Serum insulin-like growth factor-I (IGF-I) reference ranges for chemiluminescence assay in childhood and adolescence. Data from a population of in- and out-patients

Challenges of insulin-like growth factor-1 testing

Insulin-like growth factor 1 (IGF-1), primarily synthesized in the liver, was initially discovered due to its capacity to replicate the metabolic effects of insulin. Subsequently, it emerged as a key regulator of the actions of growth hormone (GH), managing critical processes like cell proliferation, differentiation, and apoptosis. Notably, IGF-1 displays a longer half-life compared to GH, making it less susceptible to factors that may affect GH concentrations. Consequently, the measurement of IGF-1 proves to be more specific and sensitive when diagnosing conditions such as acromegaly or GH deficiency. The recognition of the existence of IGFBPs and their potential to interfere with IGF-1 immunoassays urged the implementation of various techniques to moderate this issue and provide accurate IGF-1 results. Additionally, in response to the limitations associated with IGF-1 immunoassays and the occurrence of discordant IGF-1 results, modern mass spectrometric methods were developed to facilitate the quantification of IGF-1 levels. Taking advantage of their ability to minimize the interference caused by IGF-1 variants, mass spectrometric methods offer the capacity to deliver robust, reliable, and accurate IGF-1 results, relying on the precision of mass measurements. This also enables the potential detection of pathogenic mutations through protein sequence analysis. However, despite the analytical challenges, the discordance in IGF-1 reference intervals can be attributed to a multitude of factors, potentially leading to distinct interpretations of results. The establishment of reference intervals for each assay is a demanding task, and it requires nationwide multicenter collaboration among laboratorians, clinicians, and assay manufacturers to achieve this common goal in a cost-effective and resource-efficient manner. In this comprehensive review, we examine the challenges associated with the standardization of IGF-1 measurement methods, the minimization of pre-analytical factors, and the harmonization of reference intervals. Particular emphasis will be placed on the development of IGF-1 measurement techniques using "top-down" or "bottom-up" mass spectrometric methods.

Difficulties in Interpreting IGF-1 Levels in Short Stature Children Born Small for Gestational Age (SGA) Treated with Recombinant Human Growth Hormone (rhGH) Based on Data from Six Clinical Centers in Poland

The assessment of IGF-1 concentrations is one of the parameters used for evaluating response to rhGH treatment. An increase in IGF-1 concentration positively correlates with growth improvement, whereas IGF-1 concentrations significantly above the reference range may increase the risk of possible side effects. The aim of this study was to evaluate the IGF-1 local reference ranges for the rhGH treatment centers concerned and to compare these values with the population reference ranges. A retrospective analysis was conducted on auxological data from 229 SGA patients who received rhGH treatment between 2016 and 2020 at six university clinical centers in Poland. The IGF-1 levels were assessed at baseline, after 12 and 24 months, and compared to the reference ranges provided by the local laboratory and to the population reference ranges. After 12 months, 56 patients (24%) presented IGF-1 values > 97th percentile for the local reference range, whereas only 8 (3.5%) did so using the population reference ranges; p < 0.001. After 24 months of treatment, the values were: 47 (33%) > 97th percentile by local vs. 6 (4.2%) by population standards; p < 0.001. Thirty-nine patients had rhGH dose reduced after 12 months, of whom twelve (25%) had IGF-1 > 97th percentile according to the local reference ranges and five (13%) > 97th percentile for the population. Our data suggest that different methods used to determine IGF-1 concentration and the different IGF-1 reference ranges result in a significant proportion of rhGH-treated children with elevated IGF-1 concentration and experiencing dose reductions, which may negatively affect growth rate.

Efficacy of short-term induction therapy with low-dose testosterone as a diagnostic tool in the workup of delayed growth and puberty in boys

PURPOSE

Constitutional delay of growth and puberty (CDGP) represents the most frequent cause of delayed puberty in males, sharing some clinical features with growth hormone deficiency (GHD) and isolated hypogonadotropic hypogonadism (IHH). Short-term induction therapy (SIT) has been approved for the induction of puberty in CDGP. We aim to investigate the efficacy of SIT with transcutaneous testosterone gel (TTG) or intramuscular testosterone therapy (IMTT) in a cohort of CDGP subjects, compared to clinical observation. Furthermore, we aim to evaluate the role of SIT as a diagnostic tool to differentiate CDGP from GHD and IHH subjects.

METHODS

The retrospective study included 246 male subjects with delayed puberty. The study population was divided into three groups: TTG, IMTT, and control group (CNT).

RESULTS

At 6 months observation, height velocity (HV) was significantly increased in both treated groups compared to CNT group, particularly higher in TTG than IMTT group. A significant testicular enlargement was revealed in both CNT and TTG group compared to IMTT group. Furthermore, LH value was significantly greater in TTG compared to IMTT group. IGF-1 values after SIT rose significantly in both treated groups compared to CNT group. Moreover, almost all GH provocative tests performed after SIT showed a normal GH response.

CONCLUSION

SIT with TTG appears to be more effective to induce growth spurt, better tolerated and with a more physiological effect on pubertal induction compared to IMTT in CDGP population. Finally, TTG might be a useful tool in the diagnostic work up to discriminate CDGP from GHD or IHH.

The expression level of mir-21-3p in platelet-rich plasma: A potential effective factor and predictive biomarker in recurrent implantation failure

Recurrent implantation failure (RIF) is the most important complication associated with in vitro fertilization (IVF). Despite the good quality of the transferred embryo, the success rate is rather disappointing. Therefore, predictive biomarkers for implantation are critical to making decisions about transferring high-quality embryos or cryopreserving them for cycles with a higher chance of implantation. Recently, intrauterine infusion of autologous platelet-rich plasma (PRP) has been proposed to increase the endometrial receptivity in RIF patients. PRP is rich in both growth factors and microRNAs (miRNAs). We investigated the possible association of mir-21-3p, mir-21-5p, mir-494-3p, mir-145-5p, and insulin-like growth factor-I (IGF-I) levels in PRP and platelet-poor plasma (PPP) samples with the pregnancy outcomes in RIF patients. The miRNA expression level and IGF-I concentration were assessed using real-time PCR and chemiluminescence methods respectively. Mir-21-3p was upregulated in PRP samples of the pregnant group in comparison to the nonpregnant group. There was no difference in the expression of mir-21-3p in PPP samples of these groups. The concentration of IGF-I was higher in PRP and PPP samples of the nonpregnant in comparison to the pregnant group. Receiver-operating characteristic curve analysis showed that mir-21-3p can be a valuable biomarker for the prediction of pregnancy chance in RIF patients treated with PRP.

Rethinking the Management of Optic Pathway Gliomas: A Single Center Experience

Background

Optic pathway gliomas (OPGs) are rare neoplasms in children with an unpredictable clinical course. Approximately 15% of OPGs occur in patients affected by neurofibromatosis type 1 (NF1): the clinical course of these cases is more indolently than sporadic ones, and NF1 patients less frequently require treatment including surgery. Instead, over 90% of sporadic OPGs require one or more therapeutic approaches. The management of OPG is controversial. They are also characterized by a high risk of morbidity including hypothalamic damage, endocrine deficits, visual deficit and/or neurological impairment.

Materials and Methods

In this paper, we evaluated visual and endocrinological outcomes of a population of OPG followed at our center from 2013 to 2021, with a particular emphasis on the role of surgery.

Results

Twenty-six patients were included in this study (mean age of 40.7 months). Tumor location on imaging was described by the Dodge classification. Five cases had NF 1. Thirteen cases received biopsy and 13 were partially resected. Histopathology revealed 19 cases of pilocytic astrocytomas, 2 pilomyxoid astrocytoma and 5 ganglioglioma. All the patients required a post-surgical adjuvant treatment according to current indications for low-grade gliomas. Molecular studies (BRAF status and mTOR/pmTOR pathway) have been performed in 24/26 patients, following for the use of target therapy in 11 of these patients. In our study we found that patients underwent biopsy have a better visual and endocrinological outcomes rather than patients with a tumor debulking. The five-year overall survival rate is 98% with a mean follow-up of 60 months.

Conclusions

Many children with OPGs survive with a residual tumor. They suffer from chronic diseases such as endocrine dysfunction, visual disturbance, motor deficits and poor quality of life. All patients need comprehensive diagnostic work-up including neuroimaging, clinical evaluations and neuropathology approach; at the same time, they need therapeutic decisions and concepts for the choice of timing and type of neurosurgical intervention, chemotherapy and target therapy as well as surveillance and rehabilitation to maximize survival and overall functional outcomes. Our study showed that minimal invasive surgery with the purpose of molecular characterization of the tumor is desirable to reduce morbidity correlate to surgery.

Response to Treatment with Recombinant Human Growth Hormone (rhGH) of Short Stature Children Born Too Small for Gestational Age (SGA) in Selected Centres in Poland

Short stature resulting from SGA is an obligatory indication for treatment with rhGH. The aim of the study was to assess the response to rhGH treatment in patients treated in the years 2016−2020 in six clinical centers in Poland. During the analysis, auxological data were collected, and anthropometrical parameters (Ht, SDS Ht, HV and ΔHV) were reassessed. Subgroups of patients with dysmorphic features (DYSM), fetal alcohol syndrome (FAS) and Silver-Russel syndrome (SRS) were selected. The study group consisted of 235 children (137 boys). The medium initial age was 9.08 years, and 190 patients were in the prepubertal stage. The poor response to treatment was defined as ΔHt SDS < 0.3 and/or ΔHV < 3 cm/year. Seventeen per cent of all patients after the first year and 44% after the second year met the ΔHt SDS < 0.3 criterion, and 56% during the first and 73% during the second year met the ΔHV < 3 cm/year criterion. Our data suggest that patients with SRS may show the best response to treatment, which was sustained throughout the follow-up period. The best response in all subgroups was observed during the first 12 months of therapy. Although the proportion of patients meeting the poor response criteria was high, only a few patients exceeded the 97th percentile for IGF-1 concentration during the first year of treatment. This might suggest that increasing the dose of rhGH in the second treatment year in order to sustain accelerated HV would be safe in these patients.

Human Breast Extracellular Matrix Microstructures and Protein Hydrogel 3D Cultures of Mammary Epithelial Cells

Simple Summary

Human breast tissue extracellular matrix (ECM) is a microenvironment essential for the survival and biological activities of mammary epithelial cells. The ECM structural features of human breast tissues remain poorly defined. In this study, we identified the structural and mechanical properties of human normal breast and invasive ductal carcinoma tissue ECM using histological methods and atomic force microscopy. Additionally, a protein hydrogel was generated using human breast tissue ECM and defined for its microstructural features using immunofluorescence imaging and machine learning. Furthermore, we examined the three-dimensional growth of normal mammary epithelial cells or breast cancer cells cultured on the ECM protein hydrogel, where the cells exhibited biological phenotypes like those seen in native breast tissues. Our data provide novel insights into cancer cell biology, tissue microenvironment mimicry and engineering, and native tissue ECM-based biomedical and pharmaceutical applications.

Abstract

Tissue extracellular matrix (ECM) is a structurally and compositionally unique microenvironment within which native cells can perform their natural biological activities. Cells grown on artificial substrata differ biologically and phenotypically from those grown within their native tissue microenvironment. Studies examining human tissue ECM structures and the biology of human tissue cells in their corresponding tissue ECM are lacking. Such investigations will improve our understanding about human pathophysiological conditions for better clinical care. We report here human normal breast tissue and invasive ductal carcinoma tissue ECM structural features. For the first time, a hydrogel was successfully fabricated using whole protein extracts of human normal breast ECM. Using immunofluorescence staining of type I collagen (Col I) and machine learning of its fibrous patterns in the polymerized human breast ECM hydrogel, we have defined the microstructural characteristics of the hydrogel and compared the microstructures with those of other native ECM hydrogels. Importantly, the ECM hydrogel supported 3D growth and cell-ECM interaction of both normal and cancerous mammary epithelial cells. This work represents further advancement toward full reconstitution of the human breast tissue microenvironment, an accomplishment that will accelerate the use of human pathophysiological tissue-derived matrices for individualized biomedical research and therapeutic development.

Exercise-induced GH secretion is related to puberty

PURPOSE

Exercise represents a physiological stimulus that initiates the coordinated responses of hypothalamic-pituitary axis and sympathetic nervous system. Aims of the study were: 1) to analyze the response of GH, cortisol and prolactin to acute exercise in healthy children with normal GH response to stimulation tests 2) to evaluate the reliability of physical exercise as a screening test for GH secretion.

METHODS

Forty-four children (mean age 9.35 ± 2.69 years, range 4-13.7) underwent standardized Bruce's test on treadmill. Twenty-nine children were pre-pubertal (nine females and 20 males) and 15 children were pubertal (ten females and five males).

RESULTS

Exercise elicited a peak secretion of all the analyzed hormones. GH showed the highest mean percentage increase (558%), followed by prolactin (178%) and cortisol (23%). In 19/44 children (43.2%), GH peak did not reach the cut-off level of 8 ng/ml, considered as the normal GH response to stimulation tests. Despite a wide inter-individual variability, both GH peak and GH increase from baseline were higher in pubertal children than in pre-pubertal ones (GH peak: 13.49 ± 10.28 ng/ml versus 6.6 ± 4.09 ng/ml-p < 0.001; GH increase: 12.02 ± 10.30 ng/ml versus 5.28 ± 3.97 ng/ml-p < 0.001). The impact of puberty on both GH peak and GH increase was independent of sex, age, BMI SDS and VO₂max. No differences related to sex or pubertal status were found in cortisol and prolactin responses.

CONCLUSION

Exercise-induced GH secretion should not be considered a valuable screening tool in the diagnostic work-up of GH deficiency, due to the wide inter-individual variability in GH response. As described for standard GH stimulation tests, puberty represents the key factor that enhances GH secretion in healthy children.

Important Tools for Use by Pediatric Endocrinologists in the Assessment of Short Stature

Assessment and management of children with growth failure has improved greatly over recent years. However, there remains a strong potential for further improvements by using novel digital techniques. A panel of experts discussed developments in digitalization of a number of important tools used by pediatric endocrinologists at the third 360° European Meeting on Growth and Endocrine Disorders, funded by Merck KGaA, Germany, and this review is based on those discussions. It was reported that electronic monitoring and new algorithms have been devised that are providing more sensitive referral for short stature. In addition, computer programs have improved ways in which diagnoses are coded for use by various groups including healthcare providers and government health systems. Innovative cranial imaging techniques have been devised that are considered safer than using gadolinium contrast agents and are also more sensitive and accurate. Deep-learning neural networks are changing the way that bone age and bone health are assessed, which are more objective than standard methodologies. Models for prediction of growth response to growth hormone (GH) treatment are being improved by applying novel artificial intelligence methods that can identify non-linear and linear factors that relate to response, providing more accurate predictions. Determination and interpretation of insulin-like growth factor-1 (IGF-1) levels are becoming more standardized and consistent, for evaluation across different patient groups, and computer-learning models indicate that baseline IGF-1 standard deviation score is among the most important indicators of GH therapy response. While physicians involved in child growth and treatment of disorders resulting in growth failure need to be aware of, and keep abreast of, these latest developments, treatment decisions and management should continue to be based on clinical decisions. New digital technologies and advancements in the field should be aimed at improving clinical decisions, making greater standardization of assessment and facilitating patient-centered approaches.

Endocrinological features of a patient with 14q microdeletion and Dubowitz phenotype

Background

Dubowitz syndrome (DS) is a complex and rare condition characterized by postnatal growth retardation, microcephaly, short stature, mild developmental delay, facial dysmorphism, skin eruption and bone marrow failure. Though approximately 200 cases have been described so far, no specific genetic analysis, laboratory tests or radiological exams are available to confirm the diagnosis which is still based on clinical and facial features. Although short stature is a major feature of the syndrome, no endocrine alterations have been reported so far and scant data are available about the efficacy and safety of GH treatment in these patients.

Methods

A 13‐year‐old male patient was referred to our attention for short stature. Endocrinological evaluation including GH axis, adrenal and gonadal functions were assessed. aCGH was performed.

Results

14q terminal microdeletion associated with Dubowitz phenotype was found. Endocrinological investigations revealed the presence of hypopituitarism which showed a satisfactory response to short‐term growth hormone therapy. The subject also started glucocorticoid replacement therapy. Disorders in pubertal progression and gonadal function were noted.

Conclusions

Dubowitz syndrome (DS) includes different clinical findings variably occurring.

Subjects with a Dubowitz phenotype should be carefully monitored for endocrinological anomalies. The prompt recognition of potential life‐threatening endocrinological condition for example adrenal insufficiency is mandatory in order to start an adequate and early treatment.

Endocrine morbidity in midline brain defects: Differences between septo-optic dysplasia and related disorders

BACKGROUND

Septo-optic dysplasia (SOD) is a heterogeneous congenital condition. The aim of this study was to investigate the clinical phenotypes of a large cohort of children with SOD, Multiple Pituitary Hormone Deficiency (MPHD) and Optic Nerve Hypoplasia (ONH), with a focus on endocrine testing.

METHODS

Retrospective single-centre longitudinal study of children with SOD (n:171), MPHD (n:53) and ONH (n:35). SOD+ and SOD- indicate patients with or without hypopituitarism, respectively.

FINDINGS

All deficits were more frequent and occurred earlier in MPHD than SOD+ [Hazard Ratios (HR): 0·63(0·45,0·89) for GH, 0·48(0·34,0·69) for TSH, 0·55(0·38,0·80) for ACTH, 0·28(0·11,0·68) for gonadotropins], except Diabetes Insipidus (DI) [HR: 2·27(0·88,5·9)]. Severe hypothalamo-pituitary (H-P) abnormalities were more frequent in MPHD [80·0% vs 41·6%, p<0·0001 for Ectopic Posterior Pituitary (EPP)]. Stalk and PP abnormalities were associated with more severe endocrine phenotypes and placed a subgroup of SOD+ at risk of developing deficits earlier. SOD and ONH shared heterogeneous phenotypes ranging from pubertal delay to precocity and from leanness to extreme obesity, whilst MPHD had GnD and obesity only. Mortality was recorded in 4·2% (6/144) SOD and 3·2% (1/31) ONH, and only in patients with multisystem phenotypes.

INTERPRETATION

More than a single disease, SOD represents a spectrum of malformative conditions involving different brain structures and characterised by a dynamic and sequential nature of endocrine. In contrast, MPHD displays a more homogeneous phenotype of (mainly) anterior pituitary early-onset failure. Stalk and PP abnormalities place a subgroup of SOD+ at a higher risk of early-onset deficits. Additionally, there are striking differences between the SOD and MPHD cohorts in terms of pubertal progression. The shared phenotypes between ONH and SOD could be partly explained by common hypothalamic dysfunction. The differences between the cohorts are important as they may aid in planning management and preventing morbidity by dictating earlier interventions.

FUNDING

M.C., M.G., and N.I. were supported by the European Society of Paediatric Endocrinology (ESPE) through ESPE Clinical Fellowships.

Growth hormone therapy in children: predictive factors and short-term and long-term response criteria

PURPOSE

The definition of growth response in growth hormone (GH)-treated children is controversial. This study aims at: (1) evaluating short-term and long-term efficacy of GH treatment in a cohort of short children with GH deficiency (GHD); (2) assessing and compare various poor response criteria; (3) identifying predictive factors of growth response.

METHODS

Our study included 94 children, affected by isolated GHD and treated with GH until they reached final height. Criteria used for calculating the proportion of poor responders to GH for the first year were gain in height (ΔHt) SDS < 0.5 ("Bang criterion"), <0.3 or <0.4 SDS for less-severe and severe GHD, respectively ("Ranke criterion"), height velocity (HV) < mean -1 SDS ("Bakker criterion"); for adult height "Cianfarani criterion" was total ΔHt < 1 SDS.

RESULTS

After 1 year of treatment we defined "poor responders" 55.3% of patients according to Bang criterion, 40.9% according to Bakker criterion and 23.4% according to Ranke criterion. At the end of the treatment, poor responders according to Cianfarani criterion were 22.34%; almost everyone in our population (97.9%) achieved mMid-parental height (MPH). Median final Ht was -1.11 SDS. Our analysis revealed a significant negative association between ΔHt and age at diagnosis.

CONCLUSIONS

Bang criterion generated the highest number of poor responders, but had a low negative predictive value (67.5%); Ranke and Cianfarani criteria displayed similar rate of poor response. There is no reliable predictive factor of growth hormone response. However, almost all children treated reached MPH, suggesting good treatment efficacy.

Effects of milk powder intervention on bone mineral density and indicators related to bone metabolism in Chinese adolescents

The study is to determine the effects of milk powder on bone density and metabolism in healthy adolescents. Vitamin D and calcium supplements increased IGF-1 but did not affect bone mineralization or turnover. Higher vitamin D in combination with sufficient calcium supplementation in such populations requires attention.

INTRODUCTION

Both calcium and vitamin D play an important role in bone mineralization in adolescents.

METHODS

In this one and a half-year randomized controlled trial, 232 participants (aged 12-15 years) were randomly assigned to three intervention groups receiving milk powder fortified with vitamin D 400 IU plus calcium 300, or 600, or 900 mg [Ca3D (n = 54), Ca6D (n = 56), and Ca9D (n = 49)], or one control group maintaining habitual diet [control (n = 73)]. Bone turnover markers, serum intact PTH, 25(OH)D, and IGF-1 levels were measured at baseline and one and a half years, and bone mineral contents and bone areal mineral density were measured by Dual-energy X-ray absorptiometry (DXA) at baseline, one year, and one and a half years.

RESULTS

Baseline average serum 25(OH)D level and calcium intake were 29.4 nmol/L and 363.5 mg/day, respectively. There was a significant increase in bone turnover, total body, hip, lumbar spine bone mineral density (BMD), and total body BMC as well as slight fluctuations in 25(OH)D levels over one and a half years without between-group differences. Significantly decreased serum PTH level was only observed in the Ca6D group (31%, p < 0.0001), in which the intervention effect was also significant (p = 0.0029) compared with the control group. IGF-1 levels increased significantly in all intervention groups (18.5 to 22.8%, p < 0.05) but decreased in the control group (16.5%, p < 0.05), and the group by time interaction was also significant (p = 0.0029).

CONCLUSIONS

Our study showed that in healthy adolescents with low vitamin D status and calcium intake, mild vitamin D and mild to modest calcium supplements increased IGF-1 but did not affect bone mineralization or turnover. Higher vitamin D in combination with sufficient calcium supplementation in such populations requires attention.

Serum concentrations of IGF-I/IGF-II as biomarkers of alcohol damage during foetal development and diagnostic markers of Foetal Alcohol Syndrome

Foetal Alcohol Syndrome (FAS) is the most deleterious health effect derived from alcohol consumption during pregnancy and is placed at the end of the Foetal Alcohol Spectrum Disorders (FASD). Few studies have proposed potential molecular biomarkers of physical and neurological damage associated with prenatal alcohol exposure. We prospectively recruited 55 children from 8 to 12 years old, with a prenatal assessment for ethanol exposure using meconium analysis of fatty acid ethyl esters (FAEE). The control group was established for FAEE < 2 nmol/g (n = 31) and a Prenatal Ethanol Exposure (PEE) group for FAEEs > 2 nmol/g (n = 33). Moreover, 98 children adopted from Eastern European Countries (EEC) were also recruited to evaluate FASD diagnosis comprising 31 cases with complete FAS, 42 with partial FAS, 6 with ARBD and 5 with ARND. Serum values of IGF-I and IGF-II for all children recruited were determined by immunoassay. Anthropometric and neurocognitive evaluation showed severe impairments in FAS children, moderate effects in PEE and no harmful effects in the control group with no prenatal exposure to alcohol. Analysis of IGF-I and IGF-II serum concentrations revealed that FASD from EEC as well as PEE children showed significantly lower concentrations of both IGF-I and IFG-II than the control group and reference values. Moreover, Spearman correlations showed a significant effect of IGF-I on anthropometric measurements in girls, whereas IGF-II affected the neuropsychological variables in both genders. These findings validate the use of growth factors IGF-I and IGF-II as surrogate biomarkers of damage induced by prenatal exposure to ethanol and could be used in the diagnosis of foetal alcohol spectrum disorders.

Insulin-Like Growth Factors and Metabolic Syndrome in Obese Children

BACKGROUND/AIMS

Insulin-like growth factor (IGF)-I is related to cardiometabolic risk in adults, whereas the metabolic role of IGF-II is unclear. The aim of this study was to assess IGFs in obese children and correlate them with metabolic syndrome (MetS) components.

METHODS

This is a retrospective study including 574 obese children (11.34 ± 3.16 years). All subjects underwent complete anthropometry and biochemical assessment. In a subgroup of 136 subjects, body composition was evaluated. IGF-I was measured in 300 obese subjects and IGF-II in 77 obese and 15 lean children. 177 subjects were divided according to the presence of 1 or more MetS criteria: group 1, subjects with 1 MetS criterion; group 2, subjects with 2 components; and group 3, subjects with MetS diagnosis.

RESULTS

IGF-I, IGF-II, and IGF-I/insulin-like growth factor-binding protein-3 ratio were not different among subjects with an increasing number of MetS criteria and were not associated with single components of MetS as well as with body composition parameters. In children younger than 10 years, IGF-I directly correlated with high-density lipoprotein cholesterol (p < 0.005) even after controlling for confounders. IGF-II was significantly higher in obese children and correlated with parameters of insulin sensitivity (p < 0.05).

CONCLUSION

IGFs were neither related to MetS nor to body composition parameters in obese children. Further studies are needed to clarify the mechanisms underlying the relationship between IGF-II and insulin sensitivity.

IGF-1R mRNA expression is increased in obese children

OBJECTIVES

Obese children are often taller than age-matched subjects. Reports on GH and IGF-I levels in obese individuals are controversial, with normal and reduced GH-IGF-I levels having been reported in this group of patients. Thus, the aim of this study was to analyse insulin-like growth factor type 1 receptor (IGF-IR) mRNA expression in obese children.

METHODS

Forty-seven pre-pubertal children were included in this study: 29 were obese and taller than their target height, and 18 were normal eutrophic controls. Fasting blood samples were collected for IGF-IR mRNA expression in isolated lymphocytes and serum IGF-I, ALS, IGFBP-3, and IGFBP-1 concentration analysis.

RESULTS

Relative IGF-IR gene expression (2^-ΔΔCT) was significantly (P=0.025) higher in obese children (median 1.87) than in controls (1.15). Fourteen of the 29 obese subjects showed 2^-ΔΔCT values greater than or equal to 2, while only 2 individuals in the control group showed values above 2 (P=0.01). Obese children showed significantly (P=0.01) higher IGF-I concentrations than the control group (237ng/ml and 144ng/ml, respectively). Among obese patients, 65.5% had IGF-I values above the 75 percentile of the control group (P=0.02). ALS concentration was significantly (P=0.04) higher in the obese group, while IGFBP-3 levels were similar in obese and control children. IGFBP-1 concentration was lower in obese children, while insulin levels and HOMA-IR index were higher than in controls.

CONCLUSIONS

The higher IGF-IR mRNA expression observed in obese children, associated with the higher IGF-I and ALS and the lower IGFBP-1 levels, suggest that the higher stature observed in these children may be due to increased IGF-I bioactivity.

Endoscopic therapy and curative effect in pituitary adenoma patients complicated by acromegalic cardiomyopathy

The study aimed to retrospectively analyze the clinical characteristics of patients with pituitary adenomas complicated by acromegalic cardiomyopathy and to evaluate the effect of endoscopic surgery. Eighty-six pituitary adenoma patients complicated by acromegalic cardiomyopathy who were treated with endoscopic surgery in the First Affiliated Hospital of Soochow University from January 2010 to December 2016 were enrolled. We noted patient clinical characteristics and explored the relationships with surgical treatment. Before and after surgery, all patients underwent an examination of pituitary endocrinology, brain magnetic resonance (MR), and echocardiography. The serum levels of growth hormone (GH), left ventricular end-diastolic diameter (LVIDd), interventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular ejection fraction (EF), and mitral valve (E/A ratio) were examined with non-invasive methods, and the results were compared. Of the 86 patients, there were 23 with microadenomas, 27 with large adenomas, and 36 with giant adenomas. There were 28 patients with invasive adenomas and 58 with non-invasive adenomas. The pre-operative mean GH level was 71.23 ± 3.29 μg/L, which was positively correlated with tumor volume (r = 0.751, P < 0.01). Via trans-sphenoidal endoscopic pituitary adenoma resection, 51 patients underwent total tumor resections, 25 underwent subtotal resections, 8 underwent major part resections, and 2 underwent partial resections. After surgery, the GH mean level was 3.81 ± 1.03 μg/L, which was significantly different (t = 3.72, P < 0.01) from the pre-operative level. Cardiac function indices, including LVIDd, IVST, LVPWT, E/A, and EF, were significantly improved. The long-term curative rate was 39.17% and the remission rate was 77.29%. For pituitary adenoma patients complicated by acromegalic cardiomyopathy, endoscopic surgery resulted in a good curative effect and the growth hormone levels were maintained, which can significantly improve cardiac structure and function.

Assessment of insulin like growth factor-1 and IGF binding protein-3 in healthy Indian girls from Delhi and their correlation with age, pubertal status, obesity and thyroid hormonal status

BACKGROUND

Population specific data and influence of sub-clinical hypothyroidism on insulin like growth factor-1 (IGF-1) and its binding protein-3 (IGFBP-3) in Indian children is lacking. This study was undertaken to evaluate serum IGF-1 and IGFBP-3 and their correlation with age, gender, pubertal status and thyroid functions.

METHODS

A total of 840 apparently healthy school girls aged 6-18 years, were recruited for the study and underwent assessment of height, weight, body mass index, pubertal status and serum T3, T4, TSH, IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio.

RESULTS

The mean serum levels of IGF-1, IGFBP-3 levels and IGF-1/IGFBP-3 molar ratio were 381.8±240.5 ng/mL, 4.19±2.08 μg/mL and 40.5±37.2%, respectively. The serum IGF-1 and IGF-1/IGFBP-3 molar ratio increased significantly (p<0.0001) at 11 years followed by a steady yet non-significant rise till 16 years of age. A similar pattern was observed for IGFBP-3 showing a steep rise at 12 years and peaking at 16 years. Likewise, serum levels of IGF-1 and molar ratio of IGF-1/IGFBP-3 increased significantly with pubertal maturation from stage 1 to 3 and were higher in overweight girls compared to normal weight and obese girls. The growth factors were no different in girls with or without subclinical hypothyroidism.

CONCLUSIONS

There was no significant impact of age on IGF-1 and IGFBP-3 in pre-pubertal girls. A sudden marked increase at 11 years followed by a gradual rise in growth factors till 16 years is indicative of pubertal initiation and maturation. Subclinical hypothyroidism did not influence growth factors in girls.

Growth hormone excess in children with neurofibromatosis type-1 and optic glioma

In children with neurofibromatosis type 1 (NF1) and optic pathways glioma (OPG), growth hormone (GH) excess has been rarely reported and mainly associated to central precocious puberty. The aim of our study is to evaluate the prevalence of GH excess, the association with central precocious puberty, the relation with tumor site and the evolution over time in a large cohort of children with NF1 and OPG. Sixty-four NF1 children with OPG were evaluated. Patients with stature and/or height velocity >2 SD for age were studied for GH secretion. Seven out of 64 children (10.9%) with NF1 and optic pathways glioma showed GH excess, isolated in 5 cases and associated to central precocious puberty in 2. All the children with GH excess had a tumor involving the chiasma. Children with GH excess underwent medical treatment with lanreotide and a minimum clinical/biochemical follow up of 2 years is reported. The present study demonstrates that GH excess should be considered as a relative frequent endocrine manifestation in NF1 patients, similarly to central precocious puberty. Therefore, these patients should undergo frequent accurate auxologic evaluations. On the other hand, an increase in height velocity in children with NF1, even despite normal ophthalmological exams, can suggest the presence of OPG and therefore represents an indication to perform brain MRI.

Serum Insulin-like growth factor-1 levels of healthy adults in southern China

It is to establish the normal range and investigate the distribution characteristics of serum Insulin-like growth factor-1 (IGF-1) for healthy adults in southern China. IGF-1 levels of 515 healthy adults (254 males and 261 females) were measured by automated chemiluminescence immunoassay. The subjects were strictly selected healthy volunteers, aged 20 to 84 years old, with equal five year intervals and without abnormal conditions that impacted IGF-1 levels. The reference ranges were calculated using the smooth centile curves of the LMS method (L: coefficient of skewness, M: median, S: coefficient of variation). IGF-1 declined with aging in adults. There were statistically significant differences for the IGF-1 levels between men and women in some subgroups of age. Gender differences varied depending on the age. Middle-aged females had higher IGF-1 whilst elder females had lower IGF-1. The statistical differences were seen in three subgroups of age between this study and a German cohort that is the reference range for the laboratory test kit. Here, the age- and gender-specific normal range was established for Chinese adults. A Z Score of IGF-1 for an individual could be obtained via the LMSchartmaker application, which standardized IGF-1 research worldwide.

Reference ranges for an automated chemiluminescent assay for serum insulin-like growth factor I (IGF-I) in a large population of healthy adults from Buenos Aires

PURPOSE

Insulin-like growth factor I (IGF-I) represents an essential tool in the diagnostic work-up and in the monitoring of treatment efficacy for somatotrophic axis disorders both in children and adults. A large number of factors including, but not limited to, age, sex and weight as well as analytical variables influence IGF-I serum levels; therefore, reliable normative data are essential for a correct interpretation of results. The aim of the present study was to establish reference range values for serum IGF-I, in a large population of healthy adults from Buenos Aires city.

METHODS

The study included serum samples from 1044 healthy subjects aged 21-87 years (423 females and 621 males) divided into groups by sex at 5-year intervals from 21 to >75 years. Serum IGF-I concentrations were determined by a fully automated two-site, solid-phase, enzyme-labeled chemiluminescent immunometric assay (Immulite 2000, Siemens Healthcare Diagnostics). IGF-BP interferences are circumvented by blocking IGF-BP binding sites with excess IGF-II in the on-board predilution step.

RESULTS

Results show the age dependence of circulating IGF-I levels, with a smooth and steady decrease in levels with age. No sex differences were found in subjects >26 years; however, in the group aged 21-25 years, IGF-I levels were significantly higher in females. In conclusion, this study provides age- and gender-adjusted normal reference ranges for IGF-I levels obtained with an automated immunometric chemiluminescent assay Immulite 2000 in healthy adult subjects.

Early retesting by GHRH + arginine test shows normal GH response in most children with idiopathic GH deficiency

PURPOSE

Most children with idiopathic isolated GH deficiency (IGHD) normalize GH response to stimulation tests when retested at the completion of growth. The objective of this study was to test the effectiveness of early retesting in challenging the diagnosis of idiopathic IGHD and critically review the diagnostic workup leading to this diagnosis in children with short stature.

METHODS

We cross-sectionally retested 38 children with idiopathic IGHD and still on GH treatment. The initial diagnosis of idiopathic IGHD was based on subnormal GH responses to two stimulation tests and normal brain imaging or minor/nonspecific findings at magnetic resonance. The GH response normalization at retesting was considered as the main outcome measure. Clinical features of children who were falsely classified as idiopathic IGHD based on first GH testing were retrospectively analyzed.

RESULTS

GH secretion was normal in 36/38 children (95%). Two children showed slightly reduced peak GH responses and normal IGF-I levels. Fourteen children underwent GH retesting before puberty, 24 children during puberty.

CONCLUSION

The diagnostic process should be improved to minimize the rate of false positive at GH testing and, in case of unsatisfactory response to GH treatment, the diagnosis of isolated idiopathic GHD should be challenged with early retesting.

Growth hormone response to standard provocative stimuli and combined tests in very young children with Prader-Willi syndrome

BACKGROUND

In Prader-Willi syndrome (PWS) a reduced growth hormone (GH) response to several stimulators has been documented in many studies, but none have focused on very young children. We evaluated the pattern of GH secretion in very young PWS patients.

PATIENTS AND METHODS

Twenty-seven genetically confirmed PWS children (10 females, aged 0.4-5 years, mean: 2.2 ± 1.4 years) were included. All subjects underwent standard provocative tests (clonidine, CLO; and arginine, ARG) and one combined test [growth hormone-releasing hormone (GHRH) plus pyridostigmine (13 patients) or GHRH plus arginine (14 patients)]. Insulin-like growth factor-1 (IGF-1) levels were also measured.

RESULTS

While standard tests (CLO and ARG) showed low GH peak in 85.2 and 70.4% of the patients, respectively, the combined test was found to be normal in 85.2%. IGF-1 was low in 66.7% of patients. Out of 27 patients, 3 (11%) showed a normal GH peak with both standard tests (group A), 6 (22%) to one of the standard tests (group B) and 18 (67%) presented a low response to both standard tests (group C). Four subjects showed low response to both the combined and standard tests and reduced IGF-1.

CONCLUSION

Our data suggest that very young PWS children seem to have impaired hypothalamic GHRH secretion with a normal GH pituitary reserve.

Clinical features and endocrine profile of Laron syndrome in Indian children

INTRODUCTION

Patients with growth hormone (GH) insensitivity (also known as Laron syndome) have been reported from the Mediterranean region and Southern Eucador, with few case reports from India. We present here the clinical and endocrine profile of 9 children with Laron syndrome from India.

MATERIAL AND METHODS

Nine children diagnosed with Laron syndrome based on clinical features of GH deficiency and biochemical profile suggestive of GH resistance were studied over a period of 5 years from January 2008 to January 2013.

RESULTS AND DISCUSSION

Age of presentation was between 2.5-11.5 years. All children were considerably short on contemporary Indian charts with mean (SD) height Z score -5.2 (1.6). However, they were within ± 2 SD on Laron charts. No child was overweight [mean (SD) BMI Z score 0.92 (1.1)]. All children had characteristic facies of GH deficiency with an added feature of prominent eyes. Three boys had micropenis and 1 had unilateral undescended testis. All children had low IGF-1 (<5 percentile) and IGFP-3 (<0.1 percentile) with high basal and stimulated GH [Basal GH mean (SD) = 13.78 (12.75) ng/ml, 1-h stimulated GH mean (SD) = 46.29 (25.68) ng/ml]. All children showed poor response to IGF generation test.

CONCLUSION

Laron syndrome should be suspected in children with clinical features of GH deficiency, high GH levels and low IGF-1/IGFBP-3. These children are in a state of GH resistance and need IGF-1 therapy.

Association of serum components of the GH-IGFs-IGFBPs system with GHR-exon 3 polymorphism in normal and idiopathic short stature children

OBJECTIVE

To investigate the possible association of circulating components of GH-IGFs-IGFBPs system with the GHR-exon 3 genotype in normal and idiopathic short stature (ISS) children.

DESIGN

Descriptive, cross-sectional study in normal and ISS children.

SUBJECTS AND METHODS

192 normal and 81 ISS children (age: 5-17 years) were included. Serum IGF-I, IGFBP3, ALS and GHBP levels were measured. GHR-exon 3 polymorphism (GHRd3) was analyzed by multiplex PCR assay. Normal and ISS children were divided according to GHR-exon 3 genotype: homozygous for the full-length GHR isoform (GHRfl) and carriers of one or two copies of the GHRd3 allele.

RESULTS

GHRd3 genotype distribution (fl:fl/fl:d3/d3:d3,%) in normal (60:34:6) and ISS (64:32:4) was similar and reached Hardy-Weinberg equilibrium. ISS children had significantly reduced levels of GHBP and GH-dependent factors as compared to controls (p<0.0001). Within the normal group, homozygous carriers of the GHRfl allele had significantly higher GHBP serum levels than those with one or two copies of the GHRd3 allele (Mean ± SEM; GHRfl: 3.2 ± 0.2 vs GHRd3: 2.7 ± 0.2 nmol/L, p = 0.04). No other significant association with GHR exon 3 polymorphism was found in either the normal or the ISS groups.

CONCLUSIONS

GHR exon 3 polymorphism is distributed similarly in normal and ISS children, however only normal homozygous children for GHRfl allele showed higher GHBP levels. The lack of association between GHBP and GHR polymorphism in ISS children might be related to the heterogeneity of this group, where potential defects in GH receptor action may result in partial GH insensitivity.

The Challenge of Growth Hormone Deficiency Diagnosis and Treatment during the Transition from Puberty into Adulthood

In children with childhood-onset growth hormone deficiency, replacement GH therapy is effective in normalizing height during childhood and achieving adult height within the genetic target range. GH has further beneficial effects on body composition and metabolism through adult life. The transition phase, defined as the period from mid to late teens until 6-7 years after the achievement of final height, represents a crucial time for reassessing children's GH secretion and deciding whether GH therapy should be continued throughout life. Evidence-based guidelines for diagnosis and treatment of growth hormone deficient children during transition are lacking. The aim of this review is to critically review the up-to-date evidence on the best management of transition patients in order to ensure the correct definitive diagnosis and establish the appropriate therapeutic regimen.