Transient Isolated, Idiopathic Growth Hormone Deficiency-A Self-Limiting Pediatric Disease with Male Predominance or a Diagnosis Based on Uncertain Criteria? Lesson from 20 Years' Real-World Experience with Retesting at One Center.

In the majority of children with growth hormone (GH) deficiency (GHD), normal GH secretion may occur before the attainment of final height. The aim of the study was to assess the incidence of persistent and transient GHD and the effectiveness of recombined human GH (rhGH) therapy in children with isolated, idiopathic GHD with respect to the moment of therapy withdrawal and according to different diagnostic criteria of GHD. The analysis included 260 patients (173 boys, 87 girls) with isolated, idiopathic GHD who had completed rhGH therapy and who had been reassessed for GH and IGF-1 secretion. The incidence of transient GHD with respect to different pre- and post-treatment criteria was compared together with the assessment of GH therapy effectiveness. The incidence of transient GHD, even with respect to pediatric criteria, was very high. Normal GH secretion occurred before the attainment of near-final height. Application of more restricted criteria decreased the number of children diagnosed with GHD but not the incidence of transient GHD among them. Poor response to GH therapy was observed mainly in the patients with normal IGF-1 before treatment, suggesting that their diagnosis of GHD may have been a false positive. Further efforts should be made to avoid the overdiagnosis GHD and the overtreatment of patients.

Involvement of Sirtuin 1 in the Growth Hormone/Insulin-like Growth Factor 1 Signal Transduction and Its Impact on Growth Processes in Children.

The regulation of growth processes in children depends on the synthesis of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Insulin-like growth factor 1, which is mainly secreted in the liver in response to GH, is the main peripheral mediator of GH action. Newly discovered factors regulating GH secretion and its effects are being studied recently. One of them is sirtuin 1 (SIRT1). This NAD+-dependent deacetylase, by modulating the JAK2/STAT pathway, is involved in the transduction of the GH signal in hepatocytes, leading to the synthesis of IGF-1. In addition, it participates in the regulation of the synthesis of GHRH in the hypothalamus and GH in the somatotropic cells. SIRT1 is suggested to be involved in growth plate chondrogenesis and longitudinal bone growth as it has a positive effect on the epiphyseal growth plate. SIRT1 is also implicated in various cellular processes, including metabolism, cell cycle regulation, apoptosis, oxidative stress response, and DNA repair. Thus, its expression varies depending on the different metabolic states. During malnutrition, SIRT1 blocks GH signal transduction in hepatocytes to reduce the IGF-1 secretion and prevent hypoglycemia (i.e., it causes transient GH resistance). In this review, we focused on the influence of SIRT1 on GH signal transduction and the implications that may arise for growth processes in children.

Contribution of Ghrelin to the Pathogenesis of Growth Hormone Deficiency.

In this review we described the interactions between ghrelin and the growth hormone (GH)-insulin-like growth factor 1 (IGF-1) axis in children and adults with growth hormone deficiency (GHD). A possible involvement of these interactions in the pathogenesis of unexplained cases of GHD was suggested. Current research provides more and more details to the knowledge on the circadian rhythm of ghrelin. We gathered reports on the decreasing effect of Helicobacter pylori-related chronic gastritis on the number of ghrelin immunopositive cells and the consequent decrease in ghrelin serum concentration. The gastrointestinal tract microflora modification of the ghrelin action, by the mechanism of molecular mimicry, was also stressed. Moreover, the mutual relationships between ghrelin and the TSH-FT4/FT3 axis in growth and metabolic processes are described. It is to be recalled that FT4 and FT3 exert a permissive impact on IGF-1 action and, in turn, GH, in reaction mediated by IGF-1, enhances the monodeiodination of FT4 to FT3. Finally, we discussed the latest attempts to use the GH secretagogue receptor (GHS-R) analogues for possible diagnostic and therapeutic purposes.

Strong Positive Correlation between TSH and Ghrelin in Euthyroid Non-Growth Hormone-Deficient Children with Short Stature.

The growth processes in children depend on the proper functioning of some hormones and growth factors. Recently, a positive correlation between ghrelin and TSH (thyroid stimulating hormone) in patients with hyper- and hypothyroidism was proved. Moreover, in hypothyroid rats with high ghrelin concentration, growth hormone (GH) and insulin-like growth factor I (IGF-I) secretion was suppressed. We analyzed these relationships in euthyroid prepubertal children with idiopathic short stature (ISS). The analysis comprised concentration of ghrelin, GH in stimulating tests and during the night, as well as IGF-I, TSH, free thyroxine (FT4) and free triiodothyronine (FT3) in 85 children with ISS (36 girls, 49 boys) aged 9.65 ± 3.02 years (mean ± SD). A strong positive correlation between ghrelin and TSH was confirmed (r = +0.44, p < 0.05). A higher ghrelin but lower nocturnal GH and lower IGF-I were observed in children with higher normal TSH concentration than those in children with lower normal TSH. Interestingly, alterations of TSH level were without any impact on FT4 and FT3 concentrations. Summing up, in ISS prepubertal euthyroid children, ghrelin and TSH secretion are closely related. On the other hand, the higher the TSH, the lower the nocturnal GH and IGF-I levels. The contribution of the above findings in deterioration of growth processes requires further studies.

Nutritional Status in Short Stature Children Is Related to Both Ghrelin and Insulin-like Growth Factor I Concentrations.

OBJECTIVES: Ghrelin plays an important role in the growth processes in children. In addition, it regulates appetite. The aim of the study was to assess ghrelin and insulin-like growth factor type I (IGF-I) concentrations in children with idiopathic short stature, dependent on nutritional status. METHODS: The study group included 116 children, ages 10.6 ±â€Š3.5 years (mean ±â€Šstandard deviation), with idiopathic short stature (height <-2.0 standard deviation scores [SDS], maximal growth hormone [GH] secretion during 2 GH-stimulating tests->10 ng/mL). In each child, fasting ghrelin, IGF-I, insulin-like growth factor binding protein 3 (IGFBP-3), glucose, insulin, lipids, leptin, adiponectin, and resistin concentrations were assessed. The IGF-I/IGFBP-3 molar ratio was calculated to determine the IGF-I bioavailability. According to body mass index SDS calculated for height age, the children were divided into 3 groups: poorly nourished (thin), normal, and obese. The control group consisted of 19 healthy children, ages 11.0 ±â€Š3.5 years, with normal body weight and height. RESULTS: Ghrelin concentration was significantly higher in short, thin children than in short, obese children (1458.3 ±â€Š798.5 vs 917.2 ±â€Š303.0 pg/mL; P < 0.005). In turn, IGF-I/IGFBP-3 molar ratio was significantly lower in short, thin children than in short, obese children (0.16 ±â€Š0.06 vs 0.28 ±â€Š0.15; P < 0.005). CONCLUSIONS: In short, thin children, despite elevated ghrelin production, the low IGF-I concentration is observed, probably due to undernutrition and worse IGF-I formation. In short, normal-weight children and in short, obese ones, ghrelin and IGF-I production is normal, and it seems that mechanisms responsible for their short stature are other than low IGF-I.

In children with autoimmune thyroiditis CTLA4 and FCRL3 genes--but not PTPN22--are overexpressed when compared to adults.

BACKGROUND: Numerous genetic studies revealed several susceptibility genes of autoimmune thyroid diseases (AITD), including CTLA4, PTPN22 and FCRL3. These immune-modulating genes are involved in genetic background of AITD among children and adult patients. However, possible age-related differences in overexpression of these genes remain unclear. PURPOSE: The goal of this single centre cohort study was evaluation of expression levels of three (3) genes CTLA4, PTPN22 and FCRL3 in adult patients and children with autoimmune thyroiditis. METHODS: A total of 47 patients--24 adults (mean age--47.7 years) and 23 children (mean age--12.4 years) with autoimmune thyroiditis were assessed for the level of expression of CTLA4, PTPN22 and FCRL3 genes, utilizing ABI PRISM' 7500 Sequence Detection System (Applied Biosystem, Foster City, CA, USA). RESULTS: The overexpression of PTPN22 (mean RQ = 2.988) and FCRL3 (mean RQ = 2.544) genes were confirmed in adult patients with autoimmune thyroiditis, at the same time the expression level of CTLA4 gene was significantly decreased (mean RQ = 0.899) (p < 0.05). Similar discrepancies were not observed in children with autoimmune thyroiditis in whom overexpression of all three genes--CTLA4, PTPN22 and FCRL3--was observed. Differences in CTLA4 and FCRL3 genes expression levels in patients with autoimmune thyroiditis were found depending on the age, with increased expression levels of CTLA4 (mean RQ = 3.45 1) and FCRL3 (mean RQ = 7.410) in children when compared to adults (p < 0.05) (Mann-Whitney's U-test). There were moderate negative linear correlations between two genes in question (CTLA4 and FCRL3) expression level and patients' age [correlation coefficient (r) = -0.529 (p < 0.0002) and -0.423 (p < 0.0032), respectively; Spearman's rank correlation test]. CONCLUSION: Our results are consistent with the hypothesis that there are few age-dependent genetic differences as regards autoimmune thyroiditis in adults and children. Accordingly, CTLA4 and FCRL3 genes overexpression may play an important role in children suffering from autoimmune thyroiditis.

Neural network models - a novel tool for predicting the efficacy of growth hormone (GH) therapy in children with short stature.

INTRODUCTION: The leading method for prediction of growth hormone (GH) therapy effectiveness are multiple linear regression (MLR) models. Best of our knowledge, we are the first to apply artificial neural networks (ANN) to solve this problem. For ANN there is no necessity to assume the functions linking independent and dependent variables. The aim of study is to compare ANN and MLR models of GH therapy effectiveness. MATERIAL AND METHODS: Analysis comprised the data of 245 GH-deficient children (170 boys) treated with GH up to final height (FH). Independent variables included: patients' height, pre-treatment height velocity, chronological age, bone age, gender, pubertal status, parental heights, GH peak in 2 stimulation tests, IGF-I concentration. The output variable was FH. RESULTS: For testing dataset, MLR model predicted FH SDS with average error (RMSE) 0.64 SD, explaining 34.3% of its variability; ANN model derived on the same pre-processed data predicted FH SDS with RMSE 0.60 SD, explaining 42.0% of its variability; ANN model derived on raw data predicted FH with RMSE 3.9 cm (0.63 SD), explaining 78.7% of its variability. CONCLUSION: ANN seem to be valuable tool in prediction of GH treatment effectiveness, especially since they can be applied to raw clinical data.

Prevalence of autoantibodies against some selected growth and appetite-regulating neuropeptides in serum of short children exposed to Candida albicans colonization and/or Helicobacter pylori infection: the molecular mimicry phenomenon.

OBJECTIVES: Many of peptides synthesized in gastrointestinal tract (GI) and adipose tissues, regulate growth and food intake. The GI microflora is an antigenic source. Based on the molecular mimicry hypothesis, intestinal microbe-derived antigens may trigger the production of autoantibodies cross-reacting with some neuropeptides. DESIGN: The aim of the study was to assess whether in idiopathic short stature (ISS) children with Candida albicans (C.albicans) colonisation and/or Helicobacter pylori (H.pylori) infection the autoantibodies (in positive levels) against selected neuropeptides [anti-NP Abs(+)]: ghrelin, leptin, orexin A, αMSH are more prevalent than in Controls. SETTING: The study group comprised 64 children with ISS and 36 children with normal height (Controls). In each child, IgG antibodies against H.pylori, ghrelin, leptin, orexin A and αMSH were assessed in serum, while presence of C.albicans - in stool samples. RESULTS: The higher prevalence of anti-NP Abs(+) in ISS children with C.albicans and/or H.pylori than in normal height children with the colonization in question (34.4% vs 21.1%, p<0.01) was found. The prevalence of anti-NP Abs(+) in groups of children without C.albicans and H.pylori were low, anti-NP Abs(+) were detected in 9.4% of ISS children only, while in Controls they were not found. CONCLUSIONS: In short children with C.albicans and/or H.pylori the incidence of autoantibodies against selected neuropeptides is high. It probably is connected with molecular mimicry between antigens of these microbiota and the mentioned peptides. It is tempting to speculate that presence of cross-reacting autoantibodies against regulatory neuropeptides may results in worse growth velocity. However, further studies are necessary to elucidate this issue.

Sirtuin 1 serum concentration in healthy children - dependence on sex, age, stage of puberty, body weight and diet.

Introduction: Sirtuin 1 (SIRT1) is known to be involved in sensing cellular energy levels and regulating energy metabolism. This study aimed to evaluate fasting serum SIRT1 levels in healthy children, and to analyse the influence of age, sex, puberty, body weight, height, and diet on its concentration. Methods: 47 healthy children aged 4-14 with weight and height within normal range and no chronic disease were included into the study. Fasting serum SIRT1 concentrations were estimated by Enzyme Linked Immunosorbent Assay (ELISA). Results: Results showed that serum SIRT1 concentrations in healthy children did not differ with respect to sex, age, height, weight and puberty. Whereas, it appeared that a higher frequency of fruits, vegetables and dairy products consumption was associated with an increase in serum SIRT1 levels. Discussion: Studying SIRT1 in the context of children's health may have implications for a broader understanding of growth processes, pubertal development, metabolic disorders and nutrition.

Relationship between Serum Sirtuin 1 and Growth Hormone/Insulin-like Growth Factor 1 Concentrations in Children with Growth Hormone Deficiency and Idiopathic Short Stature.

Sirtuin 1 (SIRT1) inhibits growth hormone (GH) intracellular signaling for the insulin-like growth factor 1 (IGF-1) synthesis via the janus kinase (JAK)/signal transducer and activator of transcription proteins (STATs) pathway. The aim of this study was to compare SIRT1 concentrations in children with GH deficiency (GHD) and so-called idiopathic short stature (ISS, non-GH deficient), in order to determine the possible impact of changes in serum SIRT1 concentrations on the GH-IGF-1 axis. The study group included 100 short-stature children: 38 with GHD and 62 with ISS (maxGH in two stimulation tests <10 and ≥10 ng/mL, respectively). The control group consisted of 47 healthy, normal-height children. For each child, the concentrations of SIRT1, IGF-1 and insulin-like growth factor-binding protein 3 (IGFBP-3) were determined and the IGF-1/IGFBP-3 molar ratio was calculated. The level of SIRT1 was significantly higher in both groups of short children than in the controls (p < 0.0001), but there were no differences between GHD and ISS (mean ± SD: 0.89 ± 0.45 for ISS; 1.24 ± 0, 86 for GHD; and 0.29 ± 0.21 for controls). A significant negative correlation was found between SIRT1 and height standard deviation score (SDS), IGF-1 and IGF-1/IGFBP-3, but not between SIRT1 and maxGH. Elevated SIRT1 levels may serve as one of the mechanisms through which the secretion of IGF-1 is reduced in children with short stature; however, further research is required to confirm this issue.

Comparison of the Clinical Utility of Two Insulin Resistance Indices: IRI-HOMA and IRI-Belfiore in Diagnosing Insulin Resistance and Metabolic Complications in Children Based on the Results Obtained for the Polish Population.

Background: Recognizing insulin resistance (IR) in children remains challenging due to uncertain IRI-HOMA cut-offs and unclear recommendations for evaluating IR based on OGTT. In our study, we compare the effectiveness of IRI-HOMA and IRI-Belfiore (OGTT-based) in detecting IR and its metabolic complications in children. Methods: The analysis included 553 children who were hospitalized at the Department of Endocrinology and Metabolic Diseases of the Polish Mother's Memorial Hospital Research Institute (PMMH-RI) in Lodz, Poland, between 2002 and 2018 due to various reasons-of these, 67.5% were girls. All underwent OGTT for glucose and insulin assessment. IR diagnosis relied on IRI-HOMA and IRI-Belfiore. IR based on IRI-HOMA was evaluated using three criteria: (A) >2.5; (B) >2.67 in boys and >2.22 in girls before puberty and >5.22 and >3.82 during puberty, respectively; (C) >95th percentile according to charts for IRI-HOMA in children. Results: Prepubertal children exhibited significantly lower IRI-HOMA and IRI-Belfiore than their pubertal counterparts (p < 0.00005). IRI-HOMA and IRI-Belfiore values positively correlated with age and BMI SDS value (p < 0.000001 for all calculations). As many as 26% to 46.9% of children with normal IRI-HOMA showed elevated IRI-Belfiore, with notably higher levels of triglycerides, a lower HDL cholesterol fraction, and a lower HDL/total cholesterol ratio in this subgroup. Conclusions: A notable proportion of children exhibited elevated IRI-Belfiore levels despite having normal IRI-HOMA values. This suggests the possibility of peripheral IR preceding hepatic IR in children-omitting an OGTT may therefore lead to overlooking cases of IR. Children diagnosed with IR via OGTT displayed significantly poorer lipid profiles compared to those without IR (characterized by normal values in both IRI-HOMA and IRI-Belfiore). This underscores the ability of OGTT-derived IR indices to identify individuals at risk of developing complications associated with obesity and IR before the onset of metabolic syndrome (MS) symptoms. If IR is already detected in children based on fasting glucose and insulin levels (IRI-HOMA), further evaluation may not be warranted, as OGTT results often simply confirm the diagnosis.

Frequency of the E23K polymorphism of the KCNJ11 gene in children born small for gestational age and its influence on auxological and metabolic parameters in the prepubertal period.

BACKGROUND: The E23K variant of the KCNJ11 gene is possibly responsible for changes in insulin secretion during the fetal life. We tried to assess the influence of the E23K variant on birth weight and metabolic profile in prepubertal children born small for gestational age (SGA). SUBJECTS: One hundred and twenty-three SGA and 132 born appropriate for gestational age (AGA) children were genotyped for the E23K variant. Lipids, glucose, and insulin concentrations during oral glucose tolerance test were assessed in 112 SGA prepubertal children. RESULTS: There were no significant differences between the frequency of the E23K variant in SGA and AGA children. In SGA children with E23K, the mean birth weight was significantly higher than in the E23E group. Body mass index, glucose, insulin, and lipids were not different between the E23K, E23E, and K23K groups. CONCLUSIONS: The higher birth weight in SGA children with the E23K variant may be related to higher insulin concentrations in the fetal period. The E23K variant did not affect metabolic disorders in prepubertal SGA children.

Significant increase of IGF-I concentration and of IGF-I/IGFBP-3 molar ratio in generation test predicts the good response to growth hormone (GH) therapy in children with short stature and normal results of GH stimulating tests.

BACKGROUND: Insulin-like growth factor-I (IGF-I) generation test has been introduced for the assessment of growth hormone (GH) sensitivity, however, its significance in predicting growth response to GH therapy has also been brought up. The molar ratio of IGF-I to its binding protein-3 (IGFBP-3) determines IGF-I bioavailability. AIMS: Evaluation of usefulness of IGF-I and IGFBP-3 generation test in predicting the effectiveness of rhGH therapy in children with short stature. PATIENTS AND METHODS: The analysis comprised 60 children with short stature, normal results of GH stimulating tests but decreased IGF-I secretion. In all the patients, GH insensitivity was excluded on the basis of IGF-I and IGFBP-3 generation test. Next, GH therapy was administered and height velocity (HV), together with IGF-I and IGFBP-3 secretion, was assessed every year, during 3 years. The comparative group consisted of 30 children with partial GH deficiency (pGHD). RESULTS: Both IGF-I secretion and IGF-I/IGFBP-3 molar ratio increased significantly during generation test (p<0.05) and - further - during GH therapy (however insignificantly), together with at least doubling of pretreatment HV. There was no significant difference between the studied group of patients and children with pGHD. CONCLUSIONS: Significant increase of IGF-I in generation test speaks for GH therapy effectiveness in short children, despite normal results of GH stimulating tests.

Osteoporosis as the First Sign of Cushing's Disease in a Thin 16-Year-Old Boy-A Case Report.

Cushing's disease (CD) is an extremely rare diagnosis in children. In this report, we present the case of an almost 16-year-old, short and thin boy with CD, the first symptoms of which were spinal pain and vertebral fractures as a result of osteoporosis. In light of his growth retardation and short stature, the boy underwent diagnostics, which excluded growth hormone (GH) deficiency, hypothyroidism and celiac disease. Finally, based on cortisol profile results, dexamethasone suppression tests and bilateral sampling during catheterization of the inferior petrosal sinuses, CD was diagnosed.

The Variability of Vitamin D Concentrations in Short Children with Short Stature from Central Poland-The Effects of Insolation, Supplementation, and COVID-19 Pandemic Isolation.

The aim of the study was to investigate the effects of seasonal variability of insolation, the implementation of new recommendations for vitamin D supplementation (2018), and the SARS-CoV-2 pandemic lockdown (2020) on 25(OH)D concentrations in children from central Poland. The retrospective analysis of variability of 25(OH)D concentrations during the last 8 years was performed in a group of 1440 children with short stature, aged 3.0-18.0 years. Significant differences in 25(OH)D concentrations were found between the periods from mid-2014 to mid-2018, from mid-2018 to mid-2020, and from mid-2020 to mid-2022 (medians: 22.9, 26.0, and 29.9 ng/mL, respectively). Time series models created on the grounds of data from 6 years of the pre-pandemic period and used for prediction for the pandemic period explained over 80% of the seasonal variability of 25(OH)D concentrations, with overprediction for the first year of the pandemic and underprediction for the second year. A significant increase in 25(OH)D concentrations was observed both after the introduction of new vitamin D supplementation guidelines and during the SARS-CoV-2 pandemic; however, the scale of vitamin D deficiency and insufficiency was still too high. Time series models are useful in analyzing the impact of health policy interventions and pandemic restrictions on the seasonal variability of vitamin D concentrations.

GH-secreting pituitary adenoma in the course of McCune­Albright syndrome in a 21-year-old patient complicated by hepatocellular carcinoma.

Not required for Clinical Vignette.

The incidence of insulin resistance based on indices calculated using the HOMA and Belfiore methods and its impact on the occurrence of metabolic complications in prepubertal children born small for gestational age.

INTRODUCTION: Children born small for gestational age (SGA) are predisposed to obesity, insulin resistance (IR), and lipid disorders. The HOMA-IR index is commonly used to assess IR (IRIHOMA), calculated from fasting glucose and insulin. However, sometimes, during the oral glucose tolerance test (OGTT), elevated and prolonged postprandial insulin secretion is observed despite normal fasting insulin levels. IRIBelfiore is an IR index that analyses glucose and insulin levels during OGTT according to the method proposed by Belfiore. THE AIM OF THE STUDY: was to assess the frequency of IR based on IRIHOMA and IRIBelfiore results in SGA children aged 6-8 years, after catch-up phenomenon, to determine the usefulness of IRIBelfiore in diagnosis of IR and in predicting future metabolic complications. MATERIAL AND METHODS: In 129 SGA normal-height children, aged 6-8 years, height, weight, waist circumference, blood pressure, as well as lipids, IGF-1, cortisol, C-peptide, leptin, adiponectin, and resistin concentrations were measured. The glucose and insulin concentrations were evaluated at 0, 60, and 120 minutes of OGTT. RESULTS: IRIHOMA was normal in all children, while elevated IRIBelfiore was found in 22.5% of them. Children with IR diagnosed by IRIBelfiore were taller, had higher blood pressure, higher leptin, and lower HDL-cholesterol concentrations. CONCLUSIONS: It seems worth recommending IRIBelfiore derived from OGTT as a valuable diagnostic tool for identifying IR in SGA prepubertal children. Abnormal IRIBelfiore is related to higher blood pressure and lower HDL-cholesterol concentration in this group.

Growth hormone (GH) peak after falling asleep reflects spontaneous nocturnal GH secretion, however is not corresponding to the results of GH stimulating tests in children with short stature.

OBJECTIVE: Growth hormone (GH) secretion is characterized by a pulsatile, circadian rhythm, with the highest concentrations at night hours. Evaluation of nocturnal GH secretion may be truncated to 6 hours. Growth hormone stimulating tests are the standard method of assessment of GH secretion. In Poland, the assessment of GH peak during 2 hours after falling asleep was introduced as a screening procedure in children, suspected for GH deficiency. The aim of current study was to compare the results of a screening test with GH secretion during 6-hour nocturnal profile and with the results of GH stimulating tests, as well as with IGF-I secretion in children with short stature. METHODS: In 72 short children, GH concentrations were measured every 30 minutes during first 6 hours after falling asleep and in two GH stimulating tests (the cut-off level of GH peak for all the tests was 10.0 ng/ml). Also, IGF-I concentrations were measured and expressed as IGF-I SDS for age and sex. RESULTS: The screening test results correlated significantly with both GH peak in 6-hour profile and mean GH concentration, and the area under the curve (AUC) in 6 hour profile (r= 0.94, r=0.90 and r=0.89, respectively, p<0.05) but not with GH peak in stimulating tests (r=0.07, NS). There was no correlation between IGF-I secretion and any of the analyzed parameters of spontaneous and stimulated GH secretion. CONCLUSIONS: The results of screening test seem to reflect overnight GH secretion in short children, remaining, however, discordant with the results of GH stimulating tests and with IGF-I secretion.

High concentration of ghrelin in children with growth hormone deficiency and neurosecretory dysfunction.

BACKGROUND: The role of endogenous ghrelin in the growth process of children is unclear. The aim of the present study was to assess ghrelin concentrations in children with growth hormone deficiency (GHD), neurosecretory dysfunction (NSD) and idiopathic short stature (ISS) in comparison to healthy controls. MATERIAL: One hundred and forty seven children (61 girls and 86 boys), aged 3.7-16.8 years (mean±SD: 10.7±3.44 years) with short stature (below -2.0 SD) were qualified into the study. In each child, fasting ghrelin and insulin-like growth factor type I (IGF-I) concentrations were measured and growth hormone (GH) secretion was assessed after falling asleep and during two GH-stimulating tests. According to maximal GH concentrations, children were qualified into GHD, NSD and ISS group. Additionally, depending on biological development, the children were divided on younger and older subgroups. The control group consisted of 19 healthy children with normal height and body mass. RESULTS: Ghrelin concentrations in GHD (1847.5±1444.3 pg/mL) and NSD (1809.3±983.5 pg/mL) were significantly higher than in ISS (1218.1±646.8 pg/mL) and in Controls (924.9±318.4 pg/mL). A comparison of ghrelin concentrations in older and younger children within the same diagnostic group, showed statistically higher ghrelin levels in younger than in older children (except of NSD group, in which the difference reached the border of statistical significance). CONCLUSIONS: Ghrelin concentration is elevated in GHD and NSD children. Independently of GH and IGF-I secretion disorders type, ghrelin concentrations decrease with the children' age. The higher concentration of ghrelin in ISS than in Controls suggests the presence of GH-independent factors increasing ghrelin secretion by X/A cells in the gastric oxyntic mucosa.

Ghrelin concentration is correlated with IGF-I/IGFBP-3 molar ratio but not with GH secretion in children with short stature.

OBJECTIVES: In children with growth hormone deficiency (GHD) and neurosecretory dysfunction (NSD) ghrelin concentrations are significantly higher than in children with idiopathic short stature (ISS), however the correlation between serum ghrelin and growth hormone (GH) is not observed. The aim of the study was to compare ghrelin concentrations with IGF-I/IGFBP3 molar ratio in children with short stature due to different etiology. MATERIAL: Analysis comprised 136 children (58 girls and 78 boys), aged 3.86-16.82 years with short stature (below -2.0 SD); in 21 of them GHD was diagnosed, in 23 - NSD and 92 - ISS. In each child, fasting ghrelin, insulin-like growth factor type I (IGF-I) and its binding protein type 3 (IGFBP-3) concentrations were measured. The results were analysed separately in younger and in older children. Depending on IGF-I/IGFBP-3 molar ratio, children were divided into two (2) groups: with lower IGF-I/IGFBP-3 and with higher IGF-I/IGFBP-3 ratio value. RESULTS: Both in younger and in the older age groups, ghrelin concentration was significantly higher in children with lower IGF-I/IGFBP-3 ratio than in children with higher IGF-I/IGFBP-3 value (1937.3±1232.4 vs 1365.3±632.1 pg/ml in younger children and 1205.4±548.8 vs 867.4±282.9 pg/ml in older children). The negative correlation between ghrelin and IGF-I/IGFBP-3 ratio was observed in both age groups. Not only children with GHD and NSD, but also as much as 39% out of all children with ISS were qualified into the subgroups with lower IGF-I/IGFBP-3 ratio. CONCLUSIONS: Ghrelin secretion is elevated in children with lower IGF-I/IGFBP-3 ratio. It seems that lower bioactivity of IGF-I is stimulating factor for ghrelin synthesis.