultaneous administration of Gal plus GHRH significantly increased the GH response to GHRH in all the obese subjects, so that their mean peak GH levels and AUC after Gal plus GHRH were similar to those of the control children after GHRH. Also, in control children Gal caused a significant augmentation of the GH response to GHRH. Mean peak GH levels and mean AUC after Gal plus GHRH were significantly higher in the controls than in the obese children given the same treatment. Our data indicate that obese children have a blunted GH response to Gal, which, however, is able to enhance the GH response to GHRH. This observation strengthens the view that the mechanism of action of Gal involves modulation of endogenous somatostatin (SRIH) release. In addition, similarity between the effects of Gal and pyridostigmine on baseline and GHRH-stimulated GH release in obese children may indicate the existence of a cholinergic link in the action of Gal.

Evidence for involvement of endogenous somatostatin in the galanin-induced growth hormone secretion in children

We have evaluated the effects of the combined administration of Galanin (Gal) plus growth hormone-releasing hormone (GHRH) and of pyridostigmine (PD), a cholinergic agonist, plus Gal on GH secretion in 15 children (12 males and three females, age 7.7-14.5 y) with short stature. Children were subdivided into two groups. In group 1 (n = 7) Gal (15 micrograms/kg h i.v.) plus GHRH (1 microgram/kg i.v.) administration induced a higher GH rise (peak = 73.1 +/- 10.2 ng/mL, mean +/- SD; area under the curve (AUC) = 531.9 +/- 78.7 ng.min.mL-1) than did GHRH alone (peak = 38.9 +/- 26.5 ng/mL, p less than 0.05; AUC = 256.9 +/- 165.6 ng/mL/min-1, p less than 0.005). Gal had a synergistic effect on the GHRH-induced GH response because the GHRH plus Gal AUC response was significantly higher (p less than 0.01) than the sum of the areas of response to GHRH and Gal alone. In group 2 (n = 8) PD administration (60 mg/kg p.o.) had no significant effects on the Gal-induced GH secretion (peak = 14.9 +/- 8.8 and 16.0 +/- 9.8 ng/mL after Gal and PD + Gal, respectively; AUC = 91.2 +/- 52.1 and 125.2 +/- 83.6 ng.mL.min-1 after Gal and PD + Gal, respectively). Our results confirm the ability of Gal to stimulate GH secretion in children, and strengthen the view that its mechanism of action involves modulation of endogenous somatostatin release.