Fasting gut hormone levels change with modest weight loss in obese adolescents.

BACKGROUND: Gut hormones change with weight loss in adults but are not well studied in obese youth. OBJECTIVE: The primary aim was to evaluate how gut hormones and subjective appetite measure change with dietary weight loss in obese adolescents. METHODS: Participants were a subset of those taking part in the 'Eat Smart Study'. They were aged 10-17 years with body mass index (BMI) > 90th centile and were randomized to one of three groups: wait-listed control, structured reduced carbohydrate or structured low-fat dietary intervention for 12 weeks. Outcomes were fasting glucose, insulin, leptin, adiponectin, total amylin, acylated ghrelin, active glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide (GIP), pancreatic polypeptide (PP) and total peptide tyrosine-tyrosine. Pre- and postprandial subjective sensations of appetite were assessed using visual analogue scales. RESULTS: Of 87 'Eat Smart' participants, 74 participated in this sub-study. The mean (standard deviation) BMI z-score was 2.1 (0.4) in the intervention groups at week 12 compared with 2.2 (0.4) in the control group. Fasting insulin (P = 0.05) and leptin (P = 0.03) levels decreased, while adiponectin levels increased (P = 0.05) in the intervention groups compared with control. The intervention groups were not significantly different from each other. A decrease in BMI z-score at week 12 was associated with decreased fasting insulin (P < 0.001), homeostatic model of assessment-insulin resistance (P < 0.001), leptin (P < 0.001), total amylin (P = 0.03), GIP (P = 0.01), PP (P = 0.02) and increased adiponectin (P < 0.001). There was no significant difference in appetite sensations. CONCLUSIONS: Modest weight loss in obese adolescents leads to changes in some adipokines and gut hormones that may favour weight regain.

Identification and localization of insulin-like growth factor-binding protein (IGFBP) messenger RNAs in human hair follicle dermal papilla.

The role of the insulin-like growth factors (IGFs) in hair follicle biology has recently been recognized, although their actions, sites of production, and modulation by the insulin-like growth factor-binding proteins (IGFBPs) have not to date been defined. IGF-I is essential for normal hair growth and development, and may be important in regulation of the hair growth cycle. In many culture systems, IGF-I actions are modulated by the IGFBPs. Thus, if IGFBPs are produced in the human hair follicle, they may play a role in targeting IGF-I to its receptor or may modulate IGF-I action by interaction with matrix proteins. We have used in situ hybridization to localize messenger RNA for the six IGFBPs in anagen hair follicles. Anti-sense and sense RNA probes for the IGFBPs (IGFBP-1 to -6) were produced, and 5-micrometer sections of adult facial skin were probed. Messenger RNA for IGFBP-3, -4, and -5 were identified, with predominantly IGFBP-3 and -5 mRNA found in the dermal papilla, and to a lesser extent IGFBP-4 mRNA. IGFBP-4 mRNA was also found at the dermal papilla/epithelial matrix border. Messenger RNAs for both IGFBP-4 and -5 were also demonstrated in the dermal sheath surrounding the hair follicle. Messenger RNAs for IGFBP-1, -2, and -6 were not identified. These studies demonstrate specific localization of IGFBP mRNAs in hair follicles, suggesting that they each play specific roles in the local modulation of IGF action during the hair growth cycle.

Abnormal regulation of insulin-like growth factor binding proteins in adolescents with insulin-dependent diabetes.

We have measured fasting 0800 h insulin-like growth factor binding proteins (IGFBP)-1 and IGFBP-3, in 52 diabetic adolescents and 74 puberty-matched control subjects with short stature and normal hormonal status. We have also measured overnight hourly profiles of IGFBP-1, glucose, free insulin, and GH in 12 of the diabetic adolescents. With advancing age and pubertal status, IGFBP-1 declined and IGFBP-3 increased significantly in the control, but not the diabetic group. Fasting IGFBP-1 levels were elevated 4-fold compared to controls. Median IGFBP-3 was significantly lower in the diabetic compared to the control group in pubertal stages III and V. Elevated IGFBP-1 was significantly correlated with metabolic control in poorly controlled subjects (mean 12-month glycosylated haemoglobin greater than 8.5%). In the overnight profiles, mean hourly IGFBP-1 was inversely related to insulin, but not glucose. As free insulin levels declined, IGFBP-1 rose, associated with rising predawn blood sugars. The integrated 3-h IGFBP-1 value (0500-0800 h) was significantly correlated with the corresponding glucose integrated value. IGFBP-1 area under the curve for the whole overnight profile was significantly correlated with glycosylated hemoglobin in 11 of the 12 subjects. IGFBP-1 from diabetic adolescents has been shown to inhibit IGF-I bioactivity. We postulate that IGFBP-1 may have a role in growth impairment of poorly controlled diabetes and may contribute to the dawn phenomenon.

Localization of messenger ribonucleic acid for insulin-like growth factor-binding proteins in human skin by in situ hybridization.

The role of the insulin-like growth factors (IGFs) in human skin physiology has been increasingly recognized, although relatively little is known about the cell types involved or the cellular mechanisms that mediate these responses. Epidermal keratinocytes and dermal fibroblasts both possess IGF-I receptors and are responsive to IGF-I. IGF-binding proteins (IGFBPs), known modulators of IGF action, may also be responsible for targeting IGF-I to its receptors and are produced by both cultured keratinocytes and fibroblasts. To demonstrate sites of production of IGFBPs in human skin, we have used in situ hybridization to localize messenger ribonucleic acid (mRNA) for the six IGFBPs. Antisense and sense RNA probes for the IGFBPs (IGFBP-1 to -6) were produced, and 5-microns sections of normal adult human male chest skin were probed. The control probe used was keratin-5, which is known to hybridize to the basal keratinocytes of the epidermis. mRNAs for human IGFBP-2, -3, -4, and -5 were identified, with mRNAs for IGFBP-2 and IGFBP-4 localized in sebaceous glands and eccrine sweat glands (epidermal origin), IGFBP-3 mRNA in the basal layer of the epidermis and mRNAs for IGFBP-4, and IGFBP-5 found throughout the dermis. mRNAs for IGFBP-1 and -6 were not identified in human skin. These studies demonstrate specific localization of IGFBP mRNAs in adult human skin, suggesting that each IGFBP may play a specific role in targeting IGF-I to its receptor on responsive cells and, ultimately, in modulation of IGF-I action in skin.

Expression of SHOX in human fetal and childhood growth plate.

Abnormalities in the growth plate may lead to short stature and skeletal deformity including Leri Weil syndrome, which has been shown to result from deletions or mutations in the SHOX gene, a homeobox gene located at the pseudoautosomal region of the X and Y chromosome. We studied the expression of SHOX protein, by immunohistochemistry, in human fetal and childhood growth plates and mRNA by in situ hybridization in childhood normal and Leri Weil growth plate. SHOX protein was found in reserve, proliferative, and hypertrophic zones of fetal growth plate from 12 wk to term and childhood control and Leri Weil growth plates. The pattern of immunostaining in the proliferative zone of childhood growth plate was patchy, with more intense uniform immunostaining in the hypertrophic zone. In situ hybridization studies of childhood growth plate demonstrated SHOX mRNA expression throughout the growth plate. No difference in the pattern of SHOX protein or mRNA expression was seen between the control and Leri Weil growth plate. These findings suggest that SHOX plays a role in chondrocyte function in the growth plate.

Localization of mRNAs for insulin-like growth factor-I (IGF-I), IGF-I receptor, and IGF binding proteins in rat eye.

PURPOSE: To localize mRNAs for insulin-like growth factor (IGF)-I, IGF-I receptor (IGF-IR), and IGF binding protein (BP)-1 to IGFBP-6 in the rat eye. METHODS: cDNA sequences for IGF-I, IGF-IR, and IGFBP-1 to IGFBP-6 were used to synthesize 35S-CTP labeled antisense and sense probes for in situ hybridization on 5-microns sections of the rat eye, including the retina, choroid, sclera, ciliary body, and cornea. RESULTS: IGF-I mRNA was demonstrated over ganglion cells of the retina and endothelial cells of the choroid and ciliary processes. IGF-IR mRNA showed more extensive distribution, localizing to the retinal ganglion cell layer, inner nuclear layer, and outer limiting membrane and also the outer nonpigmented epithelium of the ciliary processes and cornea, conjunctiva, and lens. IGFBP-2 mRNA localized to outer nonpigmented epithelia of the ciliary processes and the germinal layer of corneal epithelium as well as iris, conjunctiva, and sclera. Messenger RNAs for IGFBP-3 to IGFBP-6 localized to choroidal endothelial cells and chromatophores and also to the inner pigmented epithelium of the ciliary processes. Messenger RNAs for IGFBP-5 and IGFBP-6 were seen in the inner and outer nuclear layers of the neural retina. IGFBP-1 mRNA was not detected within the rat eye. CONCLUSIONS: Using in situ hybridization, we have demonstrated mRNAs for IGF-I, IGF-IR, and IGFBP-2 to IGFBP-6 in specific histologic layers of the retina, choroid, ciliary body, and cornea in the rat. The characterization of the IGF system in vivo suggests specific roles in the normal eye and provides a basis for studying the IGF system in eye pathology.

Localization of Insulin-Like Growth Factor-II Receptors in Rat Brain by in vitro Autoradiography and Immunohistochemistry.

Insulin-like growth factor-ll (IGF-II) and its receptor, which is homologous with the mannose-6-phosphate (M6P) receptor, are found in high levels in adult rat and human brain, though their role remains unclear. In order to point to possible regional functions, we have mapped and quantified IGF-II/M6P receptors in sagittal sections of adult rat brain by in vitro autoradiography/computerized densitometry and immunohistochemistry. While in vitro autoradiography allowed mapping and quantitation, immunohistochemistry both confirmed mapping and allowed more detailed determination of cellular distribution of receptors. The two methods were generally in agreement with few areas of mismatching. By in vitro autoradiography, a discrete and characteristic distribution of IGF-II receptor binding was demonstrated, with specific binding representing 85% of total binding. Displacement and specificity competition curves in arcuate nucleus and choroid plexus were typical for authentic IGF-II receptors with half maximal displacement at 1 nM cold IGF-II. IGF-II receptor density, estimated by in vitro autoradiography, was very high in circumventricular organs, especially the median eminence, which had the highest binding in the brain. In the remainder of the brain there was concordance between the distribution of receptors identified by the two techniques, with greatest densities in the olfactory bulb and olfactory pathways, the hippocampus and discrete regions of the cerebral cortex, cerebellum, hypothalamus, thalamus and brainstem. There were however, some notable mismatches. Autoradiographic binding was high to very high in the median eminence, arcuate nucleus, suprachiasmatic nucleus and anterodorsal thalamic nucleus, whereas these areas were only poorly immunostained. Conversely, the septum showed moderate autoradiographic binding, but very prominent immunostaining of neurons in its dorsolat-eral aspect. Using the immunohistochemical technique IGF-II receptors were localized to specific neuronal groups such as the mitral cells of the olfactory bulb, Purkinje cells of the cerebellum and neurons in the red nucleus. Fibre pathways were not labelled by either technique. We conclude that IGF-II/M6P receptors are widespread throughout rat brain, specifically in neurons and blood vessels, with a similar, but distinct distribution to IGF-I and insulin receptors. Many of these regions have in common high rates of metabolic and synthetic activity, which may be mediated by IGF-II/M6P and their receptors.

Localization studies of IGFBP-2 and IGFBP-5 in the anterior compartment of the eye.

PURPOSE: Insulin-like growth factor binding proteins (IGFBPs) may modulate insulin-like growth factor-I (IGF-I) action and are important regulating factors in the IGF system. Our aim was to determine the presence of IGFBP-2 and -5 in the anterior compartment of the eye and to compare the histological sites of these IGFBP proteins with the respective IGFBP mRNAs. METHODS: To investigate this, immunohistochemistry was used to detect the presence of IGFBP-2 and -5 proteins, and in situ hybridization was used to determine the presence of IGFBP-2 and -5 mRNAs. The studies were performed in normal adult male Sprague-Dawley rats. Immunohistochemistry was performed by the immunoperoxidase method with polyclonal antibovine-IGFBP-2 and antihuman-IGFBP-5 antibodies. In situ hybridization was performed using 35S-radiolabelled riboprobes. RESULTS: IGFBP-2 mRNA and protein were demonstrated in the outer non-pigmented ciliary epithelium, the corneal germinal epithelium and the corneal endothelium. IGFBP-2 mRNA was detected in these same histological layers of the ciliary processes and the cornea. IGFBP-5 mRNA localized to the stroma and also to the inner pigmented ciliary epithelium and IGFBP-5 protein was demonstrated in the adjacent outer nonpigmented ciliary epithelium. IGFBP-5 mRNA and protein were not demonstrated in the cornea. IGFBPs-2 and -5 were not demonstrated by immunohistochemistry in other structures of the eye. CONCLUSION: We have shown co-localization of IGFBP-2 mRNA and protein and adjacent cellular localization of IGFBP-5 mRNA and proteins in the anterior compartment of the eye. The presence of IGFBP-2 and -5 in the outer ciliary epithelium suggests secretion into the aqueous humour, where they may enhance trapping of IGF-1 which may be important for lens and corneal cell survival. Our studies outlining the site of locally synthesized IGFBPs suggests specific roles in regulation of IGFs and highlights the potential importance of the IGF system in the eye.

Maturity-onset diabetes of the young (MODY): three case reports and new perspectives.

Maturity-onset diabetes of the young (MODY) is a rare form of juvenile diabetes mellitus that presents with hyperglycaemia in the absence of ketosis. We present three cases of MODY, all of whom had pedigrees with diabetics in multiple generations. All our patients presented in adolescence with evidence of insulin resistance. Two patients were relatively overweight. All three patients were readily controlled on diet alone. None had any clinical evidence of diabetic complications in early adulthood. Recently there has been a marked increase in our understanding of MODY. Genetic linkage and mutational analyses have identified three subtypes (MODY1, 2 and 3) that are all transmitted in an autosomal dominant fashion. The pathophysiology of the MODY subtypes is variable with both increased and decreased insulin levels being seen. A failure to recognise MODY will result in a lack of appropriate therapy and the potential for diabetic complications.

Thyroid nodules in childhood and adolescence--thirty years of experience.

In the thirty year period between 1966 and 1996, fifty-two patients underwent surgery for thyroid nodules at the Royal Children's Hospital, Melbourne. We aimed to review their presentation, investigation, histology, treatment and to follow up those who had malignant neoplasms. Forty-one of the fifty-two patients presented with a single thyroid nodule. Investigations performed included thyroid function tests (N = 32), thyroid autoantibodies (N = 21), an ultrasound of the thyroid (N = 26) and 99mTechnetium scanning (N = 32). Thirty-five of the neoplasms were benign, the follicular adenoma (N = 16) being the most common. Seventeen patients had malignant neoplasms, seven of whom had papillary and seven of whom had follicular carcinoma. Three patients had medullary carcinoma of the thyroid. Nine of the seventeen patients with thyroid malignancy received post-operative 131I treatment. At the time of this review, all patients were living.

Reversible cardiomyopathy in paediatric Addison's disease--a cautionary tale.

A 13 year-old girl with clinical features of Addison's disease developed acute cardiac failure after initiation of treatment and after initial clinical improvement. Large doses of i.v. hydrocortisone and oral fludrocortisone, in addition to inotropic and ventilatory support, were required to achieve cardiovascular stability. The cardiomyopathy improved over one week and her condition then remained stable on oral glucocorticoid and mineralocorticoid replacement therapy. Reversible cardiomyopathy is a rare and potentially life-threatening complication of Addison's disease. The second reported paediatric patient is presented, the only one reported to require ventilatory support.

Effect of 24 months of recombinant growth hormone on height and body proportions in SHOX haploinsufficiency.

Leri-Weill syndrome (LWS) is a skeletal dysplasia with mesomelic short stature, bilateral Madelung deformity (BMD) and SHOX (short stature homeobox-containing gene) haploinsufficiency. The effect of 24 months of recombinant human growth hormone (rhGH) therapy on the stature and BMD of two females with SHOX haploinsufficiency (demonstrated by fluorescence in situ hybridisation) and LWS was evaluated. Both patients demonstrated an increase in height standard deviation score (SDS) and height velocity SDS over the 24 months of therapy. Patient 1 demonstrated a relative increase in arm-span and upper segment measurements with rhGH while patient 2 demonstrated a relative increase in lower limb length. There was appropriate advancement of bone age, no adverse events and no significant deterioration in BMD. In this study, 24 months of rhGH was a safe and effective therapy for the disproportionate short stature of SHOX haploinsufficiency, with no clinical deterioration of BMD.

Familial growth and skeletal features associated with SHOX haploinsufficiency.

This study was designed to determine the intrafamilial effect of SHOX haploinsufficiency on stature, by comparing the growth and phenotype of 26 SHOX haploinsufficient individuals with 45 relatives and population standards. It confirmed that SHOX haploinsufficiency leads to growth restriction from birth to final height. Compared to unaffected siblings, the SHOX haploinsufficient cohort was 2.14 SDS (3.8 cm) shorter at birth and 2.1 SDS shorter through childhood. At final height females were 2.4 SDS (14.4 cm) shorter and males 0.8 SDS (5.3 cm) shorter than normal siblings. The family height analysis suggests that the effect of SHOX haploinsufficiency on growth may have been previously underestimated at birth and overestimated in males at final height. SHOX haploinsufficiency leads to short arms in 92%, bilateral Madelung deformity in 73% and short stature in 54%. Females were more severely affected than males. We conclude that SHOX is a major growth gene and that mutations are associated with a broad range of phenotype.

Histopathological analysis of Leri-Weill dyschondrosteosis: disordered growth plate.

Leri-Weill syndrome (LWS) is a dominant (pseudoautosomal) skeletal dysplasia with mesomelic short stature and bilateral Madelung deformity, due to dyschondrosteosis of the distal radius. It results from the loss of one copy of the Short Stature Homeobox Gene (SHOX) from the tip of the short arm of the X or Y chromosome. SHOX molecular testing enabled us to evaluate the histopathology of the radial physis in LWS patients with a documented SHOX abnormality. A widespread disorganisation of physeal anatomy was revealed with disruption of the normal parallel columnar arrangement of chondrocytes. Tandem stacking of maturing chondrocytes within columns was replaced by a side-by-side arrangement. The presence of hypertrophic osteoid with micro-enchondromata in the radial metaphysis suggests abnormal endochondral ossification. The Vickers' ligament was confirmed to blend with the triangular fibrocartilage complex (TFCC). This histopathological study demonstrates that the zone of dyschondrosteosis in LWS is characterised by marked disruption of normal physeal chondrocyte processes and that a generalised physeal abnormality is present.

Potential adverse endocrine effects of inhaled corticosteroids.

Evidence exists for a potential role for inhaled corticosteroids, particularly when used in high dose to cause growth impairment, delayed maturation and adrenal suppression in children adolescents with asthma. The functional significance of biochemical adrenal suppression remains uncertain. Similarly, there is as yet insufficient evidence to determine whether inhaled corticosteroids may adversely affect bone mineral density in children and adolescents with asthma.

Aberrant cervical thymus mimicking a cervical mass.

A case of a 9-year-old female with suprasternal extension of the thymus mimicking thyroid gland enlargement is described. Ultrasonography successfully established the diagnosis. Aberrant cervical thymic tissue is an infrequently reported cause of paediatric neck masses. It is important to be aware of this entity to prevent anxiety and inappropriate investigation and/or intervention.

Oral glucose tolerance test in children and adolescents: positives and pitfalls.

OBJECTIVES: To describe the glycaemic status (assessed by an oral glucose tolerance test (OGTT)) and associated comorbidities in a cohort of Australian children and adolescents at risk of insulin resistance and impaired glucose homeostasis (IGH). METHODS: Twenty-one children and adolescents (three male, 18 female) (18 Caucasian, one Indigenous, two Asian) (20 obese, one lipodystrophy) referred to the Paediatric Endocrinology and Diabetes Clinic underwent a 2-h OGTT with plasma glucose and insulin measured at baseline, + 60 and + 120 min. If abnormal, the OGTT was repeated. RESULTS: The mean (SD) age was 14.2 (1.6) years, BMI 38.8 (7.0) kg/m2 and BMI-SDS 3.6 (0.6). Fourteen patients had fasting insulin levels >21 mU/L. Type 2 diabetes mellitus was diagnosed in one patient, impaired glucose tolerance (IGT) in four patients and impaired fasting glycaemia (IFG) in one patient. Despite no weight loss, only one patient had a persistently abnormal OGTT on repeat testing. Three patients with IGH were medicated with risperidone at the time of the initial OGTT. One patient who had persistent IGT had continued risperidone. The other two patients had initial OGTT results of IGT and diabetes mellitus type 2. They both ceased risperidone between tests and repeat OGTT showed normal glycaemic status. CONCLUSIONS: Use of fasting glucose alone may miss cases of IGH. Diagnosis of IGT should not be made on one test alone. Interpretation of glucose and insulin responses in young people is limited by lack of normative data. Larger studies are needed to generate Australian screening recommendations. Further assessment of the potential adverse effects of atypical antipsychotic medication on glucose homeostasis in this at-risk group is important.

Changes in growth hormone concentrations during puberty in adolescents with insulin dependent diabetes.

OBJECTIVE: To document the changes in pulsatile growth hormone secretion in diabetic adolescents during puberty, and to investigate their relationship to both metabolic control and stature. DESIGN: Auxological parameters, overnight growth hormone secretion, fasting IGF-I, hourly glucose and metabolic control were assessed in a group of adolescents with diabetes. PATIENTS: Fifty-two diabetic adolescents (28 males and 24 females) at different pubertal stages and with varying degrees of metabolic control were studied. Ten of those with poor diabetic control were studied on two occasions. MEASUREMENTS: Height and weight measurements, pubertal staging, growth velocity data and bone age estimation were obtained on all the patients. Overnight growth hormone profiles (Pulsar program analysis), glycosylated haemoglobin and fasting IGF-I were performed on all the subjects. Hourly overnight glucose measurements were also obtained on the ten subjects who had two overnight growth hormone studies. RESULTS: For the whole diabetic growth, GH area under curve (AUC) was maximal in late puberty (pubertal stage 4), and was paralleled by maximal GH peak amplitude. No relationship between GH-AUC and metabolic control was demonstrated. No difference in GH parameters was demonstrated between the male and female subgroups. The relationship between growth hormone secretory parameters and stature was not significant. However, GH-AUC was significantly correlated with growth velocity in the males but not the females. CONCLUSIONS: The pattern of GH secretion in adolescents with diabetes parallels that seen in normal adolescents during puberty, with increases in GH concentration associated with increased GH pulse amplitude. The degree of metabolic control had no effect on this pattern and there was no relationship between GH secretory parameters and stature.