Endocrine and metabolic complications in children and adolescents with Sickle Cell Disease: an Italian cohort study.

BACKGROUND: Children with Sickle Cell Disease (SCD) show endocrine complications and metabolic alterations. The physiopathology of these conditions is not completely understood: iron overload due to chronic transfusions, ischemic damage, and inflammatory state related to vaso-occlusive crises may be involved. Aims of this study were to evaluate the growth pattern, endocrine complications, and metabolic alterations and to detect the relationship between these conditions and the SCD severity in affected children and adolescents. METHODS: Fifty-two children and adolescents with SCD [38 homozygous sickle hemoglobin (HbSS) and 14 heterozygous sickle hemoglobin (HbSC); age range 3-18 years] were recruited. Anthropometric [height, body mass index (BMI), arm span, sitting height, target height (TH), and pubertal status] and laboratory [blood cell counts, hemolysis indices, metabolic and nutritional status indices and hormonal blood levels] data were evaluated. The SCD severity was defined according to hematological and clinical parameters. RESULTS: Height-SDS adjusted for TH and BMI-SDS were significantly higher in HbSC children than in HbSS ones. Forty-eight out of 52 patients (92%) had at least one metabolic and/or endocrine alteration: insufficiency/deficiency of vitamin D (84.7%), insulin resistance (11.5%), growth hormone deficiency (3.8%), subclinical hypothyroidism (3.8%), and hypogonadism (1.9%). Levels of vitamin D were significantly and negatively correlated with clinical indicators of the SCD severity. Subjects with HbSS genotype show significant lower levels of both insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein 3 than children with HbSC. In the study population IGF-1 values were significantly and positively correlated with Hb and negatively with lactate dehydrogenase. CONCLUSIONS: Metabolic alterations and endocrine complications are very common in children and adolescents with SCD. A regular follow-up is necessary to identify subjects at risk for complications to precociously start an appropriate treatment and to improve the quality of life of SCD patients.

Interactions among pro-inflammatory cytokines, IGF system and thyroid function in pre-pubertal obese subjects.

Obesity is a state of chronic inflammation. Data on IGF system are often discrepant, and their relationships with mediators of inflammation are unknown. Furthermore, changes in thyroid function have been reported. We aimed at investigating the changes in these systems, and verify any relationships among cytokines, IGF system, thyroid function and insulin-insensitivity. Fifty obese pre-pubertal children, and 55 normal-weight subjects comparable for age and sex were enrolled. Serum IGF-I, IGF-II, IGFBP-1, IGFBP-2, IGFBP-3, IL-6 and TNF-alpha were assayed. In obese children insulin, TSH and FT4 were measured also, and the HOMA-IR index was calculated. Increased IGF-II, IL-6 and TNF-alpha, and decreased IGFBP-1 and IGFBP-2 concentrations were found in obese compared to normal-weight children. The IGF-I/IGFBP-3 molar ratio was also reduced in the obese subjects. In the obese children with high HOMA-IR index, IGFBP-1 and -2 serum concentrations were significantly decreased compared with those with normal insulin sensitivity, and in the obese subjects with increased TSH, IGFBP-2 concentrations were lower, and IGFBP-3 levels were higher compared to their counterparts with normal TSH levels. Among the significant correlations, BMISDS was correlated with IGF-II, and TSH. IGF-II concentrations showed a positive relationship with IL-6. TSH was correlated with IGFBP-2 also. The data showed interactions among IL-6, IGF system, insulin sensitivity, and thyroid function with changes being related to the degree of obesity. Chronic inflammation in obese children was confirmed. Some of the changes in the IGF system could be a consequence of insulin resistance and could account also for later complications in obese subjects.

Plasma brain-derived neurotrophic factor concentrations in children and adolescents.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is a mediator of neuronal plasticity influencing learning, memory and cognitive behavior. The aim of this study is to assess plasma BDNF variations according to pubertal status. METHODS: A total of 110 subjects were included in the study. Blood samples were collected after overnight fasting. Plasma BDNF concentrations were measured by enzyme-linked immunosorbent assay. Gonadotrophins, sex steroids, and IGF-1 were also assessed. RESULTS: BDNF was positively correlated with platelet count and negatively associated with both BMI and age. BDNF levels in pubertal males were significantly lower than prepubertal males and both prepubertal and pubertal females. CONCLUSIONS: Plasma BDNF levels seem to be influenced by hormonal status. We demonstrate that parameters such as age or gender have a specific impact on stored and circulating BDNF blood levels and platelets remain the most important predictor of their concentration. Further studies are necessary to better understand the role of this neurotrophin in pubertal development.

Allopregnanolone levels decrease after gonadotropin-releasing hormone analog stimulation test in girls with central precocious puberty.

BACKGROUND: Allopregnanolone, a neuroactive steroid mainly secreted by adrenals and gonads, is a hormone that seems to play a role in precocious puberty, as demonstrated by its high baseline levels found in girls with central precocious puberty (CPP). Allopregnanolone concentrations significantly increase after GnRH and ACTH stimulation test suggesting both its ovarian and adrenal production. AIM: Aim of this study was to evaluate allopregnanolone concentrations after GnRH and GnRH agonist analog stimulation test in girls with CPP to better establish its secretion source. SUBJECTS AND METHODS: Gonadotropins and steroid hormones were evaluated in different days after GnRH and triptorelin stimulation test in 15 CPP girls. RESULTS: After GnRH stimulation, LH, FSH, and allopregnanolone concentrations significantly increased (p<0.05). After triptorelin administration LH, FSH, estradiol and DHEAS levels significantly increased (p<0.05), while allopregnanolone concentrations significantly decreased (1.08±0.24 vs 0.87±0.28 nmol/l; p=0.003). CONCLUSIONS: The different response of allopregnanolone to GnRH and GnRH agonist analog might reflect the agonist and antagonist action exerted by these secretagogues. Our data suggest the prevalent gonadal allopregnanolone production in CPP subjects and the usefulness of its measurement in the diagnosis of CPP.

Growth hormone therapy in patients with short stature homeobox-gene (SHOX) deficiency.

Short stature homeobox (SHOX) gene is located in the pseudoautosomal region 1 on the distal end of the X and Y chromosomes at Xp22.3 and Yp11.3. The haploinsufficiency of SHOX is correlated with short stature, Leri-Weill dyschondrosteosis, and Langer mesomelic dysplasia. Subjects with Turner syndrome (TS) present a SHOX haploinsufficiency that appears to be substantially responsible for their short stature. Several studies have shown a positive response to GH therapy in patients with TS. Short children with SHOX haploinsufficiency do not spontaneously catch up to attain a normal final height. Considering the positive effects obtained in patients with TS, GH therapy has been proposed for short stature due to isolated SHOX haploinsufficiency. The aim of this paper is to summarize the current data on GH administration in patients with SHOX haploinsufficiency. The conclusion is that GH therapy, at the same dosage used in patients with TS, induces a sustained catch-up growth and a height velocity and adult height gain in short patients with SHOX haploinsufficiency.

Pituitary height and neuroradiological alterations in patients with Prader-Labhart-Willi syndrome.

Prader-Willi syndrome (PWS), a genetic disorder due to an alteration in the paternally derived long arm of chromosome 15, is characterized by a complex clinical picture (short stature, obesity, hypogonadism) that seems to be referable to as a central hypothalamic/pituitary dysfunction. To determine whether there is any diminution in the anterior pituitary gland or other neuroradiological alterations, we retrospectively analysed 91 patients with PWS (42 females, 49 males; age range: 0.7-16.8 years) by cerebral magnetic resonance imaging (MRI). Of these 91 patients, MRI analysis showed a reduction in pituitary height in 45 patients (49.4%), a complete absence of the posterior pituitary bright spot in six patients (6.6%) and other neuroradiological alterations in ten patients (11%). Altogether, neuroradiological alterations were present in 61 of the 91 (67%) patients. Our results indicate that neuroradiological alterations are more frequent in PWS patients than has been reported to date.

Rational approach to the treatment for heterozygous familial hypercholesterolemia in childhood and adolescence: a review.

Atherosclerosis represents a disease that begins in childhood and in which LDL cholesterol plays a pivotal role for the development of the pathology. Children and adolescents with high cholesterol levels are more likely than their peers to present cholesterol elevation as adults. The identification of genetic dyslipidemias associated with premature cardiovascular disease is crucial during childhood to delay or prevent the atherosclerotic process. Guidelines for the diagnosis and treatment of hypercholesterolemia during pediatric age are available from the National Cholesterol Education Program. A heart-healthy diet should begin at the age of 2 yr and a large number of studies have demonstrated no adverse effects on nutritional status, growth, pubertal development, and psychological aspects in children and adolescents limiting total and saturated fat intake. Pharmacotherapy should be considered in children over 10 yr of age when LDL cholesterol concentrations remain very high despite severe dietary therapy, especially when multiple risk factors are present. The only lipid-lowering drugs recommended up to now for childhood and adolescence are resins reported to be effective and well tolerated, although compliance is very poor because of unpalatability. The use of statins is increasing and seems to be effective and safe in children, even if studies enrolled a small number of patients and evaluated efficacy and safety for short-term periods. Recently, an interesting drug represented by ezetimibe has been found that may provide cholesterol-lowering additive to that reached with statin treatment. This review provides an update on recent advances in the diagnosis, therapy, and follow-up of familial hypercholesterolemia during pediatric age and adolescence.

High basal serum allopregnanolone levels in overweight girls.

OBJECTIVE: Several studies demonstrated that obese subjects have a hyperactive hypothalamic-pituitary-adrenal axis and that sex steroid hormones have been closely related to the regulation of adiposity, either through direct or indirect physiological mechanisms. Allopregnanolone (3alpha-hydroxy-5alpha-pregn-20-one; AP) is a circulating neuroactive steroid hormone involved in the modulation of behavioral functions, stress and neuroendocrine axis. The aim of our study was to evaluate basal serum AP levels in obese children. SUBJECTS AND MEASUREMENTS: We studied 27 normal weight (NW) and 23 overweight (OW) girls. Gonadotropins and steroid hormones were assessed in all patients. RESULTS: Basal AP concentrations in OW girls were significantly higher than in NW controls (P=0.013). There was no difference found between the other gonadal and adrenal hormones. Considering the pubertal stage, we demonstrated that obese pubertal girls presented higher AP concentrations than prepubertal and pubertal NW ones (P=0.020), and higher dehydroepiandrosterone sulfate (DHEAS) levels with respect to prepubertal obese girls, and prepubertal and pubertal NW patients (P=0.025). AP and DHEAS were significantly directly related to weight (r=0.31 and r=0.54, respectively) and body mass index (r=0.29 and r=0.34, respectively). In pubertal OW girls, a significant positive correlation between AP and DHEAS (r=0.60), A (r=0.72) and luteinizing hormone (r=0.64) levels was demonstrated. CONCLUSION: The present study demonstrates that AP is hypersecreted in children and adolescent with OW involving DHEAS concentrations, too. Our data suggest a possible role of AP in the regulation of neuroendocrine axis related to obesity. We can also speculate that in OW girls, who could manifest emotional and behavioral problems, a part of higher levels of this neuroactive steroid might act as gamma-aminobutyric acid agonist producing anxiolytic-sedative effects.

Increased liver enzymes and hormonal therapies in girls and adolescents with Turner syndrome.

Elevated liver enzymes can be seen relatively frequently in patients with Turner syndrome (TS), while the pathogenesis of this remains unclear. Our epidemiological and prospective study aimed to investigate: a) the natural 2-yr course of liver disease in a selected cohort of young patients with TS, who had been preliminarily recruited on the basis of persistently elevated liver enzymes; b) the role of prolonged hormonal therapies in the etiology of liver dysfunction. From an overall population of 214 TS patients younger than 20 yr, only 19 (8.9%) were recruited, according to the following inclusion criteria: increased serum concentrations of one or more liver enzymes, exceeding the uppermost limit of the respective normal ranges, and persistence of these liver alterations for 6 months after the preliminary assessment. On the basis of the results of this prospective study, we can conclude that: a) the prevalence of liver abnormalities in girls and adolescents with TS is much lower and more strictly related to hormonal therapies than in TS adults; b) both autoimmunity and obesity are not frequently involved in the etiology of TS liver dysfunction; c) liver damage is either mild or moderate and its severity is not conditioned by karyotype; d) its course may be self-limiting; e) its natural history may be characterized in some cases by a slight deterioration of intrahepatic cholestasis, with no negative repercussions on liver synthetic function.

Relationship between body mass index and insulin measured during oral glucose tolerance testing in severely obese children and adolescents.

PRIMARY OBJECTIVE: The study evaluated the accuracy of body mass index (BMI) in detecting hyperinsulinaemia during oral glucose tolerance testing (OGTT) in severely obese children. RESEARCH DESIGN: A cross-sectional study was carried out. MATERIALS AND METHODS: A total of 118 obese children and adolescents (49 females and 69 males) aged 6-19 years were consecutively studied at an outpatient paediatric clinic. Hyperinsulinaemia was defined as a value of log-transformed fasting insulin >/= 80th percentile and OGTT hyperinsulinaemia as a value of the log-transformed area under the curve (AUC) of insulin >/= 80th percentile. The study hypothesis was tested using a logistic regression model with hyperinsulinaemia as the outcome variable and the z-score of BMI corrected for age (z-BMI(age)) as the predictor variable. Receiver-operator characteristic (ROC) curves were used to evaluate accuracy. RESULTS: The mean (SD) BMI for age of the children was 28.6 (4.0) kg m(-2), corresponding to 2.2 (0.5) standard deviation scores. The odds ratio (OR) of OGTT hyperinsulinaemia was 2.0 (95% CI 1.2-3.3; p = 0.007) for each unit increase of z-BMI(age) and the corresponding ROC-AUC was 0.74 (95% CI 0.61-0.86; p = 0.0001). In comparison, the OR of fasting hyperinsulinaemia was 1.1 (95% CI 0.7-1.7; p = 0.716) for each unit increase of z-BMI(age) and the corresponding ROC-AUC was 0.49 (95% CI 0.35-0.62; p = 0.863). CONCLUSION: BMI is reasonably accurate in detecting OGTT hyperinsulinaemia in severely obese children.

High serum allopregnanolone levels in girls with precocious puberty.

Allopregnanolone, a circulating neuroactive steroid hormone, is involved in the modulation of behavioral functions, stress, and the neuroendocrine axis. The aim of this study was to evaluate serum allopregnanolone concentrations in girls with central precocious puberty (n = 12), girls with normal pubertal development at the same pubertal stage (n = 17), and prepubertal girls (age-matched; n = 16). Gonadotropin and steroid hormones (allopregnanolone, cortisol, dehydroepiandrosterone sulfate, and E2) were assessed in all patients. GnRH and ACTH stimulation tests were performed in all girls with central precocious puberty and in some pubertal controls. Basal allopregnanolone levels in girls with central precocious puberty were significantly higher than in normal controls (P < 0.01). Allopregnanolone levels increased significantly after GnRH and ACTH stimulation tests (P < 0.05) both in girls with central precocious puberty and in those with normal pubertal development. There was no difference found between the peak values. In conclusion, our study shows that allopregnanolone is hypersecreted in central precocious puberty, confirming a pubertal stage-related increase in its levels during normal pubertal development. The increase in serum allopregnanolone after GnRH and ACTH stimulation tests demonstrates that both adrenal cortex and gonads are sources of this neuroactive steroid.

Rhabdomyoma of a rare type in a child: case report and literature review.

We describe a 9-year-old boy who presented with dyspnea and with a neck mass which was initially described as a thyroid nodule. At the end of the diagnostic-therapeutic research this mass was finally diagnosed as an adult rhabdomyoma originating from the mediastinum. This is an extremely rare tumor which is usually found in the adult population.

Diagnosis of central precocious puberty: endocrine assessment.

The new methods which are currently available have provided substantial help in performing the differential diagnosis of CPP, especially in detecting very early modifications of gonadotropin secretion. Nocturnal sampling is not a practical tool and generates discomfort for patients, and daytime samples do not yet have sufficient sensitivity; thus, determination of LH levels after GnRH stimulation is the most important test. We emphasize that the use of the GnRH agonist test improves the discrimination of the endocrine investigation, making it easier to differentiate CPP from other conditions, such as thelarche. Determination of sex steroids is necessary, but its use in isolation is not recommended.

Genetics and molecular biology of the GHRH-GH-IGF-I axis.

In this paper, the genetics and molecular biology of the GHRH-GH-IGF-I (Growth Hormone Releasing hormone-Growth Hormone-Insulin like Growth Factor I) axis involved in the pathogenesis of short stature are reviewed. Short stature associated with GH deficiency is estimated to occur in about 1/4000-10,000 live births; 3-30% of cases affect first-degree relatives, suggesting a genetic aetiology. Identification of such molecular defects is very recent and dependent on new findings on the physiology of GHRH-GH-IGF-I axis: for example the pituitary-specific transcription factors and their mutations have only been described in the last few years. The epidemiological importance of the identified molecular defect depends on the level of the axis involved, but the prevalence of some of these genetic defects is probably underestimated. Time will tell what the practical relevance of these findings is and what the clinical features of the new mutations are; we will probably learn something more about the GHRH-GH-IGF-I axis: to date, no mutations have been reported regarding the GHRH gene or the IGF-I receptor.