The History of the Insulin-Like Growth Factor System.

The growth hormone (GH)-insulin-like growth factor (IGF) cascade is central to the regulation of growth and metabolism. This article focuses on the history of the components of the IGF system, with an emphasis on the peptide hormones, IGF-I and -II, their cell surface receptors, and the IGF binding proteins (IGFBPs) and IGFBP proteases that regulate the availability of the peptide hormones for interaction with their receptors in relevant target tissues. We describe landmark events in the evolution of the somatomedin hypothesis, including evidence that has become available from experiments at the molecular and cellular levels, whole animal and tissue-specific gene knockouts, studies of cancer epidemiology, identification of prismatic human cases, and short- and long-term clinical trials of IGF-I therapy in humans. In addition, this new evidence has expanded our clinical definition of GH insensitivity (GHI) beyond growth hormone receptor mutations (classic Laron syndrome) to include conditions that cause primary IGF deficiency by impacting post-receptor signal transduction, IGF production, IGF availability to interact with the IGF-I receptor (IGF-1R), and defects in the IGF-1R, itself. We also discuss the clinical aspects of IGFs, from their description as insulin-like activity, to the use of IGF-I in the diagnosis and treatment of GH deficiency, and to the use of recombinant human IGF-I for therapy of children with GHI.

A novel heterozygous STAT5B variant in a patient with short stature and partial growth hormone insensitivity (GHI).

BACKGROUND: The most frequent monogenic causes of growth hormone insensitivity (GHI) include defects in genes encoding the GH receptor itself (GHR), the signal transducer and activator of transcription (STAT5B), the insulin like-growth factor type I (IGF1) and the acid-labile subunit (IGFALS). GHI is characterized by a continuum of mild to severe post-natal growth failure. OBJECTIVE: To characterize the molecular defect in a patient with short stature and partial GHI. PATIENT AND METHODS: The boy was born at term adequate for gestational age from non-consanguineous normal-stature parents. At 2.2 years, he presented proportionate short stature (height -2.77 SDS), wide forehead and normal mental development. Whole-exome analysis and functional characterization (site-directed mutagenesis, dual luciferase reporter assay, immunofluorescence and western immunoblot) were performed. RESULTS: Biochemical and endocrinological evaluation revealed partial GH insensitivity with normal stimulated GH peak (7.8 ng/mL), undetectable IGF1 and low IGFBP3 levels. Two heterozygous variants in the GH-signaling pathway were found: a novel heterozygous STAT5B variant (c.1896G>T, p.K632N) and a hypomorphic IGFALS variant (c.1642C>T, p.R548W). Functional in vitro characterization demonstrated that p.K632N-STAT5b is an inactivating variant that impairs STAT5b activity through abolished phosphorylation. Remarkably, the patient's immunological evaluation displayed only a mild hypogammaglobulinemia, while a major characteristic of STAT5b deficient patients is severe immunodeficiency. CONCLUSIONS: We reported a novel pathogenic inactivating STAT5b variant, which may be associated with partial GH insensitivity and can present without severe immunological complications in heterozygous state. Our results contribute to expand the spectrum of phenotypes associated to GHI.

Growth Hormone Receptor Mutations Related to Individual Dwarfism.

Growth hormone (GH) promotes body growth by binding with two GH receptors (GHRs) at the cell surface. GHRs interact with Janus kinase, signal transducers, and transcription activators to stimulate metabolic effects and insulin-like growth factor (IGF) synthesis. However, process dysfunctions in the GH⁻GHR⁻IGF-1 axis cause animal dwarfism. If, during the GH process, GHR is not successfully recognized and/or bound, or GHR fails to transmit the GH signal to IGF-1, the GH dysfunction occurs. The goal of this review was to focus on the GHR mutations that lead to failures in the GH⁻GHR⁻IGF-1 signal transaction process in the dwarf phenotype. Until now, more than 90 GHR mutations relevant to human short stature (Laron syndrome and idiopathic short stature), including deletions, missense, nonsense, frameshift, and splice site mutations, and four GHR defects associated with chicken dwarfism, have been described. Among the 93 identified mutations of human GHR, 68 occur extracellularly, 13 occur in GHR introns, 10 occur intracellularly, and two occur in the transmembrane. These mutations interfere with the interaction between GH and GHRs, GHR dimerization, downstream signaling, and the expression of GHR. These mutations cause aberrant functioning in the GH-GHR-IGF-1 axis, resulting in defects in the number and diameter of muscle fibers as well as bone development.

Growth hormone receptor-deficient pigs resemble the pathophysiology of human Laron syndrome and reveal altered activation of signaling cascades in the liver.

OBJECTIVE: Laron syndrome (LS) is a rare, autosomal recessive disorder in humans caused by loss-of-function mutations of the growth hormone receptor (GHR) gene. To establish a large animal model for LS, pigs with GHR knockout (KO) mutations were generated and characterized. METHODS: CRISPR/Cas9 technology was applied to mutate exon 3 of the GHR gene in porcine zygotes. Two heterozygous founder sows with a 1-bp or 7-bp insertion in GHR exon 3 were obtained, and their heterozygous F1 offspring were intercrossed to produce GHR-KO, heterozygous GHR mutant, and wild-type pigs. Since the latter two groups were not significantly different in any parameter investigated, they were pooled as the GHR expressing control group. The characterization program included body and organ growth, body composition, endocrine and clinical-chemical parameters, as well as signaling studies in liver tissue. RESULTS: GHR-KO pigs lacked GHR and had markedly reduced serum insulin-like growth factor 1 (IGF1) levels and reduced IGF-binding protein 3 (IGFBP3) activity but increased IGFBP2 levels. Serum GH concentrations were significantly elevated compared with control pigs. GHR-KO pigs had a normal birth weight. Growth retardation became significant at the age of five weeks. At the age of six months, the body weight of GHR-KO pigs was reduced by 60% compared with controls. Most organ weights of GHR-KO pigs were reduced proportionally to body weight. However, the weights of liver, kidneys, and heart were disproportionately reduced, while the relative brain weight was almost doubled. GHR-KO pigs had a markedly increased percentage of total body fat relative to body weight and displayed transient juvenile hypoglycemia along with decreased serum triglyceride and cholesterol levels. Analysis of insulin receptor related signaling in the liver of adult fasted pigs revealed increased phosphorylation of IRS1 and PI3K. In agreement with the loss of GHR, phosphorylation of STAT5 was significantly reduced. In contrast, phosphorylation of JAK2 was significantly increased, possibly due to the increased serum leptin levels and increased hepatic leptin receptor expression and activation in GHR-KO pigs. In addition, increased mTOR phosphorylation was observed in GHR-KO liver samples, and phosphorylation studies of downstream substrates suggested the activation of mainly mTOR complex 2. CONCLUSION: GHR-KO pigs resemble the pathophysiology of LS and are an interesting model for mechanistic studies and treatment trials.

Phenotypic spectrum and responses to recombinant human IGF1 (rhIGF1) therapy in patients with homozygous intronic pseudoexon growth hormone receptor mutation.

BACKGROUND: Patients with homozygous intronic pseudoexon GH receptor (GHR) mutations (6Ψ) have growth hormone insensitivity (GHI) (growth failure, IGF1 deficiency and normal/elevated serum GH). We report 9 patients in addition to previously described 11 GHR 6Ψ patients and their responses to rhIGF1 therapy. METHODS: 20 patients (12 males, 11 families, mean age 4.0 ± 2.2 years) were diagnosed genetically in our centre. Phenotypic data and responses to rhIGF1 treatment were provided by referring clinicians. Continuous parametric variables were compared using Student t-test or ANOVA. RESULTS: 10/20 (50%) had typical facial features of GHI, 19/20 (95%) from consanguineous families and 18/20 (90%) of Pakistani origin. At diagnosis, mean height SDS: -4.1 ± 0.95, IGF1 SDS: -2.8 ± 1.4; IGFBP3 SDS: -3.0 ± 2.1 and mean basal and peak GH levels: 11.9 µg/L and 32.9 µg/L, respectively. 1/12 who had IGF1 generation test, responded (IGF1: 132-255 ng/mL). 15/20 (75%; 11M) received rhIGF1 (mean dose: 114 µg/kg twice daily, mean duration: 5.3 ± 2.5 years). Mean baseline height velocity of 4.7 ± 1.1 cm/year increased to 7.4 ± 1.8 cm/year (P = 0.001) during year 1 of therapy. Year 3 mean height SDS (-3.2 ± 1.0) was higher than pre-treatment height SDS (-4.3 ± 0.8) (P = 0.03). Mean cumulative increase in height SDS after year 5 was 1.4 ± 0.9. Difference between target height (TH) SDS and adult or latest height SDS was less than that of TH SDS and pre-treatment height SDS (2.1 ± 1.2 vs 3.0 ± 0.8; P = 0.02). CONCLUSION: In addition to phenotypic heterogeneity in the cohort, there was mismatch between clinical and biochemical features in individual patients with 6Ψ GHR mutations. rhIGF1 treatment improved height outcomes.

MECHANISMS IN ENDOCRINOLOGY: Lessons from growth hormone receptor gene-disrupted mice: are there benefits of endocrine defects?

Growth hormone (GH) is produced primarily by anterior pituitary somatotroph cells. Numerous acute human (h) GH treatment and long-term follow-up studies and extensive use of animal models of GH action have shaped the body of GH research over the past 70 years. Work on the GH receptor (R)-knockout (GHRKO) mice and results of studies on GH-resistant Laron Syndrome (LS) patients have helped define many physiological actions of GH including those dealing with metabolism, obesity, cancer, diabetes, cognition and aging/longevity. In this review, we have discussed several issues dealing with these biological effects of GH and attempt to answer the question of whether decreased GH action may be beneficial.

Brain Structure and Function Associated with Younger Adults in Growth Hormone Receptor-Deficient Humans.

Growth hormone receptor deficiency (GHRD) results in short stature, enhanced insulin sensitivity, and low circulating levels of insulin and insulin-like growth factor 1 (IGF-1). Previous studies in mice and humans suggested that GHRD has protective effects against age-related diseases, including cancer and diabetes. Whereas GHRD mice show improved age-dependent cognitive performance, the effect of GHRD on human cognition remains unknown. Using MRI, we compared brain structure, function, and connectivity between 13 people with GHRD and 12 unaffected relatives. We assessed differences in white matter microstructural integrity, hippocampal volume, subregional volumes, and cortical thickness and surface area of selected regions. We also evaluated brain activity at rest and during a hippocampal-dependent pattern separation task. The GHRD group had larger surface areas in several frontal and cingulate regions and showed trends toward larger dentate gyrus and CA1 regions of the hippocampus. They had lower mean diffusivity in the genu of the corpus callosum and the anterior thalamic tracts. The GHRD group showed enhanced cognitive performance and greater task-related activation in frontal, parietal, and hippocampal regions compared with controls. Furthermore, they had greater functional synchronicity of activity between the precuneus and the rest of the default mode network at rest. The results suggest that, compared with controls, GHRD subjects have brain structure and function that are more consistent with those observed in younger adults reported in previous studies. Further investigation may lead to improved understanding of underlying mechanisms and could contribute to the identification of treatments for age-related cognitive deficits.SIGNIFICANCE STATEMENT People and mice with growth hormone receptor deficiency (GHRD or Laron syndrome) are protected against age-related diseases including cancer and diabetes. However, in humans, it is unknown whether cognitive function and brain structure are affected by GHRD. Using MRI, we examined cognition in an Ecuadorian population with GHRD and their unaffected relatives. The GHRD group showed better memory performance than their relatives. The differences in brain structure and function that we saw between the two groups were not consistent with variations typically associated with brain deficits. This study contributes to our understanding of the connection between growth genes and brain aging in humans and provides data indicating that GHR inhibition has the potential to protect against age-dependent cognitive decline.

Effects of GH/IGF-I Axis on Retinal Vascular Morphology: Retinal Vascular Characteristics in a Clinical Setting with Severe IGF-I Deficiency.

BACKGROUND: The purpose of this study was to assess retinal vascular characteristics of patients with Laron syndrome (LS) as a genetic model of IGF-I deficiency before and after rhIGF1/IGFBP3 treatment and to compare them with healthy controls. METHODS: A total of 28 subjects (11 LS, and 17 controls) were enrolled. Patients with LS received combined rhIGF1/rhIGFBP3 1-2 mg/kg/d in a single dose and digital fundus imaging was performed. The number of branching points and tortuosity of retinal vessels were studied. Pre- and post-treatment findings were compared with each other and with controls. RESULTS: The number of branching points was significantly lower in patients with LS in comparison to controls (12.73 ± 3.41, and 17.47 ± 5.82 respectively, p = 0.012). This difference persisted after treatment (12.09 ± 2.66 post-treatment LS versus controls, p = 0.017). Tortuosity indices of nasal arteries (NA) were significantly less in LS than that of controls (upper NA 1.07 ± 0.04 and 1.12 ± 0.06 respectively p = 0.022; lower NA 1.07 ± 0.03 and 1.13 ± 0.07 respectively, p = 0.004). This difference also persisted following treatment (p < 0.05). Remaining vessels did not differ in tortuosity index. There was no significant difference of tortuosity index and number of branching points before and after treatment in patients with LS. CONCLUSION: Retinal vascular development may be adversely affected in the setting of severe IGF-I deficiency confirming a major role for GH/IGF-I axis during retinal vascular development in humans antenatally. Resolution of IGF-I deficiency following birth using rhIGF1, however, may not reverse these changes, suggesting that IGF-I may be necessary but insufficient by itself for postnatal angiogenesis.

LESSONS FROM 50 YEARS OF STUDY OF LARON SYNDROME.

OBJECTIVE: To describe the characteristics of untreated and recombinant insulin-like growth factor 1 (IGF-1)- treated patients with the Laron syndrome (LS) as seen in our clinic over a period of over 50 years. In 1966, we reported a new disease, characterized by dwarfism (-4 to -10 height standard deviation score) typical facial features, small head circumference, obesity, and small genitalia. They resembled congenital growth hormone (GH) deficiency but had high levels of serum human GH and low IGF-1. Since then, our cohort grew to 69 patients, consisting of Jews of oriental origin, Muslins, and Christians originating from the Middle East or Mediterranean area. Many belong to consanguineous families. METHODS: Molecular genetic investigations revealed that these patients had deletions or mutations in the GH receptor gene, but only individuals homozygous for this defect express the disease, coined "Laron syndrome" (LS; Online Mendelian Inheritance in Man# 262500). RESULTS: During childhood, LS patients grow slowly, have a retarded bone age and sexual development, but reach full sexual development. The treatment of LS is recombinant IGF-1, which stimulates the linear growth but increases the degree of obesity. Adult-age patients with congenital IGF-1 deficiency are protected from cancer but can develop insulin resistance, glucose intolerance, diabetes, and cardiovascular disease. Due to pathologic changes in the brain related to the type of molecular defect in the GH receptor, they vary in their intellectual capacity. A number of LS patients marry, and with help of pregestational genetic diagnosis, have healthy children. CONCLUSION: LS is a unique disease model presenting a dissociation between GH and IGF-1 activity.

Diabetes mellitus with Laron syndrome: case report.

There are different opinions concerning changes in glucose metabolism in patients with Laron syndrome. In this paper we discuss the treatment results of our patient with Laron syndrome who developed diabetes during late adolescence. A 19-year-old boy with Laron syndrome was referred to our clinic for follow-up. He had been diagnosed with Laron syndrome (LS) at 4 years old and rIGF-1 therapy was initiated. After 4 months the treatment was discontinued. At the age of 17, rIGF-1 therapy was restarted. A height gain of 8.8 cm. was observed during the 2-year treatment period. He was admitted to our hospital at the age of 19 years following discontinuation of the therapy. At that time, his height was 142 cm, and weight for height was 136%. His blood glucose was 85 mg/dL (4.72 mmol/L), insulin was 26.39 pmol/L, and HbA1c was 5.4%. At the age of 20, when he has not been receiving IGF-1 therapy for 1 year, his weight for height was 143 cm. Laboratory evaluation revealed that fasting blood glucose was 176 mg/dL (9.77 mmol/L), fasting insulin was 29.86 pmol/L, and HbA1c was 7.5%. Primary insulin therapy was then initiated. His parents both had a diagnosis of type 2 diabetes. Insulin therapy was switched to oral antidiabetic (OAD) therapy at the end of the second year because of a normal C-peptide level of 0.8 nmol/L under insulin therapy. After 6 months of OAD, HbA1c was 5.7%. The treatment was then switched to IGF-1 therapy, but his blood glucose profile was impaired and OAD therapy was restarted. In conclusion, we observed that genetic susceptibility and abdominal obesity caused type 2 diabetes in this patient. We believe that oral antidiabetic agents and life-style changes may be the appropriate approach when diabetes is developed in LS patients.

Head circumference in untreated and IGF-I treated patients with Laron syndrome: comparison with untreated and hGH-treated children with isolated growth hormone deficiency.

BACKGROUND: Head circumference (HC) is a simple and practical measure of brain size, development and longitudinal measurements of the HC in childhood are an index of brain growth. OBJECTIVE: To determine the effects of long IGF-I deficiency and treatment on HC in patients with Laron syndrome (LS). PATIENTS: 20 untreated adult LS patients, aged 48.4±11.2 years and 13 LS patients treated between ages of 5.6±4 to 11.3±3 years were studied. 15 patients with congenital IGHD treated between age 6.1±4 and 13±4 by hGH served as controls. METHODS: HC was expressed as standard deviation (SD) and Ht as SDS. HC was measured and plotted on Nellhaus charts. Linear height (Ht) was measured by a Harpenden Stadiometer. CONCLUSIONS: The mean HC deficit of the adult untreated LS males was -2.9±0.6 SD compared to a Ht deficit of -7.0±1.7 SDS. The HC of the LS adult females was -3.6±1 SD compared to a Ht SDS of -6.9±1.5 (p<0.001). IGF-I treatment (150-200 µg/kg once daily) increased the HC from -3.3±0.9 (m±SD) to normal values (0.87±1.8 SD) (p<0.001) in 11/13 children. The Ht SDS deficit decreased only by 1.5 SDS. hGH treatment of cIGHD children increased the HC from -2.0±1.8 to 0.3±1.2 SD and the Ht SDS from -4.8±1.6 to 1.6±1.0.

The emerging role of IGF-1 deficiency in cardiovascular aging: recent advances.

This review focuses on cardiovascular protective effects of insulin-like growth factor (IGF)-1, provides a landscape of molecular mechanisms involved in cardiovascular alterations in patients and animal models with congenital and adult-onset IGF-1 deficiency, and explores the link between age-related IGF-1 deficiency and the molecular, cellular, and functional changes that occur in the cardiovascular system during aging. Microvascular protection conferred by endocrine and paracrine IGF-1 signaling, its implications for the pathophysiology of cardiac failure and vascular cognitive impairment, and the role of impaired cellular stress resistance in cardiovascular aging considered here are based on emerging knowledge of the effects of IGF-1 on Nrf2-driven antioxidant response.

Diagnosis of endocrine disease: limitations of the IGF1 generation test in children with short stature.

The IGF1 generation test (IGFGT) is often used during the assessment of suspected GH insensitivity (GHI). We report the results of a survey undertaken in 2010 to determine the use of IGFGT amongst members of the European Society for Paediatric Endocrinology to evaluate suspected GHI. The literature surrounding the usefulness and limitations of IGFGT are reviewed, and recommendations provided for its use. Of 112 paediatric endocrinologists from 30 countries who responded to the survey, 91 (81%) reported that they had used the IGFGT in the previous 2 years; >10 IGFGT protocols were used. The IGFGT impacted treatment decisions for 97% of the respondents and was a prerequisite for recombinant human IGF1 treatment for 45% of respondents. From a literature review, sensitivity of the IGFGT was evaluated as 77-91% in molecularly proven cases of GHI; specificity was ≤97%, depending on the protocol. The positive predictive value of the IGFGT is likely to be low, as the frequency of normality is predictably higher than that of abnormality in GH signalling. Given the limitations of the IGFGT in the most severe cases of GHI syndrome (GHIS), the ability of the IGFGT to detect less severe GHIS is doubtful. In a pragmatic approach, the IGFGT may not be useful for the diagnosis of GHIS.

Evidence for a continuum of genetic, phenotypic, and biochemical abnormalities in children with growth hormone insensitivity.

GH insensitivity (GHI) presents in childhood as growth failure and in its severe form is associated with dysmorphic and metabolic abnormalities. GHI may be caused by genetic defects in the GH-IGF-I axis or by acquired states such as chronic illness. This article discusses the former category. The field of GHI due to mutations affecting GH action has evolved considerably since the original description of the extreme phenotype related to homozygous GH receptor (GHR) mutations over 40 yr ago. A continuum of genetic, phenotypic, and biochemical abnormalities can be defined associated with clinically relevant defects in linear growth. The role and mechanisms of the GH-IGF-I axis in normal human growth is discussed, followed by descriptions of mutations in GHR, STAT5B, PTPN11, IGF1, IGFALS, IGF1R, and GH1 defects causing bioinactive GH or anti-GH antibodies. These defects are associated with a range of genetic, clinical, and hormonal characteristics. Genetic abnormalities causing growth failure that is less severe than the extreme phenotype are emphasized, together with an analysis of height and serum IGF-I across the spectrum of different types of GHR defects. An overall view of genotype and phenotype relationships is presented, together with an updated approach to the assessment of the patient with GHI, focusing on investigation of the GH-IGF-I axis and relevant molecular studies contributing to this diagnosis.

Long-term auxological and pubertal outcome of patients with hereditary insulin-like growth factor-I deficiency (Laron and growth hormone-gene deletion syndrome) treated with recombinant human insulin-like growth factor-I.

BACKGROUND: GH-IGF-I axis is mainly involved in the complex process of somatic growth but emerging evidence suggests that it also influences hypothalamic-pituitary-gonadal (HPG) function. SUBJECTS: We report some data regarding long-term auxological and pubertal outcome of five female patients with hereditary forms of GH-IGF-I deficiency (Laron and GH-gene deletion syndrome) and a mean age of 23.4±5.3 yr (range 19-32). METHODS: All the patients received recombinant human IGF-I (rhIGF-I, Pharmacia and Upjohn, Stockholm, Sweden, and rhIGF-I, Genentech, San Francisco, CA, USA) from a mean age of 8.6 yr (range 3.2-14.2) up to the final height. RESULTS: Final height was very disappointing (≤ -5.0 SD scores) and lower than target height in all the patients. Pubertal onset was delayed in most of them but menarche occurred spontaneously in all the patients. Median age at menarche was 15.1 yr. Menstrual cycles were regular for several years. Median duration of gynecological follow- up was 8.3 yr with the longest span of 17.2 yr. CONCLUSION: We can assert that GH-IGF-I axis has an essential role in promoting linear growth in humans and its physiological action cannot be replaced by pharmacological treatment in most patients with hereditary forms of IGF-I insufficiency as demonstrated by their subnormal final height. Our clinical observations can also support an essential role of IGF-I in genitalia growth but not in the function of HPG axis as demonstrated by the maintenance of regular menstrual cycles in the presence of subnormal levels of IGF-I after treatment discontinuation.

[Hormones and hair growth]. / Hormone und Haarwachstum.

With respect to the relationship between hormones and hair growth, the role of androgens for androgenetic alopecia (AGA) and hirsutism is best acknowledged. Accordingly, therapeutic strategies that intervene in androgen metabolism have been successfully developed for treatment of these conditions. Clinical observations of hair conditions involving hormones beyond the androgen horizon have determined their role in regulation of hair growth: estrogens, prolactin, thyroid hormone, cortisone, growth hormone (GH), and melatonin. Primary GH resistance is characterized by thin hair, while acromegaly may cause hypertrichosis. Hyperprolactinemia may cause hair loss and hirsutism. Partial synchronization of the hair cycle in anagen during late pregnancy points to an estrogen effect, while aromatase inhibitors cause hair loss. Hair loss in a causal relationship to thyroid disorders is well documented. In contrast to AGA, senescent alopecia affects the hair in a diffuse manner. The question arises, whether the hypothesis that a causal relationship exists between the age-related reduction of circulating hormones and organ function also applies to hair and the aging of hair.

NREM sleep architecture and relation to GH/IGF-1 axis in Laron syndrome.

BACKGROUND: Laron syndrome (LS), known as growth hormone (GH) receptor deficiency, is a rare form of inherited GH resistance. Sleep disorders were described as a common feature of adult LS patients, while no data are available in children. Bi-directional interactions between human sleep and the somatotropic system were previously described, mainly between slow wave sleep and the nocturnal GH surge. AIMS: To analyze the sleep macro- and microstructure in LS and to evaluate the influence of substitutive insulin-like growth factor 1 (IGF-1) therapy on it. METHODS: Two young LS females underwent polysomnography; the first study was performed during IGF-1 therapy, the second one after a 3-month wash-out period. RESULTS: In both patients, the sleep macrostructure showed that time in bed, sleep period time, total sleep time, sleep efficiency and rapid eye movement (REM) percentage were all increased during wash-out. The sleep microstructure (cyclic alternating pattern: CAP) showed significantly higher EEG slow oscillations (A1%) in NREM sleep, both during IGF-1 therapy and wash-out. CONCLUSIONS: Sleep macrostructure in LS children is slightly affected by substitutive IGF-1 therapy. Sleep microstructure shows an increase of A1%, probably related to abnormally high hypothalamic GHRH secretion, due to GH insensitivity.

Insulin-like growth factor-I treatment in primary growth hormone insensitivity: effect of recombinant human IGF-I (rhIGF-I) and rhIGF-I/rhIGF-binding protein-3 complex.

BACKGROUND/AIMS: Growth hormone insensitivity syndrome (GHIS) is a rare cause of growth retardation characterized by high serum GH levels, and low serum insulin-like growth factor I (IGF-I) levels associated with a genetic defect of the GH receptor (GHR) as well post-GHR signaling pathway. Based on clinical, as well as biochemical characteristics, GHIS can be genetically classified as classical/Laron's syndrome and nonclassical/atypical GHIS. Recombinant human IGF-I (rhIGF-I) treatment is effective in promoting growth in subjects who have GHIS. Further, pharmacological studies of a IGF-I compound containing a 1:1 molar complex of rhIGF-I and rhIGF-binding protein-3 (BP-3) demonstrated that the complex was effective in increasing levels of circulating total and free IGF-I and that the administration in patients with GHIS should be safe, well-tolerated and more effective than rhIGF-I on its own. PATIENT/METHODS: We describe the long-term effect of various IGF-I preparations (rhIGF; rhIGF-I/rhIGFBP-3) in a single subject treated for more than 14 years while focusing on height, height velocity as well as on additional auxological and laboratory data. RESULTS: This study confirms that rhIGF-I is effective in promoting growth in children with GHIS. However, on the combined rhIGF-I/rhIGFBP-3 treatment as well as off rhIGF-I therapy the height velocity decreased drastically (2 and 1.8 cm vs. overall 6.5 cm/year on rhIGF-I, respectively). On rhIGF-I treatment, serum IGF-I was found to be well within the normal range, whereas serum IGFBP-3 remained low. On the rhIGF-I/rhIGFBP-3 compound therapy, however, serum IGFBP-3 increased into the normal range, which was not the case for serum IGF-I. Importantly, the increase of the serum IGFBP-3 level excludes noncompliance. In addition, body mass index as well as dual-energy X-ray absorptiometry analysis underlined the positive effect of rhIGF-I treatment on body composition. CONCLUSIONS: The rhIGF-I/rhIGFBP-3 compound therapy seems to be not efficient in treating this individual patient with GHIS when compared with rhIGF-I alone.

Hand size and growth in untreated and IGF-I treated patients with Laron syndrome.

UNLABELLED: We have previously reported on the linear growth, growth of the head circumference and foot length in untreated and IGF-I treated patients with Laron syndrome (LS) (primary GH insensitivity). AIM: To assess the size and growth of the hands in patients with LS from early childhood to adult age. PATIENTS: Ten IGF-I treated children with LS (4 M, 6 F) and 24 untreated patients (10 M, 14 F) were studied. METHODS: Measurements of palm length were made on available standardized hand X-rays from infancy to adult age. The measurements were compared to normal references and SD values were calculated for each measurement. The growth of the hand was compared to the concomitant height of the body. RESULTS: Hand SDS in untreated patients with LS decreased with age, from a mean of -2.8 +/- 0.7 (age 1-3 years) to -7.3 +/- 0.8 (age 13-15 years) and to -9.0 +/- 3.9 (age 40-50 years). During 9 years of IGF-I treatment the hand size deficit SDS did not improve in contradistinction to the height SDS which decreased from -6.2 +/- 1.2 to -3.9 +/- 0.5. CONCLUSION: Congenital IGF-I deficiency, as in Laron syndrome, profoundly affects the size and growth of the hand as part of its growth retardation characteristics, resulting in acromicria.